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Hsu CN, Hsuan CF, Liao D, Chang JKJ, Chang AJW, Hee SW, Lee HL, Teng SIF. Anti-Diabetic Therapy and Heart Failure: Recent Advances in Clinical Evidence and Molecular Mechanism. Life (Basel) 2023; 13:1024. [PMID: 37109553 PMCID: PMC10144651 DOI: 10.3390/life13041024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/19/2023] [Accepted: 03/20/2023] [Indexed: 04/29/2023] Open
Abstract
Diabetic patients have a two- to four-fold increase in the risk of heart failure (HF), and the co-existence of diabetes and HF is associated with poor prognosis. In randomized clinical trials (RCTs), compelling evidence has demonstrated the beneficial effects of sodium-glucose co-transporter-2 inhibitors on HF. The mechanism includes increased glucosuria, restored tubular glomerular feedback with attenuated renin-angiotensin II-aldosterone activation, improved energy utilization, decreased sympathetic tone, improved mitochondria calcium homeostasis, enhanced autophagy, and reduced cardiac inflammation, oxidative stress, and fibrosis. The RCTs demonstrated a neutral effect of the glucagon-like peptide receptor agonist on HF despite its weight-reducing effect, probably due to it possibly increasing the heart rate via increasing cyclic adenosine monophosphate (cAMP). Observational studies supported the markedly beneficial effects of bariatric and metabolic surgery on HF despite no current supporting evidence from RCTs. Bromocriptine can be used to treat peripartum cardiomyopathy by reducing the harmful cleaved prolactin fragments during late pregnancy. Preclinical studies suggest the possible beneficial effect of imeglimin on HF through improving mitochondrial function, but further clinical evidence is needed. Although abundant preclinical and observational studies support the beneficial effects of metformin on HF, there is limited evidence from RCTs. Thiazolidinediones increase the risk of hospitalized HF through increasing renal tubular sodium reabsorption mediated via both the genomic and non-genomic action of PPARγ. RCTs suggest that dipeptidyl peptidase-4 inhibitors, including saxagliptin and possibly alogliptin, may increase the risk of hospitalized HF, probably owing to increased circulating vasoactive peptides, which impair endothelial function, activate sympathetic tones, and cause cardiac remodeling. Observational studies and RCTs have demonstrated the neutral effects of insulin, sulfonylureas, an alpha-glucosidase inhibitor, and lifestyle interventions on HF in diabetic patients.
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Affiliation(s)
- Chih-Neng Hsu
- Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital Yunlin Branch, Yunlin 640, Taiwan
| | - Chin-Feng Hsuan
- Division of Cardiology, Department of Internal Medicine, E-Da Hospital, I-Shou University, Kaohsiung 824, Taiwan
- Division of Cardiology, Department of Internal Medicine, E-Da Dachang Hospital, I-Shou University, Kaohsiung 824, Taiwan
- School of Medicine, College of Medicine, I-Shou University, Kaohsiung 840, Taiwan
| | - Daniel Liao
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Jack Keng-Jui Chang
- Biological Programs for Younger Scholar, Academia Sinica, Taipei 115, Taiwan
| | - Allen Jiun-Wei Chang
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Siow-Wey Hee
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Hsiao-Lin Lee
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Sean I. F. Teng
- Department of Cardiology, Ming-Sheng General Hospital, Taoyuan 330, Taiwan
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Subash-Babu P, Abdulaziz AlSedairy S, Abdulaziz Binobead M, Alshatwi AA. Luteolin-7-O-rutinoside Protects RIN-5F Cells from High-Glucose-Induced Toxicity, Improves Glucose Homeostasis in L6 Myotubes, and Prevents Onset of Type 2 Diabetes. Metabolites 2023; 13:metabo13020269. [PMID: 36837888 PMCID: PMC9965038 DOI: 10.3390/metabo13020269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/01/2023] [Accepted: 02/04/2023] [Indexed: 02/16/2023] Open
Abstract
Luteolin-7-O-rutinoside (lut-7-O-rutin), a flavonoid commonly present in Mentha longifolia L. and Olea europaea L. leaves has been used as a flavoring agent with some biological activity. The present study is the first attempt to analyze the protective effect of lut-7-O-rutin on high-glucose-induced toxicity to RIN-5F cells in vitro. We found that lut-7-O-rutin improved insulin secretion in both normal and high-glucose conditions in a dose-dependent manner, without toxicity observed. In addition, 20 µmol of lut-7-O-rutin improves insulin sensitization and glucose uptake significantly (p ≤ 0.01) in L6 myotubes cultured in a high-glucose medium. Lut-7-O-rutin has shown a significant (p ≤ 0.05) effect on glucose uptake in L6 myotubes compared to the reference drug, rosiglitazone (20 µmol). Gene expression analysis confirmed significantly lowered CYP1A, TNF-α, and NF-κb expressions in RIN-5F cells, and increased mitochondrial thermogenesis-related LPL, Ucp-1 and PPARγC1A mRNA expressions in L6 myotubes after 24 h of lut-7-O-rutin treatment. The levels of signaling proteins associated with intracellular glucose uptakes, such as cAMP, ChREBP-1, and AMPK, were significantly increased in L6 myotubes. In addition, the levels of the conversion rate of glucose to lactate and fatty acids were raised in insulin-stimulated conditions; the rate of glycerol conversion was found to be higher at the basal level in L6 myotubes. In conclusion, lut-7-O-rutin protects RIN-5F cells from high-glucose-induced toxicity, stimulates insulin secretion, and promotes glucose absorption and homeostasis via molecular mechanisms.
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Izmailova O, Kabaliei A, Shynkevych V, Shlykova O, Kaidashev I. PPARG agonist pioglitazone influences diurnal kidney medulla mRNA expression of core clock, inflammation-, and metabolism-related genes disrupted by reverse feeding in mice. Physiol Rep 2022; 10:e15535. [PMID: 36511486 PMCID: PMC9746034 DOI: 10.14814/phy2.15535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 06/17/2023] Open
Abstract
This study examined the influence of PPARG activation by pioglitazone (PG) on the mRNA of core clock, inflammation- and metabolism-related genes in the mouse kidney medulla as well as urinary sodium/potassium excretion rhythms disrupted by reverse feeding. Mice were assigned to daytime feeding and nighttime feeding groups. PG 20 mg/kg was administered at 7 am or 7 pm. On day 8 of the feeding intervention, mice were killed at noon and midnight. Kidney medulla expression of Arntl, Clock, Nr1d1, Cry1, Cry2, Per1, Per2, Nfe2l2, Pparg, and Scnn1g was determined by qRT PCR. We measured urinary K+ , Na+ , urine volume, food, and H2 O intake. The reverse feeding uncoupled the peripheral clock gene rhythm in mouse kidney tissues. It was accompanied by a decreased expression of Nfe2l2 and Pparg as well as an increased expression of Rela and Scnn1g. These changes in gene expressions concurred with an increase in urinary Na+ , K+ , water excretion, microcirculation disorders, and cell loss, especially in distal tubules. PG induced the restoration of diurnal core clock gene expression as well as Nfe2l2, Pparg, Scnn1g mRNA, and decreased Rela expressions, stimulating Na+ reabsorption and inhibiting K+ excretion. PG intake at 7 pm was more effective than at 7 am.
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Ehret E, Hummler E. Lessons learned about epithelial sodium channels from transgenic mouse models. Curr Opin Nephrol Hypertens 2022; 31:493-501. [PMID: 35894285 PMCID: PMC10022670 DOI: 10.1097/mnh.0000000000000821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW This review provides an up-to-date understanding about the regulation of epithelial sodium channel (ENaC) expression and function. In particular, we will focus on its implication in renal Na+ and K+ handling and control of blood pressure using transgenic animal models. RECENT FINDINGS In kidney, the highly amiloride-sensitive ENaC maintains whole body Na+ homeostasis by modulating Na+ transport via epithelia. This classical role is mostly confirmed using genetically engineered animal models. Recently identified key signaling pathways that regulate ENaC expression and function unveiled some nonclassical and unexpected channel regulatory processes. If aberrant, these dysregulated mechanisms may also result in the development of salt-dependent hypertension.The purpose of this review is to highlight the most recent findings in renal ENaC regulation and function, in considering data obtained from animal models. SUMMARY Increased ENaC-mediated Na+ transport is a prerequisite for salt-dependent forms of hypertension. To treat salt-sensitive hypertension it is crucial to fully understand the function and regulation of ENaC.
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Affiliation(s)
- Elodie Ehret
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne
| | - Edith Hummler
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne
- National Center of Competence in Research, Kidney.CH, Zurich, Switzerland
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Wu J, Lai G, Chen F, Zhang B, Zhao Y. Renal NKCC2 Is Dual Regulated by the Synergy of 20-HETE and High-Fat Diet in CYP4F2 Transgenic Mice. Kidney Blood Press Res 2021; 46:601-612. [PMID: 34320496 DOI: 10.1159/000517382] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 04/22/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION 20-Hydroxyeicosatetraenoic acid (20-HETE) is the metabolite of cytochrome P450, which modulates blood pressure by inhibiting renal sodium transport. However, the molecular mechanisms underlying the role of 20-HETE in the development of obesity-related hypertension remain unclear, necessitating this study. METHODS Cytochrome P450 4F2 (CYP4F2) transgenic mice fed high-fat diet (HFD) were used as research animal models. The expression of renal ion transport molecules targeted by 20-HETE was evaluated by real-time PCR and Western blot (WB). The regulatory effect of 20-HETE and HFD on renal Na+-K+-2Cl- cotransporter, isoform 2 (NKCC2) was explored by immunoprecipitation, WB, and luciferase assay. RESULTS A 2-week HFD feeding dramatically decreased protein abundance but increased renal NKCC2 mRNA expression in CYP4F2 transgenic mice. The decrease in NKCC2 protein was demonstrated to be due to ubiquitination induced by the synergy between 20-HETE and HFD. The increased PPAR-γ protein in CYP4F2 transgenic mice fed HFD and the activation of rosiglitazone on the luciferase reporter construct of the NKCC2 promoter demonstrated that the increase in NKCC2 mRNA in CYP4F2 transgenic mice fed HFD was a consequence of elevated PPAR-γ protein induced by the synergy between 20-HETE and HFD. CONCLUSIONS Our data demonstrated that the synergy between 20-HETE and HFD could decrease NKCC2 protein via posttranslational ubiquitination, which was thought to be the main mechanism underlying the short-term effect in response to HFD and might be responsible for the adaptive modulation of renal NKCC2 to resist sodium retention. Moreover, the increased NKCC2 mRNA expression via PPAR-γ-induced transcriptional regulation was thought to be the main mechanism underlying the long-term effect in response to HFD and plays a pivotal role in the development of obesity-related hypertension.
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Affiliation(s)
- Jingjing Wu
- Department of Medical Genetics, School of Life Sciences, China Medical University, Shenyang, China,
| | - Guangrui Lai
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Fangjie Chen
- Department of Medical Genetics, School of Life Sciences, China Medical University, Shenyang, China
| | - Bijun Zhang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yanyan Zhao
- Department of Medical Genetics, School of Life Sciences, China Medical University, Shenyang, China
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Fang S, Livergood MC, Nakagawa P, Wu J, Sigmund CD. Role of the Peroxisome Proliferator Activated Receptors in Hypertension. Circ Res 2021; 128:1021-1039. [PMID: 33793338 DOI: 10.1161/circresaha.120.318062] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nuclear receptors represent a large family of ligand-activated transcription factors which sense the physiological environment and make long-term adaptations by mediating changes in gene expression. In this review, we will first discuss the fundamental mechanisms by which nuclear receptors mediate their transcriptional responses. We will focus on the PPAR (peroxisome proliferator-activated receptor) family of adopted orphan receptors paying special attention to PPARγ, the isoform with the most compelling evidence as an important regulator of arterial blood pressure. We will review genetic data showing that rare mutations in PPARγ cause severe hypertension and clinical trial data which show that PPARγ activators have beneficial effects on blood pressure. We will detail the tissue- and cell-specific molecular mechanisms by which PPARs in the brain, kidney, vasculature, and immune system modulate blood pressure and related phenotypes, such as endothelial function. Finally, we will discuss the role of placental PPARs in preeclampsia, a life threatening form of hypertension during pregnancy. We will close with a viewpoint on future research directions and implications for developing novel therapies.
