ИСТИНА

Background and Aims: Atherosclerotic plaques are sites of chronic inflammation in the vessel wall, infiltrated by macrophages and T cells. Activated effector T cells are present in advanced plaques and associated with plaque progression. We showed previously, that the major stimuli for T cell activation and migration in atherosclerotic lesions include CCR5-, CX3CR1- and IL-15R-dependent signaling axes. Here, we focused on the ligand content for these receptors in plaques, employing bulk and cell population-specific qPCR. The data on ligand mRNA expression was additionally verified at protein level. Methods: Рaired specimens of atherosclerotic plaques and peripheral blood were obtained from 10 patients undergoing carotid endarterectomy. Aliquots of cell suspensions from blood and plaque tissue were frozen for bulk qPCR, the rest was surface-stained against CD3, CD45, CD31, CD64, CD68, and CD146 for subsequent sorting. Sorting of endothelial cells (CD31/CD146), monocytes/macrophages (CD64/CD68), and T cells (CD3/CD45) was performed to assess the expression of CCL3, CCL4, CCL5, CX3CL1, IL15 by TaqMan qPCR in separate populations as well as in bulk suspensions. The expression patterns of CCL3, CCL4, CCL5 were confirmed in plaques using immunohistochemistry. Results: CCL3 was the major plaque CCR5 ligand, elevated in plaques vs. blood in bulk analysis (p<0.05, Mann-Whitney test) and predominantly expressed in the macrophage compartment. CCL4 was not differentially expressed in plaques vs. blood and predominant in the T cell plaque compartment. CCL5 was elevated in blood vs. plaques (p<0.05, Mann-Whitney test) and restricted to blood T cells. CX3CL1 was elevated in plaques vs. blood cells (p<0.05, Mann-Whitney test) and predominant in the endothelial and macrophage compartment. IL15 was not differentially expressed in the studied specimens. Conclusions: Thus, we determined the differential expression of specific ligands - CCL3 (CCL4) and CX3CL1 - in atherosclerotic plaques. These signaling molecules may become novel therapeutic targets in atherosclerosis.