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Yu H, Zhang T, Lu H, Ma Q, Zhao D, Sun J, Wang Z. Granulocyte colony-stimulating factor (G-CSF) mediates bone resorption in periodontitis. BMC Oral Health 2021; 21:299. [PMID: 34118920 PMCID: PMC8196459 DOI: 10.1186/s12903-021-01658-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 05/30/2021] [Indexed: 01/13/2023] Open
Abstract
Background Granulocyte colony-stimulating factor (G-CSF) is an important immune factor that mediates bone metabolism by regulating the functions of osteoclasts and osteoblasts. Bone loss is a serious and progressive result of periodontitis. However, the mechanisms underlying the effects of G-CSF on periodontal inflammation have yet not been completely elucidated. Here, we examined whether an anti-G-CSF antibody could inhibit bone resorption in a model of experimental periodontitis and investigated the local expression of G-CSF in periodontal tissues. Methods Experimental periodontitis was induced in mice using ligatures. The levels of G-CSF in serum and bone marrow were measured; immunofluorescence was then performed to analyze the localization and expression of G-CSF in periodontal tissues. Mice with periodontitis were administered anti-G-CSF antibody by tail vein injection to assess the inhibition of bone resorption. Three-dimensional reconstruction was performed to measure bone destruction‐related parameters via micro-computed tomography analysis. Immunofluorescence staining was used to investigate the presence of osteocalcin-positive osteoblasts; tartrate-resistant acid phosphatase (TRAP) staining was used to observe osteoclast activity in alveolar bone. Results The level of G-CSF in serum was significantly elevated in mice with periodontitis. Immunofluorescence analyses showed that G-CSF was mostly expressed in the cell membrane of gingival epithelial cells; this expression was enhanced in the periodontitis group. Additionally, systemic administration of anti-G-CSF antibody significantly inhibited alveolar bone resorption, as evidenced by improvements in bone volume/total volume, bone surface area/bone volume, trabecular thickness, trabecular spacing, and trabecular pattern factor values. Immunofluorescence analysis revealed an enhanced number of osteocalcin-positive osteoblasts, while TRAP staining revealed reduction of osteoclast activity. Conclusions G-CSF expression levels were significantly up-regulated in the serum and gingival epithelial cells. Together, anti-G-CSF antibody administration could alleviates alveolar bone resorption, suggesting that G-CSF may be one of the essential immune factors that mediate the bone loss in periodontitis.
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Affiliation(s)
- Hui Yu
- Department of Stomatology, Beijing Chao-Yang Hospital, Capital Medical University, 8th Gongti South Road, Beijing, China.,Department of Stomatology, Affiliated Zhongshan Hospital of Dalian University, 6th Jiefang Street, Dalian, Liaoning, China
| | - Tianyi Zhang
- Shanxi Medical University, 382th WuyiRoad, Xinghualing Distrct, Taiyuan, Shanxi, China
| | - Haibin Lu
- Department of Stomatology, Affiliated Zhongshan Hospital of Dalian University, 6th Jiefang Street, Dalian, Liaoning, China
| | - Qi Ma
- Department of Pathology, Affiliated Zhongshan Hospital of Dalian University, 6th Jiefang Street, Dalian, Liaoning, China
| | - Dong Zhao
- Department of Stomatology, Beijing Chao-Yang Hospital, Capital Medical University, 8th Gongti South Road, Beijing, China
| | - Jiang Sun
- Department of Periodontology, Dalian Stomatological Hospital, 935th Changjiang Road, Dalian, Liaoning, China.
| | - Zuomin Wang
- Department of Stomatology, Beijing Chao-Yang Hospital, Capital Medical University, 8th Gongti South Road, Beijing, China.
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2
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Polavaram NS, Dutta S, Islam R, Bag AK, Roy S, Poitz D, Karnes J, Hofbauer LC, Kohli M, Costello BA, Jimenez R, Batra SK, Teply BA, Muders MH, Datta K. Tumor- and osteoclast-derived NRP2 in prostate cancer bone metastases. Bone Res 2021; 9:24. [PMID: 33990538 PMCID: PMC8121836 DOI: 10.1038/s41413-021-00136-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 10/22/2020] [Accepted: 11/26/2020] [Indexed: 01/13/2023] Open
Abstract
Understanding the role of neuropilin 2 (NRP2) in prostate cancer cells as well as in the bone microenvironment is pivotal in the development of an effective targeted therapy for the treatment of prostate cancer bone metastasis. We observed a significant upregulation of NRP2 in prostate cancer cells metastasized to bone. Here, we report that targeting NRP2 in cancer cells can enhance taxane-based chemotherapy with a better therapeutic outcome in bone metastasis, implicating NRP2 as a promising therapeutic target. Since, osteoclasts present in the tumor microenvironment express NRP2, we have investigated the potential effect of targeting NRP2 in osteoclasts. Our results revealed NRP2 negatively regulates osteoclast differentiation and function in the presence of prostate cancer cells that promotes mixed bone lesions. Our study further delineated the molecular mechanisms by which NRP2 regulates osteoclast function. Interestingly, depletion of NRP2 in osteoclasts in vivo showed a decrease in the overall prostate tumor burden in the bone. These results therefore indicate that targeting NRP2 in prostate cancer cells as well as in the osteoclastic compartment can be beneficial in the treatment of prostate cancer bone metastasis.
