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Libberecht K, Vangansewinkel T, Van Den Bosch L, Lambrichts I, Wolfs E. Proteostasis plays an important role in demyelinating Charcot Marie Tooth disease. Biochem Pharmacol 2023; 216:115760. [PMID: 37604292 DOI: 10.1016/j.bcp.2023.115760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 08/23/2023]
Abstract
Type 1 Charcot-Marie-Tooth disease (CMT1) is the most common demyelinating peripheral neuropathy. Patients suffer from progressive muscle weakness and sensory problems. The underlying disease mechanisms of CMT1 are still unclear and no therapy is currently available, hence patients completely rely on supportive care. Balancing protein levels is a complex multistep process fundamental to maintain cells in their healthy state and a disrupted proteostasis is a hallmark of several neurodegenerative diseases. When protein misfolding occurs, protein quality control systems are activated such as chaperones, the lysosomal-autophagy system and proteasomal degradation to ensure proper degradation. However, in pathological circumstances, these mechanisms are overloaded and thereby become inefficient to clear the load of misfolded proteins. Recent evidence strongly indicates that a disbalance in proteostasis plays an important role in several forms of CMT1. In this review, we present an overview of the protein quality control systems, their role in CMT1, and potential treatment strategies to restore proteostasis.
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Affiliation(s)
- Karen Libberecht
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.
| | - Tim Vangansewinkel
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium; UHasselt, Biomedical Research Institute (BIOMED), Lab for Histology and Regeneration (HISTOREGEN Lab), Diepenbeek, Belgium
| | - Ludo Van Den Bosch
- KU Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute (LBI), Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Ivo Lambrichts
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Histology and Regeneration (HISTOREGEN Lab), Diepenbeek, Belgium
| | - Esther Wolfs
- UHasselt, Biomedical Research Institute (BIOMED), Lab for Functional Imaging & Research on Stem Cells (FIERCELab), Diepenbeek, Belgium.
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2
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Procacci NM, Hastings RL, Aziz AA, Christiansen NM, Zhao J, DeAngeli C, LeBlanc N, Notterpek L, Valdez G, Gould TW. Kir4.1 is specifically expressed and active in non-myelinating Schwann cells. Glia 2023; 71:926-944. [PMID: 36479906 PMCID: PMC9931657 DOI: 10.1002/glia.24315] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022]
Abstract
Non-myelinating Schwann cells (NMSC) play important roles in peripheral nervous system formation and function. However, the molecular identity of these cells remains poorly defined. We provide evidence that Kir4.1, an inward-rectifying K+ channel encoded by the KCNJ10 gene, is specifically expressed and active in NMSC. Immunostaining revealed that Kir4.1 is present in terminal/perisynaptic SCs (TPSC), synaptic glia at neuromuscular junctions (NMJ), but not in myelinating SCs (MSC) of adult mice. To further examine the expression pattern of Kir4.1, we generated BAC transgenic Kir4.1-CreERT2 mice and crossed them to the tdTomato reporter line. Activation of CreERT2 with tamoxifen after the completion of myelination onset led to robust expression of tdTomato in NMSC, including Remak Schwann cells (RSC) along peripheral nerves and TPSC, but not in MSC. In contrast, activating CreERT2 before and during the onset of myelination led to tdTomato expression in NMSC and MSC. These observations suggest that immature SC express Kir4.1, and its expression is then downregulated selectively in myelin-forming SC. In support, we found that while activating CreERT2 induces tdTomato expression in immature SC, it fails to induce tdTomato in MSC associated with sensory axons in culture. NMSC derived from neonatal sciatic nerve were shown to express Kir4.1 and exhibit barium-sensitive inwardly rectifying macroscopic K+ currents. Thus, this study identified Kir4.1 as a potential modulator of immature SC and NMSC function. Additionally, it established a novel transgenic mouse line to introduce or delete genes in NMSC.
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Affiliation(s)
- Nicole M Procacci
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Robert Louis Hastings
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Aamir A Aziz
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Nina M Christiansen
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Jie Zhao
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Claire DeAngeli
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Normand LeBlanc
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Lucia Notterpek
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Thomas W Gould
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada, USA
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3
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Mitra S, Dash R, Munni YA, Selsi NJ, Akter N, Uddin MN, Mazumder K, Moon IS. Natural Products Targeting Hsp90 for a Concurrent Strategy in Glioblastoma and Neurodegeneration. Metabolites 2022; 12:1153. [PMID: 36422293 PMCID: PMC9697676 DOI: 10.3390/metabo12111153] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/16/2022] [Accepted: 11/16/2022] [Indexed: 09/16/2023] Open
Abstract
Glioblastoma multiforme (GBM) is one of the most common aggressive, resistant, and invasive primary brain tumors that share neurodegenerative actions, resembling many neurodegenerative diseases. Although multiple conventional approaches, including chemoradiation, are more frequent in GBM therapy, these approaches are ineffective in extending the mean survival rate and are associated with various side effects, including neurodegeneration. This review proposes an alternative strategy for managing GBM and neurodegeneration by targeting heat shock protein 90 (Hsp90). Hsp90 is a well-known molecular chaperone that plays essential roles in maintaining and stabilizing protein folding to degradation in protein homeostasis and modulates signaling in cancer and neurodegeneration by regulating many client protein substrates. The therapeutic benefits of Hsp90 inhibition are well-known for several malignancies, and recent evidence highlights that Hsp90 inhibitors potentially inhibit the aggressiveness of GBM, increasing the sensitivity of conventional treatment and providing neuroprotection in various neurodegenerative diseases. Herein, the overview of Hsp90 modulation in GBM and neurodegeneration progress has been discussed with a summary of recent outcomes on Hsp90 inhibition in various GBM models and neurodegeneration. Particular emphasis is also given to natural Hsp90 inhibitors that have been evidenced to show dual protection in both GBM and neurodegeneration.
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Affiliation(s)
- Sarmistha Mitra
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| | - Raju Dash
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| | - Yeasmin Akter Munni
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| | - Nusrat Jahan Selsi
- Product Development Department, Popular Pharmaceuticals Ltd., Dhaka 1207, Bangladesh
| | - Nasrin Akter
- Department of Clinical Pharmacy and Molecular Pharmacology, East West University Bangladesh, Dhaka 1212, Bangladesh
| | - Md Nazim Uddin
- Department of Pharmacy, Southern University Bangladesh, Chittagong 4000, Bangladesh
| | - Kishor Mazumder
- Department of Pharmacy, Jashore University of Science and Technology, Jashore 7408, Bangladesh
- School of Optometry and Vision Science, UNSW Medicine, University of New South Wales (UNSW), Sydney, NSW 2052, Australia
| | - Il Soo Moon
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
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Abstract
Demyelinating forms of Charcot-Marie-Tooth disease (CMT) are genetically and phenotypically heterogeneous and result from highly diverse biological mechanisms including gain of function (including dominant negative effects) and loss of function. While no definitive treatment is currently available, rapid advances in defining the pathomechanisms of demyelinating CMT have led to promising pre-clinical studies, as well as emerging clinical trials. Especially promising are the recently completed pre-clinical genetic therapy studies in PMP-22, GJB1, and SH3TC2-associated neuropathies, particularly given the success of similar approaches in humans with spinal muscular atrophy and transthyretin familial polyneuropathy. This article focuses on neuropathies related to mutations in PMP-22, MPZ, and GJB1, which together comprise the most common forms of demyelinating CMT, as well as on select rarer forms for which promising treatment targets have been identified. Clinical characteristics and pathomechanisms are reviewed in detail, with emphasis on therapeutically targetable biological pathways. Also discussed are the challenges facing the CMT research community in its efforts to advance the rapidly evolving biological insights to effective clinical trials. These considerations include the limitations of currently available animal models, the need for personalized medicine approaches/allele-specific interventions for select forms of demyelinating CMT, and the increasing demand for optimal clinical outcome assessments and objective biomarkers.
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Affiliation(s)
- Vera Fridman
- Department of Neurology, University of Colorado Anschutz Medical Campus, 12631 E 17th Avenue, Mailstop B185, Room 5113C, Aurora, CO, 80045, USA.
| | - Mario A Saporta
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, USA
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5
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Bosco L, Falzone YM, Previtali SC. Animal Models as a Tool to Design Therapeutical Strategies for CMT-like Hereditary Neuropathies. Brain Sci 2021; 11:1237. [PMID: 34573256 PMCID: PMC8465478 DOI: 10.3390/brainsci11091237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 09/05/2021] [Accepted: 09/07/2021] [Indexed: 02/07/2023] Open
Abstract
Since ancient times, animal models have provided fundamental information in medical knowledge. This also applies for discoveries in the field of inherited peripheral neuropathies (IPNs), where they have been instrumental for our understanding of nerve development, pathogenesis of neuropathy, molecules and pathways involved and to design potential therapies. In this review, we briefly describe how animal models have been used in ancient medicine until the use of rodents as the prevalent model in present times. We then travel along different examples of how rodents have been used to improve our understanding of IPNs. We do not intend to describe all discoveries and animal models developed for IPNs, but just to touch on a few arbitrary and paradigmatic examples, taken from our direct experience or from literature. The idea is to show how strategies have been developed to finally arrive to possible treatments for IPNs.
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Affiliation(s)
| | | | - Stefano Carlo Previtali
- Institute of Experimental Neurology (INSPE), Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (L.B.); (Y.M.F.)
