Mechanical strain induces monocyte chemotactic protein-1 gene expression in endothelial cells. Effects of mechanical strain on monocyte adhesion to endothelial cells

Abstract Monocyte chemotactic protein-1 (MCP-1), a potent monocyte chemoattractant secreted by endothelial cells (ECs), is believed to play a key role in the early events of atherogenesis. Since vascular ECs are constantly subjected to mechanical stresses, we examined how cyclic strain affects the expression of the MCP-1 gene in human ECs grown on a flexible membrane base deformed by sinusoidal negative pressure (peak level, −16 kPa at 60 cycles per minute). Northern blot analysis demonstrated that the MCP-1 mRNA levels in ECs subjected to strain for 1, 5, or 24 hours were double those in control ECs ( P P P 2+ chelator BAPTA/AM strongly suppressed the strain-induced MCP-1 mRNA. Verapamil, a Ca 2+ channel blocker, greatly reduced MCP-1 mRNA levels in both strained and unstrained ECs. These results indicate that mechanical strain can stimulate monocyte chemotaxis and adhesion by increasing MCP-1 gene expression in ECs. This increased gene expression is predominantly mediated via the protein kinase C pathway and requires Ca 2+ influx. Such strain-induced MCP-1 expression might contribute to the trapping of monocytes in the subendothelial space. Strain-induced gene expression might provide a molecular mechanism for the role of hypertension in atherogenesis.