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Mayer A, McLaughlin G, Gladfelter A, Glass NL, Mela A, Roper M. Syncytial Assembly Lines: Consequences of Multinucleate Cellular Compartments for Fungal Protein Synthesis. Results Probl Cell Differ 2024; 71:159-183. [PMID: 37996678 DOI: 10.1007/978-3-031-37936-9_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2023]
Abstract
Fast growth and prodigious cellular outputs make fungi powerful tools in biotechnology. Recent modeling work has exposed efficiency gains associated with dividing the labor of transcription over multiple nuclei, and experimental innovations are opening new windows on the capacities and adaptations that allow nuclei to behave autonomously or in coordination while sharing a single, common cytoplasm. Although the motivation of our review is to motivate and connect recent work toward a greater understanding of fungal factories, we use the analogy of the assembly line as an organizing idea for studying coordinated gene expression, generally.
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Affiliation(s)
- Alex Mayer
- Department of Mathematics, University of California Los Angeles, Los Angeles, CA, USA
| | - Grace McLaughlin
- Department of Cell Biology, Duke University, Durham, NC, USA
- Department of Biology, University of North Carolina Chapel Hill, Chapel Hill, NC, USA
| | - Amy Gladfelter
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - N Louise Glass
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, USA
| | - Alexander Mela
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA, USA
| | - Marcus Roper
- Department of Mathematics, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Computational Medicine, University of California Los Angeles, Los Angeles, CA, USA.
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2
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Gambari L, Grigolo B, Grassi F. Dietary organosulfur compounds: Emerging players in the regulation of bone homeostasis by plant-derived molecules. Front Endocrinol (Lausanne) 2022; 13:937956. [PMID: 36187121 PMCID: PMC9521401 DOI: 10.3389/fendo.2022.937956] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 08/23/2022] [Indexed: 11/13/2022] Open
Abstract
The progressive decline of bone mass and the deterioration of bone microarchitecture are hallmarks of the bone aging. The resulting increase in bone fragility is the leading cause of bone fractures, a major cause of disability. As the frontline pharmacological treatments for osteoporosis suffer from low patients' adherence and occasional side effects, the importance of diet regimens for the prevention of excessive bone fragility has been increasingly recognized. Indeed, certain diet components have been already associated to a reduced fracture risk. Organosulfur compounds are a broad class of molecules containing sulfur. Among them, several molecules of potential therapeutic interest are found in edible plants belonging to the Allium and Brassica botanical genera. Polysulfides derived from Alliaceae and isothiocyanates derived from Brassicaceae hold remarkable nutraceutical potential as anti-inflammatory, antioxidants, vasorelaxant and hypolipemic. Some of these effects are linked to the ability to release the gasotrasmitter hydrogen sulfide (H2S). Recent preclinical studies have investigated the effect of organosulfur compounds in bone wasting and metabolic bone diseases, revealing a strong potential to preserve skeletal health by exerting cytoprotection and stimulating the bone forming activity by osteoblasts and attenuating bone resorption by osteoclasts. This review is intended for revising evidence from preclinical and epidemiological studies on the skeletal effects of organosulfur molecules of dietary origin, with emphasis on the direct regulation of bone cells by plant-derived polysulfides, glucosinolates and isothiocyanates. Moreover, we highlight the potential molecular mechanisms underlying the biological role of these compounds and revise the importance of the so-called 'H2S-system' on the regulation of bone homeostasis.
