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Jiang T, Ruan N, Luo P, Wang Q, Wei X, Li Y, Dai Y, Lin L, Lv J, Liu Y, Zhang C. Modulation of ER-mitochondria tethering complex VAPB-PTPIP51: Novel therapeutic targets for aging-associated diseases. Ageing Res Rev 2024; 98:102320. [PMID: 38719161 DOI: 10.1016/j.arr.2024.102320] [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: 10/04/2023] [Revised: 04/15/2024] [Accepted: 05/01/2024] [Indexed: 05/12/2024]
Abstract
Aging is a gradual and irreversible natural process. With aging, the body experiences a functional decline, and the effects amplify the vulnerability to a range of age-related diseases, including neurodegenerative, cardiovascular, and metabolic diseases. Within the aging process, the morphology and function of mitochondria and the endoplasmic reticulum (ER) undergo alterations, particularly in the structure connecting these organelles known as mitochondria-associated membranes (MAMs). MAMs serve as vital intracellular signaling hubs, facilitating communication between the ER and mitochondria when regulating various cellular events, including calcium homeostasis, lipid metabolism, mitochondrial function, and apoptosis. The formation of MAMs is partly dependent on the interaction between the vesicle-associated membrane protein-associated protein-B (VAPB) and protein tyrosine phosphatase-interacting protein-51 (PTPIP51). Accumulating evidence has begun to elucidate the pivotal role of the VAPB-PTPIP51 tether in the initiation and progression of age-related diseases. In this study, we delineate the intricate structure and multifunctional role of the VAPB-PTPIP51 tether and discuss its profound implications in aging-associated diseases. Moreover, we provide a comprehensive overview of potential therapeutic interventions and pharmacological agents targeting the VAPB-PTPIP51-mediated MAMs, thereby offering a glimmer of hope in mitigating aging processes and treating age-related disorders.
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Affiliation(s)
- Tao Jiang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Nan Ruan
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Pengcheng Luo
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qian Wang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiuxian Wei
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yi Li
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yue Dai
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Li Lin
- Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Division of Cardiology, Department of Internal Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jiagao Lv
- Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Division of Cardiology, Department of Internal Medicine, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yu Liu
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Cuntai Zhang
- Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Vascular Aging, Ministry of Education, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Kaur S, Sehrawat A, Mastana SS, Kandimalla R, Sharma PK, Bhatti GK, Bhatti JS. Targeting calcium homeostasis and impaired inter-organelle crosstalk as a potential therapeutic approach in Parkinson's disease. Life Sci 2023; 330:121995. [PMID: 37541578 DOI: 10.1016/j.lfs.2023.121995] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/06/2023]
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta, leading to motor symptoms such as tremors, rigidity, and bradykinesia. Current therapeutic strategies for PD are limited and mainly involve symptomatic relief, with no available treatment for the underlying causes of the disease. Therefore, there is a need for new therapeutic approaches that target the underlying pathophysiological mechanisms of PD. Calcium homeostasis is an essential process for maintaining proper cellular function and survival, including neuronal cells. Calcium dysregulation is also observed in various organelles, including the endoplasmic reticulum (ER), mitochondria, and lysosomes, resulting in organelle dysfunction and impaired inter-organelle communication. The ER, as the primary calcium reservoir, is responsible for folding proteins and maintaining calcium homeostasis, and its dysregulation can lead to protein misfolding and neurodegeneration. The crosstalk between ER and mitochondrial calcium signaling is disrupted in PD, leading to neuronal dysfunction and death. In addition, a lethal network of calcium cytotoxicity utilizes mitochondria, ER and lysosome to destroy neurons. This review article focused on the complex role of calcium dysregulation and its role in aggravating functioning of organelles in PD so as to provide new insight into therapeutic strategies for treating this disease. Targeting dysfunctional organelles, such as the ER and mitochondria and lysosomes and whole network of calcium dyshomeostasis can restore proper calcium homeostasis and improve neuronal function. Additionally targeting calcium dyshomeostasis that arises from miscommunication between several organelles can be targeted so that therapeutic effects of calcium are realised in whole cellular territory.
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Affiliation(s)
- Satinder Kaur
- Laboratory of Translational Medicine and Nanotherapeutics, Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda, India
| | - Abhishek Sehrawat
- Laboratory of Translational Medicine and Nanotherapeutics, Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda, India
| | - Sarabjit Singh Mastana
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
| | - Ramesh Kandimalla
- CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, Telangana, India
| | | | - Gurjit Kaur Bhatti
- Department of Medical Lab Technology, University Institute of Applied Health Sciences, Chandigarh University, Mohali, India.
| | - Jasvinder Singh Bhatti
- Laboratory of Translational Medicine and Nanotherapeutics, Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda, India.
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3
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Bernal AF, Mota N, Pamplona R, Area-Gomez E, Portero-Otin M. Hakuna MAM-Tata: Investigating the role of mitochondrial-associated membranes in ALS. Biochim Biophys Acta Mol Basis Dis 2023; 1869:166716. [PMID: 37044239 DOI: 10.1016/j.bbadis.2023.166716] [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: 03/15/2023] [Accepted: 04/03/2023] [Indexed: 04/14/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease leading to selective and progressive motor neuron (MN) death. Despite significant heterogeneity in pathogenic and clinical terms, MN demise ultimately unifies patients. Across the many disturbances in neuronal biology present in the disease and its models, two common trends are loss of calcium homeostasis and dysregulations in lipid metabolism. Since both mitochondria and endoplasmic reticulum (ER) are essential in these functions, their intertwin through the so-called mitochondrial-associated membranes (MAMs) should be relevant in this disease. In this review, we present a short overview of MAMs functional aspects and how its dysfunction could explain a substantial part of the cellular disarrangements in ALS's natural history. MAMs are hubs for lipid synthesis, integrating glycerophospholipids, sphingolipids, and cholesteryl ester metabolism. These lipids are essential for membrane biology, so there should be a close coupling to cellular energy demands, a role that MAMs may partially fulfill. Not surprisingly, MAMs are also host part of calcium signaling to mitochondria, so their impairment could lead to mitochondrial dysfunction, affecting oxidative phosphorylation and enhancing the vulnerability of MNs. We present data supporting that MAMs' maladaptation could be essential to MNs' vulnerability in ALS.
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Affiliation(s)
- Anna Fernàndez Bernal
- Metabolic Pathophysiology Research Group, Department of Experimental Medicine, University of Lleida-IRBLleida, Edifici Biomedicina I, Avda Rovira Roure 80, E25196 Lleida, Spain.
| | - Natàlia Mota
- Metabolic Pathophysiology Research Group, Department of Experimental Medicine, University of Lleida-IRBLleida, Edifici Biomedicina I, Avda Rovira Roure 80, E25196 Lleida, Spain.
| | - Reinald Pamplona
- Metabolic Pathophysiology Research Group, Department of Experimental Medicine, University of Lleida-IRBLleida, Edifici Biomedicina I, Avda Rovira Roure 80, E25196 Lleida, Spain.
| | - Estela Area-Gomez
- Centro de Investigaciones Biológicas Margarita Salas CSIC, C. Ramiro de Maeztu, 9, 28040 Madrid, Spain.
| | - Manuel Portero-Otin
- Metabolic Pathophysiology Research Group, Department of Experimental Medicine, University of Lleida-IRBLleida, Edifici Biomedicina I, Avda Rovira Roure 80, E25196 Lleida, Spain.
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Hu Z, Shi S, Ou Y, Hu F, Long D. Mitochondria-associated endoplasmic reticulum membranes: A promising toxicity regulation target. Acta Histochem 2023; 125:152000. [PMID: 36696877 DOI: 10.1016/j.acthis.2023.152000] [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: 11/30/2022] [Revised: 01/15/2023] [Accepted: 01/16/2023] [Indexed: 01/24/2023]
Abstract
Mitochondria-associated endoplasmic reticulum membranes (MAMs) are dynamic suborganelle membranes that physically couple endoplasmic reticulum (ER) and mitochondria to provide a platform for exchange of intracellular molecules and crosstalk between the two organelles. Dysfunctions of mitochondria and ER and imbalance of intracellular homeostasis have been discovered in the research of toxics. Cellular activities such as oxidative stress, ER stress, Ca2+ transport, autophagy, mitochondrial fusion and fission, and apoptosis mediated by MAMs are closely related to the toxicological effects of various toxicants. These cellular activities mediated by MAMs crosstalk with each other. Regulating the structure and function of MAMs can alleviate the damage caused by toxicants to some extent. In this review, we discuss the relationships between MAMs and the mechanisms of toxicological effects, and highlight MAMs as a potential target for protection against toxicants.
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Affiliation(s)
- Zehui Hu
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Shengyuan Shi
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Yiquan Ou
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Fangyan Hu
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China
| | - Dingxin Long
- Hunan Province Key Laboratory of Typical Environmental Pollution and Health Hazards, School of Public Health, Hengyang Medical School, University of South China, Hengyang 421001, PR China.
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Wenzel EM, Elfmark LA, Stenmark H, Raiborg C. ER as master regulator of membrane trafficking and organelle function. J Cell Biol 2022; 221:213468. [PMID: 36108241 PMCID: PMC9481738 DOI: 10.1083/jcb.202205135] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 08/16/2022] [Accepted: 08/22/2022] [Indexed: 12/13/2022] Open
Abstract
The endoplasmic reticulum (ER), which occupies a large portion of the cytoplasm, is the cell’s main site for the biosynthesis of lipids and carbohydrate conjugates, and it is essential for folding, assembly, and biosynthetic transport of secreted proteins and integral membrane proteins. The discovery of abundant membrane contact sites (MCSs) between the ER and other membrane compartments has revealed that, in addition to its biosynthetic and secretory functions, the ER plays key roles in the regulation of organelle dynamics and functions. In this review, we will discuss how the ER regulates endosomes, lysosomes, autophagosomes, mitochondria, peroxisomes, and the Golgi apparatus via MCSs. Such regulation occurs via lipid and Ca2+ transfer and also via control of in trans dephosphorylation reactions and organelle motility, positioning, fusion, and fission. The diverse controls of other organelles via MCSs manifest the ER as master regulator of organelle biology.
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Affiliation(s)
- Eva Maria Wenzel
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway 1
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway 2
| | - Liv Anker Elfmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway 1
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway 2
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway 1
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway 2
| | - Camilla Raiborg
- Centre for Cancer Cell Reprogramming, Faculty of Medicine, University of Oslo, Oslo, Norway 1
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway 2
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de Mena L, Lopez-Scarim J, Rincon-Limas DE. TDP-43 and ER Stress in Neurodegeneration: Friends or Foes? Front Mol Neurosci 2021; 14:772226. [PMID: 34759799 PMCID: PMC8573113 DOI: 10.3389/fnmol.2021.772226] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 09/30/2021] [Indexed: 02/05/2023] Open
Abstract
Nuclear depletion, abnormal modification, and cytoplasmic aggregation of TAR DNA-binding protein 43 (TDP-43) are linked to a group of fatal neurodegenerative diseases called TDP-43 proteinopathies, which include amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Although our understanding of the physiological function of TDP-43 is rapidly advancing, the molecular mechanisms associated with its pathogenesis remain poorly understood. Accumulating evidence suggests that endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) are important players in TDP-43 pathology. However, while neurons derived from autopsied ALS and FTLD patients revealed TDP-43 deposits in the ER and displayed UPR activation, data originated from in vitro and in vivo TDP-43 models produced contradictory results. In this review, we will explore the complex interplay between TDP-43 pathology, ER stress, and the UPR by breaking down the evidence available in the literature and addressing the reasons behind these discrepancies. We also highlight underexplored areas and key unanswered questions in the field. A better synchronization and integration of methodologies, models, and mechanistic pathways will be crucial to discover the true nature of the TDP-43 and ER stress relationship and, ultimately, to uncover the full therapeutic potential of the UPR.
