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Mitochondrial Apoptotic Signaling Involvement in Remodeling During Myogenesis and Skeletal Muscle Atrophy. Semin Cell Dev Biol 2023; 143:66-74. [PMID: 35241367 DOI: 10.1016/j.semcdb.2022.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/28/2022] [Accepted: 01/29/2022] [Indexed: 01/11/2023]
Abstract
Mitochondria play a major role in apoptotic signaling. In addition to its role in eliminating dysfunctional cells, mitochondrial apoptotic signaling is implicated as a key component of myogenic differentiation and skeletal muscle atrophy. For example, the activation of cysteine-aspartic proteases (caspases; CASP's) can aid in the initial remodeling stages of myogenic differentiation by cleaving protein kinases, transcription factors, and cytoskeletal proteins. Precise regulation of these signals is needed to prevent excessive cell disassemble and subsequent cell death. During skeletal muscle atrophy, the activation of CASP's and mitochondrial derived nucleases participate in myonuclear fragmentation, a potential loss of myonuclei, and cleavage of contractile structures within skeletal muscle. The B cell leukemia/lymphoma 2 (BCL2) family of proteins play a significant role in regulating myogenesis and skeletal muscle atrophy by governing the initiating steps of mitochondrial apoptotic signaling. This review discusses the role of mitochondrial apoptotic signaling in skeletal muscle remodeling during myogenic differentiation and skeletal muscle pathological states, including aging, disuse, and muscular dystrophy.
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Dickson E, Fryklund C, Soylu-Kucharz R, Sjögren M, Stenkula KG, Björkqvist M. Altered Adipocyte Cell Size Distribution Prior to Weight Loss in the R6/2 Model of Huntington's Disease. J Huntingtons Dis 2023; 12:253-266. [PMID: 37718850 DOI: 10.3233/jhd-230587] [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: 09/19/2023]
Abstract
BACKGROUND Metabolic alterations contribute to disease onset and prognosis of Huntington's disease (HD). Weight loss in the R6/2 mouse model of HD is a consistent feature, with onset in mid-to-late stage of disease. OBJECTIVE In the present study, we aimed to investigate molecular and functional changes in white adipose tissue (WAT) that occur at weight loss in R6/2 mice. We further elaborated on the effect of leptin-deficiency and early obesity in R6/2 mice. METHODS We performed analyses at 12 weeks of age; a time point that coincides with the start of weight loss in our R6/2 mouse colony. Gonadal (visceral) and inguinal (subcutaneous) WAT depot weights were monitored, as well as adipocyte size distribution. Response to isoprenaline-stimulated glycerol release and insulin-stimulated glucose uptake in adipocytes from gonadal WAT was assessed. RESULTS In R6/2 mice, WAT depot weights were comparable to wildtype (WT) mice, and the response to insulin and isoprenaline in gonadal adipocytes was unaltered. Leptin-deficient R6/2 mice exhibited distinct changes compared to leptin-deficient WT mice. At 12 weeks, female leptin-deficient R6/2 mice had reduced body weight accompanied by an increased proportion of smaller adipocytes, while in contrast; male mice displayed a shift towards larger adipocyte sizes without a significant body weight reduction at this timepoint. CONCLUSIONS We here show that there are early sex-specific changes in adipocyte cell size distribution in WAT of R6/2 mice and leptin-deficient R6/2 mice.
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Affiliation(s)
- Elna Dickson
- Brain Disease Biomarker Unit, Wallenberg Neuroscience Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Claes Fryklund
- Glucose Transport and Protein Trafficking, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Rana Soylu-Kucharz
- Brain Disease Biomarker Unit, Wallenberg Neuroscience Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Marie Sjögren
- Brain Disease Biomarker Unit, Wallenberg Neuroscience Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Karin G Stenkula
- Glucose Transport and Protein Trafficking, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Maria Björkqvist
- Brain Disease Biomarker Unit, Wallenberg Neuroscience Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
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3
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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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Skeletal Muscle Pathogenesis in Polyglutamine Diseases. Cells 2022; 11:cells11132105. [PMID: 35805189 PMCID: PMC9265456 DOI: 10.3390/cells11132105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/24/2022] [Accepted: 06/28/2022] [Indexed: 01/27/2023] Open
Abstract
Polyglutamine diseases are characterized by selective dysfunction and degeneration of specific types of neurons in the central nervous system. In addition, nonneuronal cells can also be affected as a consequence of primary degeneration or due to neuronal dysfunction. Skeletal muscle is a primary site of toxicity of polyglutamine-expanded androgen receptor, but it is also affected in other polyglutamine diseases, more likely due to neuronal dysfunction and death. Nonetheless, pathological processes occurring in skeletal muscle atrophy impact the entire body metabolism, thus actively contributing to the inexorable progression towards the late and final stages of disease. Skeletal muscle atrophy is well recapitulated in animal models of polyglutamine disease. In this review, we discuss the impact and relevance of skeletal muscle in patients affected by polyglutamine diseases and we review evidence obtained in animal models and patient-derived cells modeling skeletal muscle.
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Manjari S, Maity S, Poornima R, Yau SY, Vaishali K, Stellwagen D, Komal P. Restorative action of vitamin D3 on motor dysfunction through enhancement of neurotrophins and antioxidant expression in the striatum. Neuroscience 2022; 492:67-81. [DOI: 10.1016/j.neuroscience.2022.03.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/27/2022] [Accepted: 03/29/2022] [Indexed: 01/21/2023]
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Hypothalamic expression of huntingtin causes distinct metabolic changes in Huntington's disease mice. Mol Metab 2022; 57:101439. [PMID: 35007790 PMCID: PMC8814380 DOI: 10.1016/j.molmet.2022.101439] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 01/05/2022] [Indexed: 11/29/2022] Open
Abstract
Objective In Huntington's disease (HD), the disease-causing huntingtin (HTT) protein is ubiquitously expressed and causes both central and peripheral pathology. In clinical HD, a higher body mass index has been associated with slower disease progression, indicating the role of metabolic changes in disease pathogenesis. Underlying mechanisms of metabolic changes in HD remain poorly understood, but recent studies suggest the involvement of hypothalamic dysfunction. The present study aimed to investigate whether modulation of hypothalamic HTT levels would affect metabolic phenotype and disease features in HD using mouse models. Methods We used the R6/2 and BACHD mouse models that express different lengths of mutant HTT to develop lean- and obese phenotypes, respectively. We utilized adeno-associated viral vectors to overexpress either mutant or wild-type HTT in the hypothalamus of R6/2, BACHD, and their wild-type littermates. The metabolic phenotype was assessed by body weight measurements over time and body composition analysis using dual-energy x-ray absorptiometry at the endpoint. R6/2 mice were further characterized using behavioral analyses, including rotarod, nesting-, and hindlimb clasping tests during early- and late-time points of disease progression. Finally, gene expression analysis was performed in R6/2 mice and wild-type littermates in order to assess transcriptional changes in the hypothalamus and adipose tissue. Results Hypothalamic overexpression of mutant HTT induced significant gender-affected body weight gain in all models, including wild-type mice. In R6/2 females, early weight gain shifted to weight loss during the corresponding late stage of disease despite increased fat accumulation. Body weight changes were accompanied by behavioral alterations. During the period of early weight gain, R6/2 mice displayed a comparable locomotor capacity to wild-type mice. When assessing behavior just prior to weight loss onset in R6/2 mice, decreased locomotor performance was observed in R6/2 females with hypothalamic overexpression of mutant HTT. Transcriptional downregulation of beta-3 adrenergic receptor (B3AR), adipose triglyceride lipase (ATGL), and peroxisome proliferator-activated receptor-gamma (PPARγ) in gonadal white adipose tissue was accompanied by distinct alterations in hypothalamic gene expression profiles in R6/2 females after mutant HTT overexpression. No significant effect on metabolic phenotype in R6/2 was seen in response to wild-type HTT overexpression. Conclusions Taken together, our findings provide further support for the role of HTT in metabolic control via hypothalamic neurocircuits. Understanding the specific central neurocircuits and their peripheral link underlying metabolic imbalance in HD may open up avenues for novel therapeutic interventions. Overexpression of hypothalamic huntingtin affects weight in Huntington's disease mice. Hypothalamic huntingtin expression results in gene expression changes in white fat and the hypothalamus. Hypothalamic huntingtin cannot prevent late-stage weight loss in R6/2 mice.
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7
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Simpson B, Rich MM, Voss AA, Talmadge RJ. Acetylcholine receptor subunit expression in Huntington's disease mouse muscle. Biochem Biophys Rep 2021; 28:101182. [PMID: 34926838 PMCID: PMC8649948 DOI: 10.1016/j.bbrep.2021.101182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 12/01/2021] [Indexed: 10/26/2022] Open
Abstract
Huntington's disease (HD) causes neurological impairments, as well as muscle dysfunction, including smaller neuromuscular junctions (NMJs). This study assessed the expression levels of the subunits of the nicotinic acetylcholine receptor (nAChR) in muscles of the R6/2 mouse model of HD. Based on our previous findings of reduced NMJ size in R6/2 mice, it was hypothesized that muscles from R6/2 mice would also show an altered expression pattern of nAChR subunits compared to wild-type (WT) mice. Therefore, the mRNA levels of nAChR subunits were quantified in R6/2 and WT mouse muscles using qRT-PCR. Denervated muscles from WT mice served as positive controls for alterations in nAChR expression. Although some changes in nAChR subunit expression occurred in R6/2 muscles, the expression levels closely resembled WT. However, the expression of nAChR subunit-ε (Chrne) was significantly decreased in R6/2 muscles relative to WT. This study demonstrates that only minor changes in nAChR subunit expression occurs in R6/2 mouse muscles and that reduction in Chrne expression may be related to a reduction in NMJ size in R6/mice.
