1
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Tajima Y, Shibasaki F, Masai H. Cell fusion upregulates PD-L1 expression for evasion from immunosurveillance. Cancer Gene Ther 2024; 31:158-173. [PMID: 37990063 DOI: 10.1038/s41417-023-00693-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 10/22/2023] [Accepted: 11/07/2023] [Indexed: 11/23/2023]
Abstract
MSCs (mesenchymal stem cells), responsible for tissue repair, rarely undergo cell fusion with somatic cells. Here, we show that ~5% of bladder cancer cells (UMUC-3) fuses with bone marrow-derived MSC (BM-MSC) in co-culture and maintains high tumorigenicity. In eleven fusion cell clones that have been established, Mb-scale deletions carried by the bladder cancer cells are mostly absent in the fusion cells, but copy number gains contributed by the cancer cells have stayed. Fusion cells exhibit increased populations of mitotic cells with 3-polar spindles, indicative of genomic instability. They grow faster in vitro and exhibit higher colony formation in anchorage-independent growth assay in soft agar than the parent UMUC-3 does. Fusion cells develop tumors, after 4 weeks of time lag, as efficiently as the parent UMUC-3 does in xenograft experiments. 264 genes are identified whose expression is specifically altered in the fusion cells. Many of them are interferon-stimulated genes (ISG), but are activated in a manner independent of interferon. Among them, we show that PD-L1 is induced in fusion cells, and its knockout decreases tumorigenesis in a xenograft model. PD-L1 is induced in a manner independent of STAT1 known to regulate PD-L1 expression, but is regulated by histone modification, and is likely to inhibit phagocytosis by PD1-expressing macrophages, thus protecting cancer cells from immunological attacks. The fusion cells overexpress multiple cytokines including CCL2 that cause tumor progression by converting infiltrating macrophages to tumor-associated-macrophage (TAM). The results present mechanisms of how cell fusion promotes tumorigenesis, revealing a novel link between cell fusion and PD-L1, and underscore the efficacy of cancer immunotherapy.
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Affiliation(s)
- Youichi Tajima
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan.
| | - Futoshi Shibasaki
- Center for Medical Research Cooperation, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
| | - Hisao Masai
- Genome Dynamics Project, Department of Basic Medical Sciences, Tokyo Metropolitan Institute of Medical Science, Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan.
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2
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Kloc M, Tworzydło W, Szklarzewicz T. Germline and Somatic Cell Syncytia in Insects. Results Probl Cell Differ 2024; 71:47-63. [PMID: 37996672 DOI: 10.1007/978-3-031-37936-9_3] [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
Syncytia are common in the animal and plant kingdoms both under normal and pathological conditions. They form through cell fusion or division of a founder cell without cytokinesis. A particular type of syncytia occurs in invertebrate and vertebrate gametogenesis when the founder cell divides several times with partial cytokinesis producing a cyst (nest) of germ line cells connected by cytoplasmic bridges. The ultimate destiny of the cyst's cells differs between animal groups. Either all cells of the cyst become the gametes or some cells endoreplicate or polyploidize to become the nurse cells (trophocytes). Although many types of syncytia are permanent, the germ cell syncytium is temporary, and eventually, it separates into individual gametes. In this chapter, we give an overview of syncytium types and focus on the germline and somatic cell syncytia in various groups of insects. We also describe the multinuclear giant cells, which form through repetitive nuclear divisions and cytoplasm hypertrophy, but without cell fusion, and the accessory nuclei, which bud off the oocyte nucleus, migrate to its cortex and become included in the early embryonic syncytium.
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Affiliation(s)
- Malgorzata Kloc
- The Houston Methodist Research Institute, Houston, TX, USA.
- The Houston Methodist Hospital, Department of Surgery, Houston, TX, USA.
- Department of Genetics, MD Anderson Cancer Center, The University of Texas, Houston, TX, USA.
| | - Wacław Tworzydło
- Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
| | - Teresa Szklarzewicz
- Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Faculty of Biology, Jagiellonian University in Krakow, Krakow, Poland
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3
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Dai H, Jiang D, Zhou W, Qiu X. Characteristics and Clinical Implications of Immunoglobulins Derived from Non B Cells in the Skin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1445:151-156. [PMID: 38967757 DOI: 10.1007/978-981-97-0511-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/06/2024]
Abstract
Skin is the most prominent tissue and organ, as well as the first line of defence, of the body. Because it is situated on the body's surface, it is constantly exposed to microbial, chemical, and physical factors such as mechanical stimulation. Therefore, skin has evolved substantial immune defences, regenerative ability, and anti-injury capacity. Epidermal cells produce antibacterial peptides that play a role in immune defence under physiological conditions. Additionally, IgG or IgA in the skin also participates in local anti-infective immunity. However, based on the classical theory of immunology, Ig can only be produced by B cells which should be derived from local B cells. This year, thanks to the discovery of Ig derived from non B cells (non B-Ig), Ig has also been found to be expressed in epidermal cells and contributes to immune defence. Epidermal cell-derived IgG and IgA have been demonstrated to have potential antibody activity by binding to pathogens. However, these epidermal cell-derived Igs show different microbial binding characteristics. For instance, IgG binds to Staphylococcus aureus and IgA binds to Staphylococcus epidermidis. Epidermal cells producing IgG and IgA may serve as an effective defense mechanism alongside B cells, providing a novel insight into skin immunity.
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Affiliation(s)
- Hui Dai
- Department of Immunology, School of Basic Medical Sciences, NHC Key Laboratory of Medical Immunology, Peking University, Beijing, China.
| | - Dongyang Jiang
- Department of Cardiology, Pan-vascular Research Institute, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wenjing Zhou
- Institute of Thoracic Oncology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoyan Qiu
- Department of Immunology, School of Basic Medical Sciences, Peking University, Beijing, China
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4
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Shimode S. Acquisition and Exaptation of Endogenous Retroviruses in Mammalian Placenta. Biomolecules 2023; 13:1482. [PMID: 37892164 PMCID: PMC10604696 DOI: 10.3390/biom13101482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 10/29/2023] Open
Abstract
Endogenous retroviruses (ERVs) are retrovirus-like sequences that were previously integrated into the host genome. Although most ERVs are inactivated by mutations, deletions, or epigenetic regulation, some remain transcriptionally active and impact host physiology. Several ERV-encoded proteins, such as Syncytins and Suppressyn, contribute to placenta acquisition, a crucial adaptation in mammals that protects the fetus from external threats and other risks while enabling the maternal supply of oxygen, nutrients, and antibodies. In primates, Syncytin-1 and Syncytin-2 facilitate cell-cell fusion for placental formation. Suppressyn is the first ERV-derived protein that inhibits cell fusion by binding to ASCT2, the receptor for Syncytin-1. Furthermore, Syncytin-2 likely inserted into the genome of the common ancestor of Anthropoidea, whereas Syncytin-1 and Suppressyn likely inserted into the ancestor of catarrhines; however, they were inactivated in some lineages, suggesting that multiple exaptation events had occurred. This review discusses the role of ERV-encoded proteins, particularly Syncytins and Suppressyn, in placental development and function, focusing on the integration of ERVs into the host genome and their contribution to the genetic mechanisms underlying placentogenesis. This review provides valuable insights into the molecular and genetic aspects of placentation, potentially shedding light on broader evolutionary and physiological processes in mammals.
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Affiliation(s)
- Sayumi Shimode
- Genome Editing Innovation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-0046, Japan;
- Graduate School of Integrated Sciences for Life, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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5
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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: 30] [Impact Index Per Article: 15.0] [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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6
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Zhou Z, Zhang X, Lei X, Xiao X, Jiao T, Ma R, Dong X, Jiang Q, Wang W, Shi Y, Zheng T, Rao J, Xiang Z, Ren L, Deng T, Jiang Z, Dou Z, Wei W, Wang J. Sensing of cytoplasmic chromatin by cGAS activates innate immune response in SARS-CoV-2 infection. Signal Transduct Target Ther 2021; 6:382. [PMID: 34732709 PMCID: PMC8564796 DOI: 10.1038/s41392-021-00800-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 10/14/2021] [Accepted: 10/19/2021] [Indexed: 01/07/2023] Open
Abstract
The global coronavirus disease 2019 (COVID-19) pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a positive-sense RNA virus. How the host immune system senses and responds to SARS-CoV-2 infection remain largely unresolved. Here, we report that SARS-CoV-2 infection activates the innate immune response through the cytosolic DNA sensing cGAS-STING pathway. SARS-CoV-2 infection induces the cellular level of 2′3′-cGAMP associated with STING activation. cGAS recognizes chromatin DNA shuttled from the nucleus as a result of cell-to-cell fusion upon SARS-CoV-2 infection. We further demonstrate that the expression of spike protein from SARS-CoV-2 and ACE2 from host cells is sufficient to trigger cytoplasmic chromatin upon cell fusion. Furthermore, cytoplasmic chromatin-cGAS-STING pathway, but not MAVS-mediated viral RNA sensing pathway, contributes to interferon and pro-inflammatory gene expression upon cell fusion. Finally, we show that cGAS is required for host antiviral responses against SARS-CoV-2, and a STING-activating compound potently inhibits viral replication. Together, our study reported a previously unappreciated mechanism by which the host innate immune system responds to SARS-CoV-2 infection, mediated by cytoplasmic chromatin from the infected cells. Targeting the cytoplasmic chromatin-cGAS-STING pathway may offer novel therapeutic opportunities in treating COVID-19. In addition, these findings extend our knowledge in host defense against viral infection by showing that host cells’ self-nucleic acids can be employed as a “danger signal” to alarm the immune system.
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Affiliation(s)
- Zhuo Zhou
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
| | - Xinyi Zhang
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Xiaobo Lei
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China.,Key Laboratory of Respiratory Disease Pathogenomics, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China.,Christophe Merieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Xia Xiao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Tao Jiao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Ruiyi Ma
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Xiaojing Dong
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Qi Jiang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Wenjing Wang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Yujin Shi
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Tian Zheng
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Jian Rao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Zichun Xiang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China.,Key Laboratory of Respiratory Disease Pathogenomics, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China.,Christophe Merieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Lili Ren
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China.,Key Laboratory of Respiratory Disease Pathogenomics, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China.,Christophe Merieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China
| | - Tao Deng
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhengfan Jiang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Pseking University, Beijing, 100871, China.,Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Zhixun Dou
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA.,Harvard Stem Cell Institute, Harvard University, Cambridge, MA, USA.,Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Wensheng Wei
- Biomedical Pioneering Innovation Center, Beijing Advanced Innovation Center for Genomics, Peking-Tsinghua Center for Life Sciences, Peking University Genome Editing Research Center, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
| | - Jianwei Wang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China. .,Key Laboratory of Respiratory Disease Pathogenomics, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China. .,Christophe Merieux Laboratory, Institute of Pathogen Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, 100730, Beijing, P.R. China.
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7
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Goswami R, Arya RK, Sharma S, Dutta B, Stamov DR, Zhu X, Rahaman SO. Mechanosensing by TRPV4 mediates stiffness-induced foreign body response and giant cell formation. Sci Signal 2021; 14:eabd4077. [PMID: 34726952 PMCID: PMC9976933 DOI: 10.1126/scisignal.abd4077] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Implantation of biomaterials or devices into soft tissue often leads to the development of the foreign body response (FBR), an inflammatory condition that can cause implant failure, tissue injury, and death of the patient. Macrophages accumulate and fuse to generate destructive foreign body giant cells (FBGCs) at the tissue-implant interface, leading to the development of fibrous scar tissue around the implant that is generated by myofibroblasts. We previously showed that the FBR in vivo and FBGC formation in vitro require transient receptor potential vanilloid 4 (TRPV4), a mechanosensitive ion channel. Here, we report that TRPV4 was required specifically for the FBR induced by implant stiffness independently of biochemical cues and for intracellular stiffening that promotes FBGC formation in vitro. TRPV4 deficiency reduced collagen deposition and the accumulation of macrophages, FBGCs, and myofibroblasts at stiff, but not soft, implants in vivo and inhibited macrophage-induced differentiation of wild-type fibroblasts into myofibroblasts in vitro. Atomic force microscopy demonstrated that TRPV4 was required for implant-adjacent tissue stiffening in vivo and for cytoskeletal remodeling and intracellular stiffening induced by fusogenic cytokines in vitro. Together, these data suggest a mechanism whereby a reciprocal functional interaction between TRPV4 and substrate stiffness leads to cytoskeletal remodeling and cellular force generation to promote FBGC formation during the FBR.
