Disorder of Methionine Metabolism Triggers Vascular Calcification via DNMT3A in CKD

Background: Vascular calcification is closely related to the occurrence and mortality of cardiovascular disease (CVD) in CKD patients, and the specific mechanism of its pathogenesis is not yet clear. Previous studies have found that elevated levels of methionine metabolites are risk factors for developing cardiovascular disease (CVD), but the mechanism remains unclear. This study aims to explore the role of methionine metabolism in vascular calcification in CKD. Methods: Liquid chromatography-mass spectrometry was used to detect the levels of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in the plasma of CKD patients; 5/6 nephrectomy combined with high phosphorus diet and high phosphorus medium was used to establish in vivo and in vitro CKD vascular calcification models. Methylation-specific polymerase chain reaction (MSP) was used to detect whether the target gene has undergone methylation. Results: The plasma levels of SAM, SAH, and SAM/SAH ratios in the CKD patient group were significantly increased. Also, CKD patients had significantly increased levels of 5-mC and DNMT3A expression in calcified arteries IHC staining. The proportion of 5-mC modification in the total DNA of blood vessels in CKD mice significantly increased;5Aza alleviated vascular calcification in vivo; Idownregulating the expression of DNMT3A can alleviate VC. Further validation experiments found that under high phosphorus stimulation, the intracellular arginine content of VSMC decreased, and the expression of arginine synthase ASS1 and ASL decreased. Knocking down DNMT3A can reverse the decrease in intracellular arginine content of VSMC caused by high phosphorus stimulation and simultaneously reverse the expression levels of key arginine synthase ASS1 and ASL; MSP detection showed that knocking down DNMT3A can reduce the high methylation levels of ASS1 and ASL under high phosphorus stimulation. Conclusion: Disordered methionine metabolism in CKD patients with vascular calcification mediates hypermethylation of vascular tissue, accompanied by increased expression of DNMT3A. Inhibiting the expression of DNMT3A can alleviate CKD-related vascular calcification. DNMT3A silences the expression of arginine synthase ASS1 and ASL through DNA hypermethylation, inhibits arginine synthesis, and accelerates the occurrence of vascular calcification. Funding: Government Support – Non-U.S.