1
|
Benaroya H. Mitochondria and MICOS - function and modeling. Rev Neurosci 2024; 35:503-531. [PMID: 38369708 DOI: 10.1515/revneuro-2024-0004] [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: 01/10/2024] [Accepted: 01/14/2024] [Indexed: 02/20/2024]
Abstract
An extensive review is presented on mitochondrial structure and function, mitochondrial proteins, the outer and inner membranes, cristae, the role of F1FO-ATP synthase, the mitochondrial contact site and cristae organizing system (MICOS), the sorting and assembly machinery morphology and function, and phospholipids, in particular cardiolipin. Aspects of mitochondrial regulation under physiological and pathological conditions are outlined, in particular the role of dysregulated MICOS protein subunit Mic60 in Parkinson's disease, the relations between mitochondrial quality control and proteins, and mitochondria as signaling organelles. A mathematical modeling approach of cristae and MICOS using mechanical beam theory is introduced and outlined. The proposed modeling is based on the premise that an optimization framework can be used for a better understanding of critical mitochondrial function and also to better map certain experiments and clinical interventions.
Collapse
Affiliation(s)
- Haym Benaroya
- Department of Mechanical and Aerospace Engineering, Rutgers University, 98 Brett Road, Piscataway, NJ 08854, USA
| |
Collapse
|
2
|
Hinton A, Claypool SM, Neikirk K, Senoo N, Wanjalla CN, Kirabo A, Williams CR. Mitochondrial Structure and Function in Human Heart Failure. Circ Res 2024; 135:372-396. [PMID: 38963864 PMCID: PMC11225798 DOI: 10.1161/circresaha.124.323800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/06/2024]
Abstract
Despite clinical and scientific advancements, heart failure is the major cause of morbidity and mortality worldwide. Both mitochondrial dysfunction and inflammation contribute to the development and progression of heart failure. Although inflammation is crucial to reparative healing following acute cardiomyocyte injury, chronic inflammation damages the heart, impairs function, and decreases cardiac output. Mitochondria, which comprise one third of cardiomyocyte volume, may prove a potential therapeutic target for heart failure. Known primarily for energy production, mitochondria are also involved in other processes including calcium homeostasis and the regulation of cellular apoptosis. Mitochondrial function is closely related to morphology, which alters through mitochondrial dynamics, thus ensuring that the energy needs of the cell are met. However, in heart failure, changes in substrate use lead to mitochondrial dysfunction and impaired myocyte function. This review discusses mitochondrial and cristae dynamics, including the role of the mitochondria contact site and cristae organizing system complex in mitochondrial ultrastructure changes. Additionally, this review covers the role of mitochondria-endoplasmic reticulum contact sites, mitochondrial communication via nanotunnels, and altered metabolite production during heart failure. We highlight these often-neglected factors and promising clinical mitochondrial targets for heart failure.
Collapse
Affiliation(s)
- Antentor Hinton
- Department of Molecular Physiology and Biophysics (A.H., K.N.), Vanderbilt University Medical Center, Nashville
| | - Steven M. Claypool
- Department of Physiology, Mitochondrial Phospholipid Research Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (S.M.C., N.S.)
| | - Kit Neikirk
- Department of Molecular Physiology and Biophysics (A.H., K.N.), Vanderbilt University Medical Center, Nashville
| | - Nanami Senoo
- Department of Physiology, Mitochondrial Phospholipid Research Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (S.M.C., N.S.)
| | - Celestine N. Wanjalla
- Department of Medicine, Division of Clinical Pharmacology (C.N.W., A.K.), Vanderbilt University Medical Center, Nashville
| | - Annet Kirabo
- Department of Medicine, Division of Clinical Pharmacology (C.N.W., A.K.), Vanderbilt University Medical Center, Nashville
- Vanderbilt Center for Immunobiology (A.K.)
- Vanderbilt Institute for Infection, Immunology and Inflammation (A.K.)
