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Goerdeler C, Engelmann B, Aldehoff AS, Schaffert A, Blüher M, Heiker JT, Wabitsch M, Schubert K, Rolle-Kampczyk U, von Bergen M. Metabolomics in human SGBS cells as new approach method for studying adipogenic effects: Analysis of the effects of DINCH and MINCH on central carbon metabolism. ENVIRONMENTAL RESEARCH 2024; 252:118847. [PMID: 38582427 DOI: 10.1016/j.envres.2024.118847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 03/20/2024] [Accepted: 03/31/2024] [Indexed: 04/08/2024]
Abstract
Growing evidence suggests that exposure to certain metabolism-disrupting chemicals (MDCs), such as the phthalate plasticizer DEHP, might promote obesity in humans, contributing to the spread of this global health problem. Due to the restriction on the use of phthalates, there has been a shift to safer declared substitutes, including the plasticizer diisononyl-cyclohexane-1,2-dicarboxylate (DINCH). Notwithstanding, recent studies suggest that the primary metabolite monoisononyl-cyclohexane-1,2-dicarboxylic acid ester (MINCH), induces differentiation of human adipocytes and affects enzyme levels of key metabolic pathways. Given the lack of methods for assessing metabolism-disrupting effects of chemicals on adipose tissue, we used metabolomics to analyze human SGSB cells exposed to DINCH or MINCH. Concentration analysis of DINCH and MINCH revealed that uptake of MINCH in preadipocytes was associated with increased lipid accumulation during adipogenesis. Although we also observed intracellular uptake for DINCH, the solubility of DINCH in cell culture medium was limited, hampering the analysis of possible effects in the μM concentration range. Metabolomics revealed that MINCH induces lipid accumulation similar to peroxisome proliferator-activated receptor gamma (PPARG)-agonist rosiglitazone through upregulation of the pyruvate cycle, which was recently identified as a key driver of de novo lipogenesis. Analysis of the metabolome in the presence of the PPARG-inhibitor GW9662 indicated that the effect of MINCH on metabolism was mediated at least partly by a PPARG-independent mechanism. However, all effects of MINCH were only observed at high concentrations of 10 μM, which are three orders of magnitudes higher than the current concentrations of plasticizers in human serum. Overall, the assessment of the effects of DINCH and MINCH on SGBS cells by metabolomics revealed no adipogenic potential at physiologically relevant concentrations. This finding aligns with previous in vivo studies and supports the potential of our method as a New Approach Method (NAM) for the assessment of adipogenic effects of environmental chemicals.
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Affiliation(s)
- Cornelius Goerdeler
- Department of Molecular Toxicology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany.
| | - Beatrice Engelmann
- Department of Molecular Toxicology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany.
| | - Alix Sarah Aldehoff
- Department of Molecular Toxicology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany.
| | - Alexandra Schaffert
- Department of Molecular Toxicology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany.
| | - Matthias Blüher
- Department of Endocrinology, Nephrology and Rheumatology, Faculty of Medicine, University of Leipzig, Leipzig, Germany; Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany.
| | - John T Heiker
- Helmholtz Institute for Metabolic, Obesity and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Leipzig, Germany.
| | - Martin Wabitsch
- Division of Pediatric Endocrinology and Diabetes, Ulm University Medical Center, Ulm, Germany.
| | - Kristin Schubert
- Department of Molecular Toxicology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany.
| | - Ulrike Rolle-Kampczyk
- Department of Molecular Toxicology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany.
| | - Martin von Bergen
- Department of Molecular Toxicology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany; Institute of Biochemistry, Leipzig University, Leipzig, Germany; German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.
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Ahmad M, Abramovich I, Agranovich B, Nemirovski A, Gottlieb E, Hinden L, Tam J. Kidney Proximal Tubule GLUT2-More than Meets the Eye. Cells 2022; 12:cells12010094. [PMID: 36611887 PMCID: PMC9818791 DOI: 10.3390/cells12010094] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/06/2022] [Accepted: 12/23/2022] [Indexed: 12/28/2022] Open
Abstract
Tubulopathy plays a central role in the pathophysiology of diabetic kidney disease (DKD). Under diabetic conditions, the kidney proximal tubule cells (KPTCs) are exposed to an extensive amount of nutrients, most notably glucose; these nutrients deteriorate KPTCs function and promote the development and progression of DKD. Recently, the facilitative glucose transporter 2 (GLUT2) in KPTCs has emerged as a central regulator in the pathogenesis of DKD. This has been demonstrated by identifying its specific role in enhancing glucose reabsorption and glucotoxicity, and by deciphering its effect in regulating the expression of the sodium-glucose transporter 2 (SGLT2) in KPTCs. Moreover, reduction/deletion of KPTC-GLUT2 has been recently found to ameliorate DKD, raising the plausible idea of considering it as a therapeutic target against DKD. However, the underlying molecular mechanisms by which GLUT2 exerts its deleterious effects in KPTCs remain vague. Herein, we review the current findings on the proximal tubule GLUT2 biology and function under physiologic conditions, and its involvement in the pathophysiology of DKD. Furthermore, we shed new light on its cellular regulation during diabetic conditions.