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Affiliation(s)
- Lorena de Mena
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Joshua Lopez-Scarim
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States
| | - Diego E Rincon-Limas
- Department of Neurology, McKnight Brain Institute, and Norman Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States.,Department of Neuroscience, Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States.,Genetics Institute, University of Florida, Gainesville, FL, United States
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7
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Peggion C, Massimino ML, Bonadio RS, Lia F, Lopreiato R, Cagnin S, Calì T, Bertoli A. Regulation of Endoplasmic Reticulum-Mitochondria Tethering and Ca 2+ Fluxes by TDP-43 via GSK3β. Int J Mol Sci 2021; 22:11853. [PMID: 34769284 PMCID: PMC8584823 DOI: 10.3390/ijms222111853] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 12/13/2022] Open
Abstract
Mitochondria-ER contacts (MERCs), tightly regulated by numerous tethering proteins that act as molecular and functional connections between the two organelles, are essential to maintain a variety of cellular functions. Such contacts are often compromised in the early stages of many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS). TDP-43, a nuclear protein mainly involved in RNA metabolism, has been repeatedly associated with ALS pathogenesis and other neurodegenerative diseases. Although TDP-43 neuropathological mechanisms are still unclear, the accumulation of the protein in cytoplasmic inclusions may underlie a protein loss-of-function effect. Accordingly, we investigated the impact of siRNA-mediated TDP-43 silencing on MERCs and the related cellular parameters in HeLa cells using GFP-based probes for MERCs quantification and aequorin-based probes for local Ca2+ measurements, combined with targeted protein and mRNA profiling. Our results demonstrated that TDP-43 down-regulation decreases MERCs density, thereby remarkably reducing mitochondria Ca2+ uptake after ER Ca2+ release. Thorough mRNA and protein analyses did not highlight altered expression of proteins involved in MERCs assembly or Ca2+-mediated ER-mitochondria cross-talk, nor alterations of mitochondrial density and morphology were observed by confocal microscopy. Further mechanistic inspections, however, suggested that the observed cellular alterations are correlated to increased expression/activity of GSK3β, previously associated with MERCs disruption.
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Affiliation(s)
- Caterina Peggion
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy; (F.L.); (R.L.); (T.C.)
| | | | - Raphael Severino Bonadio
- Department of Biology, CRIBI Biotechnology Center, University of Padova, 35131 Padova, Italy; (R.S.B.); (S.C.)
| | - Federica Lia
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy; (F.L.); (R.L.); (T.C.)
| | - Raffaele Lopreiato
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy; (F.L.); (R.L.); (T.C.)
| | - Stefano Cagnin
- Department of Biology, CRIBI Biotechnology Center, University of Padova, 35131 Padova, Italy; (R.S.B.); (S.C.)
- CIR-Myo Myology Center, University of Padova, 35131 Padova, Italy
| | - Tito Calì
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy; (F.L.); (R.L.); (T.C.)
- Padova Neuroscience Center, University of Padova, 35131 Padova, Italy
| | - Alessandro Bertoli
- Department of Biomedical Sciences, University of Padova, 35131 Padova, Italy; (F.L.); (R.L.); (T.C.)
- CNR—Neuroscience Institute, 35131 Padova, Italy;
- Padova Neuroscience Center, University of Padova, 35131 Padova, Italy
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8
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Borgese N, Navone F, Nukina N, Yamanaka T. Mutant VAPB: Culprit or Innocent Bystander of Amyotrophic Lateral Sclerosis? CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2021; 4:25152564211022515. [PMID: 37366377 PMCID: PMC10243577 DOI: 10.1177/25152564211022515] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/08/2021] [Accepted: 05/12/2021] [Indexed: 06/28/2023]
Abstract
Nearly twenty years ago a mutation in the VAPB gene, resulting in a proline to serine substitution (p.P56S), was identified as the cause of a rare, slowly progressing, familial form of the motor neuron degenerative disease Amyotrophic Lateral Sclerosis (ALS). Since then, progress in unravelling the mechanistic basis of this mutation has proceeded in parallel with research on the VAP proteins and on their role in establishing membrane contact sites between the ER and other organelles. Analysis of the literature on cellular and animal models reviewed here supports the conclusion that P56S-VAPB, which is aggregation-prone, non-functional and unstable, is expressed at levels that are insufficient to support toxic gain-of-function or dominant negative effects within motor neurons. Instead, insufficient levels of the product of the single wild-type allele appear to be required for pathological effects, and may be the main driver of the disease. In light of the multiple interactions of the VAP proteins, we address the consequences of specific VAPB depletion and highlight various affected processes that could contribute to motor neuron degeneration. In the future, distinction of specific roles of each of the two VAP paralogues should help to further elucidate the basis of p.P56S familial ALS, as well as of other more common forms of the disease.
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Affiliation(s)
- Nica Borgese
- CNR Institute of
Neuroscience, Vedano al Lambro (MB), Italy
| | | | - Nobuyuki Nukina
- Laboratory of Structural
Neuropathology, Doshisha University Graduate School of Brain Science,
Kyoto, Japan
| | - Tomoyuki Yamanaka
- Laboratory of Structural
Neuropathology, Doshisha University Graduate School of Brain Science,
Kyoto, Japan
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9
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Shirokova OM, Pchelin PV, Mukhina IV. MERCs. The Novel Assistant to Neurotransmission? Front Neurosci 2020; 14:589319. [PMID: 33240039 PMCID: PMC7680918 DOI: 10.3389/fnins.2020.589319] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/19/2020] [Indexed: 12/11/2022] Open
Abstract
In neuroscience, much attention is paid to intercellular interactions, in particular, to synapses. However, many researchers do not pay due attention to the contribution of intracellular contacts to the work of intercellular interactions. Nevertheless, along with synapses, intracellular contacts also have complex organization and a tremendous number of regulatory elements. Mitochondria-endoplasmic reticulum contacts (MERCs) are a specific site of interaction between the two organelles; they provide a basis for a large number of cellular functions, such as calcium homeostasis, lipid metabolism, autophagy, and apoptosis. Despite the presence of these contacts in various parts of neurons and glial cells, it is yet not known whether they fulfill the same functions. There are still many unsolved questions about the work of these intracellular contacts, and one of the most important among them is if MERCs, with their broad implication into synaptic events, can be considered the assistant to neurotransmission?
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Affiliation(s)
- Olesya M Shirokova
- Central Scientific Research Laboratory, Institute of Fundamental Medicine, Privolzhsky Research Medical University, Nizhny Novgorod, Russia
| | - Pavel V Pchelin
- Central Scientific Research Laboratory, Institute of Fundamental Medicine, Privolzhsky Research Medical University, Nizhny Novgorod, Russia.,Department of Neurotechnology, Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Irina V Mukhina
- Central Scientific Research Laboratory, Institute of Fundamental Medicine, Privolzhsky Research Medical University, Nizhny Novgorod, Russia.,Department of Neurotechnology, Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
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10
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Rps27a might act as a controller of microglia activation in triggering neurodegenerative diseases. PLoS One 2020; 15:e0239219. [PMID: 32941527 PMCID: PMC7498011 DOI: 10.1371/journal.pone.0239219] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 09/01/2020] [Indexed: 01/10/2023] Open
Abstract
Neurodegenerative diseases (NDDs) are increasing serious menaces to human health in the recent years. Despite exhibiting different clinical phenotypes and selective neuronal loss, there are certain common features in these disorders, suggesting the presence of commonly dysregulated pathways. Identifying causal genes and dysregulated pathways can be helpful in providing effective treatment in these diseases. Interestingly, in spite of the considerable researches on NDDs, to the best of our knowledge, no dysregulated genes and/or pathways were reported in common across all the major NDDs so far. In this study, for the first time, we have applied the three-way interaction model, as an approach to unravel sophisticated gene interactions, to trace switch genes and significant pathways that are involved in six major NDDs. Subsequently, a gene regulatory network was constructed to investigate the regulatory communication of statistically significant triplets. Finally, KEGG pathway enrichment analysis was applied to find possible common pathways. Because of the central role of neuroinflammation and immune system responses in both pathogenic and protective mechanisms in the NDDs, we focused on immune genes in this study. Our results suggest that "cytokine-cytokine receptor interaction" pathway is enriched in all of the studied NDDs, while "osteoclast differentiation" and "natural killer cell mediated cytotoxicity" pathways are enriched in five of the NDDs each. The results of this study indicate that three pathways that include "osteoclast differentiation", "natural killer cell mediated cytotoxicity" and "cytokine-cytokine receptor interaction" are common in five, five and six NDDs, respectively. Additionally, our analysis showed that Rps27a as a switch gene, together with the gene pair {Il-18, Cx3cl1} form a statistically significant and biologically relevant triplet in the major NDDs. More specifically, we suggested that Cx3cl1 might act as a potential upstream regulator of Il-18 in microglia activation, and in turn, might be controlled with Rps27a in triggering NDDs.
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11
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Mijanović O, Branković A, Borovjagin AV, Butnaru DV, Bezrukov EA, Sukhanov RB, Shpichka A, Timashev P, Ulasov I. Battling Neurodegenerative Diseases with Adeno-Associated Virus-Based Approaches. Viruses 2020; 12:v12040460. [PMID: 32325732 PMCID: PMC7232215 DOI: 10.3390/v12040460] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/06/2020] [Accepted: 04/15/2020] [Indexed: 02/06/2023] Open
Abstract
Neurodegenerative diseases (NDDs) are most commonly found in adults and remain essentially incurable. Gene therapy using AAV vectors is a rapidly-growing field of experimental medicine that holds promise for the treatment of NDDs. To date, effective delivery of a therapeutic gene into target cells via AAV has been a major obstacle in the field. Ideally, transgenes should be delivered into the target cells specifically and efficiently, while promiscuous or off-target gene delivery should be minimized to avoid toxicity. In the pursuit of an ideal vehicle for NDD gene therapy, a broad variety of vector systems have been explored. Here we specifically outline the advantages of adeno-associated virus (AAV)-based vector systems for NDD therapy application. In contrast to many reviews on NDDs that can be found in the literature, this review is rather focused on AAV vector selection and their testing in experimental and preclinical NDD models. Preclinical and in vitro data reveal the strong potential of AAV for NDD-related diagnostics and therapeutic strategies.