- Vanderbilt Institute for Global Health (A.K.)
| | - Clintoria R. Williams
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH (C.R.W.)
| |
Collapse
|
3
|
Erozan A, Lösel PD, Heuveline V, Weinhardt V. Automated 3D cytoplasm segmentation in soft X-ray tomography. iScience 2024; 27:109856. [PMID: 38784019 PMCID: PMC11112332 DOI: 10.1016/j.isci.2024.109856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/22/2024] [Accepted: 04/27/2024] [Indexed: 05/25/2024] Open
Abstract
Cells' structure is key to understanding cellular function, diagnostics, and therapy development. Soft X-ray tomography (SXT) is a unique tool to image cellular structure without fixation or labeling at high spatial resolution and throughput. Fast acquisition times increase demand for accelerated image analysis, like segmentation. Currently, segmenting cellular structures is done manually and is a major bottleneck in the SXT data analysis. This paper introduces ACSeg, an automated 3D cytoplasm segmentation model. ACSeg is generated using semi-automated labels and 3D U-Net and is trained on 43 SXT tomograms of immune T cells, rapidly converging to high-accuracy segmentation, therefore reducing time and labor. Furthermore, adding only 6 SXT tomograms of other cell types diversifies the model, showing potential for optimal experimental design. ACSeg successfully segmented unseen tomograms and is published on Biomedisa, enabling high-throughput analysis of cell volume and structure of cytoplasm in diverse cell types.
Collapse
Affiliation(s)
- Ayse Erozan
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
- Engineering Mathematics and Computing Lab, Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
- Data Mining and Uncertainty Quantification, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Philipp D. Lösel
- Engineering Mathematics and Computing Lab, Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
- Data Mining and Uncertainty Quantification, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
- Department of Materials Physics Research School of Physics, The Australian National University, Acton ACT, Australia
| | - Vincent Heuveline
- Engineering Mathematics and Computing Lab, Interdisciplinary Center for Scientific Computing, Heidelberg University, Heidelberg, Germany
- Data Mining and Uncertainty Quantification, Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Venera Weinhardt
- Centre for Organismal Studies, Heidelberg University, Heidelberg, Germany
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| |
Collapse
|
4
|
Wu K, Shieh JS, Qin L, Guo JJ. Mitochondrial mechanisms in the pathogenesis of chronic inflammatory musculoskeletal disorders. Cell Biosci 2024; 14:76. [PMID: 38849951 PMCID: PMC11162051 DOI: 10.1186/s13578-024-01259-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Accepted: 05/29/2024] [Indexed: 06/09/2024] Open
Abstract
Chronic inflammatory musculoskeletal disorders characterized by prolonged muscle inflammation, resulting in enduring pain and diminished functionality, pose significant challenges for the patients. Emerging scientific evidence points to mitochondrial malfunction as a pivotal factor contributing to these ailments. Mitochondria play a critical role in powering skeletal muscle activity, but in the context of persistent inflammation, disruptions in their quantity, configuration, and performance have been well-documented. Various disturbances, encompassing alterations in mitochondrial dynamics (such as fission and fusion), calcium regulation, oxidative stress, biogenesis, and the process of mitophagy, are believed to play a central role in the progression of these disorders. Additionally, unfolded protein responses and the accumulation of fatty acids within muscle cells may adversely affect the internal milieu, impairing the equilibrium of mitochondrial functioning. The structural discrepancies between different mitochondrial subsets namely, intramyofibrillar and subsarcolemmal mitochondria likely impact their metabolic capabilities and susceptibility to inflammatory influences. The release of signals from damaged mitochondria is known to incite inflammatory responses. Intriguingly, migrasomes and extracellular vesicles serve as vehicles for intercellular transfer of mitochondria, aiding in the removal of impaired mitochondria and regulation of inflammation. Viral infections have been implicated in inducing stress on mitochondria. Prolonged dysfunction of these vital organelles sustains oxidative harm, metabolic irregularities, and heightened cytokine release, impeding the body's ability to repair tissues. This review provides a comprehensive analysis of advancements in understanding changes in the intracellular environment, mitochondrial architecture and distribution, biogenesis, dynamics, autophagy, oxidative stress, cytokines associated with mitochondria, vesicular structures, and associated membranes in the context of chronic inflammatory musculoskeletal disorders. Strategies targeting key elements regulating mitochondrial quality exhibit promise in the restoration of mitochondrial function, alleviation of inflammation, and enhancement of overall outcomes.