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Affiliation(s)
- Majdoleen Ahmad
- Obesity and Metabolism Laboratory, Faculty of Medicine, The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Ifat Abramovich
- Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 3525422, Israel
| | - Bella Agranovich
- Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 3525422, Israel
| | - Alina Nemirovski
- Obesity and Metabolism Laboratory, Faculty of Medicine, The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
| | - Eyal Gottlieb
- Rappaport Faculty of Medicine and Research Institute, Technion, Haifa 3525422, Israel
| | - Liad Hinden
- Obesity and Metabolism Laboratory, Faculty of Medicine, The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
- Correspondence: (L.H.); (J.T.); Tel.: +972-2-675-7650 (L.H.); +972-2-675-7645 (J.T.)
| | - Joseph Tam
- Obesity and Metabolism Laboratory, Faculty of Medicine, The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem 9112001, Israel
- Correspondence: (L.H.); (J.T.); Tel.: +972-2-675-7650 (L.H.); +972-2-675-7645 (J.T.)
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Sharma R, Tiwari S. Renal gluconeogenesis in insulin resistance: A culprit for hyperglycemia in diabetes. World J Diabetes 2021; 12:556-568. [PMID: 33995844 PMCID: PMC8107972 DOI: 10.4239/wjd.v12.i5.556] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/27/2021] [Accepted: 04/23/2021] [Indexed: 02/06/2023] Open
Abstract
Renal gluconeogenesis is one of the major pathways for endogenous glucose production. Impairment in this process may contribute to hyperglycemia in cases with insulin resistance and diabetes. We reviewed pertinent studies to elucidate the role of renal gluconeogenesis regulation in insulin resistance and diabetes. A consensus on the suppressive effect of insulin on kidney gluconeogenesis has started to build up. Insulin-resistant models exhibit reduced insulin receptor (IR) expression and/or post-receptor signaling in their kidney tissue. Reduced IR expression or post-receptor signaling can cause impairment in insulin’s action on kidneys, which may increase renal gluconeogenesis in the state of insulin resistance. It is now established that the kidney contributes up to 20% of all glucose production via gluconeogenesis in the post-absorptive phase. However, the rate of renal glucose release excessively increases in diabetes. The rise in renal glucose release in diabetes may contribute to fasting hyperglycemia and increased postprandial glucose levels. Enhanced glucose release by the kidneys and renal expression of the gluconeogenic-enzyme in diabetic rodents and humans further point towards the significance of renal gluconeogenesis. Overall, the available literature suggests that impairment in renal gluconeogenesis in an insulin-resistant state may contribute to hyperglycemia in type 2 diabetes.
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Affiliation(s)
- Rajni Sharma
- Department of Molecular Medicine and Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, India
| | - Swasti Tiwari
- Department of Molecular Medicine and Biotechnology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, India
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PPAR γ and Its Agonists in Chronic Kidney Disease. Int J Nephrol 2020; 2020:2917474. [PMID: 32158560 PMCID: PMC7060840 DOI: 10.1155/2020/2917474] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 01/11/2020] [Accepted: 02/03/2020] [Indexed: 02/06/2023] Open
Abstract
Chronic kidney disease (CKD) has become a global healthcare issue. CKD can progress to irreversible end-stage renal diseases (ESRD) or renal failure. The major risk factors for CKD include obesity, diabetes, and cardiovascular diseases. Understanding the key process involved in the disease development may lead to novel interventive strategies, which is currently lagging behind. Peroxisome proliferator-activated receptor γ (PPARγ) is one of the ligand-activated transcription factor superfamily members and is globally expressed in human tissues. Its agonists such as thiazolidinediones (TZDs) have been applied as effective antidiabetic drugs as they control insulin sensitivity in multiple metabolic tissues. Besides, TZDs exert protective effects in multiple other CKD risk disease contexts. As PPARγ is abundantly expressed in major kidney cells, its physiological roles in those cells have been studied in both cell and animal models. The function of PPARγ in the kidney ranges from energy metabolism, cell proliferation to inflammatory suppression, although major renal side effects of existing agonists (including TZDs) have been reported, which limited their application in treating CKD. In the current review, we systemically assess the function of PPARγ in CKDs and the benefits and current limitations of its agonists in the clinical applications.
