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Dinamarca MC, Colombo L, Brykczynska U, Grimm A, Fruh I, Hossain I, Gabriel D, Eckert A, Müller M, Pecho-Vrieseling E. Transmission-selective muscle pathology induced by the active propagation of mutant huntingtin across the human neuromuscular synapse. Front Mol Neurosci 2024; 16:1287510. [PMID: 38235149 PMCID: PMC10791992 DOI: 10.3389/fnmol.2023.1287510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/27/2023] [Indexed: 01/19/2024] Open
Abstract
Neuron-to-neuron transmission of aggregation-prone, misfolded proteins may potentially explain the spatiotemporal accumulation of pathological lesions in the brains of patients with neurodegenerative protein-misfolding diseases (PMDs). However, little is known about protein transmission from the central nervous system to the periphery, or how this propagation contributes to PMD pathology. To deepen our understanding of these processes, we established two functional neuromuscular systems derived from human iPSCs. One was suitable for long-term high-throughput live-cell imaging and the other was adapted to a microfluidic system assuring that connectivity between motor neurons and muscle cells was restricted to the neuromuscular junction. We show that the Huntington's disease (HD)-associated mutant HTT exon 1 protein (mHTTEx1) is transmitted from neurons to muscle cells across the human neuromuscular junction. We found that transmission is an active and dynamic process that starts before aggregate formation and is regulated by synaptic activity. We further found that transmitted mHTTEx1 causes HD-relevant pathology at both molecular and functional levels in human muscle cells, even in the presence of the ubiquitous expression of mHTTEx1. In conclusion, we have uncovered a causal link between mHTTEx1 synaptic transmission and HD pathology, highlighting the therapeutic potential of blocking toxic protein transmission in PMDs.
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Affiliation(s)
- Margarita C. Dinamarca
- Neuronal Development and Degeneration Laboratory, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Laura Colombo
- Neuronal Development and Degeneration Laboratory, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Urszula Brykczynska
- Neuronal Development and Degeneration Laboratory, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Amandine Grimm
- Neurobiology Laboratory for Brain Aging and Mental Health, Transfaculty Research Platform, Molecular and Cognitive Neuroscience, University of Basel, Basel, Switzerland
| | - Isabelle Fruh
- Biomedical Research, Novartis Pharma AG, Novartis Campus, Basel, Switzerland
| | - Imtiaz Hossain
- Biomedical Research, Novartis Pharma AG, Novartis Campus, Basel, Switzerland
| | - Daniela Gabriel
- Biomedical Research, Novartis Pharma AG, Novartis Campus, Basel, Switzerland
| | - Anne Eckert
- Neurobiology Laboratory for Brain Aging and Mental Health, Transfaculty Research Platform, Molecular and Cognitive Neuroscience, University of Basel, Basel, Switzerland
| | - Matthias Müller
- Biomedical Research, Novartis Pharma AG, Novartis Campus, Basel, Switzerland
| | - Eline Pecho-Vrieseling
- Neuronal Development and Degeneration Laboratory, Department of Biomedicine, University of Basel, Basel, Switzerland
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2
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Barwell T, Raina S, Page A, MacCharles H, Seroude L. Juvenile and adult expression of polyglutamine expanded huntingtin produce distinct aggregate distributions in Drosophila muscle. Hum Mol Genet 2023; 32:2656-2668. [PMID: 37369041 DOI: 10.1093/hmg/ddad098] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 05/09/2023] [Accepted: 06/02/2023] [Indexed: 06/29/2023] Open
Abstract
While Huntington's disease (HD) is widely recognized as a disease affecting the nervous system, much evidence has accumulated to suggest peripheral or non-neuronal tissues are affected as well. Here, we utilize the UAS/GAL4 system to express a pathogenic HD construct in the muscle of the fly and characterize the effects. We observe detrimental phenotypes such as a reduced lifespan, decreased locomotion and accumulation of protein aggregates. Strikingly, depending on the GAL4 driver used to express the construct, we saw different aggregate distributions and severity of phenotypes. These different aggregate distributions were found to be dependent on the expression level and the timing of expression. Hsp70, a well-documented suppressor of polyglutamine aggregates, was found to strongly reduce the accumulation of aggregates in the eye, but in the muscle, it did not prevent the reduction of the lifespan. Therefore, the molecular mechanisms underlying the detrimental effects of aggregates in the muscle are distinct from the nervous system.
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Affiliation(s)
- Taylor Barwell
- Department of Biology, Queen's University, 116 Barrie St, Kingston, Ontario, K7L 3N6, Canada
| | - Sehaj Raina
- Department of Biology, Queen's University, 116 Barrie St, Kingston, Ontario, K7L 3N6, Canada
| | - Austin Page
- Department of Biology, Queen's University, 116 Barrie St, Kingston, Ontario, K7L 3N6, Canada
| | - Hayley MacCharles
- Department of Biology, Queen's University, 116 Barrie St, Kingston, Ontario, K7L 3N6, Canada
| | - Laurent Seroude
- Department of Biology, Queen's University, 116 Barrie St, Kingston, Ontario, K7L 3N6, Canada
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3
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Pradhan SS, Thota SM, Rajaratnam S, Bhagavatham SKS, Pulukool SK, Rathnakumar S, Phalguna KS, Dandamudi RB, Pargaonkar A, Joseph P, Joshy EV, Sivaramakrishnan V. Integrated multi-omics analysis of Huntington disease identifies pathways that modulate protein aggregation. Dis Model Mech 2022; 15:dmm049492. [PMID: 36052548 PMCID: PMC10655815 DOI: 10.1242/dmm.049492] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 08/15/2022] [Indexed: 11/20/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disease associated with polyglutamine expansion in the protein huntingtin (HTT). Although the length of the polyglutamine repeat correlates with age at disease onset and severity, psychological, cognitive and behavioral complications point to the existence of disease modifiers. Mitochondrial dysfunction and metabolic deregulation are both associated with the HD but, despite multi-omics characterization of patients and model systems, their mechanisms have remained elusive. Systems analysis of multi-omics data and its validation by using a yeast model could help to elucidate pathways that modulate protein aggregation. Metabolomics analysis of HD patients and of a yeast model of HD was, therefore, carried out. Our analysis showed a considerable overlap of deregulated metabolic pathways. Further, the multi-omics analysis showed deregulated pathways common in human, mice and yeast model systems, and those that are unique to them. The deregulated pathways include metabolic pathways of various amino acids, glutathione metabolism, longevity, autophagy and mitophagy. The addition of certain metabolites as well as gene knockouts targeting the deregulated metabolic and autophagy pathways in the yeast model system showed that these pathways do modulate protein aggregation. Taken together, our results showed that the modulation of deregulated pathways influences protein aggregation in HD, and has implications for progression and prognosis. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sai S. Pradhan
- Disease Biology Lab, Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh, India515134
| | - Sai M. Thota
- Disease Biology Lab, Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh, India515134
| | - Saiswaroop Rajaratnam
- Disease Biology Lab, Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh, India515134
| | - Sai K. S. Bhagavatham
- Disease Biology Lab, Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh, India515134
| | - Sujith K. Pulukool
- Disease Biology Lab, Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh, India515134
| | - Sriram Rathnakumar
- Disease Biology Lab, Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh, India515134
| | - Kanikaram S. Phalguna
- Disease Biology Lab, Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh, India515134
| | - Rajesh B. Dandamudi
- Department of Chemistry, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh 515 134, India
| | - Ashish Pargaonkar
- Application Division, Agilent Technologies Ltd., Bengaluru 560048, India
| | - Prasanth Joseph
- Application Division, Agilent Technologies Ltd., Bengaluru 560048, India
| | - E. V. Joshy
- Department of Neurology, Sri Sathya Sai Institute of Higher Medical Sciences, Whitefield, Bengaluru, Karnataka 560066, India
| | - Venketesh Sivaramakrishnan
- Disease Biology Lab, Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Prasanthi Nilayam, Anantapur, Andhra Pradesh, India515134
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4
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Singh A, Agrawal N. Metabolism in Huntington's disease: a major contributor to pathology. Metab Brain Dis 2022; 37:1757-1771. [PMID: 34704220 DOI: 10.1007/s11011-021-00844-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/15/2021] [Indexed: 01/01/2023]
Abstract
Huntington's disease (HD) is a progressively debilitating neurodegenerative disease exhibiting autosomal-dominant inheritance. It is caused by an unstable expansion in the CAG repeat tract of HD gene, which transforms the disease-specific Huntingtin protein (HTT) to a mutant form (mHTT). The profound neuronal death in cortico-striatal circuits led to its identification and characterisation as a neurodegenerative disease. However, equally disturbing are the concomitant whole-body manifestations affecting nearly every organ of the diseased individuals, at varying extents. Altered central and peripheral metabolism of energy, proteins, nucleic acids, lipids and carbohydrates encompass the gross pathology of the disease. Intense fluctuation of body weight, glucose homeostasis and organ-specific subcellular abnormalities are being increasingly recognised in HD. Many of these metabolic abnormalities exist years before the neuropathological manifestations such as chorea, cognitive decline and behavioural abnormalities develop, and prove to be reliable predictors of the disease progression. In this review, we provide a consolidated overview of the central and peripheral metabolic abnormalities associated with HD, as evidenced from clinical and experimental studies. Additionally, we have discussed the potential of metabolic biomolecules to translate into efficient biomarkers for the disease onset as well as progression. Finally, we provide a brief outlook on the efficacy of existing therapies targeting metabolic remediation. While it is clear that components of altered metabolic pathways can mark many aspects of the disease, it is only conceivable that combinatorial therapies aiming for neuronal protection in consort with metabolic upliftment will prove to be more efficient than the existing symptomatic treatment options.
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Affiliation(s)
- Akanksha Singh
- Department of Zoology, University of Delhi, New Delhi, 110007, India
| | - Namita Agrawal
- Department of Zoology, University of Delhi, New Delhi, 110007, India.
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5
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Manzke P, Crippa JADS, Marchioni C, Queiroz MEC, Brito MCM, Pimentel AV, Bosaipo NB, Foss MP, Tumas V. Circulating Endocannabinoids in Huntington's Disease: An Exploratory Cross-Sectional Study. J Huntingtons Dis 2022; 11:91-95. [PMID: 35124656 DOI: 10.3233/jhd-210507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disease characterized by motor, cognitive and behavioral deficits. Some evidence suggests that the endocannabinoid system participates in the pathophysiology of HD. We conducted a cross-sectional study comparing plasma levels of anandamide and 2-arachidonoylglycerol in manifest HD gene-expansion carriers (HDGEC) and healthy controls, finding no difference in endocannabinoid levels between the groups. Correlations between endocannabinoid levels and clinical scales (Mini-Mental State Examination, Hospital Anxiety and Depression Scale, Unified Huntington Disease Rating Scale) were non-significant. We found a significant association between body mass index and anandamide levels in healthy controls but not in HDGEC.
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Affiliation(s)
- Pedro Manzke
- Hospital de Base do Distrito Federal, Brasilia, Brazil.,Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | | | - Camila Marchioni
- School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | | | - Manuelina C M Brito
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Angela V Pimentel
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Nayanne B Bosaipo
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Maria Paula Foss
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Vitor Tumas
- Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
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6
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Khan MS, Shaw RM. Huntington's disease skeletal muscle has altered T-tubules. J Gen Physiol 2021; 153:e202012843. [PMID: 33978682 PMCID: PMC8126974 DOI: 10.1085/jgp.202012843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Romer et al. explored T-tubules in skeletal muscle.
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Affiliation(s)
- Muhammad S. Khan
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT
| | - Robin M. Shaw
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT
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7
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Singh A, Agrawal N. Deciphering the key mechanisms leading to alteration of lipid metabolism in Drosophila model of Huntington's disease. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166127. [PMID: 33722743 DOI: 10.1016/j.bbadis.2021.166127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/27/2021] [Accepted: 03/03/2021] [Indexed: 12/19/2022]
Abstract
Huntington's disease (HD) is an inherited, progressively debilitating disorder marked by prominent degeneration in striatal and cortical brain regions. HD is caused by (CAG)n repeat expansion in huntingtin (HTT) gene that translates into a mutant form of the ubiquitously present Huntingtin (HTT) protein. Extensive metabolic dysfunction coexisting with overt neuropathies has been evidenced in clinical and experimental settings of HD. Body weight loss despite normal to high caloric intake remains a critical determinant of the disease progression and a challenge for therapeutic interventions. In the present study, we intended to monitor the cellular and molecular perturbations in Drosophila, caused by pan-neuronal expression of mHTT (mutant Huntingtin) protein. We found aberrant transcription profile of key lipolytic and lipogenic genes in whole-body of the fly with disease progression. Interestingly, fatbody undergoes extensive alteration of vital cellular processes and eventually surrenders to increased apoptotic cell death in terminal stage of the disease. Extensive mitochondrial dysfunction from early disease stage along with calcium derangement at terminal stage were observed in fatbody, which contribute to its deteriorating integrity. All the mechanisms were monitored progressively, at different disease stages, and many alterations were documented in the early stage itself. Our study hence provides insight into the mechanisms through which neuronal expression of mHTT might be inflicting the profound systemic effects, specifically on lipid metabolism, and may open new therapeutic avenues for alleviation of the multidimensional disease.
