Antiphospholipid syndrome (APS) is an autoimmune disease, characterized by recurrent thrombosis in presence of circulating antiphospholipid antibodies (aPL). aPL activate endothelial cells (ECs) by up-regulating adhesion molecules, IL-6 production and modulating prostaglandin metabolism. Among aPL, anti-beta2-glycoprotein I antibodies (anti-beta2-GPI) have been shown to induce NF-kappaB nuclear translocation leading to a pro-inflammatory endothelial cell phenotype and thereby inducing acute phase proteins, such as serum amyloid A (SAA). SAA is a cytokine, a marker of inflammation and a predictor of cardiovascular disease.
SAA has been shown to bind the same receptor used by the anti-inflammatory lipid mediator Lipoxin A4 (LXA4) and elicit opposing pro-inflammatory effects. An association was found between elevated levels of anti-SAA antibodies and aortic stenosis, deep vein thrombosis, and systemic lupus erythematosus. It is largely unclear how SAA may play a role in pro-thrombotic events. The objective of t his proposal is to understand the role of anti-beta2-GPI antibodies and SAA in activating pro-thrombotic inflammatory responses in the endothelium and to determine the inhibitory effects by which LXA4 could counteract these molecular signaling pathways.
Our hypothesis states that anti-beta2-GPI antibodies and SAA play relevant roles in the regulation of NF-kappaB, AP-1 and Egr-1. We will use primary ECs and endothelial cell lines to determine the molecular events by which anti-beta2-GPI antibodies and SAA i n presence and absence of LXA4 affect the transcriptional regulation of target genes (such as IL-6, IL-8, tissue factor). We will also determine whether anti-SAA autoantibodies are associated with cardiovascular inflammation in autoimmune diseases. In summary, results from the proposed study have a potential for providing a novel therapeutic approach to treatment of inflammatory events related to cardiovascular manifestations of autoimmune diseases.
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