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Matalonga L, Gort L, Ribes A. Small molecules as therapeutic agents for inborn errors of metabolism. J Inherit Metab Dis 2017; 40:177-193. [PMID: 27966099 DOI: 10.1007/s10545-016-0005-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 01/03/2023]
Abstract
Most inborn errors of metabolism (IEM) remain without effective treatment mainly due to the incapacity of conventional therapeutic approaches to target the neurological symptomatology and to ameliorate the multisystemic involvement frequently observed in these patients. However, in recent years, the therapeutic use of small molecules has emerged as a promising approach for treating this heterogeneous group of disorders. In this review, we focus on the use of therapeutically active small molecules to treat IEM, including readthrough agents, pharmacological chaperones, proteostasis regulators, substrate inhibitors, and autophagy inducers. The small molecules reviewed herein act at different cellular levels, and this knowledge provides new tools to set up innovative treatment approaches for particular IEM. We review the molecular mechanism underlying therapeutic properties of small molecules, methodologies used to screen for these compounds, and their applicability in preclinical and clinical practice.
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Affiliation(s)
- Leslie Matalonga
- Secció Errors Congènits del Metabolisme-IBC. Servei de Bioquímica i Genètica Molecular, Hospital Clínic, CIBERER-U737; IDIBAPS, C/ Mejía Lequerica s/n, 08028, Barcelona, Spain.
| | - Laura Gort
- Secció Errors Congènits del Metabolisme-IBC. Servei de Bioquímica i Genètica Molecular, Hospital Clínic, CIBERER-U737; IDIBAPS, C/ Mejía Lequerica s/n, 08028, Barcelona, Spain
| | - Antonia Ribes
- Secció Errors Congènits del Metabolisme-IBC. Servei de Bioquímica i Genètica Molecular, Hospital Clínic, CIBERER-U737; IDIBAPS, C/ Mejía Lequerica s/n, 08028, Barcelona, Spain
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52
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Stütz AE, Wrodnigg TM. Carbohydrate-Processing Enzymes of the Lysosome: Diseases Caused by Misfolded Mutants and Sugar Mimetics as Correcting Pharmacological Chaperones. Adv Carbohydr Chem Biochem 2016; 73:225-302. [PMID: 27816107 DOI: 10.1016/bs.accb.2016.08.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Lysosomal storage diseases are hereditary disorders caused by mutations on genes encoding for one of the more than fifty lysosomal enzymes involved in the highly ordered degradation cascades of glycans, glycoconjugates, and other complex biomolecules in the lysosome. Several of these metabolic disorders are associated with the absence or the lack of activity of carbohydrate-processing enzymes in this cell compartment. In a recently introduced therapy concept, for susceptible mutants, small substrate-related molecules (so-called pharmacological chaperones), such as reversible inhibitors of these enzymes, may serve as templates for the correct folding and transport of the respective protein mutant, thus improving its concentration and, consequently, its enzymatic activity in the lysosome. Carbohydrate-processing enzymes in the lysosome, related lysosomal diseases, and the scope and limitations of reported reversible inhibitors as pharmacological chaperones are discussed with a view to possibly extending and improving research efforts in this area of orphan diseases.
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Affiliation(s)
- Arnold E Stütz
- Glycogroup, Institute of Organic Chemistry, Graz University of Technology, Graz, Austria
| | - Tanja M Wrodnigg
- Glycogroup, Institute of Organic Chemistry, Graz University of Technology, Graz, Austria
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53
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Dersh D, Iwamoto Y, Argon Y. Tay-Sachs disease mutations in HEXA target the α chain of hexosaminidase A to endoplasmic reticulum-associated degradation. Mol Biol Cell 2016; 27:3813-3827. [PMID: 27682588 PMCID: PMC5170605 DOI: 10.1091/mbc.e16-01-0012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 09/15/2016] [Accepted: 09/22/2016] [Indexed: 12/29/2022] Open
Abstract
In Tay–Sachs disease, mutations in HEXA can lead to aberrant α subunits of the HexA enzyme. Two such mutants have folding defects and are cleared by endoplasmic reticulum-associated degradation. Toward the pursuit of therapeutic treatments, it was found that manipulating endoplasmic reticulum quality control can impair mutant α degradation and improve cellular Hex activity. Loss of function of the enzyme β-hexosaminidase A (HexA) causes the lysosomal storage disorder Tay–Sachs disease (TSD). It has been proposed that mutations in the α chain of HexA can impair folding, enzyme assembly, and/or trafficking, yet there is surprisingly little known about the mechanisms of these potential routes of pathogenesis. We therefore investigated the biosynthesis and trafficking of TSD-associated HexA α mutants, seeking to identify relevant cellular quality control mechanisms. The α mutants E482K and G269S are defective in enzymatic activity, unprocessed by lysosomal proteases, and exhibit altered folding pathways compared with wild-type α. E482K is more severely misfolded than G269S, as observed by its aggregation and inability to associate with the HexA β chain. Importantly, both mutants are retrotranslocated from the endoplasmic reticulum (ER) to the cytosol and are degraded by the proteasome, indicating that they are cleared via ER-associated degradation (ERAD). Leveraging these discoveries, we observed that manipulating the cellular folding environment or ERAD pathways can alter the kinetics of mutant α degradation. Additionally, growth of patient fibroblasts at a permissive temperature or with chemical chaperones increases cellular Hex activity by improving mutant α folding. Therefore modulation of the ER quality control systems may be a potential therapeutic route for improving some forms of TSD.
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Affiliation(s)
- Devin Dersh
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104
| | - Yuichiro Iwamoto
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104
| | - Yair Argon
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and University of Pennsylvania, Philadelphia, PA 19104
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54
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Tkachyova I, Fan X, LamHonWah AM, Fedyshyn B, Tein I, Mahuran DJ, Schulze A. NDST1 Preferred Promoter Confirmation and Identification of Corresponding Transcriptional Inhibitors as Substrate Reduction Agents for Multiple Mucopolysaccharidosis Disorders. PLoS One 2016; 11:e0162145. [PMID: 27657498 PMCID: PMC5033324 DOI: 10.1371/journal.pone.0162145] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 08/17/2016] [Indexed: 01/25/2023] Open
Abstract
The stepwise degradation of glycosaminoglycans (GAGs) is accomplished by twelve lysosomal enzymes. Deficiency in any of these enzymes will result in the accumulation of the intermediate substrates on the pathway to the complete turnover of GAGs. The accumulation of these undegraded substrates in almost any tissue is a hallmark of all Mucopolysaccharidoses (MPS). Present therapeutics based on enzyme replacement therapy and bone marrow transplantation have low effectiveness for the treatment of MPS with neurological complications since enzymes used in these therapies are unable to cross the blood brain barrier. Small molecule-based approaches are more promising in addressing neurological manifestations. In this report we identify a target for developing a substrate reduction therapy (SRT) for six MPS resulting from the abnormal degradation of heparan sulfate (HS). Using the minimal promoter of NDST1, one of the first modifying enzymes of HS precursors, we established a luciferase based reporter gene assay capable of identifying small molecules that could potentially reduce HS maturation and therefore lessen HS accumulation in certain MPS. From the screen of 1,200 compounds comprising the Prestwick Chemical library we identified SAHA, a histone deacetylase inhibitor, as the drug that produced the highest inhibitory effects in the reporter assay. More importantly SAHA treated fibroblasts expressed lower levels of endogenous NDST1 and accumulated less 35S GAGs in patient cells. Thus, by using our simple reporter gene assay we have demonstrated that by inhibiting the transcription of NDST1 with small molecules, identified by high throughput screening, we can also reduce the level of sulfated HS substrate in MPS patient cells, potentially leading to SRT.
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Affiliation(s)
- Ilona Tkachyova
- Genetics and Genome Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Xiaolian Fan
- Genetics and Genome Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Anne-Marie LamHonWah
- Genetics and Genome Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Bohdana Fedyshyn
- Genetics and Genome Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ingrid Tein
- Genetics and Genome Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Don J. Mahuran
- Genetics and Genome Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Andreas Schulze
- Genetics and Genome Biology, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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55
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Alteen M, Oehler V, Nemčovičová I, Wilson IB, Vocadlo DJ, Gloster TM. Mechanism of Human Nucleocytoplasmic Hexosaminidase D. Biochemistry 2016; 55:2735-47. [PMID: 27149221 PMCID: PMC4878814 DOI: 10.1021/acs.biochem.5b01285] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 04/13/2016] [Indexed: 12/23/2022]
Abstract
Mammalian β-hexosaminidases have been shown to play essential roles in cellular physiology and health. These enzymes are responsible for the cleavage of the monosaccharides N-acetylglucosamine (GlcNAc) and N-acetylgalactosamine (GalNAc) from cellular substrates. One of these β-hexosaminidases, hexosaminidase D (HexD), encoded by the HEXDC gene, has received little attention. No mechanistic studies have focused on the role of this unusual nucleocytoplasmically localized β-hexosaminidase, and its cellular function remains unknown. Using a series of kinetic and mechanistic investigations into HexD, we define the precise catalytic mechanism of this enzyme and establish the identities of key enzymic residues. The preparation of synthetic aryl N-acetylgalactosaminide substrates for HexD in combination with measurements of kinetic parameters for wild-type and mutant enzymes, linear free energy analyses of the enzyme-catalyzed hydrolysis of these substrates, evaluation of the reaction by nuclear magnetic resonance, and inhibition studies collectively reveal the detailed mechanism of action employed by HexD. HexD is a retaining glycosidase that operates using a substrate-assisted catalytic mechanism, has a preference for galactosaminide over glucosaminide substrates, and shows a pH optimum in its second-order rate constant at pH 6.5-7.0. The catalytically important residues are Asp148 and Glu149, with Glu149 serving as the general acid/base residue and Asp148 as the polarizing residue. HexD is inhibited by Gal-NAG-thiazoline (Ki = 420 nM). The fundamental insights gained from this study will aid in the development of potent and selective probes for HexD, which will serve as useful tools to improve our understanding of the physiological role played by this unusual enzyme.
