Bile acids are steroids formed at the interface of host metabolism and intestinal microbiota. While primary bile acids are generated in the liver from cholesterol metabolism, secondary bile acids represent the products of microbial enzymes. Close to 100 different enzymatic modifications of bile acids structures occur in the human intestine and clinically guided metagenomic and metabolomic analyses have led to the identification of an extraordinary number of novel metabolites. These chemical mediators make an essential contribution to the composition and function of the postbiota, participating to the bidirectional communications of the intestinal microbiota with the host and contributing to the architecture of intestinal-liver and -brain and -endocrine axes. Bile acids exert their function by binding to a group of cell membrane and nuclear receptors collectively known as bile acid-regulated receptors (BARRs), expressed in monocytes, tissue-resident macrophages, CD4+ T effector cells, including Th17, T regulatory cells, dendritic cells and type 3 of intestinal lymphoid cells and NKT cells, highlighting their role in immune regulation. In this review we report on how bile acids and their metabolitesmodulate the immune system in inflammations and cancers and could be exploiting for developing novel therapeutic approaches in these disorders.

中文翻译：

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胆汁酸调节受体的免疫学


胆汁酸是在宿主代谢和肠道微生物群界面形成的类固醇。初级胆汁酸是在肝脏中通过胆固醇代谢产生的，而次级胆汁酸则代表微生物酶的产物。人类肠道中发生了近 100 种不同的胆汁酸结构酶促修饰，临床指导的宏基因组和代谢组分析已鉴定出大量新型代谢物。这些化学介质对后生物群的组成和功能做出了重要贡献，参与肠道微生物群与宿主的双向通讯，并有助于肠-肝、脑和内分泌轴的结构。胆汁酸通过与一组统称为胆汁酸调节受体 (BARR) 的细胞膜和核受体结合来发挥其功能，这些受体在单核细胞、组织驻留巨噬细胞、CD4+ T 效应细胞（包括 Th17、T 调节细胞、树突状细胞）中表达细胞以及肠淋巴细胞和 NKT 细胞的 3 型，突出了它们在免疫调节中的作用。在这篇综述中，我们报告了胆汁酸及其代谢物如何调节炎症和癌症中的免疫系统，并可用于开发这些疾病的新治疗方法。