1
|
Hegde M, Vasquez V, Kodavati M, Mitra J, Vendula I, Hamilton D, Garruto R, Rao KS. Mitochondria-Targeted Oligomeric α-Synuclein Induces TOM40 Degradation and Mitochondrial Dysfunction in Parkinson's Disease and Parkinsonism-Dementia of Guam. RESEARCH SQUARE 2024:rs.3.rs-3970470. [PMID: 38464024 PMCID: PMC10925433 DOI: 10.21203/rs.3.rs-3970470/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Mitochondrial dysfunction is a central aspect of Parkinson's disease (PD) pathology, yet the underlying mechanisms are not fully understood. This study investigates the link between α-Synuclein (α-Syn) pathology and the loss of translocase of the outer mitochondrial membrane 40 (TOM40), unraveling its implications for mitochondrial dysfunctions in neurons. We discovered that TOM40 protein depletion occurs in the brains of patients with Guam Parkinsonism Dementia (Guam PD) and cultured neurons expressing α-Syn proteinopathy, notably, without corresponding changes in TOM40 mRNA levels. Cultured neurons expressing α-Syn mutants, with or without a mitochondria-targeting signal (MTS) underscore the role of α-Syn's mitochondrial localization in inducing TOM40 degradation. Parkinson's Disease related etiological factors, such as 6-hydroxy dopamine or ROS/metal ions stress, which promote α-Syn oligomerization, exacerbate TOM40 depletion in PD patient-derived cells with SNCA gene triplication. Although α-Syn interacts with both TOM40 and TOM20 in the outer mitochondrial membrane, degradation is selective for TOM40, which occurs via the ubiquitin-proteasome system (UPS) pathway. Our comprehensive analyses using Seahorse technology, mitochondrial DNA sequencing, and damage assessments, demonstrate that mutant α-Syn-induced TOM40 loss results in mitochondrial dysfunction, characterized by reduced membrane potential, accumulation of mtDNA damage, deletion/insertion mutations, and altered oxygen consumption rates. Notably, ectopic supplementation of TOM40 or reducing pathological forms of α-Syn using ADP-ribosylation inhibitors ameliorate these mitochondrial defects, suggesting potential therapeutic avenues. In conclusion, our findings provide crucial mechanistic insights into how α-Syn accumulation leads to TOM40 degradation and mitochondrial dysfunction, offering insights for targeted interventions to alleviate mitochondrial defects in PD.
Collapse
Affiliation(s)
| | | | | | - Joy Mitra
- Houston Methodist Research Institute
| | | | - Dale Hamilton
- Center for Bioenergetics, Houston Methodist Research Institute
| | | | | |
Collapse
|
2
|
Horvath JD, Casas M, Kutchukian C, Sánchez SC, Pergande MR, Cologna SM, Simó S, Dixon RE, Dickson EJ. α-Synuclein-dependent increases in PIP5K1γ drive inositol signaling to promote neurotoxicity. Cell Rep 2023; 42:113244. [PMID: 37838947 PMCID: PMC11010634 DOI: 10.1016/j.celrep.2023.113244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 08/09/2023] [Accepted: 09/25/2023] [Indexed: 10/17/2023] Open
Abstract
Anomalous aggregation of α-synuclein (α-Syn) is a pathological hallmark of many degenerative synucleinopathies including Lewy body dementia (LBD) and Parkinson's disease (PD). Despite its strong link to disease, the precise molecular mechanisms that link α-Syn aggregation to neurodegeneration have yet to be elucidated. Here, we find that elevated α-Syn leads to an increase in the plasma membrane (PM) phosphoinositide PI(4,5)P2, which precipitates α-Syn aggregation and drives toxic increases in mitochondrial Ca2+ and reactive oxygen species leading to neuronal death. Upstream of this toxic signaling pathway is PIP5K1γ, whose abundance and localization is enhanced at the PM by α-Syn-dependent increases in ARF6. Selective inhibition of PIP5K1γ or knockout of ARF6 in neurons rescues α-Syn aggregation and cellular phenotypes of toxicity. Collectively, our data suggest that modulation of phosphoinositide metabolism may be a therapeutic target to slow neurodegeneration for PD and other related neurodegenerative disorders.
