On the role of pleiotrophin and its receptors in development and angiogenesis

Abstract

The secreted growth factor pleiotrophin (PTN) is expressed in all species and is evolutionary highly conserved, suggesting that it is significant for the regulation of important processes. The observation that it is highly expressed at early stages during development and at embryonic progenitor cells, highlights a potential important contribution to development. There is ample evidence for the role of PTN in the development of the nervous system and hematopoiesis, some but still not conclusive evidence for its role in the skeletomuscular system and limited evidence for its role in the development of other organs. Studies on its role in the cardiovascular system and angiogenesis suggest that PTN has a significant regulatory effect by acting on endothelial cells, while its role in smooth or cardiac muscle cells’ functions has not been studied. This review highlights what is known up to date on the role of PTN in the development of various organs and in angiogenesis. Wherever known, evidence on the crosstalk among the receptors that mediate PTN’s functions is also quoted, highlighting the complex regulatory pathways that affect development and angiogenesis.