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Arciniegas Ruiz SM, Eldar-Finkelman H. Glycogen Synthase Kinase-3 Inhibitors: Preclinical and Clinical Focus on CNS-A Decade Onward. Front Mol Neurosci 2022; 14:792364. [PMID: 35126052 PMCID: PMC8813766 DOI: 10.3389/fnmol.2021.792364] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Accepted: 12/07/2021] [Indexed: 12/11/2022] Open
Abstract
The protein kinase, GSK-3, participates in diverse biological processes and is now recognized a promising drug discovery target in treating multiple pathological conditions. Over the last decade, a range of newly developed GSK-3 inhibitors of diverse chemotypes and inhibition modes has been developed. Even more conspicuous is the dramatic increase in the indications that were tested from mood and behavior disorders, autism and cognitive disabilities, to neurodegeneration, brain injury and pain. Indeed, clinical and pre-clinical studies were largely expanded uncovering new mechanisms and novel insights into the contribution of GSK-3 to neurodegeneration and central nerve system (CNS)-related disorders. In this review we summarize new developments in the field and describe the use of GSK-3 inhibitors in the variety of CNS disorders. This remarkable volume of information being generated undoubtedly reflects the great interest, as well as the intense hope, in developing potent and safe GSK-3 inhibitors in clinical practice.
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Tousley A, Iuliano M, Weisman E, Sapp E, Zhang N, Vodicka P, Alexander J, Aviolat H, Gatune L, Reeves P, Li X, Khvorova A, Ellerby LM, Aronin N, DiFiglia M, Kegel-Gleason KB. Rac1 Activity Is Modulated by Huntingtin and Dysregulated in Models of Huntington's Disease. J Huntingtons Dis 2020; 8:53-69. [PMID: 30594931 PMCID: PMC6398565 DOI: 10.3233/jhd-180311] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Background: Previous studies suggest that Huntingtin, the protein mutated in Huntington’s disease (HD), is required for actin based changes in cell morphology, and undergoes stimulus induced targeting to plasma membranes where it interacts with phospholipids involved in cell signaling. The small GTPase Rac1 is a downstream target of growth factor stimulation and PI 3-kinase activity and is critical for actin dependent membrane remodeling. Objective: To determine if Rac1 activity is impaired in HD or regulated by normal Huntingtin. Methods: Analyses were performed in differentiated control and HD human stem cells and HD Q140/Q140 knock-in mice. Biochemical methods included SDS-PAGE, western blot, immunoprecipitation, affinity chromatography, and ELISA based Rac activity assays. Results: Basal Rac1 activity increased following depletion of Huntingtin with Huntingtin specific siRNA in human primary fibroblasts and in human control neuron cultures. Human cells (fibroblasts, neural stem cells, and neurons) with the HD mutation failed to increase Rac1 activity in response to growth factors. Rac1 activity levels were elevated in striatum of 1.5-month-old HD Q140/Q140 mice and in primary embryonic cortical neurons from HD mice. Affinity chromatography analysis of striatal lysates showed that Huntingtin is in a complex with Rac1, p85α subunit of PI 3-kinase, and the actin bundling protein α-actinin and interacts preferentially with the GTP bound form of Rac1. The HD mutation reduced Huntingtin interaction with p85α. Conclusions: These findings suggest that Huntingtin regulates Rac1 activity as part of a coordinated response to growth factor signaling and this function is impaired early in HD.
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Affiliation(s)
- Adelaide Tousley
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Maria Iuliano
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Elizabeth Weisman
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Ellen Sapp
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Ningzhe Zhang
- Buck Institute for Research on Aging, Novato, CA, USA
| | - Petr Vodicka
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Jonathan Alexander
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Hubert Aviolat
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Leah Gatune
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Patrick Reeves
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Xueyi Li
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Anastasia Khvorova
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | | | - Neil Aronin
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, USA.,Department of Medicine and Cell Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Marian DiFiglia
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Kimberly B Kegel-Gleason
- Department of Neurology, Laboratory of Cellular Neurobiology, Massachusetts General Hospital, Charlestown, MA, USA
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Valvassori SS, Dal-Pont GC, Resende WR, Jornada LK, Peterle BR, Machado AG, Farias HR, de Souza CT, Carvalho AF, Quevedo J. Lithium and valproate act on the GSK-3β signaling pathway to reverse manic-like behavior in an animal model of mania induced by ouabain. Neuropharmacology 2017; 117:447-459. [DOI: 10.1016/j.neuropharm.2016.10.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 10/04/2016] [Accepted: 10/13/2016] [Indexed: 11/28/2022]
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Abstract
Redox homeostasis is crucial for proper cellular functions, including receptor tyrosine kinase signaling, protein folding, and xenobiotic detoxification. Under basal conditions, there is a balance between oxidants and antioxidants. This balance facilitates the ability of oxidants, such as reactive oxygen species, to play critical regulatory functions through a direct modification of a small number of amino acids (e.g. cysteine) on signaling proteins. These signaling functions leverage tight spatial, amplitude, and temporal control of oxidant concentrations. However, when oxidants overwhelm the antioxidant capacity, they lead to a harmful condition of oxidative stress. Oxidative stress has long been held to be one of the key players in disease progression for Huntington's disease (HD). In this review, we will critically review this evidence, drawing some intermediate conclusions, and ultimately provide a framework for thinking about the role of oxidative stress in the pathophysiology of HD.
