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Structural basis for PPAR partial or full activation revealed by a novel ligand binding mode. Sci Rep 2016; 6:34792. [PMID: 27708429 PMCID: PMC5052532 DOI: 10.1038/srep34792] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/20/2016] [Indexed: 12/14/2022] Open
Abstract
The peroxisome proliferator-activated receptors (PPARs) are nuclear receptors involved in the regulation of the metabolic homeostasis and therefore represent valuable therapeutic targets for the treatment of metabolic diseases. The development of more balanced drugs interacting with PPARs, devoid of the side-effects showed by the currently marketed PPARγ full agonists, is considered the major challenge for the pharmaceutical companies. Here we present a structure-based virtual screening approach that let us identify a novel PPAR pan-agonist with a very attractive activity profile and its crystal structure in the complex with PPARα and PPARγ, respectively. In PPARα this ligand occupies a new pocket whose filling is allowed by the ligand-induced switching of the F273 side chain from a closed to an open conformation. The comparison between this pocket and the corresponding cavity in PPARγ provides a rationale for the different activation of the ligand towards PPARα and PPARγ, suggesting a novel basis for ligand design.
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Wang S, Dougherty EJ, Danner RL. PPARγ signaling and emerging opportunities for improved therapeutics. Pharmacol Res 2016; 111:76-85. [PMID: 27268145 DOI: 10.1016/j.phrs.2016.02.028] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 02/29/2016] [Indexed: 01/23/2023]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated nuclear receptor that regulates glucose and lipid metabolism, endothelial function and inflammation. Rosiglitazone (RGZ) and other thiazolidinedione (TZD) synthetic ligands of PPARγ are insulin sensitizers that have been used for the treatment of type 2 diabetes. However, undesirable side effects including weight gain, fluid retention, bone loss, congestive heart failure, and a possible increased risk of myocardial infarction and bladder cancer, have limited the use of TZDs. Therefore, there is a need to better understand PPARγ signaling and to develop safer and more effective PPARγ-directed therapeutics. In addition to PPARγ itself, many PPARγ ligands including TZDs bind to and activate G protein-coupled receptor 40 (GPR40), also known as free fatty acid receptor 1. GPR40 signaling activates stress kinase pathways that ultimately regulate downstream PPARγ responses. Recent studies in human endothelial cells have demonstrated that RGZ activation of GPR40 is essential to the optimal propagation of PPARγ genomic signaling. RGZ/GPR40/p38 MAPK signaling induces and activates PPARγ co-activator-1α, and recruits E1A binding protein p300 to the promoters of target genes, markedly enhancing PPARγ-dependent transcription. Therefore in endothelium, GPR40 and PPARγ function as an integrated signaling pathway. However, GPR40 can also activate ERK1/2, a proinflammatory kinase that directly phosphorylates and inactivates PPARγ. Thus the role of GPR40 in PPARγ signaling may have important implications for drug development. Ligands that strongly activate PPARγ, but do not bind to or activate GPR40 may be safer than currently approved PPARγ agonists. Alternatively, biased GPR40 agonists might be sought that activate both p38 MAPK and PPARγ, but not ERK1/2, avoiding its harmful effects on PPARγ signaling, insulin resistance and inflammation. Such next generation drugs might be useful in treating not only type 2 diabetes, but also diverse chronic and acute forms of vascular inflammation such as atherosclerosis and septic shock.
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Affiliation(s)
- Shuibang Wang
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Edward J Dougherty
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert L Danner
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
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Wellhauser L, Chalmers JA, Belsham DD. Nitric Oxide Exerts Basal and Insulin-Dependent Anorexigenic Actions in POMC Hypothalamic Neurons. Mol Endocrinol 2016; 30:402-16. [PMID: 26930171 DOI: 10.1210/me.2015-1275] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The arcuate nucleus of the hypothalamus represents a key center for the control of appetite and feeding through the regulation of 2 key neuronal populations, notably agouti-related peptide/neuropeptide Y and proopimelanocortin (POMC)/cocaine- and amphetamine-regulated transcript neurons. Altered regulation of these neuronal networks, in particular the dysfunction of POMC neurons upon high-fat consumption, is a major pathogenic mechanism involved in the development of obesity and type 2 diabetes mellitus. Efforts are underway to preserve the integrity or enhance the functionality of POMC neurons in order to prevent or treat these metabolic diseases. Here, we report for the first time that the nitric oxide (NO(-)) donor, sodium nitroprusside (SNP) mediates anorexigenic actions in both hypothalamic tissue and hypothalamic-derived cell models by mediating the up-regulation of POMC levels. SNP increased POMC mRNA in a dose-dependent manner and enhanced α-melanocortin-secreting hormone production and secretion in mHypoA-POMC/GFP-2 cells. SNP also enhanced insulin-driven POMC expression likely by inhibiting the deacetylase activity of sirtuin 1. Furthermore, SNP enhanced insulin-dependent POMC expression, likely by reducing the transcriptional repression of Foxo1 on the POMC gene. Prolonged SNP exposure prevented the development of insulin resistance. Taken together, the NO(-) donor SNP enhances the anorexigenic potential of POMC neurons by promoting its transcriptional expression independent and in cooperation with insulin. Thus, increasing cellular NO(-) levels represents a hormone-independent method of promoting anorexigenic output from the existing POMC neuronal populations and may be advantageous in the fight against these prevalent disorders.
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Affiliation(s)
- Leigh Wellhauser
- Department of Physiology (L.W., J.A.C., D.D.B.), University of Toronto, Toronto, Ontario, Canada M5G 1A8; and Departments of Obstetrics, Gynaecology, and Medicine (D.D.B.), University of Toronto and Division of Cellular and Molecular Biology, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada M5S 1A8
| | - Jennifer A Chalmers
- Department of Physiology (L.W., J.A.C., D.D.B.), University of Toronto, Toronto, Ontario, Canada M5G 1A8; and Departments of Obstetrics, Gynaecology, and Medicine (D.D.B.), University of Toronto and Division of Cellular and Molecular Biology, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada M5S 1A8
| | - Denise D Belsham
- Department of Physiology (L.W., J.A.C., D.D.B.), University of Toronto, Toronto, Ontario, Canada M5G 1A8; and Departments of Obstetrics, Gynaecology, and Medicine (D.D.B.), University of Toronto and Division of Cellular and Molecular Biology, Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada M5S 1A8
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Jia HJ, Zhang PJ, Liu YL, Jiang CG, Zhu X, Tian YP. Relationship of serum polyunsaturated fatty acids with cytokines in colorectal cancer. World J Gastroenterol 2016; 22:2524-2532. [PMID: 26937140 PMCID: PMC4768198 DOI: 10.3748/wjg.v22.i8.2524] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 02/03/2016] [Accepted: 02/19/2016] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the relationship of serum levels of polyunsaturated fatty acid (PUFA) with kinds of cytokines in colorectal cancer (CRC).
METHODS: Serum samples of 100 CRC patients were collected. The concentration of total n-3 PUFA which included C18:3 n-3, C20:5 n-3, C22:5 n-3, C22:6 n-3 and the total n-6 PUFA included C18:2 n-6, C18:3 n-6, C20:3 n-6, C20:4 n-6, and C22:5 n-6 were detected on GC-2010 Plus Gas Chromatograph with a OmegawaxTM 250 column. Cytokines were detected by MagPlexTM-C microspheres. P values for the trend were estimated by creating a continuous variable using the median value within quartiles.
RESULTS: Interleukin-6 (IL-6) showed significantly positive association with the C20:4 n-6 (P for trend = 0.004). Interferon gamma (IFN-γ) showed significant positive association with the C22:5 n-3 (P for trend = 0.035). IL-8 and matrix metalloproteinase-9 (MMP-9) showed significant inverse association with the C22:6 n-3 (P for trend = 0.049, and 0.021). MMP-2 showed significant inverse association with the C20:5 n-3 (P for trend = 0.008). MMP-7 showed significantly positive association with the ratio of n-6 PUFA and n-3 PUFA (P for trend = 0.008). MMP-7 also showed significantly inverse association with the ratio of C20:4 n-6 and (n-6 PUFA + n-3 PUFA) (P for trend = 0.024). IL-10 (P for trend = 0.023) and IL-6 (P for trend = 0.036) showed significantly positive association with the ratio of C20:4 n-6 and C20:5 n-3.
CONCLUSION: Our data suggested that serum levels of PUFA is related to the inflammation of CRC, and also play different role in regulation of immune response.
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Palomer X, Barroso E, Zarei M, Botteri G, Vázquez-Carrera M. PPARβ/δ and lipid metabolism in the heart. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:1569-78. [PMID: 26825692 DOI: 10.1016/j.bbalip.2016.01.019] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/23/2015] [Accepted: 01/22/2016] [Indexed: 12/13/2022]
Abstract
Cardiac lipid metabolism is the focus of attention due to its involvement in the development of cardiac disorders. Both a reduction and an increase in fatty acid utilization make the heart more prone to the development of lipotoxic cardiac dysfunction. The ligand-activated transcription factor peroxisome proliferator-activated receptor (PPAR)β/δ modulates different aspects of cardiac fatty acid metabolism, and targeting this nuclear receptor can improve heart diseases caused by altered fatty acid metabolism. In addition, PPARβ/δ regulates glucose metabolism, the cardiac levels of endogenous antioxidants, mitochondrial biogenesis, cardiomyocyte apoptosis, the insulin signaling pathway and lipid-induced myocardial inflammatory responses. As a result, PPARβ/δ ligands can improve cardiac function and ameliorate the pathological progression of cardiac hypertrophy, heart failure, cardiac oxidative damage, ischemia-reperfusion injury, lipotoxic cardiac dysfunction and lipid-induced cardiac inflammation. Most of these findings have been observed in preclinical studies and it remains to be established to what extent these intriguing observations can be translated into clinical practice. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.
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Affiliation(s)
- Xavier Palomer
- Pharmacology Unit, Department of Pharmacology and Therapeutic Chemistry, Institut de Biomedicina de la UB (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain; Institut de Recerca Pediàtrica, Hospital Sant Joan de Déu, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain
| | - Emma Barroso
- Pharmacology Unit, Department of Pharmacology and Therapeutic Chemistry, Institut de Biomedicina de la UB (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain; Institut de Recerca Pediàtrica, Hospital Sant Joan de Déu, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain
| | - Mohammad Zarei
- Pharmacology Unit, Department of Pharmacology and Therapeutic Chemistry, Institut de Biomedicina de la UB (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain; Institut de Recerca Pediàtrica, Hospital Sant Joan de Déu, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain
| | - Gaia Botteri
- Pharmacology Unit, Department of Pharmacology and Therapeutic Chemistry, Institut de Biomedicina de la UB (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain; Institut de Recerca Pediàtrica, Hospital Sant Joan de Déu, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain
| | - Manuel Vázquez-Carrera
- Pharmacology Unit, Department of Pharmacology and Therapeutic Chemistry, Institut de Biomedicina de la UB (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain; Institut de Recerca Pediàtrica, Hospital Sant Joan de Déu, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Barcelona, Spain.
