1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Bjork RT, Mortimore NP, Loganathan S, Zarnescu DC. Dysregulation of Translation in TDP-43 Proteinopathies: Deficits in the RNA Supply Chain and Local Protein Production. Front Neurosci 2022; 16:840357. [PMID: 35321094 PMCID: PMC8935057 DOI: 10.3389/fnins.2022.840357] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/09/2022] [Indexed: 12/19/2022] Open
Abstract
Local control of gene expression provides critical mechanisms for regulating development, maintenance and plasticity in the nervous system. Among the strategies known to govern gene expression locally, mRNA transport and translation have emerged as essential for a neuron’s ability to navigate developmental cues, and to establish, strengthen and remove synaptic connections throughout lifespan. Substantiating the role of RNA processing in the nervous system, several RNA binding proteins have been implicated in both developmental and age dependent neurodegenerative disorders. Of these, TDP-43 is an RNA binding protein that has emerged as a common denominator in amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD) and related disorders due to the identification of causative mutations altering its function and its accumulation in cytoplasmic aggregates observed in a significant fraction of ALS/FTD cases, regardless of etiology. TDP-43 is involved in multiple aspects of RNA processing including splicing, transport and translation. Given that one of the early events in disease pathogenesis is mislocalization from the nucleus to the cytoplasm, several studies have focused on elucidating the pathogenic role of TDP-43 in cytoplasmic translation. Here we review recent findings describing TDP-43 translational targets and potential mechanisms of translation dysregulation in TDP-43 proteinopathies across multiple experimental models including cultured cells, flies, mice and patient derived neurons.
Collapse
Affiliation(s)
- Reed T. Bjork
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
- Neuroscience Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, United States
| | - Nicholas P. Mortimore
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
| | | | - Daniela C. Zarnescu
- Department of Molecular and Cellular Biology, University of Arizona, Tucson, AZ, United States
- *Correspondence: Daniela C. Zarnescu,
| |
Collapse
|