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Karnik SJ, Nazzal MK, Kacena MA, Bruzzaniti A. Megakaryocyte Secreted Factors Regulate Bone Marrow Niche Cells During Skeletal Homeostasis, Aging, and Disease. Calcif Tissue Int 2023; 113:83-95. [PMID: 37243755 PMCID: PMC11179715 DOI: 10.1007/s00223-023-01095-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/01/2023] [Indexed: 05/29/2023]
Abstract
The bone marrow microenvironment contains a diverse array of cell types under extensive regulatory control and provides for a novel and complex mechanism for bone regulation. Megakaryocytes (MKs) are one such cell type that potentially acts as a master regulator of the bone marrow microenvironment due to its effects on hematopoiesis, osteoblastogenesis, and osteoclastogenesis. While several of these processes are induced/inhibited through MK secreted factors, others are primarily regulated by direct cell-cell contact. Notably, the regulatory effects that MKs exert on these different cell populations has been found to change with aging and disease states. Overall, MKs are a critical component of the bone marrow that should be considered when examining regulation of the skeletal microenvironment. An increased understanding of the role of MKs in these physiological processes may provide insight into novel therapies that can be used to target specific pathways important in hematopoietic and skeletal disorders.
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Affiliation(s)
- Sonali J Karnik
- Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Murad K Nazzal
- Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Melissa A Kacena
- Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, USA.
- Richard L. Roudebush VA Medical Center, Indianapolis, IN, USA.
| | - Angela Bruzzaniti
- Department of Biomedical Sciences and Comprehensive Care, Indiana University School of Dentistry, Indianapolis, IN, USA.
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Liu X, Tao J, Yao Y, Yang P, Wang J, Yu M, Hou J, Zhang Y, Gui L. Resveratrol induces proliferation in preosteoblast cell MC3T3-E1 via GATA-1 activating autophagy. Acta Biochim Biophys Sin (Shanghai) 2021; 53:1495-1504. [PMID: 34637502 DOI: 10.1093/abbs/gmab135] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Indexed: 01/08/2023] Open
Abstract
Resveratrol (RSV) could promote osteogenic activity, but its clinical application has been hampered in view of its poor bioavailability. Therefore, it is desirable to identify with certainty the molecular target of its bone mass boosting function, which is crucial to the design of an effective therapeutic strategy for the optimal treatment of osteoporosis. Emerging evidence has indicated that GATA-1, an important transcription factor in megakaryocyte and erythrocyte differentiation, can directly activate autophagy in erythrocytes, alluding to its impact on bone metabolism. In light of this, we sought to determine whether GATA-1 would be a putative target by which RSV would act on osteoblast proliferation and, if so, to explore the underlying mechanism involved in the process. We examined the cell viability, colony formation, cell cyclin expression, autophagy level, and the expression levels of GATA-1 and adenosine 5'-monophosphate (AMP)-activated protein kinase α (AMPKα) in osteoblastic cell strain MC3T3-E1. The results showed that RSV promoted the proliferation process in MC3T3-E1 coupled with increased expression of GATA-1 and phosphorylated AMPKα and activated autophagy. When GATA-1 was interfered with siRNA, both autophagy and proliferation were decreased. Administration of the agonist of phosphorylated AMPKα1 (Thr172) promoted the translocation of GATA-1 into the nucleus. Based on the above results, we concluded that RSV induces the proliferation of MC3T3-E1 by increasing GATA-1 expression, which thence activates autophagy; and of note, AMPKα is one of the upstream regulators of GATA-1.
