Mitochondrial perturbation in the intestine causes microbiota-dependent injury and gene signatures discriminative of inflammatory disease

Abstract

Mitochondrial dysfunction is associated with inflammatory bowel diseases (IBDs). To understand how microbial-metabolic circuits contribute to intestinal injury, we disrupt mitochondrial function in the epithelium by deleting the mitochondrial chaperone, heat shock protein 60 (Hsp60^Δ/ΔIEC). This metabolic perturbation causes self-resolving tissue injury. Regeneration is disrupted in the absence of the aryl hydrocarbon receptor (Hsp60^Δ/ΔIEC;AhR^-/-) involved in intestinal homeostasis or inflammatory regulator interleukin (IL)-10 (Hsp60^Δ/ΔIEC;Il10^-/-), causing IBD-like pathology. Injury is absent in the distal colon of germ-free (GF) Hsp60^Δ/ΔIEC mice, highlighting bacterial control of metabolic injury. Colonizing GF Hsp60^Δ/ΔIEC mice with the synthetic community OMM¹² reveals expansion of metabolically flexible Bacteroides, and B. caecimuris mono-colonization recapitulates the injury. Transcriptional profiling of the metabolically impaired epithelium reveals gene signatures involved in oxidative stress (Ido1, Nos2, Duox2). These signatures are observed in samples from Crohn's disease patients, distinguishing active from inactive inflammation. Thus, mitochondrial perturbation of the epithelium causes microbiota-dependent injury with discriminative inflammatory gene profiles relevant for IBD.

Keywords: Bacteroides; IBD; cell stress; heat shock protein 60; inflammation; intestinal epithelial cells; metabolic injury; microbiome; mitochondrial dysfunction; unfolded protein response.