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Christer S, Simons M. Lysosomal cystine accumulation activates mTOR signaling in cystinosis: are mTOR inhibitors the cure? Kidney Int 2024; 105:656-658. [PMID: 38519228 DOI: 10.1016/j.kint.2023.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/01/2023] [Indexed: 03/24/2024]
Affiliation(s)
- Salómon Christer
- Nephrogenetics Unit, Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany
| | - Matias Simons
- Nephrogenetics Unit, Institute of Human Genetics, University Hospital Heidelberg, Heidelberg, Germany.
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2
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Rega LR, Janssens V, Graversen JH, Moestrup SK, Cairoli S, Goffredo BM, Nevo N, Courtoy GE, Jouret F, Antignac C, Emma F, Pierreux CE, Courtoy PJ. Dietary supplementation of cystinotic mice by lysine inhibits the megalin pathway and decreases kidney cystine content. Sci Rep 2023; 13:17276. [PMID: 37828038 PMCID: PMC10570359 DOI: 10.1038/s41598-023-43105-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 09/20/2023] [Indexed: 10/14/2023] Open
Abstract
Megalin/LRP2 is a major receptor supporting apical endocytosis in kidney proximal tubular cells. We have previously reported that kidney-specific perinatal ablation of the megalin gene in cystinotic mice, a model of nephropathic cystinosis, essentially blocks renal cystine accumulation and partially preserves kidney tissue integrity. Here, we examined whether inhibition of the megalin pathway in adult cystinotic mice by dietary supplementation (5x-fold vs control regular diet) with the dibasic amino-acids (dAAs), lysine or arginine, both of which are used to treat patients with other rare metabolic disorders, could also decrease renal cystine accumulation and protect cystinotic kidneys. Using surface plasmon resonance, we first showed that both dAAs compete for protein ligand binding to immobilized megalin in a concentration-dependent manner, with identical inhibition curves by L- and D-stereoisomers. In cystinotic mice, 2-month diets with 5x-L-lysine and 5x-L-arginine were overall well tolerated, while 5x-D-lysine induced strong polyuria but no weight loss. All diets induced a marked increase of dAA urinary excretion, most prominent under 5x-D-lysine, without sign of kidney insufficiency. Renal cystine accumulation was slowed down approx. twofold by L-dAAs, and totally suppressed by D-lysine. We conclude that prolonged dietary manipulation of the megalin pathway in kidneys is feasible, tolerable and can be effective in vivo.
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Affiliation(s)
- L R Rega
- Nephrology Research Unit, Translational Pediatrics and Clinical Genetics Research Area, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - V Janssens
- Cell Biology Unit, de Duve Institute and Louvain University Medical School, Brussels, Belgium
| | - J H Graversen
- Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - S K Moestrup
- Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - S Cairoli
- Division of Metabolic Diseases and Drug Biology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - B M Goffredo
- Division of Metabolic Diseases and Drug Biology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - N Nevo
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Institut Imagine, Université Paris Cité, Paris, France
| | - G E Courtoy
- Imaging Platform (2IP), Institut de Recherche Expérimentale et Clinique, Louvain University Medical School, Brussels, Belgium
| | - F Jouret
- Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA), Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - C Antignac
- Laboratoire des Maladies Rénales Héréditaires, Inserm UMR 1163, Institut Imagine, Université Paris Cité, Paris, France
| | - F Emma
- Nephrology Research Unit, Translational Pediatrics and Clinical Genetics Research Area, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - C E Pierreux
- Cell Biology Unit, de Duve Institute and Louvain University Medical School, Brussels, Belgium.
| | - P J Courtoy
- Cell Biology Unit, de Duve Institute and Louvain University Medical School, Brussels, Belgium.
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3
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Chen M, Gu X. Emerging roles of proximal tubular endocytosis in renal fibrosis. Front Cell Dev Biol 2023; 11:1235716. [PMID: 37799275 PMCID: PMC10547866 DOI: 10.3389/fcell.2023.1235716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/11/2023] [Indexed: 10/07/2023] Open
Abstract
Endocytosis is a crucial component of many pathological conditions. The proximal tubules are responsible for reabsorbing the majority of filtered water and glucose, as well as all the proteins filtered through the glomerular barrier via endocytosis, indicating an essential role in kidney diseases. Genetic mutations or acquired insults could affect the proximal tubule endocytosis processes, by disturbing or overstressing the endolysosomal system and subsequently activating different pathways, orchestrating renal fibrosis. This paper will review recent studies on proximal tubular endocytosis affected by other diseases and factors. Endocytosis plays a vital role in the development of renal fibrosis, and renal fibrosis could also, in turn, affect tubular endocytosis.
