PPARgamma Protein Research Articles

Molecular docking of ferulic acid, bakuchiol and niazirin on peroxisome proliferator-activated receptor gamma (PPAR-γ) as anti-diabetic agents

Background: Diabetes mellitus remains one of the most dangerous illnesses worldwide. The PPAR-gamma protein plays a crucial role in lipid and carbohydrate metabolism, making it a key target for diabetes therapy. Research into plant-derived active compounds for diabetes treatment is increasingly important. Objective: This study aims to evaluate and analyze the interaction of ferulic acid, niazirin, and bakuchiol with the peroxisome proliferator-activated receptor gamma (PPAR-γ) protein using molecular docking. Methods: Molecular docking was employed to assess the interactions between ferulic acid, niazirin, bakuchiol, and the PPAR-γ protein (PDB ID: 2PRG). The analysis focused on binding free energy values, amino acid residue interactions, the number of hydrogen bonds, and bond distances, comparing these results to those of the native ligand and pioglitazone, a known anti-diabetic drug targeting PPAR-γ. Results: The binding free energies for the ferulic acid-PPAR-γ, bakuchiol-PPAR-γ, niazirin-PPAR-γ, native ligand-PPAR-γ, and pioglitazone-PPAR-γ complexes were -5.54 kcal/mol, -8.47 kcal/mol, -6.56 kcal/mol, -10.08 kcal/mol, and -9.94 kcal/mol, respectively. The amino acid residue similarity percentages with the native ligand were 18.18% for ferulic acid, 27.27% for bakuchiol, 18.18% for niazirin, and 81.82% for pioglitazone. The native ligand-2PRG and pioglitazone-2PRG complexes exhibited superior hydrogen bond numbers and shorter bond distances compared to the other compounds. Conclusion: Although bakuchiol showed the most promising interaction among the tested compounds, none surpassed the binding affinity and stability of the native ligand or pioglitazone. Further research is needed to optimize these compounds for potential anti-diabetic therapy.

Guggulsterone Selectively Modulates STAT-3, mTOR, and PPAR-Gamma Signaling in a Methylmercury-Exposed Experimental Neurotoxicity: Evidence from CSF, Blood Plasma, and Brain Samples.

Amyotrophic lateral sclerosis (ALS) is a paralytic disease that damages the brain and spinal cord motor neurons. Several clinical and preclinical studies have found that methylmercury (MeHg+) causes ALS. In ALS, MeHg+-induced neurotoxicity manifests as oligodendrocyte destruction; myelin basic protein (MBP) deficiency leads to axonal death. ALS development has been connected to an increase in signal transducer and activator of transcription-3 (STAT-3), a mammalian target of rapamycin (mTOR), and a decrease in peroxisome proliferator-activated receptor (PPAR)-gamma. Guggulsterone (GST), a plant-derived chemical produced from Commiphorawhighitii resin, has been found to protect against ALS by modulating these signaling pathways. Vitamin D3 (VitD3) deficiency has been related to oligodendrocyte precursor cells (OPC) damage, demyelination, and white matter deterioration, which results in motor neuron death. As a result, the primary goal of this work was to investigate the therapeutic potential of GST by altering STAT-3, mTOR, and PPAR-gamma levels in a MeHg+-exposed experimental model of ALS in adult rats. The GST30 and 60mg/kg oral treatments significantly improved the behavioral, motor, and cognitive dysfunctions and increased remyelination, as proven by the Luxol Fast Blue stain (LFB), and reduced neuroinflammation as measured by histological examinations. Furthermore, the co-administration of VitD3 exhibits moderate efficacy when administered in combination with GST60. Our results show that GST protects neurons by decreasing STAT-3 and mTOR levels while increasing PPAR-gamma protein levels in ALS rats.

Experimental and theoretical studies on 3-(4-chlorophenyl)-5-(4-ethoxyphenyl)-4,5-dihydropyrazole-1-carbonitrile: DFT quantum mechanical calculation, vibrational band analysis, prediction of activity spectra, and molecular docking

Synthesis, characterization (1H NMR, 13C NMR, FT-IR, elemental analysis), and DFT studies of the 3-(4-chlorophenyl)-5-(4-ethoxyphenyl)-4,5-dihydropyrazole-1-carbonitrile (6) were reported here. The optimized geometry of compound 6 in the ground state was obtained using DFT with the B3LYP/6-31++G(d,p). The experimental and theoretical vibrational frequencies of compound 6 were compared. The quantum chemical parameters were estimated theoretically. Moreover, the Prediction of Activity Spectra (PASS) analysis was performed. According to the PASS results, the molecular docking studies of the compound for rhinovirus B14, diabetic neuropathy treatment (PPAR-gamma protein), phobic disorders treatment (NSS Homolog protein), antidyskinetic (adenosine A2A protein), and picornavirus (enterovirus 71) protein were implemented.