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Affiliation(s)
- Briana Simpson
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA, 91768, USA
| | - Mark M Rich
- Department of Neuroscience, Cell Biology & Physiology, Wright State University, Dayton, OH, 45435, USA
| | - Andrew A Voss
- Department of Biological Sciences, Wright State University, Dayton, OH, 45435, USA
| | - Robert J Talmadge
- Department of Biological Sciences, California State Polytechnic University, Pomona, CA, 91768, USA
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8
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Story D, Gallien J, Al-Gharaibeh A, Sandstrom M, Rossignol J, Dunbar GL. Housing R6/2 Mice with Wild-Type Littermates Increases Lifespan. J Huntingtons Dis 2021; 10:455-458. [PMID: 34511507 DOI: 10.3233/jhd-210474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The R6/2 murine model of Huntington's disease (HD) is extensively used in HD research. The current study replicates and extends previous work assessing the impact of housing R6/2 mice with healthy wild-type (WT) littermates on disease progression. The current study extends the previous finding by including male cohorts and the use of a standard diet and water regimen, as opposed to the enhanced diet used in the previous study. This study found that the inclusion of healthy wild-type (WT) littermates, alone, improved survivabilty in R6/2 mice, but did not have a significant impact on weight loss.
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Affiliation(s)
- Darren Story
- Field Neurosciences Institute for Restorative Neurology, Central Michigan University, Mount Pleasant, MI, USA.,Department of Psychology, Central Michigan University, Mount Pleasant, MI, USA
| | - John Gallien
- Field Neurosciences Institute for Restorative Neurology, Central Michigan University, Mount Pleasant, MI, USA.,Program in Neuroscience, Central Michigan University, Mount Pleasant, MI, USA
| | - Abeer Al-Gharaibeh
- Field Neurosciences Institute for Restorative Neurology, Central Michigan University, Mount Pleasant, MI, USA.,Program in Neuroscience, Central Michigan University, Mount Pleasant, MI, USA
| | - Michael Sandstrom
- Program in Neuroscience, Central Michigan University, Mount Pleasant, MI, USA.,Department of Psychology, Central Michigan University, Mount Pleasant, MI, USA
| | - Julien Rossignol
- Field Neurosciences Institute for Restorative Neurology, Central Michigan University, Mount Pleasant, MI, USA.,Program in Neuroscience, Central Michigan University, Mount Pleasant, MI, USA.,College of Medicine, Central Michigan University, Mount Pleasant, MI, USA
| | - Gary L Dunbar
- Field Neurosciences Institute for Restorative Neurology, Central Michigan University, Mount Pleasant, MI, USA.,Program in Neuroscience, Central Michigan University, Mount Pleasant, MI, USA.,Department of Psychology, Central Michigan University, Mount Pleasant, MI, USA.,Field Neurosciences Institute, St. Mary's of Michigan, Saginaw, MI, USA
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9
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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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10
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Gonchar OO, Maznychenko AV, Klyuchko OM, Mankovska IM, Butowska K, Borowik A, Piosik J, Sokolowska I. C 60 Fullerene Reduces 3-Nitropropionic Acid-Induced Oxidative Stress Disorders and Mitochondrial Dysfunction in Rats by Modulation of p53, Bcl-2 and Nrf2 Targeted Proteins. Int J Mol Sci 2021; 22:ijms22115444. [PMID: 34064070 PMCID: PMC8196695 DOI: 10.3390/ijms22115444] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/16/2021] [Accepted: 05/19/2021] [Indexed: 01/23/2023] Open
Abstract
C60 fullerene as a potent free radical scavenger and antioxidant could be a beneficial means for neurodegenerative disease prevention or cure. The aim of the study was to define the effects of C60 administration on mitochondrial dysfunction and oxidative stress disorders in a 3-nitropropionic acid (3-NPA)-induced rat model of Huntington’s disease. Animals received 3-NPA (30 mg/kg i.p.) once a day for 3 consecutive days. C60 was applied at a dose of 0.5 mg/kg of body weight, i.p. daily over 5 days before (C60 pre-treatment) and after 3-NPA exposure (C60 post-treatment). Oxidative stress biomarkers, the activity of respiratory chain enzymes, the level of antioxidant defense, and pro- and antiapoptotic markers were analyzed in the brain and skeletal muscle mitochondria. The nuclear and cytosol Nrf2 protein expression, protein level of MnSOD, γ-glutamate-cysteine ligase (γ-GCLC), and glutathione-S-transferase (GSTP) as Nrf2 targets were evaluated. Our results indicated that C60 can prevent 3-NPA-induced mitochondrial dysfunction through the restoring of mitochondrial complexes’ enzyme activity, ROS scavenging, modulating of pro/antioxidant balance and GSH/GSSG ratio, as well as inhibition of mitochondria-dependent apoptosis through the limitation of p53 mitochondrial translocation and increase in Bcl-2 protein expression. C60 improved mitochondrial protection by strengthening the endogenous glutathione system via glutathione biosynthesis by up-regulating Nrf2 nuclear accumulation as well as GCLC and GSTP protein level.
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Affiliation(s)
- Olga O. Gonchar
- Department of Hypoxic States and Department of Movements Physiology, Bogomoletz Institute of Physiology, Bogomoletz Str. 4, 01024 Kyiv, Ukraine; (O.O.G.); (I.M.M.)
| | - Andriy V. Maznychenko
- Department of Hypoxic States and Department of Movements Physiology, Bogomoletz Institute of Physiology, Bogomoletz Str. 4, 01024 Kyiv, Ukraine; (O.O.G.); (I.M.M.)
- Department of Physical Education, Gdansk University of Physical Education and Sport, Kazimierza Gorskiego Str. 1, 80-336 Gdansk, Poland;
- Correspondence:
| | - Olena M. Klyuchko
- Department of Electronics, National Aviation University, L. Huzar Ave. 1, 03058 Kyiv, Ukraine;
| | - Iryna M. Mankovska
- Department of Hypoxic States and Department of Movements Physiology, Bogomoletz Institute of Physiology, Bogomoletz Str. 4, 01024 Kyiv, Ukraine; (O.O.G.); (I.M.M.)
| | - Kamila Butowska
- Laboratory of Biophysics, Intercollegiate Faculty of Biotechnology UG-MUG, Abrahama 58, 80-307 Gdansk, Poland; (K.B.); (A.B.); (J.P.)
| | - Agnieszka Borowik
- Laboratory of Biophysics, Intercollegiate Faculty of Biotechnology UG-MUG, Abrahama 58, 80-307 Gdansk, Poland; (K.B.); (A.B.); (J.P.)
| | - Jacek Piosik
- Laboratory of Biophysics, Intercollegiate Faculty of Biotechnology UG-MUG, Abrahama 58, 80-307 Gdansk, Poland; (K.B.); (A.B.); (J.P.)
| | - Inna Sokolowska
- Department of Physical Education, Gdansk University of Physical Education and Sport, Kazimierza Gorskiego Str. 1, 80-336 Gdansk, Poland;
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11
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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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12
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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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13
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Alexander-Floyd J, Haroon S, Ying M, Entezari AA, Jaeger C, Vermulst M, Gidalevitz T. Unexpected cell type-dependent effects of autophagy on polyglutamine aggregation revealed by natural genetic variation in C. elegans. BMC Biol 2020; 18:18. [PMID: 32093691 PMCID: PMC7038566 DOI: 10.1186/s12915-020-0750-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 02/13/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Monogenic protein aggregation diseases, in addition to cell selectivity, exhibit clinical variation in the age of onset and progression, driven in part by inter-individual genetic variation. While natural genetic variants may pinpoint plastic networks amenable to intervention, the mechanisms by which they impact individual susceptibility to proteotoxicity are still largely unknown. RESULTS We have previously shown that natural variation modifies polyglutamine (polyQ) aggregation phenotypes in C. elegans muscle cells. Here, we find that a genomic locus from C. elegans wild isolate DR1350 causes two genetically separable aggregation phenotypes, without changing the basal activity of muscle proteostasis pathways known to affect polyQ aggregation. We find that the increased aggregation phenotype was due to regulatory variants in the gene encoding a conserved autophagy protein ATG-5. The atg-5 gene itself conferred dosage-dependent enhancement of aggregation, with the DR1350-derived allele behaving as hypermorph. Surprisingly, increased aggregation in animals carrying the modifier locus was accompanied by enhanced autophagy activation in response to activating treatment. Because autophagy is expected to clear, not increase, protein aggregates, we activated autophagy in three different polyQ models and found a striking tissue-dependent effect: activation of autophagy decreased polyQ aggregation in neurons and intestine, but increased it in the muscle cells. CONCLUSIONS Our data show that cryptic natural variants in genes encoding proteostasis components, although not causing detectable phenotypes in wild-type individuals, can have profound effects on aggregation-prone proteins. Clinical applications of autophagy activators for aggregation diseases may need to consider the unexpected divergent effects of autophagy in different cell types.
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Affiliation(s)
- J Alexander-Floyd
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Present Address: Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - S Haroon
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - M Ying
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
| | - A A Entezari
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Current Address: Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - C Jaeger
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Current Address: Department of Neuroradiology, Technical University of Munich, Munich, Germany
| | - M Vermulst
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Current Address: Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
| | - T Gidalevitz
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA.