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Saha L. Role of peroxisome proliferator-activated receptors alpha and gamma in gastric ulcer: An overview of experimental evidences. World J Gastrointest Pharmacol Ther 2015; 6:120-126. [PMID: 26558146 PMCID: PMC4635152 DOI: 10.4292/wjgpt.v6.i4.120] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 07/11/2015] [Accepted: 10/13/2015] [Indexed: 02/06/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear hormone receptor superfamily. Three subtypes, PPARα, PPARβ/δ, and PPARγ, have been identified so far. PPARα is expressed in the liver, kidney, small intestine, heart, and muscle, where it activates the fatty acid catabolism and control lipoprotein assembly in response to long-chain unsaturated fatty acids, eicosanoids, and hypolipidemic drugs (e.g., fenofibrate). PPARβ/δ is more broadly expressed and is implicated in fatty acid oxidation, keratinocyte differentiation, wound healing, and macrophage response to very low density lipoprotein metabolism. This isoform has been implicated in transcriptional-repression functions and has been shown to repress the activity of PPARα or PPARγ target genes. PPARγ1 and γ2 are generated from a single-gene peroxisome proliferator-activated receptors gamma by differential promoter usage and alternative splicing. PPARγ1 is expressed in colon, immune system (e.g., monocytes and macrophages), and other tissues where it participates in the modulation of inflammation, cell proliferation, and differentiation. PPARs regulate gene expression through distinct mechanisms: Ligand-dependent transactivation, ligand-independent repression, and ligand-dependent transrepression. Studies in animals have demonstrated the gastric antisecretory activity of PPARα agonists like ciprofibrate, bezafibrate and clofibrate. Study by Pathak et al also demonstrated the effect of PPARα agonist, bezafibrate, on gastric secretion and gastric cytoprotection in various gastric ulcer models in rats. The majority of the experimental studies is on pioglitazone and rosiglitazone, which are PPARγ activators. In all the studies, both the PPARγ activators showed protection against the gastric ulcer and also accelerate the ulcer healing in gastric ulcer model in rats. Therefore, PPARα and PPARγ may be a target for gastric ulcer therapy. Finally, more studies are also needed to confirm the involvement of PPARs α and γ in gastric ulcer.
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Kleinhenz JM, Murphy TC, Pokutta-Paskaleva AP, Gleason RL, Lyle AN, Taylor WR, Blount MA, Cheng J, Yang Q, Sutliff RL, Hart CM. Smooth Muscle-Targeted Overexpression of Peroxisome Proliferator Activated Receptor-γ Disrupts Vascular Wall Structure and Function. PLoS One 2015; 10:e0139756. [PMID: 26451838 PMCID: PMC4599849 DOI: 10.1371/journal.pone.0139756] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 09/15/2015] [Indexed: 12/15/2022] Open
Abstract
Activation of the nuclear hormone receptor, PPARγ, with pharmacological agonists promotes a contractile vascular smooth muscle cell phenotype and reduces oxidative stress and cell proliferation, particularly under pathological conditions including vascular injury, restenosis, and atherosclerosis. However, pharmacological agonists activate both PPARγ-dependent and -independent mechanisms in multiple cell types confounding efforts to clarify the precise role of PPARγ in smooth muscle cell structure and function in vivo. We, therefore, designed and characterized a mouse model with smooth muscle cell-targeted PPARγ overexpression (smPPARγOE). Our results demonstrate that smPPARγOE attenuated contractile responses in aortic rings, increased aortic compliance, caused aortic dilatation, and reduced mean arterial pressure. Molecular characterization revealed that compared to littermate control mice, aortas from smPPARγOE mice expressed lower levels of contractile proteins and increased levels of adipocyte-specific transcripts. Morphological analysis demonstrated increased lipid deposition in the vascular media and in smooth muscle of extravascular tissues. In vitro adenoviral-mediated PPARγ overexpression in human aortic smooth muscle cells similarly increased adipocyte markers and lipid uptake. The findings demonstrate that smooth muscle PPARγ overexpression disrupts vascular wall structure and function, emphasizing that balanced PPARγ activity is essential for vascular smooth muscle homeostasis.
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Affiliation(s)
- Jennifer M. Kleinhenz
- Atlanta VA Medical Center, Decatur, GA, United States of America
- Emory University, Atlanta, GA, United States of America
| | - Tamara C. Murphy
- Atlanta VA Medical Center, Decatur, GA, United States of America
- Emory University, Atlanta, GA, United States of America
| | | | | | | | - W. Robert Taylor
- Atlanta VA Medical Center, Decatur, GA, United States of America
- Emory University, Atlanta, GA, United States of America
- Georgia Institute of Technology, Atlanta, GA, United States of America
| | | | - Juan Cheng
- Emory University, Atlanta, GA, United States of America
| | - Qinglin Yang
- University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Roy L. Sutliff
- Atlanta VA Medical Center, Decatur, GA, United States of America
- Emory University, Atlanta, GA, United States of America
| | - C. Michael Hart
- Atlanta VA Medical Center, Decatur, GA, United States of America
- Emory University, Atlanta, GA, United States of America
- * E-mail:
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Liu SL, Peng BJ, Zhong YL, Liu YL, Song Z, Wang Z. Effect of 5-caffeoylquinic acid on the NF-κB signaling pathway, peroxisome proliferator-activated receptor gamma 2, and macrophage infiltration in high-fat diet-fed Sprague-Dawley rat adipose tissue. Food Funct 2015; 6:2779-86. [PMID: 26158223 DOI: 10.1039/c5fo00626k] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Obesity, considered as a consequence of overnutrition, sustains a low-degree inflammatory state and results in insulin-resistance and type 2 diabetes. Here, we investigated the anti-inflammatory effects of 5-caffeoylquinic acid (5-CQA) in high-fat diet-induced obese rats. Serum interleukin (IL)-6, monocyte chemotactic protein 1 (MCP-1), tumor necrosis factor-alpha (TNF-α), total cholesterol (TC), triglyceride (TG), and free fatty acid (FFA) levels were determined. Expression of genes related to TG metabolism, macrophage biomarkers, and inflammation was assessed by real-time PCR. Protein expression of NF-κB, PPARγ2, and phosphorylated IκBα was evaluated by western blotting, and the histology of adipose tissue was examined. Supplementation of the rat diet with 5-CQA reduced obesity development, macrophage infiltration, and steatosis. Additionally, 5-CQA decreased the expression of NF-κB and downstream inflammatory cytokines, but increased the expression of PPARγ2, in a dose-dependent manner. Thus, 5-CQA improved obesity and obesity-related metabolic disturbances via PPARγ2 and the NF-κB signaling pathway.
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Affiliation(s)
- Si-Le Liu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, Hunan 410128, China.
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Lemkul JA, Lewis SN, Bassaganya-Riera J, Bevan DR. Phosphorylation of PPARγ Affects the Collective Motions of the PPARγ-RXRα-DNA Complex. PLoS One 2015; 10:e0123984. [PMID: 25954810 PMCID: PMC4425662 DOI: 10.1371/journal.pone.0123984] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 02/24/2015] [Indexed: 12/14/2022] Open
Abstract
Peroxisome-proliferator activated receptor-γ (PPARγ) is a nuclear hormone receptor that forms a heterodimeric complex with retinoid X receptor-α (RXRα) to regulate transcription of genes involved in fatty acid storage and glucose metabolism. PPARγ is a target for pharmaceutical intervention in type 2 diabetes, and insight into interactions between PPARγ, RXRα, and DNA is of interest in understanding the function and regulation of this complex. Phosphorylation of PPARγ by cyclin-dependent kinase 5 (Cdk5) has been shown to dysregulate the expression of metabolic regulation genes, an effect that is counteracted by PPARγ ligands. We applied molecular dynamics (MD) simulations to study the relationship between the ligand-binding domains of PPARγ and RXRα with their respective DNA-binding domains. Our results reveal that phosphorylation alters collective motions within the PPARγ-RXRα complex that affect the LBD-LBD dimerization interface and the AF-2 coactivator binding region of PPARγ.
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Affiliation(s)
- Justin A. Lemkul
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Stephanie N. Lewis
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
- Nutritional Immunology & Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Josep Bassaganya-Riera
- Nutritional Immunology & Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - David R. Bevan
- Department of Biochemistry, Virginia Tech, Blacksburg, Virginia, United States of America
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Katome T, Namekata K, Mitamura Y, Semba K, Egawa M, Naito T, Harada C, Harada T. Expression of intraocular peroxisome proliferator-activated receptor gamma in patients with proliferative diabetic retinopathy. J Diabetes Complications 2015; 29:275-81. [PMID: 25468312 DOI: 10.1016/j.jdiacomp.2014.10.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 10/18/2014] [Accepted: 10/21/2014] [Indexed: 11/16/2022]
Abstract
AIMS To determine whether peroxisome proliferator-activated receptor gamma (PPARγ), which is recognized as a component of the exosomes circulating in plasma, is expressed intraocularly in patients with proliferative diabetic retinopathy (PDR). METHODS The concentrations of PPARγ and vascular endothelial growth factor (VEGF) in the aqueous humor and vitreous of 50 eyes with PDR and 38 control eyes were determined by ELISA. The levels of the mRNA and protein of PPARγ were determined in proliferative membranes from 12 PDR and 5 control eyes by quantitative RT-PCR and immunohistochemical analyses. RESULTS PPARγ was detected in the culture media of human umbilical vein endothelial cells indicating that PPARγ can be released into the extracellular fluid. The PPARγ concentrations in the aqueous humor and vitreous fluid were significantly higher in PDR patients than in controls (P<0.0005). There was a significant positive correlation between the PPARγ and VEGF concentrations (P<0.0005). The level of PPARγ increased as the clinical stage advanced. The expressions of the mRNA and protein of PPARγ were higher in the membranes of PDR than those of controls. Anti-VEGF therapy significantly reduced the VEGF concentration (P<0.0001) but not the PPARγ concentration. CONCLUSIONS PPARγ may play an important role in the pathogenesis of PDR.
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Affiliation(s)
- Takashi Katome
- Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan; Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Kazuhiko Namekata
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Yoshinori Mitamura
- Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan.
| | - Kentaro Semba
- Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan; Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Mariko Egawa
- Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Takeshi Naito
- Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan
| | - Chikako Harada
- Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takayuki Harada
- Department of Ophthalmology, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima, Japan; Visual Research Project, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
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Rollins DA, Coppo M, Rogatsky I. Minireview: nuclear receptor coregulators of the p160 family: insights into inflammation and metabolism. Mol Endocrinol 2015; 29:502-17. [PMID: 25647480 DOI: 10.1210/me.2015-1005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nuclear receptor coactivators (NCOAs) are multifunctional transcriptional coregulators for a growing number of signal-activated transcription factors. The members of the p160 family (NCOA1/2/3) are increasingly recognized as essential and nonredundant players in a number of physiological processes. In particular, accumulating evidence points to the pivotal roles that these coregulators play in inflammatory and metabolic pathways, both under homeostasis and in disease. Given that chronic inflammation of metabolic tissues ("metainflammation") is a driving force for the widespread epidemic of obesity, insulin resistance, cardiovascular disease, and associated comorbidities, deciphering the role of NCOAs in "normal" vs "pathological" inflammation and in metabolic processes is indeed a subject of extreme biomedical importance. Here, we review the evolving and, at times, contradictory, literature on the pleiotropic functions of NCOA1/2/3 in inflammation and metabolism as related to nuclear receptor actions and beyond. We then briefly discuss the potential utility of NCOAs as predictive markers for disease and/or possible therapeutic targets once a better understanding of their molecular and physiological actions is achieved.
