Involvement of native TRPC3 proteins in ATP-dependent expression of VCAM-1 and monocyte adherence in coronary artery endothelial cells.
Background- Vascular cell adhesion molecule-1 (VCAM-1) is critical in monocyte recruitment to the endothelium, a key event in development of atherosclerotic lesions. Stimulation of human coronary artery endothelial cells (HCAECs) with ATP positively modulates VCAM-1 expression and function through a mechanism involving Ca(2+) signaling. We here examined the role of Ca(2+) influx and native TRPC3 channels in that mechanism.


RESULTS
Omission of extracellular Ca(2+) or pretreatment of cells with channel blockers markedly reduced ATP-induced VCAM-1 and monocyte adhesion. Using a siRNA strategy and real-time fluorescence, we found that native TRPC3 proteins contribute to constitutive and ATP-regulated Ca(2+) influx. ATP-dependent upregulation of VCAM-1 was accompanied by an increase in basal cation entry and TRPC3 expression. Notably, TRPC3 knock-down resulted in a dramatic reduction of ATP-induced VCAM-1 and monocyte adhesion.


CONCLUSIONS
These findings indicate that in HCAECs, native TRPC3 proteins form channels that contribute to constitutive and ATP-dependent Ca(2+) influx, and that TRPC3 expression and function are fundamental to support VCAM-1 expression and monocyte binding. This is the first evidence to date relating native TRPC3 proteins with regulated expression of cell adhesion molecules in coronary endothelium, and suggests a potential pathophysiological role of TRPC3 in coronary artery disease.
Smedlund
Kathryn
K
Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, University of Toledo College of Medicine, Health Science Campus, Ohio 43614, USA.
Vazquez
Guillermo
G
D000255:Adenosine Triphosphate / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D003324:Coronary Artery Disease / Q000378:metabolism; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D050052:TRPC Cation Channels / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D020298:U937 Cells; D015854:Up-Regulation; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism*
D002121:Calcium Channel Blockers; D034741:RNA, Small Interfering; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D000255:Adenosine Triphosphate