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Affiliation(s)
- Akanksha Singh
- Department of Zoology, University of Delhi, Delhi 110007, India
| | - Namita Agrawal
- Department of Zoology, University of Delhi, Delhi 110007, India.
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8
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Romer SH, Metzger S, Peraza K, Wright MC, Jobe DS, Song LS, Rich MM, Foy BD, Talmadge RJ, Voss AA. A mouse model of Huntington's disease shows altered ultrastructure of transverse tubules in skeletal muscle fibers. J Gen Physiol 2021; 153:211860. [PMID: 33683318 PMCID: PMC7931643 DOI: 10.1085/jgp.202012637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 11/05/2020] [Accepted: 01/26/2021] [Indexed: 12/12/2022] Open
Abstract
Huntington’s disease (HD) is a fatal and progressive condition with severe debilitating motor defects and muscle weakness. Although classically recognized as a neurodegenerative disorder, there is increasing evidence of cell autonomous toxicity in skeletal muscle. We recently demonstrated that skeletal muscle fibers from the R6/2 model mouse of HD have a decrease in specific membrane capacitance, suggesting a loss of transverse tubule (t-tubule) membrane in R6/2 muscle. A previous report also indicated that Cav1.1 current was reduced in R6/2 skeletal muscle, suggesting defects in excitation–contraction (EC) coupling. Thus, we hypothesized that a loss and/or disruption of the skeletal muscle t-tubule system contributes to changes in EC coupling in R6/2 skeletal muscle. We used live-cell imaging with multiphoton confocal microscopy and transmission electron microscopy to assess the t-tubule architecture in late-stage R6/2 muscle and found no significant differences in the t-tubule system density, regularity, or integrity. However, electron microscopy images revealed that the cross-sectional area of t-tubules at the triad were 25% smaller in R6/2 compared with age-matched control skeletal muscle. Computer simulation revealed that the resulting decrease in the R6/2 t-tubule luminal conductance contributed to, but did not fully explain, the reduced R6/2 membrane capacitance. Analyses of bridging integrator-1 (Bin1), which plays a primary role in t-tubule formation, revealed decreased Bin1 protein levels and aberrant splicing of Bin1 mRNA in R6/2 muscle. Additionally, the distance between the t-tubule and sarcoplasmic reticulum was wider in R6/2 compared with control muscle, which was associated with a decrease in junctophilin 1 and 2 mRNA levels. Altogether, these findings can help explain dysregulated EC coupling and motor impairment in Huntington’s disease.
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Affiliation(s)
- Shannon H Romer
- Department of Biological Sciences, Wright State University, Dayton, OH.,Odyssey Systems, Environmental Health Effects Laboratory, Navy Medical Research Unit, Dayton, Wright-Patterson Air Force Base, Dayton, OH
| | - Sabrina Metzger
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
| | - Kristiana Peraza
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA
| | - Matthew C Wright
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA
| | - D Scott Jobe
- Department of Biological Sciences, Wright State University, Dayton, OH
| | - Long-Sheng Song
- Division of Cardiovascular Medicine, Department of Internal Medicine, Abboud Cardiovascular Research Center, University of Iowa Carver College of Medicine, Iowa City, IA
| | - Mark M Rich
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
| | - Brent D Foy
- Department of Physics, Wright State University, Dayton, OH
| | - Robert J Talmadge
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA
| | - Andrew A Voss
- Department of Biological Sciences, Wright State University, Dayton, OH
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9
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Ali M, Boosi Narayana Rao K, Majumder P, Sarkar R, Mapa K. Alterations in inter-organelle crosstalk and Ca 2+ signaling through mitochondria during proteotoxic stresses. Mitochondrion 2020; 57:37-46. [PMID: 33340711 DOI: 10.1016/j.mito.2020.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/25/2020] [Accepted: 12/10/2020] [Indexed: 01/06/2023]
Abstract
BACKGROUND Biogenesis and function of mitochondria is profoundly dependent on cytosolic translation of mitochondrial pre-proteins and its subsequent translocation and folding inside the organelle. Continuous exposure of non-native precursor proteins, exposure to damaging by-products of oxidative phosphorylation, load of mis-targeted or misfolded proteins from neighbouring compartments and unremitting demand of communication between mitochondrial and nuclear genomes, continuously pose proteotoxic threats to the organelle. Our knowledge of cellular mechanisms to cope up with such impending threat of proteotoxicity to mitochondria, is currently evolving. In recent years, several unique response and survival pathways have been discovered shedding light on cellular strategies to cope with stressed and dysfunctional mitochondria. As mitochondria compulsorily communicate with nucleus, cytosol and endoplasmic reticulum (ER) for its own biogenesis and function and in turn maintain critical cellular processes for survival, any impairment in communication by stressed or dysfunctional mitochondria may end up with fatal consequences. DISCUSSION AND IMPLICATION In this review, we have discussed about possible sources of mitochondrial proteotoxicity and the recent developments regarding cellular strategies to counter such stress to overcome dysfunctions of the organelle. Mitochondrial communication with neighbouring subcellular compartments like ER and cytosol during proteotoxic stress have been explored. In the context of mitochondrial proteotoxicity, alterations of crucial inter-organelle connections like ER-mitochondria contact sites and its implication on mitochondrial signaling activity like Ca2+ signaling have been dissected. Furthermore, an overview of pathological conditions, mainly neurodegenerative disorders that are known to be associated with mitochondrial proteotoxicity and Ca2+ dysregulation has been presented.
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Affiliation(s)
- Mudassar Ali
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Kannan Boosi Narayana Rao
- Proteomics and Structural Biology Unit, CSIR-Institute of Genomics and Integrative Biology, Mathura Road, New Delhi 110025, India; Academy of Scientific and Innovative Research, CSIR-HRDG, Ghaziabad, Uttar Pradesh 201002, India
| | - Priyanka Majumder
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Rajasri Sarkar
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Koyeli Mapa
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Greater Noida, Gautam Buddha Nagar, Uttar Pradesh 201314, India; Academy of Scientific and Innovative Research, CSIR-HRDG, Ghaziabad, Uttar Pradesh 201002, India.
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10
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Bozzi M, Sciandra F. Molecular Mechanisms Underlying Muscle Wasting in Huntington's Disease. Int J Mol Sci 2020; 21:ijms21218314. [PMID: 33167595 PMCID: PMC7664236 DOI: 10.3390/ijms21218314] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
Huntington’s disease (HD) is an autosomal dominant neurodegenerative disorder caused by pathogenic expansions of the triplet cytosine-adenosine-guanosine (CAG) within the Huntingtin gene. These expansions lead to a prolongation of the poly-glutamine stretch at the N-terminus of Huntingtin causing protein misfolding and aggregation. Huntingtin and its pathological variants are widely expressed, but the central nervous system is mainly affected, as proved by the wide spectrum of neurological symptoms, including behavioral anomalies, cognitive decline and motor disorders. Other hallmarks of HD are loss of body weight and muscle atrophy. This review highlights some key elements that likely provide a major contribution to muscle atrophy, namely, alteration of the transcriptional processes, mitochondrial dysfunction, which is strictly correlated to loss of energy homeostasis, inflammation, apoptosis and defects in the processes responsible for the protein quality control. The improvement of muscular symptoms has proven to slow the disease progression and extend the life span of animal models of HD, underlining the importance of a deep comprehension of the molecular mechanisms driving deterioration of muscular tissue.
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Affiliation(s)
- Manuela Bozzi
- Dipartimento Universitario di Scienze Biotecnologiche di Base, Cliniche Intensivologiche e Perioperatorie, Sezione di Biochimica e Biochimica Clinica, Università Cattolica del Sacro Cuore di Roma, Largo F. Vito 1, 00168 Roma, Italy
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”– SCITEC Sede di Roma, Largo F. Vito 1, 00168 Roma, Italy;
- Correspondence:
| | - Francesca Sciandra
- Istituto di Scienze e Tecnologie Chimiche “Giulio Natta”– SCITEC Sede di Roma, Largo F. Vito 1, 00168 Roma, Italy;
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11
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Neueder A, Orth M. Mitochondrial biology and the identification of biomarkers of Huntington's disease. Neurodegener Dis Manag 2020; 10:243-255. [PMID: 32746707 DOI: 10.2217/nmt-2019-0033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Apart from finding novel compounds for treating Huntington's disease (HD) an important challenge at present consists in finding reliable read-outs or biomarkers that reflect key biological processes involved in HD pathogenesis. The core elements of HD biology, for example, HTT RNA levels or protein species can serve as biomarker, as could measures from biological systems or pathways in which Huntingtin plays an important role. Here we review the evidence for the involvement of mitochondrial biology in HD. The most consistent findings pertain to mitochondrial quality control, for example, fission/fusion. However, a convincing mitochondrial signature with biomarker potential is yet to emerge. This requires more research including in peripheral sources of human material, such as blood, or skeletal muscle.
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Affiliation(s)
| | - Michael Orth
- Department of Neurology, Ulm University, Ulm, Germany.,SwissHuntington's Disease Centre, Neurozentrum Siloah, Worbstr. 312, 3073 Gümligenbei Bern, Switzerland
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12
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Vivekananda U, Turner C. A model to predict ventilator requirement in myotonic dystrophy type 1. Muscle Nerve 2019; 59:683-687. [PMID: 30895625 DOI: 10.1002/mus.26471] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 03/17/2019] [Accepted: 03/19/2019] [Indexed: 11/07/2022]
Abstract
INTRODUCTION Respiratory failure is one of the most common causes of mortality in myotonic dystrophy type 1 (DM1). The variation in the DM1 phenotype causes difficulty in clinically predicting the severity of respiratory involvement, and variables such as daytime somnolence are insensitive for identifying patients who require continuous or bilevel nocturnal positive airway pressure (NPAP). METHODS We retrospectively analyzed a cohort of 126 adult onset patients with DM1 at the point of their first respiratory assessment to identify significant factors in predicting ventilator requirement. RESULTS Triplet repeat years score and Muscle Impairment Rating Scale were significantly linearly related to NPAP and, thus, formed the model. DISCUSSION We devised a simple model to aid clinicians in predicting at first visit those patients with DM1 who are likely to require NPAP. We also describe the causes of failure to tolerate NPAP in DM1. Muscle Nerve 59:683-687, 2019.
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Affiliation(s)
- Umesh Vivekananda
- MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom
| | - Chris Turner
- MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom
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13
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Zadel M, Maver A, Kovanda A, Peterlin B. Transcriptomic Biomarkers for Huntington's Disease: Are Gene Expression Signatures in Whole Blood Reliable Biomarkers? OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2019; 22:283-294. [PMID: 29652574 DOI: 10.1089/omi.2017.0206] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Huntington's disease (HD) is a severe neurodegenerative disorder manifesting as progressive impairment of motor function, cognitive decline, psychiatric symptoms, and immunological and endocrine dysfunction. We explored the consistency of blood transcriptomic biomarkers in HD based on a novel Slovene patient cohort and expert review of previous studies. HumanHT-12 v4 BeadChip microarrays were performed on the whole blood samples of a cohort of 23 HD mutation carriers and 23 controls to identify differentially expressed (DE) transcripts. In addition, we performed an expert review of DE transcripts identified in comparable HD studies from whole blood, to identify any consistent signature of HD. In the Slovene cohort, we identified 740 DE transcripts (p < 0.01 and a false discovery rate (FDR) of <0.1) of which 414 were downregulated and 326 were upregulated. Pathway analyses of DE transcripts showed enrichment for pathways involved in systemic, rather than neural processes in HD. With an expert review of comparable studies, we have further identified 15 DE transcripts shared by 3 studies. We suggest transcriptomic changes in blood reflect systemic changes in HD pathogenesis, rather than being a direct result of the neuropathological processes in the central nervous system during HD progression, and thus, have limited value as disease biomarkers.
