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Medaer L, David D, Smits M, Levtchenko E, Sampaolesi M, Gijsbers R. Residual Cystine Transport Activity for Specific Infantile and Juvenile CTNS Mutations in a PTEC-Based Addback Model. Cells 2024; 13:646. [PMID: 38607085 PMCID: PMC11011962 DOI: 10.3390/cells13070646] [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: 03/10/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/13/2024] Open
Abstract
Cystinosis is a rare, autosomal recessive, lysosomal storage disease caused by mutations in the gene CTNS, leading to cystine accumulation in the lysosomes. While cysteamine lowers the cystine levels, it does not cure the disease, suggesting that CTNS exerts additional functions besides cystine transport. This study investigated the impact of infantile and juvenile CTNS mutations with discrepant genotype/phenotype correlations on CTNS expression, and subcellular localisation and function in clinically relevant cystinosis cell models to better understand the link between genotype and CTNS function. Using CTNS-depleted proximal tubule epithelial cells and patient-derived fibroblasts, we expressed a selection of CTNSmutants under various promoters. EF1a-driven expression led to substantial overexpression, resulting in CTNS protein levels that localised to the lysosomal compartment. All CTNSmutants tested also reversed cystine accumulation, indicating that CTNSmutants still exert transport activity, possibly due to the overexpression conditions. Surprisingly, even CTNSmutants expression driven by the less potent CTNS and EFS promoters reversed the cystine accumulation, contrary to the CTNSG339R missense mutant. Taken together, our findings shed new light on CTNS mutations, highlighting the need for robust assessment methodologies in clinically relevant cellular models and thus paving the way for better stratification of cystinosis patients, and advocating for the development of more personalized therapy.
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Affiliation(s)
- Louise Medaer
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium; (L.M.); (M.S.)
| | - Dries David
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium; (L.M.); (M.S.)
| | - Maxime Smits
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium; (L.M.); (M.S.)
- Leuven Viral Vector Core, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Elena Levtchenko
- Department of Paediatric Nephrology & Development and Regeneration, University Hospitals Leuven & KU Leuven, 3000 Leuven, Belgium;
- Department of Paediatric Nephrology, Amsterdam University Medical Centre, 1081 Amsterdam, The Netherlands
| | - Maurilio Sampaolesi
- Translational Cardiology Laboratory, Department of Development and Regeneration, Stem Cell Institute, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium;
| | - Rik Gijsbers
- Laboratory of Molecular Virology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium; (L.M.); (M.S.)
- Leuven Viral Vector Core, Faculty of Medicine, KU Leuven, 3000 Leuven, Belgium
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2
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Rossi MN, Matteo V, Diomedi-Camassei F, De Leo E, Devuyst O, Lamkanfi M, Caiello I, Loricchio E, Bellomo F, Taranta A, Emma F, De Benedetti F, Prencipe G. Nlrp2 deletion ameliorates kidney damage in a mouse model of cystinosis. Front Immunol 2024; 15:1373224. [PMID: 38633264 PMCID: PMC11021658 DOI: 10.3389/fimmu.2024.1373224] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/18/2024] [Indexed: 04/19/2024] Open
Abstract
Cystinosis is a rare autosomal recessive disorder caused by mutations in the CTNS gene that encodes cystinosin, a ubiquitous lysosomal cystine/H+ antiporter. The hallmark of the disease is progressive accumulation of cystine and cystine crystals in virtually all tissues. At the kidney level, human cystinosis is characterized by the development of renal Fanconi syndrome and progressive glomerular and interstitial damage leading to end-stage kidney disease in the second or third decade of life. The exact molecular mechanisms involved in the pathogenesis of renal disease in cystinosis are incompletely elucidated. We have previously shown upregulation of NLRP2 in human cystinotic proximal tubular epithelial cells and its role in promoting inflammatory and profibrotic responses. Herein, we have investigated the role of NLRP2 in vivo using a mouse model of cystinosis in which we have confirmed upregulation of Nlrp2 in the renal parenchyma. Our studies show that double knock out Ctns-/- Nlrp2-/- animals exhibit delayed development of Fanconi syndrome and kidney tissue damage. Specifically, we observed at 4-6 months of age that animals had less glucosuria and calciuria and markedly preserved renal tissue, as assessed by significantly lower levels of inflammatory cell infiltration, tubular atrophy, and interstitial fibrosis. Also, the mRNA expression of some inflammatory mediators (Cxcl1 and Saa1) and the rate of apoptosis were significantly decreased in 4-6-month old kidneys harvested from Ctns-/- Nlrp2-/- mice compared to those obtained from Ctns-/-mice. At 12-14 months of age, renal histological was markedly altered in both genetic models, although double KO animals had lower degree of polyuria and low molecular weight proteinuria and decreased mRNA expression levels of Il6 and Mcp1. Altogether, these data indicate that Nlrp2 is a potential pharmacological target for delaying progression of kidney disease in cystinosis.
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Affiliation(s)
- Marianna Nicoletta Rossi
- Laboratory of Immuno-Rheumatology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
- Department of Science, University of Rome “Roma Tre”, Rome, Italy
| | - Valentina Matteo
- Laboratory of Immuno-Rheumatology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Francesca Diomedi-Camassei
- Department of Laboratories, Pathology Unit, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Ester De Leo
- Division of Nephrology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Olivier Devuyst
- Mechanisms of Inherited Kidney Disorders Group, Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Mohamed Lamkanfi
- Laboratory of Medical Immunology, Department of Internal Medicine and Paediatrics, Ghent University, Ghent, Belgium
| | - Ivan Caiello
- Laboratory of Immuno-Rheumatology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Elena Loricchio
- Laboratory of Immuno-Rheumatology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Francesco Bellomo
- Division of Nephrology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Anna Taranta
- Division of Nephrology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Francesco Emma
- Division of Nephrology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Fabrizio De Benedetti
- Laboratory of Immuno-Rheumatology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
| | - Giusi Prencipe
- Laboratory of Immuno-Rheumatology, Bambino Gesù Children’s Hospital, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Roma, Italy
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Csorba A, Katona G, Budai-Szűcs M, Balogh-Weiser D, Molnár P, Maka E, Kazsoki A, Vajna M, Zelkó R, Nagy ZZ, Balogh GT. A Comparative Pharmacokinetic Study for Cysteamine-Containing Eye Drops as an Orphan Topical Therapy in Cystinosis. Int J Mol Sci 2024; 25:1623. [PMID: 38338900 PMCID: PMC10855117 DOI: 10.3390/ijms25031623] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 02/12/2024] Open
Abstract
Cystinosis is a low-prevalence lysosomal storage disease. The pathomechanism involves abnormal functioning of the cystinosine lysosomal cystine transporter (CTNS), causing intraliposomal accumulation of the amino acid cysteine disulfide, which crystallizes and deposits in several parts of the body. The most common ophthalmic complication of cystinosis is the deposition of "gold dust" cystine crystals on the cornea, which already occurs in infancy and leads to severe photosensitivity and dry eyes as it gradually progresses with age. In the specific treatment of cystinosis, preparations containing cysteamine (CYA) are used. The availability of commercialized eyedrops for the targeted treatment is scarce, and only Cystadrops® are commercially available with strong limitations. Thus, magistral CYA-containing compounded eyedrops (CYA-CED) could have a key role in patient care; however, a rationally designed comprehensive study on the commercialized and magistral products is still missing. This work aims to build up a comprehensive study about commercialized and magistral CYA eye drops, involving pharmacokinetic and physicochemical characterization (applying mucoadhesivity, rheology test, investigation of drug release, and parallel artificial membrane permeability assays), as well as ex vivo tests, well supported by statistical analysis.
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Affiliation(s)
- Anita Csorba
- Department of Ophthalmology, Semmelweis University, Mária Street 39, H-1085 Budapest, Hungary
| | - Gábor Katona
- Institute of Pharmaceutical Technology and Regulatory Affairs, Faculty of Pharmacy, University of Szeged, Eötvös Street 6, H-6720 Szeged, Hungary
| | - Mária Budai-Szűcs
- Institute of Pharmaceutical Technology and Regulatory Affairs, Faculty of Pharmacy, University of Szeged, Eötvös Street 6, H-6720 Szeged, Hungary
| | - Diána Balogh-Weiser
- Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3, H-1111 Budapest, Hungary
| | - Péter Molnár
- Molteam Llc., Mélyfúró Street 4, H-1151 Budapest, Hungary
| | - Erika Maka
- Department of Ophthalmology, Semmelweis University, Mária Street 39, H-1085 Budapest, Hungary
| | - Adrienn Kazsoki
- University Pharmacy Department of Pharmacy Administration, Semmelweis University, Hőgyes Endre Street 7-9, H-1092 Budapest, Hungary
| | - Márton Vajna
- University Pharmacy Department of Pharmacy Administration, Semmelweis University, Hőgyes Endre Street 7-9, H-1092 Budapest, Hungary
| | - Romána Zelkó
- University Pharmacy Department of Pharmacy Administration, Semmelweis University, Hőgyes Endre Street 7-9, H-1092 Budapest, Hungary
| | - Zoltán Zsolt Nagy
- Department of Ophthalmology, Semmelweis University, Mária Street 39, H-1085 Budapest, Hungary
| | - György T. Balogh
- Department of Pharmaceutical Chemistry, Semmelweis University, Hőgyes Endre Street 7-9, H-1092 Budapest, Hungary
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Luciani A, Devuyst O. The CTNS-MTORC1 axis couples lysosomal cystine to epithelial cell fate decisions and is a targetable pathway in cystinosis. Autophagy 2024; 20:202-204. [PMID: 37621073 PMCID: PMC10761040 DOI: 10.1080/15548627.2023.2250165] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/09/2023] [Accepted: 08/11/2023] [Indexed: 08/26/2023] Open
Abstract
Differentiation and fate decisions are critical for the epithelial cells lining the proximal tubule (PT) of the kidney, but the signals involved remain unknown. Defective cystine mobilization from lysosomes through CTNS (cystinosin, lysosomal cystine transporter), which is mutated in cystinosis, triggers the dedifferentiation and dysfunction of the PT cells, causing kidney disease and severe metabolic complications. Using preclinical models and physiologically relevant cellular systems, along with functional assays and a generative artificial intelligence (AI)-powered engine, we found that cystine storage imparted by CTNS deficiency stimulates Ragulator-RRAG GTPase-dependent recruitment of MTORC1 and its constitutive activation. In turn, this diverts the catabolic trajectories and differentiating states of PT cells toward growth and proliferation, disrupting homeostasis and their specialized functions. Therapeutic MTORC1 inhibition by using low doses of rapamycin corrects lysosome function and differentiation downstream of cystine storage and ameliorates PT dysfunction in preclinical models of cystinosis. These discoveries suggest that cystine may act as a lysosomal fasting signal that tailors MTORC1 signaling to direct fate decisions in the kidney PT epithelium, highlighting novel therapeutic paradigms for cystinosis and other lysosome-related disorders.
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Affiliation(s)
| | - Olivier Devuyst
- Institute of Physiology, University of Zurich, Zurich, Switzerland
- Institute for Rare Diseases, UCLouvain Medical School, Brussels, Belgium
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Baysal İ, Yabanoglu-Ciftci S, Nemutlu E, Eylem CC, Gök-Topak ED, Ulubayram K, Kır S, Gulhan B, Uçar G, Ozaltin F, Topaloglu R. Omic Studies on In Vitro Cystinosis Model: siRNA-Mediated CTNS Gene Silencing in HK-2 Cells. J Transl Med 2024; 104:100287. [PMID: 37949358 DOI: 10.1016/j.labinv.2023.100287] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 10/10/2023] [Accepted: 11/03/2023] [Indexed: 11/12/2023] Open
Abstract
Cystinosis is an autosomal recessive disease caused by mutations in the CTNS gene encoding a protein called cystinosine, which is a lysosomal cystine transporter. Disease-causing mutations lead to accumulation of cystine crystals in the lysosomes, thereby causing dysfunction of vital organs. Determination of the increased leukocyte cystine level is one of the most used methods for diagnosis. However, this method is expensive, difficult to perform, and may yield different results in different laboratories. In this study, a disease model was created with CTNS gene-silenced HK2 cells, which can mimic cystinosis in cell culture, and multiomics methods (ie, proteomics, metabolomics, and fluxomics) were implemented at this cell culture to investigate new biomarkers for the diagnosis. CTNS-silenced cell line exhibited distinct metabolic profiles compared with the control cell line. Pathway analysis highlighted significant alterations in various metabolic pathways, including alanine, aspartate, and glutamate metabolism; glutathione metabolism; aminoacyl-tRNA biosynthesis; arginine and proline metabolism; beta-alanine metabolism; ascorbate and aldarate metabolism; and histidine metabolism upon CTNS silencing. Fluxomics analysis revealed increased cycle rates of Krebs cycle intermediates such as fumarate, malate, and citrate, accompanied by enhanced activation of inorganic phosphate and ATP production. Furthermore, proteomic analysis unveiled differential expression levels of key proteins involved in crucial cellular processes. Notably, peptidyl-prolyl cis-trans isomerase A, translation elongation factor 1-beta (EF-1beta), and 60S acidic ribosomal protein decreased in CTNS-silenced cells. Additionally, levels of P0 and tubulin α-1A chain were reduced, whereas levels of 40S ribosomal protein S8 and Midasin increased. Overall, our study, through the utilization of an in vitro cystinosis model and comprehensive multiomics approach, led to the way toward the identification of potential new biomarkers while offering valuable insights into the pathogenesis of cystinosis.
