METTL3 regulates glucose transporter expression in placenta exposed to hyperglycemia through the mTOR signaling pathway

Demethylase FTO-mediated m6A modification of SIK1 modulates placental cytotrophoblast syncytialization in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) represents a common complication during pregnancy that affects fetoplacental development. We demonstrated the existence of impaired trophoblast syncytialization under hyperglycemic conditions. However, the exact mechanism remains unknown. RNA N6-methyladenosine (m6A) is an emerging regulatory mechanism of mRNA and participates in various biological processes. We described the global m6A modification pattern in T2DM placenta by the combined analysis of methylated RNA immunoprecipitation sequencing (MeRIP-Seq) and RNA sequencing (RNA-Seq). Both the m6A modification and expression of SIK1, which is critical for syncytialization, were significantly decreased in trophoblast exposed to hyperglycemic conditions. In addition, the m6A demethylase fat mass and obesity-associated protein (FTO) affects the expression and mRNA stability of SIK1 by binding to its 3'-untranslated region (UTR) m6A site. This work reveals that the FTO-m6A-SIK1 axis plays critical roles in regulating syncytialization in the placenta.

Methyltransferase-like 3 modifications of RNAs: Implications for the pathology in the endocrine system

Methyltransferase-like 3 (METTL3) is the most well-known element of N6-methyladenosine modification on RNAs. METTL3 deposits a methyl group onto target RNAs to modify their expression, ultimately regulating various physiological and pathological events. Numerous studies have suggested the significant role of METTL3 in endocrine dysfunction and related disorders. However, reviews that summarize and interpret these studies are lacking. In this review, we systematically analyze such studies, including obesity, type 2 diabetes mellitus (T2DM), T2DM-induced diseases, pancreatic cancer, and thyroid carcinoma. This review indicates that METTL3 contributes remarkably to the endocrine dysfunction and progression of obesity, T2DM, T2DM-induced diseases, pancreatic cancer, and thyroid carcinoma. In conclusion, this review provides a comprehensive interpretation of the mechanism via which METTL3 functions on RNAs and regulates various endocrine dysfunction events and suggest potential associated correlations. Our review, thus, provides a valuable reference for further fundamental studies and clinical applications.