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14
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Pinho BR, Duarte AI, Canas PM, Moreira PI, Murphy MP, Oliveira JMA. The interplay between redox signalling and proteostasis in neurodegeneration: In vivo effects of a mitochondria-targeted antioxidant in Huntington's disease mice. Free Radic Biol Med 2020; 146:372-382. [PMID: 31751762 PMCID: PMC6970224 DOI: 10.1016/j.freeradbiomed.2019.11.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/14/2019] [Accepted: 11/16/2019] [Indexed: 12/22/2022]
Abstract
Abnormal protein homeostasis (proteostasis), dysfunctional mitochondria, and aberrant redox signalling are often associated in neurodegenerative disorders, such as Huntington's (HD), Alzheimer's and Parkinson's diseases. It remains incompletely understood, however, how changes in redox signalling affect proteostasis mechanisms, including protein degradation pathways and unfolded protein responses (UPR). Here we address this open question by investigating the interplay between redox signalling and proteostasis in a mouse model of HD, and by examining the in vivo effects of the mitochondria-targeted antioxidant MitoQ. We performed behavioural tests in wild-type and R6/2 HD mice, examined markers of oxidative stress, UPR activation, and the status of key protein degradation pathways in brain and peripheral tissues. We show that R6/2 mice present widespread markers of oxidative stress, with tissue-specific changes in proteostasis that were more pronounced in the brain and muscle than in the liver. R6/2 mice presented increased levels of cytosolic and mitochondrial chaperones, particularly in muscle, indicating UPR activation. Treatment with MitoQ significantly ameliorated fine motor control of R6/2 mice, and reduced markers of oxidative damage in muscle. Additionally, MitoQ attenuated overactive autophagy induction in the R6/2 muscle, which has been associated with muscle wasting. Treatment with MitoQ did not alter autophagy markers in the brain, in agreement with its low brain bioavailability, which limits the risk of impairing neuronal protein clearance mechanisms. This study supports the hypotheses that abnormal redox signalling in muscle contributes to altered proteostasis and motor impairment in HD, and that redox interventions can improve muscle performance, highlighting the importance of peripheral therapeutics in HD.
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Affiliation(s)
- Brígida R Pinho
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Ana I Duarte
- CNC - Center for Neuroscience & Cell Biology, University of Coimbra, Coimbra, Portugal; Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal
| | - Paula M Canas
- CNC - Center for Neuroscience & Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Paula I Moreira
- CNC - Center for Neuroscience & Cell Biology, University of Coimbra, Coimbra, Portugal; Institute of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, CB20XY, UK
| | - Jorge M A Oliveira
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, Porto, Portugal; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK.
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15
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Child DD, Lee JH, Pascua CJ, Chen YH, Mas Monteys A, Davidson BL. Cardiac mTORC1 Dysregulation Impacts Stress Adaptation and Survival in Huntington's Disease. Cell Rep 2019; 23:1020-1033. [PMID: 29694882 PMCID: PMC5967646 DOI: 10.1016/j.celrep.2018.03.117] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 01/05/2018] [Accepted: 03/26/2018] [Indexed: 12/27/2022] Open
Abstract
Huntington’s disease (HD) is a dominantly inherited neurological disorder caused by CAG-repeat expansion in exon 1 of Huntingtin (HTT). But in addition to the neurological disease, mutant HTT (mHTT), which is ubiquitously expressed, impairs other organ systems. Indeed, epidemiological and animal model studies suggest higher incidence of and mortality from heart disease in HD. Here, we show that the protein complex mTORC1 is dysregulated in two HD mouse models through a mechanism that requires intrinsic mHTT expression. Moreover, restoring cardiac mTORC1 activity with constitutively active Rheb prevents mortality and relieves the mHTT-induced block to hypertrophic adaptation to cardiac stress. Finally, we show that chronic mTORC1 dysregulation is due in part to mislocalization of endogenous Rheb. These data provide insight into the increased cardiac-related mortality of HD patients, with cardiac mHTT expression inhibiting mTORC1 activity, limiting heart growth, and decreasing the heart’s ability to compensate to chronic stress.
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Affiliation(s)
- Daniel D Child
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA; The Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, USA
| | - John H Lee
- Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA
| | - Christine J Pascua
- Division of Cardiology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Yong Hong Chen
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Alejandro Mas Monteys
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Beverly L Davidson
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA; The Perelman School of Medicine, The University of Pennsylvania, Philadelphia, PA, USA.
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16
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Sjögren M, Soylu-Kucharz R, Dandunna U, Stan TL, Cavalera M, Sandelius Å, Zetterberg H, Björkqvist M. Leptin deficiency reverses high metabolic state and weight loss without affecting central pathology in the R6/2 mouse model of Huntington's disease. Neurobiol Dis 2019; 132:104560. [PMID: 31419548 DOI: 10.1016/j.nbd.2019.104560] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 06/13/2019] [Accepted: 07/30/2019] [Indexed: 11/18/2022] Open
Abstract
Body weight has been shown to be a predictor of clinical progression in Huntington's disease (HD). Alongside widespread neuronal pathology, both HD patients and the R6/2 mouse model of HD exhibit weight loss and increased energy expenditure, providing a rationale for targeting whole-body energy metabolism in HD. Leptin-deficient mice display low energy expenditure and increased body weight. We therefore hypothesized that normalizing energy metabolism in R6/2 mice, utilizing leptin- deficiency, would lead to a slower disease progression in the R6/2 mouse. In this study, we show that R6/2 mice on a leptin-deficient genetic background display increased body weight and increased fat mass compared to R6/2 mice, as well as wild type littermates. The increased body weight was accompanied by low energy expenditure, illustrated by a reduction in respiratory exchange rate. Leptin-deficient R6/2 mice had large white adipocytes with white adipocyte gene expression characteristics, in contrast to white adipose tissue in R6/2 mice, where white adipose tissue showed signs of browning. Leptin-deficient R6/2 mice did not exhibit improved neuropathological measures. Our results indicate that lowering energy metabolism in HD, by increasing fat mass and reducing respiratory exchange rate, is not sufficient to affect neuropathology. Further studies targeting energy metabolism in HD are warranted.
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Affiliation(s)
- Marie Sjögren
- Wallenberg Neuroscience Center, Brain Disease Biomarker Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden.
| | - Rana Soylu-Kucharz
- Wallenberg Neuroscience Center, Brain Disease Biomarker Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
| | - Unali Dandunna
- Wallenberg Neuroscience Center, Brain Disease Biomarker Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
| | - Tiberiu Loredan Stan
- Wallenberg Neuroscience Center, Brain Disease Biomarker Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
| | - Michele Cavalera
- Department of Clinical Sciences, Cardiovascular Research, Translational Studies, Lund University, Malmö, Sweden
| | - Åsa Sandelius
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden
| | - Henrik Zetterberg
- Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, The Sahlgrenska Academy at University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom; UK Dementia Research Institute at UCL, London, United Kingdom
| | - Maria Björkqvist
- Wallenberg Neuroscience Center, Brain Disease Biomarker Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
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17
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Rodinova M, Krizova J, Stufkova H, Bohuslavova B, Askeland G, Dosoudilova Z, Juhas S, Juhasova J, Ellederova Z, Zeman J, Eide L, Motlik J, Hansikova H. Deterioration of mitochondrial bioenergetics and ultrastructure impairment in skeletal muscle of a transgenic minipig model in the early stages of Huntington's disease. Dis Model Mech 2019; 12:dmm.038737. [PMID: 31278192 PMCID: PMC6679385 DOI: 10.1242/dmm.038737] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 06/18/2019] [Indexed: 01/08/2023] Open
Abstract
Skeletal muscle wasting and atrophy is one of the more severe clinical impairments resulting from the progression of Huntington's disease (HD). Mitochondrial dysfunction may play a significant role in the etiology of HD, but the specific condition of mitochondria in muscle has not been widely studied during the development of HD. To determine the role of mitochondria in skeletal muscle during the early stages of HD, we analyzed quadriceps femoris muscle from 24-, 36-, 48- and 66-month-old transgenic minipigs that expressed the N-terminal portion of mutated human huntingtin protein (TgHD) and age-matched wild-type (WT) siblings. We found altered ultrastructure of TgHD muscle tissue and mitochondria. There was also significant reduction of activity of citrate synthase and respiratory chain complexes (RCCs) I, II and IV, decreased quantity of oligomycin-sensitivity conferring protein (OSCP) and the E2 subunit of pyruvate dehydrogenase (PDHE2), and differential expression of optic atrophy 1 protein (OPA1) and dynamin-related protein 1 (DRP1) in the skeletal muscle of TgHD minipigs. Statistical analysis identified several parameters that were dependent only on HD status and could therefore be used as potential biomarkers of disease progression. In particular, the reduction of biomarker RCCII subunit SDH30 quantity suggests that similar pathogenic mechanisms underlie disease progression in TgHD minipigs and HD patients. The perturbed biochemical phenotype was detectable in TgHD minipigs prior to the development of ultrastructural changes and locomotor impairment, which become evident at the age of 48 months. Mitochondrial disturbances may contribute to energetic depression in skeletal muscle in HD, which is in concordance with the mobility problems observed in this model.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Marie Rodinova
- Laboratory for Study of Mitochondrial Disorders, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12108 Prague 2, Czech Republic
| | - Jana Krizova
- Laboratory for Study of Mitochondrial Disorders, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12108 Prague 2, Czech Republic
| | - Hana Stufkova
- Laboratory for Study of Mitochondrial Disorders, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12108 Prague 2, Czech Republic
| | - Bozena Bohuslavova
- Laboratory of Cell Regeneration and Cell Plasticity, Institute of Animal Physiology and Genetics AS CR, 27721 Liběchov, Czech Republic
| | - Georgina Askeland
- Department of Medical Biochemistry, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway
| | - Zaneta Dosoudilova
- Laboratory for Study of Mitochondrial Disorders, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12108 Prague 2, Czech Republic
| | - Stefan Juhas
- Laboratory of Cell Regeneration and Cell Plasticity, Institute of Animal Physiology and Genetics AS CR, 27721 Liběchov, Czech Republic
| | - Jana Juhasova
- Laboratory of Cell Regeneration and Cell Plasticity, Institute of Animal Physiology and Genetics AS CR, 27721 Liběchov, Czech Republic
| | - Zdenka Ellederova
- Laboratory of Cell Regeneration and Cell Plasticity, Institute of Animal Physiology and Genetics AS CR, 27721 Liběchov, Czech Republic
| | - Jiri Zeman
- Laboratory for Study of Mitochondrial Disorders, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12108 Prague 2, Czech Republic
