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Panwar P, Olesen JB, Blum G, Delaisse JM, Søe K, Brömme D. Real-time analysis of osteoclast resorption and fusion dynamics in response to bone resorption inhibitors. Sci Rep 2024; 14:7358. [PMID: 38548807 PMCID: PMC10978898 DOI: 10.1038/s41598-024-57526-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 03/19/2024] [Indexed: 04/01/2024] Open
Abstract
Cathepsin K (CatK), an essential collagenase in osteoclasts (OCs), is a potential therapeutic target for the treatment of osteoporosis. Using live-cell imaging, we monitored the bone resorptive behaviour of OCs during dose-dependent inhibition of CatK by an ectosteric (Tanshinone IIA sulfonate) and an active site inhibitor (odanacatib). CatK inhibition caused drastic reductions in the overall resorption speed of OCs. At IC50 CatK-inhibitor concentration, OCs reduced about 40% of their trench-forming capacity and at fourfold IC50 concentrations, a > 95% reduction was observed. The majority of CatK-inhibited OCs (~ 75%) were involved in resorption-migration-resorption episodes forming adjacent pits, while ~ 25% were stagnating OCs which remained associated with the same excavation. We also observed fusions of OCs during the resorption process both in control and inhibitor-treated conditions, which increased their resorption speeds by 30-50%. Inhibitor IC50-concentrations increased OC-fusion by twofold. Nevertheless, more fusion could not counterweigh the overall loss of resorption activity by inhibitors. Using an activity-based probe, we demonstrated the presence of active CatK at the resorbing front in pits and trenches. In conclusion, our data document how OCs respond to CatK-inhibition with respect to movement, bone resorption activity, and their attempt to compensate for inhibition by activating fusion.
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Affiliation(s)
- Preety Panwar
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Pharmaceutical Sciences, Elizabeth City State University, Elizabeth City, NC, USA
| | - Jacob Bastholm Olesen
- Clinical Cell Biology, Pathology Research Unit, Department of Clinical Research, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
- Department of Pathology, Odense University Hospital, Odense, Denmark
| | - Galia Blum
- Faculty of Medicine, Campus Ein Karem, The School of Pharmacy, Institute of Drug Research, The Hebrew University of Jerusalem, Room 407, 9112001, Jerusalem, Israel
| | - Jean-Marie Delaisse
- Clinical Cell Biology, Pathology Research Unit, Department of Clinical Research, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Kent Søe
- Clinical Cell Biology, Pathology Research Unit, Department of Clinical Research, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
- Department of Pathology, Odense University Hospital, Odense, Denmark.
- Department of Molecular Medicine, University of Southern Denmark, Odense, Denmark.
| | - Dieter Brömme
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of British Columbia, Vancouver, BC, Canada.
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
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2
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Takito J, Nonaka N. Osteoclasts at Bone Remodeling: Order from Order. Results Probl Cell Differ 2024; 71:227-256. [PMID: 37996681 DOI: 10.1007/978-3-031-37936-9_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
Osteoclasts are multinucleated bone-resorbing cells derived from the monocyte/macrophage lineage. The macrophage colony-stimulating factor/receptor activator of nuclear factor κB ligand (M-CSF/RANKL) signaling network governs the differentiation of precursor cells into fusion-competent mononucleated cells. Repetitive fusion of fusion-competent cells produces multinucleated osteoclasts. Osteoclasts are believed to die via apoptosis after bone resorption. However, recent studies have found that osteoclastogenesis in vivo proceeds by replacing the old nucleus of existing osteoclasts with a single newly differentiated mononucleated cell. Thus, the formation of new osteoclasts is minimal. Furthermore, the sizes of osteoclasts can change via cell fusion and fission in response to external conditions. On the other hand, osteoclastogenesis in vitro involves various levels of heterogeneity, including osteoclast precursors, mode of fusion, and properties of the differentiated osteoclasts. To better understand the origin of these heterogeneities and the plasticity of osteoclasts, we examine several processes of osteoclastogenesis in this review. Candidate mechanisms that create heterogeneity involve asymmetric cell division, osteoclast niche, self-organization, and mode of fusion and fission. Elucidation of the plasticity or fluctuation of the M-CSF/RANKL network should be an important topic for future researches.
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Affiliation(s)
- Jiro Takito
- Department of Oral Anatomy and Developmental Biology, School of Dentistry, Showa University, Tokyo, Japan.
| | - Naoko Nonaka
- Department of Oral Anatomy and Developmental Biology, School of Dentistry, Showa University, Tokyo, Japan
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3
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Jiang T, Xia T, Qiao F, Wang N, Jiang Y, Xin H. Role and Regulation of Transcription Factors in Osteoclastogenesis. Int J Mol Sci 2023; 24:16175. [PMID: 38003376 PMCID: PMC10671247 DOI: 10.3390/ijms242216175] [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: 09/24/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Bones serve mechanical and defensive functions, as well as regulating the balance of calcium ions and housing bone marrow.. The qualities of bones do not remain constant. Instead, they fluctuate throughout life, with functions increasing in some situations while deteriorating in others. The synchronization of osteoblast-mediated bone formation and osteoclast-mediated bone resorption is critical for maintaining bone mass and microstructure integrity in a steady state. This equilibrium, however, can be disrupted by a variety of bone pathologies. Excessive osteoclast differentiation can result in osteoporosis, Paget's disease, osteolytic bone metastases, and rheumatoid arthritis, all of which can adversely affect people's health. Osteoclast differentiation is regulated by transcription factors NFATc1, MITF, C/EBPα, PU.1, NF-κB, and c-Fos. The transcriptional activity of osteoclasts is largely influenced by developmental and environmental signals with the involvement of co-factors, RNAs, epigenetics, systemic factors, and the microenvironment. In this paper, we review these themes in regard to transcriptional regulation in osteoclastogenesis.
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Affiliation(s)
- Tao Jiang
- School of Pharmacy, Naval Medical University, Shanghai 200433, China; (T.J.); (T.X.); (F.Q.)
- School of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
| | - Tianshuang Xia
- School of Pharmacy, Naval Medical University, Shanghai 200433, China; (T.J.); (T.X.); (F.Q.)
| | - Fangliang Qiao
- School of Pharmacy, Naval Medical University, Shanghai 200433, China; (T.J.); (T.X.); (F.Q.)
| | - Nani Wang
- Department of Medicine, Zhejiang Academy of Traditional Chinese Medicine, Hangzhou 310007, China;
| | - Yiping Jiang
- School of Pharmacy, Naval Medical University, Shanghai 200433, China; (T.J.); (T.X.); (F.Q.)
| | - Hailiang Xin
- School of Pharmacy, Naval Medical University, Shanghai 200433, China; (T.J.); (T.X.); (F.Q.)
- School of Pharmacy, Fujian University of Traditional Chinese Medicine, Fuzhou 350122, China
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4
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Taira TM, Ramos-Junior ES, Melo PH, Costa-Silva CC, Alteen MG, Vocadlo DJ, Dias WB, Cunha FQ, Alves-Filho JC, Søe K, Fukada SY. HBP/O-GlcNAcylation Metabolic Axis Regulates Bone Resorption Outcome. J Dent Res 2023; 102:440-449. [PMID: 36749069 DOI: 10.1177/00220345221141043] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Osteoclasts play a key role in the regulation of bone mass and are highly active metabolically. Here we show that a metabolic reprogramming toward the hexosamine biosynthetic pathway (HBP) is required not only for osteoclast differentiation but also to determine the bone resorption mode during physiological and pathological bone remodeling. We found that pharmacological inhibition of O-GlcNAc transferase (OGT) significantly reduced protein O-GlcNAcylation and osteoclast differentiation. Accordingly, genetic deletion of OGT also inhibited osteoclast formation and downregulated critical markers related to osteoclasts differentiation and function (NFATc1, αvintegrin, cathepsin K). Indeed, cells treated with OSMI-1, an OGT inhibitor, also reduced nuclear translocation of NFATc1. Furthermore, the addition of exogenous N-acetylglucosamine (GlcNAc) strongly increased osteoclast formation and demineralization ability. Strikingly, our data show for the first time that O-GlcNAcylation facilitates an aggressive trench resorption mode in human cells. The incubation of osteoclasts with exogenous GlcNAc increases the percentage of erosion by trench while having no effect on pit resorption mode. Through time-lapse recording, we documented that osteoclasts making trenches moving across the bone surface are sensitive to GlcNAcylation. Finally, osteoclast-specific Ogt-deficient mice show increased bone density and reduced inflammation-induced bone loss during apical periodontitis model. We show that osteoclast-specific Ogt-deficient mice are less susceptible to develop bacterial-induced periapical lesion. Consistent with this, Ogt-deleted mice showed a decreased number of tartrate-resistant acid phosphatase-positive cells lining the apical periodontitis site. In summary, here we describe a hitherto undiscovered role of the HBP/O-GlcNAcylation axis tuning resorption mode and dictating bone resorption outcome.
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Affiliation(s)
- T M Taira
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, Avenida do Café, sn, 14040-903, Ribeirão Preto, Brazil
- Department of Pediatric, School of Dentistry of Ribeirão Preto, Preventive and Social Dentistry, University of São Paulo, Ribeirão Preto, Brazil
- Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, casa 3, 14049-900, Ribeirão Preto, Brazil
| | - E S Ramos-Junior
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, Avenida do Café, sn, 14040-903, Ribeirão Preto, Brazil
- Department of Oral Biology & Diagnostic Sciences, The Dental College of Georgia, Augusta University, Augusta, GA 30912, USA
| | - P H Melo
- Department of Pharmacology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Avenida Bandeirantes, 3900, 14049-900, Ribeirão Preto, Brazil
| | - C C Costa-Silva
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, Avenida do Café, sn, 14040-903, Ribeirão Preto, Brazil
| | - M G Alteen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, B.C. V5A 1S6 Canada
| | - D J Vocadlo
- Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, B.C. V5A 1S6 Canada
| | - W B Dias
- Laboratório de Glicobiologia Estrutural e Funcional, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Rio de Janeiro, Brazil
| | - F Q Cunha
- Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, casa 3, 14049-900, Ribeirão Preto, Brazil
- Department of Pharmacology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Avenida Bandeirantes, 3900, 14049-900, Ribeirão Preto, Brazil
| | - J C Alves-Filho
- Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, casa 3, 14049-900, Ribeirão Preto, Brazil
- Department of Pharmacology, School of Medicine of Ribeirao Preto, University of Sao Paulo, Avenida Bandeirantes, 3900, 14049-900, Ribeirão Preto, Brazil
| | - K Søe
- Clinical Cell Biology, Pathology Research Unit, Department of Clinical Research, University of Southern Denmark, 5230 Odense M, Denmark
- Clinical Cell Biology, Department of Molecular Medicine, University of Southern Denmark, 5230 Odense M, Denmark
- Clinical Cell Biology, Department of Pathology, Odense University Hospital, 5000 Odense C, Denmark
| | - S Y Fukada
- Department of BioMolecular Sciences, School of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, Avenida do Café, sn, 14040-903, Ribeirão Preto, Brazil
- Center for Research in Inflammatory Diseases, CRID, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes, 3900, casa 3, 14049-900, Ribeirão Preto, Brazil
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5
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Wang H, Lai Y, Xie Z, Lin Y, Cai Y, Xu Z, Chen J. Graphene Oxide-Modified Concentric Microgrooved Titanium Surfaces for the Dual Effects of Osteogenesis and Antiosteoclastogenesis. ACS APPLIED MATERIALS & INTERFACES 2022; 14:54500-54516. [PMID: 36454650 DOI: 10.1021/acsami.2c14271] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Surface modification is an effective method to resolve the biocompatibility, mechanical, and functional issues of various titanium implant materials. Therefore, many researchers have modified the implant surface to promote the osseointegration of the implant and improve the implant survival rate. In this study, we used photolithography to construct concentric microgrooves with widths of 10 μm and depths of 10 μm, to produce an osteon-mimetic concentric microgrooved titanium surface that was further modified with graphene oxide by silanization (GO-CMS). The modified surface had great biocompatibility and promoted the proliferation of bone marrow-derived mesenchymal stem cells (BMSCs) and RAW264.7 macrophages. The concentric microgrooves on the titanium surface guided cell migration, altered actin cytoskeleton, and caused the cells to arrange in concentric circles. The titanium surface of the GO-modified osteon-mimetic concentric microgrooves promoted the osteogenic differentiation of BMSCs and inhibited the osteoclastogenic differentiation of RAW264.7 cells. Subsequently, we constructed an indirect coculture system and found that RAW264.7 cells cultured on a GO-CMS material surface in a BMSC-conditioned medium (BCM) decreased receptor activator of nuclear factor-κB ligand (RANKL) secretion and increased OPG secretion and also that the BCM inhibited osteoclastogenic differentiation. Additionally, the secretion of OSM increased in BMSCs cultured in RAW264.7-conditioned medium (RCM) in the GO-CMS group, which in turn promoted the osteogenic differentiation of BMSCs. In conclusion, the titanium surface of GO-modified osteon-mimetic concentric microgrooves had dual effects of osteogenesis and antiosteoclastogenesis under single and coculture conditions, which is beneficial for implant osseointegration and is a promising method for the future direction of surface modifications of implants.