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Affiliation(s)
- Olja Mijanović
- Group of Experimental Biotherapy and Diagnostics, Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Moscow 119991, Russia;
| | - Ana Branković
- Department of Forensics, University of Criminal Investigation and Police Studies, Belgrade 11000, Serbia;
| | - Anton V. Borovjagin
- Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, AL 35294, USA;
| | - Denis V. Butnaru
- Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Moscow 119991, Russia; (D.V.B.); (A.S.); (P.T.)
| | - Evgeny A. Bezrukov
- Institute for Uronephrology and Reproductive Health, Sechenov First Moscow State Medical University, Moscow 119991, Russia; (E.A.B.); (R.B.S.)
| | - Roman B. Sukhanov
- Institute for Uronephrology and Reproductive Health, Sechenov First Moscow State Medical University, Moscow 119991, Russia; (E.A.B.); (R.B.S.)
| | - Anastasia Shpichka
- Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Moscow 119991, Russia; (D.V.B.); (A.S.); (P.T.)
| | - Peter Timashev
- Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Moscow 119991, Russia; (D.V.B.); (A.S.); (P.T.)
- Institute of Photonic Technologies, Research Center “Crystallography and Photonics”, Russian Academy of Sciences, Troitsk, Moscow 142190, Russia
- Department of Polymers and Composites, N.N. Semenov Institute of Chemical Physics, Moscow 119991, Russia
- Chemistry Department, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Ilya Ulasov
- Group of Experimental Biotherapy and Diagnostics, Institute for Regenerative Medicine, Sechenov First Moscow State Medical University, Moscow 119991, Russia;
- Correspondence:
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12
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Vallese F, Barazzuol L, Maso L, Brini M, Calì T. ER-Mitochondria Calcium Transfer, Organelle Contacts and Neurodegenerative Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1131:719-746. [PMID: 31646532 DOI: 10.1007/978-3-030-12457-1_29] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
It is generally accepted that interorganellar contacts are central to the control of cellular physiology. Virtually, any intracellular organelle can come into proximity with each other and, by establishing physical protein-mediated contacts within a selected fraction of the membrane surface, novel specific functions are acquired. Endoplasmic reticulum (ER) contacts with mitochondria are among the best studied and have a major role in Ca2+ and lipid transfer, signaling, and membrane dynamics.Their functional (and structural) diversity, their dynamic nature as well as the growing number of new players involved in the tethering concurred to make their monitoring difficult especially in living cells. This review focuses on the most established examples of tethers/modulators of the ER-mitochondria interface and on the roles of these contacts in health and disease by specifically dissecting how Ca2+ transfer occurs and how mishandling eventually leads to disease. Additional functions of the ER-mitochondria interface and an overview of the currently available methods to measure/quantify the ER-mitochondria interface will also be discussed.
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Affiliation(s)
- Francesca Vallese
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Lorenzo Maso
- Department of Biology, University of Padua, Padua, Italy
| | - Marisa Brini
- Department of Biology, University of Padua, Padua, Italy.
| | - Tito Calì
- Department of Biomedical Sciences, University of Padua, Padua, Italy. .,Padua Neuroscience Center (PNC), Padua, Italy.
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13
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Altered interplay between endoplasmic reticulum and mitochondria in Charcot-Marie-Tooth type 2A neuropathy. Proc Natl Acad Sci U S A 2019; 116:2328-2337. [PMID: 30659145 DOI: 10.1073/pnas.1810932116] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mutations in the MFN2 gene encoding Mitofusin 2 lead to the development of Charcot-Marie-Tooth type 2A (CMT2A), a dominant axonal form of peripheral neuropathy. Mitofusin 2 is localized at both the outer membrane of mitochondria and the endoplasmic reticulum and is particularly enriched at specialized contact regions known as mitochondria-associated membranes (MAM). We observed that expression of MFN2R94Q induces distal axonal degeneration in the absence of overt neuronal death. The presence of mutant protein leads to reduction in endoplasmic reticulum and mitochondria contacts in CMT2A patient-derived fibroblasts, in primary neurons and in vivo, in motoneurons of a mouse model of CMT2A. These changes are concomitant with endoplasmic reticulum stress, calcium handling defects, and changes in the geometry and axonal transport of mitochondria. Importantly, pharmacological treatments reinforcing endoplasmic reticulum-mitochondria cross-talk, or reducing endoplasmic reticulum stress, restore the mitochondria morphology and prevent axonal degeneration. These results highlight defects in MAM as a cellular mechanism contributing to CMT2A pathology mediated by mutated MFN2.
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14
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Endoplasmic reticulum and mitochondria in diseases of motor and sensory neurons: a broken relationship? Cell Death Dis 2018; 9:333. [PMID: 29491369 PMCID: PMC5832431 DOI: 10.1038/s41419-017-0125-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Revised: 09/25/2017] [Accepted: 10/10/2017] [Indexed: 12/13/2022]
Abstract
Recent progress in the understanding of neurodegenerative diseases revealed that multiple molecular mechanisms contribute to pathological changes in neurons. A large fraction of these alterations can be linked to dysfunction in the endoplasmic reticulum (ER) and mitochondria, affecting metabolism and secretion of lipids and proteins, calcium homeostasis, and energy production. Remarkably, these organelles are interacting with each other at specialized domains on the ER called mitochondria-associated membranes (MAMs). These membrane structures rely on the interaction of several complexes of proteins localized either at the mitochondria or at the ER interface and serve as an exchange platform of calcium, metabolites, and lipids, which are critical for the function of both organelles. In addition, recent evidence indicates that MAMs also play a role in the control of mitochondria dynamics and autophagy. MAMs thus start to emerge as a key element connecting many changes observed in neurodegenerative diseases. This review will focus on the role of MAMs in amyotrophic lateral sclerosis (ALS) and hereditary motor and sensory neuropathy, two neurodegenerative diseases particularly affecting neurons with long projecting axons. We will discuss how defects in MAM signaling may impair neuronal calcium homeostasis, mitochondrial dynamics, ER function, and autophagy, leading eventually to axonal degeneration. The possible impact of MAM dysfunction in glial cells, which may affect the capacity to support neurons and/or axons, will also be described. Finally, the possible role of MAMs as an interesting target for development of therapeutic interventions aiming at delaying or preventing neurodegeneration will be highlighted.
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15
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Kim JY, Jang A, Reddy R, Yoon WH, Jankowsky JL. Neuronal overexpression of human VAPB slows motor impairment and neuromuscular denervation in a mouse model of ALS. Hum Mol Genet 2018; 25:4661-4673. [PMID: 28173107 DOI: 10.1093/hmg/ddw294] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 08/21/2016] [Accepted: 08/25/2016] [Indexed: 02/07/2023] Open
Abstract
Four mutations in the VAMP/synaptobrevin-associated protein B (VAPB) gene have been linked to amyotrophic lateral sclerosis (ALS) type 8. The mechanism by which VAPB mutations cause motor neuron disease is unclear, but studies of the most common P56S variant suggest both loss of function and dominant-negative sequestration of wild-type protein. Diminished levels of VAPB and its proteolytic cleavage fragment have also been reported in sporadic ALS cases, suggesting that VAPB loss of function may be a common mechanism of disease. Here, we tested whether neuronal overexpression of wild-type human VAPB would attenuate disease in a mouse model of familial ALS1. We used neonatal intraventricular viral injections to express VAPB or YFP throughout the brain and spinal cord of superoxide dismutase (SOD1) G93A transgenic mice. Lifelong elevation of neuronal VAPB slowed the decline of neurological impairment, delayed denervation of hindlimb muscles, and prolonged survival of spinal motor neurons. Collectively, these changes produced a slight but significant extension in lifespan, even in this highly aggressive model of disease. Our findings lend support for a protective role of VAPB in neuromuscular health.
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Affiliation(s)
- Ji-Yoen Kim
- Department of Neuroscience, Baylor College of Medicine, Houston, TX , USA
| | - Ava Jang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX , USA.,Department of Psychology, Baylor College of Medicine, Houston, TX , USA
| | - Rohit Reddy
- Department of Neuroscience, Baylor College of Medicine, Houston, TX , USA.,Department of Cognitive Science, Rice University, Houston, TX, USA
| | - Wan Hee Yoon
- Howard Hughes Medical Institute,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Joanna L Jankowsky
- Department of Neuroscience, Baylor College of Medicine, Houston, TX , USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
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16
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Maurel C, Dangoumau A, Marouillat S, Brulard C, Chami A, Hergesheimer R, Corcia P, Blasco H, Andres CR, Vourc'h P. Causative Genes in Amyotrophic Lateral Sclerosis and Protein Degradation Pathways: a Link to Neurodegeneration. Mol Neurobiol 2018; 55:6480-6499. [PMID: 29322304 DOI: 10.1007/s12035-017-0856-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 12/20/2017] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease caused by the degeneration of motor neurons (MNs) leading to progressive muscle weakness and atrophy. Several molecular pathways have been implicated, such as glutamate-mediated excitotoxicity, defects in cytoskeletal dynamics and axonal transport, disruption of RNA metabolism, and impairments in proteostasis. ALS is associated with protein accumulation in the cytoplasm of cells undergoing neurodegeneration, which is a hallmark of the disease. In this review, we focus on mechanisms of proteostasis, particularly protein degradation, and discuss how they are related to the genetics of ALS. Indeed, the genetic bases of the disease with the implication of more than 30 genes associated with familial ALS to date, together with the important increase in understanding of endoplasmic reticulum (ER) stress, proteasomal degradation, and autophagy, allow researchers to better understand the mechanisms underlying the selective death of motor neurons in ALS. It is clear that defects in proteostasis are involved in this type of cellular degeneration, but whether or not these mechanisms are primary causes or merely consequential remains to be clearly demonstrated. Novel cellular and animal models allowing chronic expression of mutant proteins, for example, are required. Further studies linking genetic discoveries in ALS to mechanisms of protein clearance will certainly be crucial in order to accelerate translational and clinical research towards new therapeutic targets and strategies.
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Affiliation(s)
- C Maurel
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Dangoumau
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - S Marouillat
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - C Brulard
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Chami
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - R Hergesheimer
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - P Corcia
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Neurologie, CHRU de Tours, 37044, Tours, France
| | - H Blasco
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - C R Andres
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - P Vourc'h
- UMR INSERM U1253, Université de Tours, 37032, Tours, France.
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France.