Collapse
Affiliation(s)
- Kailun Wu
- Department of Orthopedics, The Fourth Affiliated Hospital of Soochow University/Suzhou Dushu Lake Hospital, Suzhou, Jiangsu, People's Republic of China
- Department of Orthopedics and Sports Medicine, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, People's Republic of China
| | - Ju-Sheng Shieh
- Department of Periodontology, School of Dentistry, Tri-Service General Hospital, National Defense Medical Center, Taipei City, 11490, Taiwan
| | - Ling Qin
- Musculoskeletal Research Laboratory of the Department of Orthopaedics & Traumatology, The Chinese University of Hong Kong, Hong Kong, SAR, People's Republic of China
| | - Jiong Jiong Guo
- Department of Orthopedics and Sports Medicine, The First Affiliated Hospital of Soochow University, 188 Shizi Street, Suzhou, 215006, People's Republic of China.
- MOE China-Europe Sports Medicine Belt and Road Joint Laboratory, Soochow University, Suzhou, Jiangsu, People's Republic of China.
| |
Collapse
|
5
|
Zhou L, Su W, Wang Y, Zhang Y, Xia Z, Lei S. FOXO1 reduces STAT3 activation and causes impaired mitochondrial quality control in diabetic cardiomyopathy. Diabetes Obes Metab 2024; 26:732-744. [PMID: 37961034 DOI: 10.1111/dom.15369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023]
Abstract
AIMS To investigate the role of FOXO1 in STAT3 activation and mitochondrial quality control in the diabetic heart. METHODS Type 1 diabetes mellitus (T1DM) was induced in rats by a single intraperitoneal injection of 60 mg · kg-1 streptozotocin (STZ), while type 2 diabetes mellitus (T2DM) was induced in rats with a high-fat diet through intraperitoneal injection of 35 mg · kg-1 STZ. Primary neonatal mouse cardiomyocytes and H9c2 cells were exposed to low glucose (5.5 mM) or high glucose (HG; 30 mM) with or without treatment with the FOXO1 inhibitor AS1842856 (1 μM) for 24 hours. In addition, the diabetic db/db mice (aged 8 weeks) and sex- and age-matched non-diabetic db/+ mice were treated with vehicle or AS1842856 by oral gavage for 15 days at a dose of 5 mg · kg-1 · d-1 . RESULTS Rats with T1DM or T2DM had excessive cardiac FOXO1 activation, accompanied by decreased STAT3 activation. Immunofluorescence and immunoprecipitation analysis showed colocalization and association of FOXO1 and STAT3 under basal conditions in isolated cardiomyocytes. Selective inhibition of FOXO1 activation by AS1842856 or FOXO1 siRNA transfection improved STAT3 activation, mitophagy and mitochondrial fusion, and decreased mitochondrial fission in isolated cardiomyocytes exposed to HG. Transfection with STAT3 siRNA further reduced mitophagy, mitochondrial fusion and increased mitochondrial fission in HG-treated cardiomyocytes. AS1842856 alleviated cardiac dysfunction, pathological damage and improved STAT3 activation, mitophagy and mitochondrial dynamics in diabetic db/db mice. Additionally, AS1842856 improved mitochondrial function indicated by increased mitochondrial membrane potential and adenosine triphosphate production and decreased mitochondrial reactive oxygen species production in isolated cardiomyocytes exposed to HG. CONCLUSIONS Excessive FOXO1 activation during diabetes reduces STAT3 activation, with subsequent impairment of mitochondrial quality, ultimately promoting the development of diabetic cardiomyopathy.