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Affiliation(s)
- Hong Wang
- School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
- Engineering Research Center of Stomatological Biomaterials, Fujian Province University, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
| | - Yingzhen Lai
- Department of Stomatology, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
- Engineering Research Center of Stomatological Biomaterials, Fujian Province University, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
| | - Zeyu Xie
- Department of Stomatology, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
- Engineering Research Center of Stomatological Biomaterials, Fujian Province University, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
| | - Yanyin Lin
- Department of Stomatology, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
- Engineering Research Center of Stomatological Biomaterials, Fujian Province University, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
| | - Yihuang Cai
- Department of Stomatology, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
- Engineering Research Center of Stomatological Biomaterials, Fujian Province University, Xiamen Medical College, Xiamen, Fujian 361023, P.R. China
| | - Zhiqiang Xu
- Department of Stomatology, Affiliated Hospital of Putian University, Putian, Fujian 351100, P.R. China
| | - Jiang Chen
- School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian 350000, P.R. China
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6
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Elson A, Anuj A, Barnea-Zohar M, Reuven N. The origins and formation of bone-resorbing osteoclasts. Bone 2022; 164:116538. [PMID: 36028118 DOI: 10.1016/j.bone.2022.116538] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 02/07/2023]
Abstract
Osteoclasts (OCLs) are hematopoietic cells whose physiological function is to degrade bone. OCLs are key players in the processes that determine and maintain the mass, shape, and physical properties of bone. OCLs adhere to bone tightly and degrade its matrix by secreting protons and proteases onto the underlying surface. The combination of low pH and proteases degrades the mineral and protein components of the matrix and forms a resorption pit; the degraded material is internalized by the cell and then secreted into the circulation. Insufficient or excessive activity of OCLs can lead to significant changes in bone and either cause or exacerbate symptoms of diseases, as in osteoporosis, osteopetrosis, and cancer-induced bone lysis. OCLs are derived from monocyte-macrophage precursor cells whose origins are in two distinct embryonic cell lineages - erythromyeloid progenitor cells of the yolk sac, and hematopoietic stem cells. OCLs are formed in a multi-stage process that is induced by the cytokines M-CSF and RANKL, during which the cells differentiate, fuse to form multi-nucleated cells, and then differentiate further to become mature, bone-resorbing OCLs. Recent studies indicate that OCLs can undergo fission in vivo to generate smaller cells, called "osteomorphs", that can be "re-cycled" by fusing with other cells to form new OCLs. In this review we describe OCLs and discuss their cellular origins and the cellular and molecular events that drive osteoclastogenesis.
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Affiliation(s)
- Ari Elson
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel.
| | - Anuj Anuj
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Maayan Barnea-Zohar
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nina Reuven
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
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7
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Omi M, Mishina Y. Roles of osteoclasts in alveolar bone remodeling. Genesis 2022; 60:e23490. [PMID: 35757898 PMCID: PMC9786271 DOI: 10.1002/dvg.23490] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/25/2022] [Accepted: 06/09/2022] [Indexed: 12/30/2022]
Abstract
Osteoclasts are large multinucleated cells from hematopoietic origin and are responsible for bone resorption. A balance between osteoclastic bone resorption and osteoblastic bone formation is critical to maintain bone homeostasis. The alveolar bone, also called the alveolar process, is the part of the jawbone that holds the teeth and supports oral functions. It differs from other skeletal bones in several aspects: its embryonic cellular origin, the form of ossification, and the presence of teeth and periodontal tissues; hence, understanding the unique characteristic of the alveolar bone remodeling is important to maintain oral homeostasis. Excessive osteoclastic bone resorption is one of the prominent features of bone diseases in the jaw such as periodontitis. Therefore, inhibiting osteoclast formation and bone resorptive process has been the target of therapeutic intervention. Understanding the mechanisms of osteoclastic bone resorption is critical for the effective treatment of bone diseases in the jaw. In this review, we discuss basic principles of alveolar bone remodeling with a specific focus on the osteoclastic bone resorptive process and its unique functions in the alveolar bone. Lastly, we provide perspectives on osteoclast-targeted therapies and regenerative approaches associated with bone diseases in the jaw.
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Affiliation(s)
- Maiko Omi
- Department of Biologic and Materials Sciences & ProsthodonticsUniversity of Michigan School of DentistryAnn ArborMichiganUSA
| | - Yuji Mishina
- Department of Biologic and Materials Sciences & ProsthodonticsUniversity of Michigan School of DentistryAnn ArborMichiganUSA
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8
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Yahara Y, Nguyen T, Ishikawa K, Kamei K, Alman BA. The origins and roles of osteoclasts in bone development, homeostasis and repair. Development 2022; 149:275249. [PMID: 35502779 PMCID: PMC9124578 DOI: 10.1242/dev.199908] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The mechanisms underlying bone development, repair and regeneration are reliant on the interplay and communication between osteoclasts and other surrounding cells. Osteoclasts are multinucleated monocyte lineage cells with resorptive abilities, forming the bone marrow cavity during development. This marrow cavity, essential to hematopoiesis and osteoclast-osteoblast interactions, provides a setting to investigate the origin of osteoclasts and their multi-faceted roles. This Review examines recent developments in the embryonic understanding of osteoclast origin, as well as interactions within the immune environment to regulate normal and pathological bone development, homeostasis and repair.
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Affiliation(s)
- Yasuhito Yahara
- Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC 27710, United States.,Department of Molecular and Medical Pharmacology, Faculty of Medicine, University of Toyama, Toyama, 930-0194, Japan.,Department of Orthopaedic Surgery, Faculty of Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Tuyet Nguyen
- Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC 27710, United States.,Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, United States
| | - Koji Ishikawa
- Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC 27710, United States.,Department of Orthopaedic Surgery, Showa University School of Medicine, Tokyo, 142-8666, Japan
| | - Katsuhiko Kamei
- Department of Orthopaedic Surgery, Faculty of Medicine, University of Toyama, Toyama, 930-0194, Japan
| | - Benjamin A Alman
- Department of Orthopaedic Surgery, Duke University School of Medicine, Durham, NC 27710, United States.,Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, United States
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9
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Wang Q, Xie J, Zhou C, Lai W. Substrate stiffness regulates the differentiation profile and functions of osteoclasts via cytoskeletal arrangement. Cell Prolif 2021; 55:e13172. [PMID: 34953003 PMCID: PMC8780927 DOI: 10.1111/cpr.13172] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/24/2021] [Accepted: 11/26/2021] [Indexed: 02/05/2023] Open
Abstract
Objectives Aging and common diseases alter the stiffness of bone tissue, causing changes to the microenvironment of the mechanosensitive bone cells. Osteoclasts, the sole bone‐resorbing cells, play a vital role in bone remodeling. This study was performed to elucidate the mechanism through which osteoclasts sense and react to substrate stiffness signals. Materials and methods We fabricated polydimethylsiloxane (PDMS) substrates of different stiffness degrees for osteoclast formation progressed from osteoclast precursors including bone marrow‐derived macrophages (BMMs) and RAW264.7 monocytes. Osteoclast differentiation in response to the stiffness signals was determined by examining the cell morphology, fusion/fission activities, transcriptional profile, and resorption function. Cytoskeletal changes and mechanosensitive adhesion molecules were also assessed. Results Stiffer PDMS substrates accelerated osteoclast differentiation, firstly observed by variations in their morphology and fusion/fission activities. Upregulation of canonical osteoclast markers (Nfatc1, Acp5, Ctsk, Camk2a, Mmp9, Rela, and Traf6) and the fusion master regulator DC‐stamp were detected on stiffer substrates, with similar increases in their bone resorption functions. Additionally, the activation of cytoskeleton‐associated adhesion molecules, including fibronectin and integrin αvβ3, followed by biochemical signaling cascades of paxillin, FAK, PKC, and RhoA, was detected on the stiffer substrates. Conclusions This is the first study to provide evidence proving that extracellular substrate stiffness is a strong determinant of osteoclast differentiation and functions. Higher stiffness upregulated the differentiation profile and activity of osteoclasts, revealing the mechanical regulation of osteoclast activity in bone homeostasis and diseases.
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Affiliation(s)
- Qingxuan Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Chenchen Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Pediatric Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Wenli Lai
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Orthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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10
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Dufrançais O, Mascarau R, Poincloux R, Maridonneau-Parini I, Raynaud-Messina B, Vérollet C. Cellular and molecular actors of myeloid cell fusion: podosomes and tunneling nanotubes call the tune. Cell Mol Life Sci 2021; 78:6087-6104. [PMID: 34296319 PMCID: PMC8429379 DOI: 10.1007/s00018-021-03875-x] [Citation(s) in RCA: 7] [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: 01/28/2021] [Revised: 05/25/2021] [Accepted: 06/05/2021] [Indexed: 12/22/2022]
Abstract
Different types of multinucleated giant cells (MGCs) of myeloid origin have been described; osteoclasts are the most extensively studied because of their importance in bone homeostasis. MGCs are formed by cell-to-cell fusion, and most types have been observed in pathological conditions, especially in infectious and non-infectious chronic inflammatory contexts. The precise role of the different MGCs and the mechanisms that govern their formation remain poorly understood, likely due to their heterogeneity. First, we will introduce the main populations of MGCs derived from the monocyte/macrophage lineage. We will then discuss the known molecular actors mediating the early stages of fusion, focusing on cell-surface receptors involved in the cell-to-cell adhesion steps that ultimately lead to multinucleation. Given that cell-to-cell fusion is a complex and well-coordinated process, we will also describe what is currently known about the evolution of F-actin-based structures involved in macrophage fusion, i.e., podosomes, zipper-like structures, and tunneling nanotubes (TNT). Finally, the localization and potential role of the key fusion mediators related to the formation of these F-actin structures will be discussed. This review intends to present the current status of knowledge of the molecular and cellular mechanisms supporting multinucleation of myeloid cells, highlighting the gaps still existing, and contributing to the proposition of potential disease-specific MGC markers and/or therapeutic targets.
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Affiliation(s)
- Ophélie Dufrançais
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Rémi Mascarau
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- International Associated Laboratory (LIA) CNRS "IM-TB/HIV" (1167), Toulouse, France
- International Associated Laboratory (LIA) CNRS "IM-TB/HIV" (1167), Buenos Aires, Argentina
| | - Renaud Poincloux
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Isabelle Maridonneau-Parini
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France
- International Associated Laboratory (LIA) CNRS "IM-TB/HIV" (1167), Toulouse, France
| | - Brigitte Raynaud-Messina
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.
- International Associated Laboratory (LIA) CNRS "IM-TB/HIV" (1167), Toulouse, France.
- International Associated Laboratory (LIA) CNRS "IM-TB/HIV" (1167), Buenos Aires, Argentina.
| | - Christel Vérollet
- Institut de Pharmacologie et Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, Toulouse, France.
- International Associated Laboratory (LIA) CNRS "IM-TB/HIV" (1167), Toulouse, France.
- International Associated Laboratory (LIA) CNRS "IM-TB/HIV" (1167), Buenos Aires, Argentina.
