Biology subjects

Meurens, F.

Publications and source records attributed to Meurens, F..

6 recordsLinked to original sources

bioRxiv2026

Determination of suitable reference genes for RT-qPCR analysis in Gryllodes sigillatus (Orthoptera: Gryllidae)

The tropical house cricket Gryllodes sigillatus is a major species used in the edible insect farming industry. Despite the rapid expansion of this sector, diagnostic tools for detecting infections in these species remain limited. The lack of validated reference genes compromises the reliability of RT-qPCR-based gene expression analyses, which are essential for the development of molecular tools for disease diagnosis and health monitoring in insect production systems. To address this gap, we evaluated the expression stability of six candidate reference genes (ACTB, EF1, GAPDH, HisH3, RPL5, and 18SrRNA) across four body parts (abdomen, head, legs, and whole body) using a combination of complementary statistical approaches, including geNorm, NormFinder, BestKeeper, the {Delta}Ct method, the R statistical environment, and the integrated RefFinder tool. Candidate genes were identified and annotated using the recently published G. sigillatus genome, through sequence comparisons with closely related insect species using BLAST and reciprocal BLAST analyses, multiple sequence alignments. All procedures complied with MIQE 2.0 guidelines to ensure methodological rigor and transparency. The results showed that ACTB, EF1, RPL5, and 18SrRNA exhibited stable and consistent expression across all analyzed tissues, whereas GAPDH and HisH3 displayed high variability and were generally unsuitable for normalization, except in head tissue where GAPDH remained stable. This study provides the first validated set of reference genes for G. sigillatus, establishing a robust foundation for accurate, reproducible, and comparable gene expression analyses. Furthermore, these findings support the development of RT-qPCR-based diagnostic tools, contributing to improved health monitoring and biosafety in insect production systems.

molecular biology↗

bioRxiv2025

Reference Gene Selection for Accurate RT-qPCR Normalization in Four Tissues and Whole-Body Samples of Acheta domesticus

House crickets (Acheta domesticus) are increasingly recognized as a sustainable protein source for food and feed systems. However, despite their growing relevance, molecular research on this species remains extremely limited, particularly concerning robust normalization strategies for gene expression analysis. This study is the first to identify and validate suitable reference genes for RT-qPCR analysis in A. domesticus across different tissues, an essential step for accurate quantification of host and pathogen target gene expression. Six candidate reference genes commonly used in insects (AdoNEOPT, EF2, 18S rRNA, EF1, Histone H3, and GAPDH) were evaluated for expression stability in five tissue types (abdomen, legs, wings, head, and whole body). Gene stability was assessed using five computational tools: BestKeeper, geNorm, NormFinder, Delta Ct, and the integrated platform RefFinder. Additional validation was performed using the R statistical software. The results identified EF1, AdoNEOPT, EF2, and 18S rRNA as the most stable reference genes across all the selected tissues, while GAPDH and His H3 showed high variability and were generally unsuitable except in the head, where GAPDH demonstrated stable expression. This study provides the first validated set of reference genes for A. domesticus, laying a foundation for accurate and reproducible gene expression studies. Moreover, our study will enable the development of new diagnostic tests based on qPCR and molecular signatures. These tests will be essential tools for health monitoring in insect farms, which remain exposed to emerging diseases.

molecular biology↗

bioRxiv2024

Comparative impact of porcine reproductive and respiratory virus and swine influenza A virus infections on respiratory lymph nodes B cells and macrophages.

Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) strongly impacts the pig rearing sector due to its persistence in infected animals. Interestingly, although the PRRSV family exhibits considerable genome variability, with the PRRSV-1 and PRRSV-2 subtypes having been finally classified in two different species (Betaarterivirus suid 1 and 2). Both viruses, as well as their derived-attenuated vaccine strains, persist for months, due in part to their ability to delay the appearance of neutralizing antibodies. Thanks to extensive efforts over the past years, we have developed the capability to perform in-depth analysis of the previously poorly understood porcine inverted lymph node (LN). In this study, by comparing the early stages of LN B cell maturation upon PRRSV-1 infection to those induced upon the acute swine influenza A virus infection, we highlighted PRRSV-specific mechanisms, including the expression of PD-L1 in efferent macrophages, the induction of extrafollicular plasmocytes, and the influx of inflammatory monocytes/macrophages. Studies on PRRSV-2 infections report observations compatible with our results, that thus might be generalized to all PRRSV-strains. Moreover, these mechanisms can be compared with those used by the human immunodeficiency virus (HIV) and the murine chronic lymphocytic choriomeningitis virus (LCMV) to hijack the immune response. These similarities can be harnessed to develop new strategies to improve the development of more efficient anti-PRRSV vaccines.

immunology↗

bioRxiv2022

The porcine cGAS-STING pathway exerts an unusual antiviral function independent of IFN and autophagy

