Abstract Body: Background: The phenotypic switching of vascular smooth muscle cells (VSMCs) plays a crucial role in human occlusive vascular diseases. The VSMC phenotype is regulated by specific cis-regulatory elements and their associated transcription factors (TFs). However, significant gaps remain in our understanding of the specific factors and mechanisms underlying the control of VSMC phenotype.
Methods and results: To identify novel TFs involved in regulating the VSMC phenotype, publicly available single-cell epigenomic and transcriptomic datasets from human and mouse atherosclerotic arteries were reanalyzed. This analysis identified TEAD as a potential key regulator of the VSMC phenotype linked to cardiovascular diseases. Among the four TEAD family TFs, TEAD1 and TEAD3 are highly expressed in VSMCs, with TEAD3 being exclusive to VSMCs and showing reduced expression in phenotypically modulated VSMCs. We further validated the VSMC-restricted expression of TEAD3 using a novel Tead3 knock-in lacZ reporter mouse model. To investigate the roles of TEAD1 and TEAD3, we generated VSMC-specific Tead1/3 single- or double-knockout (dKO) mice by crossing with VSMC-specific Itga8-CreERT2 mice. Three months post-deletion, Tead1/3 dKO mice exhibited artery elongation, aortic wall thickening, vascular remodeling, spontaneous neointima formation, and unexpected severe coronary artery vasculopathy with impaired arterial contractility. In contrast, mice with single deletions of either Tead1 or Tead3 displayed no overt phenotype. Bulk RNA sequencing of Tead1/3-deficient aortas revealed a loss of contractile gene expression and increased expression of pro-inflammatory genes, indicating phenotypic modulation in vivo. Single-cell multi-omics analysis, combining snRNA-seq and snATAC-seq, further demonstrated downregulation of VSMC-specific genes in VSMCs. This was associated with decreased TEAD transcription factor binding activity at promoters and enhancers of these genes in the aortas of Tead1/3 dKO mice.
Conclusions: These findings reveal an undocumented role of TEAD TFs and functional redundancy between TEAD1 and TEAD3 in maintaining the contractile phenotype of VSMCs and vascular homeostasis, through the direct control of a subset of smooth muscle cell-specific contractile genes. The identification of TEADs as essential regulators of VSMC phenotype provides a promising therapeutic target for clinical treatment and drug development aimed at VSMC-driven vascular diseases in humans.