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17
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Shahheydari H, Ragagnin A, Walker AK, Toth RP, Vidal M, Jagaraj CJ, Perri ER, Konopka A, Sultana JM, Atkin JD. Protein Quality Control and the Amyotrophic Lateral Sclerosis/Frontotemporal Dementia Continuum. Front Mol Neurosci 2017; 10:119. [PMID: 28539871 PMCID: PMC5423993 DOI: 10.3389/fnmol.2017.00119] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis, or proteostasis, has an important regulatory role in cellular function. Protein quality control mechanisms, including protein folding and protein degradation processes, have a crucial function in post-mitotic neurons. Cellular protein quality control relies on multiple strategies, including molecular chaperones, autophagy, the ubiquitin proteasome system, endoplasmic reticulum (ER)-associated degradation (ERAD) and the formation of stress granules (SGs), to regulate proteostasis. Neurodegenerative diseases are characterized by the presence of misfolded protein aggregates, implying that protein quality control mechanisms are dysfunctional in these conditions. Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that are now recognized to overlap clinically and pathologically, forming a continuous disease spectrum. In this review article, we detail the evidence for dysregulation of protein quality control mechanisms across the whole ALS-FTD continuum, by discussing the major proteins implicated in ALS and/or FTD. We also discuss possible ways in which protein quality mechanisms could be targeted therapeutically in these disorders and highlight promising protein quality control-based therapeutics for clinical trials.
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Affiliation(s)
- Hamideh Shahheydari
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Audrey Ragagnin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Adam K Walker
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Reka P Toth
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Marta Vidal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Cyril J Jagaraj
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Emma R Perri
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Anna Konopka
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Jessica M Sultana
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Julie D Atkin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe UniversityMelbourne, VIC, Australia
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18
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Pin F, Minero VG, Penna F, Muscaritoli M, De Tullio R, Baccino FM, Costelli P. Interference with Ca 2+-Dependent Proteolysis Does Not Alter the Course of Muscle Wasting in Experimental Cancer Cachexia. Front Physiol 2017; 8:213. [PMID: 28469577 PMCID: PMC5395607 DOI: 10.3389/fphys.2017.00213] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Accepted: 03/23/2017] [Indexed: 01/24/2023] Open
Abstract
Protein hypercatabolism significantly contributes to the onset and progression of muscle wasting in cancer cachexia. In this regard, a major role is played by the ATP-ubiquitin-proteasome-dependent pathway and by autophagy. However, little is known about the relevance of the Ca2+-dependent proteolytic system. Since previous results suggested that this pathway is activated in the skeletal muscle of tumor hosts, the present study was aimed to investigate whether inhibition of Ca2+-dependent proteases (calpains) may improve cancer-induced muscle wasting. Two experimental models of cancer cachexia were used, namely the AH-130 Yoshida hepatoma and the C26 colon carcinoma. The Ca2+-dependent proteolytic system was inhibited by treating the animals with dantrolene or by overexpressing in the muscle calpastatin, the physiologic inhibitor of Ca2+-dependent proteases. The results confirm that calpain-1 is overexpressed and calpastatin is reduced in the muscle of rats implanted with the AH-130 hepatoma, and show for the first time that the Ca2+-dependent proteolytic system is overactivated also in the C26-bearing mice. Yet, administration of dantrolene, an inhibitor of the Ca2+-dependent proteases, did not modify tumor-induced body weight loss and muscle wasting in the AH-130 hosts. Dantrolene was also unable to reduce the enhancement of protein degradation rates occurring in rats bearing the AH-130 hepatoma. Similarly, overexpression of calpastatin in the tibialis muscle of the C26 hosts did not improve muscle wasting at all. These observations suggest that inhibiting a single proteolytic system is not a good strategy to contrast cancer-induced muscle wasting. In this regard, a more general and integrated approach aimed at targeting the catabolic stimuli rather than the proteolytic activity of a single pathway would likely be the most appropriate therapeutic intervention.
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Affiliation(s)
- Fabrizio Pin
- Department of Clinical and Biological Sciences, University of TurinTurin, Italy
| | - Valerio G Minero
- Department of Clinical and Biological Sciences, University of TurinTurin, Italy
| | - Fabio Penna
- Department of Clinical and Biological Sciences, University of TurinTurin, Italy
| | | | - Roberta De Tullio
- Department of Experimental Medicine, University of GenovaGenova, Italy
| | - Francesco M Baccino
- Department of Clinical and Biological Sciences, University of TurinTurin, Italy
| | - Paola Costelli
- Department of Clinical and Biological Sciences, University of TurinTurin, Italy
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19
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Darbyson A, Ngsee JK. Oxysterol-binding protein ORP3 rescues the Amyotrophic Lateral Sclerosis-linked mutant VAPB phenotype. Exp Cell Res 2016; 341:18-31. [PMID: 26812496 DOI: 10.1016/j.yexcr.2016.01.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 12/13/2022]
Abstract
A mutation in VAPB causes a familial form of Amyotrophic Lateral Sclerosis. The mutant protein (VAPB-P56S) is aggregate prone and blocks retrograde traffic from the endoplasmic reticulum (ER) Golgi intermediate compartment (ERGIC) including trafficking to the nuclear envelope (NE). Here we report a morphological screen where overexpression of oxysterol binding protein-related protein-3 (ORP3) rescued the mutant VAPB phenotype. It resolved the mutant VAPB-induced membrane expansions, restored solubility of the mutant protein in non-ionic detergent, and restored trafficking of Emerin to the NE. Knockdown of ORP3 or VAPB increased the intracellular level of phosphatidylinositol 4-phosphate (PtdIns4P). Decreasing PtdIns4P levels by inhibiting its synthesis reduced the severity of the mutant VAPB-induced membrane expansions and restored Emerin trafficking to the NE. Thus, VAPB and its interacting partners cooperatively regulate protein trafficking through the ERGIC by modulating PtdIns4P levels.
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Affiliation(s)
- Angie Darbyson
- Ottawa Hospital Research Institute Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
| | - Johnny K Ngsee
- Ottawa Hospital Research Institute Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5.
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20
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Autophagy and Neurodegeneration: Insights from a Cultured Cell Model of ALS. Cells 2015; 4:354-86. [PMID: 26287246 PMCID: PMC4588041 DOI: 10.3390/cells4030354] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/07/2015] [Accepted: 07/27/2015] [Indexed: 12/11/2022] Open
Abstract
Autophagy plays a major role in the elimination of cellular waste components, the renewal of intracellular proteins and the prevention of the build-up of redundant or defective material. It is fundamental for the maintenance of homeostasis and especially important in post-mitotic neuronal cells, which, without competent autophagy, accumulate protein aggregates and degenerate. Many neurodegenerative diseases are associated with defective autophagy; however, whether altered protein turnover or accumulation of misfolded, aggregate-prone proteins is the primary insult in neurodegeneration has long been a matter of debate. Amyotrophic lateral sclerosis (ALS) is a fatal disease characterized by selective degeneration of motor neurons. Most of the ALS cases occur in sporadic forms (SALS), while 10%–15% of the cases have a positive familial history (FALS). The accumulation in the cell of misfolded/abnormal proteins is a hallmark of both SALS and FALS, and altered protein degradation due to autophagy dysregulation has been proposed to contribute to ALS pathogenesis. In this review, we focus on the main molecular features of autophagy to provide a framework for discussion of our recent findings about the role in disease pathogenesis of the ALS-linked form of the VAPB gene product, a mutant protein that drives the generation of unusual cytoplasmic inclusions.
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21
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ALS-associated P56S-VAPB mutation restrains 3T3-L1 preadipocyte differentiation. Biochem Biophys Res Commun 2015; 460:831-7. [PMID: 25824044 DOI: 10.1016/j.bbrc.2015.03.118] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 03/22/2015] [Indexed: 02/06/2023]
Abstract
Amyotrophic lateral sclerosis (ALS), which is the most common motor neuron disease in adults, is a neurodegenerative disease that involves the selective and systematic death of upper and lower motor neurons. In addition to the motor neuron death, altered metabolic functions, such as dyslipidemia, have also been reported for ALS patients; however, the underlying mechanism remains unknown. In the present study, we investigated the effects of ALS-associated P56S-vesicle-associated membrane proteinassociated protein B (VAPB), P56S-VAPB on 3T3-L1 preadipocyte differentiation and on the expression of differentiation-associated genes and unfolded protein response (UPR)-related genes. Experiments with 3T3-L1 cells transfected with wild-type (Wt)-VAPB and P56S-VAPB expression vectors showed that the size of lipid droplets was markedly smaller in P56S-VAPB-expressing cells, although fat accumulated intracellularly. In P56S-VAPB-expressing cells, increased the expression of PPARγ2, aP2, and C/EBPα, the genes deeply involved in adipocyte differentiation, was not observed. Furthermore, the expression levels of the UPR-related ATF4 and CHOP genes were found to be enhanced in the P56S-VAPB-expressing cells. From these results, P56S-VAPB was found to suppress adipocyte differentiation by promoting the activation of the ATF4-CHOP pathway. Given previous reports showing increased ATF4 and CHOP expression levels in neurons of ALS patients, results from the present study suggest that dyslipidemia is caused by enhanced ATF4-CHOP pathway in the adipose tissue of ALS patients.
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22
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Genevini P, Papiani G, Ruggiano A, Cantoni L, Navone F, Borgese N. Amyotrophic lateral sclerosis-linked mutant VAPB inclusions do not interfere with protein degradation pathways or intracellular transport in a cultured cell model. PLoS One 2014; 9:e113416. [PMID: 25409455 PMCID: PMC4237408 DOI: 10.1371/journal.pone.0113416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 10/22/2014] [Indexed: 12/13/2022] Open
Abstract
VAPB is a ubiquitously expressed, ER-resident adaptor protein involved in interorganellar lipid exchange, membrane contact site formation, and membrane trafficking. Its mutant form, P56S-VAPB, which has been linked to a dominantly inherited form of Amyotrophic Lateral Sclerosis (ALS8), generates intracellular inclusions consisting in restructured ER domains whose role in ALS pathogenesis has not been elucidated. P56S-VAPB is less stable than the wild-type protein and, at variance with most pathological aggregates, its inclusions are cleared by the proteasome. Based on studies with cultured cells overexpressing the mutant protein, it has been suggested that VAPB inclusions may exert a pathogenic effect either by sequestering the wild-type protein and other interactors (loss-of-function by a dominant negative effect) or by a more general proteotoxic action (gain-of-function). To investigate P56S-VAPB degradation and the effect of the inclusions on proteostasis and on ER-to-plasma membrane protein transport in a more physiological setting, we used stable HeLa and NSC34 Tet-Off cell lines inducibly expressing moderate levels of P56S-VAPB. Under basal conditions, P56S-VAPB degradation was mediated exclusively by the proteasome in both cell lines, however, it could be targeted also by starvation-stimulated autophagy. To assess possible proteasome impairment, the HeLa cell line was transiently transfected with the ERAD (ER Associated Degradation) substrate CD3δ, while autophagic flow was investigated in cells either starved or treated with an autophagy-stimulating drug. Secretory pathway functionality was evaluated by analyzing the transport of transfected Vesicular Stomatitis Virus Glycoprotein (VSVG). P56S-VAPB expression had no effect either on the degradation of CD3δ or on the levels of autophagic markers, or on the rate of transport of VSVG to the cell surface. We conclude that P56S-VAPB inclusions expressed at moderate levels do not interfere with protein degradation pathways or protein transport, suggesting that the dominant inheritance of the mutant gene may be due mainly to haploinsufficiency.