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3
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Gong R, Xiao HM, Zhang YH, Zhao Q, Su KJ, Lin X, Mo CL, Zhang Q, Du YT, Lyu FY, Chen YC, Peng C, Liu HM, Hu SD, Pan DY, Chen Z, Li ZF, Zhou R, Wang XF, Lu JM, Ao ZX, Song YQ, Weng CY, Tian Q, Schiller MR, Papasian CJ, Brotto M, Shen H, Shen J, Deng HW. Identification and Functional Characterization of Metabolites for Bone Mass in Peri- and Postmenopausal Chinese Women. J Clin Endocrinol Metab 2021; 106:e3159-e3177. [PMID: 33693744 PMCID: PMC8277206 DOI: 10.1210/clinem/dgab146] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Indexed: 12/14/2022]
Abstract
CONTEXT Although metabolic profiles appear to play an important role in menopausal bone loss, the functional mechanisms by which metabolites influence bone mineral density (BMD) during menopause are largely unknown. OBJECTIVE We aimed to systematically identify metabolites associated with BMD variation and their potential functional mechanisms in peri- and postmenopausal women. DESIGN AND METHODS We performed serum metabolomic profiling and whole-genome sequencing for 517 perimenopausal (16%) and early postmenopausal (84%) women aged 41 to 64 years in this cross-sectional study. Partial least squares regression and general linear regression analysis were applied to identify BMD-associated metabolites, and weighted gene co-expression network analysis was performed to construct co-functional metabolite modules. Furthermore, we performed Mendelian randomization analysis to identify causal relationships between BMD-associated metabolites and BMD variation. Finally, we explored the effects of a novel prominent BMD-associated metabolite on bone metabolism through both in vivo/in vitro experiments. RESULTS Twenty metabolites and a co-functional metabolite module (consisting of fatty acids) were significantly associated with BMD variation. We found dodecanoic acid (DA), within the identified module causally decreased total hip BMD. Subsequently, the in vivo experiments might support that dietary supplementation with DA could promote bone loss, as well as increase the osteoblast and osteoclast numbers in normal/ovariectomized mice. Dodecanoic acid treatment differentially promoted osteoblast and osteoclast differentiation, especially for osteoclast differentiation at higher concentrations in vitro (eg,10, 100 μM). CONCLUSIONS This study sheds light on metabolomic profiles associated with postmenopausal osteoporosis risk, highlighting the potential importance of fatty acids, as exemplified by DA, in regulating BMD.
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Affiliation(s)
- Rui Gong
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
- Tulane Center for Biomedical Informatics and Genomics, School of Medicine, Tulane University, New Orleans, LA, USA
- Cadre Ward Endocrinology Department, Gansu Provincial Hospital, Lanzhou, Gansu, China
| | - Hong-Mei Xiao
- Center of System Biology, Data Information and Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
| | - Yin-Hua Zhang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Qi Zhao
- Department of Preventive Medicine, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Kuan-Jui Su
- Tulane Center for Biomedical Informatics and Genomics, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Xu Lin
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
- Tulane Center for Biomedical Informatics and Genomics, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Cheng-Lin Mo
- Bone-Muscle Research Center, College of Nursing and Health Innovation, The University of Texas-Arlington, Arlington, TX, USA
| | - Qiang Zhang
- Tulane Center for Biomedical Informatics and Genomics, School of Medicine, Tulane University, New Orleans, LA, USA
- School of Nursing and Health, Zhengzhou University, Zhengzhou, China
| | - Ya-Ting Du
- Bone-Muscle Research Center, College of Nursing and Health Innovation, The University of Texas-Arlington, Arlington, TX, USA
- Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Feng-Ye Lyu
- LC-Bio Technologies (Hangzhou) CO.LTD, Hangzhou, China
| | - Yuan-Cheng Chen
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Cheng Peng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Hui-Min Liu
- Center of System Biology, Data Information and Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
| | - Shi-Di Hu
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Dao-Yan Pan
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Zhi Chen
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Zhang-Fang Li
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Rou Zhou
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Xia-Fang Wang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Jun-Min Lu
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Zeng-Xin Ao
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Yu-Qian Song
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Chan-Yan Weng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Qing Tian
- Tulane Center for Biomedical Informatics and Genomics, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Martin R Schiller
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV, USA
| | - Christopher J Papasian
- Department of Biomedical Sciences, University of Missouri-Kansas City, School of Medicine, Kansas City, MO, USA
| | - Marco Brotto
- Bone-Muscle Research Center, College of Nursing and Health Innovation, The University of Texas-Arlington, Arlington, TX, USA
| | - Hui Shen
- Tulane Center for Biomedical Informatics and Genomics, School of Medicine, Tulane University, New Orleans, LA, USA
| | - Jie Shen
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
- Shunde Hospital of Southern Medical University (The First People’s Hospital of Shunde), Foshan, China
- Jie Shen, No.1 of Jiazi Road, Lunjiao, Shunde District, Foshan 528000, Guangdong, China.
| | - Hong-Wen Deng
- Tulane Center for Biomedical Informatics and Genomics, School of Medicine, Tulane University, New Orleans, LA, USA
- Center of System Biology, Data Information and Reproductive Health, School of Basic Medical Science, Central South University, Changsha, China
- Correspondence: Hong-Wen Deng, 1440 Canal St, Suite 2001, New Orleans, LA 70112, USA.
