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Srimai N, Tonum K, Soodvilai S. Activation of farnesoid X receptor retards expansion of renal collecting duct cell-derived cysts via inhibition of CFTR-mediated Cl - secretion. Am J Physiol Renal Physiol 2024; 326:F600-F610. [PMID: 38299213 DOI: 10.1152/ajprenal.00363.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 01/12/2024] [Accepted: 01/29/2024] [Indexed: 02/02/2024] Open
Abstract
The transcription factor farnesoid X receptor (FXR) regulates energy metabolism. Specifically, FXR functions to regulate cystic fibrosis transmembrane conductance regulator (CFTR)-mediated Cl- secretion in intestinal epithelial cells. Therefore, this study aimed to investigate the role of FXR in CFTR-mediated Cl- secretion in renal tubular cells and to further elucidate its effects on renal cyst formation and growth. CFTR-mediated Cl- transport was evaluated via short-circuit current (ISC) measurements in Madin-Darby canine kidney (MDCK) cell monolayers and primary rat inner medullary collecting duct cells. The role of FXR in renal cyst formation and growth was determined by the MDCK cell-derived cyst model. Incubation with synthesized (GW4064) and endogenous (CDCA) FXR ligands reduced CFTR-mediated Cl- secretion in a concentration- and time-dependent manner. The inhibitory effect of FXR ligands was not due to the result of reduced cell viability and was attenuated by cotreatment with an FXR antagonist. FXR activation significantly decreased CFTR protein but not its mRNA. In addition, FXR activation inhibited CFTR-mediated Cl- secretion in primary renal collecting duct cells. FXR activation decreased ouabain-sensitive ISC without altering Na+-K+-ATPase mRNA and protein levels. Furthermore, FXR activation significantly reduced the number of cysts and renal cyst expansion. These inhibitory effects were correlated with a decrease in the expression of protein synthesis regulators mammalian target of rapamycin/S6 kinase. This study shows that FXR activation inhibits Cl- secretion in renal cells via inhibition of CFTR expression and retards renal cyst formation and growth. The discoveries point to a physiological role of FXR in the regulation of CFTR and a potential therapeutic application in polycystic kidney disease treatment.NEW & NOTEWORTHY The present study reveals that farnesoid X receptor (FXR) activation reduces microcyst formation and enlargement. This inhibitory effect of FXR activation is involved with decreased cell proliferation and cystic fibrosis transmembrane conductance regulator-mediated Cl- secretion in renal collecting duct cells. FXR might represent a novel target for the treatment of autosomal dominant polycystic kidney disease.
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Affiliation(s)
- Nipitpon Srimai
- Research Center of Transport Protein for Medical Innovation, Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Kanlayanee Tonum
- Department of Physiology, Faculty of Pharmacy, Mahidol University, Bangkok, Thailand
| | - Sunhapas Soodvilai
- Research Center of Transport Protein for Medical Innovation, Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
- Excellent Center for Drug Discovery, Mahidol University, Bangkok, Thailand
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2
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Oto OA, Atwood DJ, Chaudhary A, He Z, Li AS, Wempe MF, Edelstein CL. Metformin does not slow cyst growth in the PCK rat model of polycystic kidney disease. Physiol Rep 2023; 11:e15776. [PMID: 37653564 PMCID: PMC10471794 DOI: 10.14814/phy2.15776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/01/2023] [Accepted: 07/03/2023] [Indexed: 09/02/2023] Open
Abstract
Metformin (MET) has the potential to activate p-AMPK and block mTORC1-induced proliferation of tubular cells in PKD kidneys. The aim of this study was to determine the effects of MET on cyst growth, kidney function, AMPK and mTOR signaling, and lactate levels in male PCK rats, a Pkhd1 gene mutation model of human autosomal recessive polycystic kidney disease (ARPKD). MET 300 mg/kg/day IP from days 28 to 84 of age resulted in a mean serum metformin level that was 10 times the upper limit of therapeutic, no effect on cyst indices, nephrotoxicity, and increased serum lactate. MET 150 mg/kg resulted in a therapeutic serum metformin level but had no effect on kidney weight, cyst indices, kidney function, or mTOR and autophagy proteins. In summary, a standard dose of MET was ineffective in reducing PKD, did not activate p-AMPK or suppress mTOR and the higher dose resulted in increased lactate levels and nephrotoxicity. In conclusion, the study dampens enthusiasm for human studies of MET in PKD. Doubling the metformin dose resulted in a 10-fold increase in mean blood levels and toxicity suggesting that the dosage range between therapeutic and toxic is narrow.
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Affiliation(s)
- Ozgur A. Oto
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Daniel J. Atwood
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Anjana Chaudhary
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Zhibin He
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Amy S. Li
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Michael F. Wempe
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical SciencesUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
| | - Charles L. Edelstein
- Division of Renal Diseases and HypertensionUniversity of Colorado Anschutz Medical CampusAuroraColoradoUSA
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3
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Bakaj I, Pocai A. Metabolism-based approaches for autosomal dominant polycystic kidney disease. Front Mol Biosci 2023; 10:1126055. [PMID: 36876046 PMCID: PMC9980902 DOI: 10.3389/fmolb.2023.1126055] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 02/06/2023] [Indexed: 02/18/2023] Open
Abstract
Autosomal Dominant Polycystic Kidney Disease (ADPKD) leads to end stage kidney disease (ESKD) through the development and expansion of multiple cysts throughout the kidney parenchyma. An increase in cyclic adenosine monophosphate (cAMP) plays an important role in generating and maintaining fluid-filled cysts because cAMP activates protein kinase A (PKA) and stimulates epithelial chloride secretion through the cystic fibrosis transmembrane conductance regulator (CFTR). A vasopressin V2 receptor antagonist, Tolvaptan, was recently approved for the treatment of ADPKD patients at high risk of progression. However additional treatments are urgently needed due to the poor tolerability, the unfavorable safety profile, and the high cost of Tolvaptan. In ADPKD kidneys, alterations of multiple metabolic pathways termed metabolic reprogramming has been consistently reported to support the growth of rapidly proliferating cystic cells. Published data suggest that upregulated mTOR and c-Myc repress oxidative metabolism while enhancing glycolytic flux and lactic acid production. mTOR and c-Myc are activated by PKA/MEK/ERK signaling so it is possible that cAMPK/PKA signaling will be upstream regulators of metabolic reprogramming. Novel therapeutics opportunities targeting metabolic reprogramming may avoid or minimize the side effects that are dose limiting in the clinic and improve on the efficacy observed in human ADPKD with Tolvaptan.
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Affiliation(s)
- Ivona Bakaj
- Cardiovascular and Metabolism, Janssen Research and Development, Spring House, PA, United States
| | - Alessandro Pocai
- Cardiovascular and Metabolism, Janssen Research and Development, Spring House, PA, United States
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4
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Hiratsuka K, Miyoshi T, Kroll KT, Gupta NR, Valerius MT, Ferrante T, Yamashita M, Lewis JA, Morizane R. Organoid-on-a-chip model of human ARPKD reveals mechanosensing pathomechanisms for drug discovery. SCIENCE ADVANCES 2022; 8:eabq0866. [PMID: 36129975 PMCID: PMC9491724 DOI: 10.1126/sciadv.abq0866] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 08/03/2022] [Indexed: 05/23/2023]
Abstract
Organoids serve as a novel tool for disease modeling in three-dimensional multicellular contexts. Static organoids, however, lack the requisite biophysical microenvironment such as fluid flow, limiting their ability to faithfully recapitulate disease pathology. Here, we unite organoids with organ-on-a-chip technology to unravel disease pathology and develop therapies for autosomal recessive polycystic kidney disease. PKHD1-mutant organoids-on-a-chip are subjected to flow that induces clinically relevant phenotypes of distal nephron dilatation. Transcriptomics discover 229 signal pathways that are not identified by static models. Mechanosensing molecules, RAC1 and FOS, are identified as potential therapeutic targets and validated by patient kidney samples. On the basis of this insight, we tested two U.S. Food and Drug Administration-approved and one investigational new drugs that target RAC1 and FOS in our organoid-on-a-chip model, which suppressed cyst formation. Our observations highlight the vast potential of organoid-on-a-chip models to elucidate complex disease mechanisms for therapeutic testing and discovery.