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Affiliation(s)
- Paola Genevini
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche, and Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milano, Italy
| | - Giulia Papiani
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche, and Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milano, Italy
| | - Annamaria Ruggiano
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche, and Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milano, Italy
| | - Lavinia Cantoni
- Department of Molecular Biochemistry and Pharmacology, Istituto di Ricerche Farmacologiche “Mario Negri”, Milan, Italy
| | - Francesca Navone
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche, and Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milano, Italy
- * E-mail: (FN); (NB)
| | - Nica Borgese
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche, and Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milano, Italy
- Department of Health Science, Magna Graecia University of Catanzaro, Catanzaro, Italy
- * E-mail: (FN); (NB)
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23
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Bernard-Marissal N, Sunyach C, Marissal T, Raoul C, Pettmann B. Calreticulin levels determine onset of early muscle denervation by fast motoneurons of ALS model mice. Neurobiol Dis 2014; 73:130-6. [PMID: 25277755 DOI: 10.1016/j.nbd.2014.09.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/26/2014] [Accepted: 09/21/2014] [Indexed: 10/24/2022] Open
Abstract
Although the precise signaling mechanisms underlying the vulnerability of some sub-populations of motoneurons in ALS remain unclear, critical factors such as metallo-proteinase 9 expression, neuronal activity and endoplasmic reticulum stress have been shown to be involved. In the context of SOD1(G93A) ALS mouse model, we previously showed that a two-fold decrease in calreticulin (CRT) is occurring in the vulnerable fast motoneurons. Here, we asked to which extent the decrease in CRT levels was causative to muscle denervation and/or motoneuron degeneration. Toward this goal, a hemizygous deletion of the crt gene in SOD1(G93A) mice was generated since the complete ablation of crt is embryonic lethal. We observed that SOD1(G93A);crt(+/-) mice display increased and earlier muscle weakness and muscle denervation compared to SOD1(G93A) mice. While CRT reduction in motoneurons leads to a strong upregulation of two factors important in motoneuron dysfunction, ER stress and mTOR activation, it does not aggravate motoneuron death. Our results underline a prevalent role for CRT levels in the early phase of muscle denervation and support CRT regulation as a potential therapeutic approach.
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Affiliation(s)
- Nathalie Bernard-Marissal
- The Mediterranean Institute of Neurobiology, Inmed, Inserm U901, Marseille, France; The University of Lausanne, Department of Medical Genetics, Lausanne, Switzerland
| | - Claire Sunyach
- The Mediterranean Institute of Neurobiology, Inmed, Inserm U901, Marseille, France
| | - Thomas Marissal
- The School of Medicine, Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
| | - Cédric Raoul
- The Mediterranean Institute of Neurobiology, Inmed, Inserm U901, Marseille, France; The Neuroscience Institute Montpellier, Inserm UMR1051, Saint Eloi Hospital, Montpellier, France
| | - Brigitte Pettmann
- The Mediterranean Institute of Neurobiology, Inmed, Inserm U901, Marseille, France.
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Tadic V, Prell T, Lautenschlaeger J, Grosskreutz J. The ER mitochondria calcium cycle and ER stress response as therapeutic targets in amyotrophic lateral sclerosis. Front Cell Neurosci 2014; 8:147. [PMID: 24910594 PMCID: PMC4039088 DOI: 10.3389/fncel.2014.00147] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 05/07/2014] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive loss of upper and lower motor neurons. Although the etiology remains unclear, disturbances in calcium homoeostasis and protein folding are essential features of neurodegeneration in this disorder. Here, we review recent research findings on the interaction between endoplasmic reticulum (ER) and mitochondria, and its effect on calcium signaling and oxidative stress. We further provide insights into studies, providing evidence that structures of the ER mitochondria calcium cycle serve as a promising targets for therapeutic approaches for treatment of ALS.
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Affiliation(s)
- Vedrana Tadic
- Hans Berger Department of Neurology, Jena University HospitalJena, Germany
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25
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Jara JH, Genç B, Klessner JL, Ozdinler PH. Retrograde labeling, transduction, and genetic targeting allow cellular analysis of corticospinal motor neurons: implications in health and disease. Front Neuroanat 2014; 8:16. [PMID: 24723858 PMCID: PMC3972458 DOI: 10.3389/fnana.2014.00016] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 03/10/2014] [Indexed: 12/11/2022] Open
Abstract
Corticospinal motor neurons (CSMN) have a unique ability to receive, integrate, translate, and transmit the cerebral cortex's input toward spinal cord targets and therefore act as a “spokesperson” for the initiation and modulation of voluntary movements that require cortical input. CSMN degeneration has an immense impact on motor neuron circuitry and is one of the underlying causes of numerous neurodegenerative diseases, such as primary lateral sclerosis (PLS), hereditary spastic paraplegia (HSP), and amyotrophic lateral sclerosis (ALS). In addition, CSMN death results in long-term paralysis in spinal cord injury patients. Detailed cellular analyses are crucial to gain a better understanding of the pathologies underlying CSMN degeneration. However, visualizing and identifying these vulnerable neuron populations in the complex and heterogeneous environment of the cerebral cortex have proved challenging. Here, we will review recent developments and current applications of novel strategies that reveal the cellular and molecular basis of CSMN health and vulnerability. Such studies hold promise for building long-term effective treatment solutions in the near future.
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Affiliation(s)
- Javier H Jara
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Barış Genç
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - Jodi L Klessner
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA
| | - P Hande Ozdinler
- Davee Department of Neurology and Clinical Neurological Sciences, Feinberg School of Medicine, Northwestern University Chicago, IL, USA ; Robert H. Lurie Cancer Center, Feinberg School of Medicine, Northwestern University Chicago, IL, USA ; Cognitive Neurology and Alzheimer's Disease Center, Feinberg School of Medicine, Northwestern University Chicago IL, USA
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Sanhueza M, Zechini L, Gillespie T, Pennetta G. Gain-of-function mutations in the ALS8 causative gene VAPB have detrimental effects on neurons and muscles. Biol Open 2014; 3:59-71. [PMID: 24326187 PMCID: PMC3892161 DOI: 10.1242/bio.20137070] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a motor neuron degenerative disease characterized by a progressive, and ultimately fatal, muscle paralysis. The human VAMP-Associated Protein B (hVAPB) is the causative gene of ALS type 8. Previous studies have shown that a loss-of-function mechanism is responsible for VAPB-induced ALS. Recently, a novel mutation in hVAPB (V234I) has been identified but its pathogenic potential has not been assessed. We found that neuronal expression of the V234I mutant allele in Drosophila (DVAP-V260I) induces defects in synaptic structure and microtubule architecture that are opposite to those associated with DVAP mutants and transgenic expression of other ALS-linked alleles. Expression of DVAP-V260I also induces aggregate formation, reduced viability, wing postural defects, abnormal locomotion behavior, nuclear abnormalities, neurodegeneration and upregulation of the heat-shock-mediated stress response. Similar, albeit milder, phenotypes are associated with the overexpression of the wild-type protein. These data show that overexpressing the wild-type DVAP is sufficient to induce the disease and that DVAP-V260I is a pathogenic allele with increased wild-type activity. We propose that a combination of gain- and loss-of-function mechanisms is responsible for VAPB-induced ALS.
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Affiliation(s)
- Mario Sanhueza
- Centre for Integrative Physiology, Euan MacDonald Centre for Motor Neuron Disease Research, School of Biomedical Sciences, University of Edinburgh, Edinburgh EH8 9XD, UK
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ER Dysfunction and Protein Folding Stress in ALS. Int J Cell Biol 2013; 2013:674751. [PMID: 24324498 PMCID: PMC3845333 DOI: 10.1155/2013/674751] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 09/02/2013] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the most frequent paralytic disease in adults. Most ALS cases are considered sporadic with no clear genetic component. The disruption of protein homeostasis due to chronic stress responses at the endoplasmic reticulum (ER) and the accumulation of abnormal protein inclusions are extensively described in ALS mouse models and patient-derived tissue. Recent studies using pharmacological and genetic manipulation of the unfolded protein response (UPR), an adaptive reaction against ER stress, have demonstrated a complex involvement of the pathway in experimental models of ALS. In addition, quantitative changes in ER stress-responsive chaperones in body fluids have been proposed as possible biomarkers to monitor the disease progression. Here we review most recent advances attributing a causal role of ER stress in ALS.
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Saxena S, Roselli F, Singh K, Leptien K, Julien JP, Gros-Louis F, Caroni P. Neuroprotection through Excitability and mTOR Required in ALS Motoneurons to Delay Disease and Extend Survival. Neuron 2013; 80:80-96. [DOI: 10.1016/j.neuron.2013.07.027] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2013] [Indexed: 12/13/2022]
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29
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Crosstalk between Endoplasmic Reticulum Stress and Protein Misfolding in Neurodegenerative Diseases. ACTA ACUST UNITED AC 2013. [DOI: 10.1155/2013/256404] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Under physiological conditions, the endoplasmic reticulum (ER) is a central subcellular compartment for protein quality control in the secretory pathway that prevents protein misfolding and aggregation. Instrumental in protein quality control in the ER is the unfolded protein response (UPR), which is activated upon ER stress to reestablish homeostasis through a sophisticated transcriptionally and translationally regulated signaling network. However, this response can lead to apoptosis if the stress cannot be alleviated. The presence of abnormal protein aggregates containing specific misfolded proteins is recognized as the basis of numerous human conformational disorders, including neurodegenerative diseases. Here, I will highlight the overwhelming evidence that the presence of specific aberrant proteins in Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), prion diseases, and Amyotrophic Lateral Sclerosis (ALS) is intimately associated with perturbations in the ER protein quality control machinery that become incompetent to restore protein homeostasis and shift adaptive programs toward the induction of apoptotic signaling to eliminate irreversibly damaged neurons. Increasing our understanding about the deadly crosstalk between ER dysfunction and protein misfolding in these neurodegenerative diseases may stimulate the development of novel therapeutic strategies able to support neuronal survival and ameliorate disease progression.
