1
|
Safren N, Dao TP, Mohan HM, Huang C, Trotter B, Castañeda CA, Paulson H, Barmada S, Sharkey LM. Pathogenic mutations in UBQLN2 exhibit diverse aggregation propensity and neurotoxicity. Sci Rep 2024; 14:6049. [PMID: 38472280 PMCID: PMC10933299 DOI: 10.1038/s41598-024-55582-9] [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: 11/02/2023] [Accepted: 02/26/2024] [Indexed: 03/14/2024] Open
Abstract
The ubiquitin-adaptor protein UBQLN2 promotes degradation of several aggregate-prone proteins implicated in neurodegenerative diseases. Missense UBQLN2 mutations also cause X-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Previously we demonstrated that the liquid-like properties of UBQLN2 molecular assemblies are altered by a specific pathogenic mutation, P506T, and that the propensity of UBQLN2 to aggregate correlated with neurotoxicity. Here, we systematically assess the effects of multiple, spatially distinct ALS/FTD-linked missense mutations on UBQLN2 aggregation propensity, neurotoxicity, phase separation, and autophagic flux. In contrast to what we observed for the P506T mutation, no other tested pathogenic mutant exhibited a clear correlation between aggregation propensity and neurotoxicity. These results emphasize the unique nature of pathogenic UBQLN2 mutations and argue against a generalizable link between aggregation propensity and neurodegeneration in UBQLN2-linked ALS/FTD.
Collapse
Affiliation(s)
- Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
| | - Thuy P Dao
- Departments of Biology and Chemistry, Syracuse University, Syracuse, NY, 13244, USA
| | - Harihar Milaganur Mohan
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
- Cellular and Molecular Biology Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Camellia Huang
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Bryce Trotter
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Carlos A Castañeda
- Departments of Biology and Chemistry, Syracuse University, Syracuse, NY, 13244, USA
| | - Henry Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Sami Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
- Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| |
Collapse
|
2
|
Jagaraj CJ, Shadfar S, Kashani SA, Saravanabavan S, Farzana F, Atkin JD. Molecular hallmarks of ageing in amyotrophic lateral sclerosis. Cell Mol Life Sci 2024; 81:111. [PMID: 38430277 PMCID: PMC10908642 DOI: 10.1007/s00018-024-05164-9] [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: 12/05/2023] [Revised: 01/21/2024] [Accepted: 02/06/2024] [Indexed: 03/03/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, severely debilitating and rapidly progressing disorder affecting motor neurons in the brain, brainstem, and spinal cord. Unfortunately, there are few effective treatments, thus there remains a critical need to find novel interventions that can mitigate against its effects. Whilst the aetiology of ALS remains unclear, ageing is the major risk factor. Ageing is a slowly progressive process marked by functional decline of an organism over its lifespan. However, it remains unclear how ageing promotes the risk of ALS. At the molecular and cellular level there are specific hallmarks characteristic of normal ageing. These hallmarks are highly inter-related and overlap significantly with each other. Moreover, whilst ageing is a normal process, there are striking similarities at the molecular level between these factors and neurodegeneration in ALS. Nine ageing hallmarks were originally proposed: genomic instability, loss of telomeres, senescence, epigenetic modifications, dysregulated nutrient sensing, loss of proteostasis, mitochondrial dysfunction, stem cell exhaustion, and altered inter-cellular communication. However, these were recently (2023) expanded to include dysregulation of autophagy, inflammation and dysbiosis. Hence, given the latest updates to these hallmarks, and their close association to disease processes in ALS, a new examination of their relationship to pathophysiology is warranted. In this review, we describe possible mechanisms by which normal ageing impacts on neurodegenerative mechanisms implicated in ALS, and new therapeutic interventions that may arise from this.
Collapse
Affiliation(s)
- Cyril Jones Jagaraj
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sina Shadfar
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sara Assar Kashani
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Sayanthooran Saravanabavan
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Fabiha Farzana
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia
| | - Julie D Atkin
- MND Research Centre, Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, 75 Talavera Road, Sydney, NSW, 2109, Australia.
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Melbourne, VIC, 3086, Australia.
| |
Collapse
|
3
|
Cunha-Oliveira T, Montezinho L, Simões RF, Carvalho M, Ferreiro E, Silva FSG. Mitochondria: A Promising Convergent Target for the Treatment of Amyotrophic Lateral Sclerosis. Cells 2024; 13:248. [PMID: 38334639 PMCID: PMC10854804 DOI: 10.3390/cells13030248] [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: 12/07/2023] [Revised: 01/18/2024] [Accepted: 01/24/2024] [Indexed: 02/10/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the progressive loss of motor neurons, for which current treatment options are limited. Recent studies have shed light on the role of mitochondria in ALS pathogenesis, making them an attractive therapeutic intervention target. This review contains a very comprehensive critical description of the involvement of mitochondria and mitochondria-mediated mechanisms in ALS. The review covers several key areas related to mitochondria in ALS, including impaired mitochondrial function, mitochondrial bioenergetics, reactive oxygen species, metabolic processes and energy metabolism, mitochondrial dynamics, turnover, autophagy and mitophagy, impaired mitochondrial transport, and apoptosis. This review also highlights preclinical and clinical studies that have investigated various mitochondria-targeted therapies for ALS treatment. These include strategies to improve mitochondrial function, such as the use of dichloroacetate, ketogenic and high-fat diets, acetyl-carnitine, and mitochondria-targeted antioxidants. Additionally, antiapoptotic agents, like the mPTP-targeting agents minocycline and rasagiline, are discussed. The paper aims to contribute to the identification of effective mitochondria-targeted therapies for ALS treatment by synthesizing the current understanding of the role of mitochondria in ALS pathogenesis and reviewing potential convergent therapeutic interventions. The complex interplay between mitochondria and the pathogenic mechanisms of ALS holds promise for the development of novel treatment strategies to combat this devastating disease.
Collapse
Affiliation(s)
- Teresa Cunha-Oliveira
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Liliana Montezinho
- Center for Investigation Vasco da Gama (CIVG), Escola Universitária Vasco da Gama, 3020-210 Coimbra, Portugal;
| | - Rui F. Simões
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Marcelo Carvalho
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Elisabete Ferreiro
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Filomena S. G. Silva
- CNC—Center for Neuroscience and Cell Biology, CIBB—Centre for Innovative Biomedicine and Biotechnology, University of Coimbra, 3004-504 Coimbra, Portugal
- Mitotag Lda, Biocant Park, 3060-197 Cantanhede, Portugal
| |
Collapse
|
4
|
Todd TW, Shao W, Zhang YJ, Petrucelli L. The endolysosomal pathway and ALS/FTD. Trends Neurosci 2023; 46:1025-1041. [PMID: 37827960 PMCID: PMC10841821 DOI: 10.1016/j.tins.2023.09.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 08/23/2023] [Accepted: 09/19/2023] [Indexed: 10/14/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are considered to be part of a disease spectrum that is associated with causative mutations and risk variants in a wide range of genes. Mounting evidence indicates that several of these genes are linked to the endolysosomal system, highlighting the importance of this pathway in ALS/FTD. Although many studies have focused on how disruption of this pathway impacts on autophagy, recent findings reveal that this may not be the whole picture: specifically, disrupting autophagy may not be sufficient to induce disease, whereas disrupting the endolysosomal system could represent a crucial pathogenic driver. In this review we discuss the connections between ALS/FTD and the endolysosomal system, including a breakdown of how disease-associated genes are implicated in this pathway. We also explore the potential downstream consequences of disrupting endolysosomal activity in the brain, outside of an effect on autophagy.
