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Wai T. Is mitochondrial morphology important for cellular physiology? Trends Endocrinol Metab 2024:S1043-2760(24)00123-1. [PMID: 38866638 DOI: 10.1016/j.tem.2024.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 05/07/2024] [Accepted: 05/13/2024] [Indexed: 06/14/2024]
Abstract
Mitochondria are double membrane-bound organelles the network morphology of which in cells is shaped by opposing events of fusion and fission executed by dynamin-like GTPases. Mutations in these genes can perturb the form and functions of mitochondria in cell and animal models of mitochondrial diseases. An expanding array of chemical, mechanical, and genetic stressors can converge on mitochondrial-shaping proteins and disrupt mitochondrial morphology. In recent years, studies aimed at disentangling the multiple roles of mitochondrial-shaping proteins beyond fission or fusion have provided insights into the homeostatic relevance of mitochondrial morphology. Here, I review the pleiotropy of mitochondrial fusion and fission proteins with the aim of understanding whether mitochondrial morphology is important for cell and tissue physiology.
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Affiliation(s)
- Timothy Wai
- Institut Pasteur, Mitochondrial Biology, CNRS UMR 3691, Université Paris Cité, Paris, France.
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2
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Liu BH, Xu CZ, Liu Y, Lu ZL, Fu TL, Li GR, Deng Y, Luo GQ, Ding S, Li N, Geng Q. Mitochondrial quality control in human health and disease. Mil Med Res 2024; 11:32. [PMID: 38812059 PMCID: PMC11134732 DOI: 10.1186/s40779-024-00536-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 05/07/2024] [Indexed: 05/31/2024] Open
Abstract
Mitochondria, the most crucial energy-generating organelles in eukaryotic cells, play a pivotal role in regulating energy metabolism. However, their significance extends beyond this, as they are also indispensable in vital life processes such as cell proliferation, differentiation, immune responses, and redox balance. In response to various physiological signals or external stimuli, a sophisticated mitochondrial quality control (MQC) mechanism has evolved, encompassing key processes like mitochondrial biogenesis, mitochondrial dynamics, and mitophagy, which have garnered increasing attention from researchers to unveil their specific molecular mechanisms. In this review, we present a comprehensive summary of the primary mechanisms and functions of key regulators involved in major components of MQC. Furthermore, the critical physiological functions regulated by MQC and its diverse roles in the progression of various systemic diseases have been described in detail. We also discuss agonists or antagonists targeting MQC, aiming to explore potential therapeutic and research prospects by enhancing MQC to stabilize mitochondrial function.
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Affiliation(s)
- Bo-Hao Liu
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
- Department of Thoracic Surgery, First Hospital of Jilin University, Changchun, 130021, China
| | - Chen-Zhen Xu
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Yi Liu
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zi-Long Lu
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Ting-Lv Fu
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Guo-Rui Li
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Yu Deng
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Guo-Qing Luo
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Song Ding
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Ning Li
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China.
| | - Qing Geng
- Department of Thoracic Surgery, Renmin Hospital of Wuhan University, Wuhan, 430060, China.
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3
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Lei Y, Gan M, Qiu Y, Chen Q, Wang X, Liao T, Zhao M, Chen L, Zhang S, Zhao Y, Niu L, Wang Y, Zhu L, Shen L. The role of mitochondrial dynamics and mitophagy in skeletal muscle atrophy: from molecular mechanisms to therapeutic insights. Cell Mol Biol Lett 2024; 29:59. [PMID: 38654156 PMCID: PMC11036639 DOI: 10.1186/s11658-024-00572-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/04/2024] [Indexed: 04/25/2024] Open
Abstract
Skeletal muscle is the largest metabolic organ of the human body. Maintaining the best quality control and functional integrity of mitochondria is essential for the health of skeletal muscle. However, mitochondrial dysfunction characterized by mitochondrial dynamic imbalance and mitophagy disruption can lead to varying degrees of muscle atrophy, but the underlying mechanism of action is still unclear. Although mitochondrial dynamics and mitophagy are two different mitochondrial quality control mechanisms, a large amount of evidence has indicated that they are interrelated and mutually regulated. The former maintains the balance of the mitochondrial network, eliminates damaged or aged mitochondria, and enables cells to survive normally. The latter degrades damaged or aged mitochondria through the lysosomal pathway, ensuring cellular functional health and metabolic homeostasis. Skeletal muscle atrophy is considered an urgent global health issue. Understanding and gaining knowledge about muscle atrophy caused by mitochondrial dysfunction, particularly focusing on mitochondrial dynamics and mitochondrial autophagy, can greatly contribute to the prevention and treatment of muscle atrophy. In this review, we critically summarize the recent research progress on mitochondrial dynamics and mitophagy in skeletal muscle atrophy, and expound on the intrinsic molecular mechanism of skeletal muscle atrophy caused by mitochondrial dynamics and mitophagy. Importantly, we emphasize the potential of targeting mitochondrial dynamics and mitophagy as therapeutic strategies for the prevention and treatment of muscle atrophy, including pharmacological treatment and exercise therapy, and summarize effective methods for the treatment of skeletal muscle atrophy.
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Affiliation(s)
- Yuhang Lei
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Mailin Gan
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yanhao Qiu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Qiuyang Chen
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Xingyu Wang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Tianci Liao
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Mengying Zhao
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Lei Chen
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Shunhua Zhang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Ye Zhao
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Lili Niu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Yan Wang
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China
| | - Li Zhu
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
| | - Linyuan Shen
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, 611130, China.
- Key Laboratory of Livestock and Poultry Multi-Omics, Ministry of Agriculture and Rural Affairs, College of Animal and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
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4
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Gao J, Leinonen H, Wang EJ, Ding M, Perry G, Palczewski K, Wang X. Sex-Specific Early Retinal Dysfunction in Mutant TDP-43 Transgenic Mice. J Alzheimers Dis 2024; 97:927-937. [PMID: 38143367 PMCID: PMC11174142 DOI: 10.3233/jad-231102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2023]
Abstract
BACKGROUND Increasing evidence has highlighted retinal impairments in neurodegenerative diseases. Dominant mutations in TAR DNA-binding protein 43 (TDP-43) cause amyotrophic lateral sclerosis (ALS), and the accumulation of TDP-43 in the cytoplasm is a pathological hallmark of ALS, frontotemporal dementia (FTD), and many other neurodegenerative diseases. OBJECTIVE While homozygous transgenic mice expressing the disease-causing human TDP-43 M337V mutant (TDP-43M337V mice) experience premature death, hemizygous TDP-43M337V mice do not suffer sudden death, but they exhibit age-dependent motor-coordinative and cognitive deficits. This study aims to leverage the hemizygous TDP-43M337V mice as a valuable ALS/FTD disease model for the assessment also of retinal changes during the disease progression. METHODS We evaluated the retinal function of young TDP-43M337V mice by full field electroretinogram (ERG) recordings. RESULTS At 3-4 months of age, well before the onset of brain dysfunction at 8 months, the ERG responses were notably impaired in the retinas of young female TDP-43M337V mice in contrast to their male counterparts and age-matched non-transgenic mice. Mitochondria have been implicated as critical targets of TDP-43. Further investigation revealed that significant changes in the key regulators of mitochondrial dynamics and bioenergetics were only observed in the retinas of young female TDP-43M337V mice, while these alterations were not present in the brains of either gender. CONCLUSIONS Together our findings suggest a sex-specific vulnerability within the retina in the early disease stage, and highlight the importance of retinal changes and mitochondrial markers as potential early diagnostic indicators for ALS, FTD, and other TDP-43 related neurodegenerative conditions.
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Affiliation(s)
- Ju Gao
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA
| | - Henri Leinonen
- School of Pharmacy, University of Eastern Finland, 70211 Kuopio, Finland
| | - Evan J Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Mao Ding
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, UCI, Irvine, CA, USA
- Department of Physiology and Biophysics, Chemistry and Molecular biology and Biochemsitry, UCI, Irvine, CA, USA
| | - Xinglong Wang
- Department of Pharmacology and Toxicology, University of Arizona, Tucson, AZ, USA
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
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5
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Abstract
Neurons are markedly compartmentalized, which makes them reliant on axonal transport to maintain their health. Axonal transport is important for anterograde delivery of newly synthesized macromolecules and organelles from the cell body to the synapse and for the retrograde delivery of signaling endosomes and autophagosomes for degradation. Dysregulation of axonal transport occurs early in neurodegenerative diseases and plays a key role in axonal degeneration. Here, we provide an overview of mechanisms for regulation of axonal transport; discuss how these mechanisms are disrupted in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, hereditary spastic paraplegia, amyotrophic lateral sclerosis, and Charcot-Marie-Tooth disease; and discuss therapeutic approaches targeting axonal transport.
