Research ArticleBiochemistry

HLA Class I Molecules Partner with Integrin β4 to Stimulate Endothelial Cell Proliferation and Migration

Science Signaling  23 Nov 2010:
Vol. 3, Issue 149, pp. ra85
DOI: 10.1126/scisignal.2001158

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Abstract

Among transplant recipients, those who produce antibodies against the donor’s human leukocyte antigens (HLAs) are at higher risk for antibody-mediated rejection and transplant vasculopathy, which is a progressive, vasculo-occlusive disease that results in ischemic injury and deterioration of organ function. Antibodies against HLA class I (HLA-I) molecules are thought to contribute to transplant vasculopathy by triggering signals that elicit the activation and proliferation of endothelial cells. Here, we demonstrate a molecular association between HLA-I and the integrin β4 subunit after the stimulation of endothelial cells with HLA-I–specific antibodies. Knockdown of integrin β4 in these cells abrogated the ability of HLA-I to stimulate the phosphorylation of the kinases Akt, extracellular signal–regulated kinase (ERK), and Src, as well as cellular proliferation. Similarly, reducing the abundance of HLA-I suppressed integrin β4–mediated phosphorylation of ERK and the migration of endothelial cells on laminin-5, a component of the extracellular matrix. These results indicate a mutual dependency between HLA-I and the integrin β4 subunit to stimulate the proliferation and migration of endothelial cells, which may be important in promoting transplant vasculopathy and tumor angiogenesis.

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