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Affiliation(s)
- Xiang Liu
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming 650500, China
| | - Jun Tao
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming 650500, China
| | - Yueyi Yao
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming 650500, China
| | - Ping Yang
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming 650500, China
| | - Juhui Wang
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming 650500, China
| | - Mali Yu
- Science and Technology Achievement Incubation Center, Kunming Medical University, Kunming 650500, China
| | - Jianhong Hou
- Department of Orthopaedics, The Third People’s Hospital of Yunnan Province, Kunming 650101, China
| | - Ying Zhang
- Faculty of Nursing, Kunming Medical University, Kunming 650500, China
| | - Li Gui
- Department of Endocrinology, The Third People’s Hospital of Yunnan Province, Kunming 650101, China
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Lee SH, Ihn HJ, Park EK, Kim JE. S100 Calcium-Binding Protein P Secreted from Megakaryocytes Promotes Osteoclast Maturation. Int J Mol Sci 2021; 22:ijms22116129. [PMID: 34200172 PMCID: PMC8201154 DOI: 10.3390/ijms22116129] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 12/26/2022] Open
Abstract
Megakaryocytes (MKs) differentiate from hematopoietic stem cells and produce platelets at the final stage of differentiation. MKs directly interact with bone cells during bone remodeling. However, whether MKs are involved in regulating bone metabolism through indirect regulatory effects on bone cells is unclear. Here, we observed increased osteoclast differentiation of bone marrow-derived macrophages (BMMs) cultured in MK-cultured conditioned medium (MK CM), suggesting that this medium contains factors secreted from MKs that affect osteoclastogenesis. To identify the MK-secreted factor, DNA microarray analysis of the human leukemia cell line K562 and MKs was performed, and S100 calcium-binding protein P (S100P) was selected as a candidate gene affecting osteoclast differentiation. S100P was more highly expressed in MKs than in K562 cells, and showed higher levels in MK CM than in K562-cultured conditioned medium. In BMMs cultured in the presence of recombinant human S100P protein, osteoclast differentiation was promoted and marker gene expression was increased. The resorption area was significantly larger in S100P protein-treated osteoclasts, demonstrating enhanced resorption activity. Overall, S100P secreted from MKs promotes osteoclast differentiation and resorption activity, suggesting that MKs indirectly regulate osteoclast differentiation and activity through the paracrine action of S100P.
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Affiliation(s)
- Seung-Hoon Lee
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Korea;
- BK21 Four KNU Convergence Educational Program of Biomedical Sciences for Creative Future Talents, Department of Biomedical Science, Kyungpook National University, Daegu 41944, Korea
- Cell and Matrix Research Institute, Kyungpook National University, Daegu 41944, Korea;
| | - Hye Jung Ihn
- Cell and Matrix Research Institute, Kyungpook National University, Daegu 41944, Korea;
| | - Eui Kyun Park
- Department of Oral Pathology and Regenerative Medicine, School of Dentistry, IHBR, Kyungpook National University, Daegu 41944, Korea;
| | - Jung-Eun Kim
- Department of Molecular Medicine, School of Medicine, Kyungpook National University, Daegu 41944, Korea;
- BK21 Four KNU Convergence Educational Program of Biomedical Sciences for Creative Future Talents, Department of Biomedical Science, Kyungpook National University, Daegu 41944, Korea
- Cell and Matrix Research Institute, Kyungpook National University, Daegu 41944, Korea;
- Correspondence: ; Tel.: +82-53-420-4949
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Yang J, Zhao S, Ma D. Biological Characteristics and Regulation of Early Megakaryocytopoiesis. Stem Cell Rev Rep 2020; 15:652-663. [PMID: 31230184 DOI: 10.1007/s12015-019-09905-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
For decades, megakaryocytopoiesis is believed to occur following a classical binary hierarchical developmental model. This model is based on an analysis of predefined flow-sorted cell populations by using cell surface markers. However, this classical model has been challenged by increasing evidences obtained with new techniques which integrating flow cytometric, transcriptomic and functional data at single-cell level and with lineage tracing technique. These recent advances in megakaryocytopoiesis proposed that commitment of haematopoietic stem cells (HSCs) towards megakaryocytic lineage occurs in much earlier stage than that postulated in the classical model. There may exist multipotent but megakaryocyte (MK)/platelet-biased HSCs within HSC compartment and even HSCs can directly differentiate into MKs in steady state or in response to stress. In this review, we focus on recent findings about differentiation from commitment of HSCs to MK and its regulation, and discuss future directions in this research field.
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Affiliation(s)
- Jingang Yang
- Department of Experimental Medicine, General Hospital of Northern Theatre Command, 83 Wenhua Road, Shenhe District, Shenyang, Liaoning, People's Republic of China
| | - Song Zhao
- Department of Experimental Medicine, General Hospital of Northern Theatre Command, 83 Wenhua Road, Shenhe District, Shenyang, Liaoning, People's Republic of China
| | - Dongchu Ma
- Department of Experimental Medicine, General Hospital of Northern Theatre Command, 83 Wenhua Road, Shenhe District, Shenyang, Liaoning, People's Republic of China.
