Deficient NAT10-mediated ac4C modification destabilizes SCRIB mRNA and impairs endometrial decidualization in recurrent spontaneous abortion.

Defective decidualization of human endometrial stromal cells (HESCs) is an important pathological feature of recurrent spontaneous abortion (RSA). Although chemical modifications regulate the stability and functional fate of RNA macromolecules, the role of N4-acetylcytidine (ac4C) modification in controlling specific messenger RNAs during decidualization remains poorly understood. Here, we identified N-acetyltransferase 10 (NAT10), an RNA acetyltransferase responsible for ac4C modification, as a critical regulator of decidualization. NAT10 was significantly downregulated in decidual stromal cells from patients with RSA, and both genetic depletion and pharmacological inhibition of NAT10 impaired decidualization in HESCs. Integrated RNA sequencing, ac4C RNA immunoprecipitation sequencing, and quantitative proteomic analyses identified SCRIB mRNA as a key downstream RNA macromolecule regulated by NAT10-dependent ac4C modification. NAT10 enhanced the ac4C enrichment and stability of SCRIB mRNA, thereby maintaining SCRIB expression during decidualization. Conversely, NAT10 depletion reduced SCRIB mRNA stability and disrupted decidualization-associated cellular function. Rescue experiments further demonstrated that wild-type NAT10, but not the catalytically inactive mutants G641E or K290A, restored SCRIB expression and decidualization in NAT10-deficient HESCs, supporting a requirement for the RNA acetyltransferase activity of NAT10. Restoration of SCRIB expression rescued the decidualization defects caused by NAT10 depletion. Collectively, these findings define a NAT10-ac4C-SCRIB regulatory axis in which ac4C modification determines the stability and functional fate of SCRIB mRNA and provide a macromolecular mechanism underlying defective decidualization in RSA.