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Affiliation(s)
- Matthew
G. Alteen
- Department
of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A
1S6, Canada
- Biomedical
Sciences Research Complex, University of
St Andrews, North Haugh,
St Andrews, Fife KY16 9ST, U.K.
| | - Verena Oehler
- Biomedical
Sciences Research Complex, University of
St Andrews, North Haugh,
St Andrews, Fife KY16 9ST, U.K.
| | - Ivana Nemčovičová
- Department
für Chemie, Universität für
Bodenkultur, Muthgasse
18, A-1190 Wien, Austria
| | - Iain B.
H. Wilson
- Department
für Chemie, Universität für
Bodenkultur, Muthgasse
18, A-1190 Wien, Austria
| | - David J. Vocadlo
- Department
of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A
1S6, Canada
| | - Tracey M. Gloster
- Biomedical
Sciences Research Complex, University of
St Andrews, North Haugh,
St Andrews, Fife KY16 9ST, U.K.
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Schultz ML, Krus KL, Lieberman AP. Lysosome and endoplasmic reticulum quality control pathways in Niemann-Pick type C disease. Brain Res 2016; 1649:181-188. [PMID: 27026653 DOI: 10.1016/j.brainres.2016.03.035] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/17/2016] [Accepted: 03/24/2016] [Indexed: 12/13/2022]
Abstract
Lysosomal storage diseases result from inherited deficiencies of lysosomal hydrolytic activities or lipid transport. Collectively, these disorders are a common cause of morbidity in the pediatric population and are often associated with severe neurodegeneration. Among this group of diseases is Niemann-Pick type C, an autosomal recessive disorder of lipid trafficking that causes cognitive impairment, ataxia and death, most often in childhood. Here, we review the current knowledge of disease pathogenesis, with particular focus on insights gleaned from genetics and the study of model systems. Critical advances in understanding mechanisms that regulate intracellular cholesterol trafficking have emerged from this work and are highlighted. We review effects of disease-causing mutations on quality control pathways involving the lysosome and endoplasmic reticulum, and discuss how they function to clear the most common mutant protein found in Niemann-Pick type C patients, NPC1-I1061T. Finally, we summarize insights into the mechanisms that degrade misfolded transmembrane proteins in the endoplasmic reticulum and how manipulating these quality control pathways may lead to the identification of novel targets for disease-modifying therapies. This article is part of a Special Issue entitled SI:Autophagy.
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Affiliation(s)
- Mark L Schultz
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Kelsey L Krus
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Andrew P Lieberman
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
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Construction of a hybrid β-hexosaminidase subunit capable of forming stable homodimers that hydrolyze GM2 ganglioside in vivo. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2016; 3:15057. [PMID: 26966698 PMCID: PMC4774620 DOI: 10.1038/mtm.2015.57] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 12/17/2015] [Indexed: 02/07/2023]
Abstract
Tay-Sachs or Sandhoff disease result from mutations in either the evolutionarily related HEXA or HEXB genes encoding respectively, the α- or β-subunits of β-hexosaminidase A (HexA). Of the three Hex isozymes, only HexA can interact with its cofactor, the GM2 activator protein (GM2AP), and hydrolyze GM2 ganglioside. A major impediment to establishing gene or enzyme replacement therapy based on HexA is the need to synthesize both subunits. Thus, we combined the critical features of both α- and β-subunits into a single hybrid µ-subunit that contains the α-subunit active site, the stable β-subunit interface and unique areas in each subunit needed to interact with GM2AP. To facilitate intracellular analysis and the purification of the µ-homodimer (HexM), CRISPR-based genome editing was used to disrupt the HEXA and HEXB genes in a Human Embryonic Kidney 293 cell line stably expressing the µ-subunit. In association with GM2AP, HexM was shown to hydrolyze a fluorescent GM2 ganglioside derivative both in cellulo and in vitro. Gene transfer studies in both Tay-Sachs and Sandhoff mouse models demonstrated that HexM expression reduced brain GM2 ganglioside levels.
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58
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Hossain MA, Higaki K, Shinpo M, Nanba E, Suzuki Y, Ozono K, Sakai N. Chemical chaperone treatment for galactosialidosis: Effect of NOEV on β-galactosidase activities in fibroblasts. Brain Dev 2016; 38:175-80. [PMID: 26259553 DOI: 10.1016/j.braindev.2015.07.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 07/14/2015] [Accepted: 07/24/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Galactosialidosis is a rare lysosomal storage disease caused by a combined deficiency of GM1 β-galactosidase (β-gal) and neuraminidase secondary to a defect of a lysosomal enzyme protective protein/cathepsin A (PPCA) and mutation in CTSA gene. Three subtypes are recognized: early infantile, late infantile, and juvenile/adult. There is no specific therapy for patients with galactosialidosis at this time. OBJECTIVES The aim of this study was to determine the chaperone effect of N-octyl-4-epi-β-valienamine (NOEV) on β-gal proteins in skin fibroblasts of PPCA-deficit patients. METHODS β-Gal and neuraminidase activities were measured for the diagnosis of the patients with galactosialidosis. Western blotting for PPCA protein and direct sequencing for CTSA gene were performed. Cultured skin fibroblast were treated with NOEV. RESULTS We report four novel patients with galactosialidosis: one had the early infantile form and the other three had the juvenile/adult form. We found that NOEV stabilized β-gal activity in lysate from cultured skin fibroblasts from these patients. Treatment with NOEV significantly enhanced β-gal activity in cultured skin fibroblasts in the absence of PPCA. CONCLUSIONS Our results indicate the possibility that NOEV chaperone therapy might have a beneficial effect, at least in part, for patients with galactosialidosis.
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Affiliation(s)
- Mohammad Arif Hossain
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Katsumi Higaki
- Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Yonago, Japan
| | - Michiko Shinpo
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Eiji Nanba
- Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Yonago, Japan
| | | | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Norio Sakai
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
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Personalized Pharmacoperones for Lysosomal Storage Disorder: Approach for Next-Generation Treatment. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 102:225-65. [PMID: 26827607 DOI: 10.1016/bs.apcsb.2015.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lysosomal storage disorders (LSDs) are a collection of inborn errors of metabolic disorders affected by mutations in lysosome functional genes, commonly acid hydrolases. From the past decades, many approaches like enzyme replacement therapy, substrate reduction therapy are followed to treat these conditions. However, all these approaches have their own limitations. Proof-of-concept studies on pharmacological chaperone therapy (PCT) is now transformed into clinical practice to treat LSDs. Furthermore, it is narrowed with individuals to chaperone sensitive, specific mutations. Hence, personalizing the PCT will be a new direction to combat LSDs. In this review, we have discussed the available clinical strategies and pointed the light on how pharmacological chaperones can be personalized and hopeful to be a next-generation approach to address LSDs.
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Efficient stereoselective synthesis of 2-acetamido-1,2-dideoxyallonojirimycin (DAJNAc) and sp(2)-iminosugar conjugates: Novel hexosaminidase inhibitors with discrimination capabilities between the mature and precursor forms of the enzyme. Eur J Med Chem 2015; 121:926-938. [PMID: 26564401 DOI: 10.1016/j.ejmech.2015.10.038] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 10/07/2015] [Accepted: 10/21/2015] [Indexed: 11/21/2022]
Abstract
Due to their capacity to inhibit hexosaminidases, 2-acetamido-1,2-dideoxy-iminosugars have been widely studied as potential therapeutic agents for various diseases. An efficient stereoselective synthesis of 2-acetamido-1,2-dideoxyallonojirimycin (DAJNAc), the most potent inhibitor of human placenta β-N-acetylglucosaminidase (β-hexosaminidase) among the epimeric series, is here described. This novel procedure can be easily scaled up, providing enough material for structural modifications and further biological tests. Thus, two series of sp(2)-iminosugar conjugates derived from DAJNAc have been prepared, namely monocyclic DAJNAc-thioureas and bicyclic 2-iminothiazolidines, and their glycosidase inhibitory activity evaluated. The data evidence the utmost importance of developing diversity-oriented synthetic strategies allowing optimization of electrostatic and hydrophobic interactions to achieve high inhibitory potencies and selectivities among isoenzymes. Notably, strong differences in the inhibition potency of the compounds towards β-hexosaminidase from human placenta (mature) or cultured fibroblasts (precursor form) were encountered. The ensemble of data suggests that the ratio between them, and not the inhibition potency towards the placenta enzyme, is a good indication of the chaperoning potential of TaySachs disease-associated mutant hexosaminidase.