Collapse
Affiliation(s)
- Jonathan D Horvath
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
| | - Maria Casas
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
| | - Candice Kutchukian
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
| | - Sara Creus Sánchez
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
| | | | | | - Sergi Simó
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, CA 95616, USA
| | - Rose E Dixon
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA
| | - Eamonn J Dickson
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA.
| |
Collapse
|
3
|
A A, W C, N N, L M, M D, Zhang DD. α-Syn overexpression, NRF2 suppression, and enhanced ferroptosis create a vicious cycle of neuronal loss in Parkinson's disease. Free Radic Biol Med 2022; 192:130-140. [PMID: 36150560 PMCID: PMC9841923 DOI: 10.1016/j.freeradbiomed.2022.09.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/08/2022] [Accepted: 09/16/2022] [Indexed: 01/18/2023]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disorder, affecting millions each year. Most PD cases (∼90%) are sporadic, resulting from the age-dependent accumulation of pathogenic effects. One key pathological hallmark of PD progression is the accumulation of alpha-synuclein (α-syn), which has been shown to negatively affect neuronal function and viability. Here, using 3- and 6-month-old Nrf2+/+ and Nrf2-/- mice overexpressing human α-syn (PD model), we show that loss of NRF2 increases markers of ferroptosis across PD-relevant brain regions. Increased ferroptosis was associated with an age- and genotype-dependent increase in α-syn pathology and behavioral deficits. Finally, we demonstrate that α-syn overexpression sensitizes neuronal cells and ex vivo brain slices to ferroptosis induction, which may be due to α-syn decreasing NRF2 protein levels. Altogether, these results indicate that NRF2 is a critical anti-ferroptotic mediator of neuronal survival, and that the vicious cycle of α-syn overexpression and NRF2 suppression, leading to enhanced neuronal ferroptotic cell death, could represent a targetable and currently untapped means of preventing PD onset and progression.
Collapse
Affiliation(s)
- Anandhan A
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA
| | - Chen W
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA
| | - Nguyen N
- Department of Neurology, University of Arizona, Tucson, AZ, USA
| | - Madhavan L
- Department of Neurology, University of Arizona, Tucson, AZ, USA; Evelyn F McKnight Brain Institute and Bio5 Institute, University of Arizona, Tucson, AZ, USA
| | - Dodson M
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA.
| | - D D Zhang
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA; Arizona Cancer Center, University of Arizona, Tucson, AZ, 85724, USA.
| |
Collapse
|
4
|
Lin CY, Huang CY, Chen CM, Liu HL. Focused Ultrasound-Induced Blood–Brain Barrier Opening Enhanced α-Synuclein Expression in Mice for Modeling Parkinson’s Disease. Pharmaceutics 2022; 14:pharmaceutics14020444. [PMID: 35214176 PMCID: PMC8876143 DOI: 10.3390/pharmaceutics14020444] [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: 01/07/2022] [Revised: 02/09/2022] [Accepted: 02/15/2022] [Indexed: 12/04/2022] Open
Abstract
Parkinson’s disease (PD) is characterized by α-synuclein (αSNCA) aggregation in dopaminergic neurons. Gradual accumulation of αSNCA aggregates in substantia nigra (SN) diminishes the normal functioning of soluble αSNCA, leading to a loss of dopamine (DA) neurons. In this study, we developed focused ultrasound-targeted microbubble destruction (UTMD)-mediated PD model that could generate the disease phenotype via αSNCA CNS gene delivery. The formation of neuronal aggregates was analyzed with immunostaining. To evaluate the DA cell loss, we used tyrosine hydroxylase immunostaining and HPLC analysis on DA and its two metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). This loss of DA was associated with a dose-dependent impairment in motor function, as assessed by the rotarod motor assessment. We demonstrate that UTMD-induced SNCA expression initiates αSNCA aggregation and results in a 50% loss of DA in SN. UTMD-related dose-dependent neuronal loss was identified, and it correlates with the degree of impairment of motor function. In comparison to chemical neurotoxin 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated and conventional intracerebral (IC)-injected animal models of PD, the UTMD-mediated αSNCA-based mouse model offers the advantage of mimicking the rapid development of the PD phenotype. The PD models that we created using UTMD also prove valuable in assessing specific aspects of PD pathogenesis and can serve as a useful PD model for the development of new therapeutic strategies.
Collapse
Affiliation(s)
- Chung-Yin Lin
- Medical Imaging Research Center, Institute for Radiological Research, Chang Gung University, Taoyuan 33302, Taiwan; (C.-Y.L.); (C.-Y.H.)