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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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5
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Dos Santos M, Backer S, Saintpierre B, Izac B, Andrieu M, Letourneur F, Relaix F, Sotiropoulos A, Maire P. Single-nucleus RNA-seq and FISH identify coordinated transcriptional activity in mammalian myofibers. Nat Commun 2020; 11:5102. [PMID: 33037211 PMCID: PMC7547110 DOI: 10.1038/s41467-020-18789-8] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 09/10/2020] [Indexed: 12/20/2022] Open
Abstract
Skeletal muscle fibers are large syncytia but it is currently unknown whether gene expression is coordinately regulated in their numerous nuclei. Here we show by snRNA-seq and snATAC-seq that slow, fast, myotendinous and neuromuscular junction myonuclei each have different transcriptional programs, associated with distinct chromatin states and combinations of transcription factors. In adult mice, identified myofiber types predominantly express either a slow or one of the three fast isoforms of Myosin heavy chain (MYH) proteins, while a small number of hybrid fibers can express more than one MYH. By snRNA-seq and FISH, we show that the majority of myonuclei within a myofiber are synchronized, coordinately expressing only one fast Myh isoform with a preferential panel of muscle-specific genes. Importantly, this coordination of expression occurs early during post-natal development and depends on innervation. These findings highlight a previously undefined mechanism of coordination of gene expression in a syncytium.
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Affiliation(s)
| | - Stéphanie Backer
- Université de Paris, Institut Cochin, INSERM, CNRS., 75014, Paris, France
| | | | - Brigitte Izac
- Université de Paris, Institut Cochin, INSERM, CNRS., 75014, Paris, France
| | - Muriel Andrieu
- Université de Paris, Institut Cochin, INSERM, CNRS., 75014, Paris, France
| | - Franck Letourneur
- Université de Paris, Institut Cochin, INSERM, CNRS., 75014, Paris, France
| | - Frederic Relaix
- Université Paris-Est Creteil, INSERM U955 IMRB., 94000, Creteil, France
| | | | - Pascal Maire
- Université de Paris, Institut Cochin, INSERM, CNRS., 75014, Paris, France.
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6
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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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7
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Trout KL, Holian A. Multinucleated giant cell phenotype in response to stimulation. Immunobiology 2020; 225:151952. [PMID: 32517879 DOI: 10.1016/j.imbio.2020.151952] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Revised: 03/29/2020] [Accepted: 04/28/2020] [Indexed: 12/13/2022]
Abstract
Macrophages fuse into multinucleated giant cells (MGC) in many pathological conditions. Despite MGC correlations with granulomas, their functional contribution to inflammation is relatively unknown. An in vitro mouse model of IL-4-induced bone marrow-derived macrophage fusion and microfiltration were used to generate enriched MGC and macrophage populations. Phenotypes were compared in response to well-known inflammatory stimuli, including lipopolysaccharide and crocidolite asbestos. Surface markers were assessed by flow cytometry: CD11b, CD11c, F4/80, and MHC II. Secreted cytokines were assessed by multiplex immunoassay: IFN-γ, IL-1β, IL-6, TNF-α, IL-10, IL-13, and IL-33. Results show that MGC maintained macrophage surface protein expression but lost the ability to produce a cytokine response. This suggests a potentially beneficial role of MGC in isolating the host from a foreign body without contributing to excessive inflammation. This study and future research using other stimulants and environments are important to gaining a fundamental MGC cell biology understanding. This will inform approaches to controlling the foreign body response to particle exposure, medical implants, and many diseases associated with granulomas.
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Affiliation(s)
- Kevin L Trout
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT, United States
| | - Andrij Holian
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, MT, United States.
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8
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Size-Dependent Increase in RNA Polymerase II Initiation Rates Mediates Gene Expression Scaling with Cell Size. Curr Biol 2020; 30:1217-1230.e7. [DOI: 10.1016/j.cub.2020.01.053] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/01/2019] [Accepted: 01/16/2020] [Indexed: 12/19/2022]
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9
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Cinege G, Lerner Z, Magyar LB, Soós B, Tóth R, Kristó I, Vilmos P, Juhász G, Kovács AL, Hegedűs Z, Sensen CW, Kurucz É, Andó I. Cellular Immune Response Involving Multinucleated Giant Hemocytes with Two-Step Genome Amplification in the Drosophilid Zaprionus indianus. J Innate Immun 2019; 12:257-272. [PMID: 31553970 DOI: 10.1159/000502646] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/12/2019] [Indexed: 11/19/2022] Open
Abstract
Previously, a novel cell type, the multinucleated giant hemocyte (MGH) was identified in the ananassae subgroup of Drosophilidae. These cells share several features with mammalian multinucleated giant cells, a syncytium of macrophages formed during granulomatous inflammation. We were able to show that MGHs also differentiate in Zaprionus indianus, an invasive species belonging to the vittiger subgroup of the family, highly resistant to a large number of parasitoid wasp species. We have classified the MGHs of Z. indianusas giant hemocytes belonging to a class of cells which also include elongated blood cells carrying a single nucleus and anuclear structures. They are involved in encapsulating parasites, originate from the lymph gland, can develop by cell fusion, and generally carry many nuclei, while possessing an elaborated system of canals and sinuses, resulting in a spongiform appearance. Their nuclei are all transcriptionally active and show accretion of genetic material. Multinucleation and accumulation of the genetic material in the giant hemocytes represents a two-stage amplification of the genome, while their spongy ultrastructure substantially increases the contact surface with the extracellular space. These features may furnish the giant hemocytes with a considerable metabolic advantage, hence contributing to the mechanism of the effective immune response.