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6
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Qin S, You P, Yu H, Su B. REEP1 Preserves Motor Function in SOD1 G93A Mice by Improving Mitochondrial Function via Interaction with NDUFA4. Neurosci Bull 2023; 39:929-946. [PMID: 36520405 PMCID: PMC10264344 DOI: 10.1007/s12264-022-00995-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 09/25/2022] [Indexed: 12/23/2022] Open
Abstract
A decline in the activities of oxidative phosphorylation (OXPHOS) complexes has been consistently reported in amyotrophic lateral sclerosis (ALS) patients and animal models of ALS, although the underlying molecular mechanisms are still elusive. Here, we report that receptor expression enhancing protein 1 (REEP1) acts as an important regulator of complex IV assembly, which is pivotal to preserving motor neurons in SOD1G93A mice. We found the expression of REEP1 was greatly reduced in transgenic SOD1G93A mice with ALS. Moreover, forced expression of REEP1 in the spinal cord extended the lifespan, decelerated symptom progression, and improved the motor performance of SOD1G93A mice. The neuromuscular synaptic loss, gliosis, and even motor neuron loss in SOD1G93A mice were alleviated by increased REEP1 through augmentation of mitochondrial function. Mechanistically, REEP1 associates with NDUFA4, and plays an important role in preserving the integrity of mitochondrial complex IV. Our findings offer insights into the pathogenic mechanism of REEP1 deficiency in neurodegenerative diseases and suggest a new therapeutic target for ALS.
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Affiliation(s)
- Siyue Qin
- Department of Cell Biology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences, Shandong University, Jinan, 250012, China
| | - Pan You
- Department of Cell Biology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences, Shandong University, Jinan, 250012, China
| | - Hui Yu
- Department of Cell Biology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences, Shandong University, Jinan, 250012, China
| | - Bo Su
- Department of Cell Biology, Shandong Provincial Key Laboratory of Mental Disorders, School of Basic Medical Sciences, Shandong University, Jinan, 250012, China.
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7
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O'Connor K, Spendiff S, Lochmüller H, Horvath R. Mitochondrial Mutations Can Alter Neuromuscular Transmission in Congenital Myasthenic Syndrome and Mitochondrial Disease. Int J Mol Sci 2023; 24:ijms24108505. [PMID: 37239850 DOI: 10.3390/ijms24108505] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023] Open
Abstract
Congenital myasthenic syndromes (CMS) are a group of rare, neuromuscular disorders that usually present in childhood or infancy. While the phenotypic presentation of these disorders is diverse, the unifying feature is a pathomechanism that disrupts neuromuscular transmission. Recently, two mitochondrial genes-SLC25A1 and TEFM-have been reported in patients with suspected CMS, prompting a discussion about the role of mitochondria at the neuromuscular junction (NMJ). Mitochondrial disease and CMS can present with similar symptoms, and potentially one in four patients with mitochondrial myopathy exhibit NMJ defects. This review highlights research indicating the prominent roles of mitochondria at both the pre- and postsynapse, demonstrating the potential for mitochondrial involvement in neuromuscular transmission defects. We propose the establishment of a novel subcategorization for CMS-mitochondrial CMS, due to unifying clinical features and the potential for mitochondrial defects to impede transmission at the pre- and postsynapse. Finally, we highlight the potential of targeting the neuromuscular transmission in mitochondrial disease to improve patient outcomes.
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Affiliation(s)
- Kaela O'Connor
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Centre for Neuromuscular Disease, University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H 8M5, Canada
| | - Sally Spendiff
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON K1H 8L6, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Department of Neuropediatrics and Muscle Disorders, Faculty of Medicine, Medical Center-University of Freiburg, 79104 Freiburg, Germany
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Catalonia, Spain
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge CB3 0FD, UK
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8
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Dorn GW. Reversing Dysdynamism to Interrupt Mitochondrial Degeneration in Amyotrophic Lateral Sclerosis. Cells 2023; 12:1188. [PMID: 37190097 PMCID: PMC10136928 DOI: 10.3390/cells12081188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
Amyotrophic lateral sclerosis is one of several chronic neurodegenerative conditions in which mitochondrial abnormalities are posited to contribute to disease progression. Therapeutic options targeting mitochondria include enhancing metabolism, suppressing reactive oxygen production and disrupting mitochondria-mediated programmed cell death pathways. Herein is reviewed mechanistic evidence supporting a meaningful pathophysiological role for the constellation of abnormal mitochondrial fusion, fission and transport, collectively designated mitochondrial dysdynamism, in ALS. Following this is a discussion on preclinical studies in ALS mice that seemingly validate the idea that normalizing mitochondrial dynamism can delay ALS by interrupting a vicious cycle of mitochondrial degeneration, leading to neuronal die-back and death. Finally, the relative benefits of suppressing mitochondrial fusion vs. enhancing mitochondrial fusion in ALS are speculated upon, and the paper concludes with the prediction that the two approaches could be additive or synergistic, although a side-by-side comparative trial may be challenging to perform.
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Affiliation(s)
- Gerald W Dorn
- Department of Internal Medicine (Pharmacogenomics), Washington University School of Medicine, St. Louis, MO 63110, USA
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9
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Suzuki N, Nishiyama A, Warita H, Aoki M. Genetics of amyotrophic lateral sclerosis: seeking therapeutic targets in the era of gene therapy. J Hum Genet 2023; 68:131-152. [PMID: 35691950 PMCID: PMC9968660 DOI: 10.1038/s10038-022-01055-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/17/2022] [Accepted: 05/29/2022] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an intractable disease that causes respiratory failure leading to mortality. The main locus of ALS is motor neurons. The success of antisense oligonucleotide (ASO) therapy in spinal muscular atrophy (SMA), a motor neuron disease, has triggered a paradigm shift in developing ALS therapies. The causative genes of ALS and disease-modifying genes, including those of sporadic ALS, have been identified one after another. Thus, the freedom of target choice for gene therapy has expanded by ASO strategy, leading to new avenues for therapeutic development. Tofersen for superoxide dismutase 1 (SOD1) was a pioneer in developing ASO for ALS. Improving protocols and devising early interventions for the disease are vital. In this review, we updated the knowledge of causative genes in ALS. We summarized the genetic mutations identified in familial ALS and their clinical features, focusing on SOD1, fused in sarcoma (FUS), and transacting response DNA-binding protein. The frequency of the C9ORF72 mutation is low in Japan, unlike in Europe and the United States, while SOD1 and FUS are more common, indicating that the target mutations for gene therapy vary by ethnicity. A genome-wide association study has revealed disease-modifying genes, which could be the novel target of gene therapy. The current status and prospects of gene therapy development were discussed, including ethical issues. Furthermore, we discussed the potential of axonal pathology as new therapeutic targets of ALS from the perspective of early intervention, including intra-axonal transcription factors, neuromuscular junction disconnection, dysregulated local translation, abnormal protein degradation, mitochondrial pathology, impaired axonal transport, aberrant cytoskeleton, and axon branching. We simultaneously discuss important pathological states of cell bodies: persistent stress granules, disrupted nucleocytoplasmic transport, and cryptic splicing. The development of gene therapy based on the elucidation of disease-modifying genes and early intervention in molecular pathology is expected to become an important therapeutic strategy in ALS.
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Affiliation(s)
- Naoki Suzuki
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan.
| | - Ayumi Nishiyama
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Hitoshi Warita
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan.
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10
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Small molecule agonist of mitochondrial fusion repairs mitochondrial dysfunction. Nat Chem Biol 2023; 19:468-477. [PMID: 36635564 DOI: 10.1038/s41589-022-01224-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 11/14/2022] [Indexed: 01/13/2023]
Abstract
Membrane dynamics are important to the integrity and function of mitochondria. Defective mitochondrial fusion underlies the pathogenesis of multiple diseases. The ability to target fusion highlights the potential to fight life-threatening conditions. Here we report a small molecule agonist, S89, that specifically promotes mitochondrial fusion by targeting endogenous MFN1. S89 interacts directly with a loop region in the helix bundle 2 domain of MFN1 to stimulate GTP hydrolysis and vesicle fusion. GTP loading or competition by S89 dislodges the loop from the GTPase domain and unlocks the molecule. S89 restores mitochondrial and cellular defects caused by mitochondrial DNA mutations, oxidative stress inducer paraquat, ferroptosis inducer RSL3 or CMT2A-causing mutations by boosting endogenous MFN1. Strikingly, S89 effectively eliminates ischemia/reperfusion (I/R)-induced mitochondrial damage and protects mouse heart from I/R injury. These results reveal the priming mechanism for MFNs and provide a therapeutic strategy for mitochondrial diseases when additional mitochondrial fusion is beneficial.