- Department of Nephrology and Clinical Position Center, Chang Gung Memorial Hospital, Taoyuan 33302, Taiwan
| | - Ching-Yun Huang
- Medical Imaging Research Center, Institute for Radiological Research, Chang Gung University, Taoyuan 33302, Taiwan; (C.-Y.L.); (C.-Y.H.)
| | - Chiung-Mei Chen
- Department of Neurology, Chang Gung Memorial Hospital, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Correspondence: (C.-M.C.); (H.-L.L.); Tel.: +886-3-3281200 (ext. 8729) (C.-M.C.); +886-2-33665416 (H.-L.L.)
| | - Hao-Li Liu
- Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
- Department of Biomedical Engineering, National Taiwan University, Taipei 10617, Taiwan
- Correspondence: (C.-M.C.); (H.-L.L.); Tel.: +886-3-3281200 (ext. 8729) (C.-M.C.); +886-2-33665416 (H.-L.L.)
| |
Collapse
|
5
|
Dominguez-Meijide A, Parrales V, Vasili E, González-Lizárraga F, König A, Lázaro DF, Lannuzel A, Haik S, Del Bel E, Chehín R, Raisman-Vozari R, Michel PP, Bizat N, Outeiro TF. Doxycycline inhibits α-synuclein-associated pathologies in vitro and in vivo. Neurobiol Dis 2021; 151:105256. [PMID: 33429042 DOI: 10.1016/j.nbd.2021.105256] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/29/2020] [Accepted: 01/06/2021] [Indexed: 02/07/2023] Open
Abstract
Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are neurodegenerative disorders characterized by the misfolding and aggregation of alpha-synuclein (aSyn). Doxycycline, a tetracyclic antibiotic shows neuroprotective effects, initially proposed to be due to its anti-inflammatory properties. More recently, an additional mechanism by which doxycycline may exert its neuroprotective effects has been proposed as it has been shown that it inhibits amyloid aggregation. Here, we studied the effects of doxycycline on aSyn aggregation in vivo, in vitro and in a cell free system using real-time quaking induced conversion (RT-QuiC). Using H4, SH-SY5Y and HEK293 cells, we found that doxycycline decreases the number and size of aSyn aggregates in cells. In addition, doxycycline inhibits the aggregation and seeding of recombinant aSyn, and attenuates the production of mitochondrial-derived reactive oxygen species. Finally, we found that doxycycline induces a cellular redistribution of aggregates in a C.elegans animal model of PD, an effect that is associated with a recovery of dopaminergic function. In summary, we provide strong evidence that doxycycline treatment may be an effective strategy against synucleinopathies.
Collapse
Affiliation(s)
- Antonio Dominguez-Meijide
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany; Laboratory of Neuroanatomy and Experimental Neurology, Dept. of Morphological Sciences, CIMUS, IDIS, University of Santiago de Compostela, Santiago de Compostela, Spain; Networking Research Center on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
| | - Valeria Parrales
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France
| | - Eftychia Vasili
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany
| | | | - Annekatrin König
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany
| | - Diana F Lázaro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany
| | - Annie Lannuzel
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France; University Hospital of Pointe-à-Pitre, Neurology Department, route de Chauvel, 97139 Abymes, Guadeloupe
| | - Stéphane Haik
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France; AP-HP, Cellule Nationale de Référence des Maladies de Creutzfeldt-Jakob, University Hospital Pitié-Salpêtrière, Paris F-75013, France
| | - Elaine Del Bel
- Department of Basic and Oral Biology, Faculty of Odontology of Ribeirão Preto, University of São Paulo (USP), Av do Café s/n, São Paulo, Brazil
| | - Rosana Chehín
- Instituto de Investigación en Medicina Molecular y Celular Aplicada (IMMCA) (CONICET-UNT-SIPROSA), Argentina
| | - Rita Raisman-Vozari
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France
| | - Patrick P Michel
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France
| | - Nicolas Bizat
- Paris Brain Institute, Inserm U 1127, CNRS UMR 7225, Sorbonne Université, F-75013 Paris, France; Faculté de Pharmacie de Paris, Paris University, 4 avenue de l'Observatoire, Paris F-75006, France.