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Affiliation(s)
- Amit Kumar
- Burke Medical Research Institute, White Plains, NY, USA
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA
- Department of Neurology, Weill Medical College of Cornell University, New York, NY, USA
| | - Rajiv R. Ratan
- Burke Medical Research Institute, White Plains, NY, USA
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA
- Department of Neurology, Weill Medical College of Cornell University, New York, NY, USA
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Vodicka P, Mo S, Tousley A, Green KM, Sapp E, Iuliano M, Sadri-Vakili G, Shaffer SA, Aronin N, DiFiglia M, Kegel-Gleason KB. Mass Spectrometry Analysis of Wild-Type and Knock-in Q140/Q140 Huntington's Disease Mouse Brains Reveals Changes in Glycerophospholipids Including Alterations in Phosphatidic Acid and Lyso-Phosphatidic Acid. J Huntingtons Dis 2016; 4:187-201. [PMID: 26397899 DOI: 10.3233/jhd-150149] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Huntington's disease (HD) is a neurodegenerative disease caused by a CAG expansion in the HD gene, which encodes the protein Huntingtin. Huntingtin associates with membranes and can interact directly with glycerophospholipids in membranes. OBJECTIVE We analyzed glycerophospholipid profiles from brains of 11 month old wild-type (WT) and Q140/Q140 HD knock-in mice to assess potential changes in glycerophospholipid metabolism. METHODS Polar lipids from cerebellum, cortex, and striatum were extracted and analyzed by liquid chromatography and negative ion electrospray tandem mass spectrometry analysis (LC-MS/MS). Gene products involved in polar lipid metabolism were studied using western blotting, immuno-electron microscopy and qPCR. RESULTS Significant changes in numerous species of glycerophosphate (phosphatidic acid, PA) were found in striatum, cerebellum and cortex from Q140/Q140 HD mice compared to WT mice at 11 months. Changes in specific species could also be detected for other glycerophospholipids. Increases in species of lyso-PA (LPA) were measured in striatum of Q140/Q140 HD mice compared to WT. Protein levels for c-terminal binding protein 1 (CtBP1), a regulator of PA biosynthesis, were reduced in striatal synaptosomes from HD mice compared to wild-type at 6 and 12 months. Immunoreactivity for CtBP1 was detected on membranes of synaptic vesicles in striatal axon terminals in the globus pallidus. CONCLUSIONS These novel results identify a potential site of molecular pathology caused by mutant Huntingtin that may impart early changes in HD.
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Affiliation(s)
- Petr Vodicka
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Shunyan Mo
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Adelaide Tousley
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Karin M Green
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Maria Iuliano
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | | | - Scott A Shaffer
- Proteomics and Mass Spectrometry Facility and Department of Biochemistry and Molecular Pharmacology, UMASS Medical School, Worcester, MA, USA
| | - Neil Aronin
- Departments of Medicine and Cell and Developmental Biology, UMASS Medical School, Worcester, MA, USA
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
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GSK-3β-induced Tau pathology drives hippocampal neuronal cell death in Huntington's disease: involvement of astrocyte-neuron interactions. Cell Death Dis 2016; 7:e2206. [PMID: 27124580 PMCID: PMC4855649 DOI: 10.1038/cddis.2016.104] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/11/2016] [Accepted: 03/15/2016] [Indexed: 02/06/2023]
Abstract
Glycogen synthase kinase-3β (GSK-3β) has emerged as a critical factor in several pathways involved in hippocampal neuronal maintenance and function. In Huntington's disease (HD), there are early hippocampal deficits both in patients and transgenic mouse models, which prompted us to investigate whether disease-specific changes in GSK-3β expression may underlie these abnormalities. Thirty-three postmortem hippocampal samples from HD patients (neuropathological grades 2-4) and age- and sex-matched normal control cases were analyzed using real-time quantitative reverse transcription PCRs (qPCRs) and immunohistochemistry. In vitro and in vivo studies looking at hippocampal pathology and GSK-3β were also undertaken in transgenic R6/2 and wild-type mice. We identified a disease and stage-dependent upregulation of GSK-3β mRNA and protein levels in the HD hippocampus, with the active isoform pGSK-3β-Tyr(216) being strongly expressed in dentate gyrus (DG) neurons and astrocytes at a time when phosphorylation of Tau at the AT8 epitope was also present in these same neurons. This upregulation of pGSK-3β-Tyr(216) was also found in the R6/2 hippocampus in vivo and linked to the increased vulnerability of primary hippocampal neurons in vitro. In addition, the increased expression of GSK-3β in the astrocytes of R6/2 mice appeared to be the main driver of Tau phosphorylation and caspase3 activation-induced neuronal death, at least in part via an exacerbated production of major proinflammatory mediators. This stage-dependent overactivation of GSK-3β in HD-affected hippocampal neurons and astrocytes therefore points to GSK-3β as being a critical factor in the pathological development of this condition. As such, therapeutic targeting of this pathway may help ameliorate neuronal dysfunction in HD.