In-silico anticancer potential of active constituents from “Glycyrrhiza uralensis” targeting PPAR gamma protein

The aim of the study is to anticipate the lead molecule from the phytochemical constituents of “Glycyrrhiza uralensis” which acts on PPAR γ receptor and causes cell proliferation and inhibits cell migration in cancer disease. PyRx virtual screening (Auto docking Vina) software and Schrodinger Maestro version 11.5 were used to screen the compounds anticancer activity. Python Molecular Viewer 1.5.6 (PMV 1.5.6) was used for semi flexible docking between the chemical compounds and PPAR γ protein receptor. Schrodinger Maestro version 11.5 was used to study the molecular dynamic simulation studies. Discovery Studio 2017 R2 Client software was used for visualizing the interactions respectively. Protein receptors and chemical constituents of G. Uralensis were retrieved from Protein Data Bank (PDB) and Pubchem databases respectively. A total of 136 chemical constituents of G. Uralensis were collected from various literature databases and 67 compounds were selected for virtual screening after ADME simulations along with standard drugs. Finally, 16 compounds were taken for molecular docking process from virtual screening. Through molecular docking studies, it was identified that 12 compounds had exhibited highest binding energy than the standard compounds. We also noticed that these 12 compounds had exhibited good pIC50 values also. Molecular dynamic simulation studies also support the data obtained from the molecular dynamic studies. Successful repositioning of the analyzed compounds on to the proposed binding site confirms the drug target ability of PPAR γ. Based on the free binding energy and pIC50 values, we propose 2 compounds (Uralenin, Glabrol) as small medicinal lead compounds for further development as potent anticancer drug candidate which act by inhibiting the PPAR γ protein receptor.

Hematopoietically-expressed homeobox protein HHEX regulates adipogenesis in preadipocytes

Obesity is a key health problem and is associated with a high risk of type 2 diabetes and other metabolic diseases. Increased weight as well as dysregulation of adipocyte homeostasis are the main drivers of obesity. Pathological adipogenesis plays a central role in obesity-related complications such as type 2 diabetes, hypertension and others. Thus, an understanding of the molecular mechanisms involved in physiological and pathogenic adipogenesis can help to develop new strategies to prevent or cure obesity and related diseases. Previously, genetic polymorphisms in the HHEX gene that encodes the homeobox transcription factor HEX (PRH) were found to be associated with type 2 diabetes and high body mass index at birth by GWAS in distinct human populations. To understand whether HHEX has a regulatory function in adipogenesis, we performed RNAi-mediated knockdown of Hhex in preadipocyte cell line 3T3-L1 in vitro, and studied changes in the efficacy of adipogenesis. We found that Hhex knockdown blocks adipogenesis in preadipocytes in a dose-dependent manner and leads to a significant decrease of PPAR-gamma protein – the main regulator of adipogenesis. We also propose that Hhex can play an important role in adipocyte differentiation by affecting the level of the PPAR-gamma protein. Our study supports the claim that Hhex plays an important role in adipocyte differentiation program and can contribute to fat tissue homeostasis.

