Abstract

Objective: To determine the effects of primary antiphospholipid syndrome (PAPS)-derived anti-β₂GPI antibodies on gene expression in human umbilical vein endothelial cells (HUVEC) by gene profiling using microarrays.

Methods: Anti-β₂GPI antibodies purified from sera of patients with PAPS or control IgG isolated from normal subjects were incubated with HUVEC for 4 h before isolation of RNA and processing for hybridisation to Affymetrix Human Genome U133A-2.0 arrays. Data were analysed using a combination of the MAS 5.0 (Affymetrix) and GeneSpring (Agilent) software programmes. For selected genes microarray data were confirmed by real-time PCR analysis or at the protein level by ELISA.

Results: A total of 101 genes were found to be upregulated and 14 genes were downregulated twofold or more in response to anti-β₂GPI antibodies. A number of novel genes not previously associated with APS 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, IL1β and FGF18. The majority of downregulated genes were transcription factors/signalling molecules including ID2. Quantitative real-time RT-PCR analysis confirmed the microarray results for selected genes (CSF3, CX3CL1, FGF18, ID2, SOD2, Tenascin C).

Conclusions: This study reveals a complex gene expression response in HUVEC to anti-β₂GPI antibodies with multiple chemokines, pro-inflammatory cytokines, pro-thrombotic and pro-adhesive genes regulated by these antibodies in vitro. Some of these newly identified anti-β₂GPI antibody-regulated genes could contribute to the vasculopathy associated with this disease.