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Affiliation(s)
- Maja Zadel
- 1 Community Health Centre Ljubljana, Ljubljana, Slovenia
| | - Aleš Maver
- 2 Clinical Institute of Medical Genetics, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Anja Kovanda
- 2 Clinical Institute of Medical Genetics, University Medical Centre Ljubljana , Ljubljana, Slovenia
| | - Borut Peterlin
- 2 Clinical Institute of Medical Genetics, University Medical Centre Ljubljana , Ljubljana, Slovenia
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Abstract
Polyglutamine (polyQ) diseases are a group of hereditary neurodegenerative disorders caused by expansion of unstable polyQ repeats in their associated disease proteins. To date, the pathogenesis of each disease remains poorly understood, and there are no effective treatments. Growing evidence has indicated that, in addition to neurodegeneration, polyQ-expanded proteins can cause a wide array of abnormalities in peripheral tissues. Indeed, polyQ-expanded proteins are ubiquitously expressed throughout the body and can affect the function of both the central nervous system (CNS) and peripheral tissues. The peripheral effects of polyQ disease proteins include muscle wasting and reduced muscle strength in patients or animal models of spinal and bulbar muscular atrophy (SBMA), Huntington's disease (HD), dentatorubral-pallidoluysian atrophy (DRPLA), and spinocerebellar ataxia type 17 (SCA17). Since skeletal muscle pathology can reflect disease progression and is more accessible for treatment than neurodegeneration in the CNS, understanding how polyQ disease proteins affect skeletal muscle will help elucidate disease mechanisms and the development of new therapeutics. In this review, we focus on important findings in terms of skeletal muscle pathology in polyQ diseases and also discuss the potential mechanisms underlying the major peripheral effects of polyQ disease proteins, as well as their therapeutic implications.
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Affiliation(s)
- Shanshan Huang
- Department of Neurology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Suiqiang Zhu
- Department of Neurology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Xiao-Jiang Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
| | - Shihua Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, USA
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15
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Jędrak P, Mozolewski P, Węgrzyn G, Więckowski MR. Mitochondrial alterations accompanied by oxidative stress conditions in skin fibroblasts of Huntington's disease patients. Metab Brain Dis 2018; 33:2005-2017. [PMID: 30120672 PMCID: PMC6244791 DOI: 10.1007/s11011-018-0308-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/12/2018] [Indexed: 01/08/2023]
Abstract
Huntington disease (HD) is an autosomal dominant neurodegenerative disorder manifesting as progressive impairment of motor function and different neuropsychiatric symptoms caused by an expansion of CAG repeats in huntingtin gene (HTT). Mitochondrial dysfunction and bioenergetic defects can contribute to the course of the disease, however, the molecular mechanism underlying this process is still largely unknown. In this study, we aimed to determine several mitochondrial parameters in HD fibroblasts and assess their relevance to the disease progression as well as to value mitochondrial pathology in peripheral cells as disease potential biomarker. We showed that HD fibroblasts demonstrate significantly lower growth rate compared to control fibroblasts despite the lack of cell cycle perturbations. In order to investigate mitochondrial contribution to cell growth differences between HD and healthy cells, we provided insight into various mitochondrial parameters. Conducted experiments have revealed a significant reduction of the ATP level in HD fibroblasts accompanied by a decrease in mitochondrial metabolic activity in relation to the cells from healthy donors. Importantly, there were no differences in the mitochondrial membrane potential (mtΔΨ) and OXPHOS complexes' levels. Slightly increased level of mitochondrial superoxide (mt. O2•-), but not cytosolic reactive oxygen species (cyt. ROS), has been demonstrated. We have also observed significantly elevated levels of some antioxidant enzymes (SOD2 and GR) which may serve as an indicator of antioxidant defense system in HD patients. Thus, we suggest that mitochondrial alterations in skin fibroblasts of Huntington's disease patients might be helpful in searching for novel disease biomarkers.
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Affiliation(s)
- Paulina Jędrak
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Paweł Mozolewski
- Department of Medical Biology and Genetics, University of Gdańsk, Gdańsk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
| | - Mariusz R Więckowski
- Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093, Warsaw, Poland.
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16
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Zhang X, Wan JQ, Tong XP. Potassium channel dysfunction in neurons and astrocytes in Huntington's disease. CNS Neurosci Ther 2018; 24:311-318. [PMID: 29377621 DOI: 10.1111/cns.12804] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 12/24/2017] [Accepted: 12/25/2017] [Indexed: 01/09/2023] Open
Abstract
Huntington's disease (HD) is a late-onset fatal neurodegenerative disease, characterized by progressive movement disorders, psychiatric symptoms, and cognitive impairment. The cytosine-adenine-guanine (CAG) triplet expansion encoding glutamine present in the protein huntingtin (Htt), produces widespread neuronal and glial pathology. Mutant huntingtin (mHtt) nuclear aggregates are the primary cause of cortical and striatal neuron degeneration, neuronal inflammation, apoptosis and eventual cell loss. The precise mechanisms underlying the pathogenesis of neurodegeneration in HD remain poorly understood and HD patients have no current cure. Potassium channels are widely expressed in most cell types. In neurons, they play a crucial role in setting the resting membrane potential, mediating the rapid repolarization phase of the action potential and controlling sub-threshold oscillations of membrane potentials. In glial cells, their major contributions are maintaining the resting membrane potential and buffering extracellular K+ . Thus, potassium channels have an essential function in both physiological and pathological brain conditions. This review summarizes recent progress on potassium channels involved in the pathology of HD by using different HD mouse models. Exploring the dysfunction of potassium channels in the brain illustrates new approaches for targeting this channel for the treatment of HD.
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Affiliation(s)
- Xiao Zhang
- Discipline of Neuroscience and Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jie-Qing Wan
- Department of Neurological Surgery, Ren Ji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Ping Tong
- Discipline of Neuroscience and Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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17
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Mueller SM, Gehrig SM, Petersen JA, Frese S, Mihaylova V, Ligon-Auer M, Khmara N, Nuoffer JM, Schaller A, Lundby C, Toigo M, Jung HH. Effects of endurance training on skeletal muscle mitochondrial function in Huntington disease patients. Orphanet J Rare Dis 2017; 12:184. [PMID: 29258585 PMCID: PMC5735536 DOI: 10.1186/s13023-017-0740-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/07/2017] [Indexed: 12/12/2022] Open
Abstract
Background Mitochondrial dysfunction may represent a pathogenic factor in Huntington disease (HD). Physical exercise leads to enhanced mitochondrial function in healthy participants. However, data on effects of physical exercise on HD skeletal muscle remains scarce. We aimed at investigating adaptations of the skeletal muscle mitochondria to endurance training in HD patients. Methods Thirteen HD patients and 11 healthy controls completed 26 weeks of endurance training. Before and after the training phase muscle biopsies were obtained from M. vastus lateralis. Mitochondrial respiratory chain complex activities, mitochondrial respiratory capacity, capillarization, and muscle fiber type distribution were determined from muscle samples. Results Citrate synthase activity increased during the training intervention in the whole cohort (P = 0.006). There was no group x time interaction for citrate synthase activity during the training intervention (P = 0.522). Complex III (P = 0.008), Complex V (P = 0.043), and succinate cytochrome c reductase (P = 0.008) activities increased in HD patients and controls by endurance training. An increase in mass-specific mitochondrial respiratory capacity was present in HD patients during the endurance training intervention. Overall capillary-to-fiber ratio increased in HD patients by 8.4% and in healthy controls by 6.4% during the endurance training intervention. Conclusions Skeletal muscle mitochondria of HD patients are equally responsive to an endurance-training stimulus as in healthy controls. Endurance training is a safe and feasible option to enhance indices of energy metabolism in skeletal muscle of HD patients and may represent a potential therapeutic approach to delay the onset and/or progression of muscular dysfunction. Trial registration ClinicalTrials.gov NCT01879267. Registered May 24, 2012.
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Affiliation(s)
- Sandro Manuel Mueller
- Department of Neurology, University Hospital Zurich, , University of Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Saskia Maria Gehrig
- Department of Neurology, University Hospital Zurich, , University of Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Jens A Petersen
- Department of Neurology, University Hospital Zurich, , University of Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Sebastian Frese
- Department of Neurology, University Hospital Zurich, , University of Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | | | - Maria Ligon-Auer
- Department of Neurology, University Hospital Zurich, , University of Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Natalia Khmara
- Department of Neurology, University Hospital Zurich, , University of Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland
| | - Jean-Marc Nuoffer
- Institute of Clinical Chemistry, University Hospital Bern, Bern, Switzerland
| | - André Schaller
- Division of Human Genetics, University Hospital Bern, Bern, Switzerland
| | - Carsten Lundby
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), Zurich, Switzerland
| | - Marco Toigo
- Laboratory for Muscle Plasticity, Balgrist University Hospital, Department of Orthopaedics, University of Zurich, Zurich, Switzerland.,Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland
| | - Hans H Jung
- Department of Neurology, University Hospital Zurich, , University of Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland.
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18
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Bondulich MK, Jolinon N, Osborne GF, Smith EJ, Rattray I, Neueder A, Sathasivam K, Ahmed M, Ali N, Benjamin AC, Chang X, Dick JRT, Ellis M, Franklin SA, Goodwin D, Inuabasi L, Lazell H, Lehar A, Richard-Londt A, Rosinski J, Smith DL, Wood T, Tabrizi SJ, Brandner S, Greensmith L, Howland D, Munoz-Sanjuan I, Lee SJ, Bates GP. Myostatin inhibition prevents skeletal muscle pathophysiology in Huntington's disease mice. Sci Rep 2017; 7:14275. [PMID: 29079832 PMCID: PMC5660167 DOI: 10.1038/s41598-017-14290-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 10/06/2017] [Indexed: 11/09/2022] Open
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disorder of which skeletal muscle atrophy is a common feature, and multiple lines of evidence support a muscle-based pathophysiology in HD mouse models. Inhibition of myostatin signaling increases muscle mass, and therapeutic approaches based on this are in clinical development. We have used a soluble ActRIIB decoy receptor (ACVR2B/Fc) to test the effects of myostatin/activin A inhibition in the R6/2 mouse model of HD. Weekly administration from 5 to 11 weeks of age prevented body weight loss, skeletal muscle atrophy, muscle weakness, contractile abnormalities, the loss of functional motor units in EDL muscles and delayed end-stage disease. Inhibition of myostatin/activin A signaling activated transcriptional profiles to increase muscle mass in wild type and R6/2 mice but did little to modulate the extensive Huntington's disease-associated transcriptional dysregulation, consistent with treatment having little impact on HTT aggregation levels. Modalities that inhibit myostatin signaling are currently in clinical trials for a variety of indications, the outcomes of which will present the opportunity to assess the potential benefits of targeting this pathway in HD patients.
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Affiliation(s)
- Marie K Bondulich
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Nelly Jolinon
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
| | - Georgina F Osborne
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Edward J Smith
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Ivan Rattray
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
| | - Andreas Neueder
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Kirupa Sathasivam
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Mhoriam Ahmed
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Nadira Ali
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Agnesska C Benjamin
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Xiaoli Chang
- Department Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - James R T Dick
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Matthew Ellis
- Division of Neuropathology, UCL Institute of Neurology, London, WC1N 3BG, UK
- Department of Neurodegenerative disease, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Sophie A Franklin
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Daniel Goodwin
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Linda Inuabasi
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
| | - Hayley Lazell
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Adam Lehar
- Department Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Angela Richard-Londt
- Division of Neuropathology, UCL Institute of Neurology, London, WC1N 3BG, UK
- Department of Neurodegenerative disease, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Jim Rosinski
- CHDI Management/CHDI Foundation Inc, New York, NY, 10001, USA
| | - Donna L Smith
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK
| | - Tobias Wood
- Department of Neuroimaging, King's College London, Institute of Psychiatry, London, SE5 8AF, UK
| | - Sarah J Tabrizi
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK
- Department of Neurodegenerative disease, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Sebastian Brandner
- Division of Neuropathology, UCL Institute of Neurology, London, WC1N 3BG, UK
- Department of Neurodegenerative disease, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Linda Greensmith
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK
- MRC Centre for Neuromuscular Diseases, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - David Howland
- CHDI Management/CHDI Foundation Inc, New York, NY, 10001, USA
| | | | - Se-Jin Lee
- Department Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Gillian P Bates
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London Institute of Neurology, London, WC1N 3BG, UK.