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Affiliation(s)
- Shi Fang
- Department of Physiology, Cardiovascular Center (S.F., P.N., J.W., C.D.S.), Medical College of Wisconsin, Milwaukee.,Department of Neuroscience and Pharmacology, University of Iowa (S.F.)
| | - M Christine Livergood
- Department of Obstetrics and Gynecology (M.C.L.), Medical College of Wisconsin, Milwaukee
| | - Pablo Nakagawa
- Department of Physiology, Cardiovascular Center (S.F., P.N., J.W., C.D.S.), Medical College of Wisconsin, Milwaukee
| | - Jing Wu
- Department of Physiology, Cardiovascular Center (S.F., P.N., J.W., C.D.S.), Medical College of Wisconsin, Milwaukee
| | - Curt D Sigmund
- Department of Physiology, Cardiovascular Center (S.F., P.N., J.W., C.D.S.), Medical College of Wisconsin, Milwaukee
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Mao Z, Valluru MK, Ong ACM. Drug repurposing in autosomal dominant polycystic kidney disease: back to the future with pioglitazone. Clin Kidney J 2021; 14:1715-1718. [PMID: 34221378 PMCID: PMC8243263 DOI: 10.1093/ckj/sfab062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Indexed: 11/16/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited cause of end-stage kidney failure. At present, only one drug, tolvaptan, has been approved for use to slow disease progression, but its use is limited by reduced tolerability and idiosyncratic liver toxicity. Thiazolidinediones were first developed as insulin-sensitizers but also regulate gene transcription in multiple tissues, leading to systemic effects on metabolism, inflammation and vascular reactivity. In this issue, Blazer-Yost et al. report the results of a single-centre Phase 1b double-blind placebo-controlled crossover study of the peroxisome proliferator-activated receptor γ (PPAR-γ) agonist pioglitazone in 18 ADPKD patients. Encouragingly, there were no major safety signals, although evidence of efficacy could not be demonstrated due to the small sample size. We review the preclinical evidence for the use of PPAR-γ agonists in ADPKD and speculate on the likely beneficial and adverse clinical effects of this interesting class of compounds in a future trial.
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Affiliation(s)
- Zhiguo Mao
- Division of Nephrology, Changzheng Hospital, Second Military Medical University, Shanghai, People's Republic of China
| | - Manoj K Valluru
- Department of Infection, Immunity and Cardiovascular Disease, Kidney Genetics Group, Academic Nephrology Unit, University of Sheffield Medical School, Sheffield, UK
| | - Albert C M Ong
- Department of Infection, Immunity and Cardiovascular Disease, Kidney Genetics Group, Academic Nephrology Unit, University of Sheffield Medical School, Sheffield, UK
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Sohrabi C, Saberwal B, Lim WY, Tousoulis D, Ahsan S, Papageorgiou N. Heart Failure in Diabetes Mellitus: An Updated Review. Curr Pharm Des 2020; 26:5933-5952. [PMID: 33213313 DOI: 10.2174/1381612826666201118091659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023]
Abstract
Diabetes mellitus (DM) and heart failure (HF) are comorbid conditions associated with significant morbidity and mortality worldwide. Despite the availability of novel and effective therapeutic options and intensive glycaemic control strategies, mortality and hospitalisation rates continue to remain high and the incidence of HF persists. In this review, we described the impact of currently available glucose-lowering therapies in DM with a focus on HF clinical outcomes. Non-conventional modes of management and alternative pathophysiological mechanisms with the potential for therapeutic targeting are also discussed.
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Affiliation(s)
- Catrin Sohrabi
- Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Bunny Saberwal
- Electrophysiology Department, Barts Heart Centre, St. Bartholomew's Hospital, West Smithfield, London, United Kingdom
| | - Wei-Yao Lim
- Electrophysiology Department, Barts Heart Centre, St. Bartholomew's Hospital, West Smithfield, London, United Kingdom
| | - Dimitris Tousoulis
- First Cardiology Department, Hippokration Hospital, Athens University Medical School, Athens, Greece
| | - Syed Ahsan
- Electrophysiology Department, Barts Heart Centre, St. Bartholomew's Hospital, West Smithfield, London, United Kingdom
| | - Nikolaos Papageorgiou
- Electrophysiology Department, Barts Heart Centre, St. Bartholomew's Hospital, West Smithfield, London, United Kingdom
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Abstract
Patients with diabetes mellitus have >2× the risk for developing heart failure (HF; HF with reduced ejection fraction and HF with preserved ejection fraction). Cardiovascular outcomes, hospitalization, and prognosis are worse for patients with diabetes mellitus relative to those without. Beyond the structural and functional changes that characterize diabetic cardiomyopathy, a complex underlying, and interrelated pathophysiology exists. Despite the success of many commonly used antihyperglycemic therapies to lower hyperglycemia in type 2 diabetes mellitus the high prevalence of HF persists. This, therefore, raises the possibility that additional factors beyond glycemia might contribute to the increased HF risk in diabetes mellitus. This review summarizes the state of knowledge about the impact of existing antihyperglycemic therapies on HF and discusses potential mechanisms for beneficial or deleterious effects. Second, we review currently approved pharmacological therapies for HF and review evidence that addresses their efficacy in the context of diabetes mellitus. Dysregulation of many cellular mechanisms in multiple models of diabetic cardiomyopathy and in human hearts have been described. These include oxidative stress, inflammation, endoplasmic reticulum stress, aberrant insulin signaling, accumulation of advanced glycated end-products, altered autophagy, changes in myocardial substrate metabolism and mitochondrial bioenergetics, lipotoxicity, and altered signal transduction such as GRK (g-protein receptor kinase) signaling, renin angiotensin aldosterone signaling and β-2 adrenergic receptor signaling. These pathophysiological pathways might be amenable to pharmacological therapy to reduce the risk of HF in the context of type 2 diabetes mellitus. Successful targeting of these pathways could alter the prognosis and risk of HF beyond what is currently achieved using existing antihyperglycemic and HF therapeutics.
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Affiliation(s)
- Helena C Kenny
- From the Fraternal Order of Eagles Diabetes Research Center, and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City
| | - E Dale Abel
- From the Fraternal Order of Eagles Diabetes Research Center, and Division of Endocrinology and Metabolism, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City
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Vallon V, Unwin R, Inscho EW, Leipziger J, Kishore BK. Extracellular Nucleotides and P2 Receptors in Renal Function. Physiol Rev 2019; 100:211-269. [PMID: 31437091 DOI: 10.1152/physrev.00038.2018] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The understanding of the nucleotide/P2 receptor system in the regulation of renal hemodynamics and transport function has grown exponentially over the last 20 yr. This review attempts to integrate the available data while also identifying areas of missing information. First, the determinants of nucleotide concentrations in the interstitial and tubular fluids of the kidney are described, including mechanisms of cellular release of nucleotides and their extracellular breakdown. Then the renal cell membrane expression of P2X and P2Y receptors is discussed in the context of their effects on renal vascular and tubular functions. Attention is paid to effects on the cortical vasculature and intraglomerular structures, autoregulation of renal blood flow, tubuloglomerular feedback, and the control of medullary blood flow. The role of the nucleotide/P2 receptor system in the autocrine/paracrine regulation of sodium and fluid transport in the tubular and collecting duct system is outlined together with its role in integrative sodium and fluid homeostasis and blood pressure control. The final section summarizes the rapidly growing evidence indicating a prominent role of the extracellular nucleotide/P2 receptor system in the pathophysiology of the kidney and aims to identify potential therapeutic opportunities, including hypertension, lithium-induced nephropathy, polycystic kidney disease, and kidney inflammation. We are only beginning to unravel the distinct physiological and pathophysiological influences of the extracellular nucleotide/P2 receptor system and the associated therapeutic perspectives.
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Affiliation(s)
- Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Robert Unwin
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Edward W Inscho
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Jens Leipziger
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Bellamkonda K Kishore
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
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Akiyama TE, Skelhorne-Gross GE, Lightbody ED, Rubino RE, Shi JY, McNamara LA, Sharma N, Zycband EI, Gonzalez FJ, Liu H, Woods JW, Chang CH, Berger JP, Nicol CJB. Endothelial Cell-Targeted Deletion of PPAR γ Blocks Rosiglitazone-Induced Plasma Volume Expansion and Vascular Remodeling in Adipose Tissue. J Pharmacol Exp Ther 2019; 368:514-523. [PMID: 30606762 PMCID: PMC11047031 DOI: 10.1124/jpet.118.250985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 12/06/2018] [Indexed: 12/13/2022] Open
Abstract
Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor γ (PPARγ) agonists that represent an effective class of insulin-sensitizing agents; however, clinical use is associated with weight gain and peripheral edema. To elucidate the role of PPARγ expression in endothelial cells (ECs) in these side effects, EC-targeted PPARγ knockout (Pparg ΔEC) mice were placed on a high-fat diet to promote PPARγ agonist-induced plasma volume expansion, and then treated with the TZD rosiglitazone. Compared with Pparg-floxed wild-type control (Pparg f/f) mice, Pparg ΔEC treated with rosiglitazone are resistant to an increase in extracellular fluid, water content in epididymal and inguinal white adipose tissue, and plasma volume expansion. Interestingly, histologic assessment confirmed significant rosiglitazone-mediated capillary dilation within white adipose tissue of Pparg f/f mice, but not Pparg ΔEC mice. Analysis of ECs isolated from untreated mice in both strains suggested the involvement of changes in endothelial junction formation. Specifically, compared with cells from Pparg f/f mice, Pparg ΔEC cells had a 15-fold increase in focal adhesion kinase, critically important in EC focal adhesions, and >3-fold significant increase in vascular endothelial cadherin, the main component of focal adhesions. Together, these results indicate that rosiglitazone has direct effects on the endothelium via PPARγ activation and point toward a critical role for PPARγ in ECs during rosiglitazone-mediated plasma volume expansion.
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Affiliation(s)
- Taro E Akiyama
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Graham E Skelhorne-Gross
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Elizabeth D Lightbody
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Rachel E Rubino
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Jia Yue Shi
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Lesley A McNamara
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Neelam Sharma
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Emanuel I Zycband
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Frank J Gonzalez
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Haiying Liu
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - John W Woods
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - C H Chang
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Joel P Berger
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
| | - Christopher J B Nicol
- Cardiometabolic Disorders Department, Merck Research Laboratories, Kenilworth, New Jersey (T.E.A., L.A.M., N.S., E.I.Z., H.L., J.W.W., C.H.C., J.P.B.); Department of Pathology and Molecular Medicine (G.E.S.-G., E.D.L., C.J.B.N.), Cancer Biology and Genetics Division, Cancer Research Institute (R.E.R., C.J.B.N.), and Department of Biomedical and Molecular Sciences (J.Y.S., C.J.B.N.), Queen's University, Kingston, Ontario, Canada; National Cancer Institute, National Institutes of Health, Bethesda, Maryland (F.J.G.); and Takeda Pharmaceuticals International, Inc., Cambridge, Massachusetts (J.P.B.)
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12
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Liu J, Huang Z, Ma W, Peng S, Li Y, Miranda KM, Tian J, Zhang Y. Design and synthesis of rosiglitazone-ferulic acid-nitric oxide donor trihybrids for improving glucose tolerance. Eur J Med Chem 2019; 162:650-665. [PMID: 30481687 DOI: 10.1016/j.ejmech.2018.10.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 09/30/2018] [Accepted: 10/01/2018] [Indexed: 01/11/2023]
Abstract
Glucose intolerance is associated with metabolic syndrome and type 2 diabetes mellitus (T2DM) while some new therapeutic drugs, such as rosiglitazone (Rosi), for T2DM can cause severe cardiovascular side effects. Herein we report the synthesis of Rosi-ferulic acid (FA)-nitric oxide (NO) donor trihybrids to improve glucose tolerance and minimize the side effects. In comparison with Rosi, the most active compound 21 exhibited better effects on improving glucose tolerance, which was associated with its NO production, antioxidant and anti-inflammatory activities. Furthermore, 21 displayed relatively high stability in the simulated gastrointestinal environments and human liver microsomes, and released Rosi in plasma. More importantly, 21, unlike Rosi, had little stimulatory effect on the membrane translocation of aquaporin-2 (AQP2) in kidney collecting duct epithelial cells. These, together with a better safety profile, suggest that the trihybrids, like 21, may be promising candidates for intervention of glucose intolerance-related metabolic syndrome and T2DM.
