Nat E. Zhou Rongbin/Jiang Wei/Zhu Shu cooperation reveals the role and mechanism of intestinal symbiotic virus in maintaining the immune stability of the intestinal mucosa.

A large number of symbiotic microorganisms, including bacteria, viruses and fungi, exist in human intestine, lungs, skin and other tissues.in recent years, studies have shown that intestinal symbionts not only participate in the regulation of intestinal immune system development, differentiation and function, but also play an important role in the occurrence of a variety of diseases [1].although the metagenome sequencing analysis showed that a large number of DNA and RNA viruses were colonized in the intestines of healthy people and animals [2-5], and the disorder of enterovirus group was also reported to be closely related to intestinal inflammatory diseases [6,7].however, there is a lack of research on the pathological and physiological functions of symbiotic viruses.on October 21, 2019, Professor Zhou Rongbin / Jiang Wei / Zhu Shu, University of science and technology of China, published a research paper entitled "commercial viruses maintain intellectual intraepithelial lymphocytes via noncanonic RIG-I signaling" in Nature Immunology.this study is the first to discover that enterosymbiosis virus plays an important role in maintaining the homeostasis of intestinal intraepithelial lymphocytes (IELs) under physiological conditions, and reveals the cellular and molecular mechanisms of its role.as the first line of defense of intestinal mucosal immunity, intestinal intraepithelial lymphocytes (IELs) play an important role in maintaining intestinal mucosal balance.the team first used metagenomic sequencing to confirm the presence of a large number of symbiotic phages and eukaryotic viruses in the gut of SPF free mice.further use of multiple antiviral drugs (AVC) to eliminate enterosymbiotic virus, it was found that the number of intestinal intraepithelial lymphoid cells in AVC treated mice decreased significantly, which was mainly accompanied by the decrease of CD8 α β + TCR β + and CD8 α α + TCR β + cell subsets.at the same time, there was no significant change in the number and proportion of immune cells in spleen, liver and other organs.these results suggest that enterosymbiotic viruses are important for maintaining the homeostasis of IELs.subsequently, in order to explore how the enterosymbiotic virus is perceived and regulated by the body, researchers used a variety of innate immune recognition receptors and their downstream signal protein deficient mice to analyze the proportion and number of intestinal IELs cell subsets.it was found that the intestinal IELs of mice with intracellular RNA receptor RIG-I deficiency (ddx58 - / -) and its downstream Street protein Mavs - / -) were significantly reduced. The results were consistent with those of antiviral clearance mice, suggesting that enterosymbiosis virus can maintain the IELs homeostasis by activating RIG-I signal.subsequently, the researchers used bone marrow chimerism experiments and conditional deficient mice to verify that RIG-I signals on antigen-presenting cells in the lamina propria of the intestine participate in and maintain the homeostasis of IELs.further study found that intestinal flora disturbance caused by clearance of enterosymbiotic virus and lack of RIG-I had no effect on intestinal IELs.and rig-i-mavs induced the expression of IL-15 through the downstream type I interferon independent IRF1 signal, thus maintaining the survival and proliferation of intestinal intraepithelial lymphocytes.finally, it was found that the maintenance of homeostasis of intraepithelial lymphocytes by enterosymbiosis virus can inhibit intestinal tissue injury and inflammation. in conclusion, this study is the first to reveal the role of enterosymbiosis virus in the maintenance of intestinal immune homeostasis and elucidate the mechanism. this study suggests that the imbalance of enterosymbiotic virus may play an important role in enteritis, intestinal cancer and other diseases. original link: plate maker: xiaoxianzi references 1. Honda, K. & amp; Littman, D. R. te microbiology in infectious disease and inflammation.Annu . Rev. Immunol. 30, 759–795 (2012).2. Reyes, A. et al. Viruses in the faecal microbiota of monozygotic twins andtheir mothers. Nature 466, 334–338 (2010).3. Virgin, H. W. Te virome in mammalian physiology and disease. Cell157,142–150 (2014).4. Zhang, T. et al. RNA viral community in human feces: prevalence of plantpathogenic viruses. PLoS Biol. 4, e3 (2006).5. Kim, M.S., et al., Diversity andabundance of single-stranded DNA viruses in human feces. Appl EnvironMicrobiol, 2011. 77(22): p. 8062-70.6. Lepage, P., et al., Dysbiosis ininflammatory bowel disease: a role for bacteriophages? Gut, 2008. 57(3): p.424-5.7. Lopetuso, L.R., et al., Gut Virome andInflammatory Bowel Disease. Inflamm Bowel Dis, 2016. 22(7): p. 1708-12.