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Cheung PY, Harrison PT, Davidson AJ, Hollywood JA. In Vitro and In Vivo Models to Study Nephropathic Cystinosis. Cells 2021; 11:6. [PMID: 35011573 PMCID: PMC8750259 DOI: 10.3390/cells11010006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 12/17/2021] [Accepted: 12/19/2021] [Indexed: 12/18/2022] Open
Abstract
The development over the past 50 years of a variety of cell lines and animal models has provided valuable tools to understand the pathophysiology of nephropathic cystinosis. Primary cultures from patient biopsies have been instrumental in determining the primary cause of cystine accumulation in the lysosomes. Immortalised cell lines have been established using different gene constructs and have revealed a wealth of knowledge concerning the molecular mechanisms that underlie cystinosis. More recently, the generation of induced pluripotent stem cells, kidney organoids and tubuloids have helped bridge the gap between in vitro and in vivo model systems. The development of genetically modified mice and rats have made it possible to explore the cystinotic phenotype in an in vivo setting. All of these models have helped shape our understanding of cystinosis and have led to the conclusion that cystine accumulation is not the only pathology that needs targeting in this multisystemic disease. This review provides an overview of the in vitro and in vivo models available to study cystinosis, how well they recapitulate the disease phenotype, and their limitations.
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Affiliation(s)
- Pang Yuk Cheung
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland 1142, New Zealand; (P.Y.C.); (A.J.D.)
| | - Patrick T. Harrison
- Department of Physiology, BioSciences Institute, University College Cork, T12 XF62 Cork, Ireland;
| | - Alan J. Davidson
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland 1142, New Zealand; (P.Y.C.); (A.J.D.)
| | - Jennifer A. Hollywood
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland 1142, New Zealand; (P.Y.C.); (A.J.D.)
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2
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Jamalpoor A, van Gelder CAGH, Yousef Yengej FA, Zaal EA, Berlingerio SP, Veys KR, Pou Casellas C, Voskuil K, Essa K, Ammerlaan CME, Rega LR, van der Welle REN, Lilien MR, Rookmaaker MB, Clevers H, Klumperman J, Levtchenko E, Berkers CR, Verhaar MC, Altelaar M, Masereeuw R, Janssen MJ. Cysteamine-bicalutamide combination therapy corrects proximal tubule phenotype in cystinosis. EMBO Mol Med 2021; 13:e13067. [PMID: 34165243 PMCID: PMC8261496 DOI: 10.15252/emmm.202013067] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 05/20/2021] [Accepted: 05/21/2021] [Indexed: 11/20/2022] Open
Abstract
Nephropathic cystinosis is a severe monogenic kidney disorder caused by mutations in CTNS, encoding the lysosomal transporter cystinosin, resulting in lysosomal cystine accumulation. The sole treatment, cysteamine, slows down the disease progression, but does not correct the established renal proximal tubulopathy. Here, we developed a new therapeutic strategy by applying omics to expand our knowledge on the complexity of the disease and prioritize drug targets in cystinosis. We identified alpha-ketoglutarate as a potential metabolite to bridge cystinosin loss to autophagy, apoptosis and kidney proximal tubule impairment in cystinosis. This insight combined with a drug screen revealed a bicalutamide-cysteamine combination treatment as a novel dual-target pharmacological approach for the phenotypical correction of cystinotic kidney proximal tubule cells, patient-derived kidney tubuloids and cystinotic zebrafish.
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Affiliation(s)
- Amer Jamalpoor
- Division of PharmacologyDepartment of Pharmaceutical SciencesFaculty of ScienceUtrecht UniversityUtrechtThe Netherlands
| | - Charlotte AGH van Gelder
- Biomolecular Mass Spectrometry and ProteomicsBijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical SciencesUtrecht UniversityUtrechtThe Netherlands
- Netherlands Proteomics CenterUtrechtThe Netherlands
| | - Fjodor A Yousef Yengej
- Hubrecht Institute‐Royal Netherlands Academy of Arts and Sciences and University Medical Center UtrechtUtrechtThe Netherlands
- Department of Nephrology and HypertensionUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Esther A Zaal
- Biomolecular Mass Spectrometry and ProteomicsBijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical SciencesUtrecht UniversityUtrechtThe Netherlands
- Division of Cell Biology, Cancer & MetabolismDepartment of Biomolecular Health SciencesFaculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Sante P Berlingerio
- Department of Pediatric Nephrology & Growth and RegenerationUniversity Hospitals Leuven & KU LeuvenLeuvenBelgium
| | - Koenraad R Veys
- Department of Pediatric Nephrology & Growth and RegenerationUniversity Hospitals Leuven & KU LeuvenLeuvenBelgium
| | - Carla Pou Casellas
- Division of PharmacologyDepartment of Pharmaceutical SciencesFaculty of ScienceUtrecht UniversityUtrechtThe Netherlands
| | - Koen Voskuil
- Division of PharmacologyDepartment of Pharmaceutical SciencesFaculty of ScienceUtrecht UniversityUtrechtThe Netherlands
| | - Khaled Essa
- Division of PharmacologyDepartment of Pharmaceutical SciencesFaculty of ScienceUtrecht UniversityUtrechtThe Netherlands
| | - Carola ME Ammerlaan
- Hubrecht Institute‐Royal Netherlands Academy of Arts and Sciences and University Medical Center UtrechtUtrechtThe Netherlands
- Department of Nephrology and HypertensionUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Laura Rita Rega
- Renal Diseases Research Unit, Genetics and Rare Diseases Research AreaBambino Gesù Children’s HospitalIRCCSRomeItaly
| | - Reini EN van der Welle
- Section Cell BiologyCenter for Molecular MedicineUniversity Medical Center UtrechtUtrecht UniversityUtrechtThe Netherlands
| | - Marc R Lilien
- Department of Pediatric NephrologyWilhelmina Children’s HospitalUniversity Medical Centre UtrechtUtrechtThe Netherlands
| | - Maarten B Rookmaaker
- Department of Nephrology and HypertensionUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Hans Clevers
- Hubrecht Institute‐Royal Netherlands Academy of Arts and Sciences and University Medical Center UtrechtUtrechtThe Netherlands
| | - Judith Klumperman
- Section Cell BiologyCenter for Molecular MedicineUniversity Medical Center UtrechtUtrecht UniversityUtrechtThe Netherlands
| | - Elena Levtchenko
- Department of Pediatric Nephrology & Growth and RegenerationUniversity Hospitals Leuven & KU LeuvenLeuvenBelgium
| | - Celia R Berkers
- Biomolecular Mass Spectrometry and ProteomicsBijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical SciencesUtrecht UniversityUtrechtThe Netherlands
- Division of Cell Biology, Cancer & MetabolismDepartment of Biomolecular Health SciencesFaculty of Veterinary MedicineUtrecht UniversityUtrechtThe Netherlands
| | - Marianne C Verhaar
- Department of Nephrology and HypertensionUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and ProteomicsBijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical SciencesUtrecht UniversityUtrechtThe Netherlands
- Netherlands Proteomics CenterUtrechtThe Netherlands
| | - Rosalinde Masereeuw
- Division of PharmacologyDepartment of Pharmaceutical SciencesFaculty of ScienceUtrecht UniversityUtrechtThe Netherlands
| | - Manoe J Janssen
- Division of PharmacologyDepartment of Pharmaceutical SciencesFaculty of ScienceUtrecht UniversityUtrechtThe Netherlands
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3
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Bondue T, Arcolino FO, Veys KRP, Adebayo OC, Levtchenko E, van den Heuvel LP, Elmonem MA. Urine-Derived Epithelial Cells as Models for Genetic Kidney Diseases. Cells 2021; 10:cells10061413. [PMID: 34204173 PMCID: PMC8230018 DOI: 10.3390/cells10061413] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/28/2021] [Accepted: 06/02/2021] [Indexed: 12/11/2022] Open
Abstract
Epithelial cells exfoliated in human urine can include cells anywhere from the urinary tract and kidneys; however, podocytes and proximal tubular epithelial cells (PTECs) are by far the most relevant cell types for the study of genetic kidney diseases. When maintained in vitro, they have been proven extremely valuable for discovering disease mechanisms and for the development of new therapies. Furthermore, cultured patient cells can individually represent their human sources and their specific variants for personalized medicine studies, which are recently gaining much interest. In this review, we summarize the methodology for establishing human podocyte and PTEC cell lines from urine and highlight their importance as kidney disease cell models. We explore the well-established and recent techniques of cell isolation, quantification, immortalization and characterization, and we describe their current and future applications.
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Affiliation(s)
- Tjessa Bondue
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
| | - Fanny O. Arcolino
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
| | - Koenraad R. P. Veys
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
- Department of Pediatrics, Division of Pediatric Nephrology, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Oyindamola C. Adebayo
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
- Centre for Molecular and Vascular Biology, Department of Cardiovascular Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Elena Levtchenko
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
- Department of Pediatrics, Division of Pediatric Nephrology, University Hospitals Leuven, 3000 Leuven, Belgium
| | - Lambertus P. van den Heuvel
- Department of Development and Regeneration, KU Leuven, 3000 Leuven, Belgium; (T.B.); (F.O.A.); (K.R.P.V.); (O.C.A.); (E.L.); (L.P.v.d.H.)
- Department of Pediatric Nephrology, Radboud University Medical Center, 6500 Nijmegen, The Netherlands
| | - Mohamed A. Elmonem
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo 11628, Egypt
- Correspondence:
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4
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Jamalpoor A, Othman A, Levtchenko EN, Masereeuw R, Janssen MJ. Molecular Mechanisms and Treatment Options of Nephropathic Cystinosis. Trends Mol Med 2021; 27:673-686. [PMID: 33975805 DOI: 10.1016/j.molmed.2021.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/15/2022]
Abstract
Nephropathic cystinosis is a severe, monogenic systemic disorder that presents early in life and leads to progressive organ damage, particularly affecting the kidneys. It is caused by mutations in the CTNS gene, which encodes the lysosomal transporter cystinosin, resulting in intralysosomal accumulation of cystine. Recent studies demonstrated that the loss of cystinosin is associated with disrupted autophagy dynamics, accumulation of distorted mitochondria, and increased oxidative stress, leading to abnormal proliferation and dysfunction of kidney cells. We discuss these molecular mechanisms driving nephropathic cystinosis. Further, we consider how unravelling molecular mechanisms supports the identification and development of new strategies for cystinosis by the use of small molecules, biologicals, and genetic rescue of the disease in vitro and in vivo.
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Affiliation(s)
- Amer Jamalpoor
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584, CG, Utrecht, The Netherlands
| | - Amr Othman
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584, CG, Utrecht, The Netherlands
| | - Elena N Levtchenko
- Department of Pediatric Nephrology & Growth and Regeneration, University Hospitals Leuven & KU Leuven, Leuven, Belgium
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584, CG, Utrecht, The Netherlands.
| | - Manoe J Janssen
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, 3584, CG, Utrecht, The Netherlands.
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Festa BP, Berquez M, Nieri D, Luciani A. Endolysosomal Disorders Affecting the Proximal Tubule of the Kidney: New Mechanistic Insights and Therapeutics. Rev Physiol Biochem Pharmacol 2021; 185:233-257. [PMID: 33649992 DOI: 10.1007/112_2020_57] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Epithelial cells that line the proximal tubule of the kidney rely on an intertwined ecosystem of vesicular membrane trafficking pathways to ensure the reabsorption of essential nutrients. To function effectively and to achieve homeostasis, these specialized cells require the sorting and recycling of a wide array of cell surface proteins within the endolysosomal network, including signaling receptors, nutrient transporters, ion channels, and polarity markers. The dysregulation of the endolysosomal system can lead to a generalized proximal tubule dysfunction, ultimately causing severe metabolic complications and kidney disease.In this chapter, we highlight the biological functions of the genes that code endolysosomal proteins from the perspective of understanding - and potentially reversing - the pathophysiology of endolysosomal disorders affecting the proximal tubule of the kidney. These insights might ultimately lead to potential treatments for currently intractable diseases and transform our ability to regulate kidney homeostasis and health.