Collapse
Affiliation(s)
- Lu Zhou
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Wating Su
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yafeng Wang
- Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuefu Zhang
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Zhongyuan Xia
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Shaoqing Lei
- Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, China
| |
Collapse
|
6
|
Khare H, Dongo Mendoza N, Zurzolo C. CellWalker: a user-friendly and modular computational pipeline for morphological analysis of microscopy images. Bioinformatics 2023; 39:btad710. [PMID: 38060265 PMCID: PMC10713108 DOI: 10.1093/bioinformatics/btad710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 11/07/2023] [Accepted: 12/06/2023] [Indexed: 12/08/2023] Open
Abstract
SUMMARY The implementation of computational tools for analysis of microscopy images has been one of the most important technological innovations in biology, providing researchers unmatched capabilities to comprehend cell shape and connectivity. While numerous tools exist for image annotation and segmentation, there is a noticeable gap when it comes to morphometric analysis of microscopy images. Most existing tools often measure features solely on 2D serial images, which can be difficult to extrapolate to 3D. For this reason, we introduce CellWalker, a computational toolbox that runs inside Blender, an open-source computer graphics software. This add-on improves the morphological analysis by seamlessly integrating analysis tools into the Blender workflow, providing visual feedback through a powerful 3D visualization, and leveraging the resources of Blender's community. CellWalker provides several morphometric analysis tools that can be used to calculate distances, volume, surface areas and to determine cross-sectional properties. It also includes tools to build skeletons, calculate distributions of subcellular organelles. In addition, this python-based tool contains 'visible-source' IPython notebooks accessories for segmentation of 2D/3D microscopy images using deep learning and visualization of the segmented images that are required as input to CellWalker. Overall, CellWalker provides practical tools for segmentation and morphological analysis of microscopy images in the form of an open-source and modular pipeline which allows a complete access to fine-tuning of algorithms through visible-source code while still retaining a result-oriented interface. AVAILABILITY AND IMPLEMENTATION CellWalker source code is available on GitHub (https://github.com/utraf-pasteur-institute/Cellwalker-blender and https://github.com/utraf-pasteur-institute/Cellwalker-notebooks) under a GPL-3 license.
Collapse
Affiliation(s)
- Harshavardhan Khare
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and Infection, CNRS UMR 3691, Université de Paris, Institut Pasteur, Paris, 75015, France
| | - Nathaly Dongo Mendoza
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and Infection, CNRS UMR 3691, Université de Paris, Institut Pasteur, Paris, 75015, France
- Centro de Investigación en Bioingeniería – BIO, Universidad de Ingeniería y Tecnología – UTEC, Lima, 15063, Perú
| | - Chiara Zurzolo
- Membrane Traffic and Pathogenesis Unit, Department of Cell Biology and Infection, CNRS UMR 3691, Université de Paris, Institut Pasteur, Paris, 75015, France
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, 80131, Italy
| |
Collapse
|
7
|
Ng EL, Reed AL, O'Connell CB, Alder NN. Using Live Cell STED Imaging to Visualize Mitochondrial Inner Membrane Ultrastructure in Neuronal Cell Models. J Vis Exp 2023:10.3791/65561. [PMID: 37458423 PMCID: PMC11067429 DOI: 10.3791/65561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/20/2023] Open
Abstract
Mitochondria play many essential roles in the cell, including energy production, regulation of Ca2+ homeostasis, lipid biosynthesis, and production of reactive oxygen species (ROS). These mitochondria-mediated processes take on specialized roles in neurons, coordinating aerobic metabolism to meet the high energy demands of these cells, modulating Ca2+ signaling, providing lipids for axon growth and regeneration, and tuning ROS production for neuronal development and function. Mitochondrial dysfunction is therefore a central driver in neurodegenerative diseases. Mitochondrial structure and function are inextricably linked. The morphologically complex inner membrane with structural infolds called cristae harbors many molecular systems that perform the signature processes of the mitochondrion. The architectural features of the inner membrane are ultrastructural and therefore, too small to be visualized by traditional diffraction-limited resolved microscopy. Thus, most insights on mitochondrial ultrastructure have come from electron microscopy on fixed samples. However, emerging technologies in super-resolution fluorescence microscopy now provide resolution down to tens of nanometers, allowing visualization of ultrastructural features in live cells. Super-resolution imaging therefore offers an unprecedented ability to directly image fine details of mitochondrial structure, nanoscale protein distributions, and cristae dynamics, providing fundamental new insights that link mitochondria to human health and disease. This protocol presents the use of stimulated emission depletion (STED) super-resolution microscopy to visualize the mitochondrial ultrastructure of live human neuroblastoma cells and primary rat neurons. This procedure is organized into five sections: (1) growth and differentiation of the SH-SY5Y cell line, (2) isolation, plating, and growth of primary rat hippocampal neurons, (3) procedures for staining cells for live STED imaging, (4) procedures for live cell STED experiments using a STED microscope for reference, and (5) guidance for segmentation and image processing using examples to measure and quantify morphological features of the inner membrane.
