Celastrol targets the ChREBP-TXNIP axis to ameliorates type 2 diabetes mellitus

Backgrounds: Thioredoxin-interacting protein (TXNIP) plays a pivotal role in regulation of blood glucose ho-meostasis and is an emerging therapeutic target in diabetes and its complications. Celastrol, a pentacyclic tri-terpene extracted from the roots of Tripterygium wilfordii Hook F, can reduce insulin resistance and improve diabetic complications.Purpose: 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.Methods: db/db mice was used to evaluate the hypoglycemic effect of celastrol in vivo; Enzyme-linked immu-nosorbent 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 immunohisto-logical 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 af-finity 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.Results: 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 ho-meostasis. 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 pro-teasomal degradation, thereby repressing TXNIP transcription and ultimately ameliorating T2DM through breaking the vicious cycle of hyperglycemia deterioration and TXNIP overexpression.Conclusion: 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.