Collapse
Affiliation(s)
- Tiffany W Todd
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Wei Shao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
| | - Yong-Jie Zhang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN, USA.
| |
Collapse
|
5
|
Idera A, Sharkey LM, Kurauchi Y, Kadoyama K, Paulson HL, Katsuki H, Seki T. Wild-type and pathogenic forms of ubiquilin 2 differentially modulate components of the autophagy-lysosome pathways. J Pharmacol Sci 2023; 152:182-192. [PMID: 37257946 DOI: 10.1016/j.jphs.2023.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/14/2023] [Accepted: 05/08/2023] [Indexed: 06/02/2023] Open
Abstract
Missense mutations of ubiquilin 2 (UBQLN2) have been identified to cause X-linked amyotrophic lateral sclerosis (ALS). Proteasome-mediated protein degradation is reported to be impaired by ALS-associated mutations of UBQLN2. However, it remains unknown how these mutations affect autophagy-lysosome protein degradation, which consists of macroautophagy (MA), microautophagy (mA), and chaperone-mediated autophagy (CMA). Using a CMA/mA fluorescence reporter we found that overexpression of wild-type UBQLN2 impairs CMA. Conversely, knockdown of endogenous UBQLN2 increases CMA activity, suggesting that normally UBQLN2 negatively regulates CMA. ALS-associated mutant forms of UBQLN2 exacerbate this impairment of CMA. Using cells stably transfected with wild-type or ALS-associated mutant UBQLN2, we further determined that wild-type UBQLN2 increased the ratio of LAMP2A (a CMA-related protein) to LAMP1 (a lysosomal protein). This could represent a compensatory reaction to the impairment of CMA by wild-type UBQLN2. However, ALS-associated mutant UBQLN2 failed to show this compensation, exacerbating the impairment of CMA by mutant UBQLN2. We further demonstrated that ALS-associated mutant forms of UBQLN2 also impair MA, but wild-type UBQLN2 does not. These results support the view that ALS-associated mutant forms of UBQLN2 impair both CMA and MA which may contribute to the neurodegeneration observed in patients with UBQLN2-mediated ALS.
Collapse
Affiliation(s)
- Akiko Idera
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Yuki Kurauchi
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Keiichi Kadoyama
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Japan
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI, USA
| | - Hiroshi Katsuki
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan
| | - Takahiro Seki
- Department of Chemico-Pharmacological Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan; Department of Pharmacology, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, Japan.
| |
Collapse
|
6
|
Themistokleous C, Bagnoli E, Parulekar R, M K Muqit M. Role of autophagy pathway in Parkinson's disease and related Genetic Neurological disorders. J Mol Biol 2023:168144. [PMID: 37182812 DOI: 10.1016/j.jmb.2023.168144] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 05/05/2023] [Accepted: 05/08/2023] [Indexed: 05/16/2023]
Abstract
The elucidation of the function of the PINK1 protein kinase and Parkin ubiquitin E3 ligase in the elimination of damaged mitochondria by autophagy (mitophagy) has provided unprecedented understanding of the mechanistic pathways underlying Parkinson's disease (PD). We provide a comprehensive overview of the general importance of autophagy in Parkinson's disease and related disorders of the central nervous system. This reveals a critical link between autophagy and neurodegenerative and neurodevelopmental disorders and suggests that strategies to modulate mitophagy may have greater relevance in the CNS beyond PD.
Collapse
Affiliation(s)
- Christos Themistokleous
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK of Dundee, Dundee, DD1 5EH, UK; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Enrico Bagnoli
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK of Dundee, Dundee, DD1 5EH, UK; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Ramaa Parulekar
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK of Dundee, Dundee, DD1 5EH, UK
| | - Miratul M K Muqit
- MRC Protein Phosphorylation and Ubiquitylation Unit, Sir James Black Centre, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK of Dundee, Dundee, DD1 5EH, UK; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA.
| |
Collapse
|
7
|
Gelon PA, Dutchak PA, Sephton CF. Synaptic dysfunction in ALS and FTD: anatomical and molecular changes provide insights into mechanisms of disease. Front Mol Neurosci 2022; 15:1000183. [PMID: 36263379 PMCID: PMC9575515 DOI: 10.3389/fnmol.2022.1000183] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/01/2022] [Indexed: 11/29/2022] Open
Abstract
Synaptic loss is a pathological feature of all neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). ALS is a disease of the cortical and spinal motor neurons resulting in fatal paralysis due to denervation of muscles. FTD is a form of dementia that primarily affects brain regions controlling cognition, language and behavior. Once classified as two distinct diseases, ALS and FTD are now considered as part of a common disease spectrum based on overlapping clinical, pathological and genetic evidence. At the cellular level, aggregation of common proteins and overlapping gene susceptibilities are shared in both ALS and FTD. Despite the convergence of these two fields of research, the underlying disease mechanisms remain elusive. However, recent discovers from ALS and FTD patient studies and models of ALS/FTD strongly suggests that synaptic dysfunction is an early event in the disease process and a unifying hallmark of these diseases. This review provides a summary of the reported anatomical and cellular changes that occur in cortical and spinal motor neurons in ALS and FTD tissues and models of disease. We also highlight studies that identify changes in the proteome and transcriptome of ALS and FTD models and provide a conceptual overview of the processes that contribute to synaptic dysfunction in these diseases. Due to space limitations and the vast number of publications in the ALS and FTD fields, many articles have not been discussed in this review. As such, this review focuses on the three most common shared mutations in ALS and FTD, the hexanucleuotide repeat expansion within intron 1 of chromosome 9 open reading frame 72 (C9ORF72), transactive response DNA binding protein 43 (TARDBP or TDP-43) and fused in sarcoma (FUS), with the intention of highlighting common pathways that promote synaptic dysfunction in the ALS-FTD disease spectrum.
Collapse
|
8
|
Lin BC, Higgins NR, Phung TH, Monteiro MJ. UBQLN proteins in health and disease with a focus on UBQLN2 in ALS/FTD. FEBS J 2022; 289:6132-6153. [PMID: 34273246 PMCID: PMC8761781 DOI: 10.1111/febs.16129] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/08/2021] [Accepted: 07/16/2021] [Indexed: 01/12/2023]
Abstract
Ubiquilin (UBQLN) proteins are a dynamic and versatile family of proteins found in all eukaryotes that function in the regulation of proteostasis. Besides their canonical function as shuttle factors in delivering misfolded proteins to the proteasome and autophagy systems for degradation, there is emerging evidence that UBQLN proteins play broader roles in proteostasis. New information suggests the proteins function as chaperones in protein folding, protecting proteins prior to membrane insertion, and as guardians for mitochondrial protein import. In this review, we describe the evidence for these different roles, highlighting how different domains of the proteins impart these functions. We also describe how changes in the structure and phase separation properties of UBQLNs may regulate their activity and function. Finally, we discuss the pathogenic mechanisms by which mutations in UBQLN2 cause amyotrophic lateral sclerosis and frontotemporal dementia. We describe the animal model systems made for different UBQLN2 mutations and how lessons learnt from these systems provide fundamental insight into the molecular mechanisms by which UBQLN2 mutations drive disease pathogenesis through disturbances in proteostasis.
Collapse
Affiliation(s)
- Brian C. Lin
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA,Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Nicole R. Higgins
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA,Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Trong H. Phung
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mervyn J. Monteiro
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, USA,Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA,Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA,Program in Molecular Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| |
Collapse
|
9
|
Lu G, Wang Y, Shi Y, Zhang Z, Huang C, He W, Wang C, Shen HM. Autophagy in health and disease: From molecular mechanisms to therapeutic target. MedComm (Beijing) 2022; 3:e150. [PMID: 35845350 PMCID: PMC9271889 DOI: 10.1002/mco2.150] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/01/2022] [Accepted: 06/02/2022] [Indexed: 02/05/2023] Open
Abstract
Macroautophagy/autophagy is an evolutionally conserved catabolic process in which cytosolic contents, such as aggregated proteins, dysfunctional organelle, or invading pathogens, are sequestered by the double‐membrane structure termed autophagosome and delivered to lysosome for degradation. Over the past two decades, autophagy has been extensively studied, from the molecular mechanisms, biological functions, implications in various human diseases, to development of autophagy‐related therapeutics. This review will focus on the latest development of autophagy research, covering molecular mechanisms in control of autophagosome biogenesis and autophagosome–lysosome fusion, and the upstream regulatory pathways including the AMPK and MTORC1 pathways. We will also provide a systematic discussion on the implication of autophagy in various human diseases, including cancer, neurodegenerative disorders (Alzheimer disease, Parkinson disease, Huntington's disease, and Amyotrophic lateral sclerosis), metabolic diseases (obesity and diabetes), viral infection especially SARS‐Cov‐2 and COVID‐19, cardiovascular diseases (cardiac ischemia/reperfusion and cardiomyopathy), and aging. Finally, we will also summarize the development of pharmacological agents that have therapeutic potential for clinical applications via targeting the autophagy pathway. It is believed that decades of hard work on autophagy research is eventually to bring real and tangible benefits for improvement of human health and control of human diseases.