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Calì T, Ottolini D, Brini M. Calcium and Endoplasmic Reticulum-Mitochondria Tethering in Neurodegeneration. DNA Cell Biol 2013; 32:140-6. [DOI: 10.1089/dna.2013.2011] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Tito Calì
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
| | - Denis Ottolini
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
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31
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Forrest S, Chai A, Sanhueza M, Marescotti M, Parry K, Georgiev A, Sahota V, Mendez-Castro R, Pennetta G. Increased levels of phosphoinositides cause neurodegeneration in a Drosophila model of amyotrophic lateral sclerosis. Hum Mol Genet 2013; 22:2689-704. [PMID: 23492670 PMCID: PMC3674808 DOI: 10.1093/hmg/ddt118] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Vesicle-associated membrane protein (VAMP)-Associated Protein B (VAPB) is the causative gene of amyotrophic lateral sclerosis 8 (ALS8) in humans. Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by selective death of motor neurons leading to spasticity, muscle atrophy and paralysis. VAP proteins have been implicated in various cellular processes, including intercellular signalling, synaptic remodelling, lipid transport and membrane trafficking and yet, the molecular mechanisms underlying ALS8 pathogenesis remain poorly understood. We identified the conserved phosphoinositide phosphatase Sac1 as a Drosophila VAP (DVAP)-binding partner and showed that DVAP is required to maintain normal levels of phosphoinositides. Downregulating either Sac1 or DVAP disrupts axonal transport, synaptic growth, synaptic microtubule integrity and the localization of several postsynaptic components. Expression of the disease-causing allele (DVAP-P58S) in a fly model for ALS8 induces neurodegeneration, elicits synaptic defects similar to those of DVAP or Sac1 downregulation and increases phosphoinositide levels. Consistent with a role for Sac1-mediated increase of phosphoinositide levels in ALS8 pathogenesis, we found that Sac1 downregulation induces neurodegeneration in a dosage-dependent manner. In addition, we report that Sac1 is sequestered into the DVAP-P58S-induced aggregates and that reducing phosphoinositide levels rescues the neurodegeneration and suppresses the synaptic phenotypes associated with DVAP-P58S transgenic expression. These data underscore the importance of DVAP–Sac1 interaction in controlling phosphoinositide metabolism and provide mechanistic evidence for a crucial role of phosphoinositide levels in VAP-induced ALS.
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Affiliation(s)
- Stuart Forrest
- Center for Integrative Physiology and Euan MacDonald Center for Motor Neuron Disease Research, School of Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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32
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Kabashi E, El Oussini H, Bercier V, Gros-Louis F, Valdmanis PN, McDearmid J, Mejier IA, Dion PA, Dupre N, Hollinger D, Sinniger J, Dirrig-Grosch S, Camu W, Meininger V, Loeffler JP, René F, Drapeau P, Rouleau GA, Dupuis L. Investigating the contribution of VAPB/ALS8 loss of function in amyotrophic lateral sclerosis. Hum Mol Genet 2013; 22:2350-60. [DOI: 10.1093/hmg/ddt080] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Qiu L, Qiao T, Beers M, Tan W, Wang H, Yang B, Xu Z. Widespread aggregation of mutant VAPB associated with ALS does not cause motor neuron degeneration or modulate mutant SOD1 aggregation and toxicity in mice. Mol Neurodegener 2013; 8:1. [PMID: 23281774 PMCID: PMC3538568 DOI: 10.1186/1750-1326-8-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 12/29/2012] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND A proline-to-serine substitution at position-56 (P56S) of vesicle-associated membrane protein-associated protein B (VAPB) causes a form of dominantly inherited motor neuron disease (MND), including typical and atypical amyotrophic lateral sclerosis (ALS) and a mild late-onset spinal muscular atrophy (SMA). VAPB is an integral endoplasmic reticulum (ER) protein and has been implicated in various cellular processes, including ER stress, the unfolded protein response (UPR) and Ca2+ homeostasis. However, it is unclear how the P56S mutation leads to neurodegeneration and muscle atrophy in patients. The formation of abnormal VAPB-positive inclusions by mutant VAPB suggests a possible toxic gain of function as an underlying mechanism. Furthermore, the amount of VAPB protein is reported to be reduced in sporadic ALS patients and mutant SOD1G93A mice, leading to the hypothesis that wild type VAPB plays a role in the pathogenesis of ALS without VAPB mutations. RESULTS To investigate the pathogenic mechanism in vivo, we generated human wild type (wtVAPB) and mutant VAPB (muVAPB) transgenic mice that expressed the transgenes broadly in the CNS. We observed robust VAPB-positive aggregates in the spinal cord of muVAPB transgenic mice. However, we failed to find an impairment of motor function and motor neuron degeneration. We also did not detect any change in the endogenous VAPB level or evidence for induction of the unfolded protein response (UPR) and coaggregation of VAPA with muVAPB. Furthermore, we crossed these VAPB transgenic mice with mice that express mutant SOD1G93A and develop motor neuron degeneration. Overexpression of neither wtVAPB nor muVAPB modulated the protein aggregation and disease progression in the SOD1G93A mice. CONCLUSION Overexpression of VAPBP56S mutant to approximately two-fold of the endogenous VAPB in mouse spinal cord produced abundant VAPB aggregates but was not sufficient to cause motor dysfunction or motor neuron degeneration. Furthermore, overexpression of either muVAPB or wtVAPB does not modulate the course of ALS in SOD1G93A mice. These results suggest that changes in wild type VAPB do not play a significant role in ALS cases that are not caused by VAPB mutations. Furthermore, these results suggest that muVAPB aggregates are innocuous and do not cause motor neuron degeneration by a gain-of-toxicity, and therefore, a loss of function may be the underlying mechanism.
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Affiliation(s)
- Linghua Qiu
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01602, USA.
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Cozzolino M, Pesaresi MG, Gerbino V, Grosskreutz J, Carrì MT. Amyotrophic lateral sclerosis: new insights into underlying molecular mechanisms and opportunities for therapeutic intervention. Antioxid Redox Signal 2012; 17:1277-330. [PMID: 22413952 DOI: 10.1089/ars.2011.4328] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent years have witnessed a renewed interest in the pathogenic mechanisms of amyotrophic lateral sclerosis (ALS), a late-onset progressive degeneration of motor neurons. The discovery of new genes associated with the familial form of the disease, along with a deeper insight into pathways already described for this disease, has led scientists to reconsider previous postulates. While protein misfolding, mitochondrial dysfunction, oxidative damage, defective axonal transport, and excitotoxicity have not been dismissed, they need to be re-examined as contributors to the onset or progression of ALS in the light of the current knowledge that the mutations of proteins involved in RNA processing, apparently unrelated to the previous "old partners," are causative of the same phenotype. Thus, newly envisaged models and tools may offer unforeseen clues on the etiology of this disease and hopefully provide the key to treatment.
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Reduced calreticulin levels link endoplasmic reticulum stress and Fas-triggered cell death in motoneurons vulnerable to ALS. J Neurosci 2012; 32:4901-12. [PMID: 22492046 DOI: 10.1523/jneurosci.5431-11.2012] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cellular responses to protein misfolding are thought to play key roles in triggering neurodegeneration. In the mutant superoxide dismutase (mSOD1) model of amyotrophic lateral sclerosis (ALS), subsets of motoneurons are selectively vulnerable to degeneration. Fast fatigable motoneurons selectively activate an endoplasmic reticulum (ER) stress response that drives their early degeneration while a subset of mSOD1 motoneurons show exacerbated sensitivity to activation of the motoneuron-specific Fas/NO pathway. However, the links between the two mechanisms and the molecular basis of their cellular specificity remained unclear. We show that Fas activation leads, specifically in mSOD1 motoneurons, to reductions in levels of calreticulin (CRT), a calcium-binding ER chaperone. Decreased expression of CRT is both necessary and sufficient to trigger SOD1(G93A) motoneuron death through the Fas/NO pathway. In SOD1(G93A) mice in vivo, reductions in CRT precede muscle denervation and are restricted to vulnerable motor pools. In vitro, both reduced CRT and Fas activation trigger an ER stress response that is restricted to, and required for death of, vulnerable SOD1(G93A) motoneurons. Our data reveal CRT as a critical link between a motoneuron-specific death pathway and the ER stress response and point to a role of CRT levels in modulating motoneuron vulnerability to ALS.
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Calì T, Ottolini D, Brini M. Mitochondrial Ca(2+) and neurodegeneration. Cell Calcium 2012; 52:73-85. [PMID: 22608276 PMCID: PMC3396847 DOI: 10.1016/j.ceca.2012.04.015] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 04/18/2012] [Accepted: 04/20/2012] [Indexed: 12/16/2022]
Abstract
Mitochondria are essential for ensuring numerous fundamental physiological processes such as cellular energy, redox balance, modulation of Ca2+ signaling and important biosynthetic pathways. They also govern the cell fate by participating in the apoptosis pathway. The mitochondrial shape, volume, number and distribution within the cells are strictly controlled. The regulation of these parameters has an impact on mitochondrial function, especially in the central nervous system, where trafficking of mitochondria is critical to their strategic intracellular distribution, presumably according to local energy demands. Thus, the maintenance of a healthy mitochondrial population is essential to avoid the impairment of the processes they regulate: for this purpose, cells have developed mechanisms involving a complex system of quality control to remove damaged mitochondria, or to renew them. Defects of these processes impair mitochondrial function and lead to disordered cell function, i.e., to a disease condition. Given the standard role of mitochondria in all cells, it might be expected that their dysfunction would give rise to similar defects in all tissues. However, damaged mitochondrial function has pleiotropic effects in multicellular organisms, resulting in diverse pathological conditions, ranging from cardiac and brain ischemia, to skeletal muscle myopathies to neurodegenerative diseases. In this review, we will focus on the relationship between mitochondrial (and cellular) derangements and Ca2+ dysregulation in neurodegenerative diseases, emphasizing the evidence obtained in genetic models. Common patterns, that recognize the derangement of Ca2+ and energy control as a causative factor, have been identified: advances in the understanding of the molecular regulation of Ca2+ homeostasis, and on the ways in which it could become perturbed in neurological disorders, may lead to the development of therapeutic strategies that modulate neuronal Ca2+ signaling.
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Affiliation(s)
- Tito Calì
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
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Lautenschlaeger J, Prell T, Grosskreutz J. Endoplasmic reticulum stress and the ER mitochondrial calcium cycle in amyotrophic lateral sclerosis. ACTA ACUST UNITED AC 2012; 13:166-77. [PMID: 22292840 DOI: 10.3109/17482968.2011.641569] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The endoplasmic reticulum (ER) is a multifunctional organelle involved in protein synthesis, processing and folding, in intracellular transport and calcium signalling. ER stress can be triggered by depletion of ER calcium content and the accumulation of un- and mis-folded proteins, and relays stress signals to the ER mitochondria calcium cycle (ERMCC) and to the nucleus and protein translation machinery. The ensuing unfolded protein response (UPR) helps to cope with ER stress. Total protein synthesis is inhibited to keep protein load low, while the synthesis of ER chaperones, which assist protein folding, is induced. If cell integrity cannot be restored, signal cascades mediating cell death are activated. This review focuses on the role of ER stress and the UPR in the pathology of amyotrophic lateral sclerosis (ALS). The triggers for ER stress are as yet unclear, but induction of UPR sensor proteins, up-regulation of chaperones and induction of cell death proteins have been described in human post mortem ALS tissue and in mutant superoxide dismutase-1 (SOD1) expressing models of ALS. TDP-43 and VAPB seem to be involved in UPR signalling as well. Recent reports raise hope that UPR sensor proteins become effective therapeutic targets in the treatment of ALS.
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Affiliation(s)
- Janin Lautenschlaeger
- Hans-Berger Department of Neurology, Friedrich-Schiller-University Jena, Erlanger Allee 101, Jena, Germany.