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11
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Huseby CJ, Delvaux E, Brokaw DL, Coleman PD. Blood RNA transcripts reveal similar and differential alterations in fundamental cellular processes in Alzheimer's disease and other neurodegenerative diseases. Alzheimers Dement 2022. [DOI: 10.1002/alz.12880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/30/2022] [Accepted: 10/21/2022] [Indexed: 12/24/2022]
Affiliation(s)
- Carol J. Huseby
- ASU‐Banner Neurodegenerative Disease Research Center Arizona State University Tempe Arizona USA
| | - Elaine Delvaux
- ASU‐Banner Neurodegenerative Disease Research Center Arizona State University Tempe Arizona USA
| | - Danielle L. Brokaw
- University of Pennsylvania Perelman School of Medicine Philadelphia Pennsylvania USA
| | - Paul D. Coleman
- ASU‐Banner Neurodegenerative Disease Research Center Arizona State University Tempe Arizona USA
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12
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Miller JA, Drouet DE, Yermakov LM, Elbasiouny MS, Bensabeur FZ, Bottomley M, Susuki K. Distinct Changes in Calpain and Calpastatin during PNS Myelination and Demyelination in Rodent Models. Int J Mol Sci 2022; 23:15443. [PMID: 36499770 PMCID: PMC9737575 DOI: 10.3390/ijms232315443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 11/19/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022] Open
Abstract
Myelin forming around axons provides electrical insulation and ensures rapid and efficient transmission of electrical impulses. Disruptions to myelinated nerves often result in nerve conduction failure along with neurological symptoms and long-term disability. In the central nervous system, calpains, a family of calcium dependent cysteine proteases, have been shown to have a role in developmental myelination and in demyelinating diseases. The roles of calpains in myelination and demyelination in the peripheral nervous system remain unclear. Here, we show a transient increase of activated CAPN1, a major calpain isoform, in postnatal rat sciatic nerves when myelin is actively formed. Expression of the endogenous calpain inhibitor, calpastatin, showed a steady decrease throughout the period of peripheral nerve development. In the sciatic nerves of Trembler-J mice characterized by dysmyelination, expression levels of CAPN1 and calpastatin and calpain activity were significantly increased. In lysolecithin-induced acute demyelination in adult rat sciatic nerves, we show an increase of CAPN1 and decrease of calpastatin expression. These changes in the calpain-calpastatin system are distinct from those during central nervous system development or in acute axonal degeneration in peripheral nerves. Our results suggest that the calpain-calpastatin system has putative roles in myelination and demyelinating diseases of peripheral nerves.
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Affiliation(s)
- John A. Miller
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Domenica E. Drouet
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Leonid M. Yermakov
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Mahmoud S. Elbasiouny
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Fatima Z. Bensabeur
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Michael Bottomley
- Department of Mathematics and Statistics, Wright State University, Dayton, OH 45435, USA
| | - Keiichiro Susuki
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
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13
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Zilio E, Piano V, Wirth B. Mitochondrial Dysfunction in Spinal Muscular Atrophy. Int J Mol Sci 2022; 23:10878. [PMID: 36142791 PMCID: PMC9503857 DOI: 10.3390/ijms231810878] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating neuromuscular disorder caused by recessive mutations in the SMN1 gene, globally affecting ~8-14 newborns per 100,000. The severity of the disease depends on the residual levels of functional survival of motor neuron protein, SMN. SMN is a ubiquitously expressed RNA binding protein involved in a plethora of cellular processes. In this review, we discuss the effects of SMN loss on mitochondrial functions in the neuronal and muscular systems that are the most affected in patients with spinal muscular atrophy. Our aim is to highlight how mitochondrial defects may contribute to disease progression and how restoring mitochondrial functionality may be a promising approach to develop new therapies. We also collected from previous studies a list of transcripts encoding mitochondrial proteins affected in various SMA models. Moreover, we speculate that in adulthood, when motor neurons require only very low SMN levels, the natural deterioration of mitochondria associated with aging may be a crucial triggering factor for adult spinal muscular atrophy, and this requires particular attention for therapeutic strategies.
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Affiliation(s)
- Eleonora Zilio
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Valentina Piano
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Institute for Genetics, University of Cologne, 50674 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
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14
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Liao Z, Xiao M, Chen J, Yang Y, Lyu Q, Zhou J, Sun Y, Zhao Y, Fan Z, Yu J, Wu Y, Chen Q, Wu J, Xiao Q. CHRNA1 induced sarcopenia through neuromuscular synaptic elimination. Exp Gerontol 2022; 166:111891. [PMID: 35809807 DOI: 10.1016/j.exger.2022.111891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/25/2022] [Accepted: 07/04/2022] [Indexed: 11/04/2022]
Abstract
Sarcopenia seriously affects the quality of life of the elderly, but its molecular mechanism is still unclear. Degeneration in muscle innervation is related to age-related movement disorders and muscle atrophy. The expression of CHRNA1 is increased in the skeletal muscle of the elderly, and in aging rodents. Therefore, we investigated whether CHRNA1 induces the occurrence and development of sarcopenia. Compared with the control group, local injection of AAV9-CHRNA1 into the hindlimb muscles decreased the percentage of muscle innervation. At the same time, the skeletal muscle mass decreased, as manifested by a decrease in the gastrocnemius mass index and the cross-sectional area of the muscle fibers. The function of skeletal muscle also decreased, which was manifested by decreases of compound muscle action potential and muscle contractility. Therefore, we concluded that upregulation of CHRNA1 can induce and aggravate sarcopenia.
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Affiliation(s)
- Zhiyin Liao
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Minghan Xiao
- Department of Cardiology, University of Chinese Academy of Sciences, No. 118, Xingguang Avenue, Liangjiang New Area, 401147 Chongqing, China
| | - Jinliang Chen
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Yunfei Yang
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Qiong Lyu
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Jing Zhou
- Department of Clinic, Chongqing Medical And Pharmaceutical College, No. 82, University Town Middle Road, Shapingba District, 401331 Chongqing, China
| | - Yue Sun
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Yuxing Zhao
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Zhen Fan
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Jing Yu
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Yongxin Wu
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Qiunan Chen
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Jianghao Wu
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China
| | - Qian Xiao
- Department of Geriatrics, the First Affiliated Hospital of Chongqing Medical University, Friendship Road 1, Yuan Jiagang, 400016 Chongqing, China.
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15
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Nikolaeva NS, Yandulova EY, Aleksandrova YR, Starikov AS, Neganova ME. The Role of a Pathological Interaction between β-amyloid and Mitochondria in the Occurrence and Development of Alzheimer's Disease. Acta Naturae 2022; 14:19-34. [PMID: 36348714 PMCID: PMC9611857 DOI: 10.32607/actanaturae.11723] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/05/2022] [Indexed: 11/20/2022] Open
Abstract
Alzheimer's disease (AD) is one of the most common neurodegenerative diseases in existence. It is characterized by an impaired cognitive function that is due to a progressive loss of neurons in the brain. Extracellular β-amyloid (Aβ) plaques are the main pathological features of the disease. In addition to abnormal protein aggregation, increased mitochondrial fragmentation, altered expression of the genes involved in mitochondrial biogenesis, disruptions in the ER-mitochondria interaction, and mitophagy are observed. Reactive oxygen species are known to affect Aβ expression and aggregation. In turn, oligomeric and aggregated Aβ cause mitochondrial disorders. In this review, we summarize available knowledge about the pathological effects of Aβ on mitochondria and the potential molecular targets associated with proteinopathy and mitochondrial dysfunction for the pharmacological treatment of Alzheimer's disease.
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Affiliation(s)
- N. S. Nikolaeva
- Federal State Budgetary Institution of Science Institute of Physiologically Active Compounds of the Russian Academy of Sciences, Chernogolovka, 142432 Russia
| | - E. Yu. Yandulova
- Federal State Budgetary Institution of Science Institute of Physiologically Active Compounds of the Russian Academy of Sciences, Chernogolovka, 142432 Russia
| | - Yu. R. Aleksandrova
- Federal State Budgetary Institution of Science Institute of Physiologically Active Compounds of the Russian Academy of Sciences, Chernogolovka, 142432 Russia
| | - A. S. Starikov
- Federal State Budgetary Institution of Science Institute of Physiologically Active Compounds of the Russian Academy of Sciences, Chernogolovka, 142432 Russia
| | - M. E. Neganova
- Federal State Budgetary Institution of Science Institute of Physiologically Active Compounds of the Russian Academy of Sciences, Chernogolovka, 142432 Russia
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16
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Piperine Derivatives Enhance Fusion and Axonal Transport of Mitochondria by Activating Mitofusins. CHEMISTRY 2022. [DOI: 10.3390/chemistry4030047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Piperine (1-piperoylpiperidine) is the major pungent component of black pepper (Piper nigrum) and exhibits a spectrum of pharmacological activities. The molecular bases for many of piperine’s biological effects are incompletely defined. We noted that the chemical structure of piperine generally conforms to a pharmacophore model for small bioactive molecules that activate mitofusin (MFN)-mediated mitochondrial fusion. Piperine, but not its isomer chavicine, stimulated mitochondrial fusion in MFN-deficient cells with EC50 of ~8 nM. We synthesized piperine analogs having structural features predicted to optimize mitofusin activation and defined structure-activity relationships (SAR) in live-cell mitochondrial elongation assays. When optimal spacing was maintained between amide and aromatic groups the derivatives were potent mitofusin activators. Compared to the prototype phenylhexanamide mitofusin activator, 2, novel molecules containing the piperidine structure of piperine exhibited markedly enhanced passive membrane permeability with no loss of fusogenic potency. Lead compounds 5 and 8 enhanced mitochondrial motility in cultured murine Charcot-Marie-Tooth disease type 2A (CMT2A) neurons, but only 8 improved mitochondrial transport in sciatic nerve axons of CMT2A mice. Piperine analogs represent a new chemical class of mitofusin activators with potential pharmaceutical advantages.
