6544 M6A methylation of PLCβ in the hypothalamus regulates GnRH synthesis and secretion by interfering Ca2+ signaling pathway

Abstract Disclosure: X. Yin: None. S. Zang: None. P. Li: None. Backgrounds: In recent years, the incidence of precocious puberty has increased rapidly, posing a serious threat to girls' physical and mental health. Epigenetic changes, especially m6A methylation modification, may be an important influencing factor. Researches had found that m6A modification plays an irreplaceable role in the development and functional homeostasis of the nervous system. A variety of factors could changed RNA m6A level in the hypothalamus and affect the process of adolescent sexual development. In the study,we aimed to explore the specific role of m6A methylation in precocious puberty, and to identify its downstream target genes by multi-omics approach and to verify its function. Hypothesis The demethylase FTO regulated the m6A modification of the target gene in the hypothalamus to affect the synthesis and secretion of GnRH and regulate the initiation of puberty. Methods: The modification abundance of m6A was investigated by the girls with central precious puberty (CPP). The changes of m6A modification in total RNA and the expression of important modulator genes were detected by colorimetry and qRT-PCR respectively in the hypothalamic ARC nucleus of female rats at three different developmental stages (juvenile, early puberty and puberty) and precocious rat model. MeRIP and mRNA sequencing was used to screen target genes which related to puberty development. Knockdown or overexpression of FTO were constructed using plasmid or lentivirus transfection. The target mRNA targeted regulated by FTO was verified with RNA-seq, qRT-PCR, WB and Flow cytometry. Results This study confirmed that the level of RNA m6A in the peripheral blood of the precocious group was significantly higher than that of the control group. The level of RNA m6A in the hypothalamus of female rats gradually increases with the development of puberty, and the expression of demethylase gradually decreases. MeRIP-seq combined with mrNA-seq screening analysis showed that the m6A modification of PLCβ in the ARC nucleus of the hypothalamus was reduced, and its mRNA expression was significantly increased in sexually precocious female rats. Combined with bioinformatics analysis, it was found that there were multiple m6A modified motif sites on the mRNA of PLCβ, and luciferase experiment confirmed that there was a regulatory relationship between them. After over-expressing FTO, the mRNA and protein expression of PLCβ were significantly increased, and the up-regulation of FTO expression induced a significant increase in intracellular Ca2+ concentration, the expression of CAM, and the activation of Ca2+ signaling pathway. Conclusions In the ARC nucleus of the hypothalamus, FTO affects the synthesis and secretion of GnRH by regulating the m6A modification level of PLCβ through the Ca2+ signaling pathway, and interferes with the initiation of female sexual development. Presentation: 6/1/2024