Role of Gut Bacterial Side-Chain Cleavage of Cortisol in Host 11Beta-Hydroxyandrostenedione Formation

内分泌学文献中关于前雄激素11β-受体的生物合成存在重大争议。 羟基雄烯二酮（11β-OHAD）。11β-OHAD的合成被认为主要是在 肾上腺通过雄烯二酮的11β-羟基化（A4）。另一种途径是通过侧链裂解 皮质醇，虽然它被认为是轻微的。17-羟化酶/C17，20-裂解酶（CYP 17 A1）缺乏症患者 无法合成皮质醇或A4。当外源性给予皮质醇时，尿液特征表现出衍生物 11β-OHAD这表明，要么是一种新的宿主酶，要么是一种肠道微生物酶负责侧链 皮质醇裂解。我们已经确定了一个高度活跃的肠道微生物途径中的基因， 皮质醇的侧链断裂我们假设肠道微生物群是一个重要的， 它是宿主内分泌系统的组成部分，产生大量的11β-OHAD。该项目将 通过比较无菌猪和定居猪的稳定同位素标记皮质醇代谢来验证这一假设 肠道微生物组的复杂程度不同。我们将通过单- 细胞RNA-Seq、免疫组织化学和免疫细胞的流式细胞术。了解生理作用 侧链裂解的肠道细菌也是重要的，在确定未来的战略，以调节前， 雄激素形成我们将在体外确定细菌对皮质醇和11β-OHAD的转录组反应 和体内。此外，为了证明皮质醇侧链基因之间的因果关系， 切割（desAB）和宿主类固醇代谢组学概况，我们将利用合成生物学方法来工程化 desAB途径（野生型和失活突变体）进入E.大肠杆菌，并定殖于无菌猪。这些 这些研究有望解决一个存在了几十年的谜团，如果它能 可以表明，肠道微生物群对定量的主要宿主类固醇和促激素有显著贡献。 雄激素

A major controversy exists in the endocrinology literature regarding the biosynthesis of the pro-androgen 11β- hydroxyandrostenedione (11β-OHAD). The synthesis of 11β-OHAD is thought mainly to be synthesized in the adrenal gland by 11β-hydroxylation of androstenedione (A4). Another route is through the side-chain cleavage of cortisol, although it is thought to be minor. Patients with 17-hydroxylase/C17,20-lyase (CYP17A1) deficiency fail to synthesize either cortisol or A4. When given cortisol exogenously, the urinary profile exhibits derivatives of 11β-OHAD. This suggests either a novel host enzyme, or a gut microbial enzyme responsible for side-chain cleavage of cortisol. We have identified genes in a highly active gut microbial pathway that may be responsible for the side-chain cleavage of cortisol. We hypothesize that gut microbiota are an important, and understudied component of the host endocrine system, which generate significant quantities of 11β-OHAD. This project will test this hypothesis by comparing stable isotope-labeled cortisol metabolism in germ-free pigs and pigs colonized with gut microbiomes of different complexity. We will determine effects on host colonic physiology through single- cell RNA-Seq, immunohistochemistry, and flow cytometry of immune cells. Understanding the physiological role of side-chain cleavage by gut bacteria is also important in determining future strategies to modulate pro- androgen formation. We will determine bacterial transcriptomic responses to cortisol and 11β-OHAD both in vitro and in vivo. Furthermore, to demonstrate causation between the genes responsible for cortisol side-chain cleavage (desAB) and host steroid metabolome profile, we will utilize a synthetic biology approach to engineer the desAB pathway (both wild type and inactive mutant) into E. coli and colonize the gnotobiotic pigs. These studies are expected to resolve an enigma that has existed for decades, and may result in a paradigm-shift if it can be shown that the gut microbiota contributes significantly to a quantitatively major host steroid and pro- androgen.