Defining the role of TCF21 in adventitial fibroblasts in atherosclerosis

The National Institutes of Health National Heart Lung and Blood Institute awarded The Leland Stanford Junior University $165,488 on March 5, 2026, under the Cardiovascular Diseases Research program (CFDA 93.837) to fund research defining the role of transcription factor TCF21 in adventitial fibroblasts during atherosclerosis development.

The project will characterize how TCF21 overexpression in adventitial fibroblasts affects atherosclerotic plaque formation using an adventitial fibroblast-specific TCF21 overexpression mouse model. The recipient will conduct histological analysis of plaque changes and alterations in non-adventitial fibroblast plaque cells including smooth muscle cells and inflammatory cells. Single-cell RNA sequencing will characterize transcriptional changes in adventitial fibroblasts upon TCF21 overexpression and downstream transcriptional changes in non-adventitial fibroblast plaque cells. The research will identify precise epigenetic regions of TCF21 binding to understand how TCF21 regulates inflammatory cytokine expression, with the hypothesis that TCF21 overexpression locks adventitial fibroblasts in a quiescent state to prevent plaque formation.

The award is a project grant with performance at Palo Alto, California. Period of performance runs through December 31, 2028.

Abstract

Coronary artery disease (CAD) remains a rising cause of morbidity and mortality in the united states. Human genetics suggest that a significant portion of the inheritable risk of CAD is related to fibroblast-specific regions of the genome. Using single cell transcriptomics, our group has identified a transcriptionally distinct adventitial fibroblast (advfib) population, which undergoes early phenotypic modulation during atherosclerosis development. Specific ablation of advfib significantly reduces plaque burden, suggesting their ability to influence atherosclerosis. To identify regulators of advfib, we characterized regions of altered chromatin accessibility upon advfib activation, revealing the transcription factor TCF21. TCF21 is predominantly expressed in advfib, and its expression declines upon advfib phenotypic activation. TCF21 knockout in murine advfib increases vascular calcifications and upregulation of pro-atherogenic inflammatory cytokines. Given the restricted expression of TCF21 to advfib and phenotypic activation of advfib upon TCF21 knockdown, the central hypothesis underlying this proposal is that overexpression of TCF21 locks advfib in a quiescent state, which then prevents the downstream activation of non-cell-autonomous signals that trigger plaque formation. Using an advfib-specific TCF21 overexpression mouse model, i will characterize histological changes in plaque and alterations in non-advfib plaque cells, such as smooth muscle cells and inflammatory cells. I will then use single-cell RNA sequencing to characterize transcriptional changes of advfib upon TCF21 overexpression and downstream transcriptional changes in non-advfib plaque cells. Given the putative effect of TCF21 on the activation/recruitment of inflammatory cells, my goal is to characterize the precise epigenetic regions of TCF21 binding to understand how TCF21 regulates inflammatory cytokine production. Overall, this study will elucidate the role of advfib in atherosclerosis and characterize how TCF21 regulates advfib.