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Affiliation(s)
- Gyöngyi Cinege
- Immunology Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Zita Lerner
- Immunology Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Lilla B Magyar
- Immunology Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.,Doctoral School of Biology, University of Szeged, Szeged, Hungary
| | - Bálint Soós
- Immunology Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Renáta Tóth
- Immunology Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Ildikó Kristó
- Developmental Genetics Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Péter Vilmos
- Developmental Genetics Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Gábor Juhász
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary
| | - Attila L Kovács
- Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary
| | - Zoltán Hegedűs
- Laboratory of Bioinformatics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Christoph W Sensen
- Institute of Computational Biotechnology, Graz University of Technology, Graz, Austria
| | - Éva Kurucz
- Immunology Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - István Andó
- Immunology Unit, Institute of Genetics, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary,
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10
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Cutler AA, Jackson JB, Corbett AH, Pavlath GK. Non-equivalence of nuclear import among nuclei in multinucleated skeletal muscle cells. J Cell Sci 2018; 131:jcs.207670. [PMID: 29361530 DOI: 10.1242/jcs.207670] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 12/21/2017] [Indexed: 01/01/2023] Open
Abstract
Skeletal muscle is primarily composed of large myofibers containing thousands of post-mitotic nuclei distributed throughout a common cytoplasm. Protein production and localization in specialized myofiber regions is crucial for muscle function. Myonuclei differ in transcriptional activity and protein accumulation, but how these differences among nuclei sharing a cytoplasm are achieved is unknown. Regulated nuclear import of proteins is one potential mechanism for regulating transcription spatially and temporally in individual myonuclei. The best-characterized nuclear localization signal (NLS) in proteins is the classical NLS (cNLS), but many other NLS motifs exist. We examined cNLS and non-cNLS reporter protein import using multinucleated muscle cells generated in vitro, revealing that cNLS and non-cNLS nuclear import differs among nuclei in the same cell. Investigation of cNLS nuclear import rates in isolated myofibers ex vivo confirmed differences in nuclear import rates among myonuclei. Analyzing nuclear import throughout myogenesis revealed that cNLS and non-cNLS import varies during differentiation. Taken together, our results suggest that both spatial and temporal regulation of nuclear import pathways are important in muscle cell differentiation and protein regionalization in myofibers.
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Affiliation(s)
- Alicia A Cutler
- Department of Pharmacology, Emory University, Atlanta, GA 30322, USA.,Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, GA 30322, USA
| | | | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Grace K Pavlath
- Department of Pharmacology, Emory University, Atlanta, GA 30322, USA
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11
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Bataillé L, Boukhatmi H, Frendo JL, Vincent A. Dynamics of transcriptional (re)-programming of syncytial nuclei in developing muscles. BMC Biol 2017; 15:48. [PMID: 28599653 PMCID: PMC5466778 DOI: 10.1186/s12915-017-0386-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 05/19/2017] [Indexed: 01/08/2023] Open
Abstract
Background A stereotyped array of body wall muscles enables precision and stereotypy of animal movements. In Drosophila, each syncytial muscle forms via fusion of one founder cell (FC) with multiple fusion competent myoblasts (FCMs). The specific morphology of each muscle, i.e. distinctive shape, orientation, size and skeletal attachment sites, reflects the specific combination of identity transcription factors (iTFs) expressed by its FC. Here, we addressed three questions: Are FCM nuclei naive? What is the selectivity and temporal sequence of transcriptional reprogramming of FCMs recruited into growing syncytium? Is transcription of generic myogenic and identity realisation genes coordinated during muscle differentiation? Results The tracking of nuclei in developing muscles shows that FCM nuclei are competent to be transcriptionally reprogrammed to a given muscle identity, post fusion. In situ hybridisation to nascent transcripts for FCM, FC-generic and iTF genes shows that this reprogramming is progressive, beginning by repression of FCM-specific genes in fused nuclei, with some evidence that FC nuclei retain specific characteristics. Transcription of identity realisation genes is linked to iTF activation and regulated at levels of both transcription initiation rate and period of transcription. The generic muscle differentiation programme is activated independently. Conclusions Transcription reprogramming of fused myoblast nuclei is progressive, such that nuclei within a syncytial fibre at a given time point during muscle development are heterogeneous with regards to specific gene transcription. This comprehensive view of the dynamics of transcriptional (re)programming of post-mitotic nuclei within syncytial cells provides a new framework for understanding the transcriptional control of the lineage diversity of multinucleated cells. Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0386-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Laetitia Bataillé
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Hadi Boukhatmi
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.,Present address: Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, CB2 3DY, UK
| | - Jean-Louis Frendo
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
| | - Alain Vincent
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France.