| | - Lars Eide
- Department of Medical Biochemistry, University of Oslo and Oslo University Hospital, 0372 Oslo, Norway
| | - Jan Motlik
- Laboratory of Cell Regeneration and Cell Plasticity, Institute of Animal Physiology and Genetics AS CR, 27721 Liběchov, Czech Republic
| | - Hana Hansikova
- Laboratory for Study of Mitochondrial Disorders, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12108 Prague 2, Czech Republic
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18
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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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19
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Normalizing glucocorticoid levels attenuates metabolic and neuropathological symptoms in the R6/2 mouse model of huntington's disease. Neurobiol Dis 2018; 121:214-229. [PMID: 30292559 DOI: 10.1016/j.nbd.2018.09.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 09/13/2018] [Accepted: 09/30/2018] [Indexed: 02/08/2023] Open
Abstract
Huntington's disease (HD) is a fatal genetic neurological disorder caused by a mutation in the human Huntingtin (HTT) gene. This mutation confers a toxic gain of function of the encoded mutant huntingtin (mHTT) protein, leading to widespread neuropathology including the formation of mHTT-positive inclusion bodies, gene dysregulation, reduced levels of adult dentate gyrus neurogenesis and neuron loss throughout many regions of the brain. Additionally, because HTT is ubiquitously expressed, several peripheral tissues are also affected. HD patients suffer from progressive motor, cognitive, psychiatric, and metabolic symptoms, including weight loss and skeletal muscle wasting. HD patients also show neuroendocrine changes including a robust, significant elevation in circulating levels of the glucocorticoid, cortisol. Previously, we confirmed that the R6/2 mouse model of HD exhibits elevated corticosterone (the rodent homolog of cortisol) levels and demonstrated that experimentally elevated corticosterone exacerbates R6/2 HD symptomology, resulting in severe and rapid weight loss and a shorter latency to death. Given that efficacious therapeutics are lacking for HD, here we investigated whether normalizing glucocorticoid levels could serve as a viable therapeutic approach for this disease. We tested the hypothesis that normalizing glucocorticoids to wild-type levels would ameliorate HD symptomology. Wild-type (WT) and transgenic R6/2 mice were allocated to three treatment groups: 1) adrenalectomy with normalized, WT-level corticosterone replacement (10 μg/ml), 2) adrenalectomy with high HD-level corticosterone replacement (35 μg/ml), or 3) sham surgery with no corticosterone replacement. Normalizing corticosterone to WT levels led to an improvement in metabolic rate in male R6/2 mice, as indicated by indirect calorimetry, including a reduction in oxygen consumption and normalization of respiratory exchange ratio values (p < .05 for both). Normalizing corticosterone also ameliorated brain atrophy in female R6/2 mice and skeletal muscle wasting in both male and female R6/2 mice (p < .05 for all). Female R6/2 mice given WT-level corticosterone replacement also showed a reduction in HD neuropathological markers, including a reduction in mHTT inclusion burden in the striatum, cortex, and hippocampus (p < .05 for all). This data illustrates that ameliorating glucocorticoid dysregulation leads to a significant improvement in HD symptomology in the R6/2 mouse model and suggests that cortisol-reducing therapeutics may be of value in improving HD patient quality of life.
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20
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Duarte AI, Sjögren M, Santos MS, Oliveira CR, Moreira PI, Björkqvist M. Dual Therapy with Liraglutide and Ghrelin Promotes Brain and Peripheral Energy Metabolism in the R6/2 Mouse Model of Huntington's Disease. Sci Rep 2018; 8:8961. [PMID: 29895889 PMCID: PMC5997749 DOI: 10.1038/s41598-018-27121-w] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 05/29/2018] [Indexed: 01/14/2023] Open
Abstract
Neuronal loss alongside altered energy metabolism, are key features of Huntington’s disease (HD) pathology. The orexigenic gut-peptide hormone ghrelin is known to stimulate appetite and affect whole body energy metabolism. Liraglutide is an efficient anti-type 2 diabetes incretin drug, with neuroprotective effects alongside anorectic properties. Combining liraglutide with the orexigenic peptide ghrelin may potentially promote brain/cognitive function in HD. The R6/2 mouse model of HD exhibits progressive central pathology, weight loss, deranged glucose metabolism, skeletal muscle atrophy and altered body composition. In this study, we targeted energy metabolism in R6/2 mice using a co-administration of liraglutide and ghrelin. We investigated their effect on brain cortical hormone-mediated intracellular signalling pathways, metabolic and apoptotic markers, and the impact on motor function in HD. We here demonstrate that liraglutide, alone or together with ghrelin (subcutaneous daily injections of 150 µg/kg (ghrelin) and 0.2 mg/kg (liraglutide), for 2 weeks), normalized glucose homeostatic features in the R6/2 mouse, without substantially affecting body weight or body composition. Liraglutide alone decreased brain cortical active GLP-1 and IGF-1 levels in R6/2 mice, alongside higher ADP levels. Liraglutide plus ghrelin decreased brain insulin, lactate, AMP and cholesterol levels in R6/2 mice. Taken together, our findings encourage further studies targeting energy metabolism in HD.
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Affiliation(s)
- Ana I Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal. .,Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Coimbra, Portugal. .,Brain Disease Biomarker Unit, Department of Experimental Medical Sciences, Wallenberg Neuroscience Center, Lund University, Lund, Sweden.
| | - Marie Sjögren
- Brain Disease Biomarker Unit, Department of Experimental Medical Sciences, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
| | - Maria S Santos
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Life Sciences Department, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal
| | - Catarina R Oliveira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Laboratory of Biochemistry, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Paula I Moreira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Laboratory of Physiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Maria Björkqvist
- Brain Disease Biomarker Unit, Department of Experimental Medical Sciences, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
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21
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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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22
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Manfré G, Clemensson EKH, Kyriakou EI, Clemensson LE, van der Harst JE, Homberg JR, Nguyen HP. The BACHD Rat Model of Huntington Disease Shows Specific Deficits in a Test Battery of Motor Function. Front Behav Neurosci 2017; 11:218. [PMID: 29163089 PMCID: PMC5675855 DOI: 10.3389/fnbeh.2017.00218] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 10/19/2017] [Indexed: 02/01/2023] Open
Abstract
Rationale: Huntington disease (HD) is a progressive neurodegenerative disorder characterized by motor, cognitive and neuropsychiatric symptoms. HD is usually diagnosed by the appearance of motor deficits, resulting in skilled hand use disruption, gait abnormality, muscle wasting and choreatic movements. The BACHD transgenic rat model for HD represents a well-established transgenic rodent model of HD, offering the prospect of an in-depth characterization of the motor phenotype. Objective: The present study aims to characterize different aspects of motor function in BACHD rats, combining classical paradigms with novel high-throughput behavioral phenotyping. Methods: Wild-type (WT) and transgenic animals were tested longitudinally from 2 to 12 months of age. To measure fine motor control, rats were challenged with the pasta handling test and the pellet reaching test. To evaluate gross motor function, animals were assessed by using the holding bar and the grip strength tests. Spontaneous locomotor activity and circadian rhythmicity were assessed in an automated home-cage environment, namely the PhenoTyper. We then integrated existing classical methodologies to test motor function with automated home-cage assessment of motor performance. Results: BACHD rats showed strong impairment in muscle endurance at 2 months of age. Altered circadian rhythmicity and locomotor activity were observed in transgenic animals. On the other hand, reaching behavior, forepaw dexterity and muscle strength were unaffected. Conclusions: The BACHD rat model exhibits certain features of HD patients, like muscle weakness and changes in circadian behavior. We have observed modest but clear-cut deficits in distinct motor phenotypes, thus confirming the validity of this transgenic rat model for treatment and drug discovery purposes.
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Affiliation(s)
- Giuseppe Manfré
- Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Center, Nijmegen, Netherlands.,Noldus Information Technology BV, Wageningen, Netherlands.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Erik K H Clemensson
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.,Centre of Rare Diseases, University of Tübingen, Tübingen, Germany
| | - Elisavet I Kyriakou
- Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Center, Nijmegen, Netherlands.,Noldus Information Technology BV, Wageningen, Netherlands.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Laura E Clemensson
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.,Centre of Rare Diseases, University of Tübingen, Tübingen, Germany
| | - Johanneke E van der Harst
- Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Center, Nijmegen, Netherlands.,Noldus Information Technology BV, Wageningen, Netherlands
| | - Judith R Homberg
- Donders Institute for Brain, Cognition and Behaviour, Department of Cognitive Neuroscience, Radboud University Medical Center, Nijmegen, Netherlands
| | - Huu Phuc Nguyen
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany.,Centre of Rare Diseases, University of Tübingen, Tübingen, Germany
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23
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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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Sjögren M, Duarte AI, McCourt AC, Shcherbina L, Wierup N, Björkqvist M. Ghrelin rescues skeletal muscle catabolic profile in the R6/2 mouse model of Huntington's disease. Sci Rep 2017; 7:13896. [PMID: 29066728 PMCID: PMC5654969 DOI: 10.1038/s41598-017-13713-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/27/2017] [Indexed: 12/14/2022] Open
Abstract
Accumulating evidence suggests altered energy metabolism as a key feature in Huntington’s disease (HD) pathology. Hyper-catabolism, including weight loss and muscle atrophy, is seen in HD patients and HD mouse models. Metabolic hormones are key players, not only in energy metabolism, but also in neurodegenerative processes. Ghrelin, a gut peptide-hormone, plays an important role in regulating energy metabolism, stimulating appetite, and affects brain function and increases neuronal survival. The R6/2 mouse model of HD has previously been shown to exhibit progressive weight loss, dysregulated glucose metabolism, skeletal muscle atrophy and altered body composition. In this study, we targeted energy metabolism in R6/2 mice using ghrelin administration, with the primary aim to delay weight loss and reduce muscle atrophy. We also evaluated glucose metabolism and behaviour. We here demonstrate that ghrelin administration (subcutaneous 150 μg/kg daily injections) for 4 weeks, reversed the catabolic gene expression profile (increased expression of Caspase 8, Traf-5 and Creb1) seen in R6/2 mouse skeletal muscle. Skeletal muscle morphology was also improved with ghrelin, and importantly, ghrelin administration normalized behavioural deficits in R6/2 mice. Taken together, our findings encourage further studies targeting metabolism in HD.