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Affiliation(s)
- David A Rollins
- Hospital for Special Surgery (D.A.R., M.C., I.R.), The David Rosensweig Genomics Center, New York, New York 10021; and Graduate Program in Immunology and Microbial Pathogenesis (D.A.R., I.R.), Weill Cornell Graduate School of Medical Sciences, New York, New York 10021
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Sato K, Sakai S, Kishi K, Tabata Y. Controlled release of pioglitazone from biodegradable hydrogels to modify macrophages phenotype. Inflamm Regen 2015. [DOI: 10.2492/inflammregen.35.086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Keisuke Sato
- Department of Biomaterials, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Shigeki Sakai
- Department of Plastic and Reconstructive Surgery, Keio University School of Medicine, Tokyo, Japan
- Department of Biomaterials, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Kazuo Kishi
- Department of Plastic and Reconstructive Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Yasuhiko Tabata
- Department of Biomaterials, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
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63
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Sansbury BE, Hill BG. Regulation of obesity and insulin resistance by nitric oxide. Free Radic Biol Med 2014; 73:383-99. [PMID: 24878261 PMCID: PMC4112002 DOI: 10.1016/j.freeradbiomed.2014.05.016] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 05/16/2014] [Accepted: 05/17/2014] [Indexed: 02/07/2023]
Abstract
Obesity is a risk factor for developing type 2 diabetes and cardiovascular disease and has quickly become a worldwide pandemic with few tangible and safe treatment options. Although it is generally accepted that the primary cause of obesity is energy imbalance, i.e., the calories consumed are greater than are utilized, understanding how caloric balance is regulated has proven a challenge. Many "distal" causes of obesity, such as the structural environment, occupation, and social influences, are exceedingly difficult to change or manipulate. Hence, molecular processes and pathways more proximal to the origins of obesity-those that directly regulate energy metabolism or caloric intake-seem to be more feasible targets for therapy. In particular, nitric oxide (NO) is emerging as a central regulator of energy metabolism and body composition. NO bioavailability is decreased in animal models of diet-induced obesity and in obese and insulin-resistant patients, and increasing NO output has remarkable effects on obesity and insulin resistance. This review discusses the role of NO in regulating adiposity and insulin sensitivity and places its modes of action into context with the known causes and consequences of metabolic disease.
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Affiliation(s)
- Brian E Sansbury
- Diabetes and Obesity Center, Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, USA
| | - Bradford G Hill
- Diabetes and Obesity Center, Institute of Molecular Cardiology, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, USA; Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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64
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Guertin MJ, Zhang X, Coonrod SA, Hager GL. Transient estrogen receptor binding and p300 redistribution support a squelching mechanism for estradiol-repressed genes. Mol Endocrinol 2014; 28:1522-33. [PMID: 25051172 DOI: 10.1210/me.2014-1130] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Proper gene regulation is essential for proper organismal development and appropriate responses to external stimuli. Specialized factors, termed master regulators, are often responsible for orchestrating the molecular events that result from signaling cascades. Master regulators coordinate the activation and repression of specific gene classes. Estrogen receptor α (ER) precipitates the signaling cascade that results from endogenous or exogenous estrogen hormones. ER is a classic transcriptional activator and the mechanisms by which ER coordinates gene activation are well characterized. However, it remains unclear how ER coordinates the immediate repression of genes. We integrated genomic transcription, chromosome looping, transcription factor binding, and chromatin structure data to analyze the molecular cascade that results from estradiol (E2)-induced signaling in human MCF-7 breast cancer cells and addressed the context-specific nature of gene regulation. We defined a class of genes that are immediately repressed upon estrogen stimulation, and we compared and contrasted the molecular characteristics of these repressed genes vs activated and unregulated genes. The most striking and unique feature of the repressed gene class is transient binding of ER at early time points after estrogen stimulation. We also found that p300, a coactivator and acetyltransferase, quantitatively redistributes from non-ER enhancers to ER enhancers after E2 treatment. These data support an extension of the classic physiological squelching model, whereby ER hijacks coactivators from repressed genes and redistributes the coactivators to ER enhancers that activate transcription.
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Affiliation(s)
- Michael J Guertin
- Laboratory of Receptor Biology and Gene Expression (M.J.G., G.L.H.), National Cancer Institute, Bethesda, Maryland 20892; State Key Laboratory of Reproductive Medicine (X.Z.), Nanjing Medical University, Nanjing 210029, China; and Baker Institute for Animal Health (X.Z., S.A.C.), College of Veterinary Medicine, Cornell University, Ithaca, New York 14853
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65
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Li CC, Hou YC, Yeh CL, Yeh SL. Effects of eicosapentaenoic acid and docosahexaenoic acid on prostate cancer cell migration and invasion induced by tumor-associated macrophages. PLoS One 2014; 9:e99630. [PMID: 24925287 PMCID: PMC4055683 DOI: 10.1371/journal.pone.0099630] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Accepted: 05/17/2014] [Indexed: 01/09/2023] Open
Abstract
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the major n-3 polyunsaturated fatty acids (PUFAs) in fish oil that decrease the risk of prostate cancer. Tumor-associated macrophages (TAMs) are the main leukocytes of intratumoral infiltration, and increased TAMs correlates with poor prostate cancer prognosis. However, the mechanism of n-3 PUFAs on prostate cancer cell progression induced by TAMs is not well understood. In this study, we investigated the effects of EPA and DHA on modulating of migration and invasion of prostate cancer cells induced by TAMs-like M2-type macrophages. PC-3 prostate cancer cells were pretreated with EPA, DHA, or the peroxisome proliferator-activated receptor (PPAR)-γ antagonist, GW9662, before exposure to conditioned medium (CM). CM was derived from M2-polarized THP-1 macrophages. The migratory and invasive abilities of PC-3 cells were evaluated using a coculture system of M2-type macrophages and PC-3 cells. EPA/DHA administration decreased migration and invasion of PC-3 cells. The PPAR-γ DNA-binding activity and cytosolic inhibitory factor κBα (IκBα) protein expression increased while the nuclear factor (NF)-κB p65 transcriptional activity and nuclear NF-κB p65 protein level decreased in PC-3 cells incubated with CM in the presence of EPA/DHA. Further, EPA/DHA downregulated mRNA expressions of matrix metalloproteinase-9, cyclooxygenase-2, vascular endothelial growth factor, and macrophage colony-stimulating factor. Pretreatment with GW9662 abolished the favorable effects of EPA/DHA on PC-3 cells. These results indicate that EPA/DHA administration reduced migration, invasion and macrophage chemotaxis of PC-3 cells induced by TAM-like M2-type macrophages, which may partly be explained by activation of PPAR-γ and decreased NF-κB p65 transcriptional activity.
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Affiliation(s)
- Cheng-Chung Li
- School of Nutrition and Health Sciences, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan
| | - Yu-Chen Hou
- Department of Surgery, National Taiwan University, Taipei, Taiwan
| | - Chiu-Li Yeh
- Department of Nutrition and Health Sciences, Chinese Culture University, Taipei, Taiwan
| | - Sung-Ling Yeh
- School of Nutrition and Health Sciences, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan
- * E-mail:
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66
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Step SE, Lim HW, Marinis JM, Prokesch A, Steger DJ, You SH, Won KJ, Lazar MA. Anti-diabetic rosiglitazone remodels the adipocyte transcriptome by redistributing transcription to PPARγ-driven enhancers. Genes Dev 2014; 28:1018-28. [PMID: 24788520 PMCID: PMC4018489 DOI: 10.1101/gad.237628.114] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Rosiglitazone (rosi) is a powerful insulin sensitizer, but serious toxicities have curtailed its widespread clinical use. Rosi functions as a high-affinity ligand for PPARγ, the adipocyte-predominant nuclear receptor. Here, Lazar and colleagues investigate the direct effects of rosi on gene transcription. The authors delineate a novel mechanism by which rosi represses adipocyte gene transcription at endogenous levels of PPARγ and other transcription factors on a genome-wide scale. This study suggests that rosi activates and represses transcription by fundamentally different mechanisms that could inform anti-diabetic drug development. Rosiglitazone (rosi) is a powerful insulin sensitizer, but serious toxicities have curtailed its widespread clinical use. Rosi functions as a high-affinity ligand for peroxisome proliferator-activated receptor γ (PPARγ), the adipocyte-predominant nuclear receptor (NR). The classic model, involving binding of ligand to the NR on DNA, explains positive regulation of gene expression, but ligand-dependent repression is not well understood. We addressed this issue by studying the direct effects of rosi on gene transcription using global run-on sequencing (GRO-seq). Rosi-induced changes in gene body transcription were pronounced after 10 min and correlated with steady-state mRNA levels as well as with transcription at nearby enhancers (enhancer RNAs [eRNAs]). Up-regulated eRNAs occurred almost exclusively at PPARγ-binding sites, to which rosi treatment recruited coactivators, including MED1, p300, and CBP. In contrast, transcriptional repression by rosi involved a loss of coactivators from eRNA sites devoid of PPARγ and enriched for other transcription factors, including AP-1 factors and C/EBPs. Thus, rosi activates and represses transcription by fundamentally different mechanisms that could inform the future development of anti-diabetic drugs.
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Affiliation(s)
- Sonia E Step
- Division of Endocrinology, Diabetes, and Metabolism
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67
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Chen Y, Zhang X, Yang L, Li M, Li B, Wang W, Sheng M. Decreased PPAR-γ expression in the conjunctiva and increased expression of TNF-α and IL-1β in the conjunctiva and tear fluid of dry eye mice. Mol Med Rep 2014; 9:2015-23. [PMID: 24626526 DOI: 10.3892/mmr.2014.2041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 02/25/2014] [Indexed: 11/05/2022] Open
Abstract
The aim of this study was to investigate the expression of peroxisome proliferator-activated receptor γ (PPAR-γ), tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the conjunctiva and the association between inflammatory cytokines and PPAR-γ in dry eye mice. Dry eye was induced in 6-week-old female C57 mice. mRNA expression of PPAR-γ, TNF-α and IL-1β were measured. PPAR-γ protein expression in the conjunctiva, and the contents of TNF-α and IL-1β in the conjunctiva and tear-wash fluid were determined. A PPAR-γ agonist, pioglitazone (PIO), was used to treat dry eye mice. Dry eye mice presented with similar manifestations as in humans. The PPAR-γ expression in the conjunctiva of dry eye mice was downregulated, accompanied by increased contents of TNF-α and IL-1β. PIO treatment markedly reduced the contents of TNF-α and IL-1β in tear fluid of dry eye mice. Following PIO treatment, the PPAR-γ expression increased markedly. PIO may activate PPAR-γ to inhibit the expression of the inflammatory cytokines TNF-α and IL-1β in dry eye mice. This suppresses the inflammatory progression, increases the tear fluid production, elevates the tear film stability and reduces the damage to the ocular surface, exerting a therapeutic effect on dry eye.
