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FAQs

  • Miscellaneous Questions
    • What is the purpose of the 25C incubation step when using Q-Script-RT during cDNA synthesis?
      The purpose of the 25C incubation step during cDNA synthesis is to allow annealing and extension of the random primers. Since the primers are short, a lower temperature is required. Omission of this step will result in inefficient cDNA synthesis.
    • How are PerfeCTa® microRNA assays designed?
      PerfeCTa microRNA assays are designed with primer design software according to the following criteria: • Optimized primer Tm designed to match the Universal PCR Primer • Universal cycling conditions to ensure robust amplification for all assays in profiling experiments • No self-complementarity or primer dimer artifacts with the PerfeCTa Universal PCR Primer • Optimized PCR product size with melting temperature of 75-78°C
    • Do the PerfeCTa microRNA assays distinguish between closely related family members?
      PerfeCTa microRNA Assays will distinguish closely related family members are distinguished to varying degrees depending on the specific assay. The current microRNA assays have been designed primarily as a general profiling reagent that work with maximum efficiency with common PCR cycling conditions. Greater assay specificity can be achieved by increasing the annealing temperature of the PCR cycling from 60°C to 63°C with some cost to assay sensitivity. In some cases assays have been designed (for example, the let-7 family) that will distinguish closely related family members.
    • How are PerfeCTa microRNA assays validated?
      • Proper tissue or cell type specificity (where applicable) • No primer dimer or off-target amplification product • Good amplification efficiency tested with multiple input amounts of cDNA • Comparison of qPCR results to a no-poly(A) polymerase control must demonstrate significant differences in samples where the microRNA is present • A single melt peak observed at the expected amplicon melt temperature
    • What should I do if I suspect that my RNA contains RNase activity?
      If it is suspected that an RNA prep contains RNase activity, add RNase inhibitor to the reverse transcription reaction at a final concentration of 0.4 U/µl. Q-Script RT is a mixture of MMLV RT reverse transcriptase and Rnase inhibitor and should provide some safeguard against this problem. Q-Script RT is used in all of Quanta's cDNA synthesis kits: qScript™ cDNA Synthesis Kit (Cat# 95047), qScript™ cDNA SuperMix (Cat# 95048), qScript™ Flex cDNA Kit (Cat# 95049). If the RNA is grossly contaminated, another RNA prep should be used.
    • What are the sources of non-specific amplification products?
      The origin non-specific amplification could potentially arise from mRNA transcripts containing sequences similar to the microRNA assay sequence close to their 3’-ends. Specificity of the microRNA assay comes from a single microRNA-specific assay primer, thus, there is a slightly higher probability of non-specific amplification for microRNA detection than a typical two-step RT-qPCR assay for mRNA which employs two gene-specific primers. In general, amplification products are not produced from single primer reactions (microRNA-specific primer alone or UAP alone). Positive signals are dependent on inclusion of both the UAP and the microRNA-specific primer in the qPCR. The probability non-specific amplification products increases with increasing cDNA template in the qPCR reaction and when the microRNA of interest is rare or absent from the RNA sample. When observed, non-specific amplification can be reduced by increasing the temperature of the reverse transcriptase reaction to 45°C without compromising assay sensitivity. In addition, increasing the annealing temperature of the PCR cycling condition (up to 63°C) will reduce non-specific amplification at some cost to assay sensitivity. The most useful control to measure non-specific amplification is the no-poly(A) polymerase (no-PAP) control. Assay results should be considered negative if the difference in CTs from the plus-PAP and no-PAP reactions is less than 2 CTs.
    • What is the optimal amount of RNA input?
      The kit can is quantitative with 1 ug to 10 pg of total RNA in a 20 uL cDNA reaction. More than 1 ug can be used in larger reaction volumes scaled appropriately.
    • Does the RNA need to be DNAse treated?
      DNAse treatment is not necessary and not recommended for microRNA detection. qPCR reactions of no-RT controls or using genomic DNA as template do not produce amplification products. DNAse is often difficult to inactivate and residual DNAse activity will greatly decrease sensitivity of any RT-qPCR assay.
    • What assays should I use for normalization of the data?
      Use any assay or set of assays that are stable (do not change) with respect to the treatment or conditions of your experiment in you biological model system (for example control vs. treated or normal vs. disease). You can learn much more about the subject at: http://normalisation.gene-quantification.info/. Click on microRNA on the panel on the left and click on microRNA normalization link at the top of the microRNA page.
    • Why are the PAP and RT reactions not combined into a single reaction?
      A combined poly(A)-tailing and reverse transcription reactions means compromising optimal assay conditions for both steps and reduces the flexibility of the system to accommodate different end user applications. For example, the PAP reaction can be adjusted and scaled to accommodate a wide range of RNA inputs. When using less than 100 ng of total RNA the PAP reaction can be shortened to 20 minutes and/or less PAP enzyme can be used in the reaction. When using more than 1 ug of total RNA the PAP reaction can be scaled up and stored for later use into multiple RT reactions. The specificity of some microRNA assays can be increased by increasing the temperature of the cDNA synthesis reaction from 42 ˚C to 45 ˚C or higher which is good for RT but not so good for PAP. Combining the two reactions does not permit a no-poly(A) polymerase control which is a critical measurement of microRNA assay background signal and allows for detection of false-positive signals. In addition, the poly(A) polymerase would have the potential to tail the oligo dT adapter primer interfering with specificity of the cDNA synthesis reaction.
    • What are the -3p and -5p designations on each microRNA?
      Previously the mature microRNAs were referred to as major miRs and minor miRs (according to their relative abundance in specific tissues) with the minor miRs being designated with an asterisk. The nomenclature at miRBase has now changed such that for each precursor microRNA there are potentially two mature microRNAs designated with a -5p and -3p which refer to the position (5-prime arm or 3-prime arm) that the mature microRNAs occupy within the precursor stem-loop structure. On the PerfeCta microRNA Assay website click on the links for both the -5p and -3p microRNAs. In red text there is a reference to the former miRBase IDs. There is also a link to the miRBase Entry (blue button) where you can cross-check all of the information.
    • What should I do if I see a split cluster on either axis?
      This usually occurs if an alternate SNP site is present in the template, in the region complementary to the SNP-IT primer. This potential single base mismatch in some of the samples, at the alternate SNP site, may cause inefficient SNP-IT primer/template hybridization. Even though the extension step occurs, the signal is weaker in these samples and hence will show up as a distinct cluster in the scatter plot. This can be overcome by redesigning the SNP-IT for the opposite strand and on the other side of the SNP, so that the alternate SNP site is avoided altogether at the SNP-IT annealing step.
    • Should I be concerned if I observe three clusters in the scatter plot but one of them seems to be shifting to the other or are very close to each other?
      The observation is usually due to template dependent noise. This happens when the SNP-IT primer anneals to more than one site on the PCR template, other than its intended location (immediately adjacent to the SNP of interest). This phenomenon leads to multiple extensions occurring at different sites and often produces a significant level of background in the SNP-IT assay. This is commonly observed as a shift towards heterozygotes in one or more of the genotype clusters. Since this is template specific, it is usually best to choose an alternate design for the assay primers.
    • What should I do if my homozygous samples controls look like heterozygotes in the assay?
      The observation is usually due to template dependent noise. This happens when the SNP-IT primer anneals to more than one site on the PCR template, other than its intended location (immediately adjacent to the SNP of interest). This phenomenon leads to multiple extensions occurring at different sites and often produces a significant level of background in the SNP-IT assay. This is commonly observed as a shift towards heterozygotes in one or more of the genotype clusters. Since this is template specific, it is usually best to choose an alternate design for the assay primers.
    • How much of the first strand reaction should I add to the PCR?
      The volume will depend on the starting amount of RNA used for first-strand synthesis, and the abundance of the target gene. We recommend starting with 10% of the first-strand reaction. More than 10% may inhibit the PCR.
    • How do I eliminate non-specific bands in PCR?
      Here are some suggestions for optimizing your PCR under such conditions: - Make sure primers don't have complementary sequences at the 3' ends - Optimize the annealing step by increasing the temperature in 2-5C increments, and minimizing the annealing time. You can try higher annealing temperatures in the first few cycles, and lower annealing temperatures in the subsequent cycles. - Try hot-start protocols - Optimize the magnesium concentration for each template and primer combination - To minimize chances of amplifying contaminating DNA, use aerosol-resistant tips and UDG
    • What is the control date? (expiration Date)
      The control date is not the expiration date, but rather the date through which we guarantee performance of the product. If stored under the recommended conditions, the product will maintain performance through the date printed on the label.
    • One-step versus Two-step RT-PCR
      One-Step RT-PCR allows easier processing of large numbers of samples, and helps minimize carry-over contamination since tubes are not opened between cDNA synthesis and amplification. By amplifying the entire cDNA sample, one-step RT-PCR can provide greater sensitivity-down to 0.01 pg total RNA. You can only use gene specific primers with these kits. Two-Step RT-PCR is useful for detecting multiple messages from a single RNA sample. You’ll get greater flexibility when choosing polymerase and primers than with one-step RT-PCR systems. When performing two-step RT-PCR you have the option of using either oligo(dT), random hexamers, or gene-specific primers, and then performing PCR in combination with either AccuStart Taq DNA Polymerase, or your choice of other PCR enzymes.
    • What controls should be run, no-PAP, no-RT or both and why?
      When the Ct values are high (approaching 30) a no-PAP control can be used to add confidence in the results. If there is a significant difference between the plus-PAP and no-PAP reactions the results can be considered real. The no-RT control should always be negative. The kit comes with 20% extra 5x PAP reaction buffer and cDNA mix to accommodate the use of controls.
    • Is the use of UNG necessary for performing reverse transcription reactions?
      No. It is not recommended to use UNG when performing reverse transcription. When using a dNTP mix with dUTP in a RT reaction, uracil will be incorporated into the cDNA generated from your RNA template. UNG (uracil N-glycosylase) is capable of cleaving single- or double stranded DNA containing dUTP sequences. Therefore, use of UNG during a reverse transcription step will cleave the dU containing cDNA and result in significantly lower amplification or absence of amplification.
    • I am using Uracil N-glycosylase (UNG) and dUTP in my PCR reactions and would like to use the PCR product in a post-PCR application. Does the dUTP affect my ability to hybridize, sequence, clone, or digest the PCR product?
      Uracyl residues are roughly equivalent to dT-containing PCR products as hybridization targets, if long fragments (>200bases) are used. With very short fragments (<30bases), hybridization of dU containing templates will require lower temperatures depending on the dU content of DNA. Uracil residues serve in an equivalent manner as dT-containing PCR products as templates for dideoxy-terminated sequencing reactions. Uracyl residues are equivalent to dT-containing PCR products if transferred into UNG-minus bacterial hosts as targets for direct cloning. The recognition of dU-containing DNA by restriction endonucleases has been studied. Depending on the specific endonuclease, there may be no effect of the substitution of dU for dT on enzymatic activity (e.g., EcoR1 and BamH1), or the dU-containing DNA is cleaved more slowly than dT-containing DNA (e.g., Hpa1, HindII, and HindIII). For other endonucleases the effect of substituting dU for dT on enzyme activity will need to be examined empirically on an individual enzyme basis.
