Figure 1From: TNF-α promotes cerebral pericyte remodeling in vitro, via a switch from α1 to α2 integrins Extracellular matrix (ECM) substrates differentially regulate cerebral pericyte behavior. (A) Phase pictures showing pericyte adhesion and morphology on collagen I, collagen IV, fibronectin, HSPG, and laminin-1 after 1 and 4 hours. Scale bar = 100 μm. Note that pericytes attached well to fibronectin and the collagens but very poorly to HSPG. (B) Time course of pericyte adhesion to different ECM substrates over 8 hours. Adhesion assays were performed as described in the text, and all points represent the mean ± SEM of four experiments. Note that after 1 hour, the number of adherent pericytes was >90% on fibronectin, approximately 40% on collagens, approximately 10% on laminin-1, but less than 1% on HSPG. * P<0.01, ** P<0.001. (C) Influence of ECM substrates on pericyte proliferation. Proliferation assays were performed as described in the text, and all points represent the mean ± SEM of four experiments. Note that fibronectin strongly promoted (** P<0.01), whereas laminin-1 (* P<0.05) and HSPG (** P<0.01) inhibited pericyte proliferation. (D) Influence of ECM substrates on pericyte migration. Migration assays were performed as described in the text, and all points represent the mean ± SEM of four experiments. Note that pericyte migration was promoted most strongly by collagen I (*** P<0.001) and to a lesser degree by fibronectin (** P<0.01) and laminin-1 (* P<0.02).Back to article page