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Kazemi M, Jarrett BY, Parry SA, Thalacker-Mercer AE, Hoeger KM, Spandorfer SD, Lujan ME. Osteosarcopenia in Reproductive-Aged Women with Polycystic Ovary Syndrome: A Multicenter Case-Control Study. J Clin Endocrinol Metab 2020; 105:5866600. [PMID: 32614948 PMCID: PMC7418445 DOI: 10.1210/clinem/dgaa426] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 06/26/2020] [Indexed: 02/07/2023]
Abstract
CONTEXT Osteosarcopenia (loss of skeletal muscle and bone mass and/or function usually associated with aging) shares pathophysiological mechanisms with polycystic ovary syndrome (PCOS). However, the relationship between osteosarcopenia and PCOS remains unclear. OBJECTIVE We evaluated skeletal muscle index% (SMI% = [appendicular muscle mass/weight (kg)] × 100) and bone mineral density (BMD) in PCOS (hyperandrogenism + oligoamenorrhea), and contrasted these musculoskeletal markers against 3 reproductive phenotypes (i): HA (hyperandrogenism + eumenorrhea) (ii); OA (normoandrogenic + oligoamenorrhea) and (iii), controls (normoandrogenic + eumenorrhea). Endocrine predictors of SMI% and BMD were evaluated across the groups. DESIGN, SETTING, AND PARTICIPANTS Multicenter case-control study of 203 women (18-48 years old) in New York State. RESULTS PCOS group exhibited reduced SMI% (mean [95% confidence interval (CI)]; 26.2% [25.1,27.3] vs 28.8% [27.7,29.8]), lower-extremity SMI% (57.6% [56.7,60.0] vs 62.5% [60.3,64.6]), and BMD (1.11 [1.08,1.14] vs 1.17 [1.14,1.20] g/cm2) compared to controls. PCOS group also had decreased upper (0.72 [0.70,0.74] vs 0.77 [0.75,0.79] g/cm2) and lower (1.13 [1.10,1.16] vs 1.19 [1.16,1.22] g/cm2) limb BMD compared to HA. Matsuda index was lower in PCOS vs controls and positively associated with SMI% in all groups (all Ps ≤ 0.05). Only controls showed associations between insulin-like growth factor (IGF) 1 and upper (r = 0.84) and lower (r = 0.72) limb BMD (all Ps < 0.01). Unlike in PCOS, IGF-binding protein 2 was associated with SMI% in controls (r = 0.45) and HA (r = 0.67), and with upper limb BMD (r = 0.98) in HA (all Ps < 0.05). CONCLUSIONS Women with PCOS exhibit early signs of osteosarcopenia when compared to controls likely attributed to disrupted insulin function. Understanding the degree of musculoskeletal deterioration in PCOS is critical for implementing targeted interventions that prevent and delay osteosarcopenia in this clinical population.
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Affiliation(s)
- Maryam Kazemi
- Division of Nutritional Sciences, Human Metabolic Research Unit, Cornell University, Ithaca, NY, US
| | - Brittany Y Jarrett
- Division of Nutritional Sciences, Human Metabolic Research Unit, Cornell University, Ithaca, NY, US
| | - Stephen A Parry
- Cornell Statistical Consulting Unit, Cornell University, Ithaca, NY, US
| | - Anna E Thalacker-Mercer
- Division of Nutritional Sciences, Human Metabolic Research Unit, Cornell University, Ithaca, NY, US
| | - Kathleen M Hoeger
- Department of Obstetrics and Gynecology, University of Rochester Medical Center, Rochester, NY, USA
| | - Steven D Spandorfer
- Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine, Weill Cornell Medicine, New York, NY, US
| | - Marla E Lujan
- Division of Nutritional Sciences, Human Metabolic Research Unit, Cornell University, Ithaca, NY, US
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Hovey O, Pasha R, Lehmann Z, Pineault N. Insights into the Hematopoietic Regulatory Activities of Osteoblast by Secretomics. Proteomics 2020; 20:e2000036. [PMID: 32666692 DOI: 10.1002/pmic.202000036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/22/2020] [Indexed: 11/09/2022]
Abstract
Osteoblasts are a key component of the endosteal hematopoietic stem cell (HSC) niche and are recognized with strong hematopoietic supporting activity. Similarly, mesenchymal stromal cells (MSC)-derived osteoblast (M-OST) conditioned media (OCM) enhances the growth of hematopoietic progenitors in culture and modulate their engraftment activity. We aimed to characterize the hematopoietic supporting activity of OCM by comparing the secretome of M-OST to that of their precursor. Over 300 proteins were quantified by mass spectroscopy in media conditioned with MSC or M-OST, with 47 being differentially expressed. Included were growth factors, extracellular matrix (ECM) proteins and proteins from the complement pathways. The functional contribution of selected proteins on the growth and differentiation of cord blood (CB) progenitors was tested. Secreted Protein Acidic and Rich in Cysteine (SPARC) and Galectin 3 (Gal3) had little impact on the growth of CB cells in serum-free medium (SFM). In contrast, inhibition of the complement 3 A receptor (C3a-R) present on CB progenitors significantly reduced the growth of CD34+ cells in OCM cultures but not in SFM. These results provide new insights into changes in factors released by MSC undergoing osteoblast differentiation, and on paracrine factors that are partially responsible for the hematopoietic supporting activity of osteoblasts. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Owen Hovey
- Canadian Blood Services, Centre for Innovation, Ottawa, Ontario, Canada
- Biochemistry, Microbiology and Immunology Department, University of Ottawa, Ottawa, Canada
| | - Roya Pasha
- Canadian Blood Services, Centre for Innovation, Ottawa, Ontario, Canada
- Biochemistry, Microbiology and Immunology Department, University of Ottawa, Ottawa, Canada
| | - Zoe Lehmann
- Canadian Blood Services, Centre for Innovation, Ottawa, Ontario, Canada
- Biochemistry, Microbiology and Immunology Department, University of Ottawa, Ottawa, Canada
| | - Nicolas Pineault
- Canadian Blood Services, Centre for Innovation, Ottawa, Ontario, Canada
- Biochemistry, Microbiology and Immunology Department, University of Ottawa, Ottawa, Canada
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3
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Xi G, Demambro VE, D’Costa S, Xia SK, Cox ZC, Rosen CJ, Clemmons DR. Estrogen Stimulation of Pleiotrophin Enhances Osteoblast Differentiation and Maintains Bone Mass in IGFBP-2 Null Mice. Endocrinology 2020; 161:5805123. [PMID: 32168373 PMCID: PMC7069688 DOI: 10.1210/endocr/bqz007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 03/12/2020] [Indexed: 12/22/2022]
Abstract
Insulin-like growth factor binding protein-2 (IGFBP-2) stimulates osteoblast differentiation but only male Igfbp2 null mice have a skeletal phenotype. The trophic actions of IGFBP-2 in bone are mediated through its binding to receptor tyrosine phosphatase beta (RPTPβ). Another important ligand for RPTPβ is pleiotrophin (PTN), which also stimulates osteoblast differentiation. We determined the change in PTN and RPTPβ in Igfbp2-/- mice. Analysis of whole bone mRNA in wild-type and knockout mice revealed increased expression of Ptn. Rptpβ increased in gene-deleted animals with females having greater expression than males. Knockdown of PTN expression in osteoblasts in vitro inhibited differentiation, and addition of PTN to the incubation medium rescued the response. Estradiol stimulated PTN secretion and PTN knockdown blocked estradiol-stimulated differentiation. PTN addition to IGFBP-2 silenced osteoblast stimulated differentiation, and an anti-fibronectin-3 antibody, which inhibits PTN binding to RPTPβ, inhibited this response. Estrogen stimulated PTN secretion and downstream signaling in the IGFBP-2 silenced osteoblasts and these effects were inhibited with anti-fibronectin-3. Administration of estrogen to wild-type and Igfbp2-/- male mice stimulated an increase in both areal bone mineral density and trabecular bone volume fraction but the increase was significantly greater in the Igfbp2-/- animals. Estrogen also stimulated RPTPβ expression in the null mice. We conclude that loss of IGFBP-2 expression is accompanied by upregulation of PTN and RPTPβ expression in osteoblasts, that the degree of increase is greater in females due to estrogen secretion, and that this compensatory change may account for some component of the maintenance of normal bone mass in female mice.