Collapse
Affiliation(s)
- Guang Lu
- Department of Physiology, Zhongshan School of Medicine Sun Yat-sen University Guangzhou China
| | - Yu Wang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine Sichuan University and Collaborative Innovation Center for Biotherapy Chengdu China
| | - Yin Shi
- Department of Biochemistry Zhejiang University School of Medicine Hangzhou China
| | - Zhe Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine Sichuan University and Collaborative Innovation Center for Biotherapy Chengdu China
| | - Canhua Huang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and West China School of Basic Medical Sciences & Forensic Medicine Sichuan University and Collaborative Innovation Center for Biotherapy Chengdu China
| | - Weifeng He
- State Key Laboratory of Trauma, Burn and Combined Injury, Institute of Burn Research Southwest Hospital Army Medical University Chongqing China
| | - Chuang Wang
- Department of Pharmacology, Provincial Key Laboratory of Pathophysiology Ningbo University School of Medicine Ningbo Zhejiang China
| | - Han-Ming Shen
- Department of Biomedical Sciences, Faculty of Health Sciences, Ministry of Education Frontiers Science Center for Precision Oncology University of Macau Macau China
| |
Collapse
|
10
|
Dao TP, Yang Y, Presti MF, Cosgrove MS, Hopkins JB, Ma W, Loh SN, Castañeda CA. Mechanistic insights into enhancement or inhibition of phase separation by different polyubiquitin chains. EMBO Rep 2022; 23:e55056. [PMID: 35762418 PMCID: PMC9346500 DOI: 10.15252/embr.202255056] [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: 03/15/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 12/03/2022] Open
Abstract
Ubiquitin‐binding shuttle UBQLN2 mediates crosstalk between proteasomal degradation and autophagy, likely via interactions with K48‐ and K63‐linked polyubiquitin chains, respectively. UBQLN2 comprises self‐associating regions that drive its homotypic liquid–liquid phase separation (LLPS). Specific interactions between one of these regions and ubiquitin inhibit UBQLN2 LLPS. Here, we show that, unlike ubiquitin, the effects of multivalent polyubiquitin chains on UBQLN2 LLPS are highly dependent on chain types. Specifically, K11‐Ub4 and K48‐Ub4 chains generally inhibit UBQLN2 LLPS, whereas K63‐Ub4, M1‐Ub4 chains, and a designed tetrameric ubiquitin construct significantly enhance LLPS. We demonstrate that these opposing effects stem from differences in chain conformations but not in affinities between chains and UBQLN2. Chains with extended conformations and increased accessibility to the ubiquitin‐binding surface promote UBQLN2 LLPS by enabling a switch between homotypic to partially heterotypic LLPS that is driven by both UBQLN2 self‐interactions and interactions between multiple UBQLN2 units with each polyubiquitin chain. Our study provides mechanistic insights into how the structural and conformational properties of polyubiquitin chains contribute to heterotypic LLPS with ubiquitin‐binding shuttles and adaptors.
Collapse
Affiliation(s)
- Thuy P Dao
- Departments of Biology and Chemistry Syracuse University Syracuse NY USA
| | - Yiran Yang
- Department of Chemistry Syracuse University Syracuse NY USA
| | - Maria F Presti
- Department of Biochemistry and Molecular Biology SUNY Upstate Medical University Syracuse NY USA
| | - Michael S Cosgrove
- Department of Biochemistry and Molecular Biology SUNY Upstate Medical University Syracuse NY USA
| | - Jesse B Hopkins
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences Illinois Institute of Technology Chicago IL USA
| | - Weikang Ma
- The Biophysics Collaborative Access Team (BioCAT), Department of Biological Sciences Illinois Institute of Technology Chicago IL USA
| | - Stewart N Loh
- Department of Biochemistry and Molecular Biology SUNY Upstate Medical University Syracuse NY USA
| | - Carlos A Castañeda
- Departments of Biology and Chemistry Syracuse University Syracuse NY USA
- Interdisciplinary Neuroscience Program Syracuse University Syracuse NY USA
| |
Collapse
|
11
|
Cozzi M, Ferrari V. Autophagy Dysfunction in ALS: from Transport to Protein Degradation. J Mol Neurosci 2022; 72:1456-1481. [PMID: 35708843 PMCID: PMC9293831 DOI: 10.1007/s12031-022-02029-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/17/2022] [Indexed: 01/18/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting upper and lower motor neurons (MNs). Since the identification of the first ALS mutation in 1993, more than 40 genes have been associated with the disorder. The most frequent genetic causes of ALS are represented by mutated genes whose products challenge proteostasis, becoming unable to properly fold and consequently aggregating into inclusions that impose proteotoxic stress on affected cells. In this context, increasing evidence supports the central role played by autophagy dysfunctions in the pathogenesis of ALS. Indeed, in early stages of disease, high levels of proteins involved in autophagy are present in ALS MNs; but at the same time, with neurodegeneration progression, autophagy-mediated degradation decreases, often as a result of the accumulation of toxic protein aggregates in affected cells. Autophagy is a complex multistep pathway that has a central role in maintaining cellular homeostasis. Several proteins are involved in its tight regulation, and importantly a relevant fraction of ALS-related genes encodes products that directly take part in autophagy, further underlining the relevance of this key protein degradation system in disease onset and progression. In this review, we report the most relevant findings concerning ALS genes whose products are involved in the several steps of the autophagic pathway, from phagophore formation to autophagosome maturation and transport and finally to substrate degradation.
Collapse
Affiliation(s)
- Marta Cozzi
- Dipartimento Di Scienze Farmacologiche E Biomolecolari, Università Degli Studi Di Milano, 20133, Milan, Italy.
| | - Veronica Ferrari
- Dipartimento Di Scienze Farmacologiche E Biomolecolari, Università Degli Studi Di Milano, 20133, Milan, Italy.
| |
Collapse
|
12
|
The different autophagy degradation pathways and neurodegeneration. Neuron 2022; 110:935-966. [PMID: 35134347 PMCID: PMC8930707 DOI: 10.1016/j.neuron.2022.01.017] [Citation(s) in RCA: 152] [Impact Index Per Article: 76.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/31/2021] [Accepted: 01/11/2022] [Indexed: 12/11/2022]
Abstract
The term autophagy encompasses different pathways that route cytoplasmic material to lysosomes for degradation and includes macroautophagy, chaperone-mediated autophagy, and microautophagy. Since these pathways are crucial for degradation of aggregate-prone proteins and dysfunctional organelles such as mitochondria, they help to maintain cellular homeostasis. As post-mitotic neurons cannot dilute unwanted protein and organelle accumulation by cell division, the nervous system is particularly dependent on autophagic pathways. This dependence may be a vulnerability as people age and these processes become less effective in the brain. Here, we will review how the different autophagic pathways may protect against neurodegeneration, giving examples of both polygenic and monogenic diseases. We have considered how autophagy may have roles in normal CNS functions and the relationships between these degradative pathways and different types of programmed cell death. Finally, we will provide an overview of recently described strategies for upregulating autophagic pathways for therapeutic purposes.
Collapse
|
13
|
Todd TW, Petrucelli L. Modelling amyotrophic lateral sclerosis in rodents. Nat Rev Neurosci 2022; 23:231-251. [PMID: 35260846 DOI: 10.1038/s41583-022-00564-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2022] [Indexed: 12/11/2022]
Abstract
The efficient study of human disease requires the proper tools, one of the most crucial of which is an accurate animal model that faithfully recapitulates the human condition. The study of amyotrophic lateral sclerosis (ALS) is no exception. Although the majority of ALS cases are considered sporadic, most animal models of this disease rely on genetic mutations identified in familial cases. Over the past decade, the number of genes associated with ALS has risen dramatically and, with each new genetic variant, there is a drive to develop associated animal models. Rodent models are of particular importance as they allow for the study of ALS in the context of a living mammal with a comparable CNS. Such models not only help to verify the pathogenicity of novel mutations but also provide critical insight into disease mechanisms and are crucial for the testing of new therapeutics. In this Review, we aim to summarize the full spectrum of ALS rodent models developed to date.
