1
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Jang JS, Hong SJ, Mo S, Kim MK, Kim YG, Lee Y, Kim HH. PINK1 restrains periodontitis-induced bone loss by preventing osteoclast mitophagy impairment. Redox Biol 2024; 69:103023. [PMID: 38181706 PMCID: PMC10789640 DOI: 10.1016/j.redox.2023.103023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 12/21/2023] [Accepted: 12/28/2023] [Indexed: 01/07/2024] Open
Abstract
The oral colonization of periodontal pathogens onto gingival tissues establishes hypoxic microenvironment, often disrupting periodontal homeostasis in conjunction with oxidative stress. The association between reactive oxygen species (ROS) and osteolytic periodontitis have been suggested by recent studies. PTEN-induced kinase 1 (PINK1), a mitochondrial serine/threonine kinase, is an essential protein for mitochondrial quality control as it protects cells from oxidative stress by promoting degradation of damaged mitochondria through mitophagy. However, the pathophysiological roles of PINK1 in osteoclast-mediated bone loss have not been explored. Here we aimed to determine whether PINK1 plays a role in the regulation of osteoclastogenesis and alveolar bone resorption associated with periodontitis. C57BL/6 wild type (WT) and Pink1 knockout (KO) mice were subjected to ligature-induced periodontitis (LIP), and alveolar bones were evaluated by μCT-analysis and tartrate-resistant acid phosphatase (TRAP) staining. The μCT-analysis showed that bone volume fraction and travecular thickness were lower in Pink1 KO compared to WT mice. The number of TRAP-positive osteoclasts was markedly increased in the periodontal tissues of Pink1 KO mice with LIP. The genetic silencing or deletion of Pink1 promoted excessive osteoclast differentiation and bone resorption in vitro, as respectively indicated by TRAP staining and resorption pits on dentin slices. PINK1 deficiency led to mitochondrial instabilities as indicated by confocal microscopy of mitochondrial ROS, mitochondrial oxygen consumption rate (OCR) analysis, and transmission electron microscopy (TEM). Consequently, a significant increase in Ca2+-nuclear factor of activated T cells 1 (NFATc1) signaling was also found. On the other hand, restoration of mitophagy and autophagy by spermidine (SPD) treatment and the resolution of oxidative stress by N-acetyl-l-cysteine (NAC) treatment protected PINK1 deficiency-induced excessive generation of osteoclasts. Taken together, our findings demonstrate that PINK1 is essential for maintaining mitochondrial homeostasis during osteoclast differentiation. Therefore, targeting PINK1 may provide a novel therapeutic strategy for severe periodontitis with fulminant osteolysis.
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Affiliation(s)
- Ji Sun Jang
- Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, 03080, Republic of Korea
| | - Seo Jin Hong
- Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, 03080, Republic of Korea
| | - Shenzheng Mo
- Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, 03080, Republic of Korea
| | - Min Kyung Kim
- Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, 03080, Republic of Korea
| | - Yong-Gun Kim
- Department of Periodontology, School of Dentistry, Kyungpook National University, Daegu, 41940, Republic of Korea
| | - Youngkyun Lee
- Department of Biochemistry, School of Dentistry, Kyungpook National University, Daegu, 41940, Republic of Korea
| | - Hong-Hee Kim
- Department of Cell and Developmental Biology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul, 03080, Republic of Korea.
