Downregulation of VEGF-D expression by interleukin-1beta in cardiac microvascular endothelial cells is mediated by MAPKs and PKCalpha/beta1

Interleukin-1beta (IL-1beta) is a proinflammatory cytokine increased in the heart following myocardial infarction. Vascular endothelial growth factors (VEGFs) are implicated in angiogenesis due to their involvement in the recruitment and proliferation of endothelial cells. Here we studied expression of VEGFs in response to IL-1beta in rat cardiac microvascular endothelial cells (CMECs) and investigated the signaling pathways involved in the regulation of VEGF-D. cDNA array analysis indicated that IL-1beta modulates the expression of numerous angiogenesis-related genes, notably decreasing the expression of VEGF-D. RT-PCR and Western blot analyses confirmed decreased expression of VEGF-D in response to IL-1beta. IL-1beta decreased the expression of VEGF-C to a lesser extent with no effects on VEGF-A or -B. Inhibition of ERK1/2, JNKs, or PKCalpha/beta1 alone partially inhibited IL-1beta-induced VEGF-D downregulation. Concurrent inhibition of ERK1/2 or JNKs and PKCalpha/beta1 resulted in a synergistic inhibition of IL-1beta-induced decreases in VEGF-D. Inhibition of ERK1/2 partially inhibited IL-1beta-stimulated inactivation of GSK-3beta with no effect on beta-catenin levels. Inhibition of GSK-3beta using SB216763 inhibited basal VEGF-D expression. We conclude that IL-1beta downregulates VEGF-D expression in CMECs via the involvement of ERK1/2, JNKs, and PKCalpha/beta(1). This is the first report to indicate inhibition of VEGF-D gene expression in response to IL-1beta in cardiac microvascular endothelial cells, a cell type of central interest in angiogenesis.