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Curtis KJ, Oberman AG, Niebur GL. Effects of mechanobiological signaling in bone marrow on skeletal health. Ann N Y Acad Sci 2019; 1460:11-24. [PMID: 31508828 DOI: 10.1111/nyas.14232] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/09/2019] [Accepted: 08/15/2019] [Indexed: 01/27/2023]
Abstract
Bone marrow is a cellular tissue that forms within the pore space and hollow diaphysis of bones. As a tissue, its primary function is to support the hematopoietic progenitor cells that maintain the populations of both erythroid and myeloid lineage cells in the bone marrow, making it an essential element of normal mammalian physiology. However, bone's primary function is load bearing, and deformations induced by external forces are transmitted to the encapsulated marrow. Understanding the effects of these mechanical inputs on marrow function and adaptation requires knowledge of the material behavior of the marrow at multiple scales, the loads that are applied, and the mechanobiology of the cells. This paper reviews the current state of knowledge of each of these factors. Characterization of the marrow mechanical environment and its role in skeletal health and other marrow functions remains incomplete, but research on the topic is increasing, driven by interest in skeletal adaptation and the mechanobiology of cancer metastasis.
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Affiliation(s)
- Kimberly J Curtis
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana.,Advanced Diagnostics and Therapeutics Initiative, University of Notre Dame, Notre Dame, Indiana
| | - Alyssa G Oberman
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana
| | - Glen L Niebur
- Tissue Mechanics Laboratory, Bioengineering Graduate Program, University of Notre Dame, Notre Dame, Indiana.,Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana.,Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana
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Ferguson J, Atit RP. A tale of two cities: The genetic mechanisms governing calvarial bone development. Genesis 2019; 57:e23248. [PMID: 30155972 PMCID: PMC7433025 DOI: 10.1002/dvg.23248] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 08/21/2018] [Accepted: 08/23/2018] [Indexed: 12/25/2022]
Abstract
The skull bones must grow in a coordinated, three-dimensional manner to coalesce and form the head and face. Mammalian skull bones have a dual embryonic origin from cranial neural crest cells (CNCC) and paraxial mesoderm (PM) and ossify through intramembranous ossification. The calvarial bones, the bones of the cranium which cover the brain, are derived from the supraorbital arch (SOA) region mesenchyme. The SOA is the site of frontal and parietal bone morphogenesis and primary center of ossification. The objective of this review is to frame our current in vivo understanding of the morphogenesis of the calvarial bones and the gene networks regulating calvarial bone initiation in the SOA mesenchyme.
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Affiliation(s)
- James Ferguson
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106
- Department of Genetics, Case Western Reserve University, Cleveland OH 44106
- Department of Dermatology, Case Western Reserve University, Cleveland OH 44106
| | - Radhika P. Atit
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106
- Department of Genetics, Case Western Reserve University, Cleveland OH 44106
- Department of Dermatology, Case Western Reserve University, Cleveland OH 44106
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Higher Platelet-to-Lymphocyte Ratio Increased the Risk of Sarcopenia in the Community-Dwelling Older Adults. Sci Rep 2017; 7:16609. [PMID: 29192175 PMCID: PMC5709494 DOI: 10.1038/s41598-017-16924-y] [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: 07/05/2017] [Accepted: 11/20/2017] [Indexed: 12/18/2022] Open
Abstract
The platelet-to-lymphocyte ratio (PLR) has been extensively studied in oncologic diseases. However, the correlation between PLR and sarcopenia remains unknown. In this cross-sectional analysis, we enrolled 3,671 non-institutionalized individuals from the National Health and Nutrition Examination Survey (NHANES) III (1988–1994) aged ≥60 years and whose complete blood counts (CBCs), body composition measurements, and related demographic information was available. Skeletal muscle mass was assessed using a previously published equation (including age, sex, height, and bioelectrical impedance analysis). PLR values were estimated based on laboratory data. Multiple linear and logistic regression analyses, quartile-based stratified odds ratio comparisons, and trend tests were performed. Elevations in serum PLR values were significantly associated with sarcopenia status and negatively associated with skeletal muscle index. After additionally adjusting for other covariates, the significant negative correlation remained; moreover, participants with highest serum PLR values (≥155) had 2.36 times greater risk of sarcopenia than those with lowest PLR values (<90; odds ratio (OR) = 2.36; 95% confidence interval (CI): 1.21–3.31; p < 0.01). Higher PLR levels are associated with a greater risk of sarcopenia in geriatric populations. Thus, PLR as an inexpensive and easily measurable parameter can be considered as an inflammatory biomarker for sarcopenia.