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Hossain MA, Higaki K, Saito S, Ohno K, Sakuraba H, Nanba E, Suzuki Y, Ozono K, Sakai N. Chaperone therapy for Krabbe disease: potential for late-onset GALC mutations. J Hum Genet 2015; 60:539-45. [PMID: 26108143 DOI: 10.1038/jhg.2015.61] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 02/27/2015] [Accepted: 04/08/2015] [Indexed: 01/24/2023]
Abstract
Krabbe disease is an autosomal recessive leukodystrophy caused by a deficiency of the galactocerebrosidase (GALC) enzyme. Hematopoietic stem cells transplantation is the only available treatment option for pre-symptomatic patients. We have previously reported the chaperone effect of N-octyl-4-epi-β-valienamine (NOEV) on mutant GM1 β-galactosidase proteins, and in a murine GM1-gangliosidosis model. In this study, we examined its chaperone effect on mutant GALC proteins. We found that NOEV strongly inhibited GALC activity in cell lysates of GALC-transfected COS1 cells. In vitro NOEV treatment stabilized GALC activity under heat denaturation conditions. We also examined the effect of NOEV on cultured COS1 cells expressing mutant GALC activity and human skin fibroblasts from Krabbe disease patients: NOEV significantly increased the enzyme activity of mutants of late-onset forms. Moreover, we confirmed that NOEV could enhance the maturation of GALC precursor to its mature active form. Model structural analysis showed NOEV binds to the active site of human GALC protein. These results, for the first time, provide clear evidence that NOEV is a chaperone with promising potential for patients with Krabbe disease resulting from the late-onset mutations.
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Affiliation(s)
- Mohammad Arif Hossain
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Katsumi Higaki
- Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Yonago, Japan
| | - Seiji Saito
- Department of Medical Management and Informatics, Hokkaido Information University, Hokkaido, Japan
| | - Kazuki Ohno
- NPO for the Promotion of Research on Intellectual Property Tokyo, Tokyo, Japan
| | - Hitoshi Sakuraba
- Department of Clinical Genetics, Meiji Pharmaceutical University, Tokyo, Japan
| | - Eiji Nanba
- Division of Functional Genomics, Research Center for Bioscience and Technology, Tottori University, Yonago, Japan
| | | | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Norio Sakai
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
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Tropak MB, Zhang J, Yonekawa S, Rigat BA, Aulakh VS, Smith MR, Hwang HJ, Ciufolini MA, Mahuran DJ. Pyrimethamine Derivatives: Insight into Binding Mechanism and Improved Enhancement of Mutant β-N-acetylhexosaminidase Activity. J Med Chem 2015; 58:4483-93. [PMID: 25984755 DOI: 10.1021/jm5017895] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In order to identify structural features of pyrimethamine (5-(4-chlorophenyl)-6-ethylpyrimidine-2,4-diamine) that contribute to its inhibitory activity (IC50 value) and chaperoning efficacy toward β-N-acetylhexosaminidase, derivatives of the compound were synthesized that differ at the positions bearing the amino, ethyl, and chloro groups. Whereas the amino groups proved to be critical to its inhibitory activity, a variety of substitutions at the chloro position only increased its IC50 by 2-3-fold. Replacing the ethyl group at the 6-position with butyl or methyl groups increased IC50 more than 10-fold. Surprisingly, despite its higher IC50, a derivative lacking the chlorine atom in the para-position was found to enhance enzyme activity in live patient cells a further 25% at concentrations >100 μM, while showing less toxicity. These findings demonstrate the importance of the phenyl group in modulating the chaperoning efficacy and toxicity profile of the derivatives.
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Affiliation(s)
- Michael B Tropak
- †Genetics and Genome Biology, SickKids, PGCRL 686 Bay Street, Toronto, Ontario M5G 0A4, Canada
| | - Jianmin Zhang
- ‡Department of Chemistry, University of British Columbia, 2036 Main Mall Vancouver, British Columbia V6T 1Z1, Canada
| | - Sayuri Yonekawa
- †Genetics and Genome Biology, SickKids, PGCRL 686 Bay Street, Toronto, Ontario M5G 0A4, Canada
| | - Brigitte A Rigat
- †Genetics and Genome Biology, SickKids, PGCRL 686 Bay Street, Toronto, Ontario M5G 0A4, Canada
| | - Virender S Aulakh
- ‡Department of Chemistry, University of British Columbia, 2036 Main Mall Vancouver, British Columbia V6T 1Z1, Canada
| | - Matthew R Smith
- ‡Department of Chemistry, University of British Columbia, 2036 Main Mall Vancouver, British Columbia V6T 1Z1, Canada
| | - Hee-Jong Hwang
- ‡Department of Chemistry, University of British Columbia, 2036 Main Mall Vancouver, British Columbia V6T 1Z1, Canada
| | - Marco A Ciufolini
- ‡Department of Chemistry, University of British Columbia, 2036 Main Mall Vancouver, British Columbia V6T 1Z1, Canada
| | - Don J Mahuran
- †Genetics and Genome Biology, SickKids, PGCRL 686 Bay Street, Toronto, Ontario M5G 0A4, Canada.,§Department of Laboratory Medicine and Pathology, University of Toronto, Medical Science Building, 1 King's College Circle, 6th Floor, Toronto, Ontario M5S 1A8, Canada
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63
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Hay Mele B, Citro V, Andreotti G, Cubellis MV. Drug repositioning can accelerate discovery of pharmacological chaperones. Orphanet J Rare Dis 2015; 10:55. [PMID: 25947946 PMCID: PMC4429356 DOI: 10.1186/s13023-015-0273-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 04/23/2015] [Indexed: 11/10/2022] Open
Abstract
A promising strategy for the treatment of genetic diseases, pharmacological chaperone therapy, has been proposed recently. It exploits small molecules which can be administered orally, reach difficult tissues such as the brain and have low cost. This strategy has a vast field of application. In order to make drug development as fast as possible, it is important to exploit drug repositioning. We evaluated the impact and limitations of this approach for rare diseases and we provide a shortcut in finding drugs for off-target usage.
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Affiliation(s)
- Bruno Hay Mele
- Department of Agricultural and Food Sciences, University Federico II, Naples, Italy.
| | - Valentina Citro
- Department of Biology, University Federico II, Naples, Italy.
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Osher E, Fattal-Valevski A, Sagie L, Urshanski N, Sagiv N, Peleg L, Lerman-Sagie T, Zimran A, Elstein D, Navon R, Valevski A, Stern N. Effect of cyclic, low dose pyrimethamine treatment in patients with Late Onset Tay Sachs: an open label, extended pilot study. Orphanet J Rare Dis 2015; 10:45. [PMID: 25896637 PMCID: PMC4404274 DOI: 10.1186/s13023-015-0260-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/27/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Late Onset Tay- Sachs disease (LOTS) is a rare neurodegenerative lysosomal storage disease which results from mutations in the gene encoding the α subunit (HEXA) of β-hexosaminidase enzyme (HexA). At the present time, no effective treatment exists for LOTS and other neurodegenerative diseases involving the central nerve system (CNS). Pyrimethamine (PMT) was previously shown to act as a HexA chaperone in human fibroblasts in vitro carrying some (e.g., αG269S), but not all LOTS-related mutations. The present study assessed the effect of cyclic, low dose and long term pyrimethamine treatment on HexA in subjects with LOTS. METHODS In an open label trial in 4 LOTS patients, PMT was initiated at an average daily dose of ~2.7 mg and administered cyclically guided by blood lymphocyte HexA activity for a mean duration of 82.8 (±22.5; SD) weeks (~1.5 year). RESULTS HexA activity rose in all subjects, with a mean peak increase of 2.24 folds (±0.52; SD) over baseline activity (range 1.87-3). The mean treatment time required to attain this peak was of 15.7 (±4.8; SD) weeks. Following increase in activity, HexA gradually declined with the continued use of PMT, which was then stopped, resulting in the return of HexA activity to baseline. A second cycle of PMT treatment was then initiated, resulting again in an increase in HexA activity. Three of the patients experienced a measurable neuropsychiatric deterioration whereas one subject remained entirely stable. CONCLUSIONS Cyclic low dose of PMT can increase HexA activity in LOTS patients. However, the observed increase is repeatedly transient and not associated with discernible beneficial neurological or psychiatric effects.
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Affiliation(s)
- Etty Osher
- Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Aviva Fattal-Valevski
- Pediatric Neurology Unit, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Liora Sagie
- Pediatric Neurology Unit, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Nataly Urshanski
- Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Nadav Sagiv
- Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Leah Peleg
- Sheba Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel. .,Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Tally Lerman-Sagie
- Pediatric Neurology Unit, Wolfson Medical Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Ari Zimran
- Shaare Zedek Medical Center, Hadassa School of Medicine, Hebrew University, Jerusalem, Israel.
| | - Deborah Elstein
- Shaare Zedek Medical Center, Hadassa School of Medicine, Hebrew University, Jerusalem, Israel.
| | - Ruth Navon
- Department of Human Genetics, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Avi Valevski
- Tel Aviv-Sourasky Medical Center; Geha Mental Health Center, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Naftali Stern
- Institute of Endocrinology, Metabolism and Hypertension, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Parenti G, Andria G, Valenzano KJ. Pharmacological Chaperone Therapy: Preclinical Development, Clinical Translation, and Prospects for the Treatment of Lysosomal Storage Disorders. Mol Ther 2015; 23:1138-1148. [PMID: 25881001 DOI: 10.1038/mt.2015.62] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/01/2015] [Indexed: 02/06/2023] Open
Abstract
Lysosomal storage disorders (LSDs) are a group of inborn metabolic diseases caused by mutations in genes that encode proteins involved in different lysosomal functions, in most instances acidic hydrolases. Different therapeutic approaches have been developed to treat these disorders. Pharmacological chaperone therapy (PCT) is an emerging approach based on small-molecule ligands that selectively bind and stabilize mutant enzymes, increase their cellular levels, and improve lysosomal trafficking and activity. Compared to other approaches, PCT shows advantages, particularly in terms of oral administration, broad biodistribution, and positive impact on patients' quality of life. After preclinical in vitro and in vivo studies, PCT is now being translated in the first clinical trials, either as monotherapy or in combination with enzyme replacement therapy, for some of the most prevalent LSDs. For some LSDs, the results of the first clinical trials are encouraging and warrant further development. Future research in the field of PCT will be directed toward the identification of novel chaperones, including new allosteric drugs, and the exploitation of synergies between chaperone treatment and other therapeutic approaches.