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Affiliation(s)
- Rishov Goswami
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
| | - Rakesh K. Arya
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
| | - Shweta Sharma
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
| | - Bidisha Dutta
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA
| | - Dimitar R. Stamov
- JPK BioAFM Business, Nano Surfaces Division, Bruker Nano GmbH, Am Studio 2D, 12489 Berlin, Germany
| | - Xiaoping Zhu
- Department of Veterinary Medicine, University of Maryland, College Park, MD 20742, USA
| | - Shaik O. Rahaman
- Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742, USA.,Corresponding author.:
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8
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YAP1 nuclear efflux and transcriptional reprograming follow membrane diminution upon VSV-G-induced cell fusion. Nat Commun 2021; 12:4502. [PMID: 34301937 PMCID: PMC8302681 DOI: 10.1038/s41467-021-24708-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 06/24/2021] [Indexed: 02/07/2023] Open
Abstract
Cells in many tissues, such as bone, muscle, and placenta, fuse into syncytia to acquire new functions and transcriptional programs. While it is known that fused cells are specialized, it is unclear whether cell-fusion itself contributes to programmatic-changes that generate the new cellular state. Here, we address this by employing a fusogen-mediated, cell-fusion system to create syncytia from undifferentiated cells. RNA-Seq analysis reveals VSV-G-induced cell fusion precedes transcriptional changes. To gain mechanistic insights, we measure the plasma membrane surface area after cell-fusion and observe it diminishes through increases in endocytosis. Consequently, glucose transporters internalize, and cytoplasmic glucose and ATP transiently decrease. This reduced energetic state activates AMPK, which inhibits YAP1, causing transcriptional-reprogramming and cell-cycle arrest. Impairing either endocytosis or AMPK activity prevents YAP1 inhibition and cell-cycle arrest after fusion. Together, these data demonstrate plasma membrane diminishment upon cell-fusion causes transient nutrient stress that may promote transcriptional-reprogramming independent from extrinsic cues.
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9
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Elson A, Stein M, Rabie G, Barnea-Zohar M, Winograd-Katz S, Reuven N, Shalev M, Sekeres J, Kanaan M, Tuckermann J, Geiger B. Sorting Nexin 10 as a Key Regulator of Membrane Trafficking in Bone-Resorbing Osteoclasts: Lessons Learned From Osteopetrosis. Front Cell Dev Biol 2021; 9:671210. [PMID: 34095139 PMCID: PMC8173195 DOI: 10.3389/fcell.2021.671210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/23/2021] [Indexed: 12/30/2022] Open
Abstract
Bone homeostasis is a complex, multi-step process, which is based primarily on a tightly orchestrated interplay between bone formation and bone resorption that is executed by osteoblasts and osteoclasts (OCLs), respectively. The essential physiological balance between these cells is maintained and controlled at multiple levels, ranging from regulated gene expression to endocrine signals, yet the underlying cellular and molecular mechanisms are still poorly understood. One approach for deciphering the mechanisms that regulate bone homeostasis is the characterization of relevant pathological states in which this balance is disturbed. In this article we describe one such “error of nature,” namely the development of acute recessive osteopetrosis (ARO) in humans that is caused by mutations in sorting nexin 10 (SNX10) that affect OCL functioning. We hypothesize here that, by virtue of its specific roles in vesicular trafficking, SNX10 serves as a key selective regulator of the composition of diverse membrane compartments in OCLs, thereby affecting critical processes in the sequence of events that link the plasma membrane with formation of the ruffled border and with extracellular acidification. As a result, SNX10 determines multiple features of these cells either directly or, as in regulation of cell-cell fusion, indirectly. This hypothesis is further supported by the similarities between the cellular defects observed in OCLs form various models of ARO, induced by mutations in SNX10 and in other genes, which suggest that mutations in the known ARO-associated genes act by disrupting the same plasma membrane-to-ruffled border axis, albeit to different degrees. In this article, we describe the population genetics and spread of the original arginine-to-glutamine mutation at position 51 (R51Q) in SNX10 in the Palestinian community. We further review recent studies, conducted in animal and cellular model systems, that highlight the essential roles of SNX10 in critical membrane functions in OCLs, and discuss possible future research directions that are needed for challenging or substantiating our hypothesis.
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Affiliation(s)
- Ari Elson
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Merle Stein
- Institute of Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Grace Rabie
- Hereditary Research Laboratory and Department of Life Sciences, Bethlehem University, Bethlehem, Palestine
| | - Maayan Barnea-Zohar
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | | | - Nina Reuven
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Moran Shalev
- Department of Molecular Genetics, The Weizmann Institute of Science, Rehovot, Israel
| | - Juraj Sekeres
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
| | - Moien Kanaan
- Hereditary Research Laboratory and Department of Life Sciences, Bethlehem University, Bethlehem, Palestine
| | - Jan Tuckermann
- Institute of Comparative Molecular Endocrinology, University of Ulm, Ulm, Germany
| | - Benjamin Geiger
- Department of Immunology, The Weizmann Institute of Science, Rehovot, Israel
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10
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Wang HF, Xiang W, Xue BZ, Wang YH, Yi DY, Jiang XB, Zhao HY, Fu P. Cell fusion in cancer hallmarks: Current research status and future indications. Oncol Lett 2021; 22:530. [PMID: 34055095 PMCID: PMC8138896 DOI: 10.3892/ol.2021.12791] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 04/09/2021] [Indexed: 12/13/2022] Open
Abstract
Cell fusion is involved in several physiological processes, such as reproduction, development and immunity. Although cell fusion in tumors was reported 130 years ago, it has recently attracted great interest, with recent progress in tumorigenesis research. However, the role of cell fusion in tumor progression remains unclear. The pattern of cell fusion and its role under physiological conditions are the basis for our understanding of the pathological role of cell fusion. However, the role of cell fusion in tumors and its functions are complicated. Cell fusion can directly increase tumor heterogeneity by forming polyploids or aneuploidies. Several studies have reported that cell fusion is associated with tumorigenesis, metastasis, recurrence, drug resistance and the formation of cancer stem cells. Given the diverse roles cell fusion plays in different tumor phenotypes, methods based on targeted cell fusion have been designed to treat tumors. Research on cell fusion in tumors may provide novel ideas for further treatment.
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Affiliation(s)
- Hao-Fei Wang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Wei Xiang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Bing-Zhou Xue
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Yi-Hao Wang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Dong-Ye Yi
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Xiao-Bing Jiang
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Hong-Yang Zhao
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
| | - Peng Fu
- Department of Neurosurgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, P.R. China
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11
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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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12
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Behzatoglu K. Osteoclasts in Tumor Biology: Metastasis and Epithelial-Mesenchymal-Myeloid Transition. Pathol Oncol Res 2021; 27:609472. [PMID: 34257573 PMCID: PMC8262221 DOI: 10.3389/pore.2021.609472] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 02/24/2021] [Indexed: 11/30/2022]
Abstract
Osteoclast is a specialized cell that originates from monocytic lineage, communicates closely with osteoblasts under physiological conditions, participates in bone modeling and re-modeling, contributes to calcium homeostasis and osteoimmunity. In pathological conditions, it is involved in many tumors such as giant cell bone tumor (osteoclastoma), aneurysmal bone cyst, osteosarcoma, and metastatic cancers, and it usually causes local spread and progression of the tumor, working against the host. Since osteoclasts play an active role in primary bone tumors and bone metastases, the use of anti-osteoclastic agents significantly reduces the mortality and morbidity rates of patients by preventing the progression and local spread of tumors. Osteoclasts also accompany undifferentiated carcinomas of many organs, especially pancreas, thyroid, bladder and ovary. Undifferentiated carcinomas rich in osteoclasts have osteoclastoma-like histology. In these organs, osteoclastoma-like histology may accompany epithelial carcinomas, and de novo, benign and borderline tumors. Mature and immature myeloid cells, including osteoclasts, play an active role in the tumor progression in primary and metastatic tumor microenvironment, in epithelial-mesenchymal transition (EMT), mesenchymal-epithelial-transition (MET), and cancer stem cell formation. Additionally, they are the most suitable candidates for cancer cells in cell fusion due to their evolutionary fusion capabilities. Myeloid features and markers (CD163, CD33, CD68 etc.) can be seen in metastatic cancer cells. Consequently, they provide metastatic cancer cells with motility, margination, transmigration, chemotaxis, phagocytosis, angiogenesis, matrix degradation, and resistance to chemotherapy. For these reasons, we think that the concept of Epithelial-Mesencyhmal-Myeloid-Transition (EMMT) will be more accurate than EMT for cancer cells with myeloid properties.
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13
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Arya RK, Goswami R, Rahaman SO. Mechanotransduction via a TRPV4-Rac1 signaling axis plays a role in multinucleated giant cell formation. J Biol Chem 2021; 296:100129. [PMID: 33262217 PMCID: PMC7948992 DOI: 10.1074/jbc.ra120.014597] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 11/13/2020] [Accepted: 12/01/2020] [Indexed: 12/21/2022] Open
Abstract
Multinucleated giant cells are formed by the fusion of macrophages and are a characteristic feature in numerous pathophysiological conditions including the foreign body response (FBR). Foreign body giant cells (FBGCs) are inflammatory and destructive multinucleated macrophages and may cause damage and/or rejection of implants. However, while these features of FBGCs are well established, the molecular mechanisms underlying their formation remain elusive. Improved understanding of the molecular mechanisms underlying the formation of FBGCs may permit the development of novel implants that eliminate or reduce the FBR. Our previous study showed that transient receptor potential vanilloid 4 (TRPV4), a mechanosensitive ion channel/receptor, is required for FBGC formation and FBR to biomaterials. Here, we have determined that (a) TRPV4 is directly involved in fusogenic cytokine (interleukin-4 plus granulocyte macrophage-colony stimulating factor)-induced activation of Rac1, in bone marrow-derived macrophages; (b) TRPV4 directly interacts with Rac1, and their interaction is further augmented in the presence of fusogenic cytokines; (c) TRPV4-dependent activation of Rac1 is essential for the augmentation of intracellular stiffness and regulation of cytoskeletal remodeling; and (d) TRPV4-Rac1 signaling axis is critical in fusogenic cytokine-induced FBGC formation. Together, these data suggest a novel mechanism whereby a functional interaction between TRPV4 and Rac1 leads to cytoskeletal remodeling and intracellular stiffness generation to modulate FBGC formation.
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Affiliation(s)
- Rakesh K Arya
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA
| | - Rishov Goswami
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA
| | - Shaik O Rahaman
- Department of Nutrition and Food Science, University of Maryland, College Park, Maryland, USA.
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14
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Kim H, Takegahara N, Walsh MC, Ueda J, Fujihara Y, Ikawa M, Choi Y. Protocadherin-7 contributes to maintenance of bone homeostasis through regulation of osteoclast multinucleation. BMB Rep 2020. [PMID: 32635982 PMCID: PMC7526982 DOI: 10.5483/bmbrep.2020.53.9.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Osteoclasts are hematopoietic-derived cells that resorb bone. They are required to maintain proper bone homeostasis and skeletal strength. Although osteoclast differentiation depends on receptor activator of NFκB ligand (RANKL) stimulation, additional molecules further contribute to osteoclast maturation. Here, we demonstrate that protocadherin-7 (Pcdh7) regulates formation of multinucleated osteoclasts and contributes to maintenance of bone homeostasis. We found that Pcdh7 expression is induced by RANKL stimulation, and that RNAi-mediated knockdown of Pcdh7 resulted in impaired formation of osteoclasts. We generated Pcdh7-deficient mice and found increased bone mass due to decreased bone resorption but without any defect in bone formation. Using an in vitro culture system, it was revealed that formation of multinucleated osteoclasts is impaired in Pcdh7-deficient cultures, while no apparent defects were observed in differentiation and function of Pcdh7-deficient osteoblasts. Taken together, these results reveal an osteoclast cell-intrinsic role for Pcdh7 in maintaining bone homeostasis.
