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Xie X, Huang C. Role of the gut-muscle axis in mitochondrial function of ageing muscle under different exercise modes. Ageing Res Rev 2024; 98:102316. [PMID: 38703951 DOI: 10.1016/j.arr.2024.102316] [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: 12/21/2023] [Revised: 03/29/2024] [Accepted: 04/26/2024] [Indexed: 05/06/2024]
Abstract
The fundamental role of the gut microbiota through the gut-muscle axis in skeletal muscle ageing is increasingly recognised. Metabolites derived from the intestinal microbiota are essential in maintaining skeletal muscle function and metabolism. The energy produced by mitochondria and moderate levels of reactive oxygen species can contribute to this process. Metabolites can effectively target the mitochondria, slowing the progression of muscle ageing and potentially representing a marker of ageing-related skeletal muscle loss. Moreover, mitochondria can contribute to the immune response, gut microbiota biodiversity, and maintenance of the intestinal barrier function. However, the causal relationship between mitochondrial function and gut microbiota crosstalk remains poorly understood. In addition to elucidating the regulatory pathways of the gut-muscle axis during the ageing process, we focused on the potential role of the "exercise-gut-muscle axis", which represents a pathway under stimulation from different exercise modes to induce mitochondrial adaptations, skeletal muscle metabolism and maintain intestinal barrier function and biodiversity stability. Meanwhile, different exercise modes can induce mitochondrial adaptations and skeletal muscle metabolism and maintain intestinal barrier function and biodiversity. Resistance exercise may promote mitochondrial adaptation, increase the cross-sectional area of skeletal muscle and muscle hypertrophy, and promote muscle fibre and motor unit recruitment. Whereas endurance exercise promotes mitochondrial biogenesis, aerobic capacity, and energy utilisation, activating oxidative metabolism-related pathways to improve skeletal muscle metabolism and function. This review describes the effects of different exercise modes through the gut-muscle axis and how they act through mitochondria in ageing to define the current state of the field and issues requiring resolution.
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Affiliation(s)
- Xiaoting Xie
- Department of Sports Science, Zhejiang University, Hangzhou, China; Laboratory for Digital Sports and Health, College of Education, Zhejiang University, Hangzhou, China
| | - Cong Huang
- Department of Sports Science, Zhejiang University, Hangzhou, China; Laboratory for Digital Sports and Health, College of Education, Zhejiang University, Hangzhou, China; Department of Medicine and Science in Sports and Exercise, Tohoku University Graduate School of Medicine, Sendai, Japan.
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2
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Koga D, Kusumi S, Yagi H, Kato K. Three-dimensional analysis of the intracellular architecture by scanning electron microscopy. Microscopy (Oxf) 2024; 73:215-225. [PMID: 37930813 DOI: 10.1093/jmicro/dfad050] [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: 06/19/2023] [Revised: 10/05/2023] [Accepted: 10/27/2023] [Indexed: 11/08/2023] Open
Abstract
The two-dimensional observation of ultrathin sections from resin-embedded specimens provides an insufficient understanding of the three-dimensional (3D) morphological information of membranous organelles. The osmium maceration method, developed by Professor Tanaka's group >40 years ago, is the only technique that allows direct observation of the 3D ultrastructure of membrane systems using scanning electron microscopy (SEM), without the need for any reconstruction process. With this method, the soluble cytoplasmic proteins are removed from the freeze-cracked surface of cells while preserving the integrity of membranous organelles, achieved by immersing tissues in a diluted osmium solution for several days. By employing the maceration method, researchers using SEM have revealed the 3D ultrastructure of organelles such as the Golgi apparatus, mitochondria and endoplasmic reticulum in various cell types. Recently, we have developed new SEM techniques based on the maceration method to explore further possibilities of this method. These include: (i) a rapid osmium maceration method that reduces the reaction duration of the procedure, (ii) a combination method that combines agarose embedding with osmium maceration to elucidate the 3D ultrastructure of organelles in free and cultured cells and (iii) a correlative immunofluorescence and SEM technique that combines cryosectioning with the osmium maceration method, enabling the correlation of the immunocytochemical localization of molecules with the 3D ultrastructure of organelles. In this paper, we review the novel osmium maceration methods described earlier and discuss their potential and future directions in the field of biology and biomedical research.
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Affiliation(s)
- Daisuke Koga
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, 2-1-1-1 Midorigaoka-higashi, Asahikawa 078-8510, Japan
| | - Satoshi Kusumi
- Division of Morphological Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1, Sakuragaoka, Kagoshima 890-8544, Japan
| | - Hirokazu Yagi
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori 3-1, Mizuho-ku, Nagoya 467-8603, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki 444-8787, Japan
| | - Koichi Kato
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori 3-1, Mizuho-ku, Nagoya 467-8603, Japan
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki 444-8787, Japan
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3
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Liu M, You Y, Zhu H, Chen Y, Hu Z, Duan J. N-Acetylcysteine Alleviates Impaired Muscular Function Resulting from Sphingosine Phosphate Lyase Functional Deficiency-Induced Sphingoid Base and Ceramide Accumulation in Caenorhabditis elegans. Nutrients 2024; 16:1623. [PMID: 38892556 PMCID: PMC11174433 DOI: 10.3390/nu16111623] [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: 04/16/2024] [Revised: 05/18/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024] Open
Abstract
Sphingosine-1-phosphate lyase (SPL) resides at the endpoint of the sphingolipid metabolic pathway, catalyzing the irreversible breakdown of sphingosine-1-phosphate. Depletion of SPL precipitates compromised muscle morphology and function; nevertheless, the precise mechanistic underpinnings remain elusive. Here, we elucidate a model of SPL functional deficiency in Caenorhabditis elegans using spl-1 RNA interference. Within these SPL-deficient nematodes, we observed diminished motility and perturbed muscle fiber organization, correlated with the accumulation of sphingoid bases, their phosphorylated forms, and ceramides (collectively referred to as the "sphingolipid rheostat"). The disturbance in mitochondrial morphology was also notable, as SPL functional loss resulted in heightened levels of reactive oxygen species. Remarkably, the administration of the antioxidant N-acetylcysteine (NAC) ameliorates locomotor impairment and rectifies muscle fiber disarray, underscoring its therapeutic promise for ceramide-accumulation-related muscle disorders. Our findings emphasize the pivotal role of SPL in preserving muscle integrity and advocate for exploring antioxidant interventions, such as NAC supplementation, as prospective therapeutic strategies for addressing muscle function decline associated with sphingolipid/ceramide metabolism disruption.
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Affiliation(s)
| | | | | | | | - Zhenying Hu
- Jiangxi Province Key Laboratory of Aging and Disease, Human Aging Research Institute (HARI), School of Life Science, Nanchang University, Nanchang 330031, China
| | - Jingjing Duan
- Jiangxi Province Key Laboratory of Aging and Disease, Human Aging Research Institute (HARI), School of Life Science, Nanchang University, Nanchang 330031, China
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4
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Nieblas B, Pérez-Treviño P, García N. Role of mitochondria-associated endoplasmic reticulum membranes in insulin sensitivity, energy metabolism, and contraction of skeletal muscle. Front Mol Biosci 2022; 9:959844. [PMID: 36275635 PMCID: PMC9585326 DOI: 10.3389/fmolb.2022.959844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/04/2022] [Indexed: 11/29/2022] Open
Abstract
Skeletal muscle has a critical role in the regulation of the energy balance of the organism, particularly as the principal tissue responsible for insulin-stimulated glucose disposal and as the major site of peripheral insulin resistance (IR), which has been related to accumulation of lipid intermediates, reduced oxidative capacity of mitochondria and endoplasmic reticulum (ER) stress. These organelles form contact sites, known as mitochondria-associated ER membranes (MAMs). This interconnection seems to be involved in various cellular processes, including Ca2+ transport and energy metabolism; therefore, MAMs could play an important role in maintaining cellular homeostasis. Evidence suggests that alterations in MAMs may contribute to IR. However, the evidence does not refer to a specific subcellular location, which is of interest due to the fact that skeletal muscle is constituted by oxidative and glycolytic fibers as well as different mitochondrial populations that appear to respond differently to stimuli and pathological conditions. In this review, we show the available evidence of possible differential responses in the formation of MAMs in skeletal muscle as well as its role in insulin signaling and the beneficial effect it could have in the regulation of energetic metabolism and muscular contraction.
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Affiliation(s)
- Bianca Nieblas
- Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Nuevo León, México
- Experimental Medicine and Advanced Therapies, The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Nuevo León, México
| | - Perla Pérez-Treviño
- Experimental Medicine and Advanced Therapies, The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Nuevo León, México
| | - Noemí García
- Escuela de Medicina y Ciencias de la Salud, Tecnologico de Monterrey, Monterrey, Nuevo León, México
- Experimental Medicine and Advanced Therapies, The Institute for Obesity Research, Tecnologico de Monterrey, Monterrey, Nuevo León, México
- *Correspondence: Noemí García,
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5
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A 3D analysis revealed complexe mitochondria morphologies in porcine cumulus cells. Sci Rep 2022; 12:15403. [PMID: 36100690 PMCID: PMC9470746 DOI: 10.1038/s41598-022-19723-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 09/02/2022] [Indexed: 11/09/2022] Open
Abstract
In the ovarian follicle, a bilateral cell-to-cell communication exists between the female germ cell and the cumulus cells which surround the oocyte. This communication allows the transit of small size molecules known to impact oocyte developmental competence. Pyruvate derivatives produced by mitochondria, are one of these transferred molecules. Interestingly, mitochondria may adopt a variety of morphologies to regulate their functions. In this study, we described mitochondrial morphologies in porcine cumulus cells. Active mitochondria were stained with TMRM (Tetramethylrhodamine, Methyl Ester, Perchlorate) and observed with 2D confocal microscopy showing mitochondria of different morphologies such as short, intermediate, long, and very long. The number of mitochondria of each phenotype was quantified in cells and the results showed that most cells contained elongated mitochondria. Scanning electron microscopy (SEM) analysis confirmed at nanoscale resolution the different mitochondrial morphologies including round, short, intermediate, and long. Interestingly, 3D visualisation by focused ion-beam scanning electron microscopy (FIB-SEM) revealed different complex mitochondrial morphologies including connected clusters of different sizes, branched mitochondria, as well as individual mitochondria. Since mitochondrial dynamics is a key regulator of function, the description of the mitochondrial network organisation will allow to further study mitochondrial dynamics in cumulus cells in response to various conditions such as in vitro maturation.
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Bolaños P, Calderón JC. Excitation-contraction coupling in mammalian skeletal muscle: Blending old and last-decade research. Front Physiol 2022; 13:989796. [PMID: 36117698 PMCID: PMC9478590 DOI: 10.3389/fphys.2022.989796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/08/2022] [Indexed: 11/13/2022] Open
Abstract
The excitation–contraction coupling (ECC) in skeletal muscle refers to the Ca2+-mediated link between the membrane excitation and the mechanical contraction. The initiation and propagation of an action potential through the membranous system of the sarcolemma and the tubular network lead to the activation of the Ca2+-release units (CRU): tightly coupled dihydropyridine and ryanodine (RyR) receptors. The RyR gating allows a rapid, massive, and highly regulated release of Ca2+ from the sarcoplasmic reticulum (SR). The release from triadic places generates a sarcomeric gradient of Ca2+ concentrations ([Ca2+]) depending on the distance of a subcellular region from the CRU. Upon release, the diffusing Ca2+ has multiple fates: binds to troponin C thus activating the contractile machinery, binds to classical sarcoplasmic Ca2+ buffers such as parvalbumin, adenosine triphosphate and, experimentally, fluorescent dyes, enters the mitochondria and the SR, or is recycled through the Na+/Ca2+ exchanger and store-operated Ca2+ entry (SOCE) mechanisms. To commemorate the 7th decade after being coined, we comprehensively and critically reviewed “old”, historical landmarks and well-established concepts, and blended them with recent advances to have a complete, quantitative-focused landscape of the ECC. We discuss the: 1) elucidation of the CRU structures at near-atomic resolution and its implications for functional coupling; 2) reliable quantification of peak sarcoplasmic [Ca2+] using fast, low affinity Ca2+ dyes and the relative contributions of the Ca2+-binding mechanisms to the whole concert of Ca2+ fluxes inside the fibre; 3) articulation of this novel quantitative information with the unveiled structural details of the molecular machinery involved in mitochondrial Ca2+ handing to understand how and how much Ca2+ enters the mitochondria; 4) presence of the SOCE machinery and its different modes of activation, which awaits understanding of its magnitude and relevance in situ; 5) pharmacology of the ECC, and 6) emerging topics such as the use and potential applications of super-resolution and induced pluripotent stem cells (iPSC) in ECC. Blending the old with the new works better!