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11
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CD13 is a critical regulator of cell-cell fusion in osteoclastogenesis. Sci Rep 2021; 11:10736. [PMID: 34031489 PMCID: PMC8144195 DOI: 10.1038/s41598-021-90271-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/07/2021] [Indexed: 12/04/2022] Open
Abstract
The transmembrane aminopeptidase CD13 is highly expressed in cells of the myeloid lineage, regulates dynamin-dependent receptor endocytosis and recycling and is a necessary component of actin cytoskeletal organization. Here, we show that CD13-deficient mice present a low bone density phenotype with increased numbers of osteoclasts per bone surface, but display a normal distribution of osteoclast progenitor populations in the bone marrow and periphery. In addition, the bone formation and mineral apposition rates are similar between genotypes, indicating a defect in osteoclast-specific function in vivo. Lack of CD13 led to exaggerated in vitro osteoclastogenesis as indicated by significantly enhanced fusion of bone marrow-derived multinucleated osteoclasts in the presence of M-CSF and RANKL, resulting in abnormally large cells containing remarkably high numbers of nuclei. Mechanistically, while expression levels of the fusion-regulatory proteins dynamin and DC-STAMP1 must be downregulated for fusion to proceed, these are aberrantly sustained at high levels even in CD13-deficient mature multi-nucleated osteoclasts. Further, the stability of fusion-promoting proteins is maintained in the absence of CD13, implicating CD13 in protein turnover mechanisms. Together, we conclude that CD13 may regulate cell–cell fusion by controlling the expression and localization of key fusion regulatory proteins that are critical for osteoclast fusion.
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12
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Barnea-Zohar M, Winograd-Katz SE, Shalev M, Arman E, Reuven N, Roth L, Golani O, Stein M, Thalji F, Kanaan M, Tuckermann J, Geiger B, Elson A. An SNX10-dependent mechanism downregulates fusion between mature osteoclasts. J Cell Sci 2021; 134:261809. [PMID: 33975343 PMCID: PMC8182410 DOI: 10.1242/jcs.254979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 03/19/2021] [Indexed: 01/13/2023] Open
Abstract
Homozygosity for the R51Q mutation in sorting nexin 10 (SNX10) inactivates osteoclasts (OCLs) and induces autosomal recessive osteopetrosis in humans and in mice. We show here that the fusion of wild-type murine monocytes to form OCLs is highly regulated, and that its extent is limited by blocking fusion between mature OCLs. In contrast, monocytes from homozygous R51Q SNX10 mice fuse uncontrollably, forming giant dysfunctional OCLs that can become 10- to 100-fold larger than their wild-type counterparts. Furthermore, mutant OCLs display reduced endocytotic activity, suggesting that their deregulated fusion is due to alterations in membrane homeostasis caused by loss of SNX10 function. This is supported by the finding that the R51Q SNX10 protein is unstable and exhibits altered lipid-binding properties, and is consistent with a key role for SNX10 in vesicular trafficking. We propose that OCL size and functionality are regulated by a cell-autonomous SNX10-dependent mechanism that downregulates fusion between mature OCLs. The R51Q mutation abolishes this regulatory activity, leading to excessive fusion, loss of bone resorption capacity and, consequently, to an osteopetrotic phenotype in vivo. This article has an associated First Person interview with the joint first authors of the paper. Summary: Fusion of monocytes to become bone-resorbing osteoclasts is limited by an SNX10-dependent cell-autonomous mechanism. Loss of SNX10 function deregulates fusion and generates giant inactive osteoclasts.
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Affiliation(s)
- Maayan Barnea-Zohar
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Moran Shalev
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Esther Arman
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nina Reuven
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Lee Roth
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ofra Golani
- Department of Life Sciences Core Facilities, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Merle Stein
- Department of Biology, Institute of Comparative Molecular Endocrinology, University of Ulm, 89081 Ulm, Germany
| | - Fadi Thalji
- Department of Orthopedics, Istishari Arab Hospital, Ramallah, Palestine
| | - Moien Kanaan
- Hereditary Research Laboratory and Department of Life Sciences, Bethlehem University, Bethlehem 0045866, Palestine
| | - Jan Tuckermann
- Department of Biology, Institute of Comparative Molecular Endocrinology, University of Ulm, 89081 Ulm, Germany
| | - Benjamin Geiger
- Department of Immunology, The Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ari Elson
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot 76100, Israel
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13
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Shalev M, Arman E, Stein M, Cohen-Sharir Y, Brumfeld V, Kapishnikov S, Royal I, Tuckermann J, Elson A. PTPRJ promotes osteoclast maturation and activity by inhibiting Cbl-mediated ubiquitination of NFATc1 in late osteoclastogenesis. FEBS J 2021; 288:4702-4723. [PMID: 33605542 DOI: 10.1111/febs.15778] [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: 10/03/2020] [Revised: 01/22/2021] [Accepted: 02/18/2021] [Indexed: 11/28/2022]
Abstract
Bone-resorbing osteoclasts (OCLs) are multinucleated phagocytes, whose central roles in regulating bone formation and homeostasis are critical for normal health and development. OCLs are produced from precursor monocytes in a multistage process that includes initial differentiation, cell-cell fusion, and subsequent functional and morphological maturation; the molecular regulation of osteoclastogenesis is not fully understood. Here, we identify the receptor-type protein tyrosine phosphatase PTPRJ as an essential regulator specifically of OCL maturation. Monocytes from PTPRJ-deficient (JKO) mice differentiate and fuse normally, but their maturation into functional OCLs and their ability to degrade bone are severely inhibited. In agreement, mice lacking PTPRJ throughout their bodies or only in OCLs exhibit increased bone mass due to reduced OCL-mediated bone resorption. We further show that PTPRJ promotes OCL maturation by dephosphorylating the M-CSF receptor (M-CSFR) and Cbl, thus reducing the ubiquitination and degradation of the key osteoclastogenic transcription factor NFATc1. Loss of PTPRJ increases ubiquitination of NFATc1 and reduces its amounts at later stages of osteoclastogenesis, thereby inhibiting OCL maturation. PTPRJ thus fulfills an essential and cell-autonomous role in promoting OCL maturation by balancing between the pro- and anti-osteoclastogenic activities of the M-CSFR and maintaining NFATc1 expression during late osteoclastogenesis.
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Affiliation(s)
- Moran Shalev
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Esther Arman
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Merle Stein
- Institute of Comparative Molecular Endocrinology, University of Ulm, Germany
| | - Yael Cohen-Sharir
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Vlad Brumfeld
- Department of Chemical Research Support, The Weizmann Institute of Science, Rehovot, Israel
| | - Sergey Kapishnikov
- Department of Chemical Research Support, The Weizmann Institute of Science, Rehovot, Israel
| | - Isabelle Royal
- CRCHUM - Centre de Recherche du Centre Hospitalier de l'Université de Montréal, QC, Canada.,Institut du Cancer de Montréal, QC, Canada.,Department of Medicine, University of Montreal, QC, Canada
| | - Jan Tuckermann
- Institute of Comparative Molecular Endocrinology, University of Ulm, Germany
| | - Ari Elson
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
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14
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Osteoclasts Differentiation from Murine RAW 264.7 Cells Stimulated by RANKL: Timing and Behavior. BIOLOGY 2021; 10:biology10020117. [PMID: 33557437 PMCID: PMC7915339 DOI: 10.3390/biology10020117] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/24/2022]
Abstract
The development of multi-nucleated cells is critical for osteoclasts (OCs) maturation and function. Our objective was to extend knowledge on osteoclastogenesis, focusing on pre-OC fusion timing and behavior. RAW 264.7 cells, which is a murine monocyte-macrophage cell line, provide a valuable and widely used tool for in vitro studies on osteoclastogenesis mechanisms. Cells were treated with the receptor activator of nuclear factor κ-B ligand (RANKL) for 1-4 days and effects on cell morphology, cytoskeletal organization, protein distribution, and OC-specific gene expression examined by TEM, immunofluorescence, and qPCR. Multinucleated cells began to appear at two days of Receptor Activator of Nuclear factor κ-B Ligand (RANKL) stimulation, increasing in number and size in the following days, associated with morphological and cytoskeletal organization changes. Interesting cellular extensions were observed in three days within cells labeled with wheat germ agglutinin (WGA)-Fluorescein isothiocyanate (FITC). The membrane, cytoplasmic, or nuclear distribution of RANK, TRAF6, p-p38, pERK1/2, and NFATc1, respectively, was related to OCs maturation timing. The gene expression for transcription factors regulating osteoclastogenesis (NFATc1, c-fos, RelA, MITF), molecules involved in RANKL-signaling transduction (TRAF6), cytoskeleton regulation (RhoA), fusion (DC-STAMP), migration (MMP9), and OC-specific enzymes (TRAP, CtsK), showed different trends related to OC differentiation timing. Our findings provide an integrated view on the morphological and molecular changes occurring during RANKL stimulation of RAW 264.7 cells, which are important to better understand the OCs' maturation processes.
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15
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Søe K. Osteoclast Fusion: Physiological Regulation of Multinucleation through Heterogeneity-Potential Implications for Drug Sensitivity. Int J Mol Sci 2020; 21:E7717. [PMID: 33086479 PMCID: PMC7589811 DOI: 10.3390/ijms21207717] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 02/06/2023] Open
Abstract
Classically, osteoclast fusion consists of four basic steps: (1) attraction/migration, (2) recognition, (3) cell-cell adhesion, and (4) membrane fusion. In theory, this sounds like a straightforward simple linear process. However, it is not. Osteoclast fusion has to take place in a well-coordinated manner-something that is not simple. In vivo, the complex regulation of osteoclast formation takes place within the bone marrow-in time and space. The present review will focus on considering osteoclast fusion in the context of physiology and pathology. Special attention is given to: (1) regulation of osteoclast fusion in vivo, (2) heterogeneity of osteoclast fusion partners, (3) regulation of multi-nucleation, (4) implications for physiology and pathology, and (5) implications for drug sensitivity and side effects. The review will emphasize that more attention should be given to the human in vivo reality when interpreting the impact of in vitro and animal studies. This should be done in order to improve our understanding of human physiology and pathology, as well as to improve anti-resorptive treatment and reduce side effects.
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Affiliation(s)
- Kent Søe
- Clinical Cell Biology, Department of Pathology, Odense University Hospital, 5000 Odense C, Denmark; ; Tel.: +45-65-41-31-90
- Department of Clinical Research, University of Southern Denmark, 5230 Odense M, Denmark
- Department of Molecular Medicine, University of Southern Denmark, 5230 Odense M, Denmark
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16
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Takito J, Nakamura M. Heterogeneity and Actin Cytoskeleton in Osteoclast and Macrophage Multinucleation. Int J Mol Sci 2020; 21:ijms21186629. [PMID: 32927783 PMCID: PMC7554939 DOI: 10.3390/ijms21186629] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 02/07/2023] Open
Abstract
Osteoclast signatures are determined by two transcriptional programs, the lineage-determining transcription pathway and the receptor activator of nuclear factor kappa-B ligand (RANKL)-dependent differentiation pathways. During differentiation, mononuclear precursors become multinucleated by cell fusion. Recently, live-cell imaging has revealed a high level of heterogeneity in osteoclast multinucleation. This heterogeneity includes the difference in the differentiation states and the mobility of the fusion precursors, as well as the mode of fusion among the fusion precursors with different numbers of nuclei. In particular, fusion partners often form morphologically distinct actin-based linkages that allow two cells to exchange lipids and proteins before membrane fusion. However, the origin of this heterogeneity remains elusive. On the other hand, osteoclast multinucleation is sensitive to the environmental cues. Such cues promote the reorganization of the actin cytoskeleton, especially the formation and transformation of the podosome, an actin-rich punctate adhesion. This review covers the heterogeneity of osteoclast multinucleation at the pre-fusion stage with reference to the environment-dependent signaling pathway responsible for reorganizing the actin cytoskeleton. Furthermore, we compare osteoclast multinucleation with macrophage fusion, which results in multinucleated giant macrophages.
