The Role of Pericardial Cells an Drosophila melanogaster Extracellular Matrix Remodelling at the Dorsal Vessel

Abstract

The cardiovascular system of Drosophila melanogaster consists of a cardiac tube composed of myogenic cardiomyocytes and associating non-contractile pericardial cells, pumping hemolymph into the open circulatory system. The cardiac tube, known as the dorsal vessel, is embedded in a highly regulated extracellular matrix environment, required to maintain cellular integrity and cardiac function. After embryogenesis, the dorsal vessel undergoes extensive physiological changes, relying on the extracellular matrix to adapt and remodel accordingly. Three extracellular matrix proteins are investigated throughout this thesis: Type IV Collagen, Laminin and Pericardin. Due to their localization, morphology, and role in early development, the pericardial cells are candidate cells responsible for dorsal vessel extracellular matrix deposition and regulation throughout post-embryonic growth. Using immunofluorescence techniques in combination with confocal microscopy, I characterize the association between pericardial cells and extracellular matrix proteins, and quantify extracellular matrix protein deposition at the dorsal vessel throughout post-embryonic development. Gene knock-down experiments assess pericardial cell contribution to extracellular matrix synthesis and deposition at the dorsal vessel in third instar larva. Moreover, I quantify extracellular matrix protein deposition at the dorsal vessel in the absence of pericardial cells. These data suggests that pericardial cells regulate extracellular matrix protein deposition, localization and contribute to proper cardiac morphology in post-embryonic development.