OP32 The gut virome-colonizing Orthohepadnavirus genus is associated with ulcerative colitis pathogenesis and induces intestinal inflammation in vivo
Facoetti, A.(1)*;Massimino, L.(2);Palmieri, O.(3);Fuggetta , D.(1);Spanò , S.(2);D'Alessio , S.(4);Furfaro, F.(5);D'Amico, F.(5);ZIlli, A.(5);Fiorino, G.(5);Noviello, D.(6);Latiano, A.(3);Bossa, F.(3);Pirola, A.(7);Mologni, L.(8);Piazza, R.(8);Abbati, D.(9);Perri, F.(3);Bonini , C.(9);Peyrin-Biroulet, L.(10);Malesci, A.(5);Danese, S.(5);Ungaro, F.(2);
(1)Università Vita-Salute San Raffaele, Department of Gastroenterology and Digestive Endoscopy in the Laboratory of Experimental Gastroenterology, Milan, Italy;(2)IRCCS Ospedale San Raffaele, Department of Gastroenterology and Digestive Endoscopy in the Laboratory of Experimental Gastroenterology, Milan, Italy;(3)Fondazione IRCCS Casa Sollievo della Sofferenza, Division of Gastroenterology, San Giovanni Rotondo FG, Italy;(4)Phoenix Lab, none, Lody, Italy;(5)IRCCS Ospedale San Raffaele, Department of Gastroenterology and Digestive Endcoscopy, Milan, Italy;(6)University of Milan, Department of Pathophysiology and Transplantation, Milan, Italy;(7)Galseq, None, Milan, Italy;(8)University of Milano - Bicocca, Department of Medicine and Surgery, Monza, Italy;(9)IRCCS Ospedale San Raffaele, Division of Immunology- Transplantation and Infectious Disease, Milan, Italy;(10)Inserm NGERE, University of Lorraine, Nancy, France;
Background
Ulcerative colitis (UC) is a chronic inflammatory disorder with an unknown etiology1. Over recent years, a growing body of evidence has been pinpointing gut virome dysbiosis as a fundamental component in its progression2, although its role during the early phases of chronic inflammation is far from being fully defined. Therefore, we sought to investigate the role of a virome-associated protein encoded by the Orthohepadnavirus genus, the Hepatitis B virus X protein (HBx)3, during UC aetiopathogenesis.
Methods
HBx positivity of UC patient-derived blood and gut mucosa was assessed by RT-PCR and Sanger sequencing correlated with clinical characteristics by multivariate analysis. Transcriptomics was performed on HBx-overexpressing endoscopic biopsies from healthy donors.
C57BL/6 mice underwent intramucosal injections of liposome-conjugated HBx-encoding plasmids or the control. Multidimensional flow cytometry analysis was performed on colonic samples from HBx-treated and control animals. Transepithelial electrical resistance measurement, proliferation assay, ChIP-Seq, and RNA-Seq were performed on in vitro models of the gut barrier.
Results
HBx was detected in about 45% of patients with UC (Figure 1) and found to induce colonic inflammation in mice (Figure 2A-2D), while its silencing reverted the colitis phenotype in vivo (Figure 2E-2H). HBx acts as a transcriptional regulator in epithelial cells (Figure 3), provoking barrier leakage and altering inflammatory response (Figures 3 and 4).
Conclusion
This study paves the way for the understanding of the aetiopathogenesis of UC and provides a brand-new standpoint that looks at the virome as a target for tailored treatments, possibly leading to an entirely new approach to therapeutic intervention.
References
1. Massimino L, Lamparelli LA, Houshyar Y, et al. The Inflammatory Bowel Disease Transcriptome and Metatranscriptome Meta-Analysis (IBD TaMMA) framework. Nat Comput Sci 2021;1:511–5. doi:10.1038/s43588-021-00114-y
2.Ungaro F, Massimino L, D’Alessio S, et al. The gut virome in inflammatory bowel disease pathogenesis: From metagenomics to novel therapeutic approaches. United European Gastroenterol J 2019;7:999–1007. doi:10.1177/2050640619876787
3.Ungaro F, Massimino L, Furfaro F, et al. Metagenomic analysis of intestinal mucosa revealed a specific eukaryotic gut virome signature in early-diagnosed inflammatory bowel disease. Gut Microbes 2019;10:149–58. doi:10.1080/19490976.2018.1511664