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38
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De Vos KJ, Mórotz GM, Stoica R, Tudor EL, Lau KF, Ackerley S, Warley A, Shaw CE, Miller CC. VAPB interacts with the mitochondrial protein PTPIP51 to regulate calcium homeostasis. Hum Mol Genet 2012; 21:1299-311. [PMID: 22131369 PMCID: PMC3284118 DOI: 10.1093/hmg/ddr559] [Citation(s) in RCA: 388] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 11/01/2011] [Accepted: 11/22/2011] [Indexed: 12/12/2022] Open
Abstract
A proline to serine substitution at position 56 in the gene encoding vesicle-associated membrane protein-associated protein B (VAPB) causes some dominantly inherited familial forms of motor neuron disease including amyotrophic lateral sclerosis (ALS) type-8. VAPB is an integral endoplasmic reticulum (ER) protein whose amino-terminus projects into the cytosol. Overexpression of ALS mutant VAPBP56S disrupts ER structure but the mechanisms by which it induces disease are not properly understood. Here we show that VAPB interacts with the outer mitochondrial membrane protein, protein tyrosine phosphatase-interacting protein 51 (PTPIP51). ER and mitochondria are both stores for intracellular calcium (Ca(2+)) and Ca(2+) exchange between these organelles occurs at regions of ER that are closely apposed to mitochondria. These are termed mitochondria-associated membranes (MAM). We demonstrate that VAPB is a MAM protein and that loss of either VAPB or PTPIP51 perturbs uptake of Ca(2+) by mitochondria following release from ER stores. Finally, we demonstrate that VAPBP56S has altered binding to PTPIP51 and increases Ca(2+) uptake by mitochondria following release from ER stores. Damage to ER, mitochondria and Ca(2+) homeostasis are all seen in ALS and we discuss the implications of our findings in this context.
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Affiliation(s)
- Kurt J. De Vos
- Department of Neuroscience and
- Department of Clinical Neurosciences, MRC Centre for Neurodegeneration Research, Institute of Psychiatry, King's College London, London SE5 8AF, UK
| | | | | | | | - Kwok-Fai Lau
- Department of Neuroscience and
- Department of Biochemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong and
| | | | - Alice Warley
- Centre for Ultrastructural Imaging, King's College London, London SE1 1UL, UK
| | - Christopher E. Shaw
- Department of Clinical Neurosciences, MRC Centre for Neurodegeneration Research, Institute of Psychiatry, King's College London, London SE5 8AF, UK
| | - Christopher C.J. Miller
- Department of Neuroscience and
- Department of Clinical Neurosciences, MRC Centre for Neurodegeneration Research, Institute of Psychiatry, King's College London, London SE5 8AF, UK
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Mikitova V, Levine TP. Analysis of the key elements of FFAT-like motifs identifies new proteins that potentially bind VAP on the ER, including two AKAPs and FAPP2. PLoS One 2012; 7:e30455. [PMID: 22276202 PMCID: PMC3261905 DOI: 10.1371/journal.pone.0030455] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/20/2011] [Indexed: 12/13/2022] Open
Abstract
Background Two phenylalanines (FF) in an acidic tract (FFAT)-motifs were originally described as having seven elements: an acidic flanking region followed by 6 residues (EFFDA–E). Such motifs are found in several lipid transfer protein (LTP) families, and they interact with a protein on the cytosolic face of the ER called vesicle-associated membrane protein-associated protein (VAP). Mutation of which causes ER stress and motor neuron disease, making it important to determine which proteins bind VAP. Among other proteins that bind VAP, some contain FFAT-like motifs that are missing one or more of the seven elements. Defining how much variation is tolerated in FFAT-like motifs is a preliminary step prior to the identification of the full range of VAP interactors. Results We used a quantifiable in vivo system that measured ER targeting in a reporter yeast strain that over-expressed VAP to study the effect of substituting different elements of FFAT-like motifs in turn. By defining FFAT-like motifs more widely than before, we found them in novel proteins the functions of which had not previously been directly linked to the ER, including: two PKA anchoring proteins, AKAP220 and AKAP110; a family of plant LTPs; and the glycolipid LTP phosphatidylinositol-four-phosphate adaptor-protein-2 (FAPP-2). Conclusion All of the seven essential elements of a FFAT motif tolerate variation, and weak targeting to the ER via VAP is still detected if two elements are substituted. In addition to the strong FFAT motifs already known, there are additional proteins with weaker FFAT-like motifs, which might be functionally important VAP interactors.
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Affiliation(s)
- Veronika Mikitova
- Department of Cell Biology, University College London Institute of Ophthalmology, London, United Kingdom
| | - Timothy P. Levine
- Department of Cell Biology, University College London Institute of Ophthalmology, London, United Kingdom
- * E-mail:
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Mórotz GM, De Vos KJ, Vagnoni A, Ackerley S, Shaw CE, Miller CCJ. Amyotrophic lateral sclerosis-associated mutant VAPBP56S perturbs calcium homeostasis to disrupt axonal transport of mitochondria. Hum Mol Genet 2012; 21:1979-88. [PMID: 22258555 PMCID: PMC3315205 DOI: 10.1093/hmg/dds011] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A proline-to-serine substitution at position 56 in the gene encoding vesicle-associated membrane protein-associated protein B (VAPB; VAPBP56S) causes some dominantly inherited familial forms of motor neuron disease, including amyotrophic lateral sclerosis (ALS) type-8. Here, we show that expression of ALS mutant VAPBP56S but not wild-type VAPB in neurons selectively disrupts anterograde axonal transport of mitochondria. VAPBP56S-induced disruption of mitochondrial transport involved reductions in the frequency, velocity and persistence of anterograde mitochondrial movement. Anterograde axonal transport of mitochondria is mediated by the microtubule-based molecular motor kinesin-1. Attachment of kinesin-1 to mitochondria involves the outer mitochondrial membrane protein mitochondrial Rho GTPase-1 (Miro1) which acts as a sensor for cytosolic calcium levels ([Ca2+]c); elevated [Ca2+]c disrupts mitochondrial transport via an effect on Miro1. To gain insight into the mechanisms underlying the VAPBP56S effect on mitochondrial transport, we monitored [Ca2+]c levels in VAPBP56S-expressing neurons. Expression of VAPBP56S but not VAPB increased resting [Ca2+]c and this was associated with a reduction in the amounts of tubulin but not kinesin-1 that were associated with Miro1. Moreover, expression of a Ca2+ insensitive mutant of Miro1 rescued defective mitochondrial axonal transport and restored the amounts of tubulin associated with the Miro1/kinesin-1 complex to normal in VAPBP56S-expressing cells. Our results suggest that ALS mutant VAPBP56S perturbs anterograde mitochondrial axonal transport by disrupting Ca2+ homeostasis and effecting the Miro1/kinesin-1 interaction with tubulin.
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Affiliation(s)
- Gábor M Mórotz
- Department of Neuroscience, Institute of Psychiatry, Kings College London, London, UK
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41
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VapB as a regulator of osteoclastogenesis via modulation of PLCγ2-Ca2+-NFAT signaling. FEBS Lett 2012; 586:263-9. [DOI: 10.1016/j.febslet.2011.12.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/08/2011] [Accepted: 12/28/2011] [Indexed: 11/24/2022]
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42
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Accumulation of wildtype and ALS-linked mutated VAPB impairs activity of the proteasome. PLoS One 2011; 6:e26066. [PMID: 21998752 PMCID: PMC3187839 DOI: 10.1371/journal.pone.0026066] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 09/19/2011] [Indexed: 11/19/2022] Open
Abstract
Cellular homeostasis relies on a tight control of protein synthesis, folding and degradation, in which the endoplasmic reticulum (ER) quality control and the ubiquitin proteasome system (UPS) have an instrumental function. ER stress and aberrant accumulation of misfolded proteins represent a pathological signature of amyotrophic lateral sclerosis (ALS), a fatal paralytic disorder caused by the selective degeneration of motoneurons in the brain and spinal cord. Mutations in the ER-resident protein VAPB have been associated with familial forms of the disease. ALS-linked mutations cause VAPB to form cytoplasmic aggregates. We previously demonstrated that viral-mediated expression of both wildtype and mutant human VAPB (hVAPB) leads to an ER stress response that contributes to the selective death of motoneurons. However, the mechanisms behind ER stress, defective UPS and hVAPB-associated motoneuron degeneration remain elusive. Here, we show that the overexpression of wildtype and mutated hVAPB, which is found to be less stable than the wildtype protein, leads to the abnormal accumulation of ubiquitin and ubiquitin-like protein conjugates in non-human primate cells. We observed that overexpression of both forms of hVAPB elicited an ER stress response. Treatment of wildtype and mutated hVAPB expressing cells with the ER stress inhibitor salubrinal diminished the burden of ubiquitinated proteins, suggesting that ER stress contributes to the impairment of proteasome function. We also found that both wildtype and mutated hVAPB can associate with the 20S proteasome, which was found to accumulate at the ER with wildtype hVAPB or in mutant hVAPB aggregates. Our results suggest that ER stress and corruption of the proteasome function might contribute to the aberrant protein homeostasis associated with hVAPB.
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43
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Walker AK, Atkin JD. Stress signaling from the endoplasmic reticulum: A central player in the pathogenesis of amyotrophic lateral sclerosis. IUBMB Life 2011; 63:754-63. [PMID: 21834058 DOI: 10.1002/iub.520] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 05/24/2011] [Indexed: 12/15/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by the misfolding and aggregation of distinct proteins in affected tissues, however, the pathogenic cause of disease remains unknown. Recent evidence indicates that endoplasmic reticulum (ER) stress plays a central role in ALS pathogenesis. ER stress activates the unfolded protein response (UPR), a homeostatic response to misfolded proteins. The UPR is initially protective by up-regulation of specific ER stress-regulated genes and inhibition of general protein translation. However, long-term ER stress leads to cell death via apoptotic signaling, thus providing a link to neurodegeneration. Activation of the UPR is one of the earliest events in affected motor neurons of transgenic rodent models expressing ALS-linked mutant superoxide dismutase 1 (SOD1). Recently, genetic manipulation of ER stress in several different SOD1 mouse models was shown to alter disease onset and progression, implicating an active role for the UPR in disease mechanisms. Furthermore, mutations to vesicle-associated membrane protein-associated protein B (VAPB), an ER transmembrane protein involved in ER stress regulation, also cause some cases of familial ALS. ER stress also occurs in spinal cord tissues of human sporadic ALS patients, and recent evidence suggests that perturbation of the ER could occur in ALS cases associated with TAR DNA binding protein 43 (TDP-43), fused in sarcoma (FUS) and valosin containing protein (VCP). Together these findings implicate ER stress as a potential upstream mechanism involved in both familial and sporadic forms of ALS.