    • What is UNG (Uracil N-glycosylase)?
      UNG (Uracil N-glycosylase) is an enzyme used in a powerful method for the elimination of carryover PCR product. This method modifies the PCR products such that the products from previous PCR amplifications will be digested by UNG prior to initiation of amplification. During amplification dUTP is substituted for dTTP resulting in dUTP containing products. UNG is active on single and double stranded dUTP containing DNA. A short pre-PCR incubation step in subsequent reactions will allow the UNG to digest any dUTP containing DNA. Since UNG is active on single and double stranded dUTP containing DNA, the procedure should work on dU-containing PCR products from standard or asymmetric PCR amplifications. Uracil ribonucleotide residues in RNA, novel DNA containing dTTP or cDNA containing dTTP are not suitable substrates for UNG. This method is best put in place prior to the appearance of contamination problem, because it is effective only against contamination with dUTP labeled PCR products.
    • Purpose of the 25C incubation step when using Q-Script RT and Rnase Inhibitor mix
      The purpose of the 25 C incubation step when using random hexamers is to allow annealing and extention of random primers. Since the primers are short, a lower temperature is required. Omission of this step will result in inefficient cDNA synthesis.
    • Inactivation of reverse transcriptases: protocol.
      The enzymes can be inactivated by adding a chelating agent such as EDTA. They should be heated to 85°C for 5 minutes for complete inactivation.
    • M-MLV RT: Storage & Stability
      MMLV RT in the Q-Script RT and Rnase Inhibitor mix is stable up to 2 years when stored at -20°C in a non-frost-free freezer. Enzymes may remain at 4°C for up to 48 hours without loss of activity
    • What is the highest temperature that a reverse trascriptase can be used?
      The optimal temperature for MMLV is 42 C. Therefore, for optimal results, we recommend carrying out cDNA synthesis reactions at 42°C. Only in rare cases, such as One-Step qRT-PCR, where shorter and more specific RNA regions are transcribed, may it be effective to raise the temperature to 48° although a slight reduction in RT activity and half-life may occur at these temperatures. Discuss 1 step Kit temp. 45-50 and 2step kit protocols
    • Mw and Size of Taq Polymerase
      Taq DNA Polymerase is an 832 amino acid, single subunit enzyme with a MW of 94,000.
    • Optimal pH for Taq polymerase
      Taq polymerase is active from pH 7.5-9.5. The unit assay is performed at pH 9.3 in TAPs buffer.
    • Extension rate of Taq
      Taq has been reported to have an extension rate of 35-100 nt/sec at 75°C. For further information, see Wittwer (1991) BioTechniques 10(1), 76. It should be noted that the extention rate will vary depending on the conditions in which the enzyme is being used.
    • Is a probe assay more sensitive than a SYBR® Green I assay?
      A probe assay and a SYBR® Green I assay can be equally sensitive. In cases of difficult to optimize PCRs the SYBR® Green I assay might be less beneficial as it shows the total fluorescent signal of primer dimers, aspecific product and wanted product.
    • What is the advantage of working with a probe system?
      A probe system is always specific (except Amplifluor™ probes) and therefore does only detect the gene of interest. If you have a difficult to optimize PCR it will not show you any primer dimers or aspecific products. With a probe system it is also possible to distinguish between similar sequences with small differences like SNPs or mutations. In general, probe assays need less optimisation than SYBR® Green I assays.
    • What is the advantage of working with SYBR® Green I?
      SYBR® Green I is an inexpensive, universal dye which binds to all dsDNA. It can be easily used in combination with a simple primer pair to detect PCR products in Real-Time. This dye is mainly very attractive for researchers analysis lots of different genes. However it is important to do a good primer design to avoid primer dimers, which will also be detected by SYBR® Green I.
    • What is the difference in sensitivity between TaqMan® chemistry vs. SYBR® Green reagent chemistry?
      Sensitivity is equivalent when using TaqMan® chemistry and SYBR® Green reagent chemistry. Since a fluorescent signal is generated by a sequence specific TaqMan® probe, users might think a TaqMan® assay is more sensitive than a SYBR® Green reagent assay. This is not always true. A poorly designed TaqMan® assay could theoretically be less specific than a well-designed SYBR® Green reagent assay. The potential for detection of primer dimers and non-specific products using SYBR® Green reagent chemistry may result in loss of sensitivity when attempting to quantitate lower copy numbers.
    • What is the concentration of my primers and TaqMan probe to be used with Taqman assays?
      Optimal results may require titration of primer concentration between 100 and 900 nM. A final concentration of 300 nM each primer and 100 to 250 nM probe is effective for most applications. However, increasing the concentration of the primer that initiates synthesis of the target strand that is complementary to the probe can improve fluorescent signal for some primer/probe systems.
    • How should I store my cDNA?
      The cDNA can be diluted in low EDTA TE (10 mM Tris-HCl pH 8, 0.1 mM EDTA) or water and stored at 4 C or at -20 C.
    • How much cDNA should be used in each qPCR reaction?
      You can use from 10 ng down to 0.1 pg of cDNA in each qPCR reaction. The kit provides maximum flexibility with regards to the amount of starting RNA and the amount of cDNA used in the qPCR. The microRNA cDNA can be diluted appropriately to accommodate the amount of total RNA used in the cDNA synthesis reaction and the relative abundance of the microRNAs of interest. We recommend starting with 1 ng of cDNA in each qPCR. If an individual microRNA is relatively abundant then 0.1 ng may work fine. If the microRNA is rare or absent you can add up to 10 ng of cDNA to the qPCR reaction. In this case we recommend comparing your results to a no-poly(A) polymerase reaction. A significant difference between reactions with and without poly(A) polymerase will help determine if the sample is positive or negative for the microRNA of interest. Three examples are provided below: For abundant microRNAs where total RNA sample is limiting: • 20 ng of total RNA in a 20 uL cDNA synthesis reaction = 1 ng /uL • Dilute with TE (10 mM Tris-HCl pH 8.0, 0.1 mM EDTA) to 0.02 ng/uL (1/50 dilution) • Add 5 uL (0.1 ng) to a 20 uL qPCR • 200 total qPCRs For rare microRNAs: • 200 ng of total RNA in a 20 uL cDNA synthesis reaction = 10 ng/uL • Dilute with TE (10 mM Tris-HCl pH 8.0, 0.1 mM EDTA) to 2 ng/uL (1/2.5 dilution) • Add 5 uL (10 ng) to a 20 uL qPCR • 20 total qPCRs For profiling experiments: • 1000 ng total RNA in 20 uL cDNA synthesis reaction = 50 ng/uL • Dilute with TE (10 mM Tris-HCl pH 8.0, 0.1 mM EDTA) to 0.2 ng/uL (1/250 dilution) • Add 5 uL (1 ng) to a 20 uL qPCR • 1000 total qPCRs
    • What is the function of the antibody in AccuStart Taq Polymerase? How does this contribute to hot start PCR?
      AccuStart Taq DNA Polymerase is recombinant Taq DNA polymerase complexed with proprietary antibodies that inhibit polymerase activity. Due to specific binding of the antibodies, the activity of Taq DNA polymerase is blocked at ambient temperatures. Therefore, AccuStart Taq Polymerase remains inactive during reaction assembly and initial temperature ramp up. Antibodies are inactivated at the initial PCR denaturation step and release fully active Taq DNA Polymerase. This process provides an automatic hot start and improves PCR specificity, sensitivity and yield significantly. It also allows room temperature reaction assembly for high though put applications. By increasing the effectiveness of Taq DNA polymerase through the use of this product, it is possible to reduce the optimization and handling of reaction components and improve PCR results.
    • Stability of Taq polymerase
      The AccuStart Taq Polymerase and antibody should be stable a minimum of 18 months if stored properly at -20C in a non frost free freezer.
    • Components of Taq buffer
      The Accustart Taq PCR Buffer is supplied as a 10X concentrate and should be diluted 1:10 (1 part buffer + 9 parts other components = 10 parts final reaction volume). Buffer Composition (10X): 200 mM Tris-HCl (pH 8.4), 500 mM KCl. The Taq PCR buffer does not contain Magnesium Chloride. This is provided in a separate tube as 50 mM Magnesium Chloride
    • Units of AccuStart Taq DNA polymerase to be used in PCR
      1-1.5 units per 50 ul reaction are sufficient for most applications, but in some instances it may be necessary to use more enzyme.
    • DMSO inhibition of Taq DNA polymerase
      Taq DNA polymerase is inhibited 47% at a DMSO concentration of 10%. 10% DMSO is used in PCR or cycle sequencing reactions of GC rich DNA in the presence of 2X the amount of Taq DNA polymerase (see Sun, (1993) BioTechniques)
    • Does Taq DNA polymerase have RT activity
      Taq DNA Polymerase has some reverse transcriptase (RT) activity at 68-78°C. However, this activity is negligible under ordinary PCR conditions. We don’t recommend using Taq Polymerase as a reverse transcriptase.
    • Benefits of AccuStart Taq DNA Polymerase compared to regular Taq
      AccuStart Taq DNA Polymerase is a recombinant Taq DNA polymerase preparation which contains monoclonal antibodies that bind to the polymerase and keep it inactive before PCR thermal cycling. It allows for automatic hot start PCR, without extra work by the scientist:  - Room temperature reaction assembly.  - Broader optimal Magnesium concentration.  - Less primer optimization. Upon heat activation (1 minute at 94ºC), the antibodies denature irreversibly, releasing fully active Taq DNA polymerase. Non-specific extension of primers at low temperatures is a common cause of artifacts and poor sensitivity in PCR. The AccuStart automatic hot-start enables specific and efficient primer extension in the PCR process with the added convenience of room temperature reaction assembly. Activated AccuStart Taq DNA polymerase possesses 5’→3’ DNA polymerase activity and a double-strand specific 5’→3’ exonuclease. The polymerase does not have 3’-exonuclease activity and is free of any contaminating endo or exonuclease activities. One unit is defined as the amount of enzyme that will incorporate 10 nmol of dNTP into acid-insoluble material in 30 minutes at 74°C. AccuStart Taq DNA polymerase is stable for 2 years when stored in a constant temperature freezer at 20ºC.
    • Does AccuStart Taq DNA Polymerase remain in an active state once it is activated?
      Yes, once activated, AccuStart Taq DNA Polymerase remains active. Lowering the temperature will not inactivate AccuStart Taq DNA Polymerase.