Collapse
Affiliation(s)
- Emery L Ng
- Center for Open Research Resources and Equipment, University of Connecticut
| | - Ashley L Reed
- Department of Molecular and Cell Biology, University of Connecticut
| | | | - Nathan N Alder
- Department of Molecular and Cell Biology, University of Connecticut;
| |
Collapse
|
8
|
Structural functionality of skeletal muscle mitochondria and its correlation with metabolic diseases. Clin Sci (Lond) 2022; 136:1851-1871. [PMID: 36545931 DOI: 10.1042/cs20220636] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022]
Abstract
The skeletal muscle is one of the largest organs in the mammalian body. Its remarkable ability to swiftly shift its substrate selection allows other organs like the brain to choose their preferred substrate first. Healthy skeletal muscle has a high level of metabolic flexibility, which is reduced in several metabolic diseases, including obesity and Type 2 diabetes (T2D). Skeletal muscle health is highly dependent on optimally functioning mitochondria that exist in a highly integrated network with the sarcoplasmic reticulum and sarcolemma. The three major mitochondrial processes: biogenesis, dynamics, and mitophagy, taken together, determine the quality of the mitochondrial network in the muscle. Since muscle health is primarily dependent on mitochondrial status, the mitochondrial processes are very tightly regulated in the skeletal muscle via transcription factors like peroxisome proliferator-activated receptor-γ coactivator-1α, peroxisome proliferator-activated receptors, estrogen-related receptors, nuclear respiratory factor, and Transcription factor A, mitochondrial. Physiological stimuli that enhance muscle energy expenditure, like cold and exercise, also promote a healthy mitochondrial phenotype and muscle health. In contrast, conditions like metabolic disorders, muscle dystrophies, and aging impair the mitochondrial phenotype, which is associated with poor muscle health. Further, exercise training is known to improve muscle health in aged individuals or during the early stages of metabolic disorders. This might suggest that conditions enhancing mitochondrial health can promote muscle health. Therefore, in this review, we take a critical overview of current knowledge about skeletal muscle mitochondria and the regulation of their quality. Also, we have discussed the molecular derailments that happen during various pathophysiological conditions and whether it is an effect or a cause.
Collapse
|
9
|
Benaroya H. Understanding mitochondria and the utility of optimization as a canonical framework for identifying and modeling mitochondrial pathways. Rev Neurosci 2022; 33:657-690. [PMID: 35219282 DOI: 10.1515/revneuro-2021-0138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/25/2022] [Indexed: 11/15/2022]
Abstract
The goal of this paper is to provide an overview of our current understanding of mitochondrial function as a framework to motivate the hypothesis that mitochondrial behavior is governed by optimization principles that are constrained by the laws of the physical and biological sciences. Then, mathematical optimization tools can generally be useful to model some of these processes under reasonable assumptions and limitations. We are specifically interested in optimizations via variational methods, which are briefly summarized. Within such an optimization framework, we suggest that the numerous mechanical instigators of cell and intracellular functioning can be modeled utilizing some of the principles of mechanics that govern engineered systems, as well as by the frequently observed feedback and feedforward mechanisms that coordinate the multitude of processes within cells. These mechanical aspects would need to be coupled to governing biochemical rules. Of course, biological systems are significantly more complex than engineered systems, and require considerably more experimentation to ascertain and characterize parameters and subsequent behavior. That complexity requires well-defined limitations and assumptions for any derived models. Optimality is being motivated as a framework to help us understand how cellular decisions are made, especially those that transition between physiological behaviors and dysfunctions along pathophysiological pathways. We elaborate on our interpretation of optimality and cellular decision making within the body of this paper, as we revisit these ideas in the numerous different contexts of mitochondrial functions.