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2
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Deng Y, Xiao J, Ma L, Wang C, Wang X, Huang X, Cao Z. Mitochondrial Dysfunction in Periodontitis and Associated Systemic Diseases: Implications for Pathomechanisms and Therapeutic Strategies. Int J Mol Sci 2024; 25:1024. [PMID: 38256098 PMCID: PMC10816612 DOI: 10.3390/ijms25021024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 01/04/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
Periodontitis is a chronic infectious disorder damaging periodontal tissues, including the gingiva, periodontal ligament, cementum, and alveolar bone. It arises from the complex interplay between pathogenic oral bacteria and host immune response. Contrary to the previous view of "energy factories", mitochondria have recently been recognized as semi-autonomous organelles that fine-tune cell survival, death, metabolism, and other functions. Under physiological conditions, periodontal tissue cells participate in dynamic processes, including differentiation, mineralization, and regeneration. These fundamental activities depend on properly functioning mitochondria, which play a crucial role through bioenergetics, dynamics, mitophagy, and quality control. However, during the initiation and progression of periodontitis, mitochondrial quality control is compromised due to a range of challenges, such as bacterial-host interactions, inflammation, and oxidative stress. Currently, mounting evidence suggests that mitochondria dysfunction serves as a common pathological mechanism linking periodontitis with systemic conditions like type II diabetes, obesity, and cardiovascular diseases. Therefore, targeting mitochondria to intervene in periodontitis and multiple associated systemic diseases holds great therapeutic potential. This review provides advanced insights into the interplay between mitochondria, periodontitis, and associated systemic diseases. Moreover, we emphasize the significance of diverse therapeutic modulators and signaling pathways that regulate mitochondrial function in periodontal and systemic cells.
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Affiliation(s)
- Yifei Deng
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; (Y.D.)
| | - Junhong Xiao
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; (Y.D.)
| | - Li Ma
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; (Y.D.)
- Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China
| | - Chuan Wang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; (Y.D.)
- Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China
| | - Xiaoxuan Wang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; (Y.D.)
- Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China
| | - Xin Huang
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; (Y.D.)
- Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China
| | - Zhengguo Cao
- State Key Laboratory of Oral & Maxillofacial Reconstruction and Regeneration, Key Laboratory of Oral Biomedicine Ministry of Education, Hubei Key Laboratory of Stomatology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China; (Y.D.)
- Department of Periodontology, School & Hospital of Stomatology, Wuhan University, Wuhan 430079, China
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3
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Srivastava V, Gross E. Mitophagy-promoting agents and their ability to promote healthy-aging. Biochem Soc Trans 2023; 51:1811-1846. [PMID: 37650304 PMCID: PMC10657188 DOI: 10.1042/bst20221363] [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: 04/13/2023] [Revised: 08/07/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023]
Abstract
The removal of damaged mitochondrial components through a process called mitochondrial autophagy (mitophagy) is essential for the proper function of the mitochondrial network. Hence, mitophagy is vital for the health of all aerobic animals, including humans. Unfortunately, mitophagy declines with age. Many age-associated diseases, including Alzheimer's and Parkinson's, are characterized by the accumulation of damaged mitochondria and oxidative damage. Therefore, activating the mitophagy process with small molecules is an emerging strategy for treating multiple aging diseases. Recent studies have identified natural and synthetic compounds that promote mitophagy and lifespan. This article aims to summarize the existing knowledge about these substances. For readers' convenience, the knowledge is presented in a table that indicates the chemical data of each substance and its effect on lifespan. The impact on healthspan and the molecular mechanism is reported if known. The article explores the potential of utilizing a combination of mitophagy-inducing drugs within a therapeutic framework and addresses the associated challenges of this strategy. Finally, we discuss the process that balances mitophagy, i.e. mitochondrial biogenesis. In this process, new mitochondrial components are generated to replace the ones cleared by mitophagy. Furthermore, some mitophagy-inducing substances activate biogenesis (e.g. resveratrol and metformin). Finally, we discuss the possibility of combining mitophagy and biogenesis enhancers for future treatment. In conclusion, this article provides an up-to-date source of information about natural and synthetic substances that activate mitophagy and, hopefully, stimulates new hypotheses and studies that promote healthy human aging worldwide.