    • Unit definitions for AccuStart Taq DNA Polymerase
      One unit (U) of enzyme is defined as the amount that will incorporate 10nmoles of dNTPs into acid insoluble material per 30 minutes in a 10-minute incubation at 74 oC under the analysis conditions provided in the product insert. AccuStart Taq DNA Polymerase is premixed with anti Taq Antibodies. It can be activated by heating at 95C for 1-3 minutes.
    • Does AccuStart Taq DNA Polymerase have proofreading activity?
      No, AccuStart Taq DNA Polymerase does not have proofreading activity. Fidelity of this Polymerase in PCR amplifications may be improved, by: 1. Decreasing the final concentration of each nucleotide to 40-50 uM. 2. Using the lowest MgCl2 concentration possible. 3. Using less enzyme. 4. Decreasing extension times. 5. Using the highest annealing temperature possible. 6. Using as few cycles as possible.
    • What is the activation time for AccuStart™ Taq DNA Polymerase and AccuFast™ Taq DNA Polymerase ?
      "The recommended activation time depends on which Supermix is being used: Activation Conditions for AccuStart™ Taq DNA Polymerase in: PerfeCTa qPCR Supermixes 1-2 min, 95C PerfeCTa SYBR Green Supermixes 1-2 min, 95C Activation Conditions for AccuFast™ Taq DNA Polymerase in: PerfeCTa qPCR FastMixes 20 sec, 95C PerfeCTa SYBR Green FastMixes 20 sec, 95C

Publications

  • PCR
    • Real-Time Quantitative PCR
      • SYBR Green Detection
        • DNA
          A STUDY OF THE EFFEC Y OF THE EFFECT OF PH T OF PHYSIOLOGICAL STRESSORS ON OGICAL STRESSORS ON HYPOTHALAMIC REGUL AMIC REGULATION OF REPRODUC TION OF REPRODUCTION USING AN IN TION USING AN IN VITRO SYSTEM
          Lisa L. Amelse - 2022
          Abstract
          Stressors have a negative impact on reproductive efficiency in humans and other animals, which has an economic cost due to infertility treatments for humans and reduced income for food producers. We wished to determine the molecular pathways by which metabolic disturbances and low-level inflammation impact the hypothalamic pituitary gonadal (HPG) axis using an in vitro model. To this end, we used the GT1-7 cell line, an immortalized line expressing the Kiss1R receptor that responds to kisspeptin stimulation with the release of GnRH to assess the impact of stressors on the GnRH-releasing cells. Additionally, we used the KTaV-3 and KTaR-1 cell lines, immortalize lines derived from the rodent anteroventral periventricular and arcuate nuclei, respectively, to assess the impact of stressors on kisspeptin-producing cells. We modeled metabolic disease and negative energy balance by exposing cells to betahydroxybutyric acid (BHB) and inflammation by exposure to tumor necrosis factor alpha (TNFα [alpha]). We determined that exposure to BHB significantly increased the intrinsic production of GnRH by GT1-7 cells, but that there were no additional changes in the expression of GnRH mRNA or release of GnRH protein. Additionally, there were no significant changes in calcium signaling or in the phosphorylation of ERK1/2, suggesting that the direct effect of stressors does not impact the GnRH-producing cells of the hypothalamus. Exposure to stressors in culture did not change the expression of kiss mRNA in KTaV-3 cells upon exposure to estradiol. However, KTaV-1 cells exhibited a significantly decreased expression of kiss1 mRNA and kiss1 protein release upon exposure to both BHB and tumor necrosis factor alpha. There was also a reduction in the expression of neurokinin B (nkb) mRNA under these conditions, suggesting that the impact of stressors on the HPG axis may be acting through the suppression of signaling in the arcuate nucleus. Disruption of neurokinin B and kisspeptin expression in the arcuate nucleus could impact the production of tonic levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH), resulting in a deficiency in follicle production and oocyte maturation.
          Mitochondrial complex I dysfunction alters the balance of soluble and membrane-bound TNF during chronic experimental colitis
          Ainize Peña-Cearra - 2022
          Abstract
          Inflammatory bowel disease (IBD) is a complex, chronic, relapsing and heterogeneous disease induced by environmental, genomic, microbial and immunological factors. MCJ is a mitochondrial protein that regulates the metabolic status of macrophages and their response to translocated bacteria. Previously, an acute murine model of DSS-induced colitis showed increased disease severity due to MCJ deficiency. Unexpectedly, we now show that MCJ-deficient mice have augmented tumor necrosis factor α converting enzyme (TACE) activity in the context of chronic inflammation. This adaptative change likely affects the balance between soluble and transmembrane TNF and supports the association of the soluble form and a milder phenotype. Interestingly, the general shifts in microbial composition previously observed during acute inflammation were absent in the chronic model of inflammation in MCJ-deficient mice. However, the lack of the mitochondrial protein resulted in increased alpha diversity and the reduction in critical microbial members associated with inflammation, such as Ruminococcus gnavus, which could be associated with TACE activity. These results provide evidence of the dynamic metabolic adaptation of the colon tissue to chronic inflammatory changes mediated by the control of mitochondrial function.
      • Probe-based Detection
        A telomere-to-telomere gap-free reference genome of watermelon and its mutation library provide important resources for gene discovery and breeding
        Yun Deng - 2022
        Abstract
        Watermelon, Citrullus lanatus, is the world’s third largest fruity crop. Reference genomes with gaps and narrow genetic base hinder functional genomics and genetic improvement of watermelon. Here, we report the assembly of a telomere-to-telomere (T2T) gap-free genome of the elite watermelon inbred G42 by incorporating the high-coverage and accurate long-read sequence data with multiple assembly strategies. All 11 chromosomes have been assembled into single contig pseudomolecules without gap, representing the highest completeness and assembly quality till now. The G42 reference genome contained a total length of 369,321,829 bp and 24,205 predicted protein-coding genes, with all 22 telomeres and 11 centromeres characterized. Over 200,000 M1 seeds from inbred G42 were generated using pollen EMS mutagenesis. In a sampling pool, 48 monogenic phenotypic mutations, selected from 223 M1 and 78 M2 mutants with morphological changes, were confirmed. The average density of mutation is 1 SNP/1.69 Mb and 1 indel/4.55 Mb per M1 plant, and 1 SNP/1.08 Mb and 1 indel/6.25 Mb per M2 plant. Taking advantage of the gap-free G42 genome, 8,039 mutations from the 32 plants sampled from M1 and M2 families were identified with 100% accuracy, whereas only 25% of the randomly selected mutations identified using 97103v2 reference genome could be confirmed. Using this library and the gap-free genome, two genes responsible for elongated fruit shape and male sterility (ClMS1) were identified, both being caused by a single base change from G to A. The validated gap-free genome and its EMS mutation library provide invaluable resources for functional genomics and genetic improvement of watermelon.
        TIRAP/Mal Positively Regulates TLR8‐Mediated Signaling via IRF5 in Human Cells
        Kaja Elisabeth Nilsen - 2022
        Abstract
        Toll‐like receptor 8 (TLR8) recognizes single‐stranded RNA of viral and bacterial origin as well as mediates the secretion of pro‐inflammatory cytokines and type I interferons by human monocytes and macrophages. TLR8, as other endosomal TLRs, utilizes the MyD88 adaptor protein for initiation of signaling from endosomes. Here, we addressed the potential role of the Toll‐inter‐ leukin 1 receptor domain‐containing adaptor protein (TIRAP) in the regulation of TLR8 signaling in human primary monocyte‐derived macrophages (MDMs). To accomplish this, we performed TIRAP gene silencing, followed by the stimulation of cells with synthetic ligands or live bacteria. Cytokine‐gene expression and secretion were analyzed by quantitative PCR or Bioplex assays, re‐ spectively, while nuclear translocation of transcription factors was addressed by immunofluores‐ cence and imaging, as well as by cell fractionation and immunoblotting. Immunoprecipitation and Akt inhibitors were also used to dissect the signaling mechanisms. Overall, we show that TIRAP is recruited to the TLR8 Myddosome signaling complex, where TIRAP contributes to Akt‐kinase acti‐ vation and the nuclear translocation of interferon regulatory factor 5 (IRF5). Recruitment of TIRAP to the TLR8 signaling complex promotes the expression and secretion of the IRF5‐dependent cyto‐ kines IFNβ and IL‐12p70 as well as, to a lesser degree, TNF. These findings reveal a new and un‐ conventional role of TIRAP in innate immune defense
        Echovirus 9 genetic diversity detected in whole-capsid genome sequences obtained directly from clinical specimens using next generation sequencing
        Erika Bujaki - 2022
        Abstract
        Echovirus 9 (E9) has been detected in an increased number of symptomatic patient samples received by the National Enterovirus Reference Laboratory in Hungary during 2018 compared to previously reported years. Formerly identified E9 viruses from different specimen types detected from patients of various ages and showing differing clinical signs were chosen for the detailed analysis of genetic relationships and potential variations within the viral populations. We used next generation sequencing (NGS) analysis of 3,900 nucleotide long amplicons covering the entire capsid coding region of the viral genome without isolation, directly from clinical samples. Compared to the E9 reference strain, the viruses showed about 79% nucleotide and around 93% amino acid sequence similarity. The four new viral genome sequences had 1-20 nucleotide differences between them also resulting in 6 amino acid variances in the coding region, including 3 in the structural VP1 capsid protein. One virus from a patient with hand, foot, and mouth disease had two amino acid changes in the VP1 capsid protein. An amino acid difference was also detected in the non-structural 2C gene of one virus sequenced from a throat swab sample from a patient with meningitis, compared to the faecal specimen taken two days later. Two amino acid changes, one in the capsid protein, were found between faecal samples of meningitis patients of different ages. Sequencing the whole capsid genome revealed several nucleotide and amino acid differences between E9 virus strains detected in Hungary in 2018.
