Zhou Duanfang, Li Xiaoli, Xiao Xiaoqiu, Wang Gang, Chen Bo, Song Yi, Liu Xu, He Qichen, Zhang Huan, Wu Qiuya, Zhang Limei, Wu Lihong, Shen Zhengze, Hassan Moustapha, Zhao Ying, Zhou Weiying
Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China; Department of pharmacy, Women and Children's Hospital of Chongqing Medical University, Chongqing, China.
Department of Pharmacology, College of Pharmacy, Chongqing Medical University, Chongqing, China; Chongqing Key Laboratory of Drug Metabolism, Chongqing, China; Key laboratory for Biochemistry and Molecular Pharmacology of Chongqing, Chongqing, China.
Phytomedicine. 2023 Feb;110:154634. doi: 10.1016/j.phymed.2022.154634. Epub 2022 Dec 27.
Thioredoxin-interacting protein (TXNIP) plays a pivotal role in regulation of blood glucose homeostasis and is an emerging therapeutic target in diabetes and its complications. Celastrol, a pentacyclic triterpene extracted from the roots of Tripterygium wilfordii Hook F, can reduce insulin resistance and improve diabetic complications.
This study aimed to untangle the mechanism of celastrol in ameliorating type 2 diabetes (T2DM) and evaluate its potential benefits as an anti-diabetic agent.
db/db mice was used to evaluate the hypoglycemic effect of celastrol in vivo; Enzyme-linked immunosorbent assay (ELISA) and 2-NBDG assay were used to detect the effect of celastrol on insulin secretion and glucose uptake in cells; Western blotting, quantitative reverse transcription PCR (RT-qPCR) and immunohistological staining were used to examine effect of celastrol on the expression of TXNIP and the carbohydrate response element-binding protein (ChREBP). Molecular docking, cellular thermal shift assay (CETSA), drug affinity responsive targets stability assay (DARTS) and mass spectrometry were used to test the direct binding between celastrol and ChREBP. Loss- and gain-of-function studies further confirmed the role of ChREBP and TXNIP in celastrol-mediated amelioration of T2DM.
Celastrol treatment significantly reduced blood glucose level, body weight and food intake, and improved glucose tolerance in db/db mice. Moreover, celastrol promoted insulin secretion and improved glucose homeostasis. Mechanistically, celastrol directly bound to ChREBP, a primary transcriptional factor upregulating TXNIP expression. By binding to ChREBP, celastrol inhibited its nuclear translocation and promoted its proteasomal degradation, thereby repressing TXNIP transcription and ultimately ameliorating T2DM through breaking the vicious cycle of hyperglycemia deterioration and TXNIP overexpression.
Celastrol ameliorates T2DM through targeting ChREBP-TXNIP aix. Our study identified ChREBP as a new direct molecular target of celastrol and revealed a novel mechanism for celastrol-mediated amelioration of T2DM, which provides experimental evidence for its possible use in the treatment of T2DM and new insight into diabetes drug development for targeting TXNIP.
硫氧还蛋白相互作用蛋白（TXNIP）在血糖稳态调节中起关键作用，是糖尿病及其并发症中一个新兴的治疗靶点。雷公藤红素是从雷公藤根中提取的一种五环三萜，可降低胰岛素抵抗并改善糖尿病并发症。
本研究旨在阐明雷公藤红素改善2型糖尿病（T2DM）的机制，并评估其作为抗糖尿病药物的潜在益处。
使用db/db小鼠评估雷公藤红素在体内的降血糖作用；采用酶联免疫吸附测定（ELISA）和2-NBDG测定法检测雷公藤红素对细胞胰岛素分泌和葡萄糖摄取的影响；运用蛋白质免疫印迹法、定量逆转录聚合酶链反应（RT-qPCR）和免疫组织化学染色法检测雷公藤红素对TXNIP和碳水化合物反应元件结合蛋白（ChREBP）表达的影响。采用分子对接、细胞热位移分析（CETSA）、药物亲和力响应靶点稳定性分析（DARTS）和质谱法检测雷公藤红素与ChREBP之间的直接结合。功能缺失和功能获得研究进一步证实了ChREBP和TXNIP在雷公藤红素介导的T2DM改善中的作用。
雷公藤红素治疗显著降低了db/db小鼠的血糖水平、体重和食物摄入量，并改善了葡萄糖耐量。此外，雷公藤红素促进胰岛素分泌并改善葡萄糖稳态。机制上，雷公藤红素直接与ChREBP结合，ChREBP是上调TXNIP表达的主要转录因子。通过与ChREBP结合，雷公藤红素抑制其核转位并促进其蛋白酶体降解，从而抑制TXNIP转录，最终通过打破高血糖恶化和TXNIP过表达的恶性循环来改善T2DM。
雷公藤红素通过靶向ChREBP-TXNIP轴改善T2DM。我们的研究确定ChREBP是雷公藤红素的一个新的直接分子靶点，并揭示了雷公藤红素介导的T2DM改善的新机制，为其可能用于治疗T2DM提供了实验证据，并为靶向TXNIP的糖尿病药物开发提供了新的见解。