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Affiliation(s)
- Pura Bolaños
- Laboratory of Cellular Physiology, Centre of Biophysics and Biochemistry, Venezuelan Institute for Scientific Research (IVIC), Caracas, Venezuela
| | - Juan C. Calderón
- Physiology and Biochemistry Research Group-PHYSIS, Faculty of Medicine, University of Antioquia, Medellín, Colombia
- *Correspondence: Juan C. Calderón,
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7
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Chen M, Wang Y, Deng S, Lian Z, Yu K. Skeletal muscle oxidative stress and inflammation in aging: Focus on antioxidant and anti-inflammatory therapy. Front Cell Dev Biol 2022; 10:964130. [PMID: 36111339 PMCID: PMC9470179 DOI: 10.3389/fcell.2022.964130] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/10/2022] [Indexed: 12/06/2022] Open
Abstract
With aging, the progressive loss of skeletal muscle will have negative effect on multiple physiological parameters, such as exercise, respiration, thermoregulation, and metabolic homeostasis. Accumulating evidence reveals that oxidative stress and inflammation are the main pathological characteristics of skeletal muscle during aging. Here, we focus on aging-related sarcopenia, summarize the relationship between aging and sarcopenia, and elaborate on aging-mediated oxidative stress and oxidative damage in skeletal muscle and its critical role in the occurrence and development of sarcopenia. In addition, we discuss the production of excessive reactive oxygen species in aging skeletal muscle, which reduces the ability of skeletal muscle satellite cells to participate in muscle regeneration, and analyze the potential molecular mechanism of ROS-mediated mitochondrial dysfunction in aging skeletal muscle. Furthermore, we have also paid extensive attention to the possibility and potential regulatory pathways of skeletal muscle aging and oxidative stress mediate inflammation. Finally, in response to the abnormal activity of oxidative stress and inflammation during aging, we summarize several potential antioxidant and anti-inflammatory strategies for the treatment of sarcopenia, which may provide beneficial help for improving sarcopenia during aging.
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Affiliation(s)
- Mingming Chen
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yiyi Wang
- Zhejiang A&F University, Zhejiang Provincial Key Laboratory of Characteristic Traditional Chinese Medicine Resources Protection and Innovative Utilization, Lin’an, China
| | - Shoulong Deng
- NHC Key Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Zhengxing Lian
- College of Animal Science and Technology, China Agricultural University, Beijing, China
- *Correspondence: Zhengxing Lian, ; Kun Yu,
| | - Kun Yu
- College of Animal Science and Technology, China Agricultural University, Beijing, China
- *Correspondence: Zhengxing Lian, ; Kun Yu,
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8
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Chen MM, Li Y, Deng SL, Zhao Y, Lian ZX, Yu K. Mitochondrial Function and Reactive Oxygen/Nitrogen Species in Skeletal Muscle. Front Cell Dev Biol 2022; 10:826981. [PMID: 35265618 PMCID: PMC8898899 DOI: 10.3389/fcell.2022.826981] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/26/2022] [Indexed: 12/06/2022] Open
Abstract
Skeletal muscle fibers contain a large number of mitochondria, which produce ATP through oxidative phosphorylation (OXPHOS) and provide energy for muscle contraction. In this process, mitochondria also produce several types of "reactive species" as side product, such as reactive oxygen species and reactive nitrogen species which have attracted interest. Mitochondria have been proven to have an essential role in the production of skeletal muscle reactive oxygen/nitrogen species (RONS). Traditionally, the elevation in RONS production is related to oxidative stress, leading to impaired skeletal muscle contractility and muscle atrophy. However, recent studies have shown that the optimal RONS level under the action of antioxidants is a critical physiological signal in skeletal muscle. Here, we will review the origin and physiological functions of RONS, mitochondrial structure and function, mitochondrial dynamics, and the coupling between RONS and mitochondrial oxidative stress. The crosstalk mechanism between mitochondrial function and RONS in skeletal muscle and its regulation of muscle stem cell fate and myogenesis will also be discussed. In all, this review aims to describe a comprehensive and systematic network for the interaction between skeletal muscle mitochondrial function and RONS.
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Affiliation(s)
- Ming-Ming Chen
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yan Li
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Shou-Long Deng
- NHC Key Laboratory of Human Disease Comparative Medicine, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences and Comparative Medicine Center, Peking Union Medical College, Beijing, China
| | - Yue Zhao
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Zheng-Xing Lian
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Kun Yu
- College of Animal Science and Technology, China Agricultural University, Beijing, China
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9
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H2O2/Ca2+/Zn2+ Complex Can Be Considered a “Collaborative Sensor” of the Mitochondrial Capacity? Antioxidants (Basel) 2022; 11:antiox11020342. [PMID: 35204224 PMCID: PMC8868167 DOI: 10.3390/antiox11020342] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 02/04/2023] Open
Abstract
In order to maintain a state of well-being, the cell needs a functional control center that allows it to respond to changes in the internal and surrounding environments and, at the same time, carry out the necessary metabolic functions. In this review, we identify the mitochondrion as such an “agora”, in which three main messengers are able to collaborate and activate adaptive response mechanisms. Such response generators, which we have identified as H2O2, Ca2+, and Zn2+, are capable of “reading” the environment and talking to each other in cooperation with the mitochondrion. In this manner, these messengers exchange information and generate a holistic response of the whole cell, dependent on its functional state. In this review, to corroborate this claim, we analyzed the role these actors, which in the review we call “sensors”, play in the regulation of skeletal muscle contractile capacities chosen as a model of crosstalk between Ca2+, Zn2+, and H2O2.
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10
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Oxygen flux from capillary to mitochondria: integration of contemporary discoveries. Eur J Appl Physiol 2022; 122:7-28. [PMID: 34940908 PMCID: PMC8890444 DOI: 10.1007/s00421-021-04854-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 11/18/2021] [Indexed: 01/03/2023]
Abstract
Resting humans transport ~ 100 quintillion (1018) oxygen (O2) molecules every second to tissues for consumption. The final, short distance (< 50 µm) from capillary to the most distant mitochondria, in skeletal muscle where exercising O2 demands may increase 100-fold, challenges our understanding of O2 transport. To power cellular energetics O2 reaches its muscle mitochondrial target by dissociating from hemoglobin, crossing the red cell membrane, plasma, endothelial surface layer, endothelial cell, interstitial space, myocyte sarcolemma and a variable expanse of cytoplasm before traversing the mitochondrial outer/inner membranes and reacting with reduced cytochrome c and protons. This past century our understanding of O2's passage across the body's final O2 frontier has been completely revised. This review considers the latest structural and functional data, challenging the following entrenched notions: (1) That O2 moves freely across blood cell membranes. (2) The Krogh-Erlang model whereby O2 pressure decreases systematically from capillary to mitochondria. (3) Whether intramyocyte diffusion distances matter. (4) That mitochondria are separate organelles rather than coordinated and highly plastic syncytia. (5) The roles of free versus myoglobin-facilitated O2 diffusion. (6) That myocytes develop anoxic loci. These questions, and the intriguing notions that (1) cellular membranes, including interconnected mitochondrial membranes, act as low resistance conduits for O2, lipids and H+-electrochemical transport and (2) that myoglobin oxy/deoxygenation state controls mitochondrial oxidative function via nitric oxide, challenge established tenets of muscle metabolic control. These elements redefine muscle O2 transport models essential for the development of effective therapeutic countermeasures to pathological decrements in O2 supply and physical performance.
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11
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Koga D, Kusumi S, Shibata M, Watanabe T. Applications of Scanning Electron Microscopy Using Secondary and Backscattered Electron Signals in Neural Structure. Front Neuroanat 2021; 15:759804. [PMID: 34955763 PMCID: PMC8693767 DOI: 10.3389/fnana.2021.759804] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 11/12/2021] [Indexed: 11/18/2022] Open
Abstract
Scanning electron microscopy (SEM) has contributed to elucidating the ultrastructure of bio-specimens in three dimensions. SEM imagery detects several kinds of signals, of which secondary electrons (SEs) and backscattered electrons (BSEs) are the main electrons used in biological and biomedical research. SE and BSE signals provide a three-dimensional (3D) surface topography and information on the composition of specimens, respectively. Among the various sample preparation techniques for SE-mode SEM, the osmium maceration method is the only approach for examining the subcellular structure that does not require any reconstruction processes. The 3D ultrastructure of organelles, such as the Golgi apparatus, mitochondria, and endoplasmic reticulum has been uncovered using high-resolution SEM of osmium-macerated tissues. Recent instrumental advances in scanning electron microscopes have broadened the applications of SEM for examining bio-specimens and enabled imaging of resin-embedded tissue blocks and sections using BSE-mode SEM under low-accelerating voltages; such techniques are fundamental to the 3D-SEM methods that are now known as focused ion-beam SEM, serial block-face SEM, and array tomography (i.e., serial section SEM). This technical breakthrough has allowed us to establish an innovative BSE imaging technique called section-face imaging to acquire ultrathin information from resin-embedded tissue sections. In contrast, serial section SEM is a modern 3D imaging technique for creating 3D surface rendering models of cells and organelles from tomographic BSE images of consecutive ultrathin sections embedded in resin. In this article, we introduce our related SEM techniques that use SE and BSE signals, such as the osmium maceration method, semithin section SEM (section-face imaging of resin-embedded semithin sections), section-face imaging for correlative light and SEM, and serial section SEM, to summarize their applications to neural structure and discuss the future possibilities and directions for these methods.
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Affiliation(s)
- Daisuke Koga
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
| | - Satoshi Kusumi
- Department of Morphological Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Masahiro Shibata
- Department of Morphological Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tsuyoshi Watanabe
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
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12
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Recurrent erosion of COA1/MITRAC15 exemplifies conditional gene dispensability in oxidative phosphorylation. Sci Rep 2021; 11:24437. [PMID: 34952909 PMCID: PMC8709867 DOI: 10.1038/s41598-021-04077-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 12/15/2021] [Indexed: 11/08/2022] Open
Abstract
Skeletal muscle fibers rely upon either oxidative phosphorylation or the glycolytic pathway with much less reliance on oxidative phosphorylation to achieve muscular contractions that power mechanical movements. Species with energy-intensive adaptive traits that require sudden bursts of energy have a greater dependency on glycolytic fibers. Glycolytic fibers have decreased reliance on OXPHOS and lower mitochondrial content compared to oxidative fibers. Hence, we hypothesized that gene loss might have occurred within the OXPHOS pathway in lineages that largely depend on glycolytic fibers. The protein encoded by the COA1/MITRAC15 gene with conserved orthologs found in budding yeast to humans promotes mitochondrial translation. We show that gene disrupting mutations have accumulated within the COA1 gene in the cheetah, several species of galliform birds, and rodents. The genomic region containing COA1 is a well-established evolutionary breakpoint region in mammals. Careful inspection of genome assemblies of closely related species of rodents and marsupials suggests two independent COA1 gene loss events co-occurring with chromosomal rearrangements. Besides recurrent gene loss events, we document changes in COA1 exon structure in primates and felids. The detailed evolutionary history presented in this study reveals the intricate link between skeletal muscle fiber composition and the occasional dispensability of the chaperone-like role of the COA1 gene.
