T-cadherin is a novel regulator of pericyte function during angiogenesis

Pericytes are mural cells that play an important role in regulation of angiogenesis and endothelial function. Cadherins are a superfamily of adhesion molecules mediating Ca2 thorn -dependent homophilic cell-cell interactions that control morphogenesis and tissue remodeling. To date, classical N-cadherin is the only cadherin described on pericytes. Here, we demonstrate that peri-cytes also express T-cadherin (H-cadherin, CDH13), an atypical glycosyl-phosphatidylinositol (GPI)-anchored member of the superfamily that has previously been implicated in regulation of neurite guidance, endothelial angiogenic behavior, and smooth muscle cell differentiation and progression of cardiovascular disease. The aim of the study was to investigate T-cadherin function in pericytes. Expression of T-cadherin in pericytes from different tissues was performed by immunofluorescence analysis. Using lentivirus-mediated gain-of-function and loss-of-function in cultured human pericytes, we demonstrate that T-cadherin regulates pericyte proliferation, migration, invasion, and interactions with endothelial cells during angiogenesis in vitro and in vivo. T-cad-herin effects are associated with the reorganization of the cytoskeleton, modulation of cyclin D1, a-smooth muscle actin (aSMA), integrin (33, metalloprotease MMP1, and collagen expression levels, and involve Akt/GSK3(3 and ROCK intracellular signaling pathways. We also report the development of a novel multiwell 3-D microchannel slide for easy analysis of sprouting angiogene-sis from a bioengineered microvessel in vitro. In conclusion, our data identify T-cadherin as a novel regulator of pericyte function and support that it is required for pericyte proliferation and invasion during active phase of angiogenesis, while T-cadherin loss shifts pericytes toward the myofibroblast state rendering them unable to control endothelial angiogenic behavior.