Abstract Body (Do not enter title and authors here): Background:
The phenotypic switching of vascular smooth muscle cells (VSMCs) plays a crucial role in human occlusive vascular diseases. VSMC phenotype is regulated by specific cis-regulatory elements and their associated transcription factors (TFs). However, significant gaps remain in our identification of the specific factors that control VSMC phenotype.
Methods and Results:
To identify novel TFs involved in VSMC phenotype regulation, we re-analyzed publicly available single-cell epigenomic and transcriptomic datasets from human and mouse atherosclerotic arteries. This analysis identified TEAD TFs as potential key regulators of the VSMC phenotype associated with cardiovascular disease. Among the four TEAD family TFs, TEAD1 and TEAD3 are highly expressed in VSMCs, with TEAD3 being restricted to VSMCs and markedly reduced in phenotypically modulated cells. The VSMC-specific expression of TEAD3 is confirmed by novel Tead3 knock-in (KI) lacZ reporter and epitope tag KI mouse models.
To investigate the functional roles of TEAD1 and TEAD3, we generated VSMC-specific Tead1 and Tead3 single- and double-knockout (dKO) mice using Itga8-CreERT2. Three months after gene deletion, Tead1/3 dKO mice exhibited pronounced artery elongation, aortic wall thickening, spontaneous neointima formation, and unexpectedly severe coronary artery vasculopathy with impaired arterial contractility. In contrast, single deletion of either Tead1 or Tead3 resulted in no overt vascular phenotype. Furthermore, bulk RNA sequencing of Tead1/3-deficient aortas revealed reduced expression of contractile genes and upregulation of pro-inflammatory genes. Single-cell multi-omics analysis (snRNA-seq and snATAC-seq) further demonstrated downregulation of VSMC-specific genes, associated with decreased chromatin accessibility in regulatory regions at these genes in dKO aortas. In coupled with CUT&Tag, BioChIP-seq of endogenous TEAD3 in VSMCs revealed its occupancy at promoters and enhancers of many well-characterized SM-specific genes in the mouse aorta.
Conclusions:
These findings uncover a previously unrecognized critical role for TEAD TFs in maintaining the contractile phenotype of VSMCs and vascular homeostasis, through directly regulating a subset of smooth muscle-specific contractile genes. Our study advances our understanding of the mechanisms regulating VSMC phenotype and highlights a promising therapeutic target for treating VSMC-driven vascular diseases in humans.