lncRNA Function and Mechanisms during Cardiac Development and Disease

ABSTRACT Cardiovascular disease remains the leading cause of death in the United States; however, the genetic causes and molecular mechanisms underlying these medical conditions have yet to be thoroughly elucidated. As a result, the identification of new therapeutic targets for the effective treatment of these diseases is urgently required. Because the majority of the genome is actively transcribed to produce a vast number of non-coding RNA transcripts, this project is focused on determining the role of long non-coding RNAs in heart disease, which is an understudied and important area of investigation. Thousands of long non-coding RNAs (lncRNAs), which are defined as non-coding RNA transcripts greater than 200 nucleotides in length, have been found to have biological activity in humans and other organisms; they are considered novel regulatory molecules of numerous physiological and pathological processes, including those in the cardiovascular system. Our earlier RNA-seq studies identified many differentially expressed lncRNAs in the hearts of patients with ischemic cardiomyopathy. One of these lncRNAs, known as large intergenic non-coding RNA-p21 (lincRNA-p21), was previously shown to be a transcriptional target of tumor protein p53 and a novel regulator of cell proliferation and apoptosis. More recently, it has been implicated in the control of the regulation of vascular remodeling responses in atherosclerosis. However, the function of lincRNA-p21 in the heart and cardiac disease remains unknown. We propose to examine the function of lincRNA-p21 in hypertrophic cardiomyopathy and cardiac regeneration. Our preliminary data using mutant mouse lines demonstrates that lincRNA-p21 is also involved in cardiac remodeling in response to pathophysiological stress. Therefore, the overall goal of this application is to clearly define the function and molecular mechanisms of lincRNA-p21 in the heart. We propose to do this by pursuing the following Specific Aims: 1) to systematically study the in vivo function of lincRNA-p21 in the heart using gain- and loss-of-function mouse models, 2) to define the molecular mechanisms by which lincRNA- p21 regulates cardiac remodeling by testing the hypothesis that this lncRNA alters cardiac function by affecting the expression and function of Kap1/Trim28-dependent genes, and 3) to examine the therapeutic potential of lincRNA-p21 in treating cardiomyopathy using adeno-associated virus (AAV) vectors to either overexpress, or AAV/gapmers to knockdown this lncRNA, in mice with cardiomyopathy. As a result, this proposal will systematically and rigorously assess the role of lincRNA-p21 in heart disease and establish the molecular mechanisms underlying the function of this intriguing lncRNA. The information obtained from these studies are anticipated to identify important new molecular targets for the therapeutic treatment of cardiac disease.