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Affiliation(s)
- Hyunsoo Kim
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Noriko Takegahara
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Matthew C. Walsh
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jun Ueda
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yoshitaka Fujihara
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yongwon Choi
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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15
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Kim H, Takegahara N, C M, Walsh, Ueda J, Fujihara Y, Ikawa M, Choi Y. Protocadherin-7 contributes to maintenance of bone homeostasis through regulation of osteoclast multinucleation. BMB Rep 2020; 53:472-477. [PMID: 32635982 PMCID: PMC7526982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 03/26/2020] [Accepted: 04/06/2020] [Indexed: 02/15/2024] Open
Abstract
Osteoclasts are hematopoietic-derived cells that resorb bone. They are required to maintain proper bone homeostasis and skeletal strength. Although osteoclast differentiation depends on receptor activator of NF-κB ligand (RANKL) stimulation, additional molecules further contribute to osteoclast maturation. Here, we demonstrate that protocadherin-7 (Pcdh7) regulates formation of multinucleated osteoclasts and contributes to maintenance of bone homeostasis. We found that Pcdh7 expression is induced by RANKL stimulation, and that RNAi-mediated knockdown of Pcdh7 resulted in impaired formation of osteoclasts. We generated Pcdh7-deficient mice and found increased bone mass due to decreased bone resorption but without any defect in bone formation. Using an in vitro culture system, it was revealed that formation of multinucleated osteoclasts is impaired in Pcdh7-deficient cultures, while no apparent defects were observed in differentiation and function of Pcdh7-deficient osteoblasts. Taken together, these results reveal an osteoclast cell-intrinsic role for Pcdh7 in maintaining bone homeostasis. [BMB Reports 2020; 53(9): 472-477].
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Affiliation(s)
- Hyunsoo Kim
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Noriko Takegahara
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Matthew C
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Walsh
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jun Ueda
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yoshitaka Fujihara
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yongwon Choi
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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16
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Zhang LN, Zhang DD, Yang L, Gu YX, Zuo QP, Wang HY, Xu J, Liu DX. Roles of cell fusion between mesenchymal stromal/stem cells and malignant cells in tumor growth and metastasis. FEBS J 2020; 288:1447-1456. [PMID: 33070450 DOI: 10.1111/febs.15483] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/21/2020] [Accepted: 07/08/2020] [Indexed: 01/02/2023]
Abstract
Invasion and metastasis are the basic characteristics and important markers of malignant tumors, which are also the main cause of death in cancer patients. Epithelial-mesenchymal transition (EMT) is recognized as the first step of tumor invasion and metastasis. Many studies have demonstrated that cell fusion is a common phenomenon and plays a critical role in cancer development and progression. At present, cancer stem cell fusion has been considered as a new mechanism of cancer metastasis. Mesenchymal stromal/stem cell (MSC) is a kind of adult stem cells with high self-renewal ability and multidifferentiation potential, which is used as a very promising fusogenic candidate in the tumor microenvironment and has a crucial role in cancer progression. Many research results have shown that MSCs are involved in the regulation of tumor growth and metastasis through cell fusion. However, the role of cell fusion between MSCs and malignant cells in tumor growth and metastasis is still controversial. Several studies have demonstrated that MSCs can enhance malignant characteristics, promoting tumor growth and metastasis by fusing with malignant cells, while other conflicting reports believe that MSCs can reduce tumorigenicity upon fusion with malignant cells. In this review, we summarize the recent research on cell fusion events between MSCs and malignant cells in tumor growth and metastasis. The elucidation of the molecular mechanisms between MSC fusion and tumor metastasis may provide an effective strategy for tumor biotherapy.
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Affiliation(s)
- Li-Na Zhang
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Di-Di Zhang
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Lei Yang
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Yu-Xuan Gu
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Qiu-Ping Zuo
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Hao-Yi Wang
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Jia Xu
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
| | - Dian-Xin Liu
- Beijing International Science and Technology Cooperation Base of Antivirus Drug, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, China
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17
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Kang JH, Ko HM, Han GD, Lee SY, Moon JS, Kim MS, Koh JT, Kim SH. Dual role of phosphatidylserine and its receptors in osteoclastogenesis. Cell Death Dis 2020; 11:497. [PMID: 32612123 PMCID: PMC7330034 DOI: 10.1038/s41419-020-2712-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/11/2020] [Accepted: 06/15/2020] [Indexed: 12/13/2022]
Abstract
Fusion and apoptosis share a breakdown of the membrane phospholipids asymmetry, modes of which are largely unknown in osteoclastogenesis. Here, we investigated the externalization of phosphatidylserine (PS) and its receptors, and their biological functions in osteoclastogenesis. Strong immunoreactivities in vivo for the PS receptors TIM4, BAI1, and STAB2 were observed in the TRAP-positive multinucleated cells in the alveolar bone that was being remodeled around the developing dental follicles in rats. These receptors were significantly upregulated during M-CSF/RANKL-induced in vitro osteoclastogenesis using mouse bone marrow-derived cells. PS externalization in preosteoclasts was increased by the M-CSF/RANKL treatment. Multinucleation of preosteoclasts was markedly inhibited by antibodies against PS and its receptors. Among the investigated lipid transporter proteins, floppases (Abcb4, Abcc5, and Abcg1) were upregulated, whereas flippases (Atp11c and Atp8a1) downregulated during osteoclastogenesis. Preosteoclast fusion was markedly blocked by the ATPase inhibitor Na3VO4 and siRNAs against Abcc5 and Abcg1, revealing the importance of these lipid transporters in PS externalization. Further, the levels of Cd47 and Cd31, don't-eat-me signal inducers, were increased or sustained in the early phase of osteoclastogenesis, whereas those of AnnexinI and Mfg-e8, eat-me signals inducers, were increased in the late apoptotic phase. In addition, Z-VAD-FMK, a pan caspase inhibitor, had no effect on preosteoclast fusion in the early phase of osteoclastogenesis, whereas Abs against PS, TIM4, and BAI1 decreased osteoclast apoptosis during the late phase. These results suggest that PS externalization is essential for the whole process of osteoclastogenesis and share PS receptors and transporters in the early stage fusion and late stage apoptosis. Therefore, modulation of PS and its receptors could be a useful strategy to develop anti-bone resorptive agents.
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Affiliation(s)
- Jee-Hae Kang
- Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 61186, Korea
| | - Hyun-Mi Ko
- Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 61186, Korea
| | - Geum-Dong Han
- Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 61186, Korea
| | - Su-Young Lee
- Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 61186, Korea
| | - Jung-Sun Moon
- Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 61186, Korea
| | - Min-Seok Kim
- Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 61186, Korea
| | - Jeong-Tae Koh
- Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 61186, Korea
| | - Sun-Hun Kim
- Dental Science Research Institute, School of Dentistry, Chonnam National University, Gwangju, 61186, Korea.
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18
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Kitano VJF, Ohyama Y, Hayashida C, Ito J, Okayasu M, Sato T, Ogasawara T, Tsujita M, Kakino A, Shimada J, Sawamura T, Hakeda Y. LDL uptake-dependent phosphatidylethanolamine translocation to the cell surface promotes fusion of osteoclast-like cells. J Cell Sci 2020; 133:jcs243840. [PMID: 32295848 DOI: 10.1242/jcs.243840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/25/2020] [Indexed: 11/20/2022] Open
Abstract
Osteoporosis is associated with vessel diseases attributed to hyperlipidemia, and bone resorption by multinucleated osteoclasts is related to lipid metabolism. In this study, we generated low-density lipoprotein receptor (LDLR)/lectin-like oxidized LDL receptor-1 (LOX-1, also known as Olr1) double knockout (dKO) mice. We found that, like LDLR single KO (sKO), LDLR/LOX-1 dKO impaired cell-cell fusion of osteoclast-like cells (OCLs). LDLR/LOX-1 dKO and LDLR sKO preosteoclasts exhibited decreased uptake of LDL. The cell surface cholesterol levels of both LDLR/LOX-1 dKO and LDLR sKO osteoclasts were lower than the levels of wild-type OCLs. Additionally, the amount of phosphatidylethanolamine (PE) on the cell surface was attenuated in LDLR/LOX-1 dKO and LDLR sKO preosteoclasts, whereas the PE distribution in wild-type OCLs was concentrated on the filopodia in contact with neighboring cells. Abrogation of the ATP binding cassette G1 (ABCG1) transporter, which transfers PE to the cell surface, caused decreased PE translocation to the cell surface and subsequent cell-cell fusion. The findings of this study indicate the involvement of a novel cascade (LDLR∼ABCG1∼PE translocation to cell surface∼cell-cell fusion) in multinucleation of OCLs.
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Affiliation(s)
- Victor J F Kitano
- Division of Oral Anatomy, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
- Division of Oral and Maxillofacial Surgery, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
| | - Yoko Ohyama
- Division of Oral Anatomy, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
- Division of Oral and Maxillofacial Surgery, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
| | - Chiyomi Hayashida
- Division of Oral Anatomy, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
| | - Junta Ito
- Josai University, Faculty of Pharmacy and Pharmaceutical Sciences, Department of Clinical Dietetics and Human Nutrition, Sakado, Saitama 350-0295, Japan
| | - Mari Okayasu
- Division of Oral-maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Hongo, Tokyo 113-8655, Japan
| | - Takuya Sato
- Division of Oral Anatomy, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
| | - Toru Ogasawara
- Division of Oral-maxillofacial Surgery, Dentistry and Orthodontics, The University of Tokyo Hospital, Hongo, Tokyo 113-8655, Japan
| | - Maki Tsujita
- Department of Biochemistry, Graduate School of Medical Sciences, Nagoya City University, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi 467-8601, Japan
| | - Akemi Kakino
- Department of Physiology, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan
| | - Jun Shimada
- Division of Oral and Maxillofacial Surgery, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
| | - Tatsuya Sawamura
- Department of Physiology, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan
| | - Yoshiyuki Hakeda
- Division of Oral Anatomy, Meikai University School of Dentistry, Sakado, Saitama 350-0283, Japan
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19
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Wang R, Lewis MS, Lyu J, Zhau HE, Pandol SJ, Chung LWK. Cancer-stromal cell fusion as revealed by fluorescence protein tracking. Prostate 2020; 80:274-283. [PMID: 31846114 PMCID: PMC6949378 DOI: 10.1002/pros.23941] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 12/06/2019] [Indexed: 12/29/2022]
Abstract
PURPOSE We previously determined that cancer-stromal interaction was a direct route to tumor cell heterogeneity progression, since cancer-stromal cell fusion in coculture resulted in the creation of heterogeneous clones of fusion hybrid progeny. In this report, we modified the cancer-stromal coculture system to establish optimal experimental conditions for investigating cell fusion machinery and the mechanism of heterogeneity progression. EXPERIMENTAL DESIGN Red fluorescence protein-tagged LNCaP cells were cocultured with green fluorescence protein-labeled prostate stromal cells for cancer-stromal cell fusion, which was tracked as dual fluorescent cells by fluorescence microscopy. RESULTS We identified the most efficient strategy to isolate clones of fusion hybrid progenies. From the coculture, mixed cells including fusion hybrids were subjected to low-density replating for colony formation by fusion hybrid progeny. These colonies could propagate into derivative cell populations. Compared to the parental LNCaP cells, clones of the fusion hybrid progeny displayed divergent behaviors and exhibited permanent genomic hybridization. CONCLUSIONS Cancer-stromal cell fusion leads to cancer cell heterogeneity. The cancer-stromal coculture system characterized in this study can be used as a model for molecular characterization of cancer cell fusion as the mechanism behind the progression of heterogeneity observed in clinical prostate cancers.
