Figure 5

Identifying roles for specific β1 integrins in regulating pericyte behavior. (A) Pericyte adhesion to collagen I is mediated by the α2β1 integrin. Phase pictures showing that pericyte adhesion to collagen I was blocked by antibodies specific for β1 and α2 subunits but not by the anti-α1 integrin antibody. Scale bar = 50 μm. (B) Quantification of integrin blockade studies. Adhesion assays examining pericyte adhesion to collagen I and collagen IV were performed as described in the text, and all points represent the mean ± SEM of four experiments. Note that pericyte adhesion to collagen I and IV was blocked by antibodies specific for β1 and α2 subunits but not by the anti-α1 integrin antibody (** P<0.001). (C) Identifying pericyte integrins that mediate adhesion to fibronectin and laminin-1. Note that α5β1 integrin mediated pericyte adhesion to fibronectin, whereas adhesion to laminin-1 was mediated primarily by α1 and to a lesser degree by α6 integrin (* P<0.01, ** P<0.001). (D,E) Examining the role of α2 integrin in pericyte migration (D) and proliferation (E). Assays were performed as described in the text, and all points represent the mean ± SEM of four experiments. Note that pericyte migration and proliferation on collagen I was significantly blocked by antibodies against the β1 or α2 integrin subunits, but was not affected by the anti-α1 integrin antibody (* P<0.05, ** P<0.02, *** P<0.01).