- Department Medical and Molecular Genetics, King's College London, London, SE1 9RT, UK.
- Huntington's Disease Centre, UCL Institute of Neurology, London, WC1N 3BG, UK.
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19
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Jędrak P, Krygier M, Tońska K, Drozd M, Kaliszewska M, Bartnik E, Sołtan W, Sitek EJ, Stanisławska-Sachadyn A, Limon J, Sławek J, Węgrzyn G, Barańska S. Mitochondrial DNA levels in Huntington disease leukocytes and dermal fibroblasts. Metab Brain Dis 2017; 32:1237-1247. [PMID: 28508341 PMCID: PMC5504138 DOI: 10.1007/s11011-017-0026-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 05/01/2017] [Indexed: 12/22/2022]
Abstract
Huntington disease (HD) is an inherited neurodegenerative disorder caused by mutations in the huntingtin gene. Involvement of mitochondrial dysfunctions in, and especially influence of the level of mitochondrial DNA (mtDNA) on, development of this disease is unclear. Here, samples of blood from 84 HD patients and 79 controls, and dermal fibroblasts from 10 HD patients and 9 controls were analysed for mtDNA levels. Although the type of mitochondrial haplogroup had no influence on the mtDNA level, and there was no correlation between mtDNA level in leukocytes in HD patients and various parameters of HD severity, some considerable differences between HD patients and controls were identified. The average mtDNA/nDNA relative copy number was significantly higher in leukocytes, but lower in fibroblasts, of symptomatic HD patients relative to the control group. Moreover, HD women displayed higher mtDNA levels in leukocytes than HD men. Because this is the largest population analysed to date, these results might contribute to explanation of discrepancies between previously published studies concerning levels of mtDNA in cells of HD patients. We suggest that the size of the investigated population and type of cells from which DNA is isolated could significantly affect results of mtDNA copy number estimation in HD. Hence, these parameters should be taken into consideration in studies on mtDNA in HD, and perhaps also in other diseases where mitochondrial dysfunction occurs.
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Affiliation(s)
- Paulina Jędrak
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Magdalena Krygier
- Department of Biology and Genetics, Medical University of Gdańsk, Gdańsk, Poland
| | - Katarzyna Tońska
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Małgorzata Drozd
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Magdalena Kaliszewska
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Ewa Bartnik
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
- Polish Academy of Sciences, Institute of Biochemistry and Biophysics, Warsaw, Poland
| | - Witold Sołtan
- Department of Neurology, St. Adalbert Hospital, Copernicus PL Ltd., Gdańsk, Poland
| | - Emilia J Sitek
- Department of Neurology, St. Adalbert Hospital, Copernicus PL Ltd., Gdańsk, Poland
- Department of Neurological and Psychiatric Nursing, Medical University of Gdańsk, Gdańsk, Poland
| | | | - Janusz Limon
- Department of Biology and Genetics, Medical University of Gdańsk, Gdańsk, Poland
| | - Jarosław Sławek
- Department of Neurology, St. Adalbert Hospital, Copernicus PL Ltd., Gdańsk, Poland
- Department of Neurological and Psychiatric Nursing, Medical University of Gdańsk, Gdańsk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland
| | - Sylwia Barańska
- Department of Molecular Biology, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
- Department of Bacterial Molecular Genetics, University of Gdańsk, Wita Stwosza 59, 80-308, Gdańsk, Poland.
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20
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Depressed Synaptic Transmission and Reduced Vesicle Release Sites in Huntington's Disease Neuromuscular Junctions. J Neurosci 2017; 37:8077-8091. [PMID: 28724748 DOI: 10.1523/jneurosci.0313-17.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 07/06/2017] [Accepted: 07/11/2017] [Indexed: 01/25/2023] Open
Abstract
Huntington's disease (HD) is a progressive and fatal degenerative disorder that results in debilitating cognitive and motor dysfunction. Most HD studies have focused on degeneration of the CNS. We previously discovered that skeletal muscle from transgenic R6/2 HD mice is hyperexcitable due to decreased chloride and potassium conductances. The progressive and early onset of these defects suggest a primary myopathy in HD. In this study, we examined the relationship between neuromuscular transmission and skeletal muscle hyperexcitability. We used an ex vivo preparation of the levator auris longus muscle from male and female late-stage R6/2 mice and age-matched wild-type controls. Immunostaining of the synapses and molecular analyses revealed no evidence of denervation. Physiologically, we recorded spontaneous miniature endplate currents (mEPCs) and nerve-evoked EPCs (eEPCs) under voltage-clamp, which, unlike current-clamp records, were independent of the changes in muscle membrane properties. We found a reduction in the number of vesicles released per action potential (quantal content) in R6/2 muscle, which analysis of eEPC variance and morphology indicate is caused by a reduction in the number of vesicle release sites (n) rather than a change in the probability of release (prel). Furthermore, analysis of high-frequency stimulation trains suggests an impairment in vesicle mobilization. The depressed neuromuscular transmission in R6/2 muscle may help compensate for the muscle hyperexcitability and contribute to motor impersistence.SIGNIFICANCE STATEMENT Recent evidence indicates that Huntington's disease (HD) is a multisystem disorder. Our examination of neuromuscular transmission in this study reveals defects in the motor nerve terminal that may compensate for the muscle hyperexcitability in HD. The technique we used eliminates the effects of the altered muscle membrane properties on synaptic currents and thus provides hitherto the most detailed analysis of synaptic transmission in HD. Clinically, the striking depression of neurotransmission we found may help explain the motor impersistence in HD patients. Therapies that target the highly accessible peripheral nerve and muscle system provide a promising new avenue to lessen the debilitating motor symptoms of HD.
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21
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Buck E, Zügel M, Schumann U, Merz T, Gumpp AM, Witting A, Steinacker JM, Landwehrmeyer GB, Weydt P, Calzia E, Lindenberg KS. High-resolution respirometry of fine-needle muscle biopsies in pre-manifest Huntington's disease expansion mutation carriers shows normal mitochondrial respiratory function. PLoS One 2017; 12:e0175248. [PMID: 28406926 PMCID: PMC5390997 DOI: 10.1371/journal.pone.0175248] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/22/2017] [Indexed: 01/31/2023] Open
Abstract
Alterations in mitochondrial respiration are an important hallmark of Huntington's disease (HD), one of the most common monogenetic causes of neurodegeneration. The ubiquitous expression of the disease causing mutant huntingtin gene raises the prospect that mitochondrial respiratory deficits can be detected in skeletal muscle. While this tissue is readily accessible in humans, transgenic animal models offer the opportunity to cross-validate findings and allow for comparisons across organs, including the brain. The integrated respiratory chain function of the human vastus lateralis muscle was measured by high-resolution respirometry (HRR) in freshly taken fine-needle biopsies from seven pre-manifest HD expansion mutation carriers and nine controls. The respiratory parameters were unaffected. For comparison skeletal muscle isolated from HD knock-in mice (HdhQ111) as well as a broader spectrum of tissues including cortex, liver and heart muscle were examined by HRR. Significant changes of mitochondrial respiration in the HdhQ knock-in mouse model were restricted to the liver and the cortex. Mitochondrial mass as quantified by mitochondrial DNA copy number and citrate synthase activity was stable in murine HD-model tissue compared to control. mRNA levels of key enzymes were determined to characterize mitochondrial metabolic pathways in HdhQ mice. We demonstrated the feasibility to perform high-resolution respirometry measurements from small human HD muscle biopsies. Furthermore, we conclude that alterations in respiratory parameters of pre-manifest human muscle biopsies are rather limited and mirrored by a similar absence of marked alterations in HdhQ skeletal muscle. In contrast, the HdhQ111 murine cortex and liver did show respiratory alterations highlighting the tissue specific nature of mutant huntingtin effects on respiration.
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Affiliation(s)
- Eva Buck
- Department of Neurology, Ulm University, Ulm, Germany
| | - Martina Zügel
- Division of Sports- and Rehabilitation Medicine, Ulm University Medical Center, Ulm, Germany
| | - Uwe Schumann
- Division of Sports- and Rehabilitation Medicine, Ulm University Medical Center, Ulm, Germany
| | - Tamara Merz
- Department of Neurology, Ulm University, Ulm, Germany
| | - Anja M. Gumpp
- Department of Neurology, Ulm University, Ulm, Germany
| | - Anke Witting
- Department of Neurology, Ulm University, Ulm, Germany
| | - Jürgen M. Steinacker
- Division of Sports- and Rehabilitation Medicine, Ulm University Medical Center, Ulm, Germany
| | | | - Patrick Weydt
- Department of Neurology, Ulm University, Ulm, Germany
- Department of Neurodegenerative Diseases, Bonn University, Bonn, Germany
| | - Enrico Calzia
- Institute of Anesthesiological Pathophysiology and Process Development, Ulm University, Ulm, Germany
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Hensman Moss DJ, Flower MD, Lo KK, Miller JRC, van Ommen GJB, ’t Hoen PAC, Stone TC, Guinee A, Langbehn DR, Jones L, Plagnol V, van Roon-Mom WMC, Holmans P, Tabrizi SJ. Huntington's disease blood and brain show a common gene expression pattern and share an immune signature with Alzheimer's disease. Sci Rep 2017; 7:44849. [PMID: 28322270 PMCID: PMC5359597 DOI: 10.1038/srep44849] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 02/14/2017] [Indexed: 12/25/2022] Open
Abstract
There is widespread transcriptional dysregulation in Huntington's disease (HD) brain, but analysis is inevitably limited by advanced disease and postmortem changes. However, mutant HTT is ubiquitously expressed and acts systemically, meaning blood, which is readily available and contains cells that are dysfunctional in HD, could act as a surrogate for brain tissue. We conducted an RNA-Seq transcriptomic analysis using whole blood from two HD cohorts, and performed gene set enrichment analysis using public databases and weighted correlation network analysis modules from HD and control brain datasets. We identified dysregulated gene sets in blood that replicated in the independent cohorts, correlated with disease severity, corresponded to the most significantly dysregulated modules in the HD caudate, the most prominently affected brain region, and significantly overlapped with the transcriptional signature of HD myeloid cells. High-throughput sequencing technologies and use of gene sets likely surmounted the limitations of previously inconsistent HD blood expression studies. Our results suggest transcription is disrupted in peripheral cells in HD through mechanisms that parallel those in brain. Immune upregulation in HD overlapped with Alzheimer's disease, suggesting a common pathogenic mechanism involving macrophage phagocytosis and microglial synaptic pruning, and raises the potential for shared therapeutic approaches.
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Affiliation(s)
- Davina J. Hensman Moss
- Department of Neurodegenerative Disease, University College London Institute of Neurology, London, WC1B 5EH, UK
| | - Michael D. Flower
- Department of Neurodegenerative Disease, University College London Institute of Neurology, London, WC1B 5EH, UK
| | - Kitty K. Lo
- University College London Genetics Institute, University College London, London, WC1E 6BT, UK
| | - James R. C. Miller
- Department of Neurodegenerative Disease, University College London Institute of Neurology, London, WC1B 5EH, UK
| | - Gert-Jan B. van Ommen
- Department of Human Genetics, Leiden University Medical Center, Leiden, Postzone S-4-P, The Netherlands
| | - Peter A. C. ’t Hoen
- Department of Human Genetics, Leiden University Medical Center, Leiden, Postzone S-4-P, The Netherlands
| | - Timothy C. Stone
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, CF24 4HQ, UK
| | - Amelia Guinee
- Faculty of Education, University of Cambridge, CB2 8PQ, Cambridge UK
| | - Douglas R. Langbehn
- Departments of Psychiatry and Biostatistics, University of Iowa, IA 52242, USA
| | - Lesley Jones
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, CF24 4HQ, UK
| | - Vincent Plagnol
- University College London Genetics Institute, University College London, London, WC1E 6BT, UK
| | | | - Peter Holmans
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, CF24 4HQ, UK
| | - Sarah J. Tabrizi
- Department of Neurodegenerative Disease, University College London Institute of Neurology, London, WC1B 5EH, UK
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23
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Polyzos AA, McMurray CT. The chicken or the egg: mitochondrial dysfunction as a cause or consequence of toxicity in Huntington's disease. Mech Ageing Dev 2017; 161:181-197. [PMID: 27634555 PMCID: PMC5543717 DOI: 10.1016/j.mad.2016.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 01/30/2023]
Abstract
Mitochondrial dysfunction and ensuing oxidative damage is typically thought to be a primary cause of Huntington's disease, Alzheimer's disease, and Parkinson disease. There is little doubt that mitochondria (MT) become defective as neurons die, yet whether MT defects are the primary cause or a detrimental consequence of toxicity remains unanswered. Oxygen consumption rate (OCR) and glycolysis provide sensitive and informative measures of the functional status MT and the cells metabolic regulation, yet these measures differ depending on the sample source; species, tissue type, age at measurement, and whether MT are measured in purified form or in a cell. The effects of these various parameters are difficult to quantify and not fully understood, but clearly have an impact on interpreting the bioenergetics of MT or their failure in disease states. A major goal of the review is to discuss issues and coalesce detailed information into a reference table to help in assessing mitochondrial dysfunction as a cause or consequence of Huntington's disease.