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Affiliation(s)
- Vijigisha Srivastava
- Faculty of Medicine, IMRIC Department of Biochemistry and Molecular Biology, The Hebrew University of Jerusalem, PO Box 12271, Jerusalem, Israel
| | - Einav Gross
- Faculty of Medicine, IMRIC Department of Biochemistry and Molecular Biology, The Hebrew University of Jerusalem, PO Box 12271, Jerusalem, Israel
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4
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Chlebek C, Rosen CJ. The Role of Bone Cell Energetics in Altering Bone Quality and Strength in Health and Disease. Curr Osteoporos Rep 2023; 21:1-10. [PMID: 36435911 DOI: 10.1007/s11914-022-00763-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/26/2022] [Indexed: 11/28/2022]
Abstract
PURPOSE OF REVIEW Bone quality and strength are diminished with age and disease but can be improved by clinical intervention. Energetic pathways are essential for cellular function and drive osteogenic signaling within bone cells. Altered bone quality is associated with changes in the energetic activity of bone cells following diet-based or therapeutic interventions. Energetic pathways may directly or indirectly contribute to changes in bone quality. The goal of this review is to highlight tissue-level and bioenergetic changes in bone health and disease. RECENT FINDINGS Bone cell energetics are an expanding field of research. Early literature primarily focused on defining energetic activation throughout the lifespan of bone cells. Recent studies have begun to connect bone energetic activity to health and disease. In this review, we highlight bone cell energetic demands, the effect of substrate availability on bone quality, altered bioenergetics associated with disease treatment and development, and additional biological factors influencing bone cell energetics. Bone cells use several energetic pathways during differentiation and maturity. The orchestration of bioenergetic pathways is critical for healthy cell function. Systemic changes in substrate availability alter bone quality, potentially due to the direct effects of altered bone cell bioenergetic activity. Bone cell bioenergetics may also contribute directly to the development and treatment of skeletal diseases. Understanding the role of energetic pathways in the cellular response to disease will improve patient treatment.
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Affiliation(s)
- Carolyn Chlebek
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME, USA
| | - Clifford J Rosen
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME, USA.
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5
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Zhang X, Jiang Y, Mao J, Ren X, Ji Y, Mao Y, Chen Y, Sun X, Pan Y, Ma J, Huang S. Hydroxytyrosol prevents periodontitis-induced bone loss by regulating mitochondrial function and mitogen-activated protein kinase signaling of bone cells. Free Radic Biol Med 2021; 176:298-311. [PMID: 34610362 DOI: 10.1016/j.freeradbiomed.2021.09.027] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/24/2021] [Accepted: 09/30/2021] [Indexed: 01/10/2023]
Abstract
Reactive oxygen species (ROS) overproduction promotes the alveolar bone loss during the development of periodontitis. Mitochondria are the principal source of ROS. Hydroxytyrosol (HT), a natural phenolic compound present in olive oil, is well known for its antioxidant and mitochondrial-protective prosperities. Nonetheless, the impact of HT on periodontitis and its related mechanisms underlying bone cell behavior remains unknown. Osteoclasts differentiated from RAW264.7 model and oxidative stress (OS) induced pre-osteoblast MC3T3-E1 cell injury model were treated with and without HT. Cell viability, apoptosis, differentiation, mitochondrial function along with mitogen-activated protein kinase (MAPK) signaling pathway were investigated. Meanwhile, the effect and related mechanisms of HT on bone loss in mice with periodontitis were also detected. HT inhibited osteoclast differentiation and prevented OS induced pre-osteoblast cells injury via regulating mitochondrial function as well as ERK and JNK signaling pathways. Moreover, HT attenuated the alveolar bone loss, increased bone forming activity, inhibited the osteoclasts differentiation and decreased the level of OS in mice with periodontitis. Our findings, for the first time, revealed a novel function of HT in bone remodeling of periodontitis, and highlighted its therapeutical potential for the prevention/treatment of periodontitis.