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6
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Stavrou M, Sargiannidou I, Georgiou E, Kagiava A, Kleopa KA. Emerging Therapies for Charcot-Marie-Tooth Inherited Neuropathies. Int J Mol Sci 2021; 22:6048. [PMID: 34205075 PMCID: PMC8199910 DOI: 10.3390/ijms22116048] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/29/2021] [Accepted: 05/31/2021] [Indexed: 12/12/2022] Open
Abstract
Inherited neuropathies known as Charcot-Marie-Tooth (CMT) disease are genetically heterogeneous disorders affecting the peripheral nerves, causing significant and slowly progressive disability over the lifespan. The discovery of their diverse molecular genetic mechanisms over the past three decades has provided the basis for developing a wide range of therapeutics, leading to an exciting era of finding treatments for this, until now, incurable group of diseases. Many treatment approaches, including gene silencing and gene replacement therapies, as well as small molecule treatments are currently in preclinical testing while several have also reached clinical trial stage. Some of the treatment approaches are disease-specific targeted to the unique disease mechanism of each CMT form, while other therapeutics target common pathways shared by several or all CMT types. As promising treatments reach the stage of clinical translation, optimal outcome measures, novel biomarkers and appropriate trial designs are crucial in order to facilitate successful testing and validation of novel treatments for CMT patients.
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Affiliation(s)
- Marina Stavrou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Elena Georgiou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Alexia Kagiava
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus; (M.S.); (I.S.); (E.G.); (A.K.)
- Center for Neuromuscular Diseases, The Cyprus Institute of Neurology and Genetics, Cyprus School of Molecular Medicine, Nicosia 2371, Cyprus
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7
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Chaudhury S, Keegan BM, Blagg BSJ. The role and therapeutic potential of Hsp90, Hsp70, and smaller heat shock proteins in peripheral and central neuropathies. Med Res Rev 2021; 41:202-222. [PMID: 32844464 PMCID: PMC8485878 DOI: 10.1002/med.21729] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 12/16/2022]
Abstract
Heat shock proteins (Hsps) are molecular chaperones that also play important roles in the activation of the heat shock response (HSR). The HSR is an evolutionary conserved and protective mechanism that is used to counter abnormal physiological conditions, stressors, and disease states, such as those exemplified in cancer and/or neurodegeneration. In normal cells, heat shock factor-1 (HSF-1), the transcription factor that regulates the HSR, remains in a dormant multiprotein complex that is formed upon association with chaperones (Hsp90, Hsp70, etc.), co-chaperones, and client proteins. However, under cellular stress, HSF-1 dissociates from Hsp90 and induces the transcriptional upregulation of Hsp70 to afford protection against the encountered cellular stress. As a consequence of both peripheral and central neuropathies, cellular stress occurs and results in the accumulation of unfolded and/or misfolded proteins, which can be counterbalanced by activation of the HSR. Since Hsp90 is the primary regulator of the HSR, modulation of Hsp90 by small molecules represents an attractive therapeutic approach against both peripheral and central neuropathies.
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Affiliation(s)
- Subhabrata Chaudhury
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, Indiana, USA
| | - Bradley M Keegan
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, Indiana, USA
| | - Brian S J Blagg
- Department of Chemistry and Biochemistry, Warren Family Research Center for Drug Discovery and Development, University of Notre Dame, Notre Dame, Indiana, USA
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8
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Ha N, Choi YI, Jung N, Song JY, Bae DK, Kim MC, Lee YJ, Song H, Kwak G, Jeong S, Park S, Nam SH, Jung S, Choi B. A novel histone deacetylase 6 inhibitor improves myelination of Schwann cells in a model of Charcot-Marie-Tooth disease type 1A. Br J Pharmacol 2020; 177:5096-5113. [PMID: 33460073 PMCID: PMC7589015 DOI: 10.1111/bph.15231] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 07/22/2020] [Accepted: 07/25/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND AND PURPOSE Charcot-Marie-Tooth (CMT) disease is the most common hereditary peripheral neuropathy. CMT type 1A (CMT1A) accounts for approximately 50% of CMT patients and is linked to PMP22 gene duplication. Histone deacetylase-6 (HDAC6) has pleiotropic effects, such as regulating lipid homeostasis and cellular stress. Although HDAC6 has been regarded as a promising drug target for neurodegenerative diseases, its inhibition has not yet been tested in CMT1A. Here we have tested the therapeutic potential of CKD-504, a clinical stage HDAC6 inhibitor, in a mouse model of CMT1A EXPERIMENTAL APPROACH: The potency and selectivity of CKD-504 was evaluated, using a HDAC enzyme panel assay and western blots. The therapeutic potential of CKD-504 was evaluated using behavioural testing and electrophysiological assessments in the C22 mouse model of CMT1A. PMP22 protein expression and aggregation were analysed in mesenchymal stem cell-derived Schwann cells from CMT1A patients and sciatic nerves from C22 mice. KEY RESULTS The HDAC6 inhibitor, CKD-504, modulated molecular chaperon proteins such as HSP90 and HSP70, which are involved in the folding/refolding of proteins such as PMP22. CKD-504 treatment restored myelination in both mesenchymal stem cell-derived Schwann cells from CMT1A patients and sciatic nerves of C22 mice and improved the axonal integrity of the sciatic nerve, leading to behavioural, electrophysiological, and histological improvements in C22 mice. CONCLUSION AND IMPLICATIONS A novel HDAC6 inhibitor, CKD-504, has potent therapeutic efficacy for CMT1A.
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Affiliation(s)
- Nina Ha
- Department of Health Sciences and Technology, SAIHSTSungkyunkwan UniversitySeoulRepublic of Korea
- CKD Research InstituteYonginRepublic of Korea
| | | | - Namhee Jung
- Department of Biochemistry, College of MedicineEwha Womans UniversitySeoulRepublic of Korea
| | | | | | | | | | | | - Geon Kwak
- Department of Health Sciences and Technology, SAIHSTSungkyunkwan UniversitySeoulRepublic of Korea
| | - Soyeon Jeong
- Department of Biochemistry, College of MedicineEwha Womans UniversitySeoulRepublic of Korea
| | - Saeyoung Park
- Department of Biochemistry, College of MedicineEwha Womans UniversitySeoulRepublic of Korea
| | - Soo Hyun Nam
- Department of Neurology, Samsung Medical CenterSungkyunkwan University School of MedicineSeoulRepublic of Korea
| | - Sung‐Chul Jung
- Department of Biochemistry, College of MedicineEwha Womans UniversitySeoulRepublic of Korea
| | - Byung‐Ok Choi
- Department of Health Sciences and Technology, SAIHSTSungkyunkwan UniversitySeoulRepublic of Korea
- Department of Neurology, Samsung Medical CenterSungkyunkwan University School of MedicineSeoulRepublic of Korea
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9
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Thenmozhi R, Lee JS, Park NY, Choi BO, Hong YB. Gene Therapy Options as New Treatment for Inherited Peripheral Neuropathy. Exp Neurobiol 2020; 29:177-188. [PMID: 32624504 PMCID: PMC7344374 DOI: 10.5607/en20004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 04/21/2020] [Accepted: 05/11/2020] [Indexed: 02/06/2023] Open
Abstract
Inherited peripheral neuropathy (IPN) is caused by heterogeneous genetic mutations in more than 100 genes. So far, several treatment options for IPN have been developed and clinically evaluated using small molecules. However, gene therapy-based therapeutic strategies have not been aggressively investigated, likely due to the complexities of inheritance in IPN. Indeed, because the majority of the causative mutations of IPN lead to gain-of-function rather than loss-of-function, developing a therapeutic strategy is more difficult, especially considering gene therapy for genetic diseases began with the simple idea of replacing a defective gene with a functional copy. Recent advances in gene manipulation technology have brought novel approaches to gene therapy and its clinical application for IPN treatment. For example, in addition to the classically used gene replacement for mutant genes in recessively inherited IPN, other techniques including gene addition to modify the disease phenotype, modulations of target gene expression, and techniques to edit mutant genes have been developed and evaluated as potent therapeutic strategies for dominantly inherited IPN. In this review, the current status of gene therapy for IPN and future perspectives will be discussed.
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Affiliation(s)
| | - Ji-Su Lee
- Stem Cell & Regenerative Medicne Institute, Samsung Medical Center, Seoul 06351, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
| | - Na Young Park
- Department of Biochemistry, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Byung-Ok Choi
- Stem Cell & Regenerative Medicne Institute, Samsung Medical Center, Seoul 06351, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.,Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea
| | - Young Bin Hong
- Department of Biochemistry, College of Medicine, Dong-A University, Busan 49201, Korea
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10
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Serfecz J, Bazick H, Al Salihi MO, Turner P, Fields C, Cruz P, Renne R, Notterpek L. Downregulation of the human peripheral myelin protein 22 gene by miR-29a in cellular models of Charcot-Marie-Tooth disease. Gene Ther 2019; 26:455-464. [PMID: 31455873 PMCID: PMC6920087 DOI: 10.1038/s41434-019-0098-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 07/04/2019] [Accepted: 07/10/2019] [Indexed: 12/22/2022]
Abstract
The majority of hereditary neuropathies are caused by duplication of the peripheral myelin protein 22 (PMP22) gene. Therefore, mechanisms to suppress the expression of the PMP22 gene have high therapeutic significance. Here we asked whether the human PMP22 gene is a target for regulation by microRNA 29a (miR-29a). Using bioinformatics, we determined that the human PMP22 gene contains the conserved seed sequence of the miR-29a binding site and this regulatory motif is included in the duplicated region in neuropathic patients. Using luciferase reporter assays in HEK293 cells, we demonstrated that transient transfection of a miR-29a mimic is associated with reduction in PMP22 3'UTR reporter activity. Transfecting normal and humanized transgenic neuropathic mouse Schwann cells with a miR-29a expression plasmid effectively lowered both the endogenous mouse and the transgenic human PMP22 transcripts compared with control vector. In dermal fibroblasts derived from neuropathic patients, ectopic expression of miR-29a led to ~50% reduction in PMP22 mRNA, which corresponded to ~20% decrease in PMP22 protein levels. Significantly, miR-29a-mediated reduction in PMP22 mitigated the reduced mitotic capacity of the neuropathic cells. Together, these results support further testing of miR-29a and/or PMP22-targeting siRNAs as therapeutic agents for correcting the aberrant expression of PMP22 in neuropathic patients.