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Chai BK, Al-Shagga M, Pan Y, Then SM, Ting KN, Loh HS, Mohankumar SK. Cis-9, Trans-11 Conjugated Linoleic Acid Reduces Phosphoenolpyruvate Carboxykinase Expression and Hepatic Glucose Production in HepG2 Cells. Lipids 2019; 54:369-379. [PMID: 31124166 DOI: 10.1002/lipd.12154] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 04/23/2019] [Accepted: 04/24/2019] [Indexed: 11/08/2022]
Abstract
Dysregulated hepatic gluconeogenesis is a hallmark of insulin resistance and type 2 diabetes mellitus (T2DM). Although existing drugs have been proven to improve gluconeogenesis, achieving this objective with functional food is of interest, especially using conjugated linoleic acid (CLA) found in dairy products. Both cis-9, trans-11 (c9,t11) and trans-10, cis-12 (t10,c12) isomers of CLA were tested in human (HepG2) and rat (H4IIE) hepatocytes for their potential effects on gluconeogenesis. The hepatocytes exposed for 24 h with 20 μM of c9,t11-CLA had attenuated the gluconeogenesis in both HepG2 and H4IIE by 62.5% and 80.1%, respectively. In contrast, t10,c12-CLA had no effect. Of note, in HepG2 cells, the exposure of c9,t11-CLA decreased the transcription of gluconeogenic enzymes, cytosolic phosphoenolpyruvate carboxykinase (PCK1) by 87.7%, and glucose-6-phosphatase catalytic subunit (G6PC) by 38.0%, while t10,c12-CLA increased the expression of G6PC, suggesting the isomer-specific effects of CLA on hepatic glucose production. In HepG2, the peroxisome proliferator-activated receptor (PPAR) agonist, rosiglitazone, reduced the glucose production by 72.9%. However, co-administration of c9,t11-CLA and rosiglitazone neither exacerbated nor attenuated the efficacy of rosiglitazone to inhibit glucose production; meanwhile, t10,c12-CLA abrogated the efficacy of rosiglitazone. Paradoxically, PPARγ antagonist GW 9662 also led to 70.2% reduction of glucose production and near undetectable PCK1 expression by abrogating CLA actions. Together, while the precise mechanisms by which CLA isomers modulate hepatic gluconeogenesis directly or via PPAR warrant further investigation, our findings establish that c9,t11-CLA suppresses gluconeogenesis by decreasing PEPCK on hepatocytes.
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Affiliation(s)
- Boon Kheng Chai
- Department of Biomedical Sciences, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia
| | - Mustafa Al-Shagga
- Department of Biomedical Sciences, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia
| | - Yan Pan
- Department of Biomedical Sciences, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia
| | - Sue-Mian Then
- Department of Biomedical Sciences, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia
| | - Kang Nee Ting
- Department of Biomedical Sciences, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia
| | - Hwei-San Loh
- School of Biosciences, Faculty of Science, University of Nottingham Malaysia Campus, Jalan Broga, 43500, Semenyih, Selangor Darul Ehsan, Malaysia
| | - Suresh K Mohankumar
- TIFAC CORE in Herbal Drugs, Department of Pharmacognosy, JSS College of Pharmacy (Ooty), JSS Academy of Higher Education & Research, Rocklands, Udhagamandalam, 643001, Tamil Nadu, India
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Corrales P, Izquierdo-Lahuerta A, Medina-Gómez G. Maintenance of Kidney Metabolic Homeostasis by PPAR Gamma. Int J Mol Sci 2018; 19:ijms19072063. [PMID: 30012954 PMCID: PMC6073436 DOI: 10.3390/ijms19072063] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 07/11/2018] [Indexed: 01/12/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are a family of nuclear hormone receptors that control the transcription of specific genes by binding to regulatory DNA sequences. Among the three subtypes of PPARs, PPARγ modulates a broad range of physiopathological processes, including lipid metabolism, insulin sensitization, cellular differentiation, and cancer. Although predominantly expressed in adipose tissue, PPARγ expression is also found in different regions of the kidney and, upon activation, can redirect metabolism. Recent studies have highlighted important roles for PPARγ in kidney metabolism, such as lipid and glucose metabolism and renal mineral control. PPARγ is also implicated in the renin-angiotensin-aldosterone system and, consequently, in the control of systemic blood pressure. Accordingly, synthetic agonists of PPARγ have reno-protective effects both in diabetic and nondiabetic patients. This review focuses on the role of PPARγ in renal metabolism as a likely key factor in the maintenance of systemic homeostasis.