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Affiliation(s)
- Gang Xi
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
| | | | - Susan D’Costa
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
| | - Shalier K Xia
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
| | - Zach C Cox
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
| | | | - David R Clemmons
- Department of Medicine UNC School of Medicine Chapel Hill, North Carolina
- Correspondence: David R. Clemmons, MD, CB#7170, 8024 Burnett-Womack, Division of Endocrinology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7170. E-mail:
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4
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Diao S, Yang H, Cao Y, Yang D, Fan Z. IGF2 enhanced the osteo-/dentinogenic and neurogenic differentiation potentials of stem cells from apical papilla. J Oral Rehabil 2019; 47 Suppl 1:55-65. [PMID: 31291686 DOI: 10.1111/joor.12859] [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: 01/20/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 12/27/2022]
Abstract
OBJECTIVES In dental tissue engineering, niche is important for maintaining stem cell function and regenerating the dental tissues. However, there is limited knowledge for the growth factors in niche to maintain the function of stem cells. In this study, we investigated the effect of IGF2, a growth factor in stem cells from apical papilla (SCAPs) niche, on differentiation and proliferation potentials of SCAPs. MATERIALS AND METHODS Recombinant human IGF2 protein (rhIGF2) was used. Cell counting kit-8 assay, Carboxyfluorescein succinimidyl ester assay, alkaline phosphatase (ALP) activity, Alizarin Red staining, quantitative calcium analysis, immunofluorescence staining and real-time RT-PCR were performed to investigate the cell proliferation and differentiation potentials of SCAPs. And proteomic analysis was used to identify the differential secreted proteins. RESULTS By ALP activity assay, we found that 5 ng/mL rhIGF2 might be the optimal concentration for treatment. Then, Alizarin Red staining, quantitative calcium analysis and osteogenesis-related gene expression results showed that 5 ng/mL rhIGF2 could enhance the osteo-/dentinogenic differentiation potentials in SCAPs. Immunofluorescence staining and real-time RT-PCR results showed that neurogenic markers were significantly induced by 5 ng/mL rhIGF2 in SCAPs. Then, CCK-8 assay and CFSE assay results showed that 5 ng/mL rhIGF2 could enhance the cell proliferation in SCAPs. Furthermore, proteomic analysis showed that IGF2 could induce some secreted proteins which function related to the osteogenesis, neurogenesis and cell proliferation. CONCLUSIONS Our results identified that IGF2 might be the potential mediator in niche to promote SCAP function and dental tissue regeneration.
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Affiliation(s)
- Shu Diao
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China.,Department of Pediatric dentistry, Capital Medical University School of Stomatology, Beijing, China
| | - Haoqing Yang
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China
| | - Yangyang Cao
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China
| | - Dongmei Yang
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China.,Department of Pediatric dentistry, Capital Medical University School of Stomatology, Beijing, China
| | - Zhipeng Fan
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China
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Al-Khafaji H, Noer PR, Alkharobi H, Alhodhodi A, Meade J, El-Gendy R, Oxvig C, Beattie J. A characteristic signature of insulin-like growth factor (IGF) axis expression during osteogenic differentiation of human dental pulp cells (hDPCs): Potential co-ordinated regulation of IGF action. Growth Horm IGF Res 2018; 42-43:14-21. [PMID: 30071469 PMCID: PMC6259625 DOI: 10.1016/j.ghir.2018.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 01/09/2023]
Abstract
The IGF axis is represented by two growth factors (IGF1 and IGF2), two cognate cell surface receptors (IGF1R and IGF2R), six soluble high affinity IGF binding proteins (IGFBP1-6) and several IGFBP proteases. IGF1 and IGF2 are present at high concentrations in bone and play a crucial role in the maintenance and differentiation of both foetal and adult skeleton. In order to understand the role of the IGF axis in bone and other tissues it is necessary to profile the expression and activity of all genes in the axis together with the activity of relevant ancillary proteins (including IGFBP proteases). In the current report we used differentiating human dental pulp cells (hDPC) to examine the expression and activity of the IGF axis during osteogenic differentiation of these cells. We found that, with the exception of IGF1 and IGFBP1, all components of the IGF axis are expressed in hDPCs. IGFBP-4 is the most abundantly expressed IGFBP species at both mRNA and protein levels under both basal and osteogenic conditions. Although we found no difference in IGFBP-4 expression under osteogenic conditions, we report increased expression and activity of pregnancy associated plasma protein-A (PAPP-A - an IGFBP-4 proteinase) leading to increased IGFBP-4 proteolysis in differentiating cell cultures. Further to this we report increased expression of IGF-2 (an activator of PAPP-A), and decreased expression of stanniocalcin-2 (STC2- a recently discovered inhibitor of PAPP-A) under osteogenic conditions. We also demonstrate that STC2 and PAPP-A are able to form complexes in hDPC conditioned medium indicating the potential for regulation of IGFBP-4 proteolysis through this mechanism. We suggest that these changes in the expression and activity of the IGF axis may represent part of an osteogenic signature characteristic of differentiating hDPCs.
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Affiliation(s)
- Hasanain Al-Khafaji
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom
| | - Pernille R Noer
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - Hanna Alkharobi
- Department of Oral Biology, Dental College, King AbdulAziz University, Jeddah, Saudi Arabia
| | - Aishah Alhodhodi
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom
| | - Josephine Meade
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom
| | - Reem El-Gendy
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom; Department of Oral Pathology, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark
| | - James Beattie
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom.
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A peptide containing the receptor binding site of insulin-like growth factor binding protein-2 enhances bone mass in ovariectomized rats. Bone Res 2018; 6:23. [PMID: 30109160 PMCID: PMC6089876 DOI: 10.1038/s41413-018-0024-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 05/31/2018] [Accepted: 06/15/2018] [Indexed: 12/27/2022] Open
Abstract
Male Igfbp2−/− mice have a significant reduction in bone mass and administration of a peptide that contains the insulin-like growth factor binding protein-2(IGFBP-2) receptor-binding domain stimulates bone formation in these animals. Female Igfbp2−/− mice do not have this phenotype but following ovariectomy (OVX) lose more bone than OVX wild-type mice. This suggests that in the absence of estrogen, IGFBP-2 is required to maintain bone mass. Therefore these studies were undertaken to determine if this peptide could stimulate bone acquisition in OVX rats. OVX rats were divided into seven treatment groups: sham animals, OVX animals, OVX animals receiving a control scrambled peptide, or one of three doses of the active peptide termed PEG-HBD-1 (0.7, 2, and 6 mg·kg-1) and an OVX group receiving parathyroid hormone (PTH) (50 µg·kg-1 per day). The peptides were administered for 8 weeks. DXA revealed a significant reduction in femoral and tibial areal bone mineral density (aBMD) after OVX, whereas treatment with the high-dose peptide increased aBMD by 6.2% ± 2.4% (P < 0.01) compared to control peptide; similar to the increase noted with PTH (5.6% ± 3.0%, P < 0.01). Similar increases were noted with two lower doses of the peptide (3.8% ± 1.5%, P < 0.05 for low dose; 3.1% ± 1.6%, P = 0.07 for middle dose). Micro CT showed that the OVX control peptide animals had reductions of 41% and 64% in femoral trabecular BV/TV and trabecular number, respectively. All three doses of the peptide increased bone volume/total volume (BV/TV) significantly, while the low and middle doses increased trabecular number. Cortical BV/TV and thickness at the midshaft increased significantly with each dose of peptide (18.9% ± 9.8%, P < 0.01 and 14.2% ± 7.9%, P < 0.01 for low dose; 23.7% ± 10.7%, P < 0.001 and 15.8% ± 6.1%, P < 0.001 for middle dose; 19.0% ± 6.9%, P < 0.01 and 16.2% ± 9.7%, P < 0.001 for high dose) and with PTH (25.8% ± 9.2%, P < 0.001 and 19.4% ± 8.8%, P < 0.001). Histomorphometry showed that the lowest dose of peptide stimulated BV/TV, trabecular thickness, mineral apposition rate (MAR), bone formation rate/bone surface (BFR/BS), number of osteoblasts/bone perimeter (N.ob/B.pm), and decreased osteoclast surface/bone perimeter (Oc.S/B.Pm). The highest dose stimulated each of these parameters except MAR and BFR/BS. Thus, the heparin-binding domain receptor region of IGFBP-2 accounts for its anabolic activity in bone. Importantly, this peptide enhances bone mass in estrogen-deficient animals. An experimental peptide stimulates bone acquisition in female rats who have had their ovaries removed, raising the prospect a new drug for osteoporosis. IGFBP-2 is an insulin-like growth factor (IGF) binding protein, which regulates the amount of IGF-I and II that are transported out of the blood and are available to influence the growth and proliferation of bone-producing osteoblasts. Previous studies have suggested that IGFBP-2 is required to maintain bone mass in the absence of estrogen, and that a 13 amino acid peptide (HBD1) from the core of the protein could provide a substitute for it. In this study, David Clemmons at the University of North Carolina at Chapel Hill and his colleagues demonstrate that injecting the peptide into ovariectomized female rats prompts significant increases in bone mass, whereas control animals lost bone.