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Affiliation(s)
- İpek Baysal
- Vocational School of Health Services, Pharmacy Services Programme, Ankara, Türkiye
| | - Samiye Yabanoglu-Ciftci
- Department of Biochemistry, Faculty of Pharmacy, Hacettepe University, Sihhiye, Ankara, Türkiye.
| | - Emirhan Nemutlu
- Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Sihhiye, Ankara, Türkiye
| | - Cemil Can Eylem
- Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Sihhiye, Ankara, Türkiye
| | - Elif Damla Gök-Topak
- Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Sihhiye, Ankara, Türkiye; Department of Analytical Chemistry, Faculty of Pharmacy, Lokman Hekim University, Sogutozu, Ankara, Türkiye
| | - Kezban Ulubayram
- Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Hacettepe University, Sihhiye, Ankara, Türkiye
| | - Sedef Kır
- Department of Analytical Chemistry, Faculty of Pharmacy, Hacettepe University, Sihhiye, Ankara, Türkiye
| | - Bora Gulhan
- Department of Pediatric Nephrology, Hacettepe University School of Medicine, Sihhiye, Ankara, Türkiye
| | - Gülberk Uçar
- Department of Biochemistry, Faculty of Pharmacy, Hacettepe University, Sihhiye, Ankara, Türkiye
| | - Fatih Ozaltin
- Department of Pediatric Nephrology, Hacettepe University School of Medicine, Sihhiye, Ankara, Türkiye; Nephrogenetics Laboratory, Department of Pediatric Nephrology, Hacettepe University School of Medicine, Sihhiye, Ankara, Türkiye; Center for Genomics and Rare Diseases, Hacettepe University, Sihhiye, Ankara, Türkiye; Department of Bioinformatics, Hacettepe University, Institute of Health Sciences, Ankara, Türkiye
| | - Rezan Topaloglu
- Department of Pediatric Nephrology, Hacettepe University School of Medicine, Sihhiye, Ankara, Türkiye.
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Lashilola S, Xu W, Azimpour K, McCarthy M, Carlot S, Game D, van der Voort J. Impact of compliance to oral cysteamine treatment on the costs of Kidney failure in patients with nephropathic cystinosis in the United Kingdom. BMC Nephrol 2023; 24:351. [PMID: 38031005 PMCID: PMC10688492 DOI: 10.1186/s12882-023-03392-y] [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: 11/17/2022] [Accepted: 11/08/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND Nephropathic Cystinosis (NC), a rare disease characterised by intra-lysosomal accumulation of cystine, results in progressive kidney failure (KF). Compliance to lifelong oral cysteamine, the only therapy, is often compromised. The relationship between compliance and costs of NC has not been previously formally assessed. The present study evaluates the impact of compliance on lifetime (direct) costs of treating KF in NC patients in the United Kingdom. METHODS A three-state (KF-free, post-KF, death) partitioned survival model was developed for hypothetical 'Good Compliance' (GC) and 'Poor Compliance' (PC) cohorts. Survival in the KF-free state was determined by a published regression function of composite compliance score (CCS). The CCS is a summation of annual compliance scores (ACS) over treatment duration prior to KF. ACSs are indexed on annual (average) leukocyte cystine levels (LCL). The Poor Compliance cohort was defined to reflect NC patients in a previous study with a mean LCL of 2.35 nmols nmol half-cystine/mg protein over the study period - and an estimated mean ACS of 1.64 over a 13.4 year treatment duration. The Good Compliance cohort was assumed to have an ACS of 2.25 for 21 years. Major KF costs were evaluated - i.e., dialysis, kidney transplants, and subsequent monitoring. RESULTS The mean CCS was 47 for the GC and 22 for the PC cohort respectively, corresponding to estimated lifetime KF costs of £92,370 and £117,830 respectively - i.e., a cost saving of £25,460/patient, or £1,005/patient for every 1-unit improvement in CCS. CONCLUSION This analysis indicates that lifetime costs of KF in NC can be reduced through improved treatment compliance with oral cysteamine.
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Affiliation(s)
| | - Weiwei Xu
- Real World Insights, IQVIA, Amsterdam, the Netherlands.
| | - Khashayar Azimpour
- Global Health Economics and Outcome Research, Chiesi, Boston, United States
| | - Michael McCarthy
- Health Economics and Outcomes Research, MAP Patient Access, Cambridge, UK
| | - Sara Carlot
- Global Rare Diseases Business Unit, Chiesi Farmaceutici S.p.A, Parma, Italy
| | - David Game
- Department of Nephrology, Guy's Hospital, London, UK
| | - Judith van der Voort
- Department of Paediatric Nephrology, University Hospital of Wales, Cardiff, Wales
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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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8
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Venkatarangan V, Zhang W, Yang X, Thoene J, Hahn SH, Li M. ER-associated degradation in cystinosis pathogenesis and the prospects of precision medicine. J Clin Invest 2023; 133:e169551. [PMID: 37561577 PMCID: PMC10541201 DOI: 10.1172/jci169551] [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: 02/13/2023] [Accepted: 08/08/2023] [Indexed: 08/12/2023] Open
Abstract
Cystinosis is a lysosomal storage disease that is characterized by the accumulation of dipeptide cystine within the lumen. It is caused by mutations in the cystine exporter, cystinosin. Most of the clinically reported mutations are due to the loss of transporter function. In this study, we identified a rapidly degrading disease variant, referred to as cystinosin(7Δ). We demonstrated that this mutant is retained in the ER and degraded via the ER-associated degradation (ERAD) pathway. Using genetic and chemical inhibition methods, we elucidated the roles of HRD1, p97, EDEMs, and the proteasome complex in cystinosin(7Δ) degradation pathway. Having understood the degradation mechanisms, we tested some chemical chaperones previously used for treating CFTR F508Δ and demonstrated that they could facilitate the folding and trafficking of cystinosin(7Δ). Strikingly, chemical chaperone treatment can reduce the lumenal cystine level by approximately 70%. We believe that our study conclusively establishes the connection between ERAD and cystinosis pathogenesis and demonstrates the possibility of using chemical chaperones to treat cystinosin(7Δ).
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Affiliation(s)
- Varsha Venkatarangan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Weichao Zhang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Xi Yang
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jess Thoene
- Department of Pediatrics, Division of Pediatric Genetics, Metabolism & Genomic Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan, USA
| | - Si Houn Hahn
- University of Washington School of Medicine, Department of Pediatrics, Seattle Children’s Hospital, Seattle, Washington, USA
| | - Ming Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
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9
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Bondue T, Kouraich A, Berlingerio SP, Veys K, Marie S, Alsaad KO, Al-Sabban E, Levtchenko E, van den Heuvel L. The Pitfall of White Blood Cell Cystine Measurement to Diagnose Juvenile Cystinosis. Int J Mol Sci 2023; 24:ijms24021253. [PMID: 36674769 PMCID: PMC9864853 DOI: 10.3390/ijms24021253] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Abstract
Cystinosis is an autosomal recessive lysosomal storage disease, caused by mutations in the CTNS gene, resulting in multi-organ cystine accumulation. Three forms of cystinosis are distinguished: infantile and juvenile nephropathic cystinosis affecting kidneys and other organs such as the eyes, endocrine system, muscles, and brain, and adult ocular cystinosis affecting only the eyes. Currently, elevated white blood cell (WBC) cystine content is the gold standard for the diagnosis of cystinosis. We present a patient with proteinuria at adolescent age and corneal cystine crystals, but only slightly elevated WBC cystine levels (1.31 ½ cystine/mg protein), precluding the diagnosis of nephropathic cystinosis. We demonstrate increased levels of cystine in skin fibroblasts and urine-derived kidney cells (proximal tubular epithelial cells and podocytes), that were higher than the values observed in the WBC and healthy control. CTNS gene analysis shows the presence of a homozygous missense mutation (c.590 A > G; p.Asn177Ser), previously described in the Arab population. Our observation underlines that low WBC cystine levels can be observed in patients with juvenile cystinosis, which may delay the diagnosis and timely administration of cysteamine. In such patients, the diagnosis can be confirmed by cystine measurement in slow-dividing cells and by molecular analysis of the CTNS gene.
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Affiliation(s)
- Tjessa Bondue
- Laboratory of Pediatric Nephrology, Department of Development and Regeneration, KU Leuven Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Anas Kouraich
- Laboratory of Pediatric Nephrology, Department of Development and Regeneration, KU Leuven Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Sante Princiero Berlingerio
- Laboratory of Pediatric Nephrology, Department of Development and Regeneration, KU Leuven Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Koenraad Veys
- Laboratory of Pediatric Nephrology, Department of Development and Regeneration, KU Leuven Campus Gasthuisberg, 3000 Leuven, Belgium
- Department of Pediatrics, AZ Delta Campus Torhout, 8820 Torhout, Belgium
| | - Sandrine Marie
- Laboratory of Inherited Metabolic Diseases/Biochemical Genetics, Cliniques Universitaires Saint-Luc, UC Louvain, 1200 Brussels, Belgium
| | - Khaled O. Alsaad
- Section of Histopathology, Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Centre, Riyadh 11533, Saudi Arabia
| | - Essam Al-Sabban
- Section of Pediatric Nephrology, Department of Pediatrics, King Faisal Specialist Hospital and Research Centre, Riyadh 11533, Saudi Arabia
| | - Elena Levtchenko
- Laboratory of Pediatric Nephrology, Department of Development and Regeneration, KU Leuven Campus Gasthuisberg, 3000 Leuven, Belgium
- Department of Pediatrics, University Hospitals Leuven Campus Gasthuisberg, 3000 Leuven, Belgium
| | - Lambertus van den Heuvel
- Laboratory of Pediatric Nephrology, Department of Development and Regeneration, KU Leuven Campus Gasthuisberg, 3000 Leuven, Belgium
- Department of Pediatrics, Division of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, HB-6524 Nijmegen, The Netherlands
- Correspondence:
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10
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Veys K, Berlingerio SP, David D, Bondue T, Held K, Reda A, van den Broek M, Theunis K, Janssen M, Cornelissen E, Vriens J, Diomedi-Camassei F, Gijsbers R, van den Heuvel L, Arcolino FO, Levtchenko E. Urine-Derived Kidney Progenitor Cells in Cystinosis. Cells 2022; 11:cells11071245. [PMID: 35406807 PMCID: PMC8997687 DOI: 10.3390/cells11071245] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/14/2022] [Accepted: 03/31/2022] [Indexed: 12/10/2022] Open
Abstract
Nephropathic cystinosis is an inherited lysosomal storage disorder caused by pathogenic variants in the cystinosin (CTNS) gene and is characterized by the excessive shedding of proximal tubular epithelial cells (PTECs) and podocytes into urine, development of the renal Fanconi syndrome and end-stage kidney disease (ESKD). We hypothesized that in compensation for epithelial cell losses, cystinosis kidneys undertake a regenerative effort, and searched for the presence of kidney progenitor cells (KPCs) in the urine of cystinosis patients. Urine was cultured in a specific progenitor medium to isolate undifferentiated cells. Of these, clones were characterized by qPCR, subjected to a differentiation protocol to PTECs and podocytes and assessed by qPCR, Western blot, immunostainings and functional assays. Cystinosis patients voided high numbers of undifferentiated cells in urine, of which various clonal cell lines showed a high capacity for self-renewal and expressed kidney progenitor markers, which therefore were assigned as cystinosis urine-derived KPCs (Cys-uKPCs). Cys-uKPC clones showed the capacity to differentiate between functional PTECs and/or podocytes. Gene addition with wild-type CTNS using lentiviral vector technology resulted in significant reductions in cystine levels. We conclude that KPCs present in the urine of cystinosis patients can be isolated, differentiated and complemented with CTNS in vitro, serving as a novel tool for disease modeling.