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Affiliation(s)
- Jingchao Liu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, 210009, China
| | - Zhangjian Huang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, 210009, China
| | - Wenhuan Ma
- State Key Laboratory of Natural Medicines, Department of Physiology, China Pharmaceutical University, Nanjing, 210009, China
| | - Sixun Peng
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, 210009, China
| | - Yunman Li
- State Key Laboratory of Natural Medicines, Department of Physiology, China Pharmaceutical University, Nanjing, 210009, China.
| | - Katrina M Miranda
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, United States.
| | - Jide Tian
- Department of Molecular and Medical Pharmacology, University of California, Los Angeles, CA, 90095, United States
| | - Yihua Zhang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, China Pharmaceutical University, Nanjing, 210009, China.
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13
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Thomas L, Xue J, Dominguez Rieg JA, Rieg T. Contribution of NHE3 and dietary phosphate to lithium pharmacokinetics. Eur J Pharm Sci 2018; 128:1-7. [PMID: 30419292 DOI: 10.1016/j.ejps.2018.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 10/09/2018] [Accepted: 11/08/2018] [Indexed: 01/13/2023]
Abstract
Lithium is one of the mainstays for the treatment of bipolar disorder despite its side effects on the endocrine, neurological, and renal systems. Experimentally, lithium has been used as a measure to determine proximal tubule reabsorption based on the assumption that lithium and sodium transport go in parallel in the proximal tubule. However, the exact mechanism by which lithium is reabsorbed remains elusive. The majority of proximal tubule sodium reabsorption is directly or indirectly mediated by the sodium-hydrogen exchanger 3 (NHE3). In addition, sodium-phosphate cotransporters have been implicated in renal lithium reabsorption. In order to better understand the role of sodium-phosphate cotransporters involved in lithium (re)absorption, we studied lithium pharmacokinetics in: i) tubule-specific NHE3 knockout mice (NHE3loxloxPax8Cre), and ii) mice challenged with low or high phosphate diets. Intravenous or oral administration of lithium did not result in differences in lithium bioavailability, half-life, maximum plasma concentrations, area under the curve, lithium clearance, or urinary lithium/creatinine ratios between control and NHE3loxloxPax8Cre mice. After one week of dietary phosphate challenges, lithium bioavailability was ~30% lower on low versus high dietary phosphate, possibly the consequence of a smaller area under the curve after oral administration. This was associated with higher apparent lithium clearance after oral administration and lower urinary lithium/creatinine ratios on low versus high dietary phosphate. Collectively, renal NHE3 does not play a role in lithium pharmacokinetics; however, dietary phosphate could have an indirect effect on lithium bioavailability and lithium disposition.
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Affiliation(s)
- Linto Thomas
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33612, USA
| | - Jianxiang Xue
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33612, USA
| | - Jessica A Dominguez Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33612, USA
| | - Timo Rieg
- Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL 33612, USA.
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14
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Milano S, Carmosino M, Gerbino A, Svelto M, Procino G. Hereditary Nephrogenic Diabetes Insipidus: Pathophysiology and Possible Treatment. An Update. Int J Mol Sci 2017; 18:ijms18112385. [PMID: 29125546 PMCID: PMC5713354 DOI: 10.3390/ijms18112385] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 11/03/2017] [Accepted: 11/07/2017] [Indexed: 12/17/2022] Open
Abstract
Under physiological conditions, excessive loss of water through the urine is prevented by the release of the antidiuretic hormone arginine-vasopressin (AVP) from the posterior pituitary. In the kidney, AVP elicits a number of cellular responses, which converge on increasing the osmotic reabsorption of water in the collecting duct. One of the key events triggered by the binding of AVP to its type-2 receptor (AVPR2) is the exocytosis of the water channel aquaporin 2 (AQP2) at the apical membrane the principal cells of the collecting duct. Mutations of either AVPR2 or AQP2 result in a genetic disease known as nephrogenic diabetes insipidus, which is characterized by the lack of responsiveness of the collecting duct to the antidiuretic action of AVP. The affected subject, being incapable of concentrating the urine, presents marked polyuria and compensatory polydipsia and is constantly at risk of severe dehydration. The molecular bases of the disease are fully uncovered, as well as the genetic or clinical tests for a prompt diagnosis of the disease in newborns. A real cure for nephrogenic diabetes insipidus (NDI) is still missing, and the main symptoms of the disease are handled with s continuous supply of water, a restrictive diet, and nonspecific drugs. Unfortunately, the current therapeutic options are limited and only partially beneficial. Further investigation in vitro or using the available animal models of the disease, combined with clinical trials, will eventually lead to the identification of one or more targeted strategies that will improve or replace the current conventional therapy and grant NDI patients a better quality of life. Here we provide an updated overview of the genetic defects causing NDI, the most recent strategies under investigation for rescuing the activity of mutated AVPR2 or AQP2, or for bypassing defective AVPR2 signaling and restoring AQP2 plasma membrane expression.
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Affiliation(s)
- Serena Milano
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Monica Carmosino
- Department of Sciences, University of Basilicata, 85100 Potenza, Italy.
| | - Andrea Gerbino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Maria Svelto
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
| | - Giuseppe Procino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70126 Bari, Italy.
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15
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Davidson MA, Mattison DR, Azoulay L, Krewski D. Thiazolidinedione drugs in the treatment of type 2 diabetes mellitus: past, present and future. Crit Rev Toxicol 2017; 48:52-108. [PMID: 28816105 DOI: 10.1080/10408444.2017.1351420] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Thiazolidinedione (TZD) drugs used in the treatment of type 2 diabetes mellitus (T2DM) have proven effective in improving insulin sensitivity, hyperglycemia, and lipid metabolism. Though well tolerated by some patients, their mechanism of action as ligands of peroxisome proliferator-activated receptors (PPARs) results in the activation of several pathways in addition to those responsible for glycemic control and lipid homeostasis. These pathways, which include those related to inflammation, bone formation, and cell proliferation, may lead to adverse health outcomes. As treatment with TZDs has been associated with adverse hepatic, cardiovascular, osteological, and carcinogenic events in some studies, the role of TZDs in the treatment of T2DM continues to be debated. At the same time, new therapeutic roles for TZDs are being investigated, with new forms and isoforms currently in the pre-clinical phase for use in the prevention and treatment of some cancers, inflammatory diseases, and other conditions. The aims of this review are to provide an overview of the mechanism(s) of action of TZDs, a review of their safety for use in the treatment of T2DM, and a perspective on their current and future therapeutic roles.
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Affiliation(s)
- Melissa A Davidson
- a Faculty of Health Sciences , University of Ottawa , Ottawa , Canada.,b McLaughlin Centre for Population Health Risk Assessment , Ottawa , Canada
| | - Donald R Mattison
- b McLaughlin Centre for Population Health Risk Assessment , Ottawa , Canada.,c Risk Sciences International , Ottawa , Canada
| | - Laurent Azoulay
- d Center for Clinical Epidemiology , Lady Davis Research Institute, Jewish General Hospital , Montreal , Canada.,e Department of Oncology , McGill University , Montreal , Canada
| | - Daniel Krewski
- a Faculty of Health Sciences , University of Ottawa , Ottawa , Canada.,b McLaughlin Centre for Population Health Risk Assessment , Ottawa , Canada.,c Risk Sciences International , Ottawa , Canada.,f Faculty of Medicine , University of Ottawa , Ottawa , Canada
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16
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Goltsman I, Khoury EE, Winaver J, Abassi Z. Does Thiazolidinedione therapy exacerbate fluid retention in congestive heart failure? Pharmacol Ther 2016; 168:75-97. [PMID: 27598860 DOI: 10.1016/j.pharmthera.2016.09.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ever-growing global burden of congestive heart failure (CHF) and type 2 diabetes mellitus (T2DM) as well as their co-existence necessitate that anti-diabetic pharmacotherapy will modulate the cardiovascular risk inherent to T2DM while complying with the accompanying restrictions imposed by CHF. The thiazolidinedione (TZD) family of peroxisome proliferator-activated receptor γ (PPARγ) agonists initially provided a promising therapeutic option in T2DM owing to anti-diabetic efficacy combined with pleiotropic beneficial cardiovascular effects. However, the utility of TZDs in T2DM has declined in the past decade, largely due to concomitant adverse effects of fluid retention and edema formation attributed to salt-retaining effects of PPARγ activation on the nephron. Presumably, the latter effects are potentially deleterious in the context of pre-existing fluid retention in CHF. However, despite a considerable body of evidence on mechanisms responsible for TZD-induced fluid retention suggesting that this class of drugs is rightfully prohibited from use in CHF patients, there is a paucity of experimental and clinical studies that investigate the effects of TZDs on salt and water homeostasis in the CHF setting. In an attempt to elucidate whether TZDs actually exacerbate the pre-existing fluid retention in CHF, our review summarizes the pathophysiology of fluid retention in CHF. Moreover, we thoroughly review the available data on TZD-induced fluid retention and proposed mechanisms in animals and patients. Finally, we will present recent studies challenging the common notion that TZDs worsen renal salt and water retention in CHF.
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Affiliation(s)
- Ilia Goltsman
- Department of Physiology, Biophysics and Systems Biology, The Bruce Rappaport, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Emad E Khoury
- Department of Physiology, Biophysics and Systems Biology, The Bruce Rappaport, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Joseph Winaver
- Department of Physiology, Biophysics and Systems Biology, The Bruce Rappaport, Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Zaid Abassi
- Department of Physiology, Biophysics and Systems Biology, The Bruce Rappaport, Rappaport Faculty of Medicine, Technion, Haifa, Israel; Department of Laboratory Medicine, Rambam Human Health Care Campus, Haifa, Israel.
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17
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Giri SR, Bhoi B, Jain MR, Gatne MM. Cardioprotective role of peroxisome proliferator-activated receptor-γ agonist, rosiglitazone in a unique murine model of diabetic cardiopathy. Life Sci 2016; 162:1-13. [PMID: 27530514 DOI: 10.1016/j.lfs.2016.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 08/09/2016] [Accepted: 08/12/2016] [Indexed: 10/21/2022]
Abstract
AIMS Rosiglitazone (RSZ), a PPARγ agonist was potent efficacious insulin sensitizing blockbuster drug for treatment of Type 2 diabetes mellitus (T2DM) but the benefit of PPARγ activation in congestive heart failure (CHF) was controversial. The present work was planned to study the role of RSZ in diabetic cardiopathy. MAIN METHODS Zucker fa/fa rats, the genetic model of T2DM were subjected to constriction of suprarenal abdominal aorta so that they represent a combined model of diabetes and cardiopathy. The development cardiopathy was assessed biochemically (plasma BNP and aldosterone levels), using echocardiography and expression angiotensin II receptor type 1a gene in heart and Endothelin-1 gene in aorta. Rats were treated with RSZ and in combination with amiloride for four weeks and were assessed to evaluate the effect of RSZ or amiloride or its combination on antidiabetic activity, adverse or toxic effects and congestive heart failure status. KEY FINDINGS RSZ shows its anti-diabetic effect from 0.3mg/kg dose onwards and at 3mg/kg dose levels it caused beneficial effects (reduction of blood pressure) on cardiovascular system and at highest (30mg/kg) dose it starts showing adverse effects like body weight gain, edema, left ventricular hypertrophy. However, when highest dose of RSZ animals were treated with amiloride (ENaC inhibitor) at 2mg/kg the reversal of the adverse effects was evident, indicating the combination of RSZ and amiloride is beneficial in diabetic cardiopathy model. SIGNIFICANCE RSZ and amiloride combination appeared promising treatment in diabetic patients with cardiopathy without any side effect.
