METTL3 promotes PGC-1α transcription and alleviates mitochrondrial dysfunction of diabetic nephropathy by targeting lncRNA TUG1 m6A modification

Background: m6A modification plays an important role in various biological processes and can regulate the function of non-coding RNA. Our research group found the m6A level of lncRNA TUG1 was reduced in HK-2 cells cultured with high glucose. Here we study the impact of the important component of m6A-METTL3 on TUG1 in diabetic nephropathy. Objective: Explore the m6A modification mechanism of lncRNA TUG1 and whether METTL3 can promote PGC-1α transcription, alleviate mitochrondrial dysfunction and diabetic renal injury. Methods: Test the m6A modification level of the total RNA and lncRNA TUG1 in HK-2 cells and db/db mice.Detect whether lncRNA TUG1 can combine METTL3 and IGF2BP2 by RIP-PCR. Test the mitochondrial function HK-2 cells and db/db mice. Use transmission electron microscope to observe the morphology of mitochondria in HK-2 cells and db/db mice. Results: RIP-PCR showed that lncRNA TUG1 could bind to METTL3, and IGF2BP2 could recognize the m6A-modified lncRNA TUG1. IGF2BP2 improved the stability of lncRNA TUG1. High glucose and transfection of siTUG1 in HK-2 cells inhibited PGC-1α pathway, and aggravated mitochondrial dysfunction and morphological damages, while overexpression of METTL3 in HK-2 cells and injection of AAV-METTL3 in db/db mice partially rescued the negative effect. Conclusion: RNA m6A methylation/demethylation imbalance may be mainly regulated by METTL3 in HK-2 cells, and involved in the occurrence and development of diabetic nephropathy. METTL3 can promote the expression of TUG1 through m6A modification in a IGF2BP2-dependent manner in HK-2 cells, and regulate the PGC-1α pathway to alleviate mitochrondrial dysfunction of diabetic nephropat