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7
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Clemmons DR. Role of IGF-binding proteins in regulating IGF responses to changes in metabolism. J Mol Endocrinol 2018; 61:T139-T169. [PMID: 29563157 DOI: 10.1530/jme-18-0016] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 03/21/2018] [Indexed: 12/22/2022]
Abstract
The IGF-binding protein family contains six members that share significant structural homology. Their principal function is to regulate the actions of IGF1 and IGF2. These proteins are present in plasma and extracellular fluids and regulate access of both IGF1 and II to the type I IGF receptor. Additionally, they have functions that are independent of their ability to bind IGFs. Each protein is regulated independently of IGF1 and IGF2, and this provides an important mechanism by which other hormones and physiologic variables can regulate IGF actions indirectly. Several members of the family are sensitive to changes in intermediary metabolism. Specifically the presence of obesity/insulin resistance can significantly alter the expression of these proteins. Similarly changes in nutrition or catabolism can alter their synthesis and degradation. Multiple hormones such as glucocorticoids, androgens, estrogen and insulin regulate IGFBP synthesis and bioavailability. In addition to their ability to regulate IGF access to receptors these proteins can bind to distinct cell surface proteins or proteins in extracellular matrix and several cellular functions are influenced by these interactions. IGFBPs can be transported intracellularly and interact with nuclear proteins to alter cellular physiology. In pathophysiologic states, there is significant dysregulation between the changes in IGFBP synthesis and bioavailability and changes in IGF1 and IGF2. These discordant changes can lead to marked alterations in IGF action. Although binding protein physiology and pathophysiology are complex, experimental results have provided an important avenue for understanding how IGF actions are regulated in a variety of physiologic and pathophysiologic conditions.
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Affiliation(s)
- David R Clemmons
- Department of MedicineUNC School of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
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8
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Beattie J, Al-Khafaji H, Noer PR, Alkharobi HE, Alhodhodi A, Meade J, El-Gendy R, Oxvig C. Insulin- like Growth Factor-Binding Protein Action in Bone Tissue: A Key Role for Pregnancy- Associated Plasma Protein-A. Front Endocrinol (Lausanne) 2018; 9:31. [PMID: 29503631 PMCID: PMC5820303 DOI: 10.3389/fendo.2018.00031] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 01/23/2018] [Indexed: 11/13/2022] Open
Abstract
The insulin-like growth factor (IGF) axis is required for the differentiation, development, and maintenance of bone tissue. Accordingly, dysregulation of this axis is associated with various skeletal pathologies including growth abnormalities and compromised bone structure. It is becoming increasingly apparent that the action of the IGF axis must be viewed holistically taking into account not just the actions of the growth factors and receptors, but also the influence of soluble high affinity IGF binding proteins (IGFBPs).There is a recognition that IGFBPs exert IGF-dependent and IGF-independent effects in bone and other tissues and that an understanding of the mechanisms of action of IGFBPs and their regulation in the pericellular environment impact critically on tissue physiology. In this respect, a group of IGFBP proteinases (which may be considered as ancillary members of the IGF axis) play a crucial role in regulating IGFBP function. In this model, cleavage of IGFBPs by specific proteinases into fragments with lower affinity for growth factor(s) regulates the partition of IGFs between IGFBPs and cell surface IGF receptors. In this review, we examine the importance of IGFBP function in bone tissue with special emphasis on the role of pregnancy associated plasma protein-A (PAPP-A). We examine the function of PAPP-A primarily as an IGFBP-4 proteinase and present evidence that PAPP-A induced cleavage of IGFBP-4 is potentially a key regulatory step in bone metabolism. We also highlight some recent findings with regard to IGFBP-2 and IGFBP-5 (also PAPP-A substrates) function in bone tissue and briefly discuss the actions of the other three IGFBPs (-1, -3, and -6) in this tissue. Although our main focus will be in bone we will allude to IGFBP activity in other cells and tissues where appropriate.
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Affiliation(s)
- James Beattie
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom
- *Correspondence: James Beattie,
| | - Hasanain Al-Khafaji
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom
| | - Pernille R. Noer
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Hanaa Esa Alkharobi
- Department of Oral Biology, Dental College, King AbdulAziz University, Jeddah, Saudi Arabia
| | - Aishah Alhodhodi
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom
| | - Josephine Meade
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom
| | - Reem El-Gendy
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, University of Leeds, St James University Hospital, Leeds, United Kingdom
- Department of Oral Pathology, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt
| | - Claus Oxvig
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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9
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Alkharobi H, Alhodhodi A, Hawsawi Y, Alkafaji H, Devine D, El-Gendy R, Beattie J. IGFBP-2 and -3 co-ordinately regulate IGF1 induced matrix mineralisation of differentiating human dental pulp cells. Stem Cell Res 2016; 17:517-522. [PMID: 27776273 PMCID: PMC5153425 DOI: 10.1016/j.scr.2016.09.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 09/22/2016] [Accepted: 09/22/2016] [Indexed: 01/07/2023] Open
Abstract
Human dental pulp cells (DPCs), which are known to contain a subset of stem cells capable of reforming a dentin and pulp-like complex upon in vivo transplantation, were isolated from third molars of three healthy donors and differentiated to a matrix mineralisation phenotype using by culture in dexamethasone and l-ascorbic acid. qRT-PCR analysis of insulin-like growth factor ( IGF) axis gene expression indicated that all genes, except insulin-like growth factor 1 (IGF1) and insulin-like growth factor binding protein-1 ( IGFBP-1), were expressed in DPCs. During differentiation upregulation of insulin-like growth factor binding protein-2 (IGFBP-2) and downregulation of insulin-like growth factor binding protein-3 (IGFBP-3) expression was observed. Changes in IGFBP-2 and IGFBP-3 mRNA expression were confirmed at the protein level by ELISA of DPC conditioned medium functional analysis indicated that IGF1 stimulated the differentiation of DPCs and that the activity of the growth factor was enhanced by pre-complexation with IGFBP-2 but inhibited by pre-complexation with IGFBP-3. Therefore changes in IGFBP-2 and -3 expression during differentiation form part of a co-ordinated functional response to enhance the pro-differentiative action of IGF1 and represent a novel mechanism for the regulation of DPC differentiation.
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Affiliation(s)
- Hanaa Alkharobi
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, St James University Hospital, University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Aishah Alhodhodi
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, St James University Hospital, University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Yousef Hawsawi
- Dept. of Medical Breast Oncology, MD Anderson Cancer Research Centre, University of Texas, Houston, United States
| | - Hasanain Alkafaji
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, St James University Hospital, University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Deirdre Devine
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, St James University Hospital, University of Leeds, Leeds LS9 7TF, United Kingdom
| | - Reem El-Gendy
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, St James University Hospital, University of Leeds, Leeds LS9 7TF, United Kingdom; Dept. of Oral Pathology, Faculty of Dentistry, Suez Canal University, Ismailia, Egypt.
| | - James Beattie
- Division of Oral Biology, Leeds School of Dentistry, Level 7 Wellcome Trust Brenner Building, St James University Hospital, University of Leeds, Leeds LS9 7TF, United Kingdom.
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10
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DeMambro VE, Le PT, Guntur AR, Maridas DE, Canalis E, Nagano K, Baron R, Clemmons DR, Rosen CJ. Igfbp2 Deletion in Ovariectomized Mice Enhances Energy Expenditure but Accelerates Bone Loss. Endocrinology 2015; 156:4129-40. [PMID: 26230658 PMCID: PMC4606757 DOI: 10.1210/en.2014-1452] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Previously, we reported sexually dimorphic bone mass and body composition phenotypes in Igfbp2(-/-) mice (-/-), where male mice exhibited decreased bone and increased fat mass, whereas female mice displayed increased bone but no changes in fat mass. To investigate the interaction between IGF-binding protein (IGFBP)-2 and estrogen, we subjected Igfbp2 -/- and +/+ female mice to ovariectomy (OVX) or sham surgery at 8 weeks of age. At 20 weeks of age, mice underwent metabolic cage analysis and insulin tolerance tests before killing. At harvest, femurs were collected for microcomputed tomography, serum for protein levels, brown adipose tissue (BAT) and inguinal white adipose tissue (IWAT) adipose depots for histology, gene expression, and mitochondrial respiration analysis of whole tissue. In +/+ mice, serum IGFBP-2 dropped 30% with OVX. In the absence of IGFBP-2, OVX had no effect on preformed BAT; however, there was significant "browning" of the IWAT depot coinciding with less weight gain, increased insulin sensitivity, lower intraabdominal fat, and increased bone loss due to higher resorption and lower formation. Likewise, after OVX, energy expenditure, physical activity and BAT mitochondrial respiration were decreased less in the OVX-/- compared with OVX+/+. Mitochondrial respiration of IWAT was reduced in OVX+/+ yet remained unchanged in OVX-/- mice. These changes were associated with significant increases in Fgf21 and Foxc2 expression, 2 proteins known for their insulin sensitizing and browning of WAT effects. We conclude that estrogen deficiency has a profound effect on body and bone composition in the absence of IGFBP-2 and may be related to changes in fibroblast growth factor 21.