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Affiliation(s)
- Suresh R Giri
- Department of Pharmacology & Toxicology, Zydus Research Centre, Cadila Healthcare Limited, Sarkhej-Bavla N.H. No. 8A, Moraiya, Ahmedabad 382 213, Gujarat, India; Department of Pharmacology & Toxicology, Bombay Veterinary College, Parel, Mumbai 400012, India.
| | - Bibhuti Bhoi
- Department of Pharmacology & Toxicology, Zydus Research Centre, Cadila Healthcare Limited, Sarkhej-Bavla N.H. No. 8A, Moraiya, Ahmedabad 382 213, Gujarat, India
| | - Mukul R Jain
- Department of Pharmacology & Toxicology, Zydus Research Centre, Cadila Healthcare Limited, Sarkhej-Bavla N.H. No. 8A, Moraiya, Ahmedabad 382 213, Gujarat, India
| | - Madhumanjiri M Gatne
- Department of Pharmacology & Toxicology, Bombay Veterinary College, Parel, Mumbai 400012, India
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18
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Boscardin E, Alijevic O, Hummler E, Frateschi S, Kellenberger S. The function and regulation of acid-sensing ion channels (ASICs) and the epithelial Na(+) channel (ENaC): IUPHAR Review 19. Br J Pharmacol 2016; 173:2671-701. [PMID: 27278329 DOI: 10.1111/bph.13533] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/19/2016] [Accepted: 06/02/2016] [Indexed: 12/30/2022] Open
Abstract
Acid-sensing ion channels (ASICs) and the epithelial Na(+) channel (ENaC) are both members of the ENaC/degenerin family of amiloride-sensitive Na(+) channels. ASICs act as proton sensors in the nervous system where they contribute, besides other roles, to fear behaviour, learning and pain sensation. ENaC mediates Na(+) reabsorption across epithelia of the distal kidney and colon and of the airways. ENaC is a clinically used drug target in the context of hypertension and cystic fibrosis, while ASIC is an interesting potential target. Following a brief introduction, here we will review selected aspects of ASIC and ENaC function. We discuss the origin and nature of pH changes in the brain and the involvement of ASICs in synaptic signalling. We expose how in the peripheral nervous system, ASICs cover together with other ion channels a wide pH range as proton sensors. We introduce the mechanisms of aldosterone-dependent ENaC regulation and the evidence for an aldosterone-independent control of ENaC activity, such as regulation by dietary K(+) . We then provide an overview of the regulation of ENaC by proteases, a topic of increasing interest over the past few years. In spite of the profound differences in the physiological and pathological roles of ASICs and ENaC, these channels share many basic functional and structural properties. It is likely that further research will identify physiological contexts in which ASICs and ENaC have similar or overlapping roles.
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Affiliation(s)
- Emilie Boscardin
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Omar Alijevic
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
| | - Edith Hummler
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland
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19
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Thiazolidinediones and Edema: Recent Advances in the Pathogenesis of Thiazolidinediones-Induced Renal Sodium Retention. PPAR Res 2015; 2015:646423. [PMID: 26074951 PMCID: PMC4446477 DOI: 10.1155/2015/646423] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/03/2015] [Indexed: 02/07/2023] Open
Abstract
Thiazolidinediones (TZDs) are one of the major classes of antidiabetic drugs that are used widely. TZDs improve insulin resistance by activating peroxisome proliferator-activated receptor gamma (PPARγ) and ameliorate diabetic and other nephropathies, at least, in experimental animals. However, TZDs have side effects, such as edema, congestive heart failure, and bone fracture, and may increase bladder cancer risk. Edema and heart failure, which both probably originate from renal sodium retention, are of great importance because these side effects make it difficult to continue the use of TZDs. However, the pathogenesis of edema remains a matter of controversy. Initially, upregulation of the epithelial sodium channel (ENaC) in the collecting ducts by TZDs was thought to be the primary cause of edema. However, the results of other studies do not support this view. Recent data suggest the involvement of transporters in the proximal tubule, such as sodium-bicarbonate cotransporter and sodium-proton exchanger. Other studies have suggested that sodium-potassium-chloride cotransporter 2 in the thick ascending limb of Henle and aquaporins are also possible targets for TZDs. This paper will discuss the recent advances in the pathogenesis of TZD-induced sodium reabsorption in the renal tubules and edema.
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20
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Seki G, Nakamura M, Suzuki M, Satoh N, Horita S. Species differences in regulation of renal proximal tubule transport by certain molecules. World J Nephrol 2015; 4:307-312. [PMID: 25949945 PMCID: PMC4419141 DOI: 10.5527/wjn.v4.i2.307] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 12/24/2014] [Accepted: 01/20/2015] [Indexed: 02/06/2023] Open
Abstract
Renal proximal tubules (PTs) play important roles in the regulation of acid/base, plasma volume and blood pressure. Recent studies suggest that there are substantial species differences in the regulation of PT transport. For example, thiazolidinediones (TZDs) are widely used for the treatment of type 2 diabetes mellitus, but the use of TZDs is associated with fluid overload. In addition to the transcriptional enhancement of sodium transport in distal nephrons, TZDs rapidly stimulate PT sodium transport via a non-genomic mechanism depending on peroxisome proliferator activated receptor γ/Src/epidermal growth factor receptor (EGFR)/MEK/ERK. In mouse PTs, however, TZDs fail to stimulate PT transport probably due to constitutive activation of Src/EGFR/ERK pathway. This unique activation of Src/ERK may also affect the effect of high concentrations of insulin on mouse PT transport. On the other hand, the effect of angiotensin II (Ang II) on PT transport is known to be biphasic in rabbits, rats, and mice. However, Ang II induces a concentration-dependent, monophasic transport stimulation in human PTs. The contrasting responses to nitric oxide/guanosine 3’,5’-cyclic monophosphate pathway may largely explain these different effects of Ang II on PT transport. In this review, we focus on the recent findings on the species differences in the regulation of PT transport, which may help understand the species-specific mechanisms underlying edema formation and/or hypertension occurrence.
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Mironova E, Chen Y, Pao AC, Roos KP, Kohan DE, Bugaj V, Stockand JD. Activation of ENaC by AVP contributes to the urinary concentrating mechanism and dilution of plasma. Am J Physiol Renal Physiol 2015; 308:F237-43. [PMID: 25391898 PMCID: PMC4596725 DOI: 10.1152/ajprenal.00246.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 11/06/2014] [Indexed: 12/11/2022] Open
Abstract
Arginine vasopressin (AVP) activates the epithelial Na(+) channel (ENaC). The physiological significance of this activation is unknown. The present study tested if activation of ENaC contributes to AVP-sensitive urinary concentration. Consumption of a 3% NaCl solution induced hypernatremia and plasma hypertonicity in mice. Plasma AVP concentration and urine osmolality increased in hypernatremic mice in an attempt to compensate for increases in plasma tonicity. ENaC activity was elevated in mice that consumed 3% NaCl solution compared with mice that consumed a diet enriched in Na(+) with ad libitum tap water; the latter diet does not cause hypernatremia. To determine whether the increase in ENaC activity in mice that consumed 3% NaCl solution served to compensate for hypernatremia, mice were treated with the ENaC inhibitor benzamil. Coadministration of benzamil with 3% NaCl solution decreased urinary osmolality and increased urine flow so that urinary Na(+) excretion increased with no effect on urinary Na(+) concentration. This decrease in urinary concentration further increased plasma Na(+) concentration, osmolality, and AVP concentration in these already hypernatremic mice. Benzamil similarly compromised urinary concentration in water-deprived mice and in mice treated with desmopressin. These results demonstrate that stimulation of ENaC by AVP plays a critical role in water homeostasis by facilitating urinary concentration, which can compensate for hypernatremia or exacerbate hyponatremia. The present findings are consistent with ENaC in addition to serving as a final effector of the renin-angiotensin-aldosterone system and blood pressure homeostasis, also playing a key role in water homeostasis by regulating urine concentration and dilution of plasma.
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Affiliation(s)
- Elena Mironova
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas
| | - Yu Chen
- Department of Medicine, Stanford University School of Medicine, and Veterans Affairs Palo Alto Health Care System, Palo Alto, California; and
| | - Alan C Pao
- Department of Medicine, Stanford University School of Medicine, and Veterans Affairs Palo Alto Health Care System, Palo Alto, California; and
| | - Karl P Roos
- Division of Nephrology, University of Utah Health Science Center, Salt Lake City, Utah
| | - Donald E Kohan
- Division of Nephrology, University of Utah Health Science Center, Salt Lake City, Utah
| | - Vladislav Bugaj
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas
| | - James D Stockand
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas;
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Fu Y, Gerasimova M, Batz F, Kuczkowski A, Alam Y, Sanders PW, Ronzaud C, Hummler E, Vallon V. PPARγ agonist-induced fluid retention depends on αENaC expression in connecting tubules. Nephron Clin Pract 2014; 129:68-74. [PMID: 25531136 DOI: 10.1159/000370254] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 11/27/2014] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND/AIMS Thiazolidinediones (TZDs, like rosiglitazone (RGZ)) are peroxisome proliferator-activated receptor γ (PPARγ) agonists used to treat type 2 diabetes. Clinical limitations include TZD-induced fluid retention and body weight (BW) increase, which are inhibited by amiloride, an epithelial-sodium channel (ENaC) blocker. RGZ-induced fluid retention is maintained in mice with αENaC knockdown in the collecting duct (CD). Since ENaC in the connecting tubule (CNT) rather than in CD appears to be critical for normal NaCl retention, we aimed to further explore the role of ENaC in CNT in RGZ-induced fluid retention. METHODS Mice with conditional inactivation of αENaC in both CNT and CD were used (αENaC lox/lox AQP2-Cre; 'αENaC-CNT/CD-KO') and compared with littermate controls (αENaC lox/lox mice; 'WT'). BW was monitored and total body water (TBW) and extracellular fluid volume (ECF) were determined by bioelectrical impedance spectroscopy (BIS) before and after RGZ (320 mg/kg diet for 10 days). RESULTS On regular NaCl diet, αENaC-CNT/CD-KO had normal BW, TBW, ECF, hematocrit, and plasma Na(+), K(+), and creatinine, associated with an increase in plasma aldosterone compared with WT. Challenging αENaC-CNT/CD-KO with a low NaCl diet unmasked impaired NaCl and K homeostasis, consistent with effective knockdown of αENaC. In WT, RGZ increased BW (+6.1%), TBW (+8.4%) and ECF (+10%), consistent with fluid retention. These changes were significantly attenuated in αENaC-CNT/CD-KO (+3.4, 1.3, and 4.3%). CONCLUSION Together with the previous studies, the current results are consistent with a role of αENaC in CNT in RGZ-induced fluid retention, which dovetails with the physiological relevance of ENaC in this segment.
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Preserved Na/HCO3 cotransporter sensitivity to insulin may promote hypertension in metabolic syndrome. Kidney Int 2014; 87:535-42. [PMID: 25354240 DOI: 10.1038/ki.2014.351] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 08/29/2014] [Accepted: 09/04/2014] [Indexed: 01/01/2023]
Abstract
Hyperinsulinemia can contribute to hypertension through effects on sodium transport. To test whether the stimulatory effect of insulin on renal proximal tubule sodium transport is preserved in insulin resistance, we compared the effects of insulin on abdominal adipocytes and proximal tubules in rats and humans. Insulin markedly stimulated the sodium-bicarbonate cotransporter (NBCe1) activity in isolated proximal tubules through the phosphoinositide 3-kinase (PI3-K) pathway. Gene silencing in rats showed that while insulin receptor substrate (IRS)1 mediates the insulin effect on glucose uptake into adipocytes, IRS2 mediates the insulin effect on proximal tubule transport. The stimulatory effect of insulin on glucose uptake into adipocytes was severely reduced, but its stimulatory effect on NBCe1 activity was completely preserved in insulin-resistant Otsuka Long-Evans Tokushima Fatty (OLETF) rats and patients with insulin resistance. Despite widespread reduction of IRS1 and IRS2 expression in insulin-sensitive tissues, IRS2 expression in the kidney cortex was exceptionally preserved in both OLETF rats and patients with insulin resistance. Unlike liver, acute insulin injection failed to change the expression levels of IRS2 and sterol regulatory element-binding protein 1 in rat kidney cortex, indicating that regulatory mechanisms of IRS2 expression are distinct in liver and kidney. Thus, preserved stimulation of proximal tubule transport through the insulin/IRS2/PI3-K pathway may play an important role in the pathogenesis of hypertension associated with metabolic syndrome.