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Affiliation(s)
- Navatha Shree Polavaram
- Department of Microbiology and Pathology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Samikshan Dutta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Ridwan Islam
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Arup K Bag
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sohini Roy
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - David Poitz
- Institute for Clinical Chemistry, University Hospital Dresden, Dresden, Germany
| | | | - Lorenz C Hofbauer
- Center for Healthy Aging and Bone Lab Dresden, Department of Medicine III, Technische Universität Dresden, Dresden, Germany
| | - Manish Kohli
- School of Medicine, Division of Oncology, Huntsman Cancer Institute, Salt Lake City, UT, USA
| | | | - Raffael Jimenez
- Division of Anatomic Pathology, Department of Pathology and Laboratory Medicine, Mayo Clinic, Rochester, MN, USA
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Benjamin A Teply
- Internal Medicine, Division of Oncology & Hematology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Michael H Muders
- Rudolf- Becker Laboratory for Prostate Cancer Research, Institute of Pathology, University of Bonn Medical Center, Bonn, Germany.
| | - Kaustubh Datta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA.
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3
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Rafieemehr H, Maleki Behzad M, Azandeh S, Farshchi N, Ghasemi Dehcheshmeh M, Saki N. Chemo/radiotherapy-Induced Bone Marrow Niche Alterations. Cancer Invest 2020; 39:180-194. [PMID: 33225760 DOI: 10.1080/07357907.2020.1855353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Bone marrow (BM) niche is a specific microenvironment for hematopoietic stem cells (HSCs) as well as non-hematopoietic cells. Evidence shows that chemo/radiotherapy can lead to the disruption of different properties of HSCs such as proliferation, differentiation, localization, self-renewa, and steady-state of cell populations. Investigations have shown that the deregulation of balance within the marrow cavity due to chemo/radiotherapy could lead to bone loss, abnormal hematopoiesis, and enhanced differentiation potential of mesenchymal stem cells towards the adipogenic lineage. Therefore, understanding the underlying mechanisms of chemo/radiotherapy induced BM niche changes may lead to the application of appropriate therapeutic agents to prevent BM niche defects. Highlights Chemo/radiotherapy disrupts the steady-state of bone marrow niche cells and result in deregulation of normal balance of stromal cell populations. Chemo/radiotherapy agents play a significant role in reducing of bone formation as well as fat accumulation in the bone marrow niche. Targeting molecular pathways may lead to recovery of bone marrow niches after chemo/radiotherapy.
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Affiliation(s)
- Hassan Rafieemehr
- Department of Medical Laboratory Sciences, School of Paramedicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Masumeh Maleki Behzad
- Thalassemia & Hemoglobinopathy Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.,Blood Transfusion Research Center, High Institute for Research and Education in Transfusion, Hamadan, Iran
| | - Saeed Azandeh
- Cellular and Molecular Research Center (CMRC), Department of Anatomical Sciences, Faculty of Medicin, Ahvaz Jundishapur University of Medical Sciences (AJUMS), Ahvaz, Iran
| | - Niloofar Farshchi
- Thalassemia & Hemoglobinopathy Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | | | - Najmaldin Saki
- Thalassemia & Hemoglobinopathy Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
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4
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Guder C, Gravius S, Burger C, Wirtz DC, Schildberg FA. Osteoimmunology: A Current Update of the Interplay Between Bone and the Immune System. Front Immunol 2020; 11:58. [PMID: 32082321 PMCID: PMC7004969 DOI: 10.3389/fimmu.2020.00058] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 01/09/2020] [Indexed: 12/11/2022] Open
Abstract
Immunology, already a discipline in its own right, has become a major part of many different medical fields. However, its relationship to orthopedics and trauma surgery has unfortunately, and perhaps unjustly, been developing rather slowly. Discoveries in recent years have emphasized the immense breadth of communication and connection between both systems and, importantly, the highly promising therapeutic opportunities. Recent discoveries of factors originally assigned to the immune system have now also been shown to have a significant impact on bone health and disease, which has greatly changed how we approach treatment of bone pathologies. In case of bone fracture, immune cells, especially macrophages, are present throughout the whole healing process, assure defense against pathogens and discharge a complex variety of effectors to regulate bone modeling. In rheumatoid arthritis and osteoporosis, the immune system contributes to the formation of the pathological and chronic conditions. Fascinatingly, prosthesis failure is not at all solely a mechanical problem of improper strain but works in conjunction with an active contribution of the immune system as a reaction to irritant debris from material wear. Unraveling conjoined mechanisms of the immune and osseous systems heralds therapeutic possibilities for ailments of both. Contemplation of the bone as merely an unchanging support pillar is outdated and obsolete. Instead it is mandatory that this highly diverse network be incorporated in our understanding of the immune system and hematopoiesis.
