Vascular Procr+ stem cells: Finding new branches while looking for the roots

Abstract

Generation and growth of the blood vasculature network is a highly synchronized process, requiring coordinated efforts of endothelial cells and pericytes to maintain blood vessel integrity and regeneration. In a recent paper published in Cell Research, Yu et al. identified and characterized bipotent Procr-expressing vascular endothelial stem cells, which give rise to both endothelial cells and pericytes.

Figure 1

Procr is widely expressed by stem cells in various tissues. (A) Procr is expressed by vascular endothelial stem cells (VESCs). Procr⁺ VESCs are bipotent, giving rise to endothelial cells and pericytes. (B) Procr is expressed by mammary stem cells (MaSCs), and can be differentiated into all lineages of the mammary epithelium including basal and luminal cells. (C) Procr (EPCR) is highly expressed by bone marrow hematopoietic stem cells (HSCs) located in a thrombomodulin- and aPC-enriched arterial microenvironment. EPCR signaling, manifested by aPC ligation, promotes stem cell retention in the bone marrow and protection from cytotoxic damage.