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Affiliation(s)
- Koenraad Veys
- Department of Pediatrics, University Hospitals Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium;
- Laboratory of Pediatric Nephrology, Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (S.P.B.); (T.B.); (A.R.); (L.v.d.H.); (F.O.A.)
| | - Sante Princiero Berlingerio
- Laboratory of Pediatric Nephrology, Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (S.P.B.); (T.B.); (A.R.); (L.v.d.H.); (F.O.A.)
| | - Dries David
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (D.D.); (R.G.)
| | - Tjessa Bondue
- Laboratory of Pediatric Nephrology, Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (S.P.B.); (T.B.); (A.R.); (L.v.d.H.); (F.O.A.)
| | - Katharina Held
- Laboratory of Endometrium, Endometriosis & Reproductive Medicine (LEERM), Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (K.H.); (J.V.)
| | - Ahmed Reda
- Laboratory of Pediatric Nephrology, Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (S.P.B.); (T.B.); (A.R.); (L.v.d.H.); (F.O.A.)
| | - Martijn van den Broek
- Department of Pathology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6524 Nijmegen, The Netherlands;
- Department of Pediatrics, Division of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, 6524 Nijmegen, The Netherlands;
| | - Koen Theunis
- Department of Human Genetics, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium;
| | - Mirian Janssen
- Department of Internal Medicine, Radboud University Medical Center, 6524 Nijmegen, The Netherlands;
| | - Elisabeth Cornelissen
- Department of Pediatrics, Division of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, 6524 Nijmegen, The Netherlands;
| | - Joris Vriens
- Laboratory of Endometrium, Endometriosis & Reproductive Medicine (LEERM), Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (K.H.); (J.V.)
| | - Francesca Diomedi-Camassei
- Unit of Pathology, Department of Laboratories, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy;
| | - Rik Gijsbers
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (D.D.); (R.G.)
- Leuven Viral Vector Core, KU Leuven, B-3000 Leuven, Belgium
| | - Lambertus van den Heuvel
- Laboratory of Pediatric Nephrology, Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (S.P.B.); (T.B.); (A.R.); (L.v.d.H.); (F.O.A.)
- Department of Pediatrics, Division of Pediatric Nephrology, Amalia Children’s Hospital, Radboud University Medical Center, 6524 Nijmegen, The Netherlands;
| | - Fanny O. Arcolino
- Laboratory of Pediatric Nephrology, Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (S.P.B.); (T.B.); (A.R.); (L.v.d.H.); (F.O.A.)
| | - Elena Levtchenko
- Department of Pediatrics, University Hospitals Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium;
- Laboratory of Pediatric Nephrology, Department of Development & Regeneration, KU Leuven Campus Gasthuisberg, B-3000 Leuven, Belgium; (S.P.B.); (T.B.); (A.R.); (L.v.d.H.); (F.O.A.)
- Correspondence: ; Tel.: +32-16-34-13-62
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11
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Goodman S, Khan M, Sharma J, Li Z, Cano J, Castellanos C, Estrada MV, Gertsman I, Cherqui S. Deficiency of the sedoheptulose kinase (Shpk) does not alter the ability of hematopoietic stem cells to rescue cystinosis in the mouse model. Mol Genet Metab 2021; 134:309-316. [PMID: 34823997 PMCID: PMC8935660 DOI: 10.1016/j.ymgme.2021.11.006] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/09/2021] [Accepted: 11/10/2021] [Indexed: 11/21/2022]
Abstract
Cystinosis is an autosomal recessive lysosomal storage disorder caused by mutations in the CTNS gene encoding the lysosomal cystine transporter, cystinosin, and leading to multi-organ degeneration including kidney failure. A clinical trial for cystinosis is ongoing to test the safety and efficacy of transplantation of autologous hematopoietic stem and progenitor cells (HSPCs) ex vivo gene-modified to introduce functional CTNS cDNA. Preclinical studies in Ctns-/- mice previously showed that a single HSPC transplantation led to significant tissue cystine decrease and long-term tissue preservation. The main mechanism of action involves the differentiation of the transplanted HSPCs into macrophages within tissues and transfer of cystinosin-bearing lysosomes to the diseased cells via tunneling nanotubes. However, a major concern was that the most common cystinosis-causing mutation in humans is a 57-kb deletion that eliminates not only CTNS but also the adjacent sedopheptulose kinase SHPK/CARKL gene encoding a metabolic enzyme that influences macrophage polarization. Here, we investigated if absence of Shpk could negatively impact the efficiency of transplanted HSPCs to differentiate into macrophages within tissues and then to prevent cystinosis rescue. We generated Shpk knockout mouse models and detected a phenotype consisting of perturbations in the pentose phosphate pathway (PPP), the metabolic shunt regulated by SHPK. Shpk-/- mice also recapitulated the urinary excretion of sedoheptulose and erythritol found in cystinosis patients homozygous for the 57-kb deletion. Transplantation of Shpk-/--HSPCs into Ctns-/- mice resulted in significant reduction in tissue cystine load and restoration of Ctns expression, as well as improved kidney architecture comparable to WT-HSPC recipients. Altogether, these data demonstrate that absence of SHPK does not alter the ability of HSPCs to rescue cystinosis, and then patients homozygous for the 57-kb deletion should benefit from ex vivo gene therapy and can be enrolled in the ongoing clinical trial. However, because of the limits inherent to animal models, outcomes of this patient population will be carefully compared to the other enrolled subjects.
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Affiliation(s)
- Spencer Goodman
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, CA, USA
| | - Meisha Khan
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, CA, USA
| | - Jay Sharma
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, CA, USA
| | - Zijie Li
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, CA, USA
| | - Jose Cano
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, CA, USA
| | - Carlos Castellanos
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, CA, USA
| | - Monica V Estrada
- Tissue Technology Shared Resource, Biorepository and Tissue Technology, Moores Cancer Center, University of California, San Diego, La Jolla, CA, USA
| | | | - Stephanie Cherqui
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, CA, USA.
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12
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Bellomo F, De Leo E, Taranta A, Giaquinto L, Di Giovamberardino G, Montefusco S, Rega LR, Pastore A, Medina DL, Di Bernardo D, De Matteis MA, Emma F. Drug Repurposing in Rare Diseases: An Integrative Study of Drug Screening and Transcriptomic Analysis in Nephropathic Cystinosis. Int J Mol Sci 2021; 22:ijms222312829. [PMID: 34884638 PMCID: PMC8657658 DOI: 10.3390/ijms222312829] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [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: 10/18/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 12/11/2022] Open
Abstract
Diagnosis and cure for rare diseases represent a great challenge for the scientific community who often comes up against the complexity and heterogeneity of clinical picture associated to a high cost and time-consuming drug development processes. Here we show a drug repurposing strategy applied to nephropathic cystinosis, a rare inherited disorder belonging to the lysosomal storage diseases. This approach consists in combining mechanism-based and cell-based screenings, coupled with an affordable computational analysis, which could result very useful to predict therapeutic responses at both molecular and system levels. Then, we identified potential drugs and metabolic pathways relevant for the pathophysiology of nephropathic cystinosis by comparing gene-expression signature of drugs that share common mechanisms of action or that involve similar pathways with the disease gene-expression signature achieved with RNA-seq.
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Affiliation(s)
- Francesco Bellomo
- Renal Diseases Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (E.D.L.); (A.T.); (L.R.R.)
- Correspondence: (F.B.); (F.E.)
| | - Ester De Leo
- Renal Diseases Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (E.D.L.); (A.T.); (L.R.R.)
| | - Anna Taranta
- Renal Diseases Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (E.D.L.); (A.T.); (L.R.R.)
| | - Laura Giaquinto
- Telethon InstituFte of Genetics and Medicine, 80078 Naples, Italy; (L.G.); (S.M.); (D.L.M.); (D.D.B.); (M.A.D.M.)
| | | | - Sandro Montefusco
- Telethon InstituFte of Genetics and Medicine, 80078 Naples, Italy; (L.G.); (S.M.); (D.L.M.); (D.D.B.); (M.A.D.M.)
| | - Laura Rita Rega
- Renal Diseases Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (E.D.L.); (A.T.); (L.R.R.)
| | - Anna Pastore
- Management Diagnostic Innovations Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy;
| | - Diego Luis Medina
- Telethon InstituFte of Genetics and Medicine, 80078 Naples, Italy; (L.G.); (S.M.); (D.L.M.); (D.D.B.); (M.A.D.M.)
| | - Diego Di Bernardo
- Telethon InstituFte of Genetics and Medicine, 80078 Naples, Italy; (L.G.); (S.M.); (D.L.M.); (D.D.B.); (M.A.D.M.)
- Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, 80138 Naples, Italy
| | - Maria Antonietta De Matteis
- Telethon InstituFte of Genetics and Medicine, 80078 Naples, Italy; (L.G.); (S.M.); (D.L.M.); (D.D.B.); (M.A.D.M.)
- Department of Medical Biotechnologies and Molecular Medicine, University of Naples Federico II, 80138 Naples, Italy
| | - Francesco Emma
- Renal Diseases Research Unit, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy; (E.D.L.); (A.T.); (L.R.R.)
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children’s Hospital, IRCCS, 00165 Rome, Italy
- Correspondence: (F.B.); (F.E.)
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13
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Gonzalez A, Cheung WW, Perens EA, Oliveira EA, Gertler A, Mak RH. A Leptin Receptor Antagonist Attenuates Adipose Tissue Browning and Muscle Wasting in Infantile Nephropathic Cystinosis-Associated Cachexia. Cells 2021; 10:1954. [PMID: 34440723 PMCID: PMC8393983 DOI: 10.3390/cells10081954] [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] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/19/2021] [Accepted: 07/24/2021] [Indexed: 12/12/2022] Open
Abstract
Mice lacking the functional cystinosin gene (Ctns-/-), a model of infantile nephropathic cystinosis (INC), exhibit the cachexia phenotype with adipose tissue browning and muscle wasting. Elevated leptin signaling is an important cause of chronic kidney disease-associated cachexia. The pegylated leptin receptor antagonist (PLA) binds to but does not activate the leptin receptor. We tested the efficacy of this PLA in Ctns-/- mice. We treated 12-month-old Ctns-/- mice and control mice with PLA (7 mg/kg/day, IP) or saline as a vehicle for 28 days. PLA normalized food intake and weight gain, increased fat and lean mass, decreased metabolic rate and improved muscle function. It also attenuated perturbations of energy homeostasis in adipose tissue and muscle in Ctns-/- mice. PLA attenuated adipose tissue browning in Ctns-/- mice. PLA increased gastrocnemius weight and fiber size as well as attenuated muscle fat infiltration in Ctns-/- mice. This was accompanied by correcting the increased expression of muscle wasting signaling while promoting the decreased expression of myogenesis in gastrocnemius of Ctns-/- mice. PLA attenuated aberrant expressed muscle genes that have been associated with muscle atrophy, increased energy expenditure and lipolysis in Ctns-/- mice. Leptin antagonism may represent a viable therapeutic strategy for adipose tissue browning and muscle wasting in INC.