        Novel Roles of the Nipah Virus Attachment Glycoprotein and Its Mobility in Early and Late Membrane Fusion Steps
        Victoria Ortega - 2022
        Abstract
        The Paramyxoviridae family comprises important pathogens that include measles (MeV), mumps, parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). Paramyxoviral entry into cells requires viral-cell membrane fusion, and formation of paramyxoviral pathognomonic syncytia requires cell-cell membrane fusion. Both events are coordinated by intricate interactions between the tetrameric attachment (G/H/HN) and trimeric fusion (F) glycoproteins. We report that receptor binding induces conformational changes in NiV G that expose its stalk domain, which triggers F through a cascade from prefusion to prehairpin intermediate (PHI) to postfusion conformations, executing membrane fusion. To decipher how the NiV G stalk may trigger F, we introduced cysteines along the G stalk to increase tetrameric strength and restrict stalk mobility. While most point mutants displayed near-wild-type levels of cell surface expression and receptor binding, most yielded increased NiV G oligomeric strength, and showed remarkably strong defects in syncytium formation. Furthermore, most of these mutants displayed stronger F/G interactions and significant defects in their ability to trigger F, indicating that NiV G stalk mobility is key to proper F triggering via moderate G/F interactions. Also remarkably, a mutant capable of triggering F and of fusion pore formation yielded little syncytium formation, implicating G or G/F interactions in a late step occurring post fusion pore formation, such as the extensive fusion pore expansion required for syncytium formation. This study uncovers novel mechanisms by which the G stalk and its oligomerization/mobility affect G/F interactions, the triggering of F, and a late fusion pore expansion step—exciting novel findings for paramyxoviral attachment glycoproteins. IMPORTANCE The important Paramyxoviridae family includes measles, mumps, human parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). The deadly emerging NiV can cause neurologic and respiratory symptoms in humans with a .60% mortality rate. NiV has two surface proteins, the receptor binding protein (G) and fusion (F) glycoproteins. They mediate the required membrane fusion during viral entry into host cells and during syncytium formation, a hallmark of paramyxoviral and NiV infections. We previously discovered that the G stalk domain is important for triggering F (via largely unknown mechanisms) to induce membrane fusion. Here, we uncovered new roles and mechanisms by which the G stalk and its mobility modulate the triggering of F and also unexpectedly affect a very late step in membrane fusion, namely fusion pore expansion. Importantly, these novel findings may extend to other paramyxoviruses, offering new potential targets for therapeutic interventions.
        Occurrence of Naegleria fowleri and faecal indicators in sediments from Lake Pontchartrain, Louisiana
        Shalina A. Shahin - 2022
        Abstract
        The occurrence of amoeba, Naegleria fowleri, in sediment samples from Lake Pontchartrain in Louisiana was investigated. This amoeba is pathogenic and can cause primary amoebic meningoencephalitis. In this study, quantitative polymerase chain reaction methods were used to test for the prevalence of Naegleria fowleri, HF183, and E. coli. N. fowleri was detected in 51.25% of our sediment samples. Illumina sequencing of sediment samples revealed ten different phyla, with Cyanobacteria being the most predominant at sites that generally presented with the highest median N. fowleri concentrations. N. fowleri was however strongly negatively correlated with HF183 (r = −0.859, p < 0.001). Whenever sediment E. coli concentrations were below 1.54 Log GC/g, there was only a 37.5% chance that N. fowleri would be detected in the same sample. When sediment E. coli concentrations exceeded 2.77 Log GC/g, the chances of detecting N. fowleri in the same sample increased to 90%, potentially suggesting predatory activity by the amoeba. The effect of temperature was observed to be different in relation to observed N. fowleri concentrations and detection rates. Although sediment samples collected during periods of higher temperatures had significantly lower mean N. fowleri concentrations (2.7 Log GC/g) compared to those collected at lower temperatures (3.7 Log GC/g, t(39) = 4.167, p < 0.001), higher N. fowleri detection rates in the overall samples were observed at higher temperatures (>19.1 °C) than at lower temperatures (<19.1 °C).
        Point-of-Care Platform for Rapid Multiplexed Detection of SARS-CoV-2 Variants and Respiratory Pathogens
        Alexander Y. Trick - 2022
        Abstract
        The rise of highly transmissible SARS-CoV-2 variants brings new challenges and concerns with vaccine efficacy, diagnostic sensitivity, and public health responses to end the pandemic. Widespread detection of variants is critical to inform policy decisions to mitigate further spread, and postpandemic multiplexed screening of respiratory viruses will be necessary to properly manage patients presenting with similar respiratory symptoms. In this work, a portable, magnetofluidic cartridge platform for automated polymerase chain reaction testing in <30 min is developed. Cartridges are designed for multiplexed detection of SARS-CoV-2 with either identification of variant mutations or screening for Influenza A and B. Moreover, the platform can perform identification of B.1.1.7 and B.1.351 variants and the multiplexed SARS-CoV-2/Influenza assay using archived clinical nasopharyngeal swab eluates and saliva samples. This work illustrates a path toward affordable and immediate testing with potential to aid surveillance of viral variants and inform patient treatment.
        Specific inhibition of the NLRP3 inflammasome suppresses immune overactivation and alleviates COVID-19 like pathology in mice
        Jianxiong Zeng - 2022
        Abstract
        Background The Coronavirus Disease 2019 (COVID-19) pandemic has been a great threat to global public health since 2020. Although the advance on vaccine development has been largely achieved, a strategy to alleviate immune overactivation in severe COVID-19 patients is still needed. The NLRP3 inflammasome is activated upon SARS-CoV-2 infection and associated with COVID-19 severity. However, the processes by which the NLRP3 inflammasome is involved in COVID-19 disease remain unclear. Methods We infected THP-1 derived macrophages, NLRP3 knockout mice, and human ACE2 transgenic mice with live SARS-CoV-2 in Biosafety Level 3 (BSL-3) laboratory. We performed quantitative real-time PCR for targeted viral or host genes from SARS-CoV-2 infected mouse tissues, conducted histological or immunofluorescence analysis in SARS-CoV-2 infected mouse tissues. We also injected intranasally AAV-hACE2 or intraperitoneally NLRP3 inflammasome inhibitor MCC950 before SARS-CoV-2 infection in mice as indicated. Findings We have provided multiple lines of evidence that the NLRP3 inflammasome plays an important role in the host immune response to SARS-CoV-2 invasion of the lungs. Inhibition of the NLRP3 inflammasome attenuated the release of COVID-19 related pro-inflammatory cytokines in cell cultures and mice. The severe pathology induced by SARS-CoV-2 in lung tissues was reduced in Nlrp3−/− mice compared to wild-type C57BL/6 mice. Finally, specific inhibition of the NLRP3 inflammasome by MCC950 alleviated excessive lung inflammation and thus COVID-19 like pathology in human ACE2 transgenic mice. Interpretation Inflammatory activation induced by SARS-CoV-2 is an important stimulator of COVID-19 related immunopathology. Targeting the NLRP3 inflammasome is a promising immune intervention against severe COVID-19 disease.
        A Sensitive, Portable Microfluidic Device for SARS-CoV-2 Detection from Self-Collected Saliva
        Jianing Yang - 2021
        Abstract
        Since the outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in December 2019, the spread of SARS-CoV2 infection has been escalating rapidly around the world. In order to provide more timely access to medical intervention, including diagnostic tests and medical treatment, the FDA authorized multiple test protocols for diagnostic tests from nasopharyngeal swab, saliva, urine, bronchoalveolar lavage and fecal samples. The traditional diagnostic tests for this novel coronavirus 2019 require standard processes of viral RNA isolation, reverse transcription of RNA to cDNA, then real-time quantitative PCR with the RNA templates extracted from the patient samples. Recently, many reports have demonstrated a direct detection of SARS-Co-V2 genomic material from saliva samples without any RNA isolation step. To make the rapid detection of SARS-Co-V2 infection more accessible, a point-of-care type device was developed for SARS-CoV-2 detection. Herein, we report a portable microfluidic-based integrated detectionanalysis system for SARS-CoV-2 nucleic acids detection directly from saliva samples. The saliva cartridge is self-contained and capable of microfluidic evaluation of saliva, from heating, mixing with the primers to multiplex real-time quantitative polymerase chain reaction, detecting SARSCoV- 2 with different primer sets and internal control. The approach has a detection sensitivity of 1000 copies/mL of SARS-CoV-2 RNA or virus, with consistency and automation, from saliva sample-in to result-out.
        RIPK1 or RIPK3 deletion prevents progressive neuronal cell death and improves memory function after traumatic brain injury
        Antonia Clarissa Wehn - 2021
        Abstract
        Traumatic brain injury (TBI) causes acute and subacute tissue damage, but is also associated with chronic inflammation and progressive loss of brain tissue months and years after the initial event. The trigger and the subsequent molecular mechanisms causing chronic brain injury after TBI are not well understood. The aim of the current study was therefore to investigate the hypothesis that necroptosis, a form a programmed cell death mediated by the interaction of Receptor Interacting Protein Kinases (RIPK) 1 and 3, is involved in this process. Neuron-specific RIPK1- or RIPK3-deficient mice and their wild-type littermates were subjected to experimental TBI by controlled cortical impact. Posttraumatic brain damage and functional outcome were assessed longitudinally by repetitive magnetic resonance imaging (MRI) and behavioral tests (beam walk, Barnes maze, and tail suspension), respectively, for up to three months after injury. Thereafter, brains were investigated by immunohistochemistry for the necroptotic marker phosphorylated mixed lineage kinase like protein(pMLKL) and activation of astrocytes and microglia. WT mice showed progressive chronic brain damage in cortex and hippocampus and increased levels of pMLKL after TBI. Chronic brain damage occurred almost exclusively in areas with iron deposits and was significantly reduced in RIPK1- or RIPK3-deficient mice by up to 80%. Neuroprotection was accompanied by a reduction of astrocyte and microglia activation and improved memory function. The data of the current study suggest that progressive chronic brain damage and cognitive decline after TBI depend on the expression of RIPK1/3 in neurons. Hence, inhibition of necroptosis signaling may represent a novel therapeutic target for the prevention of chronic post-traumatic brain damage.
        Autologous Transplantation of Skin-Derived Precursor Cells in a Porcine Model
        Anne-Laure Thomas - 2020
        Abstract
        Background Hirschprung's disease is characterized by aganglionic bowel and often requires surgical resection. Cell-based therapies have been investigated as potential alternatives to restore functioning neurons. Skin-derived precursor cells (SKPs) differentiate into neural and glial cells in vitro and generate ganglion-like structures in rodents. In this report, we aimed to translate this approach into a large animal model of aganglionosis using autologous transplantation of SKPs. Methods Juvenile pigs underwent skin procurement from the shoulder and simultaneous chemical denervation of an isolated colonic segment. Skin cells were cultured in neuroglial-selective medium and labeled with fluorescent dye for later identification. The cultured SKPs were then injected into the aganglionic segments of colon, and the specimens were retrieved within seven days after transplantation. SKPs in vitro and in vivo were assessed with histologic samples for various immunofluorescent markers of multipotency and differentiation. SKPs from the time of harvest were compared to those at the time of injection using PCR. Results Prior to transplantation, 72% of SKPs stained positive for nestin and S100b, markers of neural and glial precursor cells of neural crest origin, respectively. Markers of differentiated neurons and gliocytes, TUJ1 and GFAP, were detected in 47% of cultured SKPs. After transplantation, SKPs were identified in both myenteric and submucosal plexuses of the treated colon. Nestin co-expression was detected in the SKPs within the aganglionic colon in vivo. Injected SKPs appeared to migrate and express early neuroglial differentiation markers. Conclusions Autologous SKPs implanted into aganglionic bowel demonstrated immunophenotypes of neuroglial progenitors. Our results suggest that autologous SKPs may be potentially useful for cell-based therapy for patients with enteric nervous system disorders. Type of Study Basic science.
