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Godfrey RK, Alsop E, Bjork RT, Chauhan BS, Ruvalcaba HC, Antone J, Gittings LM, Michael AF, Williams C, Hala'ufia G, Blythe AD, Hall M, Sattler R, Van Keuren-Jensen K, Zarnescu DC. Modelling TDP-43 proteinopathy in Drosophila uncovers shared and neuron-specific targets across ALS and FTD relevant circuits. Acta Neuropathol Commun 2023; 11:168. [PMID: 37864255 PMCID: PMC10588218 DOI: 10.1186/s40478-023-01656-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 09/19/2023] [Indexed: 10/22/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) comprise a spectrum of neurodegenerative diseases linked to TDP-43 proteinopathy, which at the cellular level, is characterized by loss of nuclear TDP-43 and accumulation of cytoplasmic TDP-43 inclusions that ultimately cause RNA processing defects including dysregulation of splicing, mRNA transport and translation. Complementing our previous work in motor neurons, here we report a novel model of TDP-43 proteinopathy based on overexpression of TDP-43 in a subset of Drosophila Kenyon cells of the mushroom body (MB), a circuit with structural characteristics reminiscent of vertebrate cortical networks. This model recapitulates several aspects of dementia-relevant pathological features including age-dependent neuronal loss, nuclear depletion and cytoplasmic accumulation of TDP-43, and behavioral deficits in working memory and sleep that occur prior to axonal degeneration. RNA immunoprecipitations identify several candidate mRNA targets of TDP-43 in MBs, some of which are unique to the MB circuit and others that are shared with motor neurons. Among the latter is the glypican Dally-like-protein (Dlp), which exhibits significant TDP-43 associated reduction in expression during aging. Using genetic interactions we show that overexpression of Dlp in MBs mitigates TDP-43 dependent working memory deficits, conistent with Dlp acting as a mediator of TDP-43 toxicity. Substantiating our findings in the fly model, we find that the expression of GPC6 mRNA, a human ortholog of dlp, is specifically altered in neurons exhibiting the molecular signature of TDP-43 pathology in FTD patient brains. These findings suggest that circuit-specific Drosophila models provide a platform for uncovering shared or disease-specific molecular mechanisms and vulnerabilities across the spectrum of TDP-43 proteinopathies.
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Affiliation(s)
- R Keating Godfrey
- Department of Molecular and Cellular Biology, Life Sciences South, University of Arizona, 1007 E. Lowell St., Tucson, AZ, 85721, USA.
- McGuire Center for Lepidoptera and Biodiversity, Florida Museum of Natural History, University of Florida, 3215 Hull Road, Gainesville, FL, 32611, USA.
| | - Eric Alsop
- Translational Genomics Research Institute, 445 N 5th St., Phoenix, AZ, 85004, USA
| | - Reed T Bjork
- Department of Molecular and Cellular Biology, Life Sciences South, University of Arizona, 1007 E. Lowell St., Tucson, AZ, 85721, USA
| | - Brijesh S Chauhan
- Cellular and Molecular Physiology, Penn State College of Medicine, 500 University Drive Crescent Building C4605, Hershey, PA, 17033, USA
| | - Hillary C Ruvalcaba
- Department of Molecular and Cellular Biology, Life Sciences South, University of Arizona, 1007 E. Lowell St., Tucson, AZ, 85721, USA
| | - Jerry Antone
- Translational Genomics Research Institute, 445 N 5th St., Phoenix, AZ, 85004, USA
| | - Lauren M Gittings
- Department of Translational Neuroscience, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ, 85013, USA
| | - Allison F Michael
- Department of Molecular and Cellular Biology, Life Sciences South, University of Arizona, 1007 E. Lowell St., Tucson, AZ, 85721, USA
| | - Christi Williams
- Department of Molecular and Cellular Biology, Life Sciences South, University of Arizona, 1007 E. Lowell St., Tucson, AZ, 85721, USA
| | - Grace Hala'ufia
- Department of Molecular and Cellular Biology, Life Sciences South, University of Arizona, 1007 E. Lowell St., Tucson, AZ, 85721, USA
| | - Alexander D Blythe
- Department of Molecular and Cellular Biology, Life Sciences South, University of Arizona, 1007 E. Lowell St., Tucson, AZ, 85721, USA
| | - Megan Hall
- Translational Genomics Research Institute, 445 N 5th St., Phoenix, AZ, 85004, USA
| | - Rita Sattler
- Department of Translational Neuroscience, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ, 85013, USA
| | | | - Daniela C Zarnescu
- Department of Molecular and Cellular Biology, Life Sciences South, University of Arizona, 1007 E. Lowell St., Tucson, AZ, 85721, USA.
