Project description:Previous studies indicate that peroxisome proliferator-activated receptor-gamma (PPAR-g) agonists suppress autoimmune responses and renal inflammation in murine lupus. However, the mechanisms implicated in this process remain unclear. We tested the effect of the PPAR-g agonist pioglitazone in human lupus and control PBMCs with regards to gene regulation and various functional assays. We used microarrays to analyze the effect of Pioglitazone on peripheral blood cells (PBMCs) from healthy and lupus patients.
Project description:Previous studies indicate that peroxisome proliferator-activated receptor-gamma (PPAR-g) agonists suppress autoimmune responses and renal inflammation in murine lupus. However, the mechanisms implicated in this process remain unclear. We tested the effect of the PPAR-g agonist pioglitazone in human lupus and control PBMCs with regards to gene regulation and various functional assays. We used microarrays to analyze the effect of Pioglitazone on peripheral blood cells (PBMCs) from healthy and lupus patients. Human PBMCs were isolated; RNA from healthy and lupus PBMCs was extracted and processed for hybridization on Affymetrix microarrays. Samples are paired as follows: 1-2, 3-4, 5-6, 7-8, 9-10, 11-12, 13-14, 15-16, 19-20.
Project description:PPARδ is emerging as a key metabolic regulator with pleiotropic actions on various tissues including fat, skeletal muscle and liver. The aim of our study was to assess the effect of either the well-validated PPARδ agonist GW501516, or a novel PPARδ agonist KD3010 in mouse models of liver fibrosis. KD3010, but not GW501516, treated mice had markedly less liver injury induced by carbon tetrachloride (CCl4) injections. Deposition of extracellular matrix proteins was lower in the KD3010 group as compared to the vehicle or GW501516 treated group. Interestingly, profibrogenic CTGF was significantly induced by GW501516, but not KD3010, following CCl4 treatment. The hepatoprotective and antifibrotic effect of KD3010 was confirmed in a model of cholestasis-induced liver injury and fibrosis using bile duct ligation for three weeks. Hepatocytes were identified as targets for PPARδ agonist, and primary hepatocytes treated with KD3010 showed decreased serum starvation or CCl4-induced cell death, while GW501516 treated hepatocytes were not protected. KD3010 treatment of hepatocytes decreased reactive oxygen species (ROS) production after CCl4 exposure. In conclusion, our data demonstrate that a novel PPARδ agonist has hepatoprotective and antifibrotic effects in animal models of liver fibrosis. Given the oral availability and the favorable pharmacologic profile of KD3010, ligand activation of PPARδ represents an attractive and promising target for patients with chronic liver diseases. Total RNA was extracted from primary mouse hepatocytes treated with DMSO or PPARd agonists (KD3010, GW1516)
Project description:PPARδ is emerging as a key metabolic regulator with pleiotropic actions on various tissues including fat, skeletal muscle and liver. The aim of our study was to assess the effect of either the well-validated PPARδ agonist GW501516, or a novel PPARδ agonist KD3010 in mouse models of liver fibrosis. KD3010, but not GW501516, treated mice had markedly less liver injury induced by carbon tetrachloride (CCl4) injections. Deposition of extracellular matrix proteins was lower in the KD3010 group as compared to the vehicle or GW501516 treated group. Interestingly, profibrogenic CTGF was significantly induced by GW501516, but not KD3010, following CCl4 treatment. The hepatoprotective and antifibrotic effect of KD3010 was confirmed in a model of cholestasis-induced liver injury and fibrosis using bile duct ligation for three weeks. Hepatocytes were identified as targets for PPARδ agonist, and primary hepatocytes treated with KD3010 showed decreased serum starvation or CCl4-induced cell death, while GW501516 treated hepatocytes were not protected. KD3010 treatment of hepatocytes decreased reactive oxygen species (ROS) production after CCl4 exposure. In conclusion, our data demonstrate that a novel PPARδ agonist has hepatoprotective and antifibrotic effects in animal models of liver fibrosis. Given the oral availability and the favorable pharmacologic profile of KD3010, ligand activation of PPARδ represents an attractive and promising target for patients with chronic liver diseases.