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17
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Fusion Potential of Human Osteoclasts In Vitro Reflects Age, Menopause, and In Vivo Bone Resorption Levels of Their Donors-A Possible Involvement of DC-STAMP. Int J Mol Sci 2020; 21:ijms21176368. [PMID: 32887359 PMCID: PMC7504560 DOI: 10.3390/ijms21176368] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/27/2020] [Accepted: 09/01/2020] [Indexed: 12/28/2022] Open
Abstract
It is well established that multinucleation is central for osteoclastic bone resorption. However, our knowledge on the mechanisms regulating how many nuclei an osteoclast will have is limited. The objective of this study was to investigate donor-related variations in the fusion potential of in vitro-generated osteoclasts. Therefore, CD14+ monocytes were isolated from 49 healthy female donors. Donor demographics were compared to the in vivo bone biomarker levels and their monocytes’ ability to differentiate into osteoclasts, showing that: (1) C-terminal telopeptide of type I collagen (CTX) and procollagen type I N-terminal propeptide (PINP) levels increase with age, (2) the number of nuclei per osteoclast in vitro increases with age, and (3) there is a positive correlation between the number of nuclei per osteoclast in vitro and CTX levels in vivo. Furthermore, the expression levels of the gene encoding dendritic cell-specific transmembrane protein (DCSTAMP) of osteoclasts in vitro correlated positively with the number of nuclei per osteoclast, CTX levels in vivo, and donor age. Our results furthermore suggest that these changes in gene expression may be mediated through age-related changes in DNA methylation levels. We conclude that both intrinsic factors and age-induced increase in fusion potential of osteoclasts could be contributing factors for the enhanced bone resorption in vivo, possibly caused by increased expression levels of DCSTAMP.
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18
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Gambari L, Grassi F, Roseti L, Grigolo B, Desando G. Learning from Monocyte-Macrophage Fusion and Multinucleation: Potential Therapeutic Targets for Osteoporosis and Rheumatoid Arthritis. Int J Mol Sci 2020; 21:ijms21176001. [PMID: 32825443 PMCID: PMC7504439 DOI: 10.3390/ijms21176001] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
Excessive bone resorption by osteoclasts (OCs) covers an essential role in developing bone diseases, such as osteoporosis (OP) and rheumatoid arthritis (RA). Monocytes or macrophages fusion and multinucleation (M-FM) are key processes for generating multinucleated mature cells with essential roles in bone remodelling. Depending on the phenotypic heterogeneity of monocyte/macrophage precursors and the extracellular milieu, two distinct morphological and functional cell types can arise mature OCs and giant cells (GCs). Despite their biological relevance in several physiological and pathological responses, many gaps exist in our understanding of their formation and role in bone, including the molecular determinants of cell fusion and multinucleation. Here, we outline fusogenic molecules during M-FM involved in OCs and GCs formation in healthy conditions and during OP and RA. Moreover, we discuss the impact of the inflammatory milieu on modulating macrophages phenotype and their differentiation towards mature cells. Methodological approach envisaged searches on Scopus, Web of Science Core Collection, and EMBASE databases to select relevant studies on M-FM, osteoclastogenesis, inflammation, OP, and RA. This review intends to give a state-of-the-art description of mechanisms beyond osteoclastogenesis and M-FM, with a focus on OP and RA, and to highlight potential biological therapeutic targets to prevent extreme bone loss.
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Affiliation(s)
| | | | - Livia Roseti
- Correspondence: (L.R.); (B.G.); Tel.: +39-051-6366090 (B.G.)
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19
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Osteoclast Multinucleation: Review of Current Literature. Int J Mol Sci 2020; 21:ijms21165685. [PMID: 32784443 PMCID: PMC7461040 DOI: 10.3390/ijms21165685] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/14/2022] Open
Abstract
Multinucleation is a hallmark of osteoclast maturation. The unique and dynamic multinucleation process not only increases cell size but causes functional alterations through reconstruction of the cytoskeleton, creating the actin ring and ruffled border that enable bone resorption. Our understanding of the molecular mechanisms underlying osteoclast multinucleation has advanced considerably in this century, especially since the identification of DC-STAMP and OC-STAMP as “master fusogens”. Regarding the molecules and pathways surrounding these STAMPs, however, only limited progress has been made due to the absence of their ligands. Various molecules and mechanisms other than the STAMPs are involved in osteoclast multinucleation. In addition, several preclinical studies have explored chemicals that may be able to target osteoclast multinucleation, which could enable us to control pathogenic bone metabolism more precisely. In this review, we will focus on recent discoveries regarding the STAMPs and other molecules involved in osteoclast multinucleation.
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20
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Vacher J, Bruccoleri M, Pata M. Ostm1 from Mouse to Human: Insights into Osteoclast Maturation. Int J Mol Sci 2020; 21:ijms21165600. [PMID: 32764302 PMCID: PMC7460669 DOI: 10.3390/ijms21165600] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 07/29/2020] [Accepted: 08/04/2020] [Indexed: 12/14/2022] Open
Abstract
The maintenance of bone mass is a dynamic process that requires a strict balance between bone formation and resorption. Bone formation is controlled by osteoblasts, while osteoclasts are responsible for resorption of the bone matrix. The opposite functions of these cell types have to be tightly regulated not only during normal bone development, but also during adult life, to maintain serum calcium homeostasis and sustain bone integrity to prevent bone fractures. Disruption of the control of bone synthesis or resorption can lead to an over accumulation of bone tissue in osteopetrosis or conversely to a net depletion of the bone mass in osteoporosis. Moreover, high levels of bone resorption with focal bone formation can cause Paget’s disease. Here, we summarize the steps toward isolation and characterization of the osteopetrosis associated trans-membrane protein 1 (Ostm1) gene and protein, essential for proper osteoclast maturation, and responsible when mutated for the most severe form of osteopetrosis in mice and humans.
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Affiliation(s)
- Jean Vacher
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, QC H2W 1R7, Canada; (M.B.); (M.P.)
- Departement de Medecine, Universite de Montreal, Montreal, QC H2W 1R7, Canada
- Department of Medicine, Division of Experimental Medicine, McGill University, Montreal, QC H3A 1A3, Canada
- Correspondence:
| | - Michael Bruccoleri
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, QC H2W 1R7, Canada; (M.B.); (M.P.)
- Departement de Medecine, Universite de Montreal, Montreal, QC H2W 1R7, Canada
| | - Monica Pata
- Institut de Recherches Cliniques de Montreal (IRCM), Montreal, QC H2W 1R7, Canada; (M.B.); (M.P.)
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21
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Tong L, Wang Y, Wang J, He F, Zhai J, Bai J, Zhu G. Radiation alters osteoclastogenesis by regulating the cytoskeleton and lytic enzymes in RAW 264.7 cells and mouse bone marrow-derived macrophages. Int J Radiat Biol 2020; 96:1296-1308. [PMID: 32687425 DOI: 10.1080/09553002.2020.1798542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE The aim of the present study was to investigate the duality of irradiation effect on osteoclastogenesis, particularly on the cytoskeleton and expression of lytic enzymes in osteoclast precursors. Therefore, the present study may serve as a useful reference for the prevention and treatment of radiation-induced bone loss in the clinic. MATERIALS AND METHODS Two typical osteoclast precursors, murine RAW 264.7 macrophage cells and mouse bone marrow-derived macrophages (BMMs), were exposed to radiation in the order of 0.25-8 Gy, and the effects on cell viability, TRAP activity and bone resorption were subsequently investigated. Furthermore, changes in the cytoskeleton, cell apoptosis, and expression of lytic enzymes in osteoclasts were examined to elucidate the molecular mechanism of the duality of irradiation on osteoclastogenesis. RESULTS Morphological changes and impaired viability were observed in RAW 264.7 cells and BMMs treated with 1-8 Gy irradiation with or without RANKL. However, the cell fusion tendency of osteoclasts was enhanced after 2 Gy irradiation, and an increased number of fused giant osteoclasts and enhanced F-actin ring formation were observed. Consistently, the bone resorption activity and the enzyme expression of TRAP, cathepsin K, matrix metalloproteinase 9, activator protein 1, and Caspase 9 were increased following irradiation with 2 Gy. Furthermore, intracellular ROS production and apoptosis of osteoclast precursors were increased. CONCLUSIONS Irradiation with 2 Gy inhibited the viability of osteoclast precursors, but increased osteoclastogenesis by enhancing cell fusion and increasing the secretion of lytic enzymes, which may be an important mechanism of radiation-induced bone loss.
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Affiliation(s)
- Ling Tong
- Institute of Radiation Medicine, Fudan University, Shanghai, PR China.,Shanghai Municipal Center for Disease Control & Prevention, Shanghai, PR China
| | - Yuyang Wang
- Institute of Radiation Medicine, Fudan University, Shanghai, PR China
| | - Jianping Wang
- Institute of Radiation Medicine, Fudan University, Shanghai, PR China
| | - Feilong He
- Institute of Radiation Medicine, Fudan University, Shanghai, PR China.,Shanghai Municipal Center for Disease Control & Prevention, Shanghai, PR China
| | - Jianglong Zhai
- Institute of Radiation Medicine, Fudan University, Shanghai, PR China
| | - Jiangtao Bai
- Institute of Radiation Medicine, Fudan University, Shanghai, PR China
| | - Guoying Zhu
- Institute of Radiation Medicine, Fudan University, Shanghai, PR China
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22
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Howaldt A, Hennig AF, Rolvien T, Rössler U, Stelzer N, Knaus A, Böttger S, Zustin J, Geißler S, Oheim R, Amling M, Howaldt HP, Kornak U. Adult Osteosclerotic Metaphyseal Dysplasia With Progressive Osteonecrosis of the Jaws and Abnormal Bone Resorption Pattern Due to a LRRK1 Splice Site Mutation. J Bone Miner Res 2020; 35:1322-1332. [PMID: 32119750 DOI: 10.1002/jbmr.3995] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 02/14/2020] [Accepted: 02/27/2020] [Indexed: 12/15/2022]
Abstract
Osteosclerotic metaphyseal dysplasia (OSMD) is a rare autosomal recessive sclerosing skeletal dysplasia. We report on a 34-year-old patient with sandwich vertebrae, platyspondyly, osteosclerosis of the tubular bones, pathologic fractures, and anemia. In the third decade, he developed osteonecrosis of the jaws, which was progressive in spite of repeated surgical treatment over a period of 11 years. An iliac crest bone biopsy revealed the presence of hypermineralized cartilage remnants, large multinucleated osteoclasts with abnormal morphology, and inadequate bone resorption typical for osteoclast-rich osteopetrosis. After exclusion of mutations in TCIRG1 and CLCN7 we performed trio-based exome sequencing. The novel homozygous splice-site mutation c.261G>A in the gene LRRK1 was found and co-segregated with the phenotype in the family. cDNA sequencing showed nearly complete skipping of exon 3 leading to a frameshift (p.Ala34Profs*33). Osteoclasts differentiated from the patient's peripheral blood monocytes were extremely large. Instead of resorption pits these cells were only capable of superficial erosion. Phosphorylation of L-plastin at position Ser5 was strongly reduced in patient-derived osteoclasts showing a loss of function of the mutated LRRK1 kinase protein. Our analysis indicates a strong overlap of LRRK1-related OSMD with other forms of intermediate osteopetrosis, but an exceptional abnormality of osteoclast resorption. Like in other osteoclast pathologies an increased risk for progressive osteonecrosis of the jaws should be considered in OSMD, an intermediate form of osteopetrosis. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.
