Friday, October 28, 2011
Hall 1-2 (San Jose Convention Center)
Angiogenesis and vasculogenesis are critical for embryonic development, as well as, for a number of pathological conditions such as diabetes, tumor growth and some forms of blindness. One crucial angiogenic pathway involves the signaling molecule Vascular Endothelial Growth Factor (VEGF), which is fundamental in several of the aforementioned processes. The paracrine signaling functions of VEGF have been well studied, but currently new evidence has demonstrated the surprising importance of autocrine signaling. Using an endothelial cell VEGF-knockout mouse model, a recent study showed that endothelial cells require cell autonomous VEGF signaling for survival. While it is clear that VEGF is synthesized and transported through the secretory pathway, the specific compartment(s) where activation of VEGFR2 takes place is unknown. To answer these questions, we used immunocytofluorescence to explore the intracellular localization of a tagged VEGF construct in immortalized mouse endothelial cells (IMECs). This in vitro assay should allow us to determine if VEGF co-localizes with its receptor and/or specific vesicular compartments (endosomes, ER, Golgi, etc.). Preliminary results indicate vesicular localization corresponding to either endosomes, Weibel-Palade bodies or possibly mitochondria. Due to the use of immortal endothelial cells, we will perform ELISA protein assays to analyze intracellular VEGF retention in order to establish the endothelial-cell phenotype. The results of this study will aid in determining the function of the VEGF autocrine signaling pathway, thus illuminating a further role of VEGF in endothelial cell homeostasis and pathology.