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Affiliation(s)
- Yihui Chen
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P.R. China
| | - Xiaoyan Zhang
- Department of Ophthalmology, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Ling Yang
- Department of Ophthalmology, Luwan Branch of Ruijin Hospital, Shanghai Jiaotong University, Shanghai 200020, P.R. China
| | - Min Li
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P.R. China
| | - Bing Li
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P.R. China
| | - Weifang Wang
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P.R. China
| | - Minjie Sheng
- Department of Ophthalmology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P.R. China
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68
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Regoli F, Giuliani ME. Oxidative pathways of chemical toxicity and oxidative stress biomarkers in marine organisms. MARINE ENVIRONMENTAL RESEARCH 2014; 93:106-17. [PMID: 23942183 DOI: 10.1016/j.marenvres.2013.07.006] [Citation(s) in RCA: 538] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/16/2013] [Accepted: 07/17/2013] [Indexed: 05/04/2023]
Abstract
The antioxidant system of marine organisms consists of low molecular weight scavengers and antioxidant enzymes which interact in a sophisticated network. Environmental pollutants can unbalance this system through closely related mechanisms, indirect relationships and cascade effects acting from pre-transcriptional to catalytic levels. Chemically-mediated pathways have the potential to greatly enhance intracellular formation of reactive oxygen species (ROS); at the same time, excessive levels of oxyradicals down-regulate xenobiotics metabolism, with important environmental implications for organisms exposed to chemical mixtures. Interactions between different classes of chemicals, generation of ROS and onset of oxidative stress conditions are partly modulated by changes in levels and functions of redox-sensitive signaling proteins and transcription factors. The Nrf2-Keap1 pathway still remains largely unexplored in marine organisms, despite the elevated degree of identity and similarity with homolog transcripts and proteins from different species. Recent evidences on transcriptional up-regulation of this system are consistent with the capability to provide a prolonged expression of ARE-regulated cytoprotective genes, and to efficiently switch off this mechanism when oxidative pressure decreases. Although gene expression and catalytic activities of antioxidants are often measured as alternative biomarkers in monitoring biological effects of contaminants, conflicting results between molecular and biochemical responses are quite frequent. The links between effects occurring at various intracellular levels can be masked by non-genomic processes affecting mRNA stability and protein turnover, different timing for transcriptional and translational mechanisms, metabolic capability of tissues, post-transcriptional modifications of proteins, bi-phasic responses of antioxidant enzymes and interactions occurring in chemical mixtures. In this respect, caution should be taken in monitoring studies where mRNA levels of antioxidants could represent a snapshot of cell activity at a given time, not an effective endpoint of environmental pollutants.
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Affiliation(s)
- Francesco Regoli
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Ranieri Monte d'Ago, Ancona 60100, Italy.
| | - Maria Elisa Giuliani
- Dipartimento di Scienze della Vita e dell'Ambiente, Università Politecnica delle Marche, Via Ranieri Monte d'Ago, Ancona 60100, Italy
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69
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Ferreira AE, Sisti F, Sônego F, Wang S, Filgueiras LR, Brandt S, Serezani APM, Du H, Cunha FQ, Alves-Filho JC, Serezani CH. PPAR-γ/IL-10 axis inhibits MyD88 expression and ameliorates murine polymicrobial sepsis. THE JOURNAL OF IMMUNOLOGY 2014; 192:2357-65. [PMID: 24489087 DOI: 10.4049/jimmunol.1302375] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Polymicrobial sepsis induces organ failure and is accompanied by overwhelming inflammatory response and impairment of microbial killing. Peroxisome proliferator-activated receptor (PPAR)-γ is a nuclear receptor with pleiotropic effects on lipid metabolism, inflammation, and cell proliferation. The insulin-sensitizing drugs thiazolidinediones (TZDs) are specific PPAR-γ agonists. TZDs exert anti-inflammatory actions in different disease models, including polymicrobial sepsis. The TZD pioglitazone, which has been approved by the U.S. Food and Drug Administration, improves sepsis outcome; however, the molecular programs that mediate its effect have not been determined. In a murine model of sepsis, we now show that pioglitazone treatment improves microbial clearance and enhances neutrophil recruitment to the site of infection. We also observed reduced proinflammatory cytokine production and high IL-10 levels in pioglitazone-treated mice. These effects were associated with a decrease in STAT-1-dependent expression of MyD88 in vivo and in vitro. IL-10R blockage abolished PPAR-γ-mediated inhibition of MyD88 expression. These data demonstrate that the primary mechanism by which pioglitazone protects against polymicrobial sepsis is through the impairment of MyD88 responses. This appears to represent a novel regulatory program. In this regard, pioglitazone provides advantages as a therapeutic tool, because it improves different aspects of host defense during sepsis, ultimately enhancing survival.
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Affiliation(s)
- Ana Elisa Ferreira
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN 46202
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70
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Lakshmi SP, Reddy AT, Zhang Y, Sciurba FC, Mallampalli RK, Duncan SR, Reddy RC. Down-regulated peroxisome proliferator-activated receptor γ (PPARγ) in lung epithelial cells promotes a PPARγ agonist-reversible proinflammatory phenotype in chronic obstructive pulmonary disease (COPD). J Biol Chem 2013; 289:6383-6393. [PMID: 24368768 DOI: 10.1074/jbc.m113.536805] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory condition and a leading cause of death, with no available cure. We assessed the actions in pulmonary epithelial cells of peroxisome proliferator-activated receptor γ (PPARγ), a nuclear hormone receptor with anti-inflammatory effects, whose role in COPD is largely unknown. We found that PPARγ was down-regulated in lung tissue and epithelial cells of COPD patients, via both reduced expression and phosphorylation-mediated inhibition, whereas pro-inflammatory nuclear factor-κB (NF-κB) activity was increased. Cigarette smoking is the main risk factor for COPD, and exposing airway epithelial cells to cigarette smoke extract (CSE) likewise down-regulated PPARγ and activated NF-κB. CSE also down-regulated and post-translationally inhibited the glucocorticoid receptor (GR-α) and histone deacetylase 2 (HDAC2), a corepressor important for glucocorticoid action and whose down-regulation is thought to cause glucocorticoid insensitivity in COPD. Treating epithelial cells with synthetic (rosiglitazone) or endogenous (10-nitro-oleic acid) PPARγ agonists strongly up-regulated PPARγ expression and activity, suppressed CSE-induced production and secretion of inflammatory cytokines, and reversed its activation of NF-κB by inhibiting the IκB kinase pathway and by promoting direct inhibitory binding of PPARγ to NF-κB. In contrast, PPARγ knockdown via siRNA augmented CSE-induced chemokine release and decreases in HDAC activity, suggesting a potential anti-inflammatory role of endogenous PPARγ. The results imply that down-regulation of pulmonary epithelial PPARγ by cigarette smoke promotes inflammatory pathways and diminishes glucocorticoid responsiveness, thereby contributing to COPD pathogenesis, and further suggest that PPARγ agonists may be useful for COPD treatment.
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Affiliation(s)
- Sowmya P Lakshmi
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15240
| | - Aravind T Reddy
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15240
| | - Yingze Zhang
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Frank C Sciurba
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Rama K Mallampalli
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15240
| | - Steven R Duncan
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Raju C Reddy
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania 15240.
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71
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Li CC, Yang HT, Hou YC, Chiu YS, Chiu WC. Dietary fish oil reduces systemic inflammation and ameliorates sepsis-induced liver injury by up-regulating the peroxisome proliferator-activated receptor gamma-mediated pathway in septic mice. J Nutr Biochem 2013; 25:19-25. [PMID: 24314861 DOI: 10.1016/j.jnutbio.2013.08.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/15/2013] [Accepted: 08/21/2013] [Indexed: 12/28/2022]
Abstract
This study investigated the effect of dietary fish oil on systemic inflammation and hepatic injury in mice with polymicrobial sepsis. Male ICR mice were assigned to a control group (C, n=30) and a fish oil group (FO, n=30). Mice in the C group were fed a semi-purified diet with 10% soybean oil, and those in the FO group were fed a fish oil diet (2.5% fish oil+7.5% soybean oil; w/w). Three weeks later, sepsis was induced by cecal ligation and puncture (CLP), and mice were sacrificed at 0, 6 and 24 h after CLP, respectively. Results showed that compared with C group, the FO group had lower plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and nitrite at 6 and 24 h after CLP. Also, peritoneal lavage fluid concentrations of TNF-α and prostaglandin (PG) E2 were significantly lower at 24 h in the FO than in the C group. The FO group had lower myeloperoxidase activities at 6 h after CLP in various organs. Plasma aminotransferase and alanine aminotransferase activities revealed significantly decreased in the FO group. The DNA-binding activity of peroxisome proliferators-activated receptor gamma (PPARγ) and mRNA expression of I kappaB alpha (IκBα) were up-regulated while nuclear factor (NF)-κB p65 DNA-binding activity, inducible nitric oxide synthase protein expression and the concentration of nitrotyrosine were significantly decreased in the FO group in liver after CLP. These results indicate that dietary fish oil administration may attenuate systemic inflammation and up-regulate hepatic PPARγ DNA-binding activity, which may consequently have ameliorated liver injury in these septic mice.
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Affiliation(s)
- Cheng-Chung Li
- School of Nutrition and Health Sciences, Taipei Medical University, Taipei 110, Taiwan
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72
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Reddy AT, Lakshmi SP, Dornadula S, Pinni S, Rampa DR, Reddy RC. The nitrated fatty acid 10-nitro-oleate attenuates allergic airway disease. THE JOURNAL OF IMMUNOLOGY 2013; 191:2053-63. [PMID: 23913958 DOI: 10.4049/jimmunol.1300730] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Asthma is a serious, growing problem worldwide. Inhaled steroids, the current standard therapy, are not always effective in this chronic inflammatory disease and can cause adverse effects. We tested the hypothesis that nitrated fatty acids (NFAs) may provide an effective alternative treatment. NFAs are endogenously produced by nonenzymatic reaction of NO with unsaturated fatty acids and exert anti-inflammatory actions both by activating the nuclear hormone receptor peroxisome proliferator-activated receptor (PPAR)γ and via PPAR-independent mechanisms, but whether they might ameliorate allergic airway disease was previously untested. We found that pulmonary delivery of the NFA 10-nitro-oleic acid (OA-NO2) reduced the severity of murine allergic airway disease, as assessed by various pathological and molecular markers. Fluticasone, an inhaled steroid commonly used to treat asthma, produced similar effects on most end points, but only OA-NO2 induced robust apoptosis of neutrophils and their phagocytosis by alveolar macrophages. This suggests that OA-NO2 may be particularly effective in neutrophil-rich, steroid-resistant severe asthma. In primary human bronchial epithelial cells, OA-NO2 blocked phosphorylation and degradation of IκB and enhanced inhibitory binding of PPARγ to NF-κB. Our results indicate that the NFA OA-NO2 is efficacious in preclinical models of allergic airway disease and may have potential for treating asthma patients.