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Affiliation(s)
- Jacquelyn Serfecz
- Department of Molecular Genetics & Microbiology, College of Medicine University of Florida, Gainesville, FL, 32610, USA
| | - Hannah Bazick
- Department of Neuroscience, College of Medicine University of Florida, Gainesville, FL, 32610, USA
| | - Mohammed Omar Al Salihi
- Department of Neuroscience, College of Medicine University of Florida, Gainesville, FL, 32610, USA
| | - Peter Turner
- Department of Molecular Genetics & Microbiology, College of Medicine University of Florida, Gainesville, FL, 32610, USA
| | - Christopher Fields
- Department of Molecular Genetics & Microbiology, College of Medicine University of Florida, Gainesville, FL, 32610, USA
| | - Pedro Cruz
- Department of Neuroscience, College of Medicine University of Florida, Gainesville, FL, 32610, USA
- Center for Translational Research in Neurodegenerative Disease, College of Medicine University of Florida, Gainesville, FL, 32610, USA
| | - Rolf Renne
- Department of Molecular Genetics & Microbiology, College of Medicine University of Florida, Gainesville, FL, 32610, USA
- UF Health Cancer Center, College of Medicine University of Florida, Gainesville, FL, 32610, USA
| | - Lucia Notterpek
- Department of Neuroscience, College of Medicine University of Florida, Gainesville, FL, 32610, USA.
- Center for Translational Research in Neurodegenerative Disease, College of Medicine University of Florida, Gainesville, FL, 32610, USA.
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11
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Scalia F, Marino Gammazza A, Conway de Macario E, Macario AJL, Cappello F. Myelin Pathology: Involvement of Molecular Chaperones and the Promise of Chaperonotherapy. Brain Sci 2019; 9:brainsci9110297. [PMID: 31671529 PMCID: PMC6896170 DOI: 10.3390/brainsci9110297] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/23/2019] [Accepted: 10/27/2019] [Indexed: 11/27/2022] Open
Abstract
The process of axon myelination involves various proteins including molecular chaperones. Myelin alteration is a common feature in neurological diseases due to structural and functional abnormalities of one or more myelin proteins. Genetic proteinopathies may occur either in the presence of a normal chaperoning system, which is unable to assist the defective myelin protein in its folding and migration, or due to mutations in chaperone genes, leading to functional defects in assisting myelin maturation/migration. The latter are a subgroup of genetic chaperonopathies causing demyelination. In this brief review, we describe some paradigmatic examples pertaining to the chaperonins Hsp60 (HSPD1, or HSP60, or Cpn60) and CCT (chaperonin-containing TCP-1). Our aim is to make scientists and physicians aware of the possibility and advantages of classifying patients depending on the presence or absence of a chaperonopathy. In turn, this subclassification will allow the development of novel therapeutic strategies (chaperonotherapy) by using molecular chaperones as agents or targets for treatment.
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Affiliation(s)
- Federica Scalia
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), University of Palermo, 90127 Palermo, Italy.
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90139 Palermo, Italy.
| | - Antonella Marino Gammazza
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), University of Palermo, 90127 Palermo, Italy.
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90139 Palermo, Italy.
| | - Everly Conway de Macario
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90139 Palermo, Italy.
- Department of Microbiology and Immunology, School of Medicine, University of Maryland at Baltimore-Institute of Marine and Environmental Technology (IMET), Baltimore, MD 21202, USA.
| | - Alberto J L Macario
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90139 Palermo, Italy.
- Department of Microbiology and Immunology, School of Medicine, University of Maryland at Baltimore-Institute of Marine and Environmental Technology (IMET), Baltimore, MD 21202, USA.
| | - Francesco Cappello
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), University of Palermo, 90127 Palermo, Italy.
- Euro-Mediterranean Institute of Science and Technology (IEMEST), 90139 Palermo, Italy.
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12
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Han SH, Yun SH, Shin YK, Park HT, Park JI. Heat Shock Protein 90 is Required for cAMP-Induced Differentiation in Rat Primary Schwann Cells. Neurochem Res 2019; 44:2643-2657. [PMID: 31606837 DOI: 10.1007/s11064-019-02885-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/29/2019] [Accepted: 09/30/2019] [Indexed: 12/12/2022]
Abstract
Schwann cells (SCs) play an important role in producing myelin for rapid neurotransmission in the peripheral nervous system. Activation of the differentiation and myelination processes in SCs requires the expression of a series of transcriptional factors including Sox10, Oct6/Pou3f1, and Egr2/Krox20. However, functional interactions among several transcription factors are poorly defined and the important components of the regulatory network are still unknown. Until now, available evidence suggests that SCs require cAMP signaling to initiate the myelination program. Heat shock protein 90 (Hsp90) is known as a chaperone required to stabilize ErbB2 receptor. In recent years, it was reported that cAMP transactivated the ErbB2/ErbB3 signaling in SCs. However, the relationship between Hsp90 and cAMP-induced differentiation in SCs is undefined. Here we investigated the role of Hsp90 during cAMP-induced differentiation of SCs using Hsp90 inhibitor, geldanamycin and Hsp90 siRNA transfection. Our results showed that dibutyryl-cAMP (db-cAMP) treatment upregulated Hsp90 expression and led to nuclear translocation of Gab1/ERK, the downstream signaling pathway of the ErbB2 signaling mechanism in myelination. The expression of myelin-related genes and nuclear translocation of Gab1/ERK following db-cAMP treatment was inhibited by geldanamycin pretreatment and Hsp90 knockdown. These findings suggest that Hsp90 might play a role in cAMP-induced differentiation via stabilization of ErbB2 and nuclear translocation of Gab1/ERK in SCs.
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Affiliation(s)
- Sang-Heum Han
- Department of Biochemistry, Dong-A University College of Medicine, 32, Daesingongwon-ro, Seo-Gu, Busan, 49201, Republic of Korea.,Peripheral Neuropathy Research Center, Dong-A University, Busan, Republic of Korea
| | - Seong-Hoon Yun
- Department of Biochemistry, Dong-A University College of Medicine, 32, Daesingongwon-ro, Seo-Gu, Busan, 49201, Republic of Korea.,Peripheral Neuropathy Research Center, Dong-A University, Busan, Republic of Korea
| | - Yoon-Kyoung Shin
- Peripheral Neuropathy Research Center, Dong-A University, Busan, Republic of Korea
| | - Hwan-Tae Park
- Peripheral Neuropathy Research Center, Dong-A University, Busan, Republic of Korea. .,Department of Molecular Neuroscience, Dong-A University College of Medicine, 32, Daesingongwon-ro, Seo-Gu, Busan, 49201, Republic of Korea.
| | - Joo-In Park
- Department of Biochemistry, Dong-A University College of Medicine, 32, Daesingongwon-ro, Seo-Gu, Busan, 49201, Republic of Korea. .,Peripheral Neuropathy Research Center, Dong-A University, Busan, Republic of Korea.
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13
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Chittoor-Vinod VG, Bazick H, Todd AG, Falk D, Morelli KH, Burgess RW, Foster TC, Notterpek L. HSP90 Inhibitor, NVP-AUY922, Improves Myelination in Vitro and Supports the Maintenance of Myelinated Axons in Neuropathic Mice. ACS Chem Neurosci 2019; 10:2890-2902. [PMID: 31017387 PMCID: PMC6588339 DOI: 10.1021/acschemneuro.9b00105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
![]()
Hereditary
demyelinating neuropathies linked to peripheral myelin
protein 22 (PMP22) involve the disruption of normal protein trafficking
and are therefore relevant targets for chaperone therapy. Using a
small molecule HSP90 inhibitor, EC137, in cell culture models, we
previously validated the chaperone pathway as a viable target for
therapy development. Here, we tested five commercially available inhibitors
of HSP90 and identified BIIB021 and AUY922 to support Schwann cell
viability and enhance chaperone expression. AUY922 showed higher efficacy,
compared to BIIB021, in enhancing myelin synthesis in dorsal root
ganglion explant cultures from neuropathic mice. For in vivo testing,
we randomly assigned 2–3 month old C22 and 6 week old Trembler
J (TrJ) mice to receive two weekly injections of either vehicle or
AUY922 (2 mg/kg). By the intraperitoneal (i.p.) route, the drug was
well-tolerated by all mice over the 5 month long study, without influence
on body weight or general grooming behavior. AUY922 improved the maintenance
of myelinated nerves of both neuropathic models and attenuated the
decline in rotarod performance and peak muscle force production in
C22 mice. These studies highlight the significance of proteostasis
in neuromuscular function and further validate the HSP90 pathway as
a therapeutic target for hereditary neuropathies.
