MiR-204 regulates autophagy and cell viability by targeting BDNF and inhibiting the NTRK2-dependent PI3K/Akt/mTOR pathway in a human granulosa cell line exposed to bisphenol A

Bisphenol A (BPA) is a widespread endocrine disruptor that mimics estrogen. The accumulation of BPA within the human body has been shown to be detrimental to ovarian function. However, few studies have focused on the specific mechanisms by which it causes harm to granulosa cells (GCs), pivotal ovarian cells that are responsible for the growth and function of oocytes. In vitro research was conducted using human GC lines (KGN cells). The cells were exposed to various concentrations of BPA (0.1, 1, 10, or 100 µM) for either 24 or 48 hours. Here, our findings indicate that 100 μM BPA inhibits KGN cell proliferation and promotes cell autophagy through inhibiting the PI3K/Akt/mTOR pathway. Interestingly, these effects could be partly reversed by an NTRK2 activator (LM22b-10). NTRK2 is the receptor for BDNF. Moreover, via the use of bioinformatics tools, miR-204 was predicted to target BDNF. Additionally, our findings confirmed that miR-204 has the ability to directly target BDNF through a luciferase assay. Downregulation of miR-204 abrogated the BPA exposure-mediated effects on proliferation and autophagy. Furthermore, the inhibition of miR-204 significantly reversed the downregulation of PI3K/Akt/mTOR pathway-related molecules. Similarly, we validated miR-204 as a novel miRNA involved in BPA-mediated damage to GC proliferation and autophagy, and our data provide the first in vitro evidence that increasing miR-204 expression and inhibiting the BDNF/NTRK2-mediated PI3K/Akt/mTOR signaling pathway are involved in the BPA-induced toxic effects in KGN cells.