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Affiliation(s)
- Marie Sjögren
- Wallenberg Neuroscience Center, Department of Experimental Medical Sciences, Brain Disease Biomarker Unit, Lund University, Lund, Sweden.
| | - Ana I Duarte
- Wallenberg Neuroscience Center, Department of Experimental Medical Sciences, Brain Disease Biomarker Unit, Lund University, Lund, Sweden.,CNC - Center for Neuroscience and Cell Biology, Rua Larga, Faculty of Medicine (Pólo 1, 1st Floor), University of Coimbra, 3004-517, Coimbra, Portugal.,Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão - Pólo II, Rua D. Francisco de Lemos, 3030-789, Coimbra, Portugal
| | - Andrew C McCourt
- Wallenberg Neuroscience Center, Department of Experimental Medical Sciences, Brain Disease Biomarker Unit, Lund University, Lund, Sweden
| | - Liliya Shcherbina
- Lund University Diabetes Centre, Neuroendocrine Cell Biology, Department of Clinical Sciences in Malmö, Clinical research center, Lund University, Malmö, Sweden
| | - Nils Wierup
- Lund University Diabetes Centre, Neuroendocrine Cell Biology, Department of Clinical Sciences in Malmö, Clinical research center, Lund University, Malmö, Sweden
| | - Maria Björkqvist
- Wallenberg Neuroscience Center, Department of Experimental Medical Sciences, Brain Disease Biomarker Unit, Lund University, Lund, Sweden
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25
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Paré MF, Jasmin BJ. Chronic 5-Aminoimidazole-4-Carboxamide-1-β-d-Ribofuranoside Treatment Induces Phenotypic Changes in Skeletal Muscle, but Does Not Improve Disease Outcomes in the R6/2 Mouse Model of Huntington's Disease. Front Neurol 2017; 8:516. [PMID: 29021780 PMCID: PMC5623671 DOI: 10.3389/fneur.2017.00516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 09/14/2017] [Indexed: 12/29/2022] Open
Abstract
Huntington’s disease (HD) is an autosomal dominant neurodegenerative genetic disorder characterized by motor, cognitive, and psychiatric symptoms. It is well established that regular physical activity supports brain health, benefiting cognitive function, mental health as well as brain structure and plasticity. Exercise mimetics (EMs) are a group of drugs and small molecules that target signaling pathways in skeletal muscle known to be activated by endurance exercise. The EM 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) has been shown to induce cognitive benefits in healthy mice. Since AICAR does not readily cross the blood–brain barrier, its beneficial effect on the brain has been ascribed to its impact on skeletal muscle. Our objective, therefore, was to examine the effect of chronic AICAR treatment on the muscular and neurological pathology in a mouse model of HD. To this end, R6/2 mice were treated with AICAR for 8 weeks and underwent regular neurobehavioral testing. Under our conditions, AICAR increased expression of PGC-1α, a powerful phenotypic modifier of muscle, and induced the expected shift toward a more oxidative muscle phenotype in R6/2 mice. However, this treatment failed to induce benefits on HD progression. Indeed, neurobehavioral deficits, striatal, and muscle mutant huntingtin aggregate density, as well as muscle atrophy were not mitigated by the chronic administration of AICAR. Although the muscle adaptations seen in HD mice following AICAR treatment may still provide therapeutically relevant benefits to patients with limited mobility, our findings indicate that under our experimental conditions, AICAR had no effect on several hallmarks of HD.
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Affiliation(s)
- Marie-France Paré
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Bernard J Jasmin
- Faculty of Medicine, Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
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26
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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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27
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Park KH, Franciosi S, Parrant K, Lu G, Leavitt BR. p35 hemizygosity activates Akt but does not improve motor function in the YAC128 mouse model of Huntington’s disease. Neuroscience 2017; 352:79-87. [DOI: 10.1016/j.neuroscience.2017.03.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 01/25/2023]
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28
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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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29
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Glycolytic-to-oxidative fiber-type switch and mTOR signaling activation are early-onset features of SBMA muscle modified by high-fat diet. Acta Neuropathol 2016; 132:127-44. [PMID: 26971100 PMCID: PMC4911374 DOI: 10.1007/s00401-016-1550-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Revised: 02/19/2016] [Accepted: 02/19/2016] [Indexed: 12/13/2022]
Abstract
Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by the expansion of a polyglutamine tract in the androgen receptor (AR). The mechanism by which expansion of polyglutamine in AR causes muscle atrophy is unknown. Here, we investigated pathological pathways underlying muscle atrophy in SBMA knock-in mice and patients. We show that glycolytic muscles were more severely affected than oxidative muscles in SBMA knock-in mice. Muscle atrophy was associated with early-onset, progressive glycolytic-to-oxidative fiber-type switch. Whole genome microarray and untargeted lipidomic analyses revealed enhanced lipid metabolism and impaired glycolysis selectively in muscle. These metabolic changes occurred before denervation and were associated with a concurrent enhancement of mechanistic target of rapamycin (mTOR) signaling, which induced peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC1α) expression. At later stages of disease, we detected mitochondrial membrane depolarization, enhanced transcription factor EB (TFEB) expression and autophagy, and mTOR-induced protein synthesis. Several of these abnormalities were detected in the muscle of SBMA patients. Feeding knock-in mice a high-fat diet (HFD) restored mTOR activation, decreased the expression of PGC1α, TFEB, and genes involved in oxidative metabolism, reduced mitochondrial abnormalities, ameliorated muscle pathology, and extended survival. These findings show early-onset and intrinsic metabolic alterations in SBMA muscle and link lipid/glucose metabolism to pathogenesis. Moreover, our results highlight an HFD regime as a promising approach to support SBMA patients.
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30
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Veldman MB, Rios-Galdamez Y, Lu XH, Gu X, Qin W, Li S, Yang XW, Lin S. The N17 domain mitigates nuclear toxicity in a novel zebrafish Huntington's disease model. Mol Neurodegener 2015; 10:67. [PMID: 26645399 PMCID: PMC4673728 DOI: 10.1186/s13024-015-0063-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 11/30/2015] [Indexed: 01/14/2023] Open
Abstract
Background Although the genetic cause for Huntington’s disease (HD) has been known for over 20 years, the mechanisms that cause the neurotoxicity and behavioral symptoms of this disease are not well understood. One hypothesis is that N-terminal fragments of the HTT protein are the causative agents in HD and that peptide sequences adjacent to the poly-glutamine (Q) repeats modify its toxicity. Here we test the function of the N-terminal 17 amino acids (N17) in the context of the exon 1 fragment of HTT in a novel, inducible zebrafish model of HD. Results Deletion of N17 coupled with 97Q expansion (mHTT-ΔN17-exon1) resulted in a robust, rapidly progressing movement deficit, while fish with intact N17 and 97Q expansion (mHTT-exon1) have more delayed-onset movement deficits with slower progression. The level of mHTT-ΔN17-exon1 protein was significantly higher than mHTT-exon1, although the mRNA level of each transgene was marginally different, suggesting that N17 may regulate HTT protein stability in vivo. In addition, cell lineage specific induction of the mHTT-ΔN17-exon1 transgene in neurons was sufficient to recapitulate the consequences of ubiquitous transgene expression. Within neurons, accelerated nuclear accumulation of the toxic HTT fragment was observed in mHTT-ΔN17-exon1 fish, demonstrating that N17 also plays an important role in sub-cellular localization in vivo. Conclusions We have developed a novel, inducible zebrafish model of HD. These animals exhibit a progressive movement deficit reminiscent of that seen in other animal models and human patients. Deletion of the N17 terminal amino acids of the huntingtin fragment results in an accelerated HD-like phenotype that may be due to enhanced protein stability and nuclear accumulation of HTT. These transgenic lines will provide a valuable new tool to study mechanisms of HD at the behavioral, cellular, and molecular levels. Future experiments will be focused on identifying genetic modifiers, mechanisms and therapeutics that alleviate polyQ aggregation in the nucleus of neurons. Electronic supplementary material The online version of this article (doi:10.1186/s13024-015-0063-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matthew B Veldman
- Department of Molecular, Cell and Developmental Biology, University of California-Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Yesenia Rios-Galdamez
- Department of Molecular, Cell and Developmental Biology, University of California-Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA
| | - Xiao-Hong Lu
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, Los Angeles, USA.,Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, Los Angeles, USA.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Xiaofeng Gu
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, Los Angeles, USA.,Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, Los Angeles, USA.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Wei Qin
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Song Li
- Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - X William Yang
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, Los Angeles, USA.,Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, Los Angeles, USA.,Brain Research Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Shuo Lin
- Department of Molecular, Cell and Developmental Biology, University of California-Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA, 90095, USA. .,Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
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31
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Cubo E, Rivadeneyra J, Gil-Polo C, Armesto D, Mateos A, Mariscal-Pérez N. Body composition analysis as an indirect marker of skeletal muscle mass in Huntington's disease. J Neurol Sci 2015; 358:335-8. [DOI: 10.1016/j.jns.2015.09.351] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 09/08/2015] [Accepted: 09/14/2015] [Indexed: 10/23/2022]
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32
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Liu YJ, Chern Y. AMPK-mediated regulation of neuronal metabolism and function in brain diseases. J Neurogenet 2015; 29:50-8. [DOI: 10.3109/01677063.2015.1067203] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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33
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McMillan EM, Paré MF, Baechler BL, Graham DA, Rush JWE, Quadrilatero J. Autophagic signaling and proteolytic enzyme activity in cardiac and skeletal muscle of spontaneously hypertensive rats following chronic aerobic exercise. PLoS One 2015; 10:e0119382. [PMID: 25799101 PMCID: PMC4370727 DOI: 10.1371/journal.pone.0119382] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/30/2015] [Indexed: 11/19/2022] Open
Abstract
Hypertension is a cardiovascular disease associated with deleterious effects in skeletal and cardiac muscle. Autophagy is a degradative process essential to muscle health. Acute exercise can alter autophagic signaling. Therefore, we aimed to characterize the effects of chronic endurance exercise on autophagy in skeletal and cardiac muscle of normotensive and hypertensive rats. Male Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) were assigned to a sedentary condition or 6 weeks of treadmill running. White gastrocnemius (WG) of hypertensive rats had higher (p<0.05) caspase-3 and proteasome activity, as well as elevated calpain activity. In addition, skeletal muscle of hypertensive animals had elevated (p<0.05) ATG7 and LC3I protein, LAMP2 mRNA, and cathepsin activity, indicative of enhanced autophagic signaling. Interestingly, chronic exercise training increased (p<0.05) Beclin-1, LC3, and p62 mRNA as well as proteasome activity, but reduced (p<0.05) Beclin-1 and ATG7 protein, as well as decreased (p<0.05) caspase-3, calpain, and cathepsin activity. Left ventricle (LV) of hypertensive rats had reduced (p<0.05) AMPKα and LC3II protein, as well as elevated (p<0.05) p-AKT, p-p70S6K, LC3I and p62 protein, which collectively suggest reduced autophagic signaling. Exercise training had little effect on autophagy-related signaling factors in LV; however, exercise training increased (p<0.05) proteasome activity but reduced (p<0.05) caspase-3 and calpain activity. Our results suggest that autophagic signaling is altered in skeletal and cardiac muscle of hypertensive animals. Regular aerobic exercise can effectively alter the proteolytic environment in both cardiac and skeletal muscle, as well as influence several autophagy-related factors in skeletal muscle of normotensive and hypertensive rats.
