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Dong F, Amlal H, Venkatakrishnan J, Zhang J, Fry M, Yuan Y, Cheng YC, Hu YC, Kao WWY. The gene therapy for corneal pathology with novel nonsense cystinosis mouse lines created by CRISPR Gene Editing. Ocul Surf 2023; 29:432-443. [PMID: 37355021 PMCID: PMC10725217 DOI: 10.1016/j.jtos.2023.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/26/2023] [Accepted: 06/02/2023] [Indexed: 06/26/2023]
Abstract
PURPOSE Cystinosis is an autosomal recessive lysosomal storage disease (LSDs) caused by mutations in the gene encoding cystinosin (CTNS) that leads to cystine crystal accumulation in the lysosome that compromises cellular functions resulting in tissue damage and organ failure, especially in kidneys and eyes. However, the underlying molecular mechanism of its pathogenesis remains elusive. Two novel mice lines created via CRISPR are used to examine the pathogenesis of cystinosis in the kidney and cornea and the treatment efficacy of corneal pathology using self-complimentary Adeno-associated viral (scAAV-CTNS) vector. METHODS The CRISPR technique generated two novel cystinotic mouse lines, Ctnsis1 (an insertional mutation) and Ctnsis2 (a nonsense mutation). Immune histochemistry, renal functions test and HRT2 in vivo confocal microscopy were used to evaluate the age-related renal pathogenesis and treatment efficacy of the scAAV-CTNS virus in corneal pathology. RESULTS Both mutations lead to the production of truncated Ctns proteins. Ctnsis1 and Ctnsis 2 mice exhibit the characteristic of cystinotic corneal crystal phenotype at four-week-old. Treatment with the scAAV-CTNS viral vector decreased the corneal crystals in the treated mice cornea. Ctnsis 1 show renal abnormalities manifested by increased urine volume, reduced urine osmolality, and the loss of response to Desmopressin (dDAVP) at 22-month-old but Ctnsis2 don't manifest renal pathology up to 2 years of age. CONCLUSIONS Both Ctnsis1 and Ctnsis2 mice exhibit phenotypes resembling human intermediate nephropathic and ocular cystinosis, respectively. scAAV-CTNS viral vectors reduce the corneal cystine crystals and have a great potential as a therapeutic strategy for treating patients suffering from cystinosis.
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Affiliation(s)
- Fei Dong
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Hassane Amlal
- Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | | | - Jianhua Zhang
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Matthew Fry
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Yong Yuan
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Yu Chia Cheng
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA
| | - Yueh-Chiang Hu
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Winston W-Y Kao
- Department of Ophthalmology, University of Cincinnati, Cincinnati, OH, USA.
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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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Brasell EJ, Chu LL, Akpa MM, Eshkar-Oren I, Alroy I, Corsini R, Gilfix BM, Yamanaka Y, Huertas P, Goodyer P. The novel aminoglycoside, ELX-02, permits CTNSW138X translational read-through and restores lysosomal cystine efflux in cystinosis. PLoS One 2019; 14:e0223954. [PMID: 31800572 PMCID: PMC6892560 DOI: 10.1371/journal.pone.0223954] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 10/02/2019] [Indexed: 12/19/2022] Open
Abstract
Background Cystinosis is a rare disorder caused by recessive mutations of the CTNS gene. Current therapy decreases cystine accumulation, thus slowing organ deterioration without reversing renal Fanconi syndrome or preventing eventual need for a kidney transplant.15-20% of cystinosis patients harbour at least one nonsense mutation in CTNS, leading to premature end of translation of the transcript. Aminoglycosides have been shown to permit translational read-through but have high toxicity level, especially in the kidney and inner ear. ELX-02, a modified aminoglycoside, retains it read-through ability without the toxicity. Methods and findings We ascertained the toxicity of ELX-02 in cells and in mice as well as the effect of ELX-02 on translational read-through of nonsense mutations in cystinotic mice and human cells. ELX-02 was not toxic in vitro or in vivo, and permitted read-through of nonsense mutations in cystinotic mice and human cells. Conclusions ELX-02 has translational read-through activity and produces a functional CTNS protein, as evidenced by reduced cystine accumulation. This reduction is comparable to cysteamine treatment. ELX-02 accumulates in the kidney but neither cytotoxicity nor nephrotoxicity was observed.
