Abstract Background Vascular calcification is a major risk factor for cardiovascular disease (CVD), driven by the osteogenic transformation of vascular smooth muscle cells (VSMCs). Lipoprotein(a) Lp(a) is a known cardiovascular risk factor, yet its role and potential regulatory mechanisms in vascular calcification have not been well-established. METTL14, a key m6A methyltransferase and epigenetic regulator, is located within the VSMC calcification susceptibility region. Purpose This study investigates the role of Lp(a) in vascular calcification and its potential regulatory effect on METTL14. Methods Human aortic smooth muscle cells (HASMCs) were treated with 20 μg/mL Lp(a) protein or phosphate-buffered saline (PBS) as a control, and cultured in a high inorganic phosphate (Pi) solution for 14 days to establish an in vitro model, with calcification assessed by Alizarin Red staining. The effect of Lp(a) on METTL14 expression was examined at mRNA and protein levels. Functional studies with METTL14 overexpression and knockdown evaluated its role in Lp(a)-induced calcification. RNA-sequencing analysis and rescue experiments were performed to identify downstream target genes. Results Lp(a) treatment significantly increased calcific deposition in HASMCs. It upregulated METTL14 protein expression without affecting METTL14 mRNA levels. Overexpression of METTL14 enhanced HASMC calcification under high Pi conditions, whereas METTL14 knockdown reduced Lp(a)-induced calcification. RNA-seq analysis identified nephroblastoma overexpressed (NOV/CCN3) gene as a downstream target of METTL14, which was validated by qPCR and Western blot analyses. Functional rescue experiments confirmed that the calcification-promoting effect of METTL14 was mediated through CCN3. Conclusion Lp(a) promotes HASMC calcification under high Pi conditions by upregulating METTL14 protein expression. METTL14, in turn, enhances HASMC calcification by positively regulating CCN3 gene expression. These findings reveal a novel Lp(a)-METTL14-CCN3 regulatory axis in VSMC calcification, warranting further in vivo studies to validate its role and therapeutic potential in vascular calcification.Si-METTL14 Inhibited Lp(a)-Calcification Ad-METTL14 combined with Si-CCN3
Li et al. (Sat,) studied this question.