        Investigation of an outbreak caused by antibiotic‐susceptible Klebsiella oxytoca in a neonatal intensive care unit in Norway
        Torunn Gresdal Ronning - 2019
        Abstract
        Aim Klebsiella spp. have been stated to be the most frequent cause of neonatal intensive care unit (NICU) outbreaks. We report an outbreak of Klebsiella oxytoca in a NICU at a tertiary care hospital in Norway between April 2016 and April 2017. This study describes the outbreak, infection control measures undertaken and the molecular methods developed. Methods The outbreak prompted detailed epidemiological and microbial investigations, where whole‐genome sequencing (WGS) was particularly useful for both genotyping and development of two new K. oxytoca‐specific real‐time PCR assays. Routine screening of patients, as well as sampling from numerous environmental sites, was performed during the outbreak. A bundle of infection control measures was instigated to control the outbreak, among them strict cohort isolation. Results Five neonates had symptomatic infection, and 17 were found to be asymptomatically colonised. Infections varied in severity from conjunctivitis to a fatal case of pneumonia. A source of the outbreak could not be determined. Conclusion This report describes K. oxytoca as a significant pathogen in a NICU outbreak setting and highlights the importance of developing appropriate microbiological screening methods and implementing strict infection control measures to control the outbreak in a setting where the source could not be identified.
      • RNA
        Echovirus 9 genetic diversity detected in whole-capsid genome sequences obtained directly from clinical specimens using next generation sequencing
        Erika Bujaki - 2022
        Abstract
        Echovirus 9 (E9) has been detected in an increased number of symptomatic patient samples received by the National Enterovirus Reference Laboratory in Hungary during 2018 compared to previously reported years. Formerly identified E9 viruses from different specimen types detected from patients of various ages and showing differing clinical signs were chosen for the detailed analysis of genetic relationships and potential variations within the viral populations. We used next generation sequencing (NGS) analysis of 3,900 nucleotide long amplicons covering the entire capsid coding region of the viral genome without isolation, directly from clinical samples. Compared to the E9 reference strain, the viruses showed about 79% nucleotide and around 93% amino acid sequence similarity. The four new viral genome sequences had 1-20 nucleotide differences between them also resulting in 6 amino acid variances in the coding region, including 3 in the structural VP1 capsid protein. One virus from a patient with hand, foot, and mouth disease had two amino acid changes in the VP1 capsid protein. An amino acid difference was also detected in the non-structural 2C gene of one virus sequenced from a throat swab sample from a patient with meningitis, compared to the faecal specimen taken two days later. Two amino acid changes, one in the capsid protein, were found between faecal samples of meningitis patients of different ages. Sequencing the whole capsid genome revealed several nucleotide and amino acid differences between E9 virus strains detected in Hungary in 2018.
        Novel Roles of the Nipah Virus Attachment Glycoprotein and Its Mobility in Early and Late Membrane Fusion Steps
        Victoria Ortega - 2022
        Abstract
        The Paramyxoviridae family comprises important pathogens that include measles (MeV), mumps, parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). Paramyxoviral entry into cells requires viral-cell membrane fusion, and formation of paramyxoviral pathognomonic syncytia requires cell-cell membrane fusion. Both events are coordinated by intricate interactions between the tetrameric attachment (G/H/HN) and trimeric fusion (F) glycoproteins. We report that receptor binding induces conformational changes in NiV G that expose its stalk domain, which triggers F through a cascade from prefusion to prehairpin intermediate (PHI) to postfusion conformations, executing membrane fusion. To decipher how the NiV G stalk may trigger F, we introduced cysteines along the G stalk to increase tetrameric strength and restrict stalk mobility. While most point mutants displayed near-wild-type levels of cell surface expression and receptor binding, most yielded increased NiV G oligomeric strength, and showed remarkably strong defects in syncytium formation. Furthermore, most of these mutants displayed stronger F/G interactions and significant defects in their ability to trigger F, indicating that NiV G stalk mobility is key to proper F triggering via moderate G/F interactions. Also remarkably, a mutant capable of triggering F and of fusion pore formation yielded little syncytium formation, implicating G or G/F interactions in a late step occurring post fusion pore formation, such as the extensive fusion pore expansion required for syncytium formation. This study uncovers novel mechanisms by which the G stalk and its oligomerization/mobility affect G/F interactions, the triggering of F, and a late fusion pore expansion step—exciting novel findings for paramyxoviral attachment glycoproteins. IMPORTANCE The important Paramyxoviridae family includes measles, mumps, human parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). The deadly emerging NiV can cause neurologic and respiratory symptoms in humans with a .60% mortality rate. NiV has two surface proteins, the receptor binding protein (G) and fusion (F) glycoproteins. They mediate the required membrane fusion during viral entry into host cells and during syncytium formation, a hallmark of paramyxoviral and NiV infections. We previously discovered that the G stalk domain is important for triggering F (via largely unknown mechanisms) to induce membrane fusion. Here, we uncovered new roles and mechanisms by which the G stalk and its mobility modulate the triggering of F and also unexpectedly affect a very late step in membrane fusion, namely fusion pore expansion. Importantly, these novel findings may extend to other paramyxoviruses, offering new potential targets for therapeutic interventions.
        Point-of-Care Platform for Rapid Multiplexed Detection of SARS-CoV-2 Variants and Respiratory Pathogens
        Alexander Y. Trick - 2022
        Abstract
        The rise of highly transmissible SARS-CoV-2 variants brings new challenges and concerns with vaccine efficacy, diagnostic sensitivity, and public health responses to end the pandemic. Widespread detection of variants is critical to inform policy decisions to mitigate further spread, and postpandemic multiplexed screening of respiratory viruses will be necessary to properly manage patients presenting with similar respiratory symptoms. In this work, a portable, magnetofluidic cartridge platform for automated polymerase chain reaction testing in <30 min is developed. Cartridges are designed for multiplexed detection of SARS-CoV-2 with either identification of variant mutations or screening for Influenza A and B. Moreover, the platform can perform identification of B.1.1.7 and B.1.351 variants and the multiplexed SARS-CoV-2/Influenza assay using archived clinical nasopharyngeal swab eluates and saliva samples. This work illustrates a path toward affordable and immediate testing with potential to aid surveillance of viral variants and inform patient treatment.
        Specific inhibition of the NLRP3 inflammasome suppresses immune overactivation and alleviates COVID-19 like pathology in mice
        Jianxiong Zeng - 2022
        Abstract
        Background The Coronavirus Disease 2019 (COVID-19) pandemic has been a great threat to global public health since 2020. Although the advance on vaccine development has been largely achieved, a strategy to alleviate immune overactivation in severe COVID-19 patients is still needed. The NLRP3 inflammasome is activated upon SARS-CoV-2 infection and associated with COVID-19 severity. However, the processes by which the NLRP3 inflammasome is involved in COVID-19 disease remain unclear. Methods We infected THP-1 derived macrophages, NLRP3 knockout mice, and human ACE2 transgenic mice with live SARS-CoV-2 in Biosafety Level 3 (BSL-3) laboratory. We performed quantitative real-time PCR for targeted viral or host genes from SARS-CoV-2 infected mouse tissues, conducted histological or immunofluorescence analysis in SARS-CoV-2 infected mouse tissues. We also injected intranasally AAV-hACE2 or intraperitoneally NLRP3 inflammasome inhibitor MCC950 before SARS-CoV-2 infection in mice as indicated. Findings We have provided multiple lines of evidence that the NLRP3 inflammasome plays an important role in the host immune response to SARS-CoV-2 invasion of the lungs. Inhibition of the NLRP3 inflammasome attenuated the release of COVID-19 related pro-inflammatory cytokines in cell cultures and mice. The severe pathology induced by SARS-CoV-2 in lung tissues was reduced in Nlrp3−/− mice compared to wild-type C57BL/6 mice. Finally, specific inhibition of the NLRP3 inflammasome by MCC950 alleviated excessive lung inflammation and thus COVID-19 like pathology in human ACE2 transgenic mice. Interpretation Inflammatory activation induced by SARS-CoV-2 is an important stimulator of COVID-19 related immunopathology. Targeting the NLRP3 inflammasome is a promising immune intervention against severe COVID-19 disease.
        A Sensitive, Portable Microfluidic Device for SARS-CoV-2 Detection from Self-Collected Saliva
        Jianing Yang - 2021
        Abstract
        Since the outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic in December 2019, the spread of SARS-CoV2 infection has been escalating rapidly around the world. In order to provide more timely access to medical intervention, including diagnostic tests and medical treatment, the FDA authorized multiple test protocols for diagnostic tests from nasopharyngeal swab, saliva, urine, bronchoalveolar lavage and fecal samples. The traditional diagnostic tests for this novel coronavirus 2019 require standard processes of viral RNA isolation, reverse transcription of RNA to cDNA, then real-time quantitative PCR with the RNA templates extracted from the patient samples. Recently, many reports have demonstrated a direct detection of SARS-Co-V2 genomic material from saliva samples without any RNA isolation step. To make the rapid detection of SARS-Co-V2 infection more accessible, a point-of-care type device was developed for SARS-CoV-2 detection. Herein, we report a portable microfluidic-based integrated detectionanalysis system for SARS-CoV-2 nucleic acids detection directly from saliva samples. The saliva cartridge is self-contained and capable of microfluidic evaluation of saliva, from heating, mixing with the primers to multiplex real-time quantitative polymerase chain reaction, detecting SARSCoV- 2 with different primer sets and internal control. The approach has a detection sensitivity of 1000 copies/mL of SARS-CoV-2 RNA or virus, with consistency and automation, from saliva sample-in to result-out.
        RIPK1 or RIPK3 deletion prevents progressive neuronal cell death and improves memory function after traumatic brain injury
        Antonia Clarissa Wehn - 2021
        Abstract
        Traumatic brain injury (TBI) causes acute and subacute tissue damage, but is also associated with chronic inflammation and progressive loss of brain tissue months and years after the initial event. The trigger and the subsequent molecular mechanisms causing chronic brain injury after TBI are not well understood. The aim of the current study was therefore to investigate the hypothesis that necroptosis, a form a programmed cell death mediated by the interaction of Receptor Interacting Protein Kinases (RIPK) 1 and 3, is involved in this process. Neuron-specific RIPK1- or RIPK3-deficient mice and their wild-type littermates were subjected to experimental TBI by controlled cortical impact. Posttraumatic brain damage and functional outcome were assessed longitudinally by repetitive magnetic resonance imaging (MRI) and behavioral tests (beam walk, Barnes maze, and tail suspension), respectively, for up to three months after injury. Thereafter, brains were investigated by immunohistochemistry for the necroptotic marker phosphorylated mixed lineage kinase like protein(pMLKL) and activation of astrocytes and microglia. WT mice showed progressive chronic brain damage in cortex and hippocampus and increased levels of pMLKL after TBI. Chronic brain damage occurred almost exclusively in areas with iron deposits and was significantly reduced in RIPK1- or RIPK3-deficient mice by up to 80%. Neuroprotection was accompanied by a reduction of astrocyte and microglia activation and improved memory function. The data of the current study suggest that progressive chronic brain damage and cognitive decline after TBI depend on the expression of RIPK1/3 in neurons. Hence, inhibition of necroptosis signaling may represent a novel therapeutic target for the prevention of chronic post-traumatic brain damage.