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Affiliation(s)
- Xiaorong Zhang
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Endodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yun Jiang
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Jiajie Mao
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Xuekun Ren
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Endodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yinghui Ji
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yixin Mao
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yang Chen
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Xiaoyu Sun
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Periodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yihuai Pan
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Endodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China.
| | - Jianfeng Ma
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China.
| | - Shengbin Huang
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China; Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China.
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6
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Kim IS, Silwal P, Jo EK. Mitofusin 2, a key coordinator between mitochondrial dynamics and innate immunity. Virulence 2021; 12:2273-2284. [PMID: 34482801 PMCID: PMC8425681 DOI: 10.1080/21505594.2021.1965829] [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] [Indexed: 12/11/2022] Open
Abstract
Remodeling of mitochondrial dynamics and mitochondrial morphology plays a pivotal role in the maintenance of mitochondrial homeostasis in response to pathogenic attacks or stress stimuli. In addition to their role in metabolism and energy production, mitochondria participate in diverse biological functions, including innate immune responses driven by macrophages in response to infections or inflammatory stimuli. Mitofusin-2 (MFN2), a mitochondria-shaping protein regulating mitochondrial fusion and fission, plays a crucial role in linking mitochondrial function and innate immune responses. In this article, we review the role of MFN2 in the regulation of innate immune responses during viral and bacterial infections. We also summarize the current knowledge on the role of MFN2 in coordinating inflammatory, atherogenic, and fibrotic responses. MFN2-mediated crosstalk between mitochondrial dynamics and innate immune responses may determine the outcomes of pathogenic infections.
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Affiliation(s)
- In Soo Kim
- Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea.,Infection Control Convergence Research Center, Chungnam National University College of Medicine, Daejeon, Korea
| | - Prashanta Silwal
- Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea.,Infection Control Convergence Research Center, Chungnam National University College of Medicine, Daejeon, Korea
| | - Eun-Kyeong Jo
- Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea.,Infection Control Convergence Research Center, Chungnam National University College of Medicine, Daejeon, Korea
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7
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Jeong S, Seong JH, Kang JH, Lee DS, Yim M. Dynamin-related protein 1 positively regulates osteoclast differentiation and bone loss. FEBS Lett 2020; 595:58-67. [PMID: 33084048 DOI: 10.1002/1873-3468.13963] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 09/28/2020] [Accepted: 10/04/2020] [Indexed: 01/14/2023]
Abstract
Dynamin-related protein 1 (DRP1) is a mitochondrial membrane GTPase and regulates mitochondrial fission. In this study, we found that the cytokine RANKL increased the expression of DRP1 and its receptor proteins, Fis1, Mid49, and Mid 51, during osteoclast formation in mouse bone marrow-derived macrophages. Inactivation of the kinase GSK3β appeared to induce DRP1 expression. DRP1 knockdown or the DRP1 inhibitor Mdivi1 suppressed osteoclast differentiation via downregulation of c-Fos and NFATc1, the key transcription factor for osteoclast formation. Finally, the DRP1 inhibitor suppressed lipopolysaccharide-induced osteoclast formation in a calvarial model and ovariectomy-induced bone loss in vivo. Taken together, our data demonstrate that DRP1 positively contributes to RANKL-induced osteoclast differentiation by regulating the c-Fos-NFATc1 axis, suggesting the importance of mitochondrial DRP1 in osteoclastogenesis.