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12
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Ablation of Y1 receptor impairs osteoclast bone-resorbing activity. Sci Rep 2016; 6:33470. [PMID: 27646989 PMCID: PMC5028844 DOI: 10.1038/srep33470] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/24/2016] [Indexed: 01/09/2023] Open
Abstract
Y1 receptor (Y1R)-signalling pathway plays a pivotal role in the regulation of bone metabolism. The lack of Y1R-signalling stimulates bone mass accretion that has been mainly attributed to Y1R disruption from bone-forming cells. Still, the involvement of Y1R-signalling in the control of bone-resorbing cells remained to be explored. Therefore, in this study we assessed the role of Y1R deficiency in osteoclast formation and resorption activity. Here we demonstrate that Y1R germline deletion (Y1R−/−) led to increased formation of highly multinucleated (n > 8) osteoclasts and enhanced surface area, possibly due to monocyte chemoattractant protein-1 (MCP-1) overexpression regulated by RANKL-signalling. Interestingly, functional studies revealed that these giant Y1R−/− multinucleated cells produce poorly demineralized eroded pits, which were associated to reduce expression of osteoclast matrix degradation markers, such as tartrate-resistant acid phosphatase-5b (TRAcP5b), matrix metalloproteinase-9 (MMP-9) and cathepsin-K (CTSK). Tridimensional (3D) morphologic analyses of resorption pits, using an in-house developed quantitative computational tool (BonePit), showed that Y1R−/− resorption pits displayed a marked reduction in surface area, volume and depth. Together, these data demonstrates that the lack of Y1Rs stimulates the formation of larger multinucleated osteoclasts in vitro with reduced bone-resorbing activity, unveiling a novel therapeutic option for osteoclastic bone diseases based on Y1R-signalling ablation.
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Motiur Rahman M, Takeshita S, Matsuoka K, Kaneko K, Naoe Y, Sakaue-Sawano A, Miyawaki A, Ikeda K. Proliferation-coupled osteoclast differentiation by RANKL: Cell density as a determinant of osteoclast formation. Bone 2015; 81:392-399. [PMID: 26265539 DOI: 10.1016/j.bone.2015.08.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 07/31/2015] [Accepted: 08/07/2015] [Indexed: 11/21/2022]
Abstract
Although it is widely recognized that the osteoclast differentiation induced by RANKL is linked to the anti-proliferative activity of the cytokine, we report here that RANKL in the presence of M-CSF actually stimulates DNA synthesis and cell proliferation during the early proliferative phase (0-48 h) of osteoclastogenesis ex vivo, while the same cytokine exerts an anti-proliferative activity in the latter half (48-96 h). A tracing of the individual cells using Fucci cell cycle indicators showed that waves of active DNA synthesis in the S phase during the period 0-48 h are followed by cell-cycle arrest and cell fusion after 48 h. Inhibition of DNA synthesis with hydroxyurea (HU) during the first half almost completely inhibited osteoclastogenesis; however, the same HU-treated cells, when re-plated at 48 h at increasing cell densities, exhibited restored osteoclast formation, suggesting that a sufficient number of cells, rather than prior DNA synthesis, is the most critical requirement for osteoclast formation. In addition, varying either the number of bone marrow macrophages at the start of osteoclastogenic cultures or pre-osteoclasts halfway through the process had a substantial impact on the number of osteoclasts that finally formed, as well as the timing of the peak of osteoclast formation. Thus, caution should be exerted in the performance of any manipulative procedure, whether pharmacological or genetic, that affects the cell number prior to cell fusion. Such procedures can have a profound effect on the number of osteoclasts that form, the final outcome of "differentiation", leading to misinterpretation of the results.