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Affiliation(s)
- Emma J. Brasell
- McGill University, Department of Human Genetics, Montreal, Canada
| | - Lee Lee Chu
- Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Murielle M. Akpa
- Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Idit Eshkar-Oren
- McGill University, Department of Experimental Medicine, Montreal, Canada
| | - Iris Alroy
- McGill University, Department of Experimental Medicine, Montreal, Canada
| | - Rachel Corsini
- Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Brian M. Gilfix
- Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Yojiro Yamanaka
- McGill University, Department of Human Genetics, Montreal, Canada
| | - Pedro Huertas
- McGill University, Department of Experimental Medicine, Montreal, Canada
| | - Paul Goodyer
- McGill University, Department of Human Genetics, Montreal, Canada
- Research Institute of the McGill University Health Centre, Montreal, Canada
- Montreal Children’s Hospital, Department of Nephrology, Montreal, Canada
- Eloxx Pharmaceuticals, Inc., Waltham, United States of America
- * E-mail:
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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5
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Brasell EJ, Chu L, El Kares R, Seo JH, Loesch R, Iglesias DM, Goodyer P. The aminoglycoside geneticin permits translational readthrough of the CTNS W138X nonsense mutation in fibroblasts from patients with nephropathic cystinosis. Pediatr Nephrol 2019; 34:873-881. [PMID: 30413946 DOI: 10.1007/s00467-018-4094-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/13/2018] [Accepted: 09/19/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND Cystinosis is an ultrarare disorder caused by mutations of the cystinosin (CTNS) gene, encoding a cystine-selective efflux channel in the lysosomes of all cells of the body. Oral therapy with cysteamine reduces intralysosomal cystine accumulation and slows organ deterioration but cannot reverse renal Fanconi syndrome nor prevent the eventual need for renal transplantation. A definitive therapeutic remains elusive. About 15% of cystinosis patients worldwide carry one or more nonsense mutations that halt translation of the CTNS protein. Aminoglycosides such as geneticin (G418) can bind to the mammalian ribosome, relax translational fidelity, and permit readthrough of premature termination codons to produce full-length protein. METHODS To ascertain whether aminoglycosides permit readthrough of the most common CTNS nonsense mutation, W138X, we studied the effect of G418 on patient fibroblasts. RESULTS G418 treatment induced translational readthrough of CTNSW138X constructs transfected into HEK293 cells and expression of full-length endogenous CTNS protein in homozygous W138X fibroblasts. CONCLUSIONS Reduction in intracellular cystine indicates that the CTNS protein produced is functional as a cystine transporter. Interestingly, similar effects were seen even in W138X compound heterozygotes. These studies establish proof-of-principle for the potential of aminoglycosides to treat cystinosis and possibly other monogenic diseases caused by nonsense mutations.
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Affiliation(s)
- Emma J Brasell
- Department of Human Genetics, McGill University, Montreal, Québec, Canada
| | - LeeLee Chu
- The Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Québec, Canada
| | - Reyhan El Kares
- The Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Québec, Canada
| | - Jung Hwa Seo
- The Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Québec, Canada
| | | | | | - Paul Goodyer
- Department of Human Genetics, McGill University, Montreal, Québec, Canada. .,The Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Québec, Canada. .,Department of Experimental Medicine, McGill University, Montreal, Canada.
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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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Kandasamy P, Gyimesi G, Kanai Y, Hediger MA. Amino acid transporters revisited: New views in health and disease. Trends Biochem Sci 2018; 43:752-789. [PMID: 30177408 DOI: 10.1016/j.tibs.2018.05.003] [Citation(s) in RCA: 252] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 05/23/2018] [Accepted: 05/25/2018] [Indexed: 02/09/2023]
Abstract
Amino acid transporters (AATs) are membrane-bound transport proteins that mediate transfer of amino acids into and out of cells or cellular organelles. AATs have diverse functional roles ranging from neurotransmission to acid-base balance, intracellular energy metabolism, and anabolic and catabolic reactions. In cancer cells and diabetes, dysregulation of AATs leads to metabolic reprogramming, which changes intracellular amino acid levels, contributing to the pathogenesis of cancer, obesity and diabetes. Indeed, the neutral amino acid transporters (NATs) SLC7A5/LAT1 and SLC1A5/ASCT2 are likely involved in several human malignancies. However, a clinical therapy that directly targets AATs has not yet been developed. The purpose of this review is to highlight the structural and functional diversity of AATs, their diverse physiological roles in different tissues and organs, their wide-ranging implications in human diseases and the emerging strategies and tools that will be necessary to target AATs therapeutically.
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Affiliation(s)
- Palanivel Kandasamy
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
| | - Gergely Gyimesi
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
| | - Yoshikatsu Kanai
- Division of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.
| | - Matthias A Hediger
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland.
