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.

Automated summary

Celastrol was found to effectively improve type 2 diabetes through targeting the ChREBP-TXNIP axis. It directly bound to ChREBP, inhibiting its nuclear translocation and promoting proteasomal degradation, leading to the repression of TXNIP transcription and ultimately ameliorating T2DM.