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Affiliation(s)
- Ken Hiratsuka
- Nephrology Division, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- John A. Paulson School of Engineering and Applied Sciences and Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Tomoya Miyoshi
- Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA, USA
| | - Katharina T. Kroll
- John A. Paulson School of Engineering and Applied Sciences and Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Navin R. Gupta
- Nephrology Division, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Harvard Stem Cell Institute (HSCI), Cambridge, MA, USA
| | - M. Todd Valerius
- Harvard Medical School, Boston, MA, USA
- Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Harvard Stem Cell Institute (HSCI), Cambridge, MA, USA
| | - Thomas Ferrante
- John A. Paulson School of Engineering and Applied Sciences and Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Michifumi Yamashita
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Jennifer A. Lewis
- John A. Paulson School of Engineering and Applied Sciences and Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Harvard Stem Cell Institute (HSCI), Cambridge, MA, USA
| | - Ryuji Morizane
- Nephrology Division, Massachusetts General Hospital, Boston, MA, USA
- Harvard Medical School, Boston, MA, USA
- John A. Paulson School of Engineering and Applied Sciences and Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Division of Renal Medicine, Brigham and Women’s Hospital, Boston, MA, USA
- Harvard Stem Cell Institute (HSCI), Cambridge, MA, USA
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Corkins ME, Krneta-Stankic V, Kloc M, Miller RK. Aquatic models of human ciliary diseases. Genesis 2021; 59:e23410. [PMID: 33496382 PMCID: PMC8593908 DOI: 10.1002/dvg.23410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/08/2021] [Accepted: 01/09/2021] [Indexed: 11/06/2022]
Abstract
Cilia are microtubule-based structures that either transmit information into the cell or move fluid outside of the cell. There are many human diseases that arise from malfunctioning cilia. Although mammalian models provide vital insights into the underlying pathology of these diseases, aquatic organisms such as Xenopus and zebrafish provide valuable tools to help screen and dissect out the underlying causes of these diseases. In this review we focus on recent studies that identify or describe different types of human ciliopathies and outline how aquatic organisms have aided our understanding of these diseases.
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Affiliation(s)
- Mark E. Corkins
- Department of Pediatrics, Pediatric Research Center, UTHealth McGovern Medical School, Houston Texas 77030
| | - Vanja Krneta-Stankic
- Department of Pediatrics, Pediatric Research Center, UTHealth McGovern Medical School, Houston Texas 77030
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genes & Development, Houston Texas 77030
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genetics & Epigenetics, Houston, Texas 77030
| | - Malgorzata Kloc
- Houston Methodist, Research Institute, Houston Texas 77030
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston Texas 77030
| | - Rachel K. Miller
- Department of Pediatrics, Pediatric Research Center, UTHealth McGovern Medical School, Houston Texas 77030
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Genetics & Epigenetics, Houston, Texas 77030
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston Texas 77030
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Program in Biochemistry & Cell Biology, Houston Texas 77030
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6
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Wang J, Chin D, Poon C, Mancino V, Pham J, Li H, Ho PY, Hallows KR, Chung EJ. Oral delivery of metformin by chitosan nanoparticles for polycystic kidney disease. J Control Release 2021; 329:1198-1209. [PMID: 33127449 PMCID: PMC7904655 DOI: 10.1016/j.jconrel.2020.10.047] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 10/20/2020] [Accepted: 10/22/2020] [Indexed: 12/15/2022]
Abstract
Nanoparticle drug delivery has many advantages over small molecule therapeutics, including reducing off-target side effects and increasing drug potency. However, many nanoparticles are administered parenterally, which is challenging for chronic diseases such as polycystic kidney disease (PKD), the most common hereditary disease worldwide in which patients need continuous treatment over decades. To address this clinical need, we present the development of nanoparticles synthesized from chitosan, a widely available polymer chosen for its ability to improve oral bioavailability. Specifically, we optimized the synthesis parameters of chitosan nanoparticles and demonstrate mucoadhesion and permeation across an intestinal barrier model in vitro. Furthermore, when administered orally to mice, ex vivo imaging of rhodamine-loaded chitosan nanoparticles showed significantly higher accumulation in the intestines compared to the free model drug, as well as 1.3 times higher serum area under the curve (AUC), demonstrating controlled release and improved serum delivery over 24 h. To test its utility for chronic diseases such as PKD, we loaded the candidate PKD drug, metformin, into chitosan nanoparticles, and upon oral administration to a PKD murine model (Pkd1fl/fl;Pax8-rtTA;Tet-O cre), a lower cyst burden was observed compared to free metformin, and was well tolerated upon repeated dosages. Blood urea nitrogen (BUN) and creatinine levels were similar to untreated mice, demonstrating kidney and biocompatibility health. Our study builds upon previous chitosan-based drug delivery approaches, and demonstrates a novel, oral nanoformulation for PKD.
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Affiliation(s)
- Jonathan Wang
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Deborah Chin
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Christopher Poon
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA
| | - Valeria Mancino
- Department of Medicine, Division of Nephrology and Hypertension, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; USC/UKRO Kidney Research Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Jessica Pham
- Department of Medicine, Division of Nephrology and Hypertension, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; USC/UKRO Kidney Research Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Hui Li
- Department of Medicine, Division of Nephrology and Hypertension, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; USC/UKRO Kidney Research Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Pei-Yin Ho
- Department of Medicine, Division of Nephrology and Hypertension, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; USC/UKRO Kidney Research Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Kenneth R Hallows
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA; Department of Medicine, Division of Nephrology and Hypertension, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; USC/UKRO Kidney Research Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Eun Ji Chung
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA; Department of Medicine, Division of Nephrology and Hypertension, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, USA; Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA; Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA, USA; Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA, USA; Bridge Institute, University of Southern California, Los Angeles, CA, USA.
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7
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El-Damanawi R, Lee M, Harris T, Cowley LB, Bond S, Pavey H, Sandford RN, Wilkinson IB, Karet Frankl FE, Hiemstra TF. High water vs. ad libitum water intake for autosomal dominant polycystic kidney disease: a randomized controlled feasibility trial. QJM 2020; 113:258-265. [PMID: 31665476 PMCID: PMC7133783 DOI: 10.1093/qjmed/hcz278] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 10/02/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Vasopressin stimulates cyst growth in autosomal dominant polycystic kidney disease (ADPKD) and is a key therapeutic target. Evaluation of high water intake as an alternative to pharmacological vasopressin blockade is supported by patients. However feasibility, safety and adherence-promoting strategies required to deliver this remain unknown. AIMS Assess the feasibility of a definitive randomized high water intake trial in ADPKD. METHODS In this prospective open-label randomized trial, adult ADPKD patients with eGFR ≥ 20 ml/min/1.73 m2 were randomized to prescribed high water (HW) intake targeting urine osmolality (UOsm) ≤270 mOsm/kg, or ad libitum (AW) intake (UOsm >300 mOsm/kg). Self-management strategies including home-monitoring of urine-specific gravity (USG) were employed to promote adherence. RESULTS We enrolled 42 participants, baseline median eGFR (HW 68.4 [interquartile range (IQR) 35.9-107.2] vs. AW 75.8 [IQR 59.0-111.0 ml/min/1.73 m2, P = 0.22) and UOsm (HW 353 [IQR 190-438] vs. AW 350 [IQR 240-452] mOsm/kg, P = 0.71) were similar between groups. After 8 weeks, 67% in the HW vs. 24% in AW group achieved UOsm ≤270 mOsm/kg, P = 0.001. HW group achieved lower UOsm (194 [IQR 190-438] vs. 379 [IQR 235-503] mOsm/kg, P = 0.01) and higher urine volumes (3155 [IQR 2270-4295] vs. 1920 [IQR 1670-2960] ml/day, P = 0.02). Two cases of hyponatraemia occurred in HW group. No acute GFR effects were detected. In total 79% (519/672) of USG were submitted and 90% (468/519) were within target. Overall, 17% withdrew during the study. CONCLUSION DRINK demonstrated successful recruitment and adherence leading to separation between treatment arms in primary outcomes. These findings suggest a definitive trial assessing the impact of high water on kidney disease progression in ADPKD is feasible.