- Cellular and Molecular Physiology, Penn State College of Medicine, 500 University Drive Crescent Building C4605, Hershey, PA, 17033, USA.
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Gittings LM, Alsop EB, Antone J, Singer M, Whitsett TG, Sattler R, Van Keuren-Jensen K. Cryptic exon detection and transcriptomic changes revealed in single-nuclei RNA sequencing of C9ORF72 patients spanning the ALS-FTD spectrum. Acta Neuropathol 2023; 146:433-450. [PMID: 37466726 PMCID: PMC10412668 DOI: 10.1007/s00401-023-02599-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 06/09/2023] [Accepted: 06/12/2023] [Indexed: 07/20/2023]
Abstract
The C9ORF72-linked diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are characterized by the nuclear depletion and cytoplasmic accumulation of TAR DNA-binding protein 43 (TDP-43). Recent studies have shown that the loss of TDP-43 function leads to the inclusion of cryptic exons (CE) in several RNA transcript targets of TDP-43. Here, we show for the first time the detection of CEs in a single-nuclei RNA sequencing (snRNA-seq) dataset obtained from frontal and occipital cortices of C9ORF72 patients that phenotypically span the ALS-FTD disease spectrum. We assessed each cellular cluster for detection of recently described TDP-43-induced CEs. Transcripts containing CEs in the genes STMN2 and KALRN were detected in the frontal cortex of all C9ORF72 disease groups with the highest frequency in excitatory neurons in the C9ORF72-FTD group. Within the excitatory neurons, the cluster with the highest proportion of cells containing a CE had transcriptomic similarities to von Economo neurons, which are known to be vulnerable to TDP-43 pathology and selectively lost in C9ORF72-FTD. Differential gene expression and pathway analysis of CE-containing neurons revealed multiple dysregulated metabolic processes. Our findings reveal novel insights into the transcriptomic changes of neurons vulnerable to TDP-43 pathology.
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Affiliation(s)
- Lauren M Gittings
- Department of Translational Neuroscience, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ, 85013, USA
| | - Eric B Alsop
- Neurogenomics Division, Translational Genomics Research Institute, part of City of Hope, Phoenix, AZ, USA
| | - Jerry Antone
- Neurogenomics Division, Translational Genomics Research Institute, part of City of Hope, Phoenix, AZ, USA
| | - Mo Singer
- Department of Translational Neuroscience, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ, 85013, USA
| | - Timothy G Whitsett
- Neurogenomics Division, Translational Genomics Research Institute, part of City of Hope, Phoenix, AZ, USA
| | - Rita Sattler
- Department of Translational Neuroscience, Barrow Neurological Institute, 350 W Thomas Road, Phoenix, AZ, 85013, USA.
| | - Kendall Van Keuren-Jensen
- Neurogenomics Division, Translational Genomics Research Institute, part of City of Hope, Phoenix, AZ, USA.