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Affiliation(s)
- Christian Guder
- Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Bonn, Germany
| | - Sascha Gravius
- Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Bonn, Germany.,Department of Orthopedics and Trauma Surgery, University Medical Center Mannheim of University Heidelberg, Mannheim, Germany
| | - Christof Burger
- Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Bonn, Germany
| | - Dieter C Wirtz
- Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Bonn, Germany
| | - Frank A Schildberg
- Clinic for Orthopedics and Trauma Surgery, University Hospital Bonn, Bonn, Germany
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5
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Osteoimmunology: evolving concepts in bone-immune interactions in health and disease. Nat Rev Immunol 2019; 19:626-642. [PMID: 31186549 DOI: 10.1038/s41577-019-0178-8] [Citation(s) in RCA: 346] [Impact Index Per Article: 69.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/13/2019] [Indexed: 12/14/2022]
Abstract
In terrestrial vertebrates, bone tissue constitutes the 'osteoimmune' system, which functions as a locomotor organ and a mineral reservoir as well as a primary lymphoid organ where haematopoietic stem cells are maintained. Bone and mineral metabolism is maintained by the balanced action of bone cells such as osteoclasts, osteoblasts and osteocytes, yet subverted by aberrant and/or prolonged immune responses under pathological conditions. However, osteoimmune interactions are not restricted to the unidirectional effect of the immune system on bone metabolism. In recent years, we have witnessed the discovery of effects of bone cells on immune regulation, including the function of osteoprogenitor cells in haematopoietic stem cell regulation and osteoblast-mediated suppression of haematopoietic malignancies. Moreover, the dynamic reciprocal interactions between bone and malignancies in remote organs have attracted attention, extending the horizon of osteoimmunology. Here, we discuss emerging concepts in the osteoimmune dialogue in health and disease.
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6
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de Kruijf EJFM, Fibbe WE, van Pel M. Cytokine-induced hematopoietic stem and progenitor cell mobilization: unraveling interactions between stem cells and their niche. Ann N Y Acad Sci 2019; 1466:24-38. [PMID: 31006885 PMCID: PMC7217176 DOI: 10.1111/nyas.14059] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/15/2019] [Accepted: 02/28/2019] [Indexed: 02/06/2023]
Abstract
Peripheral blood hematopoietic stem and progenitor cells (HSPCs), mobilized by granulocyte colony‐stimulating factor, are widely used as a source for both autologous and allogeneic stem cell transplantation. The use of mobilized HSPCs has several advantages over traditional bone marrow–derived HSPCs, including a less invasive harvesting process for the donor, higher HSPC yields, and faster hematopoietic reconstitution in the recipient. For years, the mechanisms by which cytokines and other agents mobilize HSPCs from the bone marrow were not fully understood. The field of stem cell mobilization research has advanced significantly over the past decade, with major breakthroughs in the elucidation of the complex mechanisms that underlie stem cell mobilization. In this review, we provide an overview of the events that underlie HSPC mobilization and address the relevant cellular and molecular components of the bone marrow niche. Furthermore, current and future mobilizing agents will be discussed.