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Affiliation(s)
- Giancarlo Parenti
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University, Naples, Italy; Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.
| | - Generoso Andria
- Department of Translational Medical Sciences, Section of Pediatrics, Federico II University, Naples, Italy
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Abstract
Striking therapeutic advances for lysosomal diseases have harnessed the biology of this organelle and illustrate its central rôle in the dynamic economy of the cell. Further Innovation will require improved protein-targetting or realization of therapeutic gene- and cell transfer stratagems. Rescuing function before irreversible injury, mandates a deep knowledge of clinical behaviour as well as molecular pathology – and frequently requires an understanding of neuropathology. Whether addressing primary causes, or rebalancing the effects of disordered cell function, true therapeutic innovation depends on continuing scientific exploration of the lysosome. Genuine partnerships between biotech and the patients affected by this extraordinary family of disorders continue to drive productive pharmaceutical discovery.
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Affiliation(s)
- Timothy M Cox
- Department of Medicine, University of Cambridge, UK.
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67
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Knight EM, Williams HN, Stevens AC, Kim SH, Kottwitz JC, Morant AD, Steele JW, Klein WL, Yanagisawa K, Boyd RE, Lockhart DJ, Sjoberg ER, Ehrlich ME, Wustman BA, Gandy S. Evidence that small molecule enhancement of β-hexosaminidase activity corrects the behavioral phenotype in Dutch APP(E693Q) mice through reduction of ganglioside-bound Aβ. Mol Psychiatry 2015; 20:109-17. [PMID: 25349165 PMCID: PMC5189927 DOI: 10.1038/mp.2014.135] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 08/07/2014] [Accepted: 08/28/2014] [Indexed: 01/08/2023]
Abstract
Certain mutant Alzheimer's amyloid-β (Aβ) peptides (that is, Dutch mutant APP(E693Q)) form complexes with gangliosides (GAβ). These mutant Aβ peptides may also undergo accelerated aggregation and accumulation upon exposure to GM2 and GM3. We hypothesized that increasing β-hexosaminidase (β-hex) activity would lead to a reduction in GM2 levels, which in turn, would cause a reduction in Aβ aggregation and accumulation. The small molecule OT1001 is a β-hex-targeted pharmacological chaperone with good bioavailability, blood-brain barrier penetration, high selectivity for β-hex and low cytotoxicity. Dutch APP(E693Q) transgenic mice accumulate oligomeric Aβ as they age, as well as Aβ oligomer-dose-dependent anxiety and impaired novel object recognition (NOR). Treatment of Dutch APP(E693Q) mice with OT1001 caused a dose-dependent increase in brain β-hex levels up to threefold over those observed at baseline. OT1001 treatment was associated with reduced anxiety, improved learning behavior in the NOR task and dramatically reduced GAβ accumulation in the subiculum and perirhinal cortex, both of which are brain regions required for normal NOR. Pharmacological chaperones that increase β-hex activity may be useful in reducing accumulation of certain mutant species of Aβ and in preventing the associated behavioral pathology.
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Affiliation(s)
- E M Knight
- Departments of Neurology and Psychiatry, and Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | | - S H Kim
- Departments of Neurology and Psychiatry, and Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - J C Kottwitz
- Departments of Neurology and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - A D Morant
- Departments of Neurology and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - W L Klein
- Department of Neurobiology and Cognitive Neurology, and Alzheimer's Disease Center, Northwestern University, Evanston, IL, USA
| | - K Yanagisawa
- Research Institute, National Center for Geriatrics and Gerontology, Obu City, Aichi, Japan
| | - R E Boyd
- Amicus Therapeutics, Cranbury, NJ, USA
| | | | | | - M E Ehrlich
- Departments of Neurology and Pediatrics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - S Gandy
- Departments of Neurology and Psychiatry, and Alzheimer's Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- James J. Peters Veterans Affairs Medical Center, Bronx, New York, NY, USA
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68
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Liu T, Xia M, Zhang H, Zhou H, Wang J, Shen X, Yang Q. Exploring NAG-thiazoline and its derivatives as inhibitors of chitinolytic β-acetylglucosaminidases. FEBS Lett 2014; 589:110-6. [PMID: 25436416 DOI: 10.1016/j.febslet.2014.11.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 11/19/2014] [Accepted: 11/20/2014] [Indexed: 10/24/2022]
Abstract
NAG-thiazoline (NGT) and its derivatives are well-known inhibitors against most β-acetylglucosaminidases (β-GlcNAcases) except for insect and bacterial chitinolytic β-GlcNAcases, including the molting-indispensable OfHex1 from the insect Ostrinia furnacalis. Here, we report the co-crystal structure of OfHex1 in complex with NGT. This structure reveals a large active pocket in OfHex1 that may account for the poor inhibitory activity of NGT. To test this hypothesis, a bulky substituent was designed and synthesized on the thiazoline ring of NGT. The resulting compound (NMAGT) was determined to be a submicromolar inhibitor of OfHex1 with a Ki value of 0.13 μM, which is 600-fold lower than Ki value of NGT. Molecular dynamics simulation analysis supported the good fit of NMAGT to the active pocket.
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Affiliation(s)
- Tian Liu
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Meng Xia
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Haitao Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 200237, China
| | - Hao Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Food and Environmental Science and Technology, Dalian University of Technology, Panjin 124000, China
| | - Jing Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Xu Shen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 200237, China
| | - Qing Yang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China.
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Hall P, Minnich S, Teigen C, Raymond K. Diagnosing Lysosomal Storage Disorders: The GM2 Gangliosidoses. ACTA ACUST UNITED AC 2014; 83:17.16.1-8. [PMID: 25271840 DOI: 10.1002/0471142905.hg1716s83] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The GM2 gangliosidoses are a group of autosomal recessive lysosomal storage disorders caused by defective β-hexosaminidase. There are three clinical conditions in this group: Tay-Sachs disease (TSD), Sandhoff disease (SD), and hexosaminidase activator deficiency. The three conditions are clinically indistinguishable. TSD and SD have been identified with infantile, juvenile, and adult onset forms. The activator deficiency is only known to present with infantile onset. Diagnosis of TSD and SD is based on decreased hexosaminidase activity and a change in the percentage of activity between isoforms. There are no biochemical tests currently available for activator deficiency. This unit provides a detailed procedure for identifying TSD and SD in affected individuals and carriers from leukocyte samples, the most robust sample type available.
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Affiliation(s)
- Patricia Hall
- Department of Human Genetics, Emory University, Atlanta, Georgia
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70
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Yong J, Grankvist N, Han J, Kaufman RJ. Eukaryotic translation initiation factor 2 α phosphorylation as a therapeutic target in diabetes. Expert Rev Endocrinol Metab 2014; 9:345-356. [PMID: 30763994 DOI: 10.1586/17446651.2014.927309] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Regulation of mRNA translation is of vital importance for a cell to adapt to environmental changes. To serve this purpose, intricate mechanisms controlling mRNA translation have evolved, of which the eukaryotic initiation factors eIF2 and eIF4 represent essential regulatory nodes for both stress sensing and signal transduction. Stress sensing by eIF2 α subunit (eIF2α) kinases, translation regulation by eIF2α subunit phosphorylation and subsequent dephosphorylation constitute a core molecular switch for stress adaptation and rapid metabolic regulation. It is not surprising; therefore, that dysfunction of such a pathway is implicated in human disease, especially metabolic syndrome and diabetes. In theory, therapeutic intervention to target the eIF2α phosphorylation pathway provides a promising therapeutic solution to tackle this debilitating syndrome. Careful evaluation of such therapies is crucially needed considering the central role of eIF2α pathway in cellular function for every organ.
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Affiliation(s)
| | | | - Jaeseok Han
- a Degenerative Diseases Program, Sanford|Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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Abstract
The lysosomal storage disorders are a clinically heterogeneous group of inborn errors of metabolism, associated with the accumulation of incompletely degraded macromolecules within several cellular sites. Affected individuals present with a broad range of clinical problems, including hepatosplenomegaly and skeletal dysplasia. Onset of symptoms may range from birth to adulthood. Most are associated with neurologic features. Later-onset forms are often misdiagnosed as symptoms, which might include psychiatric manifestations, are slowly progressive, and may precede other neurologic or systemic features. Symptomatic care, which remains the mainstay for most subtypes, can lead to significant improvement in quality of life.
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Affiliation(s)
- Gregory M Pastores
- Departments of Neurology and Pediatrics, New York University School of Medicine, NYU at Rivergate, 403 East 34th Street, 2nd Floor, New York, NY 10016, USA; Neurogenetics Laboratory, New York University School of Medicine, NYU at Rivergate, 403 East 34th Street, 2nd Floor, New York, NY 10016, USA.