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Zhang J, Johnson JL, He J, Napolitano G, Ramadass M, Rocca C, Kiosses WB, Bucci C, Xin Q, Gavathiotis E, Cuervo AM, Cherqui S, Catz SD. Cystinosin, the small GTPase Rab11, and the Rab7 effector RILP regulate intracellular trafficking of the chaperone-mediated autophagy receptor LAMP2A. J Biol Chem 2017; 292:10328-10346. [PMID: 28465352 DOI: 10.1074/jbc.m116.764076] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 04/28/2017] [Indexed: 12/12/2022] Open
Abstract
The lysosomal storage disease cystinosis, caused by cystinosin deficiency, is characterized by cell malfunction, tissue failure, and progressive renal injury despite cystine-depletion therapies. Cystinosis is associated with defects in chaperone-mediated autophagy (CMA), but the molecular mechanisms are incompletely understood. Here, we show CMA substrate accumulation in cystinotic kidney proximal tubule cells. We also found mislocalization of the CMA lysosomal receptor LAMP2A and impaired substrate translocation into the lysosome caused by defective CMA in cystinosis. The impaired LAMP2A trafficking and localization were rescued either by the expression of wild-type cystinosin or by the disease-associated point mutant CTNS-K280R, which has no cystine transporter activity. Defective LAMP2A trafficking in cystinosis was found to associate with decreased expression of the small GTPase Rab11 and the Rab7 effector RILP. Defective Rab11 trafficking in cystinosis was rescued by treatment with small-molecule CMA activators. RILP expression was restored by up-regulation of the transcription factor EB (TFEB), which was down-regulated in cystinosis. Although LAMP2A expression is independent of TFEB, TFEB up-regulation corrected lysosome distribution and lysosomal LAMP2A localization in Ctns-/- cells but not Rab11 defects. The up-regulation of Rab11, Rab7, or RILP, but not its truncated form RILP-C33, rescued LAMP2A-defective trafficking in cystinosis, whereas dominant-negative Rab11 or Rab7 impaired LAMP2A trafficking. Treatment of cystinotic cells with a CMA activator increased LAMP2A localization at the lysosome and increased cell survival. Altogether, we show that LAMP2A trafficking is regulated by cystinosin, Rab11, and RILP and that CMA up-regulation is a potential clinically relevant mechanism to increase cell survival in cystinosis.
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Affiliation(s)
- Jinzhong Zhang
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Jennifer L Johnson
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Jing He
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Gennaro Napolitano
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Mahalakshmi Ramadass
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Celine Rocca
- the Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California 92093-0734
| | - William B Kiosses
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037
| | - Cecilia Bucci
- the Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Via Provinciale Monteroni n. 165, 73100 Lecce, Italy, and
| | - Qisheng Xin
- the Departments of Biochemistry and.,Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | | | - Ana María Cuervo
- Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Stephanie Cherqui
- the Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California 92093-0734
| | - Sergio D Catz
- From the Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California 92037,
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Veys KR, D'Hauwers KW, van Dongen AJCM, Janssen MC, Besouw MTP, Goossens E, van den Heuvel LP, Wetzels AAMM, Levtchenko EN. First Successful Conception Induced by a Male Cystinosis Patient. JIMD Rep 2017; 38:1-6. [PMID: 28405942 DOI: 10.1007/8904_2017_19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/06/2017] [Accepted: 03/09/2017] [Indexed: 12/17/2022] Open
Abstract
Cystinosis is a rare autosomal recessive lysosomal storage disease characterized by multi-organ cystine accumulation, leading to renal failure and extra-renal organ dysfunction. Azoospermia of unknown origin is the main cause of infertility in all male cystinosis patients. Although spermatogenesis has shown to be intact at the testicular level in some patients, no male cystinosis patient has been reported yet to have successfully induced conception.We present the first successful conception ever reported, induced by a 27-year-old male renal transplant infantile nephropathic cystinosis patient through percutaneous epididymal sperm aspiration (PESA) followed by intracytoplasmatic sperm injection (ICSI). After 36 weeks and 6 days of an uncomplicated pregnancy, a dichorial diamniotic (DCDA) twin was born with an appropriate weight for gestational age and in an apparently healthy status. Moreover, we demonstrate that the sperm of epididymal origin in selected male cystinosis patients can be viable for inducing successful conception.Our observation opens a new perspective in life for many male cystinosis patients whom nowadays have become adults, by showing that despite azoospermia fathering a child can be realized. In addition, our findings raise questions about the possibility of sperm cryopreservation at a young age in these patients.