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Affiliation(s)
- Evert-Jan F M de Kruijf
- Section of Stem Cell Biology, Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Willem E Fibbe
- Section of Stem Cell Biology, Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
| | - Melissa van Pel
- Section of Stem Cell Biology, Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands
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7
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Hoggatt J, Kfoury Y, Scadden DT. Hematopoietic Stem Cell Niche in Health and Disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2017; 11:555-81. [PMID: 27193455 DOI: 10.1146/annurev-pathol-012615-044414] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Regulation of stem cells in adult tissues is a key determinant of how well an organism can respond to the stresses of physiological challenge and disease. This is particularly true of the hematopoietic system, where demands on host defenses can call for an acute increase in cell production. Hematopoietic stem cells receive the regulatory signals for cell production in adult mammals in the bone marrow, a tissue with higher-order architectural and functional organization than previously appreciated. Here, we review the data defining particular structural components and heterologous cells in the bone marrow that participate in hematopoietic stem cell function. Further, we explore the case for stromal-hematopoietic cell interactions contributing to neoplastic myeloid disease. As the hematopoietic regulatory networks in the bone marrow are revealed, it is anticipated that strategies will emerge for how to enhance or inhibit production of specific blood cells. In that way, the control of hematopoiesis will enter the domain of therapies to modulate broad aspects of hematopoiesis, both normal and malignant.
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Affiliation(s)
- Jonathan Hoggatt
- Harvard Stem Cell Institute, Cambridge, Massachusetts 02138.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138.,Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114;
| | - Youmna Kfoury
- Harvard Stem Cell Institute, Cambridge, Massachusetts 02138.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138.,Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114;
| | - David T Scadden
- Harvard Stem Cell Institute, Cambridge, Massachusetts 02138.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138.,Center for Regenerative Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114;
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8
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Jung WC, Levesque JP, Ruitenberg MJ. It takes nerve to fight back: The significance of neural innervation of the bone marrow and spleen for immune function. Semin Cell Dev Biol 2017; 61:60-70. [DOI: 10.1016/j.semcdb.2016.08.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Revised: 08/09/2016] [Accepted: 08/11/2016] [Indexed: 01/17/2023]
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9
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Cellular players of hematopoietic stem cell mobilization in the bone marrow niche. Int J Hematol 2016; 105:129-140. [PMID: 27943116 DOI: 10.1007/s12185-016-2162-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 11/21/2016] [Accepted: 11/29/2016] [Indexed: 12/23/2022]
Abstract
Hematopoietic stem cells (HSC) reside in perivascular regions of the bone marrow (BM) embedded within a complex regulatory unit called the niche. Cellular components of HSC niches include vascular endothelial cells, mesenchymal stromal progenitor cells and a variety of mature hematopoietic cells such as macrophages, neutrophils, and megakaryocytes-further regulated by sympathetic nerves and complement components as described in this review. Three decades ago the discovery that cytokines induce a large number of HSC to mobilize from the BM into the blood where they are easily harvested, revolutionised the field of HSC transplantation-curative for immune-deficiencies and some malignancies. However, despite now routine use of granulocyte-colony stimulating factor (G-CSF) to mobilise HSC for transplant, only in last 15 years has research on the mechanisms behind why and how HSC can be induced to move into the blood began. These studies have revealed the complexity of the niche that retains HSC in the BM. This review describes how BM niches and HSC themselves change during administration of G-CSF-or in the recovery phase of chemotherapy-to facilitate movement of HSC into the blood, and research now leading to development of novel therapeutics to further boost HSC mobilization and transplant success.
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10
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Loi F, Córdova LA, Pajarinen J, Lin TH, Yao Z, Goodman SB. Inflammation, fracture and bone repair. Bone 2016; 86:119-30. [PMID: 26946132 PMCID: PMC4833637 DOI: 10.1016/j.bone.2016.02.020] [Citation(s) in RCA: 689] [Impact Index Per Article: 86.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/30/2015] [Accepted: 02/29/2016] [Indexed: 12/20/2022]
Abstract
The reconstitution of lost bone is a subject that is germane to many orthopedic conditions including fractures and non-unions, infection, inflammatory arthritis, osteoporosis, osteonecrosis, metabolic bone disease, tumors, and periprosthetic particle-associated osteolysis. In this regard, the processes of acute and chronic inflammation play an integral role. Acute inflammation is initiated by endogenous or exogenous adverse stimuli, and can become chronic in nature if not resolved by normal homeostatic mechanisms. Dysregulated inflammation leads to increased bone resorption and suppressed bone formation. Crosstalk among inflammatory cells (polymorphonuclear leukocytes and cells of the monocyte-macrophage-osteoclast lineage) and cells related to bone healing (cells of the mesenchymal stem cell-osteoblast lineage and vascular lineage) is essential to the formation, repair and remodeling of bone. In this review, the authors provide a comprehensive summary of the literature related to inflammation and bone repair. Special emphasis is placed on the underlying cellular and molecular mechanisms, and potential interventions that can favorably modulate the outcome of clinical conditions that involve bone repair.
