Differential expression and secretion of microRNAs by specific cardiac fibroblast phenotypes

The heart is composed of many cells types, out of which cardiac myocytes and fibroblasts form the majority. Cardiac myocytes are the muscle cells, which are responsible for the rhythmic beating of the heart. Fibroblasts produce proteins which maintain the architecture of the heart. However, after heart attack whereby muscle cells are lost (infarction), fibroblasts modify themselves to become myofibroblasts. These cells produce collagen that helps to form a scar but also may impede the proper function of muscle cells. Recent advances in science have revealed a new component in cells called miRNAs. These miRNAs are short RNA molecules, which have the capacity to regulate protein production. More than 1000 short RNA molecules have been identified some of which can be released outside cells and are thought to be involved in communication between fibroblasts and cardiac myocytes. In this project, we will investigate the complete pool of miRNAs produced and released by fibroblasts and myofibroblasts cultured outside the heart. Identification of miRNAs produced by specific fibroblast cell types provides us with a tool to study miRNA profiles in fibroblasts present in different regions of the infarcted heart and their contribution to the function of the heart after myocardial infarction.