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Lorenzini I, Alsop E, Levy J, Gittings LM, Lall D, Rabichow BE, Moore S, Pevey R, Bustos LM, Burciu C, Bhatia D, Singer M, Saul J, McQuade A, Tzioras M, Mota TA, Logemann A, Rose J, Almeida S, Gao FB, Marks M, Donnelly CJ, Hutchins E, Hung ST, Ichida J, Bowser R, Spires-Jones T, Blurton-Jones M, Gendron TF, Baloh RH, Van Keuren-Jensen K, Sattler R. Moderate intrinsic phenotypic alterations in C9orf72 ALS/FTD iPSC-microglia despite the presence of C9orf72 pathological features. Front Cell Neurosci 2023; 17:1179796. [PMID: 37346371 PMCID: PMC10279871 DOI: 10.3389/fncel.2023.1179796] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 05/05/2023] [Indexed: 06/23/2023] Open
Abstract
While motor and cortical neurons are affected in C9orf72 amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD), it remains largely unknown if and how non-neuronal cells induce or exacerbate neuronal damage. We differentiated C9orf72 ALS/FTD patient-derived induced pluripotent stem cells into microglia (iPSC-MG) and examined their intrinsic phenotypes. Similar to iPSC motor neurons, C9orf72 ALS/FTD iPSC-MG mono-cultures form G4C2 repeat RNA foci, exhibit reduced C9orf72 protein levels, and generate dipeptide repeat proteins. Healthy control and C9orf72 ALS/FTD iPSC-MG equally express microglial specific genes and perform microglial functions, including inflammatory cytokine release and phagocytosis of extracellular cargos, such as synthetic amyloid beta peptides and healthy human brain synaptoneurosomes. RNA sequencing analysis revealed select transcriptional changes of genes associated with neuroinflammation or neurodegeneration in diseased microglia yet no significant differentially expressed microglial-enriched genes. Moderate molecular and functional differences were observed in C9orf72 iPSC-MG mono-cultures despite the presence of C9orf72 pathological features suggesting that a diseased microenvironment may be required to induce phenotypic changes in microglial cells and the associated neuronal dysfunction seen in C9orf72 ALS/FTD neurodegeneration.
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Affiliation(s)
- Ileana Lorenzini
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Eric Alsop
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, United States
| | - Jennifer Levy
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Lauren M. Gittings
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Deepti Lall
- Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Regenerative Medicine Institute, Los Angeles, CA, United States
| | - Benjamin E. Rabichow
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Stephen Moore
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Ryan Pevey
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Lynette M. Bustos
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Camelia Burciu
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Divya Bhatia
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Mo Singer
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Justin Saul
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Amanda McQuade
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, United States
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, United States
| | - Makis Tzioras
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
- Centre for Brain Discovery Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas A. Mota
- Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Regenerative Medicine Institute, Los Angeles, CA, United States
| | - Amber Logemann
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, United States
| | - Jamie Rose
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
- Centre for Brain Discovery Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Sandra Almeida
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Michael Marks
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Christopher J. Donnelly
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Elizabeth Hutchins
- Neurogenomics Division, Translational Genomics Research Institute, Phoenix, AZ, United States
| | - Shu-Ting Hung
- Department of Stem Cell Biology Regenerative Medicine, USC Keck School of Medicine, Los Angeles, CA, United States
| | - Justin Ichida
- Department of Stem Cell Biology Regenerative Medicine, USC Keck School of Medicine, Los Angeles, CA, United States
| | - Robert Bowser
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
| | - Tara Spires-Jones
- UK Dementia Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
- Centre for Brain Discovery Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Mathew Blurton-Jones