Collapse
Affiliation(s)
- Haym Benaroya
- Department of Mechanical and Aerospace Engineering, Rutgers University, 98 Brett Road, Piscataway, NJ 08901, USA
| |
Collapse
|
10
|
Loconte V, White KL. The use of soft X-ray tomography to explore mitochondrial structure and function. Mol Metab 2021; 57:101421. [PMID: 34942399 PMCID: PMC8829759 DOI: 10.1016/j.molmet.2021.101421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 11/22/2021] [Accepted: 12/15/2021] [Indexed: 11/25/2022] Open
Abstract
Background Mitochondria are cellular organelles responsible for energy production, and dysregulation of the mitochondrial network is associated with many disease states. To fully characterize the mitochondrial network's structure and function, a three-dimensional whole cell mapping technique is required. Scope of review This review highlights the use of soft X-ray tomography (SXT) as a relatively high-throughput approach to quantify mitochondrial structure and function under multiple cellular conditions. Major conclusions The use of SXT opens the door for mapping cellular rearrangements during critical processes such as insulin secretion, stem cell differentiation, or disease progression. SXT provides unique information such as biochemical compositions or molecular densities of organelles and allows for unbiased, label-free imaging of intact whole cells. Mapping mitochondria in the context of the near-native cellular environment will reveal more information regarding mitochondrial network functions within the cell. Soft X-ray tomography (SXT) generates 3D organelle maps of intact cells. 3D maps reveal the positions of mitochondria and their molecular densities. SXT can be used to quantify and compare organelle contacts between conditions. SXT is unbiased imaging that identifies the contents of subcellular neighborhoods. SXT provides an exciting path for exploring metabolic dysfunction.
Collapse
Affiliation(s)
- Valentina Loconte
- Department of Anatomy, School of Medicine, UCSF, San Francisco, California, CA 94143; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Kate L White
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Department of Chemistry, Bridge Institute, Michelson Center for Convergent Bioscience, University of Southern California, Los Angeles, CA 90089, USA.
| |
Collapse
|
11
|
Kan S, Duan M, Liu Y, Wang C, Xie J. Role of Mitochondria in Physiology of Chondrocytes and Diseases of Osteoarthritis and Rheumatoid Arthritis. Cartilage 2021; 13:1102S-1121S. [PMID: 34894777 PMCID: PMC8804744 DOI: 10.1177/19476035211063858] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
PURPOSE OF REVIEW Mitochondria are recognized to be one of the most important organelles in chondrocytes for their role in triphosphate (ATP) generation through aerobic phosphorylation. Mitochondria also participate in many intracellular processes involving modulating reactive oxygen species (ROS), responding to instantaneous hypoxia stress, regulating cytoplasmic transport of calcium ion, and directing mitophagy to maintain the homeostasis of individual chondrocytes. DESIGNS To summarize the specific role of mitochondria in chondrocytes, we screened related papers in PubMed database and the search strategy is ((mitochondria) AND (chondrocyte)) AND (English [Language]). The articles published in the past 5 years were included and 130 papers were studied. RESULTS In recent years, the integrity of mitochondrial structure has been regarded as a prerequisite for normal chondrocyte survival and defect in mitochondrial function has been found in cartilage-related diseases, such as osteoarthritis (OA) and rheumatoid arthritis (RA). However, the understanding of mitochondria in cartilage is still largely limited. The mechanism on how the changes in mitochondrial structure and function directly lead to the occurrence and development of cartilage-related diseases remains to be elusive. CONCLUSION This review aims to summarize the role of mitochondria in chondrocytes under the physiological and pathological changes from ATP generation, calcium homeostasis, redox regulation, mitophagy modulation, mitochondria biogenesis to immune response activation. The enhanced understanding of molecular mechanisms in mitochondria might offer some new cues for cartilage remodeling and pathological intervention.