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Affiliation(s)
- Antonia Howaldt
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,BIH Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Anna Floriane Hennig
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,BIH Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Freie Universität Berlin, Berlin, Germany
| | - Tim Rolvien
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Department of Orthopedics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Uta Rössler
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,BIH Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Nina Stelzer
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,BIH Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Alexej Knaus
- Institute for Genomic Statistics and Bioinformatics, University Hospital Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
| | - Sebastian Böttger
- Department for Maxillo Facial Surgery, Justus Liebig University Gießen, Gießen, Germany
| | - Jozef Zustin
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sven Geißler
- BIH Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ralf Oheim
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Hans-Peter Howaldt
- Department for Maxillo Facial Surgery, Justus Liebig University Gießen, Gießen, Germany
| | - Uwe Kornak
- Institut für Medizinische Genetik und Humangenetik, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,BIH Center for Regenerative Therapies, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Max Planck Institute for Molecular Genetics, Berlin, Germany.,Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
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23
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Søe K, Delaisse JM, Borggaard XG. Osteoclast formation at the bone marrow/bone surface interface: Importance of structural elements, matrix, and intercellular communication. Semin Cell Dev Biol 2020; 112:8-15. [PMID: 32563679 DOI: 10.1016/j.semcdb.2020.05.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/17/2020] [Accepted: 05/19/2020] [Indexed: 12/28/2022]
Abstract
Osteoclasts, the multinucleated cells responsible for bone resorption, have an enormous destructive power which demands to be kept under tight control. Accordingly, the identification of molecular signals directing osteoclastogenesis and switching on their resorptive activity have received much attention. Mandatory factors were identified, but a very essential aspect of the control mechanism of osteoclastic resorption, i.e. its spatial control, remains poorly understood. Under physiological conditions, multinucleated osteoclasts are only detected on the bone surface, while their mono-nucleated precursors are only in the bone marrow. How are pre-osteoclasts targeted to the bone surface? How is their progressive differentiation coordinated with their approach to the bone surface sites to be resorbed, which is where they finally fuse? Here we review the information on the bone marrow distribution of differentiating pre-osteoclasts relative to the position of the mandatory factors for their differentiation as well as relative to physical entities that may affect their access to the remodelling sites. This info allows recognizing an "osteoclastogenesis route" through the bone marrow and leading to the coincident fusion/resorption site - but also points to what still remains to be clarified regarding this route and regarding the restriction of fusion at the resorption site. Finally, we discuss the mechanism responsible for the start of resorption and its spatial extension. This review underscores that fully understanding the control of bone resorption requires to consider it in both space and time - which demands taking into account the context of bone tissue.
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Affiliation(s)
- Kent Søe
- Clinical Cell Biology, Department of Pathology, Odense University Hospital, 5000 Odense C, Denmark; Department of Clinical Research, University of Southern Denmark, 5230 Odense M, Denmark; Department of Molecular Medicine, University of Southern Denmark, 5230 Odense M, Denmark.
| | - Jean-Marie Delaisse
- Clinical Cell Biology, Department of Pathology, Odense University Hospital, 5000 Odense C, Denmark; Department of Clinical Research, University of Southern Denmark, 5230 Odense M, Denmark; Department of Molecular Medicine, University of Southern Denmark, 5230 Odense M, Denmark.
| | - Xenia Goldberg Borggaard
- Clinical Cell Biology, Department of Pathology, Odense University Hospital, 5000 Odense C, Denmark; Department of Clinical Research, University of Southern Denmark, 5230 Odense M, Denmark; Department of Molecular Medicine, University of Southern Denmark, 5230 Odense M, Denmark.
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24
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Kobayashi-Sun J, Yamamori S, Kondo M, Kuroda J, Ikegame M, Suzuki N, Kitamura KI, Hattori A, Yamaguchi M, Kobayashi I. Uptake of osteoblast-derived extracellular vesicles promotes the differentiation of osteoclasts in the zebrafish scale. Commun Biol 2020; 3:190. [PMID: 32327701 PMCID: PMC7181839 DOI: 10.1038/s42003-020-0925-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 03/25/2020] [Indexed: 02/07/2023] Open
Abstract
Differentiation of osteoclasts (OCs) from hematopoietic cells requires cellular interaction with osteoblasts (OBs). Due to the difficulty of live-imaging in the bone, however, the cellular and molecular mechanisms underlying intercellular communication involved in OC differentiation are still elusive. Here, we develop a fracture healing model using the scale of trap:GFP; osterix:mCherry transgenic zebrafish to visualize the interaction between OCs and OBs. Transplantation assays followed by flow cytometric analysis reveal that most trap:GFPhigh OCs in the fractured scale are detected in the osterix:mCherry+ fraction because of uptake of OB-derived extracellular vesicles (EVs). In vivo live-imaging shows that immature OCs actively interact with osterix:mCherry+ OBs and engulf EVs prior to convergence at the fracture site. In vitro cell culture assays show that OB-derived EVs promote OC differentiation via Rankl signaling. Collectively, these data suggest that EV-mediated intercellular communication with OBs plays an important role in the differentiation of OCs in bone tissue.
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Affiliation(s)
- Jingjing Kobayashi-Sun
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
| | - Shiori Yamamori
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
| | - Mao Kondo
- Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
| | - Junpei Kuroda
- Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Mika Ikegame
- Department of Oral Morphology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Okayama, 700-8525, Japan
| | - Nobuo Suzuki
- Noto Marine Laboratory, Institute of Nature and Environmental Technology, Division of Marine Environmental Studies, Kanazawa University, Noto-cho, Ishikawa, 927-0553, Japan
| | - Kei-Ichiro Kitamura
- Department of Clinical Laboratory Science, Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, 920-0942, Japan
| | - Atsuhiko Hattori
- Department of Biology, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Chiba, 272-0827, Japan
| | - Masaaki Yamaguchi
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan
| | - Isao Kobayashi
- Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, 920-1192, Japan.
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25
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Endogenous Retroviruses Activity as a Molecular Signature of Neurodevelopmental Disorders. Int J Mol Sci 2019; 20:ijms20236050. [PMID: 31801288 PMCID: PMC6928979 DOI: 10.3390/ijms20236050] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 11/26/2019] [Accepted: 11/28/2019] [Indexed: 12/20/2022] Open
Abstract
Human endogenous retroviruses (HERVs) are genetic elements resulting from relics of ancestral infection of germline cells, now recognized as cofactors in the etiology of several complex diseases. Here we present a review of findings supporting the role of the abnormal HERVs activity in neurodevelopmental disorders. The derailment of brain development underlies numerous neuropsychiatric conditions, likely starting during prenatal life and carrying on during subsequent maturation of the brain. Autism spectrum disorders, attention deficit hyperactivity disorders, and schizophrenia are neurodevelopmental disorders that arise clinically during early childhood or adolescence, currently attributed to the interplay among genetic vulnerability, environmental risk factors, and maternal immune activation. The role of HERVs in human embryogenesis, their intrinsic responsiveness to external stimuli, and the interaction with the immune system support the involvement of HERVs in the derailed neurodevelopmental process. Although definitive proofs that HERVs are involved in neurobehavioral alterations are still lacking, both preclinical models and human studies indicate that the abnormal expression of ERVs could represent a neurodevelopmental disorders-associated biological trait in affected individuals and their parents.
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26
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Søe K, Andersen TL, Hinge M, Rolighed L, Marcussen N, Delaisse JM. Coordination of Fusion and Trafficking of Pre-osteoclasts at the Marrow-Bone Interface. Calcif Tissue Int 2019; 105:430-445. [PMID: 31236622 DOI: 10.1007/s00223-019-00575-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Accepted: 06/14/2019] [Indexed: 12/16/2022]
Abstract
Fusion is the final osteoclast differentiation step leading to bone resorption. In healthy trabecular bone, osteoclast fusion is restricted to bone surfaces undergoing resorption, and necessarily requires site-specific recruitment of mononucleated pre-osteoclasts originating from the bone marrow. However, the spatiotemporal mechanism coordinating recruitment and fusion is poorly investigated. Herein we identify a collagen/vascular network as a likely structure supporting this mechanism. We therefore used multiplex immunohistochemistry and electron microscopy on human iliac crest bone samples, in combination with functional assays performed in vitro with osteoclasts generated from healthy blood donors. First, we found that putative pre-osteoclasts are in close vicinity of a network of collagen fibers associated with vessels and bone remodeling compartment canopies. Based on 3D-reconstructions of serial sections, we propose that this network may serve as roads leading pre-osteoclasts to resorption sites, as reported for cell migration in other tissues. Importantly, almost all these bone marrow pre-osteoclasts, but only some osteoclasts, express the collagen receptor OSCAR, which is reported to induce fusion competence. Furthermore, differentiating osteoclasts cultured on collagen compared to mineral show higher fusion rates, higher expression of fusogenic cytokines, and a CD47 plasma membrane distribution pattern reported to be typical of a pre-fusion state-thus collectively supporting collagen-induced fusion competence. Finally, these in vitro assays show that collagen induces high cell mobility. The present data lead to a model where collagen fibers/vasculature support the coordination between traffic and fusion of pre-osteoclasts, by serving as a physical road and inducing fusion competence as well as cell mobility.
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Affiliation(s)
- Kent Søe
- Clinical Cell Biology, Department of Regional Health Research, Vejle Hospital - Lillebaelt Hospital, University of Southern Denmark, Beriderbakken 4, 7100, Vejle, Denmark.
- Clinical Cell Biology, Department of Pathology, Odense University Hospital - Department of Clinical Research, University of Southern Denmark, J. B. Winsløvs Vej 25, 1st floor, 5000, Odense C, Denmark.
| | - Thomas Levin Andersen
- Clinical Cell Biology, Department of Regional Health Research, Vejle Hospital - Lillebaelt Hospital, University of Southern Denmark, Beriderbakken 4, 7100, Vejle, Denmark.
- Clinical Cell Biology, Department of Pathology, Odense University Hospital - Department of Clinical Research, University of Southern Denmark, J. B. Winsløvs Vej 25, 1st floor, 5000, Odense C, Denmark.
| | - Maja Hinge
- Clinical Cell Biology, Department of Regional Health Research, Vejle Hospital - Lillebaelt Hospital, University of Southern Denmark, Beriderbakken 4, 7100, Vejle, Denmark
- Department of Internal Medicine, Section of Hematology, Vejle Hospital - Lillebaelt Hospital, Beriderbakken 4, 7100, Vejle, Denmark
| | - Lars Rolighed
- Breast and Endocrine Section, Department of Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Niels Marcussen
- Department of Pathology, Odense University Hospital, J. B. Winsløws Vej 15, 5000, Odense, Denmark
| | - Jean-Marie Delaisse
- Clinical Cell Biology, Department of Regional Health Research, Vejle Hospital - Lillebaelt Hospital, University of Southern Denmark, Beriderbakken 4, 7100, Vejle, Denmark
- Clinical Cell Biology, Department of Pathology, Odense University Hospital - Department of Clinical Research, University of Southern Denmark, J. B. Winsløvs Vej 25, 1st floor, 5000, Odense C, Denmark
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27
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Goel PN, Moharrer Y, Hebb JH, Egol AJ, Kaur G, Hankenson KD, Ahn J, Ashley JW. Suppression of Notch Signaling in Osteoclasts Improves Bone Regeneration and Healing. J Orthop Res 2019; 37:2089-2103. [PMID: 31166033 PMCID: PMC6739141 DOI: 10.1002/jor.24384] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/28/2019] [Indexed: 02/04/2023]
Abstract
Owing to the central role of osteoclasts in bone physiology and remodeling, manipulation of their maturation process provides a potential therapeutic strategy for treating bone diseases. To investigate this, we genetically inhibited the Notch signaling pathway in the myeloid lineage, which includes osteoclast precursors, using a dominant negative form of MAML (dnMAML) that inhibits the transcriptional complex required for downstream Notch signaling. Osteoclasts derived from dnMAML mice showed no significant differences in early osteoclastic gene expression compared to the wild type. Further, these demonstrated significantly lowered resorption activity using bone surfaces while retaining their osteoblast stimulating ability using ex vivo techniques. Using in vivo approaches, we detected significantly higher bone formation rates and osteoblast gene expression in dnMAML cohorts. Further, these mice exhibited increased bone/tissue mineral density compared to wild type and larger bony calluses in later stages of fracture healing. These observations suggest that therapeutic suppression of osteoclast Notch signaling could reduce, but not eliminate, osteoclastic resorption without suppression of restorative bone remodeling and, therefore, presents a balanced paradigm for increasing bone formation, regeneration, and healing. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2089-2103, 2019.