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Affiliation(s)
- Min Chen
- Department of Nephrology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Xiangchen Gu
- Department of Nephrology, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- Department of Nephrology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Medicine, Shanghai Hospital of Civil Aviation Administration of China, Shanghai, China
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4
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Elsakka EGE, Mokhtar MM, Hegazy M, Ismail A, Doghish AS. Megalin, a multi-ligand endocytic receptor, and its participation in renal function and diseases: A review. Life Sci 2022; 308:120923. [PMID: 36049529 DOI: 10.1016/j.lfs.2022.120923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/13/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022]
Abstract
The endocytosis mechanism is a complicated system that is essential for cell signaling and survival. Megalin, a membrane-associated endocytic receptor, and its related proteins such as cubilin, the neonatal Fc receptor for IgG, and NaPi-IIa are important in receptors-mediated endocytosis. Physiologically, megalin uptakes plasma vitamins and proteins from primary urine, preventing their loss. It also facilitates tubular retrieval of solutes and endogenous components that may be involved in modulation and recovery from kidney injuries. Moreover, megalin is responsible for endocytosis of xenobiotics and drugs in renal tubules, increasing their half-life and/or their toxicity. Fluctuations in megalin expression and/or functionality due to changes in its regulatory mechanisms are associated with some sort of kidney injury. Also, it's an important component of several pathological conditions, including diabetic nephropathy and Dent disease. Thus, exploring the fundamental role of megalin in the kidney might help in the protection and/or treatment of multiple kidney-related diseases. Hence, this review aimed to explore the physiological roles of megalin in the kidney and their implications for kidney-related injuries.
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Affiliation(s)
- Elsayed G E Elsakka
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt.
| | - Mahmoud Mohamed Mokhtar
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Maghawry Hegazy
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Ahmed Ismail
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Ahmed S Doghish
- Department of Biochemistry, Faculty of Pharmacy, Badr University in Cairo (BUC), Badr City, Cairo 11829, Egypt.
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5
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Hollywood JA, Kallingappa PK, Cheung PY, Martis RM, Sreebhavan S, 'Atiola RD, Chatterjee A, Buckels EJ, Matthews BG, Lewis PM, Davidson AJ. Cystinosin deficient rats recapitulate the phenotype of nephropathic cystinosis. Am J Physiol Renal Physiol 2022; 323:F156-F170. [PMID: 35695380 DOI: 10.1152/ajprenal.00277.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The lysosomal storage disease cystinosis is caused by mutations in CTNS, encoding a cystine transporter, and in its severest form leads to proximal tubule dysfunction followed by kidney failure. Patients receive the drug-based therapy cysteamine from diagnosis. However, despite long-term treatment, cysteamine only slows the progression of end-stage renal disease. Pre-clinical testing in cystinotic rodents is required to evaluate new therapies; however, the current models are sub-optimal. To solve this problem we generated a new cystinotic rat model using CRISPR/Cas9-mediated gene editing to disrupt exon 3 of Ctns and measured various parameters over a 12-month time-course. Ctns-/- rats display hallmarks of cystinosis by 3-6 months of age as seen by a failure to thrive, excessive thirst and urination, cystine accumulation in tissues, corneal cystine crystals, a loss of Lrp2 in proximal tubules and immune cell infiltration. High levels of glucose, calcium, albumin and protein are excreted at 6-months of age, consistent with the onset of Fanconi syndrome, with a progressive diminution of urine urea and creatinine from 9-months of age, indicative of chronic kidney disease. The kidney histology and immunohistochemistry showed proximal tubule atrophy and glomerular damage as well as classic 'swan neck' lesions. Overall, Ctns-/- rats show a disease progression that more faithfully recapitulates nephropathic cystinosis than existing rodent models. The Ctns-/- rat provides an excellent new rodent model of nephropathic cystinosis that is ideally suited for conducting pre-clinical drug testing and a powerful tool to advance cystinosis research.