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Affiliation(s)
- Vinita G. Chittoor-Vinod
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, 1149 Newell Drive, Box 100244, Gainesville, Florida 32610-0244, United States
| | - Hannah Bazick
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, 1149 Newell Drive, Box 100244, Gainesville, Florida 32610-0244, United States
| | - Adrian G. Todd
- Department of Pediatrics, Powell Gene Therapy Center, University of Florida, Gainesville, Florida 32611, United States
| | - Darin Falk
- Department of Pediatrics, Powell Gene Therapy Center, University of Florida, Gainesville, Florida 32611, United States
| | - Kathryn H. Morelli
- The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine 04469, United States
- The Jackson Laboratory, Bar Harbor, Maine 04609, United States
| | - Robert W. Burgess
- The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine 04469, United States
- The Jackson Laboratory, Bar Harbor, Maine 04609, United States
| | - Thomas C. Foster
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, 1149 Newell Drive, Box 100244, Gainesville, Florida 32610-0244, United States
| | - Lucia Notterpek
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, 1149 Newell Drive, Box 100244, Gainesville, Florida 32610-0244, United States
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14
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Zhang X, Li C, Fowler SC, Zhang Z, Blagg BSJ, Dobrowsky RT. Targeting Heat Shock Protein 70 to Ameliorate c-Jun Expression and Improve Demyelinating Neuropathy. ACS Chem Neurosci 2018; 9:381-390. [PMID: 29120605 DOI: 10.1021/acschemneuro.7b00377] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Increased expression of the c-jun transcription factor occurs in a variety of human neuropathies and is critical in promoting Schwann cell (SC) dedifferentiation and loss of the myelinated phenotype. Using cell culture models, we previously identified KU-32 as a novobiocin-based C-terminal heat shock protein 90 (Hsp90) inhibitor that decreased c-jun expression and the extent of demyelination. Additional chemical optimization has yielded KU-596 as a neuroprotective novologue whose mechanistic efficacy to improve a metabolic neuropathy requires the expression of Hsp70. The current study examined whether KU-596 therapy could decrease c-jun expression and improve motor function in an inducible transgenic model of a SC-specific demyelinating neuropathy (MPZ-Raf mice). Treating MPZ-Raf mice with tamoxifen activates the MAPK kinase pathway, increases c-jun expression and produces a profound demyelinating neuropathy characterized by a loss of motor function and paraparesis. KU-596 therapy did not interfere with MAPK activation but reduced c-jun expression, significantly improved motor performance, and ameliorated the extent of peripheral nerve demyelination in both prevention and intervention studies. Hsp70 was necessary for the drug's neuroprotective efficacy since MPZ-Raf × Hsp70 knockout mice did not respond to KU-596 therapy. Collectively, our data indicate that modulating Hsp70 may provide a novel therapeutic approach to attenuate SC c-jun expression and ameliorate the onset of certain demyelinating neuropathies in humans.
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Affiliation(s)
- Xinyue Zhang
- Department
of Pharmacology and Toxicology and ‡Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Chengyuan Li
- Department
of Pharmacology and Toxicology and ‡Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Stephen C. Fowler
- Department
of Pharmacology and Toxicology and ‡Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Zheng Zhang
- Department
of Pharmacology and Toxicology and ‡Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Brian S. J. Blagg
- Department
of Pharmacology and Toxicology and ‡Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
| | - Rick T. Dobrowsky
- Department
of Pharmacology and Toxicology and ‡Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, United States
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15
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Nonclinical data supporting orphan medicinal product designations: lessons from rare neurological conditions. Drug Discov Today 2018; 23:26-48. [DOI: 10.1016/j.drudis.2017.09.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 09/01/2017] [Accepted: 09/27/2017] [Indexed: 12/14/2022]
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16
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Abstract
The chaperome constitutes a broad family of molecular chaperones and co-chaperones that facilitate the folding, refolding, and degradation of the proteome. Heat shock protein 90 (Hsp90) promotes the folding of numerous oncoproteins to aid survival of malignant phenotypes, and small molecule inhibitors of the Hsp90 chaperone complex offer a viable approach to treat certain cancers. One therapeutic attribute of this approach is the selectivity of these molecules to target high affinity oncogenic Hsp90 complexes present in tumor cells, which are absent in nontransformed cells. This selectivity has given rise to the idea that disease may contribute to forming a stress chaperome that is functionally distinct in its ability to interact with small molecule Hsp90 modulators. Consistent with this premise, modulating Hsp90 improves clinically relevant endpoints of diabetic peripheral neuropathy but has little impact in nondiabetic nerve. The concept of targeting the "diabetic chaperome" to treat diabetes and its complications is discussed.
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Affiliation(s)
- Rick T Dobrowsky
- Department of Pharmacology and Toxicology, The University of Kansas, 5064 Malott Hall 1251 Wescoe Hall Dr., Lawrence, KS, 66045, USA.
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17
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Sociali G, Visigalli D, Prukop T, Cervellini I, Mannino E, Venturi C, Bruzzone S, Sereda MW, Schenone A. Tolerability and efficacy study of P2X7 inhibition in experimental Charcot-Marie-Tooth type 1A (CMT1A) neuropathy. Neurobiol Dis 2016; 95:145-57. [PMID: 27431093 DOI: 10.1016/j.nbd.2016.07.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 06/24/2016] [Accepted: 07/13/2016] [Indexed: 12/24/2022] Open
Abstract
Charcot-Marie-Tooth 1A (CMT1A) is a demyelinating hereditary neuropathy for which pharmacological treatments are not yet available. An abnormally high intracellular Ca(2+) concentration was observed in Schwann cells (SC) from CMT1A rats, caused by the PMP22-mediated overexpression of the P2X7 purinoceptor. The purpose of this study was to investigate the tolerability and therapeutic potential of a pharmacological antagonist of the P2X7 receptor (A438079) in CMT1A. A438079 ameliorated in vitro myelination of organotypic DRG cultures from CMT1A rats. Furthermore, we performed an experimental therapeutic trial in PMP22 transgenic and in wild-type rats. A preliminary dose-escalation trial showed that 3mg/kg A438079 administered via intraperitoneal injection every 24h for four weeks was well tolerated by wild type and CMT1A rats. Affected rats treated with 3mg/kg A438079 revealed a significant improvement of the muscle strength, when compared to placebo controls. Importantly, histologic analysis revealed a significant increase of the total number of myelinated axons in tibial nerves. Moreover, a significant decrease of the hypermyelination of small caliber axons and a significant increase of the frequency and diameter of large caliber myelinated axons was highlighted. An improved distal motor latencies was recorded, whereas compound muscle action potentials (CMAP) remained unaltered. A438079 reduced the SC differentiation defect in CMT1A rats. These results show that pharmacological inhibition of the P2X7 receptor is well tolerated in CMT1A rats and represents a proof-of-principle that antagonizing this pathway may correct the molecular derangements and improve the clinical phenotype in the CMT1A neuropathy.
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Affiliation(s)
- Giovanna Sociali
- DIMES, Section of Biochemistry, and CEBR, University of Genova, Viale Benedetto XV, 1, 16132, Italy
| | - Davide Visigalli
- DINOGMI and CEBR, University of Genova, Largo P. Daneo 3, 16132 Genova, Italy
| | - Thomas Prukop
- Max Planck Institute of Experimental Medicine, Research Group "Molecular and Translational Neurology", Department of Neurogenetics, Hermann-Rein-Str. 3, 37075 Göttingen, Germany; University Medical Center Göttingen, Institute of Clinical Pharmacology, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Ilaria Cervellini
- Max Planck Institute of Experimental Medicine, Research Group "Molecular and Translational Neurology", Department of Neurogenetics, Hermann-Rein-Str. 3, 37075 Göttingen, Germany
| | - Elena Mannino
- DIMES, Section of Biochemistry, and CEBR, University of Genova, Viale Benedetto XV, 1, 16132, Italy
| | - Consuelo Venturi
- DINOGMI and CEBR, University of Genova, Largo P. Daneo 3, 16132 Genova, Italy
| | - Santina Bruzzone
- DIMES, Section of Biochemistry, and CEBR, University of Genova, Viale Benedetto XV, 1, 16132, Italy.
| | - Michael W Sereda
- Max Planck Institute of Experimental Medicine, Research Group "Molecular and Translational Neurology", Department of Neurogenetics, Hermann-Rein-Str. 3, 37075 Göttingen, Germany; University Medical Center Göttingen, Department of Clinical Neurophysiology, Robert-Koch-Str. 40, 37075 Göttingen, Germany
| | - Angelo Schenone
- DINOGMI and CEBR, University of Genova, Largo P. Daneo 3, 16132 Genova, Italy
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18
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Zhou Y, Notterpek L. Promoting peripheral myelin repair. Exp Neurol 2016; 283:573-80. [PMID: 27079997 DOI: 10.1016/j.expneurol.2016.04.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/30/2016] [Accepted: 04/06/2016] [Indexed: 01/08/2023]
Abstract
Compared to the central nervous system (CNS), peripheral nerves have a remarkable ability to regenerate and remyelinate. This regenerative capacity to a large extent is dependent on and supported by Schwann cells, the myelin-forming glial cells of the peripheral nervous system (PNS). In a variety of paradigms, Schwann cells are critical in the removal of the degenerated tissue, which is followed by remyelination of newly-regenerated axons. This unique plasticity of Schwann cells has been the target of myelin repair strategies in acute injuries and chronic diseases, such as hereditary demyelinating neuropathies. In one approach, the endogenous regenerative capacity of Schwann cells is enhanced through interventions such as exercise, electrical stimulation or pharmacological means. Alternatively, Schwann cells derived from healthy nerves, or engineered from different tissue sources have been transplanted into the PNS to support remyelination. These transplant approaches can then be further enhanced by exercise and/or electrical stimulation, as well as by the inclusion of biomaterial engineered to support glial cell viability and neurite extension. Advances in our basic understanding of peripheral nerve biology, as well as biomaterial engineering, will further improve the functional repair of myelinated peripheral nerves.
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Affiliation(s)
- Ye Zhou
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, United States
| | - Lucia Notterpek
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, United States.
