bioRxiv Science⌕ Search

Biology subjects

Metwaly, A.

Publications and source records attributed to Metwaly, A..

2 recordsLinked to original sources

A translational swine model for Crohn`s disease

Crohns Disease (CD) is incurable, and represents a lifelong burden for patients and its incidence is increasing worldwide. A key contributing factor is a dysregulated immune response. Here we report the generation of genome edited pigs with a deletion of the transcript-destabilizing AU-rich element (ARE) and a constitutive decay element (CDE) in the TNF gene which recapitulate major characteristics of human CD, including ulcerative transmural ileocolitis, increased abundance of proinflammatory cytokines, evidence for impaired integrity of the intestinal epithelial cell barrier, immune cell infiltration, and dysbiotic microbial communities. This physiologically relevant CD model enables human-scale and long-term studies to assess diagnostic, nutritional or microbial interventions, filling the gap for translating findings into the clinic.

bioengineering↗

Diet prevents the expansion of segmented filamentous bacteria and ileo-colonic inflammation in a model of Crohn's disease

Crohns disease (CD) is associated with changes in the microbiota, and murine models of CD-like ileo-colonic inflammation depend on the presence of microbial triggers. Increased abundance of unknown Clostridiales and the microscopic detection of filamentous structures close to the epithelium of Tnf {Delta}ARE mice pointed towards segmented filamentous bacteria (SFB), a commensal well-known to induce the maturation of Th17 cell-derived immune responses that is highly implicated in the pathogenesis of IBD. We show that the abundance of SFB strongly correlates with the severity of CD-like ileal inflammation in Tnf {Delta}ARE and SAMP/Yit mice. SFB mono-colonization of germ-free Tnf {Delta}ARE mice confirmed the causal link and resulted in severe ileo-colonic inflammation, characterized by elevated tissue levels of Tnf and Il-17, neutrophil infiltration and loss of Paneth and goblet cell function. Co-colonization of SFB in human-microbiota associated Tnf {Delta}ARE mice confirmed that SFB presence is indispensable for disease development. Screening of 412 ileal and colonic mucosal biopsies from IBD patients using previously published and newly designed human SFB-specific primer sets showed no presence of SFB in human tissue samples. Simulating the protective effect of exclusive enteral nutrition (EEN) by feeding SFB mono-colonized Tnf {Delta}ARE mice EEN-like purified diet antagonized SFB colonization and prevented disease development in Tnf {Delta}ARE mice, clearly demonstrating the important role of diet in modulating this IBD-related but murine pathobiont.

microbiology↗