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72
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Liquid chromatography/electrospray ionisation-tandem mass spectrometry quantification of GM2 gangliosides in human peripheral cells and plasma. Anal Biochem 2014; 458:20-6. [PMID: 24769373 DOI: 10.1016/j.ab.2014.04.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/14/2014] [Accepted: 04/16/2014] [Indexed: 11/22/2022]
Abstract
GM2 gangliosidosis is a group of inherited neurodegenerative disorders resulting primarily from the excessive accumulation of GM2 gangliosides (GM2) in neuronal cells. As biomarkers for categorising patients and monitoring the effectiveness of developing therapies are lacking for this group of disorders, we sought to develop methodology to quantify GM2 levels in more readily attainable patient samples such as plasma, leukocytes, and cultured skin fibroblasts. Following organic extraction, gangliosides were partitioned into the aqueous phase and isolated using C18 solid-phase extraction columns. Relative quantification of three species of GM2 was achieved using LC/ESI-MS/MS with d35GM1 18:1/18:0 as an internal standard. The assay was linear over the biological range, and all GM2 gangliosidosis patients were demarcated from controls by elevated GM2 in cultured skin fibroblast extracts. However, in leukocytes only some molecular species could be used for differentiation and in plasma only one was informative. A reduction in GM2 was easily detected in patient skin fibroblasts after a short treatment with media from normal cells enriched in secreted β-hexosaminidase. This method may show promise for measuring the effectiveness of experimental therapies for GM2 gangliosidosis by allowing quantification of a reduction in the primary storage burden.
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73
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Sybertz E, Krainc D. Development of targeted therapies for Parkinson's disease and related synucleinopathies. J Lipid Res 2014; 55:1996-2003. [PMID: 24668939 DOI: 10.1194/jlr.r047381] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Therapeutic efforts in neurodegenerative diseases have been very challenging, particularly due to a lack of validated and mechanism-based therapeutic targets and biomarkers. The basic idea underlying the novel therapeutic approaches reviewed here is that by exploring the molecular basis of neurodegeneration in a rare lysosomal disease such as Gaucher's disease (GD), new molecular targets will be identified for therapeutic development in common synucleinopathies. Accumulation of α-synuclein plays a key role in the pathogenesis of Parkinson's disease (PD) and other synucleinopathies, suggesting that improved clearance of α-synuclein may be of therapeutic benefit. To achieve this goal, it is important to identify specific mechanisms and targets involved in the clearance of α-synuclein. Recent discovery of clinical, genetic, and pathological linkage between GD and PD offers a unique opportunity to examine lysosomal glucocerebrosidase, an enzyme mutated in GD, for development of targeted therapies in synucleinopathies. While modulation of glucocerebrosidase and glycolipid metabolism offers a viable approach to treating disorders associated with synuclein accumulation, the compounds described to date either lack the ability to penetrate the CNS or have off-target effects that may counteract or limit their capabilities to mediate the desired pharmacological action. However, recent emergence of selective inhibitors of glycosphingolipid biosynthesis and noninhibitory pharmacological chaperones of glycosphingolipid processing enzymes that gain access to the CNS provide a novel approach that may overcome some of the limitations of compounds reported to date. These new strategies may allow for development of targeted treatments for synucleinopathies that affect both children and adults.
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Affiliation(s)
| | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611
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74
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Abstract
A growing body of evidence suggests that misfolding of a mutant protein followed by its aggregation or premature degradation in the endoplasmic reticulum is one of the main mechanisms that underlie inherited neurodegenerative diseases, including lysosomal storage diseases. Chemical or pharmacological chaperones are small molecules that bind to and stabilize mutant lysosomal enzyme proteins in the endoplasmic reticulum. A number of chaperone compounds for lysosomal hydrolases have been identified in the last decade. They have gained attention because they can be orally administrated, and also because they can penetrate the blood-brain barrier. In this article, we describe two chaperone candidates for the treatment of GM1-gangliosidosis. We also discuss the future direction of this strategy targeting other lysosomal storage diseases as well as protein misfolding diseases in general.
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75
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Shayman JA, Larsen SD. The development and use of small molecule inhibitors of glycosphingolipid metabolism for lysosomal storage diseases. J Lipid Res 2014; 55:1215-25. [PMID: 24534703 DOI: 10.1194/jlr.r047167] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Glycosphingolipid (GSL) storage diseases have been the focus of efforts to develop small molecule therapeutics from design, experimental proof of concept studies, and clinical trials. Two primary alternative strategies that have been pursued include pharmacological chaperones and GSL synthase inhibitors. There are theoretical advantages and disadvantages to each of these approaches. Pharmacological chaperones are specific for an individual glycoside hydrolase and for the specific mutation present, but no candidate chaperone has been demonstrated to be effective for all mutations leading to a given disorder. Synthase inhibitors target single enzymes such as glucosylceramide synthase and inhibit the formation of multiple GSLs. A glycolipid synthase inhibitor could potentially be used to treat multiple diseases, but at the risk of lowering nontargeted cellular GSLs that are important for normal health. The basis for these strategies and specific examples of compounds that have led to clinical trials is the focus of this review.
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Affiliation(s)
- James A Shayman
- Department of Internal Medicine and Vahlteich Medicinal Chemistry Core, University of Michigan, Ann Arbor, MI 48109
| | - Scott D Larsen
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109
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SUZUKI Y. Emerging novel concept of chaperone therapies for protein misfolding diseases. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2014; 90:145-62. [PMID: 24814990 PMCID: PMC4104511 DOI: 10.2183/pjab.90.145] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 03/14/2014] [Indexed: 06/03/2023]
Abstract
Chaperone therapy is a newly developed molecular therapeutic approach to protein misfolding diseases. Among them we found unstable mutant enzyme proteins in a few lysosomal diseases, resulting in rapid intracellular degradation and loss of function. Active-site binding low molecular competitive inhibitors (chemical chaperones) paradoxically stabilized and enhanced the enzyme activity in somatic cells by correction of the misfolding of enzyme protein. They reached the brain through the blood-brain barrier after oral administration, and corrected pathophysiology of the disease. In addition to these inhibitory chaperones, non-competitive chaperones without inhibitory bioactivity are being developed. Furthermore molecular chaperone therapy utilizing the heat shock protein and other chaperone proteins induced by small molecules has been experimentally tried to handle abnormally accumulated proteins as a new approach particularly to neurodegenerative diseases. These three types of chaperones are promising candidates for various types of diseases, genetic or non-genetic, and neurological or non-neurological, in addition to lysosomal diseases.
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Affiliation(s)
- Yoshiyuki SUZUKI
- Special Visiting Scientist, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
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77
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Chaperone therapy for GM2 gangliosidosis: effects of pyrimethamine on β-hexosaminidase activity in Sandhoff fibroblasts. Mol Neurobiol 2013; 50:159-67. [PMID: 24356898 DOI: 10.1007/s12035-013-8605-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 12/08/2013] [Indexed: 12/20/2022]
Abstract
Sphingolipidoses are inherited genetic diseases due to mutations in genes encoding proteins involved in the lysosomal catabolism of sphingolipids. Despite a low incidence of each individual disease, altogether, the number of patients involved is relatively high and resolutive approaches for treatment are still lacking. The chaperone therapy is one of the latest pharmacological approaches to these storage diseases. This therapy allows the mutated protein to escape its natural removal and to increase its quantity in lysosomes, thus partially restoring the metabolic functions. Sandhoff disease is an autosomal recessive inherited disorder resulting from β-hexosaminidase deficiency and characterized by large accumulation of GM2 ganglioside in brain. No enzymatic replacement therapy is currently available, and the use of inhibitors of glycosphingolipid biosynthesis for substrate reduction therapy, although very promising, is associated with serious side effects. The chaperone pyrimethamine has been proposed as a very promising drug in those cases characterized by a residual enzyme activity. In this review, we report the effect of pyrimethamine on the recovery of β-hexosaminidase activity in cultured fibroblasts from Sandhoff patients.
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78
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Patil SA, Maegawa GHB. Developing therapeutic approaches for metachromatic leukodystrophy. DRUG DESIGN DEVELOPMENT AND THERAPY 2013; 7:729-45. [PMID: 23966770 PMCID: PMC3743609 DOI: 10.2147/dddt.s15467] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metachromatic leukodystrophy (MLD) is an autosomal recessive lysosomal disorder caused by the deficiency of arylsulfatase A (ASA), resulting in impaired degradation of sulfatide, an essential sphingolipid of myelin. The clinical manifestations of MLD are characterized by progressive demyelination and subsequent neurological symptoms resulting in severe debilitation. The availability of therapeutic options for treating MLD is limited but expanding with a number of early stage clinical trials already in progress. In the development of therapeutic approaches for MLD, scientists have been facing a number of challenges including blood–brain barrier (BBB) penetration, safety issues concerning therapies targeting the central nervous system, uncertainty regarding the ideal timing for intervention in the disease course, and the lack of more in-depth understanding of the molecular pathogenesis of MLD. Here, we discuss the current status of the different approaches to developing therapies for MLD. Hematopoietic stem cell transplantation has been used to treat MLD patients, utilizing both umbilical cord blood and bone marrow sources. Intrathecal enzyme replacement therapy and gene therapies, administered locally into the brain or by generating genetically modified hematopoietic stem cells, are emerging as novel strategies. In pre-clinical studies, different cell delivery systems including microencapsulated cells or selectively neural cells have shown encouraging results. Small molecules that are more likely to cross the BBB can be used as enzyme enhancers of diverse ASA mutants, either as pharmacological chaperones, or proteostasis regulators. Specific small molecules may also be used to reduce the biosynthesis of sulfatides, or target different affected downstream pathways secondary to the primary ASA deficiency. Given the progressive neurodegenerative aspects of MLD, also seen in other lysosomal diseases, current and future therapeutic strategies will be complementary, whether used in combination or separately at specific stages of the disease course, to produce better outcomes for patients afflicted with this devastating inherited disorder.
