The touching story of purinergic signaling in epithelial and endothelial cells

Abstract

Endothelial and epithelial cells have something in common—they are both the barrier and bridge between different environments. Forming a one-cell layer lining of blood vessels, airways, and urinary tract, they are in constant contact with a wide variety of cells, putting high demands on the communication skills of these cells. The purinergic signaling system offers a dynamic and versatile way for local and rapid intercellular communication and involves three processes: nucleotide release, enzymatic degradation, and activation of purinergic receptors. With an impressive number of molecular members of the system (15 P2 receptor subtypes and in total 16 nucleotide-degrading enzymes), cells have managed to put purines and pyrimidines as well as their derivatives to use in an array of different areas, including regulation of flow, secretion, and vascular tone. Indeed, the purinergic signaling system is an ancient way of intercellular communication that most likely could be found in the first most primitive life form [1]. The scope of this review is to give an overview of exciting features of purinergic signaling and examples of gaps to fill in understanding its role in the cells lining the body—the endothelium and the epithelium.