Collapse
Affiliation(s)
- Tiffany W Todd
- Department of Neuroscience, Mayo Clinic Jacksonville, Jacksonville, FL, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic Jacksonville, Jacksonville, FL, USA.
| |
Collapse
|
14
|
Mohan HM, Trzeciakiewicz H, Pithadia A, Crowley EV, Pacitto R, Safren N, Trotter B, Zhang C, Zhou X, Zhang Y, Basrur V, Paulson HL, Sharkey LM. RTL8 promotes nuclear localization of UBQLN2 to subnuclear compartments associated with protein quality control. Cell Mol Life Sci 2022; 79:176. [PMID: 35247097 PMCID: PMC9376861 DOI: 10.1007/s00018-022-04170-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 01/17/2022] [Accepted: 01/25/2022] [Indexed: 11/24/2022]
Abstract
The brain-expressed ubiquilins (UBQLNs) 1, 2 and 4 are a family of ubiquitin adaptor proteins that participate broadly in protein quality control (PQC) pathways, including the ubiquitin proteasome system (UPS). One family member, UBQLN2, has been implicated in numerous neurodegenerative diseases including ALS/FTD. UBQLN2 typically resides in the cytoplasm but in disease can translocate to the nucleus, as in Huntington's disease where it promotes the clearance of mutant Huntingtin. How UBQLN2 translocates to the nucleus and clears aberrant nuclear proteins, however, is not well understood. In a mass spectrometry screen to discover UBQLN2 interactors, we identified a family of small (13 kDa), highly homologous uncharacterized proteins, RTL8, and confirmed the interaction between UBQLN2 and RTL8 both in vitro using recombinant proteins and in vivo using mouse brain tissue. Under endogenous and overexpressed conditions, RTL8 localizes to nucleoli. When co-expressed with UBQLN2, RTL8 promotes nuclear translocation of UBQLN2. RTL8 also facilitates UBQLN2's nuclear translocation during heat shock. UBQLN2 and RTL8 colocalize within ubiquitin-enriched subnuclear structures containing PQC components. The robust effect of RTL8 on the nuclear translocation and subnuclear localization of UBQLN2 does not extend to the other brain-expressed ubiquilins, UBQLN1 and UBQLN4. Moreover, compared to UBQLN1 and UBQLN4, UBQLN2 preferentially stabilizes RTL8 levels in human cell lines and in mouse brain, supporting functional heterogeneity among UBQLNs. As a novel UBQLN2 interactor that recruits UBQLN2 to specific nuclear compartments, RTL8 may regulate UBQLN2 function in nuclear protein quality control.
Collapse
Affiliation(s)
- Harihar Milaganur Mohan
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.,Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | | | - Amit Pithadia
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Emily V Crowley
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Regina Pacitto
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.,Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Bryce Trotter
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Chengxin Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Xiaogen Zhou
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Yang Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Venkatesha Basrur
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA. .,Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA. .,Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| |
Collapse
|
15
|
Deneubourg C, Ramm M, Smith LJ, Baron O, Singh K, Byrne SC, Duchen MR, Gautel M, Eskelinen EL, Fanto M, Jungbluth H. The spectrum of neurodevelopmental, neuromuscular and neurodegenerative disorders due to defective autophagy. Autophagy 2022; 18:496-517. [PMID: 34130600 PMCID: PMC9037555 DOI: 10.1080/15548627.2021.1943177] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 06/10/2021] [Indexed: 12/15/2022] Open
Abstract
Primary dysfunction of autophagy due to Mendelian defects affecting core components of the autophagy machinery or closely related proteins have recently emerged as an important cause of genetic disease. This novel group of human disorders may present throughout life and comprises severe early-onset neurodevelopmental and more common adult-onset neurodegenerative disorders. Early-onset (or congenital) disorders of autophagy often share a recognizable "clinical signature," including variable combinations of neurological, neuromuscular and multisystem manifestations. Structural CNS abnormalities, cerebellar involvement, spasticity and peripheral nerve pathology are prominent neurological features, indicating a specific vulnerability of certain neuronal populations to autophagic disturbance. A typically biphasic disease course of late-onset neurodegeneration occurring on the background of a neurodevelopmental disorder further supports a role of autophagy in both neuronal development and maintenance. Additionally, an associated myopathy has been characterized in several conditions. The differential diagnosis comprises a wide range of other multisystem disorders, including mitochondrial, glycogen and lysosomal storage disorders, as well as ciliopathies, glycosylation and vesicular trafficking defects. The clinical overlap between the congenital disorders of autophagy and these conditions reflects the multiple roles of the proteins and/or emerging molecular connections between the pathways implicated and suggests an exciting area for future research. Therapy development for congenital disorders of autophagy is still in its infancy but may result in the identification of molecules that target autophagy more specifically than currently available compounds. The close connection with adult-onset neurodegenerative disorders highlights the relevance of research into rare early-onset neurodevelopmental conditions for much more common, age-related human diseases.Abbreviations: AC: anterior commissure; AD: Alzheimer disease; ALR: autophagic lysosomal reformation; ALS: amyotrophic lateral sclerosis; AMBRA1: autophagy and beclin 1 regulator 1; AMPK: AMP-activated protein kinase; ASD: autism spectrum disorder; ATG: autophagy related; BIN1: bridging integrator 1; BPAN: beta-propeller protein associated neurodegeneration; CC: corpus callosum; CHMP2B: charged multivesicular body protein 2B; CHS: Chediak-Higashi syndrome; CMA: chaperone-mediated autophagy; CMT: Charcot-Marie-Tooth disease; CNM: centronuclear myopathy; CNS: central nervous system; DNM2: dynamin 2; DPR: dipeptide repeat protein; DVL3: disheveled segment polarity protein 3; EPG5: ectopic P-granules autophagy protein 5 homolog; ER: endoplasmic reticulum; ESCRT: homotypic fusion and protein sorting complex; FIG4: FIG4 phosphoinositide 5-phosphatase; FTD: frontotemporal dementia; GBA: glucocerebrosidase; GD: Gaucher disease; GRN: progranulin; GSD: glycogen storage disorder; HC: hippocampal commissure; HD: Huntington disease; HOPS: homotypic fusion and protein sorting complex; HSPP: hereditary spastic paraparesis; LAMP2A: lysosomal associated membrane protein 2A; MEAX: X-linked myopathy with excessive autophagy; mHTT: mutant huntingtin; MSS: Marinesco-Sjoegren syndrome; MTM1: myotubularin 1; MTOR: mechanistic target of rapamycin kinase; NBIA: neurodegeneration with brain iron accumulation; NCL: neuronal ceroid lipofuscinosis; NPC1: Niemann-Pick disease type 1; PD: Parkinson disease; PtdIns3P: phosphatidylinositol-3-phosphate; RAB3GAP1: RAB3 GTPase activating protein catalytic subunit 1; RAB3GAP2: RAB3 GTPase activating non-catalytic protein subunit 2; RB1: RB1-inducible coiled-coil protein 1; RHEB: ras homolog, mTORC1 binding; SCAR20: SNX14-related ataxia; SENDA: static encephalopathy of childhood with neurodegeneration in adulthood; SNX14: sorting nexin 14; SPG11: SPG11 vesicle trafficking associated, spatacsin; SQSTM1: sequestosome 1; TBC1D20: TBC1 domain family member 20; TECPR2: tectonin beta-propeller repeat containing 2; TSC1: TSC complex subunit 1; TSC2: TSC complex subunit 2; UBQLN2: ubiquilin 2; VCP: valosin-containing protein; VMA21: vacuolar ATPase assembly factor VMA21; WDFY3/ALFY: WD repeat and FYVE domain containing protein 3; WDR45: WD repeat domain 45; WDR47: WD repeat domain 47; WMS: Warburg Micro syndrome; XLMTM: X-linked myotubular myopathy; ZFYVE26: zinc finger FYVE-type containing 26.