Project description:Our aim was to investigate if the peroxisome proliferator-activated receptor (PPAR)-gamma agonist pioglitazone modulates inflammation through PPARalpha mechanisms.The thiazolidinediones (TZDs) pioglitazone and rosiglitazone are insulin-sensitizing PPARgamma agonists used to treat type 2 diabetes (T2DM). Despite evidence for TZDs limiting inflammation and atherosclerosis, questions exist regarding differential responses to TZDs. In a double-blinded, placebo-controlled 16-week trial among recently diagnosed T2DM subjects (n = 34), pioglitazone-treated subjects manifested lower triglycerides and lacked the increase in soluble vascular cell adhesion molecules (sVCAM)-1 evident in the placebo group. Previously we reported PPARalpha but not PPARgamma agonists could repress VCAM-1 expression. Since both triglyceride-lowering and VCAM-1 repression characterize PPARalpha activation, we studied pioglitazone's effects via PPARalpha.Pioglitazone effects on known PPARalpha responses--ligand binding domain activation and PPARalpha target gene expression--were tested in vitro and in vivo, including in wild-type and PPARalpha-deficient cells and mice, and compared with the effects of other PPARgamma (rosiglitazone) and PPARalpha (WY14643) agonists.Pioglitazone repressed endothelial TNFalpha-induced VCAM-1 messenger ribonucleic acid expression and promoter activity, and induced hepatic IkappaBalpha in a manner dependent on both pioglitazone exposure and PPARalpha expression. Pioglitazone also activated the PPARalpha ligand binding domain and induced PPARalpha target gene expression, with in vitro effects that were most pronounced in endothelial cells. In vivo, pioglitazone administration modulated sVCAM-1 levels and IkappaBalpha expression in wild-type but not PPARalpha-deficient mice.Pioglitazone regulates inflammatory target genes in hepatic (IkappaBalpha) and endothelial (VCAM-1) settings in a PPARalpha-dependent manner. These data offer novel mechanisms that may underlie distinct TZD responses.
Project description:Peroxisome proliferator‑activated receptors (PPARs) have been suggested as the master regulators of adipose tissue formation, however their role in regulating brown fat functionality has not been resolved. To address this question, we generated inducible brown fat specific mouse models for PPARa, b/d and g, respectively. Interestingly, we found that both PPARa and b/d are dispensable for brown fat function. In contrast, we could show that ablation of PPARg in vitro as well in vivo led to a reduced thermogenic capacity accompanied by a loss of inducibility by β-adrenergic signaling, as well as a shift from oxidative fatty acid metabolism to glucose utilization. We identified glycerol kinase (Gyk) as a partial mediator of PPARgfunction, and could show that Gyk expression correlates with brown fat thermogenic capacity in human brown fat biopsies. Thus, Gyk might constitute the link between PPARg mediated regulation of brown fat function and activation by β-adrenergic signaling.
Project description:Lipid metabolism is essential in maintaining energy homeostasis in multicellular organisms. In vertebrates, a group of nuclear receptor transcription factors named peroxisome proliferator-activated receptors (PPARs, NR1C) regulate the expression of many genes involved in these processes. We have recently cloned the four Ppars in Atlantic cod (Gadus morhua), including Ppara1 and Ppara2, Pparb/d, and Pparg, and studied their tissue specific transcription and ligand activation characteristics. However, the downstream regulative role of Ppars in cod lipid metabolism is not well understood or described. In this study, activation of Atlantic cod Ppar by the fibrate drug WY-14,643 (pirinixic acid) and the performance enhancing drug GW501516 (Cardarine) were first studied using ligand-binding luciferase reporter assays in vitro. Based on the agonist activities found in vitro, juvenile Atlantic cod was injected twice over four days with WY-14,643 and GW501516 in vivo, and sampled seven days after the last injection. Using multiple omics methods, including RNA sequencing, quantitative proteomics, and lipidomics, liver and plasma samples from male cod were analyzed. The resulting multi-omics dataset provides novel insights into the systemic regulation of lipid metabolism in Atlantic cod.
Project description:Thiazolidinediones increase tissue insulin sensitivity and are protective against worsening of nephropathy and hypertension in diabetes. Mechanisms underlying protection at the renal level likely involve a variety of unknown changes in gene expression. We examined kidney gene expression in obese and lean Zucker rats in response to rosiglitazone (Avandia®), a peroxisome proliferator activated receptor (gamma-subtype) agonist. Lean and obese Zucker rats were treated with either control chow or chow with added rosiglitazone (3 mg/kg�bw) for 12 weeks (n = 3/group). Total kidney mRNA expression was evaluated using the Affymetrix Rat Genome 230 2.0 GeneChip. 903 probe sets were significantly (P < 0.05) altered with at least 1.5-fold changes between groups. In untreated obese rats, 300 probe sets were increased and 244 decreased, relative to lean. Increased genes included the β-subunit of the epithelial sodium channel (ENaC), the thiazide-sensitive Na-Cl cotransporter, and aquaporin 3. Decreased genes included angiotensin converting enzyme, type 1 (ACE1). FatiGO analysis showed that the highest number of altered genes between lean and obese belonged to the categories: ion binding, hydrolase activity, and protein binding. RGZ increased expression of uncoupling protein 1 (UCP1), CD36, and fatty acid binding protein 4 (FAbp4) in both lean and obese rats. In obese rats, 33 genes were normalized by RGZ (no longer different from lean) including ACE1, fatty acid synthase (Fasn), and stearoyl-coenzyme A desaturase 2 (Scd2). Ingenuity Pathways System analysis of genes upregulated by RGZ in obese rats revealed two major nodes affected: PPAR-gamma and tumor necrosis factor alpha (TNF-alpha). Experiment Overall Design: Twelve male Zucker rats (6 Lean and 6 Obese) were used in the study. Three rats from each body type were fed either with control diet (ground chow diet) or control diet with rosiglitazone (3 mg/kg body weight). The rats were weighed weekly and fed diets and recieved water ad libitum for 12 weeks.