The role of monocytes Siglec-1 in stimulating CD4+and CD8+T cells proliferation and activation in atherosclerosis

Abstract

Objective To investigate the role of atherosclerotic monocytes Siglec-1 in stimulating CD4+and CD8+T lymphocytes proliferation and activation. Methods Experimental research.Cluster of differentiation antigen 14 (CD14) positive monocytes of 18 acute coronary syndrome (ACS), 41 stable angina (SA) and 32 healthy volunteers were separated by magneticactivated cell sorting.Different concentration of interferon-α (IFN-α,0,2,5,10 ng/ml) were used to up-regulate Siglec-1 and small interfering RNA (siRNA) or blocking antibody were used to downregulate Siglec-1.Then monocytes were cocultured with CD4+T/CD8+T cells from a third healthy volunteer for 5 days.The experiment was designed for 11 groups (n=10 for each group),that was (1) normal CD14,(2) normal CD14+IFN-α 5 ng/ml,(3) normal CD14+IFN-α 5 ng/ml+anti-Siglec-1 2μg/ml,(4) ACS CD14,(5) ACS CD14+control siRNA group (Mock),(6) ACS CD14+siRNA 679 40 nmol/L,(7) ACS CD14+anti-Siglec-1 2μg/ml,(8) SA CD14,(9) SA CD14+Mock,(10) SA CD14+siRNA 679 40 nmol/L and (11) SA CD14+anti-Siglec-1 2μg/ml.Cell Counting Kit-8 (CCK-8) was used to determine T cells proliferation and ELISA was used to detect Interleukin-2 (IL-2),IL-10,IL-12 and IFN-γ of culture supernatant.Data of cytokines detection were expressed as medium (quartiles) and analyzed by nonparametric rank sum test. Results By the blockage of Siglec-1 (group 6),the proliferation of CD4 and CD8 were decreased.Secretion of IL-2,IL-12 and IFN-γby CD4 cells[67.00 (62.50-87.30),0.86 (0-1.63),and 47.82 (37.60-56.67) pg/ml,respectively] were decreased and IL-10[56.00 (46.25-67.40) pg/ml] was increased compared with those in control group[group 4,213.70 (187.50-275.30),6.87 (4.90-8.93),114.90 (89.50-167.40),and 21.08 (15.70-33.20) pg/ml,respectively,with U=8.50,17.00,8.50,and 87.50,respectively.all P 0.05). Conclusions IFN-α can up-regulate monocytes Siglec-1.Siglec-1 may participate in the pathogenesis of AS via promoting proliferation of CD4+/CD8+T cells and Th1 cytokines secretion of CD4+T cells.(Chin J Lab Med,2013,36:414-419) Key words: Atherosclerosis; Sialic acid binding Ig-like lectin 1; T-lymphocytes; Cell proliferation; Cytokines