l-165041 and pirinixic-acid

In the present study we investigated the effect of peroxisome proliferator activated receptor (PPAR) ligands on progesterone (P4) and 17β-estradiol (E2) secretion and 3b-hydroxysteroid dehydrogenase/Δ(5)-Δ(4) isomerase (3β-HSD) mRNA abundance in porcine corpora lutea (CL) collected on days 10-12 and 14-16 of the estrous cycle or pregnancy. The PPAR agonists reduced P4 secretion by the CL during pregnancy whereas they were ineffective during the estrous cycle. An inhibitory effect of WY-14643 (PPARα agonist) on P4 release was noted on days 14-16 of pregnancy. The treatment of the CL with L-165,045 (PPARβ agonist) diminished P4 release by the tissue during both stages of pregnancy. A natural PPARγ agonist, PGJ2, reduced P4 release on days 14-16 or days 10-12 of pregnancy, respectively. Rosiglitazone (PPARγ agonist) inhibited P4 secretion by the CL on days 10-12 of pregnancy. In turn, PPARα ligands effect on E2 release was differential. While PPARγ activator diminished E2 secretion by the CL explants during all tested stages of the estrous cycle and pregnancy, PPARβ ligands did not induce any change in E2 level. In turn, PPARβ agonist reduced E2 release by the tissue during both stages of pregnancy but did not affect the secretion during the estrous cycle. In the present study there was a lack of PPAR ligands effect on 3β-HSD mRNA abundance. In summary, the results suggest that PPARs are involved in the regulation of progesterone and 17β-estradiol release by porcine CL. Porcine CL indicates a different receptivity to PPAR ligands depending on the reproductive status of animals.

Topics: 3-Hydroxysteroid Dehydrogenases; Anilides; Animals; Benzamides; Corpus Luteum; Estradiol; Estrous Cycle; Female; Gene Expression; Indoles; Ligands; Peroxisome Proliferator-Activated Receptors; Phenoxyacetates; Pregnancy; Progesterone; Prostaglandin D2; Pyridines; Pyrimidines; RNA, Messenger; Rosiglitazone; Swine; Thiazolidinediones

Peroxisome proliferator activated receptors (PPARs) are ligand-dependent transcriptional factors which are expressed in distinct tissues of the female reproductive system, including the ovary, uterus and placenta. An important role of PPARs in the regulation of reproductive processes has been previously highlighted in rodents. In the present study we investigated the in vitro effect of PPAR ligands on prostaglandin E2 (PGE2) release and prostaglandin E synthase (PGES) gene expression in the endometrial explants collected from cyclic (days 10-12 and 14-16 of the estrous cycle) or pregnant (days 10-12 and 14-16) pigs. A stimulatory (p<0.05) effect of rosiglitazone (PPARγ agonist) on PGE2 accumulation was noted during both stages of the estrous cycle and both stages of pregnancy, whereas a higher (p<0.05) PGES mRNA level was observed on days 10-12 of the estrous cycle and on days 14-16 of gestation when compared to the controls. The activation of PPARβ by L-165,041 augmented (p<0.05) PGE2 release by the endometrium on days 14-16 of the estrous cycle and on days 14-16 of pregnancy, but the increase (p<0.05) in PGES mRNA abundance was noted on days 10-12 of the estrous cycle and during both stages of pregnancy. A stimulatory (p<0.05) effect of WY-14643 (agonist) and MK 886 (antagonist) on PGE2 release was noted on days 10-12 of the estrous cycle, and days 14-16 of pregnancy, respectively. There was a lack of change in PGES mRNA abundance in the endometrium exposed to PPARα ligands. We conclude that PPARs are mediators of prostaglandin E2 synthesis/accumulation in porcine endometrium during the luteal phase of the estrous cycle and the time of periimplantation.

Topics: Animals; Dinoprostone; Endometrium; Estrous Cycle; Female; Indoles; Intramolecular Oxidoreductases; Ligands; Peroxisome Proliferator-Activated Receptors; Phenoxyacetates; Pregnancy; Prostaglandin-E Synthases; Pyrimidines; RNA, Messenger; Rosiglitazone; Swine; Thiazolidinediones

In the present study, we investigated the in vitro effects of peroxisome proliferator activated receptor (PPAR) ligands on PGF2α secretion and mRNA expression of prostaglandin F synthase (PGFS) in porcine endometrial explants collected on days 10-12 and 14-16 of the estrous cycle or pregnancy. The explants were incubated for 6h with: PPARα ligands - WY-14643 (agonist) and MK 886 (antagonist); PPARβ ligands - l-165,041 (agonist) and GW 9662 (antagonist); PPARγ ligands - 15d-prostaglandin J2 (PGJ2, agonist), rosiglitazone (agonist) and T0070907 (antagonist). The expression of PGFS mRNA in the endometrium and the concentration of PGF2α in culture media were determined by real time RT-PCR and radioimmunoassay, respectively. During the estrous cycle (days 10-12 and 14-16), the agonists - WY-14643 (PPARα), l-165,041 (PPARβ), PGJ2 and rosiglitazone (PPARγ) - increased PGF2α secretion but did not affect PGFS mRNA abundance. During pregnancy (days 10-12 and 14-16), PPARα and PPARγ ligands did not change PGF2α release, whereas PPARβ agonist augmented PGF2α release on days 14-16 of pregnancy. In addition, WY-14643 and l-165,041 increased PGFS mRNA level in both examined periods of pregnancy. PPARγ agonist (PGJ2) and antagonist (T0070907) enhanced PGFS mRNA abundance in the endometrium on days 10-12 and 14-16 of pregnancy, respectively. The results indicate that PPARs are involved in the production of PGF2α by porcine endometrium, and that the sensitivity of the endometrium to PPAR ligands depends on reproductive status of animals.