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Lewis EA, Smith GA. Using Drosophila models of Huntington's disease as a translatable tool. J Neurosci Methods 2015; 265:89-98. [PMID: 26241927 DOI: 10.1016/j.jneumeth.2015.07.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 07/10/2015] [Accepted: 07/13/2015] [Indexed: 11/17/2022]
Abstract
The Huntingtin (Htt) protein is essential for a wealth of intracellular signaling cascades and when mutated, causes multifactorial dysregulation of basic cellular processes. Understanding the contribution to each of these intracellular pathways is essential for the elucidation of mechanisms that drive pathophysiology. Using appropriate models of Huntington's disease (HD) is key to finding the molecular mechanisms that contribute to neurodegeneration. While mouse models and cell lines expressing mutant Htt have been instrumental to HD research, there has been a significant contribution to our understating of the disease from studies utilizing Drosophila melanogaster. Flies have an Htt protein, so the endogenous pathways with which it interacts are likely conserved. Transgenic flies engineered to overexpress the human mutant HTT gene display protein aggregation, neurodegeneration, behavioral deficits and a reduced lifespan. The short life span of flies, low cost of maintaining stocks and genetic tools available for in vivo manipulation make them ideal for the discovery of new genes that are involved in HD pathology. It is possible to do rapid genome wide screens for enhancers or suppressors of the mutant Htt-mediated phenotype, expressed in specific tissues or neuronal subtypes. However, there likely remain many yet unknown genes that modify disease progression, which could be found through additional screening approaches using the fly. Importantly, there have been instances where genes discovered in Drosophila have been translated to HD mouse models.
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Affiliation(s)
- Elizabeth A Lewis
- Neurobiology Department, Aaron Lazare Research Building, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Gaynor A Smith
- Neurobiology Department, Aaron Lazare Research Building, University of Massachusetts Medical School, Worcester, MA 01605, USA.
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Valencia A, Sapp E, Kimm JS, McClory H, Ansong KA, Yohrling G, Kwak S, Kegel KB, Green KM, Shaffer SA, Aronin N, DiFiglia M. Striatal synaptosomes from Hdh140Q/140Q knock-in mice have altered protein levels, novel sites of methionine oxidation, and excess glutamate release after stimulation. J Huntingtons Dis 2014; 2:459-75. [PMID: 24696705 DOI: 10.3233/jhd-130080] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Synaptic connections are disrupted in patients with Huntington's disease (HD). Synaptosomes from postmortem brain are ideal for synaptic function studies because they are enriched in pre- and post-synaptic proteins important in vesicle fusion, vesicle release, and neurotransmitter receptor activation. OBJECTIVE To examine striatal synaptosomes from 3, 6 and 12 month old WT and Hdh140Q/140Q knock-in mice for levels of synaptic proteins, methionine oxidation, and glutamate release. METHODS We used Western blot analysis, glutamate release assays, and liquid chromatography tandem mass spectrometry (LC-MS/MS). RESULTS Striatal synaptosomes of 6 month old Hdh140Q/140Q mice had less DARPP32, syntaxin 1 and calmodulin compared to WT. Striatal synaptosomes of 12 month old Hdh140Q/140Q mice had lower levels of DARPP32, alpha actinin, HAP40, Na+/K+-ATPase, PSD95, SNAP-25, TrkA and VAMP1, VGlut1 and VGlut2, increased levels of VAMP2, and modifications in actin and calmodulin compared to WT. More glutamate released from vesicles of depolarized striatal synaptosomes of 6 month old Hdh140Q/140Q than from age matched WT mice but there was no difference in glutamate release in synaptosomes of 3 and 12 month old WT and Hdh140Q/140Q mice. LC-MS/MS of 6 month old Hdh140Q/140Q mice striatal synaptosomes revealed that about 4% of total proteins detected (>600 detected) had novel sites of methionine oxidation including proteins involved with vesicle fusion, trafficking, and neurotransmitter function (synaptophysin, synapsin 2, syntaxin 1, calmodulin, cytoplasmic actin 2, neurofilament, and tubulin). Altered protein levels and novel methionine oxidations were also seen in cortical synaptosomes of 12 month old Hdh140Q/140Q mice. CONCLUSIONS Findings provide support for early synaptic dysfunction in Hdh140Q/140Q knock-in mice arising from altered protein levels, oxidative damage, and impaired glutamate neurotransmission and suggest that study of synaptosomes could be of value for evaluating HD therapies.
