Search

Activated fibroblasts, also known as myofibroblasts, are mediators of several major human pathologies including proliferative fibrotic disorders, invasive tumor growth, rheumatoid arthritis, and atherosclerosis. We previously identified Niemann-Pick type C2 (NPC2) protein as a negative regulator of fibroblast activation (Csepeggi, C., Jiang, M., Kojima, F., Crofford, L. J., and Frolov, A. (2011) J. Biol. Chem. 286, 2078–2087). Here we report that NPC2-deficiency leads to a dramatic up-regulation of the arachidonic acid (AA) metabolic pathway in human fibroblasts. The major enzymes in this pathway, cPLA2 type IVA, COX-2, and mPGES-1, were dramatically up-regulated at both the transcriptional and translational levels. The specific phenotypic changes resulted in a >10-fold increase in the production and secretion of a key modulator of inflammation and immunity, prostaglandin E2. More importantly, AA metabolome profiling by liquid chromatography/tandem mass-spectrometry revealed the very specific nature of prostaglandin E2 up-regulation as the other analyzed AA metabolites derived from the COX-2, cytochrome P450, 5/15-lipoxygenase, and non-enzymatic oxidative pathways were mostly down-regulated. Blocking activity of cPLA2 efficiently suppressed expression of inflammatory cytokines, IL-1β and IL-6, thereby identifying cPLA2 as an important regulator of the inflammatory program in NPC2-null cells. Altogether, these studies highlight NPC2 as a specific regulator of AA metabolism and inflammation that suggests potential for NPC2 protein or its related signaling in the treatment of inflammatory diseases characterized by the presence of activated fibroblasts. Background: NPC2 is a protein that negatively regulates fibroblast activation. Results: NPC2-null human fibroblasts display induction of cPLA2, COX-2, and mPGES-1 expression that may contribute to the observed robust and selective activation of PGE2 biosynthesis. Conclusion: NPC2 may regulate the activated fibroblast inflammatory program through modulation of a cPLA2-dependent biosynthetic pathway. Significance: NPC2 may represent a novel therapeutic tool for the treatment of inflammatory diseases.

The use of drug-eluting stents (DESs) in primary percutaneous coronary intervention (PPCI) has shown early benefit over bare-metal stents (BMSs) in decreasing adverse cardiac events. However, there are concerns regarding the increased risk of late and very late stent thrombosis (ST) after DES use. With the paucity of ST events individual trials may have been underpowered to detect significant differences. We sought to perform a meta-analysis to evaluate the available literature examining the outcomes of DESs and BMSs in PPCI after ≥3 years of follow-up. We analyzed 8 randomized clinical trials (RCTs) and 5 observational studies comparing DESs to BMSs in PPCI. Clinical end-point data were analyzed for RCTs and observational studies separately using random-effect models. RCTs included 5,797 patients in whom first-generation DESs (sirolimus- or paclitaxel-eluting stents) were compared to BMS control arms. Patients receiving DESs had a significantly lower risk of target lesion revascularization (odds ratio [OR] 0.48, confidence interval [CI] 0.37 to 0.61), target vessel revascularization (OR 0.53, CI 0.42 to 0.66), and accordingly major adverse cardiac events (OR 0.69; CI 0.56 to 0.84). Incidence of ST was not different between groups (OR 1.02, CI 0.76 to 1.37). There was no significant difference in mortality (OR 0.88, CI 0.68 to 1.12) or recurrent myocardial infarction (OR 0.97; CI 0.61 to 1.54). Among observational studies (n = 4,650) fewer studies reported on target lesion revascularization and target vessel revascularization, but the trend remained in favor of DESs. A small but statistically significant increase in ST was noted with DES use (OR 1.62, CI 1.18 to 2.21) at ≥3 years of follow up, without evidence of recurrent myocardial infarction. Those receiving DESs had a significantly lower mortality compared to those receiving BMSs (OR, 0.65, 95% CI 0.53 to 0.80, p