Contextual Regulation of Cell Proliferation & Differentiation in Angiogenesis: Integrated Functional Genomic Discovery &Validation Approach

Angiogenesis, the formation of new blood vessels from extant vasculature, is a fundamental homeostatic process and a key factor in the progression of many pathological conditions. Angiogenesis is defined by the growth and differentiation of endothelial ce lls. We conceptualize angiogenesis as a cycle of endothelial cell differentiation. The angiogenic process transitions endothelial cells through several distinct phenotypic states each defined by specific functional, morphological and molecular traits. A k ey transition is the phenotypic switch from cell proliferation to branching morphogenesis, a process regulated by focal cell-cell contact with perivascular mural cells and extracellular matrix (ECM). These perivascular microenviromental molecular cues imp ose a contextual modulation of angiogenic endothelial cell signal transduction networks. Using a unique experimental system of co-cultured primary human endothelial and smooth muscle cells we are able to model in vitro this fundamental phenotypic switch a nd facilitate high throughput interrogation of the underlying molecular mechanisms. We will apply a novel genome-wide retroviral RNAi library screening technology, chemical genetics, state-of-the art phosphoprotein-flow cytometry (PhosphoFlow), high cont ent cellular imaging, bioinformatics analysis, novel tissue engineering-based animal model and multimodal in vivo imaging to reveal the defining contextual combinatorial signaling network changes that underpin this critical cellular decision.