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Affiliation(s)
- Aris A Polyzos
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA.
| | - Cynthia T McMurray
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA.
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24
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Miranda DR, Wong M, Romer SH, McKee C, Garza-Vasquez G, Medina AC, Bahn V, Steele AD, Talmadge RJ, Voss AA. Progressive Cl- channel defects reveal disrupted skeletal muscle maturation in R6/2 Huntington's mice. J Gen Physiol 2016; 149:55-74. [PMID: 27899419 PMCID: PMC5217084 DOI: 10.1085/jgp.201611603] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 10/03/2016] [Accepted: 11/16/2016] [Indexed: 12/14/2022] Open
Abstract
The R6/2 mouse model of Huntington’s disease exhibits reduced skeletal muscle ClC-1 currents. Miranda et al. investigate early stages of disease in these mice and find an early and progressive disruption of ClC-1 as well as altered muscle maturation based on myosin heavy chain isoform expression. Huntington’s disease (HD) patients suffer from progressive and debilitating motor dysfunction. Previously, we discovered reduced skeletal muscle chloride channel (ClC-1) currents, inwardly rectifying potassium (Kir) channel currents, and membrane capacitance in R6/2 transgenic HD mice. The ClC-1 loss-of-function correlated with increased aberrant mRNA processing and decreased levels of full-length ClC-1 mRNA (Clcn1 gene). Physiologically, the resulting muscle hyperexcitability may help explain involuntary contractions of HD. In this study, the onset and progression of these defects are investigated in R6/2 mice, ranging from 3 wk old (presymptomatic) to 9–13 wk old (late-stage disease), and compared with age-matched wild-type (WT) siblings. The R6/2 ClC-1 current density and level of aberrantly spliced Clcn1 mRNA remain constant with age. In contrast, the ClC-1 current density increases, and the level of aberrantly spliced Clcn1 mRNA decreases with age in WT mice. The R6/2 ClC-1 properties diverge from WT before the onset of motor symptoms, which occurs at 5 wk of age. The relative decrease in R6/2 muscle capacitance also begins in 5-wk-old mice and is independent of fiber atrophy. Kir current density is consistently lower in R6/2 compared with WT muscle. The invariable R6/2 ClC-1 properties suggest a disruption in muscle maturation, which we confirm by measuring elevated levels of neonatal myosin heavy chain (MyHC) in late-stage R6/2 skeletal muscle. Similar changes in ClC-1 and MyHC isoforms in the more slowly developing Q175 HD mice suggest an altered maturational state is relevant to adult-onset HD. Finally, we find nuclear aggregates of muscleblind-like protein 1 without predominant CAG repeat colocalization in R6/2 muscle. This is unlike myotonic dystrophy, another trinucleotide repeat disorder with similar ClC-1 defects, and suggests a novel mechanism of aberrant mRNA splicing in HD. These early and progressive skeletal muscle defects reveal much needed peripheral biomarkers of disease progression and better elucidate the mechanism underlying HD myopathy.
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Affiliation(s)
- Daniel R Miranda
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768.,Department of Biological Sciences, Wright State University, Dayton, OH 45435
| | - Monica Wong
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Shannon H Romer
- Department of Biological Sciences, Wright State University, Dayton, OH 45435
| | - Cynthia McKee
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Gabriela Garza-Vasquez
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Alyssa C Medina
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Volker Bahn
- Department of Biological Sciences, Wright State University, Dayton, OH 45435
| | - Andrew D Steele
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Robert J Talmadge
- Department of Biological Sciences, California State Polytechnic University, Pomona, Pomona, CA 91768
| | - Andrew A Voss
- Department of Biological Sciences, Wright State University, Dayton, OH 45435
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25
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Hering T, Braubach P, Landwehrmeyer GB, Lindenberg KS, Melzer W. Fast-to-Slow Transition of Skeletal Muscle Contractile Function and Corresponding Changes in Myosin Heavy and Light Chain Formation in the R6/2 Mouse Model of Huntington's Disease. PLoS One 2016; 11:e0166106. [PMID: 27820862 PMCID: PMC5098792 DOI: 10.1371/journal.pone.0166106] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 10/24/2016] [Indexed: 11/18/2022] Open
Abstract
Huntington´s disease (HD) is a hereditary neurodegenerative disease resulting from an expanded polyglutamine sequence (poly-Q) in the protein huntingtin (HTT). Various studies report atrophy and metabolic pathology of skeletal muscle in HD and suggest as part of the process a fast-to-slow fiber type transition that may be caused by the pathological changes in central motor control or/and by mutant HTT in the muscle tissue itself. To investigate muscle pathology in HD, we used R6/2 mice, a common animal model for a rapidly progressing variant of the disease expressing exon 1 of the mutant human gene. We investigated alterations in the extensor digitorum longus (EDL), a typical fast-twitch muscle, and the soleus (SOL), a slow-twitch muscle. We focussed on mechanographic measurements of excised muscles using single and repetitive electrical stimulation and on the expression of the various myosin isoforms (heavy and light chains) using dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole muscle and single fiber preparations. In EDL of R6/2, the functional tests showed a left shift of the force-frequency relation and decrease in specific force. Moreover, the estimated relative contribution of the fastest myosin isoform MyHC IIb decreased, whereas the contribution of the slower MyHC IIx isoform increased. An additional change occurred in the alkali MyLC forms showing a decrease in 3f and an increase in 1f level. In SOL, a shift from fast MyHC IIa to the slow isoform I was detectable in male R6/2 mice only, and there was no evidence of isoform interconversion in the MyLC pattern. These alterations point to a partial remodeling of the contractile apparatus of R6/2 mice towards a slower contractile phenotype, predominantly in fast glycolytic fibers.
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Affiliation(s)
- Tanja Hering
- Institute of Applied Physiology, Ulm University, Ulm, Germany
- Department of Neurology, Ulm University, Ulm, Germany
| | - Peter Braubach
- Institute of Applied Physiology, Ulm University, Ulm, Germany
- Institute of Pathology, Hannover Medical School, Hannover, Germany
| | | | | | - Werner Melzer
- Institute of Applied Physiology, Ulm University, Ulm, Germany
- * E-mail:
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26
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Kobal J, Cankar K, Pretnar J, Zaletel M, Kobal L, Teran N, Melik Z. Functional impairment of precerebral arteries in Huntington disease. J Neurol Sci 2016; 372:363-368. [PMID: 27817854 DOI: 10.1016/j.jns.2016.10.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 10/11/2016] [Accepted: 10/21/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Cardiovascular pathology of Huntington disease (HD) appears to be complex; while microvascular dysfunction seems to appear early, deaths from cardiomyopathy and stroke might occur in the late phase of HD. METHODS Our study evaluated global risk factors for coronary heart disease (CHD), structure and function of precerebral arteries in 41 HD subjects and 41 matched controls. HD subjects were divided into groups by the United Huntington disease rating scale (presymptomatic-PHD, early-EHD, midstage-MHD and late-LHD). CHD risk factors assessment and Doppler examination of precerebral arteries were performed, including measurements of the carotid artery intima-media thickness (IMT), and parameters indicating local carotid artery distensibility (stiffness index β, pulse wave velocity, pressure strain elasticity module and carotid artery compliance). RESULTS In the HD and controls we identified a comparable number of non-obstructive plaques (<50% lumen narrowing). No obstructive plaques (>50% lumen narrowing) were found. There was significantly increased IMT in MHD. In PHD and EHD the parameters of arterial stiffness were significantly higher and the carotid artery compliance was significantly lower. CONCLUSIONS Our results reveal functional vascular pathology in PHD, EHD, and MHD. Precerebral arteries dysfunction in HD therefore appears to be mostly functional and in agreement with recently described autonomic nervous system changes in HD.
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Affiliation(s)
- Jan Kobal
- University Medical Centre Ljubljana, Division of Neurology, Ljubljana, Slovenia.
| | - Ksenija Cankar
- University of Ljubljana, Faculty of Medicine, Institute of Physiology, Ljubljana, Slovenia
| | - Janja Pretnar
- University Medical Centre Ljubljana, Division of Neurology, Ljubljana, Slovenia; University of Ljubljana, Faculty of Medicine, Department of Neurology, Ljubljana, Slovenia
| | - Marjan Zaletel
- University Medical Centre Ljubljana, Division of Neurology, Ljubljana, Slovenia
| | - Lucijan Kobal
- University of Ljubljana, Faculty of Medicine, Department of Neurology, Ljubljana, Slovenia
| | - Natasa Teran
- University Medical Centre Ljubljana, Division of Gynaecology and Obstetrics, Ljubljana, Slovenia
| | - Ziva Melik
- University of Ljubljana, Faculty of Medicine, Institute of Physiology, Ljubljana, Slovenia
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27
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Abstract
Redox homeostasis is crucial for proper cellular functions, including receptor tyrosine kinase signaling, protein folding, and xenobiotic detoxification. Under basal conditions, there is a balance between oxidants and antioxidants. This balance facilitates the ability of oxidants, such as reactive oxygen species, to play critical regulatory functions through a direct modification of a small number of amino acids (e.g. cysteine) on signaling proteins. These signaling functions leverage tight spatial, amplitude, and temporal control of oxidant concentrations. However, when oxidants overwhelm the antioxidant capacity, they lead to a harmful condition of oxidative stress. Oxidative stress has long been held to be one of the key players in disease progression for Huntington's disease (HD). In this review, we will critically review this evidence, drawing some intermediate conclusions, and ultimately provide a framework for thinking about the role of oxidative stress in the pathophysiology of HD.
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Affiliation(s)
- Amit Kumar
- Burke Medical Research Institute, White Plains, NY, USA
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA
- Department of Neurology, Weill Medical College of Cornell University, New York, NY, USA
| | - Rajiv R. Ratan
- Burke Medical Research Institute, White Plains, NY, USA
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA
- Department of Neurology, Weill Medical College of Cornell University, New York, NY, USA
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28
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Altered lipid metabolism in Drosophila model of Huntington's disease. Sci Rep 2016; 6:31411. [PMID: 27506601 PMCID: PMC4979013 DOI: 10.1038/srep31411] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 07/21/2016] [Indexed: 11/20/2022] Open
Abstract
Huntington’s disease (HD) is late-onset, progressive neurodegenerative disorder caused by expansion of polyglutamine (polyQ) repeat within Huntingtin (Htt) protein. In HD patients, energy-related manifestations such as modulation of weight during entire course of disease with energy deficit at terminal stage have been reported, however, underlying reason remains elusive till date. Lipids, carbohydrate and protein constitute a predominant fraction of body’s energy reservoir and perturbation in their homeostasis may influence weight. To discern role of these energy molecules in weight alteration, we quantified them in an in vivo transgenic Drosophila model of HD. We document that diseased flies exhibit change in weight due to an altered lipid metabolism, as evident from considerably high lipid levels at the time of disease onset followed by a pathologic decline at end-stage. An alteration in intracellular lipid droplet size suggested altered cellular lipid turnover. Furthermore, diseased flies displayed substantial changes in carbohydrate and protein content. Interestingly, alteration in weight and lipid levels are independent of the feeding pattern in diseased condition and exhibit weak correlation with insulin-like peptide or adipokinetic hormone producing cells. We propose that therapeutic intervention aimed at restoring lipid levels and associated metabolic pathways may improve longevity and quality of patient’s life.
