Project description:To explore the molecular pathways underlying thiazolidinediones effects on pancreatic islets in conditions mimicking normo- and hyperglycemia, apoptosis rate and transcriptional response to Pioglitazone at both physiological and supraphysiological glucose concentrations were evaluated.
Project description:Aims: To compare the molecular and biologic signatures of a balanced dual peroxisome proliferator-activated receptor-α/γ (PPAR-α/γ) agonist, aleglitazar, with tesaglitazar (a dual PPAR-α/γ agonist) or combination of pioglitazone (PPAR-γ agonist)/fenofibric acid (PPAR-α agonist) in human hepatocytes. Methods and Results: Gene expression microarray profiles were obtained from primary human hepatocytes treated with EC50-aligned low, medium, and high concentrations of the three treatments. A systems-biology approach, Causal Network Modeling, was used to model the data to infer upstream molecular mechanisms that may explain the observed changes in gene expression. Aleglitazar, tesaglitazar and pioglitazone/fenofibric acid, each induced unique transcriptional signatures, despite comparable core PPAR signaling. Although all treatments inferred qualitatively similar PPAR-α signaling, aleglitazar was inferred to have greater effects on high- and low-density lipoprotein cholesterol levels than tesaglitazar and pioglitazone/fenofibric acid, due to greater number of gene expression changes in pathways related to HDL and LDL metabolism. Distinct transcriptional and biologic signatures were also inferred for stress responses, which appeared to be less affected by aleglitazar than the comparators. In particular, pioglitazone/fenofibric acid was inferred to increase NFE2L2 activity, a key component of the stress response pathway, while aleglitazar had no significant effect. All treatments were inferred to decrease proliferative signaling. Conclusions: Aleglitazar induces transcriptional signatures related to lipid parameters and stress responses that are unique from other dual PPAR-α/γ treatments. This may underlie observed favorable changes in lipid profiles in animal and clinical studies with aleglitazar and suggests a differentiated gene profile compared with other dual PPAR-α/γ agonist treatments.
Project description:To explore the molecular pathways underlying thiazolidinediones effects on pancreatic islets in conditions mimicking normo- and hyperglycemia, apoptosis rate and transcriptional response to Pioglitazone at both physiological and supraphysiological glucose concentrations were evaluated. Adult rat islets were cultured at physiological (5.6 mM) and supraphysiological (23 mM) glucose concentrations in presence of 10 mM Pioglitazone or vehicle. RNA expression profiling was evaluated with the PancChip 13k cDNA microarray after 24-h, and expression results for some selected genes were validated by qRT-PCR.
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:To assess whether changes in islet gene expression contribute to differences in phenotypes in response to high fat diet or tretament with pioglitazone, Agilent Whole Mouse Genome Oligo Microarrays were performed on RNA isolated from islets of 4 mice per each treatment group for discovery analysis of gene expression. Male 8 week-old BL6 and BLKS mice were fed normal chow (18% kcal from fat), HFD (42% kcal from fat), or HFD supplemented with the PPAR-γ agonist pioglitazone (PIO) (140 mg PIO/kg diet) for 16 weeks.
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:We evaluated the effects of pioglitazone in mouse organ of Corti (OC) explants to characterize its influence on signaling pathways involved in auditory hair cell damage. Organ of Corti explants were cultured with pioglitazone, gentamicin, or a combination of both agents. Pioglitazone treatment resulted in a significant repression of interferon (IFN)-alpha and -gamma pathways and downstream cytokines, as assessed by RNA sequencing and quantitative PCR gene expression assays. More detailed investigation at the single gene and protein level showed that pioglitazone mediated its anti-inflammatory effects through alterations of the Toll-like receptor (TLR) and STAT pathways. Together, these results indicate that pioglitazone significantly represses IFN and TLR in the cochlea, dampening the activity of gentamicin-induced pathways. These data support our previous results demonstrating significant protection of auditory hair cells in organ of Corti explants exposed to pioglitazone and other PPAR-targeted agents.
Project description:Obesity is a major risk factor for the development of insulin resistance and type II diabetes. The nuclear receptors PPAR delta and PPAR gamma play a central role in regulating metabolism in adipose tissue, as well as being targets for the treatment of insulin resistance. The metabolic effects of PPAR delta and PPAR gamma activation have been examined both in vivo in white adipose tissue from ob/ob mice and in vitro in cultured 3T3-L1 adipocytes using a combined 1H NMR spectroscopy and mass spectrometry metabolomic methodology to understand the contrasting roles of these receptors. These steady state measurements were supplemented with 13C-stable isotope substrate labeling to assess fluxes, respirometry and transcriptomic microarray analysis. The metabolic effects of the two receptors were readily distinguished, with PPAR gamma ?activation characterised by increased fat storage and fat synthesis/elongation, while activation of PPAR delta caused increased fatty acid beta-oxidation, TCA cycle rate and oxidation of extracellular branch chain amino acids. Stimulated glycolysis and increased desaturation of fatty acids were the only common pathways. PPAR delta has a role as an anti-obesity target as well as an anti-diabetic. Total RNA obtained from cultured 3T3-L1 cells treated for 48 hours with either DMSO control, GW610742 PPARd agonist or GW347845 PPARg agonist and compared.
Project description:Neonates born pre-term or/and at low weight often suffer from defective lung function where PPAR-gamma cascades play an important role. Curcumin is a PPAR gamma agonist
Project description:Neonates born pre-term or/and at low weight often suffer from defective lung function where PPAR-gamma cascades play an important role. Curcumin is a PPAR gamma agonist at postnatal day 11