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Affiliation(s)
- Ruoxiang Wang
- Uro-Oncology Research, Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology, VA Greater Los Angeles Healthcare System, Los Angeles, CA
| | - Michael S. Lewis
- Uro-Oncology Research, Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology, VA Greater Los Angeles Healthcare System, Los Angeles, CA
| | - Ji Lyu
- Uro-Oncology Research, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Haiyen E. Zhau
- Uro-Oncology Research, Cedars-Sinai Medical Center, Los Angeles, CA
| | - Stephen J. Pandol
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA
- Department of Pathology, VA Greater Los Angeles Healthcare System, Los Angeles, CA
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20
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Fusion of macrophages promotes breast cancer cell proliferation, migration and invasion through activating epithelial-mesenchymal transition and Wnt/β-catenin signaling pathway. Arch Biochem Biophys 2019; 676:108137. [PMID: 31605677 DOI: 10.1016/j.abb.2019.108137] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 09/02/2019] [Accepted: 10/08/2019] [Indexed: 12/13/2022]
Abstract
Cell fusion is a highly regulated process involved in cancer development, tissue regeneration and other physiological and pathological events. Many studies have shown that cancer cells can fuse with different types of cells such as mesenchymal stem cells (MSCs) and macrophages, which are behaved as two important fusogenic candidates in the tumor microenvironment. However, the underlying mechanisms of cell fusion between macrophages and malignant cells in cancer progression has not been fully clarified. The aim of the present study was to investigate the effects and mechanisms of cell fusion between macrophages and breast cancer cells on tumorigenesis and metastasis. Our results indicated that the hybrids exhibited enhanced proliferation, colony formation, migration and invasion capabilities, as well as suppressed apoptosis compared with parental breast cancer cells. Moreover, the hybrid cells displayed EMT with a significant downregulation of E-cadherin and upregulation of N-cadherin, Vimentin and Snail, as well as an obviously increased expression of MMP-2, MMP-9, uPA and S100A4. Mechanistically, we found that the TCF/LEF transcription factor activity of Wnt/β-catenin pathway and the expression of its downstream target genes including cyclin D1 and c-Myc were increased in the hybrid cells. Furthermore, our data confirmed that the promoting effects of fusion of macrophages on breast cancer cell proliferation, migration and invasion could be blocked by treatment with XAV-939, a Wnt/β-catenin signaling pathway inhibitor. In conclusion, our findings demonstrate that fusion of macrophages promotes proliferation, migration and invasion of breast cancer cells through activating EMT and Wnt/β-catenin signaling pathway. Our current study will further contribute to elucidate the mechanism of cell fusion in tumorigenesis and metastasis, and to develop a new therapeutic strategy for breast cancer treatment.
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21
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Kim H, Nobeyama T, Honda S, Yasuda K, Morone N, Murakami T. Membrane fusogenic high-density lipoprotein nanoparticles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:183008. [PMID: 31207206 DOI: 10.1016/j.bbamem.2019.06.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/23/2019] [Accepted: 06/11/2019] [Indexed: 11/30/2022]
Abstract
Membrane fusion under mildly acidic pH occurs naturally during viral infection in cells and has been exploited in the field of nanoparticle-mediated drug delivery to circumvent endosomal entrapment of the cargo. Herein, we aimed to confer virus-like fusogenic activity to HDL in the form of a ca. 10-nm disc comprising a discoidal lipid bilayer and two copies of a lipid-binding protein at the edge. A series of HDL mutants were prepared with a mixture of three lipids and a cell-penetrating peptide (TAT, penetratin, or Arg8) fused to the protein. In a lipid-mixing assay with anionic liposomes at pH 5.5, one HDL mutant showed the fusogenic activity higher than known fusogenic liposomes. In live mammalian cells, this HDL mutant showed high plasma membrane-binding activity in the presence of serum independent of pH. In the absence of serum, a mildly acidic pH dependency for binding to the plasma membrane and the subsequent lipid mixing between them was observed for this mutant. We propose a novel strategy to develop HDL-based drug carriers by taking advantage of the HDL lipid/protein composite structure.
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Affiliation(s)
- Hyungjin Kim
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University Institute for Advanced Study (KUIAS), Sakyo-ku, Kyoto 606-8501, Japan
| | - Tomohiro Nobeyama
- Department of Biotechnology, Graduate School of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Shinnosuke Honda
- Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kaori Yasuda
- Department of Biotechnology, Graduate School of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan; Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan
| | - Nobuhiro Morone
- Medical Research Council Toxicology Unit, University of Cambridge, Leicester LE1 9HN, UK
| | - Tatsuya Murakami
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University Institute for Advanced Study (KUIAS), Sakyo-ku, Kyoto 606-8501, Japan; Department of Biotechnology, Graduate School of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan; Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, 5180 Kurokawa, Imizu, Toyama 939-0398, Japan.
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22
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Fei F, Li C, Wang X, Du J, Liu K, Li B, Yao P, Li Y, Zhang S. Syncytin 1, CD9, and CD47 regulating cell fusion to form PGCCs associated with cAMP/PKA and JNK signaling pathway. Cancer Med 2019; 8:3047-3058. [PMID: 31025548 PMCID: PMC6558479 DOI: 10.1002/cam4.2173] [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: 12/02/2018] [Accepted: 03/28/2019] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND We have previously reported the formation of polyploid giant cancer cells (PGCCs) through endoreduplication or cell fusion after cobalt chloride (CoCl2 ) induction. Cell fusion plays an important role in development and disease. However, the underlying molecular mechanism concerning cell fusion in PGCCs formation and clinicopathological significances remains unclear. METHODS We treat HCT116 and LoVo cell with CoCl2 and observed the cell fusion via fluorescent markers of different colors. Western blot and immunocytochemical staining were used to compare the expression and subcellular location of the fusion-related proteins syncytin 1, CD9, and CD47 along with PKA RIα, JNK1, and c-Jun between PGCCs and control cells from the HCT116 and LoVo cell lines. Moreover, 173 cases of colorectal tumor tissue samples were analyzed, including 47 cases of well-differentiated primary colorectal cancer (group I) and 5 cases of corresponding metastatic tumors (group II), 38 cases of moderately differentiated primary colorectal cancer (group III) and 14 cases of corresponding metastatic tumors (group IV), and 42 cases of poorly differentiated primary colorectal cancer (group V) and 27 cases of corresponding metastatic tumors (group VI). RESULTS The expression of syncytin 1, CD9, and CD47 is higher in PGCCs than in control cells and they are located in the cytoplasm. The expression of PKA RIα and JNK1 decreased, and that of c-Jun increased in PGCCs. The syncytin 1 expression was significantly different between groups I and II (P = 0.000), groups III and IV (P = 0.000), groups V and VI (P = 0.029), groups I and III (P = 0.001), groups III and V (P = 0.000), and groups I, III, and V (P = 0.000). CONCLUSIONS These data indicate that the cell fusion-related proteins syncytin 1, CD9, and CD47 may be involved in PGCC formation, and that cAMP/PKA and JNK signaling is likely to promote PGCC formation via the regulation of cell fusion processes.
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Affiliation(s)
- Fei Fei
- School of Medicine, Nankai University, Tianjin, P.R. China.,Department of Pathology, Tianjin Union Medical Center, Tianjin, P.R. China
| | - Chunyuan Li
- School of Medicine, Nankai University, Tianjin, P.R. China.,Department of Pathology, Tianjin Union Medical Center, Tianjin, P.R. China
| | - Xinlu Wang
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, P.R. China
| | - Jiaxing Du
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, P.R. China
| | - Kai Liu
- Tianjin Medical University, Tianjin, P.R. China
| | - Bo Li
- Graduate School, Tianjin University of Traditional Chinese Medicine, Tianjin, P.R. China
| | - Peiyu Yao
- Department of Pathology, Tianjin Union Medical Center, Tianjin, P.R. China
| | - Yuwei Li
- Department of colorectal surgery, Tianjin Union Medical Center, Tianjin, P.R. China
| | - Shiwu Zhang
- School of Medicine, Nankai University, Tianjin, P.R. China.,Department of Pathology, Tianjin Union Medical Center, Tianjin, P.R. China
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23
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Brukman NG, Uygur B, Podbilewicz B, Chernomordik LV. How cells fuse. J Cell Biol 2019; 218:1436-1451. [PMID: 30936162 PMCID: PMC6504885 DOI: 10.1083/jcb.201901017] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 12/11/2022] Open
Abstract
Brukman et al. review cell–cell fusion mechanisms, focusing on the identity of the fusogens that mediate these processes and the regulation of their activities. Cell–cell fusion remains the least understood type of membrane fusion process. However, the last few years have brought about major advances in understanding fusion between gametes, myoblasts, macrophages, trophoblasts, epithelial, cancer, and other cells in normal development and in diseases. While different cell fusion processes appear to proceed via similar membrane rearrangements, proteins that have been identified as necessary and sufficient for cell fusion (fusogens) use diverse mechanisms. Some fusions are controlled by a single fusogen; other fusions depend on several proteins that either work together throughout the fusion pathway or drive distinct stages. Furthermore, some fusions require fusogens to be present on both fusing membranes, and in other fusions, fusogens have to be on only one of the membranes. Remarkably, some of the proteins that fuse cells also sculpt single cells, repair neurons, promote scission of endocytic vesicles, and seal phagosomes. In this review, we discuss the properties and diversity of the known proteins mediating cell–cell fusion and highlight their different working mechanisms in various contexts.
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Affiliation(s)
- Nicolas G Brukman
- Department of Biology, Technion-Israel Institute of Technology, Haifa, Israel
| | - Berna Uygur
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | | | - Leonid V Chernomordik
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
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24
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Podolnikova NP, Hlavackova M, Wu Y, Yakubenko VP, Faust J, Balabiyev A, Wang X, Ugarova TP. Interaction between the integrin Mac-1 and signal regulatory protein α (SIRPα) mediates fusion in heterologous cells. J Biol Chem 2019; 294:7833-7849. [PMID: 30910815 DOI: 10.1074/jbc.ra118.006314] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 03/15/2019] [Indexed: 12/11/2022] Open
Abstract
Macrophage fusion leading to the formation of multinucleated giant cells is a hallmark of chronic inflammation. Several membrane proteins have been implicated in mediating cell-cell attachment during fusion, but their binding partners remain unknown. Recently, we demonstrated that interleukin-4 (IL-4)-induced fusion of mouse macrophages depends on the integrin macrophage antigen 1 (Mac-1). Surprisingly, the genetic deficiency of intercellular adhesion molecule 1 (ICAM-1), an established ligand of Mac-1, did not impair macrophage fusion, suggesting the involvement of other counter-receptors. Here, using various approaches, including signal regulatory protein α (SIRPα) knockdown, recombinant proteins, adhesion and fusion assays, biolayer interferometry, and peptide libraries, we show that SIRPα, which, similar to ICAM-1, belongs to the Ig superfamily and has previously been implicated in cell fusion, interacts with Mac-1. The following results support the conclusion that SIRPα is a ligand of Mac-1: (a) recombinant ectodomain of SIRPα supports adhesion of Mac-1-expressing cells; (b) Mac-1-SIRPα interaction is mediated through the ligand-binding αMI-domain of Mac-1; (c) recognition of SIRPα by the αMI-domain conforms to general principles governing binding of Mac-1 to many of its ligands; (d) SIRPα reportedly binds CD47; however, anti-CD47 function-blocking mAb produced only a limited inhibition of macrophage adhesion to SIRPα; and (e) co-culturing of SIRPα- and Mac-1-expressing HEK293 cells resulted in the formation of multinucleated cells. Taken together, these results identify SIRPα as a counter-receptor for Mac-1 and suggest that the Mac-1-SIRPα interaction may be involved in macrophage fusion.