The innate immune DNA sensing cGAS-STING pathway exerts strong antiviral activity through the downstream interferon (IFN) production; however, it has been recently recognized that IFN independent activity of STING also plays an important role in antiviral functions. Nevertheless, the IFN independent antiviral activity of STING is not fully understood. In this study, we showed that porcine STING (pSTING) played a critical role in anti-HSV1 and anti-VSV infections, and IFN defective mutants including pSTING pLxIS sub, S365A and {Delta}CTT all exhibited similar antiviral functions to wild type (WT) pSTING. Further, all these IFN defective pSTING mutants possessed a comparable autophagy activity relative to WT pSTING as expected. From pSTING WT, S365A and {Delta}CTT, the residues responsible for autophagy were mutated, which included L333A/R334A, Y167A/L170A and Y245A/L248A, respectively. Surprisingly, all these autophagy defective pSTING mutants still resisted from the two viral infections, demonstrating the pSTING antiviral function independent of IFN as well as autophagy. On the other hand, all the autophagy defective pSTING mutants triggered cell apoptosis, which was associated with the antiviral functions. Additionally, pSTING lost its antiviral activity in TBK1-/- and IRF3-/- porcine macrophages, indicating the involvement of TBK1 and IRF3 in other STING activity such as apoptosis. Collectively, our results revealed that STING exerts both IFN and autophagy independent antiviral activity, and also suggested that STING triggered cell apoptosis might resist from virus infections.

immunology↗

bioRxiv2021

African swine fever virus structural protein p17 inhibits cGAS-STING signaling pathway through interacting with STING

African swine fever (ASF) is highly contagious, causes high mortality in domestic and feral swine, and has a significant economic impact on the global swine industry due to the lack of a vaccine or an effective treatment. African swine fever virus (ASFV) encodes more than 150 polypeptides, which may have intricate and delicate interactions with the host for the benefit of the virus to evade the hosts defenses. However, currently, there is still a lack of information regarding the roles of the viral proteins in host cells. Here, our data demonstrated that the p17, encoded by D117L gene could suppress porcine cGAS-STING signaling pathway, exhibiting the inhibitions of TBK1 and IRF3 phosphorylations, downstream promoter activities, cellular mRNA transcriptions and ISG56 induction, and antiviral responses. Further, we found that p17 was located in endoplasmic reticulum (ER) and Golgi apparatus, and interacted with STING, perturbing it in the recruitment of TBK1 and IKK{varepsilon}. Additionally, it appeared that the transmembrane domain (amino acids 39-59) of p17 could be required for interacting with STING and inhibiting cGAS-STING pathway. Taken together, p17 could inhibit the cGAS-STING pathway through its interaction with STING and interference with STING in the recruitment of TBK1 and IKK{varepsilon}. ImportanceAfrican swine fever (ASF) is a highly contagious disease in domestic and feral swine, posing significant economic impacts on the global swine industry, and the pathogen ASFV is a large icosahedral DNA virus. The innate immune cGAS-STING DNA sensing pathway plays a critical role in sensing invading ASFV and triggering antiviral responses. However, there is still a lack of information regarding the molecular mechanisms of ASFV evasion of the cGAS-STING pathway. We have analyzed the effects of whole genomic open reading frames (ORFs) of ASFV China 2018/1 on the activation of cGAS-STING pathway, and found that p17 was able to inhibit cGAS-STING mediated type I IFN production by targeting STING, altering its capacity to recruit both TBK1 and IKK{varepsilon}. Findings presented here will expand our knowledge on the molecular mechanisms by which ASFV counteracts the antiviral innate immunity and provide deep insights into ASF pathogenesis.

immunology↗

bioRxiv2021

The African swine fever virus protease pS273R inhibits DNA sensing cGAS-STING pathway by targeting IKKε

African swine fever virus (ASFV), a large and complex cytoplasmic double-stranded DNA virus, has developed multiple strategies to evade the antiviral innate immune responses. Cytosolic DNA arising from invading ASFV is mainly detected by the cyclic GMP-AMP synthase (cGAS) and then triggers a series of innate immune responses to prevent virus invasion. However, the immune escape mechanism of ASFV remains to be fully clarified. The pS273R of ASFV is a member of the SUMO-1-specific protease family and is crucial for valid virus replication. In this study, we identified pS273R as a suppressor of cGAS-STING pathway mediated type I interferon (IFN) production by ASFV genomic open reading frame screening. The pS273R was further confirmed as an inhibitor of IFN production as well as its downstream antiviral genes in cGAS-STING pathway. Mechanistically, pS273R greatly decreased the cGAS-STING signaling by targeting IKK{varepsilon} but not TBK1 and pS273R was found to disturb the interaction between IKK{varepsilon} and STING through its interaction with IKK{varepsilon}. Further, mutational analyses revealed that pS273R antagonized the cGAS-STING pathway by enzyme catalytic activity, which may affect the IKK{varepsilon} sumoylation state required for the interaction with STING. In summary, our results revealed for the first time that pS273R acts as an obvious negative regulator of cGAS-STING pathway by targeting IKK{varepsilon} via its enzymatic activity, which shows a new immune evasion mechanism of ASFV. ImportanceAfrican swine fever (ASF) is a devastating disease for domestic pigs and wild boar and the pathogen ASFV is a cytoplasmic double-stranded DNA virus. The innate immune cGAS-STING-IFN signaling pathway exerts a critical role in sensing ASFV infection. However, the functions of half ASFV encoded 150 plus proteins are still unknown and the evasion against the cGAS-STING pathway is not resolved. In our study, via ASFV genomic open reading frame (ORF) screening, we found that 29 ASFV proteins could inhibit cGAS-STING signaling pathway, with pS273R showing the most obvious inhibitory effect. Surprisingly, pS273R was found to antagonize the cGAS-STING signaling by targeting IKK{varepsilon}. Moreover, the pS273R enzyme activity is required for its ability to inhibit the cGAS-STING pathway. Our findings deepen the understanding of the immune evasion mechanism of ASFV, which will provide a support for the development of safe and effective ASFV vaccines.

immunology↗