Collapse
Affiliation(s)
- Celine Deneubourg
- Department of Basic and Clinical Neuroscience, IoPPN, King’s College London, London, UK
| | - Mauricio Ramm
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Luke J. Smith
- Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King’s College London, London, UK
| | - Olga Baron
- Wolfson Centre for Age-Related Diseases, King’s College London, London, UK
| | - Kritarth Singh
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Susan C. Byrne
- Department of Paediatric Neurology, Neuromuscular Service, Evelina’s Children Hospital, Guy’s & St. Thomas’ Hospital NHS Foundation Trust, London, UK
| | - Michael R. Duchen
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Mathias Gautel
- Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King’s College London, London, UK
| | - Eeva-Liisa Eskelinen
- Institute of Biomedicine, University of Turku, Turku, Finland
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Manolis Fanto
- Department of Basic and Clinical Neuroscience, IoPPN, King’s College London, London, UK
| | - Heinz Jungbluth
- Department of Basic and Clinical Neuroscience, IoPPN, King’s College London, London, UK
- Randall Division of Cell and Molecular Biophysics, Muscle Signalling Section, King’s College London, London, UK
- Department of Paediatric Neurology, Neuromuscular Service, Evelina’s Children Hospital, Guy’s & St. Thomas’ Hospital NHS Foundation Trust, London, UK
| |
Collapse
|
16
|
Verma S, Khurana S, Vats A, Sahu B, Ganguly NK, Chakraborti P, Gourie-Devi M, Taneja V. Neuromuscular Junction Dysfunction in Amyotrophic Lateral Sclerosis. Mol Neurobiol 2022; 59:1502-1527. [PMID: 34997540 DOI: 10.1007/s12035-021-02658-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/18/2021] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurological disorder characterized by progressive degeneration of motor neurons leading to skeletal muscle denervation. Earlier studies have shown that motor neuron degeneration begins in motor cortex and descends to the neuromuscular junction (NMJ) in a dying forward fashion. However, accumulating evidences support that ALS is a distal axonopathy where early pathological changes occur at the NMJ, prior to onset of clinical symptoms and propagates towards the motor neuron cell body supporting "dying back" hypothesis. Despite several evidences, series of events triggering NMJ disassembly in ALS are still obscure. Neuromuscular junction is a specialized tripartite chemical synapse which involves a well-coordinated communication among the presynaptic motor neuron, postsynaptic skeletal muscle, and terminal Schwann cells. This review provides comprehensive insight into the role of NMJ in ALS pathogenesis. We have emphasized the molecular alterations in cellular components of NMJ leading to loss of effective neuromuscular transmission in ALS. Further, we provide a preview into research involved in exploring NMJ as potential target for designing effective therapies for ALS.
Collapse
Affiliation(s)
- Sagar Verma
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.,Department of Biotechnology, Jamia Hamdard, Delhi, India
| | - Shiffali Khurana
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.,Department of Biomedical Science, Bhaskaracharya College of Applied Sciences, University of Delhi, Delhi, India
| | - Abhishek Vats
- Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bandana Sahu
- Department of Research, Sir Ganga Ram Hospital, Delhi, India
| | | | | | | | - Vibha Taneja
- Department of Research, Sir Ganga Ram Hospital, Delhi, India.
| |
Collapse
|
17
|
Hommen F, Bilican S, Vilchez D. Protein clearance strategies for disease intervention. J Neural Transm (Vienna) 2021; 129:141-172. [PMID: 34689261 PMCID: PMC8541819 DOI: 10.1007/s00702-021-02431-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 10/10/2021] [Indexed: 02/06/2023]
Abstract
Protein homeostasis, or proteostasis, is essential for cell function and viability. Unwanted, damaged, misfolded and aggregated proteins are degraded by the ubiquitin–proteasome system (UPS) and the autophagy-lysosome pathway. Growing evidence indicates that alterations in these major proteolytic mechanisms lead to a demise in proteostasis, contributing to the onset and development of distinct diseases. Indeed, dysregulation of the UPS or autophagy is linked to several neurodegenerative, infectious and inflammatory disorders as well as cancer. Thus, modulation of protein clearance pathways is a promising approach for therapeutics. In this review, we discuss recent findings and open questions on how targeting proteolytic mechanisms could be applied for disease intervention.
Collapse
Affiliation(s)
- Franziska Hommen
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph Stelzmann Strasse 26, 50931, Cologne, Germany
| | - Saygın Bilican
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph Stelzmann Strasse 26, 50931, Cologne, Germany
| | - David Vilchez
- Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph Stelzmann Strasse 26, 50931, Cologne, Germany. .,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany. .,Faculty of Medicine, University Hospital Cologne, Cologne, Germany.
| |
Collapse
|
18
|
Gerson JE, Safren N, Fischer S, Patel R, Crowley EV, Welday JP, Windle AK, Barmada S, Paulson HL, Sharkey LM. Ubiquilin-2 differentially regulates polyglutamine disease proteins. Hum Mol Genet 2021; 29:2596-2610. [PMID: 32681165 DOI: 10.1093/hmg/ddaa152] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 12/12/2022] Open
Abstract
Divergent protein context helps explain why polyglutamine expansion diseases differ clinically and pathologically. This heterogeneity may also extend to how polyglutamine disease proteins are handled by cellular pathways of proteostasis. Studies suggest, for example, that the ubiquitin-proteasome shuttle protein Ubiquilin-2 (UBQLN2) selectively interacts with specific polyglutamine disease proteins. Here we employ cellular models, primary neurons and mouse models to investigate the potential differential regulation by UBQLN2 of two polyglutamine disease proteins, huntingtin (HTT) and ataxin-3 (ATXN3). In cells, overexpressed UBQLN2 selectively lowered levels of full-length pathogenic HTT but not of HTT exon 1 fragment or full-length ATXN3. Consistent with these results, UBQLN2 specifically reduced accumulation of aggregated mutant HTT but not mutant ATXN3 in mouse models of Huntington's disease (HD) and spinocerebellar ataxia type 3 (SCA3), respectively. Normally a cytoplasmic protein, UBQLN2 translocated to the nuclei of neurons in HD mice but not in SCA3 mice. Remarkably, instead of reducing the accumulation of nuclear mutant ATXN3, UBQLN2 induced an accumulation of cytoplasmic ATXN3 aggregates in neurons of SCA3 mice. Together these results reveal a selective action of UBQLN2 toward polyglutamine disease proteins, indicating that polyglutamine expansion alone is insufficient to promote UBQLN2-mediated clearance of this class of disease proteins. Additional factors, including nuclear translocation of UBQLN2, may facilitate its action to clear intranuclear, aggregated disease proteins like HTT.
Collapse
Affiliation(s)
- Julia E Gerson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Svetlana Fischer
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Ronak Patel
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Emily V Crowley
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Jacqueline P Welday
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Alexandra K Windle
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Sami Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109-2200, USA
| |
Collapse
|
19
|
Li H, Wang F, Guo X, Jiang Y. Decreased MEF2A Expression Regulated by Its Enhancer Methylation Inhibits Autophagy and May Play an Important Role in the Progression of Alzheimer's Disease. Front Neurosci 2021; 15:682247. [PMID: 34220439 PMCID: PMC8242211 DOI: 10.3389/fnins.2021.682247] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 05/12/2021] [Indexed: 12/29/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease characterized by amyloid plaques and neurofibrillary tangles which significantly affects people's life quality. Recently, AD has been found to be closely related to autophagy. The aim of this study was to identify autophagy-related genes associated with the pathogenesis of AD from multiple types of microarray and sequencing datasets using bioinformatics methods and to investigate their role in the pathogenesis of AD in order to identify novel strategies to prevent and treat AD. Our results showed that the autophagy-related genes were significantly downregulated in AD and correlated with the pathological progression. Furthermore, enrichment analysis showed that these autophagy-related genes were regulated by the transcription factor myocyte enhancer factor 2A (MEF2A), which had been confirmed using si-MEF2A. Moreover, the single-cell sequencing data suggested that MEF2A was highly expressed in microglia. Methylation microarray analysis showed that the methylation level of the enhancer region of MEF2A in AD was significantly increased. In conclusion, our results suggest that AD related to the increased methylation level of MEF2A enhancer reduces the expression of MEF2A and downregulates the expression of autophagy-related genes which are closely associated with AD pathogenesis, thereby inhibiting autophagy.
Collapse
Affiliation(s)
- Hui Li
- Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Feng Wang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Xuqi Guo
- Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| | - Yugang Jiang
- Tianjin Institute of Environmental and Operational Medicine, Tianjin, China
| |
Collapse
|
20
|
Riley JF, Fioramonti PJ, Rusnock AK, Hehnly H, Castañeda CA. ALS-linked mutations impair UBQLN2 stress-induced biomolecular condensate assembly in cells. J Neurochem 2021; 159:145-155. [PMID: 34129687 DOI: 10.1111/jnc.15453] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 05/30/2021] [Accepted: 06/13/2021] [Indexed: 11/28/2022]
Abstract
Mutations in Ubiquilin-2 (UBQLN2), a ubiquitin-binding shuttle protein involved in several protein quality control processes, can lead to amyotrophic lateral sclerosis (ALS). We previously found that wild-type UBQLN2 forms dynamic, membraneless biomolecular condensates upon cellular stress, and undergoes liquid-liquid phase separation in vitro. However, the impact of ALS-linked mutations on UBQLN2 condensate formation in cells is unknown. Here, we employ live-cell imaging and photokinetic analysis to investigate how five patient-derived ALS-linked mutations in UBQLN2 impact stress-induced UBQLN2 condensate assembly and condensate material properties. Both wild-type and mutant UBQLN2 condensates are generally cytoplasmic and liquid-like. However, cells transfected with mutant UBQLN2 contain fewer stress-induced UBQLN2 condensates than those with wild-type UBQLN2. Most strikingly, exogenously expressed P506T UBQLN2 forms the lowest number of stress-induced condensates of all UBQLN2 mutants, and these condensates are significantly smaller than those of wild-type UBQLN2. Fluorescence recovery after photobleaching (FRAP) analysis of UBQLN2 condensates revealed higher immobile fractions for UBQLN2 mutants, especially P506T. P497S and P497H mutations differentially impact condensate properties, demonstrating that the effects of ALS-linked mutations are both position- and amino acid-dependent. Collectively, our data show that disease mutations hinder assembly and alter viscoelastic properties of stress-induced UBQLN2 condensates, potentially leading to aggregates commonly observed in ALS.