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19
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Chittoor-Vinod VG, Lee S, Judge SM, Notterpek L. Inducible HSP70 is critical in preventing the aggregation and enhancing the processing of PMP22. ASN Neuro 2015; 7:7/1/1759091415569909. [PMID: 25694550 PMCID: PMC4342366 DOI: 10.1177/1759091415569909] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Chaperones, also called heat shock proteins (HSPs), transiently interact with proteins to aid their folding, trafficking, and degradation, thereby directly influencing the transport of newly synthesized molecules. Induction of chaperones provides a potential therapeutic approach for protein misfolding disorders, such as peripheral myelin protein 22 (PMP22)-associated peripheral neuropathies. Cytosolic aggregates of PMP22, linked with a demyelinating Schwann cell phenotype, result in suppression of proteasome activity and activation of proteostatic mechanisms, including the heat shock pathway. Although the beneficial effects of chaperones in preventing the aggregation and improving the trafficking of PMP22 have been repeatedly observed, the requirement for HSP70 in events remains elusive. In this study, we show that activation of the chaperone pathway in fibroblasts from PMP22 duplication-associated Charcot–Marie–Tooth disease type 1A patient with an FDA-approved small molecule increases HSP70 expression and attenuates proteasome dysfunction. Using cells from an HSP70.1/3−/− (inducible HSP70) mouse model, we demonstrate that under proteotoxic stress, this chaperone is critical in preventing the aggregation of PMP22, and this effect is aided by macroautophagy. When examined at steady-state, HSP70 appears to play a minor role in the trafficking of wild-type-PMP22, while it is crucial for preventing the buildup of the aggregation-prone Trembler-J-PMP22. HSP70 aids the processing of Trembler-J-PMP22 through the Golgi and its delivery to lysosomes via Rab7-positive vesicles. Together, these results demonstrate a key role for inducible HSP70 in aiding the processing and hindering the accumulation of misfolded PMP22, which in turn alleviates proteotoxicity within the cells.
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Affiliation(s)
- Vinita G Chittoor-Vinod
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Sooyeon Lee
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
| | - Sarah M Judge
- Department of Physical Therapy, College of Public Health & Health Professions, University of Florida, Gainesville, FL, USA
| | - Lucia Notterpek
- Departments of Neuroscience and Neurology, College of Medicine, McKnight Brain Institute, University of Florida, Gainesville, FL, USA
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20
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Abstract
Haploinsufficiency of peripheral myelin protein 22 (PMP22) causes hereditary neuropathy with liability to pressure palsies, a peripheral nerve lesion induced by minimal trauma or compression. As PMP22 is localized to cholesterol-enriched membrane domains that are closely linked with the underlying actin network, we asked whether the myelin instability associated with PMP22 deficiency could be mediated by involvement of the protein in actin-dependent cellular functions and/or lipid raft integrity. In peripheral nerves and cells from mice with PMP22 deletion, we assessed the organization of filamentous actin (F-actin), and actin-dependent cellular functions. Using in vitro models, we discovered that, in the absence of PMP22, the migration and adhesion capacity of Schwann cells and fibroblasts are similarly impaired. Furthermore, PMP22-deficient Schwann cells produce shortened myelin internodes, and display compressed axial cell length and collapsed lamellipodia. During early postnatal development, F-actin-enriched Schmidt-Lanterman incisures do not form properly in nerves from PMP22(-/-) mice, and the expression and localization of molecules associated with uncompacted myelin domains and lipid rafts, including flotillin-1, cholesterol, and GM1 ganglioside, are altered. In addition, we identified changes in the levels and distribution of cholesterol and ApoE when PMP22 is absent. Significantly, cholesterol supplementation of the culture medium corrects the elongation and migration deficits of PMP22(-/-) Schwann cells, suggesting that the observed functional impairments are directly linked with cholesterol deficiency of the plasma membrane. Our findings support a novel role for PMP22 in the linkage of the actin cytoskeleton with the plasma membrane, likely through regulating the cholesterol content of lipid rafts.
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21
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Xu G, Fromholt S, Ayers JI, Brown H, Siemienski Z, Crosby KW, Mayer CA, Janus C, Borchelt DR. Substantially elevating the levels of αB-crystallin in spinal motor neurons of mutant SOD1 mice does not significantly delay paralysis or attenuate mutant protein aggregation. J Neurochem 2015; 133:452-64. [PMID: 25557022 DOI: 10.1111/jnc.13022] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 12/10/2014] [Accepted: 12/16/2014] [Indexed: 12/14/2022]
Abstract
There has been great interest in enhancing endogenous protein maintenance pathways such as the heat-shock chaperone response, as it is postulated that enhancing clearance of misfolded proteins could have beneficial disease modifying effects in amyotrophic lateral sclerosis and other neurodegenerative disorders. In cultured cell models of mutant SOD1 aggregation, co-expression of αB-crystallin (αB-crys) has been shown to inhibit the formation of detergent-insoluble forms of mutant protein. Here, we describe the generation of a new line of transgenic mice that express αB-crys at > 6-fold the normal level in spinal cord, with robust increases in immunoreactivity throughout the spinal cord grey matter and, specifically, in spinal motor neurons. Surprisingly, spinal cords of mice expressing αB-crys alone contained 20% more motor neurons per section than littermate controls. Raising αB-crys by these levels in mice transgenic for either G93A or L126Z mutant SOD1 had no effect on the age at which paralysis developed. In the G93A mice, which showed the most robust degree of motor neuron loss, the number of these cells declined by the same proportion as in mice expressing the mutant SOD1 alone. In paralyzed bigenic mice, the levels of detergent-insoluble, misfolded, mutant SOD1 were similar to those of mice expressing mutant SOD1 alone. These findings indicate that raising the levels of αB-crys in spinal motor neurons by 6-fold does not produce the therapeutic effects predicted by cell culture models of mutant SOD1 aggregation. Enhancing the protein chaperone function may present a therapeutic approach to amyotrophic lateral sclerosis caused by mutations in SOD1, and other neurodegenerative disorders characterized by cytosolic protein aggregation. Previous studies in cell models suggested that the chaperone known as αB-crystallin (αB-crys) can prevent mutant SOD1 aggregation. We report that transgenic expression of αB-crys at > 6-fold the normal level in spinal cords of mice expressing mutant SOD1 produces no therapeutic benefit.
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Affiliation(s)
- Guilian Xu
- Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
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22
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Chumakov I, Milet A, Cholet N, Primas G, Boucard A, Pereira Y, Graudens E, Mandel J, Laffaire J, Foucquier J, Glibert F, Bertrand V, Nave KA, Sereda MW, Vial E, Guedj M, Hajj R, Nabirotchkin S, Cohen D. Polytherapy with a combination of three repurposed drugs (PXT3003) down-regulates Pmp22 over-expression and improves myelination, axonal and functional parameters in models of CMT1A neuropathy. Orphanet J Rare Dis 2014; 9:201. [PMID: 25491744 PMCID: PMC4279797 DOI: 10.1186/s13023-014-0201-x] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 11/24/2014] [Indexed: 11/24/2022] Open
Abstract
Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common inherited sensory and motor peripheral neuropathy. It is caused by PMP22 overexpression which leads to defects of peripheral myelination, loss of long axons, and progressive impairment then disability. There is no treatment available despite observations that monotherapeutic interventions slow progression in rodent models. We thus hypothesized that a polytherapeutic approach using several drugs, previously approved for other diseases, could be beneficial by simultaneously targeting PMP22 and pathways important for myelination and axonal integrity. A combination of drugs for CMT1A polytherapy was chosen from a group of authorised drugs for unrelated diseases using a systems biology approach, followed by pharmacological safety considerations. Testing and proof of synergism of these drugs were performed in a co-culture model of DRG neurons and Schwann cells derived from a Pmp22 transgenic rat model of CMT1A. Their ability to lower Pmp22 mRNA in Schwann cells relative to house-keeping genes or to a second myelin transcript (Mpz) was assessed in a clonal cell line expressing these genes. Finally in vivo efficacy of the combination was tested in two models: CMT1A transgenic rats, and mice that recover from a nerve crush injury, a model to assess neuroprotection and regeneration. Combination of (RS)-baclofen, naltrexone hydrochloride and D-sorbitol, termed PXT3003, improved myelination in the Pmp22 transgenic co-culture cellular model, and moderately down-regulated Pmp22 mRNA expression in Schwannoma cells. In both in vitro systems, the combination of drugs was revealed to possess synergistic effects, which provided the rationale for in vivo clinical testing of rodent models. In Pmp22 transgenic CMT1A rats, PXT3003 down-regulated the Pmp22 to Mpz mRNA ratio, improved myelination of small fibres, increased nerve conduction and ameliorated the clinical phenotype. PXT3003 also improved axonal regeneration and remyelination in the murine nerve crush model. Based on these observations in preclinical models, a clinical trial of PTX3003 in CMT1A, a neglected orphan disease, is warranted. If the efficacy of PTX3003 is confirmed, rational polytherapy based on novel combinations of existing non-toxic drugs with pleiotropic effects may represent a promising approach for rapid drug development.