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Affiliation(s)
- Victoria E DeMambro
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Phuong T Le
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Anyonya R Guntur
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - David E Maridas
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Ernesto Canalis
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Kenichi Nagano
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Roland Baron
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - David R Clemmons
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
| | - Clifford J Rosen
- Maine Medical Center Research Institute (V.E.M., P.T.L., A.R.G., D.E.M., C.J.R.), Scarborough, Maine 04074; Departments of Orthopedic Surgery and Medicine (E.C.), University of Connecticut Health Center, Farmington, Connecticut 06032; Department of Medicine (K.N., R.B.), Harvard Medical School and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Harvard University, Boston, Massachusetts 02115; and University of North Carolina (D.R.C.), Chapel Hill, North Carolina 27514
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11
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Hashimoto A, Yamaguchi Y, Chiu LD, Morimoto C, Fujita K, Takedachi M, Kawata S, Murakami S, Tamiya E. Time-lapse Raman imaging of osteoblast differentiation. Sci Rep 2015; 5:12529. [PMID: 26211729 PMCID: PMC4515588 DOI: 10.1038/srep12529] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 07/01/2015] [Indexed: 11/23/2022] Open
Abstract
Osteoblastic mineralization occurs during the early stages of bone formation. During this mineralization, hydroxyapatite (HA), a major component of bone, is synthesized, generating hard tissue. Many of the mechanisms driving biomineralization remain unclear because the traditional biochemical assays used to investigate them are destructive techniques incompatible with viable cells. To determine the temporal changes in mineralization-related biomolecules at mineralization spots, we performed time-lapse Raman imaging of mouse osteoblasts at a subcellular resolution throughout the mineralization process. Raman imaging enabled us to analyze the dynamics of the related biomolecules at mineralization spots throughout the entire process of mineralization. Here, we stimulated KUSA-A1 cells to differentiate into osteoblasts and conducted time-lapse Raman imaging on them every 4 hours for 24 hours, beginning 5 days after the stimulation. The HA and cytochrome c Raman bands were used as markers for osteoblastic mineralization and apoptosis. From the Raman images successfully acquired throughout the mineralization process, we found that β-carotene acts as a biomarker that indicates the initiation of osteoblastic mineralization. A fluctuation of cytochrome c concentration, which indicates cell apoptosis, was also observed during mineralization. We expect time-lapse Raman imaging to help us to further elucidate osteoblastic mineralization mechanisms that have previously been unobservable.
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Affiliation(s)
- Aya Hashimoto
- Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshinori Yamaguchi
- Institute of Photonics and Biomedicine, Graduate School of Science, East China University of Science and Technology, 130 Meilong Rd., Shanghai, 200237, China
| | - Liang-da Chiu
- Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Chiaki Morimoto
- Department of Periodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Katsumasa Fujita
- Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masahide Takedachi
- Department of Periodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Satoshi Kawata
- Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shinya Murakami
- Department of Periodontology, Graduate School of Dentistry, Osaka University, 1-8 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Eiichi Tamiya
- Department of Applied Physics, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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12
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Ding W, Li J, Singh J, Alif R, Vazquez-Padron RI, Gomes SA, Hare JM, Shehadeh LA. miR-30e targets IGF2-regulated osteogenesis in bone marrow-derived mesenchymal stem cells, aortic smooth muscle cells, and ApoE-/- mice. Cardiovasc Res 2015; 106:131-42. [PMID: 25678587 DOI: 10.1093/cvr/cvv030] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
AIMS Activation of an osteogenic transcriptional program contributes to the initiation of aortic calcification in atherosclerosis. The role of microRNAs in regulating aortic calcification is understudied. We tested the hypothesis that miR-30e regulates an osteogenic program in bone marrow-derived mesenchymal stem cells (MSCs), aortic smooth muscle cells (SMCs), and ApoE(-/-) mice. METHODS AND RESULTS In aortas of wild-type mice, we found that miR-30e is highly expressed in medial SMCs. In aortas of old ApoE(-/-) mice, we found that miR-30e transcripts are down-regulated in an inverse relation to the osteogenic markers Runx2, Opn, and Igf2. In vitro, miR-30e over-expression reduced the proliferation of MSCs and SMCs while increasing adipogenic differentiation of MSCs and smooth muscle differentiation of SMCs. In MSCs and SMCs over-expressing miR-30e, microarrays and qPCR showed repression of an osteogenic gene panel including Igf2. Inhibiting miR-30e in MSCs increased Igf2 transcripts. In SMCs, IGF2 recombinant protein rescued miR-30e-repressed osteogenic differentiation. Luciferase and mutagenesis assays showed binding of miR-30e to a novel and essential site at the 3'UTR of Igf2. In ApoE(-/-) mice, injections of antimiR-30e oligos increased Igf2 expression in the aortas and livers and significantly enhanced OPN protein expression and calcium deposition in aortic valves. CONCLUSION miR-30e represses the osteogenic program in MSCs and SMCs by targeting IGF2 and drives their differentiation into adipogenic or smooth muscle lineage, respectively. Our data suggest that down-regulation of miR-30e in aortas with age and atherosclerosis triggers vascular calcification. The miR-30e pathway plays an important regulatory role in vascular diseases.
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Affiliation(s)
- Wen Ding
- Department of Molecular and Cellular Pharmacology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Jihe Li
- Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA Department of Medicine, Division of Cardiology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Jayanti Singh
- Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA Department of Medicine, Division of Cardiology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Razan Alif
- Department of Biochemistry, University of Miami, Coral Gables, FL 33136, USA
| | - Roberto I Vazquez-Padron
- Department of Surgery, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA Vascular Biology Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Samirah A Gomes
- Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Joshua M Hare
- Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA Department of Medicine, Division of Cardiology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
| | - Lina A Shehadeh
- Interdisciplinary Stem Cell Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA Department of Medicine, Division of Cardiology, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA Vascular Biology Institute, University of Miami Leonard M. Miller School of Medicine, Miami, FL 33136, USA
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13
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Yau SW, Azar WJ, Sabin MA, Werther GA, Russo VC. IGFBP-2 - taking the lead in growth, metabolism and cancer. J Cell Commun Signal 2015; 9:125-42. [PMID: 25617050 DOI: 10.1007/s12079-015-0261-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 01/12/2015] [Indexed: 10/24/2022] Open
Abstract
The activity of the Insulin-like Growth Factors (IGFs) ligands elicited via their receptors and transduced by various intracellular signal pathways is modulated by the IGF Binding Proteins (IGFBPs). Among all the IGFBPs, IGFBP-2 has been implicated in the regulation of IGF activity in most tissue and organs. Besides binding to IGFs in the circulation these IGF-regulatory activities of IGFBP-2 involve interactions with components of the extracellular matrix, cell surface proteoglycans and integrin receptors. In addition to these local peri-cellular activities, IGFBP-2 exerts other key functions within the nucleus, where IGFBP-2 directly or indirectly promotes transcriptional activation of specific genes. All of these IGFBP-2 activities, intrinsic or dependent on IGFs, contribute to its functional roles in growth/development, metabolism and malignancy as evidenced by studies in IGFBP-2 animal models and also by many in vitro studies. Finally, preclinical studies have demonstrated that IGFBP-2 administration can be beneficial in improving metabolic responses (inhibition of adipogenesis and enhanced insulin sensitivity), while blockade of IGFBP-2 appears to be an effective approach to inhibiting tumour growth and metastasis.
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Affiliation(s)
- Steven W Yau
- Deparment of Cell Biology, Hormone Research, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia
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14
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Xi G, Wai C, DeMambro V, Rosen CJ, Clemmons DR. IGFBP-2 directly stimulates osteoblast differentiation. J Bone Miner Res 2014; 29:2427-38. [PMID: 24839202 PMCID: PMC5117190 DOI: 10.1002/jbmr.2282] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/13/2014] [Accepted: 05/15/2014] [Indexed: 02/07/2023]
Abstract
Insulin-like growth factor binding protein 2 (IGFBP-2) is important for acquisition of normal bone mass in mice; however, the mechanism by which IGFBP-2 functions is not defined. These studies investigated the role of IGFBP-2 in stimulating osteoblast differentiation. MC-3T3 preosteoblasts expressed IGFBP-2, and IGFBP-2 knockdown resulted in a substantial delay in osteoblast differentiation, reduced osteocalcin expression and Alizarin red staining. These findings were replicated in primary calvarial osteoblasts obtained from IGFBP-2(-/-) mice, and addition of IGFBP-2 rescued the differentiation program. In contrast, overexpression of IGFBP-2 accelerated the time course of differentiation as well as increasing the total number of differentiating cells. By day 6, IGFBP-2-overexpressing cells expressed twice as much osteocalcin as control cultures and this difference persisted. To determine the mechanism by which IGFBP-2 functions, the interaction between IGFBP-2 and receptor tyrosine phosphatase β (RPTPβ) was examined. Disruption of this interaction inhibited the ability of IGFBP-2 to stimulate AKT activation and osteoblast differentiation. Knockdown of RPTPβ enhanced osteoblast differentiation, whereas overexpression of RPTPβ was inhibitory. Adding back IGFBP-2 to RPTPβ-overexpressing cells was able to rescue cell differentiation via enhancement of AKT activation. To determine the region of IGFBP-2 that mediated this effect, an IGFBP-2 mutant that contained substitutions of key amino acids in the heparin-binding domain-1 (HBD-1) was prepared. This mutant had a major reduction in its ability to stimulate differentiation of calvarial osteoblasts from IGFBP-2(-/-) mice. Addition of a synthetic peptide that contained the HBD-1 sequence to calvarial osteoblasts from IGFBP-2(-/-) mice rescued differentiation and osteocalcin expression. In summary, the results clearly demonstrate that IGFBP-2 stimulates osteoblast differentiation and that this effect is mediated through its heparin-binding domain-1 interacting with RPTPβ. The results suggest that stimulation of differentiation is an important mechanism by which IGFBP-2 regulates the acquisition of normal bone mass in mice.