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17
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Rai M, Curley M, Coleman Z, Demontis F. Contribution of proteases to the hallmarks of aging and to age-related neurodegeneration. Aging Cell 2022; 21:e13603. [PMID: 35349763 PMCID: PMC9124314 DOI: 10.1111/acel.13603] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/10/2022] [Accepted: 03/13/2022] [Indexed: 12/20/2022] Open
Abstract
Protein quality control ensures the degradation of damaged and misfolded proteins. Derangement of proteostasis is a primary cause of aging and age-associated diseases. The ubiquitin-proteasome and autophagy-lysosome play key roles in proteostasis but, in addition to these systems, the human genome encodes for ~600 proteases, also known as peptidases. Here, we examine the role of proteases in aging and age-related neurodegeneration. Proteases are present across cell compartments, including the extracellular space, and their substrates encompass cellular constituents, proteins with signaling functions, and misfolded proteins. Proteolytic processing by proteases can lead to changes in the activity and localization of substrates or to their degradation. Proteases cooperate with the autophagy-lysosome and ubiquitin-proteasome systems but also have independent proteolytic roles that impact all hallmarks of cellular aging. Specifically, proteases regulate mitochondrial function, DNA damage repair, cellular senescence, nutrient sensing, stem cell properties and regeneration, protein quality control and stress responses, and intercellular signaling. The capacity of proteases to regulate cellular functions translates into important roles in preserving tissue homeostasis during aging. Consequently, proteases influence the onset and progression of age-related pathologies and are important determinants of health span. Specifically, we examine how certain proteases promote the progression of Alzheimer's, Huntington's, and/or Parkinson's disease whereas other proteases protect from neurodegeneration. Mechanistically, cleavage by proteases can lead to the degradation of a pathogenic protein and hence impede disease pathogenesis. Alternatively, proteases can generate substrate byproducts with increased toxicity, which promote disease progression. Altogether, these studies indicate the importance of proteases in aging and age-related neurodegeneration.
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Affiliation(s)
- Mamta Rai
- Department of Developmental NeurobiologySt. Jude Children’s Research HospitalMemphisTennesseeUSA
| | - Michelle Curley
- Department of Developmental NeurobiologySt. Jude Children’s Research HospitalMemphisTennesseeUSA
| | - Zane Coleman
- Department of Developmental NeurobiologySt. Jude Children’s Research HospitalMemphisTennesseeUSA
| | - Fabio Demontis
- Department of Developmental NeurobiologySt. Jude Children’s Research HospitalMemphisTennesseeUSA
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18
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Liu D, Fan YB, Tao XH, Pan WL, Wu YX, Wang XH, He YQ, Xiao WF, Li YS. Mitochondrial Quality Control in Sarcopenia: Updated Overview of Mechanisms and Interventions. Aging Dis 2021; 12:2016-2030. [PMID: 34881083 PMCID: PMC8612607 DOI: 10.14336/ad.2021.0427] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/27/2021] [Indexed: 12/22/2022] Open
Abstract
Sarcopenia is a common geriatric disorder characterized by decreased muscle strength, low muscle mass and poor physical performance. This aging-related skeletal muscle deterioration leads to adverse outcomes and severely impairs the quality of life of patients. The accumulation of dysfunctional mitochondria with aging is an important factor in the occurrence and progression of sarcopenia. Mitochondrial quality control (MQC) fundamentally ensures the normal mitochondrial functions and is comprised of four main parts: proteostasis, biogenesis, dynamics and autophagy. Therefore, any pathophysiologic factors compromising the quality control of homeostasis in the skeletal muscle may lead to sarcopenia. However, the specific theoretical aspects of these processes have not been fully elucidated. Current therapeutic interventions using nutritional and pharmaceutical treatments show a modest therapeutic efficacy; however, only physical exercise is recommended as the first-line therapy for sarcopenia, which can ameliorate skeletal muscle deficiency by maintaining the homeostatic MQC. In this review, we summarized the known mechanisms that contribute to the pathogenesis of sarcopenia by impairing normal mitochondrial functions and described potential interventions that mitigate sarcopenia through improving MQC.
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Affiliation(s)
- Di Liu
- 1Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Yi-Bin Fan
- 2Department of Dermatology, Zhejiang provincial people's hospital, People's Hospital of Hangzhou Medical College, Hangzhou 310014, China
| | - Xiao-Hua Tao
- 2Department of Dermatology, Zhejiang provincial people's hospital, People's Hospital of Hangzhou Medical College, Hangzhou 310014, China
| | - Wei-Li Pan
- 2Department of Dermatology, Zhejiang provincial people's hospital, People's Hospital of Hangzhou Medical College, Hangzhou 310014, China
| | - Yu-Xiang Wu
- 3School of Kinesiology, Jianghan University, Wuhan 430056, China
| | - Xiu-Hua Wang
- 4Xiang Ya Nursing School, The Central South University, Changsha 410013, China
| | - Yu-Qiong He
- 1Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Wen-Feng Xiao
- 1Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China.,5National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
| | - Yu-Sheng Li
- 1Department of Orthopaedics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China.,5National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha 410008, Hunan, China
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19
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Ziegler DV, Martin N, Bernard D. Cellular senescence links mitochondria-ER contacts and aging. Commun Biol 2021; 4:1323. [PMID: 34819602 PMCID: PMC8613202 DOI: 10.1038/s42003-021-02840-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/30/2021] [Indexed: 12/11/2022] Open
Abstract
Membrane contact sites emerged in the last decade as key players in the integration, regulation and transmission of many signals within cells, with critical impact in multiple pathophysiological contexts. Numerous studies accordingly point to a role for mitochondria-endoplasmic reticulum contacts (MERCs) in modulating aging. Nonetheless, the driving cellular mechanisms behind this role remain unclear. Recent evidence unravelled that MERCs regulate cellular senescence, a state of permanent proliferation arrest associated with a pro-inflammatory secretome, which could mediate MERC impact on aging. Here we discuss this idea in light of recent advances supporting an interplay between MERCs, cellular senescence and aging.
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Affiliation(s)
- Dorian V Ziegler
- Centre de Recherche en Cancérologie de Lyon, Inserm U1052, CNRS UMR 5286, Université de Lyon, Centre Léon Bérard, Lyon, France.
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.
| | - Nadine Martin
- Centre de Recherche en Cancérologie de Lyon, Inserm U1052, CNRS UMR 5286, Université de Lyon, Centre Léon Bérard, Lyon, France.
| | - David Bernard
- Centre de Recherche en Cancérologie de Lyon, Inserm U1052, CNRS UMR 5286, Université de Lyon, Centre Léon Bérard, Lyon, France.
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20
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Hu D, Liu Z, Qi X. Mitochondrial Quality Control Strategies: Potential Therapeutic Targets for Neurodegenerative Diseases? Front Neurosci 2021; 15:746873. [PMID: 34867159 PMCID: PMC8633545 DOI: 10.3389/fnins.2021.746873] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 10/19/2021] [Indexed: 12/30/2022] Open
Abstract
Many lines of evidence have indicated the therapeutic potential of rescuing mitochondrial integrity by targeting specific mitochondrial quality control pathways in neurodegenerative diseases, such as Parkinson's disease, Huntington's disease, and Alzheimer's disease. In addition to ATP synthesis, mitochondria are critical regulators of ROS production, lipid metabolism, calcium buffering, and cell death. The mitochondrial unfolded protein response, mitochondrial dynamics, and mitophagy are the three main quality control mechanisms responsible for maintaining mitochondrial proteostasis and bioenergetics. The proper functioning of these complex processes is necessary to surveil and restore mitochondrial homeostasis and the healthy pool of mitochondria in cells. Mitochondrial dysfunction occurs early and causally in disease pathogenesis. A significant accumulation of mitochondrial damage resulting from compromised quality control pathways leads to the development of neuropathology. Moreover, genetic or pharmaceutical manipulation targeting the mitochondrial quality control mechanisms can sufficiently rescue mitochondrial integrity and ameliorate disease progression. Thus, therapies that can improve mitochondrial quality control have great promise for the treatment of neurodegenerative diseases. In this review, we summarize recent progress in the field that underscores the essential role of impaired mitochondrial quality control pathways in the pathogenesis of neurodegenerative diseases. We also discuss the translational approaches targeting mitochondrial function, with a focus on the restoration of mitochondrial integrity, including mitochondrial dynamics, mitophagy, and mitochondrial proteostasis.
