Inhibition of hypoxia-induced calcium responses in pulmonary arterial smooth muscle by acetazolamide is independent of carbonic anhydrase inhibition.

Matrix metalloproteinases (MMPs), a family of extracellular endopeptidases, are implicated in angiogenesis because of their ability to selectively degrade components of the extracellular matrix. Interleukin-1beta (IL-1beta), increased in the heart post-myocardial infarction (post-MI), plays a protective role in the pathophysiology of left ventricular (LV) remodeling following MI. Here we studied expression of various angiogenic genes affected by IL-1beta in cardiac microvascular endothelial cells (CMECs) and investigated the signaling pathways involved in the regulation of MMP-2. cDNA array analysis of 96 angiogenesis-related genes indicated that IL-1beta modulates the expression of numerous genes, notably increasing the expression of MMP-2, not MMP-9. RT-PCR and Western blot analyses confirmed increased expression of MMP-2 in response to IL-1beta. Gelatin in-gel zymography and Biotrak activity assay demonstrated that IL-1beta increases MMP-2 activity in the conditioned media. IL-1beta activated ERK1/2, JNKs, and protein kinase C (PKC), specifically PKCalpha/beta(1), and inhibition of these cascades partially inhibited IL-1beta-stimulated increases in MMP-2. Inhibition of PKCalpha/beta(1) failed to inhibit ERK1/2. However, concurrent inhibition of PKCalpha/beta(1) and ERK1/2 almost completely inhibited IL-1beta-mediated increases in MMP-2 expression. Inhibition of p38 kinase and nuclear factor-kappaB (NF-kappaB) had no effect. Pretreatment with superoxide dismutase (SOD) mimetic, MnTMPyP, increased MMP-2 protein levels, whereas pretreatment with SOD and catalase mimetic, EUK134, partially inhibited IL-1beta-stimulated increases in MMP-2 protein levels. Exogenous H(2)O(2) significantly increased MMP-2 protein levels, whereas superoxide generation by xanthine/xanthine oxidase had no effect. This in vitro study suggests that IL-1beta modulates expression and activity of MMP-2 in CMECs.