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Lefterova MI, Haakonsson AK, Lazar MA, Mandrup S. PPARγ and the global map of adipogenesis and beyond. Trends Endocrinol Metab 2014; 25:293-302. [PMID: 24793638 PMCID: PMC4104504 DOI: 10.1016/j.tem.2014.04.001] [Citation(s) in RCA: 428] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 04/08/2014] [Accepted: 04/09/2014] [Indexed: 10/25/2022]
Abstract
Peroxisome proliferator-activated receptor γ (PPARγ) is a member of the nuclear receptor (NR) superfamily of ligand-dependent transcription factors (TFs) and function as a master regulator of adipocyte differentiation and metabolism. We review recent breakthroughs in the understanding of PPARγ gene regulation and function in the chromatin context. It is now clear that multiple TFs team up to induce PPARγ during adipogenesis, and that other TFs cooperate with PPARγ to ensure adipocyte-specific genomic binding and function. We discuss how this differs in other PPARγ-expressing cells such as macrophages and how these genome-wide mechanisms are preserved across species despite modest conservation of specific binding sites. These emerging considerations inform our understanding of PPARγ function as well as of adipocyte development and physiology.
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Affiliation(s)
- Martina I Lefterova
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA; Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Anders K Haakonsson
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark
| | - Mitchell A Lazar
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, and Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Susanne Mandrup
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense, Denmark.
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Roles of renal proximal tubule transport in acid/base balance and blood pressure regulation. BIOMED RESEARCH INTERNATIONAL 2014; 2014:504808. [PMID: 24982885 PMCID: PMC4058521 DOI: 10.1155/2014/504808] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 05/16/2014] [Indexed: 02/06/2023]
Abstract
Sodium-coupled bicarbonate absorption from renal proximal tubules (PTs) plays a pivotal role in the maintenance of systemic acid/base balance. Indeed, mutations in the Na+-HCO3− cotransporter NBCe1, which mediates a majority of bicarbonate exit from PTs, cause severe proximal renal tubular acidosis associated with ocular and other extrarenal abnormalities. Sodium transport in PTs also plays an important role in the regulation of blood pressure. For example, PT transport stimulation by insulin may be involved in the pathogenesis of hypertension associated with insulin resistance. Type 1 angiotensin (Ang) II receptors in PT are critical for blood pressure homeostasis. Paradoxically, the effects of Ang II on PT transport are known to be biphasic. Unlike in other species, however, Ang II is recently shown to dose-dependently stimulate human PT transport via nitric oxide/cGMP/ERK pathway, which may represent a novel therapeutic target in human hypertension. In this paper, we will review the physiological and pathophysiological roles of PT transport.
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Masuda T, Fu Y, Eguchi A, Czogalla J, Rose MA, Kuczkowski A, Gerasimova M, Feldstein AE, Scadeng M, Vallon V. Dipeptidyl peptidase IV inhibitor lowers PPARγ agonist-induced body weight gain by affecting food intake, fat mass, and beige/brown fat but not fluid retention. Am J Physiol Endocrinol Metab 2014; 306:E388-98. [PMID: 24347054 PMCID: PMC3923087 DOI: 10.1152/ajpendo.00124.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Peroxisome proliferator-activated receptor-γ (PPARγ) agonists like pioglitazone (PGZ) are effective antidiabetic drugs, but they induce fluid retention and body weight (BW) gain. Dipeptidyl peptidase IV (DPP IV) inhibitors are antidiabetic drugs that enhance renal Na(+) and fluid excretion. Therefore, we examined whether the DPP IV inhibitor alogliptin (ALG) ameliorates PGZ-induced BW gain. Male Sv129 mice were treated with vehicle (repelleted diet), PGZ (220 mg/kg diet), ALG (300 mg/kg diet), or a combination of PGZ and ALG (PGZ + ALG) for 14 days. PGZ + ALG prevented the increase in BW observed with PGZ but did not attenuate the increase in body fluid content determined by bioimpedance spectroscopy (BIS). BIS revealed that ALG alone had no effect on fat mass (FM) but enhanced the FM-lowering effect of PGZ; MRI analysis confirmed the latter and showed reductions in visceral and inguinal subcutaneous (sc) white adipose tissue (WAT). ALG but not PGZ decreased food intake and plasma free fatty acid concentrations. Conversely, PGZ but not ALG increased mRNA expression of thermogenesis mediator uncoupling protein 1 in epididymal WAT. Adding ALG to PGZ treatment increased the abundance of multilocular cell islets in sc WAT, and PGZ + ALG increased the expression of brown-fat-like "beige" cell marker TMEM26 in sc WAT and interscapular brown adipose tissue and increased rectal temperature vs. vehicle. In summary, DPP IV inhibition did not attenuate PPARγ agonist-induced fluid retention but prevented BW gain by reducing FM. This involved ALG inhibition of food intake and was associated with food intake-independent synergistic effects of PPARγ agonism and DPP-IV inhibition on beige/brown fat cells and thermogenesis.
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Gilardi F, Giudici M, Mitro N, Maschi O, Guerrini U, Rando G, Maggi A, Cermenati G, Laghezza A, Loiodice F, Pochetti G, Lavecchia A, Caruso D, De Fabiani E, Bamberg K, Crestani M. LT175 is a novel PPARα/γ ligand with potent insulin-sensitizing effects and reduced adipogenic properties. J Biol Chem 2014; 289:6908-6920. [PMID: 24451380 DOI: 10.1074/jbc.m113.506394] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-dependent transcription factors regulating lipid and glucose metabolism. Ongoing drug discovery programs aim to develop dual PPARα/γ agonists devoid of the side effects of the marketed antidiabetic agents thiazolidinediones and the dual agonists glitazars. Recently, we described a new dual PPARα/γ ligand, LT175, with a partial agonist profile against PPARγ and interacting with a newly identified region of the PPARγ-ligand binding domain (1). Here we show that LT175 differentially activated PPARγ target genes involved in fatty acid esterification and storage in 3T3-L1-derived adipocytes. This resulted in a less severe lipid accumulation compared with that triggered by rosiglitazone, suggesting that LT175 may have a lower adipogenic activity. Consistent with this hypothesis, in vivo administration of LT175 to mice fed a high-fat diet decreased body weight, adipocyte size, and white adipose tissue mass, as assessed by magnetic resonance imaging. Furthermore, LT175 significantly reduced plasma glucose, insulin, non-esterified fatty acids, triglycerides, and cholesterol and increased circulating adiponectin and fibroblast growth factor 21 levels. Oral glucose and insulin tolerance tests showed that the compound improves glucose homeostasis and insulin sensitivity. Moreover, we demonstrate that the peculiar interaction of LT175 with PPARγ affected the recruitment of the coregulators cyclic-AMP response element-binding protein-binding protein and nuclear corepressor 1 (NCoR1), fundamentals for the PPARγ-mediated adipogenic program. In conclusion, our results describe a new PPAR ligand, modulating lipid and glucose metabolism with reduced adipogenic activity, that may be used as a model for a series of novel molecules with an improved pharmacological profile for the treatment of dyslipidemia and type 2 diabetes.
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Affiliation(s)
- Federica Gilardi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Marco Giudici
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Nico Mitro
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Omar Maschi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Uliano Guerrini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Gianpaolo Rando
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Adriana Maggi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Gaia Cermenati
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Antonio Laghezza
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", 70125 Bari, Italy
| | - Fulvio Loiodice
- Dipartimento di Farmacia-Scienze del Farmaco, Università degli Studi di Bari "Aldo Moro", 70125 Bari, Italy
| | - Giorgio Pochetti
- Consiglio Nazionale delle Ricerche (CNR), 00016 Montelibretti, Rome, Italy
| | - Antonio Lavecchia
- Dipartimento di Farmacia, "Drug Discovery" Laboratory, Università degli Studi di Napoli "Federico II", 80131 Naples, Italy
| | - Donatella Caruso
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | - Emma De Fabiani
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy
| | | | - Maurizio Crestani
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, 20133 Milan, Italy.
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Diuretics prevent thiazolidinedione-induced cardiac hypertrophy without compromising insulin-sensitizing effects in mice. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 184:442-53. [PMID: 24287404 DOI: 10.1016/j.ajpath.2013.10.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Revised: 10/12/2013] [Accepted: 10/17/2013] [Indexed: 11/20/2022]
Abstract
Much concern has arisen regarding critical adverse effects of thiazolidinediones (TZDs), including rosiglitazone and pioglitazone, on cardiac tissue. Although TZD-induced cardiac hypertrophy (CH) has been attributed to an increase in plasma volume or a change in cardiac nutrient preference, causative roles have not been established. To test the hypothesis that volume expansion directly mediates rosiglitazone-induced CH, mice were fed a high-fat diet with rosiglitazone, and cardiac and metabolic consequences were examined. Rosiglitazone treatment induced volume expansion and CH in wild-type and PPARγ heterozygous knockout (Pparg(+/-)) mice, but not in mice defective for ligand binding (Pparg(P465L/+)). Cotreatment with the diuretic furosemide in wild-type mice attenuated rosiglitazone-induced CH, hypertrophic gene reprogramming, cardiomyocyte apoptosis, hypertrophy-related signal activation, and left ventricular dysfunction. Similar changes were observed in mice treated with pioglitazone. The diuretics spironolactone and trichlormethiazide, but not amiloride, attenuated rosiglitazone effects on volume expansion and CH. Interestingly, expression of glucose and lipid metabolism genes in the heart was altered by rosiglitazone, but these changes were not attenuated by furosemide cotreatment. Importantly, rosiglitazone-mediated whole-body metabolic improvements were not affected by furosemide cotreatment. We conclude that releasing plasma volume reduces adverse effects of TZD-induced volume expansion and cardiac events without compromising TZD actions in metabolic switch in the heart and whole-body insulin sensitivity.
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Stockand JD, Vallon V, Ortiz P. In vivo and ex vivo analysis of tubule function. Compr Physiol 2013; 2:2495-525. [PMID: 23720256 DOI: 10.1002/cphy.c100051] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Analysis of tubule function with in vivo and ex vivo approaches has been instrumental in revealing renal physiology. This work allows assignment of functional significance to known gene products expressed along the nephron, primary of which are proteins involved in electrolyte transport and regulation of these transporters. Not only we have learned much about the key roles played by these transport proteins and their proper regulation in normal physiology but also the combination of contemporary molecular biology and molecular genetics with in vivo and ex vivo analysis opened a new era of discovery informative about the root causes of many renal diseases. The power of in vivo and ex vivo analysis of tubule function is that it preserves the native setting and control of the tubule and proteins within tubule cells enabling them to be investigated in a "real-life" environment with a high degree of precision. In vivo and ex vivo analysis of tubule function continues to provide a powerful experimental outlet for testing, evaluating, and understanding physiology in the context of the novel information provided by sequencing of the human genome and contemporary genetic screening. These tools will continue to be a mainstay in renal laboratories as this discovery process continues and as we continue to identify new gene products functionally compromised in renal disease.
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Affiliation(s)
- James D Stockand
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, USA.
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Asakura J, Hasegawa H, Takayanagi K, Shimazu T, Suge R, Shimizu T, Iwashita T, Tayama Y, Matsuda A, Kanozawa K, Araki N, Mitarai T. Renoprotective effect of pioglitazone by the prevention of glomerular hyperfiltration through the possible restoration of altered macula densa signaling in rats with type 2 diabetic nephropathy. Nephron Clin Pract 2013; 122:83-94. [PMID: 23548923 DOI: 10.1159/000348661] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 02/03/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND/AIMS Pioglitazone (PGZ), one of the thiazolidinediones, has been known to show renoprotective effects. In this study, we focused on the effect of PGZ on glomerular hyperfiltration (GHF), resultant glomerular injury and altered macula densa signaling as a cause of sustained GHF through modified tubuloglomerular feedback in rats with diabetic nephropathy. METHODS Kidneys from 24-week-old male OLETF rats and LET rats, nondiabetic controls, were used for the experiment. PGZ was administered (10 mg/kg/day, p.o.) for 2 weeks from 22 to 24 weeks of age in some of the OLETF rats (OLETF+PGZ). RESULTS Parameters relating GHF, kidney weight, creatinine clearance, urine albumin/creatinine ratio and glomerular surface were all increased in OLETF rats and partially restored in OLETF+PGZ rats. Expressions of desmin and TGF-β were also increased in OLETF rats and restored in OLETF+PGZ rats. The changes in TGF-β expression were confirmed to be independent of podocyte number. Finally, the immunoreactivity of neuronal nitric oxide synthase (nNOS) and cyclooxygenase 2 (COX-2) in the macula densa was assessed for the evaluation of macula densa signaling. Altered intensities of nNOS and COX-2 in OLETF rats were restored in OLETF+PGZ rats, which agreed with the gene expression analysis (nNOS: 100.2 ± 2.9% in LET, 64.2 ± 2.7% in OLETF, 87.4 ± 12.1% in OLETF+PGZ; COX-2: 100.8 ± 7.4% in LET, 249.2 ± 19.4% in OLETF, 179.9 ± 13.5% in OLETF+PGZ; n = 5) and the semiquantitative analysis of nNOS/COX-2-positive cells. CONCLUSION PGZ effectively attenuated the GHF and hyperfiltration-associated glomerular injury in diabetic nephropathy. The restoration of altered macula densa signaling might be involved in the renoprotective effect of PGZ.