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13
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Zhang X, Zhang L, Liu F, Hu S, Xu Q, Li F, Li H, Zhang G, Xu J. A unique red-emitting molecular rotor for high-fidelity visualizing and long-term tracking mitochondria. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2021; 260:119979. [PMID: 34052766 DOI: 10.1016/j.saa.2021.119979] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 05/07/2021] [Accepted: 05/17/2021] [Indexed: 06/12/2023]
Abstract
Visualizing and tracking mitochondrial changes is the key to understand the processes of diseases related to mitochondria, which is meaningful to physiology, pathology, and pharmacology. So, a great deal of mitochondrial probes was designed and synthesized according to the principle that probes with a positive charge can target mitochondria through mitochondrial membrane potential (MMP). However, these traditional mitochondrial probes are not able to visualize and track mitochondrial changes, because their targeting abilities depend on high MMP. Once MMP decreases, they will leak from mitochondria. Herein, we designed and synthesized a red-emitting molecule rotor (SQ, sensitive to viscosity) that could visualize mitochondria with high-fidelity. The rotor was able to firmly immobilize in mitochondrial inner membrane through the cooperation of MMP and the high viscosity property of mitochondrial membrane, and it could still stain mitochondria with long-term regardless of MMP changes. Hence, the probe is able to real-time image and distinguish four kinds of mitochondria with high-fidelity in muscle tissues. In addition, SQ can monitor mitochondrial autophagy in real time. These results demonstrate that SQ is a powerful tool for high-fidelity visualizing and long-term tracking mitochondria in vitro and in vivo.
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Affiliation(s)
- Xinxin Zhang
- School of Pharmacy, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China
| | - Long Zhang
- School of Chemistry, University of New South Wales, Sydney, New South Wales, Australia
| | - Fang Liu
- School of Pharmacy, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China
| | - Shuxin Hu
- School of Chemistry & Chemical Engineering, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China
| | - Quan Xu
- School of Pharmacy, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China
| | - Fei Li
- School of Pharmacy, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China
| | - Hui Li
- School of Pharmacy, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China
| | - Ge Zhang
- School of Chemistry & Chemical Engineering, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China.
| | - Jingkun Xu
- School of Chemistry & Chemical Engineering, Jiangxi Science & Technology Normal University, Nanchang 330013, PR China; College of Chemistry and Molecular Engineering, Qingdao University of Science & Technology, Qingdao 266042, PR China.
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14
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Abstract
The design of the energy metabolism system in striated muscle remains a major area of investigation. Here, we review our current understanding and emerging hypotheses regarding the metabolic support of muscle contraction. Maintenance of ATP free energy, so called energy homeostasis, via mitochondrial oxidative phosphorylation is critical to sustained contractile activity, and this major design criterion is the focus of this review. Cell volume invested in mitochondria reduces the space available for generating contractile force, and this spatial balance between mitochondria acontractile elements to meet the varying sustained power demands across muscle types is another important design criterion. This is accomplished with remarkably similar mass-specific mitochondrial protein composition across muscle types, implying that it is the organization of mitochondria within the muscle cell that is critical to supporting sustained muscle function. Beyond the production of ATP, ubiquitous distribution of ATPases throughout the muscle requires rapid distribution of potential energy across these large cells. Distribution of potential energy has long been thought to occur primarily through facilitated metabolite diffusion, but recent analysis has questioned the importance of this process under normal physiological conditions. Recent structural and functional studies have supported the hypothesis that the mitochondrial reticulum provides a rapid energy distribution system via the conduction of the mitochondrial membrane potential to maintain metabolic homeostasis during contractile activity. We extensively review this aspect of the energy metabolism design contrasting it with metabolite diffusion models and how mitochondrial structure can play a role in the delivery of energy in the striated muscle.
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Affiliation(s)
- Brian Glancy
- Muscle Energetics Laboratory, National Heart, Lung, and Blood Insititute and National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, Maryland
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Insititute, Bethesda, Maryland
| | - Robert S Balaban
- Muscle Energetics Laboratory, National Heart, Lung, and Blood Insititute and National Institute of Arthritis and Musculoskeletal and Skin Disease, Bethesda, Maryland
- Laboratory of Cardiac Energetics, National Heart, Lung, and Blood Insititute, Bethesda, Maryland
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15
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Leduc-Gaudet JP, Hussain SNA, Barreiro E, Gouspillou G. Mitochondrial Dynamics and Mitophagy in Skeletal Muscle Health and Aging. Int J Mol Sci 2021; 22:ijms22158179. [PMID: 34360946 PMCID: PMC8348122 DOI: 10.3390/ijms22158179] [Citation(s) in RCA: 93] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/23/2021] [Accepted: 07/27/2021] [Indexed: 01/18/2023] Open
Abstract
The maintenance of mitochondrial integrity is critical for muscle health. Mitochondria, indeed, play vital roles in a wide range of cellular processes, including energy supply, Ca2+ homeostasis, retrograde signaling, cell death, and many others. All mitochondria-containing cells, including skeletal muscle cells, dispose of several pathways to maintain mitochondrial health, including mitochondrial biogenesis, mitochondrial-derived vesicles, mitochondrial dynamics (fusion and fission process shaping mitochondrial morphology), and mitophagy—the process in charge of the removal of mitochondria though autophagy. The loss of skeletal muscle mass (atrophy) is a major health problem worldwide, especially in older people. Currently, there is no treatment to counteract the progressive decline in skeletal muscle mass and strength that occurs with aging, a process termed sarcopenia. There is increasing data, including our own, suggesting that accumulation of dysfunctional mitochondria contributes to the development of sarcopenia. Impairments in mitochondrial dynamics and mitophagy were recently proposed to contribute to sarcopenia. This review summarizes the current state of knowledge on the role played by mitochondrial dynamics and mitophagy in skeletal muscle health and in the development of sarcopenia. We also highlight recent studies showing that enhancing mitophagy in skeletal muscle is a promising therapeutic target to prevent or even treat skeletal muscle dysfunction in the elderly.
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Affiliation(s)
- Jean-Philippe Leduc-Gaudet
- Research Institute of the McGill University Health Centre, Department of Critical Care, Montréal, QC H4A 3J1, Canada; (S.N.A.H.); (G.G.)
- Meakins-Christie Laboratories, Department of Medicine, McGill University, Montréal, QC H4A 3J1, Canada
- Département des Sciences de l’activité Physique, Faculté des Sciences, UQAM, Montréal, QC H2X 1Y4, Canada
- Correspondence: ; Tel.: +1-514-476-6688
| | - Sabah N. A. Hussain
- Research Institute of the McGill University Health Centre, Department of Critical Care, Montréal, QC H4A 3J1, Canada; (S.N.A.H.); (G.G.)
- Meakins-Christie Laboratories, Department of Medicine, McGill University, Montréal, QC H4A 3J1, Canada
| | - Esther Barreiro
- Pulmonology Department-Muscle Wasting & Cachexia in Chronic Respiratory Diseases & Lung Cancer Research Group, IMIM-Hospital del Mar, Parc de Salut Mar, Biomedical Research Park (PRBB), C/Dr. Aiguader, 88, 08003 Barcelona, Spain;
- Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), Instituto de Salud Carlos III (ISCIII), 28029 Madrid, Spain
- Health and Experimental Sciences Department (CEXS), Pompeu Fabra University (UPF), Biomedical Research Park (PRBB), C/Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Gilles Gouspillou
- Research Institute of the McGill University Health Centre, Department of Critical Care, Montréal, QC H4A 3J1, Canada; (S.N.A.H.); (G.G.)
- Meakins-Christie Laboratories, Department of Medicine, McGill University, Montréal, QC H4A 3J1, Canada
- Département des Sciences de l’activité Physique, Faculté des Sciences, UQAM, Montréal, QC H2X 1Y4, Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal, Montréal, QC H3W 1W5, Canada
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16
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Philp AM, Saner NJ, Lazarou M, Ganley IG, Philp A. The influence of aerobic exercise on mitochondrial quality control in skeletal muscle. J Physiol 2021; 599:3463-3476. [PMID: 33369731 DOI: 10.1113/jp279411] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 12/17/2020] [Indexed: 01/12/2023] Open
Abstract
Mitochondria are dynamic organelles, intricately designed to meet cellular energy requirements. To accommodate alterations in energy demand, mitochondria have a high degree of plasticity, changing in response to transient activation of numerous stress-related pathways. This adaptive response is particularly relevant in highly metabolic tissues such as skeletal muscle, where mitochondria support numerous biological processes related to metabolism, growth and regeneration. Aerobic exercise is a potent stimulus for skeletal muscle remodelling, leading to alterations in substrate utilisation, fibre-type composition and performance. Underlying these physiological responses is a change in mitochondrial quality control (MQC), a term encompassing the co-ordination of mitochondrial synthesis (biogenesis), remodelling (dynamics) and degradation (mitophagy) pathways. Understanding of MQC in skeletal muscle and the regulatory role of aerobic exercise of this process are rapidly advancing, as are the molecular techniques allowing the study of MQC in vivo. Given the emerging link between MQC and the onset of numerous non-communicable diseases, understanding the molecular regulation of MQC, and the role of aerobic exercise in this process, will have substantial future impact on therapeutic approaches to manipulate MQC and maintain mitochondrial function across health span.
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Affiliation(s)
- Ashleigh M Philp
- Healthy Ageing Research Theme, Garvan Institute of Medical Research, 384 Victoria Street, Sydney, New South Wales, 2010, Australia
- St Vincent's Medical School, UNSW Medicine, UNSW Sydney, Sydney, New South Wales, 2010, Australia
| | - Nicholas J Saner
- Sports Cardiology, Baker Heart and Diabetes Institute, Melbourne, Australia
| | - Michael Lazarou
- Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Ian G Ganley
- Medical Research Council Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, UK
| | - Andrew Philp
- Healthy Ageing Research Theme, Garvan Institute of Medical Research, 384 Victoria Street, Sydney, New South Wales, 2010, Australia
- St Vincent's Medical School, UNSW Medicine, UNSW Sydney, Sydney, New South Wales, 2010, Australia
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17
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Michelucci A, Liang C, Protasi F, Dirksen RT. Altered Ca 2+ Handling and Oxidative Stress Underlie Mitochondrial Damage and Skeletal Muscle Dysfunction in Aging and Disease. Metabolites 2021; 11:metabo11070424. [PMID: 34203260 PMCID: PMC8304741 DOI: 10.3390/metabo11070424] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/22/2021] [Accepted: 06/24/2021] [Indexed: 12/26/2022] Open
Abstract
Skeletal muscle contraction relies on both high-fidelity calcium (Ca2+) signals and robust capacity for adenosine triphosphate (ATP) generation. Ca2+ release units (CRUs) are highly organized junctions between the terminal cisternae of the sarcoplasmic reticulum (SR) and the transverse tubule (T-tubule). CRUs provide the structural framework for rapid elevations in myoplasmic Ca2+ during excitation-contraction (EC) coupling, the process whereby depolarization of the T-tubule membrane triggers SR Ca2+ release through ryanodine receptor-1 (RyR1) channels. Under conditions of local or global depletion of SR Ca2+ stores, store-operated Ca2+ entry (SOCE) provides an additional source of Ca2+ that originates from the extracellular space. In addition to Ca2+, skeletal muscle also requires ATP to both produce force and to replenish SR Ca2+ stores. Mitochondria are the principal intracellular organelles responsible for ATP production via aerobic respiration. This review provides a broad overview of the literature supporting a role for impaired Ca2+ handling, dysfunctional Ca2+-dependent production of reactive oxygen/nitrogen species (ROS/RNS), and structural/functional alterations in CRUs and mitochondria in the loss of muscle mass, reduction in muscle contractility, and increase in muscle damage in sarcopenia and a wide range of muscle disorders including muscular dystrophy, rhabdomyolysis, central core disease, and disuse atrophy. Understanding the impact of these processes on normal muscle function will provide important insights into potential therapeutic targets designed to prevent or reverse muscle dysfunction during aging and disease.
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Affiliation(s)
- Antonio Michelucci
- DNICS, Department of Neuroscience, Imaging, and Clinical Sciences, University G. d’Annunzio of Chieti-Pescara, I-66100 Chieti, Italy
- Correspondence:
| | - Chen Liang
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA; (C.L.); (R.T.D.)
| | - Feliciano Protasi
- CAST, Center for Advanced Studies and Technology, DMSI, Department of Medicine and Aging Sciences, University G. d’Annunzio of Chieti-Pescara, I-66100 Chieti, Italy;
| | - Robert T. Dirksen
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, NY 14642, USA; (C.L.); (R.T.D.)
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18
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Abstract
As the powerhouse of the cell, mitochondria, plays a crucial role in many aspects of life, whereby mitochondrial dysfunctions are associated with pathogenesis of many diseases, like neurodegenerative diseases, obesity, cancer, and metabolic as well as cardiovascular disorders. Mitochondria analysis frequently starts with isolation and enrichment procedures, which have become increasingly important in biomedical research. Unfortunately, isolation procedures can easily cause changes in the structural integrity of mitochondria during in vitro handling having impact on their function. This carries the risk that conclusions about isolated mitochondria may be drawn on the basis of experimental artifacts. Here we critically review a commonly used isolation procedure for mitochondria utilizing differential (gradient) centrifugation and depict major challenges to achieve "functional" mitochondria as basis for comprehensive physiological studies.
