ESPE Abstracts

Background: The etiology of central precocious puberty (CPP) still remains unknown. The abnormal expression of Fat mass and obesity-associated (FTO)-mediated N6-methyladenosine (m6A) has been confirmed to play the crucial roles in CPP. This study aimed to explore the mechanism of FTO-mediated m6A modification of brain-derived neurotrophic factor (BDNF) on CPP with puberty onset.

Methods: The qRT-PCR and immunofluorescence were carried out to confirm the expression and location of BDNF at different development stages in female rats. The levels of BDNF in peripheral serum was detected by ELISA. Methylated RNA immunoprecipitation sequence (MeRIP-seq), Dual luciferase reporter and RNA stability assays confirmed the interaction between BDNF and FTO. FTO-mediated m6A modification of BDNF on PI3K/AKT pathway were detected by Western blotting.

Results: In female rats, the level of BDNF in hypothalamus increased gradually with puberty. BDNF and GnRH were colocalized in the hypothalamic arcuate nucleus (ARC). Peripheral serum BDNF increased abnormally in girls with CPP. Overexpressing or knockdown BDNF in GT1-7 cells showed that BDNF positively regulate the expression of GnRH. MeRIP-seq analysis showed that m6A methylation of BDNF decreased significantly in pubertal female rats’ hypothalamus. Dual luciferase reporter gene test confirmed that FTO could regulated m6A demethylation of BDNF and promoted BDNF expression. And FTO could enhance the stability of BDNF by the m6A modification. Up-regulating FTO expression could activate the BDNF/PI3K/AKT signaling pathway in GT1-7 cells and female rats’ hypothalamus.

Conclusion: This study revealed that FTO-mediated m6A modification of BDNF could enhance GnRH expression and accelerates puberty onset by activating PI3K/AKT pathway.