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Affiliation(s)
- Beatrice Paola Festa
- Institute of Physiology, Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland
| | - Marine Berquez
- Institute of Physiology, Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland
| | - Daniela Nieri
- Institute of Physiology, Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland
| | - Alessandro Luciani
- Institute of Physiology, Mechanisms of Inherited Kidney Disorders Group, University of Zurich, Zurich, Switzerland.
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6
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De Leo E, Elmonem MA, Berlingerio SP, Berquez M, Festa BP, Raso R, Bellomo F, Starborg T, Janssen MJ, Abbaszadeh Z, Cairoli S, Goffredo BM, Masereeuw R, Devuyst O, Lowe M, Levtchenko E, Luciani A, Emma F, Rega LR. Cell-Based Phenotypic Drug Screening Identifies Luteolin as Candidate Therapeutic for Nephropathic Cystinosis. J Am Soc Nephrol 2020; 31:1522-1537. [PMID: 32503896 DOI: 10.1681/asn.2019090956] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 04/04/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Mutations in the gene that encodes the lysosomal cystine transporter cystinosin cause the lysosomal storage disease cystinosis. Defective cystine transport leads to intralysosomal accumulation and crystallization of cystine. The most severe phenotype, nephropathic cystinosis, manifests during the first months of life, as renal Fanconi syndrome. The cystine-depleting agent cysteamine significantly delays symptoms, but it cannot prevent progression to ESKD and does not treat Fanconi syndrome. This suggests the involvement of pathways in nephropathic cystinosis that are unrelated to lysosomal cystine accumulation. Recent data indicate that one such potential pathway, lysosome-mediated degradation of autophagy cargoes, is compromised in cystinosis. METHODS To identify drugs that reduce levels of the autophagy-related protein p62/SQSTM1 in cystinotic proximal tubular epithelial cells, we performed a high-throughput screening on the basis of an in-cell ELISA assay. We then tested a promising candidate in cells derived from patients with, and mouse models of, cystinosis, and in preclinical studies in cystinotic zebrafish. RESULTS Of 46 compounds identified as reducing p62/SQSTM1 levels in cystinotic cells, we selected luteolin on the basis of its efficacy, safety profile, and similarity to genistein, which we previously showed to ameliorate other lysosomal abnormalities of cystinotic cells. Our data show that luteolin improves the autophagy-lysosome degradative pathway, is a powerful antioxidant, and has antiapoptotic properties. Moreover, luteolin stimulates endocytosis and improves the expression of the endocytic receptor megalin. CONCLUSIONS Our data show that luteolin improves defective pathways of cystinosis and has a good safety profile, and thus has potential as a treatment for nephropathic cystinosis and other renal lysosomal storage diseases.
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Affiliation(s)
- Ester De Leo
- Renal Diseases Research Unit, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Mohamed A Elmonem
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt.,Department of Pediatric Nephrology and Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
| | - Sante Princiero Berlingerio
- Department of Pediatric Nephrology and Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
| | - Marine Berquez
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | | | - Roberto Raso
- Renal Diseases Research Unit, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Francesco Bellomo
- Renal Diseases Research Unit, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Tobias Starborg
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health Sciences, University of Manchester, Manchester, UK
| | - Manoe Jacoba Janssen
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Zeinab Abbaszadeh
- Confocal Microscopy Core Facility, Research Laboratories, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Sara Cairoli
- Department of Pediatric Medicine, Laboratory of Metabolic Biochemistry Unit, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Bianca Maria Goffredo
- Department of Pediatric Medicine, Laboratory of Metabolic Biochemistry Unit, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Rosalinde Masereeuw
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Olivier Devuyst
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Martin Lowe
- Division of Molecular and Cellular Function, School of Biological Sciences, Faculty of Biology, Medicine and Health Sciences, University of Manchester, Manchester, UK
| | - Elena Levtchenko
- Department of Pediatric Nephrology and Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
| | | | - Francesco Emma
- Renal Diseases Research Unit, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy.,Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Laura Rita Rega
- Renal Diseases Research Unit, Bambino Gesù Children's Hospital, Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
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7
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Hollywood JA, Przepiorski A, D'Souza RF, Sreebhavan S, Wolvetang EJ, Harrison PT, Davidson AJ, Holm TM. Use of Human Induced Pluripotent Stem Cells and Kidney Organoids To Develop a Cysteamine/mTOR Inhibition Combination Therapy for Cystinosis. J Am Soc Nephrol 2020; 31:962-982. [PMID: 32198276 DOI: 10.1681/asn.2019070712] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 02/09/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Mutations in CTNS-a gene encoding the cystine transporter cystinosin-cause the rare, autosomal, recessive, lysosomal-storage disease cystinosis. Research has also implicated cystinosin in modulating the mTORC1 pathway, which serves as a core regulator of cellular metabolism, proliferation, survival, and autophagy. In its severest form, cystinosis is characterized by cystine accumulation, renal proximal tubule dysfunction, and kidney failure. Because treatment with the cystine-depleting drug cysteamine only slows disease progression, there is an urgent need for better treatments. METHODS To address a lack of good human-based cell culture models for studying cystinosis, we generated the first human induced pluripotent stem cell (iPSC) and kidney organoid models of the disorder. We used a variety of techniques to examine hallmarks of cystinosis-including cystine accumulation, lysosome size, the autophagy pathway, and apoptosis-and performed RNA sequencing on isogenic lines to identify differentially expressed genes in the cystinosis models compared with controls. RESULTS Compared with controls, these cystinosis models exhibit elevated cystine levels, increased apoptosis, and defective basal autophagy. Cysteamine treatment ameliorates this phenotype, except for abnormalities in apoptosis and basal autophagy. We found that treatment with everolimus, an inhibitor of the mTOR pathway, reduces the number of large lysosomes, decreases apoptosis, and activates autophagy, but it does not rescue the defect in cystine loading. However, dual treatment of cystinotic iPSCs or kidney organoids with cysteamine and everolimus corrects all of the observed phenotypic abnormalities. CONCLUSIONS These observations suggest that combination therapy with a cystine-depleting drug such as cysteamine and an mTOR pathway inhibitor such as everolimus has potential to improve treatment of cystinosis.
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Affiliation(s)
- Jennifer A Hollywood
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Aneta Przepiorski
- Department of Developmental Biology, University of Pittsburgh, Pennsylvania
| | - Randall F D'Souza
- Discipline of Nutrition, The University of Auckland, Auckland, New Zealand
| | - Sreevalsan Sreebhavan
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
| | - Ernst J Wolvetang
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Patrick T Harrison
- Department of Physiology, Biosciences Institute, University College Cork, Cork, Ireland
| | - Alan J Davidson
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Teresa M Holm
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
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8
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Rossi MN, Pascarella A, Licursi V, Caiello I, Taranta A, Rega LR, Levtchenko E, Emma F, De Benedetti F, Prencipe G. NLRP2 Regulates Proinflammatory and Antiapoptotic Responses in Proximal Tubular Epithelial Cells. Front Cell Dev Biol 2019; 7:252. [PMID: 31709256 PMCID: PMC6822264 DOI: 10.3389/fcell.2019.00252] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/11/2019] [Indexed: 11/13/2022] Open
Abstract
Nod-like Receptor Pyrin domain containing proteins (NLRPs) expressed by resident renal cells may contribute to the pathogenesis of multiple renal diseases. Cystinosis is a genetic disorder that affects kidney and particularly proximal tubular epithelial cells (PTEC). Here, we investigated the expression of NLRP family members in human control and cystinotic conditionally immortalized PTEC. Among all the NLRPs tested, we found that NLRP2 is highly expressed in cystinostic PTEC, but not in PTEC from healthy subjects. The NLRP2 overexpression was confirmed in primary PTEC and in kidney biopsies from cystinotic patients. In order to elucidate the role of NLRP2 in PTEC, we stably transfected control PTEC with an NLRP2-containing plasmid. We showed that NLRP2 markedly increases the production of several NF-κB regulated cytokines and chemokines. Accordingly, we demonstrated that NLRP2 interacts with IKKa and positively regulates the DNA-binding activity of p50 and p65 NF-κB, by modulating the p65 NF-κB phosphorylation status in Serine 536. Transcriptome analysis revealed that NLRP2 also upregulates the expression of profibrotic mediators and reduces that of several interferon-inducible genes. Finally, NLRP2 overexpression decreased the apoptotic cell rate. Consistently, silencing of NLRP2 by small-interfering RNA in cystinotic PTEC resulted in a significant decrease in cytokine and chemokine production as well as in an increase in the apoptosis rate. Altogether, our data reveals a previously unrecognized role for NLRP2 in regulating proinflammatory, profibrotic and antiapoptotic responses in PTEC, through NF-κB activation. Moreover, our findings unveil a novel potential mechanism involving NLRP2 overexpression in the pathogenesis of cystinosis.
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Affiliation(s)
- Marianna N. Rossi
- Department of Laboratories, Immuno-Rheumatology Research Area, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Antonia Pascarella
- Department of Laboratories, Immuno-Rheumatology Research Area, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Valerio Licursi
- Institute for Systems Analysis and Computer Science “Antonio Ruberti,” National Research Council, Rome, Italy
- Department of Biology and Biotechnologies “Charles Darwin,” Sapienza University of Rome, Rome, Italy
| | - Ivan Caiello
- Department of Laboratories, Immuno-Rheumatology Research Area, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Anna Taranta
- Laboratory of Nephrology, Department of Rare Diseases, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Laura R. Rega
- Laboratory of Nephrology, Department of Rare Diseases, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Elena Levtchenko
- Department of Paediatric Nephrology & Development and Regeneration, University Hospitals Leuven, Leuven, Belgium
| | - Francesco Emma
- Laboratory of Nephrology, Department of Rare Diseases, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Fabrizio De Benedetti
- Department of Laboratories, Immuno-Rheumatology Research Area, Bambino Gesù Children’s Hospital, Rome, Italy
| | - Giusi Prencipe
- Department of Laboratories, Immuno-Rheumatology Research Area, Bambino Gesù Children’s Hospital, Rome, Italy
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9
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Sumayao R, Newsholme P, McMorrow T. The Role of Cystinosin in the Intermediary Thiol Metabolism and Redox Homeostasis in Kidney Proximal Tubular Cells. Antioxidants (Basel) 2018; 7:antiox7120179. [PMID: 30513914 PMCID: PMC6315507 DOI: 10.3390/antiox7120179] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 11/22/2018] [Accepted: 11/24/2018] [Indexed: 01/26/2023] Open
Abstract
Cystinosin is a lysosomal transmembrane protein which facilitates transport of the disulphide amino acid cystine (CySS) from the lysosomes of the cell. This protein is encoded by the CTNS gene which is defective in the lysosomal storage disorder, cystinosis. Because of the apparent involvement of cystinosin in the intermediary thiol metabolism, its discovery has fuelled investigations into its role in modulating cellular redox homeostasis. The kidney proximal tubular cells (PTCs) have become the focus of various studies on cystinosin since the protein is highly expressed in these cells and kidney proximal tubular transport dysfunction is the foremost clinical manifestation of cystinosis. The lysosomal CySS pool is a major source of cytosolic cysteine (Cys), the limiting amino acid for the synthesis of an important antioxidant glutathione (GSH) via the γ-glutamyl cycle. Therefore, loss of cystinosin function is presumed to lead to cytosolic deficit of Cys which may impair GSH synthesis. However, studies using in vitro models lacking cystinosin yielded inconsistent results and failed to establish the mechanistic role of cystinosin in modulating GSH synthesis and redox homeostasis. Because of the complexity of the metabolic micro- and macro-environment in vivo, using in vitro models alone may not be able to capture the complete sequence of biochemical and physiological events that occur as a consequence of loss of cystinosin function. The coexistence of pathways for the overall handling and disposition of GSH, the modulation of CTNS gene by intracellular redox status and the existence of a non-canonical isoform of cystinosin may constitute possible rescue mechanisms in vivo to remediate redox perturbations in renal PTCs. Importantly, the mitochondria seem to play a critical role in orchestrating redox imbalances initiated by cystinosin dysfunction. Non-invasive techniques such as in vivo magnetic resonance imaging with the aid of systems biology approaches may provide invaluable mechanistic insights into the role of cystinosin in the essential intermediary thiol metabolism and in the overall regulation cellular redox homeostasis.