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Affiliation(s)
- R El-Damanawi
- Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge
- Cambridge Clinical Trials Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge
| | - M Lee
- Division of Anaesthesia, Department of Medicine, University of Cambridge, Cambridge
| | - T Harris
- PKD Charity, 91 Royal College, London
| | - L B Cowley
- Cambridge Clinical Trials Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge
- Patient Led Research Hub, Cambridge NIHR Biomedical Research Centre, Cambridge
| | - S Bond
- Cambridge Clinical Trials Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge
| | - H Pavey
- Cambridge Clinical Trials Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge
| | - R N Sandford
- Department of Medical Genetics, University of Cambridge, Hills Road, Cambridge, UK
| | - I B Wilkinson
- Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge
- Cambridge Clinical Trials Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge
| | - F E Karet Frankl
- Department of Medical Genetics, University of Cambridge, Hills Road, Cambridge, UK
| | - T F Hiemstra
- Division of Experimental Medicine and Immunotherapeutics, Department of Medicine, University of Cambridge, Cambridge
- Cambridge Clinical Trials Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge
- Address correspondence to Dr T.F. Hiemstra, Cambridge Clinical Trials Unit, Box 401 Cambridge Biomedical Camp us, Hills Road, Cambridge CB2 0QQ, UK.
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8
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Nowak KL, Edelstein CL. Apoptosis and autophagy in polycystic kidney disease (PKD). Cell Signal 2019; 68:109518. [PMID: 31881325 DOI: 10.1016/j.cellsig.2019.109518] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/20/2019] [Accepted: 12/21/2019] [Indexed: 02/08/2023]
Abstract
Apoptosis in the cystic epithelium is observed in most rodent models of polycystic kidney disease (PKD) and in human autosomal dominant PKD (ADPKD). Apoptosis inhibition decreases cyst growth, whereas induction of apoptosis in the kidney of Bcl-2 deficient mice increases proliferation of the tubular epithelium and subsequent cyst formation. However, alternative evidence indicates that both induction of apoptosis as well as increased overall rates of apoptosis are associated with decreased cyst growth. Autophagic flux is suppressed in cell, zebra fish and mouse models of PKD and suppressed autophagy is known to be associated with increased apoptosis. There may be a link between apoptosis and autophagy in PKD. The mammalian target of rapamycin (mTOR), B-cell lymphoma 2 (Bcl-2) and caspase pathways that are known to be dysregulated in PKD, are also known to regulate both autophagy and apoptosis. Induction of autophagy in cell and zebrafish models of PKD results in suppression of apoptosis and reduced cyst growth supporting the hypothesis autophagy induction may have a therapeutic role in decreasing cyst growth, perhaps by decreasing apoptosis and proliferation in PKD. Future research is needed to evaluate the effects of direct autophagy inducers on apoptosis in rodent PKD models, as well as the cause and effect relationship between autophagy, apoptosis and cyst growth in PKD.
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Affiliation(s)
- Kristen L Nowak
- Division of Renal Diseases and Hypertension, Univ. of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Charles L Edelstein
- Division of Renal Diseases and Hypertension, Univ. of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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9
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Drug prioritization using the semantic properties of a knowledge graph. Sci Rep 2019; 9:6281. [PMID: 31000794 PMCID: PMC6472420 DOI: 10.1038/s41598-019-42806-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 03/28/2019] [Indexed: 02/01/2023] Open
Abstract
Compounds that are candidates for drug repurposing can be ranked by leveraging knowledge available in the biomedical literature and databases. This knowledge, spread across a variety of sources, can be integrated within a knowledge graph, which thereby comprehensively describes known relationships between biomedical concepts, such as drugs, diseases, genes, etc. Our work uses the semantic information between drug and disease concepts as features, which are extracted from an existing knowledge graph that integrates 200 different biological knowledge sources. RepoDB, a standard drug repurposing database which describes drug-disease combinations that were approved or that failed in clinical trials, is used to train a random forest classifier. The 10-times repeated 10-fold cross-validation performance of the classifier achieves a mean area under the receiver operating characteristic curve (AUC) of 92.2%. We apply the classifier to prioritize 21 preclinical drug repurposing candidates that have been suggested for Autosomal Dominant Polycystic Kidney Disease (ADPKD). Mozavaptan, a vasopressin V2 receptor antagonist is predicted to be the drug most likely to be approved after a clinical trial, and belongs to the same drug class as tolvaptan, the only treatment for ADPKD that is currently approved. We conclude that semantic properties of concepts in a knowledge graph can be exploited to prioritize drug repurposing candidates for testing in clinical trials.
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10
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Malekshahabi T, Khoshdel Rad N, Serra AL, Moghadasali R. Autosomal dominant polycystic kidney disease: Disrupted pathways and potential therapeutic interventions. J Cell Physiol 2019; 234:12451-12470. [PMID: 30644092 DOI: 10.1002/jcp.28094] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/07/2018] [Indexed: 12/18/2022]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a monogenic inherited renal cystic disease that occurs in different races worldwide. It is characterized by the development of a multitude of renal cysts, which leads to massive enlargement of the kidney and often to renal failure in adulthood. ADPKD is caused by a mutation in PKD1 or PKD2 genes encoding the proteins polycystin-1 and polycystin-2, respectively. Recent studies showed that cyst formation and growth result from deregulation of multiple cellular pathways like proliferation, apoptosis, metabolic processes, cell polarity, and immune defense. In ADPKD, intracellular cyclic adenosine monophosphate (cAMP) promotes cyst enlargement by stimulating cell proliferation and transepithelial fluid secretion. Several interventions affecting many of these defective signaling pathways have been effective in animal models and some are currently being tested in clinical trials. Moreover, the stem cell therapy can improve nephropathies and according to studies were done in this field, can be considered as a hopeful therapeutic approach in future for PKD. This study provides an in-depth review of the relevant molecular pathways associated with the pathogenesis of ADPKD and their implications in development of potential therapeutic strategies.
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Affiliation(s)
- Talieh Malekshahabi
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Niloofar Khoshdel Rad
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Andreas L Serra
- Department of Internal Medicine and Nephrology, Klinik Hirslanden, Zurich, Switzerland
| | - Reza Moghadasali
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
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11
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de Castro-Suárez N, Rodríguez-Vera L, Villegas C, Dávalos-Iglesias JM, Bacallao-Mendez R, Llerena-Ferrer B, Leyva-de la Torre C, Lorenzo-Luaces P, Troche-Concepción M, Ramos-Suzarte M. Pharmacokinetic Evaluation of Nimotuzumab in Patients With Autosomal Dominant Polycystic Kidney Disease. J Clin Pharmacol 2019; 59:863-871. [PMID: 30633365 DOI: 10.1002/jcph.1376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 12/19/2018] [Indexed: 01/05/2023]
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disease characterized by an overexpression and mislocalization of epidermal growth factor receptor (EGFR) to the apical membranes of cystic epithelial cells. Nimotuzumab is a humanized antibody that recognizes an extracellular domain III of human EGFR. The aim of this study was to assess the pharmacokinetic behavior of nimotuzumab in patients with ADPKD given as a single dose. A phase I, single-center, and noncontrolled open clinical study was conducted. Five patients were enrolled at each of the following fixed-dose levels: 50, 100, 200, and 400 mg. Intravenous continuous infusions of nimotuzumab were administered every 14 days during a year, except the first administration, when blood samples were drawn during 28 days for pharmacokinetic assessments. Subjects were closely monitored during the trial and at completion of the administration of nimotuzumab, including the anti-idiotypic response. For the first time, nimotuzumab was used for treating a nononcological disease. The administration of nimotuzumab showed dose-dependent kinetics. Nimotuzumab does not develop anti-idiotypic response against the murine portion present in the hypervariable region of the antibody present in the serum of the patients treated. No significant differences were found in the systemic clearance between the 100- and 400-mg dose, which indicates that the optimal biological dose is in this range of dose.