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Affiliation(s)
- Juko Asakura
- Department of Nephrology and Hypertension, Saitama Medical Center, Saitama Medical University, Kawagoe, Japan
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Bełtowski J, Rachańczyk J, Włodarczyk M. Thiazolidinedione-induced fluid retention: recent insights into the molecular mechanisms. PPAR Res 2013; 2013:628628. [PMID: 23577024 PMCID: PMC3614122 DOI: 10.1155/2013/628628] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 02/19/2013] [Indexed: 01/11/2023] Open
Abstract
Peroxisome proliferator-activated receptor- γ (PPAR γ ) agonists such as rosiglitazone and pioglitazone are used to improve insulin sensitivity in patients with diabetes mellitus. However, thiazolidinediones induce fluid retention, edema, and sometimes precipitate or exacerbate heart failure in a subset of patients. The mechanism through which thiazolidinediones induce fluid retention is controversial. Most studies suggest that this effect results from the increase in tubular sodium and water reabsorption in the kidney, but the role of specific nephron segments and sodium carriers involved is less clear. Some studies suggested that PPAR γ agonist stimulates Na(+) reabsorption in the collecting duct by activating epithelial Na(+) channel (ENaC), either directly or through serum and glucocorticoid-regulated kinase-1 (SGK-1). However, other studies did not confirm this mechanism and even report the suppression of ENaC. Alternative mechanisms in the collecting duct include stimulation of non-ENaC sodium channel or inhibition of chloride secretion to the tubular lumen. In addition, thiazolidinediones may augment sodium reabsorption in the proximal tubule by stimulating the expression and activity of apical Na(+)/H(+) exchanger-3 and basolateral Na(+)-HCO3 (-) cotransporter as well as of Na(+),K(+)-ATPase. These effects are mediated by PPAR γ -induced nongenomic transactivation of the epidermal growth factor receptor and downstream extracellular signal-regulated kinases (ERK).
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Affiliation(s)
- Jerzy Bełtowski
- Department of Pathophysiology, Medical University of Lublin, 8 Jaczewskiego, 20090 Lublin, Poland
| | - Jolanta Rachańczyk
- Department of Pathophysiology, Medical University of Lublin, 8 Jaczewskiego, 20090 Lublin, Poland
| | - Mirosław Włodarczyk
- Department of Pathophysiology, Medical University of Lublin, 8 Jaczewskiego, 20090 Lublin, Poland
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Gathiaka S, Nanayakkara G, Boncher T, Acevedo O, Wyble J, Patel S, Patel A, Shane ME, Bonkowski B, Wieczorek J, Rong Y, Huggins K, Smith F, Amin RH. Design, development and evaluation of novel dual PPARδ/PPARγ agonists. Bioorg Med Chem Lett 2012; 23:873-9. [PMID: 23273519 DOI: 10.1016/j.bmcl.2012.11.060] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 11/07/2012] [Accepted: 11/12/2012] [Indexed: 11/29/2022]
Abstract
Type 2 diabetes is at epidemic proportions and thus development of novel pharmaceutical therapies for improving insulin sensitivity has become of paramount importance. The objectives of the current study were to develop novel dual PPARγ/δ agonists without the deleterious side effects associated with full PPARγ agonists. Docking simulations of 23 novel compounds within the ligand binding domain of PPARγ/δ were performed using AutoDock Vina which consistently reproduced experimental binding poses from known PPAR agonists. Comparisons were made and described with other docking programs AutoDock and Surflex-Dock (from SYBYL-X). Biological evaluation of compounds was accomplished by transcriptional promoter activity assays, quantitative PCR gene analysis for known PPARγ/δ targets as well as in vitro assays for lipid accumulation and mitochondrial biogenesis verses known PPAR agonists. We found one (compound 9) out of the 23 compounds evaluated, to be the most potent and selective dual PPARγ/δ agonist which did not display the deleterious side effects associated with full PPARγ agonists.
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Affiliation(s)
- Symon Gathiaka
- Dept. of Chemistry and Biochemistry, Auburn University, Auburn, AL 36849, USA
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Viswanathan V, Mohan V, Subramani P, Parthasarathy N, Subramaniyam G, Manoharan D, Sundaramoorthy C, Gnudi L, Karalliedde J, Viberti G. Effect of spironolactone and amiloride on thiazolidinedione-induced fluid retention in South Indian patients with type 2 diabetes. Clin J Am Soc Nephrol 2012. [PMID: 23184569 DOI: 10.2215/cjn.06330612] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND AND OBJECTIVES Thiazolidinediones (pioglitazone and rosiglitazone) induce renal epithelial sodium channel (ENaC)-mediated sodium reabsorption, resulting in plasma volume (PV) expansion. Incidence and long-term management of fluid retention induced by thiazolidinediones remain unclear. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In a 4-week run-in period, rosiglitazone, 4 mg twice daily, was added to a background anti-diabetic therapy in 260 South Indian patients with type 2 diabetes mellitus. Patients with PV expansion (absolute reduction in hematocrit in run-in, ≥1.5 percentage points) entered a randomized, placebo-controlled study to evaluate effects of amiloride and spironolactone on attenuating rosiglitazone-induced fluid retention. Primary endpoint was change in hematocrit in each diuretic group versus placebo (control group). RESULTS Of the 260 patients, 70% (n=180) had PV expansion. These 180 patients (70% male; mean age, 47.8 years [range, 30-80 years]) were randomly assigned to rosiglitazone, 4 mg twice daily, plus spironolactone, 50 mg once daily; rosiglitazone, 4 mg twice daily, plus amiloride, 10 mg once daily; or rosiglitazone, 4 mg twice daily, plus placebo for 24 weeks. Hematocrit continued to decrease significantly in control and spironolactone groups (mean absolute change, -1.2 [P=0.01] and -0.7 [P=0.02] percentage points, respectively), suggesting continued PV expansion. No change occurred with amiloride (mean change, 0.0 percentage points). Amiloride, but not spironolactone, was superior to control (mean hematocrit difference [95% confidence interval] relative to control, 1.27 [0.21-2.55] and 0.49 [-0.79-1.77] percentage points [P=0.04 and P=0.61], respectively). CONCLUSIONS Prevalence of rosiglitazone-induced fluid retention in South Indian patients with type 2 diabetes is high. Amiloride, a direct ENaC blocker, but not spironolactone, prevented protracted fluid retention in these patients.
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Affiliation(s)
- Vijay Viswanathan
- Department of Diabetes, M.V. Hospital for Diabetes and Prof M. Viswanathan Diabetes Research Centre, Chennai, India
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Seki G, Endo Y, Suzuki M, Yamada H, Horita S, Fujita T. Role of renal proximal tubule transport in thiazolidinedione-induced volume expansion. World J Nephrol 2012; 1:146-50. [PMID: 24175252 PMCID: PMC3782215 DOI: 10.5527/wjn.v1.i5.146] [Citation(s) in RCA: 9] [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: 08/09/2011] [Revised: 05/30/2012] [Accepted: 09/25/2012] [Indexed: 02/06/2023] Open
Abstract
Thiazolidinediones (TZDs), pharmacological activators of peroxisome-proliferator-activated receptors γ (PPARγ), significantly improve insulin resistance and lower plasma glucose concentrations. However, the use of TZDs is associated with plasma volume expansion, the mechanism of which has been a matter of controversy. Originally, PPARγ-mediated enhanced transcription of the epithelial Na channel (ENaC) γ subunit was thought to play a central role in TZD-induced volume expansion. However, later studies suggested that the activation of ENaC alone could not explain TZD-induced volume expansion. We have recently shown that TZDs rapidly stimulate sodium-coupled bicarbonate absorption from renal proximal tubule (PT) in vitro and in vivo. TZD-induced transport stimulation was dependent on PPARγ/Src/EGFR/ERK, and observed in rat, rabbit and human. However, this stimulation was not observed in mouse PTs where Src/EGFR is constitutively activated. Analysis in mouse embryonic fibroblast cells confirmed the existence of PPARγ/Src-dependent non-genomic signaling, which requires the ligand binding ability but not the transcriptional activity of PPARγ. The TZD-induced enhancement of association between PPARγ and Src supports an obligatory role for Src in this signaling. These results support the view that TZD-induced volume expansion is multifactorial. In addition to the PPARγ-dependent enhanced expression of the sodium transport system(s) in distal nephrons, the PPARγ-dependent non-genomic stimulation of renal proximal transport may be also involved in TZD-induced volume expansion.
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Affiliation(s)
- George Seki
- George Seki, Yoko Endo, Masashi Suzuki, Hideomi Yamada, Shoko Horita, Toshiro Fujita, Department of Internal Medicine, Faculty of Medicine, University of Tokyo, 7-3-1 Bunkyo-ku, Hongo, Tokyo 113-0033, Japan
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Bugaj V, Sansom SC, Wen D, Hatcher LI, Stockand JD, Mironova E. Flow-sensitive K+-coupled ATP secretion modulates activity of the epithelial Na+ channel in the distal nephron. J Biol Chem 2012; 287:38552-8. [PMID: 23002235 DOI: 10.1074/jbc.m112.408476] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The epithelial Na(+) channel (ENaC) in the aldosterone-sensitive distal nephron (ASDN) is under tonic inhibition by a local purinergic signaling system responding to changes in dietary sodium intake. Normal BK(Ca) channel function is required for flow-sensitive ATP secretion in the ASDN. We tested here whether ATP secreted through connexin channels in a coupled manner with K(+) efflux through BK(Ca) channels is required for inhibitory purinergic regulation of ENaC in response to increases in sodium intake. Inhibition of connexin channels relieves purinergic inhibition of ENaC. Deletion of the BK-β4 regulatory subunit, which is required for normal BK(Ca) channel function and flow-sensitive ATP secretion in the ASDN, suppresses increases in urinary ATP in response to increases in sodium intake. As a consequence, ENaC activity, particularly in the presence of high sodium intake, is inappropriately elevated in BK-β4 null mice. ENaC in BK-β4 null mice, however, responds normally to exogenous ATP, indicating that increases in activity do not result from end-organ resistance but rather from lowered urinary ATP. Consistent with this, disruption of purinergic regulation increases ENaC activity in wild type but not BK-β4 null mice. Consequently, sodium excretion is impaired in BK-β4 null mice. These results demonstrate that the ATP secreted in the ASDN in a BK(Ca) channel-dependent manner is physiologically available for purinergic inhibition of ENaC in response to changes in sodium homeostasis. Impaired sodium excretion resulting form loss of normal purinergic regulation of ENaC in BK-β4 null mice likely contributes to their elevated blood pressure.