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Effect of cadmium on bone tissue in growing animals. ACTA ACUST UNITED AC 2016; 68:391-7. [PMID: 27312893 DOI: 10.1016/j.etp.2016.06.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 05/20/2016] [Accepted: 06/01/2016] [Indexed: 11/22/2022]
Abstract
Accumulation of cadmium (Cd), an extremely toxic metal, can cause renal failure, decreased vitamin D synthesis, and consequently osteoporosis. The aim of this work was to evaluate the effect of Cd on two types of bone in growing Wistar rats. Sixteen 21-day-old male Wistar rats were assigned to one of two groups. The Cd group subcutaneously received 0.5mg/kg of CdCl2 5 times weekly for 3 months. The control group similarly received bidistilled water. Following euthanasia, the mandibles and tibiae were resected, fixed, decalcified and processed histologically to obtain sections for H&E and tartrate-resistant acid phosphatase (TRAP) staining. Photomicrographs were used to determine bone volume (BV/TV%), total growth cartilage width (GPC.Wi) hypertrophic cartilage width (HpZ.Wi), percentage of yellow bone marrow (%YBM), megakaryocyte number (N.Mks/mm(2)), and TRAP+osteoclast number (N.TRAP+Ocl/mm(2)). Results were statistically analyzed using Student's t test. Cd exposed animals showed a significant decrease in subchondral bone volume and a significant increase in TRAP+ osteoclast number and percentage of yellow bone marrow in the tibia, and an increase in megakaryocyte number in mandibular interradicular bone. No significant differences were observed in the remaining parameters. The results obtained with this experimental design show that Cd would seemingly have a different effect on subchondral and interradicular bone. The decrease in bone volume and increase in tibial yellow bone marrow suggest that cadmium inhibits differentiation of mesenchymal cells to osteoblasts, favoring differentiation into adipocytes. The different effects of Cd on interradicular bone might be due to the protective effect of the mastication forces.
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Haider MT, Hunter KD, Robinson SP, Graham TJ, Corey E, Dear TN, Hughes R, Brown NJ, Holen I. Rapid modification of the bone microenvironment following short-term treatment with Cabozantinib in vivo. Bone 2015; 81:581-592. [PMID: 26279137 PMCID: PMC4768060 DOI: 10.1016/j.bone.2015.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/18/2015] [Accepted: 08/04/2015] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Bone metastasis remains incurable with treatment restricted to palliative care. Cabozantinib (CBZ) is targeted against multiple receptor tyrosine kinases involved in tumour pathobiology, including hepatocyte growth factor receptor (MET) and vascular endothelial growth factor receptor 2 (VEGFR-2). CBZ has demonstrated clinical activity in advanced prostate cancer with resolution of lesions visible on bone scans, implicating a potential role of the bone microenvironment as a mediator of CBZ effects. We characterised the effects of short-term administration of CBZ on bone in a range of in vivo models to determine how CBZ affects bone in the absence of tumour. METHODS Studies were performed in a variety of in vivo models including male and female BALB/c nude mice (age 6-17-weeks). Animals received CBZ (30 mg/kg, 5× weekly) or sterile H2O control for 5 or 10 days. Effects on bone integrity (μCT), bone cell activity (PINP, TRAP ELISA), osteoblast and osteoclast number/mm trabecular bone surface, area of epiphyseal growth plate cartilage, megakaryocyte numbers and bone marrow composition were assessed. Effects of longer-term treatment (15-day & 6-week administration) were assessed in male NOD/SCID and beige SCID mice. RESULTS CBZ treatment had significant effects on the bone microenvironment, including reduced osteoclast and increased osteoblast numbers compared to control. Trabecular bone structure was altered after 8 administrations. A significant elongation of the epiphyseal growth plate, in particular the hypertrophic chondrocyte zone, was observed in all CBZ treated animals irrespective of administration schedule. Both male and female BALB/c nude mice had increased megakaryocyte numbers/mm(2) tissue after 10-day CBZ treatment, in addition to vascular ectasia, reduced bone marrow cellularity and extravasation of red blood cells into the extra-vascular bone marrow. All CBZ-induced effects were transient and rapidly lost following cessation of treatment. CONCLUSION Short-term administration of CBZ induces rapid, reversible effects on the bone microenvironment in vivo highlighting a potential role in mediating treatment responses.