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Affiliation(s)
- Niurys de Castro-Suárez
- Laboratory of Biopharmaceutics, Department of Pharmacology & Toxicology, Institute of Pharmacy & Foods, University of Havana, Havana, Cuba
| | - Leyanis Rodríguez-Vera
- Laboratory of Biopharmaceutics, Department of Pharmacology & Toxicology, Institute of Pharmacy & Foods, University of Havana, Havana, Cuba
| | - Carlos Villegas
- National Institute of Oncology and Radiobiology, Havana, Cuba
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12
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Jo WR, Kim SH, Kim KW, Suh CH, Kim JK, Kim H, Lee JG, Oh WY, Choi SE, Pyo J. Correlations between renal function and the total kidney volume measured on imaging for autosomal dominant polycystic kidney disease: A systematic review and meta-analysis. Eur J Radiol 2017; 95:56-65. [PMID: 28987699 DOI: 10.1016/j.ejrad.2017.07.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/07/2017] [Accepted: 07/26/2017] [Indexed: 10/19/2022]
Abstract
PURPOSE To provide a systematic summary of total kidney volume (TKV) as an imaging biomarker in clinical trials for autosomal dominant polycystic kidney disease (ADPKD), focusing on the correlation between TKV and renal function. METHODS A computerized literature search was performed using MEDLINE and EMBASE databases for studies that evaluated the correlation between TKV and the glomerular filtration rate (GFR) and between the TKV growth rate and GFR decline rate. A meta-analysis was performed to generate the summary correlation coefficient (r). A qualitative review was performed to evaluate the characteristics of TKV as an imaging biomarker. RESULTS Eighteen articles including a total sample size of 2835 patients were retrieved. Meta-analysis revealed substantial correlations between TKV and GFR [r, -0.520; 95% confidence interval (CI), -0.60 to -0.43] and between the TKV growth rate and GFR decline rate [r, -0.320; 95% CI, -0.54 to -0.10]. The quantitative review revealed that baseline TKV can affect the TKV growth rate and GFR decline rate, such that patients with a higher baseline TKV showed faster TKV growth and GFR decline. There was significant variability in image acquisition and analysis methods. CONCLUSION There were significant negative correlations between TKV and GFR as well as between TKV growth and GFR decline rates, suggesting that TKV imaging is a useful biomarker in clinical trials. However, standardization-or at least trial-specific standardization-of image acquisition and analysis techniques is required to use TKV as a reliable biomarker.
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Affiliation(s)
- Woo Ri Jo
- Department of Radiology, Asan Image Metrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Seong Hee Kim
- Clinical Research Division, National Institute of Food and Drug Safety Evaluation, MFDS, Cheong Ju, Republic of Korea
| | - Kyung Won Kim
- Department of Radiology, Asan Image Metrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
| | - Chong Hyun Suh
- Department of Radiology, Asan Image Metrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jeong Kon Kim
- Department of Radiology, Asan Image Metrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Hyosang Kim
- Department of Nephrology, Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jong Gu Lee
- Clinical Research Division, National Institute of Food and Drug Safety Evaluation, MFDS, Cheong Ju, Republic of Korea
| | - Woo Yong Oh
- Clinical Research Division, National Institute of Food and Drug Safety Evaluation, MFDS, Cheong Ju, Republic of Korea
| | - Seong Eun Choi
- Clinical Research Division, National Institute of Food and Drug Safety Evaluation, MFDS, Cheong Ju, Republic of Korea
| | - Junhee Pyo
- WHO Collaborating Center for Pharmaceutical Policy and Regulation, Department of Pharmaceutical Science, Utrecht University, Netherlands
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13
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Abstract
Many common renal insults such as ischemia and toxic injury primarily target the tubular epithelial cells, especially the highly metabolically active proximal tubular segment. Tubular epithelial cells are particularly dependent on autophagy to maintain homeostasis and respond to stressors. The pattern of autophagy in the kidney has a unique spatial and chronologic signature. Recent evidence has shown that there is complex cross-talk between autophagy and various cell death pathways. This review specifically discusses the interplay between autophagy and cell death in the renal tubular epithelia. It is imperative to review this topic because recent discoveries have improved our mechanistic understanding of the autophagic process and have highlighted its broad clinical applications, making autophagy a major target for drug development.
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Affiliation(s)
- Andrea Havasi
- Department of Nephrology, Boston University Medical Center, Boston, MA.
| | - Zheng Dong
- Department of Nephrology, Second Xiangya Hospital of Central South University, Changsha, China; Department of Cellular Biology and Anatomy, Medical College of Georgia and Charlie Norwood VA Medical Center, Augusta, GA
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Saigusa T, Dang Y, Bunni MA, Amria MY, Steele SL, Fitzgibbon WR, Bell PD. Activation of the intrarenal renin-angiotensin-system in murine polycystic kidney disease. Physiol Rep 2015; 3:3/5/e12405. [PMID: 25999403 PMCID: PMC4463833 DOI: 10.14814/phy2.12405] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The mechanism for early hypertension in polycystic kidney disease (PKD) has not been elucidated. One potential pathway that may contribute to the elevation in blood pressure in PKD is the activation of the intrarenal renin-angiotensin-system (RAS). For example, it has been shown that kidney cyst and cystic fluid contains renin, angiotensin II (AngII), and angiotensinogen (Agt). Numerous studies suggest that ciliary dysfunction plays an important role in PKD pathogenesis. However, it is unknown whether the primary cilium affects the intrarenal RAS in PKD. The purpose of this study was to determine whether loss of cilia or polycystin 1 (PC1) increases intrarenal RAS in mouse model of PKD. Adult Ift88 and Pkd1 conditional floxed allele mice with or without cre were administered tamoxifen to induce global knockout of the gene. Three months after tamoxifen injection, kidney tissues were examined by histology, immunofluorescence, western blot, and mRNA to assess intrarenal RAS components. SV40 immortalized collecting duct cell lines from hypomorphic Ift88 mouse were used to assess intrarenal RAS components in collecting duct cells. Mice without cilia and PC1 demonstrated increased kidney cyst formation, systolic blood pressure, prorenin, and kidney and urinary angiotensinogen levels. Interestingly immunofluorescence study of the kidney revealed that the prorenin receptor was localized to the basolateral membrane of principal cells in cilia (−) but not in cilia (+) kidneys. Collecting duct cAMP responses to AngII administration was greater in cilia (−) vs. cilia (+) cells indicating enhanced intrarenal RAS activity in the absence of cilia. These data suggest that in the absence of cilia or PC1, there is an upregulation of intrarenal RAS components and activity, which may contribute to elevated blood pressure in PKD.