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, United States
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, United States
| | - Tania F. Gendron
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Jacksonville, FL, United States
| | - Robert H. Baloh
- Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Regenerative Medicine Institute, Los Angeles, CA, United States
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | | | - Rita Sattler
- Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, United States
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Bolukbasi E, Woodling NS, Ivanov DK, Adcott J, Foley A, Rajasingam A, Gittings LM, Aleyakpo B, Niccoli T, Thornton JM, Partridge L. Cell type-specific modulation of healthspan by Forkhead family transcription factors in the nervous system. Proc Natl Acad Sci U S A 2021; 118:2011491118. [PMID: 33593901 PMCID: PMC7923679 DOI: 10.1073/pnas.2011491118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Reduced activity of insulin/insulin-like growth factor signaling (IIS) increases healthy lifespan among diverse animal species. Downstream of IIS, multiple evolutionarily conserved transcription factors (TFs) are required; however, distinct TFs are likely responsible for these effects in different tissues. Here we have asked which TFs can extend healthy lifespan within distinct cell types of the adult nervous system in Drosophila Starting from published single-cell transcriptomic data, we report that forkhead (FKH) is endogenously expressed in neurons, whereas forkhead-box-O (FOXO) is expressed in glial cells. Accordingly, we find that neuronal FKH and glial FOXO exert independent prolongevity effects. We have further explored the role of neuronal FKH in a model of Alzheimer's disease-associated neuronal dysfunction, where we find that increased neuronal FKH preserves behavioral function and reduces ubiquitinated protein aggregation. Finally, using transcriptomic profiling, we identify Atg17, a member of the Atg1 autophagy initiation family, as one FKH-dependent target whose neuronal overexpression is sufficient to extend healthy lifespan. Taken together, our results underscore the importance of cell type-specific mapping of TF activity to preserve healthy function with age.
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Affiliation(s)
- Ekin Bolukbasi
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Nathaniel S Woodling
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Dobril K Ivanov
- European Bioinformatics Institute, European Molecular Biology Laboratory, Cambridge CB10 1SD, United Kingdom
- UK Dementia Research Institute, Cardiff University, Cardiff CF24 4HQ, United Kingdom
| | - Jennifer Adcott
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Andrea Foley
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Arjunan Rajasingam
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Lauren M Gittings
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Benjamin Aleyakpo
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Teresa Niccoli
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - Janet M Thornton
- European Bioinformatics Institute, European Molecular Biology Laboratory, Cambridge CB10 1SD, United Kingdom
| | - Linda Partridge
- Institute of Healthy Ageing, University College London, London WC1E 6BT, United Kingdom;
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
- Department of Biological Mechanisms of Ageing, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
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Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that is characterized by degeneration of both upper and lower motor neurons and subsequent progressive loss of muscle function. Within the last decade, significant progress has been made in the understanding of the etiology and pathobiology of the disease; however, treatment options remain limited and only two drugs, which exert a modest effect on survival, are approved for ALS treatment in the US. Therefore, the search for effective ALS therapies continues, and over 60 clinical trials are in progress for patients with ALS and other therapeutics are at the pre-clinical stage of development. Recent advances in understanding the genetics, pathology, and molecular mechanisms of ALS have led to the identification of novel targets and strategies that are being used in emerging ALS therapeutic interventions. Here, we review the current status and mechanisms of action of a selection of emerging ALS therapies in pre-clinical or early clinical development, including gene therapy, immunotherapy, and strategies that target neuroinflammation, phase separation, and protein clearance.