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Affiliation(s)
- Shilpa A Patil
- McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins School of Medicine, Baltimore, MD, USA
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79
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A rapid and sensitive method for measuring N-acetylglucosaminidase activity in cultured cells. PLoS One 2013; 8:e68060. [PMID: 23840811 PMCID: PMC3695942 DOI: 10.1371/journal.pone.0068060] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 05/25/2013] [Indexed: 11/19/2022] Open
Abstract
A rapid and sensitive method to quantitatively assess N-acetylglucosaminidase (NAG) activity in cultured cells is highly desirable for both basic research and clinical studies. NAG activity is deficient in cells from patients with Mucopolysaccharidosis type IIIB (MPS IIIB) due to mutations in NAGLU, the gene that encodes NAG. Currently available techniques for measuring NAG activity in patient-derived cell lines include chromogenic and fluorogenic assays and provide a biochemical method for the diagnosis of MPS IIIB. However, standard protocols require large amounts of cells, cell disruption by sonication or freeze-thawing, and normalization to the cellular protein content, resulting in an error-prone procedure that is material- and time-consuming and that produces highly variable results. Here we report a new procedure for measuring NAG activity in cultured cells. This procedure is based on the use of the fluorogenic NAG substrate, 4-Methylumbelliferyl-2-acetamido-2-deoxy-alpha-D-glucopyranoside (MUG), in a one-step cell assay that does not require cell disruption or post-assay normalization and that employs a low number of cells in 96-well plate format. We show that the NAG one-step cell assay greatly discriminates between wild-type and MPS IIIB patient-derived fibroblasts, thus providing a rapid method for the detection of deficiencies in NAG activity. We also show that the assay is sensitive to changes in NAG activity due to increases in NAGLU expression achieved by either overexpressing the transcription factor EB (TFEB), a master regulator of lysosomal function, or by inducing TFEB activation chemically. Because of its small format, rapidity, sensitivity and reproducibility, the NAG one-step cell assay is suitable for multiple procedures, including the high-throughput screening of chemical libraries to identify modulators of NAG expression, folding and activity, and the investigation of candidate molecules and constructs for applications in enzyme replacement therapy, gene therapy, and combination therapies.
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Guo P, Chen Q, Liu T, Xu L, Yang Q, Qian X. Development of Unsymmetrical Dyads As Potent Noncarbohydrate-Based Inhibitors against Human β-N-Acetyl-d-hexosaminidase. ACS Med Chem Lett 2013; 4:527-31. [PMID: 24900704 DOI: 10.1021/ml300475m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 04/24/2013] [Indexed: 11/30/2022] Open
Abstract
Human β-N-acetyl-d-hexosaminidase has gained much attention due to its roles in several pathological processes and been considered as potential targets for disease therapy. A novel and efficient skeleton, which was an unsymmetrical dyad containing naphthalimide and methoxyphenyl moieties with an alkylamine spacer linkage as a noncarbohydrate-based inhibitor, was synthesized, and the activities were valuated against human β-N-acetyl-d-hexosaminidase. The most potent inhibitor exhibits high inhibitory activity with K i values of 0.63 μM. The straightforward synthetic manners of these unsymmetrical dyads and understanding of the binding model could be advantageous for further structure optimization and development of new therapeutic agents for Hex-related diseases.
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Affiliation(s)
- Peng Guo
- Shanghai Key
Laboratory of Chemical Biology, Institute of Pesticides and Pharmaceuticals,
School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Qi Chen
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Tian Liu
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Lin Xu
- Shanghai Key
Laboratory of Chemical Biology, Institute of Pesticides and Pharmaceuticals,
School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
| | - Qing Yang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Xuhong Qian
- Shanghai Key
Laboratory of Chemical Biology, Institute of Pesticides and Pharmaceuticals,
School of Pharmacy, East China University of Science and Technology, Shanghai 200237, China
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81
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Yasui N, Takaoka Y, Nishio H, Nurputra DK, Sekiguchi K, Hamaguchi H, Kowa H, Maeda E, Sugano A, Miura K, Sakaeda T, Kanda F, Toda T. Molecular pathology of Sandhoff disease with p.Arg505Gln in HEXB: application of simulation analysis. J Hum Genet 2013; 58:611-7. [DOI: 10.1038/jhg.2013.68] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 05/15/2013] [Accepted: 05/19/2013] [Indexed: 11/09/2022]
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82
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83
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Boyd RE, Lee G, Rybczynski P, Benjamin ER, Khanna R, Wustman BA, Valenzano KJ. Pharmacological chaperones as therapeutics for lysosomal storage diseases. J Med Chem 2013; 56:2705-25. [PMID: 23363020 DOI: 10.1021/jm301557k] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Lysosomal enzymes are responsible for the degradation of a wide variety of glycolipids, oligosaccharides, proteins, and glycoproteins. Inherited mutations in the genes that encode these proteins can lead to reduced stability of newly synthesized lysosomal enzymes. While often catalytically competent, the mutated enzymes are unable to efficiently pass the quality control mechanisms of the endoplasmic reticulum, resulting in reduced lysosomal trafficking, substrate accumulation, and cellular dysfunction. Pharmacological chaperones (PCs) are small molecules that bind and stabilize mutant lysosomal enzymes, thereby allowing proper cellular translocation. Such compounds have been shown to increase enzyme activity and reduce substrate burden in a number of preclinical models and clinical studies. In this Perspective, we review several of the lysosomal diseases for which PCs have been studied and the SAR of the various classes of molecules.
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Affiliation(s)
- Robert E Boyd
- Amicus Therapeutics, 1 Cedar Brook Drive, Cranbury, New Jersey 08512, United States.
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84
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Sampson HM, Lam H, Chen PC, Zhang D, Mottillo C, Mirza M, Qasim K, Shrier A, Shyng SL, Hanrahan JW, Thomas DY. Compounds that correct F508del-CFTR trafficking can also correct other protein trafficking diseases: an in vitro study using cell lines. Orphanet J Rare Dis 2013; 8:11. [PMID: 23316740 PMCID: PMC3558398 DOI: 10.1186/1750-1172-8-11] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 01/01/2013] [Indexed: 11/12/2022] Open
Abstract
Background Many genetic diseases are due to defects in protein trafficking where the mutant protein is recognized by the quality control systems, retained in the endoplasmic reticulum (ER), and degraded by the proteasome. In many cases, the mutant protein retains function if it can be trafficked to its proper cellular location. We have identified structurally diverse correctors that restore the trafficking and function of the most common mutation causing cystic fibrosis, F508del-CFTR. Most of these correctors do not act directly as ligands of CFTR, but indirectly on other pathways to promote folding and correction. We hypothesize that these proteostasis regulators may also correct other protein trafficking diseases. Methods To test our hypothesis, we used stable cell lines or transient transfection to express 2 well-studied trafficking disease mutations in each of 3 different proteins: the arginine-vasopressin receptor 2 (AVPR2, also known as V2R), the human ether-a-go-go-related gene (KCNH2, also known as hERG), and finally the sulfonylurea receptor 1 (ABCC8, also known as SUR1). We treated cells expressing these mutant proteins with 9 structurally diverse F508del-CFTR correctors that function through different cellular mechanisms and assessed whether correction occurred via immunoblotting and functional assays. Results were deemed significantly different from controls by a one-way ANOVA (p < 0.05). Results Here we show that F508del-CFTR correctors RDR1, KM60 and KM57 also correct some mutant alleles of other protein trafficking diseases. We also show that one corrector, the cardiac glycoside ouabain, was found to alter the glycosylation of all mutant alleles tested. Conclusions Correctors of F508del-CFTR trafficking might have broader applications to other protein trafficking diseases.
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Affiliation(s)
- Heidi M Sampson
- Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, McIntyre Medical Building, Montréal, Québec H3G 1Y6, Canada
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85
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Pharmacological chaperones for enzyme enhancement therapy in genetic diseases. Pharm Pat Anal 2013; 2:109-24. [DOI: 10.4155/ppa.12.74] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pharmacological chaperone therapy (PCT) is a rather new approach consisting in targeting incorrectly folded proteins by small molecules, thus, facilitating the correct folding of the protein and inducing a recovery of its functionality. Many diseases result from mutations on specific genes; this patent review focuses on those pathologies where PCT has a potential application for enzymatic enhancement. Rare diseases are the main area where PCT has been applied and the most advanced compounds are aiming to cure lysosomal storage disorders such as Fabry, Pompe or Gaucher. Until now, most compounds used as pharmacological chaperones were based on substrate-like chemical structures but recently new nonsubstrate-like and non-inhibitory compounds have been disclosed for Gaucher and Pompe diseases. This initiates a new era for pharmacological chaperones with more diverse chemical structures and binding modes. This review covers the patents relating to enzyme enhancement on pharmacological chaperone therapy. Only an update is presented for Gaucher disease, where PCT is highly applied and recently reviewed.
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86
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Pierson TM, Torres PA, Zeng BJ, Glanzman AM, Adams D, Finkel RS, Mahuran DJ, Pastores GM, Tennekoon GI, Kolodny EH. Juvenile-onset motor neuron disease caused by novel mutations in β-hexosaminidase. Mol Genet Metab 2013; 108:65-9. [PMID: 23158871 PMCID: PMC3601980 DOI: 10.1016/j.ymgme.2012.10.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 10/28/2012] [Accepted: 10/28/2012] [Indexed: 10/27/2022]
Abstract
A 12 year-old female presented with a seven-year history of progressive muscle weakness, atrophy, tremor and fasciculations. Cognition was normal. Rectal biopsy revealed intracellular storage material and biochemical testing indicated low hexosaminidase activity consistent with juvenile-onset G(M2)-gangliosidosis. Genetic evaluation revealed compound heterozygosity with two novel mutations in the hexosaminidase β-subunit (c.512-3 C>A and c.1613+15_1613+18dup). Protein analysis was consistent with biochemical findings and indicated only a small portion of β-subunits were properly processed. These results provide additional insight into juvenile-onset G(M2)-gangliosidoses and further expand the number of β-hexosaminidase mutations associated with motor neuron disease.