The Role of M2 Macrophage in Primary Immune Thrombocytopenia

Background: Primary immune thrombocytopenia (ITP) is an acquired autoimmune hemorrhagic disorder, characterized by immune-mediated platelet destruction and impaired megakaryocyte maturation. Although impaired T cells have been implicated to participate in the pathogenesis of ITP, another immune cell signified as M2 macrophages has not been investigated properly in ITP patients. This study aimed to investigate the role of M2 macrophage subsets in primary immune thrombocytopenia (ITP). Methods: Peripheral blood mononuclear cells (PBMC) from newly diagnosed ITP patients and healthy controls (HC) were isolated. M2-like macrophages (CD68+CD163+) and M2 macrophages (CX3CR1+CD163+) were measured by flow cytometry. The correlation between CD68+CD163+ cells and CX3CR1+CD163+ cells was also analyzed. The CX3CR1+cells were sorted by magnetic bead, CD68+CD163+ in PBMC of ITP patients and healthy controls were then isolated, and the proportion of m2-like macrophages before and after the sorting was analyzed. The PPAR gamma and arg-1 levels of mRNAs and proteins of CX3CR1+ M2 macrophages were examined by Real-time PCR and Western Blot, respectively. Results: CX3CR1+CD163+M2 macrophages were positively correlated with CD68+ CD163+ M2-like macrophages in ITP patients (r = 0.54, p < 0.01). After magnetic bead separation, the proportion of CD68+CD163+ cells in CX3CR1+ cells was significantly increased (p = 0.02). Compared with HC, both the mRNA and protein levels of arg-1 of CX3CR1+ M2 macrophages were significantly increased in patients with ITP. The expression level of PPAR gamma protein was significantly increased in ITP than that of HC. However no statistical difference was detected at mRNA expression level, although it was numerically higher in ITP patients than in HC ( p = 0.19). Conclusion: The peripheral CX3CR1+ M2 macrophage exercises similar phenotypes and functions of M2 macrophage. The remarkably increased expression of arg-1 at both transcription and protein levels and PPAR gamma at protein level of CX3CR1+M2 macrophages in ITP patients suggests potential immunomodulatory functions of these macrophage subsets during ITP pathogenesis. However, no significant change at mRNA level of PPAR gamma indicating that the increased PPAR gamma protein level might be caused by other mechanisms, such as after transcription abnormalities, which warrants further investigation. Disclosures No relevant conflicts of interest to declare.

Efatutazone and T0901317 exert synergistically therapeutic effects in acquired gefitinib-resistant lung adenocarcinoma cells.

The development of acquired EGFR‐TKI therapeutic resistance is still a serious clinical problem in the management of lung adenocarcinoma. Peroxisome proliferator activated receptor gamma (PPAR γ) agonists may exhibit anti‐tumor activity by transactivating genes which are closely associated with cell proliferation, apoptosis, and differentiation. However, it remains not clear whether efatutazone has similar roles in lung adenocarcinoma cells of gefitinib resistant such as HCC827‐GR and PC9‐GR. It has been demonstrated by us that efatutazone prominently increased the mRNA and protein expression of PPAR γ, liver X receptor alpha (LXR α),as well as ATP binding cassette subfamily A member 1 (ABCA1). In the presence of GW9662 (a specific antagonist of PPAR γ) or GGPP (a specific antagonist of LXR α), efatutazone (40 μmol/L) restored the proliferation of both HCC827‐GR and PC9‐GR cells and obviously inhibited the increased protein and mRNA expression of PPAR‐gamma, LXR‐alpha, and ABCA1 induced by efatutazone. LXR α knockdown by siRNA (si‐LXR α) significantly promoted the HCC827‐GR and PC9‐GR cells proliferation, whereas incubation efatutazone with si‐LXR α restored the proliferation ability compared with the control group. In addition, combination of efatutazone and LXR α agonist T0901317 showed a synergistic therapeutic effect on lung adenocarcinoma cell proliferation and PPAR gamma, LXR A and ABCA1 protein expression. These results indicate that efatutazone could inhibit the cells proliferation of HCC827‐GR and PC9‐GR through PPAR γ/LXR α/ABCA1 pathway, and synergistic therapeutic effect is achieved when combined with T0901317.

The effect of PPARγ agonist on SGLT2 and glucagon expressions in alpha cells under hyperglycemia.

