Supplementary Material for: Estradiol Modulates Tumor Necrosis Factor-Induced Endothelial Inflammation: Role of Tumor Necrosis Factor Receptor 2
2012-10-23T00:00:00Z (GMT) by
The sex hormone estradiol (E2) appears to mediate both anti-atherogenic and pro-inflammatory effects in premenopausal women, suggesting a complex immunomodulatory role. Tumor necrosis factor (TNF) is a key pro-inflammatory cytokine involved in the pathogenesis of atherosclerosis and other inflammatory diseases. Alterations at the TNF receptors (TNFRs) and their downstream signaling/transcriptional pathways can affect inflammatory responses. Given this background, we hypothesized that chronic E2 exposure would alter endothelial inflammatory response involving modulation at the levels of TNFRs and signaling pathways. HUVECs were used as the model system. Pre-treatment with E2 did not significantly alter TNF-induced upregulation of pro-inflammatory molecules ICAM-1 (3–6 times) and VCAM-1 (5–7 times). However, pharmacological inhibition of transcriptional pathways suggested a partial shift from NF-ĸB (from 97 to 64%) towards the JNK/AP-1 pathway in ICAM-1 upregulation on E2 treatment. In contrast, VCAM-1 expression remained NF-ĸB dependent in both control (∼96%) and E2 treated (∼85%) cells. The pro-inflammatory TNF effects were mediated by TNFR1. Interestingly, E2 pre-treatment increased TNFR2 levels in these cells. Concomitant TNFR2 activation (but not TNFR1 activation alone) led to the shift towards JNK/AP-1-mediated ICAM-1 upregulation in E2-treated cells, suggesting the effects of chronic E2 to be dependent on TNFR2 signaling.