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Affiliation(s)
- Patricia Corrales
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos. Avda. de Atenas s/n. Alcorcón, 28922 Madrid, Spain.
| | - Adriana Izquierdo-Lahuerta
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos. Avda. de Atenas s/n. Alcorcón, 28922 Madrid, Spain.
| | - Gema Medina-Gómez
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos. Avda. de Atenas s/n. Alcorcón, 28922 Madrid, Spain.
- MEMORISM Research Unit of University Rey Juan Carlos-Institute of Biomedical Research "Alberto Sols" (CSIC), 28029 Madrid, Spain.
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7
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DHEA-induced modulation of renal gluconeogenesis, insulin sensitivity and plasma lipid profile in the control- and dexamethasone-treated rabbits. Metabolic studies. Biochimie 2016; 121:87-101. [DOI: 10.1016/j.biochi.2015.11.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 11/19/2015] [Indexed: 12/13/2022]
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Usarek M, Jagielski AK, Krempa P, Dylewska A, Kiersztan A, Drozak J, Girstun A, Derlacz RA, Bryla J. Proinsulin C-peptide potentiates the inhibitory action of insulin on glucose synthesis in primary cultured rabbit kidney-cortex tubules: Metabolic studies. Biochem Cell Biol 2014; 92:1-8. [DOI: 10.1139/bcb-2013-0074] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Effects of equimolar concentrations of proinsulin C-peptide and insulin on glucose synthesis were studied in primary cultures of rabbit kidney-cortex tubules grown in the presence of alanine, glycerol, and octanoate. The rhodamine-labeled C-peptide entered renal tubular cells and localized in nuclei, both in the presence and absence of insulin; preincubations with the unlabeled compound inhibited internalization. C-peptide did not affect glucose formation when added alone but potentiated the inhibitory action of insulin by about 20% due to a decrease in flux through glucose-6-phosphate isomerase (GPI) and (or) glucose-6-phosphatase (G6Pase). GPI inhibition was caused by: (i) increased intracellular contents of fructose-1,6-bisphosphate and fructose-1-phosphate, inhibitors of the enzyme and (ii) reduced level of the phosphorylated GPI, which exhibits higher enzymatic activity in the presence of casein kinase 2. A decrease in flux through G6Pase, due to diminished import of G6P by G6P-transporter from the cytoplasm into endoplasmic reticulum lumen, is also suggested. The data show for the first time that in the presence of insulin and C-peptide, both GPI and G6P-ase may act as regulatory enzymes of renal gluconeogenic pathway.