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Affiliation(s)
- Peeyush N Goel
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA,Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - Yasaman Moharrer
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA,Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - John H Hebb
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA,Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA,Georgetown University School of Medicine, Washington D.C
| | - Alexander J Egol
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA,Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | | | | | - Jaimo Ahn
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA,Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA,Co-corresponding Author: Jaimo Ahn, MD, PhD, FACS, FAOA, Advisory Dean, MSTP Steering Committee, Perelman School of Medicine, Co-Director, Orthopaedic Trauma, University of Pennsylvania Health System, Perelman School of Medicine, University of Pennsylvania, Investigator, Translational Musculoskeletal Research Center, Philadelphia Veterans Affairs Medical Center, 3737 Market Street, Floor 6, Philadelphia, PA-19104, Phone # +1 (215)-662-3340, Fax # +1 (215)-349-5890,
| | - Jason W Ashley
- Eastern Washington University, Cheney, WA,Corresponding Author: Jason Waid Ashley, PhD, Assistant Professor, Biology Department, 526 5th Street, SCI236, Eastern Washington University, Cheney, WA 99004, Phone # +1(509)-359-4665,
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28
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Coudert AE, Redelsperger F, Chabbi-Achengli Y, Vernochet C, Marty C, Decrouy X, Heidmann T, de Vernejoul MC, Dupressoir A. Role of the captured retroviral envelope syncytin-B gene in the fusion of osteoclast and giant cell precursors and in bone resorption, analyzed ex vivo and in vivo in syncytin-B knockout mice. Bone Rep 2019; 11:100214. [PMID: 31360740 PMCID: PMC6637224 DOI: 10.1016/j.bonr.2019.100214] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 07/09/2019] [Indexed: 12/23/2022] Open
Abstract
Syncytin-A and -B are envelope genes of retroviral origin that have been captured in evolution for a role in placentation. They trigger cell-cell fusion and were shown to be essential for the formation of the syncytiotrophoblast layer during mouse placenta formation. Syncytin-A and -B expression has been described in other tissues and their highly fusogenic properties suggested that they might be involved in the fusion of other cell types. Here, taking advantage of mice knocked out for syncytin-B, SynB-/- mice, we investigated the potential role of syncytin-B in the fusion of cells from the monocyte/macrophage lineage into multinucleated osteoclasts (OCs) -in bone- or multinucleated giant cells -in soft tissues. In ex vivo experiments, a significant reduction in fusion index and in the number of multinucleated OCs and giant cells was observed as soon as Day3 in SynB-/- as compared to wild-type cell cultures. Interestingly, the number of nuclei per multinucleated OC or giant cell remained unchanged. These results, together with the demonstration that syncytin-B expression is maximal in the first 2 days of OC differentiation, argue for syncytin-B playing a role in the fusion of OC and giant cell mononucleated precursors, at initial stages. Finally, ex vivo, the observed reduction in multinucleated OC number had no impact on the expression of OC differentiation markers, and a dentin resorption assay did not evidence any difference in the osteoclastic resorption activity, suggesting that syncytin-B is not required for OC activity. In vivo, syncytin-B was found to be expressed in the periosteum of embryos at embryonic day 16.5, where TRAP-positive cells were observed. Yet, in adults, no significant reduction in OC number or alteration in bone phenotype was observed in SynB-/- mice. In addition, SynB-/- mice did not show any change in the number of foreign body giant cells (FBGCs) that formed in response to implantation of foreign material, as compared to wild-type mice. Altogether the results suggest that in addition to its essential role in placenta formation, syncytin-B plays a role in OCs and macrophage fusion; yet it is not essential in vivo for OC and FBGC formation, or maintenance of bone homeostasis, at least under the conditions tested.
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Affiliation(s)
- Amélie E Coudert
- BIOSCAR, Unité Mixte de Recherche 1132, Institut National de la Santé et de la Recherche Médicale, Hôpital Lariboisière, Paris 75010, France.,Laboratoire de Physiopathologie Orale Moléculaire, INSERM U1138, Centre de recherche des Cordeliers, UFR d'Odontologie Garancire, Université Paris Diderot, Paris 75006, France
| | - François Redelsperger
- Unité Physiologie et Pathologie Moléculaires des Rétrovirus Endogènes et Infectieux, Unité Mixte de Recherche 9196, Centre National de la Recherche Scientifique, Gustave Roussy, Villejuif, 94805, and Université Paris-Sud, Orsay, 91405, France
| | - Yasmine Chabbi-Achengli
- BIOSCAR, Unité Mixte de Recherche 1132, Institut National de la Santé et de la Recherche Médicale, Hôpital Lariboisière, Paris 75010, France
| | - Cécile Vernochet
- Unité Physiologie et Pathologie Moléculaires des Rétrovirus Endogènes et Infectieux, Unité Mixte de Recherche 9196, Centre National de la Recherche Scientifique, Gustave Roussy, Villejuif, 94805, and Université Paris-Sud, Orsay, 91405, France
| | - Caroline Marty
- BIOSCAR, Unité Mixte de Recherche 1132, Institut National de la Santé et de la Recherche Médicale, Hôpital Lariboisière, Paris 75010, France
| | - Xavier Decrouy
- Inserm, U955, Plateforme d'imagerie, Créteil, 9400, France and Université Paris Est, Faculté de médecine, Créteil, 94000, France
| | - Thierry Heidmann
- Unité Physiologie et Pathologie Moléculaires des Rétrovirus Endogènes et Infectieux, Unité Mixte de Recherche 9196, Centre National de la Recherche Scientifique, Gustave Roussy, Villejuif, 94805, and Université Paris-Sud, Orsay, 91405, France
| | - Marie-Christine de Vernejoul
- BIOSCAR, Unité Mixte de Recherche 1132, Institut National de la Santé et de la Recherche Médicale, Hôpital Lariboisière, Paris 75010, France
| | - Anne Dupressoir
- Unité Physiologie et Pathologie Moléculaires des Rétrovirus Endogènes et Infectieux, Unité Mixte de Recherche 9196, Centre National de la Recherche Scientifique, Gustave Roussy, Villejuif, 94805, and Université Paris-Sud, Orsay, 91405, France
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29
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Faust JJ, Balabiyev A, Heddleston JM, Podolnikova NP, Baluch DP, Chew TL, Ugarova TP. An actin-based protrusion originating from a podosome-enriched region initiates macrophage fusion. Mol Biol Cell 2019; 30:2254-2267. [PMID: 31242090 PMCID: PMC6743464 DOI: 10.1091/mbc.e19-01-0009] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Macrophage fusion resulting in the formation of multinucleated giant cells occurs in a variety of chronic inflammatory diseases, yet the mechanism responsible for initiating this process is unknown. Here, we used live cell imaging to show that actin-based protrusions at the leading edge initiate macrophage fusion. Phase-contrast video microscopy demonstrated that in the majority of events, short protrusions (∼3 µm) between two closely apposed cells initiated fusion, but occasionally we observed long protrusions (∼12 µm). Using macrophages isolated from LifeAct mice and imaging with lattice light sheet microscopy, we further found that fusion-competent protrusions formed at sites enriched in podosomes. Inducing fusion in mixed populations of GFP- and mRFP-LifeAct macrophages showed rapid spatial overlap between GFP and RFP signal at the site of fusion. Cytochalasin B strongly reduced fusion and when rare fusion events occurred, protrusions were not observed. Fusion of macrophages deficient in Wiskott-Aldrich syndrome protein and Cdc42, key molecules involved in the formation of actin-based protrusions and podosomes, was also impaired both in vitro and in vivo. Finally, inhibiting the activity of the Arp2/3 complex decreased fusion and podosome formation. Together these data suggest that an actin-based protrusion formed at the leading edge initiates macrophage fusion.
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Affiliation(s)
- James J Faust
- School of Life Sciences, Arizona State University, Tempe, AZ 85287
| | - Arnat Balabiyev
- School of Life Sciences, Arizona State University, Tempe, AZ 85287
| | - John M Heddleston
- Advanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA 20147
| | | | - D Page Baluch
- School of Life Sciences, Arizona State University, Tempe, AZ 85287
| | - Teng-Leong Chew
- Advanced Imaging Center, HHMI Janelia Research Campus, Ashburn, VA 20147
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30
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Jaber FA, Khan NM, Ansari MY, Al-Adlaan AA, Hussein NJ, Safadi FF. Autophagy plays an essential role in bone homeostasis. J Cell Physiol 2019; 234:12105-12115. [PMID: 30820954 DOI: 10.1002/jcp.27071] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 06/29/2018] [Indexed: 12/20/2022]
Abstract
Autophagy is very critical for multiple cellular processes. Autophagy plays a critical role in bone cell differentiation and function.
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Affiliation(s)
- Fatima A Jaber
- Department of Biology, King Abdulaziz University, Jeddah, Saudi Arabia.,Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED) School of Medicine, Rootstown, Ohio.,School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Nazir M Khan
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED) School of Medicine, Rootstown, Ohio
| | - Mohammad Y Ansari
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED) School of Medicine, Rootstown, Ohio
| | - Asaad A Al-Adlaan
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED) School of Medicine, Rootstown, Ohio.,School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Nazar J Hussein
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED) School of Medicine, Rootstown, Ohio.,School of Biomedical Sciences, Kent State University, Kent, Ohio
| | - Fayez F Safadi
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED) School of Medicine, Rootstown, Ohio.,School of Biomedical Sciences, Kent State University, Kent, Ohio.,Department of Pharmaceutical Sciences, College of Pharmacy, Northeast Ohio Medical University, Rootstown, Ohio.,Department of Orthopedic Surgery, SUMMA Health System, Akron, Ohio.,Rebecca D. Considine Research Institute Akron Children's Hospital, Akron, Ohio
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31
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Myosins in Osteoclast Formation and Function. Biomolecules 2018; 8:biom8040157. [PMID: 30467281 PMCID: PMC6317158 DOI: 10.3390/biom8040157] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 11/16/2018] [Accepted: 11/19/2018] [Indexed: 01/16/2023] Open
Abstract
Skeletal quantity and quality are determined by processes of bone modeling and remodeling, which are undertaken by cells that build and resorb bone as they respond to mechanical, hormonal, and other external and internal signals. As the sole bone resorptive cell type, osteoclasts possess a remarkably dynamic actin cytoskeleton that drives their function in this enterprise. Actin rearrangements guide osteoclasts’ capacity for precursor fusion during differentiation, for migration across bone surfaces and sensing of their composition, and for generation of unique actin superstructures required for the resorptive process. In this regard, it is not surprising that myosins, the superfamily of actin-based motor proteins, play key roles in osteoclast physiology. This review briefly summarizes current knowledge of the osteoclast actin cytoskeleton and describes myosins’ roles in osteoclast differentiation, migration, and actin superstructure patterning.
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32
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Zhao W, Shen G, Ren H, Liang D, Yu X, Zhang Z, Huang J, Qiu T, Tang J, Shang Q, Yu P, Wu Z, Jiang X. Therapeutic potential of microRNAs in osteoporosis function by regulating the biology of cells related to bone homeostasis. J Cell Physiol 2018; 233:9191-9208. [PMID: 30078225 DOI: 10.1002/jcp.26939] [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: 02/06/2018] [Accepted: 06/13/2018] [Indexed: 12/13/2022]
Abstract
MicroRNAs (miRNAs) are novel regulatory factors that play important roles in numerous cellular processes through the posttranscriptional regulation of gene expression. Recently, deregulation of the miRNA-mediated mechanism has emerged as an important pathological factor in osteoporosis. However, a detailed molecular mechanism between miRNAs and osteoporosis is still not available. In this review, the roles of miRNAs in the regulation of cells related to bone homeostasis as well as miRNAs that deregulate in human or animal are discussed. Moreover, the miRNAs that act as clusters in the biology of cells in the bone microenvironment and the difference of some important miRNAs for bone homeostasis between bone and other organs are mentioned. Overall, miRNAs that contribute to the pathogenesis of osteoporosis and their therapeutic potential are considered.
