Huang Yong

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  • Preprint
    Insights into the pathogenesis of ulcerative colitis from a murine model of stasis-induced dysbiosis, colonic metaplasia, and genetic susceptibility
    ( 2016-04) Ward, Marc A. ; Pierre, Joseph F. ; Leal, Raquel F. ; Huang, Yong ; Shogan, Benjamin ; Dalal, Sushila R. ; Weber, Christopher R. ; Leone, Vanessa A. ; Musch, Mark W. ; An, Gary C. ; Rao, Mrinalini C. ; Rubin, David ; Raffals, Laura E. ; Antonopoulos, Dionysios A. ; Sogin, Mitchell L. ; Hyman, Neil H. ; Alverdy, John C. ; Chang, Eugene B.
    Gut dysbiosis, host genetics, and environmental triggers are implicated as causative factors in inflammatory bowel disease (IBD), yet mechanistic insights are lacking. Longitudinal analysis of ulcerative colitis patients following total colectomy with ileal anal anastomosis (IPAA) where >50% develop pouchitis, offers a unique setting to examine cause vs. effect. To recapitulate human IPAA, we employed a mouse model of surgically created blind self-filling (SFL) and self- emptying (SEL) ileal loops using wild-type (WT), IL-10 KO (IL10), and TLR4 KO (T4), and IL10/T4 double KO mice. After 5 weeks, loop histology, host gene/protein expression, and bacterial 16s rRNA profiles were examined. SFL exhibit fecal stasis due to directional motility oriented towards the loop end, whereas SEL remain empty. In wild type mice, SFL, but not SEL, develop pouch-like microbial communities without accompanying active inflammation. However, in genetically susceptible IL-10-/- deficient mice, SFL, but not SEL, exhibit severe inflammation and mucosal transcriptomes resembling human pouchitis. The inflammation associated with IL- 10-/- required TLR4, as animals lacking both pathways displayed little disease. Furthermore, germ-free IL10-/- mice conventionalized with SFL, but not SEL, microbiota populations develop severe colitis. These data support essential roles of stasis-induced, colon-like microbiota, TLR4- mediated colonic metaplasia, and genetic susceptibility in the development of pouchitis and possibly UC. However, these factors by themselves are not sufficient. Similarities between this model and human UC/pouchitis provide opportunities for gaining insights into the mechanistic basis of IBD and for identification of targets for novel preventative and therapeutic interventions.
  • Article
    Identification of cinnabarinic acid as novel endogenous aryl hydrocarbon receptor ligand that drives IL-22 production
    (Public Library of Science, 2014-02-03) Lowe, Margaret M. ; Mold, Jeff E. ; Kanwar, Bittoo ; Huang, Yong ; Louie, Alexander ; Pollastri, Michael P. ; Wang, Cuihua ; Patel, Gautam ; Franks, Diana G. ; Schlezinger, Jennifer ; Sherr, David H. ; Silverstone, Allen E. ; Hahn, Mark E. ; McCune, Joseph M.
    The aryl hydrocarbon receptor (AHR) binds to environmental toxicants including synthetic halogenated aromatic hydrocarbons and is involved in a diverse array of biological processes. Recently, the AHR was shown to control host immunity by affecting the balance between inflammatory T cells that produce IL-17 (Th17) and IL-22 versus regulatory T cells (Treg) involved in tolerance. While environmental AHR ligands can mediate this effect, endogenous ligands are likely to be more relevant in host immune responses. We investigated downstream metabolites of tryptophan as potential AHR ligands because (1) tryptophan metabolites have been implicated in regulating the balance between Th17 and Treg cells and (2) many of the AHR ligands identified thus far are derivatives of tryptophan. We characterized the ability of tryptophan metabolites to bind and activate the AHR and to increase IL-22 production in human T cells. We report that the tryptophan metabolite, cinnabarinic acid (CA), is an AHR ligand that stimulates the differentiation of human and mouse T cells producing IL-22. We compare the IL-22-stimulating activity of CA to that of other tryptophan metabolites and define stimulation conditions that lead to CA production from immune cells. Our findings link tryptophan metabolism to AHR activation and define a novel endogenous AHR agonist with potentially broad biological functions.