Functional role and microfluidic gene chip analysis of proangiogenic chemokines in the course of ischemia-dependent endothelial progenitor cell (EPC) vasculogenesis

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Endothelial progenitor cells (EPCs) have been shown to amply contribute to the revascularization of ischemic areas. The discovery of EPCs has substantively altered our view of adult tissue angiogenesis, indicating that bone marrow-derived cells can contribute to new blood vessel formation. However, after 10 years of vigorous research no consensus about the appearance of EPCs has been reached yet. It is widely accepted that EPCs promote angiogenesis and vasculogenesis by virtue of the release of paracrine angiogenic factors which they carry with them as cargo. One of these angiogenic factors and my focus of interest is the pleiotropic cytokine macrophage migration inhibitory factor (MIF). Based on the recent discovery that MIF exhibits chemokine-like functions and interacts as a non-cognate interaction of the CXC chemokine receptor CXCR4, a major receptor regulating progenitor cell migration that is also expressed on EPCs, it has been shown that MIF contributes to ischemia-dependent recruitment of EPCs. Based on these results I now want to clarify the functional role of proangiogenic chemokines, such as MIF and CXCL12 after hypoxia dependent induction in endothelial cells and EPCs. Furthermore chemokine-cytokine-multiplex assays, static adhesion experiments and dynamic transmigration assays (chemotaxis) will be performed to functional underlie the role of the MIF/CXCR4 axis and CXCL12/CXCR4 axis vice versa. To answer fundamental questions regarding the nature of the heterogeneous EPCs, an innovative approach to single cell analysis utilizing single cell FACS sorting and commercially available microfluidic-based technology to perform quantitative PCR gene expression analysis across 48 gene targets simultaneously for many individual cells within a given cell population will be developed. A last step of the program deals with another innovative approach of genetically modified free flaps for tissue transfer to expand the clinical spectrum of my research portfolio.