Ddah1 deficiency promotes ADMA accumulation to exacerbate polycystic ovary syndrome by enhancing androgen receptor expression

Dimethylarginine dimethylaminohydrolase 1 (DDAH1) is an important regulator of plasma asymmetric dimethylarginine (ADMA) levels, which are positively correlated with hyperandrogenemia in polycystic ovary syndrome (PCOS) patients. To elucidate the role of DDAH1 in the pathogenesis of PCOS, we used Ddah1 knockout heterozygous ( Ddah 1 +/− ) mice to investigate ADMA/DDAH1 pathways on dehydroepiandrosterone (DHEA)–induced ovarian dysfunction. After DHEA treatment for 3 weeks, Ddah1 +/− mice developed more severe ovarian dysfunction, including higher testosterone levels and an increased number of cystic follicles. Compared to the DHEA treated WT mice, Ddah1 +/− mice exhibited higher serum ADMA levels. In the ovaries of DHEA–treated mice, deficiency of Ddah1 resulted in higher levels of oxidative stress, greater expressions of testosterone synthesis enzyme–CYP11A1, CYP17A1 and androgen receptor (AR). In KGN or HEK293 cells, ADMA treatment induced the expression of CYP11A1 and AR. Conversely, DDAH1 overexpression attenuated AR expression. GW4064 treatment in PCOS rats reduced serum ADMA, serum testosterone, and ovarian AR expression. Furthermore, direct data independent acquisition (directDIA)–based proteomics revealed that DDAH1 may affect multiple metabolic pathways by altering protein expression in the cytoplasm, nucleus and mitochondria. In summary, our results are consistent with the possibility that the ADMA/DDAH1 axis is involved in ovarian functions such as testosterone synthesis and AR signaling in PCOS. Interventions aimed at modulating DDAH1 activity or ADMA levels could be considered as one of several directions for future PCOS research, though further validation is needed.