Although sodium glucose cotransporter 2 (SGLT2) inhibitors have many beneficial effects for type 2 diabetes, including decreased cardiovascular death, recent reports that they increased glucagon through SGLT2 inhibition raised some concern. Troglitazone, Peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, was reported to increase SGLT2 in renal proximal tubule cells, but its role on pancreatic alpha cells have not been reported. We investigated the effect of troglitazone on SGLT2 expression in alpha cells and subsequent glucagon regulation in hyperglycemia. An Alpha TC1-6 cell line was cultured in control (5 mM) or hyperglycemia (HG, 15mM) for 72h. We applied troglitazone with or without PPARγ antagonist (GW9662 10 μM). To investigate the involvement of PI3K/Akt pathway, we applied troglitazone with or without Wortmanin. We measured sodium glucose transporter 2 (SGLT2) and glucagon (GCG) mRNA and protein expression. PPAR gamma, PI3K and Akt protein were also measured. Exposure of alpha TC cells to HG for 72h increased glucagon mRNA and protein expression. HG decreased SGLT2 mRNA and protein expression. Troglitazone significantly reversed HG-induced reduction of SGLT2 expression and increase of glucagon secretion. PPARγ antagonist (GW9662 10μM) decreased the expression of SGLT2 and increased glucagon as HG did. Hyperglycemia increased PI3K and pAkt expression in alpha cells. Wortmanin (PI3K inhibitor, 1 μM) reversed HG-induced SGLT2 decrease and glucagon increase. Troglitazone treatment decreased PI3K and pAkt expression in HG. In conclusion, PPARγ agonist, troglitazone improved glucose transport SGLT2 dysfunction and subsequent glucagon dysregulation in alpha cell under hyperglycemia. Those effects were through the involvement of PI3K/pAkt signaling pathway. This study may add one more reason for the ideal combination of PPARγ agonist and SGLT2 inhibitor in clinical practice.

In silico Molecular Docking studies to investigate interactions of natural Camptothecin molecule with diabetic enzymes

The third leading cause of death in the world is Diabetes. Diabetes comes under a group of metabolic disorders in which the patients possess high blood glucose level. Camptothecin is an alkaloid compound with better antioxidant activity and in china it was used as traditional drugs to cure many diseases. The early researches on camptothecin revealed that it possess better anticancer and antitumor activity when compared with current available synthetic drugs. In silico drug designing and docking studies pave a way for better understanding of inhibitory activity of the compound over the respective target proteins. Molecular docking is one of the most powerful tools for predicting and analyzing the binding interactions between receptors and small molecules at the atomic level. In the current study, an in silico binding interaction of the compound camptothecin with three important diabetic targets like Glucokinase, insulin receptor and PPAR gamma were analyzed using Arguslab. ArgusLab software is used for molecular docking, to study the interactions between small compounds and its proteins. The compound camptothecin was first tested for its drug likeliness, bioactive properties and the results predicted that the compound passed the test for being an oral drug. The docking study revealed that camptothecin showed best binding affinity towards all the three proteins. Among the three proteins, PPAR gamma protein exhibited the lowest binding energy, followed by Glucokinase and insulin receptor with the binding energy of >-8.5 kcal/mol. Thus, Camptothecin compound could be considered as a better lead molecule in the development and discovery of new anti-diabetic drugs.

Effect of Intestinal Permeability and Gastrointestinal Segmental Transit Time Determined by Wireless Motility Capsule (SmartPill®)

Peroxisome proliferator-activated receptor gamma (PPAR gamma), a nuclear transcription factor, plays a critical role in the regulation of gene expression associated with inflammation and cancer. PPAR gamma is expressed in human gastric cancer as well as in colon cancer. Activation of PPAR gamma by ligand produces pro-apoptotic effect and ameliorate growing of cancer cells. Helicobacter pylori (H. pylori) is a main etiologic agent for gastric inflammation, and raises cell turnover in gastric epithelium. Longstanding infection with this organism is related with the development of non-cardiac gastric cancer. The aim of this study was to investigate the effect of H. pylori on the expression of PPAR gamma protein and mRNA in chronic gastritis.Gastric biopsy samples were taken from H. pylori infected (n=18) and non-infected (n=21) patients during endoscopic examination. PPAR gamma expressions were assessed by real time polymerase chain reaction and immunohistochemistry.PPAR gamma was localized to the nuclei of the foveolar epithelial cells in both infected and non-infected mucosa. PPAR gamma protein expression was higher in H. pylori infected patients than in non-infected patients (3.8+/-0.4 vs. 2.6+/-1.0, H. pylori infected and non-infected, respectively; p<0.05). However, PPAR gamma mRNA levels were not significantly different between the two groups (24+/-18 vs. 29+/-25, H. pylori infected and noninfected, respectively).PPAR gamma expression is increased in the gastric mucosa of H. pylori infected chronic gastritis, which suggests a certain role of PPAR gamma in the mucosal inflammatory reaction to H. pylori infection.

