Abstract
oxLDL peptide vaccine and its antibody adoptive transferring have shown a significantly preventive or therapeutic effect in atherosclerotic animal model. The molecular mechanism behind this is obscure. Here, we report that oxLDL induces MCP‐1 release in monocytes/macrophages through their TLR‐4 (Toll‐like receptor 4) and ERK MAPK pathway and is calcium/potassium channel‐dependent. Using blocking antibodies against CD36, TLR‐4, SR‐AI and LOX‐1, only TLR‐4 antibody was found to have an inhibitory effect and ERK MAPK‐specific inhibitor (PD98059) was found to have a dramatic inhibitory effect compared to inhibitors of other MAPK group members (p38 and JNK MAPKs) on oxLDL‐induced MCP‐1 release. The release of cytokines and chemokines needs influx of extracellular calcium and imbalance of efflux of potassium. Nifedipine, a voltage‐dependent calcium channel (VDCC) inhibitor, and glyburide, an ATP‐regulated potassium channel (K+ ATP) inhibitor, inhibit oxLDL‐induced MCP‐1 release. Potassium efflux and influx counterbalance maintains the negative potential of macrophages to open calcium channels, and our results suggest that oxLDL actually induces the closing of potassium influx channel – inward rectifier channel (Kir) and ensuing the opening of calcium channel. ERK MAPK inhibitor PD98059 inhibits oxLDL‐induced Ca2+/Kir channel alterations. The interfering of oxLDL‐induced MCP‐1 release by its monoclonal antibody is through its FcγRIIB (CD32). Using blocking antibodies against FcγRI (CD64), FcγRIIB (CD32) and FcγRIII (CD16), only CD32 blocking antibody was found to reverse the inhibitory effect of oxLDL antibody on oxLDL‐induced MCP‐1 release. Interestingly, oxLDL antibody specifically inhibits oxLDL‐induced ERK MAPK activation and ensuing Ca2+/Kir channel alterations, and MCP‐1 release. Thus, we found a molecular mechanism of oxLDL antibody on inhibition of oxLDL‐induced ERK MAPK pathway and consequent MCP‐1 release.
Highlights
Atherosclerosis is an inflammatory disease induced by imbalance of lipid metabolism – hyperlipaemia [1]
Results oxLDL induces monocyte/macrophage MCP-1 release through TLR-4- and MAPK-dependent pathways oxLDL-containing human serum and oxLDL (30 mg/ml) in the presence of 10% foetal bovine serum (FBS) both induced CD14+ monocyte/macrophage MCP-1 release (Fig. 1A and Figure S5), whereas human serum treated in an oxLDL antibody-conjugated agarose column, named oxLDL(-) serum, had no effect (Fig. 1A)
To test which receptor mediated the oxLDL-induced MCP-1 release, we explored blocking antibodies against CD36, TLR-4, SR-AI and LOX-1
Summary
Atherosclerosis is an inflammatory disease induced by imbalance of lipid metabolism – hyperlipaemia [1]. Oxidation of low-density lipoprotein (oxLDL) induced macrophage uptake and foam cell formation, and T cell reaction and even antibody production by B cells [2,3,4]. Cytokine expression in arteriosclerotic animal model serum has a Th1 immune profile. Atherosclerosis is regarded as an autoimmune disease [5]. Vaccination of oxLDL peptide or adoptive transfer of antibodies against oxLDL to arteriosclerotic animal model has exhibited preventive or therapeutic effects [6]. Macrophage staining and MCP-1 release assay have shown that inflammation decreased after oxLDL antibody treatment. The molecular mechanisms of antibody regulation of inflammatory reaction are less obvious
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
