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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: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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Tousley A, Iuliano M, Weisman E, Sapp E, Richardson H, Vodicka P, Alexander J, Aronin N, DiFiglia M, Kegel-Gleason KB. Huntingtin associates with the actin cytoskeleton and α-actinin isoforms to influence stimulus dependent morphology changes. PLoS One 2019; 14:e0212337. [PMID: 30768638 PMCID: PMC6377189 DOI: 10.1371/journal.pone.0212337] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 01/31/2019] [Indexed: 01/09/2023] Open
Abstract
One response of cells to growth factor stimulus involves changes in morphology driven by the actin cytoskeleton and actin associated proteins which regulate functions such as cell adhesion, motility and in neurons, synaptic plasticity. Previous studies suggest that Huntingtin may be involved in regulating morphology however, there has been limited evidence linking endogenous Huntingtin localization or function with cytoplasmic actin in cells. We found that depletion of Huntingtin in human fibroblasts reduced adhesion and altered morphology and these phenotypes were made worse with growth factor stimulation, whereas the presence of the Huntington's Disease mutation inhibited growth factor induced changes in morphology and increased numbers of vinculin-positive focal adhesions. Huntingtin immunoreactivity localized to actin stress fibers, vinculin-positive adhesion contacts and membrane ruffles in fibroblasts. Interactome data from others has shown that Huntingtin can associate with α-actinin isoforms which bind actin filaments. Mapping studies using a cDNA encoding α-actinin-2 showed that it interacts within Huntingtin aa 399-969. Double-label immunofluorescence showed Huntingtin and α-actinin-1 co-localized to stress fibers, membrane ruffles and lamellar protrusions in fibroblasts. Proximity ligation assays confirmed a close molecular interaction between Huntingtin and α-actinin-1 in human fibroblasts and neurons. Huntingtin silencing with siRNA in fibroblasts blocked the recruitment of α-actinin-1 to membrane foci. These studies support the idea that Huntingtin is involved in regulating adhesion and actin dependent functions including those involving α-actinin.
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Affiliation(s)
- Adelaide Tousley
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Maria Iuliano
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Elizabeth Weisman
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Ellen Sapp
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Heather Richardson
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Petr Vodicka
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Jonathan Alexander
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Neil Aronin
- Department of Medicine and Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Marian DiFiglia
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Kimberly B. Kegel-Gleason
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- * E-mail:
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Vodicka P, Chase K, Iuliano M, Tousley A, Valentine DT, Sapp E, Kegel-Gleason KB, Sena-Esteves M, Aronin N, DiFiglia M. Autophagy Activation by Transcription Factor EB (TFEB) in Striatum of HDQ175/Q7 Mice. J Huntingtons Dis 2017; 5:249-260. [PMID: 27689619 PMCID: PMC5088406 DOI: 10.3233/jhd-160211] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Background: Mutant huntingtin (mHTT) is encoded by the Huntington’s disease (HD) gene and its accumulation in the brain contributes to HD pathogenesis. Reducing mHTT levels through activation of the autophagosome-lysosomal pathway may have therapeutic benefit. Transcription factor EB (TFEB) regulates lysosome biogenesis and autophagy. Objective: To examine if increasing TFEB protein levels in HD mouse striatum induces autophagy and influences mHTT levels. Methods: We introduced cDNA encoding TFEB with an HA tag (TFEB-HA) under the control of neuron specific synapsin 1 promoter into the striatum of 3 month old HDQ175/Q7 mice using adeno-associated virus AAV2/9. The levels of exogenous TFEB were analyzed using qPCR and Western blot. Proteins involved in autophagy, levels of huntingtin, and striatal-enriched proteins were examined using biochemical and/or immunohistochemical methods. Results: In HD mice expressing TFEB-HA, HA immunoreactivity distributed throughout the striatum in neuronal cell bodies and processes and preferentially in neuronal nuclei and overlapped with a loss of DARPP32 immunoreactivity. TFEB-HA mRNA and protein were detected in striatal lysates. There were increased levels of proteins involved with autophagosome/lysosome activity including LAMP-2A, LC3II, and cathepsin D and reduced levels of mutant HTT and the striatal enriched proteins DARPP32 and PDE10A. Compared to WT mice, HDQ175/Q7 mice had elevated levels of the ER stress protein GRP78/BiP and with TFEB-HA expression, increased levels of the astrocyte marker GFAP and pro-caspase 3. Conclusion: These results suggest that TFEB expression in the striatum of HDQ175/Q7 mice stimulates autophagy and lysosome activity, and lowers mHTT, but may also increase a neuronal stress response.
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Affiliation(s)
- Petr Vodicka
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Kathryn Chase
- Departments of Medicine and Cell Biology, University of Massachusetts, Worcester, MA, USA
| | - Maria Iuliano
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Adelaide Tousley
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Dana T Valentine
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Ellen Sapp
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Kimberly B Kegel-Gleason
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Miguel Sena-Esteves
- Department of Neurology, Horae Gene Therapy Center, University of Massachusetts Medical School, Albert Sherman Center, Worcester, MA, USA
| | - Neil Aronin
- Departments of Medicine and Cell Biology, University of Massachusetts, Worcester, MA, USA
| | - Marian DiFiglia
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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Abstract
Induced pluripotent stem cells (iPSCs) derived from controls and patients can act as a starting point for in vitro differentiation into human brain cells for discovery of novel targets and treatments for human disease without the same ethical limitations posed by embryonic stem cells. Numerous groups have successfully produced and characterized Huntington’s disease (HD) iPSCs with different CAG repeat lengths, including cells from patients with one or two HD alleles. HD iPSCs and the neural cell types derived from them recapitulate some disease phenotypes found in both human patients and animal models. Although these discoveries are encouraging, the use of iPSCs for cutting edge and reproducible research has been limited due to some of the inherent problems with cell lines and the technological differences in the way laboratories use them. The goal of this review is to summarize the current state of the HD iPSC field, and to highlight some of the issues that need to be addressed to maximize their potential as research tools.
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Affiliation(s)
| | - Kimberly B. Kegel-Gleason
- Correspondence to: Kimberly Kegel-Gleason, Assistant Professor in Neurology, Massachusetts General Hospital and Harvard Medical School, 114 16th Street, Room 2001, Charlestown, MA 02129, USA. Tel.: +1 617 724 8754; E-mail:
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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