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Affiliation(s)
- Nataly P Podolnikova
- From the Center for Metabolic and Vascular Biology, School of Life Sciences, and
| | - Marketa Hlavackova
- From the Center for Metabolic and Vascular Biology, School of Life Sciences, and
| | - Yifei Wu
- From the Center for Metabolic and Vascular Biology, School of Life Sciences, and
| | - Valentin P Yakubenko
- the College of Medicine, East Tennessee State University, Johnson City, Tennessee 37614
| | - James Faust
- From the Center for Metabolic and Vascular Biology, School of Life Sciences, and
| | - Arnat Balabiyev
- From the Center for Metabolic and Vascular Biology, School of Life Sciences, and
| | - Xu Wang
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287 and
| | - Tatiana P Ugarova
- From the Center for Metabolic and Vascular Biology, School of Life Sciences, and
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25
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Chuang MC, Lin SS, Ohniwa RL, Lee GH, Su YA, Chang YC, Tang MJ, Liu YW. Tks5 and Dynamin-2 enhance actin bundle rigidity in invadosomes to promote myoblast fusion. J Cell Biol 2019; 218:1670-1685. [PMID: 30894403 PMCID: PMC6504888 DOI: 10.1083/jcb.201809161] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/22/2019] [Accepted: 03/04/2019] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle development requires the cell-cell fusion of differentiated myoblasts to form muscle fibers. The actin cytoskeleton is known to be the main driving force for myoblast fusion; however, how actin is organized to direct intercellular fusion remains unclear. Here we show that an actin- and dynamin-2-enriched protrusive structure, the invadosome, is required for the fusion process of myogenesis. Upon differentiation, myoblasts acquire the ability to form invadosomes through isoform switching of a critical invadosome scaffold protein, Tks5. Tks5 directly interacts with and recruits dynamin-2 to the invadosome and regulates its assembly around actin filaments to strengthen the stiffness of dynamin-actin bundles and invadosomes. These findings provide a mechanistic framework for the acquisition of myogenic fusion machinery during myogenesis and reveal a novel structural function for Tks5 and dynamin-2 in organizing actin filaments in the invadosome to drive membrane fusion.
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Affiliation(s)
- Mei-Chun Chuang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Shan-Shan Lin
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ryosuke L Ohniwa
- Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.,Center for Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Gang-Hui Lee
- International Center of Wound Repair and Regeneration, National Cheng Kung University, Tainan, Taiwan
| | - You-An Su
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yu-Chen Chang
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ming-Jer Tang
- International Center of Wound Repair and Regeneration, National Cheng Kung University, Tainan, Taiwan.,Department of Physiology, Medical College, National Cheng Kung University, Tainan, Taiwan
| | - Ya-Wen Liu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan .,Center of Precision Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
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26
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Liu Y, Fan X, Wang R, Lu X, Dang YL, Wang H, Lin HY, Zhu C, Ge H, Cross JC, Wang H. Single-cell RNA-seq reveals the diversity of trophoblast subtypes and patterns of differentiation in the human placenta. Cell Res 2018; 28:819-832. [PMID: 30042384 PMCID: PMC6082907 DOI: 10.1038/s41422-018-0066-y] [Citation(s) in RCA: 230] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 06/13/2018] [Accepted: 06/20/2018] [Indexed: 12/12/2022] Open
Abstract
The placenta is crucial for a successful pregnancy and the health of both the fetus and the pregnant woman. However, how the human trophoblast lineage is regulated, including the categorization of the placental cell subtypes is poorly understood. Here we performed single-cell RNA sequencing (RNA-seq) on sorted placental cells from first- and second-trimester human placentas. New subtypes of cells of the known cytotrophoblast cells (CTBs), extravillous trophoblast cells (EVTs), Hofbauer cells, and mesenchymal stromal cells were identified and cell-type-specific gene signatures were defined. Functionally, this study revealed many previously unknown functions of the human placenta. Notably, 102 polypeptide hormone genes were found to be expressed by various subtypes of placental cells, which suggests a complex and significant role of these hormones in regulating fetal growth and adaptations of maternal physiology to pregnancy. These results document human placental trophoblast differentiation at single-cell resolution and thus advance our understanding of human placentation during the early stage of pregnancy.
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Affiliation(s)
- Yawei Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China
| | - Xiaoying Fan
- Biomedical Pioneering Innovation Center, College of Life Science, Peking University, 100871, Beijing, China
| | - Rui Wang
- Biomedical Pioneering Innovation Center, College of Life Science, Peking University, 100871, Beijing, China
| | - Xiaoyin Lu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China.,Department of Experimental Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Yan-Li Dang
- Department of Obstetrics and Gynecology, The 306th Hospital of PLA, 100101, Beijing, China
| | - Huiying Wang
- Department of Obstetrics and Gynecology, Beijing Shijitan Hospital, 100038, Beijing, China
| | - Hai-Yan Lin
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China
| | - Cheng Zhu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China
| | - Hao Ge
- Biomedical Pioneering Innovation Center, College of Life Science, Peking University, 100871, Beijing, China
| | - James C Cross
- Departments of Biochemistry and Molecular Biology, Comparative Biology and Experimental Medicine, Obstetrics and Gynecology, and Medical Genetics, University of Calgary, Calgary, AB, T2N 4N1, Canada.
| | - Hongmei Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101, Beijing, China.
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27
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Ezrin-anchored PKA phosphorylates serine 369 and 373 on connexin 43 to enhance gap junction assembly, communication, and cell fusion. Biochem J 2018; 475:455-476. [PMID: 29259079 DOI: 10.1042/bcj20170529] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 12/14/2017] [Accepted: 12/15/2017] [Indexed: 12/25/2022]
Abstract
A limited number of human cells can fuse to form multinucleated syncytia. In the differentiation of human placenta, mononuclear cytotrophoblasts fuse to form an endocrinologically active, non-proliferative, multinucleated syncytium. This syncytium covers the placenta and manages the exchange of nutrients and gases between maternal and fetal circulation. We recently reported protein kinase A (PKA) to be part of a macromolecular signaling complex with ezrin and gap junction protein connexin 43 (Cx43) that provides cAMP-mediated control of gap junction communication. Here, we examined the associated phosphorylation events. Inhibition of PKA activity resulted in decreased Cx43 phosphorylation, which was associated with reduced trophoblast fusion and differentiation. In vitro studies using peptide arrays, together with mass spectrometry, pointed to serine 369 and 373 of Cx43 as the major PKA phosphorylation sites that increases gap junction assembly at the plasmalemma. A combination of knockdown and reconstitution experiments and gap-fluorescence loss in photobleaching assays with mutant Cx43 containing single or double phosphoserine-mimicking amino acid substitutions in putative PKA phosphorylation sites demonstrated that phosphorylation of S369 and S373 mediated gap junction communication, trophoblast differentiation, and cell fusion.
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28
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Abstract
Cell-cell fusion is essential for fertilization and organ development. Dedicated proteins known as fusogens are responsible for mediating membrane fusion. However, until recently, these proteins either remained unidentified or were poorly understood at the mechanistic level. Here, we review how fusogens surmount multiple energy barriers to mediate cell-cell fusion. We describe how early preparatory steps bring membranes to a distance of ∼10 nm, while fusogens act in the final approach between membranes. The mechanical force exerted by cell fusogens and the accompanying lipidic rearrangements constitute the hallmarks of cell-cell fusion. Finally, we discuss the relationship between viral and eukaryotic fusogens, highlight a classification scheme regrouping a superfamily of fusogens called Fusexins, and propose new questions and avenues of enquiry.
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Affiliation(s)
- Javier M Hernández
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, D-44227 Dortmund, Germany
| | - Benjamin Podbilewicz
- Department of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel
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29
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Wiseman E, Bates L, Dubé A, Carroll DJ. Starfish as a Model System for Analyzing Signal Transduction During Fertilization. Results Probl Cell Differ 2018; 65:49-67. [PMID: 30083915 DOI: 10.1007/978-3-319-92486-1_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2023]
Abstract
The starfish oocyte and egg offer advantages for use as a model system for signal transduction research. Some of these have been recognized for over a century, including the ease of procuring gametes, in vitro fertilization, and culturing the embryos. New advances, particularly in genomics, have also opened up opportunities for the use of these animals. In this chapter, we give a few examples of the historical use of the starfish for research in cell biology and then describe some new areas in which we believe the starfish can contribute to our understanding of signal transduction-particularly in fertilization.
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Affiliation(s)
- Emily Wiseman
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Lauren Bates
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - Altair Dubé
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - David J Carroll
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, USA.
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30
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A Cell Fusion-Based Screening Method Identifies Glycosylphosphatidylinositol-Anchored Protein Ly6e as the Receptor for Mouse Endogenous Retroviral Envelope Syncytin-A. J Virol 2017; 91:JVI.00832-17. [PMID: 28679758 DOI: 10.1128/jvi.00832-17] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 06/28/2017] [Indexed: 11/20/2022] Open
Abstract
Syncytin genes are envelope genes of retroviral origin that have been exapted for a role in placentation. They are involved in the formation of a syncytial structure (the syncytiotrophoblast) at the fetomaternal interface via their fusogenic activity. The mouse placenta is unique among placental mammals since the fetomaternal interface comprises two syncytiotrophoblast layers (ST-I and ST-II) instead of one, as observed in humans and all other hemochorial placentae. Each layer specifically expresses a distinct mouse syncytin, namely, syncytin-A (SynA) for ST-I and syncytin-B (SynB) for ST-II, which have been shown to be essential to placentogenesis and embryo survival. Their cognate cellular receptors, which are necessary to mediate cell-cell fusion and syncytiotrophoblast formation, are still unknown. By devising a sensitive method that combines a cell-cell fusion assay with the screening of a mouse cDNA library, we succeeded in identifying the glycosylphosphatidylinositol (GPI)-anchored membrane protein lymphocyte antigen 6E (Ly6e) as a candidate receptor for SynA. Transfection of cells with the cloned receptor led to their fusion to cells expressing SynA, with no cross-reactive fusion activity with SynB. Knocking down Ly6e greatly reduced SynA-induced cell fusion, thus suggesting that Ly6e is the sole receptor for SynA in vivo Interaction of SynA with Ly6e was further demonstrated by a competition assay using the soluble ectodomain of Ly6e. Finally, reverse transcription-quantitative PCR (RT-qPCR) analysis of Ly6e expression on a representative panel of mouse tissues shows that it is significantly expressed in the mouse placenta together with SynA.IMPORTANCE Syncytin genes are envelope genes of endogenous retroviruses, co-opted for a physiological function in placentation. Syncytins are fusogenic proteins that mediate cell-cell fusion by interacting with receptors present on the partner cells. Here, by devising a sensitive in vitro fusion assay that enables the high-throughput screening of normalized cDNA libraries, we identified the long-sought receptor for syncytin-A (SynA), a mouse syncytin responsible for syncytiotrophoblast formation at the maternofetal interface of the mouse placenta. This protein, Ly6e (lymphocyte antigen 6E), is a GPI-anchored membrane protein, and small interfering RNA (siRNA) experiments targeting its deletion as well as a decoy assay using a recombinant soluble receptor show that Ly6e is the necessary and sufficient partner of SynA. Its profile of expression is consistent with a role in both ancestral endogenization of a SynA founder retrovirus and present-day placenta formation. This study provides a powerful general method to identify genes involved in cell-cell fusion processes.
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31
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Napier S. Identifying organisms. LINACRE QUARTERLY 2017; 84:145-154. [PMID: 28698707 DOI: 10.1080/00243639.2017.1306678] [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: 10/19/2022]
Abstract
Defenders of human, embryonic, destructive stem-cell research and early abortion typically argue for their position by showing that you and I do not come into existence at conception but rather at some point after. Eugene Mills has provided an ingenious argument that you and I could not have come into existence at conception. I argue against Mills's argument on two counts: first, his argument depends upon a cursory limning of human conception, and when fuller details are considered, a premise in his argument is undercut. Second, Mills's argument invites us to ask questions about how to identify individual organisms. Given a fuller description of human conception and some plausible metaphysical principles, I argue that Mills should hold instead that you and I do in fact come into being at conception. SUMMARY One way to argue that early abortions are permissible is to argue against the view that you and I come into existence at conception. Most abortion rights defenders argue for this conclusion by noting that in order for you and I to exist, there must be developed psychological capacities. Eugene Mills takes a different route and argues that you and I could not come into existence at conception because that would mean being identical to an egg - which he rightly notes we cannot be. I argue against Mills in this article.
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Affiliation(s)
- Stephen Napier
- Philosophy Department, Villanova University, Villanova, PA, USA
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32
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Savić F, Kliesch TT, Verbeek S, Bao C, Thiart J, Kros A, Geil B, Janshoff A. Geometry of the Contact Zone between Fused Membrane-Coated Beads Mimicking Cell-Cell Fusion. Biophys J 2017; 110:2216-28. [PMID: 27224487 DOI: 10.1016/j.bpj.2016.04.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/06/2016] [Accepted: 04/20/2016] [Indexed: 01/20/2023] Open
Abstract
The fusion of lipid membranes is a key process in biology. It enables cells and organelles to exchange molecules with their surroundings, which otherwise could not cross the membrane barrier. To study such complex processes we use simplified artificial model systems, i.e., an optical fusion assay based on membrane-coated glass spheres. We present a technique to analyze membrane-membrane interactions in a large ensemble of particles. Detailed information on the geometry of the fusion stalk of fully fused membranes is obtained by studying the diffusional lipid dynamics with fluorescence recovery after photobleaching experiments. A small contact zone is a strong obstruction for the particle exchange across the fusion spot. With the aid of computer simulations, fluorescence-recovery-after-photobleaching recovery times of both fused and single-membrane-coated beads allow us to estimate the size of the contact zones between two membrane-coated beads. Minimizing delamination and bending energy leads to minimal angles close to those geometrically allowed.
