Project description:Ulcerative colitis is a chronic inflammatory disorder for which a definitive cure is still missing. This is characterized by an overwhelming inflammatory milieu in the colonic tract where a composite set of immune and non-immune cells orchestrate its pathogenesis. Over the last years, a growing body of evidence has been pinpointing gut virome dysbiosis as underlying its progression. Nonetheless, its role during the early phases of chronic inflammation is far from being fully defined. Here we show the gut virome-associated Hepatitis B virus protein X, most likely acquired after an event of zoonotic spillover, to be associated with the early stages of ulcerative colitis and to induce colonic inflammation in mice. It acts as a transcriptional regulator in epithelial cells, provoking barrier leakage and altering mucosal immunity at the level of both innate and adaptive immunity. This study paves the way to the comprehension of the aetiopathogenesis of intestinal inflammation and encourages further investigations of the virome as a trigger also in other scenarios. Moreover, it provides a brand-new standpoint that looks at the virome as a target for tailored treatments, blocking the early phases of chronic inflammation and possibly leading to better disease management.
2023-02-20 | GSE204665 | GEO
Project description:Virus diversity, wildlife-domestic animal circulation and potential zoonotic viruses of small mammals, pangolins and zoo animals
Project description:The emergence of influenza A viruses (IAV) from zoonotic reservoirs poses a great threat to human health. As seasonal vaccines are ineffective against zoonotic strains, and newly transmitted viruses can quickly acquire drug resistance, there remains a need for host- directed therapeutics against IAV. Here, we performed a genome-scale CRISPR/Cas9 knockout screen in human lung epithelial cells with a human isolate of an avian H5N1 strain. Several genes involved in sialic acid biosynthesis and related glycosylation pathways were highly enriched post-H5N1 selection, including SLC35A1, a sialic acid transporter essential for IAV receptor expression and thus viral entry. Importantly, we have identified capicua (CIC) as a negative regulator of cell intrinsic immunity, as loss of CIC resulted in heightened antiviral responses and restricted replication of multiple viruses. Therefore, our study demonstrates that the CRISPR/Cas9 system can be utilized for the discovery of host factors critical for the replication of intracellular pathogens.
Project description:<p>Definition of the human microbiome is an important scientific priority. This study will expand the scope of the investigation to include viruses, which account for a substantial proportion of infectious disease morbidity and mortality, especially in children. The long-term goal of this project is to describe the human virome in children and to investigate its relevance to febrile illnesses in children. The project will also seek to understand the relationship of the immune system to the composition of the virome. Thus, the project's specific aims are 1) To elucidate the spectrum of viruses that can be detected using non-biased, high throughput sequencing on samples of blood, respiratory, and gastrointestinal secretions from healthy children and to use this information as a basis for understanding the role of viruses in acute febrile illnesses without an obvious source, and 2) to investigate the effect of various forms of immunosuppression on the spectrum of viruses detected in children, and to use this information as a basis for understanding the role of viruses in acute febrile illnesses occurring in these children. Our preliminary studies show that diverse viruses can be detected in children having undiagnosed fever. To carry out the specific aims, well children will be enrolled prior to having elective surgery, and febrile otherwise well children will be enrolled from the Emergency Department at St. Louis Children's Hospital. Immunocompromised children will be recruited from hematopoietic stem cell and solid organ transplant clinics, the HIV/AIDS clinic, and the rheumatology/immunology clinic from the same hospital. Children with fever will have samples obtained at the time of the febrile illness and at 1 and 6-month follow-up visits. Selected samples from each study group will be analyzed at the Genome Center at Washington University (GCWU) using next generation 454 high throughput sequencing to detect and sequence all viral sequences present. We anticipate detecting and sequencing a broad range of viruses, including previously unrecognized agents. A variety of techniques will be used to investigate the significance of viruses detected. Virus-specific PCR assays will be used to determine the frequency and extent of viruses detected by sequencing, using the full range of samples collected. Host response to the detected viruses will be investigated using serologic analysis, cytokine profiling, and microarrays to characterize host gene expression. These studies will take advantage of follow-up samples to compare the acute response with the response in the convalescent period. This study will draw upon the expertise and technological assets of one of the world's most powerful sequencing centers to provide the research community with a comprehensive sequence data base of the viruses that are present in children, which can be used to improve our understanding of the causes of febrile illnesses in young children, many of which are currently undiagnosed.</p>
Project description:Contributions of the viral component of the microbiome, the virome, to the development of innate and adaptive immunity are largely unknown. In this study, we systematically defined the tissue host response to a panel of eukaryotic enteric viruses inducing asymptomatic infection in mice. Small intestinal and colon transcriptomes from GF mice were compared to the ones from germ-free mice mono-infected with each of the viruses in the panel. This transcriptional profiling unveiled general adaptations by the host as well as numerous viral strain-specific responses that persist.