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Affiliation(s)
- Takamitsu Saigusa
- Division of Nephrology, Department of Medicine, Medical University of South Carolina Charleston SC and Ralph Johnson VA Medical Center, Charleston, South Carolina
| | - Yujing Dang
- Division of Nephrology, Department of Medicine, Medical University of South Carolina Charleston SC and Ralph Johnson VA Medical Center, Charleston, South Carolina
| | - Marlene A Bunni
- Division of Nephrology, Department of Medicine, Medical University of South Carolina Charleston SC and Ralph Johnson VA Medical Center, Charleston, South Carolina
| | - May Y Amria
- Division of Nephrology, Department of Medicine, Medical University of South Carolina Charleston SC and Ralph Johnson VA Medical Center, Charleston, South Carolina
| | - Stacy L Steele
- Division of Nephrology, Department of Medicine, Medical University of South Carolina Charleston SC and Ralph Johnson VA Medical Center, Charleston, South Carolina
| | - Wayne R Fitzgibbon
- Division of Nephrology, Department of Medicine, Medical University of South Carolina Charleston SC and Ralph Johnson VA Medical Center, Charleston, South Carolina
| | - P Darwin Bell
- Division of Nephrology, Department of Medicine, Medical University of South Carolina Charleston SC and Ralph Johnson VA Medical Center, Charleston, South Carolina
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15
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Taub M, Parker R, Mathivanan P, Ariff MAM, Rudra T. Antagonism of the prostaglandin E2 EP1 receptor in MDCK cells increases growth through activation of Akt and the epidermal growth factor receptor. Am J Physiol Renal Physiol 2014; 307:F539-50. [PMID: 25007872 DOI: 10.1152/ajprenal.00510.2013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The actions of prostaglandin E2 (PGE2) in the kidney are mediated by G protein-coupled E-prostanoid (EP) receptors, which affect renal growth and function. This report examines the role of EP receptors in mediating the effects of PGE2 on Madin-Darby canine kidney (MDCK) cell growth. The results indicate that activation of Gs-coupled EP2 and EP4 by PGE2 results in increased growth, while EP1 activation is growth inhibitory. Indeed, two EP1 antagonists (ONO-8711 and SC51089) stimulate, rather than inhibit, MDCK cell growth, an effect that is lost following an EP1 knockdown. Similar observations were made with M1 collecting duct and rabbit kidney proximal tubule cells. ONO-8711 even stimulates growth in the absence of exogenous PGE2, an effect that is prevented by ibuprofen (indicating a dependence upon endogenous PGE2). The involvement of Akt was indicated by the observation that 1) ONO-8711 and SC51089 increase Akt phosphorylation, and 2) MK2206, an Akt inhibitor, prevents the increased growth caused by ONO-8711. The involvement of the EGF receptor (EGFR) was indicated by 1) the increased phosphorylation of the EGFR caused by SC51089 and 2) the loss of the growth-stimulatory effect of ONO-8711 and SC51089 caused by the EGFR kinase inhibitor AG1478. The growth-stimulatory effect of ONO-8711 was lost following an EGFR knockdown, and transduction of MDCK cells with a dominant negative EGFR. These results support the hypothesis that 1) signaling via the EP1 receptor involves Akt as well as the EGFR, and 2), EP1 receptor pharmacology may be employed to prevent the aberrant growth associated with a number of renal diseases.
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Affiliation(s)
- Mary Taub
- Biochemistry Department, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, New York
| | - Robert Parker
- Biochemistry Department, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, New York
| | - Paremala Mathivanan
- Biochemistry Department, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, New York
| | - Muhamad Asnawi Mohd Ariff
- Biochemistry Department, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, New York
| | - Trina Rudra
- Biochemistry Department, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, New York
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16
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Braun WE, Schold JD, Stephany BR, Spirko RA, Herts BR. Low-dose rapamycin (sirolimus) effects in autosomal dominant polycystic kidney disease: an open-label randomized controlled pilot study. Clin J Am Soc Nephrol 2014; 9:881-8. [PMID: 24721888 PMCID: PMC4011437 DOI: 10.2215/cjn.02650313] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 01/04/2014] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND OBJECTIVES The two largest studies of mammalian target of rapamycin inhibitor treatment of autosomal dominant polycystic kidney disease (ADPKD) demonstrated no clear benefit on the primary endpoint of total kidney volume (TKV) or on eGFR. The present study evaluated two levels of rapamycin on the 12-month change in (125)I-iothalamate GFR (iGFR) as the primary endpoint and TKV secondarily. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In a 12-month open-label pilot study, 30 adult patients with ADPKD were randomly assigned to low-dose (LD) rapamycin (rapamycin trough blood level, 2-5 ng/ml) (LD group, n=10), standard-dose (STD) rapamycin trough level (>5-8 ng/ml) (STD group, n=10), or standard care (SC group, n=10). They were evaluated with iGFR and noncontrast computed tomography. RESULTS Change in iGFR at 12 months was significantly higher in the LD group (7.7±12.5 ml/min per 1.73 m(2); n=9) than in the SC group (-11.2 ± 9.1 ml/min per 1.73 m(2); n=9) (LD versus SC: P<0.01). Change in iGFR at 12 months in the STD group (1.6 ± 12.1 ml/min per 1.73 m(2); n=8) was not significantly greater than that in the SC group (P=0.07), but it was in the combined treatment groups (LD+STD versus SC: P<0.01). Neither eGFR calculated by the CKD-Epidemiology Collaboration equation nor TKV (secondary endpoint) changed significantly from baseline to 12 months in any of the groups. On the basis of results of the mixed model, during the study, patients in the LD group had significantly lower trough blood levels of rapamycin (mean range ± SD, 2.40 ± 0.64 to 2.90 ± 1.20 ng/ml) compared with those in the STD group (3.93 ± 2.27 to 5.77 ± 1.06 ng/ml) (P<0.01). CONCLUSION Patients with ADPKD receiving LD rapamycin demonstrated a significant increase in iGFR compared with those receiving standard care, without a significant effect on TKV after 12 months.
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Affiliation(s)
- William E Braun
- Glickman Urological and Kidney Institute,, †Quantitative Health Sciences, and, ‡Imaging Institute, Cleveland Clinic, Cleveland, Ohio
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17
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Verkman AS, Synder D, Tradtrantip L, Thiagarajah JR, Anderson MO. CFTR inhibitors. Curr Pharm Des 2013; 19:3529-41. [PMID: 23331030 DOI: 10.2174/13816128113199990321] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 01/16/2013] [Indexed: 12/16/2022]
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) protein is a cAMP-regulated Cl- channel whose major function is to facilitate epithelial fluid secretion. Loss-of-function mutations in CFTR cause the genetic disease cystic fibrosis. CFTR is required for transepithelial fluid transport in certain secretory diarrheas, such as cholera, and for cyst expansion in autosomal dominant polycystic kidney disease. High-throughput screening has yielded CFTR inhibitors of the thiazolidinone, glycine hydrazide and quinoxalinedione chemical classes. The glycine hydrazides target the extracellular CFTR pore, whereas the thiazolidinones and quinoxalinediones act at the cytoplasmic surface. These inhibitors have been widely used in cystic fibrosis research to study CFTR function at the cell and organ levels. The most potent CFTR inhibitor has IC50 of approximately 4 nM. Studies in animal models support the development of CFTR inhibitors for antisecretory therapy of enterotoxin-mediated diarrheas and polycystic kidney disease.
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Affiliation(s)
- Alan S Verkman
- University of California-San Francisco, CA 94143-0521, U.S.A.