Topics: Analysis of Variance; Anilides; Animals; Benzamides; Culture Media; Dinoprost; DNA Primers; Endometrium; Estrous Cycle; Female; Indoles; Peroxisome Proliferator-Activated Receptors; Phenoxyacetates; Pregnancy; Prostaglandin D2; Pyridines; Pyrimidines; Radioimmunoassay; Real-Time Polymerase Chain Reaction; Reverse Transcriptase Polymerase Chain Reaction; Rosiglitazone; Swine; Thiazolidinediones

The main function of the human sebaceous gland is sebum excretion. Increased sebum levels combined with follicular hyperkeratinization are a prerequisite of acne vulgaris. As peroxisome proliferator-activated receptors (PPARs) are known to control lipid metabolism in several human tissues they have been considered to be involved in the pathogenesis of acne vulgaris.. To investigate the effect of activators of PPAR-α (WY14643), PPAR-γ (rosiglitazone) and PPAR-δ (L-165.041) on basal and staurosporine-induced apoptosis in the human sebocyte cell line SZ95 in vitro.. After defining the basal effects of PPAR activators on membrane integrity (lactate dehydrogenase release) and DNA synthesis (5-bromodeoxyuridine incorporation), apoptosis was determined by the release of histone-associated DNA fragments. The underlying signalling events were detected by Western blotting and the use of specific inhibitors against p44/42 and protein kinase B (PKB)/Akt.. PPAR activators of all three subsets offer antiapoptotic effects, with L-165.041 being the most potent. This compound induced the activation of PKB/Akt and p44/42, two kinases involved in antiapoptosis and proliferation, respectively. An inhibition of these kinases by specific inhibitors reversed the suppression of histone-associated DNA fragments by L-165.041, indicating that these signalling pathways participate in the observed antiapoptotic effect.. The present data suggest that activators of PPAR, in particular of the δ subset, might have beneficial effects on acne vulgaris by inhibiting the release of lipids in the context of sebocyte apoptosis.

Topics: Acne Vulgaris; Apoptosis; Blotting, Western; Bromodeoxyuridine; Cell Line; Enzyme Inhibitors; Humans; L-Lactate Dehydrogenase; Peroxisome Proliferator-Activated Receptors; Phenoxyacetates; PPAR alpha; PPAR delta; PPAR gamma; Pyrimidines; Rosiglitazone; Sebaceous Glands; Staurosporine; Thiazolidinediones

Insulin resistance is the failure of insulin to stimulate the transport of glucose into its target cells. A highly regulatable supply of glucose is important for cardiomyocytes to cope with situations of metabolic stress. We recently observed that isolated adult rat cardiomyocytes become insulin resistant in vitro. Insulin resistance is combated at the whole body level with agonists of the nuclear receptor complex peroxisome proliferator-activated receptor gamma (PPARgamma)/retinoid X receptor (RXR). We investigated the effects of PPARgamma/RXR agonists on the insulin-stimulated glucose transport and on insulin signaling in insulin-resistant adult rat cardiomyocytes. Treatment of cardiomyocytes with ciglitazone, a PPARgamma agonist, or 9-cis retinoic acid (RA), a RXR agonist, increased insulin- and metabolic stress-stimulated glucose transport, whereas agonists of PPARalpha or PPARbeta/delta had no effect. Stimulation of glucose transport in response to insulin requires the phosphorylation of the signaling intermediate Akt on the residues Thr308 and Ser473 and, downstream of Akt, AS160 on several Thr and Ser residues. Phosphorylation of Akt and AS160 in response to insulin was lower in insulin-resistant cardiomyocytes. However, treatment with 9-cis RA markedly increased phosphorylation of both proteins. Treatment with 9-cis RA also led to better preservation of microtubules in cultured cardiomyocytes. Disruption of microtubules in insulin-responsive cardiomyocytes abolished insulin-stimulated glucose transport and reduced phosphorylation of AS160 but not Akt. Metabolic stress-stimulated glucose transport also involved AS160 phosphorylation in a microtubule-dependent manner. Thus, the stimulation of glucose uptake in response to insulin or metabolic stress is dependent in cardiomyocytes on the presence of intact microtubules.