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Affiliation(s)
- Jennifer Anne Hollywood
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Prasanna Kumar Kallingappa
- Faculty of Medical and Health Sciences, Vernon Jansen Unit, The University of Auckland, Auckland, New Zealand
| | - Pang Yuk Cheung
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Renita M Martis
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Sree Sreebhavan
- Auckland Cancer Society Research Centre, The University of Auckland, Auckland, New Zealand
| | - Robert Douglas 'Atiola
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Aparajita Chatterjee
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Emma Jane Buckels
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Brya G Matthews
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Paula M Lewis
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
| | - Alan J Davidson
- Department of Molecular Medicine and Pathology, The University of Auckland, Auckland, New Zealand
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6
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Long KR, Rbaibi Y, Bondi CD, Ford BR, Poholek AC, Boyd-Shiwarski CR, Tan RJ, Locker JD, Weisz OA. Cubilin-, megalin-, and Dab2-dependent transcription revealed by CRISPR/Cas9 knockout in kidney proximal tubule cells. Am J Physiol Renal Physiol 2022; 322:F14-F26. [PMID: 34747197 PMCID: PMC8698540 DOI: 10.1152/ajprenal.00259.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 01/03/2023] Open
Abstract
The multiligand receptors megalin (Lrp2) and cubilin (Cubn) and their endocytic adaptor protein Dab2 (Dab2) play essential roles in maintaining the integrity of the apical endocytic pathway of proximal tubule (PT) cells and have complex and poorly understood roles in the development of chronic kidney disease. Here, we used RNA-sequencing and CRISPR/Cas9 knockout (KO) technology in a well-differentiated cell culture model to identify PT-specific transcriptional changes that are directly consequent to the loss of megalin, cubilin, or Dab2 expression. KO of Lrp2 had the greatest transcriptional effect, and nearly all genes whose expression was affected in Cubn KO and Dab2 KO cells were also changed in Lrp2 KO cells. Pathway analysis and more granular inspection of the altered gene profiles suggested changes in pathways with immunomodulatory functions that might trigger the pathological changes observed in KO mice and patients with Donnai-Barrow syndrome. In addition, differences in transcription patterns between Lrp2 and Dab2 KO cells suggested the possibility that altered spatial signaling by aberrantly localized receptors contributes to transcriptional changes upon the disruption of PT endocytic function. A reduction in transcripts encoding sodium-glucose cotransporter isoform 2 was confirmed in Lrp2 KO mouse kidney lysates by quantitative PCR analysis. Our results highlight the role of megalin as a master regulator and coordinator of ion transport, metabolism, and endocytosis in the PT. Compared with the studies in animal models, this approach provides a means to identify PT-specific transcriptional changes that are directly consequent to the loss of these target genes.NEW & NOTEWORTHY Megalin and cubilin receptors together with their adaptor protein Dab2 represent major components of the endocytic machinery responsible for efficient uptake of filtered proteins by the proximal tubule (PT). Dab2 and megalin expression have been implicated as both positive and negative modulators of kidney disease. We used RNA sequencing to knock out CRISPR/Cas9 cubilin, megalin, and Dab2 in highly differentiated PT cells to identify PT-specific changes that are directly consequent to knockout of each component.
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MESH Headings
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Agenesis of Corpus Callosum/genetics
- Agenesis of Corpus Callosum/metabolism
- Agenesis of Corpus Callosum/pathology
- Animals
- Apoptosis Regulatory Proteins/genetics
- Apoptosis Regulatory Proteins/metabolism
- CRISPR-Associated Protein 9/genetics
- CRISPR-Cas Systems
- Cells, Cultured
- Databases, Genetic
- Gene Knockout Techniques
- Gene Regulatory Networks
- Hearing Loss, Sensorineural/genetics
- Hearing Loss, Sensorineural/metabolism
- Hearing Loss, Sensorineural/pathology
- Hernias, Diaphragmatic, Congenital/genetics
- Hernias, Diaphragmatic, Congenital/metabolism
- Hernias, Diaphragmatic, Congenital/pathology
- Humans
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/pathology
- Low Density Lipoprotein Receptor-Related Protein-2/genetics
- Low Density Lipoprotein Receptor-Related Protein-2/metabolism
- Male
- Mice, Knockout
- Monodelphis
- Myopia/genetics
- Myopia/metabolism
- Myopia/pathology
- Proteinuria/genetics
- Proteinuria/metabolism
- Proteinuria/pathology
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Renal Tubular Transport, Inborn Errors/genetics
- Renal Tubular Transport, Inborn Errors/metabolism
- Renal Tubular Transport, Inborn Errors/pathology
- Transcription, Genetic
- Mice
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Affiliation(s)
