Role of c/ebpβ in flow-induced reprogramming of endothelial cells

The National Heart, Lung, and Blood Institute awarded Emory University $100,228 on December 15, 2026, under the Cardiovascular Diseases Research program (CFDA 93.837) to support research on the role of C/EBPB in flow-induced reprogramming of endothelial cells.

The research investigates how CCAAT/enhancer-binding protein beta (CEBPB), a transcription factor, contributes to atherosclerosis development in endothelial cells exposed to disturbed blood flow. The work encompasses characterization of CEBPB protein isoforms (LAP, LAP*, and LIP) and their roles in endothelial inflammation and endothelial-to-mesenchymal transition. Experimental approaches include RNA sequencing analysis, in vivo studies using mouse models, and cultured human aortic endothelial cell studies, with investigation of mechanisms by which CEBPB expression patterns shift in response to flow conditions.

The award extends through June 14, 2029, with place of performance in Atlanta, Georgia. This is a project grant, the assistance type supporting direct research investigation. Emory University, the recipient, is the parent entity through its Office of Sponsored Programs Division.

Abstract

Atherosclerosis is characterized by the obstruction of blood flow due to the buildup of plaque in the arterial wall. IT results in cardiovascular complications including heart attack, ischemic stroke, and peripheral arterial disease-all leading causes of death worldwide. In the presence of systemic risk factors, atherosclerosis preferentially develops at focal sites of disturbed blood flow. A single cell RNA sequencing study on a mouse partial carotid ligation model identified the differential genome-wide effects of disturbed flow and stable flow on the transcriptomic profiles of endothelial cells (ECS) in vivo. Interestingly, IT identified ccaat/enhancer-binding protein beta (cebpb) as a potential transcription factor regulating flow-induced reprogramming of ECS (fire) contributing to atherosclerosis. These reprogramming profiles include endothelial inflammation and endothelial to mesenchymal transition (endmt). Further independent in vivo studies confirmed that cebpb RNA and protein expression is upregulated in ECS exposed to disturbed flow. Cebpb is a member of the c/EBP family of leucine-zipper transcription factors, primarily associated with cell lineage determination in immune cells. Its gene is composed of a single exon, whose translation leads to one of the three protein isoforms: LAP (full-length), LAP* and LIP (truncated, lacking the activation domain) by unclear mechanisms. Previous studies have shown the importance LIP/LAP ratios in breast cancer, inflammation, and epithelial-to-mesenchymal transition (EMT). However, the role of cebpb and its protein isoforms in ECS and atherosclerosis is unknown. Remarkably, in cultured human aortic ECS (haecs), cebpb is primarily translated to LIP, and disturbed flow exposure leads to increased expression of LIP in the nucleus. Sirna-mediated cebpb knockdown inhibits endothelial inflammation, while LIP overexpression increases expression of markers of inflammation and endmt. Notably, tamoxifen-inducible EC-specific overexpression of LIP increases plaque lesions along the aorta in male mice. Given these exciting preliminary findings, i hypothesize that disturbed flow leads to nuclear localization of LIP, which promotes the expression of fire markers contributing to atherosclerosis development. The goal of this project is to uncover the role of cebpb and its protein isoform, LIP, in fire and atherosclerosis through the following two specific aims. Aim 1. To incorporate shear-stress studies, gene perturbations and functional assays, and determine how the nuclear translocation of LIP contributes to fire and endothelial dysfunction in vitro. Aim 2. To use mouse models of flow-induced atherosclerosis and gene delivery to determine how LIP regulates fire and atherosclerosis in vivo. These experiments will reveal insights into the mechanisms of cebpb-LIP in EC reprogramming and atherosclerosis. Overall, this study will increase our understanding of flow-dependent mechanisms of EC reprogramming in the onset and progression of atherosclerosis. My findings will furthermore elucidate pathways that could be targeted for anti-atherogenic therapies.