Topics: Alitretinoin; AMP-Activated Protein Kinase Kinases; Animals; Cells, Cultured; Cytoskeleton; Glucose; Glucose Transporter Type 4; Insulin; Insulin Resistance; Male; Microtubules; Myocytes, Cardiac; Phenoxyacetates; PPAR gamma; Protein Kinases; Pyrimidines; Rats; Rats, Sprague-Dawley; Retinoid X Receptors; Signal Transduction; Thiazolidinediones; Tretinoin

Inactivation of peroxisome proliferator-activated receptor (PPARs) isoforms alpha, beta/delta, and gamma mediate distinct facets of hypertrophic transformation of adult cardiac myocytes. PPARs are ligand-activated transcription factors that modulate the transcriptional regulation of fatty acid metabolism and the hypertrophic response in neonatal cardiac myocytes. The purpose of this study was to determine the role of PPAR isoforms in the morphologic and metabolic phenotype transformation of adult cardiac myocytes in culture, which, in medium containing 20% fetal calf serum, undergo hypertrophy-like cell growth associated with downregulation of regulatory proteins of fatty acid metabolism. Expression and DNA-binding activity of PPARalpha, PPARbeta/delta, and PPARgamma rapidly decreased after cell isolation and remained persistently reduced during the 14-day culture period. Cells progressively increased in size and developed both re-expression of atrial natriuretic factor and downregulation of regulatory proteins of fatty acid metabolism. Supplementation of the medium with fatty acid (oleate 0.25 mM/palmitate 0.25 mM) prevented inactivation of PPARs and downregulation of metabolic genes. Furthermore, cell size and markers of hypertrophy were markedly reduced. Selective activation of either PPARalpha or PPARbeta/delta completely restored expression of regulatory genes of fatty acid metabolism but did not influence cardiac myocyte size and markers of hypertrophy. Conversely, activation of PPARgamma prevented cardiomyocyte hypertrophy but had no effect on fatty acid metabolism. The results indicate that PPAR activity markedly influences hypertrophic transformation of adult rat cardiac myocytes. Inactivation of PPARalpha and PPARbeta/delta accounts for downregulation of the fatty acid oxidation pathway, whereas inactivation of PPARgamma enables development of hypertrophy.

Topics: Acyl-CoA Dehydrogenase; Animals; Atrial Natriuretic Factor; Cardiomegaly; Carnitine O-Palmitoyltransferase; CD36 Antigens; Cells, Cultured; Male; Myocytes, Cardiac; Oleic Acid; Palmitates; Phenoxyacetates; PPAR alpha; PPAR delta; PPAR gamma; PPAR-beta; Pyrimidines; Rats; RNA, Messenger; Thiazolidinediones

The Elovl3 gene, which putatively encodes for a protein involved in the elongation of saturated and monounsaturated fatty acids in the C20-C24 range, is expressed in murine liver, skin, and brown adipose tissue (BAT). In BAT, Elovl3 is dramatically upregulated during tissue activation in response to cold exposure, and functional data imply that ELOVL3 is a critical enzyme for lipid accumulation in brown adipocytes during the early phase of tissue recruitment. The activation of BAT is controlled by sympathetic nerve activity and norepinephrine release. By using primary cultures of brown adipocytes, we show here that the induced Elovl3 gene expression is synergistically regulated by norepinephrine and the peroxisome proliferator-activated receptor (PPAR) gamma ligand rosiglitazone. In addition, the potency of rosiglitazone to induce Elovl3 expression was several orders of magnitude higher than for the PPARalpha and PPARdelta ligands WY-14643 and L-165041, respectively. The maximal increase in mRNA level by norepinephrine and rosiglitazone is achieved by induced transcription as well as increased mRNA stability, and the whole process requires novel protein synthesis. We conclude that norepinehrine and PPARgamma, despite having different roles in brown adipocyte activation and differentiation, cooperate in expanding the intracellular lipid pool by synergistically stimulating Elovl3 expression.

Topics: Acetyltransferases; Adipocytes; Adipose Tissue, Brown; Animals; Cell Proliferation; Cycloheximide; Dactinomycin; Drug Synergism; Fatty Acid Elongases; Gene Expression Regulation; Male; Membrane Proteins; Mice; Norepinephrine; Peroxisome Proliferators; Phenoxyacetates; PPAR gamma; Protein Synthesis Inhibitors; Pyrimidines; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Rosiglitazone; Thiazolidinediones; Transcription, Genetic

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.

Topics: Acetates; Active Transport, Cell Nucleus; Binding Sites; Cell Nucleus; Cells, Cultured; Chemokine CCL2; Cytokines; Down-Regulation; Endothelium, Vascular; Gene Expression; Humans; Intercellular Adhesion Molecule-1; Monocytes; NF-kappa B; Peroxisome Proliferators; Phenols; Phenoxyacetates; Pyrimidines; Receptors, Cytoplasmic and Nuclear; Signal Transduction; Transcription Factors; Vascular Cell Adhesion Molecule-1