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Affiliation(s)
- Di Hu
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Zunren Liu
- Department of Biology, College of Arts and Sciences, Case Western Reserve University, Cleveland, OH, United States
| | - Xin Qi
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
- Center for Mitochondrial Disease, Case Western Reserve University School of Medicine, Cleveland, OH, United States
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21
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Dang X, Williams SB, Devanathan S, Franco A, Fu L, Bernstein PR, Walters D, Dorn GW. Pharmacophore-Based Design of Phenyl-[hydroxycyclohexyl] Cycloalkyl-Carboxamide Mitofusin Activators with Improved Neuronal Activity. J Med Chem 2021; 64:12506-12524. [PMID: 34415150 DOI: 10.1021/acs.jmedchem.1c00163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mitochondrial fragmentation from defective fusion or unopposed fission contributes to many neurodegenerative diseases. Small molecule mitofusin activators reverse mitochondrial fragmentation in vitro, promising a novel therapeutic approach. The first-in-class mitofusin activator, 2, has a short plasma t1/2 and limited neurological system bioavailability, conferring "burst activation". Here, pharmacophore-based rational redesign generated analogues of 2 incorporating cycloalkyl linker groups. A cyclopropyl-containing linker, 5, improved plasma and brain t1/2, increased nervous system bioavailability, and prolonged neuron pharmacodynamic effects. Functional and single-crystal X-ray diffraction studies of stereoisomeric analogues of 5 containing sulfur as a "heavy atom", 14A and 14B, showed that 5 biological activity resides in the trans-R/R configuration, 5B. Structural analysis revealed stereoselective interactions of 5 associated with its mimicry of MFN2 Val372, Met376, and His380 side chains. Modification of murine ALS phenotypes in vitro and in vivo supports advancement of 5B for neurological conditions that may benefit from sustained mitofusin activation.
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Affiliation(s)
- Xiawei Dang
- Department of Cardiology, The First Affiliated Hospital of Xi'an Jiao Tong University, Xi'an, Shaanxi 710061, China.,Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Sidney B Williams
- Mitochondria in Motion, Inc., 4340 Duncan Avenue, Suite 216, St. Louis, Missouri 63110, United States
| | - Sriram Devanathan
- Mitochondria in Motion, Inc., 4340 Duncan Avenue, Suite 216, St. Louis, Missouri 63110, United States
| | - Antonietta Franco
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Lijun Fu
- WuXi AppTec Co., Ltd., 666 Gaoxin Road, East Lake High-tech Development Zone, Wuhan, Hubei 430075, China
| | - Peter R Bernstein
- PharmaB LLC, 50 S. 16th Street, Unit 5201, Philadelphia, Pennsylvania 19102, United States
| | - Daniel Walters
- Crystal Pharmatech Inc., 3000 Eastpark Blvd., Ste 500B, Cranbury, New Jersey 08512, United States
| | - Gerald W Dorn
- Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, United States.,Mitochondria in Motion, Inc., 4340 Duncan Avenue, Suite 216, St. Louis, Missouri 63110, United States
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22
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Small-molecule suppression of calpastatin degradation reduces neuropathology in models of Huntington's disease. Nat Commun 2021; 12:5305. [PMID: 34489447 PMCID: PMC8421361 DOI: 10.1038/s41467-021-25651-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 08/19/2021] [Indexed: 11/08/2022] Open
Abstract
Mitochondrial dysfunction is a common hallmark of neurological disorders, and reducing mitochondrial damage is considered a promising neuroprotective therapeutic strategy. Here, we used high-throughput small molecule screening to identify CHIR99021 as a potent enhancer of mitochondrial function. CHIR99021 improved mitochondrial phenotypes and enhanced cell viability in several models of Huntington’s disease (HD), a fatal inherited neurodegenerative disorder. Notably, CHIR99201 treatment reduced HD-associated neuropathology and behavioral defects in HD mice and improved mitochondrial function and cell survival in HD patient-derived neurons. Independent of its known inhibitory activity against glycogen synthase kinase 3 (GSK3), CHIR99021 treatment in HD models suppressed the proteasomal degradation of calpastatin (CAST), and subsequently inhibited calpain activation, a well-established effector of neural death, and Drp1, a driver of mitochondrial fragmentation. Our results established CAST-Drp1 as a druggable signaling axis in HD pathogenesis and highlighted CHIR99021 as a mitochondrial function enhancer and a potential lead for developing HD therapies. Mitochondrial dysfunction is a common hallmark of neurological disorders. Here, the authors identify CHIR99021 as a potent enhancer of mitochondrial function, which improved mitochondrial phenotypes in Huntington’s disease models. CHIR99021 was shown to stabilize calpastatin, which suppressed calpain activation and Drp1-induced mitochondrial fragmentation.
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23
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Abstract
Mitochondria are organelles with vital functions in almost all eukaryotic cells. Often described as the cellular 'powerhouses' due to their essential role in aerobic oxidative phosphorylation, mitochondria perform many other essential functions beyond energy production. As signaling organelles, mitochondria communicate with the nucleus and other organelles to help maintain cellular homeostasis, allow cellular adaptation to diverse stresses, and help steer cell fate decisions during development. Mitochondria have taken center stage in the research of normal and pathological processes, including normal tissue homeostasis and metabolism, neurodegeneration, immunity and infectious diseases. The central role that mitochondria assume within cells is evidenced by the broad impact of mitochondrial diseases, caused by defects in either mitochondrial or nuclear genes encoding for mitochondrial proteins, on different organ systems. In this Review, we will provide the reader with a foundation of the mitochondrial 'hardware', the mitochondrion itself, with its specific dynamics, quality control mechanisms and cross-organelle communication, including its roles as a driver of an innate immune response, all with a focus on development, disease and aging. We will further discuss how mitochondrial DNA is inherited, how its mutation affects cell and organismal fitness, and current therapeutic approaches for mitochondrial diseases in both model organisms and humans.
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Affiliation(s)
- Marlies P. Rossmann
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Sonia M. Dubois
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Suneet Agarwal
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Leonard I. Zon
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 01238, USA
- Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA 02115, USA
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24
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Kim YM, Krantz S, Jambusaria A, Toth PT, Moon HG, Gunarathna I, Park GY, Rehman J. Mitofusin-2 stabilizes adherens junctions and suppresses endothelial inflammation via modulation of β-catenin signaling. Nat Commun 2021; 12:2736. [PMID: 33980844 PMCID: PMC8115264 DOI: 10.1038/s41467-021-23047-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 04/13/2021] [Indexed: 01/19/2023] Open
Abstract
Endothelial barrier integrity is ensured by the stability of the adherens junction (AJ) complexes comprised of vascular endothelial (VE)-cadherin as well as accessory proteins such as β-catenin and p120-catenin. Disruption of the endothelial barrier due to disassembly of AJs results in tissue edema and the influx of inflammatory cells. Using three-dimensional structured illumination microscopy, we observe that the mitochondrial protein Mitofusin-2 (Mfn2) co-localizes at the plasma membrane with VE-cadherin and β-catenin in endothelial cells during homeostasis. Upon inflammatory stimulation, Mfn2 is sulfenylated, the Mfn2/β-catenin complex disassociates from the AJs and Mfn2 accumulates in the nucleus where Mfn2 negatively regulates the transcriptional activity of β-catenin. Endothelial-specific deletion of Mfn2 results in inflammatory activation, indicating an anti-inflammatory role of Mfn2 in vivo. Our results suggest that Mfn2 acts in a non-canonical manner to suppress the inflammatory response by stabilizing cell-cell adherens junctions and by binding to the transcriptional activator β-catenin.
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Affiliation(s)
- Young-Mee Kim
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA.
- University of Illinois Cancer Center, University of Illinois at Chicago, Chicago, IL, USA.
| | - Sarah Krantz
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Ankit Jambusaria
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Peter T Toth
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Research Resources Center, University of Illinois at Chicago, Chicago, IL, USA
| | - Hyung-Geun Moon
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Isuru Gunarathna
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Gye Young Park
- Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Jalees Rehman
- Division of Cardiology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
- Department of Pharmacology and Regenerative Medicine, University of Illinois at Chicago, Chicago, IL, USA.
- University of Illinois Cancer Center, University of Illinois at Chicago, Chicago, IL, USA.
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA.