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29
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Brustovetsky N. Mutant Huntingtin and Elusive Defects in Oxidative Metabolism and Mitochondrial Calcium Handling. Mol Neurobiol 2016; 53:2944-2953. [PMID: 25941077 PMCID: PMC4635103 DOI: 10.1007/s12035-015-9188-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 04/22/2015] [Indexed: 01/13/2023]
Abstract
Elongation of a polyglutamine (polyQ) stretch in huntingtin protein (Htt) is linked to Huntington's disease (HD) pathogenesis. The mutation in Htt correlates with neuronal dysfunction in the striatum and cerebral cortex and eventually leads to neuronal cell death. The exact mechanisms of the injurious effect of mutant Htt (mHtt) on neurons are not completely understood but might include aberrant gene transcription, defective autophagy, abnormal mitochondrial biogenesis, anomalous mitochondrial dynamics, and trafficking. In addition, deficiency in oxidative metabolism and defects in mitochondrial Ca(2+) handling are considered essential contributing factors to neuronal dysfunction in HD and, consequently, in HD pathogenesis. Since the discovery of the mutation in Htt, the questions whether mHtt affects oxidative metabolism and mitochondrial Ca(2+) handling and, if it does, what mechanisms could be involved were in focus of numerous investigations. However, despite significant research efforts, the detrimental effect of mHtt and the mechanisms by which mHtt might impair oxidative metabolism and mitochondrial Ca(2+) handling remain elusive. In this paper, I will briefly review studies aimed at clarifying the consequences of mHtt interaction with mitochondria and discuss experimental results supporting or arguing against the mHtt effects on oxidative metabolism and mitochondrial Ca(2+) handling.
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Affiliation(s)
- Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, 635 Barnhill Dr., Medical Science Bldg 547, Indianapolis, IN, 46202, USA.
- Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
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30
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Chandra A, Sharma A, Calingasan NY, White JM, Shurubor Y, Yang XW, Beal MF, Johri A. Enhanced mitochondrial biogenesis ameliorates disease phenotype in a full-length mouse model of Huntington's disease. Hum Mol Genet 2016; 25:2269-2282. [PMID: 27008868 DOI: 10.1093/hmg/ddw095] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/17/2016] [Indexed: 12/28/2022] Open
Abstract
Huntington's disease (HD) is a devastating illness and at present there is no disease modifying therapy or cure for it; and management of the disease is limited to a few treatment options for amelioration of symptoms. Recently, we showed that the administration of bezafibrate, a pan-PPAR agonist, increases the expression of PGC-1α and mitochondrial biogenesis, and improves phenotype and survival in R6/2 transgenic mouse model of HD. Since the R6/2 mice represent a 'truncated' huntingtin (Htt) mouse model of HD, we tested the efficacy of bezafibrate in a 'full-length' Htt mouse model, the BACHD mice. Bezafibrate treatment restored the impaired PPARγ, PPARδ, PGC-1α signaling pathway, enhanced mitochondrial biogenesis and improved antioxidant defense in the striatum of BACHD mice. Untreated BACHD mice show robust and progressive motor deficits, as well as late-onset and selective neuropathology in the striatum, which was markedly ameliorated in the BACHD mice treated with bezafibrate. Our data demonstrate the efficacy of bezafibrate in ameliorating both neuropathological features and disease phenotype in BACHD mice, and taken together with our previous studies with the R6/2 mice, highlight the strong therapeutic potential of bezafibrate for treatment of HD.
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Affiliation(s)
- Abhishek Chandra
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Abhijeet Sharma
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Noel Y Calingasan
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Joshua M White
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Yevgeniya Shurubor
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - X William Yang
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior; Department of Psychiatry and Biobehavioral Sciences; and Brain Research Institute, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - M Flint Beal
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
| | - Ashu Johri
- Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10065, USA
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31
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Filosto M, Lanzi G, Nesti C, Vielmi V, Marchina E, Galvagni A, Giliani S, Santorelli FM, Padovani A. A novel mitochondrial tRNA(Ala) gene variant causes chronic progressive external ophthalmoplegia in a patient with Huntington disease. Mol Genet Metab Rep 2016; 6:70-3. [PMID: 27014581 PMCID: PMC4789388 DOI: 10.1016/j.ymgmr.2016.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2016] [Accepted: 02/07/2016] [Indexed: 12/14/2022] Open
Abstract
Chronic progressive external ophthalmoplegia is a mitochondrial disorder usually caused by single or multiple mitochondrial DNA (mtDNA) deletions and, more rarely, by maternally inherited mtDNA point mutations, most frequently in tRNA genes (MTT). We report on a patient presenting with a progressive eyelid ptosis with bilateral ophthalmoparesis, dysphagia, dysphonia and mild proximal limb weakness associate with a mild movement disorder characterized by abnormal involuntary movements involving head and limbs, imbalance and gait instability. Muscle biopsy demonstrated the presence of ragged red fibers and several cytochrome-C-oxidase negative fibers. Molecular analysis showed the novel m.5613T > C heteroplasmic mutation in the mitochondrial tRNA(Ala) gene (MTTA) which disrupts a conserved site and fulfills the accepted criteria of pathogenicity. Moreover, a 38 CAG trinucleotide repeat expansion was found on the huntingtin gene, thus configuring a singular CPEO/"reduced penetrance" Huntington disease "double trouble". With this novel MTTA point mutation, we extend the spectrum of provisional pathogenic changes in this gene, which is a very rare site of pathogenic mutation, and confirm that clinical expression of these mutations is hardly ever heterogeneous, including myopathy and CPEO. Mitochondrial involvement is an emerging key determinant in the pathogenesis of Huntington disease and it is well known that mutant huntingtin influences the mitochondrial respiratory complexes II and III. A synergist effect of the HTT and MTTA mutations on respiratory chain function may be hypothesized in our patient and should be regarded as a spur for further studies on the mtDNA/HTT reciprocal interactions.
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Affiliation(s)
- Massimiliano Filosto
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital “Spedali Civili”, Brescia, Italy
| | - Gaetana Lanzi
- Institute of Molecular Medicine “A. Nocivelli”, University Hospital “Spedali Civili”, Brescia, Italy
| | - Claudia Nesti
- Unit of Molecular Medicine, IRCCS Stella Maris, Pisa, Italy
| | - Valentina Vielmi
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital “Spedali Civili”, Brescia, Italy
| | - Eleonora Marchina
- Division of Biology and Genetics, Department of Biomedical Sciences and Biotechnology, University of Brescia, Italy
| | - Anna Galvagni
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital “Spedali Civili”, Brescia, Italy
| | - Silvia Giliani
- Institute of Molecular Medicine “A. Nocivelli”, University Hospital “Spedali Civili”, Brescia, Italy
| | | | - Alessandro Padovani
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital “Spedali Civili”, Brescia, Italy
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32
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Mejia EM, Chau S, Sparagna GC, Sipione S, Hatch GM. Reduced Mitochondrial Function in Human Huntington Disease Lymphoblasts is Not Due to Alterations in Cardiolipin Metabolism or Mitochondrial Supercomplex Assembly. Lipids 2016; 51:561-9. [PMID: 26846325 DOI: 10.1007/s11745-015-4110-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 12/01/2015] [Indexed: 10/22/2022]
Abstract
Huntington's Disease (HD) is an autosomal dominant disease that occurs as a result of expansion of the trinucleotide repeat CAG (glutamine) on the HTT gene. HD patients exhibit various forms of mitochondrial dysfunction within neurons and peripheral tissues. Cardiolipin (Ptd2Gro) is a polyglycerophospholipid found exclusively in mitochondria and is important for maintaining mitochondrial function. We examined if altered Ptd2Gro metabolism was involved in the mitochondrial dysfunction associated with HD. Mitochondrial basal respiration, spare respiratory capacity, ATP coupling efficiency and rate of glycolysis were markedly diminished in Epstein-Barr virus transformed HD lymphoblasts compared to controls (CTRL). Mitochondrial supercomplex formation and Complex I activity within these supercomplexes did not vary between HD patients with different length of CAG repeats and appeared unaltered compared to CTRL. In contrast, in vitro Complex I enzyme activity in mitochondrial enriched samples was reduced in HD lymphoblasts compared to CTRL. The total cellular pool size of Ptd2Gro and its synthesis/remodeling from [(3)H]acetate/[(14)C]oleate were unaltered in HD lymphoblasts compared to CTRL. In addition, the molecular species of Ptd2Gro were essentially unaltered in HD lymphoblasts compared to CTRL. We conclude that compared to CTRL lymphoblasts, HD lymphoblasts display impaired mitochondrial basal respiration, spare respiratory capacity, ATP coupling efficiency and rate of glycolysis with any pathological CAG repeat length, but this is not due to alterations in Ptd2Gro metabolism. We suggest that HD patient lymphoblasts may be a useful model to study defective energy metabolism that does not involve alterations in Ptd2Gro metabolism.
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Affiliation(s)
- Edgard M Mejia
- Department of Pharmacology and Therapeutics, Faculty of Health Sciences, University of Manitoba, 501C-715 McDermot Avenue, Winnipeg, MB, R3E 3P4, Canada
| | - Sarah Chau
- Department of Medicine, Division of Cardiology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Genevieve C Sparagna
- Department of Medicine, Division of Cardiology, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Simonetta Sipione
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G2S2, Canada
| | - Grant M Hatch
- Department of Pharmacology and Therapeutics, Faculty of Health Sciences, University of Manitoba, 501C-715 McDermot Avenue, Winnipeg, MB, R3E 3P4, Canada. .,Department of Biochemistry and Medical Genetics, Center for Research and Treatment of Atherosclerosis, University of Manitoba, DREAM Children's Hospital Research Institute of Manitoba, Winnipeg, MB, R3E 0T6, Canada.
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33
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de Aragão BC, Rodrigues HA, Valadão PAC, Camargo W, Naves LA, Ribeiro FM, Guatimosim C. Changes in structure and function of diaphragm neuromuscular junctions from BACHD mouse model for Huntington's disease. Neurochem Int 2016; 93:64-72. [DOI: 10.1016/j.neuint.2015.12.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/17/2015] [Accepted: 12/28/2015] [Indexed: 10/22/2022]
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34
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Treating the whole body in Huntington's disease. Lancet Neurol 2016; 14:1135-42. [PMID: 26466780 DOI: 10.1016/s1474-4422(15)00177-5] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 06/15/2015] [Accepted: 07/03/2015] [Indexed: 12/13/2022]
Abstract
Huntington's disease is a genetic neurodegenerative disorder with symptoms that are linked to the progressive dysfunction and neuronal death in corticostriatal circuits. The causative gene (mutated HTT) is widely expressed outside the CNS and several peripheral signs of disease, including weight loss and increased proinflammatory signalling, are often seen; however, their importance in the pathophysiology of Huntington's disease is not clear. Studies in animals have shown that features of the disease involving the CNS, including synapse loss and behavioural alterations, are susceptible to modulation by treatments that target tissues and organs outside the CNS. Links between peripheral biology and neurodegeneration have also been shown in other chronic neurodegenerative diseases, suggesting that modulation of these peripheral targets can offer new approaches to therapeutic development. Treatments targeted to tissues and organs outside the CNS might therefore substantially improve the quality of life of patients with Huntington's disease, even in the absence of disease-modifying effects.
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Braubach P, Orynbayev M, Andronache Z, Hering T, Landwehrmeyer GB, Lindenberg KS, Melzer W. Altered Ca(2+) signaling in skeletal muscle fibers of the R6/2 mouse, a model of Huntington's disease. ACTA ACUST UNITED AC 2015; 144:393-413. [PMID: 25348412 PMCID: PMC4210430 DOI: 10.1085/jgp.201411255] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Huntington's disease (HD) is caused by an expanded CAG trinucleotide repeat within the gene encoding the protein huntingtin. The resulting elongated glutamine (poly-Q) sequence of mutant huntingtin (mhtt) affects both central neurons and skeletal muscle. Recent reports suggest that ryanodine receptor-based Ca(2+) signaling, which is crucial for skeletal muscle excitation-contraction coupling (ECC), is changed by mhtt in HD neurons. Consequently, we searched for alterations of ECC in muscle fibers of the R6/2 mouse, a mouse model of HD. We performed fluorometric recordings of action potentials (APs) and cellular Ca(2+) transients on intact isolated toe muscle fibers (musculi interossei), and measured L-type Ca(2+) inward currents on internally dialyzed fibers under voltage-clamp conditions. Both APs and AP-triggered Ca(2+) transients showed slower kinetics in R6/2 fibers than in fibers from wild-type mice. Ca(2+) removal from the myoplasm and Ca(2+) release flux from the sarcoplasmic reticulum were characterized using a Ca(2+) binding and transport model, which indicated a significant reduction in slow Ca(2+) removal activity and Ca(2+) release flux both after APs and under voltage-clamp conditions. In addition, the voltage-clamp experiments showed a highly significant decrease in L-type Ca(2+) channel conductance. These results indicate profound changes of Ca(2+) turnover in skeletal muscle of R6/2 mice and suggest that these changes may be associated with muscle pathology in HD.
