Abstract 67: The Novel Role of the Matricellular Protein Cyr61 in the Extracellular Matrix Bridging LPA and Integrin Signaling Pathways Leading to Smooth Muscle Cell Migration
Lysophosphatidic acid (LPA), a potent bioactive lipid, markedly induces smooth muscle cell (SMC) migration. We identified a novel function of the de novo synthesized matricellular protein Cyr61, which bridges LPA and integrin signaling pathways leading to cell migration. LPA transiently and markedly induced Cyr61 mRNA expression and the temporal and spatial expression of Cyr61 proteins in SMCs. The de novo synthesized Cyr61 proteins promptly accumulate in the Golgi apparatus and then translocate to the extracellular matrix. Using primary SMCs from LPA receptor knockout mice, we identified that LPA1 receptor is required for LPA-induced Cyr61 expression. Neutralization or knockdown of Cyr61 protein expression blocked LPA-induced cell migration, indicating the novel regulatory role of the induced matricellular protein Cyr61 in LPA-induced cell migration. LPA induces the activation of intracellular focal adhesion kinase (FAK) in SMCs. Interestingly, 1) knockdown of Cyr61 blocked LPA-induced cellular FAK activation and cell migration, and 2) knockdown of the expression of integrins alpha6, beta1 and beta3 prevented LPA or Cyr61-induced FAK activation and cell migration. These data reveal for the first time that a novel LPA/Cyr61 pathway controls cell migration and that the matricellular protein Cyr61 bridges LPA signaling and integrin signaling, which, in turn, activates FAK leading to cell migration.
- © 2013 by American Heart Association, Inc.