Project description:Zoonotic influenza A viruses of avian origin can cause severe disease in individuals, or even global pandemics, and thus pose a threat to human populations. Waterfowl and shorebirds are believed to be the reservoir for all influenza A viruses, but this has recently been challenged by the identification of novel influenza A viruses in bats. The major bat influenza A virus envelope glycoprotein, haemagglutinin, does not bind the canonical influenza A virus receptor, sialic acid or any other glycan, despite its high sequence and structural homology with conventional haemagglutinins. This functionally uncharacterized plasticity of the bat influenza A virus haemagglutinin means the tropism and zoonotic potential of these viruses has not been fully determined. Here we show, using transcriptomic profiling of susceptible versus non-susceptible cells in combination with genome-wide CRISPR-Cas9 screening, that the major histocompatibility complex class II (MHC-II) human leukocyte antigen DR isotype (HLA-DR) is an essential entry determinant for bat influenza A viruses. Genetic ablation of the HLA-DR α-chain rendered cells resistant to infection by bat influenza A virus, whereas ectopic expression of the HLA-DR complex in non-susceptible cells conferred susceptibility. Expression of MHC-II from different bat species, pigs, mice or chickens also conferred susceptibility to infection. Notably, the infection of mice with bat influenza A virus resulted in robust virus replication in the upper respiratory tract, whereas mice deficient for MHC-II were resistant. Collectively, our data identify MHC-II as a crucial entry mediator for bat influenza A viruses in multiple species, which permits a broad vertebrate tropism.
Project description:The gastrointestinal ecosystem is a highly complex environment with a profound influence on human health. Inflammation in the gut, linked to an altered gut microbiome has been associated with the development of multiple human conditions including type 1 diabetes (T1D). Viruses infecting the gastrointestinal tract, especially enteroviruses, are also thought to play an important role in T1D pathogenesis possibly via overlapping mechanisms. Here, we apply an integrative approach to combine comprehensive faecal virome, microbiome and metaproteome data sampled before and at the onset of islet autoimmunity in 40 children. We show strong age and antibody related effects across the datasets. Mastadenovirus infection was associated with profound functional changes in the faecal metaproteome. Multiomic factor analysis modelling revealed proteins associated with carbohydrate transport from the genus Faecalibacterium were associated with islet autoimmunity. These findings demonstrate functional remodelling of the gut microbiota accompanies both islet autoimmunity and viral infection.
Project description:Pairwise compatibility between virus and host proteins can dictate the outcome of infection. During transmission, both inter- and intraspecies variabilities in receptor protein sequences can impact cell susceptibility. Many viruses possess mutable viral entry proteins and the patterns of host compatibility can shift as the viral protein sequence changes. This combinatorial sequence space between virus and host is poorly understood, as traditional experimental approaches lack the throughput to simultaneously test all possible combinations of protein sequences. Here, we created a pseudotyped virus infection assay where a multiplexed target-cell library of host receptor variants can be assayed simultaneously using a DNA barcode sequencing readout. We applied this assay to test a panel of 30 ACE2 orthologs or human sequence mutants for infectability by the original SARS-CoV-2 spike protein or the Alpha, Beta, Gamma, Delta, and Omicron BA1 variant spikes. We compared these results to an analysis of the structural shifts that occurred for each variant spike’s interface with human ACE2. Mutated residues were directly involved in the largest shifts, although there were also widespread indirect effects altering interface structure. The N501Y substitution in spike conferred a large structural shift for interaction with ACE2, which was partially recreated by indirect distal substitutions in Delta, which does not harbor N501Y. The structural shifts from N501Y greatly influenced the set of animal orthologs the variant spike was capable of interacting with. Out of the thirteen non-human orthologs, ten exhibited unique patterns of variant-specific compatibility, demonstrating that spike sequence changes during human transmission can toggle ACE2 compatibility and potential susceptibility of other animal species, and cumulatively increase overall compatibilities as new variants emerge. These experiments provide a blueprint for similar large-scale assessments of protein compatibility during entry by diverse viruses. This dataset demonstrates the complex compatibility relationships that occur between variable interacting host and virus proteins.