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Affiliation(s)
- Rodolfo Sumayao
- Chemistry Department, De La Salle University, Manila 1004, Philippines.
| | - Philip Newsholme
- School of Pharmacy and Biomedical Sciences and Curtin Health Innovation Research Institute (CHIRI), Curtin University, Perth 6845, Australia.
| | - Tara McMorrow
- Conway Institute, School of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland.
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10
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Elmonem MA, Veys K, Oliveira Arcolino F, Van Dyck M, Benedetti MC, Diomedi-Camassei F, De Hertogh G, van den Heuvel LP, Renard M, Levtchenko E. Allogeneic HSCT transfers wild-type cystinosin to nonhematological epithelial cells in cystinosis: First human report. Am J Transplant 2018; 18:2823-2828. [PMID: 30030899 DOI: 10.1111/ajt.15029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 06/28/2018] [Accepted: 07/12/2018] [Indexed: 01/25/2023]
Abstract
Cystinosis is an autosomal recessive lysosomal storage disorder characterized by the defective transport of the amino acid cystine out of the lysosome due to a deficiency of cystinosin, the lysosomal cystine transporter. Patients have lysosomal cystine accumulation in various tissues, leading to cellular stress and damage, particularly in the kidney, cornea, and other extrarenal tissues. Cysteamine, a cystine-depleting agent, improves survival and delays the progression of disease, but it does not prevent the development of either renal failure or extrarenal complications. Furthermore, the drug has severe adverse effects that significantly reduce patient compliance. Allogeneic hematopoietic stem cell transplantation (HSCT) is currently established as a therapeutic option for many inborn errors of metabolism, where the main pathologic driving factor is an enzyme deficiency. Recent studies in the cystinosis mouse-model suggested that HSCT could be a curative treatment alternative to cysteamine therapy. We treated a 16-year-old boy who had infantile cystinosis and side effects of cysteamine therapy with HSCT. We were able to demonstrate successful transfer of the wild-type cystinosin protein and CTNS mRNA to nonhematological epithelial cells in the recipient, as well as a decrease in the tissue cystine-crystal burden. This is the first report of allogeneic HSCT in a patient with cystinosis, the prototype of lysosomal membrane-transporter disorders.
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Affiliation(s)
- Mohamed A Elmonem
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven - University of Leuven, Leuven, Belgium.,Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Koenraad Veys
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven - University of Leuven, Leuven, Belgium
| | - Fanny Oliveira Arcolino
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven - University of Leuven, Leuven, Belgium
| | - Maria Van Dyck
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven - University of Leuven, Leuven, Belgium
| | - Maria C Benedetti
- Department of Laboratories, Pathology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | | | - Gert De Hertogh
- Department of Translational Cell and Tissue Research, KU Leuven - University of Leuven, Leuven, Belgium
| | - Lambertus P van den Heuvel
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven - University of Leuven, Leuven, Belgium.,Department of Pediatric Nephrology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marleen Renard
- Department of Pediatric Hematology and Oncology, KU Leuven - University of Leuven, Leuven, Belgium
| | - Elena Levtchenko
- Department of Pediatric Nephrology & Development and Regeneration, University Hospitals Leuven, KU Leuven - University of Leuven, Leuven, Belgium
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11
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Bellomo F, Signorile A, Tamma G, Ranieri M, Emma F, De Rasmo D. Impact of atypical mitochondrial cyclic-AMP level in nephropathic cystinosis. Cell Mol Life Sci 2018; 75:3411-3422. [PMID: 29549422 PMCID: PMC11105431 DOI: 10.1007/s00018-018-2800-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 02/20/2018] [Accepted: 03/14/2018] [Indexed: 02/06/2023]
Abstract
Nephropathic cystinosis (NC) is a rare disease caused by mutations in the CTNS gene encoding for cystinosin, a lysosomal transmembrane cystine/H+ symporter, which promotes the efflux of cystine from lysosomes to cytosol. NC is the most frequent cause of Fanconi syndrome (FS) in young children, the molecular basis of which is not well established. Proximal tubular cells have very high metabolic rate due to the active transport of many solutes. Not surprisingly, mitochondrial disorders are often characterized by FS. A similar mechanism may also apply to NC. Because cAMP has regulatory properties on mitochondrial function, we have analyzed cAMP levels and mitochondrial targets in CTNS-/- conditionally immortalized proximal tubular epithelial cells (ciPTEC) carrying the classical homozygous 57-kb deletion (delCTNS-/-) or with compound heterozygous loss-of-function mutations (mutCTNS-/-). Compared to wild-type cells, cystinotic cells had significantly lower mitochondrial cAMP levels (delCTNS-/- ciPTEC by 56% ± 10.5, P < 0.0001; mutCTNS-/- by 26% ± 4.3, P < 0.001), complex I and V activities, mitochondrial membrane potential, and SIRT3 protein levels, which were associated with increased mitochondrial fragmentation. Reduction of complex I and V activities was associated with lower expression of part of their subunits. Treatment with the non-hydrolysable cAMP analog 8-Br-cAMP restored mitochondrial potential and corrected mitochondria morphology. Treatment with cysteamine, which reduces the intra-lysosomal cystine, was able to restore mitochondrial cAMP levels, as well as most other abnormal mitochondrial findings. These observations were validated in CTNS-silenced HK-2 cells, indicating a pivotal role of mitochondrial cAMP in the proximal tubular dysfunction observed in NC.
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Affiliation(s)
- Francesco Bellomo
- Laboratory of Nephrology, Department of Rare Diseases, Bambino Gesù Children's Hospital, Viale di S. Paolo, 15, 00149, Rome, Italy.
| | - Anna Signorile
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", Policlinico, Piazza G. Cesare, 11, 70124, Bari, Italy
| | - Grazia Tamma
- Department of Bioscience, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Marianna Ranieri
- Department of Bioscience, Biotechnologies and Biopharmaceutics, University of Bari "Aldo Moro", Bari, Italy
| | - Francesco Emma
- Laboratory of Nephrology, Department of Rare Diseases, Bambino Gesù Children's Hospital, Viale di S. Paolo, 15, 00149, Rome, Italy
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children's Hospital, Rome, Italy
| | - Domenico De Rasmo
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari "Aldo Moro", Policlinico, Piazza G. Cesare, 11, 70124, Bari, Italy.
- Institute of Biomembrane, Bioenergetics and Molecular Biotechnology (IBIOM), National Research Council (CNR), Bari, Italy.
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12
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Cherqui S, Courtoy PJ. The renal Fanconi syndrome in cystinosis: pathogenic insights and therapeutic perspectives. Nat Rev Nephrol 2016; 13:115-131. [PMID: 27990015 DOI: 10.1038/nrneph.2016.182] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cystinosis is an autosomal recessive metabolic disease that belongs to the family of lysosomal storage disorders. It is caused by a defect in the lysosomal cystine transporter, cystinosin, which results in an accumulation of cystine in all organs. Despite the ubiquitous expression of cystinosin, a renal Fanconi syndrome is often the first manifestation of cystinosis, usually presenting within the first year of life and characterized by the early and severe dysfunction of proximal tubule cells, highlighting the unique vulnerability of this cell type. The current therapy for cystinosis, cysteamine, facilitates lysosomal cystine clearance and greatly delays progression to kidney failure but is unable to correct the Fanconi syndrome. This Review summarizes decades of studies that have fostered a better understanding of the pathogenesis of the renal Fanconi syndrome associated with cystinosis. These studies have unraveled some of the early molecular changes that occur before the onset of tubular atrophy and identified a role for cystinosin beyond cystine transport, in endolysosomal trafficking and proteolysis, lysosomal clearance, autophagy and the regulation of energy balance. These studies have also led to the identification of new potential therapeutic targets and here, we outline the potential role of stem cell therapy for cystinosis and provide insights into the mechanism of haematopoietic stem cell-mediated kidney protection.
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Affiliation(s)
- Stephanie Cherqui
- Department of Pediatrics, Division of Genetics, University of California San Diego, 9500 Gilman Drive, MC 0734, La Jolla, California 92093-0734, USA
| | - Pierre J Courtoy
- Cell biology, de Duve Institute and Université catholique de Louvain, UCL-Brussels, 75 Avenue Hippocrate, B-1200 Brussels, Belgium
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13
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Ramazani Y, Levtchenko EN, Van Den Heuvel L, Van Schepdael A, Paul P, Ivanova EA, Pastore A, Hartman TM, Price NPJ. Evaluation of carbohydrate-cysteamine thiazolidines as pro-drugs for the treatment of cystinosis. Carbohydr Res 2016; 439:9-15. [PMID: 28033491 DOI: 10.1016/j.carres.2016.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 12/09/2016] [Accepted: 12/12/2016] [Indexed: 10/20/2022]
Abstract
Cystinosis is a genetic disorder caused by malfunction of cystinosin and is characterized by accumulation of cystine. Cysteamine, the medication used in cystinosis, causes halitosis resulting in poor patient compliance. Halitosis is mainly caused by the formation of dimethylsulfide as the final product in the cysteamine metabolism pathway. We have synthesized carbohydrate-cysteamine thiazolidines, and hypothesized that the hydrolytic breakdown of cysteamine-thiazolidines can result in free cysteamine being released in target organs. To examine our hypothesis, we tested these analogs in vitro in patient-derived fibroblasts. Cystinotic fibroblasts were treated with different concentrations of arabinose-cysteamine, glucose-cysteamine and maltose-cysteamine. We demonstrated that the analogs break down into cysteamine extracellularly and might therefore not be fully taken up by the cells under the form of the pro-drug. Potential modifications of the analogs that enable their intracellular rather than extracellular breakdown, is necessary to pursue the potential of these analogs as pro-drugs.
