m6A contributes to a pro-survival state in GC-2 cells by facilitating DNA damage repair: Novel perspectives on the mechanism underlying DEHP genotoxicity in male germ cells

Abstract

Di(2-ethyl-hexyl) phthalate (DEHP), an environmental endocrine disruptor, can destroy the sperm genomic integrity and impairs spermatogenesis. N6-methyladenosine (m6A) is involved in the cellular effects of DEHP. However, the genotoxic effect of DEHP on spermatocytes and the possible role of m6A in this process remain unclear. This study demonstrated that m6A alleviates DEHP genotoxicity in GC-2 cells. In DEHP-treated mice, DNA double-strand breaks (DSBs) were induced in the testis and spermatocytes. To further explore the molecular mechanism of DEHP genotoxicity on spermatocytes, GC-2 cells were exposed to DEHP. DEHP produced distinct genotoxicity and caused DSBs, which led to the inhibition of DNA synthesis and cell cycle arrest. The DNA damage response (DDR) was initiated to repair the DSBs induced by environmentally relevant levels of DEHP (100 μM and 200 μM). During this process, METTL3 upregulated m6A, which facilitated the DDR via stabilizing the DNA damage repair factors (Rad51 and Xrcc5) mRNA to maintain the pro-survival state. Moreover, Mettl3 knockdown partially inhibited DDR. Interestingly, high-dose DEHP (400 μM and 600 μM) directly induced apoptosis rather than the pro-survival state. Altogether: METTL3-mediated m6A participates in maintaining the pro-survival state by upregulating DDR, providing guidance for mitigating the genotoxicity of environment-related level DEHP exposure.

Keywords: DEHP; DNA damage repair; Genotoxicity; Male germ cells; m6A.