R-value comprehensive evaluation of effect of three methods for lung-kidney comprehensive evaluation study on R value of three methods for regulating and invigorating lung and kidney in regulating lung inflammation signaling pathways in COPD rats

Previous studies showed that three methods for regulating and invigorating lung and kidney (lung invigorating and spleen strengthening, lung invigorating and kidney tonifying, and Qi supplementing and kidney nourishing) could regulate inflammatory signaling pathways of chronic obstructive pulmonary disease (COPD) in rats, so as to alleviate inflammation. In the present study, R-value comprehensive evaluation method was used to evaluate the comprehensive effect of three methods for regulating and invigorating lung and kidney on inflammatory signaling pathways. Rats were randomly divided into control, model, lung invigorating and spleen strengthening, lung invigorating and kidney tonifying, Qi supplementing and kidney nourishing and aminophylline groups. The COPD rat models were established by cigarette smoking combined with bacterial infection, and orally administered with drugs between the 9th and 20th week. Afterwards, efforts were made to observe the long-term effects between the drug withdrawal and the 32rd week and detect indicators in two batches in the 20th week and 32th week. Specifically, (1) Linking JAK/STAT signaling pathway: JAK2 mRNA, and protein expressions of STAT-1, STAT-3, STAT-5, JAK-2; (2) NF-kappaB signaling pathway: Smad2 mRNA and protein expressions of I-kappaB, NF-kappaB, TGF-beta1; (3) PPARgamma and antioxidant signaling pathway: SOD, PGE mRNA, PPARgamma protein. According to the results, 5 indicators in JAK/STAT pathway, 4 indicators in NF-kappaB pathway, and 3 indicators in PPARgamma pathway were significantly rectified by three methods for regulating and invigorating lung and kidney in between the 20th week and 32nd week. Between the 20th and 32nd week, the recipes for rectifying JAK/STAT pathway with intensity from high to low were recipes for lung invigorating and spleen strengthening, Qi supplementing and kidney nourishing, lung invigorating and kidney tonifying, aminophylline, particularly those for lung invigorating and spleen strengthening; The recipes for rectifying NF-kappaB pathway with intensity from high to low were recipes for lung invigorating and spleen strengthening, lung invigorating and kidney tonifying, Qi supplementing and kidney nourishing and aminophylline, particularly the first three types of drugs. The recipes for rectifying PPARgamma and antioxidant signaling pathway with intensity from high to low were recipes for lung invigorating and kidney tonifying, Qi supplementing and kidney nourishing, lung invigorating and spleen strengthening and aminophylline. Therefore, three methods for regulating and invigorating lung and kidney showed better long-term effects in regulating COPD lung inflammation signaling pathways. Specifically, recipe for lung invigorating and spleen strengthening showed a better effect in JAK/STAT and NF-kappaB pathways, while recipe for lung invigorating and kidney tonifying and Qi supplementing and kidney nourishing showed better effects in PPARgamma and antioxidant signaling pathways. In conclusion, R-value comprehensive evaluation method can evaluate the comprehensive effect of medicines and define the ranking of multiple drugs and their main targets.

Effect of apigenin on protein expressions of PPARs in liver tissues of rats with nonalcoholic steatohepatitis