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Affiliation(s)
- Wenhua Zhao
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Gengyang Shen
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Hui Ren
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - De Liang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiang Yu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhida Zhang
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jinjing Huang
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Ting Qiu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jingjing Tang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Qi Shang
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Peiyuan Yu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zixian Wu
- Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiaobing Jiang
- Department of Spinal Surgery, The First Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.,Laboratory Affiliated to National Key Discipline of Orthopaedic and Traumatology of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China
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33
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Pata M, Vacher J. Ostm1 Bifunctional Roles in Osteoclast Maturation: Insights From a Mouse Model Mimicking a Human OSTM1 Mutation. J Bone Miner Res 2018; 33:888-898. [PMID: 29297601 DOI: 10.1002/jbmr.3378] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/21/2017] [Accepted: 12/27/2017] [Indexed: 11/12/2022]
Abstract
Ostm1 mutations are responsible for the most severe form of osteopetrosis in human and mice. To gain insight into Ostm1 cellular functions, we engineered a conditional in-frame deletion of the Ostm1 transmembrane domain and generated the first Ostm1 mouse model with a human mutation. Systemic targeting of Ostm1 loss of transmembrane domain produced osteopetrosis, as in the null Ostm1 gl/gl mouse. Significantly, conditional osteoclast targeting of Ostm1 resulted in similar osteopetrosis, thereby demonstrating that the intrinsic Ostm1 osteoclast deficiency is solely responsible for the mouse phenotype. Our analysis showed oversized osteoclasts with enhanced multinucleation associated with stimulation of intracellular calcium levels, of Nfatc1 nuclear re-localization, and of specific downstream Nfatc1 target genes, providing compelling evidence that Ostm1 is a negative regulator of preosteoclast fusion. Moreover, mature OCs with Ostm1 loss of transmembrane domain show appropriate levels of intracellular acidification but an altered distribution pattern, highlighting misregulation of endolysosome localization and dispersion. Consistently, the hydrolases tartrate-resistant acid phosphatase (TRAP) and cathepsin K (Ctsk) normally produced are sequestered within the osteoclasts and are not extracellularly secreted. These studies defined bifunctional roles for Ostm1 as a major regulator of preosteoclast cytoskeletal rearrangements toward cell multinucleation and of mature osteoclast intracellular lysosomal trafficking and exocytosis mechanism, both of which are essential for bone resorption. Importantly, these Ostm1 molecular and regulatory functions could serve as preclinical targets in this mouse model toward osteoclastogenic pathologies as osteoporosis and inflammation-induced bone loss. © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Monica Pata
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada
| | - Jean Vacher
- Institut de Recherches Cliniques de Montréal (IRCM), Montréal, Québec, Canada.,Département de Médecine, Université de Montréal, Montréal, Québec, Canada.,Department of Medicine, Division of Experimental Medicine, McGill University, Montréal, Québec, Canada
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Reinke DC, Starczak Y, Kogawa M, Barratt KR, Morris HA, Anderson PH, Atkins GJ. Evidence for altered osteoclastogenesis in splenocyte cultures from VDR knockout mice. J Steroid Biochem Mol Biol 2018; 177:96-102. [PMID: 28765041 DOI: 10.1016/j.jsbmb.2017.07.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 12/22/2022]
Abstract
The indirect action of 1α,25(OH)2-vitamin-D3 (1,25D) on the osteoclast through stromal signalling is well established. The role of vitamin D in osteoclasts through direct 1,25D-VDR signalling is less well known. We showed previously that local 1,25D synthesis in osteoclasts modified osteoclastogenesis and osteoclastic resorptive activity. In this study, we hypothesised that osteoclasts lacking VDR expression would display an enhanced resorptive capacity due to the loss of 1,25D signalling. Splenocytes were cultured under osteoclast-differentiating conditions from mice with global deletion of the Vdr gene (VDRKO) and this was compared with age-matched wild-type littermate controls (WT). In VDRKO cultures, osteoclastogenesis was reduced, as indicated by fewer TRAP-positive multinucleated cells at all time points measured (p<0.05) compared to WT levels. However, VDRKO osteoclasts demonstrated greater resorption on a per cell basis than their WT counterparts. VDRKO cultures expressed greatly increased c-Fos mRNA compared to WT. In addition, the ratio of expression of the pro-apoptotic gene Bax to the pro-survival gene Bcl-2 was decreased in VDRKO cultures, implying that these osteoclasts may survive longer than WT osteoclasts. Our data indicate abnormal osteoclastogenesis due to the absence of Vdr expression, consistent with direct effects of vitamin D signalling being important for regulating the maturation and resorptive activities of osteoclasts.
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Affiliation(s)
- Daniel C Reinke
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, University of Adelaide, Australia
| | - Yolandi Starczak
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, University of Adelaide, Australia; School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5005, Australia
| | - Masakazu Kogawa
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, University of Adelaide, Australia
| | - Kate R Barratt
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5005, Australia
| | - Howard A Morris
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5005, Australia
| | - Paul H Anderson
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5005, Australia
| | - Gerald J Atkins
- Biomedical Orthopaedic Research Group, Centre for Orthopaedic & Trauma Research, University of Adelaide, Australia.
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Abstract
Cell-cell fusion is a key stage in development and maintenance of multinucleated cells that resorb bones and form our skeletal muscles and placenta. Here, we focus on osteoclast formation to suggest new ways of unbiased presentation of cell fusion at given conditions that combine empirical cumulative distribution function for the sizes of multinucleated cells with the total number of cell-cell fusion events, which generate these cells.
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36
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Guterman-Ram G, Pesic M, Orenbuch A, Czeiger T, Aflalo A, Levaot N. Dual-specificity tyrosine phosphorylation-regulated kinase 2 regulates osteoclast fusion in a cell heterotypic manner. J Cell Physiol 2018; 233:617-629. [PMID: 28332708 DOI: 10.1002/jcp.25922] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 03/21/2017] [Indexed: 12/14/2022]
Abstract
Monocyte fusion into osteoclasts, bone resorbing cells, plays a key role in bone remodeling and homeostasis; therefore, aberrant cell fusion may be involved in a variety of debilitating bone diseases. Research in the last decade has led to the discovery of genes that regulate osteoclast fusion, but the basic molecular and cellular regulatory mechanisms underlying the fusion process are not completely understood. Here, we reveal a role for Dyrk2 in osteoclast fusion. We demonstrate that Dyrk2 down regulation promotes osteoclast fusion, whereas its overexpression inhibits fusion. Moreover, Dyrk2 also promotes the fusion of foreign-body giant cells, indicating that Dyrk2 plays a more general role in cell fusion. In an earlier study, we showed that fusion is a cell heterotypic process initiated by fusion-founder cells that fuse to fusion-follower cells, the latter of which are unable to initiate fusion. Here, we show that Dyrk2 limits the expansion of multinucleated founder cells through the suppression of the fusion competency of follower cells.
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Affiliation(s)
- Gali Guterman-Ram
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Milena Pesic
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ayelet Orenbuch
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Tal Czeiger
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Anastasia Aflalo
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Noam Levaot
- Department of Physiology and Cell Biology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Faculty of Health Sciences, Ben-Gurion University of the Negev, Regenerative Medicine and Stem Cell (RMSC) Research Center, Beer-Sheva, Israel
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37
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Horn V, Triantafyllopoulou A. DNA damage signaling and polyploid macrophages in chronic inflammation. Curr Opin Immunol 2017; 50:55-63. [PMID: 29202328 DOI: 10.1016/j.coi.2017.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 10/30/2017] [Accepted: 11/17/2017] [Indexed: 01/01/2023]
Abstract
Whole genome duplications, an important step in cancer development, also occur in the macrophage lineage in disease: large multinucleated macrophages found within compact, ordered aggregates of immune cells, called granulomas, are a well-known histologic entity. Very recent work suggests that granuloma macrophages remarkably acquire epithelial cell features and the genotoxic stress response instructs granuloma macrophage genome duplications, suggesting that granuloma macrophages and pre-malignant epithelial cells may share common mechanisms of adaptation to chronic genotoxic stress. Exploring these mechanisms is key for a better understanding of the pathogenesis of chronic inflammatory diseases. Here we review the mechanisms of macrophage polyploidization, the role of DNA damage signaling in this process and the function of polyploid macrophages, with a focus on chronic inflammation.
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Affiliation(s)
- Veronika Horn
- Department of Rheumatology and Clinical Immunology, Charité University Medical Center, D-10117 Berlin, Germany; Department of Rheumatology and Clinical Immunology, University Medical Center Freiburg, D-79106 Freiburg, Germany
| | - Antigoni Triantafyllopoulou
- Department of Rheumatology and Clinical Immunology, Charité University Medical Center, D-10117 Berlin, Germany; Department of Rheumatology and Clinical Immunology, University Medical Center Freiburg, D-79106 Freiburg, Germany; German Rheumatism Research Center, A Leibniz Institute, D-10117 Berlin, Germany; Institute of Microbiology, Charité University Medical Center, D-12203 Berlin, Germany.
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38
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Takito J, Otsuka H, Inoue S, Kawashima T, Nakamura M. Symmetrical retrograde actin flow in the actin fusion structure is involved in osteoclast fusion. Biol Open 2017; 6:1104-1114. [PMID: 28711870 PMCID: PMC5550915 DOI: 10.1242/bio.025460] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The aim of this study was to elucidate the role of the zipper-like structure (ZLS), a podosome-related structure that transiently appears at the cell contact zone, in osteoclast fusion. Live-cell imaging of osteoclasts derived from RAW264.7 cells transfected with EGFP-actin revealed consistent symmetrical retrograde actin flow in the ZLS, but not in the podosome cluster, the podosome ring or the podosome belt. Confocal imaging showed that the distributions of F-actin, vinculin, paxillin and zyxin in the ZLS were different from those in the podosome belt. Thick actin filament bundles running outside the ZLS appeared to recruit non-muscle myosin IIA. The F-actin-rich domain of the ZLS contained actin-related protein 2/3 complex (Arp2/3). Inhibition of Arp2/3 activity disorganized the ZLS, disrupted actin flow, deteriorated cell-cell adhesion and inhibited osteoclast hypermultinucleation. In contrast, ML-7, an inhibitor of myosin light chain kinase, had little effect on the structure of ZLS and promoted osteoclast hypermultinucleation. These results reveal a link between actin flow in the ZLS and osteoclast fusion. Osteoclast fusion was promoted by branched actin elongation and negatively regulated by actomyosin contraction. Summary: Multinucleated osteoclasts form a podosome-derived fusion structure during cell fusion. Juxtaposition of fusion partner cells is probably maintained via force generated by symmetrical retrograde actin flow in the fusion structure.