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Affiliation(s)
- Aravind T Reddy
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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73
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Resolution of inflammation: mechanisms and opportunity for drug development. Pharmacol Ther 2013; 139:189-212. [PMID: 23583354 DOI: 10.1016/j.pharmthera.2013.04.006] [Citation(s) in RCA: 153] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 04/01/2013] [Indexed: 12/12/2022]
Abstract
Inflammation is a beneficial host reaction to tissue damage and has the essential primary purpose of restoring tissue homeostasis. Inflammation plays a major role in containing and resolving infection and may also occur under sterile conditions. The cardinal signs of inflammation dolor, calor, tumor and rubor are intrinsically associated with events including vasodilatation, edema and leukocyte trafficking into the site of inflammation. If uncontrolled or unresolved, inflammation itself can lead to further tissue damage and give rise to chronic inflammatory diseases and autoimmunity with eventual loss of organ function. It is now evident that the resolution of inflammation is an active continuous process that occurs during an acute inflammatory episode. Successful resolution requires activation of endogenous programs with switch from production of pro-inflammatory towards pro-resolving molecules, such as specific lipid mediators and annexin A1, and the non-phlogistic elimination of granulocytes by apoptosis with subsequent removal by surrounding macrophages. These processes ensure rapid restoration of tissue homeostasis. Here, we review recent advances in the understanding of resolution of inflammation, highlighting the pharmacological strategies that may interfere with the molecular pathways which control leukocyte survival and clearance. Such strategies have proved beneficial in several pre-clinical models of inflammatory diseases, suggesting that pharmacological modulation of the resolution process may be useful for the treatment of chronic inflammatory diseases in humans.
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74
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Burris TP, Solt LA, Wang Y, Crumbley C, Banerjee S, Griffett K, Lundasen T, Hughes T, Kojetin DJ. Nuclear receptors and their selective pharmacologic modulators. Pharmacol Rev 2013; 65:710-78. [PMID: 23457206 PMCID: PMC11060414 DOI: 10.1124/pr.112.006833] [Citation(s) in RCA: 180] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Nuclear receptors are ligand-activated transcription factors and include the receptors for steroid hormones, lipophilic vitamins, sterols, and bile acids. These receptors serve as targets for development of myriad drugs that target a range of disorders. Classically defined ligands that bind to the ligand-binding domain of nuclear receptors, whether they are endogenous or synthetic, either activate receptor activity (agonists) or block activation (antagonists) and due to the ability to alter activity of the receptors are often termed receptor "modulators." The complex pharmacology of nuclear receptors has provided a class of ligands distinct from these simple modulators where ligands display agonist/partial agonist/antagonist function in a tissue or gene selective manner. This class of ligands is defined as selective modulators. Here, we review the development and pharmacology of a range of selective nuclear receptor modulators.
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Affiliation(s)
- Thomas P Burris
- The Scripps Research Institute, 130 Scripps Way 2A1, Jupiter, FL 33458, USA.
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75
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Javadi S, Ejtemaeimehr S, Keyvanfar HR, Moghaddas P, Aminian A, Rajabzadeh A, Mani AR, Dehpour AR. Pioglitazone potentiates development of morphine-dependence in mice: possible role of NO/cGMP pathway. Brain Res 2013; 1510:22-37. [PMID: 23399681 DOI: 10.1016/j.brainres.2012.12.035] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/15/2012] [Accepted: 12/13/2012] [Indexed: 01/23/2023]
Abstract
Peroxizome proliferator-activated receptor gamma (PPARγ) is highly expressed in the central nervous system where it modulates numerous gene transcriptions. Nitric oxide synthase (NOS) expression could be modified by simulation of PPARγ which in turn activates nitric oxide (NO)/soluble guanylyl-cyclase (sGC)/cyclic guanosine mono phosphate (cGMP) pathway. It is well known that NO/cGMP pathway possesses pivotal role in the development of opioid dependence and this study is aimed to investigate the effect of PPARγ stimulation on opioid dependence in mice as well as human glioblastoma cell line. Pioglitazone potentiated naloxone-induced withdrawal syndrome in morphine dependent mice in vivo. While selective inhibition of PPARγ, neuronal NOS or GC could reverse the pioglitazone-induced potentiation of morphine withdrawal signs; sildenafil, a phosphodiesterase-5 inhibitor amplified its effect. We also showed that nitrite levels in the hippocampus were significantly elevated in pioglitazone-treated morphine dependent mice. In the human glioblastoma (U87) cell line, rendered dependent to morphine, cAMP levels did not show any alteration after chronic pioglitazone administration while cGMP measurement revealed a significant rise. We were unable to show a significant alteration in neuronal NOS mRNA expressions by pioglitazone in mice hippocampus or U87 cells. Our results suggest that pioglitazone has the ability to enhance morphine-dependence and to augment morphine withdrawal signs. The possible pathway underlying this effect is through activation of NO/GC/cGMP pathway.
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Affiliation(s)
- Shiva Javadi
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box 13145-784, Tehran, Iran
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76
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Czimmerer Z, Varga T, Poliska S, Nemet I, Szanto A, Nagy L. Identification of novel markers of alternative activation and potential endogenous PPARγ ligand production mechanisms in human IL-4 stimulated differentiating macrophages. Immunobiology 2012; 217:1301-14. [PMID: 22954708 DOI: 10.1016/j.imbio.2012.08.270] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 07/30/2012] [Accepted: 08/02/2012] [Indexed: 01/28/2023]
Affiliation(s)
- Zsolt Czimmerer
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Life Science Building, Egyetem ter 1, Debrecen H-4012, Hungary
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77
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Ferreira AM, Minarrieta L, Lamas Bervejillo M, Rubbo H. Nitro-fatty acids as novel electrophilic ligands for peroxisome proliferator-activated receptors. Free Radic Biol Med 2012; 53:1654-63. [PMID: 22982052 DOI: 10.1016/j.freeradbiomed.2012.08.572] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 08/16/2012] [Accepted: 08/17/2012] [Indexed: 11/30/2022]
Abstract
Lipid nitration has been observed during oxidative/nitrative stress conditions generating a variety of biomolecules capable of modulating cellular responses. This concept has grown as a result of studies with nitro-derivatives of long-chain unsaturated fatty acids containing a nitroalkene group (nitro-fatty acids). This review focuses on the interactions of nitro-fatty acids with members of the peroxisome proliferator-activated receptors (PPARs) family. These nuclear receptors belong to a superfamily of ligand-activated transcription factors, which serve as sensors of lipophilic molecules and regulate the expression of a set of genes involved in glucose and lipid metabolism. Here we discuss how nitro-fatty acids bind and activate PPARs, including the current knowledge of the molecular interactions and cell signaling events involved as well as their therapeutic potential associated with chronic inflammation and metabolic disorders.
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Affiliation(s)
- Ana M Ferreira
- Cátedra de Inmunología, Facultad de Ciencias/Química, Universidad de la República, Montevideo, Uruguay
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78
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Viladomiu M, Hontecillas R, Pedragosa M, Carbo A, Hoops S, Michalak P, Michalak K, Guerrant RL, Roche JK, Warren CA, Bassaganya-Riera J. Modeling the role of peroxisome proliferator-activated receptor γ and microRNA-146 in mucosal immune responses to Clostridium difficile. PLoS One 2012; 7:e47525. [PMID: 23071818 PMCID: PMC3469550 DOI: 10.1371/journal.pone.0047525] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Accepted: 09/12/2012] [Indexed: 12/15/2022] Open
Abstract
Clostridium difficile is an anaerobic bacterium that has re-emerged as a facultative pathogen and can cause nosocomial diarrhea, colitis or even death. Peroxisome proliferator-activated receptor (PPAR) γ has been implicated in the prevention of inflammation in autoimmune and infectious diseases; however, its role in the immunoregulatory mechanisms modulating host responses to C. difficile and its toxins remains largely unknown. To characterize the role of PPARγ in C. difficile-associated disease (CDAD), immunity and gut pathology, we used a mouse model of C. difficile infection in wild-type and T cell-specific PPARγ null mice. The loss of PPARγ in T cells increased disease activity and colonic inflammatory lesions following C. difficile infection. Colonic expression of IL-17 was upregulated and IL-10 downregulated in colons of T cell-specific PPARγ null mice. Also, both the loss of PPARγ in T cells and C. difficile infection favored Th17 responses in spleen and colonic lamina propria of mice with CDAD. MicroRNA (miRNA)-sequencing analysis and RT-PCR validation indicated that miR-146b was significantly overexpressed and nuclear receptor co-activator 4 (NCOA4) suppressed in colons of C. difficile-infected mice. We next developed a computational model that predicts the upregulation of miR-146b, downregulation of the PPARγ co-activator NCOA4, and PPARγ, leading to upregulation of IL-17. Oral treatment of C. difficile-infected mice with the PPARγ agonist pioglitazone ameliorated colitis and suppressed pro-inflammatory gene expression. In conclusion, our data indicates that miRNA-146b and PPARγ activation may be implicated in the regulation of Th17 responses and colitis in C. difficile-infected mice.
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Affiliation(s)
- Monica Viladomiu
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Raquel Hontecillas
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Mireia Pedragosa
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Adria Carbo
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Stefan Hoops
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Pawel Michalak
- Medical Informatics and Systems Division, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Katarzyna Michalak
- Medical Informatics and Systems Division, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Richard L. Guerrant
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
- Division of Infectious Disease and International Health, Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - James K. Roche
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
- Division of Infectious Disease and International Health, Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Cirle A. Warren
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
- Division of Infectious Disease and International Health, Center for Global Health, University of Virginia, Charlottesville, Virginia, United States of America
| | - Josep Bassaganya-Riera
- Nutritional Immunology and Molecular Medicine Laboratory, Virginia Bioinformatics Institute, Virginia Tech, Blacksburg, Virginia, United States of America
- Center for Modeling Immunity to Enteric Pathogens, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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79
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Fucci A, Colangelo T, Votino C, Pancione M, Sabatino L, Colantuoni V. The role of peroxisome proliferator-activated receptors in the esophageal, gastric, and colorectal cancer. PPAR Res 2012; 2012:242498. [PMID: 22991505 PMCID: PMC3444044 DOI: 10.1155/2012/242498] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2012] [Accepted: 07/24/2012] [Indexed: 12/21/2022] Open
Abstract
Tumors of the gastrointestinal tract are among the most frequent human malignancies and account for approximately 30% of cancer-related deaths worldwide. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that control diverse cellular functions such as proliferation, differentiation, and cell death. Owing to their involvement in so many processes, they play crucial roles also in the development and physiology of the gastrointestinal tract. Consistently, PPARs deregulation has been implicated in several pathophysiological conditions, including chronic inflammation and cancer development. This paper summarizes the current knowledge on the role that the various PPAR isoforms play in the pathogenesis of the esophageal, gastric, and intestinal cancer. Elucidation of the molecular mechanisms underlying PPARs' signaling pathways will provide insights into their possible use as predictive biomarkers in the initial stages of the process. In addition, this understanding will provide the basis for new molecular targets in cancer therapy and chemoprevention.