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Affiliation(s)
- Michal Usarek
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Adam Konrad Jagielski
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Paulina Krempa
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Anna Dylewska
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Anna Kiersztan
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Jakub Drozak
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Agnieszka Girstun
- Department of Molecular Biology, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Rafal Andrzej Derlacz
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Jadwiga Bryla
- Department of Metabolic Regulation, Institute of Biochemistry, Faculty of Biology, University of Warsaw, I. Miecznikowa 1, 02-096 Warsaw, Poland
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Sałat K, Głuch-Lutwin M, Nawieśniak B, Gawlik K, Pawlica-Gosiewska D, Witalis J, Kazek G, Filipek B, Librowski T, Więckowski K, Solnica B. Influence of analgesic active 3-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-dihydrofuran-2-one on the antioxidant status, glucose utilization and lipid accumulation in somein vitroandex vivoassays. Toxicol Mech Methods 2014; 24:204-11. [DOI: 10.3109/15376516.2013.879973] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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10
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Chen YR, Lai YL, Lin SD, Li XT, Fu YC, Xu WC. SIRT1 interacts with metabolic transcriptional factors in the pancreas of insulin-resistant and calorie-restricted rats. Mol Biol Rep 2013; 40:3373-80. [PMID: 23292098 DOI: 10.1007/s11033-012-2412-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Accepted: 12/18/2012] [Indexed: 02/05/2023]
Abstract
Sirtuin 1 (SIRT1) is one member of the silent information regulator 2 (Sir2)-like family of proteins involved in glucose homeostasis in mammals. It has been reported that SIRT1 modulates endocrine signaling of glucose and fat homeostasis by regulating transcription factors such as forkhead transcription factor 3a (FOXO3a), glucose transporter 4 (GLUT4), peroxisome proliferator-activated receptor gamma (PPARγ) and PPARγ coactivator (PGC-1α). However, it is still not clear how SIRT1 is involved in the development of insulin resistance. To determine the location and expression of SIRT1 and its target proteins in rats and analyze the interactions and functions of these proteins in insulin resistance. Forty-eight male Sprague-Dawley rats were randomly divided into four regimen groups: normal control (NC), calorie restriction (CR), high-fat (HFa), and high-fructose (HFr). Animals were fed for 12 weeks and blood samples collected from tail veins at weeks 2, 4, 6, 8 and 12 after fasting for 16 h. Baseline metabolic parameters such as fasting blood sugar, insulin, cholesterol and triglycerides were analyzed. A glucose tolerance test was carried out at the end of the study. Visceral fat, consisting of epididymis and perirenal fat, was isolated and weighed. The pancreas from each animal was also immediately removed. Immunohistochemical staining was performed to detect the locations of SIRT1, FOXO3a, GLUT4, PPARγ and PGC-1α in the β-cell of the rat pancreas. Expression in the pancreas was analyzed by western blotting. Blood biochemical analysis indicated that the HFa and HFr groups were insulin-resistant. Immunohistochemical staining showed that GLUT4 was a nuclear protein. SIRT1, FOXO3a, PPARγ and PGC-1α were present in both the nucleus and the cytoplasm of β-cells of pancreatic islets. The expression of SIRT1, GLUT4 and PGC-1α increased significantly in response to CR, but decreased in the HFr and HFa groups. FOXO3a was similar in the CR and the NC groups, whereas it declined in the HFa and HFr groups. PPARγ was elevated in the HFa group, but dropped in the CR and HFr groups. These data suggest that SIRT1 and its regulators are involved in the development of insulin resistance.
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Affiliation(s)
- Yong-Ru Chen
- Intensive Care Unit (ICU), The First Affiliated Hospital of Shantou University Medical College, Shantou 515041, China.
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Neri T, Cordazzo C, Carmazzi Y, Petrini S, Balìa C, Stefanelli F, Amoruso A, Brunelleschi S, Breschi MC, Pedrinelli R, Paggiaro P, Celi A. Effects of peroxisome proliferator-activated receptor-γ agonists on the generation of microparticles by monocytes/macrophages. Cardiovasc Res 2012; 94:537-44. [DOI: 10.1093/cvr/cvs125] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Electrophilic PPARγ Ligands Attenuate IL-1β and Silica-Induced Inflammatory Mediator Production in Human Lung Fibroblasts via a PPARγ-Independent Mechanism. PPAR Res 2011; 2011:318134. [PMID: 21765824 PMCID: PMC3135061 DOI: 10.1155/2011/318134] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Revised: 03/04/2011] [Accepted: 03/25/2011] [Indexed: 12/24/2022] Open
Abstract
Acute and chronic lung inflammation is associated with numerous important disease pathologies including asthma, chronic obstructive pulmonary disease and silicosis. Lung fibroblasts are a novel and important target of anti-inflammatory therapy, as they orchestrate, respond to, and amplify inflammatory cascades and are the key cell in the pathogenesis of lung fibrosis. Peroxisome proliferator-activated receptor gamma (PPARγ) ligands are small molecules that induce anti-inflammatory responses in a variety of tissues. Here, we report for the first time that PPARγ ligands have potent anti-inflammatory effects on human lung fibroblasts. 2-cyano-3, 12-dioxoolean-1, 9-dien-28-oic acid (CDDO) and 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) inhibit production of the inflammatory mediators interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), COX-2, and prostaglandin (PG)E2 in primary human lung fibroblasts stimulated with either IL-1β or silica. The anti-inflammatory properties of these molecules are not blocked by the PPARγ antagonist GW9662 and thus are largely PPARγ independent. However, they are dependent on the presence of an electrophilic carbon. CDDO and 15d-PGJ2, but not rosiglitazone, inhibited NF-κB activity. These results demonstrate that CDDO and 15d-PGJ2 are potent attenuators of proinflammatory responses in lung fibroblasts and suggest that these molecules should be explored as the basis for novel, targeted anti-inflammatory therapies in the lung and other organs.
