Inhibition of enzymes involved in collagen cross-linking reduces vascular smooth muscle cell calcification

Vascular smooth muscle cells (VSMCs) transdifferentiate into osteoblast-like cells during vascular calcification, inducing active remodeling and calcification of the extracellular matrix (ECM). Intracellular and extracellular enzymes, such as lysyl hydroxylase 1 (PLOD1) and lysyl oxidase (LOX), contribute to ECM maturation and stabilization. We assessed the contribution of these enzymes to hyperphosphatemia-induced calcification. Human and murine VSMCs were differentiated into functional osteoblast-like cells by high-phosphate medium (HPM) conditioning. HPM promoted ECM calcification and up-regulated osteoblast markers associated with induction of LOX and PLOD1 expression and with an increase in ECM-insoluble collagen deposition. Murine VSMCs from transgenic mice overexpressing LOX (TgLOX) exhibited an increase in HPM-dependent calcification and osteoblast commitment compared with wild-type cells. Similarly, enhanced HPM-induced calcification was detected in aorta from TgLOX. Conversely, β-aminopropionitr...