Endothelial Cells: A Key Player in Angiogenesis and Lymphangiogenesis

Abstract

Endothelial cells (EC) constitute the linings of the entire vascular system including blood and lymphatic vessels. The vascular and lymphatic ECs are essential for angiogenesis and lymphangiogenesis as versatile and multifunctional organs. The EC heterogeneity in different microenvironment determines the complexity and diversity of its functions in the regulation of angiogenic and lymphangiogenic processes. In fact, many molecular regulators and signaling pathways are involved in these processes. In addition to VEGF, other angiogenic factors including FGF, HGF, TSP-1, endostatin and phospholipids such as lysophosphatidic acid all act on the ECs directly or indirectly by inducing the expression of angiogenic factors. Furthermore, it should be noted that the dynamic balance between proangiogenic and antiangiogenic factors determines the angiogenic switch and process through such signaling pathways as notch and ephrin B2, in which angiogenic receptors may serve as a key axis. Up to date, many questions still remain to be answered. However, the answers to these questions will aid in understanding the cellular and molecular mechanisms of angiogenesis and lymphangiogenesis. Elucidating these mechanisms will aid in finding novel therapeutic strategies against cancer, ischemic cardiovascular diseases, cardiovascular complications of diabetes, and obesity.