To investigate the effect of apigenin on the protein expression levels of peroxisome proliferator-activated receptors (PPARs) in liver tissues of rats with nonalcoholic steatohepatitis (NASH). The NASH rat model was established by feeding of a high-fat diet. Unmodeled rats served as the normal controls. The modeled rats were divided into a model control group, Essentiale treatment grouP(300 mg/kg/day),and three apigenin treatment groups for low-dose (15 mg/kg/day), moderate-dose (30 mg/kg/day) and high-dose (60 mg/kg/day). After 13 weeks of treatment,changes in insulin sensitivity from pre-treatment baseline were assessed by measuring the alanine aminotransferase (ALT), aspartate aminotransferase (AST),total cholesterol (TC),triglycerides (TG),low-density and high-density lipoprotein cholesterol (LDL-C and HDL-C),fasting blood glucose (FBG) and fasting insulin (FINS).The liver index and HOMA-IR were also calculated.Protein and gene expression of PPARα and PPARgamma in liver tissue were assessed by immunohistochemistry and RT-PCR.Statistical analysis was performed by the LSD test and Games-Howell test. The apigenin-treated groups showed a significantly greater change in insulin sensitivity than the untreated model group,with the most significant change occurring in the high-dose grouP(P less than 0.05).Compared with the untreated model group,the apigenin-treated groups showed lower levels of ALT (95.4+/-7.3),AST (183.7+/-14.3),TC (1.61+/-0.25),TG (1.23+/-0.21),LDL-C (1.86+/-0.14),FBG (5.29+/-1.45) and FINS (0.76+/-0.86),but a higher level of HDL-C (1.04+/-0.17); again,the high-dose group showed the greatest change (all P less than 0.05).Compared to the untreated model group,the apigenin-treated groups showed significantly lower liver index (3.75+/-0.25 vs.2.90+/-0.17) and HOMA-IR (1.34+/-0.06 vs.0.18+/-0.04),with the high-dose group showing the greatest change (both P less than 0.05). Compared to the untreated model group,the apigenin-treated groups showed higher levels of protein and mRNA of PPARα (18.27+/-4.05 and 0.63+/-0.02,respectively) and PPARgamma(8.48+/-5.05 and 0.39+/-0.02),with the high-dose group showing the greatest change (all P < 0.05). Apigenin can improve glucose tolerance,lipid metabolism and insulin resistance while decreasing blood levels of TC,TG,LDL-C,FBG,FINS and HOMA-IR,and increasing HDL-C in NASH,as shown in a high-fat diet induced rat model, and may have therapeutic potential.

DIABETES MELLITUS TIPO 2: QUAL O PAPEL DA INSULINA NA EXPRESSÃO DE NF-KappaB, PPARϒ E CD36?

No diabetes mellitus tipo 2 (DM2) e na síndrome de resistência à insulina, as complicações cardiovasculares resultam de um conjunto de processos aterogênicos envolvendo hiperglicemia crônica, excessiva glicação de proteínas (AGEs), ativação do fator nuclear kappa B (NKκB) associada com o aumento da expressão de citocinas inflamatórias e estresse oxidativo, observando-se ainda alteração de LDL e expressão do receptor de scavenger CD36. A contribuição da hiperinsulinemia nesta sequência não é completamente elucidada. Nesta revisão, relata-se como a insulina pode modular a expressão proteica de NFκB, PPAR gama (PPARγ) e CD36 em células da musculatura lisa vascular (CMLV) da aorta de ratos estimuladas pelos AGE.

Pravastatin activates the expression of farnesoid X receptor and liver X receptor alpha in Hep3B cells

Statins are suggested to preserve gallbladder function by suppressing pro-inflammatory cytokines and preventing cholesterol accumulation in gallbladder epithelial cells. They also affect cross-talk among the nuclear hormone receptors that regulate cholesterol-bile acid metabolism in the nuclei of hepatocytes. However, there is controversy over whether or how statins change the expression of peroxisome proliferator-activated receptor (PPAR)alpha, PPARgamma, liver X receptor alpha (LXRalpha), farnesoid X receptor (FXR), ABCG5, ABCG8, and 7alpha-hydroxylase (CYP7A1) which are directly involved in the cholesterol saturation index in bile. Human Hep3B cells were cultured on dishes. MTT assays were performed to determine the appropriate concentrations of reagents to be used. The protein expression of PPARalpha and PPARgamma was measured by Western blotting analysis, and the mRNA expression of LXRalpha, FXR, ABCG5, ABCG8 and CYP7A1 was estimated by RT-PCR. In cultured Hep3B cells, pravastatin activated PPARalpha and PPARgamma protein expression, induced stronger expression of PPARgamma than that of PPARalpha, increased LXRalpha mRNA expression, activated ABCG5 and ABCG8 mRNA expression mediated by FXR as well as LXRalpha, enhanced FXR mRNA expression, and increased CYP7A1 mRNA expression mediated by the PPARgamma and LXRalpha pathways, together or independently. Our data suggested that pravastatin prevents cholesterol gallstone diseases via the increase of FXR, LXRalpha and CYP7A1 in human hepatocytes.