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Affiliation(s)
- Peter Braubach
- Institute of Applied Physiology and Department of Neurology, Ulm University, D-89081 Ulm, Germany
| | - Murat Orynbayev
- Institute of Applied Physiology and Department of Neurology, Ulm University, D-89081 Ulm, Germany
| | - Zoita Andronache
- Institute of Applied Physiology and Department of Neurology, Ulm University, D-89081 Ulm, Germany
| | - Tanja Hering
- Institute of Applied Physiology and Department of Neurology, Ulm University, D-89081 Ulm, Germany Institute of Applied Physiology and Department of Neurology, Ulm University, D-89081 Ulm, Germany
| | | | - Katrin S Lindenberg
- Institute of Applied Physiology and Department of Neurology, Ulm University, D-89081 Ulm, Germany
| | - Werner Melzer
- Institute of Applied Physiology and Department of Neurology, Ulm University, D-89081 Ulm, Germany
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Hamilton J, Pellman JJ, Brustovetsky T, Harris RA, Brustovetsky N. Oxidative metabolism in YAC128 mouse model of Huntington's disease. Hum Mol Genet 2015; 24:4862-78. [PMID: 26041817 DOI: 10.1093/hmg/ddv209] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 06/01/2015] [Indexed: 12/15/2022] Open
Abstract
Alterations in oxidative metabolism are considered to be one of the major contributors to Huntington's disease (HD) pathogenesis. However, existing data about oxidative metabolism in HD are contradictory. Here, we investigated the effect of mutant huntingtin (mHtt) on oxidative metabolism in YAC128 mice. Both mHtt and wild-type huntingtin (Htt) were associated with mitochondria and the amount of bound Htt was four-times higher than the amount of bound mHtt. Percoll gradient-purified brain synaptic and non-synaptic mitochondria as well as unpurified brain, liver and heart mitochondria, isolated from 2- and 10-month-old YAC128 mice and age-matched WT littermates had similar respiratory rates. There was no difference in mitochondrial membrane potential or ADP and ATP levels. Expression of selected nuclear-encoded mitochondrial proteins in 2- and 10-month-old YAC128 and WT mice was similar. Cultured striatal and cortical neurons from YAC128 and WT mice had similar respiratory and glycolytic activities as measured with Seahorse XF24 analyzer in medium containing 10 mm glucose and 15 mm pyruvate. In the medium with 2.5 mm glucose, YAC128 striatal neurons had similar respiration, but slightly lower glycolytic activity. Striatal neurons had lower maximal respiration compared with cortical neurons. In vivo experiments with YAC128 and WT mice showed similar O2 consumption, CO2 release, physical activity, food consumption and fasted blood glucose. However, YAC128 mice were heavier and had more body fat compared with WT mice. Overall, our data argue against respiratory deficiency in YAC128 mice and, consequently, suggest that mitochondrial respiratory dysfunction is not essential for HD pathogenesis.
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Affiliation(s)
| | | | | | - Robert A Harris
- Department of Biochemistry and Molecular Biology and Richard L. Roudebush VA Medical Center, Indianapolis, IN, USA
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Department of Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, IN 46202, USA and
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Russell AP, Foletta VC, Snow RJ, Wadley GD. Skeletal muscle mitochondria: a major player in exercise, health and disease. Biochim Biophys Acta Gen Subj 2013; 1840:1276-84. [PMID: 24291686 DOI: 10.1016/j.bbagen.2013.11.016] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 11/01/2013] [Accepted: 11/16/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND Maintaining skeletal muscle mitochondrial content and function is important for sustained health throughout the lifespan. Exercise stimulates important key stress signals that control skeletal mitochondrial biogenesis and function. Perturbations in mitochondrial content and function can directly or indirectly impact skeletal muscle function and consequently whole-body health and wellbeing. SCOPE OF REVIEW This review will describe the exercise-stimulated stress signals and molecular mechanisms positively regulating mitochondrial biogenesis and function. It will then discuss the major myopathies, neuromuscular diseases and conditions such as diabetes and ageing that have dysregulated mitochondrial function. Finally, the impact of exercise and potential pharmacological approaches to improve mitochondrial function in diseased populations will be discussed. MAJOR CONCLUSIONS Exercise activates key stress signals that positively impact major transcriptional pathways that transcribe genes involved in skeletal muscle mitochondrial biogenesis, fusion and metabolism. The positive impact of exercise is not limited to younger healthy adults but also benefits skeletal muscle from diseased populations and the elderly. Impaired mitochondrial function can directly influence skeletal muscle atrophy and contribute to the risk or severity of disease conditions. Pharmacological manipulation of exercise-induced pathways that increase skeletal muscle mitochondrial biogenesis and function in critically ill patients, where exercise may not be possible, may assist in the treatment of chronic disease. GENERAL SIGNIFICANCE This review highlights our understanding of how exercise positively impacts skeletal muscle mitochondrial biogenesis and function. Exercise not only improves skeletal muscle mitochondrial health but also enables us to identify molecular mechanisms that may be attractive targets for therapeutic manipulation. This article is part of a Special Issue entitled Frontiers of mitochondrial research.
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Affiliation(s)
- Aaron P Russell
- Centre for Physical Activity and Nutrition (C-PAN) Research, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Hwy, 3125 Burwood, Australia.
| | - Victoria C Foletta
- Centre for Physical Activity and Nutrition (C-PAN) Research, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Hwy, 3125 Burwood, Australia
| | - Rod J Snow
- Centre for Physical Activity and Nutrition (C-PAN) Research, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Hwy, 3125 Burwood, Australia
| | - Glenn D Wadley
- Centre for Physical Activity and Nutrition (C-PAN) Research, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Hwy, 3125 Burwood, Australia
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Johri A, Chandra A, Flint Beal M. PGC-1α, mitochondrial dysfunction, and Huntington's disease. Free Radic Biol Med 2013; 62:37-46. [PMID: 23602910 PMCID: PMC3722269 DOI: 10.1016/j.freeradbiomed.2013.04.016] [Citation(s) in RCA: 156] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 04/06/2013] [Accepted: 04/12/2013] [Indexed: 12/15/2022]
Abstract
The constant high energy demand of neurons makes them rely heavily on their mitochondria. Dysfunction of mitochondrial energy metabolism leads to reduced ATP production, impaired calcium buffering, and generation of reactive oxygen species. There is strong evidence that mitochondrial dysfunction results in neurodegeneration and may contribute to the pathogenesis of Huntington's disease (HD). Studies over the past few years have implicated an impaired function of peroxisome proliferator-activated receptor (PPAR)-γ coactivator-1α (PGC-1α), a transcriptional master coregulator of mitochondrial biogenesis, metabolism, and antioxidant defenses, in causing mitochondrial dysfunction in HD. Here we have attempted to discuss in a nutshell, the key findings on the role of PGC-1α in mitochondrial dysfunction in HD and its potential as a therapeutic target to cure HD.
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Affiliation(s)
- Ashu Johri
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, NY 10065, USA.
| | - Abhishek Chandra
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, NY 10065, USA
| | - M Flint Beal
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, NY 10065, USA
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Damiano M, Diguet E, Malgorn C, D'Aurelio M, Galvan L, Petit F, Benhaim L, Guillermier M, Houitte D, Dufour N, Hantraye P, Canals JM, Alberch J, Delzescaux T, Déglon N, Beal MF, Brouillet E. A role of mitochondrial complex II defects in genetic models of Huntington's disease expressing N-terminal fragments of mutant huntingtin. Hum Mol Genet 2013; 22:3869-82. [PMID: 23720495 PMCID: PMC3766181 DOI: 10.1093/hmg/ddt242] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Huntington's disease (HD) is a neurodegenerative disorder caused by an abnormal expansion of a CAG repeat encoding a polyglutamine tract in the huntingtin (Htt) protein. The mutation leads to neuronal death through mechanisms which are still unknown. One hypothesis is that mitochondrial defects may play a key role. In support of this, the activity of mitochondrial complex II (C-II) is preferentially reduced in the striatum of HD patients. Here, we studied C-II expression in different genetic models of HD expressing N-terminal fragments of mutant Htt (mHtt). Western blot analysis showed that the expression of the 30 kDa Iron–Sulfur (Ip) subunit of C-II was significantly reduced in the striatum of the R6/1 transgenic mice, while the levels of the FAD containing catalytic 70 kDa subunit (Fp) were not significantly changed. Blue native gel analysis showed that the assembly of C-II in mitochondria was altered early in N171-82Q transgenic mice. Early loco-regional reduction in C-II activity and Ip protein expression was also demonstrated in a rat model of HD using intrastriatal injection of lentiviral vectors encoding mHtt. Infection of the rat striatum with a lentiviral vector coding the C-II Ip or Fp subunits induced a significant overexpression of these proteins that led to significant neuroprotection of striatal neurons against mHtt neurotoxicity. These results obtained in vivo support the hypothesis that structural and functional alterations of C-II induced by mHtt may play a critical role in the degeneration of striatal neurons in HD and that mitochondrial-targeted therapies may be useful in its treatment.
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Affiliation(s)
- Maria Damiano
- The first two authors contributed equally to the present study
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Silva AC, Almeida S, Laço M, Duarte AI, Domingues J, Oliveira CR, Januário C, Rego AC. Mitochondrial respiratory chain complex activity and bioenergetic alterations in human platelets derived from pre-symptomatic and symptomatic Huntington's disease carriers. Mitochondrion 2013; 13:801-9. [PMID: 23707479 DOI: 10.1016/j.mito.2013.05.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 04/17/2013] [Accepted: 05/07/2013] [Indexed: 01/14/2023]
Abstract
Mitochondrial dysfunction has been implicated in Huntington's disease (HD) pathogenesis. We analyzed the activity of mitochondrial complexes (Cx) I-IV, protein levels of selected Cx subunits and adenine nucleotides in platelet mitochondria from pre-symptomatic versus symptomatic HD human carriers and age-matched control individuals. Mitochondrial platelets exhibited reduced activity of citrate synthase in pre-symptomatic and Cx-I in pre-symptomatic and symptomatic HD carriers. Positive correlation between Cx activity and protein subunits was observed for Cx-I in symptomatic HD patient's mitochondria. Moreover, AMP increased in mitochondria from pre-symptomatic HD carriers. Results highlight mitochondrial changes occurring before the onset of HD clinical symptoms.
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Affiliation(s)
- Ana C Silva
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Portugal
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41
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Huntington disease skeletal muscle is hyperexcitable owing to chloride and potassium channel dysfunction. Proc Natl Acad Sci U S A 2013; 110:9160-5. [PMID: 23671115 DOI: 10.1073/pnas.1220068110] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Huntington disease is a progressive and fatal genetic disorder with debilitating motor and cognitive defects. Chorea, rigidity, dystonia, and muscle weakness are characteristic motor defects of the disease that are commonly attributed to central neurodegeneration. However, no previous study has examined the membrane properties that control contraction in Huntington disease muscle. We show primary defects in ex vivo adult skeletal muscle from the R6/2 transgenic mouse model of Huntington disease. Action potentials in diseased fibers are more easily triggered and prolonged than in fibers from WT littermates. Furthermore, some action potentials in the diseased fibers self-trigger. These defects occur because of decreases in the resting chloride and potassium conductances. Consistent with this, the expression of the muscle chloride channel, ClC-1, in Huntington disease muscle was compromised by improper splicing and a corresponding reduction in total Clcn1 (gene for ClC-1) mRNA. Additionally, the total Kcnj2 (gene for the Kir2.1 potassium channel) mRNA was reduced in disease muscle. The resulting muscle hyperexcitability causes involuntary and prolonged contractions that may contribute to the chorea, rigidity, and dystonia that characterize Huntington disease.