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MESH Headings
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/metabolism
- Adipose Tissue, Brown/pathology
- Adipose Tissue, White/drug effects
- Adipose Tissue, White/metabolism
- Adipose Tissue, White/pathology
- Amino Acid Transport Systems, Neutral/genetics
- Amino Acid Transport Systems, Neutral/metabolism
- Animals
- Body Composition/drug effects
- Cachexia/etiology
- Cachexia/metabolism
- Cachexia/pathology
- Cachexia/prevention & control
- Cystinosis/complications
- Cystinosis/drug therapy
- Cystinosis/metabolism
- Cystinosis/pathology
- Disease Models, Animal
- Hormone Antagonists/pharmacology
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Atrophy/etiology
- Muscular Atrophy/metabolism
- Muscular Atrophy/pathology
- Muscular Atrophy/prevention & control
- Receptors, Leptin/antagonists & inhibitors
- Receptors, Leptin/metabolism
- Signal Transduction
- Mice
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Affiliation(s)
- Alex Gonzalez
- Division of Pediatric Nephrology, Rady Children’s Hospital, University of California, San Diego, CA 92093-0831, USA; (A.G.); (W.W.C.); (E.A.P.); (E.A.O.)
| | - Wai W. Cheung
- Division of Pediatric Nephrology, Rady Children’s Hospital, University of California, San Diego, CA 92093-0831, USA; (A.G.); (W.W.C.); (E.A.P.); (E.A.O.)
| | - Elliot A. Perens
- Division of Pediatric Nephrology, Rady Children’s Hospital, University of California, San Diego, CA 92093-0831, USA; (A.G.); (W.W.C.); (E.A.P.); (E.A.O.)
| | - Eduardo A. Oliveira
- Division of Pediatric Nephrology, Rady Children’s Hospital, University of California, San Diego, CA 92093-0831, USA; (A.G.); (W.W.C.); (E.A.P.); (E.A.O.)
- Health Sciences Postgraduate Program, School of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte 30130-100, MG, Brazil
| | - Arieh Gertler
- Institute of Biochemistry, Food Science and Nutrition, Hebrew University of Jerusalem, Rehovot 7610001, Israel;
| | - Robert H. Mak
- Division of Pediatric Nephrology, Rady Children’s Hospital, University of California, San Diego, CA 92093-0831, USA; (A.G.); (W.W.C.); (E.A.P.); (E.A.O.)
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14
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Myerowitz R, Puertollano R, Raben N. Impaired autophagy: The collateral damage of lysosomal storage disorders. EBioMedicine 2021; 63:103166. [PMID: 33341443 PMCID: PMC7753127 DOI: 10.1016/j.ebiom.2020.103166] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [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: 10/28/2020] [Revised: 11/25/2020] [Accepted: 11/26/2020] [Indexed: 12/12/2022] Open
Abstract
Lysosomal storage disorders (LSDs), which number over fifty, are monogenically inherited and caused by mutations in genes encoding proteins that are involved in lysosomal function. Lack of the functional protein results in storage of a distinctive material within the lysosomes, which for years was thought to determine the pathophysiology of the disorder. However, our current view posits that the primary storage material disrupts the normal role of the lysosome in the autophagic pathway resulting in the secondary storage of autophagic debris. It is this "collateral damage" which is common to the LSDs but nonetheless intricately nuanced in each. We have selected five LSDs resulting from defective proteins that govern widely different lysosomal functions including glycogen degradation (Pompe), lysosomal transport (Cystinosis), lysosomal trafficking (Danon), glycolipid degradation (Gaucher) and an unidentified function (Batten) and argue that despite the disparate functions, these proteins, when mutant, all impair the autophagic process uniquely.
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Affiliation(s)
- Rachel Myerowitz
- Department of Biology St. Mary's College of Maryland, St. Mary's City Maryland, 20686, USA
| | - Rosa Puertollano
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH, 50 South Dr./Room 3533, Bethesda, MD 20892, USA
| | - Nina Raben
- Cell and Developmental Biology Center, National Heart, Lung, and Blood Institute, NIH, 50 South Dr./Room 3533, Bethesda, MD 20892, USA.
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15
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Adelmann CH, Traunbauer AK, Chen B, Condon KJ, Chan SH, Kunchok T, Lewis CA, Sabatini DM. MFSD12 mediates the import of cysteine into melanosomes and lysosomes. Nature 2020; 588:699-704. [PMID: 33208952 PMCID: PMC7770032 DOI: 10.1038/s41586-020-2937-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [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: 12/09/2019] [Accepted: 08/28/2020] [Indexed: 12/12/2022]
Abstract
Dozens of genes contribute to the wide variation in human pigmentation. Many of these genes encode proteins that localize to the melanosome-the organelle, related to the lysosome, that synthesizes pigment-but have unclear functions1,2. Here we describe MelanoIP, a method for rapidly isolating melanosomes and profiling their labile metabolite contents. We use this method to study MFSD12, a transmembrane protein of unknown molecular function that, when suppressed, causes darker pigmentation in mice and humans3,4. We find that MFSD12 is required to maintain normal levels of cystine-the oxidized dimer of cysteine-in melanosomes, and to produce cysteinyldopas, the precursors of pheomelanin synthesis made in melanosomes via cysteine oxidation5,6. Tracing and biochemical analyses show that MFSD12 is necessary for the import of cysteine into melanosomes and, in non-pigmented cells, lysosomes. Indeed, loss of MFSD12 reduced the accumulation of cystine in lysosomes of fibroblasts from patients with cystinosis, a lysosomal-storage disease caused by inactivation of the lysosomal cystine exporter cystinosin7-9. Thus, MFSD12 is an essential component of the cysteine importer for melanosomes and lysosomes.
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Affiliation(s)
- Charles H Adelmann
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Anna K Traunbauer
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Brandon Chen
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kendall J Condon
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Sze Ham Chan
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Tenzin Kunchok
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Caroline A Lewis
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - David M Sabatini
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA, USA.
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De Rasmo D, Signorile A, De Leo E, Polishchuk EV, Ferretta A, Raso R, Russo S, Polishchuk R, Emma F, Bellomo F. Mitochondrial Dynamics of Proximal Tubular Epithelial Cells in Nephropathic Cystinosis. Int J Mol Sci 2019; 21:ijms21010192. [PMID: 31888107 PMCID: PMC6982165 DOI: 10.3390/ijms21010192] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [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: 11/29/2019] [Revised: 12/20/2019] [Accepted: 12/24/2019] [Indexed: 12/27/2022] Open
Abstract
Nephropathic cystinosis is a rare lysosomal storage disorder caused by mutations in CTNS gene leading to Fanconi syndrome. Independent studies reported defective clearance of damaged mitochondria and mitochondrial fragmentation in cystinosis. Proteins involved in the mitochondrial dynamics and the mitochondrial ultrastructure were analyzed in CTNS-/- cells treated with cysteamine, the only drug currently used in the therapy for cystinosis but ineffective to treat Fanconi syndrome. CTNS-/- cells showed an overexpression of parkin associated with deregulation of ubiquitination of mitofusin 2 and fission 1 proteins, an altered proteolytic processing of optic atrophy 1 (OPA1), and a decreased OPA1 oligomerization. According to molecular findings, the analysis of electron microscopy images showed a decrease of mitochondrial cristae number and an increase of cristae lumen and cristae junction width. Cysteamine treatment restored the fission 1 ubiquitination, the mitochondrial size, number and lumen of cristae, but had no effect on cristae junction width, making CTNS-/- tubular cells more susceptible to apoptotic stimuli.
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Affiliation(s)
- Domenico De Rasmo
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnology (IBIOM), National Research Council (CNR), 70124 Bari, Italy;
- Correspondence: (D.D.R.); (F.B.); Tel.: +39-080-5448516 (D.D.R.); +39-06-68592997 (F.B)
| | - Anna Signorile
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari “Aldo Moro”, 70124 Bari, Italy; (A.S.); (S.R.)
| | - Ester De Leo
- Renal Diseases Research Unit, Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital—IRCCS, 00146 Rome, Italy; (E.D.L.); (R.R.)
| | - Elena V. Polishchuk
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy; (E.V.P.); (R.P.)
| | - Anna Ferretta
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnology (IBIOM), National Research Council (CNR), 70124 Bari, Italy;
| | - Roberto Raso
- Renal Diseases Research Unit, Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital—IRCCS, 00146 Rome, Italy; (E.D.L.); (R.R.)
| | - Silvia Russo
- Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari “Aldo Moro”, 70124 Bari, Italy; (A.S.); (S.R.)
| | - Roman Polishchuk
- Telethon Institute of Genetics and Medicine, 80078 Pozzuoli, Italy; (E.V.P.); (R.P.)
| | - Francesco Emma
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children’s Hospital—IRCCS, 00165 Rome, Italy;
| | - Francesco Bellomo
- Renal Diseases Research Unit, Genetics and Rare Diseases Research Division, Bambino Gesù Children’s Hospital—IRCCS, 00146 Rome, Italy; (E.D.L.); (R.R.)
- Correspondence: (D.D.R.); (F.B.); Tel.: +39-080-5448516 (D.D.R.); +39-06-68592997 (F.B)
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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] [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: 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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18
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Goodman S, Naphade S, Khan M, Sharma J, Cherqui S. Macrophage polarization impacts tunneling nanotube formation and intercellular organelle trafficking. Sci Rep 2019; 9:14529. [PMID: 31601865 PMCID: PMC6787037 DOI: 10.1038/s41598-019-50971-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/23/2019] [Indexed: 01/21/2023] Open
Abstract
Tunneling nanotubes (TNTs) are cellular extensions enabling cytosol-to-cytosol intercellular interaction between numerous cell types including macrophages. Previous studies of hematopoietic stem and progenitor cell (HSPC) transplantation for the lysosomal storage disorder cystinosis have shown that HSPC-derived macrophages form TNTs to deliver cystinosin-bearing lysosomes to cystinotic cells, leading to tissue preservation. Here, we explored if macrophage polarization to either proinflammatory M1-like M(LPS/IFNγ) or anti-inflammatory M2-like M(IL-4/IL-10) affected TNT-like protrusion formation, intercellular transport and, ultimately, the efficacy of cystinosis prevention. We designed new automated image processing algorithms used to demonstrate that LPS/IFNγ polarization decreased bone marrow-derived macrophages (BMDMs) formation of protrusions, some of which displayed characteristics of TNTs, including cytoskeletal structure, 3D morphology and size. In contrast, co-culture of macrophages with cystinotic fibroblasts yielded more frequent and larger protrusions, as well as increased lysosomal and mitochondrial intercellular trafficking to the diseased fibroblasts. Unexpectedly, we observed normal protrusion formation and therapeutic efficacy following disruption of anti-inflammatory IL-4/IL-10 polarization in vivo by transplantation of HSPCs isolated from the Rac2-/- mouse model. Altogether, we developed unbiased image quantification systems that probe mechanistic aspects of TNT formation and function in vitro, while HSPC transplantation into cystinotic mice provides a complex in vivo disease model. While the differences between polarization cell culture and mouse models exemplify the oversimplicity of in vitro cytokine treatment, they simultaneously demonstrate the utility of our co-culture model which recapitulates the in vivo phenomenon of diseased cystinotic cells stimulating thicker TNT formation and intercellular trafficking from macrophages. Ultimately, we can use both approaches to expand the utility of TNT-like protrusions as a delivery system for regenerative medicine.
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Affiliation(s)
- Spencer Goodman
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Swati Naphade
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Meisha Khan
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Jay Sharma
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Stephanie Cherqui
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA.
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19
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Lobry T, Miller R, Nevo N, Rocca CJ, Zhang J, Catz SD, Moore F, Thomas L, Pouly D, Bailleux A, Guerrera IC, Gubler MC, Cheung WW, Mak RH, Montier T, Antignac C, Cherqui S. Interaction between galectin-3 and cystinosin uncovers a pathogenic role of inflammation in kidney involvement of cystinosis. Kidney Int 2019; 96:350-362. [PMID: 30928021 PMCID: PMC7269416 DOI: 10.1016/j.kint.2019.01.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [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: 07/18/2018] [Revised: 12/11/2018] [Accepted: 01/10/2019] [Indexed: 11/25/2022]
Abstract
Inflammation is involved in the pathogenesis of many disorders. However, the underlying mechanisms are often unknown. Here, we test whether cystinosin, the protein involved in cystinosis, is a critical regulator of galectin-3, a member of the β-galactosidase binding protein family, during inflammation. Cystinosis is a lysosomal storage disorder and, despite ubiquitous expression of cystinosin, the kidney is the primary organ impacted by the disease. Cystinosin was found to enhance lysosomal localization and degradation of galectin-3. In Ctns-/- mice, a mouse model of cystinosis, galectin-3 is overexpressed in the kidney. The absence of galectin-3 in cystinotic mice ameliorates pathologic renal function and structure and decreases macrophage/monocyte infiltration in the kidney of the Ctns-/-Gal3-/- mice compared to Ctns-/- mice. These data strongly suggest that galectin-3 mediates inflammation involved in kidney disease progression in cystinosis. Furthermore, galectin-3 was found to interact with the pro-inflammatory cytokine Monocyte Chemoattractant Protein-1, which stimulates the recruitment of monocytes/macrophages, and proved to be significantly increased in the serum of Ctns-/- mice and also patients with cystinosis. Thus, our findings highlight a new role for cystinosin and galectin-3 interaction in inflammation and provide an additional mechanistic explanation for the kidney disease of cystinosis. This may lead to the identification of new drug targets to delay cystinosis progression.