Collapse
Affiliation(s)
- Julia F Riley
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.,Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA.,Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY, 13244, USA
| | | | - Amber K Rusnock
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA
| | - Heidi Hehnly
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA
| | - Carlos A Castañeda
- Department of Biology, Syracuse University, Syracuse, NY, 13244, USA.,Department of Chemistry, Syracuse University, Syracuse, NY, 13244, USA.,Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY, 13244, USA
| |
Collapse
|
21
|
UBQLN2-HSP70 axis reduces poly-Gly-Ala aggregates and alleviates behavioral defects in the C9ORF72 animal model. Neuron 2021; 109:1949-1962.e6. [PMID: 33991504 DOI: 10.1016/j.neuron.2021.04.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 01/09/2021] [Accepted: 04/23/2021] [Indexed: 12/12/2022]
Abstract
Expansion of a hexanucleotide repeat GGGGCC (G4C2) in the intron of the C9ORF72 gene is the most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9-ALS/FTD). Transcripts carrying G4C2 repeat expansions generate neurotoxic dipeptide repeat (DPR) proteins, including poly-Gly-Ala (poly-GA), which tends to form protein aggregates. Here, we demonstrate that UBQLN2, another ALS/FTD risk factor, is recruited to reduce poly-GA aggregates and alleviate poly-GA-induced neurotoxicity. UBQLN2 could recognize HSP70 ubiquitination, which facilitates the UBQLN2-HSP70-GA complex formation and promotes poly-GA degradation. ALS/FTD-related UBQLN2 mutants fail to bind HSP70 and clear poly-GA aggregates. Disruption of the interaction between UBQLN2 and HSP70 inhibits poly-GA aggregation in C9-ALS/FTD iPSC-derived neurons. Finally, enhancing HSP70 by the chemical compound 17AAG at the adult stage mitigates behavioral defects in poly-GA animals. Our findings suggest a critical role of the UBQLN2-HSP70 axis in protein aggregate clearance in C9-ALS/FTD.
Collapse
|
22
|
Saxton AD, Kraemer BC. Human Ubiquilin 2 and TDP-43 co-pathology drives neurodegeneration in transgenic C. elegans. G3-GENES GENOMES GENETICS 2021; 11:6272515. [PMID: 33963840 DOI: 10.1093/g3journal/jkab158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 05/01/2021] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a debilitating, fatal neurodegenerative disease that causes rapid muscle wasting. It shares a spectrum of symptoms and pathology with frontotemporal lobar degeneration (FTLD). These diseases are caused by aberrant activity of a set of proteins including TDP-43 and UBIQUILIN-2 (UBQLN2). UBQLN2 encodes an ubiquitin-like adaptor protein involved in the ubiquitin-proteasome protein degradation pathway. Mutations in the PXX domain of UBQLN2 cause familial ALS. UBQLN2 aggregates in skein-like inclusions with other ALS and FTLD associated proteins including TDP-43 and ubiquitin. To facilitate further investigation of UBQLN2-mediated mechanisms of neurodegeneration, we made Caenorhabditis elegans transgenic lines pan-neuronally expressing human UBQLN2 cDNAs carrying either the wild-type UBQLN2 sequence or UBQLN2 with ALS causing mutations. Transgenic animals exhibit motor dysfunction accompanied by neurodegeneration of GABAergic motor neurons. At low levels of UBQLN2 expression, wild-type UBQLN2 causes significant motor impairment and neurodegeneration that is exacerbated by ALS associated mutations in UBQLN2. At higher levels of UBQLN2 expression, both wild-type and ALS mutated versions of UBQLN2 cause severe impairment. Molecular genetic investigation revealed that UBQLN2 dependent locomotor defects do not require the involvement of the endogenous homolog of TDP-43 in C. elegans (tdp-1). However, co-expression of wild-type human TDP-43 exacerbates UBQLN2 deficits. This model of UBQLN2-mediated neurodegeneration may be useful for further mechanistic investigation into the molecular cascades driving neurodegeneration in ALS and ALS-FTLD.
Collapse
Affiliation(s)
- Aleen D Saxton
- Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, 98108, United States of America
| | - Brian C Kraemer
- Geriatrics Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, Washington, 98108, United States of America; Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine, Seattle, WA 98104, USA; Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington 98195, USA; Department of Pathology, University of Washington School of Medicine, Seattle, Washington 98195, USA
| |
Collapse
|
23
|
Impaired 26S Proteasome Assembly Precedes Neuronal Loss in Mutant UBQLN2 Rats. Int J Mol Sci 2021; 22:ijms22094319. [PMID: 33919255 PMCID: PMC8122323 DOI: 10.3390/ijms22094319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 11/17/2022] Open
Abstract
Proteasomal dysfunction is known to be associated with amyotrophic lateral sclerosis and frontotemporal degeneration (ALS/FTD). Our previous reports have shown that a mutant form of ubiquilin-2 (UBQLN2) linked to ALS/FTD leads to neurodegeneration accompanied by accumulations of the proteasome subunit Rpt1 in transgenic rats, but the precise pathogenic mechanisms of how this mutation impairs the proteasome remains to be elucidated. Here, we reveal that this UBQLN2 mutation in rats disrupted the proteasome integrity prior to neurodegeneration, that it dissociated the 26S proteasome in vitro, and that its depletion did not affect 26S proteasome assembly. During both disease progression and in an age-dependent manner, we found that proteasome subunits were translocated to the nucleus, including both of the 20S core particles (PSMA1 and PSMB7) and the 19S regulatory particles (Rpt1 and Rpn1), suggesting that defective proteasome function may result from the proteasome-subunit mislocalization. Taken together, the present data demonstrate that impaired proteasome assembly is an early event in the pathogenesis of UBQLN2-associated neurodegeneration in mutant UBQLN2 rats.
Collapse
|
24
|
Gerson JE, Linton H, Xing J, Sutter AB, Kakos FS, Ryou J, Liggans N, Sharkey LM, Safren N, Paulson HL, Ivanova MI. Shared and divergent phase separation and aggregation properties of brain-expressed ubiquilins. Sci Rep 2021; 11:287. [PMID: 33431932 PMCID: PMC7801659 DOI: 10.1038/s41598-020-78775-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 11/25/2020] [Indexed: 01/29/2023] Open
Abstract
The brain-expressed ubiquilins, UBQLNs 1, 2 and 4, are highly homologous proteins that participate in multiple aspects of protein homeostasis and are implicated in neurodegenerative diseases. Studies have established that UBQLN2 forms liquid-like condensates and accumulates in pathogenic aggregates, much like other proteins linked to neurodegenerative diseases. However, the relative condensate and aggregate formation of the three brain-expressed ubiquilins is unknown. Here we report that the three ubiquilins differ in aggregation propensity, revealed by in-vitro experiments, cellular models, and analysis of human brain tissue. UBQLN4 displays heightened aggregation propensity over the other ubiquilins and, like amyloids, UBQLN4 forms ThioflavinT-positive fibrils in vitro. Measuring fluorescence recovery after photobleaching (FRAP) of puncta in cells, we report that all three ubiquilins undergo liquid-liquid phase transition. UBQLN2 and 4 exhibit slower recovery than UBQLN1, suggesting the condensates formed by these brain-expressed ubiquilins have different compositions and undergo distinct internal rearrangements. We conclude that while all brain-expressed ubiquilins exhibit self-association behavior manifesting as condensates, they follow distinct courses of phase-separation and aggregation. We suggest that this variability among ubiquilins along the continuum from liquid-like to solid informs both the normal ubiquitin-linked functions of ubiquilins and their accumulation and potential contribution to toxicity in neurodegenerative diseases.