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Affiliation(s)
- Florence Loi
- 300 Pasteur Drive, Edwards Building, Room R116, Department of Orthopaedic Surgery, Stanford University, Stanford, CA 94305, USA.
| | - Luis A Córdova
- 300 Pasteur Drive, Edwards Building, Room R116, Department of Orthopaedic Surgery, Stanford University, Stanford, CA 94305, USA; Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Chile, Sergio Livingstone Polhammer 943, Independencia, 8380000 Santiago, Chile.
| | - Jukka Pajarinen
- 300 Pasteur Drive, Edwards Building, Room R116, Department of Orthopaedic Surgery, Stanford University, Stanford, CA 94305, USA.
| | - Tzu-hua Lin
- 300 Pasteur Drive, Edwards Building, Room R116, Department of Orthopaedic Surgery, Stanford University, Stanford, CA 94305, USA.
| | - Zhenyu Yao
- 300 Pasteur Drive, Edwards Building, Room R116, Department of Orthopaedic Surgery, Stanford University, Stanford, CA 94305, USA.
| | - Stuart B Goodman
- 300 Pasteur Drive, Edwards Building, Room R116, Department of Orthopaedic Surgery, Stanford University, Stanford, CA 94305, USA; 300 Pasteur Drive, Edwards Building, Room R114, Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
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11
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The Hematopoietic Niche in Myeloproliferative Neoplasms. Mediators Inflamm 2015; 2015:347270. [PMID: 26696752 PMCID: PMC4677214 DOI: 10.1155/2015/347270] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/12/2015] [Indexed: 12/18/2022] Open
Abstract
Specialized microanatomical areas of the bone marrow provide the signals that are mandatory for the maintenance and regulation of hematopoietic stem cells (HSCs) and progenitor cells. A complex microenvironment adjacent to the marrow vasculature (vascular niche) and close to the endosteum (endosteal niche) harbors multiple cell types including mesenchymal stromal cells and their derivatives such as CAR cells expressing high levels of chemokines C-X-C motif ligand 12 and early osteoblastic lineage cells, endothelial cells, and megakaryocytes. The characterization of the cellular and molecular networks operating in the HSC niche has opened new perspectives for the understanding of the bidirectional cross-talk between HSCs and stromal cell populations in normal and malignant conditions. A structural and functional remodeling of the niche may contribute to the development of myeloproliferative neoplasms (MPN). Malignant HSCs may alter the function and survival of MSCs that do not belong to the neoplastic clone. For example, a regression of nestin+ MSCs by apoptosis has been attributed to neuroglial damage in MPN. Nonneoplastic MSCs in turn can promote aggressiveness and drug resistance of malignant cells. In the future, strategies to counteract the pathological interaction between the niche and neoplastic HSCs may offer additional treatment strategies for MPN patients.
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12
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Evidence that a lipolytic enzyme--hematopoietic-specific phospholipase C-β2--promotes mobilization of hematopoietic stem cells by decreasing their lipid raft-mediated bone marrow retention and increasing the promobilizing effects of granulocytes. Leukemia 2015; 30:919-28. [PMID: 26582648 PMCID: PMC4823158 DOI: 10.1038/leu.2015.315] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 10/14/2015] [Accepted: 10/26/2015] [Indexed: 12/26/2022]
Abstract
Hematopoietic stem/progenitor cells (HSPCs) reside in the bone marrow (BM) microenvironment and are retained there by the interaction of membrane lipid raft-associated receptors, such as the α-chemokine receptor CXCR4 and the α4β1-integrin (VLA-4, very late antigen 4 receptor) receptor, with their respective specific ligands, stromal-derived factor 1 and vascular cell adhesion molecule 1, expressed in BM stem cell niches. The integrity of the lipid rafts containing these receptors is maintained by the glycolipid glycosylphosphatidylinositol anchor (GPI-A). It has been reported that a cleavage fragment of the fifth component of the activated complement cascade, C5a, has an important role in mobilizing HSPCs into the peripheral blood (PB) by (i) inducing degranulation of BM-residing granulocytes and (ii) promoting their egress from the BM into the PB so that they permeabilize the endothelial barrier for subsequent egress of HSPCs. We report here that hematopoietic cell-specific phospholipase C-β2 (PLC-β2) has a crucial role in pharmacological mobilization of HSPCs. On the one hand, when released during degranulation of granulocytes, it digests GPI-A, thereby disrupting membrane lipid rafts and impairing retention of HSPCs in BM niches. On the other hand, it is an intracellular enzyme required for degranulation of granulocytes and their egress from BM. In support of this dual role, we demonstrate that PLC-β2-knockout mice are poor mobilizers and provide, for the first time, evidence for the involvement of this lipolytic enzyme in the mobilization of HSPCs.
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