Role of Ca2+ influx in tissue factor expression in monocyte adhesion to endothelial cells

Tissue factor (TF) is the primary initiator of the coagulation cascade. Ca2+ signaling is involved in TF gene expression. Monocyte chemoattractant protein-1 (MCP-1) and its receptor (CCR2) play a pivotal role in the inflammation of atherosclerosis. Although nitric oxide (NO) impairment appears to promote thrombogenicity in monocyte adhesion to endothelial cells (ECs), little is known about its mechanism. N-omega-nitro-L-arginine methyl ester (L-NAME) promoted MCP-1 expression in EC culture. In response to monocyte adhesion, increased TF expression accompanied by NF-kappa B p65 activation was observed in L-NAME-treated ECs compared with non-treated ECs. This increased TF expression was prevented by BAPTA-AM, an intracellular Ca2+ chelator. Monocyte attachment to L-NAME- treated ECs increased Ca2+ influx compared with non-treated ECs, which was prevented by the blockade of MCPI/CCR2. These findings suggest that increased production of MCP-1 caused by L-NAME contributes to the enhancement of Ca2+ influx only when monocytes adhered to ECs and that this may accelerate TF expression in ECs triggered by monocyte adhesion. We demonstrate the role of Ca2+ influx via MCP-1/CCR2 under NO impairment in TF expression in monocyte-EC interaction.