Collapse
Affiliation(s)
- Julia E Gerson
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| | - Hunter Linton
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Jiazheng Xing
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Alexandra B Sutter
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
- Neuroscience Graduate Program, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Fayth S Kakos
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Jaimie Ryou
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Nyjerus Liggans
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Lisa M Sharkey
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
| | - Nathaniel Safren
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
| | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| | - Magdalena I Ivanova
- Department of Neurology, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
- Department of Neurology, Biophysics Program, University of Michigan, Ann Arbor, MI, 48109-2200, USA.
| |
Collapse
|
25
|
Zheng T, Yang Y, Castañeda CA. Structure, dynamics and functions of UBQLNs: at the crossroads of protein quality control machinery. Biochem J 2020; 477:3471-3497. [PMID: 32965492 PMCID: PMC7737201 DOI: 10.1042/bcj20190497] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/23/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022]
Abstract
Cells rely on protein homeostasis to maintain proper biological functions. Dysregulation of protein homeostasis contributes to the pathogenesis of many neurodegenerative diseases and cancers. Ubiquilins (UBQLNs) are versatile proteins that engage with many components of protein quality control (PQC) machinery in cells. Disease-linked mutations of UBQLNs are most commonly associated with amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and other neurodegenerative disorders. UBQLNs play well-established roles in PQC processes, including facilitating degradation of substrates through the ubiquitin-proteasome system (UPS), autophagy, and endoplasmic-reticulum-associated protein degradation (ERAD) pathways. In addition, UBQLNs engage with chaperones to sequester, degrade, or assist repair of misfolded client proteins. Furthermore, UBQLNs regulate DNA damage repair mechanisms, interact with RNA-binding proteins (RBPs), and engage with cytoskeletal elements to regulate cell differentiation and development. Important to the myriad functions of UBQLNs are its multidomain architecture and ability to self-associate. UBQLNs are linked to numerous types of cellular puncta, including stress-induced biomolecular condensates, autophagosomes, aggresomes, and aggregates. In this review, we focus on deciphering how UBQLNs function on a molecular level. We examine the properties of oligomerization-driven interactions among the structured and intrinsically disordered segments of UBQLNs. These interactions, together with the knowledge from studies of disease-linked mutations, provide significant insights to UBQLN structure, dynamics and function.
Collapse
Affiliation(s)
- Tongyin Zheng
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
| | - Yiran Yang
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
| | - Carlos A. Castañeda
- Department of Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
- Departments of Biology and Chemistry, Syracuse University, Syracuse, NY 13244, U.S.A
- Bioinspired Institute, and the Interdisciplinary Neuroscience Program, Syracuse University, Syracuse, NY 13244, U.S.A
| |
Collapse
|
26
|
Aydemir D, Ulusu NN. Importance of the serum biochemical parameters as potential biomarkers for rapid diagnosis and evaluating preclinical stage of ALS. Med Hypotheses 2020; 141:109736. [DOI: 10.1016/j.mehy.2020.109736] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/05/2020] [Accepted: 04/09/2020] [Indexed: 02/07/2023]
|
27
|
UBQLN2 Promotes the Production of Type I Interferon via the TBK1-IRF3 Pathway. Cells 2020; 9:cells9051205. [PMID: 32413959 PMCID: PMC7290724 DOI: 10.3390/cells9051205] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 12/13/2022] Open
Abstract
Mutations of Ubiquilin 2 (UBQLN2) or TANK-binding kinase 1 (TBK1) are associated with amyotrophic lateral sclerosis and frontotemporal degeneration (ALS/FTD). However, the mechanisms whereby UBQLN2 or TBK1 mutations lead to ALS and FTD remain unclear. Here, we explored the effect of UBQLN2 on TBK1 in HEK-293T cells or in CRISPR-Cas9-mediated IRF3 and IRF7 knockout (KO) cells. We found an interaction between TBK1 and UBQLN2, which was affected by ALS/FTD-linked mutations in TBK1 or UBQLN2. Co-expression of UBQLN2 with TBK1 elevated the protein level of TBK1 as well as the phosphorylation of TBK1 and IRF3 in a UBQLN2 dose-dependent manner, and this phosphorylation was reduced by mutant UBQLN2. In addition, the cellular production of IFN1 and related pro-inflammatory cytokines was substantially elevated when UBQLN2 and TBK1 were co-expressed, which was also decreased by mutant UBQLN2. Functional assay revealed that mutant UBQLN2 significantly reduced the binding affinity of TBK1 for its partners, including IRF3, (SQSTM1)/p62 and optineurin (OPTN). Moreover, complete loss of IRF3 abolished the induction of IFN1 and related pro-inflammatory cytokines enhanced by UBQLN2 in HEK-293T cells, whereas no significant change in IRF7 knockout cells was observed. Thus, our findings suggest that UBQLN2 promotes IRF3 phosphorylation via TBK1, leading to enhanced IFN1 induction, and also imply that the dysregulated TBK1-IRF3 pathway may play a role in UBQLN2-related neurodegeneration.
Collapse
|
28
|
Park H, Kang JH, Lee S. Autophagy in Neurodegenerative Diseases: A Hunter for Aggregates. Int J Mol Sci 2020; 21:ijms21093369. [PMID: 32397599 PMCID: PMC7247013 DOI: 10.3390/ijms21093369] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/07/2020] [Accepted: 05/07/2020] [Indexed: 12/14/2022] Open
Abstract
Cells have developed elaborate quality-control mechanisms for proteins and organelles to maintain cellular homeostasis. Such quality-control mechanisms are maintained by conformational folding via molecular chaperones and by degradation through the ubiquitin-proteasome or autophagy-lysosome system. Accumulating evidence suggests that impaired autophagy contributes to the accumulation of intracellular inclusion bodies consisting of misfolded proteins, which is a hallmark of most neurodegenerative diseases. In addition, genetic mutations in core autophagy-related genes have been reported to be linked to neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease. Conversely, the pathogenic proteins, such as amyloid β and α-synuclein, are detrimental to the autophagy pathway. Here, we review the recent advances in understanding the relationship between autophagic defects and the pathogenesis of neurodegenerative diseases and suggest autophagy induction as a promising strategy for the treatment of these conditions.
Collapse
Affiliation(s)
- Hyungsun Park
- Department of Anatomy, College of Medicine, Inha University, Incheon 22212, Korea;
- Hypoxia-related Disease Research Center, College of Medicine, Inha University, Incheon 22212, Korea;
| | - Ju-Hee Kang
- Hypoxia-related Disease Research Center, College of Medicine, Inha University, Incheon 22212, Korea;
- Department of Pharmacology, College of Medicine, Inha University, Incheon 22212, Korea
| | - Seongju Lee
- Department of Anatomy, College of Medicine, Inha University, Incheon 22212, Korea;
- Hypoxia-related Disease Research Center, College of Medicine, Inha University, Incheon 22212, Korea;
- Correspondence: ; Tel.: +82-32-860-9891
| |
Collapse
|
29
|
Stamatakou E, Wróbel L, Hill SM, Puri C, Son SM, Fujimaki M, Zhu Y, Siddiqi F, Fernandez-Estevez M, Manni MM, Park SJ, Villeneuve J, Rubinsztein DC. Mendelian neurodegenerative disease genes involved in autophagy. Cell Discov 2020; 6:24. [PMID: 32377374 PMCID: PMC7198619 DOI: 10.1038/s41421-020-0158-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/11/2020] [Indexed: 12/13/2022] Open
Abstract
The lysosomal degradation pathway of macroautophagy (herein referred to as autophagy) plays a crucial role in cellular physiology by regulating the removal of unwanted cargoes such as protein aggregates and damaged organelles. Over the last five decades, significant progress has been made in understanding the molecular mechanisms that regulate autophagy and its roles in human physiology and diseases. These advances, together with discoveries in human genetics linking autophagy-related gene mutations to specific diseases, provide a better understanding of the mechanisms by which autophagy-dependent pathways can be potentially targeted for treating human diseases. Here, we review mutations that have been identified in genes involved in autophagy and their associations with neurodegenerative diseases.