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Affiliation(s)
- Koenraad R Veys
- Department of Pediatric Nephrology, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium. .,Department of Growth and Regeneration, Unit of Organ Systems, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
| | - Kathleen W D'Hauwers
- Department of Urology, Radboud University Medical Center, Philips van Leydenlaan 15, 6562 EX, Nijmegen, The Netherlands
| | - Angelique J C M van Dongen
- Department of Gynaecology, Radboud University Medical Center, Philips van Leydenlaan 15, 6562 EX, Nijmegen, The Netherlands
| | - Mirian C Janssen
- Department of Internal Medicine, Unit of Metabolic Diseases, Radboud University Medical Center, Philips van Leydenlaan 15, 6562 EX, Nijmegen, The Netherlands
| | - Martine T P Besouw
- Department of Growth and Regeneration, Unit of Organ Systems, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Ellen Goossens
- Department of Reproduction, Biology of the Testis, Genetics and Regenerative Medicine, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090, Brussels, Belgium
| | - Lambert P van den Heuvel
- Department of Growth and Regeneration, Unit of Organ Systems, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Alex A M M Wetzels
- Department of Fertility, Radboud University Medical Center, Philips van Leydenlaan 15, 6562 EX, Nijmegen, The Netherlands
| | - Elena N Levtchenko
- Department of Pediatric Nephrology, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium.,Department of Growth and Regeneration, Unit of Organ Systems, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
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10
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Cystinosin-LKG rescues cystine accumulation and decreases apoptosis rate in cystinotic proximal tubular epithelial cells. Pediatr Res 2017; 81:113-119. [PMID: 27656773 DOI: 10.1038/pr.2016.184] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 08/10/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND Nephropathic cystinosis is a lysosomal storage disease that is caused by mutations in the CTNS gene encoding a cystine/proton symporter cystinosin and an isoform cystinosin-LKG which is generated by an alternative splicing of exon 12. We have investigated the physiological role of the cystinosin-LKG that is widely expressed in epithelial tissues. METHODS We have analyzed the intracellular localization and the function of the cystinosin-LKG conjugated with DsRed (cystinosin-LKG-RFP) in Madin-Darby canine kidney cells (MDCK II) and in proximal tubular epithelial cells carrying a deletion of the CTNS gene (cystinotic PTEC), respectively. RESULTS Cystinosin-LKG-RFP colocalized with markers of lysosomes, late endosomes and was also expressed on the apical surface of polarized MDCK II cells. Moreover, immune-electron microscopy images of MDCK II cells overexpressing cystinosin-LKG-RFP showed stacked lamellar membranes inside perinuclear lysosomal structures. To study the role of LKG-isoform, we have investigated cystine accumulation and apoptosis that have been described in cystinotic cells. Cystinosin-LKG decreased cystine levels by approximately 10-fold similarly to cystinosin-RFP. The levels of TNFα- and actinomycin D-inducted apoptosis dropped in cystinotic cells expressing LKG-isoform. This effect was also similar to the main isoform. CONCLUSION Our results suggest that cystinosin-LKG and cystinosin move similar functional activities in cells.
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11
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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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Bellomo F, Taranta A, Petrini S, Venditti R, Rocchetti MT, Rega LR, Corallini S, Gesualdo L, De Matteis MA, Emma F. Carboxyl-Terminal SSLKG Motif of the Human Cystinosin-LKG Plays an Important Role in Plasma Membrane Sorting. PLoS One 2016; 11:e0154805. [PMID: 27148969 PMCID: PMC4858208 DOI: 10.1371/journal.pone.0154805] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 04/19/2016] [Indexed: 11/18/2022] Open
Abstract
Cystinosin mediates an ATP-dependent cystine efflux from lysosomes and causes, if mutated, nephropathic cystinosis, a rare inherited lysosomal storage disease. Alternative splicing of the last exon of the cystinosin sequence produces the cystinosin-LKG isoform that is characterized by a different C-terminal region causing changes in the subcellular distribution of the protein. We have constructed RFP-tagged proteins and demonstrated by site-directed mutagenesis that the carboxyl-terminal SSLKG sequence of cystinosin-LKG is an important sorting motif that is required for efficient targeting the protein to the plasma membrane, where it can mediate H+ coupled cystine transport. Deletion of the SSLKG sequence reduced cystinosin-LKG expression in the plasma membrane and cystine transport by approximately 30%, and induced significant accumulation of the protein in the Golgi apparatus and in lysosomes. Cystinosin-LKG, unlike the canonical isoform, also moves to the lysosomes by the indirect pathway, after endocytic retrieval from the plasma membrane, mainly by a clathrin-mediated endocytosis. Nevertheless, silencing of AP-2 triggers the clathrin-independent endocytosis, showing the complex adaptability of cystinosin-LKG trafficking.