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Affiliation(s)
- Tatiana Lobry
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA; INSERM, U1078, Équipe 'Transfert de gènes et thérapie génique', Faculté de Médecine, Brest, France, and CHRU de Brest, Service de Génétique Moléculaire et d'histocompatibilité, Brest, France
| | - Roy Miller
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Nathalie Nevo
- INSERM, U1163, Imagine Institute, Laboratory of Hereditary Kidney Diseases, Paris, France; Paris Descartes-Sorbonne Paris Cité University, Paris, France
| | - Celine J Rocca
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Jinzhong Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Sergio D Catz
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Fiona Moore
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Lucie Thomas
- INSERM, U1163, Imagine Institute, Laboratory of Hereditary Kidney Diseases, Paris, France; Paris Descartes-Sorbonne Paris Cité University, Paris, France
| | - Daniel Pouly
- INSERM, U1163, Imagine Institute, Laboratory of Hereditary Kidney Diseases, Paris, France; Paris Descartes-Sorbonne Paris Cité University, Paris, France
| | - Anne Bailleux
- INSERM, U1163, Imagine Institute, Laboratory of Hereditary Kidney Diseases, Paris, France; Paris Descartes-Sorbonne Paris Cité University, Paris, France
| | - Ida Chiara Guerrera
- Proteomics Platform 3P5-Necker, Université Paris Descartes-Structure Fédérative de Recherche Necker, INSERM US24/CNRS UMS3633, Paris, France
| | - Marie-Claire Gubler
- INSERM, U1163, Imagine Institute, Laboratory of Hereditary Kidney Diseases, Paris, France; Paris Descartes-Sorbonne Paris Cité University, Paris, France
| | - Wai W Cheung
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Robert H Mak
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA
| | - Tristan Montier
- INSERM, U1078, Équipe 'Transfert de gènes et thérapie génique', Faculté de Médecine, Brest, France, and CHRU de Brest, Service de Génétique Moléculaire et d'histocompatibilité, Brest, France
| | - Corinne Antignac
- INSERM, U1163, Imagine Institute, Laboratory of Hereditary Kidney Diseases, Paris, France; Paris Descartes-Sorbonne Paris Cité University, Paris, France; Department of Genetics, Necker Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Stephanie Cherqui
- Department of Pediatrics, Division of Genetics, University of California, San Diego, La Jolla, California, USA.
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Gallego-Villar L, Hannibal L, Häberle J, Thöny B, Ben-Omran T, Nasrallah GK, Dewik AN, Kruger WD, Blom HJ. Cysteamine revisited: repair of arginine to cysteine mutations. J Inherit Metab Dis 2017; 40:555-567. [PMID: 28643139 PMCID: PMC5740875 DOI: 10.1007/s10545-017-0060-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/22/2017] [Accepted: 05/30/2017] [Indexed: 12/22/2022]
Abstract
Cysteamine is a small aminothiol endogenously derived from coenzyme A degradation. For some decades, synthetic cysteamine has been employed for the treatment of cystinosis, and new uses of the drug continue to emerge. In this review, we discuss the role of cysteamine in cellular and extracellular homeostasis and focus on the potential use of aminothiols to reconstitute the function of proteins harboring arginine (Arg) to cysteine (Cys) mutations, via repair of the Cys residue into a moiety that introduces an amino group, as seen in basic amino acid residues Lys and Arg. Cysteamine has been utilized in vitro and ex vivo in four different genetic disorders, and thus provides "proof of principle" that aminothiols can modify Cys residues. Other aminothiols such as mercaptoethylguanidine (MEG) with closer structural resemblance to the guanidinium moiety of Arg are under examination for their predicted enhanced capacity to reconstitute loss of function. Although the use of aminothiols holds clinical potential, more studies are required to refine specificity and treatment design. The efficacy of aminothiols to target proteins may vary substantially depending on their specific extracellular and intracellular locations. Redox potential, pH, and specific aminothiol abundance in each physiological compartment are expected to influence the reactivity and turnover of cysteamine and analogous drugs. Upcoming research will require the use of suitable cell and animal models featuring Arg to Cys mutations. Since, in general, Arg to Cys changes comprise about 8% of missense mutations, repair of this specific mutation may provide promising avenues for many genetic diseases.
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Affiliation(s)
- L Gallego-Villar
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, University Medical Centre Freiburg, Mathildenstrasse 1, 79106, Freiburg, Germany
| | - Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, University Medical Centre Freiburg, Mathildenstrasse 1, 79106, Freiburg, Germany
| | - J Häberle
- University Children's Hospital and Children's Research Center, Zurich, Switzerland
| | - B Thöny
- University Children's Hospital and Children's Research Center, Zurich, Switzerland
| | - T Ben-Omran
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - G K Nasrallah
- Department of Biomedical Sciences, College of Health Sciences, Qatar University, Doha, Qatar
- Biomedical Research Center, Qatar University, Doha, Qatar
| | - Al-N Dewik
- Clinical and Metabolic Genetics, Department of Pediatrics, Hamad Medical Corporation, Doha, Qatar
| | - W D Kruger
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, PA, USA
| | - H J Blom
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, University Medical Centre Freiburg, Mathildenstrasse 1, 79106, Freiburg, Germany.
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21
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Ivanova EA, Elmonem MA, Bongaerts I, Luyten T, Missiaen L, van den Heuvel LP, Levtchenko EN, Bultynck G. Ca(2+) signalling in human proximal tubular epithelial cells deficient for cystinosin. Cell Calcium 2016; 60:282-7. [PMID: 27451386 DOI: 10.1016/j.ceca.2016.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 07/03/2016] [Indexed: 11/17/2022]
Abstract
Nephropathic cystinosis is an autosomal recessive lysosomal storage disorder caused by loss-of-function mutations in the CTNS gene coding for the lysosomal cystine transporter, cystinosin. Recent studies have demonstrated that, apart from cystine accumulation in the lysosomes, cystinosin-deficient cells, especially renal proximal tubular epithelial cells are characterized by abnormal vesicle trafficking and endocytosis, possible lysosomal dysfunction and perturbed intracellular signalling cascades. It is therefore possible that Ca(2+) signalling is disturbed in cystinosis, as it has been demonstrated for other disorders associated with lysosomal dysfunction, such as Gaucher, Niemann-Pick type C and Alzheimer's diseases. In this study we investigated ATP-induced, IP3-induced and lysosomal Ca(2+) release in human proximal tubular epithelial cells derived from control and cystinotic patients. No major dysregulation of intracellular Ca(2+) dynamics was found, although ATP-induced Ca(2+) release appeared slightly sensitized in cystinotic cells compared to control cells. Hence, these subtle changes in Ca(2+) signals elicited by agonists may contribute to the pathogenesis of the disease.
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Affiliation(s)
- Ekaterina A Ivanova
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium
| | - Mohamed A Elmonem
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium; Cairo University, Faculty of Medicine, Department of Clinical and Chemical Pathology, Cairo, Egypt.
| | - Inge Bongaerts
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium
| | - Tomas Luyten
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Ludwig Missiaen
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium
| | - Lambertus P van den Heuvel
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium; Radboud University Medical Center, Department of Pediatric Nephrology, Nijmegen, The Netherlands
| | - Elena N Levtchenko
- KU Leuven and UZ Leuven, Department of Pediatric Nephrology & Growth and Regeneration, Leuven, Belgium
| | - Geert Bultynck
- KU Leuven, Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, Leuven, Belgium
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22
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Ivanova EA, van den Heuvel LP, Elmonem MA, De Smedt H, Missiaen L, Pastore A, Mekahli D, Bultynck G, Levtchenko EN. Altered mTOR signalling in nephropathic cystinosis. J Inherit Metab Dis 2016; 39:457-464. [PMID: 26909499 DOI: 10.1007/s10545-016-9919-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/22/2016] [Accepted: 02/02/2016] [Indexed: 11/27/2022]
Abstract
Lysosomes play a central role in regulating autophagy via activation of mammalian target of rapamycin complex 1 (mTORC1). We examined mTORC1 signalling in the lysosomal storage disease nephropathic cystinosis (MIM 219800), in which accumulation of autophagy markers has been previously demonstrated. Cystinosis is caused by mutations in the lysosomal cystine transporter cystinosin and initially affects kidney proximal tubules causing renal Fanconi syndrome, followed by a gradual development of end-stage renal disease and extrarenal complications. Using proximal tubular kidney cells obtained from healthy donors and from cystinotic patients, we demonstrate that cystinosin deficiency is associated with a perturbed mTORC1 signalling, delayed reactivation of mTORC1 after starvation and abnormal lysosomal retention of mTOR during starvation. These effects could not be reversed by treatment with cystine-depleting drug cysteamine. Altered mTORC1 signalling can contribute to the development of proximal tubular dysfunction in cystinosis and points to new possibilities in therapeutic intervention through modulation of mTORC-dependent signalling cascades.
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Affiliation(s)
- Ekaterina A Ivanova
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
| | - Lambertus P van den Heuvel
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
- Department of Pediatric Nephrology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mohamed A Elmonem
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
- Department of Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Humbert De Smedt
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Ludwig Missiaen
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Anna Pastore
- Laboratory of Proteomics and Metabolomics, Children's Hospital and Research Institute "Bambino Gesù" IRCCS, Rome, Italy
| | - Djalila Mekahli
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium
| | - Greet Bultynck
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Elena N Levtchenko
- Department of Growth and Regeneration, KU Leuven and University Hospitals Leuven, UZ Herestraat 49, 3000, Leuven, Belgium.
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23
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Gaide Chevronnay HP, Janssens V, Van Der Smissen P, Liao XH, Abid Y, Nevo N, Antignac C, Refetoff S, Cherqui S, Pierreux CE, Courtoy PJ. A mouse model suggests two mechanisms for thyroid alterations in infantile cystinosis: decreased thyroglobulin synthesis due to endoplasmic reticulum stress/unfolded protein response and impaired lysosomal processing. Endocrinology 2015; 156:2349-64. [PMID: 25811319 PMCID: PMC4430621 DOI: 10.1210/en.2014-1672] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Thyroid hormones are released from thyroglobulin (Tg) in lysosomes, which are impaired in infantile/nephropathic cystinosis. Cystinosis is a lysosomal cystine storage disease due to defective cystine exporter, cystinosin. Cystinotic children develop subclinical and then overt hypothyroidism. Why hypothyroidism is the most frequent and earliest endocrine complication of cystinosis is unknown. We here defined early alterations in Ctns(-/-) mice thyroid and identified subcellular and molecular mechanisms. At 9 months, T4 and T3 plasma levels were normal and TSH was moderately increased (∼4-fold). By histology, hyperplasia and hypertrophy of most follicles preceded colloid exhaustion. Increased immunolabeling for thyrocyte proliferation and apoptotic shedding indicated accelerated cell turnover. Electron microscopy revealed endoplasmic reticulum (ER) dilation, apical lamellipodia indicating macropinocytic colloid uptake, and lysosomal cystine crystals. Tg accumulation in dilated ER contrasted with mRNA down-regulation. Increased expression of ER chaperones, glucose-regulated protein of 78 kDa and protein disulfide isomerase, associated with alternative X-box binding protein-1 splicing, revealed unfolded protein response (UPR) activation by ER stress. Decreased Tg mRNA and ER stress suggested reduced Tg synthesis. Coordinated increase of UPR markers, activating transcription factor-4 and C/EBP homologous protein, linked ER stress to apoptosis. Hormonogenic cathepsins were not altered, but lysosome-associated membrane protein-1 immunolabeling disclosed enlarged vesicles containing iodo-Tg and impaired lysosomal fusion. Isopycnic fractionation showed iodo-Tg accumulation in denser lysosomes, suggesting defective lysosomal processing and hormone release. In conclusion, Ctns(-/-) mice showed the following alterations: 1) compensated primary hypothyroidism and accelerated thyrocyte turnover; 2) impaired Tg production linked to ER stress/UPR response; and 3) altered endolysosomal trafficking and iodo-Tg processing. The Ctns(-/-) thyroid is useful to study disease progression and evaluate novel therapies.