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Affiliation(s)
- M Motiur Rahman
- Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Sunao Takeshita
- Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Japan.
| | - Kazuhiko Matsuoka
- Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Keiko Kaneko
- Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Yoshinori Naoe
- Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Asako Sakaue-Sawano
- Lab for Cell Function Dynamics, BSI, RIKEN, Wako, Japan; Life Function and Dynamics, ERATO, JST, Wako, Japan
| | - Atsushi Miyawaki
- Lab for Cell Function Dynamics, BSI, RIKEN, Wako, Japan; Life Function and Dynamics, ERATO, JST, Wako, Japan
| | - Kyoji Ikeda
- Department of Bone and Joint Disease, National Center for Geriatrics and Gerontology, Obu, Japan.
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Inoue K, Imai Y. Identification of novel transcription factors in osteoclast differentiation using genome-wide analysis of open chromatin determined by DNase-seq. J Bone Miner Res 2014; 29:1823-32. [PMID: 24677342 DOI: 10.1002/jbmr.2229] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 03/10/2014] [Accepted: 03/14/2014] [Indexed: 12/11/2022]
Abstract
Clarification of the mechanisms underlying osteoclast differentiation enables us to understand the physiology of bone metabolism as well as the pathophysiology of bone diseases such as osteoporosis. Recently, it has been reported that epigenetics can determine cell fate and regulate cell type-specific gene expression. However, little is known about epigenetics during osteoclastogenesis. To reveal a part of epigenetics, especially focused on chromatin dynamics, during early osteoclastogenesis and to identify novel transcription factors involved in osteoclastogenesis, we performed a genome-wide analysis of open chromatin during receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis using DNase I hypersensitive sites sequencing (DNase-seq). DNase-seq was performed using the extracted nuclei from RAW264 cells treated with or without RANKL for 24 hours, followed by several bioinformatic analyses. DNase I hypersensitive sites (DHSs) were dynamically changed during RANKL-induced osteoclastogenesis and they accumulated in promoter regions. The distributions of DHSs among cis-regulatory DNA regions were identical regardless of RANKL stimulation. Motif discovery analysis successfully identified well-known osteoclastogenic transcription factors including Jun, CREB1, FOS, ATF2, and ATF4, but also novel transcription factors for osteoclastogenesis such as Zscan10, Atf1, Nrf1, and Srebf2. siRNA knockdown of these identified novel transcription factors impaired osteoclastogenesis. Taken together, DNase-seq is a useful tool for comprehension of epigenetics, especially chromatin dynamics during osteoclastogenesis and for identification of novel transcription factors involved in osteoclastogenesis. This study may reveal underlying mechanisms that determine cell type-specific differentiation of bone cells and may lead to investigation of novel therapeutic targets for osteoporosis.
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Affiliation(s)
- Kazuki Inoue
- Division of Integrative Pathophysiology, Proteo-Science Center, Graduate School of Medicine, Ehime University, Ehime, Japan; Department of Biological Resources, Integrated Center for Sciences, Ehime University, Ehime, Japan
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de la Rica L, Rodríguez-Ubreva J, García M, Islam ABMMK, Urquiza JM, Hernando H, Christensen J, Helin K, Gómez-Vaquero C, Ballestar E. PU.1 target genes undergo Tet2-coupled demethylation and DNMT3b-mediated methylation in monocyte-to-osteoclast differentiation. Genome Biol 2013; 14:R99. [PMID: 24028770 PMCID: PMC4054781 DOI: 10.1186/gb-2013-14-9-r99] [Citation(s) in RCA: 155] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 09/09/2013] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND DNA methylation is a key epigenetic mechanism for driving and stabilizing cell-fate decisions. Local deposition and removal of DNA methylation are tightly coupled with transcription factor binding, although the relationship varies with the specific differentiation process. Conversion of monocytes to osteoclasts is a unique terminal differentiation process within the hematopoietic system. This differentiation model is relevant to autoimmune disease and cancer, and there is abundant knowledge on the sets of transcription factors involved. RESULTS Here we focused on DNA methylation changes during osteoclastogenesis. Hypermethylation and hypomethylation changes took place in several thousand genes, including all relevant osteoclast differentiation and function categories. Hypomethylation occurred in association with changes in 5-hydroxymethylcytosine, a proposed intermediate toward demethylation. Transcription factor binding motif analysis revealed an over-representation of PU.1, NF-κB, and AP-1 (Jun/Fos) binding motifs in genes undergoing DNA methylation changes. Among these, only PU.1 motifs were significantly enriched in both hypermethylated and hypomethylated genes; ChIP-seq data analysis confirmed its association to both gene sets. Moreover, PU.1 interacts with both DNMT3b and TET2, suggesting its participation in driving hypermethylation and hydroxymethylation-mediated hypomethylation. Consistent with this, siRNA-mediated PU.1 knockdown in primary monocytes impaired the acquisition of DNA methylation and expression changes, and reduced the association of TET2 and DNMT3b at PU.1 targets during osteoclast differentiation. CONCLUSIONS The work described here identifies key changes in DNA methylation during monocyte-to-osteoclast differentiation and reveals novel roles for PU.1 in this process.