        Autologous Transplantation of Skin-Derived Precursor Cells in a Porcine Model
        Anne-Laure Thomas - 2020
        Abstract
        Background Hirschprung's disease is characterized by aganglionic bowel and often requires surgical resection. Cell-based therapies have been investigated as potential alternatives to restore functioning neurons. Skin-derived precursor cells (SKPs) differentiate into neural and glial cells in vitro and generate ganglion-like structures in rodents. In this report, we aimed to translate this approach into a large animal model of aganglionosis using autologous transplantation of SKPs. Methods Juvenile pigs underwent skin procurement from the shoulder and simultaneous chemical denervation of an isolated colonic segment. Skin cells were cultured in neuroglial-selective medium and labeled with fluorescent dye for later identification. The cultured SKPs were then injected into the aganglionic segments of colon, and the specimens were retrieved within seven days after transplantation. SKPs in vitro and in vivo were assessed with histologic samples for various immunofluorescent markers of multipotency and differentiation. SKPs from the time of harvest were compared to those at the time of injection using PCR. Results Prior to transplantation, 72% of SKPs stained positive for nestin and S100b, markers of neural and glial precursor cells of neural crest origin, respectively. Markers of differentiated neurons and gliocytes, TUJ1 and GFAP, were detected in 47% of cultured SKPs. After transplantation, SKPs were identified in both myenteric and submucosal plexuses of the treated colon. Nestin co-expression was detected in the SKPs within the aganglionic colon in vivo. Injected SKPs appeared to migrate and express early neuroglial differentiation markers. Conclusions Autologous SKPs implanted into aganglionic bowel demonstrated immunophenotypes of neuroglial progenitors. Our results suggest that autologous SKPs may be potentially useful for cell-based therapy for patients with enteric nervous system disorders. Type of Study Basic science.
    • Conventional PCR
      • DNA
        Evaluation of nutrient characteristics and bacterial community in agricultural soil groups for sustainable land management
        Sumeth Wongkiew - 2022
        Abstract
        The soil bacterial community is critical for understanding biological processes in soils and is used for agricultural soil management. The understanding of microorganisms and ecology in different soil groups classified based on soil properties (e.g., minerals, soil texture, location, nitrogen, phosphorus, organic carbon and pH, among others), is limited. To suggest soil management strategies using bacterial data, we classified soils into four groups based on physical–chemical characteristics and elucidated their relationships with soil nutrient characteristics and the bacterial community in agricultural fields in Saraburi Province, Thailand. Results show that soil groups with high bacterial diversity had positive correlations with total Kjeldahl nitrogen and available phosphorus but were negatively affected by total organic carbon and pH levels. Dominant bacterial genera included Lactobacillus, Phascolarctobacterium, Prevotella, Clostridium, Gaiellales and Blautia. Significant key biomarkers were found (p < 0.05). Nutrient-rich soil groups (high available P, acidic pH) were found with genus Agromyces, while low nutrient soil groups (low available P, basic pH) were found with Hydrogenispora, Ignavibacterium and Bauldia. Based on co-occurrence networks, organic degrading bacteria functioned with other bacteria at high degrees of interconnections, suggesting organic amendment, biostimulation and biodegradation using nutrient-rich organic substrates could be used for agricultural soil improvements.
        Opposite effects of stress on effortful motivation in high and low anxiety are mediated by CRHR1 in the VTA
        Ioannis Zalachoras - 2022
        Abstract
        Individuals frequently differ in their behavioral and cognitive responses to stress. However, whether motivation is differently affected by acute stress in different individuals remains to be established. By exploiting natural variation in trait anxiety in outbred Wistar rats, we show that acute stress facilitates effort-related motivation in low anxious animals, while dampening effort in high anxious ones. This model allowed us to address the mechanisms underlying acute stress–induced differences in motivated behavior. We show that CRHR1 expression levels in dopamine neurons of the ventral tegmental area (VTA)—a neuronal type implicated in the regulation of motivation—depend on animals’ anxiety, and these differences in CRHR1 expression levels explain the divergent effects of stress on both effortful behavior and the functioning of mesolimbic DA neurons. These findings highlight CRHR1 in VTA DA neurons—whose levels vary with individuals’ anxiety—as a switching mechanism determining whether acute stress facilitates or dampens motivation.
        DNA methylation in Friedreich ataxia silences expression of frataxin isoform E
        Layne N. Rodden - 2022
        Abstract
        Epigenetic silencing in Friedreich ataxia (FRDA), induced by an expanded GAA triplet-repeat in intron 1 of the FXN gene, results in deficiency of the mitochondrial protein, frataxin. A lesser known extramitochondrial isoform of frataxin detected in erythrocytes, frataxin-E, is encoded via an alternate transcript (FXN-E) originating in intron 1 that lacks a mitochondrial targeting sequence. We show that FXN-E is deficient in FRDA, including in patient-derived cell lines, iPS-derived proprioceptive neurons, and tissues from a humanized mouse model. In a series of FRDA patients, deficiency of frataxin-E protein correlated with the length of the expanded GAA triplet-repeat, and with repeat-induced DNA hypermethylation that occurs in close proximity to the intronic origin of FXN-E. CRISPR-induced epimodification to mimic DNA hypermethylation seen in FRDA reproduced FXN-E transcriptional deficiency. Deficiency of frataxin E is a consequence of FRDA-specific epigenetic silencing, and therapeutic strategies may need to address this deficiency.
        Performance of Conventional Urine Culture Compared to 16S rRNA Gene Amplicon Sequencing in Children with Suspected Urinary Tract Infection
        Christopher W. Marshall - 2021
        Abstract
        Because some organisms causing urinary tract infection (UTI) may be difficult to culture, examination of bacterial gene sequences in the urine may provide a more accurate view of bacteria present during a UTI. Our objective was to estimate how often access to 16S rRNA gene amplicon sequencing alters diagnosis and/or clinical management. The study was designed as a cross-sectional study of a convenience sample of children with suspected UTI. The setting was the emergency department or outpatient clinic at six pediatric centers. Participants included children 2 months to 10 years of age suspected of UTI. We categorized the results of urine culture as follows: “likely UTI” ($100,000 CFU/ml of a single uropathogen), “possible UTI” (10,000 to 99,000 CFU/ml of a uropathogen or $100,000 CFU/ ml of a single uropathogen plus other growth), and “unlikely UTI” (no growth or growth of nonuropathogens). Similarly, we categorized the results of 16S rRNA gene sequencing into the same three categories using the following criteria: likely UTI ($90% relative abundance of a uropathogen), possible UTI (50 to 89% relative abundance of a uropathogen), and unlikely UTI (remainder of samples). The main study outcome was concordance between conventional culture results and 16S rRNA gene sequencing. Concordance between the two methods was high in children with likely and unlikely UTI by conventional culture (95% and 87%, respectively). In children with possible UTI according to conventional culture, 71% had a single uropathogen at a relative abundance of $90% according to 16S rRNA gene sequencing data. Concordance between conventional culture and 16S rRNA gene amplicon sequencing appears to be high. In children with equivocal culture results, 16S rRNA gene results may provide information that may help clarify the diagnosis. IMPORTANCE Concordance between conventional culture and 16S rRNA gene amplicon sequencing appears to be high. In children with equivocal culture results, 16S rRNA gene results may provide information that may help clarify the diagnosis.
        The effect of a mass distribution of insecticide-treated nets on insecticide resistance and entomological inoculation rates of Anopheles gambiae s.l. in Bandundu City, Democratic Repub`lic of Congo
        Emery Metelo-Matubi - 2021
        Abstract
        Introduction insecticide-treated nets (ITNs) remain the mainstay of malaria vector control in the Democratic Republic of Congo. However, insecticide resistance of malaria vectors threatens their effectiveness. Entomological inoculation rates and insecticide susceptibility in Anopheles gambiae s.l. were evaluated before and after mass distribution of ITNs in Bandundu City for possible occurrence of resistance. Methods a cross-sectional study was conducted from 15th July 2015 to 15th June 2016. Adult mosquitoes were collected using pyrethrum spray catches and human landing catches and identified to species level and tested for the presence of sporozoites. Bioassays were carried out before and after distribution of ITNs to assess the susceptibility of adult mosquitoes to insecticides. Synergist bioassays were also conducted and target site mutations assessed using Polymerase chain reaction (PCR). Results a total of 1754 female An. gambiae s.l. were collected before and after deployment of ITNs. Fewer mosquitoes were collected after the distribution of ITNs. However, there was no significant difference in sporozoite rates or the overall entomological inoculation rate before and after the distribution of ITNs. Test-mosquitoes were resistant to deltamethrin, permethrin, and Dichlorodiphenyltrichloroethane but susceptible to bendiocarb. Pre-exposure of mosquitoes to Piperonyl butoxide increased their mortality after exposure to permethrin and deltamethrin. The frequency of the Kinase insert domain receptor (kdr)-West gene increased from 92 to 99% before and after the distribution of nets, respectively. Conclusion seasonal impacts could be a limiting factor in the analysis of these data; however, the lack of decrease in transmission after the distribution of new nets could be explained by the high-level of resistance to pyrethroid.
        Exploring the diversity of the deep sea—four new species of the amphipod genus Oedicerina described using morphological and molecular methods
        Anna M. Jazszewska - 2021
        Abstract
        Collections of the amphipod genus Oedicerina were obtained during six expeditions devoted to the study of deep-sea environments of the Pacific Ocean. The material revealed four species new to science. Two species (Oedicerina henrici sp. nov. and sp. nov.) were found at abyssal depths of the central eastern Pacific in the Clarion-Clipperton Zone; one species (sp. nov.) (Oedicerina claudei sp. nov.) was recovered in the Sea of Okhotsk (north-west Pacific), and one (Oedicerina lesci sp. nov.) in the abyss adjacent to the Kuril-Kamchatka Trench (KKT). The four new species differ from each other and known species by the shapes of the rostrum, coxae 1 and 4, basis of pereopod 7, armatures of pereonite 7, pleonites and urosomites. An identification key for all known species is provided. The study of the cytochrome c oxidase subunit I gene of the four new species and Oedicerina ingolfi collected in the North Atlantic confirmed their genetic distinction. However, small intraspecific variation within each of the studied species was observed. In the case of the new species occurring across the KKT, the same haplotype was found on both sides of the trench, providing evidence that the trench does not constitute an insurmountable barrier for population connectivity. None of the species have so far been found on both sides of the Pacific.