Collapse
Affiliation(s)
- Shiyi Kan
- State Key Laboratory of Oral Diseases,
West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Mengmeng Duan
- State Key Laboratory of Oral Diseases,
West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yang Liu
- State Key Laboratory of Oral Diseases,
West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chunli Wang
- “111” Project Laboratory of
Biomechanics and Tissue Repair, Bioengineering College, Chongqing University,
Chongqing, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases,
West China Hospital of Stomatology, Sichuan University, Chengdu, China,“111” Project Laboratory of
Biomechanics and Tissue Repair, Bioengineering College, Chongqing University,
Chongqing, China,Lab of Bone & Joint Disease, State
Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan
University, Chengdu, China,Jing Xie, Lab of Bone & Joint Disease,
State Key Laboratory of Oral Diseases, West China Hospital of Stomatology,
Sichuan University, Chengdu 610064, Sichuan, China.
| |
Collapse
|
12
|
Juhl AD, Heegaard CW, Werner S, Schneider G, Krishnan K, Covey DF, Wüstner D. Quantitative imaging of membrane contact sites for sterol transfer between endo-lysosomes and mitochondria in living cells. Sci Rep 2021; 11:8927. [PMID: 33903617 PMCID: PMC8076251 DOI: 10.1038/s41598-021-87876-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/31/2021] [Indexed: 01/25/2023] Open
Abstract
Mitochondria receive cholesterol from late endosomes and lysosomes (LE/LYSs) or from the plasma membrane for production of oxysterols and steroid hormones. This process depends on the endo-lysosomal sterol transfer protein Niemann Pick C2 (NPC2). Using the intrinsically fluorescent cholesterol analog, cholestatrienol, we directly observe sterol transport to mitochondria in fibroblasts upon treating NPC2 deficient human fibroblasts with NPC2 protein. Soft X-ray tomography reveals the ultrastructure of mitochondria and discloses close contact to endosome-like organelles. Using fluorescence microscopy, we localize endo-lysosomes containing NPC2 relative to mitochondria based on the Euclidian distance transform and use statistical inference to show that about 30% of such LE/LYSs are in contact to mitochondria in human fibroblasts. Using Markov Chain Monte Carlo image simulations, we show that interaction between both organelle types, a defining feature of membrane contact sites (MCSs) can give rise to the observed spatial organelle distribution. We devise a protocol to determine the surface fraction of endo-lysosomes in contact with mitochondria and show that this fraction does not depend on functional NPC1 or NPC2 proteins. Finally, we localize MCSs between LE/LYSs containing NPC2 and mitochondria in time-lapse image sequences and show that they either form transiently or remain stable for tens of seconds. Lasting MCSs between endo-lysosomes containing NPC2 and mitochondria move by slow anomalous sub-diffusion, providing location and time for sterol transport between both organelles. Our quantitative imaging strategy will be of high value for characterizing the dynamics and function of MCSs between various organelles in living cells.
Collapse
Affiliation(s)
- Alice Dupont Juhl
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Christian W Heegaard
- Department of Molecular Biology and Genetics, University of Aarhus, 8000, Aarhus C, Denmark
| | - Stephan Werner
- Department of X-Ray Microscopy, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Gerd Schneider
- Department of X-Ray Microscopy, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489, Berlin, Germany
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University, St. Louis, MO, 63110, USA
| | - Douglas F Covey
- Department of Developmental Biology, Washington University, St. Louis, MO, 63110, USA
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
| |
Collapse
|