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Affiliation(s)
- H P Gaide Chevronnay
- Cell Biology Unit (H.P.G.C., V.J., P.V.D.S., Y.A., C.E.P., P.J.C.), de Duve Institute and Université Catholique de Louvain, 1200 Brussels, Belgium; Departments of Medicine (X.H.L., S.R.) and Pediatrics and Genetics (S.R), The University of Chicago, Chicago, Illinois 60637; INSERM, Unité 1163 (N.N., C.A.), Hôpital Necker-Enfants Malades and Université Paris Descartes, Sorbonne Paris Cité, Institut Imagine, 75015 Paris, France; and Department of Pediatrics (S.C.), Division of Genetics, University of California, San Diego, San Diego, California 92161
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24
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Gultekingil Keser A, Topaloglu R, Bilginer Y, Besbas N. Long-term endocrinologic complications of cystinosis. Minerva Pediatr 2014; 66:123-130. [PMID: 24835445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
AIM Cystinosis is a rare autosomal recessive disorder that is characterized by defective cystine transport from lysosomes to cytoplasm and cystine crystal accumulation damaging many organs and tissues especially kidneys but extrarenal systems such as endocrine system. We aim to investigate endocrinologic complications of cystinosis METHODS In our study, twenty one patients were reviewed retrospectively for endocrinologic complications. RESULTS Eighteen (85.7%) had short stature, out of nine patients who reached pubertal age, five (55.5%) had pubertal delay, five patients (23.8%) had overt hypothyroidism and five patients (23.8%) had subclinical hypothyroidism with only elevated thyroid stimulating hormone (TSH) levels, seven (33.3%) had glucose intolerance, two (9.5%) had diabetes mellitus. Relation of these complications to age, renal functions and the dosage of cysteamine were studied. CONCLUSION Endocrinologic complications of cystinosis can be seen in pediatric population and it is important to understand underlying mechanisms.
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Labbé A, Baudouin C, Deschênes G, Loirat C, Charbit M, Guest G, Niaudet P. A new gel formulation of topical cysteamine for the treatment of corneal cystine crystals in cystinosis: the Cystadrops OCT-1 study. Mol Genet Metab 2014; 111:314-320. [PMID: 24440466 DOI: 10.1016/j.ymgme.2013.12.298] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Revised: 12/29/2013] [Accepted: 12/29/2013] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To establish the safety and efficacy of a new gel formulation of cysteamine hydrochloride (CH) eye drops, for the treatment of corneal complications of nephropathic cystinosis. DESIGN Open label dose response clinical trial. PARTICIPANTS Eight patients with infantile nephropathic cystinosis including 4 children, 3 adolescents, and 1 adult (mean age at inclusion, 12.1 ± 4.6 years) treated with CH 0.1% eye drops. INTERVENTION Patients were treated, in both eyes, with the control CH 0.1% eye drop formulation on average 4 times daily for one month and then switched to Cystadrops® at the same dose frequency. Based on clinical ocular findings, the dose regimen was adapted at D30 and D90 in order to decrease the frequency of instillation. After D90, this dose frequency was maintained, except in cases of crystal density worsening. Patients had a follow-up visit every 6 months during 48 months. MAIN OUTCOME MEASURES Safety assessment consisted of adverse event and serious adverse event monitoring and recording at each visit. For the efficacy study, the primary endpoint was the corneal cystine crystal density measured with an in vivo confocal microscopy (IVCM) score. RESULTS All patients completed the study. During the 4-year study period, neither serious adverse events nor significant adverse events related to the study drug were reported. After switching to Cystadrops®, the IVCM total score decreased from baseline to D90 by a mean of 28.6 ± 17.5% (p<0.001). From D90 to M48, the IVCM total score remained stable and significantly decreased as compared to that at D1 despite a reduced dose regimen from D90. At M48, the mean IVCM total score was 8.13 ± 4.15, decreased by a mean 29.9 ± 26.29% from D1 (p = 0.001), with a reduced number of instillations compared to that at D1. The IVCM total score and photophobia were significantly correlated (p = 0.04). CONCLUSION This study provides evidence that Cystadrops® gel is superior to the CH 0.1% formulation in terms of efficacy and has a good safety profile over a long follow-up period.
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Affiliation(s)
- Antoine Labbé
- Department of Ophthalmology 3, Quinze-Vingts National Eye Center, Paris, France; Center for Clinical Investigations INSERM 503, Quinze-Vingts National Eye Center, Paris, France; Department of Ophthalmology, Ambroise Paré Hospital, AP-HP, UFR Paris-île de France Ouest, University of Versailles Saint-Quentin-en-Yvelines, Versailles, France.
| | - Christophe Baudouin
- Department of Ophthalmology 3, Quinze-Vingts National Eye Center, Paris, France; Center for Clinical Investigations INSERM 503, Quinze-Vingts National Eye Center, Paris, France; Department of Ophthalmology, Ambroise Paré Hospital, AP-HP, UFR Paris-île de France Ouest, University of Versailles Saint-Quentin-en-Yvelines, Versailles, France
| | - Georges Deschênes
- Department of Pediatric Nephrology, Robert Debré Hospital, AP-HP, Paris, France
| | - Chantal Loirat
- Department of Pediatric Nephrology, Robert Debré Hospital, AP-HP, Paris, France
| | - Marina Charbit
- Department of Pediatric Nephrology, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Geneviève Guest
- Department of Pediatric Nephrology, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Patrick Niaudet
- Department of Pediatric Nephrology, Necker-Enfants Malades Hospital, AP-HP, Paris, France
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Bellomo F, Corallini S, Pastore A, Palma A, Laurenzi C, Emma F, Taranta A. Modulation of CTNS gene expression by intracellular thiols. Free Radic Biol Med 2010; 48:865-72. [PMID: 20079424 DOI: 10.1016/j.freeradbiomed.2010.01.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 12/30/2009] [Accepted: 01/05/2010] [Indexed: 10/20/2022]
Abstract
The cysteine/cystine (Cys/CySS) couple represents one of the major cell thiol/disulfide systems and is involved in the regulation of several metabolic pathways and the cell redox state. Nephropathic cystinosis (NC) is an autosomal recessive disease characterized by renal cellular dysfunction due to mutations in the CTNS gene, which encodes cystinosin, a CySS lysosomal transporter. To analyze the mechanisms involved in cell damage in NC, we have investigated the effects of CTNS gene overexpression or inhibition on cell thiol/disulfide systems and vice versa. Overexpression of the CTNS gene had no remarkable effect on intracellular Cys/CySS and GSH/GSSG redox state. Silencing the CTNS gene increased cell CySS and Cys and decreased cell GSH and GSSG and increased mildly the redox state of the Cys/CySS-couple. Extracellular CySS and Cys deprivation for 48 h caused an oxidation of the Cys/CySS (73 mV) and GSH/GSSG (100 mV) redox couples and increased CTNS mRNA levels by 1.9+/-0.2-fold (p<0.001). Conversely, a reduced cell environment associated with a GSH/GSSG reduction from -250.1+/-3.10 to -330.6+/-4.70 mV (p<0.001) and a Cys/CySS reduction from -167.0+/-11.30 to -240.0+/-8.17 mV (p<0.005) was associated with a 40% decrease in CTNS mRNA levels (p<0.05). By regression analysis, CTNS gene expression was correlated with intracellular Cys level and with Cys/CySS redox state.
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Affiliation(s)
- Francesco Bellomo
- Department of Nephrology and Urology, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy
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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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Figueiredo VC, Feksa LR, Wannmacher CMD. Cysteamine prevents inhibition of adenylate kinase caused by cystine in rat brain cortex. Metab Brain Dis 2009; 24:723-31. [PMID: 19437111 DOI: 10.1007/s11011-009-9141-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 04/14/2009] [Indexed: 10/20/2022]
Abstract
Cystinosis is a systemic genetic disease caused by a lysosomal transport deficiency accumulating cystine in the lysosomes of almost all tissues. Although tissue damage might depend on cystine accumulation, the mechanisms of tissue damage are still obscures. Adenylate kinase, along with creatine kinase, is responsible for the enzymatic phosphotransfer network, crucial for energy homeostasis. Taking into account that cystine is known to inhibit creatine kinase activity, the two enzymes have thiol groups, and the strong interaction between the two activities, our main objective was to investigate the effect of cystine on adenylate kinase activity in the brain cortex of Wistar rats. For the in vivo studies, the animals were injected twice a day with 1.6 micromol/g body weight of cystine dimethylester and/or 0.46 micromol/g body weight of cysteamine from the 25th to the 29th postpartum day and sacrificed after 12 h. Cystine inhibited the enzyme activity in vitro in a concentration dependent way, whereas cysteamine prevented the inhibition. Adenylate kinase activity was found diminished in the brain cortex of rats loaded with cystine dimethylester and co-administration of cysteamine prevented the diminution of the enzyme activity. Considering that adenylate kinase together with creatine kinase is crucial for energy homeostasis, the release of cystine from lysosomes with consequent enzymes inhibition could impair energy homeostasis, contributing to tissue damage in patients with cystinosis.
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Affiliation(s)
- Vandré Casagrande Figueiredo
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Rua Ramiro Barcelos 2600, Porto Alegre, RS, CEP 90.035-003, Brazil
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Besouw MTP, Levtchenko EN, Willemsen MAAP, Noordam K. Growth hormone producing prolactinoma in juvenile cystinosis: a simple coincidence? Pediatr Nephrol 2008; 23:307-10. [PMID: 17638022 PMCID: PMC2668588 DOI: 10.1007/s00467-007-0543-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 05/30/2007] [Accepted: 05/31/2007] [Indexed: 12/01/2022]
Abstract
Juvenile cystinosis was diagnosed in a patient who presented with severe headache attacks and photophobia. Treatment with oral cysteamine and topical cysteamine eye drops was started. One-and-a-half years later, he developed unilateral gynecomastia and elevated prolactin and growth hormone levels. A pituitary macroprolactinoma was discovered and successfully treated with the dopamine agonist cabergoline. Increased serum growth hormone levels were attributed to enhanced growth hormone production by the prolactinoma and somatostatin inhibition by cysteamine. Although the occurrence of prolactinoma in this patient could be a simple coincidence, it might also be a rare yet unrecognised complication of cystinosis.
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Affiliation(s)
- Martine T. P. Besouw
- Department of Pediatric Nephrology, University Medical Centre St Radboud, Nijmegen, The Netherlands
| | - Elena N. Levtchenko
- Department of Pediatric Nephrology, University Medical Centre St Radboud, Nijmegen, The Netherlands
- Geert Grooteplein 10, P.O. 9101, 6500 HB Nijmegen, The Netherlands
| | | | - Kees Noordam
- Department of Metabolic and Endocrine Disorders, University Medical Centre St Radboud, Nijmegen, The Netherlands
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Kalatzis V, Serratrice N, Hippert C, Payet O, Arndt C, Cazevieille C, Maurice T, Hamel C, Malecaze F, Antignac C, Müller A, Kremer EJ. The ocular anomalies in a cystinosis animal model mimic disease pathogenesis. Pediatr Res 2007; 62:156-62. [PMID: 17597652 DOI: 10.1203/pdr.0b013e31809fda89] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cystinosis is a lysosomal storage disorder characterized by abnormal accumulation of cystine, which forms crystals at high concentrations. The causative gene CTNS encodes cystinosin, the lysosomal cystine transporter. The eye is one of the first organs affected (corneal lesions and photophobia in the first and visual impairment in the second decade of life). We characterized the ocular anomalies of Ctns-/- mice to determine whether they mimic those of patients. The most dramatic cystine accumulation was seen in the iris, ciliary body, and cornea of Ctns-/- mice. Consistently, Ctns-/- mice had a low intraocular pressure (IOP) and seemed mildly photophobic. Retinal cystine levels were elevated but increased less dramatically with age. Consistently, the retina was intact and electroretinogram (ERG) profiles were normal in mice younger than 19 mo; beyond this age, retinal crystals and lesions appeared. Finally, the lens contained the lowest cystine levels and crystals were not seen. The temporospatial pattern of cystine accumulation in Ctns-/- mice parallels that of patients and validates the mice as a model for the ocular anomalies of cystinosis. This work is a prerequisite step to the testing of novel ocular cystine-depleting therapies.
