Diabetes is not only a major independent risk factor for atherosclerosis (Geng, 2023) but is also associated with increased occurrences of acute cardiovascular events, such as acute coronary syndrome, acute myocardial infarction, and stroke (Nissen and Wolski, 2007; Dormandy et al., 2005; He et al., 2022; Han et al., 2023). Patients with diabetes who present with unstable angina or non-ST-elevation myocardial infarction have a 1-year mortality rate nearly equal to that of patients without diabetes who present with ST-elevation myocardial infarction (Donahoe et al., 2007). Additionally, research indicates that patients with diabetes experience a 3-fold increase in age-adjusted cardiovascular mortality (Sanon et al., 2012; Zhu et al., 2021). These findings support the well-established view that diabetes is a risk equivalent for coronary atherosclerotic disease.

Although the mechanisms behind the progression of atherosclerosis related to diabetes mellitus are not fully understood, there is an acknowledged increase in disease burden and higher levels of vascular calcification in these patients at both clinical and pathological levels (Guo et al., 2021). Calcification, the presence of calcium deposits in the vessel wall, is a feature of advanced atherosclerosis and decreases the vessel wall's elasticity and compliance (Yu and Li, 2020). Studies reveal that osteoblastic differentiation of VSMCs plays an essential role in the development of atherosclerotic calcification (Li et al., 2020; Dai et al., 2022). Numerous pathogenic factors, including oxidative stress, high glucose (HG), and inflammation, are implicated in atherosclerotic calcification (Tian et al., 2018; Canet-Soulas et al., 2021). Nonetheless, the underlying mechanisms driving this process remain inadequately characterized.

Nitrosative stress has been associated with the regulation of signal transduction, gene expression, cellular growth, and apoptosis (Chamorro et al., 2016). Recent reports indicate that nitrosative stress contributes to heart failure with preserved ejection fraction (Schiattarella et al., 2019). Protein S-nitrosylation mediated by nitric oxide (NO) plays a key role in nitrate tolerance and cardiac diastolic dysfunction (Zhou et al., 2019; Yoon et al., 2021). Our research shows that nitrosative stress disrupts coronary collateral circulation during metabolic disorders through protein S-nitrosylation (Bai et al., 2024).

AMP-activated protein kinase (AMPK) is a heterodimer composed of an α-catalytic subunit and β/γ-regulatory subunits. In general, AMPKα T172 phosphorylation reflects AMPK kinase activity. Essentially, the function of AMPK is determined by AMPKβ and AMPKγ. The β subunit acts as a connector between the α and γ subunits, thereby determining the spatial conformation of the AMPKα/β/γ complex (Smiles et al., 2024). AMPKγ senses intracellular AMP levels and allosterically activates AMPK (Li et al., 2015). It has been demonstrated that AMPK dysfunction induces VSMCs dysfunction and phenotypic switching (Wang et al., 2012; Liang et al., 2018; Ding et al., 2016; Lee et al., 2016). The AMPKβ1 subunit is widely expressed in vascular smooth muscle cells and is crucial for glucose homeostasis, providing protection against hyperglycemia (Igata et al., 2005; Neopane et al., 2022).

Given the critical roles of VSMCs in cardiovascular diseases, the biological features of AMPKβ1, and the pathophysiological mechanisms underlying atherosclerotic calcification, we hypothesize that nitrosative stress is involved in diabetic atherosclerotic calcification through VSMC phenotypic switching. Our studies showed that HG upregulates inducible nitric oxide synthase (iNOS), thereby inducing nitrosative stress and subsequent S-nitrosylation of AMPKβ1, which promotes VSMC phenotypic switching. In atherosclerotic mice with diabetes, mutations at Cys173 and Cys223 of AMPKβ1 reduced atherosclerotic calcification.