AUPHOS, A “FIRST-IN CLASS“ ORAL AGENT FOR CORRECTING METABOLIC DYSFUNCTION IN IBD

Mucosal repair is the goal of medical therapy in IBD. Prospective inception cohort pediatric studies suggest that suppression of mitochondrial genes lead to unfavorable clinical outcomes in ulcerative colitis (UC) and Crohn’s disease (CD). We posit that the inability to restore epithelial mitochondrial respiration impairs ulcer healing in IBD. In the current study, we tested whether a novel compound (AuPhos) that improves mitochondrial function promotes ulcer healing in IBD.

Biodistribution and pharmacokinectic (PK) studies were performed (6h, 12h, 24h) after single oral dose (25mg/kg) of AuPhos using C57/BL/6 (WT) mice. Mitochondrial uptake of AuPhos was determined by measuring gold content in normal colonocytes (NCM460) using graphite furnace atomic absorption spectroscopy. Oxygen consumption rate (OCR) in isolated crypt-IECs from AuPhos-fed WT mice were examined using high-resolution respirometry. The effect of AuPhos in colitis was tested in DSS (2%; 7d) WT (B6) mice. Disease activity index (DAI) (weight loss, diarrhea, and hematochezia), intestinal permeability (FITC-dextran), histological scoring and the frequency of fissioning crypts were determined throughout the 21d time course. Tissue mRNA levels for mitochondrial enzyme, cytokine, chemokine and intestinal stem cell (ISC) marker genes were assessed by RT-qPCR.

Biodistribution and PK studies revealed that higher levels of orally administered AuPhos in small intestine and colon tissue, with limited systemic absorption. AuPhos displayed a dose-dependent mitochondrial uptake in IEC where respirometry showed >30% increase in OCR after oral dosing in vivo. AuPhos treatment decreased DAI (**; p<0.01), histologic colitis scores D11-15 (*; p<0.05) and FITC-dextran permeability in DSS colitis mice. Notably, AuPhos increased fissioning crypt numbers near healing ulcers in DSS-colitis mice (**; p<0.01) while it reduced mRNA for pro-inflammatory cytokines/chemokines (IL-1β, IL-6, IFN-γ, IP10). AuPhos induced mRNA for ISC markers [Lgr4 (*; p<0.05), Lgr5, Lrig1 (***; p<0.001)] and mitochondrial complexes [mtCO1 (**; p<0.01) and COX2 (***; p<0.001)]. These findings suggest that AuPhos-induced mitochondrial respiration drives transcriptomic regulation of IEC genes involved in colitis ulcer healing.

Our data suggests that AuPhos compound improves ulcer healing under acute colitis conditions by increasing mucosal OxPHOS metabolism. Specifically, we find that AuPhos increases mitochondrial respiration-induced crypt fissioning and ulcer healing associated with reduced mucosal inflammation and increased barrier integrity. Overall, AuPhos may be an important “first-in class” oral therapeutic for correcting the metabolic dysfunction central to IBD pathogenesis.