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18
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Boehn SNE, Spahn S, Neudecker S, Keppler A, Bihoreau MT, Kränzlin B, Pandey P, Hoffmann SC, Li L, Torres VE, Gröne HJ, Gretz N. Inhibition of Comt with tolcapone slows progression of polycystic kidney disease in the more severely affected PKD/Mhm (cy/+) substrain of the Hannover Sprague-Dawley rat. Nephrol Dial Transplant 2013; 28:2045-58. [PMID: 23543593 DOI: 10.1093/ndt/gft014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common human inherited diseases. Modifier genes seem to modulate the disease progression and might therefore be promising drug targets. Although a number of modifier loci have been already identified, no modifier gene has been proven to be a real modifier yet. METHODS Gene expression profiling of two substrains of the Han:SPRD rat, namely PKD/Mhm and PKD/US, both harboring the same mutation, was conducted in 36-day-old animals. Catechol-O-methyltransferase (Comt) was identified as a potential modifier gene. A 3-month treatment with tolcapone, a selective inhibitor of Comt, was carried out in PKD/Mhm and PKD/US (cy/+) animals. RESULTS Comt is localized within a known modifier locus of PKD (MOP2). The enzyme encoding gene was found upregulated in the more severely affected PKD/Mhm substrain and was hence presumed to be a putative modifier gene of PKD. The treatment with tolcapone markedly attenuated the loss of renal function, inhibited renal enlargement, shifted the size distribution of renal cysts and retarded cell proliferation, apoptosis, inflammation and fibrosis development in affected (cy/+) male and female PKD/Mhm and PKD/US rats. CONCLUSIONS Comt has been confirmed to be the first reported modifier gene for PKD and tolcapone offers a promising drug for treating PKD.
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Affiliation(s)
- Susanne N E Boehn
- Medical Research Center, University of Heidelberg, Mannheim, Germany
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19
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Abstract
Renal cysts are a common radiological finding in both adults and children. They occur in a variety of conditions, and the clinical presentation, management, and prognosis varies widely. In this article, we discuss the major causes of renal cysts in children and adults with a particular focus on the most common genetic forms. Many cystoproteins have been localized to the cilia centrosome complex (CCC). We consider the evidence for a universal 'cilia hypothesis' for cyst formation and the evidence for non-ciliary proteins in cyst formation.
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20
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Bukanov NO, Moreno SE, Natoli TA, Rogers KA, Smith LA, Ledbetter SR, Oumata N, Galons H, Meijer L, Ibraghimov-Beskrovnaya O. CDK inhibitors R-roscovitine and S-CR8 effectively block renal and hepatic cystogenesis in an orthologous model of ADPKD. Cell Cycle 2012; 11:4040-6. [PMID: 23032260 PMCID: PMC3507499 DOI: 10.4161/cc.22375] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) and other forms of PKD are associated with dysregulated cell cycle and proliferation. Although no effective therapy for the treatment of PKD is currently available, possible mechanism-based approaches are beginning to emerge. A therapeutic intervention targeting aberrant cilia-cell cycle connection using CDK-inhibitor R-roscovitine showed effective arrest of PKD in jck and cpk models that are not orthologous to human ADPKD. To evaluate whether CDK inhibition approach will translate into efficacy in an orthologous model of ADPKD, we tested R-roscovitine and its derivative S-CR8 in a model with a conditionally inactivated Pkd1 gene (Pkd1 cKO). Similar to ADPKD, Pkd1 cKO mice developed renal and hepatic cysts. Treatment of Pkd1 cKO mice with R-roscovitine and its more potent and selective analog S-CR8 significantly reduced renal and hepatic cystogenesis and attenuated kidney function decline. Mechanism of action studies demonstrated effective blockade of cell cycle and proliferation and reduction of apoptosis. Together, these data validate CDK inhibition as a novel and effective approach for the treatment of ADPKD.
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21
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Kim HJ, Edelstein CL. Mammalian target of rapamycin inhibition in polycystic kidney disease: From bench to bedside. Kidney Res Clin Pract 2012; 31:132-8. [PMID: 26894018 PMCID: PMC4716095 DOI: 10.1016/j.krcp.2012.07.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 06/19/2012] [Accepted: 06/19/2012] [Indexed: 10/28/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is the most common life-threatening hereditary disease in the USA resulting in chronic kidney disease and the need for dialysis and transplantation. Approximately 85% of cases of ADPKD are caused by a mutation in the Pkd1 gene that encodes polycystin-1, a large membrane receptor. The Pkd1 gene mutation results in abnormal proliferation in tubular epithelial cells, which plays a crucial role in cyst development and/or growth in PKD. Activation of the proliferative mammalian target of rapamycin (mTOR) signaling pathway has been demonstrated in polycystic kidneys from rodents and humans. mTOR inhibition with sirolimus or everolimus decreases cysts in most animal models of PKD including Pkd1 and Pkd2 gene deficient orthologous models of human disease. On the basis of animal studies, human studies were undertaken. Two large randomized clinical trials published in the New England Journal of Medicine of everolimus or sirolimus in ADPKD patients were very unimpressive and associated with a high side-effect profile. Possible reasons for the unimpressive nature of the human studies include their short duration, the high drop-out rate, suboptimal dosing, lack of randomization of "fast" and "slow progressors" and the lack of correlation between kidney size and kidney function in ADPKD. The future of mTOR inhibition in ADPKD is discussed.
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Affiliation(s)
- Hyun-Jung Kim
- Division of Renal Diseases and Hypertension, Univ. of Colorado at Denver, Aurora, Colorado, USA
- Department of Internal Medicine, School of Medicine, Gyeongsang National University, Jinju, Korea
| | - Charles L. Edelstein
- Division of Renal Diseases and Hypertension, Univ. of Colorado at Denver, Aurora, Colorado, USA
- Corresponding author. University of Colorado at Denver and the Health Sciences Center, Box C281, 12700 East, 19th Ave, Aurora, CO 80262, USA.
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WITHDRAWN: Mammalian target of rapamycin (mTOR) inhibition in polycystic kidney disease (PKD): From bench to bedside. Kidney Res Clin Pract 2012. [DOI: 10.1016/j.krcp.2012.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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23
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Huber TB, Edelstein CL, Hartleben B, Inoki K, Jiang M, Koya D, Kume S, Lieberthal W, Pallet N, Quiroga A, Ravichandran K, Susztak K, Yoshida S, Dong Z. Emerging role of autophagy in kidney function, diseases and aging. Autophagy 2012; 8:1009-31. [PMID: 22692002 PMCID: PMC3429540 DOI: 10.4161/auto.19821] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/24/2012] [Accepted: 02/27/2012] [Indexed: 02/06/2023] Open
Abstract
Autophagy is a highly conserved process that degrades cellular long-lived proteins and organelles. Accumulating evidence indicates that autophagy plays a critical role in kidney maintenance, diseases and aging. Ischemic, toxic, immunological, and oxidative insults can cause an induction of autophagy in renal epithelial cells modifying the course of various kidney diseases. This review summarizes recent insights on the role of autophagy in kidney physiology and diseases alluding to possible novel intervention strategies for treating specific kidney disorders by modifying autophagy.
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Affiliation(s)
- Tobias B Huber
- Renal Division, University Hospital Freiburg; Freiburg, Germany.
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Zhou H, Gao J, Zhou L, Li X, Li W, Li X, Xia Y, Yang B. Ginkgolide B inhibits renal cyst development in in vitro and in vivo cyst models. Am J Physiol Renal Physiol 2012; 302:F1234-42. [PMID: 22338085 DOI: 10.1152/ajprenal.00356.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) is a common inherited disease characterized by massive enlargement of fluid-filled cysts in the kidney. However, there is no effective therapy yet for this disease. To examine whether ginkgolide B, a natural compound, inhibits cyst development, a Madin-Darby canine kidney (MDCK) cyst model, an embryonic kidney cyst model, and a PKD mouse model were used. Interestingly, ginkgolide B significantly inhibited MDCK cyst formation dose dependently, with up to 69% reduction by 2 μM ginkgolide B. Ginkgolide B also significantly inhibited cyst enlargement in the MDCK cyst model, embryonic kidney cyst model, and PKD mouse model. To determine the underlying mechanisms, the effect of ginkgolide B on MDCK cell viability, proliferation, apoptosis, chloride transporter CFTR activity, and intracellular signaling pathways were also studied. Ginkgolide B did not affect cell viability, proliferation, and expression and activity of the chloride transporter CFTR that mediates cyst fluid secretion. Ginkgolide B induced cyst cell differentiation and altered the Ras/MAPK signaling pathway. Taken together, our results demonstrate that ginkgolide B inhibits renal cyst formation and enlargement, suggesting that ginkgolide B might be developed into a novel candidate drug for ADPKD.
