Circadian time-dependent effects of experimental colitis on theophylline disposition and toxicity

Background and purpose

Drug disposition undergoes significant alteration in patients with inflammatory bowel disease (IBD), yet circadian time-dependency of these changes remains largely unexplored. In this study, we aimed to determine the temporal effects of experimental colitis on drug disposition and toxicity.

Experimental Approach

RNA-sequencing was used to screen genes relevant to colitis induced by dextran sodium sulfate in mice. Liver microsomes and pharmacokinetic analysis were used to analyze the activity of key enzymes. Dual luciferase assays and chromatin immunoprecipitation (ChIP) were employed to elucidate regulatory mechanisms.

Key Results

RNA sequencing analysis revealed that colitis markedly influenced expression of cytochrome P450 (CYP) enzymes. Specifically, a substantial down-regulation of CYP1A2 and CYP2E1 was observed in livers of mice with colitis at Zeitgeber Time 8 (ZT8), with no significant changes detected at ZT20. At ZT8, the altered expression corresponded to diminished metabolism and enhanced incidence of hepato-cardiac toxicity of theophylline, a substrate specifically metabolized by these enzymes. A combination of assays, integrating liver-specific Bmal1 knockout and targeted activation of BMAL1 showed that dysregulation in CYP1A2 and CYP2E1 during colitis was attributable to perturbed BMAL1 functionality. Luciferase reporter and ChIP assays collectively substantiated the role of BMAL1 in regulating Cyp1a2 and Cyp2e1 transcription through its binding affinity to E-box-like sites.

Conclusion and implication

Our findings establish a strong link between colitis and chronopharmacology, shedding light on how IBD affects drug disposition and toxicity over time. This research provides a theoretical foundation for optimizing drug dosage in patients with IBD.