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Affiliation(s)
- Elliott M. McMillan
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Marie-France Paré
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | | | - Drew A. Graham
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - James W. E. Rush
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
| | - Joe Quadrilatero
- Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada
- * E-mail:
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34
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Reinstating aberrant mTORC1 activity in Huntington's disease mice improves disease phenotypes. Neuron 2014; 85:303-15. [PMID: 25556834 DOI: 10.1016/j.neuron.2014.12.019] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2014] [Indexed: 12/28/2022]
Abstract
Huntington's disease (HD) is caused by a polyglutamine tract expansion in huntingtin (HTT). Despite HTTs ubiquitous expression, there is early and robust vulnerability in striatum, the cause of which is poorly understood. Here, we provide evidence that impaired striatal mTORC1 activity underlies varied metabolic and degenerative phenotypes in HD brain and show that introducing the constitutively active form of the mTORC1 regulator, Rheb, into HD mouse brain, alleviates mitochondrial dysfunction, aberrant cholesterol homeostasis, striatal atrophy, impaired dopamine signaling, and increases autophagy. We also find that the expression of Rhes, a striatum-enriched mTOR activator, is reduced in HD patient and mouse brain and that exogenous addition of Rhes alleviates motor deficits and improves brain pathology in HD mice. Our combined work indicates that impaired Rhes/mTORC1 activity in HD brain may underlie the notable striatal susceptibility and thus presents a promising therapeutic target for HD therapy.
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35
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Pryor WM, Biagioli M, Shahani N, Swarnkar S, Huang WC, Page DT, MacDonald ME, Subramaniam S. Huntingtin promotes mTORC1 signaling in the pathogenesis of Huntington's disease. Sci Signal 2014; 7:ra103. [DOI: 10.1126/scisignal.2005633] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Zielonka D, Piotrowska I, Marcinkowski JT, Mielcarek M. Skeletal muscle pathology in Huntington's disease. Front Physiol 2014; 5:380. [PMID: 25339908 PMCID: PMC4186279 DOI: 10.3389/fphys.2014.00380] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/13/2014] [Indexed: 12/13/2022] Open
Abstract
Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by the expansion of a polyglutamine stretch within the huntingtin protein (HTT). The neurological symptoms, that involve motor, cognitive and psychiatric disturbances, are caused by neurodegeneration that is particularly widespread in the basal ganglia and cereberal cortex. HTT is ubiquitously expressed and in recent years it has become apparent that HD patients experience a wide array of peripheral organ dysfunction including severe metabolic phenotype, weight loss, HD-related cardiomyopathy and skeletal muscle wasting. Although skeletal muscles pathology became a hallmark of HD, the mechanisms underlying muscular atrophy in this disorder are unknown. Skeletal muscles account for approximately 40% of body mass and are highly adaptive to physiological and pathological conditions that may result in muscle hypertrophy (due to increased mechanical load) or atrophy (inactivity, chronic disease states). The atrophy is caused by degeneration of myofibers and their replacement by fibrotic tissue is the major pathological feature in many genetic muscle disorders. Under normal physiological conditions the muscle function is orchestrated by a network of intrinsic hypertrophic and atrophic signals linked to the functional properties of the motor units that are likely to be imbalanced in HD. In this article, we highlight the emerging field of research with particular focus on the recent studies of the skeletal muscle pathology and the identification of new disease-modifying treatments.
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Affiliation(s)
- Daniel Zielonka
- Department of Social Medicine, Poznan University of Medical Sciences Poznan, Poland
| | | | - Jerzy T Marcinkowski
- Department of Social Medicine, Poznan University of Medical Sciences Poznan, Poland
| | - Michal Mielcarek
- Department of Medical and Molecular Genetics, King's College London London, UK
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Reduced motivation in the BACHD rat model of Huntington disease is dependent on the choice of food deprivation strategy. PLoS One 2014; 9:e105662. [PMID: 25144554 PMCID: PMC4140820 DOI: 10.1371/journal.pone.0105662] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Accepted: 07/25/2014] [Indexed: 11/30/2022] Open
Abstract
Huntington disease (HD) is an inherited neurodegenerative disease characterized by motor, cognitive, psychiatric and metabolic symptoms. Animal models of HD show phenotypes that can be divided into similar categories, with the metabolic phenotype of certain models being characterized by obesity. Although interesting in terms of modeling metabolic symptoms of HD, the obesity phenotype can be problematic as it might confound the results of certain behavioral tests. This concerns the assessment of cognitive function in particular, as tests for such phenotypes are often based on food depriving the animals and having them perform tasks for food rewards. The BACHD rat is a recently established animal model of HD, and in order to ensure that behavioral characterization of these rats is done in a reliable way, a basic understanding of their physiology is needed. Here, we show that BACHD rats are obese and suffer from discrete developmental deficits. When assessing the motivation to lever push for a food reward, BACHD rats were found to be less motivated than wild type rats, although this phenotype was dependent on the food deprivation strategy. Specifically, the phenotype was present when rats of both genotypes were deprived to 85% of their respective free-feeding body weight, but not when deprivation levels were adjusted in order to match the rats' apparent hunger levels. The study emphasizes the importance of considering metabolic abnormalities as a confounding factor when performing behavioral characterization of HD animal models.
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Kwartler CS, Chen J, Thakur D, Li S, Baskin K, Wang S, Wang ZV, Walker L, Hill JA, Epstein HF, Taegtmeyer H, Milewicz DM. Overexpression of smooth muscle myosin heavy chain leads to activation of the unfolded protein response and autophagic turnover of thick filament-associated proteins in vascular smooth muscle cells. J Biol Chem 2014; 289:14075-88. [PMID: 24711452 DOI: 10.1074/jbc.m113.499277] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Duplications spanning nine genes at the genomic locus 16p13.1 predispose individuals to acute aortic dissections. The most likely candidate gene in this region leading to the predisposition for dissection is MYH11, which encodes smooth muscle myosin heavy chain (SM-MHC). The effects of increased expression of MYH11 on smooth muscle cell (SMC) phenotypes were explored using mouse aortic SMCs with transgenic overexpression of one isoform of SM-MHC. We found that these cells show increased expression of Myh11 and myosin filament-associated contractile genes at the message level when compared with control SMCs, but not at the protein level due to increased protein degradation. Increased expression of Myh11 resulted in endoplasmic reticulum (ER) stress in SMCs, which led to a paradoxical decrease of protein levels through increased autophagic degradation. An additional consequence of ER stress in SMCs was increased intracellular calcium ion concentration, resulting in increased contractile signaling and contraction. The increased signals for contraction further promote transcription of contractile genes, leading to a feedback loop of metabolic abnormalities in these SMCs. We suggest that overexpression of MYH11 can lead to increased ER stress and autophagy, findings that may be globally implicated in disease processes associated with genomic duplications.
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Affiliation(s)
| | - Jiyuan Chen
- From the Departments of Internal Medicine and
| | - Dhananjay Thakur
- Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, Texas 77030
| | - Shumin Li
- the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555
| | | | | | - Zhao V Wang
- the Departments of Internal Medicine (Cardiology) and Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | - Lori Walker
- the Department of Medicine, University of Colorado, Denver, Colorado 80217
| | - Joseph A Hill
- the Departments of Internal Medicine (Cardiology) and Molecular Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and
| | - Henry F Epstein
- the Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555
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Dystropathology increases energy expenditure and protein turnover in the mdx mouse model of duchenne muscular dystrophy. PLoS One 2014; 9:e89277. [PMID: 24586653 PMCID: PMC3929705 DOI: 10.1371/journal.pone.0089277] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 01/17/2014] [Indexed: 11/19/2022] Open
Abstract
The skeletal muscles in Duchenne muscular dystrophy and the mdx mouse model lack functional dystrophin and undergo repeated bouts of necrosis, regeneration, and growth. These processes have a high metabolic cost. However, the consequences for whole body energy and protein metabolism, and on the dietary requirements for these macronutrients at different stages of the disease, are not well-understood. This study used juvenile (4- to 5- wk-old) and adult (12- to 14-wk-old) male dystrophic C57BL/10ScSn-mdx/J and age-matched C57BL/10ScSn/J control male mice to measure total and resting energy expenditure, food intake, spontaneous activity, body composition, whole body protein turnover, and muscle protein synthesis rates. In juvenile mdx mice that have extensive muscle damage, energy expenditure, muscle protein synthesis, and whole body protein turnover rates were higher than in age-matched controls. Adaptations in food intake and decreased activity were insufficient to meet the increased energy and protein needs of juvenile mdx mice and resulted in stunted growth. In (non-growing) adult mdx mice with less severe dystropathology, energy expenditure, muscle protein synthesis, and whole body protein turnover rates were also higher than in age-matched controls. Food intake was sufficient to meet their protein and energy needs, but insufficient to result in fat deposition. These data show that dystropathology impacts the protein and energy needs of mdx mice and that tailored dietary interventions are necessary to redress this imbalance. If not met, the resultant imbalance blunts growth, and may limit the benefits of therapies designed to protect and repair dystrophic muscles.