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Affiliation(s)
- Hong Zhou
- Dept. of Pharmacology. School of Basic Medical Sciences, Peking Univ., 38 Xueyuan Lu, Haidian District, Beijing 100191, China
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25
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Abstract
Polycystic kidney disease (PKD) is a common genetic disorder in which extensive epithelial-lined cysts develop in the kidneys. In previous studies, abnormalities of polycystin protein and its interacting proteins, as well as primary cilia, have been suggested to play critical roles in the development of renal cysts. However, although several therapeutic targets for PKD have been suggested, no early diagnosis or effective treatments are currently available. Current developments are active for treatment of PKD including inhibitors or antagonists of PPAR-γ, TNF-α, CDK and VEGF. These drugs are potential therapeutic targets in PKD, and need to be determined about pathological functions in human PKD. It has recently been reported that the alteration of epigenetic regulation, as well as gene mutations, may affect the pathogenesis of PKD. In this review, we will discuss recent approaches to PKD therapy. It provides important information regarding potential targets for PKD.
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Affiliation(s)
- Eun Young Park
- Department of Biological Science, Sookmyung Women's University, Seoul 140-742, Korea
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26
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Watanabe T. [108th Scientific Meeting of The Japanese Society of Internal Medicine: symposium: 3. The interaction between kidney and other organs; what should physicians know about it? (3) Physiological and pathophysiological interaction between liver and kidney]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2011; 100:2544-2551. [PMID: 22117349 DOI: 10.2169/naika.100.2544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- Tsuyoshi Watanabe
- Department of Nephrology, Hypertension Diabetology, Endocrinology and Metabolic, Fukushima Medical University School of Medicine, Japan
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27
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Snyder DS, Tradtrantip L, Yao C, Kurth MJ, Verkman AS. Potent, metabolically stable benzopyrimido-pyrrolo-oxazine-dione (BPO) CFTR inhibitors for polycystic kidney disease. J Med Chem 2011; 54:5468-77. [PMID: 21707078 DOI: 10.1021/jm200505e] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We previously reported the discovery of pyrimido-pyrrolo-quinoxalinedione (PPQ) inhibitors of the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel and showed their efficacy in an organ culture model of polycystic kidney disease (PKD) (J. Med. Chem. 2009, 52, 6447-6455). Here, we report related benzopyrimido-pyrrolo-oxazinedione (BPO) CFTR inhibitors. To establish structure-activity relationships and select lead compound(s) with improved potency, metabolic stability, and aqueous solubility compared to the most potent prior compound 8 (PPQ-102, IC(50) ∼ 90 nM), we synthesized 16 PPQ analogues and 11 BPO analogues. The analogues were efficiently synthesized in 5-6 steps and 11-61% overall yield. Modification of 8 by bromine substitution at the 5-position of the furan ring, replacement of the secondary amine with an ether bridge, and carboxylation, gave 6-(5-bromofuran-2-yl)-7,9-dimethyl-8,10-dioxo-11-phenyl-7,8,9,10-tetrahydro-6H-benzo[b]pyrimido [4',5':3,4]pyrrolo [1,2-d][1,4]oxazine-2-carboxylic acid 42 (BPO-27), which fully inhibited CFTR with IC(50) ∼ 8 nM and, compared to 8, had >10-fold greater metabolic stability and much greater polarity/aqueous solubility. In an embryonic kidney culture model of PKD, 42 prevented cyst growth with IC(50) ∼ 100 nM. Benzopyrimido-pyrrolo-oxazinediones such as 42 are potential development candidates for antisecretory therapy of PKD.
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Affiliation(s)
- David S Snyder
- Department of Medicine, University of California, San Francisco, California 94143-0521, United States
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Leonhard WN, van der Wal A, Novalic Z, Kunnen SJ, Gansevoort RT, Breuning MH, de Heer E, Peters DJM. Curcumin inhibits cystogenesis by simultaneous interference of multiple signaling pathways: in vivo evidence from aPkd1-deletion model. Am J Physiol Renal Physiol 2011; 300:F1193-202. [DOI: 10.1152/ajprenal.00419.2010] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Autosomal dominant polycystic kidney disease (ADPKD) caused by mutations in either the PKD1 or PKD2 gene is a major cause of end-stage renal failure. A number of compounds targeting specific signaling pathways were able to inhibit cystogenesis in rodent models and are currently being tested in clinical trials. However, given the complex signaling in ADPKD, an ideal therapy would likely have to comprise several pathways at once. Therefore, multitarget compounds may provide promising therapeutic interventions for the treatment of ADPKD. To test this hypothesis, we treated Pkd1-deletion mice with diferuloylmethane (curcumin), a compound without appreciable side effects and known to modulate several pathways that are also altered in ADPKD, e.g., mammalian target of rapamycin (mTOR) and Wnt signaling. After conditional inactivation of Pkd1, mTOR signaling was indeed elevated in cystic kidneys. Interestingly, also activation of signal transducers and activator of transcription 3 (STAT3) strongly correlated with cyst progression. Both pathways were effectively inhibited in vitro by curcumin. Importantly, Pkd1-deletion mice that were treated with curcumin and killed at an early stage of PKD displayed improved renal histology and reduced STAT3 activation, proliferation index, cystic index, and kidney weight/body weight ratios. In addition, renal failure was significantly postponed in mice with severe PKD. These data suggest that multitarget compounds hold promising potential for safe and effective treatment of ADPKD.
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Affiliation(s)
| | | | | | | | - Ron T. Gansevoort
- Division of Nephrology, Department of Internal Medicine, University Medical Center Groningen, Groningen, The Netherlands
| | | | - Emile de Heer
- Pathology, Leiden University Medical Center, Leiden; and
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Belibi F, Zafar I, Ravichandran K, Segvic AB, Jani A, Ljubanovic DG, Edelstein CL. Hypoxia-inducible factor-1α (HIF-1α) and autophagy in polycystic kidney disease (PKD). Am J Physiol Renal Physiol 2011; 300:F1235-43. [PMID: 21270095 PMCID: PMC3094047 DOI: 10.1152/ajprenal.00348.2010] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 01/24/2011] [Indexed: 01/05/2023] Open
Abstract
Cyst expansion in polycystic kidney disease (PKD) results in localized hypoxia in the kidney that may activate hypoxia-inducible factor-1α (HIF-1α). HIF-1α and autophagy, a form of programmed cell repair, are induced by hypoxia. The purposes were to determine HIF-1α expression and autophagy in rat and mouse models of PKD. HIF-1α was detected by electrochemiluminescence. Autophagy was visualized by electron microscopy (EM). LC3 and beclin-1, markers of autophagy, were detected by immunoblotting. Eight-week-old male heterozygous (Cy/+) and 4-wk-old homozygous (Cy/Cy) Han:SPRD rats, 4-wk-old cpk mice, and 112-day-old Pkd2WS25/- mice with a mutation in the Pkd2 gene were studied. HIF-1α was significantly increased in massive Cy/Cy and cpk kidneys and not smaller Cy/+ and Pkd2WS25/- kidneys. On EM, features of autophagy were seen in wild-type (+/+), Cy/+, and cpk kidneys: autophagosomes, mitophagy, and autolysosomes. Specifically, autophagosomes were found on EM in the tubular cells lining the cysts in cpk mice. The increase in LC3-II, a marker of autophagosome production and beclin, a regulator of autophagy, in Cy/Cy and cpk kidneys, followed the same pattern of increase as HIF-1α. To determine the role of HIF-1α in cyst formation and/or growth, Cy/+ rats, Cy/Cy rats, and cpk mice were treated with the HIF-1α inhibitor 2-methoxyestradiol (2ME2). 2ME2 had no significant effect on kidney volume or cyst volume density. In summary, HIF-1α is highly expressed in the late stages of PKD and is associated with an increase in LC3-II and beclin-1. The first demonstration of autophagosomes in PKD kidneys is reported. Inhibition of HIF-1α did not have a therapeutic effect.