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Affiliation(s)
- Gang Xi
- Department of Medicine, University of North Carolina, Chapel Hill, NC, USA
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15
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Al-Kharobi H, El-Gendy R, Devine DA, Beattie J. The role of the insulin‑like growth factor (IGF) axis in osteogenic and odontogenic differentiation. Cell Mol Life Sci 2014; 71:1469-76. [PMID: 24232361 PMCID: PMC11113200 DOI: 10.1007/s00018-013-1508-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Accepted: 10/25/2013] [Indexed: 11/28/2022]
Abstract
The insulin-like growth factor (IGF) axis is a multicomponent molecular network which has important biological functions in the development and maintenance of differentiated tissue function(s). One of the most important functions of the IGF axis is the control of skeletal tissue metabolism by the finely tuned regulation of the process of osteogenesis. To achieve this, the IGF axis controls the activity of several cell types—osteoprogenitor cells, osteoblasts, osteocytes and osteoclasts to achieve the co-ordinated development of appropriate hard tissue structure and associated matrix deposition. In addition, there is an increasing awareness that the IGF axis also plays a role in the process of odontogenesis (tooth formation). In this review, we highlight some of the key findings in both of these areas. A further understanding of the role of the IGF axis in hard tissue biology may contribute to tissue regeneration strategies in cases of skeletal tissue trauma.
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Affiliation(s)
- H. Al-Kharobi
- Leeds University School of Dentistry, University of Leeds, Clarendon Way, Leeds, LS2 9LU UK
| | - R. El-Gendy
- Leeds University School of Dentistry, University of Leeds, Clarendon Way, Leeds, LS2 9LU UK
| | - D. A. Devine
- Leeds University School of Dentistry, University of Leeds, Clarendon Way, Leeds, LS2 9LU UK
| | - J. Beattie
- Leeds University School of Dentistry, University of Leeds, Clarendon Way, Leeds, LS2 9LU UK
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16
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Benisch P, Schilling T, Klein-Hitpass L, Frey SP, Seefried L, Raaijmakers N, Krug M, Regensburger M, Zeck S, Schinke T, Amling M, Ebert R, Jakob F. The transcriptional profile of mesenchymal stem cell populations in primary osteoporosis is distinct and shows overexpression of osteogenic inhibitors. PLoS One 2012; 7:e45142. [PMID: 23028809 PMCID: PMC3454401 DOI: 10.1371/journal.pone.0045142] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/13/2012] [Indexed: 12/11/2022] Open
Abstract
Primary osteoporosis is an age-related disease characterized by an imbalance in bone homeostasis. While the resorptive aspect of the disease has been studied intensely, less is known about the anabolic part of the syndrome or presumptive deficiencies in bone regeneration. Multipotent mesenchymal stem cells (MSC) are the primary source of osteogenic regeneration. In the present study we aimed to unravel whether MSC biology is directly involved in the pathophysiology of the disease and therefore performed microarray analyses of hMSC of elderly patients (79–94 years old) suffering from osteoporosis (hMSC-OP). In comparison to age-matched controls we detected profound changes in the transcriptome in hMSC-OP, e.g. enhanced mRNA expression of known osteoporosis-associated genes (LRP5, RUNX2, COL1A1) and of genes involved in osteoclastogenesis (CSF1, PTH1R), but most notably of genes coding for inhibitors of WNT and BMP signaling, such as Sclerostin and MAB21L2. These candidate genes indicate intrinsic deficiencies in self-renewal and differentiation potential in osteoporotic stem cells. We also compared both hMSC-OP and non-osteoporotic hMSC-old of elderly donors to hMSC of ∼30 years younger donors and found that the transcriptional changes acquired between the sixth and the ninth decade of life differed widely between osteoporotic and non-osteoporotic stem cells. In addition, we compared the osteoporotic transcriptome to long term-cultivated, senescent hMSC and detected some signs for pre-senescence in hMSC-OP. Our results suggest that in primary osteoporosis the transcriptomes of hMSC populations show distinct signatures and little overlap with non-osteoporotic aging, although we detected some hints for senescence-associated changes. While there are remarkable inter-individual variations as expected for polygenetic diseases, we could identify many susceptibility genes for osteoporosis known from genetic studies. We also found new candidates, e.g. MAB21L2, a novel repressor of BMP-induced transcription. Such transcriptional changes may reflect epigenetic changes, which are part of a specific osteoporosis-associated aging process.
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Affiliation(s)
- Peggy Benisch
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Tatjana Schilling
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Ludger Klein-Hitpass
- Institute of Cell Biology (Tumor Research), University Hospital Essen, Essen, Germany
| | - Sönke P. Frey
- Department of Trauma, Hand-, Plastic- and Reconstructive Surgery, University Hospital of Wuerzburg, Wuerzburg, Germany
| | - Lothar Seefried
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Nadja Raaijmakers
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Melanie Krug
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Martina Regensburger
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Sabine Zeck
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Regina Ebert
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
| | - Franz Jakob
- Orthopedic Center for Musculoskeletal Research, University of Wuerzburg, Wuerzburg, Germany
- * E-mail:
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17
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Kristensen LP, Chen L, Nielsen MO, Qanie DW, Kratchmarova I, Kassem M, Andersen JS. Temporal profiling and pulsed SILAC labeling identify novel secreted proteins during ex vivo osteoblast differentiation of human stromal stem cells. Mol Cell Proteomics 2012; 11:989-1007. [PMID: 22801418 DOI: 10.1074/mcp.m111.012138] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
It is well established that bone forming cells (osteoblasts) secrete proteins with autocrine, paracrine, and endocrine function. However, the identity and functional role for the majority of these secreted and differentially expressed proteins during the osteoblast (OB) differentiation process, is not fully established. To address these questions, we quantified the temporal dynamics of the human stromal (mesenchymal, skeletal) stem cell (hMSC) secretome during ex vivo OB differentiation using stable isotope labeling by amino acids in cell culture (SILAC). In addition, we employed pulsed SILAC labeling to distinguish genuine secreted proteins from intracellular contaminants. We identified 466 potentially secreted proteins that were quantified at 5 time-points during 14-days ex vivo OB differentiation including 41 proteins known to be involved in OB functions. Among these, 315 proteins exhibited more than 2-fold up or down-regulation. The pulsed SILAC method revealed a strong correlation between the fraction of isotope labeling and the subset of proteins known to be secreted and involved in OB differentiation. We verified SILAC data using qRT-PCR analysis of 9 identified potential novel regulators of OB differentiation. Furthermore, we studied the biological effects of one of these proteins, the hormone stanniocalcin 2 (STC2) and demonstrated its autocrine effects in enhancing osteoblastic differentiation of hMSC. In conclusion, combining complete and pulsed SILAC labeling facilitated the identification of novel factors produced by hMSC with potential role in OB differentiation. Our study demonstrates that the secretome of osteoblastic cells is more complex than previously reported and supports the emerging evidence that osteoblastic cells secrete proteins with endocrine functions and regulate cellular processes beyond bone formation.
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Affiliation(s)
- Lars P Kristensen
- Center for Experimental Bioinformatics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense
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19
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Kawai M, Breggia AC, DeMambro VE, Shen X, Canalis E, Bouxsein ML, Beamer WG, Clemmons DR, Rosen CJ. The heparin-binding domain of IGFBP-2 has insulin-like growth factor binding-independent biologic activity in the growing skeleton. J Biol Chem 2011; 286:14670-80. [PMID: 21372140 DOI: 10.1074/jbc.m110.193334] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin-like growth factor-binding protein 2 (IGFBP-2) is a member of a family of six highly conserved IGFBPs that are carriers for the insulin-like growth factors (IGFs). IGFBP-2 levels rise during rapid neonatal growth and at the time of peak bone acquisition. In contrast, Igfbp2(-/-) mice have low bone mass accompanied by reduced osteoblast numbers, low bone formation rates, and increased PTEN expression. In the current study, we postulated that IGFBP-2 increased bone mass partly through the activity of its heparin-binding domain (HBD). We synthesized a HBD peptide specific for IGFBP-2 and demonstrated in vitro that it rescued the mineralization phenotype of Igfbp2(-/-) bone marrow stromal cells and calvarial osteoblasts. Consistent with its cellular actions, the HBD peptide ex vivo stimulated metacarpal periosteal expansion. Furthermore, administration of HBD peptide to Igfbp2(-/-) mice increased osteoblast number, suppressed marrow adipogenesis, restored trabecular bone mass, and reduced bone resorption. Skeletal rescue in the Igfbp2(-/-) mice was characterized by reduced PTEN expression followed by enhanced Akt phosphorylation in response to IGF-I and increased β-catenin signaling through two mechanisms: 1) stimulation of its cytosolic accumulation and 2) increased phosphorylation of serine 552. We conclude that the HBD peptide of IGFBP-2 has anabolic activity by activating IGF-I/Akt and β-catenin signaling pathways. These data support a growing body of evidence that IGFBP-2 is not just a transport protein but rather that it functions coordinately with IGF-I to stimulate growth and skeletal acquisition.