- Kimberly R Long
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Youssef Rbaibi
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Corry D Bondi
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - B Rhodes Ford
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Amanda C Poholek
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Cary R Boyd-Shiwarski
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Roderick J Tan
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Joseph D Locker
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Ora A Weisz
- Renal Electrolyte Division, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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7
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Krohn P, Rega LR, Harvent M, Festa BP, Taranta A, Luciani A, Dewulf J, Cremonesi A, Camassei FD, Hanson JVM, Gerth-Kahlert C, Emma F, Berquez M, Devuyst O. OUP accepted manuscript. Hum Mol Genet 2022; 31:2262-2278. [PMID: 35137071 PMCID: PMC9262394 DOI: 10.1093/hmg/ddac033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/21/2022] [Accepted: 02/02/2022] [Indexed: 11/14/2022] Open
Abstract
Recessive mutations in the CTNS gene encoding the lysosomal transporter cystinosin cause cystinosis, a lysosomal storage disease leading to kidney failure and multisystem manifestations. A Ctns knockout mouse model recapitulates features of cystinosis, but the delayed onset of kidney manifestations, phenotype variability and strain effects limit its use for mechanistic and drug development studies. To provide a better model for cystinosis, we generated a Ctns knockout rat model using CRISPR/Cas9 technology. The Ctns−/− rats display progressive cystine accumulation and crystal formation in multiple tissues including kidney, liver and thyroid. They show an early onset and progressive loss of urinary solutes, indicating generalized proximal tubule dysfunction, with development of typical swan-neck lesions, tubulointerstitial fibrosis and kidney failure, and decreased survival. The Ctns−/− rats also present crystals in the cornea, and bone and liver defects, as observed in patients. Mechanistically, the loss of cystinosin induces a phenotype switch associating abnormal proliferation and dedifferentiation, loss of apical receptors and transporters, and defective lysosomal activity and autophagy in the cells. Primary cultures of proximal tubule cells derived from the Ctns−/− rat kidneys confirmed the key changes caused by cystine overload, including reduced endocytic uptake, increased proliferation and defective lysosomal dynamics and autophagy. The novel Ctns−/− rat model and derived proximal tubule cell system provide invaluable tools to investigate the pathogenesis of cystinosis and to accelerate drug discovery.
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Affiliation(s)
- Patrick Krohn
- Institute of Physiology, University of Zurich, Zurich 8057, Switzerland
| | - Laura Rita Rega
- Renal Diseases Research Unit, Genetics and Rare Diseases Research Area, Bambino Gesù Children’s Hospital, IRCCS, Rome 00165, Italy
| | - Marianne Harvent
- Institute of Physiology, University of Zurich, Zurich 8057, Switzerland
| | | | - Anna Taranta
- Renal Diseases Research Unit, Genetics and Rare Diseases Research Area, Bambino Gesù Children’s Hospital, IRCCS, Rome 00165, Italy
| | | | - Joseph Dewulf
- Department of Laboratory Medicine, Cliniques universitaires Saint Luc, UCLouvain, Brussels 1200, Belgium
- Department of Biochemistry, de Duve Institute, UCLouvain, Brussels 1200, Belgium
| | - Alessio Cremonesi
- Division of Clinical Chemistry and Biochemistry, University Children’s Hospital Zurich, Zurich 8032, Switzerland
| | | | - James V M Hanson
- Department of Ophthalmology, University Hospital Zurich and University of Zurich, Zurich 8091, Switzerland
| | - Christina Gerth-Kahlert
- Department of Ophthalmology, University Hospital Zurich and University of Zurich, Zurich 8091, Switzerland
| | - Francesco Emma
- Renal Diseases Research Unit, Genetics and Rare Diseases Research Area, Bambino Gesù Children’s Hospital, IRCCS, Rome 00165, Italy
- Department of Pediatric Subspecialties, Division of Nephrology, Children’s Hospital Bambino Gesù, IRCCS, Rome 00165, Italy
| | - Marine Berquez
- To whom correspondence should be addressed at: University of Zurich, Mechanisms of Inherited Kidney Disorders Group, Winterthurerstrasse 190, Zurich 8057, Switzerland. Tel: +41 (0)44 635 51 07; (Marine Berquez); Tel: +41 (0)44 635 50 82; Fax: +41 (0)44 635 68 14; (Olivier Devuyst)
| | - Olivier Devuyst
- To whom correspondence should be addressed at: University of Zurich, Mechanisms of Inherited Kidney Disorders Group, Winterthurerstrasse 190, Zurich 8057, Switzerland. Tel: +41 (0)44 635 51 07; (Marine Berquez); Tel: +41 (0)44 635 50 82; Fax: +41 (0)44 635 68 14; (Olivier Devuyst)
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8
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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9
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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