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Safren N, El Ayadi A, Chang L, Terrillion CE, Gould TD, Boehning DF, Monteiro MJ. Ubiquilin-1 overexpression increases the lifespan and delays accumulation of Huntingtin aggregates in the R6/2 mouse model of Huntington's disease. PLoS One 2014; 9:e87513. [PMID: 24475300 PMCID: PMC3903676 DOI: 10.1371/journal.pone.0087513] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 12/22/2013] [Indexed: 12/12/2022] Open
Abstract
Huntington's Disease (HD) is a neurodegenerative disorder that is caused by abnormal expansion of a polyglutamine tract in huntingtin (htt) protein. The expansion leads to increased htt aggregation and toxicity. Factors that aid in the clearance of mutant huntingtin proteins should relieve the toxicity. We previously demonstrated that overexpression of ubiqulin-1, which facilitates protein clearance through the proteasome and autophagy pathways, reduces huntingtin aggregates and toxicity in mammalian cell and invertebrate models of HD. Here we tested whether overexpression of ubiquilin-1 delays or prevents neurodegeneration in R6/2 mice, a well-established model of HD. We generated transgenic mice overexpressing human ubiquilin-1 driven by the neuron-specific Thy1.2 promoter. Immunoblotting and immunohistochemistry revealed robust and widespread overexpression of ubiquilin-1 in the brains of the transgenic mice. Similar analysis of R6/2 animals revealed that ubiquilin is localized in huntingtin aggregates and that ubiquilin levels decrease progressively to 30% during the end-stage of disease. We crossed our ubiquilin-1 transgenic line with R6/2 mice to assess whether restoration of ubiquilin levels would delay HD symptoms and pathology. In the double transgenic progeny, ubiquilin levels were fully restored, and this correlated with a 20% increase in lifespan and a reduction in htt inclusions in the hippocampus and cortex. Furthermore, immunoblots indicated that endoplasmic reticulum stress response that is elevated in the hippocampus of R6/2 animals was attenuated by ubiquilin-1 overexpression. However, ubiquilin-1 overexpression neither altered the load of htt aggregates in the striatum nor improved motor impairments in the mice.
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Affiliation(s)
- Nathaniel Safren
- Neuroscience Graduate Program, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- Center for Biomedical Engineering and Technology, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Amina El Ayadi
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Lydia Chang
- Center for Biomedical Engineering and Technology, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
| | - Chantelle E. Terrillion
- Neuroscience Graduate Program, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- Department of Psychiatry, School of Medicine University of Maryland, Baltimore, Maryland, United States of America
| | - Todd D. Gould
- Neuroscience Graduate Program, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- Department of Psychiatry, School of Medicine University of Maryland, Baltimore, Maryland, United States of America
- Department of Pharmacology, School of Medicine University of Maryland, Baltimore, Maryland, United States of America
| | - Darren F. Boehning
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Mervyn J. Monteiro
- Neuroscience Graduate Program, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- Center for Biomedical Engineering and Technology, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, Baltimore, Maryland, United States of America
- * E-mail:
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Johns N, Hatakeyama S, Stephens NA, Degen M, Degen S, Frieauff W, Lambert C, Ross JA, Roubenoff R, Glass DJ, Jacobi C, Fearon KCH. Clinical classification of cancer cachexia: phenotypic correlates in human skeletal muscle. PLoS One 2014; 9:e83618. [PMID: 24404136 PMCID: PMC3880262 DOI: 10.1371/journal.pone.0083618] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 11/05/2013] [Indexed: 12/18/2022] Open
Abstract
Background Cachexia affects the majority of patients with advanced cancer and is associated with a reduction in treatment tolerance, response to therapy, and duration of survival. One impediment towards the effective treatment of cachexia is a validated classification system. Methods 41 patients with resectable upper gastrointestinal (GI) or pancreatic cancer underwent characterisation for cachexia based on weight-loss (WL) and/or low muscularity (LM). Four diagnostic criteria were used >5%WL, >10%WL, LM, and LM+>2%WL. All patients underwent biopsy of the rectus muscle. Analysis included immunohistochemistry for fibre size and type, protein and nucleic acid concentration, Western blots for markers of autophagy, SMAD signalling, and inflammation. Findings Compared with non-cachectic cancer patients, patients with LM or LM+>2%WL, mean muscle fibre diameter was reduced by about 25% (p = 0.02 and p = 0.001 respectively). No significant difference in fibre diameter was observed if patients had WL alone. Regardless of classification, there was no difference in fibre number or proportion of fibre type across all myosin heavy chain isoforms. Mean muscle protein content was reduced and the ratio of RNA/DNA decreased in patients with either >5%WL or LM+>2%WL. Compared with non-cachectic patients, SMAD3 protein levels were increased in patients with >5%WL (p = 0.022) and with >10%WL, beclin (p = 0.05) and ATG5 (p = 0.01) protein levels were increased. There were no differences in phospho-NFkB or phospho-STAT3 levels across any of the groups. Conclusion Muscle fibre size, biochemical composition and pathway phenotype can vary according to whether the diagnostic criteria for cachexia are based on weight loss alone, a measure of low muscularity alone or a combination of the two. For intervention trials where the primary end-point is a change in muscle mass or function, use of combined diagnostic criteria may allow identification of a more homogeneous patient cohort, reduce the sample size required and enhance the time scale within which trials can be conducted.
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Affiliation(s)
- Neil Johns
- Department of Clinical and Surgical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Shinji Hatakeyama
- Novartis Institutes for BioMedical Research Basel, Novartis Pharma AG, Basel, Switzerland
| | - Nathan A. Stephens
- Department of Clinical and Surgical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Martin Degen
- Novartis Institutes for BioMedical Research Basel, Novartis Pharma AG, Basel, Switzerland
| | - Simone Degen
- Novartis Institutes for BioMedical Research Basel, Novartis Pharma AG, Basel, Switzerland
| | - Wilfried Frieauff
- Novartis Institutes for BioMedical Research Basel, Novartis Pharma AG, Basel, Switzerland
| | - Christian Lambert
- Novartis Institutes for BioMedical Research Basel, Novartis Pharma AG, Basel, Switzerland
| | - James A. Ross
- Department of Clinical and Surgical Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Ronenn Roubenoff
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - David J. Glass
- Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Carsten Jacobi
- Novartis Institutes for BioMedical Research Basel, Novartis Pharma AG, Basel, Switzerland
| | - Kenneth C. H. Fearon
- Department of Clinical and Surgical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Diamanti D, Mori E, Incarnato D, Malusa F, Fondelli C, Magnoni L, Pollio G. Whole gene expression profile in blood reveals multiple pathways deregulation in R6/2 mouse model. Biomark Res 2013; 1:28. [PMID: 24252798 PMCID: PMC4177605 DOI: 10.1186/2050-7771-1-28] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 10/15/2013] [Indexed: 01/04/2023] Open
Abstract
Background Huntington Disease (HD) is a progressive neurological disorder, with pathological manifestations in brain areas and in periphery caused by the ubiquitous expression of mutant Huntingtin protein. Transcriptional dysregulation is considered a key molecular mechanism responsible of HD pathogenesis but, although numerous studies investigated mRNA alterations in HD, so far none evaluated a whole gene expression profile in blood of R6/2 mouse model. Findings To discover novel pathogenic mechanisms and potential peripheral biomarkers useful to monitor disease progression or drug efficacy, a microarray study was performed in blood of R6/2 at manifest stage and wild type littermate mice. This approach allowed to propose new peripheral molecular processes involved in HD and to suggest different panels of candidate biomarkers. Among the discovered deregulated processes, we focused on specific ones: complement and coagulation cascades, PPAR signaling, cardiac muscle contraction, and dilated cardiomyopathy pathways. Selected genes derived from these pathways were additionally investigated in other accessible tissues to validate these matrices as source of biomarkers, and in brain, to link central and peripheral disease manifestations. Conclusions Our findings validated the skeletal muscle as suitable source to investigate peripheral transcriptional alterations in HD and supported the hypothesis that immunological alteration may contribute to neurological degeneration. Moreover, the identification of altered signaling in mouse blood enforce R6/2 transgenic mouse as a powerful HD model while suggesting novel disease biomarkers for pre-clinical investigation.
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Affiliation(s)
- Daniela Diamanti
- Siena Biotech S,p,A,, strada del Petriccio e Belriguardo, Siena 35, 53100, Italy.