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Affiliation(s)
- Masanobu Kawai
- Center for Clinical and Translational Research, Maine Medical Center Research Institute, Scarborough, Maine 04074, USA
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Hamidouche Z, Fromigué O, Ringe J, Häupl T, Marie PJ. Crosstalks between integrin alpha 5 and IGF2/IGFBP2 signalling trigger human bone marrow-derived mesenchymal stromal osteogenic differentiation. BMC Cell Biol 2010; 11:44. [PMID: 20573191 PMCID: PMC2901205 DOI: 10.1186/1471-2121-11-44] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Accepted: 06/23/2010] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The potential of mesenchymal stromal cells (MSCs) to differentiate into functional bone forming cells provides an important tool for bone regeneration. The identification of factors that trigger osteoblast differentiation in MSCs is therefore critical to promote the osteogenic potential of human MSCs. In this study, we used microarray analysis to identify signalling molecules that promote osteogenic differentiation in human bone marrow stroma derived MSCs. RESULTS Microarray analysis and validation experiments showed that the expression of IGF2 and IGFBP2 was increased together with integrin alpha5 (ITGA5) during dexamethasone-induced osteoblast differentiation in human MSCs. This effect was functional since we found that IGF2 and IGFBP2 enhanced the expression of osteoblast phenotypic markers and in vitro osteogenic capacity of hMSCs. Interestingly, we showed that downregulation of endogenous ITGA5 using specific shRNA decreased IGF2 and IGFBP2 expression in hMSCs. Conversely, ITGA5 overexpression upregulated IGF2 and IGFBP2 expression in hMSCs, which indicates tight crosstalks between these molecules. Consistent with this concept, activation of endogenous ITGA5 using a specific antibody that primes the integrin, or a peptide that specifically activates ITGA5 increased IGF2 and IGFBP2 expression in hMSCs. Finally, we showed that pharmacological inhibition of FAK/ERK1/2-MAPKs or PI3K signalling pathways that are enhanced by ITGA5 activation, blunted IGF2 and IGFBP2 expression in hMSCs. CONCLUSION The results show that ITGA5 is a key mediator of IGF2 and IGFBP2 expression that promotes osteoblast differentiation in human MSCs, and reveal that crosstalks between ITGA5 and IGF2/IGFBP2 signalling are important mechanisms that trigger osteogenic differentiation in human bone marrow derived mesenchymal stromal cells.
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Affiliation(s)
- Zahia Hamidouche
- Laboratory of Osteoblast Biology and Pathology, INSERM U606, Paris F-75475, France
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Tran GT, Pagkalos J, Tsiridis E, Narvani AA, Heliotis M, Mantalaris A, Tsiridis E. Growth hormone: does it have a therapeutic role in fracture healing? Expert Opin Investig Drugs 2010; 18:887-911. [PMID: 19480608 DOI: 10.1517/13543780902893069] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND The role of growth hormone (GH) in augmenting fracture healing has been postulated for over half a century. GH has been shown to play a role in bone metabolism and this can be mediated directly or indirectly through IGF-I. OBJECTIVES The use of GH was evaluated as a possible therapeutic agent in augmenting fracture healing. METHOD A literature search was undertaken on GH and its effect on bone fracture healing primarily using MEDLINE/OVID (1950 to January 2009). Key words and phrases including 'growth hormone', 'insulin like growth factor', 'insulin like growth factor binding protein', 'insulin like growth factor receptor', 'fracture repair', 'bone healing', 'bone fracture', 'bone metabolism', 'osteoblast' and 'osteoclast' were used in different combinations. Manual searches of the bibliography of key papers were also undertaken. RESULTS Current evidence suggests a positive role of GH on fracture healing as demonstrated by in vitro studies on osteoblasts, osteoclasts and the crosstalk between the two. Animal studies have demonstrated a number of factors influencing the effect of GH in vivo such as dose, timing and method of administration. Application of this knowledge in humans is limited but clearly demonstrates a positive effect on fracture healing. Concern has been raised in the past regarding the safety profile of the pharmacological use of GH when used in critically ill patients. CONCLUSION The optimal dose and method of administration is still to be determined, and the safety profile of this novel use of GH needs to be investigated prior to establishing its widespread use as a fracture-healing agent.
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Affiliation(s)
- Gui Tong Tran
- University of Leeds School of Medicine, Academic Department of Trauma and Orthopaedics, Leeds General Infirmary, Great George Street, Leeds, UK
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22
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Diehl D, Hessel E, Oesterle D, Renner-Müller I, Elmlinger M, Langhammer M, Göttlicher M, Wolf E, Lahm H, Hoeflich A. IGFBP-2 overexpression reduces the appearance of dysplastic aberrant crypt foci and inhibits growth of adenomas in chemically induced colorectal carcinogenesis. Int J Cancer 2009; 124:2220-5. [PMID: 19142966 DOI: 10.1002/ijc.24193] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Colon cancer patients frequently show increased levels of serum insulin-like growth factor-binding protein-2 (IGFBP-2), however, the pathogenetic relevance of this phenomenon for colorectal cancer is unclear. Therefore, we have used IGFBP-2 transgenic animals which overexpress IGFBP-2 systemically and locally in the intestine to study its role in chemically induced colorectal carcinogenesis. Mice received intraperitoneal injections of 1,2-dimethylhydrazine (DMH) (40 mg/kg body weight) once a week for 6 weeks to selectively induce aberrant crypt foci (ACF) and tumors in the colon. While tumor incidence was comparable in transgenic and control mice, the volume of adenomas in IGFBP-2 transgenic mice was reduced more than 2-fold. Furthermore, serum IGFBP-2 levels negatively correlated with tumor volume in the IGFBP-2 transgenic group. Histological examination showed that IGFBP-2 transgenic mice developed significantly less dysplastic ACF with a high potential to progress to advanced stages. The reduced tumor volume in IGFBP-2 transgenic animals was due to significantly reduced proliferative capacity, evidenced by a lower proportion of cells positive for Ki67. Our results demonstrate for the first time in an experimental model that IGFBP-2 overabundance prior to the onset and during colorectal carcinogenesis reduces tumor growth by inhibition of cell proliferation.
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Affiliation(s)
- Daniela Diehl
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, LMU Munich, Munich, Germany
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23
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Rorive S, Berton A, D'haene N, Takacs CN, Debeir O, Decaestecker C, Salmon I. Matrix metalloproteinase-9 interplays with the IGFBP2-IGFII complex to promote cell growth and motility in astrocytomas. Glia 2009; 56:1679-90. [PMID: 18563800 DOI: 10.1002/glia.20719] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Insulin-like growth factor II (IGFII) acts as a potent mitogen for several tumor types and has been reported to positively influence astrocytoma cell growth and motility. In the central nervous system, IGFII bioavailability is mainly modulated by insulin-like growth factor binding protein 2 (IGFBP2), which sequestrates IGFII and therefore prevents its interaction with the type-1 IGF receptor (IGF-IR). Proteolysis of IGFBP2 is the predominant mechanism recognized to reduce the binding affinity of IGFBP2 for IGFII, thus favoring dissociation of IGFII from the IGFBP2-IGFII complex. It is known that certain proteases involved in astrocytoma malignancy, such as matrix metalloproteinase-7 (MMP-7), plasmin, and cathepsin D, are able to proteolyze IGFBP2 in vitro. The present study aims to investigate whether other proteases expressed by astrocytomas, specifically MMP-2, MMP-9, and membrane-type 1 matrix metalloprotease (MT1-MMP), are able to proteolyze the IGFBP2-IGFII complex. Our results show the following: (i) MMP-9 proteolyzes the IGFBP2-IGFII complex in vitro, while MMP-2 and MT1-MMP do not; (ii) this MMP-9-induced IGFBP2-IGFII complex proteolysis releases free IGFII, which contributes to enhance the motility and the growth of LN229 astrocytoma cells. Furthermore, this study also highlights that the formation of the IGFBP2-IGFII complex inhibits IGFBP2's cell motility promoting effect by reducing the pool of free IGFBP2. In conclusion, MMP-9-induced IGFBP2 proteolysis may be regarded as an important post-translational event involved in astrocytoma aggressiveness. These new findings support drug targeting of MMP-9 as an interesting approach in the treatment of astrocytoma.