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23
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Jerath NU, Shy ME. Hereditary motor and sensory neuropathies: Understanding molecular pathogenesis could lead to future treatment strategies. Biochim Biophys Acta Mol Basis Dis 2014; 1852:667-78. [PMID: 25108281 DOI: 10.1016/j.bbadis.2014.07.031] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 07/02/2014] [Accepted: 07/30/2014] [Indexed: 10/24/2022]
Abstract
Inherited peripheral neuropathies, like many other degenerative disorders, have been challenging to treat. At this point, there is little specific therapy for the inherited neuropathies other than genetic counseling as well as symptomatic treatment and rehabilitation. In the past, ascorbic acid, progesterone antagonists, and subcutaneous neurotrophin-3 (NT3) injections have demonstrated improvement in animal models of CMT 1A, the most common inherited neuropathy, but have failed to translate any effect in humans. Given the difficulty in treatment, it is important to understand the molecular pathogenesis of hereditary neuropathies in order to strategize potential future therapies. The hereditary neuropathies are in an era of molecular insight and over the past 20 years, more than 78 subtypes of Charcot Marie Tooth disease (CMT) have been identified and extensively studied to understand the biological pathways in greater detail. Next generation molecular sequencing has also improved the diagnosis as well as the understanding of CMT. A greater understanding of the molecular pathways will help pave the way to future therapeutics of CMT. This article is part of a Special Issue entitled: Neuromuscular Diseases: Pathology and Molecular Pathogenesis.
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Affiliation(s)
- Nivedita U Jerath
- University of Iowa, Carver College of Medicine, Department of Neurology, 200 Hawkins Drive, Iowa City, IA 52242, USA
| | - Michael E Shy
- University of Iowa, Carver College of Medicine, Department of Neurology, 200 Hawkins Drive, Iowa City, IA 52242, USA.
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24
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25
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Biochemical characterization of protein quality control mechanisms during disease progression in the C22 mouse model of CMT1A. ASN Neuro 2013; 5:e00128. [PMID: 24175617 PMCID: PMC3848555 DOI: 10.1042/an20130024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Charcot–Marie–Tooth disease type 1A (CMT1A) is a hereditary demyelinating neuropathy linked with duplication of the peripheral myelin protein 22 (PMP22) gene. Transgenic C22 mice, a model of CMT1A, display many features of the human disease, including slowed nerve conduction velocity and demyelination of peripheral nerves. How overproduction of PMP22 leads to compromised myelin and axonal pathology is not fully understood, but likely involves subcellular alterations in protein homoeostatic mechanisms within affected Schwann cells. The subcellular response to abnormally localized PMP22 includes the recruitment of the ubiquitin–proteasome system (UPS), autophagosomes and heat-shock proteins (HSPs). Here we assessed biochemical markers of these protein homoeostatic pathways in nerves from PMP22-overexpressing neuropathic mice between the ages of 2 and 12 months to ascertain their potential contribution to disease progression. In nerves of 3-week-old mice, using endoglycosidases and Western blotting, we found altered processing of the exogenous human PMP22, an abnormality that becomes more prevalent with age. Along with the ongoing accrual of misfolded PMP22, the activity of the proteasome becomes compromised and proteins required for autophagy induction and lysosome biogenesis are up-regulated. Moreover, cytosolic chaperones are consistently elevated in nerves from neuropathic mice, with the most prominent change in HSP70. The gradual alterations in protein homoeostatic response are accompanied by Schwann cell de-differentiation and macrophage infiltration. Together, these results show that while subcellular protein quality control mechanisms respond appropriately to the presence of the overproduced PMP22, with aging they are unable to prevent the accrual of misfolded proteins. In peripheral nerves of neuropathic C22 mice the frequency of cytosolic PMP22 aggregates increases with age, which elicits a response from protein quality control mechanisms. The combined effects of aging and neuropathic genotype exacerbate disease progression leading to nerve defects.
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Long-term analyses of innervation and neuromuscular integrity in the Trembler-J mouse model of Charcot-Marie-Tooth disease. J Neuropathol Exp Neurol 2013; 72:942-54. [PMID: 24042197 DOI: 10.1097/nen.0b013e3182a5f96e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
A large fraction of hereditary demyelinating neuropathies, classified as Charcot-Marie-Tooth disease type 1A, is associated with misexpression of peripheral myelin protein 22. In this study, we characterized morphologic and biochemical changes that occur with diseaseprogression in neuromuscular tissue of Trembler-J mice, a spontaneous rodent model of Charcot-Marie-Tooth disease type 1A. Using age-matched, 2- and 10-month-old, wild-type and Trembler-J mice, we observed neuromuscular deficits that progress from distal to proximal regions. The impairments in motor performance are underlined by degenerative events at distal nerve segments and structural alterations at nerve-muscle synapses. Furthermore, skeletal muscle of affected mice showed reduced myofiber diameter, increased expression of the muscle atrophy marker muscle ring-finger protein 1, and fiber type switching. A dietary intervention of intermittent fasting attenuated these progressive changes and supported distal nerve myelination and neuromuscular junction integrity. In addition to the well-characterized demyelination aspects of this model, our investigations identified distinct degenerative events in distal nerves and muscle of affected neuropathic mice. Therefore, therapeutic studies aimed at slowing or reversing the neuropathic features of these disorders should include the examination of muscle tissue, as well as neuromuscular contact sites.
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Okamoto Y, Pehlivan D, Wiszniewski W, Beck CR, Snipes GJ, Lupski JR, Khajavi M. Curcumin facilitates a transitory cellular stress response in Trembler-J mice. Hum Mol Genet 2013; 22:4698-705. [PMID: 23847051 DOI: 10.1093/hmg/ddt318] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
We have previously shown that oral administration of curcumin significantly decreases the percentage of apoptotic Schwann cells and partially mitigates the severe neuropathy phenotype of the Trembler-J (Tr-J) mouse model in a dose-dependent manner. Here we compared the gene expression in sciatic nerves of 2-week-old pups and adult Tr-J with the same age groups of wild-type mice and found a significant increase in gene expression for hypoxia, inflammatory response and heat-shock proteins, the latter specifically the Hsp70 family, in Tr-J mice. We also detected an activation of different branches of unfolded protein responses (UPRs) in Tr-J mice. Administering curcumin results in lower expression of UPR markers suggesting it relieves endoplasmic reticulum (ER) cell stress sensors in sciatic nerves of Tr-J mice while the level of heat-shock proteins stays comparable to untreated Tr-J mice. We further tested if Hsp70 levels could influence the severity of the Tr-J neuropathy. Notably, reduced dosage of the Hsp70 strongly potentiates the severity of the Tr-J neuropathy, though the absence of Hsp70 had little effect in wild-type mice. In aggregate, these data provide further insights into the pathological disease mechanisms caused by myelin gene mutations and further support the exploration of curcumin as a therapeutic approach for selected forms of inherited neuropathy and potentially for other genetic diseases due to ER-retained mutants.
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Hamilton RT, Bhattacharya A, Walsh ME, Shi Y, Wei R, Zhang Y, Rodriguez KA, Buffenstein R, Chaudhuri AR, Van Remmen H. Elevated protein carbonylation, and misfolding in sciatic nerve from db/db and Sod1(-/-) mice: plausible link between oxidative stress and demyelination. PLoS One 2013; 8:e65725. [PMID: 23750273 PMCID: PMC3672154 DOI: 10.1371/journal.pone.0065725] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 04/27/2013] [Indexed: 11/19/2022] Open
Abstract
Diabetic peripheral polyneuropathy is associated with decrements in motor/sensory neuron myelination, nerve conduction and muscle function; however, the mechanisms of reduced myelination in diabetes are poorly understood. Chronic elevation of oxidative stress may be one of the potential determinants for demyelination as lipids and proteins are important structural constituents of myelin and highly susceptible to oxidation. The goal of the current study was to determine whether there is a link between protein oxidation/misfolding and demyelination. We chose two distinct models to test our hypothesis: 1) the leptin receptor deficient mouse (dbdb) model of diabetic polyneuropathy and 2) superoxide dismutase 1 knockout (Sod1(-/-) ) mouse model of in vivo oxidative stress. Both experimental models displayed a significant decrement in nerve conduction, increase in tail distal motor latency as well as reduced myelin thickness and fiber/axon diameter. Further biochemical studies demonstrated that oxidative stress is likely to be a potential key player in the demyelination process as both models exhibited significant elevation in protein carbonylation and alterations in protein conformation. Since peripheral myelin protein 22 (PMP22) is a key component of myelin sheath and has been found mutated and aggregated in several peripheral neuropathies, we predicted that an increase in carbonylation and aggregation of PMP22 may be associated with demyelination in dbdb mice. Indeed, PMP22 was found to be carbonylated and aggregated in sciatic nerves of dbdb mice. Sequence-driven hydropathy plot analysis and in vitro oxidation-induced aggregation of purified PMP22 protein supported the premise for oxidation-dependent aggregation of PMP22 in dbdb mice. Collectively, these data strongly suggest for the first time that oxidation-mediated protein misfolding and aggregation of key myelin proteins may be linked to demyelination and reduced nerve conduction in peripheral neuropathies.
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Affiliation(s)
- Ryan T. Hamilton
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
| | - Arunabh Bhattacharya
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
| | - Michael E. Walsh
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Yun Shi
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
| | - Rochelle Wei
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
| | - Yiqiang Zhang
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
| | - Karl A. Rodriguez
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
| | - Rochelle Buffenstein
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
| | - Asish R. Chaudhuri
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
- Geriatric Research Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
- * E-mail: (ARC); (HV)
| | - Holly Van Remmen
- Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Physiology, University of Texas Health Science Center, San Antonio, Texas, United States of America
- Sam and Ann Barshop Institute for Longevity and Aging Studies, San Antonio, Texas, United States of America
- Geriatric Research Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas, United States of America
- * E-mail: (ARC); (HV)
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D'Antonio M, Musner N, Scapin C, Ungaro D, Del Carro U, Ron D, Feltri ML, Wrabetz L. Resetting translational homeostasis restores myelination in Charcot-Marie-Tooth disease type 1B mice. ACTA ACUST UNITED AC 2013; 210:821-38. [PMID: 23547100 PMCID: PMC3620355 DOI: 10.1084/jem.20122005] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Reduction of the CHOP target Gadd34 restores motor function in P0S63del mice with demyelinating neuropathy. P0 glycoprotein is an abundant product of terminal differentiation in myelinating Schwann cells. The mutant P0S63del causes Charcot-Marie-Tooth 1B neuropathy in humans, and a very similar demyelinating neuropathy in transgenic mice. P0S63del is retained in the endoplasmic reticulum of Schwann cells, where it promotes unfolded protein stress and elicits an unfolded protein response (UPR) associated with translational attenuation. Ablation of Chop, a UPR mediator, from S63del mice completely rescues their motor deficit and reduces active demyelination by half. Here, we show that Gadd34 is a detrimental effector of CHOP that reactivates translation too aggressively in myelinating Schwann cells. Genetic or pharmacological limitation of Gadd34 function moderates translational reactivation, improves myelination in S63del nerves, and reduces accumulation of P0S63del in the ER. Resetting translational homeostasis may provide a therapeutic strategy in tissues impaired by misfolded proteins that are synthesized during terminal differentiation.
