Epigenetic Regulation of Pre-and Post-Translational Signaling in Aortic Valve Stenosis

About This Grant

Project Summary/Abstract Calcific Aortic Valve Disease (CAVD) will affect 3% of people over the age of 75. CAVD disease progression is characterized by an active deposition of calcific noduli and extracellular matrix proteins. This excessive deposition results in valvular thickening, outflow tract narrowing, restricted blood flow, left ventricular hypertrophy, and eventual heart failure. Despite the clinical significance of this disease, patients must “watch and wait” until surgical AV replacement and repair is necessary, as currently no pharmacotherapeutics exist. This proposal focuses on identifying novel epigenetic mechanisms underlying calcific aortic valve disease progress and pathophysiology. For preliminary investigation on the role of epigenomic regulators in valve calcification, we re-mined proteomic datasets to specifically probe differential abundance of epigenetic factors – that is, proteins involved in histone post-translational modification reading, writing, and erasing. The preliminary data presented in this proposal shows that enzymes responsible for histone regulation are differentially abundant in valvular tissue as a function of disease stage, structural localization within the valve leaflet, as well as within VIC cultures as a function of calcification induction media (inorganic vs. organic phosphate media). However, the dataset mined was not exhaustive in identification as it was untargeted. Additionally, our preliminary data did not investigate the regulatory role epigenetics plays in downstream translational and post-translational signaling required for cell-cell, cell-matrix, and cell-vesicle mediated signaling. The proposed research capitalizes on an ever-expanding cohort of clinically defined human adult CAVD aortic valve tissue, as well as an extensive biobank of valvular interstitial cells isolated from human donors. It is our central hypothesis that there are unique histone modifications that contribute to pathological development of calcification in human aortic valves. Aim 1 will use novel mass spectrometry approaches to define the histone code of CAVD along with corresponding transcriptional regulation via Chromatin Immunoprecipitation sequencing. Aim 2 will determine cell-mediated spatially localized translational targets downstream of epigenetic regulation, utilizing multi-modal histopathological imaging, laser capture microdissection, and low-input proteomic strategies. Aim 3 will investigate the role of epigenomic modifications on microenvironment signaling mediated by N-linked glycosylation. By mapping the histone code of aortic valve calcification and identifying both upstream epigenetic regulators and downstream transcriptional, translational, and post-translational targets of this epigenetic regulation, we aim to identify potential pharmacotherapeutic targets that may halt progression of CAVD. These studies will be conducted by Dr. Clift under the mentorship of Dr. Elena Aikawa, a pioneer in cardiovascular systems biology, as well as an advisory committee dedicated to proposed research and trainee. By utilizing this mentorship and professional development via the MOSAIC UE5, Dr. Clift is primed for successful independence.