Regulation of Vascular Calcification by M1-Type Macrophage-Derived Semaphorin 4D

Vascular calcification is a critical pathological hallmark of cardiovascular diseases. Although previous studies have indicated that M1 macrophages significantly promote calcification, the exact underlying mechanisms remain unclear. This study examined whether semaphorin 4D (Sema4D), a class IV semaphorin involved in atherosclerosis development, is secreted by M1 macrophages and contributes to the calcification of vascular smooth muscle cells (VSMCs). We observed elevated expression and secretion of Sema4D in both M1 and M2 macrophages, with significantly higher levels in M1-polarized cells. M1 macrophages promoted VSMC calcification in both co-culture and conditioned medium systems, as evidenced by increased alkaline phosphatase activity, enhanced calcium deposition, and upregulation of osteogenic markers. Notably, neutralization of Sema4D in M1 conditioned medium using pepinemab, an anti-Sema4D antibody, effectively attenuated VSMC calcification induced by M1 macrophages. Conversely, supplementation of conditioned medium with recombinant Sema4D enhanced calcification and osteogenic signaling in VSMCs, further supporting the pro-calcifying role of Sema4D. Collectively, these findings highlight macrophage-derived Sema4D as a pivotal regulator of vascular calcification and a promising therapeutic target.