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Affiliation(s)
- Yasaman Ramazani
- Department of Pediatric Nephrology and Growth and Regeneration, University Hospitals Leuven and University of Leuven, UZ Herestraat 49, Box 817, 3000 Leuven, Belgium
| | - Elena N Levtchenko
- Department of Pediatric Nephrology and Growth and Regeneration, University Hospitals Leuven and University of Leuven, UZ Herestraat 49, Box 817, 3000 Leuven, Belgium
| | - Lambertus Van Den Heuvel
- Department of Pediatric Nephrology, Radboud University Medical Center Nijmegen, Nijmegen, The Netherlands
| | - Ann Van Schepdael
- Department of Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, University of Leuven, O&N II Herestraat 49, Box 923, 3000 Leuven, Belgium
| | - Prasanta Paul
- Department of Pharmaceutical and Pharmacological Sciences, Pharmaceutical Analysis, University of Leuven, O&N II Herestraat 49, Box 923, 3000 Leuven, Belgium
| | - Ekaterina A Ivanova
- Department of Pediatric Nephrology and Growth and Regeneration, University Hospitals Leuven and University of Leuven, UZ Herestraat 49, Box 817, 3000 Leuven, Belgium
| | - Anna Pastore
- Laboratory of Metabolomics and Proteomics Bambino Gesu Children's Hospital, IRCCS, Piazza S. Onofrio 4, 00165, Rome, Italy
| | - Trina M Hartman
- Agricultural Research Service, U.S. Department of Agriculture, National Center for Agricultural Utilization Research, Peoria, IL 61604, USA
| | - Neil P J Price
- Agricultural Research Service, U.S. Department of Agriculture, National Center for Agricultural Utilization Research, Peoria, IL 61604, USA.
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14
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Abstract
SIGNIFICANCE A common link between all forms of acute and chronic kidney injuries, regardless of species, is enhanced generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) during injury/disease progression. While low levels of ROS and RNS are required for prosurvival signaling, cell proliferation and growth, and vasoreactivity regulation, an imbalance of ROS and RNS generation and elimination leads to inflammation, cell death, tissue damage, and disease/injury progression. RECENT ADVANCES Many aspects of renal oxidative stress still require investigation, including clarification of the mechanisms which prompt ROS/RNS generation and subsequent renal damage. However, we currently have a basic understanding of the major features of oxidative stress pathology and its link to kidney injury/disease, which this review summarizes. CRITICAL ISSUES The review summarizes the critical sources of oxidative stress in the kidney during injury/disease, including generation of ROS and RNS from mitochondria, NADPH oxidase, and inducible nitric oxide synthase. The review next summarizes the renal antioxidant systems that protect against oxidative stress, including superoxide dismutase and catalase, the glutathione and thioredoxin systems, and others. Next, we describe how oxidative stress affects kidney function and promotes damage in every nephron segment, including the renal vessels, glomeruli, and tubules. FUTURE DIRECTIONS Despite the limited success associated with the application of antioxidants for treatment of kidney injury/disease thus far, preventing the generation and accumulation of ROS and RNS provides an ideal target for potential therapeutic treatments. The review discusses the shortcomings of antioxidant treatments previously used and the potential promise of new ones. Antioxid. Redox Signal. 25, 119-146.
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Affiliation(s)
- Brian B Ratliff
- 1 Department of Medicine, Renal Research Institute , New York Medical College, Valhalla, New York.,2 Department of Physiology, Renal Research Institute , New York Medical College, Valhalla, New York
| | - Wasan Abdulmahdi
- 2 Department of Physiology, Renal Research Institute , New York Medical College, Valhalla, New York
| | - Rahul Pawar
- 1 Department of Medicine, Renal Research Institute , New York Medical College, Valhalla, New York
| | - Michael S Wolin
- 2 Department of Physiology, Renal Research Institute , New York Medical College, Valhalla, New York
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15
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Controversies and research agenda in nephropathic cystinosis: conclusions from a “Kidney Disease: Improving Global Outcomes” (KDIGO) Controversies Conference. Kidney Int 2016; 89:1192-203. [DOI: 10.1016/j.kint.2016.01.033] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 01/22/2016] [Accepted: 01/28/2016] [Indexed: 01/19/2023]
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16
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Ivanova EA, van den Heuvel LP, Elmonem MA, De Smedt H, Missiaen L, Pastore A, Mekahli D, Bultynck G, Levtchenko EN. Altered mTOR signalling in nephropathic cystinosis. J Inherit Metab Dis 2016; 39:457-464. [PMID: 26909499 DOI: 10.1007/s10545-016-9919-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/22/2016] [Accepted: 02/02/2016] [Indexed: 11/27/2022]
Abstract
Lysosomes play a central role in regulating autophagy via activation of mammalian target of rapamycin complex 1 (mTORC1). We examined mTORC1 signalling in the lysosomal storage disease nephropathic cystinosis (MIM 219800), in which accumulation of autophagy markers has been previously demonstrated. Cystinosis is caused by mutations in the lysosomal cystine transporter cystinosin and initially affects kidney proximal tubules causing renal Fanconi syndrome, followed by a gradual development of end-stage renal disease and extrarenal complications. Using proximal tubular kidney cells obtained from healthy donors and from cystinotic patients, we demonstrate that cystinosin deficiency is associated with a perturbed mTORC1 signalling, delayed reactivation of mTORC1 after starvation and abnormal lysosomal retention of mTOR during starvation. These effects could not be reversed by treatment with cystine-depleting drug cysteamine. Altered mTORC1 signalling can contribute to the development of proximal tubular dysfunction in cystinosis and points to new possibilities in therapeutic intervention through modulation of mTORC-dependent signalling cascades.
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Affiliation(s)
- Ekaterina A Ivanova
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
| | - Lambertus P van den Heuvel
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
- Department of Pediatric Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mohamed A Elmonem
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Humbert De Smedt
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Anna Pastore
- Laboratory of Proteomics and Metabolomics, Children's Hospital and Research Institute "Bambino Gesù" IRCCS, Rome, Italy
| | - Djalila Mekahli
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
| | - Greet Bultynck
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Elena N Levtchenko
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium.
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17
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Sumayao R, McEvoy B, Newsholme P, McMorrow T. Lysosomal cystine accumulation promotes mitochondrial depolarization and induction of redox-sensitive genes in human kidney proximal tubular cells. J Physiol 2016; 594:3353-70. [PMID: 26915455 DOI: 10.1113/jp271858] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 02/02/2016] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Cystine is a disulphide amino acid that is normally generated in the lysosomes by the breakdown of cystine-containing proteins. Previously, we demonstrated that lysosomal cystine accumulation in kidney proximal tubular epithelial cells (PTECs) dramatically reduced glutathione (GSH) levels, which may result in the disruption of cellular redox balance. In the present study, we show that lysosomal cystine accumulation following CTNS gene silencing in kidney PTECs resulted in elevated intracellular reactive oxygen species production, reduced antioxidant capacity, induction of redox-sensitive proteins, altered mitochondrial integrity and augmented cell death. These alterations may represent different facets of a unique cascade leading to tubular dysfunction initiated by lysosomal cystine accumulation and may present a clear disadvantage for cystinotic PTECs in vivo. Cystine depletion by cysteamine afforded cytoprotection in CTNS knockdown cells by reducing oxidative stress, normalizing intracellular GSH and ATP content, and preserving cell viability. ABSTRACT Cystine is a disulphide amino acid that is normally generated within the lysosomes through lysosomal-based protein degradation and via extracellular uptake of free cystine. In the autosomal recessive disorder, cystinosis, a defect in the CTNS gene results in excessive lysosomal accumulation of cystine, with early kidney failure a hallmark of the disease. Previously, we demonstrated that silencing of the CTNS gene in kidney proximal tubular epithelial cells (PTECs) resulted in an increase in intracellular cystine concentration coupled with a dramatic reduction in the total GSH content. Because of the crucial role of GSH in maintaining the redox status and viability of kidney PTECs, we assessed the effects of CTNS knockdown-induced lysosomal cystine accumulation on intracellular reactive oxygen species (ROS) production, activity of classical redox-sensitive genes, mitochondrial integrity and cell viability. Our results showed that lysosomal cystine accumulation increased ROS production and solicitation to oxidative stress (OS). This was associated with the induction of classical redox-sensitive proteins, NF-κB, NRF2, HSP32 and HSP70. Cystine-loaded PTECs also displayed depolarized mitochondria, reduced ATP content and augmented apoptosis. Treatment of CTNS knockdown PTECs with the cystine-depleting agent cysteamine resulted in the normalization of OS index, increased GSH and ATP content, and preservation of cell viability. Taken together, the alterations observed in cystinotic cells may represent different facets of a cascade leading to tubular dysfunction and, in combination with cysteamine therapy, may offer a novel link for the attenuation of renal injury and preservation of functions of other organs affected in cystinosis.
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Affiliation(s)
- Rodolfo Sumayao
- Conway Institute, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Bernadette McEvoy
- Conway Institute, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Philip Newsholme
- School of Biomedical Sciences, CHIRI Biosciences Research Precinct and Faculty of Health Sciences, Curtin University, Perth, Western Australia
| | - Tara McMorrow
- Conway Institute, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
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18
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Synthesis of diacylated γ-glutamyl-cysteamine prodrugs, and in vitro evaluation of their cytotoxicity and intracellular delivery of cysteamine. Eur J Med Chem 2016; 109:206-15. [DOI: 10.1016/j.ejmech.2015.12.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/28/2015] [Accepted: 12/14/2015] [Indexed: 11/20/2022]
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19
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McEvoy B, Sumayao R, Slattery C, McMorrow T, Newsholme P. Cystine accumulation attenuates insulin release from the pancreatic β-cell due to elevated oxidative stress and decreased ATP levels. J Physiol 2015; 593:5167-82. [PMID: 26482480 DOI: 10.1113/jp271237] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 10/13/2015] [Indexed: 12/26/2022] Open
Abstract
The pancreatic β-cell has reduced antioxidant defences making it more susceptible to oxidative stress. In cystinosis, a lysosomal storage disorder, an altered redox state may contribute to cellular dysfunction. This rare disease is caused by an abnormal lysosomal cystine transporter, cystinosin, which causes excessive accumulation of cystine in the lysosome. Cystinosis associated kidney damage and dysfunction leads to the Fanconi syndrome and ultimately end-stage renal disease. Following kidney transplant, cystine accumulation in other organs including the pancreas leads to multi-organ dysfunction. In this study, a Ctns gene knockdown model of cystinosis was developed in the BRIN-BD11 rat clonal pancreatic β-cell line using Ctns-targeting siRNA. Additionally there was reduced cystinosin expression, while cell cystine levels were similarly elevated to the cystinotic state. Decreased levels of chronic (24 h) and acute (20 min) nutrient-stimulated insulin secretion were observed. This decrease may be due to depressed ATP generation particularly from glycolysis. Increased ATP production and the ATP/ADP ratio are essential for insulin secretion. Oxidised glutathione levels were augmented, resulting in a lower [glutathione/oxidised glutathione] redox potential. Additionally, the mitochondrial membrane potential was reduced, apoptosis levels were elevated, as were markers of oxidative stress, including reactive oxygen species, superoxide and hydrogen peroxide. Furthermore, the basal and activated phosphorylated forms of the redox-sensitive transcription factor NF-κB were increased in cells with silenced Ctns. From this study, the cystinotic-like pancreatic β-cell model demonstrated that the altered oxidative status of the cell, resulted in depressed mitochondrial function and pathways of ATP production, causing reduced nutrient-stimulated insulin secretion.
