• Identification of Anti-Beta2 Glycoprotein I Auto-antibody Regulated Gene Targets in the Primary Antiphospholipid Syndrome Using Gene Microarray Analysis

      Frampton, G.; Murphy, John; Hamid, Colleen G. (University of Wolverhampton, 2007-10)
      Anti-Beta2-Glycoprotein I antibodies (anti-2GPI) are strongly associated with thrombosis in patients with primary antiphospholipid syndrome (PAPS). Anti-2GPI activate endothelial cells (EC) resulting in a pro-thrombotic and pro-inflammatory phenotype. In order to characterise EC gene regulation in response to anti-2GPI, early global gene expression was assessed in human umbilical vein endothelial cells (HUVEC) in response to affinity purified anti-2GPI. Sera were collected from patients with PAPS and IgG was purified using HiTrap Protein G Sepharose columns. Polyclonal anti-2GPI were prepared by passing patient IgG through NHS activated sepharose coupled to human 2GPI. Anti-2GPI preparations were characterized by confirming their 2GPI co-factor dependence, binding to 2GPI and ability to induce leukocyte adhesion molecule expression and IL-8 production in vitro. Two microarray experiments tested differential global gene expression in 6 individual HUVEC donors in response to 5 different PAPS polyclonal anti-2GPI (50 mg/ml) compared to 5 normal control IgG (50 mg/ml) after 4 hours incubation . Total HUVEC RNA was extracted and cRNA was prepared and hybridised to Affymetrix HG-133A (Exp.1) and HG-133A_2 (Exp.2) gene chips. Data were analyzed using a combination of the MAS 5.0 (Affymetrix) and GeneSpring (Agilent) software programmes. Significant change in gene expression was defined as greater than two fold increase or decrease in expression (p<0.05). Novel genes not previously associated with PAPS were induced including chemokines CCL20, CXCL3, CX3CL1, CXCL5, CXCL2 and CXCL1, the receptors Tenascin C, OLR1, IL-18 receptor 1 and growth factors, CSF2, CSF3, IL-6, IL1 and FGF18. Downregulated genes were transcription factors/signaling molecules including ID2. Microarray results were confirmed for selected genes (CSF3, CX3CL1, FGF18, ID2, SOD2, Tenascin C) using quantitative real-time RT-PCR analysis. This study revealed a complex anti-2GPI-regulated gene expression profile in HUVEC in vitro. The novel chemokines and pro-inflammatory cytokines identified in this study may contribute to the vasculopathy associated with PAPS.