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Affiliation(s)
- Stefan Lehr
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, Duesseldorf, Germany.
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.
| | - Sonja Hartwig
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, Duesseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Jorg Kotzka
- Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center at the Heinrich-Heine-University Duesseldorf, Leibniz Center for Diabetes Research, Duesseldorf, Germany
- German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
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19
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De Mario A, Gherardi G, Rizzuto R, Mammucari C. Skeletal muscle mitochondria in health and disease. Cell Calcium 2021; 94:102357. [PMID: 33550207 DOI: 10.1016/j.ceca.2021.102357] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/07/2021] [Accepted: 01/07/2021] [Indexed: 12/28/2022]
Abstract
Mitochondrial activity warrants energy supply to oxidative myofibres to sustain endurance workload. The maintenance of mitochondrial homeostasis is ensured by the control of fission and fusion processes and by the mitophagic removal of aberrant organelles. Many diseases are due to or characterized by dysfunctional mitochondria, and altered mitochondrial dynamics or turnover trigger myopathy per se. In this review, we will tackle the role of mitochondrial dynamics, turnover and metabolism in skeletal muscle, both in health and disease.
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Affiliation(s)
- Agnese De Mario
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Gaia Gherardi
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padua, Padua, Italy
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20
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Memme JM, Hood DA. Molecular Basis for the Therapeutic Effects of Exercise on Mitochondrial Defects. Front Physiol 2021; 11:615038. [PMID: 33584337 PMCID: PMC7874077 DOI: 10.3389/fphys.2020.615038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/16/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial dysfunction is common to many organ system disorders, including skeletal muscle. Aging muscle and diseases of muscle are often accompanied by defective mitochondrial ATP production. This manuscript will focus on the pre-clinical evidence supporting the use of regular exercise to improve defective mitochondrial metabolism and function in skeletal muscle, through the stimulation of mitochondrial turnover. Examples from aging muscle, muscle-specific mutations and cancer cachexia will be discussed. We will also examine the effects of exercise on the important mitochondrial regulators PGC-1α, and Parkin, and summarize the effects of exercise to reverse mitochondrial dysfunction (e.g., ROS production, apoptotic susceptibility, cardiolipin synthesis) in muscle pathology. This paper will illustrate the breadth and benefits of exercise to serve as "mitochondrial medicine" with age and disease.
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Affiliation(s)
- Jonathan M. Memme
- Muscle Health Research Centre, York University, Toronto, ON, Canada
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - David A. Hood
- Muscle Health Research Centre, York University, Toronto, ON, Canada
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
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21
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Liu F, Zhang L, Li F, Zhang X, Zou L, Chai J, Xin X, Xu J, Zhang G. A noteworthy interface-targeting fluorescent probe for long-term tracking mitochondria and visualizing mitophagy. Biosens Bioelectron 2020; 168:112526. [DOI: 10.1016/j.bios.2020.112526] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 08/16/2020] [Accepted: 08/18/2020] [Indexed: 12/20/2022]
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22
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Alam S, Abdullah CS, Aishwarya R, Morshed M, Bhuiyan MS. Molecular Perspectives of Mitochondrial Adaptations and Their Role in Cardiac Proteostasis. Front Physiol 2020; 11:1054. [PMID: 32982788 PMCID: PMC7481364 DOI: 10.3389/fphys.2020.01054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 07/31/2020] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are the key to properly functioning energy generation in the metabolically demanding cardiomyocytes and thus essential to healthy heart contractility on a beat-to-beat basis. Mitochondria being the central organelle for cellular metabolism and signaling in the heart, its dysfunction leads to cardiovascular disease. The healthy mitochondrial functioning critical to maintaining cardiomyocyte viability and contractility is accomplished by adaptive changes in the dynamics, biogenesis, and degradation of the mitochondria to ensure cellular proteostasis. Recent compelling evidence suggests that the classical protein quality control system in cardiomyocytes is also under constant mitochondrial control, either directly or indirectly. Impairment of cytosolic protein quality control may affect the position of the mitochondria in relation to other organelles, as well as mitochondrial morphology and function, and could also activate mitochondrial proteostasis. Despite a growing interest in the mitochondrial quality control system, very little information is available about the molecular function of mitochondria in cardiac proteostasis. In this review, we bring together current understanding of the adaptations and role of the mitochondria in cardiac proteostasis and describe the adaptive/maladaptive changes observed in the mitochondrial network required to maintain proteomic integrity. We also highlight the key mitochondrial signaling pathways activated in response to proteotoxic stress as a cellular mechanism to protect the heart from proteotoxicity. A deeper understanding of the molecular mechanisms of mitochondrial adaptations and their role in cardiac proteostasis will help to develop future therapeutics to protect the heart from cardiovascular diseases.
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Affiliation(s)
- Shafiul Alam
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA, United States
| | - Chowdhury S Abdullah
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA, United States
| | - Richa Aishwarya
- Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, United States
| | - Mahboob Morshed
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA, United States
| | - Md Shenuarin Bhuiyan
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA, United States.,Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center, Shreveport, LA, United States
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23
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Ferri E, Marzetti E, Calvani R, Picca A, Cesari M, Arosio B. Role of Age-Related Mitochondrial Dysfunction in Sarcopenia. Int J Mol Sci 2020; 21:ijms21155236. [PMID: 32718064 PMCID: PMC7432902 DOI: 10.3390/ijms21155236] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/15/2020] [Accepted: 07/22/2020] [Indexed: 02/06/2023] Open
Abstract
Skeletal muscle aging is associated with a significant loss of skeletal muscle strength and power (i.e., dynapenia), muscle mass and quality of life, a phenomenon known as sarcopenia. This condition affects nearly one-third of the older population and is one of the main factors leading to negative health outcomes in geriatric patients. Notwithstanding the exact mechanisms responsible for sarcopenia are not fully understood, mitochondria have emerged as one of the central regulators of sarcopenia. In fact, there is a wide consensus on the assumption that the loss of mitochondrial integrity in myocytes is the main factor leading to muscle degeneration. Mitochondria are also key players in senescence. It has been largely proven that the modulation of mitochondrial functions can induce the death of senescent cells and that removal of senescent cells improves musculoskeletal health, quality, and function. In this review, the crosstalk among mitochondria, cellular senescence, and sarcopenia will be discussed with the aim to elucidate the role that the musculoskeletal cellular senescence may play in the onset of sarcopenia through the mediation of mitochondria.
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Affiliation(s)
- Evelyn Ferri
- Geriatric Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (M.C.); (B.A.)
- Correspondence:
| | - Emanuele Marzetti
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (E.M.); (R.C.); (A.P.)
- Geriatric Unit, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Riccardo Calvani
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (E.M.); (R.C.); (A.P.)
- Geriatric Unit, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Anna Picca
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (E.M.); (R.C.); (A.P.)
- Geriatric Unit, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Matteo Cesari
- Geriatric Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (M.C.); (B.A.)
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| | - Beatrice Arosio
- Geriatric Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (M.C.); (B.A.)
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
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24
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Defective endoplasmic reticulum-mitochondria contacts and bioenergetics in SEPN1-related myopathy. Cell Death Differ 2020; 28:123-138. [PMID: 32661288 PMCID: PMC7853070 DOI: 10.1038/s41418-020-0587-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/11/2020] [Accepted: 06/25/2020] [Indexed: 01/19/2023] Open
Abstract
SEPN1-related myopathy (SEPN1-RM) is a muscle disorder due to mutations of the SEPN1 gene, which is characterized by muscle weakness and fatigue leading to scoliosis and life-threatening respiratory failure. Core lesions, focal areas of mitochondria depletion in skeletal muscle fibers, are the most common histopathological lesion. SEPN1-RM underlying mechanisms and the precise role of SEPN1 in muscle remained incompletely understood, hindering the development of biomarkers and therapies for this untreatable disease. To investigate the pathophysiological pathways in SEPN1-RM, we performed metabolic studies, calcium and ATP measurements, super-resolution and electron microscopy on in vivo and in vitro models of SEPN1 deficiency as well as muscle biopsies from SEPN1-RM patients. Mouse models of SEPN1 deficiency showed marked alterations in mitochondrial physiology and energy metabolism, suggesting that SEPN1 controls mitochondrial bioenergetics. Moreover, we found that SEPN1 was enriched at the mitochondria-associated membranes (MAM), and was needed for calcium transients between ER and mitochondria, as well as for the integrity of ER-mitochondria contacts. Consistently, loss of SEPN1 in patients was associated with alterations in body composition which correlated with the severity of muscle weakness, and with impaired ER-mitochondria contacts and low ATP levels. Our results indicate a role of SEPN1 as a novel MAM protein involved in mitochondrial bioenergetics. They also identify a systemic bioenergetic component in SEPN1-RM and establish mitochondria as a novel therapeutic target. This role of SEPN1 contributes to explain the fatigue and core lesions in skeletal muscle as well as the body composition abnormalities identified as part of the SEPN1-RM phenotype. Finally, these results point out to an unrecognized interplay between mitochondrial bioenergetics and ER homeostasis in skeletal muscle. They could therefore pave the way to the identification of biomarkers and therapeutic drugs for SEPN1-RM and for other disorders in which muscle ER-mitochondria cross-talk are impaired.
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25
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Rexius-Hall ML, Khalil NN, Andres AM, McCain ML. Mitochondrial division inhibitor 1 (mdivi-1) increases oxidative capacity and contractile stress generated by engineered skeletal muscle. FASEB J 2020; 34:11562-11576. [PMID: 32652761 DOI: 10.1096/fj.201901039rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/03/2020] [Accepted: 06/08/2020] [Indexed: 12/16/2022]
Abstract
In skeletal muscle fibers, mitochondria are densely packed adjacent to myofibrils because adenosine triphosphate (ATP) is needed to fuel sarcomere shortening. However, despite this close physical and biochemical relationship, the effects of mitochondrial dynamics on skeletal muscle contractility are poorly understood. In this study, we analyzed the effects of Mitochondrial Division Inhibitor 1 (mdivi-1), an inhibitor of mitochondrial fission, on the structure and function of both mitochondria and myofibrils in skeletal muscle tissues engineered on micromolded gelatin hydrogels. Treatment with mdivi-1 did not alter myotube morphology, but did increase the mitochondrial turbidity and oxidative capacity, consistent with reduced mitochondrial fission. Mdivi-1 also significantly increased basal, twitch, and tetanus stresses, as measured using the Muscular Thin Film (MTF) assay. Finally, mdivi-1 increased sarcomere length, potentially due to mdivi-1-induced changes in mitochondrial volume and compression of myofibrils. Together, these results suggest that mdivi-1 increases contractile stress generation, which may be caused by an increase in maximal respiration and/or sarcomere length due to increased volume of individual mitochondria. These data reinforce that mitochondria have both biochemical and biomechanical roles in skeletal muscle and that mitochondrial dynamics can be manipulated to alter muscle contractility.