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Affiliation(s)
- Alessandra Fucci
- Department of Biological, Geological and Environmental Sciences, University of Sannio, 82100 Benevento, Italy
| | - Tommaso Colangelo
- Department of Biological, Geological and Environmental Sciences, University of Sannio, 82100 Benevento, Italy
| | - Carolina Votino
- Department of Biological, Geological and Environmental Sciences, University of Sannio, 82100 Benevento, Italy
| | - Massimo Pancione
- Department of Biological, Geological and Environmental Sciences, University of Sannio, 82100 Benevento, Italy
| | - Lina Sabatino
- Department of Biological, Geological and Environmental Sciences, University of Sannio, 82100 Benevento, Italy
| | - Vittorio Colantuoni
- Department of Biological, Geological and Environmental Sciences, University of Sannio, 82100 Benevento, Italy
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80
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Majer O, Bourgeois C, Zwolanek F, Lassnig C, Kerjaschki D, Mack M, Müller M, Kuchler K. Type I interferons promote fatal immunopathology by regulating inflammatory monocytes and neutrophils during Candida infections. PLoS Pathog 2012; 8:e1002811. [PMID: 22911155 PMCID: PMC3406095 DOI: 10.1371/journal.ppat.1002811] [Citation(s) in RCA: 118] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 06/05/2012] [Indexed: 12/17/2022] Open
Abstract
Invasive fungal infections by Candida albicans (Ca) are a frequent cause of lethal sepsis in intensive care unit patients. While a contribution of type I interferons (IFNs-I) in fungal sepsis remains unknown, these immunostimulatory cytokines mediate the lethal effects of endotoxemia and bacterial sepsis. Using a mouse model lacking a functional IFN-I receptor (Ifnar1−/−), we demonstrate a remarkable protection against invasive Ca infections. We discover a mechanism whereby IFN-I signaling controls the recruitment of inflammatory myeloid cells, including Ly6Chi monocytes and neutrophils, to infected kidneys by driving expression of the chemokines CCL2 and KC. Within kidneys, monocytes differentiate into inflammatory DCs but fail to functionally mature in Ifnar1−/− mice, as demonstrated by the impaired upregulation of the key activation markers PDCA1 and iNOS. The increased activity of inflammatory monocytes and neutrophils results in hyper-inflammation and lethal kidney pathology. Pharmacological diminution of monocytes and neutrophils by treating mice with pioglitazone, a synthetic agonist of the nuclear receptor peroxisome proliferator-activated receptor-γ (PPAR-γ), strongly reduces renal immunopathology during Ca infection and improves mouse survival. Taken together, our data connect for the first time the sepsis-promoting functions of IFNs-I to the CCL2-mediated recruitment and the activation of inflammatory monocytes/DCs with high host-destructing potency. Moreover, our data demonstrate a therapeutic relevance of PPAR-γ agonists for microbial infectious diseases where inflammatory myeloid cells may contribute to fatal tissue damage. Inflammation constitutes a major host response in many microbial infections. Innate immune cells orchestrate the inflammatory response to kill pathogens and clear infections. However, invasive infections by pathogenic microbes including the fungus Candida albicans, can result in an uncontrolled hyper-inflammatory response, leading to severe host damage and sepsis. Type I interferons constitute a hallmark of protective innate immunity in viral and bacterial infections, but at the same time have been notoriously known for their sepsis-promoting effects in numerous experimental inflammation models. Here, we show that type I interferon-signaling mediates the lethal hyper-inflammatory response during systemic mouse infections with C. albicans. Following fungal infections, type I interferons promote the recruitment and activation of inflammatory monocytes and neutrophils to infected organs. The high abundance and activity of inflammatory phagocytes lead to fatal tissue damage. Remarkably, we show that the pharmacological suppression of these inflammatory cells with the drug pioglitazone reduces immunopathology and sepsis-related lethality, suggesting a novel therapeutic option to combat fungal sepsis. In conclusion, our data couple the sepsis-promoting role of type I interferons to the host-destructive activity of inflammatory monocytes and neutrophils. We propose that therapeutic approaches dampening hyper-inflammation might be of general importance in microbial diseases where deleterious immunopathology occurs.
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Affiliation(s)
- Olivia Majer
- Medical University Vienna-Max F. Perutz Laboratories, Christian Doppler Laboratory for Infection Biology, Campus Vienna Biocenter, Vienna, Austria
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81
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PPARG Epigenetic Deregulation and Its Role in Colorectal Tumorigenesis. PPAR Res 2012; 2012:687492. [PMID: 22848209 PMCID: PMC3405724 DOI: 10.1155/2012/687492] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 04/21/2012] [Indexed: 12/12/2022] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) plays critical roles in lipid storage, glucose metabolism, energy homeostasis, adipocyte differentiation, inflammation, and cancer. Its function in colon carcinogenesis has largely been debated; accumulating evidence, however, supports a role as tumor suppressor through modulation of crucial pathways in cell differentiation, apoptosis, and metastatic dissemination. Epigenetics adds a further layer of complexity to gene regulation in several biological processes. In cancer, the relationship with epigenetic modifications has provided important insights into the underlying molecular mechanisms. These studies have highlighted how epigenetic modifications influence PPARG gene expression in colorectal tumorigenesis. In this paper, we take a comprehensive look at the current understanding of the relationship between PPARγ and cancer development. The role that epigenetic mechanisms play is also addressed disclosing novel crosstalks between PPARG signaling and the epigenetic machinery and suggesting how this dysregulation may contribute to colon cancer development.
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82
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Jana M, Pahan K. Gemfibrozil, a lipid lowering drug, inhibits the activation of primary human microglia via peroxisome proliferator-activated receptor β. Neurochem Res 2012; 37:1718-29. [PMID: 22528839 DOI: 10.1007/s11064-012-0781-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 04/04/2012] [Accepted: 04/07/2012] [Indexed: 12/27/2022]
Abstract
Microglial activation participates in the pathogenesis of various neuroinflammatory and neurodegenerative diseases. However, mechanisms by which microglial activation could be controlled are poorly understood. Peroxisome proliferator-activated receptors (PPAR) are transcription factors belonging to the nuclear receptor super family with diverse effect. This study underlines the importance of PPARβ/δ in mediating the anti-inflammatory effect of gemfibrozil, an FDA-approved lipid-lowering drug, in primary human microglia. Bacterial lipopolysachharides (LPS) induced the expression of various proinflammatory molecules and upregulated the expression of microglial surface marker CD11b in human microglia. However, gemfibrozil markedly suppressed proinflammatory molecules and CD11b in LPS-stimulated microglia. Human microglia expressed PPAR-β and -γ, but not PPAR-α. Interestingly, either antisense knockdown of PPAR-β or antagonism of PPAR-β by a specific chemical antagonist abrogated gemfibrozil-mediated inhibition of microglial activation. On the other hand, blocking of PPAR-α and -γ had no effect on gemfibrozil-mediated anti-inflammatory effect in microglia. These results highlight the fact that gemfibrozil regulates microglial activation by inhibiting inflammatory gene expression in a PPAR-β dependent pathway and further reinforce its therapeutic application in several neuroinflammatory and neurodegenerative diseases.
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Affiliation(s)
- Malabendu Jana
- Department of Neurological Sciences, Rush University Medical Center, 1735 West Harrison St., Suite 320, Chicago, IL 60612, USA
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83
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Polvani S, Tarocchi M, Galli A. PPARγ and Oxidative Stress: Con(β) Catenating NRF2 and FOXO. PPAR Res 2012; 2012:641087. [PMID: 22481913 PMCID: PMC3317010 DOI: 10.1155/2012/641087] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 11/05/2011] [Accepted: 11/17/2011] [Indexed: 12/22/2022] Open
Abstract
Peroxisome-proliferator activator receptor γ (PPARγ) is a nuclear receptor of central importance in energy homeostasis and inflammation. Recent experimental pieces of evidence demonstrate that PPARγ is implicated in the oxidative stress response, an imbalance between antithetic prooxidation and antioxidation forces that may lead the cell to apoptotic or necrotic death. In this delicate and intricate game of equilibrium, PPARγ stands out as a central player devoted to the quenching and containment of the damage and to foster cell survival. However, PPARγ does not act alone: indeed the nuclear receptor is at the point of interconnection of various pathways, such as the nuclear factor erythroid 2-related factor 2 (NRF2), Wnt/β-catenin, and forkhead box proteins O (FOXO) pathways. Here we reviewed the role of PPARγ in response to oxidative stress and its interaction with other signaling pathways implicated in this process, an interaction that emerged as a potential new therapeutic target for several oxidative-related diseases.
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Affiliation(s)
- Simone Polvani
- Gastroenterology Unit, Department of Clinical Pathophysiology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy
| | - Mirko Tarocchi
- Gastroenterology Unit, Department of Clinical Pathophysiology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy
| | - Andrea Galli
- Gastroenterology Unit, Department of Clinical Pathophysiology, University of Florence, Viale Pieraccini 6, 50139 Firenze, Italy
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84
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Role of PPARs in Trypanosoma cruzi Infection: Implications for Chagas Disease Therapy. PPAR Res 2012; 2012:528435. [PMID: 22448167 PMCID: PMC3289900 DOI: 10.1155/2012/528435] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 11/03/2011] [Indexed: 01/04/2023] Open
Abstract
Chagas disease, which is caused by Trypanosoma cruzi (T. cruzi), remains a substantial public health concern and an important cause of morbidity and mortality in Latin America. T. cruzi infection causes an intense inflammatory response in diverse tissues by triggering local expression of inflammatory mediators, which results in the upregulation of the levels of cytokines and chemokines, and important cardiac alterations in the host, being one of the most characteristic damages of Chagas disease. Therefore, controlling the inflammatory reaction becomes critical for the control of the proliferation of the parasite and of the evolution of Chagas disease. The nuclear receptors known as peroxisome proliferator-activated receptors (PPARs) have emerged as key regulators of lipid metabolism and inflammation. The precise role of PPAR ligands in T. cruzi infection or in Chagas disease is poorly understood. This review summarizes our knowledge about T. cruzi infection as well as about the activation of PPARs and the potential role of their ligands in the resolution of inflammation, with the aim to address a new pharmacological approach to improve the host health.
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85
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Activation of peroxisome proliferator-activated receptor-gamma by glitazones reduces the expression and release of monocyte chemoattractant protein-1 in human mesothelial cells. Mediators Inflamm 2012; 2012:217696. [PMID: 22496599 PMCID: PMC3306974 DOI: 10.1155/2012/217696] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 10/30/2011] [Indexed: 11/21/2022] Open
Abstract
Human peritoneal mesothelial cells (MC) play an important role in inflammatory processes of the peritoneal cavity by producing various cytokines and chemokines, such as monocyte chemoattractant protein-1 (MCP-1). The present study was designed to assess the effect of the peroxisome proliferator-activated receptor-gamma- (PPARγ-) activator rosiglitazone on the mesothelial MCP-1 expression and release. Primary cultures of MC were obtained from omental tissue. MCP-1 antigen concentrations were measured in the cell supernatant by ELISA and MCP-1 mRNA levels by real-time polymerase chain reaction. The presence of PPARγ on MC was assayed in a Western Blot analysis. MC constitutively express PPARγ. Activation of this receptor via rosiglitazone (0,1–10 μmol/L) resulted in significantly reduced amounts of mesothelial MCP-1 release as well as MCP-1 mRNA. The use of the PPARγ inhibitor GW-9662 could completely prevent the rosiglitazone effects. Rosiglitazone was also effective in reducing TNFα-induced enhanced secretion of MCP-1. Our findings indicate that glitazones are effective in reducing constitutive and TNFα-stimulated mesothelial MCP-1 mRNA expression and release.