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Affiliation(s)
- Sol Jeong
- College of Pharmacy, Sookmyung Women's University, Seoul, Korea
| | - Ji Hye Seong
- College of Pharmacy, Sookmyung Women's University, Seoul, Korea
| | - Ju-Hee Kang
- College of Pharmacy, Sookmyung Women's University, Seoul, Korea
| | - Dong-Seok Lee
- College of Natural Sciences, Kyungpook National University, Daegu, Korea
| | - Mijung Yim
- College of Pharmacy, Sookmyung Women's University, Seoul, Korea
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8
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Machuca-Gayet I, Quinaux T, Bertholet-Thomas A, Gaillard S, Claramunt-Taberner D, Acquaviva-Bourdain C, Bacchetta J. Bone Disease in Nephropathic Cystinosis: Beyond Renal Osteodystrophy. Int J Mol Sci 2020; 21:ijms21093109. [PMID: 32354056 PMCID: PMC7246679 DOI: 10.3390/ijms21093109] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 04/23/2020] [Accepted: 04/27/2020] [Indexed: 12/20/2022] Open
Abstract
Patients with chronic kidney disease (CKD) display significant mineral and bone disorders (CKD-MBD) that induce significant cardiovascular, growth and bone comorbidities. Nephropathic cystinosis is an inherited metabolic disorder caused by the lysosomal accumulation of cystine due to mutations in the CTNS gene encoding cystinosin, and leads to end-stage renal disease within the second decade. The cornerstone of management relies on cysteamine therapy to decrease lysosomal cystine accumulation in target organs. However, despite cysteamine therapy, patients display severe bone symptoms, and the concept of “cystinosis metabolic bone disease” is currently emerging. Even though its exact pathophysiology remains unclear, at least five distinct but complementary entities can explain bone impairment in addition to CKD-MBD: long-term consequences of renal Fanconi syndrome, malnutrition and copper deficiency, hormonal disturbances, myopathy, and intrinsic/iatrogenic bone defects. Direct effects of both CTNS mutation and cysteamine on osteoblasts and osteoclasts are described. Thus, the main objective of this manuscript is not only to provide a clinical update on bone disease in cystinosis, but also to summarize the current experimental evidence demonstrating a functional impairment of bone cells in this disease and to discuss new working hypotheses that deserve future research in the field.
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Affiliation(s)
- Irma Machuca-Gayet
- Pathophysiology, Diagnosis and Treatment of Bone Diseases, INSERM UMR 1033, 69008 Lyon, France; (I.M.-G.); (T.Q.); (D.C.-T.)
| | - Thomas Quinaux
- Pathophysiology, Diagnosis and Treatment of Bone Diseases, INSERM UMR 1033, 69008 Lyon, France; (I.M.-G.); (T.Q.); (D.C.-T.)
- Centre de Référence des Maladies Rénales Rares, Centre de Référence des Maladies Rares du Calcium et du Phosphore, Hôpital Femme Mère Enfant, 69500 Bron, France;
| | - Aurélia Bertholet-Thomas
- Centre de Référence des Maladies Rénales Rares, Centre de Référence des Maladies Rares du Calcium et du Phosphore, Hôpital Femme Mère Enfant, 69500 Bron, France;
| | - Ségolène Gaillard
- INSERM CIC 1407, CNRS UMR 5558 and Service de Pharmacotoxicologie Clinique, Hospices Civils de Lyon, 69500 Bron, France;
| | - Débora Claramunt-Taberner
- Pathophysiology, Diagnosis and Treatment of Bone Diseases, INSERM UMR 1033, 69008 Lyon, France; (I.M.-G.); (T.Q.); (D.C.-T.)
| | | | - Justine Bacchetta
- Pathophysiology, Diagnosis and Treatment of Bone Diseases, INSERM UMR 1033, 69008 Lyon, France; (I.M.-G.); (T.Q.); (D.C.-T.)