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Affiliation(s)
- Megan L Rexius-Hall
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Natalie N Khalil
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Allen M Andres
- Smidt Heart Institute and Barbra Streisand Women's Heart Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Megan L McCain
- Laboratory for Living Systems Engineering, Department of Biomedical Engineering, USC Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA.,Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine of USC, University of Southern California, Los Angeles, CA, USA
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26
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Fiorani M, Scotti M, Guidarelli A, Burattini S, Falcieri E, Cantoni O. SVCT2-Dependent plasma and mitochondrial membrane transport of ascorbic acid in differentiating myoblasts. Pharmacol Res 2020; 159:105042. [PMID: 32580031 DOI: 10.1016/j.phrs.2020.105042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 06/17/2020] [Accepted: 06/17/2020] [Indexed: 12/14/2022]
Abstract
The Na+-dependent Vitamin C transporter 2 (SVCT2) is expressed in the plasma and mitochondrial membranes of various cell types. This notion was also established in proliferating C2C12 myoblasts (Mb), in which the transporter was characterised by a high and low affinity in the plasma and mitochondrial membranes, respectively. In addition, the mitochondrial expression of SVCT2 appeared particularly elevated and, consistently, a brief pre-exposure to low concentrations of Ascorbic Acid (AA) abolished mitochondrial superoxide formation selectively induced by the cocktail arsenite/ATP. Early myotubes (Mt) derived from these cells after 4 days of differentiation presented evidence of slightly increased SVCT2 expression, and were characterised by kinetic parameters for plasma membrane transport of AA in line with those detected in Mb. Confocal microscopy studies indicated that the mitochondrial expression of SVCT2 is well preserved in Mt with one or two nuclei, but progressively reduced in Mt with three or more nuclei. Cellular and mitochondrial expression of SVCT2 was found reduced in day 7 Mt. While the uptake studies were compromised by the poor purity of the mitochondrial preparations obtained from day 4 Mt, we nevertheless obtained evidence of poor transport of the vitamin using the same functional studies successfully employed with Mb. Indeed, even greater concentrations of/longer pre-exposure to AA failed to induce scavenging of mitochondrial superoxide in Mt. These results are therefore indicative of a severely reduced mitochondrial uptake of the vitamin in early Mt, attributable to decreased expression as well as impaired activity of mitochondrial SVCT2.
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Affiliation(s)
- Mara Fiorani
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Maddalena Scotti
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Andrea Guidarelli
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Sabrina Burattini
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Elisabetta Falcieri
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
| | - Orazio Cantoni
- Dipartimento di Scienze Biomolecolari, Università degli Studi di Urbino Carlo Bo, 61029 Urbino, Italy.
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Vesicular transport mediates the uptake of cytoplasmic proteins into mitochondria in Drosophila melanogaster. Nat Commun 2020; 11:2592. [PMID: 32444642 PMCID: PMC7244744 DOI: 10.1038/s41467-020-16335-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 04/27/2020] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial aging, which results in mitochondrial dysfunction, is strongly linked to many age-related diseases. Aging is associated with mitochondrial enlargement and transport of cytosolic proteins into mitochondria. The underlying homeostatic mechanisms that regulate mitochondrial morphology and function, and their breakdown during aging, remain unclear. Here, we identify a mitochondrial protein trafficking pathway in Drosophila melanogaster involving the mitochondria-associated protein Dosmit. Dosmit induces mitochondrial enlargement and the formation of double-membraned vesicles containing cytosolic protein within mitochondria. The rate of vesicle formation increases with age. Vesicles originate from the outer mitochondrial membrane as observed by tracking Tom20 localization, and the process is mediated by the mitochondria-associated Rab32 protein. Dosmit expression level is closely linked to the rate of ubiquitinated protein aggregation, which are themselves associated with age-related diseases. The mitochondrial protein trafficking route mediated by Dosmit offers a promising target for future age-related mitochondrial disease therapies. Mitochondrial dynamics change during ageing, with larger mitochondria and altered protein import in older animals. Here the authors show that Dosmit protein mediates mitochondrial morphology with Rab32 by inducing double-membraned vesicles that regulate protein trafficking into mitochondria.
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Boncompagni S, Pozzer D, Viscomi C, Ferreiro A, Zito E. Physical and Functional Cross Talk Between Endo-Sarcoplasmic Reticulum and Mitochondria in Skeletal Muscle. Antioxid Redox Signal 2020; 32:873-883. [PMID: 31825235 DOI: 10.1089/ars.2019.7934] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Significance: The physiological relevance of contacts between the sarcoplasmic reticulum (SR), a specialized domain of the endoplasmic reticulum (ER) in skeletal muscle, and mitochondria is still not clear. Recent Advances: An extensive close proximity of these two organelles is a late developmental event, which suggests that it does not have an essential function. Critical Issues: The intimate association of SR/mitochondria develops during murine postnatal differentiation and the recovery of denervated atrophic muscle, which suggests that this is a highly regulated process with a specific function. Analyses of mouse models for muscle diseases suggest that impaired ER/SR-mitochondrial contacts may be due to ER stress and lead to defective bioenergetics and insulin signaling. Future Directions: Future studies are necessary to identify the molecular determinants weakening insulin signaling upon impairment of ER/mitochondrial contacts in skeletal muscles as well as to analyze the distance between SR/ER and mitochondria in muscle diseases associated with ER stress.
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Affiliation(s)
- Simona Boncompagni
- CeSI-Met-Center for Research on Ageing and Translational Medicine, University G. d' Annunzio, Chieti, Italy.,DNICS-Department of Neuroscience, Imaging and Clinical Sciences, University G. d' Annunzio, Chieti, Italy
| | - Diego Pozzer
- Istituto di Ricerche Farmacologiche Mario Negri-IRCCS, Milan, Italy
| | - Carlo Viscomi
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Ana Ferreiro
- Unit of Functional and Adaptive Biology, BFA, Pathophysiology of Striated Muscles Laboratory, University Paris Diderot/CNRS, Sorbonne Paris Cité, Paris, France.,AP-HP, Centre de Référence Maladies Neuromusculaires Paris-Est, Groupe Hospitalier Pitié-Salpêtrière, Paris, France
| | - Ester Zito
- Istituto di Ricerche Farmacologiche Mario Negri-IRCCS, Milan, Italy
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29
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Raz Y, Akker EB, Roest T, Riaz M, Rest O, Suchiman HED, Lakenberg N, Stassen SA, Putten M, Feskens EJM, Reinders MJT, Goeman J, Beekman M, Raz V, Slagboom PE. A data‐driven methodology reveals novel myofiber clusters in older human muscles. FASEB J 2020; 34:5525-5537. [DOI: 10.1096/fj.201902350r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 01/07/2020] [Accepted: 02/13/2020] [Indexed: 01/08/2023]
Affiliation(s)
- Yotam Raz
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Erik B. Akker
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
- Leiden Computational Biology Center Leiden University Medical Center Leiden the Netherlands
- The Delft Bioinformatics Lab Delft University of Technology Delft the Netherlands
| | - Tijmen Roest
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Muhammad Riaz
- Department of Human Genetics Leiden University Medical Center Leiden the Netherlands
| | - Ondine Rest
- Division of Human Nutrition Wageningen University & Research Wageningen the Netherlands
| | - H. Eka D. Suchiman
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Nico Lakenberg
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Stefanie A. Stassen
- Section of Gerontology and Geriatrics Leiden University Medical Center Leiden the Netherlands
| | - Maaike Putten
- Department of Human Genetics Leiden University Medical Center Leiden the Netherlands
| | - Edith J. M. Feskens
- Division of Human Nutrition Wageningen University & Research Wageningen the Netherlands
| | - Marcel J. T. Reinders
- Leiden Computational Biology Center Leiden University Medical Center Leiden the Netherlands
- The Delft Bioinformatics Lab Delft University of Technology Delft the Netherlands
| | - Jelle Goeman
- Department of Medical Statistics Leiden University Medical Center Leiden the Netherlands
| | - Marian Beekman
- Section of Molecular Epidemiology Leiden University Medical Center Leiden the Netherlands
| | - Vered Raz
- Department of Human Genetics Leiden University Medical Center Leiden the Netherlands
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30
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Sébastien M, Aubin P, Brocard J, Brocard J, Marty I, Fauré J. Dynamics of triadin, a muscle-specific triad protein, within sarcoplasmic reticulum subdomains. Mol Biol Cell 2020; 31:261-272. [PMID: 31877066 PMCID: PMC7183767 DOI: 10.1091/mbc.e19-07-0399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
In skeletal muscle, proteins of the calcium release complex responsible for the excitation-contraction (EC) coupling are exclusively localized in specific reticulum–plasma membrane (ER-PM) contact points named triads. The CRC protein triadin (T95) is localized in the sarcoplasmic reticulum (SR) subdomain of triads where it forms large multimers. However, the mechanisms leading to the steady-state accumulation of T95 in these specific areas of SR are largely unknown. To visualize T95 dynamics, fluorescent chimeras were expressed in triadin knockout myotubes, and their mobility was compared with the mobility of Sec61β, a membrane protein of the SR unrelated to the EC coupling process. At all stages of skeletal muscle cells differentiation, we show a permanent flux of T95 diffusing in the SR membrane. Moreover, we find evidence that a longer residence time in the ER-PM contact point is due to the transmembrane domain of T95 resulting in an overall triad localization.
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Affiliation(s)
- Muriel Sébastien
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Perrine Aubin
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Jacques Brocard
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Julie Brocard
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Isabelle Marty
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
| | - Julien Fauré
- Grenoble Institut Neurosciences, Inserm, U1216, University Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France.,Grenoble Institut Neurosciences, Inserm, U1216, CHU Grenoble Alpes, University Grenoble Alpes, 38000 Grenoble, France
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31
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Stacchiotti A, Favero G, Rodella LF. Impact of Melatonin on Skeletal Muscle and Exercise. Cells 2020; 9:cells9020288. [PMID: 31991655 PMCID: PMC7072499 DOI: 10.3390/cells9020288] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/14/2020] [Accepted: 01/22/2020] [Indexed: 12/18/2022] Open
Abstract
Skeletal muscle disorders are dramatically increasing with human aging with enormous sanitary costs and impact on the quality of life. Preventive and therapeutic tools to limit onset and progression of muscle frailty include nutrition and physical training. Melatonin, the indole produced at nighttime in pineal and extra-pineal sites in mammalians, has recognized anti-aging, anti-inflammatory, and anti-oxidant properties. Mitochondria are the favorite target of melatonin, which maintains them efficiently, scavenging free radicals and reducing oxidative damage. Here, we discuss the most recent evidence of dietary melatonin efficacy in age-related skeletal muscle disorders in cellular, preclinical, and clinical studies. Furthermore, we analyze the emerging impact of melatonin on physical activity. Finally, we consider the newest evidence of the gut-muscle axis and the influence of exercise and probably melatonin on the microbiota. In our opinion, this review reinforces the relevance of melatonin as a safe nutraceutical that limits skeletal muscle frailty and prolongs physical performance.
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Affiliation(s)
- Alessandra Stacchiotti
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy; (G.F.); (L.F.R.)
- Interdepartmental University Center of Research “Adaptation and Regeneration of Tissues and Organs (ARTO)”, University of Brescia, 25123 Brescia, Italy
- Correspondence: ; Tel.: +39-030-3717478; Fax: +39-030-3717486
| | - Gaia Favero
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy; (G.F.); (L.F.R.)
| | - Luigi Fabrizio Rodella
- Anatomy and Physiopathology Division, Department of Clinical and Experimental Sciences, University of Brescia, Viale Europa 11, 25123 Brescia, Italy; (G.F.); (L.F.R.)
- Interdepartmental University Center of Research “Adaptation and Regeneration of Tissues and Organs (ARTO)”, University of Brescia, 25123 Brescia, Italy
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32
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Anagnostou ME, Hepple RT. Mitochondrial Mechanisms of Neuromuscular Junction Degeneration with Aging. Cells 2020; 9:cells9010197. [PMID: 31941062 PMCID: PMC7016881 DOI: 10.3390/cells9010197] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/11/2022] Open
Abstract
Skeletal muscle deteriorates with aging, contributing to physical frailty, poor health outcomes, and increased risk of mortality. Denervation is a major driver of changes in aging muscle. This occurs through transient denervation-reinnervation events throughout the aging process that remodel the spatial domain of motor units and alter fiber type. In advanced age, reinnervation wanes, leading to persistent denervation that accelerates muscle atrophy and impaired muscle contractility. Alterations in the muscle fibers and motoneurons are both likely involved in driving denervation through destabilization of the neuromuscular junction. In this respect, mitochondria are implicated in aging and age-related neurodegenerative disorders, and are also likely key to aging muscle changes through their direct effects in muscle fibers and through secondary effects mediated by mitochondrial impairments in motoneurons. Indeed, the large abundance of mitochondria in muscle fibers and motoneurons, that are further concentrated on both sides of the neuromuscular junction, likely renders the neuromuscular junction especially vulnerable to age-related mitochondrial dysfunction. Manifestations of mitochondrial dysfunction with aging include impaired respiratory function, elevated reactive oxygen species production, and increased susceptibility to permeability transition, contributing to reduced ATP generating capacity, oxidative damage, and apoptotic signaling, respectively. Using this framework, in this review we summarize our current knowledge, and relevant gaps, concerning the potential impact of mitochondrial impairment on the aging neuromuscular junction, and the mechanisms involved.