Labisia pumilaUpregulates Peroxisome Proliferator-Activated Receptor Gamma Expression in Rat Adipose Tissues and 3T3-L1 Adipocytes

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-activated transcription factor that regulates lipid and glucose metabolism. We investigated the effects of Labisia pumila (LP) standardized water extract on PPARgamma transcriptional activity in adipocytes in vitro and in vivo. We used a rat model of dihydrotestosterone- (DHT-) induced polycystic ovary syndrome (PCOS), a condition characterized by insulin resistance. At 9 weeks of age, the PCOS rats were randomly subdivided into two groups: PCOS-LP (50 mg/kg/day of LP) and PCOS-control (1 mL of deionised water) for 4-5 weeks on the same schedule. Real-time RT-PCR was performed to determine the PPARgamma mRNA levels. LP upregulated PPARgamma mRNA level by 40% in the PCOS rats. Western blot analysis further demonstrated the increased PPARgamma protein levels in parallel with upregulation in mRNA. These observations were further proven by adipocytes culture. Differentiated 3T3-L1 adipocytes were treated with final concentration of 100 μg/mL LP and compared to untreated control and 10 μM of rosiglitazone (in type of thiazolidinediones). LP increased PPARgamma expressions at both mRNA and protein levels and enhanced the effect of glucose uptake in the insulin-resistant cells. The data suggest that LP may ameliorate insulin resistance in adipocytes via the upregulation of PPARgamma pathway.

The PPAR-gamma agonist pioglitazone protects cortical neurons from inflammatory mediators via improvement in peroxisomal function

BackgroundInflammation is known to play a pivotal role in mediating neuronal damage and axonal injury in a variety of neurodegenerative disorders. Among the range of inflammatory mediators, nitric oxide and hydrogen peroxide are potent neurotoxic agents. Recent evidence has suggested that oligodendrocyte peroxisomes may play an important role in protecting neurons from inflammatory damage.MethodsTo assess the influence of peroxisomal activation on nitric oxide mediated neurotoxicity, we investigated the effects of the peroxisomal proliferator activated receptor (PPAR) gamma agonist, pioglitazone in primary cortical neurons that were either exposed to a nitric oxide donor or co-cultured with activated microglia.ResultsPioglitazone protected neurons and axons against both nitric-oxide donor-induced and microglia-derived nitric oxide-induced toxicity. Moreover, cortical neurons treated with this compound showed a significant increase in the protein and gene expression of PPAR-gamma, which was associated with a concomitant increase in the enzymatic activity of catalase. In addition, the protection of neurons and axons against hydrogen peroxide-induced toxicity afforded by pioglitazone appeared to be dependent on catalase.ConclusionsCollectively, these observations provide evidence that modulation of PPAR-gamma activity and peroxisomal function by pioglitazone attenuates both NO and hydrogen peroxide-mediated neuronal and axonal damage suggesting a new therapeutic approach to protect against neurodegenerative changes associated with neuroinflammation.

Efficacy of a Non-Hypercalcemic Vitamin-D2 Derived Anti-Cancer Agent (MT19c) and Inhibition of Fatty Acid Synthesis in an Ovarian Cancer Xenograft Model

BackgroundNumerous vitamin-D analogs exhibited poor response rates, high systemic toxicities and hypercalcemia in human trials to treat cancer. We identified the first non-hypercalcemic anti-cancer vitamin D analog MT19c by altering the A-ring of ergocalciferol. This study describes the therapeutic efficacy and mechanism of action of MT19c in both in vitro and in vivo models.Methodology/Principal FindingAntitumor efficacy of MT19c was evaluated in ovarian cancer cell (SKOV-3) xenografts in nude mice and a syngenic rat ovarian cancer model. Serum calcium levels of MT19c or calcitriol treated animals were measured. In-silico molecular docking simulation and a cell based VDR reporter assay revealed MT19c–VDR interaction. Genomewide mRNA analysis of MT19c treated tumors identified drug targets which were verified by immunoblotting and microscopy. Quantification of cellular malonyl CoA was carried out by HPLC-MS. A binding study with PPAR-Y receptor was performed. MT19c reduced ovarian cancer growth in xenograft and syngeneic animal models without causing hypercalcemia or acute toxicity. MT19c is a weak vitamin-D receptor (VDR) antagonist that disrupted the interaction between VDR and coactivator SRC2-3. Genome-wide mRNA analysis and western blot and microscopy of MT19c treated xenograft tumors showed inhibition of fatty acid synthase (FASN) activity. MT19c reduced cellular levels of malonyl CoA in SKOV-3 cells and inhibited EGFR/phosphoinositol-3kinase (PI-3K) activity independently of PPAR-gamma protein.SignificanceAntitumor effects of non-hypercalcemic agent MT19c provide a new approach to the design of vitamin-D based anticancer molecules and a rationale for developing MT19c as a therapeutic agent for malignant ovarian tumors by targeting oncogenic de novo lipogenesis.