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Affiliation(s)
- Bernadette McEvoy
- Conway Institute, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Rodolfo Sumayao
- Conway Institute, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Craig Slattery
- Conway Institute, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Tara McMorrow
- Conway Institute, School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Philip Newsholme
- School of Biomedical Sciences, CHIRI Biosciences Research Precinct and Faculty of Health Sciences, Curtin University, Perth, Australia
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20
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Nesterova G, Williams C, Bernardini I, Gahl WA. Cystinosis: renal glomerular and renal tubular function in relation to compliance with cystine-depleting therapy. Pediatr Nephrol 2015; 30:945-51. [PMID: 25526929 DOI: 10.1007/s00467-014-3018-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/12/2014] [Accepted: 11/13/2014] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND OBJECTIVES Nephropathic cystinosis is a lysosomal storage disorder characterized by renal tubular Fanconi syndrome in infancy and glomerular damage leading to renal failure at ∼10 years of age. Therapy with the cystine-depleting agent cysteamine postpones renal failure, but the degree of compliance with this treatment has not been correlated with preservation of kidney function. METHODS We assessed leucocyte cystine depletion by cysteamine and created the composite compliance score that incorporates the extent of leucocyte cystine depletion, as well as duration of cysteamine treatment, into a single integer. Age at renal failure was used to gauge preservation of renal function, and the Fanconi syndrome index (FSI), a measure of aminoaciduria, was used to assess renal tubular Fanconi syndrome. RESULTS Age at renal failure varied directly and linearly with the composite compliance score (y = 0.3x +8.8; R(2) = 0.61). The slope indicated that for every year of excellent cystine depletion, nearly 1 year of renal function was preserved. Age at renal failure correlated roughly with mean leucocyte cystine level, but not with mean cysteamine dosage. There was no correlation between the FSI and the composite compliance score. CONCLUSIONS Greater compliance with oral cysteamine therapy yields greater preservation of renal glomerular, but not tubular, function. Oral cysteamine therapy should be given at the maximum tolerated dose, within the recommended limits.
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Affiliation(s)
- Galina Nesterova
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA,
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21
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Endo-lysosomal dysfunction in human proximal tubular epithelial cells deficient for lysosomal cystine transporter cystinosin. PLoS One 2015; 10:e0120998. [PMID: 25811383 PMCID: PMC4374958 DOI: 10.1371/journal.pone.0120998] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 02/09/2015] [Indexed: 12/11/2022] Open
Abstract
Nephropathic cystinosis is a lysosomal storage disorder caused by mutations in the CTNS gene encoding cystine transporter cystinosin that results in accumulation of amino acid cystine in the lysosomes throughout the body and especially affects kidneys. Early manifestations of the disease include renal Fanconi syndrome, a generalized proximal tubular dysfunction. Current therapy of cystinosis is based on cystine-lowering drug cysteamine that postpones the disease progression but offers no cure for the Fanconi syndrome. We studied the mechanisms of impaired reabsorption in human proximal tubular epithelial cells (PTEC) deficient for cystinosin and investigated the endo-lysosomal compartments of cystinosin-deficient PTEC by means of light and electron microscopy. We demonstrate that cystinosin-deficient cells had abnormal shape and distribution of the endo-lysosomal compartments and impaired endocytosis, with decreased surface expression of multiligand receptors and delayed lysosomal cargo processing. Treatment with cysteamine improved surface expression and lysosomal cargo processing but did not lead to a complete restoration and had no effect on the abnormal morphology of endo-lysosomal compartments. The obtained results improve our understanding of the mechanism of proximal tubular dysfunction in cystinosis and indicate that impaired protein reabsorption can, at least partially, be explained by abnormal trafficking of endosomal vesicles.
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22
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Di Mise A, Tamma G, Ranieri M, Svelto M, Heuvel BVD, Levtchenko EN, Valenti G. Conditionally immortalized human proximal tubular epithelial cells isolated from the urine of a healthy subject express functional calcium-sensing receptor. Am J Physiol Renal Physiol 2015; 308:F1200-6. [PMID: 25656364 DOI: 10.1152/ajprenal.00352.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 02/03/2015] [Indexed: 02/08/2023] Open
Abstract
The calcium-sensing receptor (CaSR) is a G protein-coupled receptor, which plays an essential role in regulating Ca(2+) homeostasis. Here we show that conditionally immortalized proximal tubular epithelial cell line (ciPTEC) obtained by immortalizing and subcloning cells exfoliated in the urine of a healthy subject expresses functional endogenous CaSR. Immunolocalization studies of polarized ciPTEC revealed the apical localization of the receptor. By Western blotting of ciPTEC lysates, both monomeric and dimeric forms of CaSR at 130 and ∼250 kDa, respectively, were detected. Functional studies indicated that both external calcium and the positive CaSR allosteric modulator, NPS-R568, induced a significant increase in cytosolic calcium, proving a high sensitivity of the endogenous receptor to its agonists. Calcium depletion from the endoplasmic reticulum using cyclopiazonic acid abolished the increase in cytosolic calcium elicited by NPS-R568, confirming calcium exit from intracellular stores. Activation of CaSR by NPS-R significantly reduced the increase in cAMP elicited by forskolin (FK), a direct activator of adenylate cyclase, further confirming the functional expression of the receptor in this cell line. CaSR expressed in ciPTEC was found to interact with Gq as a downstream effector, which in turn can cause release of calcium from intracellular stores via phospholipase C activation. We conclude that human proximal tubular ciPTEC express functional CaSR and respond to its activation with a release of calcium from intracellular stores. These cell lines represent a valuable tool for research into the disorder associated with gain or loss of function of the CaSR by producing cell lines from patients.
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Affiliation(s)
- Annarita Di Mise
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Aldo Moro, Italy
| | - Grazia Tamma
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Aldo Moro, Italy
| | - Marianna Ranieri
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Aldo Moro, Italy
| | - Maria Svelto
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Aldo Moro, Italy; Center of Excellence in Comparative Genomics(CEGBA), Bari, Italy
| | - Bert van den Heuvel
- Department of Pediatric Nephrology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; and
| | - Elena N Levtchenko
- Department of Pediatric Nephrology, University Hospital Gasthuisberg, Leuven, Belgium
| | - Giovanna Valenti
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Aldo Moro, Italy; Center of Excellence in Comparative Genomics(CEGBA), Bari, Italy;
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Knops N, van den Heuvel LP, Masereeuw R, Bongaers I, de Loor H, Levtchenko E, Kuypers D. The Functional Implications of Common Genetic Variation in CYP3A5 and ABCB1 in Human Proximal Tubule Cells. Mol Pharm 2015; 12:758-68. [DOI: 10.1021/mp500590s] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Noël Knops
- Department of Pediatric Nephrology and Solid Organ Transplantation and ‡Department of Nephrology
and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
- Laboratory for Pediatrics, Department of Development & Regeneration and ⊥Laboratory of Nephrology, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Genetic, Endocrine, and Metabolic Disorders and ∥Department of Pharmacology
and Toxicology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Lambertus P. van den Heuvel
- Department of Pediatric Nephrology and Solid Organ Transplantation and ‡Department of Nephrology
and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
- Laboratory for Pediatrics, Department of Development & Regeneration and ⊥Laboratory of Nephrology, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Genetic, Endocrine, and Metabolic Disorders and ∥Department of Pharmacology
and Toxicology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Rosalinde Masereeuw
- Department of Pediatric Nephrology and Solid Organ Transplantation and ‡Department of Nephrology
and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
- Laboratory for Pediatrics, Department of Development & Regeneration and ⊥Laboratory of Nephrology, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Genetic, Endocrine, and Metabolic Disorders and ∥Department of Pharmacology
and Toxicology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Inge Bongaers
- Department of Pediatric Nephrology and Solid Organ Transplantation and ‡Department of Nephrology
and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
- Laboratory for Pediatrics, Department of Development & Regeneration and ⊥Laboratory of Nephrology, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Genetic, Endocrine, and Metabolic Disorders and ∥Department of Pharmacology
and Toxicology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Henriëtte de Loor
- Department of Pediatric Nephrology and Solid Organ Transplantation and ‡Department of Nephrology
and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
- Laboratory for Pediatrics, Department of Development & Regeneration and ⊥Laboratory of Nephrology, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Genetic, Endocrine, and Metabolic Disorders and ∥Department of Pharmacology
and Toxicology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Elena Levtchenko
- Department of Pediatric Nephrology and Solid Organ Transplantation and ‡Department of Nephrology
and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
- Laboratory for Pediatrics, Department of Development & Regeneration and ⊥Laboratory of Nephrology, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Genetic, Endocrine, and Metabolic Disorders and ∥Department of Pharmacology
and Toxicology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Dirk Kuypers
- Department of Pediatric Nephrology and Solid Organ Transplantation and ‡Department of Nephrology
and Renal Transplantation, University Hospitals Leuven, B-3000 Leuven, Belgium
- Laboratory for Pediatrics, Department of Development & Regeneration and ⊥Laboratory of Nephrology, KU Leuven, 3000 Leuven, Belgium
- Laboratory for Genetic, Endocrine, and Metabolic Disorders and ∥Department of Pharmacology
and Toxicology, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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24
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Surendran K, Vitiello SP, Pearce DA. Lysosome dysfunction in the pathogenesis of kidney diseases. Pediatr Nephrol 2014; 29:2253-61. [PMID: 24217784 PMCID: PMC4018427 DOI: 10.1007/s00467-013-2652-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 09/29/2013] [Accepted: 10/01/2013] [Indexed: 12/18/2022]
Abstract
The lysosome, an organelle central to macromolecule degradation and recycling, plays a pivotal role in normal cell processes, ranging from autophagy to redox regulation. Not surprisingly, lysosomes are an integral part of the renal epithelial molecular machinery that facilitates normal renal physiology. Two inherited diseases that manifest as kidney dysfunction are Fabry's disease and cystinosis, each of which is caused by a primary biochemical defect at the lysosome resulting from loss-of-function mutations in genes that encode lysosomal proteins. The functions of the lysosomes in the kidney and how lysosomal dysfunction might contribute to Fabry's disease and cystinosis are discussed. Unlike most other pediatric renal diseases, therapies are available for Fabry's disease and cystinosis, but require early diagnosis. Recent analysis of ceroid neuronal lipofuscinosis type 3 (Cln3) null mice, a mouse model of lysosomal disease that is primarily associated with neurological deficits, revealed renal functional abnormalities. As current and future therapeutics increase the life-span of those suffering from diseases like neuronal ceroid lipofuscinosis, it remains a distinct possibility that many more lysosomal disorders that primarily manifest as infant and juvenile neurodegenerative diseases may also include renal disease phenotypes.
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Affiliation(s)
- Kameswaran Surendran
- Sanford Children’s Health Research Center, Sanford Research/USD, Sioux Falls, SD 57104, USA,Department of Pediatrics, Sanford School of Medicine, Sioux Falls, SD 57104, USA
| | - Seasson P. Vitiello
- Sanford Children’s Health Research Center, Sanford Research/USD, Sioux Falls, SD 57104, USA,Augustana College, Sioux Falls, SD
| | - David A. Pearce
- Sanford Children’s Health Research Center, Sanford Research/USD, Sioux Falls, SD 57104, USA,Department of Pediatrics, Sanford School of Medicine, Sioux Falls, SD 57104, USA,Corresponding Author: David A. Pearce, Sanford Research/USD, 2301 East 60th Street North, Sioux Falls, SD, 57104-0589, Telephone: 605 312-6004, FAX: 605 312-6071,
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25
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Pache de Faria Guimaraes L, Seguro AC, Shimizu MHM, Lopes Neri LA, Sumita NM, de Bragança AC, Aparecido Volpini R, Cunha Sanches TR, Macaferri da Fonseca FA, Moreira Filho CA, Vaisbich MH. N-acetyl-cysteine is associated to renal function improvement in patients with nephropathic cystinosis. Pediatr Nephrol 2014; 29:1097-102. [PMID: 24326786 DOI: 10.1007/s00467-013-2705-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 10/25/2013] [Accepted: 11/11/2013] [Indexed: 01/02/2023]
Abstract
BACKGROUND Nephropathic cystinosis is an autosomal recessive systemic severe disease characterized by intralysosomal cystine storage. Cysteamine is an essential component of treatment. There is solid evidence that cystine accumulation itself is not responsible for all abnormalities in cystinosis; there is also a deficiency of glutathione in the cytosol. Patients with cystinosis can be more susceptible to oxidative stress. CASE-DIAGNOSIS/TREATMENT The patient cohort comprised 23 cystinosis patients (16 males) aged <18 years (mean age 8.0 ± 3.6 years) with chronic kidney disease class I-IV with good adherence to treatment, including cysteamine. Oxidative stress was evaluated based on the levels of serum thiobarbituric acid-reactive substances (TBARS), and renal function was evaluated based on serum creatinine and cystatin C levels and creatinine clearance (Schwartz formula). N-Acetylcysteine (NAC), an antioxidant drug was given to all patients for 3 months (T1) at 25 mg/kg/day divided in three doses per day. The measured values at just before the initiation of NAC treatment (T0) served as the control for each patient. RESULTS Median serum TBARS levels at T0 and T1 were 6.92 (range 3.3-29.0) and 1.7 (0.6-7.2) nmol/mL, respectively (p < 0.0001). In terms of renal function at T0 and T1, serum creatinine levels (1.1 ± 0.5 vs. 0.9 ± 0.5 mg/dL, respectively; p < 0.0001), creatinine clearance (69.7 ± 32.2 vs. T1 = 78.5 ± 33.9 mL/min/1.73 m(2), respectively; p = 0.006), and cystatin c level (1.33 ± 0.53 vs. 1.15 ± 0.54 mg/l, respectively; p = 0.0057) were all significantly different at these two time points. Serum creatinine measurements at 6 (T -6) and 3 months (T -3) before NAC initiation and at 3 (T +3) and 6 months (T +6) after NAC had been withdrawn were also evaluated. CONCLUSION During the 3-month period that our 23 cystinosis patients were treated with NAC, oxidative stress was reduced and renal function significantly improved. No side-effects were detected. Larger and controlled studies are needed to confirm these findings.