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25
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Effects of Resistance Training on the Redox Status of Skeletal Muscle in Older Adults. Antioxidants (Basel) 2021; 10:antiox10030350. [PMID: 33652958 PMCID: PMC7996821 DOI: 10.3390/antiox10030350] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 12/23/2022] Open
Abstract
The aim of this study was to investigate the effects of resistance training (RT) on the redox status of skeletal muscle in older adults. Thirteen males aged 64 ± 9 years performed full-body RT 2x/week for 6 weeks. Muscle biopsies were obtained from the vastus lateralis prior to and following RT. The mRNA, protein, and enzymatic activity levels of various endogenous antioxidants were determined. In addition, skeletal muscle 4-hydroxynonenal and protein carbonyls were determined as markers of oxidative damage. Protein levels of heat shock proteins (HSPs) were also quantified. RT increased mRNA levels of all assayed antioxidant genes, albeit protein levels either did not change or decreased. RT increased total antioxidant capacity, catalase, and glutathione reductase activities, and decreased glutathione peroxidase activity. Lipid peroxidation also decreased and HSP60 protein increased following RT. In summary, 6 weeks of RT decreased oxidative damage and increased antioxidant enzyme activities. Our results suggest the older adult responses to RT involve multi-level (transcriptional, post-transcriptional, and post-translational) control of the redox status of skeletal muscle.
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26
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Wang L, Liu M, Gao J, Smith AM, Fujioka H, Liang J, Perry G, Wang X. Mitochondrial Fusion Suppresses Tau Pathology-Induced Neurodegeneration and Cognitive Decline. J Alzheimers Dis 2021; 84:1057-1069. [PMID: 34602490 PMCID: PMC9354499 DOI: 10.3233/jad-215175] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Abnormalities of mitochondrial fission and fusion, dynamic processes known to be essential for various aspects of mitochondrial function, have repeatedly been reported to be altered in Alzheimer's disease (AD). Neurofibrillary tangles are known as a hallmark feature of AD and are commonly considered a likely cause of neurodegeneration in this devastating disease. OBJECTIVE To understand the pathological role of mitochondrial dynamics in the context of tauopathy. METHODS The widely used P301S transgenic mice of tauopathy (P301S mice) were crossed with transgenic TMFN mice with the forced expression of Mfn2 specifically in neurons to obtain double transgenic P301S/TMFN mice. Brain tissues from 11-month-old non-transgenic (NTG), TMFN, P301S, and P301S/TMFN mice were analyzed by electron microscopy, confocal microscopy, immunoblot, histological staining, and immunostaining for mitochondria, tau pathology, and tau pathology-induced neurodegeneration and gliosis. The cognitive function was assessed by the Barnes maze. RESULTS P301S mice exhibited mitochondrial fragmentation and a consistent decrease in Mfn2 compared to age-matched NTG mice. When P301S mice were crossed with TMFN mice (P301S/TMFN mice), neuronal loss, as well as mitochondria fragmentation were significantly attenuated. Greatly alleviated tau hyperphosphorylation, filamentous aggregates, and thioflavin-S positive tangles were also noted in P301S/TMFN mice. Furthermore, P301S/TMFN mice showed marked suppression of neuroinflammation and improved cognitive performance in contrast to P301S mice. CONCLUSION These in vivo findings suggest that promoted mitochondrial fusion suppresses toxic tau accumulation and associated neurodegeneration, which may protect against the progression of AD and related tauopathies.
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Affiliation(s)
- Luwen Wang
- Department of Pharmacology and Experimental Neurosciences, University of Nebraska Medical Centre, Omaha, NE, USA
| | - Mengyu Liu
- Departments of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Ju Gao
- Department of Pharmacology and Experimental Neurosciences, University of Nebraska Medical Centre, Omaha, NE, USA
| | - Amber M. Smith
- Departments of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Hisashi Fujioka
- Electron Microscopy Core Facility, Case Western Reserve University, Cleveland, OH, USA
| | - Jingjing Liang
- Departments of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, Texas, USA
| | - Xinglong Wang
- Department of Pharmacology and Experimental Neurosciences, University of Nebraska Medical Centre, Omaha, NE, USA
- Departments of Pathology, Case Western Reserve University, Cleveland, OH, USA
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27
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Hamrick MW, Stranahan AM. Metabolic regulation of aging and age-related disease. Ageing Res Rev 2020; 64:101175. [PMID: 32971259 DOI: 10.1016/j.arr.2020.101175] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 08/19/2020] [Accepted: 09/03/2020] [Indexed: 12/23/2022]
Abstract
Inquiry into relationships between energy metabolism and brain function requires a uniquely interdisciplinary mindset, and implementation of anti-aging lifestyle strategies based on this work also involves consistent mental and physical discipline. Dr. Mark P. Mattson embodies both of these qualities, based on the breadth and depth of his work on neurobiological responses to energetic stress, and on his own diligent practice of regular exercise and caloric restriction. Dr. Mattson created a neurotrophic niche in his own laboratory, allowing trainees to grow their skills, form new connections, and eventually migrate, forming their own labs while remaining part of the extended lab family. In this historical review, we highlight Dr. Mattson's many contributions to understanding neurobiological responses to physical exercise and dietary restriction, with an emphasis on the mechanisms that may underlie neuroprotection in ageing and age-related disease. On the occasion of Dr. Mattson's retirement from the National Institute on Aging, we highlight his foundational work on metabolism and neuroplasticity by reviewing the context for these findings and considering their impact on future research on the neuroscience of aging.
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28
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Murata D, Arai K, Iijima M, Sesaki H. Mitochondrial division, fusion and degradation. J Biochem 2020; 167:233-241. [PMID: 31800050 DOI: 10.1093/jb/mvz106] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 11/17/2019] [Indexed: 12/11/2022] Open
Abstract
The mitochondrion is an essential organelle for a wide range of cellular processes, including energy production, metabolism, signal transduction and cell death. To execute these functions, mitochondria regulate their size, number, morphology and distribution in cells via mitochondrial division and fusion. In addition, mitochondrial division and fusion control the autophagic degradation of dysfunctional mitochondria to maintain a healthy population. Defects in these dynamic membrane processes are linked to many human diseases that include metabolic syndrome, myopathy and neurodegenerative disorders. In the last several years, our fundamental understanding of mitochondrial fusion, division and degradation has been significantly advanced by high resolution structural analyses, protein-lipid biochemistry, super resolution microscopy and in vivo analyses using animal models. Here, we summarize and discuss this exciting recent progress in the mechanism and function of mitochondrial division and fusion.
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Affiliation(s)
- Daisuke Murata
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
| | - Kenta Arai
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
| | - Miho Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
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29
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Liu M, Wang L, Gao J, Dong Q, Perry G, Ma X, Wang X. Inhibition of Calpain Protects Against Tauopathy in Transgenic P301S Tau Mice. J Alzheimers Dis 2020; 69:1077-1087. [PMID: 31156179 DOI: 10.3233/jad-190281] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Alzheimer's disease (AD) and other tauopathies are characterized by intracellular accumulation of microtubule-associated tau protein leading to neurodegeneration. Calpastatin is the endogenous inhibitor of calpain, a calcium-dependent cysteine protease that has been increasingly implicated in tauopathies. In this study, we generated a neuron specific calpastatin overexpressing knock-in transgenic mouse model and crossed it with the PS19 tauopathy mouse model expressing human P301S mutant tau protein. The forced expression of calpastatin in neurons significantly alleviated tau hyperphosphorylation measured by immunocytochemistry and immunoblot. The genetic inhibition of calpain by calpastatin also greatly suppressed characteristic hippocampal neuron loss and widespread astrogliosis and microgliosis in PS19 mice. Consistently, PS19 mice with neuronal calpastatin overexpression exhibited remarkably alleviated cognitive deficits, muscle weakness, skeletal muscle atrophy, and neuromuscular denervation, together implying the neuroprotective effects of neuronal calpastatin in PS19 mice of tauopathy. In sum, this study provides additional evidence supporting the pathological role of calpain in neurodegenerative diseases associated with tau pathology, and suggests that targeting calpain is likely a promising therapeutic approach for these devastating diseases.
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Affiliation(s)
- Mengyu Liu
- College of Life Science and Bio-engineering, Beijing University of Technology, Beijing, China.,Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Luwen Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Ju Gao
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Qing Dong
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Xuemei Ma
- College of Life Science and Bio-engineering, Beijing University of Technology, Beijing, China
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA.,Center for Mitochondrial Diseases, Case Western Reserve University, Cleveland, OH, USA
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30
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Magalhães Rebelo AP, Dal Bello F, Knedlik T, Kaar N, Volpin F, Shin SH, Giacomello M. Chemical Modulation of Mitochondria-Endoplasmic Reticulum Contact Sites. Cells 2020; 9:cells9071637. [PMID: 32646031 PMCID: PMC7408517 DOI: 10.3390/cells9071637] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/23/2020] [Accepted: 07/02/2020] [Indexed: 12/13/2022] Open
Abstract
Contact sites between mitochondria and endoplasmic reticulum (ER) are points in which the two organelles are in close proximity. Due to their structural and functional complexity, their exploitation as pharmacological targets has never been considered so far. Notwithstanding, the number of compounds described to target proteins residing at these interfaces either directly or indirectly is rising. Here we provide original insight into mitochondria–ER contact sites (MERCs), with a comprehensive overview of the current MERCs pharmacology. Importantly, we discuss the considerable potential of MERCs to become a druggable target for the development of novel therapeutic strategies.