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Affiliation(s)
- Lorenzo de la Rica
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Javier Rodríguez-Ubreva
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Mireia García
- Rheumatology Service, Bellvitge University Hospital (HUB), L’Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Abul BMMK Islam
- Department of Experimental and Health Sciences, Barcelona Biomedical Research Park, Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
- Department of Genetic Engineering and Biotechnology, University of Dhaka, Dhaka 1000, Bangladesh
| | - José M Urquiza
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Henar Hernando
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Jesper Christensen
- Biotech Research and Innovation Center (BRIC), Center for Epigenetics University of Copenhagen, Ole Maaløes Vej 5, Copenhagen 2200, Denmark
| | - Kristian Helin
- Biotech Research and Innovation Center (BRIC), Center for Epigenetics University of Copenhagen, Ole Maaløes Vej 5, Copenhagen 2200, Denmark
| | - Carmen Gómez-Vaquero
- Rheumatology Service, Bellvitge University Hospital (HUB), L’Hospitalet de Llobregat, Barcelona 08908, Spain
| | - Esteban Ballestar
- Chromatin and Disease Group, Cancer Epigenetics and Biology Programme (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), L’Hospitalet de Llobregat, Barcelona 08908, Spain
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Notomi T, Ezura Y, Noda M. Identification of two-pore channel 2 as a novel regulator of osteoclastogenesis. J Biol Chem 2012; 287:35057-35064. [PMID: 22833668 DOI: 10.1074/jbc.m111.328930] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Osteoclast differentiation is one of the critical steps that control bone mass levels in osteoporosis, but the molecules involved in osteoclastogenesis are still incompletely understood. Here, we show that two-pore channel 2 (TPC2) is expressed in osteoclast precursor cells, and its knockdown (TPC2-KD) in these cells suppressed RANKL-induced key events including multinucleation, enhancement of tartrate-resistant acid phosphatase (TRAP) activities, and TRAP mRNA expression levels. With respect to intracellular signaling, TPC2-KD reduced the levels of the RANKL-induced dynamic waving of Ca(2+) in RAW cells. The search for the target of TPC2 identified that nuclear localization of NFATc1 is retarded in TPC2-KD cells. Finally, TPC2-KD suppressed osteoclastic pit formation in cultures. We conclude that TPC2 is a novel critical molecule for osteoclastogenesis.
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Affiliation(s)
- Takuya Notomi
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; Global Center of Excellence Program for Molecular Science for Tooth and Bone Diseases, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
| | - Yoichi Ezura
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Masaki Noda
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan; Global Center of Excellence Program for Molecular Science for Tooth and Bone Diseases, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
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17
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Jansen IDC, Vermeer JAF, Bloemen V, Stap J, Everts V. Osteoclast fusion and fission. Calcif Tissue Int 2012; 90:515-22. [PMID: 22527205 PMCID: PMC3349023 DOI: 10.1007/s00223-012-9600-y] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 04/01/2012] [Indexed: 12/13/2022]
Abstract
Osteoclasts are specialized multinucleated cells with the unique capacity to resorb bone. Despite insight into the various steps of the interaction of osteoclast precursors leading to osteoclast formation, surprisingly little is known about what happens with the multinucleated cell itself after it has been formed. Is fusion limited to the short period of its formation, or do osteoclasts have the capacity to change their size and number of nuclei at a later stage? To visualize these processes we analyzed osteoclasts generated in vitro with M-CSF and RANKL from mouse bone marrow and native osteoclasts isolated from rabbit bones by live cell microscopy. We show that osteoclasts fuse not only with mononuclear cells but also with other multinucleated cells. The most intriguing finding was fission of the osteoclasts. Osteoclasts were shown to have the capacity to generate functional multinucleated compartments as well as compartments that contained apoptotic nuclei. These compartments were separated from each other, each giving rise to a novel functional osteoclast or to a compartment that contained apoptotic nuclei. Our findings suggest that osteoclasts have the capacity to regulate their own population in number and function, probably to adapt quickly to changing situations.