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Affiliation(s)
- Filip Savić
- Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany
| | | | - Sarah Verbeek
- Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany
| | - Chunxiao Bao
- Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany
| | - Jan Thiart
- Drittes Physikalisches Institut, Georg-August-Universität, Göttingen, Germany
| | - Alexander Kros
- Leiden Institute of Chemistry, Universiteit Leiden, Leiden, The Netherlands
| | - Burkhard Geil
- Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany.
| | - Andreas Janshoff
- Institut für Physikalische Chemie, Georg-August-Universität, Göttingen, Germany.
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33
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Essential Roles of L-Type Amino Acid Transporter 1 in Syncytiotrophoblast Development by Presenting Fusogenic 4F2hc. Mol Cell Biol 2017; 37:MCB.00427-16. [PMID: 28320871 DOI: 10.1128/mcb.00427-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 03/09/2017] [Indexed: 01/30/2023] Open
Abstract
The layers of the epithelial syncytium, i.e., syncytiotrophoblasts, differentiate from chorionic trophoblasts via cell fusion and separate maternal and fetal circulations in hemochorial placentas. L-type amino acid transporter 1 (LAT1) and its covalently linked ancillary subunit 4F2hc are colocalized on both maternal and fetal surfaces of syncytiotrophoblasts, implying their roles in amino acid transfer through the placental barrier. In this study, LAT1 knockout, in addition, revealed a novel role of LAT1 in syncytiotrophoblast development. LAT1 at midgestation was selectively expressed in trophoblastic lineages in the placenta, exclusively as a LAT1-4F2hc heterodimer. In LAT1 homozygous knockout mice, chorionic trophoblasts remained largely mononucleated, and the layers of syncytiotrophoblasts were almost completely absent. The amount of 4F2hc protein, which possesses a fusogenic function in trophoblastic cells, as well as in virus-infected cells, was drastically reduced by LAT1 knockout, with less affecting the mRNA level. Knockdown of LAT1 in trophoblastic BeWo cells also reduced 4F2hc protein and suppressed forskolin-induced cell fusion. These results demonstrate a novel fundamental role of LAT1 to support the protein expression of 4F2hc via a chaperone-like function in chorionic trophoblasts and to promote syncytiotrophoblast formation by contributing to cell fusion in the developing placenta.
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34
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Phosphatidylethanolamine dynamics are required for osteoclast fusion. Sci Rep 2017; 7:46715. [PMID: 28436434 PMCID: PMC5402267 DOI: 10.1038/srep46715] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 03/23/2017] [Indexed: 11/08/2022] Open
Abstract
Osteoclasts, responsible for bone resorption, are multinucleated cells formed by cell-cell fusion of mononuclear pre-osteoclasts. Although osteoclast fusion is a pivotal step for osteoclastogenesis, little is known about the mechanism involved. To clarify the underlying process, we investigated dynamics of membrane phospholipids during osteoclastogenesis in vitro. We found that the cellular content of phospholipids, phosphatidylethanolamine (PE) in particular, was increased during osteoclast differentiation. Furthermore, PE was greatly increased in the outer leaflet of the plasma membrane bilayer during osteoclastogenesis, being concentrated in filopodia involved in cell-cell fusion. Immobilisation of the cell surface PE blocked osteoclast fusion, revealing the importance of PE abundance and distribution. To identify the molecules responsible for these PE dynamics, we screened a wide array of lipid-related genes by quantitative PCR and shRNA-mediated knockdown. Among them, a PE-biosynthetic enzyme, acyl-CoA:lysophosphatidylethanolamine acyltransferase 2 (LPEAT2), and two ATP-binding cassette (ABC) transporters, ABCB4 and ABCG1, were markedly increased during osteoclastogenesis, and their knockdown in pre-osteoclasts led to reduction in PE exposure on the cell surface and subsequent osteoclast fusion. These findings demonstrate that the PE dynamics play an essential role in osteoclast fusion, in which LPEAT2, ABCB4 and ABCG1 are key players for PE biosynthesis and redistribution.
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Degrelle SA, Gerbaud P, Leconte L, Ferreira F, Pidoux G. Annexin-A5 organized in 2D-network at the plasmalemma eases human trophoblast fusion. Sci Rep 2017; 7:42173. [PMID: 28176826 PMCID: PMC5297248 DOI: 10.1038/srep42173] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/30/2016] [Indexed: 12/13/2022] Open
Abstract
Only a limited number of human cells can fuse to form a multinucleated syncytium. Cell fusion occurs as part of the differentiation of some cell types, including myotubes in muscle and osteoclasts in remodeling bone. In the differentiation of the human placenta, mononuclear cytotrophoblasts aggregate and fuse to form endocrinologically active, non-proliferative, multinucleated syncytia. These syncytia allow the exchange of nutrients and gases between the maternal and fetal circulation. Alteration of syncytial formation during pregnancy affects fetal growth and the outcome of the pregnancy. Here, we demonstrate the role of annexin A5 (AnxA5) in syncytial formation by cellular delivery of recombinant AnxA5 and RNA interference. By a variety of co-immunoprecipitation, immunolocalization and proximity experiments, we show that a pool of AnxA5 organizes at the inner-leaflet of the plasma membrane in the vicinity of a molecular complex that includes E-Cadherin, α-Catenin and β-Catenin, three proteins previously shown to form adherens junctions implicated in cell fusion. A combination of knockdown and reconstitution experiments with AnxA5, with or without the ability to self-assemble in 2D-arrays, demonstrate that this AnxA5 2D-network mediates E-Cadherin mobility in the plasmalemma that triggers human trophoblasts aggregation and thereby cell fusion.
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Affiliation(s)
- Severine A Degrelle
- INSERM, U767, Cell fusion, Paris, F-75006 France.,Université Paris Descartes, Paris, F-75006 France.,PremUp, Paris, F-75006 France
| | - Pascale Gerbaud
- INSERM, U767, Cell fusion, Paris, F-75006 France.,Université Paris Descartes, Paris, F-75006 France.,UMR-S1180, Inserm, Univ. Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
| | - Ludovic Leconte
- UMR144, Institut Curie/CNRS, Cell and Tissue Imaging Platform, Paris, France
| | - Fatima Ferreira
- INSERM, U767, Cell fusion, Paris, F-75006 France.,Université Paris Descartes, Paris, F-75006 France
| | - Guillaume Pidoux
- INSERM, U767, Cell fusion, Paris, F-75006 France.,Université Paris Descartes, Paris, F-75006 France.,PremUp, Paris, F-75006 France.,UMR-S1180, Inserm, Univ. Paris-Sud, Université Paris-Saclay, Châtenay-Malabry, France
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Abstract
Cell-cell fusion is fundamental to a multitude of biological processes ranging from cell differentiation and embryogenesis to cancer metastasis and biomaterial-tissue interactions. Fusogenic cells are exposed to biochemical and biophysical factors, which could potentially alter cell behavior. While biochemical inducers of fusion such as cytokines and kinases have been identified, little is known about the biophysical regulation of cell-cell fusion. Here, we designed experiments to examine cell-cell fusion using bulk metallic glass (BMG) nanorod arrays with varying biophysical cues, i.e. nanotopography and stiffness. Through independent variation of stiffness and topography, we found that nanotopography constitutes the primary biophysical cue that can override biochemical signals to attenuate fusion. Specifically, nanotopography restricts cytoskeletal remodeling-associated signaling, which leads to reduced fusion. This finding expands our fundamental understanding of the nanoscale biophysical regulation of cell fusion and can be exploited in biomaterials design to induce desirable biomaterial-tissue interactions.
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Platt JL, Zhou X, Lefferts AR, Cascalho M. Cell Fusion in the War on Cancer: A Perspective on the Inception of Malignancy. Int J Mol Sci 2016; 17:E1118. [PMID: 27420051 PMCID: PMC4964493 DOI: 10.3390/ijms17071118] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/28/2016] [Accepted: 07/07/2016] [Indexed: 12/11/2022] Open
Abstract
Cell fusion occurs in development and in physiology and rarely in those settings is it associated with malignancy. However, deliberate fusion of cells and possibly untoward fusion of cells not suitably poised can eventuate in aneuploidy, DNA damage and malignant transformation. How often cell fusion may initiate malignancy is unknown. However, cell fusion could explain the high frequency of cancers in tissues with low underlying rates of cell proliferation and mutation. On the other hand, cell fusion might also engage innate and adaptive immune surveillance, thus helping to eliminate or retard malignancies. Here we consider whether and how cell fusion might weigh on the overall burden of cancer in modern societies.
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Affiliation(s)
- Jeffrey L Platt
- Departments of Surgery and of Microbiology & Immunology, University of Michigan, A520B Medical Sciences Research Building I, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-5656, USA.
| | - Xiaofeng Zhou
- Departments of Surgery and of Microbiology & Immunology, University of Michigan, A520B Medical Sciences Research Building I, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-5656, USA.
| | - Adam R Lefferts
- Departments of Surgery and of Microbiology & Immunology, University of Michigan, A520B Medical Sciences Research Building I, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-5656, USA.
| | - Marilia Cascalho
- Departments of Surgery and of Microbiology & Immunology, University of Michigan, A520B Medical Sciences Research Building I, 1150 W. Medical Center Drive, Ann Arbor, MI 48109-5656, USA.
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The Role of Integrins αMβ2 (Mac-1, CD11b/CD18) and αDβ2 (CD11d/CD18) in Macrophage Fusion. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2105-2116. [PMID: 27315778 DOI: 10.1016/j.ajpath.2016.04.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 03/11/2016] [Accepted: 04/06/2016] [Indexed: 11/22/2022]
Abstract
The subfamily of β2 integrins is implicated in macrophage fusion, a hallmark of chronic inflammation. Among β2 family members, integrin Mac-1 (αMβ2, CD11b/CD18) is abundantly expressed on monocyte/macrophages and mediates critical adhesive reactions of these cells. However, the role of Mac-1 in macrophage fusion leading to the formation of multinucleated giant cells remains unclear. Moreover, the role of integrin αDβ2 (CD11d/CD18), a receptor with recognition specificity overlapping that of Mac-1, is unknown. We found that multinucleated giant cells are formed in the inflamed mouse peritoneum during the resolution phase of inflammation, and their numbers were approximately twofold higher in wild-type mice than in Mac-1(-/-) mice. Analyses of isolated inflammatory peritoneal macrophages showed that IL-4-induced fusion of Mac-1-deficient cells was strongly reduced compared with wild-type counterparts. The examination of adhesive reactions known to be required for fusion showed that spreading, but not adhesion and migration, was reduced in Mac-1-deficient macrophages. Fusion of αDβ2-deficient macrophages was also significantly decreased, albeit to a smaller degree. Deficiency of intercellular adhesion molecule 1, a counter-receptor for Mac-1 and αDβ2, did not alter the fusion rate. The results indicate that both Mac-1 and αDβ2 support macrophage fusion with Mac-1 playing a dominant role and suggest that Mac-1 may mediate cell-cell interactions with a previously unrecognized counter-receptor(s).