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Affiliation(s)
- Tyler Mark Pierson
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
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87
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Cox TM. Therapeutic opportunities for lysosomal diseases affecting the brain. Clin Med (Lond) 2012. [DOI: 10.7861/clinmedicine.12-6-s33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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88
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Mahley RW, Huang Y. Small-molecule structure correctors target abnormal protein structure and function: structure corrector rescue of apolipoprotein E4-associated neuropathology. J Med Chem 2012; 55:8997-9008. [PMID: 23013167 PMCID: PMC4904786 DOI: 10.1021/jm3008618] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
An attractive strategy to treat proteinopathies (diseases caused by malformed or misfolded proteins) is to restore protein function by inducing proper three-dimensional structure. We hypothesized that this approach would be effective in reversing the detrimental effects of apolipoprotein (apo) E4, the major allele that significantly increases the risk of developing Alzheimer's disease and other neurodegenerative disorders. ApoE4's detrimental effects result from its altered protein conformation ("domain interaction"), making it highly susceptible to proteolytic cleavage and the generation of neurotoxic fragments. Here, we review apoE structure and function and how apoE4 causes neurotoxicity, and describe the identification of potent small-molecule-based "structure correctors" that induce proper apoE4 folding. SAR studies identified a series of small molecules that significantly reduced apoE4's neurotoxic effects in cultured neurons and a series that reduced apoE4 fragment levels in vivo, providing proof-of-concept for our approach. Structure-corrector-based therapies could prove to be highly effective for the treatment of many protein-misfolding diseases.
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Affiliation(s)
- Robert W Mahley
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California 94158, United States.
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89
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Ribbens J, Whiteley G, Furuya H, Southall N, Hu X, Marugan J, Ferrer M, Maegawa GHB. A high-throughput screening assay using Krabbe disease patient cells. Anal Biochem 2012; 434:15-25. [PMID: 23138179 DOI: 10.1016/j.ab.2012.10.034] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 10/07/2012] [Accepted: 10/24/2012] [Indexed: 01/13/2023]
Abstract
Globoid cell leukodystrophy (GLD) or Krabbe disease is a lysosomal disease caused by β-galactocerebrosidase (GALC) deficiency resulting in a rapidly progressive neurodegenerative disorder. Unfortunately, the only available treatment is hematopoietic bone marrow transplantation, which prevents its fulminant manifestation but without treating further neurological manifestations. Here, we describe the development of a cellular high-throughput screening (HTS) assay using GLD patient fibroblasts to screen for small molecules that enhance the residual mutant GALC enzymatic activity. Small molecules have substantial therapeutic potential in GLD because they are more prone to cross the blood-brain barrier, reaching the neuronal affected cells. The transformation of primary skin fibroblasts with SV40 large T antigen has been shown to maintain the biochemical characteristics of the GLD cells and generates sufficient cells for the HTS. Using a specific fluorescent substrate, residual GALC activity from an SV40-transformed GLD patient fibroblast was measurable in high-density microplates. The pilot quantitative HTS against a small compound collection showed robust statistics. The small molecules that showed active concentration-response curves were further studied in primary GLD fibroblasts. This cell-based HTS assay demonstrates the feasibility of employing live GLD patient cells to identify therapeutic agents that can potentially be used for the treatment of this progressive neurodegenerative disease.
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Affiliation(s)
- Jameson Ribbens
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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90
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Abstract
UNLABELLED The enzymatic profile of lysosomal exoglycosidases in middle ear cholesteatoma has not been well known. The assessment of glycoconjugate catabolism may contribute to a better understanding of cholesteatoma pathogenesis. OBJECTIVE The study aim was to evaluate catabolic processes of glycoproteins, glycolipids, and proteoglycans in cholesteatoma through outlining the concentration of N-acetyl-β-hexosaminidase (HEX), β-glucuronidase (GLUC), and β-galactosidase (GAL) activity as well as in serum of cholesteatoma patients and healthy volunteers. STUDY DESIGN Acquired cholesteatomas (n = 25) and normal retroauricular skin specimens (n = 25) were taken during surgery as well as serum from cholesteatoma patients and healthy volunteers. HEX, GAL, and GLUC activity was assessed on basis of p-nitrophenol release from derivatives of the substrate (HEX: N-acetylglucosamine i N-acetylgalactosamine, GAL from galactose, and GLUC from glucuronide). RESULTS The mean concentration of activity of HEX 1142.39 pKat/ml, GAL 8.90 pKat/ml, and GLUC 14.06 pKat/ml was significantly higher compared with the concentration of enzyme activity in normal tissue: HEX 267.65 pKat/ml, GAL 3.44 pKat/ml, and GLUC 3.90 pKat/ml. In the serum of cholesteatoma patients, the mean concentration of enzyme activities were as follows: HEX 641.62 pKat/ml, GAL 4.55 pKat/ml, and GLUC 12.80 pKat/ml and were significantly higher compared with the concentration of HEX activity (215.75 pKat/ml), GAL (1.89 pKat/ml), and GLUC (5.51 pKat/ml) in the serum of the healthy control group. In cholesteatoma compared with the normal tissue, there is an increase of the glycoconjugate catabolism due to significantly higher concentration of HEX, GAL, and GLUC activity in cholesteatoma. Cholesteatoma causes systemic reaction due to the increase of HEX, GAL, and GLUC activity in patient serum.
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91
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Lange DJ, Andersen PM, Remanan R, Marklund S, Benjamin D. Pyrimethamine decreases levels of SOD1 in leukocytes and cerebrospinal fluid of ALS patients: a phase I pilot study. Amyotroph Lateral Scler Frontotemporal Degener 2012; 14:199-204. [PMID: 22985433 DOI: 10.3109/17482968.2012.724074] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The mutated SOD1 protein appears to have a gene dose-dependent effect on the severity and progression of ALS. Lowering of SOD1 protein levels might reduce severity and progression of the disease. The antimalarial drug pyrimethamine (PYR) was identified to cause a dose-dependent reduction in SOD1 protein levels in human cells in vitro. To determine if there was a similar effect in humans, we performed a phase I pilot study in 16 ALS patients with SOD1 mutations, 18 weeks in duration. Blood samples were obtained during all visits. The actin normalized leukocyte SOD1 levels were analyzed using Western blot. SOD1 content in the cerebrospinal fluid (CSF) was determined by ELISA and the SOD1 enzymic activity by spectrophotometric analysis using KO2. Clinical assessment of disease severity was assessed using Appel ALS scale and ALSFRS-R. The leukocyte SOD1 levels showed a significant reduction (p > 0.0001) by the third study visit and this reduction was sustained throughout the remainder of the study. CSF also showed a decrease in SOD1 protein content and enzymic activity in the two patients so tested. Thus, PYR use may be associated with a reduction in SOD1 in ALS patients. The significance is uncertain and further detailed study is required.
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Affiliation(s)
- Dale J Lange
- Department of Neurology, Hospital for Special Surgery, New York, NY 10021, USA.
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92
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Huang HP, Chuang CY, Kuo HC. Induced pluripotent stem cell technology for disease modeling and drug screening with emphasis on lysosomal storage diseases. Stem Cell Res Ther 2012; 3:34. [PMID: 22925465 PMCID: PMC3580472 DOI: 10.1186/scrt125] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The recent derivation of disease-specific induced pluripotent stem cells (iPSCs) from somatic cells of patients with familial and sporadic forms of diseases and the demonstration of their ability to give rise to disease-relevant cell types provide an excellent opportunity to gain further insights into the mechanisms responsible for the pathophysiology of these diseases and develop novel therapeutic drugs. Here, we review the recent advances in iPSC technology for modeling of various lysosomal storage diseases (LSDs) and discuss possible strategies through which LSD-iPSCs can be exploited to identify novel drugs and improve future clinical treatment of LSDs.
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93
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Guerriero CJ, Brodsky JL. The delicate balance between secreted protein folding and endoplasmic reticulum-associated degradation in human physiology. Physiol Rev 2012; 92:537-76. [PMID: 22535891 DOI: 10.1152/physrev.00027.2011] [Citation(s) in RCA: 308] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Protein folding is a complex, error-prone process that often results in an irreparable protein by-product. These by-products can be recognized by cellular quality control machineries and targeted for proteasome-dependent degradation. The folding of proteins in the secretory pathway adds another layer to the protein folding "problem," as the endoplasmic reticulum maintains a unique chemical environment within the cell. In fact, a growing number of diseases are attributed to defects in secretory protein folding, and many of these by-products are targeted for a process known as endoplasmic reticulum-associated degradation (ERAD). Since its discovery, research on the mechanisms underlying the ERAD pathway has provided new insights into how ERAD contributes to human health during both normal and diseases states. Links between ERAD and disease are evidenced from the loss of protein function as a result of degradation, chronic cellular stress when ERAD fails to keep up with misfolded protein production, and the ability of some pathogens to coopt the ERAD pathway. The growing number of ERAD substrates has also illuminated the differences in the machineries used to recognize and degrade a vast array of potential clients for this pathway. Despite all that is known about ERAD, many questions remain, and new paradigms will likely emerge. Clearly, the key to successful disease treatment lies within defining the molecular details of the ERAD pathway and in understanding how this conserved pathway selects and degrades an innumerable cast of substrates.