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Affiliation(s)
| | - Keith D Hunter
- School of Clinical Dentistry, University of Sheffield, Sheffield, UK.
| | - Simon P Robinson
- CR-UK Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, Sutton, Surrey, UK.
| | - Timothy J Graham
- CR-UK Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, Sutton, Surrey, UK.
| | - Eva Corey
- Department of Urology, University of Washington Medical Center, Seattle, WA, USA.
| | - T Neil Dear
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia.
| | - Russell Hughes
- Department of Oncology, University of Sheffield, Sheffield, UK.
| | - Nicola J Brown
- Department of Oncology, University of Sheffield, Sheffield, UK.
| | - Ingunn Holen
- Department of Oncology, University of Sheffield, Sheffield, UK.
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Akbal A, Gökmen F, Gencer M, Inceer BS, Kömürcü E. Mean platelet volume and platelet distribution width can be related to bone mineralization. Osteoporos Int 2014; 25:2291-5. [PMID: 24923794 DOI: 10.1007/s00198-014-2764-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 06/03/2014] [Indexed: 10/25/2022]
Abstract
UNLABELLED Platelets functions are related to bone resorption and formation. The present study aimed at studying the association between platelet function and bone mineralization. We showed that mean platelet volume (MPV) and platelet distribution width (PDW) levels in osteoporosis patients increased. The study also showed that PDW and age independently associated with bone mineralization. INTRODUCTION MPV and PDW are widely used for assessing platelet function. Recently, authors argued that platelet function has an important role in bone mineralization. However, only one study has investigated the relationship between MPV and osteoporosis. We aimed to study the levels of MPV and PDW in postmenopausal osteoporosis. METHODS We investigated 320 bone mineral density (BMD) measurements between the years 2012 and 2013 retrospectively in our clinic. Eighty patients whom chronic diseases are absent and all laboratory findings are complete enrolled in this study. Patients were divided in three groups as an osteoporosis, osteopenia, and normal BMD group. MPV and PDW levels were investigated in these groups. We performed correlation test and linear regression analysis to determine whether there is a relationship between platelet function markers and BMD measurements. RESULTS Eighty patients were divided as an osteoporosis, osteopenia, and normal BMD group. MPV levels and PDW levels in the osteoporosis group were lower than the normal BMD group. PDW was positively correlated with femur total T (FTT) score and lumbar 1-4T (L1-4T) scores. Linear regression analysis showed that age and PDW were independently related to FTT and LTT scores. CONCLUSION Platelet functions are related to the bone mineralization. PDW and MPV have a significant role in the development of postmenopausal osteoporosis.