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Dysregulation of system xc(-) expression induced by mutant huntingtin in a striatal neuronal cell line and in R6/2 mice. Neurochem Int 2014; 76:59-69. [PMID: 25004085 DOI: 10.1016/j.neuint.2014.06.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 06/25/2014] [Accepted: 06/30/2014] [Indexed: 01/18/2023]
Abstract
Oxidative stress has been implicated in the pathogenesis of Huntington's disease (HD), however, the origin of the oxidative stress is unknown. System xc(-) plays a role in the import of cystine to synthesize the antioxidant glutathione. We found in the STHdh(Q7/Q7) and STHdh(Q111/Q111) striatal cell lines, derived from neuronal precursor cells isolated from knock-in mice containing 7 or 111 CAG repeats in the huntingtin gene, that there is a decrease in system xc(-) function. System xc(-) is composed of two proteins, the substrate specific transporter, xCT, and an anchoring protein, CD98. The decrease in function in system xc(-) that we observed is caused by a decrease in xCT mRNA and protein expression in the STHdh(Q111/Q111) cells. In addition, we found a decrease in protein and mRNA expression in the transgenic R6/2 HD mouse model at 6weeks of age. STHdh(Q111/Q111) cells have lower basal levels of GSH and higher basal levels of ROS. Acute inhibition of system xc(-) causes greater increase in oxidative stress in the STHdh(Q111/Q111) cells than in the STHdh(Q7/Q7) cells. These results suggest that a defect in the regulation of xCT may be involved in the pathogenesis of HD by compromising xCT expression and increasing susceptibility to oxidative stress.
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Disassociation of histone deacetylase-3 from normal huntingtin underlies mutant huntingtin neurotoxicity. J Neurosci 2013; 33:11833-8. [PMID: 23864673 DOI: 10.1523/jneurosci.5831-12.2013] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Huntington's disease (HD) is caused by a polyglutamine expansion within the huntingtin (Htt) protein. Both loss of function of normal Htt and gain of a toxic function by the polyglutamine-expanded mutant Htt protein have been proposed to be responsible for HD, although the molecular mechanisms involved are unclear. We show that Htt is a neuroprotective protein in both HD-related and unrelated model systems. Neuroprotection by Htt is mediated by its sequestration of histone deacetylase-3 (HDAC3), a protein known to promote neuronal death. In contrast to the normal Htt, mutant Htt interacts poorly with HDAC3. However, expression of mutant Htt liberates HDAC3 from Htt, thus de-repressing its neurotoxic activity. Indeed, mutant Htt neurotoxicity is inhibited by the knockdown of HDAC3 and markedly reduced in HDAC3-deficient neurons. A reduction in Htt-HDAC3 interaction is also seen in neurons exposed to other apoptotic stimuli and in the striatum of R6/2 HD mice. Our results suggest that the robust interaction between Htt and HDAC3 along with the ability of mutant Htt to disrupt this association while not itself interacting with HDAC3 provides an explanation for both the loss-of-function and gain-of-toxic-function mechanisms proposed for HD. Moreover, our results identify HDAC3 as an essential player in mutant Htt-induced neurodegeneration.