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Yan B, Wang J, Liu L. Chemotherapy promotes tumour cell hybridization in vivo. Tumour Biol 2016; 37:5025-30. [PMID: 26537586 PMCID: PMC4844647 DOI: 10.1007/s13277-015-4337-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 10/28/2015] [Indexed: 01/06/2023] Open
Abstract
Spontaneous cell-cell fusion has been recognized to be an important mechanism for tissue and organ development and repair. In cancer, cell fusion is critically involved in tumourigenesis, metastasis and drug resistance, as illustrated by in vitro experiments. However, there has been no direct detection of tumour cell fusion or hybridization in an in vivo tumour environment, and the features of hybridized cells under selective pressures, such as chemotherapy, are unknown. Here, we expressed two fluorescent marker proteins in the human breast cancer cell line SKBR3 to detect tumour cell hybridization in vivo and performed a xenograft chemotherapy experiment in mice to evaluate the chemotherapeutic response of the hybrids. The mice treated by epirubicin showed that chemotherapy promoted tumour cell hybridization in vivo, which elicited the production of more hybrids in the outer section of the tumour. These results provide the first in vivo evidence of tumour cell fusion and indicate that chemotherapy may contribute to a poor prognosis by enriching for fused cells, which are more malignant. It is therefore necessary to reassess chemotherapy strategies.
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Affiliation(s)
- Bingyu Yan
- State Key Laboratory of Biocontrol, College of Ecology and Evolution, Sun Yat-sen University, #135 Xinggang West, Guangzhou, 510275, China
| | - Jianguo Wang
- State Key Laboratory of Biocontrol, College of Ecology and Evolution, Sun Yat-sen University, #135 Xinggang West, Guangzhou, 510275, China
| | - Li Liu
- State Key Laboratory of Biocontrol, College of Ecology and Evolution, Sun Yat-sen University, #135 Xinggang West, Guangzhou, 510275, China.
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Shinn-Thomas JH, del Campo JJ, Wang J, Mohler WA. The EFF-1A Cytoplasmic Domain Influences Hypodermal Cell Fusions in C. elegans But Is Not Dependent on 14-3-3 Proteins. PLoS One 2016; 11:e0146874. [PMID: 26800457 PMCID: PMC4723337 DOI: 10.1371/journal.pone.0146874] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/25/2015] [Indexed: 12/19/2022] Open
Abstract
Background Regulatory and biophysical mechanisms of cell-cell fusion are largely unknown despite the fundamental requirement for fused cells in eukaryotic development. Only two cellular fusogens that are not of clear recent viral origin have been identified to date, both in nematodes. One of these, EFF-1, is necessary for most cell fusions in Caenorhabditis elegans. Unregulated EFF-1 expression causes lethality due to ectopic fusion between cells not developmentally programmed to fuse, highlighting the necessity of tight fusogen regulation for proper development. Identifying factors that regulate EFF-1 and its paralog AFF-1 could lead to discovery of molecular mechanisms that control cell fusion upstream of the action of a membrane fusogen. Bioinformatic analysis of the EFF-1A isoform’s predicted cytoplasmic domain (endodomain) previously revealed two motifs that have high probabilities of interacting with 14-3-3 proteins when phosphorylated. Mutation of predicted phosphorylation sites within these motifs caused measurable loss of eff-1 gene function in cell fusion in vivo. Moreover, a human 14-3-3 isoform bound to EFF-1::GFP in vitro. We hypothesized that the two 14-3-3 proteins in C. elegans, PAR-5 and FTT-2, may regulate either localization or fusion-inducing activity of EFF-1. Methodology/Principal Findings Timing of fusion events was slightly but significantly delayed in animals unable to produce full-length EFF-1A. Yet, mutagenesis and live imaging showed that phosphoserines in putative 14-3-3 binding sites are not essential for EFF-1::GFP accumulation at the membrane contact between fusion partner cells. Moreover, although the EFF-1A endodomain was required for normal rates of eff-1-dependent epidermal cell fusions, reduced levels of FTT-2 and PAR-5 did not visibly affect the function of wild-type EFF-1 in the hypodermis. Conclusions/Significance Deletion of the EFF-1A endodomain noticeably affects the timing of hypodermal cell fusions in vivo. However, prohibiting phosphorylation of candidate 14-3-3-binding sites does not impact localization of the fusogen. Hypodermal membrane fusion activity persists when 14-3-3 expression levels are reduced.
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Affiliation(s)
- Jessica H. Shinn-Thomas
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, MC-6403, 263 Farmington Avenue, Farmington, CT 06030–6403, United States of America
- * E-mail: (WAM); (JHST)
| | - Jacob J. del Campo
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, MC-6403, 263 Farmington Avenue, Farmington, CT 06030–6403, United States of America
| | - Jianjun Wang
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, MC-6403, 263 Farmington Avenue, Farmington, CT 06030–6403, United States of America
| | - William A. Mohler
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, MC-6403, 263 Farmington Avenue, Farmington, CT 06030–6403, United States of America
- * E-mail: (WAM); (JHST)
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41
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Takegahara N, Kim H, Mizuno H, Sakaue-Sawano A, Miyawaki A, Tomura M, Kanagawa O, Ishii M, Choi Y. Involvement of Receptor Activator of Nuclear Factor-κB Ligand (RANKL)-induced Incomplete Cytokinesis in the Polyploidization of Osteoclasts. J Biol Chem 2015; 291:3439-54. [PMID: 26670608 PMCID: PMC4751386 DOI: 10.1074/jbc.m115.677427] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Indexed: 12/21/2022] Open
Abstract
Osteoclasts are specialized polyploid cells that resorb bone. Upon stimulation with receptor activator of nuclear factor-κB ligand (RANKL), myeloid precursors commit to becoming polyploid, largely via cell fusion. Polyploidization of osteoclasts is necessary for their bone-resorbing activity, but the mechanisms by which polyploidization is controlled remain to be determined. Here, we demonstrated that in addition to cell fusion, incomplete cytokinesis also plays a role in osteoclast polyploidization. In in vitro cultured osteoclasts derived from mice expressing the fluorescent ubiquitin-based cell cycle indicator (Fucci), RANKL induced polyploidy by incomplete cytokinesis as well as cell fusion. Polyploid cells generated by incomplete cytokinesis had the potential to subsequently undergo cell fusion. Nuclear polyploidy was also observed in osteoclasts in vivo, suggesting the involvement of incomplete cytokinesis in physiological polyploidization. Furthermore, RANKL-induced incomplete cytokinesis was reduced by inhibition of Akt, resulting in impaired multinucleated osteoclast formation. Taken together, these results reveal that RANKL-induced incomplete cytokinesis contributes to polyploidization of osteoclasts via Akt activation.
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Affiliation(s)
- Noriko Takegahara
- From the Next Generation Optical Immune-imaging, WPI-Immunology Frontier Research Center, Osaka University, Suita, Osaka 565-0871, Japan, the Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104,
| | - Hyunsoo Kim
- the Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Hiroki Mizuno
- the Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, WPI-Immunology Frontier Research Center, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan, the CREST, Japan Science and Technology Agency, 5 Sanban-cho, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Asako Sakaue-Sawano
- the Laboratory for Cell Function and Dynamics, Advanced Technology Development Group, Brain Science Institute, RIKEN, Wako-city, Saitama 351-0198, Japan
| | - Atsushi Miyawaki
- the Laboratory for Cell Function and Dynamics, Advanced Technology Development Group, Brain Science Institute, RIKEN, Wako-city, Saitama 351-0198, Japan
| | - Michio Tomura
- the Laboratory for Autoimmune Regulation, Research Center for Allergy and Immunology, RIKEN, Yokohama City, Kanagawa 230-0045, Japan, the Laboratory of Immunology, Faculty of Pharmacy, Osaka-Ohtani University, 3-11-1 Nishikiorikita, Tondabayashi-city, Osaka 584-8540, Japan, and
| | - Osami Kanagawa
- the Department of Molecular Preventive Medicine, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-033, Japan
| | - Masaru Ishii
- the Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, WPI-Immunology Frontier Research Center, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan, the CREST, Japan Science and Technology Agency, 5 Sanban-cho, Chiyoda-ku, Tokyo 102-0075, Japan
| | - Yongwon Choi
- the Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104,
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Macri KM, Noonan PS, Schwartz DK. Receptor-Mediated Liposome Fusion Kinetics at Aqueous/Liquid Crystal Interfaces. ACS APPLIED MATERIALS & INTERFACES 2015; 7:20400-20409. [PMID: 26317496 DOI: 10.1021/acsami.5b06351] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Membrane fusion events are essential to cell biology, and a number of reductionist systems have been developed to mimic the behavior of these biological motifs. One such system monitors the DNA hybridization-mediated fusion of liposomes with the liquid crystal (LC) interface by observing changes in LC orientation using a simple optical detection scheme. We have systematically explored key parameters of this system to determine their effects on individual elementary steps of the complex fusion mechanism. The liposome composition, specifically the degree of lipid unsaturation and PE content, decreased the bilayer rigidity, thereby increasing the rate of vesicle rupture under the stress applied by DNA hybridization. In contrast, the presence of cholesterol had the opposite effect on the mechanical properties of the bilayer, and hence of the membrane fusion rates. The accessibility of receptor moieties (i.e., complementary DNA oligonucleotides) affected the fusion kinetics by modulating the rate of hybridization events. DNA accessibility was controlled by systematic variation of the length of the DNA receptor molecules and the thickness of the steric barrier comprised of adsorbed PEGylated lipids. These results provide design rules for understanding the trade-offs between response kinetics and other important system properties, such as nonspecific adsorption. Moreover, these findings improve our understanding of the biophysical properties of membrane fusion, an important process in both natural and model systems used for bioassay and bioimaging applications.
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Affiliation(s)
- Katherine M Macri
- Department of Chemical and Biological Engineering, University of Colorado Boulder , Boulder, Colorado 80309-0596, United States
| | - Patrick S Noonan
- Department of Chemical and Biological Engineering, University of Colorado Boulder , Boulder, Colorado 80309-0596, United States
| | - Daniel K Schwartz
- Department of Chemical and Biological Engineering, University of Colorado Boulder , Boulder, Colorado 80309-0596, United States
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43
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Gerbaud P, Taskén K, Pidoux G. Spatiotemporal regulation of cAMP signaling controls the human trophoblast fusion. Front Pharmacol 2015; 6:202. [PMID: 26441659 PMCID: PMC4569887 DOI: 10.3389/fphar.2015.00202] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 09/02/2015] [Indexed: 01/01/2023] Open
Abstract
During human placentation, mononuclear cytotrophoblasts fuse to form multinucleated syncytia ensuring hormonal production and nutrient exchanges between the maternal and fetal circulation. Syncytial formation is essential for the maintenance of pregnancy and for fetal growth. The cAMP signaling pathway is the major route to trigger trophoblast fusion and its activation results in phosphorylation of specific intracellular target proteins, in transcription of fusogenic genes and assembly of macromolecular protein complexes constituting the fusogenic machinery at the plasma membrane. Specificity in cAMP signaling is ensured by generation of localized pools of cAMP controlled by cAMP phosphodiesterases (PDEs) and by discrete spatial and temporal activation of protein kinase A (PKA) in supramolecular signaling clusters inside the cell organized by A-kinase-anchoring proteins (AKAPs) and by organization of signal termination by protein phosphatases (PPs). Here we present original observations on the available components of the cAMP signaling pathway in the human placenta including PKA, PDE, and PP isoforms as well as AKAPs. We continue to discuss the current knowledge of the spatiotemporal regulation of cAMP signaling triggering trophoblast fusion.
