Abstract Body: Background: Diabetes mellitus is strongly associated with an increased incidence of vascular calcification. Under hyperglycemic conditions, vascular smooth muscle cells (VSMC) undergo a phenotypic switch from a contractile to an osteogenic state, resulting in mineral deposition within the arterial media. However, the molecular mechanisms driving this diabetic VSMC fate transition remain incompletely understood. The polybromo-associated BAF (PBAF) chromatin-remodeling complex plays a critical role in cell fate regulation. Plant Homeodomain Finger Protein 10 (PHF10), a PBAF subunit, is markedly repressed under diabetic conditions, yet the mechanisms underlying this repression and its role in maintaining the contractile VSMC phenotype remain unclear.
Methods: The public RNA-seq dataset GSE66280 was analyzed to assess changes in osteogenic markers and PBAF subunits in VSMC under diabetic versus control conditions. Primary mouse VSMC were cultured under high- or normal-glucose conditions, followed by Western blotting and qPCR analyses of PBAF subunits, contractile and osteogenic markers. VSMC-specific PHF10 knockout mice were generated by crossing floxed PHF10 mice with SM22α-Cre mice. Gain-of-function studies were performed using lentiviral-mediated PHF10 overexpression. Alizarin Red staining was used to assess calcium deposition in vitro and in mouse aortic rings ex vivo.
Results: Analysis of dataset GSE66280 identified PHF10 as one of the most significantly repressed PBAF subunits under diabetic conditions. PHF10-deficient VSMC exhibited increased Runt-related transcription factor 2 expression at both transcriptional and protein levels, accompanied by enhanced calcification and elevated calcium content in vitro (n=5 biological repeats). Consistently, at ex vivo, aortic rings from PHF10 knockout mice were more susceptible to vascular calcification than those from control littermates (n=3). In contrast, PHF10 overexpression suppressed Runx2 expression, reduced calcification, and lowered calcium deposition (n=5 biological repeats).
Conclusions: These findings identify PHF10 as a protective regulator of vascular calcification by maintaining the contractile phenotype of VSMCs. Repression of PHF10 under diabetic conditions promotes osteogenic transition and calcification, whereas restoration of PHF10 expression mitigates these effects. PHF10 therefore represents a potential therapeutic target for preventing diabetes-associated vascular calcification.