Vascular smooth muscle cells (VSMCs), the major cell type in the arterial vessel wall, have a contractile phenotype that maintains the normal vessel structure and function under physiological conditions. In response to stress or vascular injury, contractile VSMCs can switch to a less differentiated state (synthetic phenotype) to acquire the proliferative, migratory, and synthetic capabilities for tissue reparation. Imbalances in VSMCs phenotypic switching can result in a variety of cardiovascular diseases, including atherosclerosis, in-stent restenosis, aortic aneurysms, and vascular calcification. It is very important to identify the molecular mechanisms regulating VSMCs phenotypic switching to prevent and treat cardiovascular diseases with high morbidity and mortality. However, the key molecular mechanisms and signaling pathways participating in VSMCs phenotypic switching have still not been fully elucidated despite long-term efforts by cardiovascular researchers. In this review, we provide an updated summary of the recent studies and systematic knowledge of VSMCs phenotypic switching in atherosclerosis, in-stent restenosis, aortic aneurysms, and vascular calcification, which may help guide future research and provide novel insights into the prevention and treatment of related diseases.

BACKGROUND: In-stent restenosis is characterized by a significant reduction in lumen diameter within the stented segment, primarily attributed to excessive proliferation of vascular smooth muscle cells (VSMCs) and neointimal hyperplasia. PFN1 (profilin-1), an actin-sequestering protein extensively studied in amyotrophic lateral sclerosis, remains less explored in neointimal hyperplasia. METHODS: Utilizing single-cell RNA sequencing alongside data from in-stent restenosis patients and various experimental in-stent restenosis models (swine, rats, and mice), we investigated the role of PFN1 in promoting VSMC phenotype switching and neointimal hyperplasia. RESULTS: Single-cell RNA sequencing of stenotic rat carotid arteries revealed a critical role for PFN1 in neointimal hyperplasia, a finding corroborated in stented swine coronary arteries, in-stent restenosis patients, PFN1 ^SMC-IKO (SMC-specific PFN1 knockout) mice, and PFN1 overexpressed mice. PFN1 deletion was shown to suppress VSMC phenotype switching and neointimal hyperplasia in PFN1 ^SMC-IKO mice subjected to a wire-injured model. To elucidate the observed discordance in PFN1 mRNA and protein levels, we identified that METTL3 (N ⁶ -methyladenosine methyltransferase) and YTHDF3 (YTH N6-methyladenosine RNA binding protein F3; N ⁶ -methyladenosine–specific reader) enhance PFN1 translation efficiency in an N ⁶ -methyladenosine–dependent manner, confirmed through experiments involving METTL3 knockout and YTHDF3 knockout mice. Furthermore, PFN1 was mechanistically found to interact with the phosphorylation of ANXA2 (annexin A2) by recruiting Src (SRC proto-oncogene, nonreceptor tyrosine kinase), promoting the phosphorylation of STAT3 (signal transducer and activator of transcription 3), a typical transcription factor known to induce VSMC phenotype switching. CONCLUSIONS: This study unveils the significance of PFN1 N ⁶ -methyladenosine modification in VSMCs, demonstrating its role in promoting phenotype switching and neointimal hyperplasia through the activation of the p-ANXA2 (phospho-ANXA2)/STAT3 pathway.

BACKGROUND: Vascular smooth muscle cell (VSMC) phenotypic modulation is responsible for the pathogenesis of hyper-muscularized arterial diseases. Recent studies have highlighted the critical role of epigenetic regulation in VSMC fate. However, the mechanisms underlying the precise regulation of the epigenetic machinery in VSMC remain unclear. METHODS: Using mouse aortic smooth muscle cells, carotid artery injury mouse model, and human atherosclerosis data sets, we identified GRK2 (G-protein–coupled receptor kinase 2) as a novel epigenetic regulator governing VSMC fate. RESULTS: GRK2 expression was found to be elevated in dedifferentiated VSMCs. Pharmacological or genetic silencing of GRK2 inhibited VSMC phenotypic switching. Mechanistic investigations demonstrated that GRK2 modulated VSMC phenotype via DNMT1 (DNA methyltransferase 1)-mediated DNA methylation. GRK2 phosphorylated DNMT1, stabilizing it by modulating its ubiquitination. Hypermethylated VSMC exhibited reduced expression of contractile-associated proteins. Inhibition of DNMT1 abolished the effects of GRK2 overexpression on VSMC phenotype, indicating a DNMT1-mediated mechanism. CONCLUSIONS: Our findings revealed that the GRK2-DNMT1 signaling axis is a critical regulator in VSMC phenotypic switching and present a potential therapeutic target for vascular remodeling.