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Essential roles of mitochondrial depolarization in neuron loss through microglial activation and attraction toward neurons. Brain Res 2013; 1505:75-85. [PMID: 23415650 DOI: 10.1016/j.brainres.2013.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/04/2013] [Accepted: 02/05/2013] [Indexed: 12/17/2022]
Abstract
As life spans increased, neurodegenerative disorders that affect aging populations have also increased. Progressive neuronal loss in specific brain regions is the most common cause of neurodegenerative disease; however, key determinants mediating neuron loss are not fully understood. Using a model of mitochondrial membrane potential (ΔΨm) loss, we found only 25% cell loss in SH-SY5Y (SH) neuronal mono-cultures, but interestingly, 85% neuronal loss occurred when neurons were co-cultured with BV2 microglia. SH neurons overexpressing uncoupling protein 2 exhibited an increase in neuron-microglia interactions, which represent an early step in microglial phagocytosis of neurons. This result indicates that ΔΨm loss in SH neurons is an important contributor to recruitment of BV2 microglia. Notably, we show that ΔΨm loss in BV2 microglia plays a crucial role in microglial activation and phagocytosis of damaged SH neurons. Thus, our study demonstrates that ΔΨm loss in both neurons and microglia is a critical determinant of neuron loss. These findings also offer new insights into neuroimmunological and bioenergetical aspects of neurodegenerative disease.
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43
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An in vitro perspective on the molecular mechanisms underlying mutant huntingtin protein toxicity. Cell Death Dis 2012; 3:e382. [PMID: 22932724 PMCID: PMC3434668 DOI: 10.1038/cddis.2012.121] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Huntington's disease (HD) is a devastating neurodegenerative disorder whose main hallmark is brain atrophy. However, several peripheral organs are considerably affected and their symptoms may, in fact, manifest before those resulting from brain pathology. HD is of genetic origin and caused by a mutation in the huntingtin gene. The mutated protein has detrimental effects on cell survival, but whether the mutation leads to a gain of toxic function or a loss of function of the altered protein is still highly controversial. Most currently used in vitro models have been designed, to a large extent, to investigate the effects of the aggregation process in neuronal-like cells. However, as the pathology involves several other organs, new in vitro models are critically needed to take into account the deleterious effects of mutant huntingtin in peripheral tissues, and thus to identify new targets that could lead to more effective clinical interventions in the early course of the disease. This review aims to present current in vitro models of HD pathology and to discuss the knowledge that has been gained from these studies as well as the new in vitro tools that have been developed, which should reflect the more global view that we now have of the disease.
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Lee JK, Mathews K, Schlaggar B, Perlmutter J, Paulsen JS, Epping E, Burmeister L, Nopoulos P. Measures of growth in children at risk for Huntington disease. Neurology 2012; 79:668-74. [PMID: 22815549 DOI: 10.1212/wnl.0b013e3182648b65] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE The effect of mHTT on human development was examined by evaluating measures of growth in children at risk for Huntington disease (HD). METHODS Children at risk for HD with no manifest symptoms (no juvenile HD included) were enrolled and tested for gene expansion for research purposes only. Measurements of growth (height, weight, body mass index [BMI], and head circumference) in children tested as gene-expanded (n = 20, 7-18 years of age, CAG repeats ≥39) were compared to those of a large database of healthy children (n = 152, 7-18 years of age). RESULTS Gene-expanded children had significantly lower measures of head circumference, weight, and BMI. Head circumference was abnormally low even after correcting for height, suggesting a specific deficit in brain growth, rather than a global growth abnormality. CONCLUSIONS These results indicate that, compared to a control population, children who were estimated to be decades from HD diagnosis have significant differences in growth. Further, they suggest that mHTT may play a role in atypical somatic, and in particular, brain development.
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Affiliation(s)
- Jessica K Lee
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, USA.
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45
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Kumar P, Kalonia H, Kumar A. Possible GABAergic mechanism in the neuroprotective effect of gabapentin and lamotrigine against 3-nitropropionic acid induced neurotoxicity. Eur J Pharmacol 2012; 674:265-74. [DOI: 10.1016/j.ejphar.2011.11.030] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 11/12/2011] [Accepted: 11/16/2011] [Indexed: 11/29/2022]
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Naia L, Ribeiro MJ, Rego AC. Mitochondrial and metabolic-based protective strategies in Huntington's disease: the case of creatine and coenzyme Q. Rev Neurosci 2011; 23:13-28. [PMID: 22150069 DOI: 10.1515/rns.2011.060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 10/26/2011] [Indexed: 01/15/2023]
Abstract
Huntington's disease (HD) is a neurodegenerative genetic disorder caused by an expansion of CAG repeats in the HD gene encoding for huntingtin (Htt), resulting in progressive death of striatal neurons, with clinical symptoms of chorea, dementia and dramatic weight loss. Metabolic and mitochondrial dysfunction caused by the expanded polyglutamine sequence have been described along with other mechanisms of neurodegeneration previously described in human tissues and animal models of HD. In this review, we focus on mitochondrial and metabolic disturbances affecting both the central nervous system and peripheral cells, including mitochondrial DNA damage, mitochondrial complexes defects, loss of calcium homeostasis and transcriptional deregulation. Glucose abnormalities have also been described in peripheral tissues of HD patients and in HD animal and cellular models. Moreover, there are no effective neuroprotective treatments available in HD. Thus, we briefly discuss the role of creatine and coenzyme Q10 that target mitochondrial dysfunction and impaired bioenergetics and have been previously used in HD clinical trials.
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Affiliation(s)
- Luana Naia
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
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47
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Johri A, Calingasan NY, Hennessey TM, Sharma A, Yang L, Wille E, Chandra A, Beal MF. Pharmacologic activation of mitochondrial biogenesis exerts widespread beneficial effects in a transgenic mouse model of Huntington's disease. Hum Mol Genet 2011; 21:1124-37. [PMID: 22095692 DOI: 10.1093/hmg/ddr541] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
There is substantial evidence that impairment of peroxisome proliferator-activated receptor (PPAR)-γ-coactivator 1α (PGC-1α) levels and activity play an important role in Huntington's disease (HD) pathogenesis. We tested whether pharmacologic treatment with the pan-PPAR agonist bezafibrate would correct a deficiency of PGC-1α and exert beneficial effects in a transgenic mouse model of HD. We found that administration of bezafibrate in the diet restored levels of PGC-1α, PPARs and downstream genes to levels which occur in wild-type mice. There were significant improvements in phenotype and survival. In the striatum, astrogliosis and neuronal atrophy were attenuated and numbers of mitochondria were increased. Bezafibrate treatment prevented conversion of type I oxidative to type II glycolytic muscle fibers and increased the numbers of muscle mitochondria. Finally, bezafibrate rescued lipid accumulation and apparent vacuolization of brown adipose tissue in the HD mice. These findings provide strong evidence that treatment with bezafibrate exerts neuroprotective effects which may be beneficial in the treatment of HD.
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Affiliation(s)
- Ashu Johri
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York-Presbyterian Hospital, New York, NY 10065, USA.
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Hickey MA, Zhu C, Medvedeva V, Franich NR, Levine MS, Chesselet MF. Evidence for behavioral benefits of early dietary supplementation with CoEnzymeQ10 in a slowly progressing mouse model of Huntington's disease. Mol Cell Neurosci 2011; 49:149-57. [PMID: 22044764 DOI: 10.1016/j.mcn.2011.10.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 10/01/2011] [Accepted: 10/16/2011] [Indexed: 12/14/2022] Open
Abstract
Controversies surround the usefulness of Coenzyme Q10 (CoQ10) in Huntington's disease (HD), an autosomal dominant, fatal, neurodegenerative disease with no cure or disease modifying treatment. CoQ10, an endogenous substrate for electron transport and an anti-oxidant, has been shown in some but not all studies to improve symptoms and survival in mouse models of HD. Previous studies have been conducted in fast-progressing models that better mimic the juvenile forms of HD than the much more common middle-age onset form, possibly accounting for mixed results. Establishing the usefulness of CoQ10 to alter HD disease course in a model that better recapitulates the progressive features of the human disorder is important because clinical trials of CoQ10, which is safe and well tolerated, are being planned in patients. The CAG140 knock-in (KI) mouse model of HD in which an expanded (approximately 120) CAG repeat is inserted in the mouse gene provides a model of the mutation in the proper genomic and protein context. These mice display progressive motor, cognitive and emotional anomalies, transcriptional disturbances and late striatal degeneration. Homozygote mutant CAG140 KI mice and wild-type littermates were fed CoQ10 (0.2%, 0.6%) in chow, and behavioral and pathological markers of disease were examined. CoQ10 improved early behavioral deficits and normalized some transcriptional deficits without altering huntingtin aggregates in striatum. The lower dose (0.2%) was more beneficial than 0.6%. Similar to previous studies, this low dose also induced deleterious effects in open field and rotarod in WT mice, however these effects are of unclear clinical significance in view of the excellent safety profile of CoQ10 in humans. These data confirm that CoQ10 may be beneficial in HD but suggest that maximum benefit may be observed when treatment is begun at early stages of the disease and that dosage may be critical.
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Affiliation(s)
- Miriam A Hickey
- Department of Neurology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
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Roze E, Cahill E, Martin E, Bonnet C, Vanhoutte P, Betuing S, Caboche J. Huntington's Disease and Striatal Signaling. Front Neuroanat 2011; 5:55. [PMID: 22007160 PMCID: PMC3188786 DOI: 10.3389/fnana.2011.00055] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 08/04/2011] [Indexed: 12/05/2022] Open
Abstract
Huntington’s Disease (HD) is the most frequent neurodegenerative disease caused by an expansion of polyglutamines (CAG). The main clinical manifestations of HD are chorea, cognitive impairment, and psychiatric disorders. The transmission of HD is autosomal dominant with a complete penetrance. HD has a single genetic cause, a well-defined neuropathology, and informative pre-manifest genetic testing of the disease is available. Striatal atrophy begins as early as 15 years before disease onset and continues throughout the period of manifest illness. Therefore, patients could theoretically benefit from therapy at early stages of the disease. One important characteristic of HD is the striatal vulnerability to neurodegeneration, despite similar expression of the protein in other brain areas. Aggregation of the mutated Huntingtin (HTT), impaired axonal transport, excitotoxicity, transcriptional dysregulation as well as mitochondrial dysfunction, and energy deficits, are all part of the cellular events that underlie neuronal dysfunction and striatal death. Among these non-exclusive mechanisms, an alteration of striatal signaling is thought to orchestrate the downstream events involved in the cascade of striatal dysfunction.
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Affiliation(s)
- Emmanuel Roze
- UMRS 952, INSERM, UMR 7224, CNRS Université Pierre et Marie Curie - Paris-6 Paris, France
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50
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Bioenergetic dysfunction in Huntington's disease human cybrids. Exp Neurol 2011; 231:127-34. [PMID: 21684277 DOI: 10.1016/j.expneurol.2011.05.024] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 04/30/2011] [Accepted: 05/28/2011] [Indexed: 12/23/2022]
Abstract
In this work we studied the mitochondrial-associated metabolic pathways in Huntington's disease (HD) versus control (CTR) cybrids, a cell model in which the contribution of mitochondrial defects from patients is isolated. HD cybrids exhibited an interesting increase in ATP levels, when compared to CTR cybrids. Concomitantly, we observed increased glycolytic rate in HD cybrids, as revealed by increased lactate/pyruvate ratio, which was reverted after inhibition of glycolysis. A decrease in glucose-6-phosphate dehydrogenase activity in HD cybrids further indicated decreased rate of the pentose-phosphate pathway. ATP levels of HD cybrids were significantly decreased under glycolysis inhibition, which was accompanied by a decrease in phosphocreatine. Nevertheless, pyruvate supplementation could not recover HD cybrids' ATP or phosphocreatine levels, suggesting a dysfunction in mitochondrial use of that substrate. Oligomycin also caused a decrease in ATP levels, suggesting a partial support of ATP generation by the mitochondria. Nevertheless, mitochondrial NADH/NAD(t) levels were decreased in HD cybrids, which was correlated with a decrease in pyruvate dehydrogenase activity and protein expression, suggesting decreased tricarboxylic acid cycle (TCA) input from glycolysis. Interestingly, the activity of alpha-ketoglutarate dehydrogenase, a critical enzyme complex that links the TCA to amino acid synthesis and degradation, was increased in HD cybrids. In accordance, mitochondrial levels of glutamate were increased and alanine was decreased, whereas aspartate and glutamine levels were unchanged in HD cybrids. Conversely, malate dehydrogenase activity from total cell extracts was unchanged in HD cybrids. Our results suggest that inherent dysfunction of mitochondria from HD patients affects cellular bioenergetics in an otherwise functional nuclear background.
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