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Affiliation(s)
- Pascale Gerbaud
- INSERM, UMR-S-1139, Group Cell Fusion, Université Paris Descartes Paris, France ; Université Paris Descartes Paris, France
| | - Kjetil Taskén
- Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo and Oslo University Hospital Oslo, Norway ; Biotechnology Centre, University of Oslo Oslo, Norway ; K.G. Jebsen Inflammation Research Centre, University of Oslo Oslo, Norway ; K.G. Jebsen Centre for Cancer Immunotherapy, University of Oslo Oslo, Norway ; Department of Infectious Diseases, Oslo University Hospital Oslo, Norway
| | - Guillaume Pidoux
- INSERM, UMR-S-1139, Group Cell Fusion, Université Paris Descartes Paris, France ; Université Paris Descartes Paris, France ; INSERM, U1180 Châtenay-Malabry, France ; Faculté de Pharmacie, Université Paris-Sud Châtenay-Malabry, France
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44
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Noubissi FK, Harkness T, Alexander CM, Ogle BM. Apoptosis-induced cancer cell fusion: a mechanism of breast cancer metastasis. FASEB J 2015; 29:4036-45. [PMID: 26085132 DOI: 10.1096/fj.15-271098] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 06/02/2015] [Indexed: 02/06/2023]
Abstract
Although cancer cell fusion has been suggested as a mechanism of cancer metastasis, the underlying mechanisms defining this process are poorly understood. In a recent study, apoptotic cells were newly identified as a type of cue that induces signaling via phosphatidylserine receptors to promote fusion of myoblasts. The microenvironment of breast tumors is often hypoxic, and because apoptosis is greatly increased in hypoxic conditions, we decided to investigate whether the mechanism of breast cancer cell fusion with mesenchymal stem/multipotent stromal cells (MSCs) involves apoptosis. We used a powerful tool for identification and tracking of hybrids based on bimolecular fluorescence complementation (BiFC) and found that breast cancer cells fused spontaneously with MSCs. This fusion was significantly enhanced with hypoxia and signaling associated with apoptotic cells, especially between nonmetastatic breast cancer cells and MSCs. In addition, the hybrids showed a significantly higher migratory capacity than did the parent cells. Taken together, these findings describe a mechanism by which hypoxia-induced apoptosis stimulates fusion between MSCs and breast tumor cells resulting in hybrids with an enhanced migratory capacity that may enable their dissemination to distant sites or metastases. In the long run, this study may provide new strategies for developing novel drugs for preventing cancer metastasis.
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Affiliation(s)
- Felicite K Noubissi
- *Department of Biomedical Engineering, Stem Cell Institute, Lillehei Heart Institute, Masonic Cancer Center, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA; and Department of Biomedical Engineering and Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Ty Harkness
- *Department of Biomedical Engineering, Stem Cell Institute, Lillehei Heart Institute, Masonic Cancer Center, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA; and Department of Biomedical Engineering and Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Caroline M Alexander
- *Department of Biomedical Engineering, Stem Cell Institute, Lillehei Heart Institute, Masonic Cancer Center, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA; and Department of Biomedical Engineering and Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Brenda M Ogle
- *Department of Biomedical Engineering, Stem Cell Institute, Lillehei Heart Institute, Masonic Cancer Center, University of Minnesota-Twin Cities, Minneapolis, Minnesota, USA; and Department of Biomedical Engineering and Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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45
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Zhou X, Merchak K, Lee W, Grande JP, Cascalho M, Platt JL. Cell Fusion Connects Oncogenesis with Tumor Evolution. THE AMERICAN JOURNAL OF PATHOLOGY 2015; 185:2049-60. [PMID: 26066710 DOI: 10.1016/j.ajpath.2015.03.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 02/08/2015] [Accepted: 03/02/2015] [Indexed: 12/30/2022]
Abstract
Cell fusion likely drives tumor evolution by undermining chromosomal and DNA stability and/or by generating phenotypic diversity; however, whether a cell fusion event can initiate malignancy and direct tumor evolution is unknown. We report that a fusion event involving normal, nontransformed, cytogenetically stable epithelial cells can initiate chromosomal instability, DNA damage, cell transformation, and malignancy. Clonal analysis of fused cells reveals that the karyotypic and phenotypic potential of tumors formed by cell fusion is established immediately or within a few cell divisions after the fusion event, without further ongoing genetic and phenotypic plasticity, and that subsequent evolution of such tumors reflects selection from the initial diverse population rather than ongoing plasticity of the progeny. Thus, one cell fusion event can both initiate malignancy and fuel evolution of the tumor that ensues.
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Affiliation(s)
- Xiaofeng Zhou
- Departments of Microbiology and Immunology and Surgery, University of Michigan, Ann Arbor, Michigan; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan
| | - Kevin Merchak
- Departments of Microbiology and Immunology and Surgery, University of Michigan, Ann Arbor, Michigan
| | - Woojin Lee
- Departments of Microbiology and Immunology and Surgery, University of Michigan, Ann Arbor, Michigan
| | - Joseph P Grande
- Division of Anatomic Pathology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota
| | - Marilia Cascalho
- Departments of Microbiology and Immunology and Surgery, University of Michigan, Ann Arbor, Michigan
| | - Jeffrey L Platt
- Departments of Microbiology and Immunology and Surgery, University of Michigan, Ann Arbor, Michigan.
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46
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ADAM12-directed ectodomain shedding of E-cadherin potentiates trophoblast fusion. Cell Death Differ 2015; 22:1970-84. [PMID: 25909890 DOI: 10.1038/cdd.2015.44] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 03/02/2015] [Accepted: 03/13/2015] [Indexed: 12/11/2022] Open
Abstract
Trophoblasts, placental cells of epithelial lineage, undergo extensive differentiation to form the cellular components of the placenta. Trophoblast progenitor cell differentiation into the multinucleated syncytiotrophoblast is a key developmental process required for placental function, where defects in syncytiotrophoblast formation and turnover associate with placental pathologies and link to poor pregnancy outcomes. The cellular and molecular processes governing syncytiotrophoblast formation are poorly understood, but require the activation of pathways that direct cell fusion. The protease, A Disintegrin and Metalloproteinase 12 (ADAM12), controls cell fusion in myoblasts and is highly expressed in the placenta localizing to multiple trophoblast populations. However, the importance of ADAM12 in regulating trophoblast fusion is unknown. Here, we describe a function for ADAM12 in regulating trophoblast fusion. Using two distinct trophoblast models of cell fusion, we show that ADAM12 is dynamically upregulated and is under the transcriptional control of protein kinase A. siRNA-directed loss of ADAM12 impedes spontaneous fusion of primary cytotrophoblasts, whereas overexpression of the secreted variant, ADAM12S, potentiates cell fusion in the Bewo trophoblast cell line. Mechanistically, both ectopic and endogenous levels of ADAM12 were shown to control trophoblast fusion through E-cadherin ectodomain shedding and remodeling of intercellular boundaries. This study describes a novel role for ADAM12 in placental development, specifically highlighting its importance in controlling the differentiation of villous cytotrophoblasts into multinucleated cellular structures. Moreover, this work identifies E-cadherin as a novel ADAM12 substrate, and highlights the significance that cell adhesion molecule ectodomain shedding has in normal development.
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Søe K, Hobolt-Pedersen AS, Delaisse JM. The elementary fusion modalities of osteoclasts. Bone 2015; 73:181-9. [PMID: 25527420 DOI: 10.1016/j.bone.2014.12.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/08/2014] [Accepted: 12/12/2014] [Indexed: 01/04/2023]
Abstract
The last step of the osteoclast differentiation process is cell fusion. Most efforts to understand the fusion mechanism have focused on the identification of molecules involved in the fusion process. Surprisingly, the basic fusion modalities, which are well known for fusion of other cell types, are not known for the osteoclast. Here we show that osteoclast fusion partners are characterized by differences in mobility, nuclearity, and differentiation level. Our demonstration was based on time-laps videos of human osteoclast preparations from three donors where 656 fusion events were analyzed. Fusions between a mobile and an immobile partner were most frequent (62%), while fusion between two mobile (26%) or two immobile partners (12%) was less frequent (p<0.001). In general, the immobile fusion partner contained more nuclei than the mobile one (p<0.01). Furthermore, enrichment in nuclei of an osteoclast with three or more nuclei resulted from fusion with a mono-nucleated cell in 67% of the cases (p<0.001), while mono-nucleated cells fused with a multinucleated cell in 61% of the cases (p<0.05). This observation suggested that a more mature osteoclast prefers to fuse with a less mature pre-osteoclast. This hypothesis was supported by a nucleus-tracing approach in a co-culture of more and less differentiated pre-osteoclasts/osteoclasts. Furthermore, we found that osteoclast fusion proceeds through primarily two different types of cell contacts: phagocytic-cup and broad-contact-surfaces (>80% of all fusions). We conclude that osteoclasts most often gain nuclei by addition of one nucleus at a time, and that this nucleus is most often delivered by a moving cell to an immobile cell. These characteristics fit the in vivo observations where mono-nucleated precursors migrating from the bone marrow fuse with more mature osteoclasts sitting on the bone surface. They also fit the fusion modalities of other cell types.
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Affiliation(s)
- Kent Søe
- Clinical Cell Biology, Vejle Hospital/Lillebaelt Hospital, Institute of Regional Health Research, University of Southern Denmark, Kabbeltoft 25, 7100 Vejle, Denmark.
| | - Anne-Sofie Hobolt-Pedersen
- Clinical Cell Biology, Vejle Hospital/Lillebaelt Hospital, Institute of Regional Health Research, University of Southern Denmark, Kabbeltoft 25, 7100 Vejle, Denmark.
| | - Jean-Marie Delaisse
- Clinical Cell Biology, Vejle Hospital/Lillebaelt Hospital, Institute of Regional Health Research, University of Southern Denmark, Kabbeltoft 25, 7100 Vejle, Denmark.
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Key T, Sarker M, de Antueno R, Rainey JK, Duncan R. The p10 FAST protein fusion peptide functions as a cystine noose to induce cholesterol-dependent liposome fusion without liposome tubulation. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1848:408-16. [PMID: 25450808 DOI: 10.1016/j.bbamem.2014.10.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 10/05/2014] [Accepted: 10/15/2014] [Indexed: 11/27/2022]
Abstract
The reovirus p10 fusion-associated small transmembrane (FAST) proteins are the smallest known membrane fusion proteins, and evolved specifically to mediate cell-cell, rather than virus-cell, membrane fusion. The 36-40-residue ectodomains of avian reovirus (ARV) and Nelson Bay reovirus (NBV) p10 contain an essential intramolecular disulfide bond required for both cell-cell fusion and lipid mixing between liposomes. To more clearly define the functional, biochemical and biophysical features of this novel fusion peptide, synthetic peptides representing the p10 ectodomains of ARV and NBV were analyzed by solution-state NMR spectroscopy, circular dichroism spectroscopy, fluorescence spectroscopy-based hydrophobicity analysis, and liposome binding and fusion assays. Results indicate that disulfide bond formation promotes exposure of hydrophobic residues, as indicated by bis-ANS binding and time-dependent peptide aggregation under aqueous conditions, implying the disulfide bond creates a small, geometrically constrained, cystine noose. Noose formation is required for peptide partitioning into liposome membranes and liposome lipid mixing, and electron microscopy revealed that liposome-liposome fusion occurs in the absence of liposome tubulation. In addition, p10 fusion peptide activity, but not membrane partitioning, is dependent on membrane cholesterol.
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Affiliation(s)
- Tim Key
- Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Muzaddid Sarker
- Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Roberto de Antueno
- Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jan K Rainey
- Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
| | - Roy Duncan
- Department of Microbiology & Immunology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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Gerbaud P, Pidoux G. Review: An overview of molecular events occurring in human trophoblast fusion. Placenta 2014; 36 Suppl 1:S35-42. [PMID: 25564303 DOI: 10.1016/j.placenta.2014.12.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 11/28/2014] [Accepted: 12/17/2014] [Indexed: 01/19/2023]
Abstract
During human placentation, mononuclear cytotrophoblasts fuse to form a multinucleated syncytia ensuring hormonal production and nutrient exchanges between the maternal and fetal circulation. Syncytia formation is essential for the maintenance of pregnancy and for fetal growth. The trophoblast cell fusion process first requires the acquisition of cell fusion properties, then cells set up plasma membrane protein macrocomplexes and fusogen machinery that trigger cell-cell fusion. Numerous proteins have been shown to be directly involved in the initiation of trophoblast cell fusion. These proteins must expressed at the right time and in the right place to trigger cell-cell fusion. In this review, we describe the role of certain fusogenic protein macrocomplexes that form the scaffold for the fusogen machinery underlying human trophoblastic-lipid mixing and merging of cell contents that lead to cell fusion in physiological conditions.
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Affiliation(s)
- P Gerbaud
- INSERM, U1139, Paris F-75006, France; Université Paris Descartes, Paris F-75006, France
| | - G Pidoux
- INSERM, U1139, Paris F-75006, France; Université Paris Descartes, Paris F-75006, France.
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Racca AC, Ridano ME, Camolotto S, Genti-Raimondi S, Panzetta-Dutari GM. A novel regulator of human villous trophoblast fusion: the Krüppel-like factor 6. ACTA ACUST UNITED AC 2014; 21:347-58. [DOI: 10.1093/molehr/gau113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 12/17/2014] [Indexed: 12/14/2022]
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