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Affiliation(s)
- Lauren M Gittings
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Rita Sattler
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, AZ, USA
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Gittings LM, Boeynaems S, Lightwood D, Clargo A, Topia S, Nakayama L, Troakes C, Mann DMA, Gitler AD, Lashley T, Isaacs AM. Symmetric dimethylation of poly-GR correlates with disease duration in C9orf72 FTLD and ALS and reduces poly-GR phase separation and toxicity. Acta Neuropathol 2020; 139:407-410. [PMID: 31832771 PMCID: PMC6989575 DOI: 10.1007/s00401-019-02104-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/22/2019] [Accepted: 11/22/2019] [Indexed: 12/18/2022]
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Gittings LM, Foti SC, Benson BC, Gami-Patel P, Isaacs AM, Lashley T. Heterogeneous nuclear ribonucleoproteins R and Q accumulate in pathological inclusions in FTLD-FUS. Acta Neuropathol Commun 2019; 7:18. [PMID: 30755280 PMCID: PMC6371513 DOI: 10.1186/s40478-019-0673-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 02/03/2019] [Indexed: 12/14/2022] Open
Abstract
Frontotemporal lobar degeneration (FTLD) is pathologically subdivided based on the presence of particular pathological proteins that are identified in inclusion bodies observed post-mortem. The FTLD-FUS subgroup is defined by the presence of the fused in sarcoma protein (FUS) in pathological inclusions. FUS is a heterogeneous nuclear ribonucleoprotein (hnRNP) protein and a member of the FET (FUS, EWS, TAF15) protein family. It shuttles between the nucleus and cytoplasm, and has been implicated in many cellular functions including translation, splicing, and RNA transport. EWS, TAF15 and the nuclear import receptor transportin have been shown to co-accumulate with FUS in neuronal inclusions specifically in FTLD-FUS, with transportin-positive inclusions most frequently observed. Here, we report the identification of hnRNP R and hnRNP Q in neuronal cytoplasmic and intranuclear inclusions in the frontal cortex and hippocampus of FTLD-FUS patients, as frequently as transportin. hnRNP R and hnRNP Q were not found in the characteristic pathological inclusions observed in FTLD-TDP (subtypes A-C). Additionally, we studied the expression of hnRNP R in the frontal and temporal cortices from patients with FTLD and found significantly increased expression of the heterogeneous nuclear ribonucleoprotein R in several FTLD disease groups. Our identification of the frequent presence of hnRNP R and hnRNP Q in FTLD-FUS inclusions suggests a potential role for these hnRNPs in FTLD-FUS pathogenesis and supports the role of dysfunctional RNA metabolism in FTLD.
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Zarouchlioti C, Parfitt DA, Li W, Gittings LM, Cheetham ME. DNAJ Proteins in neurodegeneration: essential and protective factors. Philos Trans R Soc Lond B Biol Sci 2018; 373:20160534. [PMID: 29203718 PMCID: PMC5717533 DOI: 10.1098/rstb.2016.0534] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2017] [Indexed: 12/16/2022] Open
Abstract
Maintenance of protein homeostasis is vitally important in post-mitotic cells, particularly neurons. Neurodegenerative diseases such as polyglutamine expansion disorders-like Huntington's disease or spinocerebellar ataxia (SCA), Alzheimer's disease, fronto-temporal dementia (FTD), amyotrophic lateral sclerosis (ALS) and Parkinson's disease-are often characterized by the presence of inclusions of aggregated protein. Neurons contain complex protein networks dedicated to protein quality control and maintaining protein homeostasis, or proteostasis. Molecular chaperones are a class of proteins with prominent roles in maintaining proteostasis, which act to bind and shield hydrophobic regions of nascent or misfolded proteins while allowing correct folding, conformational changes and enabling quality control. There are many different families of molecular chaperones with multiple functions in proteostasis. The DNAJ family of molecular chaperones is the largest chaperone family and is defined by the J-domain, which regulates the function of HSP70 chaperones. DNAJ proteins can also have multiple other protein domains such as ubiquitin-interacting motifs or clathrin-binding domains leading to diverse and specific roles in the cell, including targeting client proteins for degradation via the proteasome, chaperone-mediated autophagy and uncoating clathrin-coated vesicles. DNAJ proteins can also contain ER-signal peptides or mitochondrial leader sequences, targeting them to specific organelles in the cell. In this review, we discuss the multiple roles of DNAJ proteins and in particular focus on the role of DNAJ proteins in protecting against neurodegenerative diseases caused by misfolded proteins. We also discuss the role of DNAJ proteins as direct causes of inherited neurodegeneration via mutations in DNAJ family genes.This article is part of the theme issue 'Heat shock proteins as modulators and therapeutic targets of chronic disease: an integrated perspective'.
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Affiliation(s)
| | - David A Parfitt
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1 V 9EL, UK
| | - Wenwen Li
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1 V 9EL, UK
| | - Lauren M Gittings
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1 V 9EL, UK
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