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33
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Memme JM, Erlich AT, Phukan G, Hood DA. Exercise and mitochondrial health. J Physiol 2019; 599:803-817. [PMID: 31674658 DOI: 10.1113/jp278853] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/28/2019] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial health is an important mediator of cellular function across a range of tissues, and as a result contributes to whole-body vitality in health and disease. Our understanding of the regulation and function of these organelles is of great interest to scientists and clinicians across many disciplines within our healthcare system. Skeletal muscle is a useful model tissue for the study of mitochondrial adaptations because of its mass and contribution to whole body metabolism. The remarkable plasticity of mitochondria allows them to adjust their volume, structure and capacity under conditions such as exercise, which is useful or improving metabolic health in individuals with various diseases and/or advancing age. Mitochondria exist within muscle as a functional reticulum which is maintained by dynamic processes of biogenesis and fusion, and is balanced by opposing processes of fission and mitophagy. The sophisticated coordination of these events is incompletely understood, but is imperative for organelle function and essential for the maintenance of an interconnected organelle network that is finely tuned to the metabolic needs of the cell. Further elucidation of the mechanisms of mitochondrial turnover in muscle could offer potential therapeutic targets for the advancement of health and longevity among our ageing populations. As well, investigating exercise modalities that are both convenient and capable of inducing robust mitochondrial adaptations are useful in fostering more widespread global adherence. To this point, exercise remains the most potent behavioural therapeutic approach for the improvement of mitochondrial health, not only in muscle, but potentially also in other tissues.
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Affiliation(s)
- Jonathan M Memme
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada, M3J 1P3.,School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada, M3J 1P3
| | - Avigail T Erlich
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada, M3J 1P3.,School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada, M3J 1P3
| | - Geetika Phukan
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada, M3J 1P3.,School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada, M3J 1P3
| | - David A Hood
- Muscle Health Research Centre, York University, Toronto, Ontario, Canada, M3J 1P3.,School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada, M3J 1P3
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34
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Quintana-Villamandos B, Delgado-Martos MJ, Delgado-Baeza E. Early reversal cardiac with esmolol in hypertensive rats: The role of subcellular organelle phenotype. Pharmacol Rep 2019; 71:1125-1132. [PMID: 31648130 DOI: 10.1016/j.pharep.2019.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Revised: 06/08/2019] [Accepted: 06/28/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Our group has previously shown that short-term treatment (48 h) with esmolol reduces left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHRs). However, we do not know the mechanism that explain this effect. The aim of this study was to assess the role that the subcellular organelle phenotype plays in early cardiac reverse after short-term treatment with esmolol. METHODS 14-Month-old male SHRs were randomly assigned to receive esmolol (300 μg/kg/min) (SHR-E) or vehicle (SHR). Age-matched male Wistar-Kyoto rats (WKY) served as controls. After 48 h of treatment, an ultrastructural analysis of heart tissue (left ventricle) was performed. We studied cardiomyocyte ultrastructural remodeling of subcellular organelles by electronic microcopy in all groups. RESULTS SHR group showed significant morphometric and stereological changes in mitochondria and subcellular organelles (cytoplasm and nucleus, myofibril structure, mitochondria structure, Z-Disk, intercalated disk, T-system and cystern), and also changes in the extracellular matrix (collagen) with respect to WKY group. Esmolol significantly improved the morphology and stereology mitochondrial, reduced the organelle phenotype abnormalities but no produced changes in the extracellular matrix with respect to SHR group. Interesantly, parameters of mitochondria (regularity factor, ellipsoidal form factor and density of volume), and all parameters of subcellular organelles returned to the normality in SHR-E. CONCLUSION Our results show that left ventricular hypertrophy reversal after short-term treatment with esmolol is associated with reversal of subcellular organelle phenotype.
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Affiliation(s)
- Begoña Quintana-Villamandos
- Department of Anesthesiology, Reanimation and Intensive Care, Hospital General Universitario Gregorio Marañón, Madrid, Spain; Department of Pharmacology and Toxicology, Universidad Complutense de Madrid, Spain.
| | - María Jesús Delgado-Martos
- Molecular Biology Laboratory, Department Experimental Medicine and Surgery, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain; Department of Biomedicine, Universidad Francisco de Vitoria, Madrid, Spain
| | - Emilio Delgado-Baeza
- Molecular Biology Laboratory, Department Experimental Medicine and Surgery, Instituto de Investigación Sanitaria Gregorio Marañón, Madrid, Spain
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35
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Mitochondrial Structural Changes in the Pathogenesis of Diabetic Retinopathy. J Clin Med 2019; 8:jcm8091363. [PMID: 31480638 PMCID: PMC6780143 DOI: 10.3390/jcm8091363] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 08/27/2019] [Accepted: 08/29/2019] [Indexed: 12/24/2022] Open
Abstract
At the core of proper mitochondrial functionality is the maintenance of its structure and morphology. Physical changes in mitochondrial structure alter metabolic pathways inside mitochondria, affect mitochondrial turnover, disturb mitochondrial dynamics, and promote mitochondrial fragmentation, ultimately triggering apoptosis. In high glucose condition, increased mitochondrial fragmentation contributes to apoptotic death in retinal vascular and Müller cells. Although alterations in mitochondrial morphology have been detected in several diabetic tissues, it remains to be established in the vascular cells of the diabetic retina. From a mechanistic standpoint, our current work supports the notion that increased expression of fission genes and decreased expression of fusion genes are involved in promoting excessive mitochondrial fragmentation. While mechanistic insights are only beginning to reveal how high glucose alters mitochondrial morphology, the consequences are clearly seen as release of cytochrome c from fragmented mitochondria triggers apoptosis. Current findings raise the prospect of targeting excessive mitochondrial fragmentation as a potential therapeutic strategy for treatment of diabetic retinopathy. While biochemical and epigenetic changes have been reported to be associated with mitochondrial dysfunction, this review focuses on alterations in mitochondrial morphology, and their impact on mitochondrial function and pathogenesis of diabetic retinopathy.
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36
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Sparc, an EPS-induced gene, modulates the extracellular matrix and mitochondrial function via ILK/AMPK pathways in C2C12 cells. Life Sci 2019; 229:277-287. [DOI: 10.1016/j.lfs.2019.05.070] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2019] [Revised: 05/24/2019] [Accepted: 05/27/2019] [Indexed: 01/06/2023]
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37
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Böl M, Iyer R, Dittmann J, Garcés-Schröder M, Dietzel A. Investigating the passive mechanical behaviour of skeletal muscle fibres: Micromechanical experiments and Bayesian hierarchical modelling. Acta Biomater 2019; 92:277-289. [PMID: 31077887 DOI: 10.1016/j.actbio.2019.05.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/24/2019] [Accepted: 05/06/2019] [Indexed: 02/06/2023]
Abstract
Characterisation of the skeletal muscle's passive properties is a challenging task since its structure is dominated by a highly complex and hierarchical arrangement of fibrous components at different scales. The present work focuses on the micromechanical characterisation of skeletal muscle fibres, which consist of myofibrils, by realising three different deformation states, namely, axial tension, axial compression, and transversal compression. To the best of the authors' knowledge, the present study provides a novel comprehensive data set representing of different deformation states. These data allow for a better understanding of muscle fibre load transfer mechanisms and can be used for meaningful modelling approaches. As the present study shows, axial tension and compression experiments reveal a strong tension-compression asymmetry at fibre level. In comparison to the tissue level, this asymmetric behaviour is more pronounced at the fibre scale, elucidating the load transfer mechanism in muscle tissue and aiding in the development of future modelling strategies. Further, a Bayesian hierarchical modelling approach was used to consider the experimental fluctuations in a parameter identification scheme, leading to more comprehensive parameter distributions that reflect the entire observed experimental uncertainty. STATEMENT OF SIGNIFICANCE: This article examines for the first time the mechanical properties of skeletal muscle fibres under axial tension, axial compression, and transversal compression, leading to a highly comprehensive data set. Moreover, a Bayesian hierarchical modelling concept is presented to identify model parameters in a broad way. The results of the deformation states allow a new and comprehensive understanding of muscle fibres' load transfer mechanisms; one example is the effect of tension-compression asymmetry. On the one hand, the results of this study contribute to the understanding of muscle mechanics and thus to the muscle's functional understanding during daily activity. On the other hand, they are relevant in the fields of skeletal muscle multiscale, constitutive modelling.
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Affiliation(s)
- Markus Böl
- Institute of Solid Mechanics, Technische Universität Braunschweig, Braunschweig D-38106, Germany.
| | - Rahul Iyer
- Institute of Solid Mechanics, Technische Universität Braunschweig, Braunschweig D-38106, Germany
| | - Johannes Dittmann
- Institute of Solid Mechanics, Technische Universität Braunschweig, Braunschweig D-38106, Germany
| | - Mayra Garcés-Schröder
- Institute of Micro Technology, Technische Universität Braunschweig, Braunschweig D-38124, Germany
| | - Andreas Dietzel
- Institute of Micro Technology, Technische Universität Braunschweig, Braunschweig D-38124, Germany
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38
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Rusu MC, Nicolescu MI, Jianu AM, Mănoiu VS, Ilie AC, Dincă D. The ultrastructural anatomy of the nuclear envelope in the masseter muscle indicates its role in the metabolism of the intracellular Ca +. Ann Anat 2019; 224:117-123. [PMID: 31117003 DOI: 10.1016/j.aanat.2019.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 04/05/2019] [Accepted: 05/06/2019] [Indexed: 11/16/2022]
Abstract
Specific ultrastructural anatomy of masticatory muscles is commonly referred to a general pattern assigned to striated muscles. Junctional feet consisting of calcium channels of the sarcoplasmic reticulum (i.e. the ryanodine receptors, RyRs) physically connected to the calcium channels of the t-tubules build triads within striated muscles. Functional RyRs were demonstrated in the nuclear envelopes of pancreas and of a skeletal muscle derived cell line, but not in muscle in situ. It was hypothesized that ryanodine receptors (RyRs) could also exist in the nuclear envelope in the masseter muscle, thus aiming at studying this by transmission electron microscopy. There were identified paired and consistent subsarcolemmal clusters of mitochondria, appearing as outpockets of the muscle fibers, usually flanking an endomysial microvessel. It was observed on grazing longitudinal cuts that the I-band-limited mitochondria were not strictly located in a single intermyofibrillar space but continued transversally over the I-band to the next intermyofibrillar space. It appeared that the I-band-limited transverse mitochondria participate with the column-forming mitochondria in building a rather incomplete mitochondrial reticulum of the masseter muscle. Subsarcolemmal nuclei presented nuclear envelope-associated RyRs. Moreover, t-tubules were contacting the nuclear envelope and they were seemingly filled from the perinuclear space. This could suggest that nucleoplasmic calcium could contribute to balance the cytosolic concentration via pre-built anatomical routes: (i) indirectly, via the RyRs of the nuclear envelope and (ii) directly via the communication of t-tubules and sarcoplasmic reticulum through the perinuclear space.