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Affiliation(s)
- Ana Paula Magalhães Rebelo
- Department of Biology, University of Padua, Via U. Bassi 58/B, 35121 Padua, Italy; (A.P.M.R.); (F.D.B.); (T.K.); (N.K.); (F.V.); (S.H.S.)
| | - Federica Dal Bello
- Department of Biology, University of Padua, Via U. Bassi 58/B, 35121 Padua, Italy; (A.P.M.R.); (F.D.B.); (T.K.); (N.K.); (F.V.); (S.H.S.)
| | - Tomas Knedlik
- Department of Biology, University of Padua, Via U. Bassi 58/B, 35121 Padua, Italy; (A.P.M.R.); (F.D.B.); (T.K.); (N.K.); (F.V.); (S.H.S.)
| | - Natasha Kaar
- Department of Biology, University of Padua, Via U. Bassi 58/B, 35121 Padua, Italy; (A.P.M.R.); (F.D.B.); (T.K.); (N.K.); (F.V.); (S.H.S.)
| | - Fabio Volpin
- Department of Biology, University of Padua, Via U. Bassi 58/B, 35121 Padua, Italy; (A.P.M.R.); (F.D.B.); (T.K.); (N.K.); (F.V.); (S.H.S.)
| | - Sang Hun Shin
- Department of Biology, University of Padua, Via U. Bassi 58/B, 35121 Padua, Italy; (A.P.M.R.); (F.D.B.); (T.K.); (N.K.); (F.V.); (S.H.S.)
| | - Marta Giacomello
- Department of Biology, University of Padua, Via U. Bassi 58/B, 35121 Padua, Italy; (A.P.M.R.); (F.D.B.); (T.K.); (N.K.); (F.V.); (S.H.S.)
- Department of Biomedical Sciences, University of Padua, Via U. Bassi 58/B, 35121 Padua, Italy
- Correspondence: ; Tel.: +39-049-827-6300
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31
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Baloh RH. The Nerve to Give BACE Inhibitors a Second Chance? Neurotherapeutics 2020; 17:966-967. [PMID: 32514890 PMCID: PMC7609629 DOI: 10.1007/s13311-020-00876-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Robert H Baloh
- Department of Neurology, Center for Neural Science and Medicine, Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA, 90048, USA.
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32
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Suzuki N, Akiyama T, Warita H, Aoki M. Omics Approach to Axonal Dysfunction of Motor Neurons in Amyotrophic Lateral Sclerosis (ALS). Front Neurosci 2020; 14:194. [PMID: 32269505 PMCID: PMC7109447 DOI: 10.3389/fnins.2020.00194] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 02/24/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an intractable adult-onset neurodegenerative disease that leads to the loss of upper and lower motor neurons (MNs). The long axons of MNs become damaged during the early stages of ALS. Genetic and pathological analyses of ALS patients have revealed dysfunction in the MN axon homeostasis. However, the molecular pathomechanism for the degeneration of axons in ALS has not been fully elucidated. This review provides an overview of the proposed axonal pathomechanisms in ALS, including those involving the neuronal cytoskeleton, cargo transport within axons, axonal energy supply, clearance of junk protein, neuromuscular junctions (NMJs), and aberrant axonal branching. To improve understanding of the global changes in axons, the review summarizes omics analyses of the axonal compartments of neurons in vitro and in vivo, including a motor nerve organoid approach that utilizes microfluidic devices developed by this research group. The review also discusses the relevance of intra-axonal transcription factors frequently identified in these omics analyses. Local axonal translation and the relationship among these pathomechanisms should be pursued further. The development of novel strategies to analyze axon fractions provides a new approach to establishing a detailed understanding of resilience of long MN and MN pathology in ALS.
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Affiliation(s)
- Naoki Suzuki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.,Department of Neurology, Shodo-kai Southern Tohoku General Hospital, Miyagi, Japan
| | - Tetsuya Akiyama
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Hitoshi Warita
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
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33
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Larrea D, Pera M, Gonnelli A, Quintana-Cabrera R, Akman HO, Guardia-Laguarta C, Velasco KR, Area-Gomez E, Dal Bello F, De Stefani D, Horvath R, Shy ME, Schon EA, Giacomello M. MFN2 mutations in Charcot-Marie-Tooth disease alter mitochondria-associated ER membrane function but do not impair bioenergetics. Hum Mol Genet 2020; 28:1782-1800. [PMID: 30649465 PMCID: PMC6522073 DOI: 10.1093/hmg/ddz008] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/27/2018] [Accepted: 12/31/2018] [Indexed: 12/23/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT) type 2A is a form of peripheral neuropathy, due almost exclusively to dominant mutations in the nuclear gene encoding the mitochondrial protein mitofusin-2 (MFN2). However, there is no understanding of the relationship of clinical phenotype to genotype. MFN2 has two functions: it promotes inter-mitochondrial fusion and mediates endoplasmic reticulum (ER)-mitochondrial tethering at mitochondria-associated ER membranes (MAM). MAM regulates a number of key cellular functions, including lipid and calcium homeostasis, and mitochondrial behavior. To date, no studies have been performed to address whether mutations in MFN2 in CMT2A patient cells affect MAM function, which might provide insight into pathogenesis. Using fibroblasts from three CMT2AMFN2 patients with different mutations in MFN2, we found that some, but not all, examined aspects of ER-mitochondrial connectivity and of MAM function were indeed altered, and correlated with disease severity. Notably, however, respiratory chain function in those cells was unimpaired. Our results suggest that CMT2AMFN2 is a MAM-related disorder but is not a respiratory chain-deficiency disease. The alterations in MAM function described here could also provide insight into the pathogenesis of other forms of CMT.
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Affiliation(s)
- Delfina Larrea
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Marta Pera
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | | | | | - H Orhan Akman
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | | | - Kevin R Velasco
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | - Estela Area-Gomez
- Department of Neurology, Columbia University Medical Center, New York, NY, USA
| | | | | | - Rita Horvath
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Michael E Shy
- Department of Neurology, University of Iowa, Iowa City, IA, USA
| | - Eric A Schon
- Department of Neurology, Columbia University Medical Center, New York, NY, USA.,Department of Genetics and Development, Columbia University Medical Center, New York, NY, USA
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34
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Öztürk Z, O’Kane CJ, Pérez-Moreno JJ. Axonal Endoplasmic Reticulum Dynamics and Its Roles in Neurodegeneration. Front Neurosci 2020; 14:48. [PMID: 32116502 PMCID: PMC7025499 DOI: 10.3389/fnins.2020.00048] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
The physical continuity of axons over long cellular distances poses challenges for their maintenance. One organelle that faces this challenge is endoplasmic reticulum (ER); unlike other intracellular organelles, this forms a physically continuous network throughout the cell, with a single membrane and a single lumen. In axons, ER is mainly smooth, forming a tubular network with occasional sheets or cisternae and low amounts of rough ER. It has many potential roles: lipid biosynthesis, glucose homeostasis, a Ca2+ store, protein export, and contacting and regulating other organelles. This tubular network structure is determined by ER-shaping proteins, mutations in some of which are causative for neurodegenerative disorders such as hereditary spastic paraplegia (HSP). While axonal ER shares many features with the tubular ER network in other contexts, these features must be adapted to the long and narrow dimensions of axons. ER appears to be physically continuous throughout axons, over distances that are enormous on a subcellular scale. It is therefore a potential channel for long-distance or regional communication within neurons, independent of action potentials or physical transport of cargos, but involving its physiological roles such as Ca2+ or organelle homeostasis. Despite its apparent stability, axonal ER is highly dynamic, showing features like anterograde and retrograde transport, potentially reflecting continuous fusion and breakage of the network. Here we discuss the transport processes that must contribute to this dynamic behavior of ER. We also discuss the model that these processes underpin a homeostatic process that ensures both enough ER to maintain continuity of the network and repair breaks in it, but not too much ER that might disrupt local cellular physiology. Finally, we discuss how failure of ER organization in axons could lead to axon degenerative diseases, and how a requirement for ER continuity could make distal axons most susceptible to degeneration in conditions that disrupt ER continuity.