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Affiliation(s)
- Maurizio D'Antonio
- Division of Genetics and Cell Biology and 2 Division of Neuroscience, San Raffaele Scientific Institute, DIBIT, 20132 Milan, Italy
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Dietary restriction supports peripheral nerve health by enhancing endogenous protein quality control mechanisms. Exp Gerontol 2012; 48:1085-90. [PMID: 23267845 DOI: 10.1016/j.exger.2012.12.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 12/07/2012] [Accepted: 12/17/2012] [Indexed: 01/07/2023]
Abstract
The peripheral nervous system (PNS) comprises of an extensive network of connections that convey information between the central nervous system (CNS) and peripheral organs. Long myelinated nerve fibers are particularly susceptible to age-related changes, as maintenance of the insulating glial membrane requires extensive synthesis and processing of many proteins. In rodent models, peripheral demyelination caused by genetic risk factors or by normal aging are attenuated by intermittent fasting (IF) or calorie restriction (CR) supporting a role for dietary intervention in preserving neural function. This review will summarize recent studies examining mechanisms by which life-long CR or extended IF supports peripheral nerve health.
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Induction of heat shock protein 70 (Hsp70) prevents neuregulin-induced demyelination by enhancing the proteasomal clearance of c-Jun. ASN Neuro 2012; 4:e00102. [PMID: 23240583 PMCID: PMC3517131 DOI: 10.1042/20120047] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Modulating molecular chaperones is emerging as an attractive approach to treat neurodegenerative diseases associated with protein aggregation, DPN (diabetic peripheral neuropathy) and possibly, demyelinating neuropathies. KU-32 [N-(7-((2R,3R,4S,5R)-3,4-dihydroxy-5-methoxy-6,6-dimethyl-tetrahydro-2H-pyran-2-yloxy)-8-methyl-2-oxo-2H-chromen-3-yl)acetamide] is a small molecule inhibitor of Hsp90 (heat shock protein 90) and reverses sensory deficits associated with myelinated fibre dysfunction in DPN. Additionally, KU-32 prevented the loss of myelinated internodes induced by treating myelinated SC (Schwann cell)-DRG (dorsal root ganglia) sensory neuron co-cultures with NRG1 (neuregulin-1 Type 1). Since KU-32 decreased NRG1-induced demyelination in an Hsp70-dependent manner, the goal of the current study was to clarify how Hsp70 may be mechanistically linked to preventing demyelination. The activation of p42/p44 MAPK (mitogen-activated protein kinase) and induction of the transcription factor c-Jun serve as negative regulators of myelination. NRG1 activated MAPK, induced c-Jun expression and promoted a loss of myelin segments in DRG explants isolated from both WT (wild-type) and Hsp70 KO (knockout) mice. Although KU-32 did not block the activation of MAPK, it blocked c-Jun induction and protected against a loss of myelinated segments in WT mice. In contrast, KU-32 did not prevent the NRG1-dependent induction of c-Jun and loss of myelin segments in explants from Hsp70 KO mice. Overexpression of Hsp70 in myelinated DRG explants prepared from WT or Hsp70 KO mice was sufficient to block the induction of c-Jun and the loss of myelin segments induced by NRG1. Lastly, inhibiting the proteasome prevented KU-32 from decreasing c-Jun levels. Collectively, these data support that Hsp70 induction is sufficient to prevent NRG1-induced demyelination by enhancing the proteasomal degradation of c-Jun.
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Fledrich R, Stassart RM, Sereda MW. Murine therapeutic models for Charcot-Marie-Tooth (CMT) disease. Br Med Bull 2012; 102:89-113. [PMID: 22551516 DOI: 10.1093/bmb/lds010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
INTRODUCTION OR BACKGROUND Charcot-Marie-Tooth (CMT) disease represents a broad group of inherited motor and sensory neuropathies which can originate from various genetic aberrations, e.g. mutations, deletions and duplications. SOURCES OF DATA We performed a literature review on murine animal models of CMT disease with regard to experimental therapeutic approaches. Hereby, we focussed on the demyelinating subforms of CMT (CMT1). PubMed items were CMT, animal model, demyelination and therapy. AREAS OF AGREEMENT Patients affected by CMT suffer from slowly progressive, distally pronounced muscle atrophy caused by an axonal loss. The disease severity is highly variable and impairments may result in wheelchair boundness. No therapy is available yet. AREAS OF CONTROVERSY Numerous rodent models for the various CMT subtypes are available today. The selection of the correct animal model for the specific CMT subtype provides an important prerequisite for the successful translation of experimental findings in patients. GROWING POINTS Despite more than 20 years of remarkable progress in CMT research, the disease is still left untreatable. There is a growing number of experimental therapeutic strategies that may be translated into future clinical trials in patients with CMT. AREAS TIMELY FOR DEVELOPING RESEARCH The slow disease progression and insensitive outcome measures hamper clinical therapy trials in CMT. Biomarkers may provide powerful tools to monitor therapeutic efficacy. Recently, we have shown that transcriptional profiling can be utilized to assess and predict the disease severity in a transgenic rat model and in affected humans.
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Affiliation(s)
- Robert Fledrich
- Research Group 'Molecular and Translational Neurology', Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
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Callizot N, Combes M, Steinschneider R, Poindron P. A new long term in vitro model of myelination. Exp Cell Res 2011; 317:2374-83. [PMID: 21777582 DOI: 10.1016/j.yexcr.2011.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/30/2011] [Accepted: 07/03/2011] [Indexed: 11/19/2022]
Abstract
Besides in vivo models, co-cultures systems making use of Rat dorsal root ganglion explants/Schwann cells (SC) are widely used to essentially study myelination in vitro. In the case of animal models of demyelinating diseases, it is expected to reproduce a pathological process; conversely the co-cultures are primarily developed to study the myelination process and in the aim to use them to replace animals in experiences of myelin destruction or functional disturbances. We describe (in terms of protein expression kinetic) a new in vitro model of sensory neurons/SC co-cultures presenting the following advantages: both sensory neurons and SC originate from the same individual; sensory neurons and SC being dissociated, they can be co-cultured in monolayer, allowing an easier microscope observation; the co-culture can be maintained in a serum-free medium for at less three months, allowing kinetic studies of myelin formation both at a molecular and cellular level. Optimizing culture conditions permits to use 96-well culture plates; image analyses conducted with an automatic image analyzer allows rapid, accurate and quantitative expression of results. Finally, this system was proved by measuring the apparition of myelin protein to mimic in vitro the physiological process of in vivo myelination.
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Affiliation(s)
- Noelle Callizot
- Neuron Experts SAS, Faculté de Médecine Nord, 51 Boulevard Pierre Dramard, Marseille Cedex 20, France.
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Verrier JD, Semple-Rowland S, Madorsky I, Papin JE, Notterpek L. Reduction of Dicer impairs Schwann cell differentiation and myelination. J Neurosci Res 2011; 88:2558-68. [PMID: 20648646 DOI: 10.1002/jnr.22418] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The process of Schwann cell myelination requires precisely coordinated gene expression. At the onset of myelination, there is an increase in the expression of differentiation-promoting transcription factors that regulate key Schwann cell genes. Further control of myelin gene expression occurs at the posttranscriptional level and, in part, is mediated by RNA binding proteins and micro-RNAs (miRNAs). miRNAs are small, endogenously derived RNA molecules that repress gene expression by specifically binding to their mRNA targets. In the experiments described here, we tested whether miRNAs were essential in controlling myelination by reducing the levels of Dicer, an essential endoribonuclease in miRNA biogenesis. We decreased the expression of Dicer by about 60% within Schwann cells using a lentiviral vector expressing an shRNA against Dicer. The reduced levels of Dicer led to a decrease in the steady-state expression of selected miRNAs and of the transcription factors Oct6 and Egr2/Krox20, both of which are critical for Schwann cells differentiation and myelination. In contrast, the levels of c-jun and Sox2 were up-regulated by the reduction in Dicer and were associated with an increase in Schwann cell proliferation. In dorsal root ganglion cocultures, Schwann cells transduced with Dicer shRNA synthesized less myelin, which was accompanied by significant reductions in the levels of myelin basic protein and protein zero. These findings support a critical role for Dicer and miRNAs in Schwann cell differentiation and myelination.
