Human adipocyte fatty acid-binding protein (aP2) gene promoter-driven reporter assay discriminates nonlipogenic peroxisome proliferator-activated receptor gamma ligands

Peroxisome proliferator-activated receptors (PPARs) regulate storage and catabolism of fats and carbohydrates. PPARgamma activity increases insulin sensitivity and adipocyte differentiation at the expense of adipogenesis and weight gain. The goal of this study was to 1) clone the promoter of the human adipocyte fatty acid binding protein (aP2) gene, namely fatty acid-binding protein-4, 2) characterize its pharmacological regulation, and 3) determine its putative predictability for adipogenesis. Among the selected PPAR agonists, rosiglitazone and pioglitazone displayed the highest maximal efficacy (E(max)) on reporter-gene assays in COS-7 cells cotransfected by either a galactosidase 4-response element-based or a human aP2 promoter-based Luc reporter vector, along with either chimeric or full-length human PPAR expression plasmids. The non-subtype-selective 2-(4-[2-(3-[2,4-difluorophenyl]-1-heptylureido)ethyl]phenoxy)-2-methyl-butyric acid (GW-2331) and the compounds [4-[3-(4-acetyl-3-hydroxy-2-propylphenoxy)-propoxyl]phenoxy]-acetic acid (L-165041), (4-((2S,5S)-5-(2-(bis(phenylmethyl)amino)-2-oxoethyl)-2-heptyl-4-oxo-3-thiazolidinyl)butyl)-benzoic acid (GW-0072), and indomethacin behaved as partial agonists relative to pioglitazone in full-length human aP2-PPARgamma2. Beyond their partial PPARgamma agonist properties, these compounds elicited a lower maximal up-regulation of mouse aP2 mRNA in 3T3-L1 adipocytes as compared with pioglitazone; these properties paralleled a time-dependent increase in neutral lipids. By contrast, the selective PPARalpha agonist 2,2-dichloro-12-(4-chlorophenyl)dodecanoic acid (BM-17.0744) neither stimulated the human aP2-PPARalpha promoter reporter-gene assay, thus demonstrating a specific interaction between PPARgamma and the aP2 promoter, nor affected lipogenesis in 3T3-L1 cells. Altogether, these data characterized a functional promoter of the human aP2 gene; its in vitro pharmacological regulation in PPARgamma-mediated reporter-gene assay may represent an interesting complement or an alternative to time-consuming procedures aiming at discriminating PPAR ligands with low lipogenic properties.

Cardiovascular Drugs Inhibit MMP-9 Activity from Human THP-1 Macrophages

It is now recognized that atherosclerosis complications are related to the unstable character of the plaque rather than its volume. Vulnerable plaques often contain a large lipid core, a reduced content of smooth muscle cells, and accumulation of inflammatory cells. Colocalization of macrophages and active matrix metalloproteinases (MMPs) is likely relevant for atherosclerotic lesion disruption. Nevertheless, MMP activity and regulation by cardiovascular drugs remains poorly defined. In this study, we evaluated the effects of avasimibe, fluvastatin, and peroxisome proliferator-activated receptor (PPAR) ligands on 92-kDa gelatinase B (MMP-9) secretion by human THP-1 macrophages. THP-1 macrophages were treated with compounds for 48 h, and secreted MMP-9 protein was quantified by immunoassay. Avasimibe, fluvastatin, and PPARalpha agonists (fenofibric acid and Wy-14643) significantly reduced, in a concentration-dependent manner, MMP-9 protein (up to 67 +/- 5% for fenofibric acid). In these assays, the PPARgamma selective agonist rosiglitazone displayed a lower efficacy than other compounds. Enzymatic activity of MMP-9 was also decreased by all cardiovascular drugs tested. MMP-9 protein/activity inhibition by cardiovascular drugs was due, at least in part, to a decrease in MMP-9 mRNA. These results show that THP-1 macrophages could be an useful cellular model to investigate effects of compounds on plaque vulnerability through MMP-9 activity.

PPARalpha and PPARdelta activators inhibit cytokine-induced nuclear translocation of NF-kappaB and expression of VCAM-1 in EAhy926 endothelial cells

Endothelium injury is a primary event in atherogenesis, which is followed by monocyte infiltration, macrophage differentiation, and smooth muscle cell migration. Peroxisome proliferator-activated receptors (PPARs) are transcription factors now recognized as important mediators in the inflammatory response. The aim of this study was to develop a human endothelial model to evaluate anti-inflammatory properties of PPAR activators. PPAR proteins (alpha, delta and gamma) are expressed in EAhy926 endothelial cells (ECs). Pirinixic acid (Wy-14643), fenofibrate, fenofibric acid, the Merck ligand PPARdelta activator L-165041, 15-deoxy-Delta(12,14)-prostaglandin J2, but not rosiglitazone (BRL-49653) inhibited the induced expression of vascular cell adhesion molecule-1 (VCAM-1), as measured by enzyme linked immunosorbent assay (ELISA), and monocyte binding to activated-EAhy926 cells. The PPARdelta activator L-165041 had the greatest potency to reduce cytokine-induced monocyte chemotactic protein-1 (MCP-1) secretion. All PPAR activators tested which impaired VCAM-1 expression reduced significantly nuclear p65 amount. These results show that EAhy926 endothelial cells are an adequate tool to substantiate and characterize inflammatory impacts of PPAR activators.

F 11440, a potent, selective, high efficacy 5-HT1A receptor agonist with marked anxiolytic and antidepressant potential

F 11440 (4-methyl-2-[4-(4-(pyrimidin-2-yl)-piperazino)-butyl]-2H, 4H-1,2,4-triazin-3,5-dione) was the outcome of a research effort guided by the hypothesis that the magnitude of the intrinsic activity of agonists at 5-HT1A receptors determines the magnitude of their antidepressant and anxiolytic-like effects. The affinity of F 11440 for 5-HT1A binding sites (pKi, 8.33) was higher than that of buspirone (pKi, 7.50), and somewhat lower than that of flesinoxan (pKi, 8.91). In vivo, F 11440 was 4- to 20-fold more potent than flesinoxan, and 30- to 60-fold more potent than buspirone, in exerting 5-HT1A agonist activity at pre- and postsynaptic receptors in rats (measured by, for example, its ability to decrease hippocampal extracellular serotonin (5-HT) levels and to increase plasma corticosterone levels, respectively). F 11440 did not have detectable antidopaminergic activity (unlike buspirone, which inhibited all of the directly observable behavioral effects of methylphenidate in rats), showed no evidence of antihistaminergic activity (unlike flesinoxan, which protected against the effects of a histamine aerosol in guinea pigs), and had a 70-fold separation between its 5-HT1A agonist and alpha-1 adrenergic antagonist properties (measured as the ability to inhibit the methoxamineinduced increase in blood pressure in rats), unlike flesinoxan, which showed a <3-fold separation. In HeLa cells expressing human 5-HT1A receptors, F 11440 decreased the forskolin-induced increase in AMP, and, based on its maximal effect, was found to have an intrinsic activity of 1.0 relative to that of 5-HT, which was significantly higher than that of buspirone (0.49), ipsapirone (0.46) and flesinoxan (0.93). Consistent with the aforementioned hypothesis, F 11440 produced anxiolytic- and antidepressant-like effects in animal models (i.e., increased punished responding in a pigeon conflict procedure and decreased immobility in a rat forced swimming test, respectively) that were more substantial than those of buspirone, ipsapirone and flesinoxan. Thus, F 11440, shown here to be a potent, selective, high efficacy 5-HT1A receptor agonist, appears to have the potential to exert marked anxiolytic and antidepressant activity in humans.