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Abstract
The kidney contributes to glucose homeostasis through processes of gluconeogenesis, glucose filtration, glucose reabsorption, and glucose consumption. Each of these processes can be altered in patients with type-2 diabetes (T2DM), providing potential targets for novel therapies. Recent studies have indicated that the kidney is responsible for up to 20% of all glucose production via gluconeogenesis. In patients with T2DM, overall glucose production increases by as much as 300%, with equal contributions from hepatic and renal sources. This increased production contributes not only to increased fasting glucose in T2DM patients but also to raised postprandial glucose because, in contrast to the liver, glucose ingestion increases renal gluconeogenesis. Under normal circumstances, up to 180 g/day of glucose is filtered by the renal glomerulus and virtually all of it is subsequently reabsorbed in the proximal convoluted tubule. This reabsorption is effected by two sodium-dependent glucose cotransporter (SGLT) proteins. SGLT2, situated in the S1 segment, is a low-affinity high-capacity transporter reabsorbing up to 90% of filtered glucose. SGLT1, situated in the S3 segment, is a high-affinity low-capacity transporter reabsorbing the remaining 10%. In patients with T2DM, renal reabsorptive capacity maladaptively increases from a normal level of 19.5 to 23.3 mmol/l/min. Once glucose has been reabsorbed into the tubular epithelial cells, it diffuses into the interstitium across specific facilitative glucose transporters (GLUTs). GLUT1 and GLUT2 are associated with SGLT1 and SGLT2, respectively.
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Birnbaum Y, Long B, Qian J, Perez-Polo JR, Ye Y. Pioglitazone limits myocardial infarct size, activates Akt, and upregulates cPLA2 and COX-2 in a PPAR-γ-independent manner. Basic Res Cardiol 2011; 106:431-46. [PMID: 21360043 DOI: 10.1007/s00395-011-0162-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 02/01/2011] [Accepted: 02/04/2011] [Indexed: 12/15/2022]
Abstract
Pioglitazone (PIO), a PPAR-γ agonist, limits myocardial infarct size by activating Akt and upregulating cytosolic phospholipase A(2) (cPLA(2)) and cyclooxygenase (COX)-2. However, PIO has several PPAR-γ-independent effects. We assessed whether PIO limits myocardial infarct size in PPAR-γ-knockout mice, attenuates hypoxia-reoxygenation injury and upregulates P-Akt, cPLA(2), and COX-2 expression in PPAR-γ-knockout cardiomyocytes. Cardiac-specific inducible PPAR-γ knockout mice were generated by crossing αMHC-Cre mice to PPAR-γ(loxp/loxp) mice. PPAR-γ deletion was achieved after 7 days of intraperitoneal tamoxifen (20 mg/kg/day) administration. Mice received PIO (10 mg/kg/day), or vehicle, for 3 days and underwent coronary occlusion (30 min) followed by reperfusion (4 h). We assessed the area at risk by blue dye and infarct size by TTC. Cultured adult cardiomyocytes of PPAR-γ(loxp/loxp/cre) mice without or with pretreatment with tamoxifen were incubated with or without PIO and subjected to 2 h hypoxia/2 h reoxygenation. Cardiac-specific PPAR-γ knockout significantly increased infarct size. PIO reduced infarct size by 51% in PPAR-γ knockout mice and by 55% in mice with intact PPAR-γ. Deleting the PPAR-γ gene increased cell death in vitro. PIO reduced cell death in cells with and without intact PPAR-γ. PIO similarly increased myocardial Ser-473 P-Akt, cPLA(2), and COX-2 levels after hypoxia/reoxygenation in cells with and without intact PPAR-γ. PIO limited infarct size in mice in a PPAR-γ-independent manner. PIO activated Akt, increased the expression of cPLA(2) and COX-2, and protected adult cardiomyocytes against the effects of hypoxia/reoxygenation independent of PPAR-γ activation.
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Affiliation(s)
- Yochai Birnbaum
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, 77555, USA
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