Vascular diseases present a significant threat to human health worldwide. Atherosclerosis is the most prevalent vascular disease, accounting for the majority of morbidity and mortality globally. Vascular calcification is a dynamic pathological process underlying the development of atherosclerotic plaques and involves the phenotypic transformation of vascular smooth muscle cells (VSMCs) into osteogenic cells. Specifically, the phenotypic switch in VSMCs often involves modifications in gene expression due to epigenetic changes, including DNA methylation, histone modification, and non-coding RNAs. Understanding the role of these epigenetic changes in regulating the pathophysiology of vascular calcification, along with the proteins and pathways that mediate these changes, will aid in identifying new therapeutic candidates to enhance vascular health. This review discusses a comprehensive range of epigenetic modifications and their implications for vascular health and the development of vascular calcification.

Vascular aging, aortic stiffness and hypertension are mechanistically interrelated. The perspective presented here will focus mainly on the molecular mechanisms of age-associated increases in the stiffness of the vascular smooth muscle cell (VSMC). This review will highlight the mechanisms by which the VSMC contributes to disorders of vascular aging. Distinct functional sub-components of the vascular cell and the molecular mechanisms of the protein-protein interactions, signaling mechanisms and intracellular trafficking processes in the setting of the aging aorta will be detailed.

Smooth muscle cell (SMC) contraction and vascular tone are modulated by phosphorylation and multiple modifications of the thick filament, and thin filament regulation of SMC contraction has been reported to involve extracellular regulated kinase (ERK). Previous studies in ferrets suggest that the actin‐binding protein, calponin 1 (CNN1), acts as a scaffold linking protein kinase C (PKC), Raf, MEK and ERK, promoting PKC‐dependent ERK activation. To gain further insight into this function of CNN1 in ERK activation and the regulation of SMC contractility in mice, we generated a novel Calponin 1 knockout mouse (Cnn1 KO) by a single base substitution in an intronic CArG box that preferentially abolishes expression of CNN1 in vascular SMCs. Using this new Cnn1 KO mouse, we show that ablation of CNN1 has two effects, depending on the cytosolic free calcium level: (1) in the presence of elevated intracellular calcium caused by agonist stimulation, Cnn1 KO mice display a reduced amplitude of stress and stiffness but an increase in agonist‐induced ERK activation; and (2) during intracellular calcium depletion, in the presence of an agonist, Cnn1 KO mice exhibit increased duration of SM tone maintenance. Together, these results suggest that CNN1 plays an important and complex modulatory role in SMC contractile tone amplitude and maintenance.

BACKGROUND: Vascular calcification is an active process driven by osteogenic phenotypic transition of vascular smooth muscle cells (VSMCs) and regulated by a bone-related gene regulatory network. Recent studies showed that FAK (focal adhesion kinase) regulates bone formation by affecting the cellular localization of HDAC (histone deacetylase) 4 and HDAC5. However, it is not known whether FAK exerts effects on vascular calcification in VSMCs through regulating HDACs. METHODS: We used perturbational assays to assess the role of HDAC4, HDAC5, and FAK in VSMC calcification. Pharmacological inhibition and gene silencing of FAK were used to evaluate effects on calcification, cell migration, and the expression of procalcification factors. Leptomycin was used to inhibit the nuclear export of HDACs. In addition, ex vivo cultures of mouse and human arteries were treated with a FAK inhibitor to assess effects on arterial calcification. Single-cell transcriptomic expression of FAK was examined in healthy and diseased human coronary arteries. RESULTS: HDAC4 and HDAC5 were identified as positive regulators of vascular calcification. Pharmacological inhibition or gene silencing of FAK blocked VSMC calcification, abrogated the osteogenic medium–induced elevation of procalcification factors, and reduced cell migration. FAK inhibition reduced HDAC4 and HDAC5 phosphorylation and enhanced nuclear localization of these HDAC proteins. Inhibition of HDAC4 and HDAC5 nuclear export with leptomycin showed similar effects on calcification as FAK inhibition. Treatment with the FAK inhibitor attenuated the calcification of ex vivo mouse and human arteries. FAK gene expression was dysregulated in human diseased coronary arteries compared with healthy coronary arteries, and, in single-cell analysis of human arterial tissue, FAK expression was highest in VSMCs at an intermediate state between contractile and osteogenic phenotypes. CONCLUSIONS: FAK promotes VSMC calcification, at least in part, via phosphorylation of HDAC4 and HDAC5. Targeted regulation of the activity of FAK, HDAC4, and HDAC5 may be an effective strategy for the treatment of vascular calcification.

Vascular calcification represents a convergent pathological feature of diverse cardiovascular diseases, yet the upstream molecular programs orchestrating this process remain poorly defined. Here, we uncover fibronectin type III domain-containing 1 (FNDC1) as a previously unrecognized regulator of vascular calcification across both microvascular and macrovascular beds. Integrative transcriptomic profiling of human calciphylaxis lesions and atherosclerotic coronaries identified FNDC1 as one of the most significantly upregulated genes. In primary human vascular smooth muscle cells, FNDC1 drove osteogenic phenotype switch and vascular calcification through activation of PI3K/AKT signaling and metabolic reprogramming. Mechanistically, FNDC1 directly binds to nicotinamide phosphoribosyltransferase (NAMPT) resulting in elevated intracellular NAD⁺ levels, thus coupling vascular signaling to control of NAD⁺ biosynthesis. In murine models, genetic deletion of Fndc1 or pharmacologic inhibition of NAMPT suppressed arterial calcification and prolonged survival. Clinically, circulating FNDC1 levels were elevated in patients with both calciphylaxis and coronary artery disease and independently predicted cardiovascular risk in 42,687 UK Biobank participants. Together, these findings establish FNDC1 as a central mediator of vascular pathology and highlight the FNDC1– NAMPT-NAD ⁺ axis as a promising target for therapeutic intervention.