NAT10 governs uterine function and fertility by stabilizing progesterone receptor mRNA via ac4C modification

The N4-acetylcytidine (ac4C) modification is one of the most abundant chemical modifications in mammalian transcriptome, which plays a crucial role in regulating gene expression across various biological processes. In this study, we investigate the role of N4-acetyltransferase 10 (NAT10), the sole enzyme responsible for catalyzing the ac4C modification, in uterine function. Our findings revealed that knockdown of NAT10 in cultured human endometrial stromal cells leads to decreased progesterone receptor (PGR) expression and compromised decidualization. Mechanistically, NAT10 is found to enhance the stability of PGR mRNA through its ac4C modification in the coding sequence (CDS). Furthermore, conditional deletion of Nat10 in the mouse uterus using Pgr-Cre resulted in defective pubertal uterine development, characterized by a thinner stroma and reduced endometrial gland number. These mice were infertile in adulthood, experiencing failures in both implantation and decidualization. However, heterozygous Nat10 conditional knockout mice showed reduced NAT10 expression in the uterus without affecting uterine development or fertility. To bridge the gap between heterozygous and homozygous knockout conditions, we employed Remodelin, an inhibitor of NAT10, in adult female mice, to mimic an intermediate gene dosage. Our results demonstrated that inhibiting NAT10 with Remodelin preserved uterine structures but disrupted the PGR signaling pathway, leading to impaired uterine function during pregnancy. In conclusion, our study provides compelling evidence that NAT10 safeguards uterine function and fertility by regulating the ac4C modification of PGR mRNA. SignificanceHere we identified NAT10-catalyzed ac4C modification of progesterone receptor (PGR) mRNA as a crucial mechanism regulating PGR expression by enhancing its mRNA stability. In vitro studies using human endometrial stromal cells show that the NAT10-PGR axis is required for decidualization. Additionally, genetic and pharmacologic manipulations in mice further demonstrate the necessity of NAT10-dependent P4/PGR signaling for uterine function during implantation and decidualization. Our findings highlight the importance of NAT10-mediated ac4C modification in maintaining PGR expression and uterine function.