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Affiliation(s)
- Francesco Bellomo
- Department of Nephrology-Urology, Division of Nephrology and Dialysis, Bambino Gesù Children’s Hospital and Research Institute, Rome, Italy
- * E-mail:
| | - Anna Taranta
- Department of Nephrology-Urology, Division of Nephrology and Dialysis, Bambino Gesù Children’s Hospital and Research Institute, Rome, Italy
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Bambino Gesù Children’s Hospital and Research Institute, Rome, Italy
| | - Rossella Venditti
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli (NA), Italy
| | - Maria Teresa Rocchetti
- Department of Emergency and Organ Transplantation (DETO), Nephrology, Dialysis and Transplantation Unit, University of Bari Aldo Moro, Bari, Italy
| | - Laura Rita Rega
- Department of Nephrology-Urology, Division of Nephrology and Dialysis, Bambino Gesù Children’s Hospital and Research Institute, Rome, Italy
| | - Serena Corallini
- Department of Nephrology-Urology, Division of Nephrology and Dialysis, Bambino Gesù Children’s Hospital and Research Institute, Rome, Italy
| | - Loreto Gesualdo
- Department of Emergency and Organ Transplantation (DETO), Nephrology, Dialysis and Transplantation Unit, University of Bari Aldo Moro, Bari, Italy
| | | | - Francesco Emma
- Department of Nephrology-Urology, Division of Nephrology and Dialysis, Bambino Gesù Children’s Hospital and Research Institute, Rome, Italy
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13
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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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14
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Andrzejewska Z, Névo N, Thomas L, Bailleux A, Chauvet V, Benmerah A, Antignac C. Lysosomal Targeting of Cystinosin Requires AP-3. Traffic 2015; 16:712-26. [PMID: 25753619 DOI: 10.1111/tra.12277] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 02/20/2015] [Accepted: 02/23/2015] [Indexed: 01/28/2023]
Abstract
Cystinosin is a lysosomal cystine transporter defective in cystinosis, an autosomal recessive lysosomal storage disorder. It is composed of seven transmembrane (TM) domains and contains two lysosomal targeting motifs: a tyrosine-based signal (GYDQL) in its C-terminal tail and a non-classical motif in its fifth inter-TM loop. Using the yeast two-hybrid system, we showed that the GYDQL motif specifically interacted with the μ subunit of the adaptor protein complex 3 (AP-3). Moreover, cell surface biotinylation and total internal reflection fluorescence microscopy revealed that cystinosin was partially mislocalized to the plasma membrane (PM) in AP-3-depleted cells. We generated a chimeric CD63 protein to specifically analyze the function of the GYDQL motif. This chimeric protein was targeted to lysosomes in a manner similar to cystinosin and was partially mislocalized to the PM in AP-3 knockdown cells where it also accumulated in the trans-Golgi network and early endosomes. Together with the fact that the surface levels of cystinosin and of the CD63-GYDQL chimeric protein were not increased when clathrin-mediated endocytosis was impaired, our data show that the tyrosine-based motif of cystinosin is a 'strong' AP-3 interacting motif responsible for lysosomal targeting of cystinosin by a direct intracellular pathway.
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Affiliation(s)
- Zuzanna Andrzejewska
- Inserm U1163, Laboratory of Hereditary Kidney Diseases, Paris, France.,Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Nathalie Névo
- Inserm U1163, Laboratory of Hereditary Kidney Diseases, Paris, France.,Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Lucie Thomas
- Inserm U1163, Laboratory of Hereditary Kidney Diseases, Paris, France.,Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Anne Bailleux
- Inserm U1163, Laboratory of Hereditary Kidney Diseases, Paris, France.,Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Véronique Chauvet
- Inserm U1163, Laboratory of Hereditary Kidney Diseases, Paris, France.,Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Alexandre Benmerah
- Inserm U1163, Laboratory of Hereditary Kidney Diseases, Paris, France.,Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Corinne Antignac
- Inserm U1163, Laboratory of Hereditary Kidney Diseases, Paris, France.,Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France.,Assistance Publique - Hôpitaux de Paris (AP-HP), Department of Genetics, Necker Hospital, Paris,, France
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15
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Emma F, Nesterova G, Langman C, Labbé A, Cherqui S, Goodyer P, Janssen MC, Greco M, Topaloglu R, Elenberg E, Dohil R, Trauner D, Antignac C, Cochat P, Kaskel F, Servais A, Wühl E, Niaudet P, Van't Hoff W, Gahl W, Levtchenko E. Nephropathic cystinosis: an international consensus document. Nephrol Dial Transplant 2014; 29 Suppl 4:iv87-94. [PMID: 25165189 DOI: 10.1093/ndt/gfu090] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cystinosis is caused by mutations in the CTNS gene (17p13.2), which encodes for a lysosomal cystine/proton symporter termed cystinosin. It is the most common cause of inherited renal Fanconi syndrome in young children. Because of its rarity, the diagnosis and specific treatment of cystinosis are frequently delayed, which has a significant impact on the overall prognosis. In this document, we have summarized expert opinions on several aspects of the disease to improve knowledge and provide guidance for diagnosis and treatment.
