Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
Mol Cell Biol. 2018 Mar 15;38(7). doi: 10.1128/MCB.00654-17. Print 2018 Apr 1.
The cholesterol sulfotransferase SULT2B1b converts cholesterol to cholesterol sulfate (CS). We previously reported that SULT2B1b inhibits hepatic gluconeogenesis by antagonizing the gluconeogenic activity of hepatocyte nuclear factor 4α (HNF4α). In this study, we showed that the SULT2B1b gene is a transcriptional target of HNF4α, which led to our hypothesis that the induction of SULT2B1b by HNF4α represents a negative feedback to limit the gluconeogenic activity of HNF4α. Indeed, downregulation of Sult2B1b enhanced the gluconeogenic activity of HNF4α, which may have been accounted for by the increased acetylation of HNF4α as a result of decreased expression of the HNF4α deacetylase sirtuin 1 (Sirt1). The expression of Sult2B1b was also induced by HNF4α upon fasting, and the Sult2B1b null (Sult2B1b) mice showed increased gluconeogenic gene expression and an elevated fasting glucose level, suggesting that SULT2B1b also plays a restrictive role in HNF4α-mediated fasting-responsive gluconeogenesis. We also developed thiocholesterol, a hydrolysis-resistant derivative of CS, which showed superior activity to that of the native CS in inhibiting gluconeogenesis and improving insulin sensitivity in high-fat-diet-induced diabetic mice. We conclude that the HNF4α-SULT2B1b-CS axis represents a key endogenous mechanism to prevent uncontrolled gluconeogenesis. Thiocholesterol may be used as a therapeutic agent to manage hyperglycemia.
胆固醇硫酸转移酶 SULT2B1b 将胆固醇转化为胆固醇硫酸酯(CS)。我们之前报道过,SULT2B1b 通过拮抗肝细胞核因子 4α(HNF4α)的糖异生活性来抑制肝糖异生。在这项研究中,我们表明 SULT2B1b 基因是 HNF4α 的转录靶标,这导致我们假设 HNF4α 诱导 SULT2B1b 代表一种负反馈,以限制 HNF4α 的糖异生活性。事实上,下调 Sult2B1b 增强了 HNF4α 的糖异生活性,这可能是由于 HNF4α 去乙酰化酶 Sirtuin 1(Sirt1)表达减少导致 HNF4α 乙酰化增加所致。禁食也会诱导 Sult2B1b 的表达,而 Sult2B1b 缺失(Sult2B1b)小鼠表现出增加的糖异生基因表达和升高的空腹血糖水平,表明 SULT2B1b 也在 HNF4α 介导的禁食反应性糖异生中发挥限制作用。我们还开发了硫胆固醇,一种 CS 的水解抗性衍生物,它在抑制糖异生和改善高脂肪饮食诱导的糖尿病小鼠胰岛素敏感性方面的活性优于天然 CS。我们得出结论,HNF4α-SULT2B1b-CS 轴代表了防止失控性糖异生的关键内源性机制。硫胆固醇可能被用作治疗高血糖的药物。