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Affiliation(s)
- Vladislav Bugaj
- Department of Physiology, University of Texas Health Sciences Center, San Antonio, Texas 78229, USA
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Abstract
Cellular release of nucleotides is of physiological importance to regulate and maintain cell function and integrity. Also in the tubular and collecting duct system of the kidney, nucleotides are released in response to changes in cell volume or luminal flow rate and act in a paracrine and autocrine way on basolateral and luminal P2Y receptors. Recent studies using gene knockout mice assigned a prominent role to G protein-coupled P2Y(2) receptors, which are activated by both ATP and UTP. The antidiuretic hormone, arginine-vasopressin (AVP), and possibly an increase in collecting duct cell volume induce ATP release. The subsequent activation of P2Y(2) receptors inhibits AVP-induced cAMP formation and water reabsorption, which stabilizes cell volume and facilitates water excretion. An increase in NaCl intake enhances luminal release of ATP and UTP in the aldosterone-sensitive distal nephron which by activating apical P2Y(2) receptors and phospholipase C lowers the open probability of the epithelial sodium channel ENaC, thereby facilitating sodium excretion. Thus, the renal ATP/UTP/P2Y(2) receptor system not only serves to preserve cell volume and integrity but is also regulated by stimuli that derive from body NaCl homeostasis. The system also inhibits ENaC activity during aldosterone escape, i.e. when sodium reabsorption via ENaC is inappropriately high. The P2Y(2) receptor tone inhibits the expression and activity of the Na-K-2Cl cotransporter NKCC2 in the thick ascending limb and mediates vasodilation. While the role of other P2Y receptors in the kidney is less clear, the ATP/UTP/P2Y(2) receptor system regulates NaCl and water homeostasis and blood pressure.
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Affiliation(s)
- Volker Vallon
- Department of Medicine, University of California San Diego, San Diego, CA 92161, USA; VA San Diego Healthcare System, San Diego California, San Diego, CA 92161, USA; Department of Pharmacology, University of California San Diego, La Jolla, CA 92093, USA
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Suarez PE, Rodriguez EG, Soundararajan R, Mérillat AM, Stehle JC, Rotman S, Roger T, Voirol MJ, Wang J, Gross O, Pétrilli V, Nadra K, Wilson A, Beermann F, Pralong FP, Maillard M, Pearce D, Chrast R, Rossier BC, Hummler E. The glucocorticoid-induced leucine zipper (gilz/Tsc22d3-2) gene locus plays a crucial role in male fertility. Mol Endocrinol 2012; 26:1000-13. [PMID: 22556341 DOI: 10.1210/me.2011-1249] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The glucocorticoid-induced leucine zipper (Tsc22d3-2) is a widely expressed dexamethasone-induced transcript that has been proposed to be important in immunity, adipogenesis, and renal sodium handling based on in vitro studies. To address its function in vivo, we have used Cre/loxP technology to generate mice deficient for Tsc22d3-2. Male knockout mice were viable but surprisingly did not show any major deficiencies in immunological processes or inflammatory responses. Tsc22d3-2 knockout mice adapted to a sodium-deprived diet and to water deprivation conditions but developed a subtle deficiency in renal sodium and water handling. Moreover, the affected animals developed a mild metabolic phenotype evident by a reduction in weight from 6 months of age, mild hyperinsulinemia, and resistance to a high-fat diet. Tsc22d3-2-deficient males were infertile and exhibited severe testis dysplasia from postnatal d 10 onward with increases in apoptotic cells within seminiferous tubules, an increased number of Leydig cells, and significantly elevated FSH and testosterone levels. Thus, our analysis of the Tsc22d3-2-deficient mice demonstrated a previously uncharacterized function of glucocorticoid-induced leucine zipper protein in testis development.
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Affiliation(s)
- Philippe Emmanuel Suarez
- Departments of Pharmacology and Toxicology, University of Lausanne, CH-1005 Lausanne, Switzerland
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Cariou B, Charbonnel B, Staels B. Thiazolidinediones and PPARγ agonists: time for a reassessment. Trends Endocrinol Metab 2012; 23:205-15. [PMID: 22513163 DOI: 10.1016/j.tem.2012.03.001] [Citation(s) in RCA: 299] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 03/05/2012] [Accepted: 03/06/2012] [Indexed: 12/20/2022]
Abstract
Thiazolidinediones (TZDs) are anti-diabetic drugs that act as insulin sensitizers and are used in the management of type 2 diabetes mellitus. TZDs, which are ligands for the transcription factor peroxisome proliferator-activated receptor PPARγ, have a wide spectrum of action, including modulation of glucose and lipid homeostasis, inflammation, atherosclerosis, bone remodeling and cell proliferation. Randomized clinical trials have demonstrated the efficacy and durability of the anti-hyperglycemic action of TZDs, and have suggested that the TZD pioglitazone also exerts cardioprotective action. However, the clinical use of TZDs is limited by the occurrence of several adverse events, including body-weight gain, congestive heart failure, bone fractures and possibly bladder cancer. Therefore, there is an unmet need for the development of new safer PPARγ-modulating drugs.
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Affiliation(s)
- Bertrand Cariou
- Unité Mixte de Recherche 1087, Institut National de la Santé et de la Recherche Médicale (INSERM), Nantes 44000, France.
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Intrinsic control of sodium excretion in the distal nephron by inhibitory purinergic regulation of the epithelial Na(+) channel. Curr Opin Nephrol Hypertens 2012; 21:52-60. [PMID: 22143248 DOI: 10.1097/mnh.0b013e32834db4a0] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW This review summarizes the new evidence for an intrinsic control system in the aldosterone-sensitive distal nephron in which purinergic signaling regulates sodium transport and governs renal sodium excretion. RECENT FINDINGS Electrophysiological studies identify epithelial Na(+) channels (ENaC) as final effectors of purinergic signaling via P2Y(2) receptors in the distal nephron. Inhibition of ENaC by autocrine/paracrine purinergic signaling reduces sodium reabsorption allowing an appropriately graded pressure-natriuresis response when delivery of sodium to the distal nephron is high. Disruption of this intrinsic control mechanism decreases sodium excretion and therefore has a prohypertensive effect. Because purinergic inhibition of ENaC is tonic yet submaximal, its enhancement increases sodium excretion and therefore has an antihypertensive action. SUMMARY Purinergic inhibitory regulation of ENaC is a key component of an intrinsic control system that enables the distal nephron to respond appropriately to the delivered load of sodium. This control system is physiologically important and functions in parallel with extrinsic control by the renin-angiotensin-aldosterone system, enabling sodium excretion to keep pace with sodium intake, especially when intake is high, and thereby maintaining arterial blood pressure. Disruption of intrinsic control of sodium transport by the distal nephron likely contributes to diseases such as arterial hypertension.
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40
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Borsting E, Cheng VPC, Glass CK, Vallon V, Cunard R. Peroxisome proliferator-activated receptor-γ agonists repress epithelial sodium channel expression in the kidney. Am J Physiol Renal Physiol 2011; 302:F540-51. [PMID: 22169011 DOI: 10.1152/ajprenal.00306.2011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Thiazolidinediones (TZDs), known as peroxisome proliferator-activated receptor (PPAR) agonists, are used to treat type 2 diabetes. However, ∼5% of patients experience the treatment-limiting side effect of edema. Studies have implicated activation of the epithelial sodium channel (ENaC) as a cause of TZD-induced fluid retention, although there have been conflicting reports. The goal of this study was to resolve the role of PPARγ in control of ENaC isoforms in the kidney. Herein, we demonstrate in mice that rosiglitazone (RGZ), a PPARγ ligand, increases body weight and abdominal fat pad fluid content and reduces hematocrit. Seven days of RGZ decreases ENaCα and ENaCβ mRNA and ENaCγ protein expression in the kidney cortex, and acute treatment for 5 h with pioglitazone, another potent TZD, does not increase renal ENaC isoform mRNA or protein expression. Pioglitazone also decreases ENaCα and ENaCγ mRNA expression in a cortical collecting duct cell line. As no direct transcriptional studies had been conducted, we examined the PPARγ-dependent regulation of ENaC. Pioglitazone represses ENaCγ promoter activity, and this repression is partially relieved by inhibition of protein synthesis. Chromatin immunoprecipitation assays revealed that repression is associated with a decrease in histone H4K5 acetylation at the proximal ENaCγ promoter. In summary, TZDs do not increase ENaC mRNA expression in the kidney, and in fact repress the ENaCγ promoter via an indirect transcriptional mechanism.
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Affiliation(s)
- Emily Borsting
- Research and Medicine Services, Div. of Nephrology, Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA
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41
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Palmer LG, Patel A, Frindt G. Regulation and dysregulation of epithelial Na+ channels. Clin Exp Nephrol 2011; 16:35-43. [PMID: 22038262 DOI: 10.1007/s10157-011-0496-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 03/25/2011] [Indexed: 12/15/2022]
Affiliation(s)
- Lawrence G Palmer
- Department of Physiology and Biophysics, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA.
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42
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Bugaj V, Mironova E, Kohan DE, Stockand JD. Collecting duct-specific endothelin B receptor knockout increases ENaC activity. Am J Physiol Cell Physiol 2011; 302:C188-94. [PMID: 21918182 DOI: 10.1152/ajpcell.00301.2011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Collecting duct (CD)-derived endothelin-1 (ET-1) acting via endothelin B (ETB) receptors promotes Na(+) excretion. Compromise of ET-1 signaling or ETB receptors in the CD cause sodium retention and increase blood pressure. Activity of the epithelial Na(+) channel (ENaC) is limiting for Na(+) reabsorption in the CD. To test for ETB receptor regulation of ENaC, we combined patch-clamp electrophysiology with CD-specific knockout (KO) of endothelin receptors. We also tested how ET-1 signaling via specific endothelin receptors influences ENaC activity under differing dietary Na(+) regimens. ET-1 significantly decreased ENaC open probability in CD isolated from wild-type (WT) and CD ETA KO mice but not CD ETB KO and CD ETA/B KO mice. ENaC activity in WT and CD ETA but not CD ETB and CD ETA/B KO mice was inversely related to dietary Na(+) intake. ENaC activity in CD ETB and CD ETA/B KO mice tended to be elevated under all dietary Na(+) regimens compared with WT and CD ETA KO mice, reaching significance with high (2%) Na(+) feeding. These results show that the bulk of ET-1 inhibition of ENaC activity is mediated by the ETB receptor. In addition, they could explain the Na(+) retention and elevated blood pressure observed in CD ET-1 KO, CD ETB KO, and CD ETA/B KO mice consistent with ENaC regulation by ET-1 via ETB receptors contributing to the antihypertensive and natriuretic effects of the local endothelin system in the mammalian CD.
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Affiliation(s)
- Vladislav Bugaj
- Department of Physiology, University of Texas Health Sciences Center, San Antonio, Texas 78229, USA
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Vallon V, Rieg T. Regulation of renal NaCl and water transport by the ATP/UTP/P2Y2 receptor system. Am J Physiol Renal Physiol 2011; 301:F463-75. [PMID: 21715471 DOI: 10.1152/ajprenal.00236.2011] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Extracellular nucleotides (e.g., ATP) activate ionotropic P2X and metabotropic P2Y receptors in the plasma membrane to regulate and maintain cell function and integrity. This includes the renal tubular and collecting duct system, where the locally released nucleotides act in a paracrine and autocrine way to regulate transport of electrolytes and water and maintain cell volume. A prominent role has been assigned to Gq-coupled P2Y(2) receptors, which are typically activated by both ATP and UTP. Studies in gene knockout mice revealed an antihypertensive activity of P2Y(2) receptors that is linked to vasodilation and an inhibitory influence on renal salt reabsorption. Flow induces apical ATP release in the thick ascending limb, and first evidence indicates an inhibitory influence of P2Y(2) receptor tone on the expression and activity of the Na-K-2Cl cotransporter NKCC2 in this segment. The apical ATP/UTP/P2Y(2) receptor system in the connecting tubule/cortical collecting duct mediates the inhibitory effect of dietary salt on the open probability of the epithelial sodium channel ENaC and inhibits ENaC activity during aldosterone escape. Connexin 30 has been implicated in the luminal release of the ATP involved in the regulation of ENaC. An increase in collecting duct cell volume in response to manipulating water homeostasis increases ATP release. The subsequent activation of P2Y(2) receptors inhibits vasopressin-induced cAMP formation and water reabsorption, which facilitates water excretion and stabilizes cell volume. Thus recent studies have established the ATP/UTP/P2Y(2) receptor system as a relevant regulator of renal salt and water homeostasis and blood pressure regulation. The pathophysiological relevance and therapeutic potential remains to be determined, but dual effects of P2Y(2) receptor activation on both the vasculature and renal salt reabsorption implicate these receptors as potential therapeutic targets in hypertension.