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Affiliation(s)
- Ineke D. C. Jansen
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
- Department of Periodontology, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
| | - Jenny A. F. Vermeer
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
| | - Veerle Bloemen
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
| | - Jan Stap
- Van Leeuwenhoek Centre for Advanced Microscopy (LCAM)-AMC, Department of Cell Biology and Histology, Academic Medical Centre (AMC), University of Amsterdam, Meibergdreef 15, 1005 AZ Amsterdam, The Netherlands
| | - Vincent Everts
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), Research Institute MOVE, University of Amsterdam and VU University Amsterdam, Gustav Mahlerlaan 3004, 1081 LA Amsterdam, The Netherlands
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18
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Youn MY, Yokoyama A, Fujiyama-Nakamura S, Ohtake F, Minehata KI, Yasuda H, Suzuki T, Kato S, Imai Y. JMJD5, a Jumonji C (JmjC) domain-containing protein, negatively regulates osteoclastogenesis by facilitating NFATc1 protein degradation. J Biol Chem 2012; 287:12994-3004. [PMID: 22375008 DOI: 10.1074/jbc.m111.323105] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Osteoclastogenesis is a highly regulated process governed by diverse classes of regulators. Among them, nuclear factor of activated T-cells calcineurin-dependent 1 (NFATc1) is the primary osteoclastogenic transcription factor, and its expression is transcriptionally induced during early osteoclastogenesis by receptor activation of nuclear factor κB ligand (RANKL), an osteoclastogenic cytokine. Here, we report the novel enzymatic function of JMJD5, which regulates NFATc1 protein stability. Among the tested Jumonji C (JmjC) domain-containing proteins, decreased mRNA expression levels during osteoclastogenesis were found for JMJD5 in RAW264 cells stimulated by RANKL. To examine the functional role of JMJD5 in osteoclast differentiation, we established stable JMJD5 knockdown cells, and osteoclast formation was assessed. Down-regulated expression of JMJD5 led to accelerated osteoclast formation together with induction of several osteoclast-specific genes such as Ctsk and DC-STAMP, suggesting that JMJD5 is a negative regulator in osteoclast differentiation. Although JMJD5 was recently reported as a histone demethylase for histone H3K36me2, no histone demethylase activity was detected in JMJD5 in vitro or in living cells, even for other methylated histone residues. Instead, JMJD5 co-repressed transcriptional activity by destabilizing NFATc1 protein. Protein hydroxylase activity mediated by the JmjC domain in JMJD5 was required for the observed functions of JMJD5. JMJD5 induced the association of hydroxylated NFATc1 with the E3 ubiquitin ligase Von Hippel-Lindau tumor suppressor (VHL), thereby presumably facilitating proteasomal degradation of NFATc1 via ubiquitination. Taken together, the present study demonstrated that JMJD5 is a post-translational co-repressor for NFATc1 that attenuates osteoclastogenesis.
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Affiliation(s)
- Min-Young Youn
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan
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Hall MN, Corbett AH, Pavlath GK. Regulation of nucleocytoplasmic transport in skeletal muscle. Curr Top Dev Biol 2011; 96:273-302. [PMID: 21621074 DOI: 10.1016/b978-0-12-385940-2.00010-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Proper skeletal muscle function is dependent on spatial and temporal control of gene expression in multinucleated myofibers. In addition, satellite cells, which are tissue-specific stem cells that contribute critically to repair and maintenance of skeletal muscle, are also required for normal muscle physiology. Gene expression in both myofibers and satellite cells is dependent upon nuclear proteins that require facilitated nuclear transport. A unique challenge for myofibers is controlling the transcriptional activity of hundreds of nuclei in a common cytoplasm yet achieving nuclear selectivity in transcription at specific locations such as neuromuscular synapses and myotendinous junctions. Nucleocytoplasmic transport of macromolecular cargoes is regulated by a complex interplay among various components of the nuclear transport machinery, namely nuclear pore complexes, nuclear envelope proteins, and various soluble transport receptors. The focus of this review is to highlight what is known about the nuclear transport machinery and its regulation in skeletal muscle and to consider the unique challenges that multinucleated muscle cells as well as satellite cells encounter in regulating nucleocytoplasmic transport during cell differentiation and tissue adaptation. Understanding how regulated nucleocytoplasmic transport controls gene expression in skeletal muscle may lead to further insights into the mechanisms contributing to muscle growth and maintenance throughout the lifespan of an individual.
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Affiliation(s)
- Monica N Hall
- Graduate Program in Genetics and Molecular Biology, Emory University, Atlanta, Georgia, USA
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