| | - Tiago Fleming Outeiro
- Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Goettingen, Goettingen, Germany; Max Planck Institute for Experimental Medicine, Goettingen, Germany; Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne NE2 4HH, UK.
| |
Collapse
|
6
|
Vasquez V, Mitra J, Wang H, Hegde PM, Rao KS, Hegde ML. A multi-faceted genotoxic network of alpha-synuclein in the nucleus and mitochondria of dopaminergic neurons in Parkinson's disease: Emerging concepts and challenges. Prog Neurobiol 2020; 185:101729. [PMID: 31863801 PMCID: PMC7098698 DOI: 10.1016/j.pneurobio.2019.101729] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 10/15/2019] [Accepted: 11/18/2019] [Indexed: 02/06/2023]
Abstract
α-Synuclein is a hallmark amyloidogenic protein component of the Lewy bodies (LBs) present in dopaminergic neurons affected by Parkinson's disease (PD). Despite an enormous increase in emerging knowledge, the mechanism(s) of α-synuclein neurobiology and crosstalk among pathological events that are critical for PD progression remains enigmatic, creating a roadblock for effective intervention strategies. One confounding question is about the potential link between α-synuclein toxicity and genome instability in PD. We previously reported that pro-oxidant metal ions, together with reactive oxygen species (ROS), act as a "double whammy" in dopaminergic neurons by not only inducing genome damage but also inhibiting their repair. Our recent studies identified a direct role for chromatin-bound, oxidized α-synuclein in the induction of DNA strand breaks, which raised the question of a paradoxical role for α-synuclein's DNA binding in neuroprotection versus neurotoxicity. Furthermore, recent advances in our understanding of α-synuclein mediated mitochondrial dysfunction warrants revisiting the topics of α-synuclein pathophysiology in order to devise and assess the efficacy of α-synuclein-targeted interventions. In this review article, we discuss the multi-faceted neurotoxic role of α-synuclein in the nucleus and mitochondria with a particular emphasis on the role of α-synuclein in DNA damage/repair defects. We utilized a protein-DNA binding simulation to identify potential residues in α-synuclein that could mediate its binding to DNA and may be critical for its genotoxic functions. These emerging insights and paradigms may guide new drug targets and therapeutic modalities.
Collapse
Affiliation(s)
- Velmarini Vasquez
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, 77030, USA; Centre for Neuroscience, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, City of Knowledge, Panama
| | - Joy Mitra
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, 77030, USA
| | - Haibo Wang
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, 77030, USA; Center for Neuroregeneration, Department of Neurosurgery, Methodist Neurological Institute, Institute of Academic Medicine, Houston Methodist Hospital, Houston, TX, 77030, USA
| | - Pavana M Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, 77030, USA
| | - K S Rao
- Centre for Neuroscience, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, City of Knowledge, Panama
| | - Muralidhar L Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, 77030, USA; Center for Neuroregeneration, Department of Neurosurgery, Methodist Neurological Institute, Institute of Academic Medicine, Houston Methodist Hospital, Houston, TX, 77030, USA; Weill Cornell Medical College of Cornell University, New York, 10065, USA.
| |
Collapse
|
7
|
Harlen KM, Roush EC, Clayton JE, Martinka S, Hughes TE. Live-Cell Assays for Cell Stress Responses Reveal New Patterns of Cell Signaling Caused by Mutations in Rhodopsin, α-Synuclein and TDP-43. Front Cell Neurosci 2019; 13:535. [PMID: 31920544 PMCID: PMC6930162 DOI: 10.3389/fncel.2019.00535] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 11/19/2019] [Indexed: 12/15/2022] Open
Abstract
Many neurodegenerative diseases induce high levels of sustained cellular stress and alter a number of cellular processes. To examine how different mutations associated with neurodegenerative disease affect cell stress and signaling, we created live-cell assays for endoplasmic reticulum (ER)-mediated cell stress and second messenger signaling. We first examined neurodegenerative mutations associated with direct ER stress by exploring the effect of rhodopsin mutations on ER stress and Ca2+ signaling. The rhodopsin P23H mutation, the most common mutation in autosomal dominant Retinitis Pigmentosa (RP), produced increased ER stress levels compared to wild type (WT) rhodopsin. Moreover, this increase in cell stress correlated with blunted Ca2+ signaling in a stress-dependent manner. Analysis of single-cell Ca2+ signaling profiles revealed unique Ca2+ signaling responses exist in cells expressing WT or P23H rhodopsin, consistent with the idea that second messenger signaling is affected by cell stress. To explore the use of the ER-stress biosensor in neurodegenerative diseases that may not have a direct effect on ER-mediated cell stress, we examined how various mutants of α-synuclein and TDP-43 affected ER stress. Mutants of both α-synuclein and TDP-43 associated with Parkinson's disease (PD) and Amyotrophic lateral sclerosis (ALS) demonstrated increased ER stress compared to WT proteins. To examine the effect of α-synuclein and TDP-43 mutants on cellular signaling, we created a second live-cell assay to monitor changes in cAMP signaling during expression of various forms of α-synuclein and TDP-43. The increased cell stress caused by expression of the mutant proteins was accompanied by changes in phosphodiesterase activity. Both HEK293T and SH-SY5Y cells expressing these proteins displayed a shift towards increased cAMP degradation rates, likely due to increased phosphodiesterase activity. Together these data illustrate how biosensors for cellular stress and signaling can provide nuanced, new views of neurodegenerative disease processes.
