Dopamine Regulates Mobilization of Mesenchymal Stem Cells during Wound Angiogenesis
Figure 5
Dopamine (DA) through its D2 receptors inhibits VEGF induced migration of BM-MSCs by regulating phosphorylation of VEGFR-2 and Akt and actin polymerization.
(A and B) Effect of DA on VEGF induced phosphorylation of VEGFR-2 and Akt in murine MSCs. Lane 1: Cells stimulated with VEGF (10 ng/ml). Lane 2: Cells pretreated with 1 µM DA before being exposed to VEGF (10 ng/ml). Lane 3: Cells treated with 100 µM eticlopride followed by DA and VEGF. Addition of DA significantly inhibited VEGF induced phosphorylation of both VEGFR-2 receptors and its downstream target Akt when compared with VEGF treated control. Pre-treatment with eticlopride, abrogated DA induced dephosphorylation of both VEGFR-2 and Akt. However, expression of total VEGFR-2 and total Akt remained unchanged. Results are representative of six separate experiments each yielding similar results. (C) In actin polymerization assay, VEGF induced MSCs showed significant polymerization of actin cytoskeleton leading to formation of F-actin. However, no such alterations were observed in case of Akt silenced MSCs which showed strikingly lower migratory activity against VEGF than normal MSCs. (D) Effect of DA on VEGF induced actin polymerization in MSCs. Treatment with 1 µM DA had significant inhibitory effect on actin polymerization dynamics in MSCs when compared to VEGF treated control. However, pre-treatment with specific DA D2 receptor antagonist eticlopride (100 µM) abrogated the DA induced changes in the actin polymerization dynamics of the VEGF induced MSCs. Original magnifications, ×1000.