DataSheet_1_Cytochrome P450 1A1 is essential for the microbial metabolite, Urolithin A-mediated protection against colitis.pdf

BackgroundCytochrome P450 Family 1 Subfamily A Member 1 (CYP1A1) pathway, which is regulated by aryl hydrocarbon receptor (AhR) plays an important role in chemical carcinogenesis and xenobiotic metabolism. Recently, we demonstrated that the microbial metabolite Urolithin A (UroA) mitigates colitis through its gut barrier protective and anti-inflammatory activities in an AhR-dependent manner. Here, we explored role of CYP1A1 in UroA-mediated gut barrier and immune functions in regulation of inflammatory bowel disease (IBD).
MethodsTo determine the role of CYP1A1 in UroA-mediated protectives activities against colitis, we subjected C57BL/6 mice and Cyp1a1-/- mice to dextran sodium sulphate (DSS)-induced acute colitis model. The phenotypes of the mice were characterized by determining loss of body weight, intestinal permeability, systemic and colonic inflammation. Further, we evaluated the impact of UroA on regulation of immune cell populations by flow cytometry and confocal imaging using both in vivo and ex vivo model systems.
ResultsUroA treatment mitigated DSS-induced acute colitis in the wildtype mice. However, UroA-failed to protect Cyp1a1-/- mice against colitis, as evident from non-recovery of body weight loss, shortened colon lengths and colon weight/length ratios. Further, UroA failed to reduce DSS-induced inflammation, intestinal permeability and upregulate tight junction proteins in Cyp1a1-/- mice. Interestingly, UroA induced the expansion of T-reg cells in a CYP1A1-dependent manner both in vivo and ex vivo models.
ConclusionOur results suggest that CYP1A1 expression is essential for UroA-mediated enhanced gut barrier functions and protective activities against colitis. We postulate that CYP1A1 plays critical and yet unknown functions beyond xenobiotic metabolism in the regulation of gut epithelial integrity and immune systems to maintain gut homeostasis in IBD pathogenesis.

背景：细胞色素P450家族1亚家族A成员1（Cytochrome P450 Family 1 Subfamily A Member 1，CYP1A1）通路受芳烃受体（aryl hydrocarbon receptor，AhR）调控，在化学致癌作用与外源性物质代谢中发挥关键作用。本团队前期已证实，微生物代谢产物尿石素A（Urolithin A，UroA）可通过AhR依赖的途径发挥肠道屏障保护与抗炎活性，进而缓解结肠炎。本研究旨在探究CYP1A1在UroA介导的肠道屏障与免疫功能调控，以及炎症性肠病（inflammatory bowel disease，IBD）发病过程中的作用。
方法：为明确CYP1A1在UroA抗结肠炎保护活性中的功能，我们将C57BL/6野生型小鼠与Cyp1a1基因敲除（Cyp1a1-/-）小鼠构建右旋糖酐硫酸钠（dextran sodium sulphate，DSS）诱导的急性结肠炎模型。通过检测小鼠体重丢失情况、肠道通透性、全身与结肠炎症水平，对小鼠表型进行全面表征。此外，我们分别利用体内与离体模型系统，通过流式细胞术与共聚焦成像技术，评估UroA对免疫细胞群的调控效应。
结果：UroA处理可缓解野生型小鼠体内DSS诱导的急性结肠炎。然而，UroA无法对Cyp1a1-/-小鼠提供结肠炎保护作用，该现象可从体重丢失未得到恢复、结肠长度缩短以及结肠重量/长度比值异常得到证实。进一步实验显示，UroA无法降低Cyp1a1-/-小鼠中DSS诱导的炎症与肠道通透性，也无法上调紧密连接蛋白的表达。值得注意的是，在体内与离体模型中，UroA均可通过依赖CYP1A1的方式诱导调节性T细胞（T-reg细胞）的扩增。
结论：本研究结果表明，CYP1A1的表达对于UroA介导的肠道屏障功能增强与抗结肠炎保护活性至关重要。我们推测，在炎症性肠病的发病进程中，CYP1A1在维持肠道稳态的肠道上皮完整性与免疫系统调控中，发挥着超越外源性物质代谢的关键且尚未被阐明的生物学功能。