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Wilmer MJ, Willems PH, Verkaart S, Visch HJ, de Graaf-Hess A, Blom HJ, Monnens LA, van den Heuvel LP, Levtchenko EN. Cystine dimethylester model of cystinosis: still reliable? Pediatr Res 2007; 62:151-5. [PMID: 17597653 DOI: 10.1203/pdr.0b013e31809fd9a7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The ability of cystine dimethylester (CDME) to load lysosomes with cystine has been used to establish the basic defect in cystinosis: defective cystine exodus from lysosomes. Using CDME loading, it has been postulated that cystine accumulation in cystinosis affects mitochondrial ATP production, resulting in defective renal tubular reabsorption. Recent studies in cystinotic fibroblasts, however, show normal adenosine triphosphate (ATP) generation capacity. To investigate the effect of CDME in more detail, mitochondrial ATP generation, reactive oxygen species production, and viability are compared in fibroblasts loaded with CDME with those of cystinotic cells with a defective cystine transporter. Intracellular cystine levels were comparable in fibroblasts loaded with CDME (1 mM, 30 min) and cystinotic fibroblasts. Intracellular ATP levels and mitochondrial ATP production were decreased in fibroblasts loaded with CDME, but normal in cystinotic fibroblasts. Superoxide production was increased with 300% after CDME loading, whereas no changes were observed in cystinotic fibroblasts. Exposure to CDME led to cell death in a time- and concentration-dependent manner. Our data demonstrate that CDME has a toxic effect on mitochondrial ATP production and cell viability. These effects are not observed in cystinotic cells, indicating that a more appropriate model is required for studying the pathogenesis of cystinosis.
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Affiliation(s)
- Martijn J Wilmer
- Laboratory of Pediatrics and Neurology, Radboud University Nijmegen Medical Centre, 6500 HB, Nijmegen, The Netherlands.
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Fidler MC, Barshop BA, Gangoiti JA, Deutsch R, Martin M, Schneider JA, Dohil R. Pharmacokinetics of cysteamine bitartrate following gastrointestinal infusion. Br J Clin Pharmacol 2007; 63:36-40. [PMID: 17229040 PMCID: PMC2000721 DOI: 10.1111/j.1365-2125.2006.02734.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIMS Although cysteamine was first used in the treatment of cystinosis in 1976 and approved by the FDA as cysteamine bitartrate (Cystagon) in 1994, surprisingly little pharmacological data are available for this compound. Cysteamine and its related drugs are currently being evaluated for the treatment of Huntington's and Parkinson's disease. The aim of te study was to understand the pharmacokinetics of cysteamine bitartrate following gastrointestinal infusion. METHOD Cysteamine bitartrate was delivered through a naso-enteric catheter into the stomach (n = 8), small intestine (n = 8) and caecum (n = 4) of normal subjects. Plasma cysteamine concentrations were determined using LC-MS/MS. RESULTS The rate and extent of drug absorption were assessed by comparing AUC(0, infinity), C(max) and t(max), among the gastrointestinal infusion sites. Total cysteamine exposure, expressed as area under the curve (AUC(0, infinity)) was greatest when the drug was infused into the small intestine (4331.3 +/- 1907.6 min x microM) followed by stomach (3901.9 +/- 1591.9 min x microM) and caecum (3141.4 +/- 1627.6 min x microM). Cysteamine infusion into the small intestine resulted in the most rapid rise to maximal plasma concentrations (t(max) = 21 +/- 0.56 min); t(max) was delayed to 50 +/- 26 min and 64 +/- 26 min after gastric and caecal infusion, respectively. The maximum cysteamine plasma concentration (C(max)) was reached after infusion of the drug into the small intestine (51 +/- 21 microM), which was higher than plasma C(max) concentrations after gastric (39 +/- 16 microM) and caecal infusion (23 +/- 15 microM). CONCLUSIONS The pharmacokinetic data generated help extend our understanding of cysteamine.
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Affiliation(s)
| | | | | | - Reena Deutsch
- Department of Family & Preventive Medicine, University of CaliforniaSan Diego, La Jolla, California, USA
| | | | | | - Ranjan Dohil
- Department of Family & Preventive Medicine, University of CaliforniaSan Diego, La Jolla, California, USA
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Fung AT, Fraser-Bell S, Ojaimi E, Sutton G. In vivo confocal microscopy and polarizing microscopy of the cornea in a patient with nephropathic cystinosis. Clin Exp Ophthalmol 2007; 35:292-3. [PMID: 17430525 DOI: 10.1111/j.1442-9071.2007.01467.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The clinicopathological and in vivo confocal microscopic characteristics of the corneas from a patient with infantile cystinosis is reported. Crystals were demonstrated in the epithelium and stroma of this patient.
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Tsilou E, Zhou M, Gahl W, Sieving PC, Chan CC. Ophthalmic manifestations and histopathology of infantile nephropathic cystinosis: report of a case and review of the literature. Surv Ophthalmol 2007; 52:97-105. [PMID: 17212992 PMCID: PMC1850966 DOI: 10.1016/j.survophthal.2006.10.006] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cystinosis is a rare autosomal recessive metabolic disorder characterized by the intracellular accumulation of cystine, the disulfide of the amino acid cysteine, in many organs and tissues. Infantile nephropathic cystinosis is the most severe phenotype. Corneal crystal accumulation and pigmentary retinopathy were originally the most commonly described ophthalmic manifestations, but successful kidney transplantation significantly changed the natural history of the disease. As cystinosis patients now live longer, long-term complications in extrarenal tissues, including the eye, have become apparent. A case of an adult patient with infantile nephropathic cystinosis is reported. He presented with many long-term ocular complications of cystinosis. After 4 years of follow-up, the patient died from sepsis. Pathology of the phthisical eyes demonstrated numerous electron-transparent polygonal spaces, bounded by single membrane, in corneal cells, retinal pigment epithelial cells, and even choroidal endothelial cells. The ophthalmic manifestations and pathology of infantile nephropathic cystinosis are discussed and reviewed in light of the current report and other cases in the literature.
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Affiliation(s)
- Ekaterini Tsilou
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Dohil R, Fidler M, Barshop BA, Gangoiti J, Deutsch R, Martin M, Schneider JA. Understanding intestinal cysteamine bitartrate absorption. J Pediatr 2006; 148:764-9. [PMID: 16769383 DOI: 10.1016/j.jpeds.2006.01.050] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 11/29/2005] [Accepted: 01/31/2006] [Indexed: 11/22/2022]
Abstract
OBJECTIVES To test the hypothesis that a controlled-release preparation of cysteamine, with fewer daily administrations, would improve the quality of life for patients with cystinosis. STUDY DESIGN A specifically designed nasoenteric tube was used to administer cysteamine directly into the stomach, small intestine (SI) and colon and serial plasma cysteamine, serum gastrin and leukocyte cystine levels were measured. RESULTS Eight control subjects (mean age 23.2 years) and 6 subjects with cystinosis (mean age 15.2 years) were studied. Cysteamine absorption (maximum concentration and area under the curve of the concentration-time gradient) was greater from the SI than stomach or cecum (P < .01). Leukocyte cystine depletion was greater after delivery of cysteamine into the SI than stomach or cecum; this effect was associated with the plasma cysteamine maximum concentration and area under the curve (P < .001 and < .02, respectively). Gastrin levels were not affected by site of drug delivery and were elevated only in patients with cystinosis with gastrointestinal symptoms. CONCLUSIONS The absorption of cysteamine and the effect of this agent on leukocyte cystine depletion are more profound after SI administration. Enteric-coated cysteamine, targeted for SI release, may require fewer daily dosages. Not all patients with cystinosis require acid-suppression therapy.
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Affiliation(s)
- Ranjan Dohil
- Department of Pediatrics, University of California, San Diego, La Jolla, California 92103-8450, USA.
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Laube GF, Shah V, Stewart VC, Hargreaves IP, Haq MR, Heales SJR, van't Hoff WG. Glutathione depletion and increased apoptosis rate in human cystinotic proximal tubular cells. Pediatr Nephrol 2006; 21:503-9. [PMID: 16508773 DOI: 10.1007/s00467-006-0005-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 09/26/2005] [Accepted: 09/28/2005] [Indexed: 12/17/2022]
Abstract
We have determined levels of glutathione (GSH), ATP, mitochondrial complex activity and apoptosis rate in proximal tubular cells (PTCs) exfoliated from urine in cystinotic (n=9) and control (n=9) children. Intracellular GSH was significantly depleted in cystinotic PTCs compared with controls (6.8 nmol GSH/mg protein vs 11.8 nmol GSH/mg protein; P<0.001), but there were no significant differences in mitochondrial complex activities or ATP levels under basal conditions. Cystinotic PTCs showed significantly increased apoptosis rate. After PTCs had been stressed by hypoxia, there was further depletion of GSH in cystinotic and control PTCs (2.4 nmol GSH/mg protein vs 7.2 nmol GSH/mg protein; P<0.001). Hypoxic stress led to increased complex I and complex IV activities in control but not in cystinotic PTCs. ATP levels were significantly reduced in cystinotic PTCs after hypoxic stress (12.2 nmol/mg protein vs 26.9 nmol/mg protein; P<0.001). GSH depletion occurs in this in vitro model of cystinotic PTCs, is exaggerated by hypoxic stress and may contribute to reduced ATP and failure to increase complex I/IV activities. Apoptotic rate is also increased, and these mechanisms may contribute to cellular dysfunction in cultured, human cystinotic PTCs.
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Affiliation(s)
- Guido F Laube
- Nephro-urology Unit, Institute of Child Health, University College London Medical School, London, UK.
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Schneider JA, Rosenbloom FM, Bradley KH, Seegmiller JE. Increased free-cystine content of fibroblasts cultured from patients with cystinosis. Biochem Biophys Res Commun 2006; 29:527-31. [PMID: 16496530 DOI: 10.1016/0006-291x(67)90516-5] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The presence of a significantly increased content of free-cystine in skin fibroblasts from both homozygotes and heterozygotes for cystinosis emphasizes the central role of cystine in this disease, even though the primary defect responsible for cystine accumulation is yet to be determined. The studies described in this communication provide evidence that cystine is compartmentalized in a subcellular location in cystinotic cells. In fact, the very growth of cystinotic fibroblasts in the presence more than 100 times the usual content of free-cystine is evidence that the accumulated cystine is not freely dispersed throughout the cell, since would otherwise inhibit many enzymes requiring free sulfhydryl groups for activity (Patrick, 1965). We have no evidence as to whether the cystine is located in a known subcellular organelle or in a previously unrecognized location. Skin fibroblasts may provide a convenient tool to pursue these questions.
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Affiliation(s)
- J A Schneider
- Section on Human Biochemical Genetics, National Institute of Arthritis and Metabolic Diseases, National Institutes of Health, Bethesda, Maryland, USA
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41
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Abstract
Cystinotic patients have been shown to excrete in their urine high levels of pyroglutamate, an intermediate metabolite of the adenosine triphosphate (ATP)-dependent gamma-glutamyl cycle, which is responsible for glutathione (GSH) synthesis. Human fibroblasts were used to study the mechanisms leading to pyroglutamate accumulation in nephropathic cystinosis (NC). We show that inhibition of ATP synthesis caused a marked intracellular accumulation of pyroglutamate, reflecting decreased GSH synthesis. Despite similar degrees of ATP depletion, pyroglutamate increased more in cystinotic fibroblasts than in controls, while GSH decreased to lower levels. In addition, cystinotic cells exposed to oxidative stress (hydrogen peroxide) were unable to increase their GSH concentration above baseline. These results could not be attributed to differences in mitochondrial oxidative activity or to increased apoptotic cell death. Together, these results support the hypothesis that cysteine derived from lysosomal cystine efflux limits the activity of the gamma-glutamyl cycle and GSH synthesis.