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Affiliation(s)
- Francesco Emma
- Division of Nephrology and Dialysis, Bambino Gesu` Children's Hospital - IRCCS, Rome, Italy
| | - Galina Nesterova
- Section on Human Biochemical Genetics, Human Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-1851, USA
| | - Craig Langman
- Kidney Diseases, Feinberg School of Medicine, Northwestern University and the Ann and Robert H Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Antoine Labbé
- Quinze-Vingts National Ophthalmology Hospital, Paris and Versailles Saint-Quentin-en-Yvelines University, Versailles, France Clinical Investigations Center, INSERM 503, Quinze-Vingts National Ophthalmology Hospital, Paris, France
| | - Stephanie Cherqui
- Division of Genetics, Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Paul Goodyer
- Department of Pediatrics, McGill University, Montreal Children's Hospital, Montreal, Québec, Canada
| | - Mirian C Janssen
- Department of Internal Medicine, Radboud University Medical Centre Nijmegen, Nijmegen, The Netherlands
| | - Marcella Greco
- Division of Nephrology and Dialysis, Bambino Gesu` Children's Hospital - IRCCS, Rome, Italy
| | - Rezan Topaloglu
- Division of Pediatric Nephrology, Department of Pediatrics, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Ewa Elenberg
- Renal Service, Texas Children's Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Ranjan Dohil
- Department of Pediatrics, Rady Children's Hospital, San Diego, University of California San Diego, San Diego, CA, USA
| | - Doris Trauner
- Department of Neurosciences, University of California, San Diego, School of Medicine, San Diego, CA, USA
| | - Corinne Antignac
- Laboratory of Inherited Kidney Diseases, Inserm UMR 1163, Paris, France Paris Descartes-Sorbonne Paris Cité University, Imagine Institute, Paris, France APHP, Department of Genetics, Necker Hospital, Paris, France
| | - Pierre Cochat
- Centre de référence des maladies rénales rares, Hospices Civils de Lyon and Université Claude-Bernard Lyon 1, Lyon, France
| | - Frederick Kaskel
- Pediatric Nephrology, Children's Hospital at Montefiore, Bronx, NY, USA
| | - Aude Servais
- Department of Adult Nephrology, Hôpital Necker-Enfants Malades, APHP, Paris Descartes University, Paris, France
| | - Elke Wühl
- Division of Pediatric Nephrology, Center of Pediatrics and Adolescent Medicine, University of Heidelberg, Heidelberg, Germany
| | - Patrick Niaudet
- Université Paris Descartes, Hôpital Necker-Enfants Malades, Paris 75015, France
| | | | - William Gahl
- Section on Human Biochemical Genetics, Human Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-1851, USA
| | - Elena Levtchenko
- Department of Pediatric Nephrology and Growth and Regeneration, University Hospitals Leuven, Katholieke Universiteit Leuven, Leuven, Belgium
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16
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Abstract
Cystinosis is an autosomal recessive inherited lysosomal storage disease. It is characterized by generalized proximal tubular dysfunction known as renal Fanconi syndrome and causes end-stage renal disease by the age of about 10 years if left untreated. Extrarenal organs are also affected, including the thyroid gland, gonads, pancreas, liver, muscle, and brain. Treatment consists of administration of cysteamine, resulting in depletion of cystine that is trapped inside the lysosomes. Since cysteamine has a short half-life, it should be administered every 6 hours. Recently, a new delayed-release formulation was marketed, that should be administered every 12 hours. The first studies comparing both cysteamine formulations show comparable results regarding white blood cell cystine depletion (which serves as a measure for cystine accumulation in the body), while a slightly lower daily dose of cysteamine can be used.