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Affiliation(s)
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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35
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Neuronal Mitochondria Modulation of LPS-Induced Neuroinflammation. J Neurosci 2020; 40:1756-1765. [PMID: 31937559 DOI: 10.1523/jneurosci.2324-19.2020] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/04/2019] [Accepted: 01/01/2020] [Indexed: 12/14/2022] Open
Abstract
Neuronal mitochondria dysfunction and neuroinflammation are two prominent pathological features increasingly realized as important pathogenic mechanisms for neurodegenerative diseases. However, little attempt has been taken to investigate the likely interactions between them. Mitofusin2 (Mfn2) is a mitochondrial outer membrane protein regulating mitochondrial fusion, a dynamic process essential for mitochondrial function. To explore the significance of neuronal mitochondria in the regulation of neuroinflammation, male and female transgenic mice with forced overexpression of Mfn2 specifically in neurons were intraperitoneally injected with lipopolysaccharide (LPS), a widely used approach to model neurodegeneration-associated neuroinflammation. Remarkably, LPS-induced lethality was almost completely abrogated in neuronal Mfn2 overexpression mice. Compared with nontransgenic wild-type mice, mice with neuronal Mfn2 overexpression also exhibited alleviated bodyweight loss, behavioral sickness, and myocardial dysfunction. LPS-induced release of IL-1β but not TNF-α was further found greatly inhibited in the CNS of mice with neuronal Mfn2 overexpression, whereas peripheral inflammatory responses in the blood, heart, lung, and spleen remained unchanged. At the cellular and molecular levels, neuronal Mfn2 suppressed the activation of microglia, prevented LPS-induced mitochondrial fragmentation in neurons, and importantly, upregulated the expression of CX3CL1, a unique chemokine constitutively produced by neurons to suppress microglial activation. Together, these results reveal an unrecognized possible role of neuronal mitochondria in the regulation of microglial activation, and propose neuronal Mfn2 as a likely mechanistic linker between neuronal mitochondria dysfunction and neuroinflammation in neurodegeneration.SIGNIFICANCE STATEMENT Our study suggests that Mfn2 in neurons contributes to the regulation of neuroinflammation. Based on the remarkable suppression of LPS-induced neuroinflammation and neurodegeneration-associated mitochondrial dysfunction and dynamic abnormalities by neuronal Mfn2, this study centered on Mfn2-mediated neuroinflammation reveals novel molecular mechanisms that are involved in both mitochondrial dysfunction and neuroinflammation in neurodegenerative diseases. The pharmacological targeting of Mfn2 may present a novel treatment for neuroinflammation-associated diseases.
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36
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Gao J, Wang L, Yan T, Perry G, Wang X. TDP-43 proteinopathy and mitochondrial abnormalities in neurodegeneration. Mol Cell Neurosci 2019; 100:103396. [PMID: 31445085 DOI: 10.1016/j.mcn.2019.103396] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/03/2019] [Accepted: 08/17/2019] [Indexed: 12/12/2022] Open
Abstract
Genetic mutations in TAR DNA-binding protein 43 (TDP-43) cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Importantly, TDP-43 proteinopathy, characterized by aberrant phosphorylation, ubiquitination, cleavage or nuclear depletion of TDP-43 in neurons and glial cells, is a common prominent pathological feature of various major neurodegenerative diseases including ALS, FTD, and Alzheimer's disease (AD). Although the pathomechanisms underlying TDP-43 proteinopathy remain elusive, pathologically relevant TDP-43 has been repeatedly shown to be present in either the inside or outside of mitochondria, and functionally involved in the regulation of mitochondrial morphology, trafficking, and function, suggesting mitochondria as likely targets of TDP-43 proteinopathy. In this review, we first describe the current knowledge of the association of TDP-43 with mitochondria. We then review in detail multiple mitochondrial pathways perturbed by pathological TDP-43, including mitochondrial fission and fusion dynamics, mitochondrial trafficking, bioenergetics, and mitochondrial quality control. Lastly, we briefly discuss how the study of TDP-43 proteinopathy and mitochondrial abnormalities may provide new avenues for neurodegeneration therapeutics.
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Affiliation(s)
- Ju Gao
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Luwen Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - Tingxiang Yan
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, TX, USA
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA.
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37
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Goldstein O, Kedmi M, Gana-Weisz M, Twito S, Nefussy B, Vainer B, Fainmesser Y, Abraham A, Nayshool O, Orr-Urtreger A, Drory VE. Rare homozygosity in amyotrophic lateral sclerosis suggests the contribution of recessive variants to disease genetics. J Neurol Sci 2019; 402:62-68. [DOI: 10.1016/j.jns.2019.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 05/02/2019] [Accepted: 05/07/2019] [Indexed: 02/06/2023]
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38
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Gentile F, Scarlino S, Falzone YM, Lunetta C, Tremolizzo L, Quattrini A, Riva N. The Peripheral Nervous System in Amyotrophic Lateral Sclerosis: Opportunities for Translational Research. Front Neurosci 2019; 13:601. [PMID: 31293369 PMCID: PMC6603245 DOI: 10.3389/fnins.2019.00601] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/27/2019] [Indexed: 12/11/2022] Open
Abstract
Although amyotrophic lateral sclerosis (ALS) has been considered as a disorder of the motor neuron (MN) cell body, recent evidences show the non-cell-autonomous pathogenic nature of the disease. Axonal degeneration, loss of peripheral axons and destruction of nerve terminals are early events in the disease pathogenic cascade, anticipating MN degeneration, and the onset of clinical symptoms. Therefore, although ALS and peripheral axonal neuropathies should be differentiated in clinical practice, they also share damage to common molecular pathways, including axonal transport, RNA metabolism and proteostasis. Thus, an extensive evaluation of the molecular events occurring in the peripheral nervous system (PNS) could be fundamental to understand the pathogenic mechanisms of ALS, favoring the discovery of potential disease biomarkers, and new therapeutic targets.
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Affiliation(s)
- Francesco Gentile
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
| | - Stefania Scarlino
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
| | - Yuri Matteo Falzone
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
- Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
| | | | - Lucio Tremolizzo
- Neurology Unit, ALS Clinic, San Gerardo Hospital, University of Milano-Bicocca, Monza, Italy
| | - Angelo Quattrini
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
| | - Nilo Riva
- Experimental Neuropathology Unit, Division of Neuroscience, Institute of Experimental Neurology – San Raffaele Scientific Institute, Milan, Italy
- Department of Neurology, San Raffaele Scientific Institute, Milan, Italy
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39
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Zhou Y, Carmona S, Muhammad AKMG, Bell S, Landeros J, Vazquez M, Ho R, Franco A, Lu B, Dorn GW, Wang S, Lutz CM, Baloh RH. Restoring mitofusin balance prevents axonal degeneration in a Charcot-Marie-Tooth type 2A model. J Clin Invest 2019; 129:1756-1771. [PMID: 30882371 DOI: 10.1172/jci124194] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 01/29/2019] [Indexed: 01/08/2023] Open
Abstract
Mitofusin-2 (MFN2) is a mitochondrial outer-membrane protein that plays a pivotal role in mitochondrial dynamics in most tissues, yet mutations in MFN2, which cause Charcot-Marie-Tooth disease type 2A (CMT2A), primarily affect the nervous system. We generated a transgenic mouse model of CMT2A that developed severe early onset vision loss and neurological deficits, axonal degeneration without cell body loss, and cytoplasmic and axonal accumulations of fragmented mitochondria. While mitochondrial aggregates were labeled for mitophagy, mutant MFN2 did not inhibit Parkin-mediated degradation, but instead had a dominant negative effect on mitochondrial fusion only when MFN1 was at low levels, as occurs in neurons. Finally, using a transgenic approach, we found that augmenting the level of MFN1 in the nervous system in vivo rescued all phenotypes in mutant MFN2R94Q-expressing mice. These data demonstrate that the MFN1/MFN2 ratio is a key determinant of tissue specificity in CMT2A and indicate that augmentation of MFN1 in the nervous system is a viable therapeutic strategy for the disease.
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Affiliation(s)
- Yueqin Zhou
- Center for Neural Science and Medicine, and.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Sharon Carmona
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - A K M G Muhammad
- Center for Neural Science and Medicine, and.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Shaughn Bell
- Center for Neural Science and Medicine, and.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Jesse Landeros
- Center for Neural Science and Medicine, and.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Michael Vazquez
- Center for Neural Science and Medicine, and.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Ritchie Ho
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Antonietta Franco
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Bin Lu
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Gerald W Dorn
- Center for Pharmacogenomics, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Shaomei Wang
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | - Robert H Baloh
- Center for Neural Science and Medicine, and.,Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA.,Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, California, USA
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40
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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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41
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Abstract
How neuromuscular junctions (NMJs) are lost in disease and aging is unclear. Recently in Cell Metabolism, Wang et al. (2018) discovered that endoplasmic reticulum-mitochondria tethering by Mitofusin 2 is required to organize a cleft between these two organelles, which, like a lorry, traffics down the axon to distribute calpastatin to terminals where it blocks NMJ degradation.
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