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Affiliation(s)
- Sandrine Rorive
- Department of Pathology, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
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24
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Manduca P, Castagnino A, Lombardini D, Marchisio S, Soldano S, Ulivi V, Zanotti S, Garbi C, Ferrari N, Palmieri D. Role of MT1-MMP in the osteogenic differentiation. Bone 2009; 44:251-65. [PMID: 19027888 DOI: 10.1016/j.bone.2008.10.046] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2008] [Revised: 09/27/2008] [Accepted: 10/16/2008] [Indexed: 11/16/2022]
Abstract
Metalloproteinase MT1-MMP is induced and Pro-MMP-2 up modulated early in rat preosteoblasts (ROB) set to differentiate. We here show that the induction of MMPs, accompanied by activation of Pro-MMP-2, occurs by 6 h of adhesion on endogenous extracellular matrix (ECM), Fibronectin (FN) and Collagen type I (CI). These events do not occur after adhesion on Collagen III (CIII), Vitronectin (VN) or BSA. Within the first hour on inducing substrata or plastic, FAK is unchanged and ERK(1,2), is activated, but this activation is not sufficient for MT1-MMP induction. The function of p38 MAPK and PTKs is not required for the induction by substrata of MMPs. Six hours after plating preosteoblasts on MMP-inducing substrata, complexes of beta1 integrin with MT1-MMP are formed, that contain integrin dimers specifically engaged by the substratum, alpha4 and alpha5 chains for cells plated on FN, and alpha2 chain for cells plated on CI and ECM. Induction of MT1-MMP and its expression during osteogenesis pleiotropically regulate alkaline phosphatase (AP) expression. During differentiation, variant clones derived from preosteoblasts and MMPs-over-expressing osteoblasts show high MT1-MMP level associated with high AP level both persisting in time, while inhibition of MMPs is accompanied by inhibition of AP. Up or down modulation of AP, transcriptionally or by inhibition of the enzyme activity, has no effect on level or timing of expression of MT1-MMP and Pro-MMP-2. The persistence in expression of MT1-MMP during differentiation, and the associated persistence in expression of AP, as well as their inhibition, both impair the formation of nodules and mineral deposition. A transient pattern of expression of MT1-MMP is required for the establishment of nodules, and MT1-MMP decrease is permissive for nodule mineralization. The expression of AP is required for nodule formation and its level modulates the mineralization. MT1-MMP has multiple functions and is implicated in multiple steps of the differentiation process, acting to regulate homeostasis of the osteogenic differentiation.
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Affiliation(s)
- Paola Manduca
- Genetics, DiBio, University of Genoa, 26, C. Europa, Genoa 16132, Italy.
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25
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Aonuma H, Ogura N, Kamino Y, Ito K, Kondoh T. Microarray Analysis of Human Dental Follicle Cells in Osteogenic Differentiation. J HARD TISSUE BIOL 2009. [DOI: 10.2485/jhtb.18.27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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26
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Zou X, Zou L, Foldager C, Bendtsen M, Feng W, Bünger CE. Different mechanisms of spinal fusion using equine bone protein extract, rhBMP-2 and autograft during the process of anterior lumbar interbody fusion. Biomaterials 2008; 30:991-1004. [PMID: 19046765 DOI: 10.1016/j.biomaterials.2008.10.061] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2008] [Accepted: 10/27/2008] [Indexed: 10/21/2022]
Abstract
To elucidate the molecular mechanisms of spinal fusion with different graft materials during an anterior lumbar interbody fusion, we examined the gene-expression profiles after implantation of equine bone protein extract, rhBMP-2 and autograft using microarray technology and data analysis, including hierarchical clustering, self-organizing maps (SOM), KEGG pathway and Biological process GO analyses in a porcine model. The results suggest that equine bone protein extract exhibited a more similar expression pattern with autograft than that of rhBMP-2. rhBMP-2 recruits progenitor cells, proliferation and differentiation possibly by inducing various factors including PGHS-2, IFGBP-2, VEGF and chemokines and then leads to preferable membranous ossification and bone remodeling. Conversely, equine bone protein extract results in endochondral ossification via upregulation of cartilage-related genes. Ossification by inducing direct osteoblastic differentiation and obviating the cartilaginous intermediate phases may increase spinal fusion rate.
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Affiliation(s)
- Xuenong Zou
- Department of Spine, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
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27
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Grundberg E, Brändström H, Lam KCL, Gurd S, Ge B, Harmsen E, Kindmark A, Ljunggren O, Mallmin H, Nilsson O, Pastinen T. Systematic assessment of the human osteoblast transcriptome in resting and induced primary cells. Physiol Genomics 2008; 33:301-11. [PMID: 18334548 DOI: 10.1152/physiolgenomics.00028.2008] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Osteoblasts are key players in bone remodeling. The accessibility of human primary osteoblast-like cells (HObs) from bone explants makes them a lucrative model for studying molecular physiology of bone turnover, for discovering novel anabolic therapeutics, and for mesenchymal cell biology in general. Relatively little is known about resting and dynamic expression profiles of HObs, and to date no studies have been conducted to systematically assess the osteoblast transcriptome. The aim of this study was to characterize HObs and investigate signaling cascades and gene networks with genomewide expression profiling in resting and bone morphogenic protein (BMP)-2- and dexamethasone-induced cells. In addition, we compared HOb gene expression with publicly available samples from the Gene Expression Omnibus. Our data show a vast number of genes and networks expressed predominantly in HObs compared with closely related cells such as fibroblasts or chondrocytes. For instance, genes in the insulin-like growth factor (IGF) signaling pathway were enriched in HObs (P = 0.003) and included the binding proteins (IGFBP-1, -2, -5) and IGF-II and its receptor. Another HOb-specific expression pattern included leptin and its receptor (P < 10(-8)). Furthermore, after stimulation of HObs with BMP-2 or dexamethasone, the expression of several interesting genes and pathways was observed. For instance, our data support the role of peripheral leptin signaling in bone cell function. In conclusion, we provide the landscape of tissue-specific and dynamic gene expression in HObs. This resource will allow utilization of osteoblasts as a model to study specific gene networks and gene families related to human bone physiology and diseases.
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Affiliation(s)
- Elin Grundberg
- McGill University and Genome Quebec Innovation Centre, Montreal, Canada
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28
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Abstract
Insulin-like growth factor-binding proteins (IGFBPs) are important regulators of bone metabolism. However, their precise roles are not fully understood, since IGFBPs can have both enhancing and inhibiting effects on IGF action, depending on context and posttranslational modifications, as well as IGF-independent effects. This review focuses on recent findings from cell culture, rodent models, and clinical studies concerning local IGFBP-2, IGFBP-4, and IGFBP-5 action in bone.
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Affiliation(s)
- Cheryl A Conover
- Endocrine Research Unit, Division of Endocrinology and Metabolosm, Department of Medicine, Mayo Clinic, 200 First St. SW, 5-194 Joseph, Rochester, MN 55905, USA.
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29
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Amin S, Riggs BL, Melton LJ, Achenbach SJ, Atkinson EJ, Khosla S. High serum IGFBP-2 is predictive of increased bone turnover in aging men and women. J Bone Miner Res 2007; 22:799-807. [PMID: 17352648 DOI: 10.1359/jbmr.070306] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED Elevated serum IGFBP-2 is associated with lower BMD in men and women. It is unknown whether IGFBP-2 serves as a negative regulator of bone metabolism by decreasing bone formation or increasing bone resorption. Studying an age-stratified community-based sample of 344 men and 276 women, IGFBP-2 was the strongest predictor of increased bone resorption among the IGF/IGFBPs studied. INTRODUCTION Serum insulin-like growth factor binding protein-2 (IGFBP-2), which increases with age, is a predictor of low BMD among aging men and women. However, it is unknown whether IGFBP-2 negatively influences bone metabolism by decreasing bone formation or increasing bone resorption. Few have examined the relation between the insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) with bone turnover markers. MATERIALS AND METHODS In an age-stratified, random sample of the community, we examined the association between serum IGF-I, IGF-II, IGFBP-1, -2, and -3, and bone turnover markers before and after adjustment for potential confounders (age, body mass index, bioavailable estradiol and testosterone, and sex hormone binding globulin). Analyses were stratified by sex and menopausal status. RESULTS We studied 344 men (age range, 23-90 yr) and 276 women (age range, 21-93 yr; 166 postmenopausal) not on oral contraceptives or hormone replacement. Among the IGF/IGFBPs assessed, IGFBP-2 was the strongest and most consistent predictor of bone turnover in men and women. After adjustment for potential confounders, IGFBP-2 was positively associated with osteocalcin (OC) and urine and serum N-teleopeptide (NTX) in men (r = 0.20, 0.26, and 0.23, respectively; p < 0.001), serum C-telopeptide (CTX) in premenopausal women (r = 0.28; p < 0.01), and OC, urine NTX, and serum CTX in postmenopausal women (r = 0.24, 0.33, and 0.19, respectively; p < 0.05). CONCLUSIONS Higher serum IGFBP-2, which is predictive of lower BMD, is associated with increased markers of bone resorption, independent of age, body mass, and sex hormones. The association between IGFBP-2 and markers of bone formation may reflect coupling with increased bone resorption, which is not adequate to maintain BMD.