  • Next Generation Sequencing (NGS)
    • DNA
      Evaluation of nutrient characteristics and bacterial community in agricultural soil groups for sustainable land management
      Sumeth Wongkiew - 2022
      Abstract
      The soil bacterial community is critical for understanding biological processes in soils and is used for agricultural soil management. The understanding of microorganisms and ecology in different soil groups classified based on soil properties (e.g., minerals, soil texture, location, nitrogen, phosphorus, organic carbon and pH, among others), is limited. To suggest soil management strategies using bacterial data, we classified soils into four groups based on physical–chemical characteristics and elucidated their relationships with soil nutrient characteristics and the bacterial community in agricultural fields in Saraburi Province, Thailand. Results show that soil groups with high bacterial diversity had positive correlations with total Kjeldahl nitrogen and available phosphorus but were negatively affected by total organic carbon and pH levels. Dominant bacterial genera included Lactobacillus, Phascolarctobacterium, Prevotella, Clostridium, Gaiellales and Blautia. Significant key biomarkers were found (p < 0.05). Nutrient-rich soil groups (high available P, acidic pH) were found with genus Agromyces, while low nutrient soil groups (low available P, basic pH) were found with Hydrogenispora, Ignavibacterium and Bauldia. Based on co-occurrence networks, organic degrading bacteria functioned with other bacteria at high degrees of interconnections, suggesting organic amendment, biostimulation and biodegradation using nutrient-rich organic substrates could be used for agricultural soil improvements.
      Altered costimulatory signals and hypoxia support chromatin landscapes limiting the functional potential of exhausted T cells in cancer
      View ORCID ProfileB. Rhodes Ford - 2021
      Abstract
      Immunotherapy has changed cancer treatment with major clinical successes, but response rates remain low due in part to elevated prevalence of dysfunctional, terminally exhausted T cells. However, the mechanisms promoting progression to terminal exhaustion remain undefined. We profiled the histone modification landscape of tumor-infiltrating CD8 T cells throughout differentiation, finding terminally exhausted T cells possessed chromatin features limiting their transcriptional potential. Active enhancers enriched for bZIP/AP-1 transcription factor motifs lacked correlated gene expression, which were restored by immunotherapeutic costimulatory signaling. Epigenetic repression was also driven by an increase in histone bivalency, which we linked directly to hypoxia exposure. Our study is the first to profile the precise epigenetic changes during intratumoral differentiation to exhaustion, highlighting their altered function is driven by both improper costimulatory signals and environmental factors. These data suggest even terminally exhausted T cells remain poised for transcription in settings of increased costimulatory signaling and reduced hypoxia.
      Six de novo assemblies from pathogenic and non-pathogenic strains of Fusarium oxysporum f. sp. niveum
      James C. Fulton - 2021
      Abstract
      Fusarium wilt, caused by Fusarium oxysporum f. sp. niveum (Fon), is a soilborne disease which significantly limits yield in watermelon (Citrullus lanatus) and occasionally causes the loss of an entire year’s harvest. Reference-quality de novo genomic assemblies of pathogenic and non-pathogenic strains were generated using a combination of next-generation and third-generation sequencing technologies. Chromosomal-level genomes were produced with representatives from all Fon races facilitating comparative genomic analysis and the identification of chromosomal structural variation . Syntenic analysis between isolates allowed differentiation of the core and lineage-specific portions of their genomes. This research will support future efforts to refine the scientific understanding of the molecular and genetic factors underpinning the Fon host range, develop diagnostic assays for each of the four races, and decipher the evolutionary history of race 3.
  • Reverse Transcription
    • First-Strand cDNA Synthesis
      In Vivo Genome-Wide PGR Binding in Pregnant Human Myometrium Identifies Potential Regulators of Labor
      Arial J. Dotts - 2022
      Abstract
      The alterations in myometrial biology during labor are not well understood. The myometrium is the contractile portion of the uterus and contributes to labor, a process that may be regulated by the steroid hormone progesterone. Thus, human myometrial tissues from term pregnant in-active-labor (TIL) and term pregnant not-in-labor (TNIL) subjects were used for genome-wide analyses to elucidate potential future preventive or therapeutic targets involved in the regulation of labor. Using myometrial tissues directly subjected to RNA sequencing (RNA-seq), progesterone receptor (PGR) chromatin immunoprecipitation sequencing (ChIP-seq), and histone modification ChIP-seq, we profiled genome-wide changes associated with gene expression in myometrial smooth muscle tissue in vivo. In TIL myometrium, PGR predominantly occupied promoter regions, including the classical progesterone response element, whereas it bound mainly to intergenic regions in TNIL myometrial tissue. Differential binding analysis uncovered over 1700 differential PGR-bound sites between TIL and TNIL, with 1361 sites gained and 428 lost in labor. Functional analysis identified multiple pathways involved in cAMP-mediated signaling enriched in labor. A three-way integration of the data for ChIP-seq, RNA-seq, and active histone marks uncovered the following genes associated with PGR binding, transcriptional activation, and altered mRNA levels: ATP11A, CBX7, and TNS1. In vitro studies showed that ATP11A, CBX7, and TNS1 are progesterone responsive. We speculate that these genes may contribute to the contractile phenotype of the myometrium during various stages of labor. In conclusion, we provide novel labor-associated genome-wide events and PGR-target genes that can serve as targets for future mechanistic studies.
      Transactivation of TrkB Receptors by Oxytocin and Its G Protein-Coupled Receptor
      Mariela Mitre - 2022
      Abstract
      Brain-derived Neurotrophic Factor (BDNF) binds to the TrkB tyrosine kinase receptor, which dictates the sensitivity of neurons to BDNF. A unique feature of TrkB is the ability to be activated by small molecules in a process called transactivation. Here we report that the brain neuropeptide oxytocin increases BDNF TrkB activity in primary cortical neurons and in the mammalian neocortex during postnatal development. Oxytocin produces its effects through a G protein-coupled receptor (GPCR), however, the receptor signaling events that account for its actions have not been fully defined. We find oxytocin rapidly transactivates TrkB receptors in bath application of acute brain slices of 2-week-old mice and in primary cortical culture by increasing TrkB receptor tyrosine phosphorylation. The effects of oxytocin signaling could be distinguished from the related vasopressin receptor. The transactivation of TrkB receptors by oxytocin enhances the clustering of gephyrin, a scaffold protein responsible to coordinate inhibitory responses. Because oxytocin displays pro-social functions in maternal care, cognition, and social attachment, it is currently a focus of therapeutic strategies in autism spectrum disorders. Interestingly, oxytocin and BDNF are both implicated in the pathophysiology of depression, schizophrenia, anxiety, and cognition. These results imply that oxytocin may rely upon crosstalk with BDNF signaling to facilitate its actions through receptor transactivation.
      Cerebrospinal fluid of progressive multiple sclerosis patients reduces differentiation and immune functions of oligodendrocyte progenitor cells
      Omri Zveik - 2022
      Abstract
      Oligodendrocyte progenitor cells (OPCs) are responsible for remyelination in the central nervous system (CNS) in health and disease. For patients with multiple sclerosis (MS), remyelination is not always successful, and the mechanisms differentiating successful from failed remyelination are not well-known. Growing evidence suggests an immune role for OPCs, in addition to their regenerative role; however, it is not clear if this helps or hinders the regenerative process. We studied the effect of cerebrospinal fluid (CSF) from relapsing MS (rMS) and progressive MS (pMS) patients on primary OPC differentiation and immune gene expression and function. We observed that CSF from either rMS or pMS patients has a differential effect on the ability of mice OPCs to differentiate into mature oligodendrocytes and to express immune functions. CSF of pMS patients impaired differentiation into mature oligodendrocytes. In addition, it led to decreased major histocompatibility complex class (MHC)-II expression, tumor necrosis factor (TNF)-α secretion, nuclear factor kappa-B (NFκB) activation, and less activation and proliferation of T cells. Our findings suggest that OPCs are not only responsible for remyelination, but they may also play an active role as innate immune cells in the CNS.
      The Betacoronavirus PHEV Replicates and Disrupts the Respiratory Epithelia and Upregulates Key Pattern Recognition Receptor Genes and Downstream Mediators, Including IL-8 and IFN-l
      Rahul Nelli - 2021
      Abstract
      The upper respiratory tract is the primary site of infection by porcine hemagglutinating encephalomyelitis virus (PHEV). In this study, primary porcine respiratory epithelial cells (PRECs) were cultured in an air-liquid interface (ALI) to differentiate into a pseudostratified columnar epithelium, proliferative basal cells, M cells, ciliated cells, and mucus-secreting goblet cells. ALI-PRECs recreates a cell culture environment morphologically and functionally more representative of the epithelial lining of the swine trachea than traditional culture systems. PHEV replicated actively in this environment, inducing cytopathic changes and progressive disruption of the mucociliary apparatus. The innate immunity against PHEV was comparatively evaluated in ALI-PREC cultures and tracheal tissue sections derived from the same cesarean-derived, colostrum-deprived (CDCD) neonatal donor pigs. Increased expression levels of TLR3 and/or TLR7, RIG1, and MyD88 genes were detected in response to infection, resulting in the transcriptional upregulation of IFN-l1 in both ALI-PREC cultures and tracheal epithelia. IFN-l1 triggered the upregulation of the transcription factor STAT1, which in turn induced the expression of the antiviral IFN-stimulated genes OAS1 and Mx1. No significant modulation of the major proinflammatory cytokines interleukin-1b (IL-1b), IL-6, and tumor necrosis factor alpha (TNF-a) was detected in response to PHEV infection. However, a significant upregulation of different chemokines was observed in ALI-PREC cultures (CCL2, CCL5, CXCL8, and CXCL10) and tracheal epithelium (CXCL8 and CXCL10). This study shed light on the molecular mechanisms driving the innate immune response to PHEV at the airway epithelium, underscoring the important role of respiratory epithelial cells in the maintenance of respiratory homeostasis and on the initiation, resolution, and outcome of the infectious process. IMPORTANCE The neurotropic betacoronavirus porcine hemagglutinating encephalomyelitis virus (PHEV) primarily infects and replicates in the swine upper respiratory tract, causing vomiting and wasting disease and/or encephalomyelitis in suckling pigs. This study investigated the modulation of key early innate immune genes at the respiratory epithelia in vivo, on tracheal tissue sections from experimentally infected pigs, and in vitro, on air-liquid interface porcine respiratory cell cultures. The results from the study underscore the important role of respiratory epithelial cells in maintaining respiratory homeostasis and on the initiation, resolution, and outcome of the PHEV infectious process
  • Sample Preparation
    • DNA
      Plaque-associated human microglia accumulate lipid droplets in a chimeric model of Alzheimer’s disease
      Christel Claes - 2021
      Abstract
      Background Disease-associated microglia (DAMs), that surround beta-amyloid plaques, represent a transcriptionally-distinct microglial profile in Alzheimer’s disease (AD). Activation of DAMs is dependent on triggering receptor expressed on myeloid cells 2 (TREM2) in mouse models and the AD TREM2-R47H risk variant reduces microglial activation and plaque association in human carriers. Interestingly, TREM2 has also been identified as a microglial lipid-sensor, and recent data indicates lipid droplet accumulation in aged microglia, that is in turn associated with a dysfunctional proinflammatory phenotype. However, whether lipid droplets (LDs) are present in human microglia in AD and how the R47H mutation affects this remains unknown. Methods To determine the impact of the TREM2 R47H mutation on human microglial function in vivo, we transplanted wild-type and isogenic TREM2-R47H iPSC-derived microglial progenitors into our recently developed chimeric Alzheimer mouse model. At 7 months of age scRNA-seq and histological analyses were performed. Results Here we report that the transcriptome of human wild-type TREM2 and isogenic TREM2-R47H DAM xenografted microglia (xMGs), isolated from chimeric AD mice, closely resembles that of human atherosclerotic foam cells. In addition, much like foam cells, plaque-bound xMGs are highly enriched in lipid droplets. Somewhat surprisingly and in contrast to a recent in vitro study, TREM2-R47H mutant xMGs exhibit an overall reduction in the accumulation of lipid droplets in vivo. Notably, TREM2-R47H xMGs also show overall reduced reactivity to plaques, including diminished plaque-proximity, reduced CD9 expression, and lower secretion of plaque-associated APOE. Conclusions Altogether, these results indicate lipid droplet accumulation occurs in human DAM xMGs in AD, but is reduced in TREM2-R47H DAM xMGs, as it occurs secondary to TREM2-mediated changes in plaque proximity and reactivity.