- Centre de Référence des Maladies Rénales Rares, Centre de Référence des Maladies Rares du Calcium et du Phosphore, Hôpital Femme Mère Enfant, 69500 Bron, France;
- Faculté de Médecine Lyon Est, Université de Lyon, 69008 Lyon, France
- Correspondence: ; Tel.: +33-4-27-85-61-30
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9
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Ballard A, Zeng R, Zarei A, Shao C, Cox L, Yan H, Franco A, Dorn GW, Faccio R, Veis DJ. The tethering function of mitofusin2 controls osteoclast differentiation by modulating the Ca 2+-NFATc1 axis. J Biol Chem 2020; 295:6629-6640. [PMID: 32165499 DOI: 10.1074/jbc.ra119.012023] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/06/2020] [Indexed: 12/16/2022] Open
Abstract
Dynamic regulation of the mitochondrial network by mitofusins (MFNs) modulates energy production, cell survival, and many intracellular signaling events, including calcium handling. However, the relative importance of specific mitochondrial functions and their dependence on MFNs vary greatly among cell types. Osteoclasts have many mitochondria, and increased mitochondrial biogenesis and oxidative phosphorylation enhance bone resorption, but little is known about the mitochondrial network or MFNs in osteoclasts. Because expression of each MFN isoform increases with osteoclastogenesis, we conditionally deleted MFN1 and MFN2 (double conditional KO (dcKO)) in murine osteoclast precursors, finding that this increased bone mass in young female mice and abolished osteoclast precursor differentiation into mature osteoclasts in vitro Defective osteoclastogenesis was reversed by overexpression of MFN2 but not MFN1; therefore, we generated mice lacking only MFN2 in osteoclasts. MFN2-deficient female mice had increased bone mass at 1 year and resistance to Receptor Activator of NF-κB Ligand (RANKL)-induced osteolysis at 8 weeks. To explore whether MFN-mediated tethering or mitophagy is important for osteoclastogenesis, we overexpressed MFN2 variants defective in either function in dcKO precursors and found that, although mitophagy was dispensable for differentiation, tethering was required. Because the master osteoclastogenic transcriptional regulator nuclear factor of activated T cells 1 (NFATc1) is calcium-regulated, we assessed calcium release from the endoplasmic reticulum and store-operated calcium entry and found that the latter was blunted in dcKO cells. Restored osteoclast differentiation by expression of intact MFN2 or the mitophagy-defective variant was associated with normalization of store-operated calcium entry and NFATc1 levels, indicating that MFN2 controls mitochondrion-endoplasmic reticulum tethering in osteoclasts.
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Affiliation(s)
- Anna Ballard
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.,Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Rong Zeng
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.,Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Allahdad Zarei
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.,Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Christine Shao
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.,Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Linda Cox
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.,Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Hui Yan
- Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, Missouri 63110.,Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri 63110.,Animal Nutrition Institute, Sichuan Agricultural University, Chengdu 611130, China
| | - Antonietta Franco
- Center for Pharmacogenomics, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Gerald W Dorn
- Center for Pharmacogenomics, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Roberta Faccio
- Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, Missouri 63110.,Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri 63110.,Shriners Hospitals for Children, St. Louis, Missouri 63110
| | - Deborah J Veis
- Division of Bone and Mineral Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110 .,Musculoskeletal Research Center, Washington University School of Medicine, St. Louis, Missouri 63110.,Shriners Hospitals for Children, St. Louis, Missouri 63110.,Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
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10
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Abstract
Owing to their ability to efficiently generate ATP required to sustain normal cell function, mitochondria are often considered the 'powerhouses of the cell'. However, our understanding of the role of mitochondria in cell biology recently expanded when we recognized that they are key platforms for a plethora of cell signalling cascades. This functional versatility is tightly coupled to constant reshaping of the cellular mitochondrial network in a series of processes, collectively referred to as mitochondrial membrane dynamics and involving organelle fusion and fission (division) as well as ultrastructural remodelling of the membrane. Accordingly, mitochondrial dynamics influence and often orchestrate not only metabolism but also complex cell signalling events, such as those involved in regulating cell pluripotency, division, differentiation, senescence and death. Reciprocally, mitochondrial membrane dynamics are extensively regulated by post-translational modifications of its machinery and by the formation of membrane contact sites between mitochondria and other organelles, both of which have the capacity to integrate inputs from various pathways. Here, we discuss mitochondrial membrane dynamics and their regulation and describe how bioenergetics and cellular signalling are linked to these dynamic changes of mitochondrial morphology.
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