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Affiliation(s)
- Martine Tp Besouw
- Department of Pediatric Nephrology, University Hospitals Leuven, Belgium ; Laboratory of Pediatrics, Catholic University Leuven, Leuven, Belgium
| | - Elena N Levtchenko
- Department of Pediatric Nephrology, University Hospitals Leuven, Belgium ; Laboratory of Pediatrics, Catholic University Leuven, Leuven, Belgium
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17
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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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18
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Kelemen O, Convertini P, Zhang Z, Wen Y, Shen M, Falaleeva M, Stamm S. Function of alternative splicing. Gene 2013; 514:1-30. [PMID: 22909801 PMCID: PMC5632952 DOI: 10.1016/j.gene.2012.07.083] [Citation(s) in RCA: 509] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/21/2012] [Accepted: 07/30/2012] [Indexed: 12/15/2022]
Abstract
Almost all polymerase II transcripts undergo alternative pre-mRNA splicing. Here, we review the functions of alternative splicing events that have been experimentally determined. The overall function of alternative splicing is to increase the diversity of mRNAs expressed from the genome. Alternative splicing changes proteins encoded by mRNAs, which has profound functional effects. Experimental analysis of these protein isoforms showed that alternative splicing regulates binding between proteins, between proteins and nucleic acids as well as between proteins and membranes. Alternative splicing regulates the localization of proteins, their enzymatic properties and their interaction with ligands. In most cases, changes caused by individual splicing isoforms are small. However, cells typically coordinate numerous changes in 'splicing programs', which can have strong effects on cell proliferation, cell survival and properties of the nervous system. Due to its widespread usage and molecular versatility, alternative splicing emerges as a central element in gene regulation that interferes with almost every biological function analyzed.
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Affiliation(s)
- Olga Kelemen
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Paolo Convertini
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Zhaiyi Zhang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Yuan Wen
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Manli Shen
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Marina Falaleeva
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
| | - Stefan Stamm
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky, United States of America
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19
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Iglesias DM, El-Kares R, Taranta A, Bellomo F, Emma F, Besouw M, Levtchenko E, Toelen J, van den Heuvel L, Chu L, Zhao J, Young YK, Eliopoulos N, Goodyer P. Stem cell microvesicles transfer cystinosin to human cystinotic cells and reduce cystine accumulation in vitro. PLoS One 2012; 7:e42840. [PMID: 22912749 PMCID: PMC3418268 DOI: 10.1371/journal.pone.0042840] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 07/11/2012] [Indexed: 11/25/2022] Open
Abstract
Cystinosis is a rare disease caused by homozygous mutations of the CTNS gene, encoding a cystine efflux channel in the lysosomal membrane. In Ctns knockout mice, the pathologic intralysosomal accumulation of cystine that drives progressive organ damage can be reversed by infusion of wildtype bone marrow-derived stem cells, but the mechanism involved is unclear since the exogeneous stem cells are rarely integrated into renal tubules. Here we show that human mesenchymal stem cells, from amniotic fluid or bone marrow, reduce pathologic cystine accumulation in co-cultured CTNS mutant fibroblasts or proximal tubular cells from cystinosis patients. This paracrine effect is associated with release into the culture medium of stem cell microvesicles (100–400 nm diameter) containing wildtype cystinosin protein and CTNS mRNA. Isolated stem cell microvesicles reduce target cell cystine accumulation in a dose-dependent, Annexin V-sensitive manner. Microvesicles from stem cells expressing CTNSRed transfer tagged CTNS protein to the lysosome/endosome compartment of cystinotic fibroblasts. Our observations suggest that exogenous stem cells may reprogram the biology of mutant tissues by direct microvesicle transfer of membrane-associated wildtype molecules.