Ascorbic acid‐induced reduction in adiponectin is not improved by alpha tocopherol and is accompanied by a small reduction in protein levels of Peroxisome Proliferator‐ Activated Receptor Gamma in 3T3‐L1 adipocytes

Adipocytes play a role in metabolism and regulation of homeostasis through the release of cytokines such as adiponectin. Adiponectin is an anti‐inflammatory adipokine and has been shown to improve insulin sensitivity and enhance beta‐oxidation of fatty acids. A reduction in adiponectin has been associated with increased inflammation, metabolic syndrome and chronic diseases. Since oxidative stress has been known to regulate metabolic disease, we previously investigated the role of ascorbic acid and found that it abolished adiponectin expression in adipocytes. We hypothesized that treatment with ascorbic acid may cause a reduction in PPARgamma protein levels and that alpha tocopherol may mitigate the effect of ascorbic acid on adiponectin synthesis. We used 3T3‐L1 cells to monitor adiponectin protein levels. Differentiated 3T3‐L1 (Day 8), cells were treated with ascorbic acid, with and without alpha tocopherol. We found that the reduction of adiponectin in cell lysates was not overcome with the addition of alpha tocopherol. Further, we also observed a small reduction in PPARgamma in adipocytes treated with ascorbic acid. These results suggest that adipocyte metabolism may be influenced by dietary antioxidants. This research was funded by Florida International University.

Enhanced PPAR-γ Expression May Correlate With the Development of Barrett's Esophagus and Esophageal Adenocarcinoma

PPAR-gamma is known to have a growth-suppressive effect in different cancers. In this study, we investigated the role of PPAR-gamma in the development of Barrett's esophagus (BE) and esophageal adenocarcinoma (EA). We used immunohistochemistry and real-time PCR to analyze differences in PPAR-gamma protein and mRNA expression levels in samples of normal esophageal squamous epithelium (n = 75), BE (n = 50), and EA (n = 25). Immunoreactivity with antibodies against PPAR-gamma was confined to the nuclei of goblet cells and surface glandular epithelium in BE samples. We found significantly lower levels of expression of PPAR-gamma protein (p < 0.01) in normal esophageal squamous epithelium when compared to BE and EA samples. PPAR-gamma protein levels showed an increasing trend from normal esophageal squamous epithelium < BE samples < EA samples (p < 0.01). PPAR-gamma mRNA expression levels in BE and EA samples were 5.9130-fold (p < 0.01) and 2.0314-fold (p < 0.01) higher than that of normal esophageal squamous epithelium, respectively. There was a trend towards increased expression of PPAR-gamma with decreasing levels of differentiation. Increased PPAR-gamma expression may play an important role in the development and progression from normal cells to BE and EA.

Relationship among superoxide-related enzyme, PPARs, and endothelium-dependent relaxation in murine aortas previously organ-cultured in high-glucose conditions

The aim of the present study was to investigate the relationship among superoxide anion, peroxisome proliferator-activated receptors (PPARs), and endothelium-dependent relaxation in murine aortas organ-cultured in a high-glucose condition. Aortas organ-cultured with a high concentration of glucose (40 mmol/L, 20 h; HG group) exhibited the following characteristics (versus aortas cultured in serum-free medium): (i) significantly weaker relaxation to acetylcholine, but unchanged relaxation to SNP and unchanged contractions to norepinephrine and isotonic K+, (ii) significantly greater superoxide generation (indicated by the amount of nitroblue tetrazolium reduced, (iii) significantly higher protein expression levels of gp91phox, NAD(P)H oxidase subunits, and endothelial NO synthase, (iv) significantly lower protein expression level of Mn-superoxide dismutase (SOD), and (v) markedly greater reduction in the protein expression of PPARgamma than in that of PPARalpha. The HG-induced impairment of endothelium-dependent relaxation was prevented by cotreatment with tempol (a SOD mimetic). These results suggest that in the mouse aorta, exposure to high glucose levels may lead to an excessive generation of superoxide via increased gp91phox and decreased Mn-SOD protein expression and that this may in turn trigger an impairment of endothelium-dependent relaxation. Moreover, such protein changes in gp91phox and Mn-SOD may be secondary to a decreased expression of PPARgamma protein.