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Affiliation(s)
- Luciana Pache de Faria Guimaraes
- Pediatric Nephrology Unit, Instituto da Criança, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil
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26
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Besouw MTP, Emma F, Levtchenko EN. Management of nephropathic cystinosis. Expert Opin Orphan Drugs 2013. [DOI: 10.1517/21678707.2013.855634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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27
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Sumayao R, McEvoy B, Martin-Martin N, McMorrow T, Newsholme P. Cystine dimethylester loading promotes oxidative stress and a reduction in ATP independent of lysosomal cystine accumulation in a human proximal tubular epithelial cell line. Exp Physiol 2013; 98:1505-17. [PMID: 23813804 DOI: 10.1113/expphysiol.2013.073809] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Using the cystine dimethylester (CDME) loading technique to achieve elevated lysosomal cystine levels, ATP depletion has previously been postulated to be responsible for the renal dysfunction in cystinosis, a genetic disorder characterized by an excessive accumulation of cystine in the lysosomes. However, this is unlikely to be the sole factor responsible for the complexity of cell stress associated with cystinosis. Moreover, CDME has been shown to induce a direct toxic effect on mitochondrial ATP generation. Using a human-derived proximal tubular epithelial cell line, we compared the effects of CDME loading with small interfering RNA-mediated cystinosin, lysosomal cystine transporter (CTNS) gene silencing on glutathione redox status, reactive oxygen species levels, oxidative stress index, antioxidant enzyme activities and ATP generating capacity. The CDME-loaded cells displayed increased total glutathione content, extensive superoxide depletion, augmented oxidative stress index, decreased catalase activity, normal superoxide dismutase activity and compromised ATP generation. In contrast, cells subjected to CTNS gene inhibition demonstrated decreased total glutathione content, increased superoxide levels, unaltered oxidative stress index, unaltered catalase activity, induction of superoxide dismutase activity and normal ATP generation. Our data indicate that many CDME-induced effects are independent of lysosomal cystine accumulation, which further underscores the limited value of CDME loading for studying the pathogenesis of cystinosis. CTNS gene inhibition, which results in intracellular cystine accumulation, is a more realistic approach for investigating biochemical alterations in cystinosis.
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Affiliation(s)
- Rodolfo Sumayao
- P. Newsholme: School of Biomedical Sciences, Building 308, Room 122, CHIRI and Faculty of Health Sciences, GPO Box U1987, Curtin University, Perth, WA 6845, Australia.
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28
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Mekahli D, Sammels E, Luyten T, Welkenhuyzen K, van den Heuvel LP, Levtchenko EN, Gijsbers R, Bultynck G, Parys JB, De Smedt H, Missiaen L. Polycystin-1 and polycystin-2 are both required to amplify inositol-trisphosphate-induced Ca2+ release. Cell Calcium 2012; 51:452-8. [PMID: 22456092 DOI: 10.1016/j.ceca.2012.03.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 02/27/2012] [Accepted: 03/02/2012] [Indexed: 12/31/2022]
Abstract
Autosomal dominant polycystic kidney disease is caused by loss-of-function mutations in the PKD1 or PKD2 genes encoding respectively polycystin-1 and polycystin-2. Polycystin-2 stimulates the inositol trisphosphate (IP(3)) receptor (IP(3)R), a Ca(2+)-release channel in the endoplasmic reticulum (ER). The effect of ER-located polycystin-1 is less clear. Polycystin-1 has been reported both to stimulate and to inhibit the IP(3)R. We now studied the effect of polycystin-1 and of polycystin-2 on the IP(3)R activity under conditions where the cytosolic Ca(2+) concentration was kept constant and the reuptake of released Ca(2+) was prevented. We also studied the interdependence of the interaction of polycystin-1 and polycystin-2 with the IP(3)R. The experiments were done in conditionally immortalized human proximal-tubule epithelial cells in which one or both polycystins were knocked down using lentiviral vectors containing miRNA-based short hairpins. The Ca(2+) release was induced in plasma membrane-permeabilized cells by various IP(3) concentrations at a fixed Ca(2+) concentration under unidirectional (45)Ca(2+)-efflux conditions. We now report that knock down of polycystin-1 or of polycystin-2 inhibited the IP(3)-induced Ca(2+) release. The simultaneous presence of the two polycystins was required to fully amplify the IP(3)-induced Ca(2+) release, since the presence of polycystin-1 alone or of polycystin-2 alone did not result in an increased Ca(2+) release. These novel findings indicate that ER-located polycystin-1 and polycystin-2 operate as a functional complex. They are compatible with the view that loss-of-function mutations in PKD1 and in PKD2 both cause autosomal dominant polycystic kidney disease.
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Affiliation(s)
- D Mekahli
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven Campus Gasthuisberg O&N I, Belgium
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29
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Moktar A, Singh R, Vadhanam MV, Ravoori S, Lillard JW, Gairola CG, Gupta RC. Cigarette smoke condensate-induced oxidative DNA damage and its removal in human cervical cancer cells. Int J Oncol 2011; 39:941-7. [PMID: 21720711 PMCID: PMC3760590 DOI: 10.3892/ijo.2011.1106] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 05/23/2011] [Indexed: 01/03/2023] Open
Abstract
Exposure to cigarette smoke is well documented to increase oxidative stress and could account for higher risk of cervical cancer in smokers. Cervical pre-cancerous lesions that are initiated by human papillomavirus (HPV) infection generally regress in the absence of known risk factors such as smoking. 8-oxodeoxyguanosine (8-oxodG) is a highly mutagenic oxidative DNA lesion that is formed by the oxidation of deoxyguanosine. In the present study, we examined: a) the effect of cigarette smoke condensate (CSC) on 8-oxodG formation in and its removal from HPV-transfected (ECT1/E6 E7), HPV-positive (CaSki) and HPV-negative (C33A) human cervical cancer cells, and b) the cell cycle progression and apoptosis in CSC-treated ECT1/E6 E7 cells. CSC induced 8-oxodG in a dose- (p=0.03) and time (p=0.002)-dependent fashion in ECT1/E6 E7 cells as determined by flow cytometry. A 2.4-fold higher level of 8-oxodG was observed in HPV-positive compared with HPV-negative cells. However, 8-oxodG lesions were almost completely removed 72 h post-exposure in all cell lines as determined by ImageStream analysis. This observation correlates with the 2- and 5-fold increase in the p53 levels in ECT1/E6 E7 and CaSki cells with no significant change in C33A cells. We conclude that: a) cigarette smoke constituents induce oxidative stress with higher burden in HPV-positive cervical cancer cells and b) the significant increase observed in p53 levels in wild-type cervical cells (ECT1/E6 E7 and CaSki) may be attributed to the p53-dependent DNA repair pathway while a p53-independent pathway in C33A cells cannot be ruled out.
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Affiliation(s)
- Afsoon Moktar
- Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40202 , USA
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30
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Generation of the oxidized form protects human brain type creatine kinase against cystine-induced inactivation. Int J Biol Macromol 2011; 48:239-42. [DOI: 10.1016/j.ijbiomac.2010.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 09/26/2010] [Accepted: 09/27/2010] [Indexed: 11/19/2022]
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31
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Novel techniques and newer markers for the evaluation of “proximal tubular dysfunction”. Int Urol Nephrol 2011; 43:1107-15. [DOI: 10.1007/s11255-011-9914-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2010] [Accepted: 02/07/2011] [Indexed: 10/18/2022]
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32
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Wilmer MJ, Kluijtmans LAJ, van der Velden TJ, Willems PH, Scheffer PG, Masereeuw R, Monnens LA, van den Heuvel LP, Levtchenko EN. Cysteamine restores glutathione redox status in cultured cystinotic proximal tubular epithelial cells. Biochim Biophys Acta Mol Basis Dis 2011; 1812:643-51. [PMID: 21371554 DOI: 10.1016/j.bbadis.2011.02.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Revised: 01/28/2011] [Accepted: 02/22/2011] [Indexed: 11/28/2022]
Abstract
Recent evidence implies that impaired metabolism of glutathione has a role in the pathogenesis of nephropathic cystinosis. This recessive inherited disorder is characterized by lysosomal cystine accumulation and results in renal Fanconi syndrome progressing to end stage renal disease in the majority of patients. The most common treatment involves intracellular cystine depletion by cysteamine, delaying the development of end stage renal disease by a yet elusive mechanism. However, cystine depletion does not arrest the disease nor cures Fanconi syndrome in patients, indicating involvement of other yet unknown pathologic pathways. Using a newly developed proximal tubular epithelial cell model from cystinotic patients, we investigate the effect of cystine accumulation and cysteamine on both glutathione and ATP metabolism. In addition to the expected increase in cystine and defective sodium-dependent phosphate reabsorption, we observed less negative glutathione redox status and decreased intracellular ATP levels. No differences between control and cystinosis cell lines were observed with respect to protein turnover, albumin uptake, cytosolic and mitochondrial ATP production, total glutathione levels, protein oxidation and lipid peroxidation. Cysteamine treatment increased total glutathione in both control and cystinotic cells and normalized cystine levels and glutathione redox status in cystinotic cells. However, cysteamine did not improve decreased sodium-dependent phosphate uptake. Our data implicate that cysteamine increases total glutathione and restores glutathione redox status in cystinosis, which is a positive side-effect of this agent next to cystine depletion. This beneficial effect points to a potential role of cysteamine as anti-oxidant for other renal disorders associated with enhanced oxidative stress.