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Affiliation(s)
- Franck Belibi
- Division of Renal Diseases and Hypertension, University of Colorado at Denver and Health Sciences Center, Aurora, 80262, USA
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Pharmacological characterization of adenylyl cyclase isoforms in rabbit kidney membranes. Naunyn Schmiedebergs Arch Pharmacol 2011; 383:357-72. [PMID: 21279330 DOI: 10.1007/s00210-011-0600-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 01/07/2011] [Indexed: 10/18/2022]
Abstract
Polycystic kidney disease (PKD) is the most common life-threatening genetic disorder with bilateral cysts caused by increased level of cyclic adenosine 3',5'-monophosphate (cAMP). Since adenylyl cyclases (ACs) catalyze cAMP formation, pharmacological characterization of renal AC isoforms is essential. Therefore, we analyzed differences in activation, inhibition, and regulation of AC isoforms in rabbit cortex and medulla membranes. Glucagon, [8-arginine]vasopressin (AVP) and catecholamines significantly activated cortical AC. However, in medulla only glucagon and AVP activated AC. Under Mg(2+) conditions the profile of cortical membrane AC enzyme kinetics and the inhibitory profile of 2'(3')-O-(N-methylanthraniloyl) (MANT) nucleotides resembled recombinant AC5. In contrast, the K (i) values of MANT nucleotides for medullary membrane AC and its kinetic properties were similar to those of recombinant AC1. Reverse-transcriptase PCR confirmed the presence of AC1 and AC5 in medulla and cortex, respectively. Cortical AC was sensitive to inhibition by Ca(2+), corroborating the importance of AC5. However, Ca(2+)/CaM dependency specific for AC1 was not found in medulla. In conclusion, according to expression, kinetics and inhibition by MANT nucleotides both parts of the kidney differ in their AC isoforms. Whereas Ca(2+)-inhibitable AC5 was confirmed in renal cortex, the initially assumed AC1 activation in medulla could not be confirmed, pointing to the involvement of another AC isoform with some similarity to AC1. Since PKD is characterized by predominant involvement of the collecting duct and the distal nephrons located in renal cortex, AC5 may be the major AC isoform in this part of the kidney where cAMP increases cyst growth. Thus, potent and selective AC5 inhibitors could constitute a novel approach to treat PKD.
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Virzì GM, Corradi V, Panagiotou A, Gastaldon F, Cruz DN, de Cal M, Clementi M, Ronco C. ADPKD: Prototype of Cardiorenal Syndrome Type 4. Int J Nephrol 2010; 2011:490795. [PMID: 21234092 PMCID: PMC3017903 DOI: 10.4061/2011/490795] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 10/26/2010] [Indexed: 11/20/2022] Open
Abstract
The cardiorenal syndrome type 4 (Chronic Renocardiac Syndrome) is characterized by a condition of primary chronic kidney disease (CKD) that leads to an impairment of the cardiac function, ventricular hypertrophy, diastolic dysfunction, and/or increased risk of adverse cardiovascular events. Clinically, it is very difficult to distinguish between CRS type 2 (Chronic Cardiorenal Syndrome) and CRS type 4 (Chronic Renocardiac Syndrome) because often it is not clear whether the primary cause of the syndrome depends on the heart or the kidney. Autosomal dominant polycystic kidney disease (ADPKD), a genetic disease that causes CKD, could be viewed as an ideal prototype of CRS type 4 because it is certain that the primary cause of cardiorenal syndrome is the kidney disease. In this paper, we will briefly review the epidemiology of ADPKD, conventional and novel biomarkers which may be useful in following the disease process, and prevention and treatment strategies.
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Affiliation(s)
- Grazia Maria Virzì
- Department of Nephrology, Dialysis and Transplantation, St. Bortolo Hospital, Via Rodolfi 37, 36100 Vicenza, Italy
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Pedersen EB, Thomsen IM, Lauridsen TG. Abnormal function of the vasopressin-cyclic-AMP-aquaporin2 axis during urine concentrating and diluting in patients with reduced renal function. A case control study. BMC Nephrol 2010; 11:26. [PMID: 20923561 PMCID: PMC2965705 DOI: 10.1186/1471-2369-11-26] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 10/05/2010] [Indexed: 12/22/2022] Open
Abstract
Background The kidneys ability to concentrate and dilute urine is deteriorated during progressive renal insufficiency. We wanted to test the hypothesis that these phenomena could be attributed to an abnormal function of the principal cells in the distal part of the nephron. Methods Healthy control subjects and patients with chronic kidney diseases were studied. Group 1 comprised healthy subjects, n = 10. Groups 2-4 comprised patients with chronic kidney disease (Group 2, n = 14, e-GFR ? 90 m1/min; Group 3, n = 11, 60 m1/min ? e-GFR < 90 ml/min; and Group 4, n = 16, 15 ml/min ? e-GFR < 60 ml/min). The subjects collected urine during 24 hours. A urine concentrating test was done by thirsting during the following 12 hours. Thereafter, a urine diluting test was performed with a water load of 20 ml/kg body weight. The effect variables were urinary excretions of aquaporin2 (u-AQP2), cyclic-AMP (u-c-AMP), urine volume (UV), free water clearance (CH2O), urine osmolarity (u-Osm), and plasma arginine vasopressin (p-AVP). Results After fluid deprivation, u-Osm increased. In all groups, UV and CH2O decreased and u-AQP2 and u-c-AMP increased in Groups 1 and 2, but were unchanged in Group 3 and 4. P-AVP was significantly higher in Group 4 than in the other groups. During urine diluting, UV and CH2O reached significantly higher levels in Groups 1-3 than Group 4. Both before and after water loading, u-AQP2 and p-AVP were significantly higher and u-c-AMP was significantly lower in Group 4 than the other groups. Estimated-GFR was correlated negatively to p-AVP and positively to u-c-AMP. Conclusions Patients with moderately severe chronic kidney disease have a reduced renal concentrating and diluting capacity compared to both patients with milder chronic kidney disease and healthy control subjects. These phenomena can be attributed, at least partly, to an abnormally decreased response in the AVP-c-AMP-AQP2 axis. ClinicalTrials.Gov Identifier: NCT00313430
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Affiliation(s)
- Erling B Pedersen
- Department of Medical Research, Holstebro Hospital, Laegaardvej 12, 7500 Holstebro, Denmark.
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Abstract
Hyponatremia is a common problem in patients with advanced cirrhosis. Hyponatremia in cirrhosis includes two distinct types: hypovolemic hyponatremia, and hypervolemic or dilutional hyponatremia. The former is characterized by low blood sodium, low blood volume, dehydration and prerenal renal dysfunction, not accompanied by edema and ascites, while the latter is characterized by insufficient circulatory volume and dilutional hyponatremia, accompanied by edema and ascites. Hyponatremia is closely related to various complications of cirrhosis and to early mortality after liver transplantation. Vaptans, a class of selective non-peptide arginine vasopressin (AVP) receptor antagonists, act by antagonizing specifically the effects of AVP V2 receptor located in the renal collecting tubules to inhibit water reabsorption without affecting electrolytes excretion. Vaptans has been evaluated by several clinical trials for their role in the management of hyponatremia. The short-term treatment with vaptans is associated with a marked increase in renal solute-free water excretion and improvement of hyponatremia with no apparent adverse reactions. The discovery of vaptans is considered a new milestone in the management of hyponatremia in cirrhosis.
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