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Affiliation(s)
- Diana M. Iglesias
- Department of Pediatrics, Montreal Children's Hospital Research Institute, McGill University, Montréal, Québec, Canada
| | - Reyhan El-Kares
- Department of Pediatrics, Montreal Children's Hospital Research Institute, McGill University, Montréal, Québec, Canada
| | - Anna Taranta
- U.O.C. di Nefrologia e Dialisi, Ospedale Pediatrico Bambino Gesù, Rome, Italy
| | - Francesco Bellomo
- U.O.C. di Nefrologia e Dialisi, Ospedale Pediatrico Bambino Gesù, Rome, Italy
| | - Francesco Emma
- U.O.C. di Nefrologia e Dialisi, Ospedale Pediatrico Bambino Gesù, Rome, Italy
| | - Martine Besouw
- Department of Pediatric Nephrology University Hospitals Leuven, Laboratory of Pediatrics, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Elena Levtchenko
- Department of Pediatric Nephrology University Hospitals Leuven, Laboratory of Pediatrics, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Jaan Toelen
- Department of Pediatric Nephrology University Hospitals Leuven, Laboratory of Pediatrics, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Lambertus van den Heuvel
- Department of Pediatric Nephrology University Hospitals Leuven, Laboratory of Pediatrics, Katholieke Universiteit Leuven, Leuven, Belgium
| | - LeeLee Chu
- Department of Pediatrics, Montreal Children's Hospital Research Institute, McGill University, Montréal, Québec, Canada
| | - Jing Zhao
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | - Yoon Kow Young
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
| | - Nicoletta Eliopoulos
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montréal, Québec, Canada
- Division of Surgical Research, Department of Surgery, McGill University, Montréal, Québec, Canada
- Department of Oncology, McGill University, Montréal, Québec, Canada
| | - Paul Goodyer
- Department of Pediatrics, Montreal Children's Hospital Research Institute, McGill University, Montréal, Québec, Canada
- * E-mail:
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20
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Taranta A, Petrini S, Citti A, Boldrini R, Corallini S, Bellomo F, Levtchenko E, Emma F. Distribution of cystinosin-LKG in human tissues. Histochem Cell Biol 2012; 138:351-63. [PMID: 22544350 DOI: 10.1007/s00418-012-0958-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2012] [Indexed: 12/31/2022]
Abstract
Nephropathic cystinosis is multisystemic progressive disorder caused by mutations of CTNS gene that encodes for the lysosomal cystine co-transporter cystinosin, and for a less abundant isoform termed cystinosin-LKG, which is expressed in not only lysosomes but also other cell compartments. To overcome the absence of high-quality antibodies against cystinosin, we have obtained a rabbit antiserum against cystinosin-LKG and have analyzed in human tissues the expression of the two known cystinosin isoforms by RT-PCR, and the expression of cystinosin-LKG by immunohistochemistry. In most tissues, CTNS-LKG represents 5-20 % of CTNS transcripts, with the exception of the testis that expresses both isoforms in equal proportions. Cystinosin-LKG was found to be highly expressed in renal tubular cells, pancreatic islets of Langerhans, Leydig cells of the testis, mucoserous glands of the bronchial wall, melanocytes and keratinocytes. These results are parallel with many features of cystinosis, such as early onset Fanconi syndrome, male infertility, diabetes mellitus and hypopigmentation. Intermediate expression levels were of the LKG isoform observed in the gastro-intestinal tract and thyroid glands; low levels of expression were observed in the brain, skeletal and cardiac muscles.
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Affiliation(s)
- Anna Taranta
- Division of Nephrology, Department of Nephrology and Urology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
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21
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Corallini S, Taranta A, Bellomo F, Palma A, Pastore A, Emma F. Transcriptional and posttranscriptional regulation of the CTNS gene. Pediatr Res 2011; 70:130-5. [PMID: 21508882 DOI: 10.1203/pdr.0b013e3182200187] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cell cysteine (Cys) levels and/or the [Cys/CySS] redox potential have been shown to regulate mRNA levels of the CTNS gene, which encodes for a lysosomal cystine (CySS) carrier that is defective in cystinosis. To investigate the mechanisms involved CTNS mRNA regulation, different portions of the CTNS promotor were cloned into a luciferase vector and transfected in HK2 cells. A 1.5-2.4-fold increase in luciferase activity was observed when cells were incubated in culture medium containing low CySS concentrations. Conversely, CTNS mRNA levels decreased by 47-56% in the presence of N-acetyl-L-cysteine (NAC). Chase experiments with actinomycin D (ActD) demonstrated a 3-fold stabilization of the CTNS mRNA when cells were cultured in low CySS medium for 48 h. Treatment of control cells with cyclohexamide (CHX) increased CTNS mRNA levels, suggesting that CHX blocked the synthesis of proteins involved in mRNA degradation or in repression of the CTNS gene. Finally, in vitro binding assays showed increased binding (30-110%) of the Sp-1 transcription factor to two regions of the CTNS promotor when cells were incubated in low CySS medium. These results indicate that the CTNS gene is actively regulated at the transcriptional and posttranscriptional levels and suggest that CTNS plays a pivotal role in regulating cell thiol concentrations.
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Affiliation(s)
- Serena Corallini
- Division of Nephrology and Dialysis, Bambino Gesù Children's Hospital and Research Institute, 00165 Rome, Italy
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22
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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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23
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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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24
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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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Ruivo R, Anne C, Sagné C, Gasnier B. Molecular and cellular basis of lysosomal transmembrane protein dysfunction. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:636-49. [DOI: 10.1016/j.bbamcr.2008.12.008] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 12/10/2008] [Accepted: 12/11/2008] [Indexed: 02/04/2023]
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Monnens L, Levtchenko E. Evaluation of the proximal tubular function in hereditary renal Fanconi syndrome. Nephrol Dial Transplant 2008; 23:2719-22. [DOI: 10.1093/ndt/gfn373] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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