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Affiliation(s)
- M C Rusu
- Division of Anatomy, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
| | - M I Nicolescu
- Division of Histology, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; "Victor Babeș" National Institute of Pathology, Bucharest, Romania
| | - A M Jianu
- Division of Anatomy, Faculty of Medicine, "Victor Babeş" University of Medicine and Pharmacy, Timişoara, Romania
| | - V S Mănoiu
- Department of Cellular and Molecular Biology, National Institute of Research and Development for Biological Sciences, Bucharest, Romania
| | - A C Ilie
- Division of Anatomy, Faculty of Medicine, "Victor Babeş" University of Medicine and Pharmacy, Timişoara, Romania
| | - D Dincă
- Department II of Surgical Clinical Divisions, Faculty of Medicine, "Ovidius" University, Constanţa, Romania
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Poole DC. Edward F. Adolph Distinguished Lecture. Contemporary model of muscle microcirculation: gateway to function and dysfunction. J Appl Physiol (1985) 2019; 127:1012-1033. [PMID: 31095460 DOI: 10.1152/japplphysiol.00013.2019] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This review strikes at the very heart of how the microcirculation functions to facilitate blood-tissue oxygen, substrate, and metabolite fluxes in skeletal muscle. Contemporary evidence, marshalled from animals and humans using the latest techniques, challenges iconic perspectives that have changed little over the past century. Those perspectives include the following: the presence of contractile or collapsible capillaries in muscle, unitary control by precapillary sphincters, capillary recruitment at the onset of contractions, and the notion of capillary-to-mitochondrial diffusion distances as limiting O2 delivery. Today a wealth of physiological, morphological, and intravital microscopy evidence presents a completely different picture of microcirculatory control. Specifically, capillary red blood cell (RBC) and plasma flux is controlled primarily at the arteriolar level with most capillaries, in healthy muscle, supporting at least some flow at rest. In healthy skeletal muscle, this permits substrate access (whether carried in RBCs or plasma) to a prodigious total capillary surface area. Pathologies such as heart failure or diabetes decrease access to that exchange surface by reducing the proportion of flowing capillaries at rest and during exercise. Capillary morphology and function vary disparately among tissues. The contemporary model of capillary function explains how, following the onset of exercise, muscle O2 uptake kinetics can be extremely fast in health but slowed in heart failure and diabetes impairing contractile function and exercise tolerance. It is argued that adoption of this model is fundamental for understanding microvascular function and dysfunction and, as such, to the design and evaluation of effective therapeutic strategies to improve exercise tolerance and decrease morbidity and mortality in disease.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology, Anatomy and Physiology, Kansas State University, Manhattan, Kansas
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40
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Faitg J, Leduc-Gaudet JP, Reynaud O, Ferland G, Gaudreau P, Gouspillou G. Effects of Aging and Caloric Restriction on Fiber Type Composition, Mitochondrial Morphology and Dynamics in Rat Oxidative and Glycolytic Muscles. Front Physiol 2019; 10:420. [PMID: 31114501 PMCID: PMC6503296 DOI: 10.3389/fphys.2019.00420] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 03/27/2019] [Indexed: 12/22/2022] Open
Abstract
Aging is associated with a progressive decline in muscle mass and strength, a process known as sarcopenia. Evidence indicates that mitochondrial dysfunction plays a causal role in sarcopenia and suggests that alterations in mitochondrial dynamics/morphology may represent an underlying mechanism. Caloric restriction (CR) is among the most efficient nonpharmacological interventions to attenuate sarcopenia in rodents and is thought to exert its beneficial effects by improving mitochondrial function. However, CR effects on mitochondrial morphology and dynamics, especially in aging muscle, remain unknown. To address this issue, we investigated mitochondrial morphology and dynamics in the oxidative soleus (SOL) and glycolytic white gastrocnemius (WG) muscles of adult (9-month-old) ad libitum-fed (AL; A-AL), old (22-month-old) AL-fed (O-AL), and old CR (O-CR) rats. We show that CR attenuates the aging-related decline in the muscle-to-body-weight ratio, a sarcopenic index. CR also prevented the effects of aging on muscle fiber type composition in both muscles. With aging, the SOL displayed fragmented SubSarcolemmal (SS) and InterMyoFibrillar (IMF) mitochondria, an effect attenuated by CR. Aged WG displayed enlarged SS and more complex/branched IMF mitochondria. CR had marginal anti-aging effects on WG mitochondrial morphology. In the SOL, DRP1 (pro-fission protein) content was higher in O-AL vs YA-AL, and Mfn2 (pro-fusion) content was higher in O-CR vs A-AL. In the gastrocnemius, Mfn2, Drp1, and Fis1 (pro-fission) contents were higher in O-AL vs A-AL. CR reduced this aging-related increase in Mfn2 and Fis1 content. Overall, these results reveal for the first time that aging differentially impacts mitochondrial morphology and dynamics in different muscle fiber types, by increasing fission/fragmentation in oxidative fibers while enhancing mitochondrial size and branching in glycolytic fibers. Our results also indicate that although CR partially attenuates aging-related changes in mitochondrial dynamics in glycolytic fibers, its anti-aging effect on mitochondrial morphology is restricted to oxidative fibers.
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Affiliation(s)
- Julie Faitg
- Département de Biologie, Faculté des Sciences, UQAM, Montreal, QC, Canada.,Groupe de recherche en Activité Physique Adaptée, Montreal, QC, Canada
| | - Jean-Philippe Leduc-Gaudet
- Groupe de recherche en Activité Physique Adaptée, Montreal, QC, Canada.,Meakins-Christie Laboratories, Department of Medicine and Division of Experimental Medicine, McGill University, Montreal, QC, Canada.,Département des sciences de l'activité physique, Faculté des Sciences, UQAM, Montreal, QC, Canada
| | - Olivier Reynaud
- Groupe de recherche en Activité Physique Adaptée, Montreal, QC, Canada.,Département des sciences de l'activité physique, Faculté des Sciences, UQAM, Montreal, QC, Canada
| | - Guylaine Ferland
- Institut de cardiologie de Montréal Research Center, Montreal, QC, Canada.,Department of Nutrition, University of Montreal, Montreal, QC, Canada
| | - Pierrette Gaudreau
- Laboratory of Neuroendocrinology of Aging, Centre Hospitalier de l'Université de Montréal Research Center (CRCHUM), Montreal, QC, Canada.,Department of Medicine,University of Montreal, Montreal, QC, Canada
| | - Gilles Gouspillou
- Groupe de recherche en Activité Physique Adaptée, Montreal, QC, Canada.,Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal, Montreal, QC, Canada
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41
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Holash RJ, MacIntosh BR. A stochastic simulation of skeletal muscle calcium transients in a structurally realistic sarcomere model using MCell. PLoS Comput Biol 2019; 15:e1006712. [PMID: 30845143 PMCID: PMC6424466 DOI: 10.1371/journal.pcbi.1006712] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 03/19/2019] [Accepted: 12/11/2018] [Indexed: 11/18/2022] Open
Abstract
Skeletal muscle contraction is initiated when an action potential triggers the release of Ca2+ into the sarcomere in a process referred to as excitation-contraction coupling. The speed and scale of this process makes direct observation very challenging and invasive. To determine how the concentration of Ca2+ changes within the myofibril during a single activation, several simulation models have been developed. These models follow a common pattern; divide the half sarcomere into a series of compartments, then use ordinary differential equations to solve reactions occurring within and between the compartments. To further develop this type of simulation, we have created a realistic structural model of a skeletal muscle myofibrillar half-sarcomere using MCell software that incorporates the myofilament lattice structure. Using this simulation model, we were successful in reproducing the averaged calcium transient during a single activation consistent with both the experimental and previous simulation results. In addition, our simulation demonstrated that the inclusion of the myofilament lattice within our model produced an asymmetric distribution of Ca2+, with more Ca2+ accumulating near the Z-disk and less Ca2+ reaching the m-line. This asymmetric distribution of Ca2+ is also apparent when we examine how the Ca2+ are bound to the troponin-C proteins along the actin filaments. Our simulation model also allowed us to produce advanced visualizations of this process, including two simulation animations, allowing us to view Ca2+ release, diffusion, binding and uptake within the myofibrillar half-sarcomere.
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Affiliation(s)
- Robert John Holash
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
| | - Brian R. MacIntosh
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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42
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Vincent AE, White K, Davey T, Philips J, Ogden RT, Lawless C, Warren C, Hall MG, Ng YS, Falkous G, Holden T, Deehan D, Taylor RW, Turnbull DM, Picard M. Quantitative 3D Mapping of the Human Skeletal Muscle Mitochondrial Network. Cell Rep 2019; 26:996-1009.e4. [PMID: 30655224 PMCID: PMC6513570 DOI: 10.1016/j.celrep.2019.01.010] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 10/11/2018] [Accepted: 01/02/2019] [Indexed: 01/07/2023] Open
Abstract
Genetic and biochemical defects of mitochondrial function are a major
cause of human disease, but their link to mitochondrial morphology in
situ has not been defined. Here, we develop a quantitative
three-dimensional approach to map mitochondrial network organization in human
muscle at electron microscopy resolution. We establish morphological differences
between human and mouse and among patients with mitochondrial DNA (mtDNA)
diseases compared to healthy controls. We also define the ultrastructure and
prevalence of mitochondrial nanotunnels, which exist as either free-ended or
connecting membrane protrusions across non-adjacent mitochondria. A multivariate
model integrating mitochondrial volume, morphological complexity, and branching
anisotropy computed across individual mitochondria and mitochondrial populations
identifies increased proportion of simple mitochondria and nanotunnels as a
discriminant signature of mitochondrial stress. Overall, these data define the
nature of the mitochondrial network in human muscle, quantify human-mouse
differences, and suggest potential morphological markers of mitochondrial
dysfunction in human tissues. Vincent et al. use 3D electron microscopy to provide a quantitative
morphometric assessment of human skeletal muscle mitochondria. They find that
healthy human muscle mitochondria differ from mouse mitochondria and show that
primary mtDNA defects are associated with a distinct morphological signature
including increased abundance of mitochondrial nanotunnels.
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Affiliation(s)
- Amy E Vincent
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK; MRC Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK
| | - Kathryn White
- EM Research Services, Newcastle University, Newcastle upon Tyne, UK
| | - Tracey Davey
- EM Research Services, Newcastle University, Newcastle upon Tyne, UK
| | - Jonathan Philips
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - R Todd Ogden
- Institute of Child Health, University College London, London, UK
| | - Conor Lawless
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Charlotte Warren
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK; MRC Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK
| | - Matt G Hall
- National Physical Laboratory, Teddington, UK; Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Yi Shiau Ng
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Gavin Falkous
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Thomas Holden
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - David Deehan
- Department of Biostatistics, Columbia University Mailman School of Public Health, New York, NY, USA
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Doug M Turnbull
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK; MRC Centre for Ageing and Vitality, Newcastle University, Newcastle upon Tyne, UK.
| | - Martin Picard
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY, USA; Department of Neurology and Columbia Translational Neuroscience Initiative, H. Houston Merritt Center, Columbia University Irving Medical Center, New York, NY, USA; Columbia University Aging Center, Columbia University, New York, NY, USA.
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43
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Lynch JM, Dolman AJ, Guo C, Dolan K, Xiang C, Reda S, Li B, Prasanna G. Mutant myocilin impacts sarcomere ultrastructure in mouse gastrocnemius muscle. PLoS One 2018; 13:e0206801. [PMID: 30395621 PMCID: PMC6218065 DOI: 10.1371/journal.pone.0206801] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 10/19/2018] [Indexed: 11/19/2022] Open
Abstract
Myocilin (MYOC) is the gene with mutations most common in glaucoma. In the eye, MYOC is in trabecular meshwork, ciliary body, and retina. Other tissues with high MYOC transcript levels are skeletal muscle and heart. To date, the function of wild-type MYOC remains unknown and how mutant MYOC causes high intraocular pressure and glaucoma is ambiguous. By investigating mutant MYOC in a non-ocular tissue we hoped to obtain novel insight into mutant MYOC pathology. For this study, we utilized a transgenic mouse expressing human mutant MYOC Y437H protein and we examined its skeletal (gastrocnemius) muscle phenotype. Electron micrographs showed that sarcomeres in the skeletal muscle of mutant CMV-MYOC-Y437H mice had multiple M-bands. Western blots of soluble muscle lysates from transgenics indicated a decrease in two M-band proteins, myomesin 1 (MYOM1) and muscle creatine kinase (CKM). Immunoprecipitation identified CKM as a MYOC binding partner. Our results suggest that binding of mutant MYOC to CKM is changing sarcomere ultrastructure and this may adversely impact muscle function. We speculate that a person carrying the mutant MYOC mutation will likely have a glaucoma phenotype and may also have undiagnosed muscle ailments or vice versa, both of which will have to be monitored and treated.