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86
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Harmon GS, Lam MT, Glass CK. PPARs and lipid ligands in inflammation and metabolism. Chem Rev 2012; 111:6321-40. [PMID: 21988241 DOI: 10.1021/cr2001355] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Gregory S Harmon
- Department of Medicine, Division of Digestive Diseases, University of California-Los Angeles, Los Angeles, California 90095, USA
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87
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Salvadó L, Serrano-Marco L, Barroso E, Palomer X, Vázquez-Carrera M. Targeting PPARβ/δ for the treatment of type 2 diabetes mellitus. Expert Opin Ther Targets 2012; 16:209-23. [DOI: 10.1517/14728222.2012.658370] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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88
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Gurevich I, Zhang C, Encarnacao PC, Struzynski CP, Livings SE, Aneskievich BJ. PPARγ and NF-κB regulate the gene promoter activity of their shared repressor, TNIP1. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1819:1-15. [PMID: 22001530 PMCID: PMC3249470 DOI: 10.1016/j.bbagrm.2011.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 09/27/2011] [Accepted: 09/30/2011] [Indexed: 11/27/2022]
Abstract
Human TNFAIP3 interacting protein 1 (TNIP1) has diverse functions including support of HIV replication through its interaction with viral Nef and matrix proteins, reduction of TNFα-induced signaling through its interaction with NF-κB pathway proteins, and corepression of agonist-bound retinoic acid receptors and peroxisome proliferator-activated receptors (PPAR). The wide tissue distribution of TNIP1 provides the opportunity to influence numerous cellular responses in these roles and defining control of TNIP1 expression would be central to improved understanding of its impact on cell function. We cloned 6kb of the human TNIP1 promoter and performed predictive and functional analyses to identify regulatory elements. The promoter region proximal to the transcription start site is GC-rich without a recognizable TATA box. In contrast to this proximal ~500bp region, 6kb of the promoter increased reporter construct constitutive activity over five-fold. Throughout the 6kb length, in silico analysis identified several potential binding sites for both constitutive and inducible transcription factors; among the latter were candidate NF-κB binding sequences and peroxisome proliferator response elements (PPREs). We tested NF-κB and PPAR regulation of the endogenous TNIP1 gene and cloned promoter by expression studies, electrophoretic mobility shift assays, and chromatin immunoprecipitations. We validated NF-κB sites in the TNIP1 promoter proximal and distal regions as well as one PPRE in the distal region. The ultimate control of the TNIP1 promoter is likely to be a combination of constitutive transcription factors and those subject to activation such as NF-κB and PPAR.
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Affiliation(s)
- Igor Gurevich
- Graduate Program in Pharmacology & Toxicology, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Carmen Zhang
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Priscilla C. Encarnacao
- Graduate Program in Pharmacology & Toxicology, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Charles P. Struzynski
- Doctor of Pharmacy Program, School of Pharmacy, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Sarah E. Livings
- Doctor of Pharmacy Program, School of Pharmacy, University of Connecticut, Storrs, CT 06269-3092; USA
| | - Brian J. Aneskievich
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269-3092; USA
- Center for Regenerative Biology, University of Connecticut, Storrs, CT 06269-3092; USA
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89
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Saglam F, Cavdar Z, Sarioglu S, Kolatan E, Oktay G, Yilmaz O, Camsari T. Pioglitazone reduces peritoneal fibrosis via inhibition of TGF-β, MMP-2, and MMP-9 in a model of encapsulating peritoneal sclerosis. Ren Fail 2011; 34:95-102. [PMID: 22136281 DOI: 10.3109/0886022x.2011.623498] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE Matrix metalloproteinases (MMPs) and transforming growth factor beta (TGF-β) were increased in peritoneal dialysis patients with encapsulating peritoneal sclerosis (EPS) and in chlorhexidine gluconate (CG)-induced peritoneal sclerosing animal models. Peroxisome proliferator-activated receptors (PPARs) are the major regulators of key metabolic pathways of various inflammatory responses in fibrosing processes in most tissues. The objective of this study was to investigate the effect of pioglitazone (Pio), a synthetic PPAR-γ ligand, on the development of peritoneal fibrosis in CG-induced EPS rats. METHODS Thirty-two Wistar albino rats were intraperitoneally injected with saline (C group n = 8) or with CG (1.5 mL/100 g; CG group, n = 8). Pio (30 mg/kg/day) was administered orally to another group of CG injected rats (the CG + Pio group, n = 8) and to another control group (Pio group, n = 8) from initiation to the end of this study. After 14 days of Pio administration, the rats were killed and the parietal and visceral peritoneum were harvested. TGF-β, MMP-2, MMP-9, tissue inhibitor of metalloproteinases (TIMP)-1, and TIMP-2 activity assays and a morphological examination of the peritoneal tissues were performed. RESULTS Pio significantly inhibited thickening of the submesothelial layer, fibrosis, and inflammation in the peritoneum. It also prevented increases in pro-MMP-2, pro-MMP-9, TIMP-1, and TGF-β activities. CONCLUSION Pio, via MMP and TGF-β inhibition, may lessen accumulation of peritoneal extracellular matrix and fibrosis to some extent in an EPS model and might be a new approach to the amelioration of EPS.
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Affiliation(s)
- Funda Saglam
- Department of Nephrology, School of Medicine, Dokuz Eylul University, Izmir, Balcova, Turkey.
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90
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Abstract
DLK (dual leucine zipper-bearing kinase) is a key regulator of development, cell differentiation and apoptosis. Interestingly, recent studies have shown that DLK expression is up-regulated in 3T3-L1 cells induced to differentiate into adipocytes and that DLK knockdown impairs the expression of PPARγ (peroxisome-proliferator-activated receptor γ), a master regulator of adipogenesis. Because the PPARγ agonist rosiglitazone was found to increase DLK expression in 3T3-L1 cells, we hypothesized that PPARγ is required for the transcriptional activation of the DLK gene. To test this hypothesis, we first examined the effects of pharmacological inhibition or shRNA (small-hairpin RNA)-mediated depletion of PPARγ on DLK accumulation in 3T3-L1 cells undergoing differentiation. In addition to blocking adipocyte conversion of 3T3-L1 cells, inhibition of PPARγ suppressed DLK expression at both the mRNA and protein levels. Moreover, supporting a role for PPARγ in DLK regulation, two potential PPARγ-binding sites identified by bioinformatic tools at positions -611 and -767 upstream of the DLK gene transcriptional start site were shown by electrophoretic mobility-shift assay and chromatin immunoprecipitation to bind PPARγ and its essential heterodimer partner retinoid X receptor as differentiation proceeds. Collectively, these results show that DLK is a novel transcriptional target of PPARγ with functional PPARγ-binding sites in its promoter.
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91
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Nuclear receptor signaling inhibits HIV-1 replication in macrophages through multiple trans-repression mechanisms. J Virol 2011; 85:10834-50. [PMID: 21849441 DOI: 10.1128/jvi.00789-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Sexually transmitted pathogens activate HIV-1 replication and inflammatory gene expression in macrophages through engagement of Toll-like receptors (TLRs). Ligand-activated nuclear receptor (NR) transcription factors, including glucocorticoid receptor (GR), peroxisome proliferator-activated receptor gamma (PPARγ), and liver X receptor (LXR), are potent inhibitors of TLR-induced inflammatory gene expression. We therefore hypothesized that ligand-activated NRs repress both basal and pathogen-enhanced HIV-1 replication in macrophages by directly repressing HIV-1 transcription and by ameliorating the local proinflammatory response to pathogens. We show that the TLR2 ligand PAM3CSK4 activated virus transcription in macrophages and that NR signaling repressed both basal and TLR-induced HIV-1 transcription. NR ligand treatment repressed HIV-1 expression when added concurrently with TLR ligands and in the presence of cycloheximide, demonstrating that they act independently of new cellular gene expression. We found that treatment with NR ligands inhibited the association of AP-1 and NF-κB subunits, as well as the coactivator CBP, with the long terminal repeat (LTR). We show for the first time that the nuclear corepressor NCoR is bound to HIV-1 LTR in unstimulated macrophages and is released from the LTR after TLR engagement. Treatment with PPARγ and LXR ligands, but not GR ligands, prevented this TLR-induced clearance of NCoR from the LTR. Our data demonstrate that both classical and nonclassical trans-repression mechanisms account for NR-mediated HIV-1 repression. Finally, NR ligand treatment inhibited the potent proinflammatory response induced by PAM3CSK4 that would otherwise activate HIV-1 expression in infected cells. Our findings provide a rationale for studying ligand-activated NRs as modulators of basal and inflammation-induced HIV-1 replication.
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Peroxisome Proliferator-Activated Receptor-gamma in Amyotrophic Lateral Sclerosis and Huntington's Disease. PPAR Res 2011; 2008:418765. [PMID: 18464922 PMCID: PMC2366134 DOI: 10.1155/2008/418765] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Accepted: 02/19/2008] [Indexed: 01/26/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a debilitating and one of the most common adult-onset neurodegenerative diseases with the prevalence of about 5 per 100 000 individuals. It results in the progressive loss of upper and lower motor neurons and leads to gradual muscle weakening ultimately causing paralysis and death. ALS has an obscure cause and currently no effective treatment exists. In this review, a potentially important pathway is described that can be activated by peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists and has the ability to block the neuropathological damage caused by inflammation in ALS and possibly in other neudegenerative diseases like Huntington's disease (HD). Neuroinflammation is a common pathological feature in neurodegenerative diseases. Therefore, PPAR-gamma agonists are thought to be neuroprotective in ALS and HD. We and others have tested the neuroprotective effect of pioglitazone (Actos), a PPAR-gamma agonist, in G93A SOD1 transgenic mouse model of ALS and found significant increase in survival of G93A SOD1 mice. These findings suggest that PPAR-gamma may be an important regulator of neuroinflammation and possibly a new target for the development of therapeutic strategies for ALS. The involvement of PPAR-gamma in HD is currently under investigation, one study finds that the treatment with rosiglitazone had no protection in R6/2 transgenic mouse model of HD. PPAR-gamma coactivator-1alpha (PGC-1alpha) is a transcriptional coactivator that works together with combination of other transcription factors like PPAR-gamma in the regulation of mitochondrial biogenesis. Therefore, PPAR-gamma is a possible target for ALS and HD as it functions as transcription factor that interacts with PGC-1alpha. In this review, the role of PPAR-gamma in ALS and HD is discussed based on the current literature and hypotheses.