N6-methyladenosine (m6A) is the most common and abundant internal co-transcriptional modification in eukaryotic RNAs. This modification is catalyzed by m6A methyltransferases, known as “writers”, including METTL3/14 and WTAP, and removed by demethylases, or “erasers”, such as FTO and ALKBH5. It is recognized by m6A-binding proteins, or “readers”, such as YTHDF1/2/3, YTHDC1/2, IGF2BP1/2/3, and HNRNPA2B1. Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality worldwide. Recent studies indicate that m6A RNA modification plays a critical role in both the physiological and pathological processes involved in the initiation and progression of CVDs. In this review, we will explore how m6A RNA methylation impacts both the normal and disease states of the cardiovascular system. Our focus will be on recent advancements in understanding the biological functions, molecular mechanisms, and regulatory factors of m6A RNA methylation, along with its downstream target genes in various CVDs, such as atherosclerosis, ischemic diseases, metabolic disorders, and heart failure. We propose that the m6A RNA methylation pathway holds promise as a potential therapeutic target in cardiovascular disease.

Background: The clinical benefit of intravascular imaging (IVI)‐guided drug‐eluting stent implantation in patients with diabetes remains debated. The aim of this study was to compare 1‐year cardiac death between IVI‐guided and angiography‐guided drug‐eluting stent implantation in patients with diabetes. Methods: We analyzed 11 530 patients with diabetes and coronary artery disease who underwent drug‐eluting stent implantation from a prospective multicenter registry, stratified by IVI group (n=2425) and angiography group (n=9105). To minimize confounding, 1:1 propensity score matching was performed, resulting in 2409 matched pairs with balanced baseline clinical and angiographic characteristics. The primary end point was 1‐year cardiac death. Hazard ratios (HRs) with 95% CIs were estimated using Cox proportional hazards models, while Fine‐Gray subdistribution hazard models were used for outcomes with competing risks. Results: After propensity score matching, the IVI group had a greater number of implanted stents, longer total stent length, larger mean stent diameter, and larger post‐dilation balloon diameter (all P <0.05). During 1‐year follow‐up, patients in the IVI group had a significantly lower risk of cardiac death compared with the angiography group (2.5% versus 4.3%; HR 0.59; 95% CI 0.43–0.80; P <0.001), which was confirmed by Fine‐Gray competing risk analysis. Moreover, IVI guidance was associated with the lower risk of 1‐year target lesion revascularization (3.1% versus 4.5%; HR 0.68; 95% CI 0.51–0.91; P =0.011) and definite/probable stent thrombosis (0.9% versus 1.6%; HR 0.56; 95% CI 0.33–0.96; P =0.036) compared with angiography guidance. Conclusions: In patients with diabetes and coronary artery disease, IVI‐guided drug‐eluting stent implantation revealed a significantly lower risk of 1‐year cardiac death than angiography guidance.

N6-methyladenosine (m6A) is the most common and abundant internal co-transcriptional modification in eukaryotic RNAs. This modification is catalyzed by m6A methyltransferases, known as "writers," including METTL3/14 and WTAP, and removed by demethylases, or "erasers," such as FTO and ALKBH5. It is recognized by m6A-binding proteins, or "readers," such as YTHDF1/2/3, YTHDC1/2, IGF2BP1/2/3, and HNRNPA2B1. Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality worldwide. Recent studies indicate that m6A RNA modification plays a critical role in both the physiological and pathological processes involved in the initiation and progression of CVDs. In this review, we will explore how m6A RNA methylation impacts both normal and disease states of the cardiovascular system. Our focus will be on recent advancements in understanding the biological functions, molecular mechanisms, and regulatory factors of m6A RNA methylation, along with its downstream target genes in various CVDs, such as atherosclerosis, ischemic diseases, metabolic disorders, and heart failure. We propose that the m6A RNA methylation pathway holds promise as a potential therapeutic target in cardiovascular disease.