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Affiliation(s)
- Shreyasee Amin
- Division of Rheumatology, Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
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30
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Reijnders CMA, Bravenboer N, Holzmann PJ, Bhoelan F, Blankenstein MA, Lips P. In vivo mechanical loading modulates insulin-like growth factor binding protein-2 gene expression in rat osteocytes. Calcif Tissue Int 2007; 80:137-43. [PMID: 17308996 PMCID: PMC1914289 DOI: 10.1007/s00223-006-0077-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2006] [Accepted: 10/20/2006] [Indexed: 11/05/2022]
Abstract
Mechanical stimulation is essential for maintaining skeletal integrity. Mechanosensitive osteocytes are important during the osteogenic response. The growth hormone-insulin-like growth factor (GH-IGF) axis plays a key role during regulation of bone formation and remodeling. Insulin-like growth factor binding proteins (IGFBPs) are able to modulate IGF activity. The aim of this study was to characterize the role of IGFBP-2 in the translation of mechanical stimuli into bone formation locally in rat tibiae. Female Wistar rats were assigned to three groups (n = 5): load, sham, and control. The four-point bending model was used to induce a single period of mechanical loading on the tibial shaft. The effect on IGFBP-2 mRNA expression 6 hours after stimulation was determined with nonradioactive in situ hybridization on decalcified tibial sections. Endogenous IGFBP-2 mRNA was expressed in trabecular and cortical osteoblasts, some trabecular and subendocortical osteocytes, intracortical endothelial cells of blood vessels, and periosteum. Megakaryocytes, macrophages, and myeloid cells also expressed IGFBP-2 mRNA. Loading and sham loading did not affect IGFBP-2 mRNA expression in osteoblasts, bone marrow cells, and chondrocytes. An increase of IGFBP-2 mRNA-positive osteocytes was shown in loaded (1.68-fold) and sham-loaded (1.35-fold) endocortical tibial shaft. In conclusion, 6 hours after a single loading session, the number of IGFBP-2 mRNA-expressing osteocytes at the endosteal side of the shaft and inner lamellae was increased in squeezed and bended tibiae. Mechanical stimulation modulates IGFBP-2 mRNA expression in endocortical osteocytes. We suggest that IGFBP-2 plays a role in the lamellar bone formation process.
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Affiliation(s)
- C. M. A. Reijnders
- Department of Endocrinology, Vrye Universiteit University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
| | - N. Bravenboer
- Department of Endocrinology, Vrye Universiteit University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
- Department of Clinical Chemistry, Vrye Universiteit University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
| | - P. J. Holzmann
- Department of Endocrinology, Vrye Universiteit University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
| | - F. Bhoelan
- Department of Endocrinology, Vrye Universiteit University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
| | - M. A. Blankenstein
- Department of Clinical Chemistry, Vrye Universiteit University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
| | - P. Lips
- Department of Endocrinology, Vrye Universiteit University Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands
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31
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Fisher MC, Meyer C, Garber G, Dealy CN. Role of IGFBP2, IGF-I and IGF-II in regulating long bone growth. Bone 2005; 37:741-50. [PMID: 16183342 DOI: 10.1016/j.bone.2005.07.024] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2005] [Revised: 04/20/2005] [Accepted: 07/05/2005] [Indexed: 01/15/2023]
Abstract
The IGF axis is important for long bone development, homeostasis and disease. The activities of IGF-I and IGF-II are regulated by IGF binding proteins (IGFBPs). IGF-I and IGFBP2 are co-expressed in dynamic fashions in the developing long bones of the chick wing, and we have found that IGF-II is present in the cartilage model and surrounding perichondrium, proliferative and hypertrophic chondrocytes and developing periosteum. To gain insight into endogenous roles of IGF-I, IGF-II and IGFBP2 in long bone development, we have overexpressed IGFBP2 in the developing skeletal elements of the embryonic chick wing in vivo, using an RCAS retroviral vector. IGFBP2 overexpression led to an obvious shortening of the long bones of the wing. We have investigated, at the cellular and molecular levels, the mechanism of action whereby IGFBP2 overexpression impairs long bone development in vivo. At an early stage, IGFBP2 excess dramatically inhibits proliferation by the chondrocytes of the cartilage models that prefigure the developing long bones. Later, IGFBP2 excess also reduces proliferation of the maturing chondrocytes and attenuates proliferation by the perichondrium/developing periosteum. IGFBP2 excess does not affect morphological or molecular indicators of chondrocyte maturation, osteoblast differentiation or cell/matrix turnover, such as expression of Ihh, PTHrP, type X collagen and osteopontin, or distribution and relative abundance of putative clast cells. We also have found that IGFBP2 blocks the ability of IGF-I and IGF-II to promote proliferation and matrix synthesis by wing chondrocytes in vitro. Together, our results suggest that the mechanism of action whereby IGFBP2 excess impairs long bone development is to inhibit IGF-mediated proliferation and matrix synthesis by the cartilage model; reduce the proliferation and progression to hypertrophy by the maturing chondrocytes; and attenuate proliferation and formation of the periosteal bony collar. These actions retard the growth and longitudinal expansion of the developing long bones, resulting in shortened wing skeletal elements. Our results emphasize the importance of a balance of IGF/IGFBP2 action at several stages during normal long bone development.
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Affiliation(s)
- Melanie C Fisher
- Center for Limb and Skeletal Development, Department of BioStructure and Function, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA
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Ferone D, Arvigo M, Semino C, Jaquet P, Saveanu A, Taylor JE, Moreau JP, Culler MD, Albertelli M, Minuto F, Barreca A. Somatostatin and dopamine receptor expression in lung carcinoma cells and effects of chimeric somatostatin-dopamine molecules on cell proliferation. Am J Physiol Endocrinol Metab 2005; 289:E1044-50. [PMID: 16046458 DOI: 10.1152/ajpendo.00209.2005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To study somatostatin/dopamine (SS/D) synergy in a human cell system constitutively expressing SS and D receptors (SSR and DR, respectively), we characterized the expression of SSR and DR subtypes in the non-small-cell lung cancer line Calu-6, and then we evaluated the effect on cell proliferation of SS/D chimeric molecules (BIM-23A387 and BIM-23A370), which bind with high affinity both sst(2) and D(2)R, and compared the results with those obtained by using SS-14 and subtype-selective SS analogs (SSA) and D agonists (DA). Because Calu-6 cells produce insulin-like growth factor (IGF) and IGF-binding protein (IGFBP) peptides, which play a role in the autocrine/paracrine control of cell growth, we also investigated the effects of chimeric compounds on secretion and expression of IGF system components. Relative high levels of sst(2) and the long isoform of the D(2)R were detected by real-time RT-PCR and Western blot in Calu-6, together with sst(5) and to a lesser extent sst(3) and D(4)R. BIM-23A387 and BIM-23A370 significantly inhibited growth of Calu-6, whereas IGF-IGFBP secretion or expression was unaffected, suggesting a direct inhibitory effect. The inhibition of cell growth, measured by both [(3)H]thymidine incorporation and cell count, was significantly lower when individual SSA and DA control peptides or subtype-specific SSA and DA were tested. BIM-23A370 was more potent than BIM-23A387 (P < 0.001). These findings show that SS/D chimeras can inhibit Calu-6 proliferation in an IGF-independent manner and suggest that this enhanced potency might be because of the induction of SSR/DR dimerization. The Calu-6 cell line, constitutively expressing SSR and DR, provides a suitable model to elucidate the mechanism of action of SSA and DA on regulation of cell growth and to characterize the interaction between SSR and DR.
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Affiliation(s)
- Diego Ferone
- Dept. of Endocrinological & Metabolic Sciences, University of Genoa, Viale Benedetto XV 6, 16132-Genoa, Italy.
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33
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Le AD, Basi DL, Abubaker AO. Wound healing: findings of the 2005 AAOMS Research Summit. J Oral Maxillofac Surg 2005; 63:1426-35. [PMID: 16182909 DOI: 10.1016/j.joms.2005.07.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Indexed: 11/20/2022]
Affiliation(s)
- Anh D Le
- Division of Surgical, Therapeutics, and Bioengineering Sciences, Center for Craniofacial Molecular Biology, University of Southern California, School of Dentistry, Los Angeles, CA 90089, USA.
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Shibata Y, Tsukazaki T, Hirata K, Xin C, Yamaguchi A. Role of a new member of IGFBP superfamily, IGFBP-rP10, in proliferation and differentiation of osteoblastic cells. Biochem Biophys Res Commun 2004; 325:1194-200. [PMID: 15555553 DOI: 10.1016/j.bbrc.2004.10.157] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2004] [Indexed: 11/29/2022]
Abstract
Bone regeneration is critically regulated by various molecules. To identify the new genes involved in bone regeneration, we performed microarray-based gene expression analysis using a mouse bone regeneration model. We identified a new member of the IGFBP superfamily, designated IGFBP-rP10, whose expression is up-regulated at the early phase of bone regeneration. IGFBP-rP10 consists of an IGFBP homologous domain followed by a Kazal-type protein inhibitor domain and an immunoglobulin G-like domain. A real-time-based RT-PCR analysis demonstrated that various tissues including bone expressed IGFBP-rP10 mRNA in various degrees, and confirmed an up-regulation at the early phase of bone regeneration. In situ hybridization revealed that osteoblastic cells expressed IGFPB-rP10 mRNA during bone regeneration. Bone morphogenetic protein-2 increased the expression level of IGFBP-rP10 mRNA in various cells including C3H10T1/2, MC3T3-E1, C2C12, and primary murine osteoblastic cells. The addition of recombinant mouse IGFBP-rP10 promoted the proliferation of these cells but failed to stimulate alkaline phosphatase activity. These results suggest that IGFBP-rP10 is involved in the proliferation of osteoblasts during bone formation and bone regeneration.
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Affiliation(s)
- Yasuaki Shibata
- Division of Oral Pathology and Bone Metabolism, Department of Developmental and Reconstructive Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8588, Japan
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