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MESH Headings
- Animals
- Cytoskeletal Proteins/genetics
- Cytoskeletal Proteins/metabolism
- Disease Models, Animal
- Eye Proteins/genetics
- Eye Proteins/metabolism
- Female
- Gene Expression
- Glaucoma, Open-Angle/genetics
- Glaucoma, Open-Angle/metabolism
- Glaucoma, Open-Angle/pathology
- Glycoproteins/genetics
- Glycoproteins/metabolism
- Humans
- Intraocular Pressure/genetics
- Male
- Mice
- Mice, Mutant Strains
- Mice, Transgenic
- Microscopy, Electron, Transmission
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/ultrastructure
- Mutant Proteins/genetics
- Mutant Proteins/metabolism
- Mutation
- Myocardium/metabolism
- Phenotype
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Sarcomeres/genetics
- Sarcomeres/metabolism
- Sarcomeres/ultrastructure
- Trabecular Meshwork/metabolism
- Trabecular Meshwork/ultrastructure
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Affiliation(s)
- Jeffrey M. Lynch
- Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
- * E-mail:
| | - Andrew J. Dolman
- Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Chenying Guo
- Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Katie Dolan
- Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Chuanxi Xiang
- Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Samir Reda
- Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Bing Li
- Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Ganesh Prasanna
- Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
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44
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Hood DA, Memme JM, Oliveira AN, Triolo M. Maintenance of Skeletal Muscle Mitochondria in Health, Exercise, and Aging. Annu Rev Physiol 2018; 81:19-41. [PMID: 30216742 DOI: 10.1146/annurev-physiol-020518-114310] [Citation(s) in RCA: 267] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondria are critical organelles responsible for regulating the metabolic status of skeletal muscle. These organelles exhibit remarkable plasticity by adapting their volume, structure, and function in response to chronic exercise, disuse, aging, and disease. A single bout of exercise initiates signaling to provoke increases in mitochondrial biogenesis, balanced by the onset of organelle turnover carried out by the mitophagy pathway. This accelerated turnover ensures the presence of a high functioning network of mitochondria designed for optimal ATP supply, with the consequence of favoring lipid metabolism, maintaining muscle mass, and reducing apoptotic susceptibility over the longer term. Conversely, aging and disuse are associated with reductions in muscle mass that are in part attributable to dysregulation of the mitochondrial network and impaired mitochondrial function. Therefore, exercise represents a viable, nonpharmaceutical therapy with the potential to reverse and enhance the impaired mitochondrial function observed with aging and chronic muscle disuse.
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Affiliation(s)
- David A Hood
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, M3J 1P3, Canada;
| | - Jonathan M Memme
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, M3J 1P3, Canada;
| | - Ashley N Oliveira
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, M3J 1P3, Canada;
| | - Matthew Triolo
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, M3J 1P3, Canada;
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45
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Perry CGR, Hawley JA. Molecular Basis of Exercise-Induced Skeletal Muscle Mitochondrial Biogenesis: Historical Advances, Current Knowledge, and Future Challenges. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a029686. [PMID: 28507194 DOI: 10.1101/cshperspect.a029686] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We provide an overview of groundbreaking studies that laid the foundation for our current understanding of exercise-induced mitochondrial biogenesis and its contribution to human skeletal muscle fitness. We highlight the mechanisms by which skeletal muscle responds to the acute perturbations in cellular energy homeostasis evoked by a single bout of endurance-based exercise and the adaptations resulting from the repeated demands of exercise training that ultimately promote mitochondrial biogenesis through hormetic feedback loops. Despite intense research efforts to elucidate the cellular mechanisms underpinning mitochondrial biogenesis in skeletal muscle, translating this basic knowledge into improved metabolic health at the population level remains a future challenge.
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Affiliation(s)
- Christopher G R Perry
- School of Kinesiology and Health Science, Muscle Health Research Centre, York University, Toronto, Ontario M3J 1P3, Canada
| | - John A Hawley
- Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne 3000, Australia.,Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Merseyside L3 5UA, United Kingdom
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46
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Silver J, Wadley G, Lamon S. Mitochondrial regulation in skeletal muscle: A role for non‐coding RNAs? Exp Physiol 2018; 103:1132-1144. [PMID: 29885080 DOI: 10.1113/ep086846] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 05/30/2018] [Indexed: 12/12/2022]
Affiliation(s)
- Jessica Silver
- Institute for Physical Activity and Nutrition (IPAN) Deakin University Geelong Victoria Australia
| | - Glenn Wadley
- Institute for Physical Activity and Nutrition (IPAN) Deakin University Geelong Victoria Australia
| | - Séverine Lamon
- Institute for Physical Activity and Nutrition (IPAN) Deakin University Geelong Victoria Australia
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47
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Koga D, Kusumi S, Watanabe T. Backscattered electron imaging of resin-embedded sections. Microscopy (Oxf) 2018; 67:5038522. [PMID: 29920601 DOI: 10.1093/jmicro/dfy028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 05/23/2018] [Indexed: 02/28/2024] Open
Abstract
Scanning electron microscopes have longer focal depths than transmission electron microscopes and enable visualization of the three-dimensional (3D) surface structures of specimens. While scanning electron microscopy (SEM) in biological research was generally used for the analysis of bulk specimens until around the year 2000, more recent instrumental advances have broadened the application of SEM; for example, backscattered electron (BSE) signals under low accelerating voltages allow block-face and section-face images of tissues embedded in resin to be acquired. This technical breakthrough has led to the development of novel 3D imaging techniques including focused ion beam SEM, serial-block face SEM and serial section SEM. Using these new techniques, the 3D shapes of cells and cell organelles have been revealed clearly through reconstruction of serial tomographic images. In this review, we address two modern SEM techniques: section-face imaging of resin-embedded tissue samples based on BSE observations, and serial section SEM for reconstruction of the 3D structures of cells and organelles from BSE-mode SEM images of consecutive ultrathin sections on solid substrates.
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Affiliation(s)
- Daisuke Koga
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
| | - Satoshi Kusumi
- Division of Morphological Sciences, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Tsuyoshi Watanabe
- Department of Microscopic Anatomy and Cell Biology, Asahikawa Medical University, Asahikawa, Japan
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48
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Reis MM, Van Beers R, Al-Sarayreh M, Shorten P, Yan WQ, Saeys W, Klette R, Craigie C. Chemometrics and hyperspectral imaging applied to assessment of chemical, textural and structural characteristics of meat. Meat Sci 2018; 144:100-109. [PMID: 29960721 DOI: 10.1016/j.meatsci.2018.05.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 05/28/2018] [Accepted: 05/28/2018] [Indexed: 01/13/2023]
Abstract
Spectroscopy in the visible near-infrared spectral (Vis-NIRS) range combined with imaging techniques (hyperspectral imaging, HSI) allows assessment of chemical composition, texture, and meat structure. The use of HSI in the meat and food industry has observed a significant growth in the last decade, yet its use for assessment of meat it is not optimal yet. The application of HSI for assessment of meat is reviewed with focus on its ability to capture meat unique chemical and structural characteristics. While HSI is widely used for assessment of chemical composition, a limited number of evidences on its ability to handle the effect of different sources of variation on the assessment is found. The use of spatially resolved spectroscopy has been able to detect structural information related to animal background, muscle type, rigor process and ageing. Similarly the use of texture features seem to capture unique characteristics of meat.
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Affiliation(s)
| | - Robbe Van Beers
- KU Leuven, Department of Biosystems, MeBioS, Leuven, Belgium
| | | | | | - Wei Qi Yan
- Auckland University of Technology, Auckland, New Zealand
| | - Wouter Saeys
- KU Leuven, Department of Biosystems, MeBioS, Leuven, Belgium
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49
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Huang L, Tepaamorndech S, Kirschke CP, Newman JW, Keyes WR, Pedersen TL, Dumnil J. Aberrant fatty acid metabolism in skeletal muscle contributes to insulin resistance in zinc transporter 7 ( znt7)-knockout mice. J Biol Chem 2018; 293:7549-7563. [PMID: 29555680 DOI: 10.1074/jbc.m117.817692] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 03/12/2018] [Indexed: 12/22/2022] Open
Abstract
ZnT7 (Slc30a7) is a widely expressed zinc transporter involved in sequestration of zinc into the Golgi apparatus and vesicular compartments. znt7-knockout (KO) mice are mildly zinc-deficient and lean. Despite their lean phenotype, adult male znt7-KO mice are prone to insulin resistance. We hypothesized that fat partitioning from adipose to nonadipose tissues causes insulin resistance in znt7-KO mice. Here, we used biological and biochemical methods, including fatty acid and oxylipin profiling, EM, immunohistochemistry, quantitative RT-PCR, and Western blot analysis, to identify the underlying mechanism of insulin resistance in znt7-KO mice. We found that insulin resistance in this model was primarily associated with increased intracellular fatty acid levels in the skeletal muscle, which promoted intracellular lipid accumulation and production of bioactive lipid mediators, such as 12,13-dihydroxyoctadecanoic acid (12,13-DiHOME) and 12-hydroxyeicosatetraenoic acid (12-HETE). The expression of fatty acid-binding protein 3 (Fabp3) was dramatically up-regulated in the znt7-KO muscle cells accompanied by increased expression of Cd36, Slc27a1, and Slc27a4, the three major fatty acid transporters in the skeletal muscle. We also demonstrated that znt7-KO muscle cells had increased fatty acid oxidative capacity, indicated by enlarged mitochondria and increased mRNA or protein expression of key enzymes involved in the fatty acid mitochondrial shuttle and β-oxidation. We conclude that increased fatty acid uptake in the znt7-KO skeletal muscle is a key factor that contributes to the excessive intracellular lipid deposit and elevated production of bioactive lipid mediators. These mediators may play pivotal roles in oxidative stress and inflammation, leading to insulin resistance.
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Affiliation(s)
- Liping Huang
- From the Obesity and Metabolism Research Unit, United States Department of Agriculture/Agricultural Research Service/Western Human Nutrition Research Center, Davis, California 95616, .,Department of Nutrition and.,Integrative Genetics and Genomics Graduate Group, University of California, Davis, California 95616, and
| | - Surapun Tepaamorndech
- Integrative Genetics and Genomics Graduate Group, University of California, Davis, California 95616, and.,Food Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Phahonyothin Road, Pathum Thani 12120, Thailand
| | - Catherine P Kirschke
- From the Obesity and Metabolism Research Unit, United States Department of Agriculture/Agricultural Research Service/Western Human Nutrition Research Center, Davis, California 95616
| | - John W Newman
- From the Obesity and Metabolism Research Unit, United States Department of Agriculture/Agricultural Research Service/Western Human Nutrition Research Center, Davis, California 95616.,Department of Nutrition and
| | - William R Keyes
- From the Obesity and Metabolism Research Unit, United States Department of Agriculture/Agricultural Research Service/Western Human Nutrition Research Center, Davis, California 95616
| | - Theresa L Pedersen
- From the Obesity and Metabolism Research Unit, United States Department of Agriculture/Agricultural Research Service/Western Human Nutrition Research Center, Davis, California 95616
| | - Jureeporn Dumnil
- Food Biotechnology Research Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Phahonyothin Road, Pathum Thani 12120, Thailand
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50
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Martinvalet D. The role of the mitochondria and the endoplasmic reticulum contact sites in the development of the immune responses. Cell Death Dis 2018; 9:336. [PMID: 29491398 PMCID: PMC5832423 DOI: 10.1038/s41419-017-0237-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 11/25/2017] [Accepted: 11/28/2017] [Indexed: 12/12/2022]
Abstract
Mitochondria and endoplasmic reticulum (ER) contact sites (MERCs) are dynamic modules enriched in subset of lipids and specialized proteins that determine their structure and functions. The MERCs regulate lipid transfer, autophagosome formation, mitochondrial fission, Ca2+ homeostasis and apoptosis. Since these functions are essential for cell biology, it is therefore not surprising that MERCs also play a critical role in organ physiology among which the immune system stands by its critical host defense function. This defense system must discriminate and tolerate host cells and beneficial commensal microorganisms while eliminating pathogenic ones in order to preserve normal homeostasis. To meet this goal, the immune system has two lines of defense. First, the fast acting but unspecific innate immune system relies on anatomical physical barriers and subsets of hematopoietically derived cells expressing germline-encoded receptors called pattern recognition receptors (PRR) recognizing conserved motifs on the pathogens. Second, the slower but very specific adaptive immune response is added to complement innate immunity. Adaptive immunity relies on another set of specialized cells, the lymphocytes, harboring receptors requiring somatic recombination to be expressed. Both innate and adaptive immune cells must be activated to phagocytose and process pathogens, migrate, proliferate, release soluble factors and destroy infected cells. Some of these functions are strongly dependent on lipid transfer, autophagosome formation, mitochondrial fission, and Ca2+ flux; this indicates that MERCs could regulate immunity.
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Affiliation(s)
- Denis Martinvalet
- Department of Cell Physiology and Metabolism, Geneva Medical School, 1211, Geneva, Switzerland.
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