Collapse
|
8
|
Jellinger KA. Animal models of synucleinopathies and how they could impact future drug discovery and delivery efforts. Expert Opin Drug Discov 2019; 14:969-982. [DOI: 10.1080/17460441.2019.1638908] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
9
|
Guerrero EN, Mitra J, Wang H, Rangaswamy S, Hegde PM, Basu P, Rao KS, Hegde ML. Amyotrophic lateral sclerosis-associated TDP-43 mutation Q331K prevents nuclear translocation of XRCC4-DNA ligase 4 complex and is linked to genome damage-mediated neuronal apoptosis. Hum Mol Genet 2019; 28:2459-2476. [PMID: 31067307 DOI: 10.1093/hmg/ddz062] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/15/2019] [Accepted: 03/21/2019] [Indexed: 02/06/2023] Open
Abstract
Dominant mutations in the RNA/DNA-binding protein TDP-43 have been linked to amyotrophic lateral sclerosis (ALS). Here, we screened genomic DNA extracted from spinal cord specimens of sporadic ALS patients for mutations in the TARDBP gene and identified a patient specimen with previously reported Q331K mutation. The patient spinal cord tissue with Q331K mutation showed accumulation of higher levels of DNA strand breaks and the DNA double-strand break (DSB) marker γH2AX, compared to age-matched controls, suggesting a role of the Q331K mutation in genome-damage accumulation. Using conditional SH-SY5Y lines ectopically expressing wild-type (WT) or Q331K-mutant TDP-43, we confirmed the increased cytosolic sequestration of the poly-ubiquitinated and aggregated form of mutant TDP-43, which correlated with increased genomic DNA strand breaks, activation of the DNA damage response factors phospho-ataxia-telangiectasia mutated (ATM), phospho-53BP1, γH2AX and neuronal apoptosis. We recently reported the involvement of WT TDP-43 in non-homologous end joining (NHEJ)-mediated DSB repair, where it acts as a scaffold for the recruitment of XRCC4-DNA ligase 4 complex. Here, the mutant TDP-43, due to its reduced interaction and enhanced cytosolic mislocalization, prevented the nuclear translocation of XRCC4-DNA ligase 4. Consistently, the mutant cells showed significantly reduced DNA strand break sealing activity and were sensitized to DNA-damaging drugs. In addition, the mutant cells showed elevated levels of reactive oxygen species, suggesting both dominant negative and loss-of-function effects of the mutation. Together, our study uncovered an association of sporadic Q331K mutation with persistent genome damage accumulation due to both damage induction and repair defects.
Collapse
Affiliation(s)
- Erika N Guerrero
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA.,Center for Neuroscience, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), City of Knowledge, Republic of Panama.,Department of Biotechnology, Acharya Nagarjuna University, Guntur, India
| | - Joy Mitra
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Haibo Wang
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Suganya Rangaswamy
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Pavana M Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - Priyadarshini Basu
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA
| | - K S Rao
- Center for Neuroscience, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), City of Knowledge, Republic of Panama
| | - Muralidhar L Hegde
- Department of Radiation Oncology, Houston Methodist Research Institute, Houston, TX, USA.,Weill Medical College of Cornell University, New York, USA.,Houston Methodist Neurological Institute, Institute of Academic Medicine, Houston Methodist, Houston, USA
| |
Collapse
|