Collapse
Affiliation(s)
- Eleanna Stamatakou
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Lidia Wróbel
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Sandra Malmgren Hill
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Claudia Puri
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Sung Min Son
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Motoki Fujimaki
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Ye Zhu
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Farah Siddiqi
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Marian Fernandez-Estevez
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Marco M. Manni
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - So Jung Park
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - Julien Villeneuve
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| | - David Chaim Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, CB2 0XY UK
- UK Dementia Research Institute, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY UK
| |
Collapse
|
30
|
Autophagy in motor neuron diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 172:157-202. [PMID: 32620242 DOI: 10.1016/bs.pmbts.2020.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Motor neuron diseases (MNDs) are a wide group of neurodegenerative disorders characterized by the degeneration of a specific neuronal type located in the central nervous system, the motor neuron (MN). There are two main types of MNs, spinal and cortical MNs and depending on the type of MND, one or both types are affected. Cortical MNs innervate spinal MNs and these control a variety of cellular targets, being skeletal muscle their main one which is also affected in MNDs. A correct functionality of autophagy is necessary for the survival of all cellular types and it is particularly crucial for neurons, given their postmitotic and highly specialized nature. Numerous studies have identified alterations of autophagy activity in multiple MNDs. The scientific community has been particularly prolific in reporting the role that autophagy plays in the most common adult MND, amyotrophic lateral sclerosis, although many studies have started to identify physiological and pathological functions of this catabolic system in other MNDs, such as spinal muscular atrophy and spinal and bulbar muscular atrophy. The degradation of selective cargo by autophagy and how this process is altered upon the presence of MND-causing mutations is currently also a matter of intense investigation, particularly regarding the selective autophagic clearance of mitochondria. Thorough reviews on this field have been recently published. This chapter will cover the current knowledge on the functionality of autophagy and lysosomal homeostasis in the main MNDs and other autophagy-related topics in the MND field that have risen special interest in the research community.
Collapse
|
31
|
Vicencio E, Beltrán S, Labrador L, Manque P, Nassif M, Woehlbier U. Implications of Selective Autophagy Dysfunction for ALS Pathology. Cells 2020; 9:cells9020381. [PMID: 32046060 PMCID: PMC7072226 DOI: 10.3390/cells9020381] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disorder that progressively affects motor neurons in the brain and spinal cord. Due to the biological complexity of the disease, its etiology remains unknown. Several cellular mechanisms involved in the neurodegenerative process in ALS have been found, including the loss of RNA and protein homeostasis, as well as mitochondrial dysfunction. Insoluble protein aggregates, damaged mitochondria, and stress granules, which contain RNA and protein components, are recognized and degraded by the autophagy machinery in a process known as selective autophagy. Autophagy is a highly dynamic process whose dysregulation has now been associated with neurodegenerative diseases, including ALS, by numerous studies. In ALS, the autophagy process has been found deregulated in both familial and sporadic cases of the disease. Likewise, mutations in genes coding for proteins involved in the autophagy machinery have been reported in ALS patients, including selective autophagy receptors. In this review, we focus on the role of selective autophagy in ALS pathology.
Collapse
Affiliation(s)
- Emiliano Vicencio
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Sebastián Beltrán
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Luis Labrador
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Patricio Manque
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
| | - Melissa Nassif
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
- Correspondence: (U.W.); (M.N.)
| | - Ute Woehlbier
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
- Correspondence: (U.W.); (M.N.)
| |
Collapse
|
32
|
Abstract
In this issue of Structure, Dao et al. (2019) report that ALS-linked mutations in the Pxx domain of Ubiquilin 2 (UBQLN2) differentially influence the protein's phase separation abilities. The affect is by reducing the temperature and UBQLN2 concentration necessary for liquid-liquid phase separation droplet formation and by modulating UBQLN2 oligomerization.
Collapse
Affiliation(s)
- Nicole Higgins
- The Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Brian Lin
- The Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Mervyn J Monteiro
- The Center for Biomedical Engineering and Technology, Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| |
Collapse
|
33
|
Renaud L, Picher-Martel V, Codron P, Julien JP. Key role of UBQLN2 in pathogenesis of amyotrophic lateral sclerosis and frontotemporal dementia. Acta Neuropathol Commun 2019; 7:103. [PMID: 31319884 PMCID: PMC6889556 DOI: 10.1186/s40478-019-0758-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 06/22/2019] [Indexed: 12/11/2022] Open
Abstract
Ubiquilin-2 (UBQLN2) is a member of the ubiquilin family, actively implicated in the degradation of misfolded and redundant proteins through the ubiquitin-proteasome system and macroautophagy. UBQLN2 received much attention after the discovery of gene mutations in amyotrophic lateral sclerosis and frontotemporal dementia (ALS/FTD). The abnormal presence of positive UBQLN2 inclusion in the cytosol of degenerating motor neurons of familial and sporadic forms of ALS patients has been newly related to neurodegeneration. Only recently, data have emerged on its role in liquid-liquid phase separation, in stress granule development and in the formation of secondary amyloid structures. Furthermore, several animal models are available to investigate its involvement in TDP-43 pathology and neuroinflammation in ALS. This review addresses the molecular pathogenetic pathways involving UBQLN2 abnormalities which are converging toward defects in clearance mechanisms. UBQLN2.
Collapse
|
34
|
Vijayakumar UG, Milla V, Cynthia Stafford MY, Bjourson AJ, Duddy W, Duguez SMR. A Systematic Review of Suggested Molecular Strata, Biomarkers and Their Tissue Sources in ALS. Front Neurol 2019; 10:400. [PMID: 31139131 PMCID: PMC6527847 DOI: 10.3389/fneur.2019.00400] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 04/02/2019] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease, is an incurable neurodegenerative condition, characterized by the loss of upper and lower motor neurons. It affects 1–1.8/100,000 individuals worldwide, and the number of cases is projected to increase as the population ages. Thus, there is an urgent need to identify both therapeutic targets and disease-specific biomarkers–biomarkers that would be useful to diagnose and stratify patients into different sub-groups for therapeutic strategies, as well as biomarkers to follow the efficacy of any treatment tested during clinical trials. There is a lack of knowledge about pathogenesis and many hypotheses. Numerous “omics” studies have been conducted on ALS in the past decade to identify a disease-signature in tissues and circulating biomarkers. The first goal of the present review was to group the molecular pathways that have been implicated in monogenic forms of ALS, to enable the description of patient strata corresponding to each pathway grouping. This strategy allowed us to suggest 14 strata, each potentially targetable by different pharmacological strategies. The second goal of this review was to identify diagnostic/prognostic biomarker candidates consistently observed across the literature. For this purpose, we explore previous biomarker-relevant “omics” studies of ALS and summarize their findings, focusing on potential circulating biomarker candidates. We systematically review 118 papers on biomarkers published during the last decade. Several candidate markers were consistently shared across the results of different studies in either cerebrospinal fluid (CSF) or blood (leukocyte or serum/plasma). Although these candidates still need to be validated in a systematic manner, we suggest the use of combinations of biomarkers that would likely reflect the “health status” of different tissues, including motor neuron health (e.g., pNFH and NF-L, cystatin C, Transthyretin), inflammation status (e.g., MCP-1, miR451), muscle health (miR-338-3p, miR-206) and metabolism (homocysteine, glutamate, cholesterol). In light of these studies and because ALS is increasingly perceived as a multi-system disease, the identification of a panel of biomarkers that accurately reflect features of pathology is a priority, not only for diagnostic purposes but also for prognostic or predictive applications.
Collapse
Affiliation(s)
- Udaya Geetha Vijayakumar
- Northern Ireland Center for Stratified Medicine, Biomedical Sciences Research Institute, Londonderry, United Kingdom
| | - Vanessa Milla
- Northern Ireland Center for Stratified Medicine, Biomedical Sciences Research Institute, Londonderry, United Kingdom
| | - Mei Yu Cynthia Stafford
- Northern Ireland Center for Stratified Medicine, Biomedical Sciences Research Institute, Londonderry, United Kingdom
| | - Anthony J Bjourson
- Northern Ireland Center for Stratified Medicine, Biomedical Sciences Research Institute, Londonderry, United Kingdom
| | - William Duddy
- Northern Ireland Center for Stratified Medicine, Biomedical Sciences Research Institute, Londonderry, United Kingdom
| | - Stephanie Marie-Rose Duguez
- Northern Ireland Center for Stratified Medicine, Biomedical Sciences Research Institute, Londonderry, United Kingdom
| |
Collapse
|