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93
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PPAR-gamma: Therapeutic Potential for Multiple Sclerosis. PPAR Res 2011; 2008:627463. [PMID: 18604287 PMCID: PMC2441778 DOI: 10.1155/2008/627463] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Accepted: 06/02/2008] [Indexed: 01/04/2023] Open
Abstract
The role of peroxisome proliferator-activated receptors (PPARs) in altering lipid and glucose metabolism is well established. More recent studies indicate that PPARs also play critical roles in controlling immune responses. We and others have previously demonstrated that PPAR-γ agonists modulate the development of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). This review will discuss the cellular and molecular mechanisms by which these agonists are believed to modulate disease. The therapeutic potential of PPAR-γ agonists in the treatment of multiple sclerosis will also be considered.
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Abstract
Mononuclear phagocytes often function as control switches of the immune system, securing the balance between pro- and anti-inflammatory reactions. For this purpose and depending on the activating stimuli, these cells can develop into different subsets: proinflammatory classically activated (M1) or anti-inflammatory alternatively activated (M2) macrophages. The expression of the nuclear peroxisome proliferator-activated receptors (PPARs) is regulated by M1- or M2-inducing stimuli, and these receptors are generally considered to counteract inflammatory M1 macrophages, while actively promoting M2 activation. This is of importance in a tumor context, where M1 are important initiators of inflammation-driven cancers. As a consequence, PPAR agonists are potentially usefull for inhibiting the early phases of tumorigenesis through their antagonistic effect on M1. In more established tumors, the macrophage phenotype is more diverse, making it more difficult to predict the outcome of PPAR agonism. Overall, in our view current knowledge provides a sound basis for the clinical evaluation of PPAR ligands as chemopreventive agents in chronic inflammation-associated cancer development, while cautioning against the unthoughtful application of these agents as cancer therapeutics.
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95
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Mandrekar-Colucci S, Landreth GE. Nuclear receptors as therapeutic targets for Alzheimer's disease. Expert Opin Ther Targets 2011; 15:1085-97. [PMID: 21718217 DOI: 10.1517/14728222.2011.594043] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION Alzheimer's disease (AD) is characterized by the accumulation and extensive deposition of amyloid β (Aβ) in the parenchyma of the brain. This accumulation of amyloid is associated with perturbations in synaptic function, impairments in energy metabolism and induction of a chronic inflammatory response which acts to promote neuronal loss and cognitive impairment. AREAS COVERED Currently, there are no drugs that target the underlying mechanisms of AD. Here, we propose a class of nuclear receptors as novel and promising new therapeutic targets for AD. This review summarizes the literature on nuclear receptors and their effects on AD-related pathophysiology. EXPERT OPINION Nuclear receptors are attractive targets for the treatment of AD due to their ability to facilitate degradation of Aβ, affect microglial activation and suppress the inflammatory milieu of the brain. Liver X receptor agonists have proven difficult to move into clinical trials as long-term treatment results in hepatic steatosis. It is our view that PPAR-γ activation remains a promising avenue for the treatment for AD; however, the poor BBB permeability of the currently available agonists and the negative outcome of the Phase III clinical trials are likely to diminish interest in pursuing this target.
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Affiliation(s)
- Shweta Mandrekar-Colucci
- Case Western Reserve University School of Medicine, Department of Neurosciences, Alzheimer Research Laboratory, Cleveland, OH 44106, USA
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96
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Serghides L. The Case for the Use of PPARγ Agonists as an Adjunctive Therapy for Cerebral Malaria. PPAR Res 2011; 2012:513865. [PMID: 21772838 PMCID: PMC3135089 DOI: 10.1155/2012/513865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Accepted: 02/28/2011] [Indexed: 12/24/2022] Open
Abstract
Cerebral malaria is a severe complication of Plasmodium falciparum infection associated with high mortality even when highly effective antiparasitic therapy is used. Adjunctive therapies that modify the pathophysiological processes caused by malaria are a possible way to improve outcome. This review focuses on the utility of PPARγ agonists as an adjunctive therapy for the treatment of cerebral malaria. The current knowledge of PPARγ agonist use in malaria is summarized. Findings from experimental CNS injury and disease models that demonstrate the potential for PPARγ agonists as an adjunctive therapy for cerebral malaria are also discussed.
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Affiliation(s)
- Lena Serghides
- Sandra A. Rotman Laboratories, McLaughlin-Rotman Centre for Global Health, Toronto General Hospital, University Health Network, 101 College Street, Suite 10-359, Toronto, ON, Canada M5G 1L7
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97
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Kane CJ, Phelan KD, Han L, Smith RR, Xie J, Douglas JC, Drew PD. Protection of neurons and microglia against ethanol in a mouse model of fetal alcohol spectrum disorders by peroxisome proliferator-activated receptor-γ agonists. Brain Behav Immun 2011; 25 Suppl 1:S137-45. [PMID: 21376806 PMCID: PMC3104506 DOI: 10.1016/j.bbi.2011.02.016] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 02/25/2011] [Accepted: 02/27/2011] [Indexed: 02/05/2023] Open
Abstract
Fetal alcohol spectrum disorders (FASD) result from ethanol exposure to the developing fetus and are the most common cause of mental retardation in the United States. These disorders are characterized by a variety of neurodevelopmental and neurodegenerative anomalies which result in significant lifetime disabilities. Thus, novel therapies are required to limit the devastating consequences of FASD. Neuropathology associated with FASD can occur throughout the central nervous system (CNS), but is particularly well characterized in the developing cerebellum. Rodent models of FASD have previously demonstrated that both Purkinje cells and granule cells, which are the two major types of neurons in the cerebellum, are highly susceptible to the toxic effects of ethanol. The current studies demonstrate that ethanol decreases the viability of cultured cerebellar granule cells and microglial cells. Interestingly, microglia have dual functionality in the CNS. They provide trophic and protective support to neurons. However, they may also become pathologically activated and produce inflammatory molecules toxic to parenchymal cells including neurons. The findings in this study demonstrate that the peroxisome proliferator-activated receptor-γ agonists 15-deoxy-Δ12,15 prostaglandin J2 and pioglitazone protect cultured granule cells and microglia from the toxic effects of ethanol. Furthermore, investigations using a newly developed mouse model of FASD and stereological cell counting methods in the cerebellum elucidate that ethanol administration to neonates is toxic to both Purkinje cell neurons as well as microglia, and that in vivo administration of PPAR-γ agonists protects these cells. In composite, these studies suggest that PPAR-γ agonists may be effective in limiting ethanol-induced toxicity to the developing CNS.
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98
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Li N, Salter RC, Ramji DP. Molecular mechanisms underlying the inhibition of IFN-γ-induced, STAT1-mediated gene transcription in human macrophages by simvastatin and agonists of PPARs and LXRs. J Cell Biochem 2011; 112:675-83. [PMID: 21268089 DOI: 10.1002/jcb.22976] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PPARs and LXRs are ligand-activated transcription factors that are emerging as promising therapeutic targets for limiting atherosclerosis, an inflammatory disorder orchestrated by cytokines. The potent anti-atherogenic actions of these nuclear receptors involve the regulation of glucose and lipid metabolism along with attenuation of the inflammatory response. Similarly, cholesterol-lowering drugs, statins, inhibit inflammation. Unfortunately, the mechanisms underlying such inhibitory actions of these agents in human macrophages are poorly understood and were therefore investigated in relation to IFN-γ, a key pro-atherogenic cytokine, which mediates its cellular effects mainly through STAT1. Simvastatin and PPAR agonists had no effect on the IFN-γ-induced, phosphorylation-mediated activation of STAT1 and its DNA binding but attenuated its ability to activate gene transcription. On the other hand, LXR activators attenuated both DNA binding and trans-activation potential of STAT1 induced by IFN-γ. These studies reveal differences in the mechanism of action of agonists of PPARs (and simvastatin) and LXRs on the IFN-γ-induced, STAT1-mediated gene transcription in human macrophages.
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Affiliation(s)
- Na Li
- Cardiff School of Biosciences, Cardiff University, Cardiff, UK
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Soskić SS, Dobutović BD, Sudar EM, Obradović MM, Nikolić DM, Zarić BL, Stojanović SD, Stokić EJ, Mikhailidis DP, Isenović ER. Peroxisome proliferator-activated receptors and atherosclerosis. Angiology 2011; 62:523-34. [PMID: 21467121 DOI: 10.1177/0003319711401012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The peroxisome proliferator-activated receptors (PPARs) represent the family of 3 nuclear receptor isoforms-PPARα, -γ, and -δ/β, which are encoded by different genes. As lipid sensors, they are primarily involved in regulation of lipid metabolism and subsequently in inflammation and atherosclerosis. Atherosclerosis considers accumulation of the cells and extracellular matrix in the vessel wall leading to the formation of atherosclerotic plaque, atherothrombosis, and other vascular complications. Besides existence of natural ligands for PPARs, their more potent synthetic ligands are fibrates and thiazolidindiones. Future investigations should now focus on the mechanisms of PPARs activation, which might present new approaches involved in the antiatherosclerotic effects revealed in this review. In addition, in this review we are presenting latest data from recent performed clinical studies which have focus on novel approach to PPARs agonists as potential therapeutic agents in the treatment of complex disease such as atherosclerosis.
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Affiliation(s)
- Sanja S Soskić
- Laboratory for Radiobiology and Molecular Genetics, Institute Vinca, University of Belgrade, Belgrade, Serbia
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Xu P, Xu K, Wang J, Jiang JP, Chen LQ. Pioglitazone: a promising therapeutic tool in sodium taurocholate-induced severe acute pancreatitis. Dig Dis Sci 2011; 56:1082-9. [PMID: 20824499 DOI: 10.1007/s10620-010-1393-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Accepted: 08/11/2010] [Indexed: 12/12/2022]
Abstract
BACKGROUND Studies suggest that peroxisome proliferator-activated receptor γ(PPARγ) ligands may represent a therapeutic option in acute pancreatitis, yet most of them have been prophylactic administrated. AIMS To evaluate the therapeutic effect of pioglitazone in rats with severe acute pancreatitis induced by sodium taurocholate. METHODS Severe acute pancreatitis (SAP) was induced in male Sprague-Dawley rats by the retrograde injection of 5% sodium taurocholate into the pancreatic duct. After SAP was induced, pioglitazone was injected intraperitoneally and its role on the severity of inflammatory response and pancreatic injury was investigated. Amylase activity, inflammatory cytokines production, pathological changes of pancreas, PPARγ mRNA expression, and the survival rate were examined. RESULTS Treatment with pioglitazone decreased the level of amylase activity, proinflammatory factors IL-6 and TNF-α, ameliorated pancreatic histological score, and upregulated the expression of PPARγ mRNA. The survival rate in the early stage of severe acute pancreatitis was also improved. CONCLUSIONS Pioglitazone can be used as a therapeutic drug and relieve the damages caused by SAP, which suggests PPARγ ligand-pioglitazone offers a potent approach for the treatment of severe acute pancreatitis.
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Affiliation(s)
- Ping Xu
- Department of Gastroenterology, Branch Hospital of the First People's Hospital, Shanghai Jiao Tong University, School of Medicine, 201600, Shanghai, China.
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