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Affiliation(s)
- Adam K Walker
- Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Bundoora, VIC, Australia
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44
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Stutzmann GE, Mattson MP. Endoplasmic reticulum Ca(2+) handling in excitable cells in health and disease. Pharmacol Rev 2011; 63:700-27. [PMID: 21737534 DOI: 10.1124/pr.110.003814] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The endoplasmic reticulum (ER) is a morphologically and functionally diverse organelle capable of integrating multiple extracellular and internal signals and generating adaptive cellular responses. It plays fundamental roles in protein synthesis and folding and in cellular responses to metabolic and proteotoxic stress. In addition, the ER stores and releases Ca(2+) in sophisticated scenarios that regulate a range of processes in excitable cells throughout the body, including muscle contraction and relaxation, endocrine regulation of metabolism, learning and memory, and cell death. One or more Ca(2+) ATPases and two types of ER membrane Ca(2+) channels (inositol trisphosphate and ryanodine receptors) are the major proteins involved in ER Ca(2+) uptake and release, respectively. There are also direct and indirect interactions of ER Ca(2+) stores with plasma membrane and mitochondrial Ca(2+)-regulating systems. Pharmacological agents that selectively modify ER Ca(2+) release or uptake have enabled studies that revealed many different physiological roles for ER Ca(2+) signaling. Several inherited diseases are caused by mutations in ER Ca(2+)-regulating proteins, and perturbed ER Ca(2+) homeostasis is implicated in a range of acquired disorders. Preclinical investigations suggest a therapeutic potential for use of agents that target ER Ca(2+) handling systems of excitable cells in disorders ranging from cardiac arrhythmias and skeletal muscle myopathies to Alzheimer disease.
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Affiliation(s)
- Grace E Stutzmann
- Department of Neuroscience, Rosalind Franklin University/The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL 60064, USA.
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45
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Liu Y, Lee SY, Neely E, Nandar W, Moyo M, Simmons Z, Connor JR. Mutant HFE H63D protein is associated with prolonged endoplasmic reticulum stress and increased neuronal vulnerability. J Biol Chem 2011; 286:13161-70. [PMID: 21349849 PMCID: PMC3075663 DOI: 10.1074/jbc.m110.170944] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 02/22/2011] [Indexed: 12/11/2022] Open
Abstract
A specific polymorphism in the hemochromatosis (HFE) gene, H63D, is over-represented in neurodegenerative disorders such as amyotrophic lateral sclerosis and Alzheimer disease. Mutations of HFE are best known as being associated with cellular iron overload, but the mechanism by which HFE H63D might increase the risk of neuron degeneration is unclear. Here, using an inducible expression cell model developed from a human neuronal cell line SH-SY5Y, we reported that the presence of the HFE H63D protein activated the unfolded protein response (UPR). This response was followed by a persistent endoplasmic reticulum (ER) stress, as the signals of UPR sensors attenuated and followed by up-regulation of caspase-3 cleavage and activity. Our in vitro findings were recapitulated in a transgenic mouse model carrying Hfe H67D, the mouse equivalent of the human H63D mutation. In this model, UPR activation was detected in the lumbar spinal cord at 6 months then declined at 12 months in association with increased caspase-3 cleavage. Moreover, upon the prolonged ER stress, the number of cells expressing HFE H63D in early apoptosis was increased moderately. Cell proliferation was decreased without increased cell death. Additionally, despite increased iron level in cells carrying HFE H63D, it appeared that ER stress was not responsive to the change of cellular iron status. Overall, our studies indicate that the HFE H63D mutant protein is associated with prolonged ER stress and chronically increased neuronal vulnerability.
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Affiliation(s)
- Yiting Liu
- Department of Neurosurgery, Pennsylvania State University, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA.
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46
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Lopes JP, Agostinho P. Cdk5: multitasking between physiological and pathological conditions. Prog Neurobiol 2011; 94:49-63. [PMID: 21473899 DOI: 10.1016/j.pneurobio.2011.03.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2010] [Revised: 03/28/2011] [Accepted: 03/28/2011] [Indexed: 01/11/2023]
Abstract
Cyclin-dependent kinase 5 (Cdk5) is a peculiar proline-directed serine/threonine kinase. Unlike the other members of the Cdk family, Cdk5 is not directly involved in cell cycle regulation, being normally associated with neuronal processes such as migration, cortical layering and synaptic plasticity. This kinase is present mainly in post-mitotic neurons and its activity is tightly regulated by the interaction with the specific activators, p35 and p39. Despite its pivotal role in CNS development, Cdk5 dysregulation has been implicated in different pathologies, such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Parkinson's disease (PD) and, most recently, prion-related encephalopathies (PRE). In these neurodegenerative conditions, Cdk5 overactivation and relocalization occurs upon association with p25, a truncated form of the normal activator p35. This activator switching will cause a shift in the phosphorylative pattern of Cdk5, with an alteration both in targets and activity, ultimately leading to neuronal demise. In AD and PRE, two disorders that share clinical and neuropathological features, Cdk5 dysregulation is a linking event between the major neuropathological markers: amyloid plaques, tau hyperphosphorylation and synaptic and neuronal loss. Moreover, this kinase was shown to be involved in abortive cell cycle re-entry, a feature recently proposed as a possible step in the neuronal apoptosis mechanism of several neurological diseases. This review focuses on the role of Cdk5 in neurons, namely in the regulation of cytoskeletal dynamics, synaptic function and cell survival, both in physiological and in pathological conditions, highlighting the relevance of Cdk5 in the main mechanisms of neurodegeneration in Alzheimer's disease and other brain pathologies.
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Affiliation(s)
- Joao P Lopes
- Center for Neuroscience and Cell Biology, Faculty of Medicine, Biochemistry Institute, University of Coimbra, 3004 Coimbra, Portugal.
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47
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Gkogkas C, Wardrope C, Hannah M, Skehel P. The ALS8-associated mutant VAPB(P56S) is resistant to proteolysis in neurons. J Neurochem 2011; 117:286-94. [PMID: 21275991 DOI: 10.1111/j.1471-4159.2011.07201.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
VAMP/synaptobrevin associated proteins A and B (VAPA and VAPB), are type IV membrane proteins enriched on ER and Golgi membranes. Both VAPA and B interact with cytoplasmic lipid transport proteins and cytoskeletal elements to maintain the structure and composition of ER and Golgi membranes. Truncated forms of both proteins are present in some tissues but the functional significance of this is not clear. In rodents processing of VAPA occurs in most tissues, however, truncated forms of VAPB have only been reported in brain tissue. It is demonstrated here that the extent of VAPB processing in rat increases during postnatal development and that it is restricted to neurons. The C-terminal polypeptide generated by this cleavage reaction remains associated with cell membranes, but its subcellular distribution is distinct from the full-length protein. A mutant form of VAPB is associated with a familial form of neurodegenerative disease, amyotrophic lateral sclerosis type 8. The mutant protein, VAPB(P56S) , is resistant to truncation in primary neuronal cultures, although remains sensitive to some form of proteolysis when over-expressed in HEK293 cells. These data suggest that neuronal cells have a particular requirement for VAPB proteolysis and that reduced levels of processed polypeptides may contribute to the neurodegeneration associated with amyotrophic lateral sclerosis type 8.
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Affiliation(s)
- Christos Gkogkas
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh, UK
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48
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Matus S, Glimcher LH, Hetz C. Protein folding stress in neurodegenerative diseases: a glimpse into the ER. Curr Opin Cell Biol 2011; 23:239-52. [PMID: 21288706 DOI: 10.1016/j.ceb.2011.01.003] [Citation(s) in RCA: 164] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 01/05/2011] [Accepted: 01/11/2011] [Indexed: 01/19/2023]
Abstract
Several neurodegenerative diseases share common neuropathology, primarily featuring the presence in the brain of abnormal protein inclusions containing specific misfolded proteins. Recent evidence indicates that alteration in organelle function is a common pathological feature of protein misfolding disorders, highlighting perturbations in the homeostasis of the endoplasmic reticulum (ER). Signs of ER stress have been detected in most experimental models of neurological disorders and more recently in brain samples from human patients with neurodegenerative disease. To cope with ER stress, cells activate an integrated signaling response termed the unfolded protein response (UPR), which aims to reestablish homeostasis in part through regulation of genes involved in protein folding, quality control and degradation pathways. Here we discuss the particular mechanisms currently proposed to be involved in the generation of protein folding stress in different neurodegenerative conditions and speculate about possible therapeutic interventions.
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Affiliation(s)
- Soledad Matus
- Center for Molecular Studies of Cell, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
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49
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IFNγ triggers a LIGHT-dependent selective death of motoneurons contributing to the non-cell-autonomous effects of mutant SOD1. Cell Death Differ 2010; 18:754-68. [PMID: 21072055 DOI: 10.1038/cdd.2010.143] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease that primarily affects motoneurons in the brain and spinal cord. Dominant mutations in superoxide dismutase-1 (SOD1) cause a familial form of ALS. Mutant SOD1-damaged glial cells contribute to ALS pathogenesis by releasing neurotoxic factors, but the mechanistic basis of the motoneuron-specific elimination is poorly understood. Here, we describe a motoneuron-selective death pathway triggered by activation of lymphotoxin-β receptor (LT-βR) by LIGHT, and operating by a novel signaling scheme. We show that astrocytes expressing mutant SOD1 mediate the selective death of motoneurons through the proinflammatory cytokine interferon-γ (IFNγ), which activates the LIGHT-LT-βR death pathway. The expression of LIGHT and LT-βR by motoneurons in vivo correlates with the preferential expression of IFNγ by motoneurons and astrocytes at disease onset and symptomatic stage in ALS mice. Importantly, the genetic ablation of Light in an ALS mouse model retards progression, but not onset, of the disease and increases lifespan. We propose that IFNγ contributes to a cross-talk between motoneurons and astrocytes causing the selective loss of some motoneurons following activation of the LIGHT-induced death pathway.
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50
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Musarò A. State of the art and the dark side of amyotrophic lateral sclerosis. World J Biol Chem 2010; 1:62-8. [PMID: 21540991 PMCID: PMC3083964 DOI: 10.4331/wjbc.v1.i5.62] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 05/22/2010] [Accepted: 05/24/2010] [Indexed: 02/05/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disorder that involves the degeneration of motor neurons, muscle atrophy, and paralysis. In a few familiar forms of ALS, mutations in the superoxide dismutase-1 (SOD1) gene have been held responsible for the degeneration of motor neurons. Nevertheless, after the discovery of the SOD1 mutations no consensus has emerged as to which cells, tissues and pathways are primarily implicated in the pathogenic events that lead to ALS. Ubiquitous overexpression of mutant SOD1 in transgenic animals recapitulates the pathological features of ALS. However, the toxicity of mutant SOD1 is not necessarily limited to the central nervous system. Views about ALS pathogenesis are now enriched by the recent discovery of mutations in a pair of DNA/RNA-binding proteins called TDP-43 and FUS/TLS as causes of familial and sporadic forms of ALS. Although the steps that lead to the pathological state are well defined, several fundamental issues are still controversial: are the motor neurons the first direct targets of ALS; and what is the contribution of non-neuronal cells, if any, to the pathogenesis of ALS? The state of the art of ALS pathogenesis and the open questions are discussed in this review.
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Affiliation(s)
- Antonio Musarò
- Antonio Musarò, Department of Histology and Medical Embryology, Institute Pasteur Cenci-Bolognetti, IIM, Sapienza University of Rome, Rome 00161, Italy
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