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Affiliation(s)
- Martijn J Wilmer
- Laboratory of Genetic Endocrine and Metabolic Diseases, Department of Laboratory Medicine, Radboud University Nijmegen Medical Centre, The Netherlands
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Sansanwal P, Li L, Hsieh SC, Sarwal MM. Insights into novel cellular injury mechanisms by gene expression profiling in nephropathic cystinosis. J Inherit Metab Dis 2010; 33:775-86. [PMID: 20865335 DOI: 10.1007/s10545-010-9203-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/18/2010] [Accepted: 08/24/2010] [Indexed: 01/27/2023]
Abstract
Nephropathic cystinosis is a rare, inherited metabolic disease caused by functional defects of cystinosin associated with mutations in the CTNS gene. The mechanisms underlying the phenotypic alterations associated with this disease are not well known. In this study, gene expression profiles in peripheral blood of nephropathic cystinosis patients (N = 7) were compared with controls (N = 7) using microarray technology. In unsupervised hierarchical clustering analysis, cystinosis samples co-clustered, and 1,604 genes were significantly differentially expressed between both groups. Gene ontology analysis revealed that differentially expressed genes in cystinosis were enriched in cell organelles such as mitochondria, lysosomes, and endoplasmic reticulum (p ≤ 0.030). The majority of the differentially regulated genes were involved in oxidative phosphorylation, apoptosis, mitochondrial dysfunction, endoplasmic reticulum stress, antigen processing and presentation, B-cell-receptor signaling, and oxidative stress (p ≤ 0.003). Validation of selected genes involved in apoptosis and oxidative phosphorylation was performed by quantitative real-time polymerase chain reaction (PCR). Electron microscopy and confocal imaging of cystinotic renal proximal tubular epithelial cells further confirmed anomalies in the cellular organelles and pathways identified by microarray analysis. Further analysis of these genes and pathways may offer critical insights into the clinical spectrum of cystinosis patients and ultimately lead to novel links for targeted therapy.
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Affiliation(s)
- Poonam Sansanwal
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA, USA.
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34
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Larsen CP, Walker PD, Thoene JG. The incidence of atubular glomeruli in nephropathic cystinosis renal biopsies. Mol Genet Metab 2010; 101:417-20. [PMID: 20826102 DOI: 10.1016/j.ymgme.2010.08.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Revised: 08/16/2010] [Accepted: 08/16/2010] [Indexed: 01/24/2023]
Abstract
Nephropathic cystinosis results from lysosomal cystine storage and, if untreated with cysteamine, results in end-stage renal disease by 10 years of age. The renal Fanconi syndrome occurs in the first year of life and is accompanied by a characteristic "swan neck" deformity of the proximal renal tubule. The linkage between cystine storage, Fanconi syndrome, and renal failure has not been understood. This study reports the presence of substantial numbers of atubular glomeruli (ATG) in end-stage cystinotic renal tissue. Compared to normal renal tissue, cystinotic kidneys at end stage had 69% atubular glomeruli and 30% atrophic glomeruli. Normal renal tissue had 4% ATG and 0% atrophic glomeruli (p<0.0001 for both comparisons). These nonfunctioning nephrons may be the end result of cell loss from the tubules and represent the final stage of the swan neck deformity. The process is consistent with the previously reported increased apoptosis in renal tubule cells due to lysosomal cystine storage.
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35
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Wilmer MJ, Emma F, Levtchenko EN. The pathogenesis of cystinosis: mechanisms beyond cystine accumulation. Am J Physiol Renal Physiol 2010; 299:F905-16. [PMID: 20826575 DOI: 10.1152/ajprenal.00318.2010] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal proximal tubules are highly sensitive to ischemic and toxic insults and are affected in diverse genetic disorders, of which nephropathic cystinosis is the most common. The disease is caused by mutations in the CTNS gene, encoding the lysosomal cystine transporter cystinosin, and is characterized by accumulation of cystine in the lysosomes throughout the body. In the majority of the patients, this leads to generalized proximal tubular dysfunction (also called DeToni-Debré-Fanconi syndrome) in the first year and progressive renal failure during the first decade. Extrarenal organs are affected by cystinosis as well, with clinical symptoms manifesting mostly after 10 yr of age. The cystine-depleting agent cysteamine significantly improves life expectancy of patients with cystinosis, but offers no cure, pointing to the complexity of the disease mechanism. In this review, current knowledge on the pathogenesis of cystinosis is described and placed in perspective of future research.
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Affiliation(s)
- Martijn J Wilmer
- Dept. of Pediatric Nephrology, Univ. Hospitals Leuven, Herestraat 49, 3000 Leuven, Belgium
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36
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Vitvitsky V, Witcher M, Banerjee R, Thoene J. The redox status of cystinotic fibroblasts. Mol Genet Metab 2010; 99:384-8. [PMID: 20061170 PMCID: PMC2839033 DOI: 10.1016/j.ymgme.2009.12.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 12/15/2009] [Indexed: 01/12/2023]
Abstract
A key unresolved question in the pathogenesis of phenotype development in nephropathic cystinosis is whether intralysosomal cystine, the hallmark of this lethal inborn error of metabolism, alters cytoplasmic redox potential. Variable findings on this issue have been reported. This study of fetal and non-fetal skin and lung-derived cystinotic fibroblasts compared to origin and age-matched normal control fibroblasts reveals that cystinotic cells do not exhibit redox perturbations. We find that the steady-state redox status as assessed by the [GSH]/[GSSG] ratio, an indicator of the intracellular redox poise, is unchanged in cystinotic cells. Furthermore, the dependence of the intracellular GSH and cysteine pool sizes and the [GSH]/[GSSG] ratio are similarly dependent on the two major sources of cysteine, i.e. the transsulfuration pathway and the plasma membrane cystine transporter, xc(-), in both cystinotic and control cells, and the presence of lysosomal cystine has no measurable effect on the redox status of these cells. Hence, mechanisms other than cytosolic redox perturbations are involved in the etiology of nephropathic cystinosis.
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Affiliation(s)
- Victor Vitvitsky
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, MI 48109-5606
| | - Marc Witcher
- Department of Pediatric Genetics, University of Michigan Medical Center, Ann Arbor, MI 48109-5606
| | - Ruma Banerjee
- Department of Biological Chemistry, University of Michigan Medical Center, Ann Arbor, MI 48109-5606
| | - Jess Thoene
- Department of Pediatric Genetics, University of Michigan Medical Center, Ann Arbor, MI 48109-5606
- Corresponding Author: Phone: 734-763-3427,
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Wallace DC, Fan W, Procaccio V. Mitochondrial energetics and therapeutics. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2010; 5:297-348. [PMID: 20078222 DOI: 10.1146/annurev.pathol.4.110807.092314] [Citation(s) in RCA: 496] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mitochondrial dysfunction has been linked to a wide range of degenerative and metabolic diseases, cancer, and aging. All these clinical manifestations arise from the central role of bioenergetics in cell biology. Although genetic therapies are maturing as the rules of bioenergetic genetics are clarified, metabolic therapies have been ineffectual. This failure results from our limited appreciation of the role of bioenergetics as the interface between the environment and the cell. A systems approach, which, ironically, was first successfully applied over 80 years ago with the introduction of the ketogenic diet, is required. Analysis of the many ways that a shift from carbohydrate glycolytic metabolism to fatty acid and ketone oxidative metabolism may modulate metabolism, signal transduction pathways, and the epigenome gives us an appreciation of the ketogenic diet and the potential for bioenergetic therapeutics.
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Affiliation(s)
- Douglas C Wallace
- Center for Molecular and Mitochondrial Medicine and Genetics and Departments of Biological Chemistry, Ecology and Evolutionary Biology, and Pediatrics, University of California at Irvine, Irvine, California 92697-3940, USA.
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Taranta A, Wilmer MJ, van den Heuvel LP, Bencivenga P, Bellomo F, Levtchenko EN, Emma F. Analysis of CTNS gene transcripts in nephropathic cystinosis. Pediatr Nephrol 2010; 25:1263-7. [PMID: 20352457 PMCID: PMC2874020 DOI: 10.1007/s00467-010-1502-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 02/23/2010] [Accepted: 03/01/2010] [Indexed: 11/30/2022]
Abstract
Nephropathic cystinosis (NC) is an autosomal recessive disorder caused by mutations of the CTNS gene that encodes for a cystine transmembrane transporter. Several mutations have been described in the coding and promoter regions of the CTNS gene in affected individuals. We selected three patients with NC from two unrelated families, in whom sequence analysis of the CTNS gene detected only one or no mutations. Total RNA was isolated from peripheral blood mononuclear cells or fibroblasts and CTNS transcripts were analyzed. We observed a skipping of exon 5 (85 bp) in two siblings and an intron 9 retention of 75 bp associated with partial replication of exon 9 in the third patient. Genomic DNA analysis of intron regions surrounding exon 5 showed a point mutation in the hypothetical lariat branch site of intron 4 at position -24 (c.141-24 T > C) in the first two patients and a duplication of 266 bp including a part of exon and intron 9 in the third patient. Analysis of CTNS gene transcripts allowed identification of mutations in patients in whom CTNS mutations could not be detected by traditional DNA sequencing. These results support the hypothesis that cystinosis is a monogenic disorder.
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Affiliation(s)
- Anna Taranta
- Department of Nephrology and Urology, Division of Nephrology, Bambino Gesù Children's Hospital and Research Institute, Piazza S. Onofrio, 4, 00165, Rome, Italy.
| | - Martijn J. Wilmer
- Laboratory of Pediatrics and Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Lambert P. van den Heuvel
- Laboratory of Pediatrics and Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands ,Department of Pediatrics/Pediatric Nephrology, University Hospital Gasthuisberg, Leuven, Belgium
| | - Paola Bencivenga
- Laboratory of Scientific Research, Bambino Gesù Children’s Hospital and Research Institute, Rome, Italy
| | - Francesco Bellomo
- Department of Nephrology and Urology, Division of Nephrology, Bambino Gesù Children’s Hospital and Research Institute, Piazza S. Onofrio, 4, 00165 Rome, Italy
| | - Elena N. Levtchenko
- Department of Pediatrics/Pediatric Nephrology, University Hospital Gasthuisberg, Leuven, Belgium
| | - Francesco Emma
- Department of Nephrology and Urology, Division of Nephrology, Bambino Gesù Children’s Hospital and Research Institute, Piazza S. Onofrio, 4, 00165 Rome, Italy
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Figueiredo VC, Feksa LR, Wannmacher CMD. Cysteamine prevents inhibition of adenylate kinase caused by cystine in rat brain cortex. Metab Brain Dis 2009; 24:723-31. [PMID: 19437111 DOI: 10.1007/s11011-009-9141-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 04/14/2009] [Indexed: 10/20/2022]
Abstract
Cystinosis is a systemic genetic disease caused by a lysosomal transport deficiency accumulating cystine in the lysosomes of almost all tissues. Although tissue damage might depend on cystine accumulation, the mechanisms of tissue damage are still obscures. Adenylate kinase, along with creatine kinase, is responsible for the enzymatic phosphotransfer network, crucial for energy homeostasis. Taking into account that cystine is known to inhibit creatine kinase activity, the two enzymes have thiol groups, and the strong interaction between the two activities, our main objective was to investigate the effect of cystine on adenylate kinase activity in the brain cortex of Wistar rats. For the in vivo studies, the animals were injected twice a day with 1.6 micromol/g body weight of cystine dimethylester and/or 0.46 micromol/g body weight of cysteamine from the 25th to the 29th postpartum day and sacrificed after 12 h. Cystine inhibited the enzyme activity in vitro in a concentration dependent way, whereas cysteamine prevented the inhibition. Adenylate kinase activity was found diminished in the brain cortex of rats loaded with cystine dimethylester and co-administration of cysteamine prevented the diminution of the enzyme activity. Considering that adenylate kinase together with creatine kinase is crucial for energy homeostasis, the release of cystine from lysosomes with consequent enzymes inhibition could impair energy homeostasis, contributing to tissue damage in patients with cystinosis.