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Affiliation(s)
- Christopher J Guerriero
- Department of Biological Sciences, University of Pittsburgh, A320 Langley Hall, Pittsburgh, PA 15260, USA
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94
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Smith NJ, Winstone AM, Stellitano L, Cox TM, Verity CM. GM2 gangliosidosis in a UK study of children with progressive neurodegeneration: 73 cases reviewed. Dev Med Child Neurol 2012; 54:176-82. [PMID: 22115551 DOI: 10.1111/j.1469-8749.2011.04160.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To report the demographic, phenotypic, and time-to-diagnosis characteristics of children with GM2 gangliosidosis referred to the UK study of Progressive Intellectual and Neurological Deterioration. METHOD Case notification is made via monthly surveillance card, administered by the British Paediatric Surveillance Unit to all UK-based paediatricians; children with GM2 gangliosidosis were identified from cases satisfying inclusion in the UK study of Progressive Intellectual and Neurological Deterioration and analysed according to phenotypic and biochemical categories. RESULTS Between May 1997 and January 2010, 73 individuals with GM2 gangliosidoses were reported: 40 with Tay-Sachs disease, 31 with Sandhoff disease, and two with GM2 activator protein deficiency. Together they account for 6% (73/1164) of all diagnosed cases of progressive intellectual and neurological deterioration. The majority (62/73) were sporadic index cases with no family history. Children of Pakistani ancestry were overrepresented in all subtypes, particularly juvenile Sandhoff disease, accounting for 10 of 11 notified cases. Infantile-onset variants predominated (55/73); the mean age at onset of symptoms was 6.2 and 4.7 months for infantile-onset Tay-Sachs and Sandhoff disease respectively, and 26.2 and 34.7 months for the corresponding juvenile-onset variants. Time to diagnosis averaged 7.4 months and 28.0 months in infantile- and juvenile-onset disease respectively. INTERPRETATION GM2 gangliosidosis is a significant cause of childhood neurodegenerative disease; timely diagnosis relies upon improved clinical recognition, which may be increasingly important as specific therapies become available. There is a potential benefit from the introduction of screening programmes for high-risk ethnic groups.
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Affiliation(s)
- Nicholas J Smith
- Lysosomal Diseases Research Group, Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
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95
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Novel patient cell-based HTS assay for identification of small molecules for a lysosomal storage disease. PLoS One 2011; 6:e29504. [PMID: 22216298 PMCID: PMC3244463 DOI: 10.1371/journal.pone.0029504] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 11/29/2011] [Indexed: 12/04/2022] Open
Abstract
Small molecules have been identified as potential therapeutic agents for lysosomal storage diseases (LSDs), inherited metabolic disorders caused by defects in proteins that result in lysosome dysfunctional. Some small molecules function assisting the folding of mutant misfolded lysosomal enzymes that are otherwise degraded in ER-associated degradation. The ultimate result is the enhancement of the residual enzymatic activity of the deficient enzyme. Most of the high throughput screening (HTS) assays developed to identify these molecules are single-target biochemical assays. Here we describe a cell-based assay using patient cell lines to identify small molecules that enhance the residual arylsulfatase A (ASA) activity found in patients with metachromatic leukodystrophy (MLD), a progressive neurodegenerative LSD. In order to generate sufficient cell lines for a large scale HTS, primary cultured fibroblasts from MLD patients were transformed using SV40 large T antigen. These SV40 transformed (SV40t) cells showed to conserve biochemical characteristics of the primary cells. Using a specific colorimetric substrate para-nitrocatechol sulfate (pNCS), detectable ASA residual activity were observed in primary and SV40t fibroblasts from a MLD patient (ASA-I179S) cultured in multi-well plates. A robust fluorescence ASA assay was developed in high-density 1,536-well plates using the traditional colorimetric pNCS substrate, whose product (pNC) acts as “plate fluorescence quencher” in white solid-bottom plates. The quantitative cell-based HTS assay for ASA generated strong statistical parameters when tested against a diverse small molecule collection. This cell-based assay approach can be used for several other LSDs and genetic disorders, especially those that rely on colorimetric substrates which traditionally present low sensitivity for assay-miniaturization. In addition, the quantitative cell-based HTS assay here developed using patient cells creates an opportunity to identify therapeutic small molecules in a disease-cellular environment where potentially disrupted pathways are exposed and available as targets.
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96
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Wang F, Song W, Brancati G, Segatori L. Inhibition of endoplasmic reticulum-associated degradation rescues native folding in loss of function protein misfolding diseases. J Biol Chem 2011; 286:43454-64. [PMID: 22006919 DOI: 10.1074/jbc.m111.274332] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lysosomal storage disorders are often caused by mutations that destabilize native folding and impair trafficking of secretory proteins. We demonstrate that endoplasmic reticulum (ER)-associated degradation (ERAD) prevents native folding of mutated lysosomal enzymes in patient-derived fibroblasts from two clinically distinct lysosomal storage disorders, namely Gaucher and Tay-Sachs disease. Prolonging ER retention via ERAD inhibition enhanced folding, trafficking, and activity of these unstable enzyme variants. Furthermore, combining ERAD inhibition with enhancement of the cellular folding capacity via proteostasis modulation resulted in synergistic rescue of mutated enzymes. ERAD inhibition was achieved by cell treatment with small molecules that interfere with recognition (kifunensine) or retrotranslocation (eeyarestatin I) of misfolded substrates. These different mechanisms of ERAD inhibition were shown to enhance ER retention of mutated proteins but were associated with dramatically different levels of ER stress, unfolded protein response activation, and unfolded protein response-induced apoptosis.
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Affiliation(s)
- Fan Wang
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas 77005, USA
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97
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Schultz ML, Tecedor L, Chang M, Davidson BL. Clarifying lysosomal storage diseases. Trends Neurosci 2011; 34:401-10. [PMID: 21723623 DOI: 10.1016/j.tins.2011.05.006] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 05/17/2011] [Accepted: 05/27/2011] [Indexed: 11/29/2022]
Abstract
Lysosomal storage diseases (LSDs) are a class of metabolic disorders caused by mutations in proteins critical for lysosomal function. Such proteins include lysosomal enzymes, lysosomal integral membrane proteins, and proteins involved in the post-translational modification and trafficking of lysosomal proteins. There are many recognized forms of LSDs and, although individually rare, their combined prevalence is estimated to be 1 in 8000 births. Over two-thirds of LSDs involve central nervous system (CNS) dysfunction (progressive cognitive and motor decline) and these symptoms are often the most debilitating. Although the genetic basis for these disorders is clear and the biochemistry of the proteins well understood, the cellular mechanisms by which deficiencies in these proteins disrupt neuronal viability remain ambiguous. In this review, we provide an overview of the widespread cellular perturbations occurring in LSDs, how they might be linked and interventions that may specifically or globally correct those defects.
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Affiliation(s)
- Mark L Schultz
- Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
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98
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Valenzano KJ, Khanna R, Powe AC, Boyd R, Lee G, Flanagan JJ, Benjamin ER. Identification and characterization of pharmacological chaperones to correct enzyme deficiencies in lysosomal storage disorders. Assay Drug Dev Technol 2011; 9:213-35. [PMID: 21612550 PMCID: PMC3102255 DOI: 10.1089/adt.2011.0370] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many human diseases result from mutations in specific genes. Once translated, the resulting aberrant proteins may be functionally competent and produced at near-normal levels. However, because of the mutations, the proteins are recognized by the quality control system of the endoplasmic reticulum and are not processed or trafficked correctly, ultimately leading to cellular dysfunction and disease. Pharmacological chaperones (PCs) are small molecules designed to mitigate this problem by selectively binding and stabilizing their target protein, thus reducing premature degradation, facilitating intracellular trafficking, and increasing cellular activity. Partial or complete restoration of normal function by PCs has been shown for numerous types of mutant proteins, including secreted proteins, transcription factors, ion channels, G protein-coupled receptors, and, importantly, lysosomal enzymes. Collectively, lysosomal storage disorders (LSDs) result from genetic mutations in the genes that encode specific lysosomal enzymes, leading to a deficiency in essential enzymatic activity and cellular accumulation of the respective substrate. To date, over 50 different LSDs have been identified, several of which are treated clinically with enzyme replacement therapy or substrate reduction therapy, although insufficiently in some cases. Importantly, a wide range of in vitro assays are now available to measure mutant lysosomal enzyme interaction with and stabilization by PCs, as well as subsequent increases in cellular enzyme levels and function. The application of these assays to the identification and characterization of candidate PCs for mutant lysosomal enzymes will be discussed in this review. In addition, considerations for the successful in vivo use and development of PCs to treat LSDs will be discussed.
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99
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Benito JM, García Fernández JM, Mellet CO. Pharmacological chaperone therapy for Gaucher disease: a patent review. Expert Opin Ther Pat 2011; 21:885-903. [DOI: 10.1517/13543776.2011.569162] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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100
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Abstract
There are over 70 human diseases that are caused by defects in various aspects of lysosomal function. Until 20 years ago, the only specific therapy available for lysosomal storage disorders was allogeneic haemopoietic stem cell transplantation. Over the last two decades, there has been remarkable progress and there are now licensed treatments for seven of these diseases. In some cases, a choice of agents is available. For selected enzyme-deficiency disordes, ERT (enzyme-replacement therapy) has proved to be highly effective. In other cases, ERT has been less impressive, and it seems that it is not possible to efficiently deliver recombinant enzyme to all tissues. These difficulties have led to the development of other small-molecule-based therapies, and a drug for SRT (substrate-reduction therapy) is now licensed and potential chaperone molecules for ERT are in the late stages of clinical development. Nonetheless, there is still significant unmet clinical need, particularly when it comes to treating LSDs which affect the brain. LSDs have led the way in the development of treatment for genetic disorders, and it seems likely that there will be further therapeutic innovations in the future.
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