Molecular mechanism of activation of endothelial cells involved in early stage of atherosclerosis formation.

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We have studied Molecular mechanism of activation of endothelial cells involved in early stage of atherosclerosis formation and obtained following results.(1) Oxidization of low density lipoprotein (LDL) has been demonstrated in atherosclerossis formation by laboratories around the world including us. We have found existence of its soluble form of LOX-1, which we had identified as a oxidized LDL receptor on endothelial cells. We also found the mechanism of glycation of LOX-1 and demonstrated the importance of the glycation in the LOX function.(2) Lysophosphatidylcholine (LPC) which was produced during the process of LDL oxidization enhanced expression of several genes involved in atherosclerosis formation via Egf-1 expression.(3) We identified a novle oxidized LDL receptor named SR-PSOX.We found expression of the molecule in the atheromatous plaque and demonstrated the importance in binding of rod-shaped bacteria to endothelial cells.(4) For the formation of atherosclerosis, migration of macrophages has been shown to play a critical role. We found that a chemoattractant factor, MCP-1, employs distinct pathways of intracellular signaling for cell-attachment and migration.(5) The last step of the atherosclerosis is thrombosis formation which is triggered by platelet activation. We found that JAM, junctional adhesion molecule which we identified recently, was also expressed in platelets and phosphorylated upon platelet activation. Furthermore, we have established a semi-intact system for platelet aggregation and granule secretion. We demonstrated that thje involvement of small GTPase Rho in aggregation and Rab4 in a-granule secretion.These results were presented in many international scientific meeting such as the International Atherosclerosis Meeting, European Life Science Meeting, and American Heart Association Meeting.