  • Real-Time qPCR
    Echovirus 9 genetic diversity detected in whole-capsid genome sequences obtained directly from clinical specimens using next generation sequencing
    Erika Bujaki - 2022
    Abstract
    Echovirus 9 (E9) has been detected in an increased number of symptomatic patient samples received by the National Enterovirus Reference Laboratory in Hungary during 2018 compared to previously reported years. Formerly identified E9 viruses from different specimen types detected from patients of various ages and showing differing clinical signs were chosen for the detailed analysis of genetic relationships and potential variations within the viral populations. We used next generation sequencing (NGS) analysis of 3,900 nucleotide long amplicons covering the entire capsid coding region of the viral genome without isolation, directly from clinical samples. Compared to the E9 reference strain, the viruses showed about 79% nucleotide and around 93% amino acid sequence similarity. The four new viral genome sequences had 1-20 nucleotide differences between them also resulting in 6 amino acid variances in the coding region, including 3 in the structural VP1 capsid protein. One virus from a patient with hand, foot, and mouth disease had two amino acid changes in the VP1 capsid protein. An amino acid difference was also detected in the non-structural 2C gene of one virus sequenced from a throat swab sample from a patient with meningitis, compared to the faecal specimen taken two days later. Two amino acid changes, one in the capsid protein, were found between faecal samples of meningitis patients of different ages. Sequencing the whole capsid genome revealed several nucleotide and amino acid differences between E9 virus strains detected in Hungary in 2018.
    Novel Roles of the Nipah Virus Attachment Glycoprotein and Its Mobility in Early and Late Membrane Fusion Steps
    Victoria Ortega - 2022
    Abstract
    The Paramyxoviridae family comprises important pathogens that include measles (MeV), mumps, parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). Paramyxoviral entry into cells requires viral-cell membrane fusion, and formation of paramyxoviral pathognomonic syncytia requires cell-cell membrane fusion. Both events are coordinated by intricate interactions between the tetrameric attachment (G/H/HN) and trimeric fusion (F) glycoproteins. We report that receptor binding induces conformational changes in NiV G that expose its stalk domain, which triggers F through a cascade from prefusion to prehairpin intermediate (PHI) to postfusion conformations, executing membrane fusion. To decipher how the NiV G stalk may trigger F, we introduced cysteines along the G stalk to increase tetrameric strength and restrict stalk mobility. While most point mutants displayed near-wild-type levels of cell surface expression and receptor binding, most yielded increased NiV G oligomeric strength, and showed remarkably strong defects in syncytium formation. Furthermore, most of these mutants displayed stronger F/G interactions and significant defects in their ability to trigger F, indicating that NiV G stalk mobility is key to proper F triggering via moderate G/F interactions. Also remarkably, a mutant capable of triggering F and of fusion pore formation yielded little syncytium formation, implicating G or G/F interactions in a late step occurring post fusion pore formation, such as the extensive fusion pore expansion required for syncytium formation. This study uncovers novel mechanisms by which the G stalk and its oligomerization/mobility affect G/F interactions, the triggering of F, and a late fusion pore expansion step—exciting novel findings for paramyxoviral attachment glycoproteins. IMPORTANCE The important Paramyxoviridae family includes measles, mumps, human parainfluenza, and the emerging deadly zoonotic Nipah virus (NiV) and Hendra virus (HeV). The deadly emerging NiV can cause neurologic and respiratory symptoms in humans with a .60% mortality rate. NiV has two surface proteins, the receptor binding protein (G) and fusion (F) glycoproteins. They mediate the required membrane fusion during viral entry into host cells and during syncytium formation, a hallmark of paramyxoviral and NiV infections. We previously discovered that the G stalk domain is important for triggering F (via largely unknown mechanisms) to induce membrane fusion. Here, we uncovered new roles and mechanisms by which the G stalk and its mobility modulate the triggering of F and also unexpectedly affect a very late step in membrane fusion, namely fusion pore expansion. Importantly, these novel findings may extend to other paramyxoviruses, offering new potential targets for therapeutic interventions.
    Point-of-Care Platform for Rapid Multiplexed Detection of SARS-CoV-2 Variants and Respiratory Pathogens
    Alexander Y. Trick - 2022
    Abstract
    The rise of highly transmissible SARS-CoV-2 variants brings new challenges and concerns with vaccine efficacy, diagnostic sensitivity, and public health responses to end the pandemic. Widespread detection of variants is critical to inform policy decisions to mitigate further spread, and postpandemic multiplexed screening of respiratory viruses will be necessary to properly manage patients presenting with similar respiratory symptoms. In this work, a portable, magnetofluidic cartridge platform for automated polymerase chain reaction testing in <30 min is developed. Cartridges are designed for multiplexed detection of SARS-CoV-2 with either identification of variant mutations or screening for Influenza A and B. Moreover, the platform can perform identification of B.1.1.7 and B.1.351 variants and the multiplexed SARS-CoV-2/Influenza assay using archived clinical nasopharyngeal swab eluates and saliva samples. This work illustrates a path toward affordable and immediate testing with potential to aid surveillance of viral variants and inform patient treatment.
    Specific inhibition of the NLRP3 inflammasome suppresses immune overactivation and alleviates COVID-19 like pathology in mice
    Jianxiong Zeng - 2022
    Abstract
    Background The Coronavirus Disease 2019 (COVID-19) pandemic has been a great threat to global public health since 2020. Although the advance on vaccine development has been largely achieved, a strategy to alleviate immune overactivation in severe COVID-19 patients is still needed. The NLRP3 inflammasome is activated upon SARS-CoV-2 infection and associated with COVID-19 severity. However, the processes by which the NLRP3 inflammasome is involved in COVID-19 disease remain unclear. Methods We infected THP-1 derived macrophages, NLRP3 knockout mice, and human ACE2 transgenic mice with live SARS-CoV-2 in Biosafety Level 3 (BSL-3) laboratory. We performed quantitative real-time PCR for targeted viral or host genes from SARS-CoV-2 infected mouse tissues, conducted histological or immunofluorescence analysis in SARS-CoV-2 infected mouse tissues. We also injected intranasally AAV-hACE2 or intraperitoneally NLRP3 inflammasome inhibitor MCC950 before SARS-CoV-2 infection in mice as indicated. Findings We have provided multiple lines of evidence that the NLRP3 inflammasome plays an important role in the host immune response to SARS-CoV-2 invasion of the lungs. Inhibition of the NLRP3 inflammasome attenuated the release of COVID-19 related pro-inflammatory cytokines in cell cultures and mice. The severe pathology induced by SARS-CoV-2 in lung tissues was reduced in Nlrp3−/− mice compared to wild-type C57BL/6 mice. Finally, specific inhibition of the NLRP3 inflammasome by MCC950 alleviated excessive lung inflammation and thus COVID-19 like pathology in human ACE2 transgenic mice. Interpretation Inflammatory activation induced by SARS-CoV-2 is an important stimulator of COVID-19 related immunopathology. Targeting the NLRP3 inflammasome is a promising immune intervention against severe COVID-19 disease.
    Autologous Transplantation of Skin-Derived Precursor Cells in a Porcine Model
    Anne-Laure Thomas - 2020
    Abstract
    Background Hirschprung's disease is characterized by aganglionic bowel and often requires surgical resection. Cell-based therapies have been investigated as potential alternatives to restore functioning neurons. Skin-derived precursor cells (SKPs) differentiate into neural and glial cells in vitro and generate ganglion-like structures in rodents. In this report, we aimed to translate this approach into a large animal model of aganglionosis using autologous transplantation of SKPs. Methods Juvenile pigs underwent skin procurement from the shoulder and simultaneous chemical denervation of an isolated colonic segment. Skin cells were cultured in neuroglial-selective medium and labeled with fluorescent dye for later identification. The cultured SKPs were then injected into the aganglionic segments of colon, and the specimens were retrieved within seven days after transplantation. SKPs in vitro and in vivo were assessed with histologic samples for various immunofluorescent markers of multipotency and differentiation. SKPs from the time of harvest were compared to those at the time of injection using PCR. Results Prior to transplantation, 72% of SKPs stained positive for nestin and S100b, markers of neural and glial precursor cells of neural crest origin, respectively. Markers of differentiated neurons and gliocytes, TUJ1 and GFAP, were detected in 47% of cultured SKPs. After transplantation, SKPs were identified in both myenteric and submucosal plexuses of the treated colon. Nestin co-expression was detected in the SKPs within the aganglionic colon in vivo. Injected SKPs appeared to migrate and express early neuroglial differentiation markers. Conclusions Autologous SKPs implanted into aganglionic bowel demonstrated immunophenotypes of neuroglial progenitors. Our results suggest that autologous SKPs may be potentially useful for cell-based therapy for patients with enteric nervous system disorders. Type of Study Basic science.

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