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Affiliation(s)
- A Akbal
- Department of Physical Medicine and Rehabilitation, Çanakkale Onsekiz Mart University, Çanakkale, Turkey,
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Cheng YH, Hooker RA, Nguyen K, Gerard-O'Riley R, Waning DL, Chitteti BR, Meijome TE, Chua HL, Plett AP, Orschell CM, Srour EF, Mayo LD, Pavalko FM, Bruzzaniti A, Kacena MA. Pyk2 regulates megakaryocyte-induced increases in osteoblast number and bone formation. J Bone Miner Res 2013; 28:1434-45. [PMID: 23362087 PMCID: PMC3663900 DOI: 10.1002/jbmr.1876] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 01/05/2013] [Accepted: 01/11/2013] [Indexed: 12/20/2022]
Abstract
Preclinical and clinical evidence from megakaryocyte (MK)-related diseases suggests that MKs play a significant role in maintaining bone homeostasis. Findings from our laboratories reveal that MKs significantly increase osteoblast (OB) number through direct MK-OB contact and the activation of integrins. We, therefore, examined the role of Pyk2, a tyrosine kinase known to be regulated downstream of integrins, in the MK-mediated enhancement of OBs. When OBs were co-cultured with MKs, total Pyk2 levels in OBs were significantly enhanced primarily because of increased Pyk2 gene transcription. Additionally, p53 and Mdm2 were both decreased in OBs upon MK stimulation, which would be permissive of cell cycle entry. We then demonstrated that OB number was markedly reduced when Pyk2-/- OBs, as opposed to wild-type (WT) OBs, were co-cultured with MKs. We also determined that MKs inhibit OB differentiation in the presence and absence of Pyk2 expression. Finally, given that MK-replete spleen cells from GATA-1-deficient mice can robustly stimulate OB proliferation and bone formation in WT mice, we adoptively transferred spleen cells from these mice into Pyk2-/- recipient mice. Importantly, GATA-1-deficient spleen cells failed to stimulate an increase in bone formation in Pyk2-/- mice, suggesting in vivo the important role of Pyk2 in the MK-induced increase in bone volume. Further understanding of the signaling pathways involved in the MK-mediated enhancement of OB number and bone formation will facilitate the development of novel anabolic therapies to treat bone loss diseases.
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Affiliation(s)
- Ying-Hua Cheng
- Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
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Liang C, Chan KH, Yoon PJ, Lovell MA. Clinicopathological characteristics of extramedullary acute megakaryoblastic leukemia (AMKL): report of a case with initial mastoid presentation and review of literature to compare extramedullary AMKL and non-AMKL cases. Pediatr Dev Pathol 2012; 15:385-92. [PMID: 22667334 DOI: 10.2350/11-12-1124-cr.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Extramedullary acute megakaryoblastic leukemia (AMKL) is a rare neoplasm with a varied clinical presentation. AMKL with initial mastoid presentation has never been reported. The extreme rarity of mastoid AMKL, together with the tendency of extramedullary AMKL to mimic other small blue cell tumors, can create a diagnostic challenge. We report a case of AMKL that initially presented as a mastoid lesion and provide a comprehensive review and analysis that compares the characteristics of extramedullary AMKL and nonmegakaryoblastic acute myeloid leukemia (AML) in reported pediatric cases over the past 30 years. We found that patients with extramedullary AMKL were not only younger than patients without megakaryocytic differentiation but were also limited to those ≤ 2 years of age. In addition, girls predominated in both AMKL and AML MLL(+) groups compared with other types of AML (P = 0.0366 and P = 0.0082). Furthermore, we found that extramedullary AMKL was more likely to involve bone than AML MLL(+) (P < 0.0001) or other types of AML (P = 0.0002). These findings suggest that extramedullary AMKL should be considered in the differential diagnosis of SBCT in children, especially in patients with mastoid or other bony lesions, those ≤ 2 years of age, and female patients.
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Affiliation(s)
- Conan Liang
- Department of Pediatric Otolaryngology, Children's Hospital Colorado, Aurora, CO, USA
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13
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Gruber R. Cell biology of osteoimmunology. Wien Med Wochenschr 2010; 160:438-45. [PMID: 20714814 DOI: 10.1007/s10354-010-0809-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2009] [Accepted: 02/11/2010] [Indexed: 12/27/2022]
Abstract
Osteoimmunology is defined as the research area focusing on the crosstalk between the immune system and the muskoskeletal system. After nearly a decade of research, we are now beginning to understand the basic principles of this crosstalk. It seems that almost all immune cells are capable of communicating with osteoblasts, osteoclasts, and their respective progenitors - and vice versa. Diseases that fall into the category of osteoimmunology including osteoporosis, rheumatoid arthritis, and periodontal disease are of particular significance considering their implications in quality of life, their increased incidence in the population, and socioeconomic issues. To better understand the underlying pathogenesis, the main pathways of the crosstalk between the immune system and the muskoskeletal system need to be uncovered. Our current understanding has already provided the scientific basis for the development of targeted therapies. However, the challenge of future studies is to further decipher this crosstalk at cellular and molecular levels.
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Affiliation(s)
- Reinhard Gruber
- Department of Oral Surgery, Medical University of Vienna, Vienna, Austria,
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