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Affiliation(s)
- Vandré Casagrande Figueiredo
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Rua Ramiro Barcelos 2600, Porto Alegre, RS, CEP 90.035-003, Brazil
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40
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Novel conditionally immortalized human proximal tubule cell line expressing functional influx and efflux transporters. Cell Tissue Res 2009; 339:449-57. [PMID: 19902259 PMCID: PMC2817082 DOI: 10.1007/s00441-009-0882-y] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 09/09/2009] [Indexed: 12/16/2022]
Abstract
Reabsorption of filtered solutes from the glomerular filtrate and excretion of waste products and xenobiotics are the main functions of the renal proximal tubular (PT) epithelium. A human PT cell line expressing a range of functional transporters would help to augment current knowledge in renal physiology and pharmacology. We have established and characterized a conditionally immortalized PT epithelial cell line (ciPTEC) obtained by transfecting and subcloning cells exfoliated in the urine of a healthy volunteer. The PT origin of this line has been confirmed morphologically and by the expression of aminopeptidase N, zona occludens 1, aquaporin 1, dipeptidyl peptidase IV and multidrug resistance protein 4 together with alkaline phosphatase activity. ciPTEC assembles in a tight monolayer with limited diffusion of inulin-fluorescein-isothiocyanate. Concentration and time-dependent reabsorption of albumin via endocytosis has been demonstrated, together with sodium-dependent phosphate uptake. The expression and activity of apical efflux transporter p-glycoprotein and of baso-lateral influx transporter organic cation transporter 2 have been shown in ciPTEC. This established human ciPTEC expressing multiple endogenous organic ion transporters mimicking renal reabsorption and excretion represents a powerful tool for future in vitro transport studies in pharmacology and physiology.
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41
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Cairo ER, Swarts HGP, Wilmer MJG, Willems PHGM, Levtchenko EN, De Pont JJHHM, Koenderink JB. FXYD2 and Na,K-ATPase expression in isolated human proximal tubular cells: disturbed upregulation on renal hypomagnesemia? J Membr Biol 2009; 231:117-24. [PMID: 19865785 PMCID: PMC2776943 DOI: 10.1007/s00232-009-9210-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 10/08/2009] [Indexed: 11/05/2022]
Abstract
Autosomal dominant renal hypomagnesemia (OMIM 154020), associated with hypocalciuria, has been linked to a 121G to A mutation in the FXYD2 gene. To gain insight into the molecular mechanisms linking this mutation to the clinical phenotype, we studied isolated proximal tubular cells from urine of a patient and a healthy subject. Cells were immortalized and used to assess the effects of hypertonicity-induced overexpression of FXYD2 on amount, activity and apparent affinities for Na+, K+ and ATP of Na,K-ATPase. Both cell lines expressed mRNA for FXYD2a and FXYD2b, and patient cells contained both the wild-type and mutated codons. FXYD2 protein expression was lower in patient cells and could be increased in both cell lines upon culturing in hyperosmotic medium but to a lesser extent in patient cells. Similarly, hyperosmotic culturing increased Na,K-ATPase protein expression and ATP hydrolyzing activity but, again, to a lesser extent in patient cells. Apparent affinities of Na,K-ATPase for Na+, K+ and ATP did not differ between patient and control cells or after hyperosmotic induction. We conclude that human proximal tubular cells respond to a hyperosmotic challenge with an increase in FXYD2 and Na,K-ATPase protein expression, though to a smaller absolute extent in patient cells.
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Affiliation(s)
- Edinio R Cairo
- Department of Biochemistry, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands
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42
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Figueiredo VC, Feksa LR, Wannmacher CMD. Cysteamine prevents inhibition of adenylate kinase caused by cystine in rat brain cortex. Metab Brain Dis 2009; 24:373-81. [PMID: 19688256 DOI: 10.1007/s11011-009-9142-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 04/09/2009] [Indexed: 10/20/2022]
Abstract
Cystinosis is a systemic genetic disease caused by a lysosomal transport deficiency accumulating cystine in the lysosomes of almost all tissues. Although tissue damage might depend on cystine accumulation, the mechanisms of tissue damage are still obscures. Adenylate kinase, along with creatine kinase, is responsible for the enzymatic phosphotransfer network, crucial for energy homeostasis. Taking into account that cystine is known to inhibit creatine kinase activity, the two enzymes have thiol groups, and the strong interaction between the two activities, our main objective was to investigate the effect of cystine on adenylate kinase activity in the brain cortex of Wistar rats. For the in vivo studies, the animals were injected twice a day with 1.6 micromol/g body weight of cystine dimethylester and/or 0.46 micromol/g body weight of cysteamine from the 25th to the 29th postpartum day and sacrificed after 12 h. Cystine inhibited the enzyme activity in vitro in a concentration dependent way, whereas cysteamine prevented the inhibition. Adenylate kinase activity was found diminished in the brain cortex of rats loaded with cystine dimethylester and co-administration of cysteamine prevented the diminution of the enzyme activity. Considering that adenylate kinase together with creatine kinase is crucial for energy homeostasis, the release of cystine from lysosomes with consequent enzymes inhibition could impair energy homeostasis, contributing to tissue damage in patients with cystinosis.
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Affiliation(s)
- Vandré Casagrande Figueiredo
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600, CEP 90.035-003, Porto Alegre, RS, Brazil
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43
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Yuan ZX, Zhang ZR, Zhu D, Sun X, Gong T, Liu J, Luan CT. Specific Renal Uptake of Randomly 50% N-Acetylated Low Molecular Weight Chitosan. Mol Pharm 2008; 6:305-14. [PMID: 19035784 DOI: 10.1021/mp800078a] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhi-xiang Yuan
- Key Laboratory of Drug Targeting and Drug Delivery Systems, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Zhi-rong Zhang
- Key Laboratory of Drug Targeting and Drug Delivery Systems, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Di Zhu
- Key Laboratory of Drug Targeting and Drug Delivery Systems, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Xun Sun
- Key Laboratory of Drug Targeting and Drug Delivery Systems, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Tao Gong
- Key Laboratory of Drug Targeting and Drug Delivery Systems, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Jie Liu
- Key Laboratory of Drug Targeting and Drug Delivery Systems, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China
| | - Chang-tao Luan
- Key Laboratory of Drug Targeting and Drug Delivery Systems, Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, People’s Republic of China
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44
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Wilmer MJ, van den Heuvel LP, Rodenburg RJ, Vogel RO, Nijtmans LG, Monnens LA, Levtchenko EN. Mitochondrial complex V expression and activity in cystinotic fibroblasts. Pediatr Res 2008; 64:495-7. [PMID: 18596576 DOI: 10.1203/pdr.0b013e318183fd67] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Alterations in ATP metabolism have been proposed to be involved in the pathogenesis of cystinosis, the most common form of inherited Fanconi syndrome. A recent study showed normal activity of respiratory chain complexes I-IV with decreased ATP levels in cystinotic fibroblasts. Here, we show normal complex V expression and activity in mitochondria of cystinotic fibroblasts. This indicates that alterations in mitochondrial oxidative phosphorylation enzymes are not responsible for ATP decrease in cystinotic fibroblasts.
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Affiliation(s)
- Martijn J Wilmer
- Laboratory of Pediatrics and Neurology, Radboud University Nijmegen Medical Centre, Nijmegen, 6500 HB, The Netherlands.
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45
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46
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Rech VC, Feksa LR, Fleck RMM, Athaydes GA, Dornelles PKB, Rodrigues-Junior V, Wannmacher CMD. Cysteamine prevents inhibition of thiol-containing enzymes caused by cystine or cystine dimethylester loading in rat brain cortex. Metab Brain Dis 2008; 23:133-45. [PMID: 18418703 DOI: 10.1007/s11011-008-9081-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2007] [Accepted: 12/10/2007] [Indexed: 12/18/2022]
Abstract
Cystinosis is a systemic genetic disease caused by a lysosomal transport deficiency accumulating cystine in the lysosomes of all tissues. Although tissue damage might depend on cystine accumulation, the mechanisms of tissue damage are still obscures. Considering that thiol-containing enzymes are critical for several metabolic pathways, our main objective was to investigate the effects of cystine or cystine dimethylester load on the thiol-containing enzymes creatine kinase and pyruvate kinase, in the brain cortex of young Wistar rats. The animals were injected twice a day with 1.6 micromol/g body weight of cystine dimethylester or 1 micromol/g body weight of cystine and/or 0.46 micromol/g body weight of cysteamine from the 16th to the 20th postpartum day and sacrificed after 12 h. Cystine or cystine dimethylester administration inhibited the two enzyme activities. Co-administration of cysteamine, the drug used to treat cystinotic patients, normalized the two enzyme activities. Lactate dehydrogenase activity, a nonthiol-containing enzyme was not affected by cystine dimethylester administration. Cystine inhibits creatine kinase and pyruvate activities possibly by oxidation of the sulfhydryl groups of the enzymes. Considering that creatine kinase and pyruvate kinase, like other thiol-containing enzymes, are crucial for energy homeostasis and antioxidant defenses, the enzymes inhibition caused by cystine released from lysosomes could be one of the mechanisms of tissue damage in patients with cystinosis.
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Affiliation(s)
- Virginia Cielo Rech
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Rua Ramiro Barcelos 2600, CEP 90.035-003, Porto Alegre, Rio Grande do Sul, Brazil
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47
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Bens M, Vandewalle A. Cell models for studying renal physiology. Pflugers Arch 2008; 457:1-15. [DOI: 10.1007/s00424-008-0507-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Accepted: 03/22/2008] [Indexed: 12/24/2022]
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48
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Wilmer MJ, van den Heuvel LP, Levtchenko EN. The use of CDME in cystinosis research. Neurochem Res 2008; 33:2373-4. [PMID: 18427982 DOI: 10.1007/s11064-008-9709-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Accepted: 04/03/2008] [Indexed: 12/21/2022]
Affiliation(s)
- Martijn J Wilmer
- Laboratory of Pediatrics and Neurology (656), Radboud University Nijmegen Medical Centre, P.O. 9101, 6500 HB, Nijmegen, The Netherlands.
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49
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A novel renal carbonic anhydrase type III plays a role in proximal tubule dysfunction. Kidney Int 2008; 74:52-61. [PMID: 18322545 DOI: 10.1038/sj.ki.5002794] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Dysfunction of the proximal tubule (PT) is associated with variable degrees of solute wasting and low-molecular-weight proteinuria. We measured metabolic consequences and adaptation mechanisms in a model of inherited PT disorders using PT cells of ClC-5-deficient (Clcn5Y/-) mice, a well-established model of Dent's disease. Compared to cells taken from control mice, those from the mutant mice had increased expression of markers of proliferation (Ki67, proliferative cell nuclear antigen (PCNA), and cyclin E) and oxidative scavengers (superoxide dismutase I and thioredoxin). Transcriptome and protein analyses showed fourfold induction of type III carbonic anhydrase in a kidney-specific manner in the knockout mice located in scattered PT cells. Kidney-specific carbonic anhydrase type III (CAIII) upregulation was confirmed in other mice lacking the multiligand receptor megalin and in a patient with Dent's disease due to an inactivating CLCN5 mutation. The type III enzyme was specifically detected in the urine of mice lacking ClC-5 or megalin, patients with Dent's disease, and in PT cell lines exposed to oxidative stress. Our study shows that lack of PT ClC-5 in mice and men is associated with CAIII induction, increased cell proliferation, and oxidative stress.
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50
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Huls M, Brown C, Windass A, Sayer R, van den Heuvel J, Heemskerk S, Russel F, Masereeuw R. The breast cancer resistance protein transporter ABCG2 is expressed in the human kidney proximal tubule apical membrane. Kidney Int 2008; 73:220-5. [DOI: 10.1038/sj.ki.5002645] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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