Melatonin inhibits circadian gene DEC1 and TLR2/MyD88/NF-κB signaling pathway to alleviate renal injury in type 2 diabetic mice.

Background: Diabetic Kidney Disease (DKD) is a complex disease associated with circadian rhythm and biological clock regulation disorders. Melatonin (MT) is considered a hormone with renal protective effects, but its mechanism of action in DKD is unclear.

Methods: We used the GSE151325 dataset from the GEO database for differential gene analysis and further explored related genes and pathways through GO and KEGG analysis and PPI network analysis. Additionally, this study used a type 2 diabetes db/db mouse model and investigated the role of melatonin in DKD and its relationship with clock genes through immunohistochemistry, Western blot, real-time PCR, ELISA, chromatin immunoprecipitation (ChIP), dual-luciferase reporter technology, and liposome transfection technology to study DEC1 siRNA.

Results: Bioinformatics analysis revealed the central position of clock genes such as CLOCK, DEC1, Bhlhe41, CRY1, and RORB in DKD. Their interaction with key inflammatory regulators may reveal melatonin's potential mechanism in treating diabetic kidney disease. Further experimental results showed that melatonin significantly improved the renal pathological changes in db/db mice, reduced body weight and blood sugar, regulated clock genes in renal tissue, and downregulated the TLR2/MyD88/NF-κB signaling pathway. We found that the transcription factor DEC1 can bind to the TLR2 promoter and activate its transcription, while CLOCK's effect is unclear. Liposome transfection experiments further confirmed the effect of DEC1 on the TLR2/MyD88/NF-κB signaling pathway.

Conclusion: Melatonin shows significant renal protective effects by regulating clock genes and downregulating the TLR2/MyD88/NF-κB signaling pathway. The transcription factor DEC1 may become a key regulatory factor for renal inflammation and fibrosis by activating TLR2 promoter transcription. These findings provide new perspectives and directions for the potential application of melatonin in DKD treatment.