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Ehrnhoefer DE, Skotte NH, Ladha S, Nguyen YTN, Qiu X, Deng Y, Huynh KT, Engemann S, Nielsen SM, Becanovic K, Leavitt BR, Hasholt L, Hayden MR. p53 increases caspase-6 expression and activation in muscle tissue expressing mutant huntingtin. Hum Mol Genet 2013; 23:717-29. [PMID: 24070868 DOI: 10.1093/hmg/ddt458] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Activation of caspase-6 in the striatum of both presymptomatic and affected persons with Huntington's disease (HD) is an early event in the disease pathogenesis. However, little is known about the role of caspase-6 outside the central nervous system (CNS) and whether caspase activation might play a role in the peripheral phenotypes, such as muscle wasting observed in HD. We assessed skeletal muscle tissue from HD patients and well-characterized mouse models of HD. Cleavage of the caspase-6 specific substrate lamin A is significantly increased in skeletal muscle obtained from HD patients as well as in muscle tissues from two different HD mouse models. p53, a transcriptional activator of caspase-6, is upregulated in neuronal cells and tissues expressing mutant huntingtin. Activation of p53 leads to a dramatic increase in levels of caspase-6 mRNA, caspase-6 activity and cleavage of lamin A. Using mouse embryonic fibroblasts (MEFs) from YAC128 mice, we show that this increase in caspase-6 activity can be mitigated by pifithrin-α (pifα), an inhibitor of p53 transcriptional activity, but not through the inhibition of p53's mitochondrial pro-apoptotic function. Remarkably, the p53-mediated increase in caspase-6 expression and activation is exacerbated in cells and tissues of both neuronal and peripheral origin expressing mutant huntingtin (Htt). These findings suggest that the presence of the mutant Htt protein enhances p53 activity and lowers the apoptotic threshold, which activates caspase-6. Furthermore, these results suggest that this pathway is activated both within and outside the CNS in HD and may contribute to both loss of CNS neurons and muscle atrophy.
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Affiliation(s)
- Dagmar E Ehrnhoefer
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, CFRI, University of British Columbia, 950 West 28th Avenue, Vancouver, BC V5Z 4H4, Canada
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Ayala-Peña S. Role of oxidative DNA damage in mitochondrial dysfunction and Huntington's disease pathogenesis. Free Radic Biol Med 2013; 62:102-110. [PMID: 23602907 PMCID: PMC3722255 DOI: 10.1016/j.freeradbiomed.2013.04.017] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 02/21/2013] [Accepted: 04/12/2013] [Indexed: 12/20/2022]
Abstract
Huntington's disease (HD) is a neurodegenerative disorder with an autosomal dominant expression pattern and typically a late-onset appearance. HD is a movement disorder with a heterogeneous phenotype characterized by involuntary dance-like gait, bioenergetic deficits, motor impairment, and cognitive and psychiatric deficits. Compelling evidence suggests that increased oxidative stress and mitochondrial dysfunction may underlie HD pathogenesis. However, the exact mechanisms underlying mutant huntingtin-induced neurological toxicity remain unclear. The objective of this paper is to review recent literature regarding the role of oxidative DNA damage in mitochondrial dysfunction and HD pathogenesis.
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Affiliation(s)
- Sylvette Ayala-Peña
- Department of Pharmacology and Toxicology, University of Puerto Rico Medical Sciences Campus, P.O. Box 365067, San Juan, Puerto Rico 00936-5067.
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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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Abstract
PURPOSE OF REVIEW There are a variety of pathophysiologic conditions that are known to induce skeletal muscle atrophy. However, muscle wasting can occur through multiple distinct signaling pathways with differential sensitivity between selective skeletal muscle fiber subtypes. This review summarizes some of the underlying molecular mechanisms responsible for fiber-specific muscle mass regulation. RECENT FINDINGS Peroxisome proliferator-activated receptor gamma coactivator 1-alpha protects slow-twitch oxidative fibers from denervation/immobilization (disuse)-induced muscle atrophies. Nutrient-related muscle atrophies, such as those induced by cancer cachexia, sepsis, chronic heart failure, or diabetes, are largely restricted to fast-twitch glycolytic fibers, of which the underlying mechanism is usually related to abnormality of protein degradation, including proteasomal and lysosomal pathways. In contrast, nuclear factor kappaB activation apparently serves a dual function by inducing both fast-twitch fiber atrophy and slow-twitch fiber degeneration. SUMMARY Fast-twitch glycolytic fibers are more vulnerable than slow-twitch oxidative fibers under a variety of atrophic conditions related to signaling transduction of Forkhead box O family, autophagy inhibition, transforming growth factor beta family, and nuclear factor-kappaB. The resistance of oxidative fibers may result from the protection of peroxisome proliferator-activated receptor gamma coactivator 1-alpha.
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Affiliation(s)
- Yichen Wang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Diabetes Research and Training Center, Bronx, New York, USA
| | - Jeffrey E. Pessin
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Diabetes Research and Training Center, Bronx, New York, USA
- Department of Medicine, Albert Einstein College of Medicine, Diabetes Research and Training Center, Bronx, New York, USA
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Basco D, Blaauw B, Pisani F, Sparaneo A, Nicchia GP, Mola MG, Reggiani C, Svelto M, Frigeri A. AQP4-dependent water transport plays a functional role in exercise-induced skeletal muscle adaptations. PLoS One 2013; 8:e58712. [PMID: 23520529 PMCID: PMC3592820 DOI: 10.1371/journal.pone.0058712] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 02/05/2013] [Indexed: 02/07/2023] Open
Abstract
In this study we assess the functional role of Aquaporin-4 (AQP4) in the skeletal muscle by analyzing whether physical activity modulates AQP4 expression and whether the absence of AQP4 has an effect on osmotic behavior, muscle contractile properties, and physical activity. To this purpose, rats and mice were trained on the treadmill for 10 (D10) and 30 (D30) days and tested with exercise to exhaustion, and muscles were used for immunoblotting, RT-PCR, and fiber-type distribution analysis. Taking advantage of the AQP4 KO murine model, functional analysis of AQP4 was performed on dissected muscle fibers and sarcolemma vesicles. Moreover, WT and AQP4 KO mice were subjected to both voluntary and forced activity. Rat fast-twitch muscles showed a twofold increase in AQP4 protein in D10 and D30 rats compared to sedentary rats. Such increase positively correlated with the animal performance, since highest level of AQP4 protein was found in high runner rats. Interestingly, no shift in muscle fiber composition nor an increase in AQP4-positive fibers was found. Furthermore, no changes in AQP4 mRNA after exercise were detected, suggesting that post-translational events are likely to be responsible for AQP4 modulation. Experiments performed on AQP4 KO mice revealed a strong impairment in osmotic responses as well as in forced and voluntary activities compared to WT mice, even though force development amplitude and contractile properties were unvaried. Our findings definitively demonstrate the physiological role of AQP4 in supporting muscle contractile activity and metabolic changes that occur in fast-twitch skeletal muscle during prolonged exercise.
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Affiliation(s)
- Davide Basco
- Department of Bioscience, Biotechnologies and Biopharmaceutics and Center of Excellence in Comparative Genomics (CEGBA), University of Bari, Bari, Italy
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Ju TC, Lin YS, Chern Y. Energy dysfunction in Huntington's disease: insights from PGC-1α, AMPK, and CKB. Cell Mol Life Sci 2012; 69:4107-20. [PMID: 22627493 PMCID: PMC11115139 DOI: 10.1007/s00018-012-1025-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Revised: 04/16/2012] [Accepted: 05/02/2012] [Indexed: 12/23/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disease caused by a CAG trinucleotide expansion in the Huntingtin (Htt) gene. When the number of CAG repeats exceeds 36, the translated polyglutamine-expanded Htt protein interferes with the normal functions of many types of cellular machinery and causes cytotoxicity. Clinical symptoms include progressive involuntary movement disorders, psychiatric signs, cognitive decline, dementia, and a shortened lifespan. The most severe brain atrophy is observed in the striatum and cortex. Besides the well-characterized neuronal defects, recent studies showed that the functions of mitochondria and several key players in energy homeostasis are abnormally regulated during HD progression. Energy dysregulation thus is now recognized as an important pathogenic pathway of HD. This review focuses on the importance of three key molecular determinants (peroxisome proliferator-activated receptor-γ coactivator-1α, AMP-activated protein kinase, and creatine kinase B) of cellular energy homeostasis and their possible involvement in HD pathogenesis.
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Affiliation(s)
- Tz-Chuen Ju
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei, 11529 Taiwan
| | - Yow-Sien Lin
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei, 11529 Taiwan
| | - Yijuang Chern
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Nankang, Taipei, 11529 Taiwan
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Figiel M, Szlachcic WJ, Switonski PM, Gabka A, Krzyzosiak WJ. Mouse models of polyglutamine diseases: review and data table. Part I. Mol Neurobiol 2012; 46:393-429. [PMID: 22956270 PMCID: PMC3461215 DOI: 10.1007/s12035-012-8315-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 07/29/2012] [Indexed: 12/23/2022]
Abstract
Polyglutamine (polyQ) disorders share many similarities, such as a common mutation type in unrelated human causative genes, neurological character, and certain aspects of pathogenesis, including morphological and physiological neuronal alterations. The similarities in pathogenesis have been confirmed by findings that some experimental in vivo therapy approaches are effective in multiple models of polyQ disorders. Additionally, mouse models of polyQ diseases are often highly similar between diseases with respect to behavior and the features of the disease. The common features shared by polyQ mouse models may facilitate the investigation of polyQ disorders and may help researchers explore the mechanisms of these diseases in a broader context. To provide this context and to promote the understanding of polyQ disorders, we have collected and analyzed research data about the characterization and treatment of mouse models of polyQ diseases and organized them into two complementary Excel data tables. The data table that is presented in this review (Part I) covers the behavioral, molecular, cellular, and anatomic characteristics of polyQ mice and contains the most current knowledge about polyQ mouse models. The structure of this data table is designed in such a way that it can be filtered to allow for the immediate retrieval of the data corresponding to a single mouse model or to compare the shared and unique aspects of many polyQ models. The second data table, which is presented in another publication (Part II), covers therapeutic research in mouse models by summarizing all of the therapeutic strategies employed in the treatment of polyQ disorders, phenotypes that are used to examine the effects of the therapy, and therapeutic outcomes.
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Affiliation(s)
- Maciej Figiel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland.
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