Biology subjects

Sid, H.

Publications and source records attributed to Sid, H..

5 recordsLinked to original sources

bioRxiv2026

Opposing roles of ACE2 and TMPRSS2 in IBV Beaudette infection

Infectious bronchitis virus (IBV) is an economically important avian gammacoronavirus. IBV uses sialic acids and heparan sulfate for cellular attachment, but the host proteins governing its infection remain poorly defined. Here, we investigated the roles of angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) during IBV Beaudette (IBV BD) infection. ACE2 knockout impaired IBV replication in DF-1 cells, whereas ACE2 reconstitution restored infection. Furthermore, ACE2 overexpression enhanced infection of DF-1 and primary chicken embryo kidney cells, supporting the role of chicken ACE2 as a proviral host factor. In contrast, TMPRSS2 exerted a restrictive function on IBV BD infection as demonstrated in TMPRSS2 KO DF-1 cells and upon pharmacological inhibition, which significantly increased IBV BD infection in DF-1 and Vero cells. RNA sequencing revealed significant changes in lipid metabolism and membrane-related processes following TMPRSS2 knockout and pharmacological inhibition. These findings highlight the opposing roles of ACE2 and TMPRSS2 in IBV BD infection, emphasizing the combined impact of proviral host factors, protease activity, and the cellular membrane environment during gammacoronavirus infections.

microbiology↗

bioRxiv2025

Type I and type III interferon receptor knockout chickens: Novel models for unraveling interferon dynamics in influenza infection

The rapid cross-species transmission of highly pathogenic avian influenza presents a significant zoonotic threat. Elucidating the avian interferon (IFN) system, the primary antiviral defense in chickens, is critical for controlling the virus at its source and preventing its spillover into humans and other species. We engineered type I (IFN-/{beta}) and type III (IFN-{lambda}) IFN receptor knockout chickens to dissect the role of IFNs in viral infections. Results revealed that type I IFN predominantly modulates innate immune cell populations, T cell subsets, and their contribution to antibody production following immunization under physiological conditions. In ovo and in vivo challenge experiments utilizing diverse influenza A virus strains demonstrated strain-specific roles of both IFN-/{beta} and IFN-{lambda} in orchestrating viral pathogenesis, immunological responses, and tissue-tropism effects. Notably, type I IFN was particularly crucial in the initial defense mechanisms against H3N1 avian influenza A virus infection. These novel models offer unprecedented insights into avian IFN biology within the context of avian influenza, which is essential for developing more effective strategies to prevent and control this public health challenge.

immunology↗

bioRxiv2023

Reinstatement of RIG-I in chickens via genetic modification reveals new insights into the dynamic evolution of avian immune sensors

Retinoic acid-inducible gene I (RIG-I) activates mitochondrial antiviral signaling proteins, initiating the antiviral response. RIG-I and RNF135, a ubiquitin ligase regulator, are missing in domestic chickens but conserved in mallard ducks. The chickens RIG-I loss was long believed to be linked to increased avian influenza susceptibility. We reinstated both genes in chickens and examined their susceptibility to infection with an H7N1 avian influenza virus. Uninfected RIG-I-expressing chickens exhibited shifts in T and B cells. At the same time, the H7N1 infection led to severe disease, persistent weight loss, and increased viral replication compared to wild-type chickens. The simultaneous expression of RIG-I and RNF135 potentiated the RIG-I activity and was associated with exacerbated inflammatory response and increased mortality without influencing virus replication. Additional animal infection experiments with two other avian influenza viruses validated these findings. They confirmed that the harmful effects triggered by RIG-I or RIG-I-RNF135-expression require a minimum degree of viral virulence. Our data indicate that the loss of RIG-I in chickens has likely evolved to counteract deleterious inflammation caused by viral infection and highlight an outcome of restoring evolutionary lost genes in birds. Significance StatementThe evolutionary loss of a crucial innate immune sensor like RIG-I in domestic chickens and its presence in closely related avian species such as ducks has long puzzled researchers. We genetically reinstated RIG-I in chickens, alongside its ubiquitination factor, RNF135, to uncover their roles in responding to influenza virus interactions in chickens. Our findings suggest that the loss of RIG-I in chickens may have occurred as an adaptive strategy to mitigate harmful inflammation associated with influenza infection. We shed light on an outcome of reinstating evolutionarily lost genes in birds and open new avenues for understanding immune responses in vertebrates.

immunology↗

bioRxiv2023

Knockout of αβ but not γδ T cells in chickens is associated with high cytotoxicity and deficiency of regulatory and helper T cells

The availability of genetically modified mice has facilitated the study of mammalian T cells. No model has yet been developed to study these cells in chicken, an important livestock species with a high availability of {gamma}{delta} T cells. To investigate the role of {gamma}{delta} and {beta} T cell populations in birds, we generated chickens lacking these T cell populations. This was achieved by genomic deletion of the constant region of the T cell receptor {gamma} or {beta} chain, leading to a complete loss of either {gamma}{delta} or {beta} T cells. Our results show that a deletion of {beta} T cells but not {gamma}{delta} T cells resulted in a severe phenotype in knockout chickens. The {beta} T cell knockout chickens exhibited granulomas associated with inflammation of the spleen and the proventriculus. Immunophenotyping of {beta} T cell knockout chickens revealed a significant increase in monocytes and the absence of CD4+ T cells and FoxP3+ regulatory T cells compared to wild type chickens. In addition, we observed a significant decrease in immunoglobulins, B lymphocytes, and changes in the bursa morphology. Our data reveal the consequences of T cell knockouts in chickens and provide new insights into their function in vertebrates. Significance statementThe lack of genetically modified chickens has severely limited research in avian immunology compared to other animal models. Here, we report the generation of two T cell knockout chicken lines that will contribute significantly to the understanding of T cell biology as a very important research model as well as an important livestock species. The generated animals reveal the function of different T cell populations in chickens and will help to better understand the role of these cells during the interaction with various pathogens in birds.

immunology↗

bioRxiv2020

Resources for genome editing in livestock: Cas9-expressing chickens and pigs

Genetically modified animals continue to provide important insights in biomedical sciences. Research has focused mostly on genetically modified mice so far, but other species like pigs resemble more closely the human physiology. In addition, cross-species comparisons with phylogenetically distant species such as chickens provide powerful insights into fundamental biological and biomedical processes. One of the most versatile genetic methods applicable across species is CRISPR/Cas9. Here, we report for the first time the generation of Cas9 transgenic chickens and pigs that allow in vivo genome editing in these two important agricultural species. We demonstrated that Cas9 is constitutively expressed in all organs of both species and that the animals are healthy and fertile. In addition, we confirmed the functionality of Cas9 for a number of different target genes and for a variety of cell types. Taken together, these transgenic animal species expressing Cas9 provide an unprecedented tool for agricultural and biomedical research, and will facilitate organ specific reverse genetics as well as cross-species comparisons. Significance statementGenome engineering of animals is crucial for translational medicine and the study of genetic traits. Here, we generated transgenic chickens and pigs that ubiquitously express the Cas9 endonuclease, providing the basis for in vivo genome editing. We demonstrated the functionality of this system by successful genome editing in chicken and porcine cells and tissues. These animals facilitate organ specific in vivo genome editing in both species without laborious germ line modifications, which will reduce the number of animals needed for genetic studies. They also provide a new tool for functional genomics, developmental biology and numerous other applications in biomedical and agricultural science.

molecular biology↗