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Affiliation(s)
- Jonathan D Verrier
- Department of Neuroscience, College of Medicine, McKnight Brain Institute, University of Florida, Gainesville, Florida 32610-0244, USA
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Rapamycin activates autophagy and improves myelination in explant cultures from neuropathic mice. J Neurosci 2010; 30:11388-97. [PMID: 20739560 DOI: 10.1523/jneurosci.1356-10.2010] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Misexpression and cytosolic retention of peripheral myelin protein 22 (PMP22) within Schwann cells (SCs) is associated with a genetically heterogeneous group of demyelinating peripheral neuropathies. PMP22 overproducer C22 and spontaneous mutant Trembler J (TrJ) mice display neuropathic phenotypes and affected nerves contain abnormally localized PMP22. Nutrient deprivation-induced autophagy is able to suppress the formation of PMP22 aggregates in a toxin-induced cellular model, and improve locomotor performance and myelination in TrJ mice. As a step toward therapies, we assessed whether pharmacological activation of autophagy by rapamycin (RM) could facilitate the processing of PMP22 within neuropathic SCs and enhance their capacity to myelinate peripheral axons. Exposure of mouse SCs to RM induced autophagy in a dose- and time-dependent manner and decreased the accumulation of poly-ubiquitinated substrates. The treatment of myelinating dorsal root ganglion (DRG) explant cultures from neuropathic mice with RM (25 nm) improved the processing of PMP22 and increased the abundance and length of myelin internodes, as well as the expression of myelin proteins. Notably, RM is similarly effective in both the C22 and TrJ model, signifying that the benefit overlaps among distinct genetic models of PMP22 neuropathies. Furthermore, lentivirus-mediated shRNA knockdown of the autophagy-related gene 12 (Atg12) abolished the activation of autophagy and the increase in myelin proteins, demonstrating that autophagy is critical for the observed improvement. Together, these results support the potential use of RM and other autophagy-enhancing compounds as therapeutic agents for PMP22-associated demyelinating neuropathies.
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Abstract
The capacity to fold proteins properly is fundamental for cell survival. Secreted and transmembrane proteins are synthesized in the endoplasmic reticulum (ER), an organelle that has the ability to discriminate between native and nonnative proteins, in a process called protein quality control. When folding is not properly achieved, misfolded proteins can accumulate. The terminally misfolded proteins are typically retrotranslocated into the cytoplasm for degradation by the proteasome, in a process known as endoplasmic reticulum-associated degradation. However, if the degradation is insufficient, accumulation of abnormal proteins in the ER activates the unfolded protein response (UPR), a complex set of new signals aimed to reduce further the load of abnormal protein in the ER. Massive synthesis of myelin lipids and proteins is necessary to support myelinogenesis. Not surprisingly, therefore, ER stress (including the UPR), the proteasome, and autophagy (lysosomes) have been implicated in myelin disorders, such as Pelizaeus-Merzbacher disease and vanishing white matter disease in the central nervous system and Charcot-Marie-Tooth neuropathies in the peripheral nervous system. Here we discuss recent evidence supporting an important role for ER stress in myelin disorders.
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Abstract
PURPOSE OF REVIEW We review recent advances in Charcot-Marie-Tooth disease (CMT), the most frequent inherited neuromuscular disorder. RECENT FINDINGS During the last year further progresses have occurred in this field and concerned identification of novel mutations in recently identified genes, allowing better definition of associated phenotypes; increased knowledge on pathophysiologic mechanisms of the different CMT types, with the contribution of cellular and animal model studies; studies on the natural history of CMT and attempts at developing appropriate outcome measures to assess disease course and intervention efficacy; trials with ascorbic acid in CMT type 1A; and studies on new possible therapeutic strategies. SUMMARY Such advances have implications on clinical management of CMT and are modifying the clinical approach to CMT, by improving diagnostic tools, allowing better definition of prognosis, and increasing the hope for future effective treatments. Research on CMT is important as is shedding light on important pathways that regulates the normal function of axonal transport, vesicular trafficking, and also revealing new aspects of intracellular organelles' function and interactions.
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Current world literature. Curr Opin Neurol 2009; 22:554-61. [PMID: 19755870 DOI: 10.1097/wco.0b013e3283313b14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Itou J, Suyama M, Imamura Y, Deguchi T, Fujimori K, Yuba S, Kawarabayasi Y, Kawasaki T. Functional and comparative genomics analyses of pmp22 in medaka fish. BMC Neurosci 2009; 10:60. [PMID: 19534778 PMCID: PMC2714311 DOI: 10.1186/1471-2202-10-60] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 06/17/2009] [Indexed: 01/23/2023] Open
Abstract
Background Pmp22, a member of the junction protein family Claudin/EMP/PMP22, plays an important role in myelin formation. Increase of pmp22 transcription causes peripheral neuropathy, Charcot-Marie-Tooth disease type1A (CMT1A). The pathophysiological phenotype of CMT1A is aberrant axonal myelination which induces a reduction in nerve conduction velocity (NCV). Several CMT1A model rodents have been established by overexpressing pmp22. Thus, it is thought that pmp22 expression must be tightly regulated for correct myelin formation in mammals. Interestingly, the myelin sheath is also present in other jawed vertebrates. The purpose of this study is to analyze the evolutionary conservation of the association between pmp22 transcription level and vertebrate myelin formation, and to find the conserved non-coding sequences for pmp22 regulation by comparative genomics analyses between jawed fishes and mammals. Results A transgenic pmp22 over-expression medaka fish line was established. The transgenic fish had approximately one fifth the peripheral NCV values of controls, and aberrant myelination of transgenic fish in the peripheral nerve system (PNS) was observed. We successfully confirmed that medaka fish pmp22 has the same exon-intron structure as mammals, and identified some known conserved regulatory motifs. Furthermore, we found novel conserved sequences in the first intron and 3'UTR. Conclusion Medaka fish undergo abnormalities in the PNS when pmp22 transcription increases. This result indicates that an adequate pmp22 transcription level is necessary for correct myelination of jawed vertebrates. Comparison of pmp22 orthologs between distantly related species identifies evolutionary conserved sequences that contribute to precise regulation of pmp22 expression.
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Affiliation(s)
- Junji Itou
- Department of Radiation Biomedical Science IV, Radiation Biology Center, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
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Madorsky I, Opalach K, Waber A, Verrier JD, Solmo C, Foster T, Dunn WA, Notterpek L. Intermittent fasting alleviates the neuropathic phenotype in a mouse model of Charcot-Marie-Tooth disease. Neurobiol Dis 2009; 34:146-54. [PMID: 19320048 DOI: 10.1016/j.nbd.2009.01.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Charcot-Marie-Tooth type 1A (CMT1A) neuropathies linked to the misexpression of peripheral myelin protein 22 (PMP22) are progressive demyelinating disorders of the peripheral nervous system. In this study we asked whether dietary restriction by intermittent fasting (IF) could alleviate the neuropathic phenotype in the Trembler J (TrJ) mouse model of CMT1A. Our results show that neuropathic mice kept on a five month long IF regimen had improved locomotor performance compared to ad libitum (AL) fed littermates. The functional benefits of this dietary intervention are associated with an increased expression of myelin proteins combined with a thicker myelin sheath, less redundant basal lamina, and a reduction in aberrant Schwann cell proliferation. These morphological improvements are accompanied by a decrease in PMP22 protein aggregates, and enhanced expression of cytosolic chaperones and constituents of the autophagy-lysosomal pathway. These results indicate that dietary restriction is beneficial for peripheral nerve function in TrJ neuropathic mice, as it promotes the maintenance of locomotor performance.
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Affiliation(s)
- Irina Madorsky
- Department of Neuroscience, College of Medicine, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA
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Rangaraju S, Hankins D, Madorsky I, Madorsky E, Lee WH, Carter CS, Leeuwenburgh C, Notterpek L. Molecular architecture of myelinated peripheral nerves is supported by calorie restriction with aging. Aging Cell 2009; 8:178-91. [PMID: 19239416 DOI: 10.1111/j.1474-9726.2009.00460.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Peripheral nerves from aged animals exhibit features of degeneration, including marked fiber loss, morphological irregularities in myelinated axons and notable reduction in the expression of myelin proteins. To investigate how protein homeostatic mechanisms change with age within the peripheral nervous system, we isolated Schwann cells from the sciatic nerves of young and old rats. The responsiveness of cells from aged nerves to stress stimuli is weakened, which in part may account for the observed age-associated alterations in glial and axonal proteins in vivo. Although calorie restriction is known to slow the aging process in the central nervous system, its influence on peripheral nerves has not been investigated in detail. To determine if dietary restriction is beneficial for peripheral nerve health and glial function, we studied sciatic nerves from rats of four distinct ages (8, 18, 29 and 38 months) kept on an ad libitum (AL) or a 40% calorie restricted diet. Age-associated reduction in the expression of the major myelin proteins and widening of the nodes of Ranvier are attenuated by the dietary intervention, which is paralleled with the maintenance of a differentiated Schwann cell phenotype. The improvements in nerve architecture with diet restriction, in part, are underlined by sustained expression of protein chaperones and markers of the autophagy-lysosomal pathway. Together, the in vitro and in vivo results suggest that there might be an age-limit by which dietary intervention needs to be initiated to elicit a beneficial response on peripheral nerve health.
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Affiliation(s)
- Sunitha Rangaraju
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610-0244, USA
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Abstract
Multisubunit complexes containing molecular chaperones regulate protein production, stability, and degradation in virtually every cell type. We are beginning to recognize how generalized and tissue-specific chaperones regulate specialized aspects of erythropoiesis. For example, chaperones intersect with erythropoietin signaling pathways to protect erythroid precursors against apoptosis. Molecular chaperones also participate in hemoglobin synthesis, both directly and indirectly. Current knowledge in these areas only scratches the surface of what is to be learned. Improved understanding of how molecular chaperones regulate erythropoietic development and hemoglobin homeostasis should identify biochemical pathways amenable to pharmacologic manipulation in a variety of red blood cell disorders including thalassemia and other anemias associated with hemoglobin instability.
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