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Affiliation(s)
- Liliana Mannucci
- Department of Nephrology and Urology, Bambino Gesù Children's Hospital and Research Institute, Rome, Italy
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42
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Levtchenko EN, Wilmer MJG, Janssen AJM, Koenderink JB, Visch HJ, Willems PHGM, de Graaf-Hess A, Blom HJ, van den Heuvel LP, Monnens LA. Decreased intracellular ATP content and intact mitochondrial energy generating capacity in human cystinotic fibroblasts. Pediatr Res 2006; 59:287-92. [PMID: 16439594 DOI: 10.1203/01.pdr.0000196334.46940.54] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cystinosis is an autosomal recessive lysosomal storage disorder caused by a defect in the lysosomal cystine carrier cystinosin. Cystinosis is the most common cause of inherited Fanconi syndrome leading to renal failure, in which the pathogenesis is still enigmatic. Based on studies of proximal tubules loaded with cystine dimethyl ester (CDME), altered mitochondrial adenosine triphosphate (ATP) production was proposed to be an underlying pathologic mechanism. Thus far, however, experimental evidence supporting this hypothesis in humans is lacking. In this study, energy metabolism was extensively investigated in primary fibroblasts derived from eight healthy subjects and eight patients with cystinosis. Patient's fibroblasts accumulated marked amounts of cystine and displayed a significant decrease in intracellular ATP content. Remarkably, overall energy-generating capacity, activity of respiratory chain complexes, ouabain-dependent rubidium uptake reflecting Na,K-ATPase activity, and bradykinin-stimulated mitochondrial ATP production were all normal in these cells. In conclusion, the data presented demonstrate that mitochondrial energy-generating capacity and Na,K-ATPase activity are intact in cultured cystinotic fibroblasts, thus questioning the idea of altered mitochondrial ATP synthesis as a keystone for the pathogenesis of cystinosis.
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Affiliation(s)
- Elena N Levtchenko
- Department of Pediatrics, Radboud University Nijmegen Medical Center, The Netherlands.
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43
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Zachwieja J. [Cystinosis--an orphan disease. Pathogenesis and current treatment]. Przegl Lek 2006; 63 Suppl 3:29-31. [PMID: 16898482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Cystinosis belongs to, so called, orphan diseases. It is an autosomal recessive lysosomal storage disease caused by defective transport of the amino acid cystine out of lysosomes. The stored cystine is poorly soluble and crystallizes within the lysosomes of many cell types, leading to widespread tissue and organ damage. Patients with the infantile nephropathic form of cystinosis (the most common and the most severe) develop symptoms early on in life and renal failure by late childhood. The current opinion about pathogenesis and treatment of the disease is described.
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Affiliation(s)
- Jacek Zachwieja
- Klinika Kardiologii i Nefrologii Dzieciecej, Instytut Pediatrii, Akademia Medyczna, im K Marcinkowskiego w Poznaniu.
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Levtchenko EN, van Dael CM, de Graaf-Hess AC, Wilmer MJG, van den Heuvel LP, Monnens LA, Blom HJ. Strict cysteamine dose regimen is required to prevent nocturnal cystine accumulation in cystinosis. Pediatr Nephrol 2006; 21:110-3. [PMID: 16252107 DOI: 10.1007/s00467-005-2052-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 07/08/2005] [Accepted: 07/08/2005] [Indexed: 11/24/2022]
Abstract
Cystinosis is an autosomal recessive disorder, caused by mutations in the lysosomal cystine carrier cystinosin, encoded by the CTNS gene. The disease generally manifests with Fanconi syndrome during the first year of life and progresses towards end stage renal disease before the age of 10 years. Cysteamine depletes intralysosomal cystine content, postpones the deterioration of renal function and the occurrence of extra-renal organ damage. Based on the pharmacokinetic data, patients with cystinosis are advised to use cysteamine every 6 h. The aim of this study was (1) to evaluate the cysteamine dose regimen in Dutch patients with cystinosis and (2) to determine morning polymorphonuclear (PMN) leukocyte cystine content 6 h vs 9 h after the last evening cysteamine dose. Only 5/22 of Dutch cystinosis patients ingested cysteamine every 6 h. Morning (8 a.m.) PMN cystine content in 11 examined patients was elevated 9 h after 12.5-15 mg/kg evening cysteamine dose compared to the value 6 h after the ingestion of the same dose (0.73+/-0.81 nmol vs 0.44+/-0.52 nmol cystine/mg protein, p =0.02). In conclusion, only the minority of Dutch cystinosis patients follows the recommended strict cysteamine dose regimen. We provide evidence that cysteamine has to be administered every 6 h, including the night, as it has much better effect for maintaining low PMN cystine levels.
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Affiliation(s)
- Elena N Levtchenko
- Department of Paediatric Nephrology, Radboud University Nijmegen Medical Centre, P.O. 9101, 6500 HB, Nijmegen, The Netherlands.
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Wilmer MJG, de Graaf-Hess A, Blom HJ, Dijkman HBPM, Monnens LA, van den Heuvel LP, Levtchenko EN. Elevated oxidized glutathione in cystinotic proximal tubular epithelial cells. Biochem Biophys Res Commun 2005; 337:610-4. [PMID: 16202976 DOI: 10.1016/j.bbrc.2005.09.094] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Accepted: 09/09/2005] [Indexed: 11/17/2022]
Abstract
Cystinosis, the most frequent cause of inborn Fanconi syndrome, is characterized by the lysosomal cystine accumulation, caused by mutations in the CTNS gene. To elucidate the pathogenesis of cystinosis, we cultured proximal tubular cells from urine of cystinotic patients (n = 9) and healthy controls (n = 9), followed by immortalization with human papilloma virus (HPV E6/E7). Obtained cell lines displayed basolateral polarization, alkaline phosphatase activity, and presence of aminopeptidase N (CD-13) and megalin, confirming their proximal tubular origin. Cystinotic cell lines exhibited elevated cystine levels (0.86 +/- 0.95 nmol/mg versus 0.09 +/- 0.01 nmol/mg protein in controls, p = 0.03). Oxidized glutathione was elevated in cystinotic cells (1.16 +/- 0.83 nmol/mg versus 0.29 +/- 0.18 nmol/mg protein, p = 0.04), while total glutathione, free cysteine, and ATP contents were normal in these cells. In conclusion, elevated oxidized glutathione in cystinotic proximal tubular epithelial cell lines suggests increased oxidative stress, which may contribute to tubular dysfunction in cystinosis.
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Affiliation(s)
- Martijn J G Wilmer
- Laboratory of Pediatrics and Neurology, Radboud University Nijmegen Medical Centre, The Netherlands
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Levtchenko E, de Graaf-Hess A, Wilmer M, van den Heuvel L, Monnens L, Blom H. Altered status of glutathione and its metabolites in cystinotic cells. Nephrol Dial Transplant 2005; 20:1828-32. [PMID: 15956064 DOI: 10.1093/ndt/gfh932] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Cystinosis is an autosomal recessive disorder, caused by mutations of the lysosomal cystine carrier cystinosin, encoded by the CTNS gene (17p13). The concomitant intralysosomal cystine accumulation leads to multi-organ damage, with kidneys being the first affected. Altered mitochondrial oxidative phosphorylation has been demonstrated in animal proximal tubules loaded with cystine dimethyl ester, mimicking cystine accumulation in cystinosis, but has not been confirmed in cells of patients with cystinosis. Furthermore, the link between cystine accumulation and mitochondrial damage is also missing. We hypothesized that cytosolic cysteine deficiency resulting in intracellular glutathione (GSH) shortage might be involved in cellular dysfunction in cystinosis. METHODS Components of the gamma-glutamyl cycle were measured in cultured skin fibroblasts (n = 9) and polymorphonuclear (PMN) leukocytes (n = 15) derived from patients with cystinosis and compared with the values in cultured fibroblasts (n = 9) and PMN cells (n = 18) of healthy controls. RESULTS Cystine content in cystinotic fibroblasts and PMN cells was significantly elevated compared with the controls, consistent with the lysosomal cystine accumulation in these cells. Although no reduction of total intracellular GSH content was found in cystinotic cells, it inversely correlated with cystine levels. Furthermore, GSH disulfide (GSSG) was elevated in cystinotic cells, resulting in an increased GSSG/total GSH (%) ratio. No relationship between intracellular cystine and GSH was found in control fibroblasts and PMN cells. CONCLUSION An elevated GSSG/total GSH (%) ratio might indicate increased oxidative stress present in cystinotic cells. Inverse correlation between cystine accumulation and intracellular GSH content indicates that under stress conditions such as intensive energy demand or increased oxidative insult, cystinotic cells may be more prone to GSH depletion.
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Affiliation(s)
- Elena Levtchenko
- Department of Paediatric Nephrology, Radboud University Nijmegen Medical Centre, PO 9101, 6500 HB Nijmegen, The Netherlands.
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Chol M, Nevo N, Cherqui S, Antignac C, Rustin P. Glutathione precursors replenish decreased glutathione pool in cystinotic cell lines. Biochem Biophys Res Commun 2004; 324:231-5. [PMID: 15465007 DOI: 10.1016/j.bbrc.2004.09.033] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2004] [Indexed: 12/13/2022]
Abstract
Cystinosis is an inherited disorder due to mutations in the CTNS gene which encodes cystinosin, a lysosomal transmembrane protein involved in cystine export to the cytosol. Both accumulation of cystine in the lysosome and decreased cystine in the cytosol may participate in the pathogenic mechanism underlying the disease. We observed that cystinotic cell lines have moderate decrease of glutathione content during exponential growth phase. This resulted in increased solicitation of oxidative defences of the cell denoted by concurrent superoxide dismutase induction, although without major oxidative insult under our experimental conditions. Finally, decreased glutathione content in cystinotic cell lines could be counterbalanced by a series of exogenous precursors of cysteine, denoting that lysosomal cystine export is a natural source of cellular cysteine in the studied cell lines.
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Affiliation(s)
- Marie Chol
- INSERM U574, Néphropathies Héréditaires et Rein en Développement, Hôpital Necker-Enfants Malades, rue de Sèvres, 75015 Paris, France
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48
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49
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Rosa TG, de Souza Wyse AT, Wajner M, Wannmacher CMD. Cysteamine prevents and reverses the inhibition of pyruvate kinase activity caused by cystine in rat heart. Biochim Biophys Acta Mol Basis Dis 2004; 1689:114-9. [PMID: 15196592 DOI: 10.1016/j.bbadis.2004.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2003] [Revised: 02/24/2004] [Accepted: 02/27/2004] [Indexed: 10/26/2022]
Abstract
Cystinosis is a disorder associated with excessive lysosomal cystine accumulation secondary to defective cystine efflux. Patients affected by this disease develop a variable degree of symptoms depending on the involved tissues. Accumulation of cystine in myocardium may lead to heart failure. However, the mechanisms by which cystine is toxic to the tissues are not fully understood. Considering that thiolic enzymes like pyruvate kinase (PK) may be altered by disulfides like cystine, the main objective of the present study was to investigate the effect of cystine on PK activity in the heart of developing rats. We performed kinetic studies and investigated the effects of reduced glutathione (GSH), a biologically occurring thiol groups protector, and cysteamine, the drug used for cystinosis treatment, on the enzyme activity. We observed that cystine inhibited the enzyme activity non-competitively in a dose- and time-dependent way. We also observed that GSH and cysteamine fully prevented and reversed the inhibition caused by cystine, suggesting that cystine inhibits PK activity by oxidation of the sulfhydryl groups of the enzyme. Although there is no definite proof of cystine within cytoplasm, there is indirect proof t it is able to escape lysosomes and come in contact with PK. Considering that cysteamine is used in patients with cystinosis because it causes parenchymal organ cystine depletion, the present data provide a possible new effect for this drug.
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Affiliation(s)
- Tatiana Galetto Rosa
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Rua Ramiro Barcelos 2600-Anexo, CEP 90.035-003, Porto Alegre, RS, Brazil
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50
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Abstract
This paper gives an overview of the two sialic acid storage disorders, Salla disease and infantile sialic acid storage disease, and the related disorders cystinosis, sialuria, sialidosis, and galactosialidosis. Sialic acid storage disease and cystinosis are models for a deficient lysosomal transport of monosaccharides and amino acids, respectively. Several gene mutations leading to the production of the faulty membrane proteins sialin and cystinosin have been identified in recent years. Knowledge of the underlying pathophysiology is a prerequisite for future research projects, which will focus on the expression of the disease genes in living systems and the physical characterization of these proteins by X-ray crystallography and nuclear magnetic resonance spectroscopy.
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Affiliation(s)
- E M Strehle
- Northern Health Centre, London WC1E 7HX, England, UK.
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