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Affiliation(s)
- Volker Vallon
- Dept. of Medicine, Univ. of California San Diego, 92161, USA.
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Zuo Y, Yang HC, Potthoff SA, Najafian B, Kon V, Ma LJ, Fogo AB. Protective effects of PPARγ agonist in acute nephrotic syndrome. Nephrol Dial Transplant 2011; 27:174-81. [PMID: 21565943 DOI: 10.1093/ndt/gfr240] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Peroxisome proliferator-activated receptor gamma (PPARγ) agonists have beneficial effects on renal structure and function in models of diabetes and chronic kidney diseases. However, the increased incidence of weight gain and edema potentially limits their usefulness. We studied an acute minimal-change disease-like nephrotic syndrome model to assess effects of PPARγ agonist on acute podocyte injury and effects on fluid homeostasis. METHODS Acute podocyte injury and nephrotic syndrome were induced by puromycin aminonucleoside (PAN) injection in rats. RESULTS PPARγ agonist, given at the time or after, but not before PAN, reduced proteinuria, restored synaptopodin, decreased desmin and trended to improve foot process effacement. There was no significant difference in glomerular filtration, effective circulating volume, blood pressure or fractional sodium excretion. PAN-injured podocytes had decreased PPARγ, less nephrin and α-actinin-4, more apoptosis and reduced phosphorylated Akt. In PAN-injured cultured podocytes, PPARγ agonist also reversed abnormalities only when given simultaneously or after injury. CONCLUSIONS These results show that PPARγ agonist has protective effects on podocytes in acute nephrotic syndrome without deleterious effects on fluid homeostasis. PPARγ agonist-induced decrease in proteinuria in acute nephrotic syndrome is dependent at least partially on regulation of peroxisome proliferator-response element-sensitive gene expression such as α-actinin-4 and nephrin and the restoration of podocyte structure.
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Affiliation(s)
- Yiqin Zuo
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN, USA
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Thiazolidinediones enhance sodium-coupled bicarbonate absorption from renal proximal tubules via PPARγ-dependent nongenomic signaling. Cell Metab 2011; 13:550-61. [PMID: 21531337 DOI: 10.1016/j.cmet.2011.02.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 01/10/2011] [Accepted: 02/17/2011] [Indexed: 01/09/2023]
Abstract
Thiazolidinediones (TZDs) improve insulin resistance by activating a nuclear hormone receptor, peroxisome proliferator-activated receptor γ (PPARγ). However, the use of TZDs is associated with plasma volume expansion through a mechanism that remains to be clarified. Here we showed that TZDs rapidly stimulate sodium-coupled bicarbonate absorption from the renal proximal tubule in vitro and in vivo. TZD-induced transport stimulation is dependent on PPARγ-Src-EGFR-ERK and observed in rat, rabbit and human, but not in mouse proximal tubules where Src-EGFR is constitutively activated. The existence of PPARγ-Src-dependent nongenomic signaling, which requires the ligand-binding ability, but not the transcriptional activity of PPARγ, is confirmed in mouse embryonic fibroblast cells. The enhancement of the association between PPARγ and Src by TZDs supports an indispensable role of Src in this signaling. These results suggest that the PPARγ-dependent nongenomic stimulation of renal proximal transport is also involved in TZD-induced volume expansion.
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Goltsman I, Wang X, LaVallie ER, DiBlasio-Smith EA, Ovcharenko E, Hoffman A, Abassi Z, Feuerstein GZ, Winaver J. Effects of Chronic Rosiglitazone Treatment on Renal Handling of Salt and Water in Rats With Volume-Overload Congestive Heart Failure. Circ Heart Fail 2011; 4:345-54. [DOI: 10.1161/circheartfailure.110.960179] [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] [Indexed: 11/16/2022]
Abstract
Background—
The side effects of fluid retention and edema of the thiazolidinedione (TZD) class of peroxisome proliferator-activated receptor-γ agonists limit their use in patients with congestive heart failure (CHF). The present study aims to explore whether chronic treatment with the TZD compound rosiglitazone (RGZ) is associated with worsening of salt and water retention in male Sprague-Dawley rats with aorto-caval fistula, an experimental model of volume-overload CHF.
Methods and Results—
The effects of oral RGZ (30 mg/kg per day for 4 weeks) in CHF rats on plasma volume, cumulative sodium excretion, renal expression of Na
+
channels and transporters, and selected biomarkers of CHF were compared with those in CHF rats and sham-operated control rats treated with vehicle only (n=7 to 10). Additionally, the response to acute saline loading (3.5% of body weight) was evaluated after 2 weeks of treatment by renal clearance methodology. Chronic RGZ treatment caused no further increase in plasma volume compared with vehicle-treated CHF rats. Moreover, no increase in renal expression of Na
+
transport-linked channels/transporters was observed in response to RGZ. Cumulative sodium excretion was enhanced in CHF rats after RGZ and by another TZD compound, pioglitazone. In response to saline loading, RGZ-treated animals displayed a higher natriuretic/diuretic response than did vehicle-treated rats. Chronic RGZ treatment was not associated with any deterioration in selected biomarkers of CHF, whereas indices of cardiac hypertrophy and blood pressure were improved.
Conclusions—
Chronic RGZ treatment was not associated with worsening of fluid retention or cardiac status in rats with experimental volume-overload CHF. Rather, RGZ appeared to improve renal handling of salt and water in rats with CHF.
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Affiliation(s)
- Ilia Goltsman
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
| | - Xinkang Wang
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
| | - Edward R. LaVallie
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
| | - Elizabeth A. DiBlasio-Smith
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
| | - Elena Ovcharenko
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
| | - Aaron Hoffman
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
| | - Zaid Abassi
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
| | - Giora Z. Feuerstein
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
| | - Joseph Winaver
- From the Department of Physiology and Biophysics, Faculty of Medicine, Technion-IIT, Haifa, Israel (I.G., E.O., A.H., Z.A., J.W.); Translational Medicine, Pfizer, Collegeville, PA (X.W., G.Z.F.); and Biological Technologies, Pfizer, Cambridge, MA (E.R.L., E.A.D.-S.)
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Rennings AJ, Russel FG, Li Y, Deen PM, Masereeuw R, Tack CJ, Smits P. Preserved Response to Diuretics in Rosiglitazone-Treated Subjects With Insulin Resistance: A Randomized Double-Blind Placebo-Controlled Crossover Study. Clin Pharmacol Ther 2011; 89:587-94. [DOI: 10.1038/clpt.2010.360] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mironova E, Peti-Peterdi J, Bugaj V, Stockand JD. Diminished paracrine regulation of the epithelial Na+ channel by purinergic signaling in mice lacking connexin 30. J Biol Chem 2011; 286:1054-60. [PMID: 21075848 PMCID: PMC3020712 DOI: 10.1074/jbc.m110.176552] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 10/21/2010] [Indexed: 01/10/2023] Open
Abstract
We tested whether ATP release through Connexin 30 (Cx30) is part of a local purinergic regulatory system intrinsic to the aldosterone-sensitive distal nephron (ASDN) important for proper control of sodium excretion; if changes in sodium intake influence ATP release via Cx30; and if this allows a normal ENaC response to changes in systemic sodium levels. In addition, we define the consequences of disrupting ATP regulation of ENaC in Cx30(-/-) mice. Urinary ATP levels in wild-type mice increase with sodium intake, being lower and less dependent on sodium intake in Cx30(-/-) mice. Loss of inhibitory ATP regulation causes ENaC activity to be greater in Cx30(-/-) versus wild-type mice, particularly with high sodium intake. This results from compromised ATP release rather than end-organ resistance: ENaC in Cx30(-/-) mice responds to exogenous ATP. Thus, loss of paracrine ATP feedback regulation of ENaC in Cx30(-/-) mice disrupts normal responses to changes in sodium intake. Consequently, ENaC is hyperactive in Cx30(-/-) mice lowering sodium excretion particularly during increases in sodium intake. Clamping mineralocorticoids high in Cx30(-/-) mice fed a high sodium diet causes a marked decline in renal sodium excretion. This is not the case in wild-type mice, which are capable of undergoing aldosterone-escape. This loss of the ability of ENaC to respond to changes in sodium levels contributes to salt-sensitive hypertension in Cx30(-/-) mice.
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Affiliation(s)
- Elena Mironova
- From the Department of Physiology, University of Texas Health Science Center, San Antonia, Texas 78229-3900 and
| | - Janos Peti-Peterdi
- the Department of Physiology and Biophysics, University of Southern California, Los Angeles, California 90089
| | - Vladislav Bugaj
- From the Department of Physiology, University of Texas Health Science Center, San Antonia, Texas 78229-3900 and
| | - James D. Stockand
- From the Department of Physiology, University of Texas Health Science Center, San Antonia, Texas 78229-3900 and
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49
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Christensen BM, Zuber AM, Loffing J, Stehle JC, Deen PMT, Rossier BC, Hummler E. alphaENaC-mediated lithium absorption promotes nephrogenic diabetes insipidus. J Am Soc Nephrol 2010; 22:253-61. [PMID: 21051735 DOI: 10.1681/asn.2010070734] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Lithium-induced nephrogenic diabetes insipidus (NDI) is accompanied by polyuria, downregulation of aquaporin 2 (AQP2), and cellular remodeling of the collecting duct (CD). The amiloride-sensitive epithelial sodium channel (ENaC) is a likely candidate for lithium entry. Here, we subjected transgenic mice lacking αENaC specifically in the CD (knockout [KO] mice) and littermate controls to chronic lithium treatment. In contrast to control mice, KO mice did not markedly increase their water intake. Furthermore, KO mice did not demonstrate the polyuria and reduction in urine osmolality induced by lithium treatment in the control mice. Lithium treatment reduced AQP2 protein levels in the cortex/outer medulla and inner medulla (IM) of control mice but only partially reduced AQP2 levels in the IM of KO mice. Furthermore, lithium induced expression of H(+)-ATPase in the IM of control mice but not KO mice. In conclusion, the absence of functional ENaC in the CD protects mice from lithium-induced NDI. These data support the hypothesis that ENaC-mediated lithium entry into the CD principal cells contributes to the pathogenesis of lithium-induced NDI.
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Affiliation(s)
- Birgitte Mønster Christensen
- Water and Salt Research Center, Department of Anatomy, Aarhus University, Wilhelm Meyers Allé 3, 8000 Aarhus C, Denmark.
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50
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Rieg T, Tang T, Murray F, Schroth J, Insel PA, Fenton RA, Hammond HK, Vallon V. Adenylate cyclase 6 determines cAMP formation and aquaporin-2 phosphorylation and trafficking in inner medulla. J Am Soc Nephrol 2010; 21:2059-68. [PMID: 20864687 DOI: 10.1681/asn.2010040409] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Arginine vasopressin (AVP) enhances water reabsorption in the renal collecting duct by vasopressin V₂ receptor (V₂R)-mediated activation of adenylyl cyclase (AC), cAMP-promoted phosphorylation of aquaporin-2 (AQP2), and increased abundance of AQP2 on the apical membrane. Multiple isoforms of adenylate cyclase exist, and the roles of individual AC isoforms in water homeostasis are not well understood. Here, we found that levels of AC6 mRNA, the most highly expressed AC isoform in the inner medulla, inversely correlate with fluid intake. Moreover, mice lacking AC6 had lower levels of inner medullary cAMP, reduced abundance of phosphorylated AQP2 (at both serine-256 and serine-269), and lower urine osmolality than wild-type mice. Water deprivation or administration of the V₂R agonist dDAVP did not increase urine osmolality of AC6-deficient mice to the levels of wild-type mice. Furthermore, AC6-deficient mice lacked dDAVP-promoted inner medullary cAMP formation and phosphorylation of serine-269 and had attenuated increases in both phosphorylation of serine-256 and apical membrane AQP2 trafficking. In summary, AC6 expression determines inner medullary cAMP formation and AQP2 phosphorylation and trafficking, the absence of which causes nephrogenic diabetes insipidus.
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Affiliation(s)
- Timo Rieg
- Department of Medicine, Division of Nephrology/Hypertension, University of California San Diego and VA San Diego Healthcare System, 3350 La Jolla Village Drive (9151), San Diego, CA 92161, USA.
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