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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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Valencia A, Sapp E, Kimm JS, McClory H, Reeves PB, Alexander J, Ansong KA, Masso N, Frosch MP, Kegel KB, Li X, DiFiglia M. Elevated NADPH oxidase activity contributes to oxidative stress and cell death in Huntington's disease. Hum Mol Genet 2012; 22:1112-31. [PMID: 23223017 DOI: 10.1093/hmg/dds516] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
A mutation in the huntingtin (Htt) gene produces mutant Htt and Huntington's disease (HD), a neurodegenerative disorder. HD patients have oxidative damage in the brain, but the causes are unclear. Compared with controls, we found brain levels of NADPH oxidase (NOX) activity, which produces reactive oxygen species (ROS), elevated in human HD postmortem cortex and striatum and highest in striatum of presymptomatic individuals. Synaptosome fractions from cortex and striatum of HD(140Q/140Q) mice had elevated NOX activity at 3 months of age and a further rise at 6 and 12 months compared with synaptosomes of age-matched wild-type (WT) mice. High NOX activity in primary cortical and striatal neurons of HD(140Q/140Q) mice correlated with more ROS and neurite swellings. These features and neuronal cell death were markedly reduced by treatment with NOX inhibitors such as diphenyleneiodonium (DPI), apocynin (APO) and VAS2870. The rise in ROS levels in mitochondria of HD(140Q/140Q) neurons followed the rise in NOX activity and inhibiting only mitochondrial ROS was not neuroprotective. Mutant Htt colocalized at plasma membrane lipid rafts with gp91-phox, a catalytic subunit for the NOX2 isoform. Assembly of NOX2 components at lipid rafts requires activation of Rac1 which was also elevated in HD(140Q/140Q) neurons. HD(140Q/140Q) mice bred to gp91-phox knock-out mice had lower NOX activity in the brain and in primary neurons, and neurons had normal ROS levels and significantly improved survival. These findings suggest that increased NOX2 activity at lipid rafts is an early and major source of oxidative stress and cell death in HD(140Q/140Q) neurons.
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Affiliation(s)
- Antonio Valencia
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, 114 16th Street, Charlestown, MA 02129, USA
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Ritch JJ, Valencia A, Alexander J, Sapp E, Gatune L, Sangrey GR, Sinha S, Scherber CM, Zeitlin S, Sadri-Vakili G, Irimia D, Difiglia M, Kegel KB. Multiple phenotypes in Huntington disease mouse neural stem cells. Mol Cell Neurosci 2012; 50:70-81. [PMID: 22508027 DOI: 10.1016/j.mcn.2012.03.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Revised: 03/09/2012] [Accepted: 03/29/2012] [Indexed: 11/25/2022] Open
Abstract
Neural stem (NS) cells are a limitless resource, and thus superior to primary neurons for drug discovery provided they exhibit appropriate disease phenotypes. Here we established NS cells for cellular studies of Huntington's disease (HD). HD is a heritable neurodegenerative disease caused by a mutation resulting in an increased number of glutamines (Q) within a polyglutamine tract in Huntingtin (Htt). NS cells were isolated from embryonic wild-type (Htt(7Q/7Q)) and "knock-in" HD (Htt(140Q/140Q)) mice expressing full-length endogenous normal or mutant Htt. NS cells were also developed from mouse embryonic stem cells that were devoid of Htt (Htt(-/-)), or knock-in cells containing human exon1 with an N-terminal FLAG epitope tag and with 7Q or 140Q inserted into one of the mouse alleles (Htt(F7Q/7Q) and Htt(F140Q/7Q)). Compared to Htt(7Q/7Q) NS cells, HD Htt(140Q/140Q) NS cells showed significantly reduced levels of cholesterol, increased levels of reactive oxygen species (ROS), and impaired motility. The heterozygous Htt(F140Q/7Q) NS cells had increased ROS and decreased motility compared to Htt(F7Q/7Q). These phenotypes of HD NS cells replicate those seen in HD patients or in primary cell or in vivo models of HD. Huntingtin "knock-out" NS cells (Htt(-/-)) also had impaired motility, but in contrast to HD cells had increased cholesterol. In addition, Htt(140Q/140Q) NS cells had higher phospho-AKT/AKT ratios than Htt(7Q/7Q) NS cells in resting conditions and after BDNF stimulation, suggesting mutant htt affects AKT dependent growth factor signaling. Upon differentiation, the Htt(7Q/7Q) and Htt(140Q/140Q) generated numerous Beta(III)-Tubulin- and GABA-positive neurons; however, after 15 days the cellular architecture of the differentiated Htt(140Q/140Q) cultures changed compared to Htt(7Q/7Q) cultures and included a marked increase of GFAP-positive cells. Our findings suggest that NS cells expressing endogenous mutant Htt will be useful for study of mechanisms of HD and drug discovery.
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Affiliation(s)
- James J Ritch
- MassGeneral Institute for Neurodegenerative Disease, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, United States
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