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Affiliation(s)
- Jiro Takito
- Department of Oral Anatomy and Developmental Biology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan
| | - Hirotada Otsuka
- Department of Oral Anatomy and Developmental Biology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan
| | - Satoshi Inoue
- Department of Oral Anatomy and Developmental Biology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan
| | - Tsubasa Kawashima
- Department of Paediatric Dentistry, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan
| | - Masanori Nakamura
- Department of Oral Anatomy and Developmental Biology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555, Japan
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Chiu YH, Schwarz E, Li D, Xu Y, Sheu TR, Li J, de Mesy Bentley KL, Feng C, Wang B, Wang JC, Albertorio-Saez L, Wood R, Kim M, Wang W, Ritchlin CT. Dendritic Cell-Specific Transmembrane Protein (DC-STAMP) Regulates Osteoclast Differentiation via the Ca 2+ /NFATc1 Axis. J Cell Physiol 2017; 232:2538-2549. [PMID: 27723141 DOI: 10.1002/jcp.25638] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 10/07/2016] [Indexed: 12/16/2022]
Abstract
DC-STAMP is a multi-pass transmembrane protein essential for cell-cell fusion between osteoclast precursors during osteoclast (OC) development. DC-STAMP-/- mice have mild osteopetrosis and form mononuclear cells with limited resorption capacity. The identification of an Immunoreceptor Tyrosine-based Inhibitory Motif (ITIM) on the cytoplasmic tail of DC-STAMP suggested a potential signaling function. The absence of a known DC-STAMP ligand, however, has hindered the elucidation of downstream signaling pathways. To address this problem, we engineered a light-activatable DC-STAMP chimeric molecule in which light exposure mimics ligand engagement that can be traced by downstream Ca2+ signaling. Deletion of the cytoplasmic ITIM resulted in a significant elevation in the amplitude and duration of intracellular Ca2+ flux. Decreased NFATc1 expression in DC-STAMP-/- cells was restored by DC-STAMP over-expression. Multiple biological phenotypes including cell-cell fusion, bone erosion, cell mobility, DC-STAMP cell surface distribution, and NFATc1 nuclear translocation were altered by deletion of the ITIM and adjacent amino acids. In contrast, mutations on each of the tyrosine residues surrounding the ITIM showed no effect on DC-STAMP function. Collectively, our results suggest that the ITIM on DC-STAMP is a functional motif that regulates osteoclast differentiation through the NFATc1/Ca2+ axis. J. Cell. Physiol. 232: 2538-2549, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ya-Hui Chiu
- Division of Allergy/Immunology and Rheumatology, The University of Rochester, Rochester, New York
| | - Edward Schwarz
- The Center for Musculoskeletal Research, The University of Rochester, Rochester, New York
| | - Dongge Li
- Division of Allergy/Immunology and Rheumatology, The University of Rochester, Rochester, New York
| | - Yuexin Xu
- Microbiology and Immunology, The University of Rochester, Rochester, New York
| | - Tzong-Ren Sheu
- The Center for Musculoskeletal Research, The University of Rochester, Rochester, New York
| | - Jinbo Li
- Pathology and Laboratory Medicine, School of Medicine and Dentistry, The University of Rochester, Rochester, New York
| | - Karen L de Mesy Bentley
- Microbiology and Immunology, The University of Rochester, Rochester, New York.,Pathology and Laboratory Medicine, School of Medicine and Dentistry, The University of Rochester, Rochester, New York
| | - Changyong Feng
- Biostatistic, The University of Rochester, Rochester, New York
| | - Baoli Wang
- Hormones and Development, Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin, China
| | - Jhih-Cheng Wang
- Institution of Biomedical Engineering, National Cheng Kung University, Tainan City, Taiwan
| | - Liz Albertorio-Saez
- Division of Allergy/Immunology and Rheumatology, The University of Rochester, Rochester, New York
| | - Ronald Wood
- OB/GYN, Urology, Neuroscience, The University of Rochester, Rochester, New York
| | - Minsoo Kim
- Microbiology and Immunology, The University of Rochester, Rochester, New York
| | - Wensheng Wang
- 1st Affiliated Hospital, Xinxiang Medical University, Weihui City, Henan Province, China
| | - Christopher T Ritchlin
- Division of Allergy/Immunology and Rheumatology, The University of Rochester, Rochester, New York
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40
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Zito F, Lampiasi N, Kireev I, Russo R. United we stand: Adhesion and molecular mechanisms driving cell fusion across species. Eur J Cell Biol 2016; 95:552-562. [DOI: 10.1016/j.ejcb.2016.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 09/13/2016] [Accepted: 09/19/2016] [Indexed: 01/14/2023] Open
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41
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Møller AMJ, Delaissé JM, Søe K. Osteoclast Fusion: Time-Lapse Reveals Involvement of CD47 and Syncytin-1 at Different Stages of Nuclearity. J Cell Physiol 2016; 232:1396-1403. [PMID: 27714815 PMCID: PMC6221100 DOI: 10.1002/jcp.25633] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 10/05/2016] [Indexed: 12/13/2022]
Abstract
Investigations addressing the molecular keys of osteoclast fusion are primarily based on end-point analyses. No matter if investigations are performed in vivo or in vitro the impact of a given factor is predominantly analyzed by counting the number of multi-nucleated cells, the number of nuclei per multinucleated cell or TRAcP activity. But end-point analyses do not show how the fusion came about. This would not be a problem if fusion of osteoclasts was a random process and occurred by the same molecular mechanism from beginning to end. However, we and others have in the recent period published data suggesting that fusion partners may specifically select each other and that heterogeneity between the partners seems to play a role. Therefore, we set out to directly test the hypothesis that fusion factors have a heterogenic involvement at different stages of nuclearity. Therefore, we have analyzed individual fusion events using time-lapse and antagonists of CD47 and syncytin-1. All time-lapse recordings have been studied by two independent observers. A total of 1808 fusion events were analyzed. The present study shows that CD47 and syncytin-1 have different roles in osteoclast fusion depending on the nuclearity of fusion partners. While CD47 promotes cell fusions involving mono-nucleated pre-osteoclasts, syncytin-1 promotes fusion of two multi-nucleated osteoclasts, but also reduces the number of fusions between mono-nucleated pre-osteoclasts. Furthermore, CD47 seems to mediate fusion mostly through broad contact surfaces between the partners' cell membrane while syncytin-1 mediate fusion through phagocytic-cup like structure. J. Cell. Physiol. 232: 1396-1403, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Anaïs Marie Julie Møller
- Department of Clinical Cell Biology, Vejle Hospital/Lillebaelt Hospital, Institute of Regional Health Research, University of Southern Denmark, Vejle, Denmark
| | - Jean-Marie Delaissé
- Department of Clinical Cell Biology, Vejle Hospital/Lillebaelt Hospital, Institute of Regional Health Research, University of Southern Denmark, Vejle, Denmark
| | - Kent Søe
- Department of Clinical Cell Biology, Vejle Hospital/Lillebaelt Hospital, Institute of Regional Health Research, University of Southern Denmark, Vejle, Denmark
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42
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Chiu YH, Ritchlin CT. DC-STAMP: A Key Regulator in Osteoclast Differentiation. J Cell Physiol 2016; 231:2402-7. [PMID: 27018136 DOI: 10.1002/jcp.25389] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 03/24/2016] [Indexed: 01/09/2023]
Abstract
Osteoimmunology research is a new emerging research field that investigates the links between the bone and immune responses. Results from osteoimmunology studies suggest that bone is not only an essential component of the musculoskeletal system, but is also actively involved in immune regulation. Many important factors involved in immune regulation also participate in bone homeostasis. Bone homeostasis is achieved by a coordinated action between bone-synthesizing osteoblasts and bone-degrading osteoclasts. An imbalanced action between osteoblasts and osteoclasts often results in pathological bone diseases: osteoporosis is caused by an excessive osteoclast activity, whereas osteopetrosis results from an increased osteoblast activity. This review focuses on dendritic cell-specific transmembrane protein (DC-STAMP), an important protein currently considered as a master regulator of osteoclastogenesis. Of clinical relevance, the frequency of circulating DC-STAMP+ cells is elevated during the pathogenesis of psoriatic diseases. Intriguingly, recent results suggest that DC-STAMP also plays an imperative role in bone homeostasis by regulating the differentiation of both osteoclasts and osteoblasts. This article summarizes our current knowledge on DC-STAMP by focusing on its interacting proteins, its regulation on osteoclastogenesis-related genes, its possible involvement in immunoreceptor tyrosine-based inhibitory motif (ITIM)-mediated signaling cascade, and its potential of developing therapeutics for clinical applications. J. Cell. Physiol. 231: 2402-2407, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ya-Hui Chiu
- Division of Allergy, Immunology and Rheumatology, School of Medicine, University of Rochester, Rochester, New York
| | - Christopher T Ritchlin
- Division of Allergy, Immunology and Rheumatology, School of Medicine, University of Rochester, Rochester, New York
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43
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Fiorino C, Harrison RE. E-cadherin is important for cell differentiation during osteoclastogenesis. Bone 2016; 86:106-18. [PMID: 26959175 DOI: 10.1016/j.bone.2016.03.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 01/29/2016] [Accepted: 03/04/2016] [Indexed: 01/05/2023]
Abstract
E-cadherin, a protein responsible for intercellular adhesion between epithelial cells, is also expressed in the monocyte/macrophage lineage. In this study we have explored the involvement of E-cadherin during receptor activator of nuclear factor-κB ligand (RANKL)-stimulated osteoclast differentiation. Osteoclastogenesis involves a period of precursor expansion followed by multiple fusion events to generate a multinuclear osteoclast that is capable of bone resorption. We asked whether E-cadherin participated in early precursor interactions and recognition or was a component of the osteoclast fusion machinery. Here, we show that endogenous E-cadherin expression is the highest during early stages of osteoclast differentiation, with surface expression visible on small precursor cells (fewer than four nuclei per cell) in both RAW 264.7 cells and primary macrophages. Blocking E-cadherin function with neutralizing antibodies prior to the onset of fusion delayed the expression of TRAP, Cathepsin K, DC-STAMP and NFATc1 and significantly diminished multinucleated osteoclast formation. Conversely, E-cadherin-GFP overexpressing macrophages displayed earlier NFATc1 nuclear translocation along with faster formation of multinucleated osteoclasts compared to control macrophages. Through live imaging we identified that disrupting E-cadherin function prolonged the proliferative phase of the precursor population while concomitantly decreasing the proportion of migrating precursors. The lamellipodium and polarized membrane extensions appeared to be the principal sites of fusion, indicating precursor migration was a critical factor contributing to osteoclast fusion. These findings demonstrate that E-cadherin-mediated cell-cell contacts can modulate osteoclast-specific gene expression and prompt differentiating osteoclast precursors toward migratory and fusion activities.
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Affiliation(s)
- Cara Fiorino
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario M1C 1A4, Canada; Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - Rene E Harrison
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario M1C 1A4, Canada; Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada.
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44
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Role of actin filaments in fusopod formation and osteoclastogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1715-24. [DOI: 10.1016/j.bbamcr.2015.04.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/19/2015] [Accepted: 04/06/2015] [Indexed: 12/16/2022]
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45
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Witwicka H, Hwang SY, Reyes-Gutierrez P, Jia H, Odgren PE, Donahue LR, Birnbaum MJ, Odgren PR. Studies of OC-STAMP in Osteoclast Fusion: A New Knockout Mouse Model, Rescue of Cell Fusion, and Transmembrane Topology. PLoS One 2015; 10:e0128275. [PMID: 26042409 PMCID: PMC4456411 DOI: 10.1371/journal.pone.0128275] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 04/23/2015] [Indexed: 11/29/2022] Open
Abstract
The fusion of monocyte/macrophage lineage cells into fully active, multinucleated, bone resorbing osteoclasts is a complex cell biological phenomenon that utilizes specialized proteins. OC-STAMP, a multi-pass transmembrane protein, has been shown to be required for pre-osteoclast fusion and for optimal bone resorption activity. A previously reported knockout mouse model had only mononuclear osteoclasts with markedly reduced resorption activity in vitro, but with paradoxically normal skeletal micro-CT parameters. To further explore this and related questions, we used mouse ES cells carrying a gene trap allele to generate a second OC-STAMP null mouse strain. Bone histology showed overall normal bone form with large numbers of TRAP-positive, mononuclear osteoclasts. Micro-CT parameters were not significantly different between knockout and wild type mice at 2 or 6 weeks old. At 6 weeks, metaphyseal TRAP-positive areas were lower and mean size of the areas were smaller in knockout femora, but bone turnover markers in serum were normal. Bone marrow mononuclear cells became TRAP-positive when cultured with CSF-1 and RANKL, but they did not fuse. Expression levels of other osteoclast markers, such as cathepsin K, carbonic anhydrase II, and NFATc1, were not significantly different compared to wild type. Actin rings were present, but small, and pit assays showed a 3.5-fold decrease in area resorbed. Restoring OC-STAMP in knockout cells by lentiviral transduction rescued fusion and resorption. N- and C-termini of OC-STAMP were intracellular, and a predicted glycosylation site was shown to be utilized and to lie on an extracellular loop. The site is conserved in all terrestrial vertebrates and appears to be required for protein stability, but not for fusion. Based on this and other results, we present a topological model of OC-STAMP as a 6-transmembrane domain protein. We also contrast the osteoclast-specific roles of OC- and DC-STAMP with more generalized cell fusion mechanisms.
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Affiliation(s)
- Hanna Witwicka
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Sung-Yong Hwang
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Pablo Reyes-Gutierrez
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Hong Jia
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Paul E. Odgren
- Parallax Pictures, Princeton, MA, United States of America
| | - Leah Rae Donahue
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - Mark J. Birnbaum
- Department of Biology, Merrimack College, North Andover, MA, United States of America
| | - Paul R. Odgren
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
- * E-mail:
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