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Paracha N, Mastrokostas P, Kello E, Gedailovich Y, Segall D, Rizzo A, Mitelberg L, Hassan N, Dowd TL. Osteocalcin improves glucose tolerance, insulin sensitivity and secretion in older male mice. Bone 2024; 182:117048. [PMID: 38378083 DOI: 10.1016/j.bone.2024.117048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/19/2024] [Accepted: 02/09/2024] [Indexed: 02/22/2024]
Abstract
Osteocalcin deficient mice (OC-/-), on a mixed 129/BL6J background, were reported to show glucose intolerance, insulin insensitivity and reduced insulin secretion at 1-6 mos of age. This is controversial as two studies in OC-/- mice on different backgrounds (C3H/BL6 (5-6 mos.) and C57BL/6N (5 and 9 mos.)) found no effect on glucose metabolism. To determine the role of OC in glucose metabolism we conducted glucose tolerance tests (GTT), insulin tolerances tests (ITT) and glucose stimulated insulin secretion (GSIS) on 6 and 9.5 month-old male OC-/- and OC+/+ mice on a pure C57BL/6J background and fed a normal chow diet. All results were analyzed with a two-way repeated measures ANOVA. The GTT results showed no effect on males at 6 months of age but glucose intolerance was significantly increased (p < 0.05) in male OC-/- mice at 9.5 months of age. The ITT results indicated significantly increased insulin resistance in male OC-/- mice. Glucose stimulated insulin secretion (GSIS) showed insulin significantly (p < 0.05) reduced in OC-/- at several time points. Mouse Osteocalcin injected into OC-/- mice decreased the glucose level. Our results confirm the role of OC in glucose metabolism and insulin sensitivity and demonstrate a role in insulin secretion in older male mice on a C57BL/6J background. Differences in background, age, or experimental procedures could explain controversial results. A delayed onset of the effect of OC on glucose metabolism at 9.5 months in male C57BL/6J mice highlights the importance of background on phenotype. Consideration of genetic background and age may be beneficial for human studies on osteocalcin and glucose homeostasis and may be relevant to the elderly where osteocalcin is reduced.
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Affiliation(s)
- Noorulain Paracha
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Paul Mastrokostas
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Evan Kello
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Yosef Gedailovich
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Devorah Segall
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Alexis Rizzo
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Lawrence Mitelberg
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Naif Hassan
- Department of Biology, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America
| | - Terry Lynne Dowd
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY 11210, United States of America; Ph.D. Program in Chemistry and Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America.
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Yildirim G, Budell W, Berezovska O, Yagerman S, Maliath S, Mastrokostas P, Tommasini S, Dowd T. Lead induced differences in bone properties in osteocalcin +/+ and −/− female mice. Bone Rep 2023; 18:101672. [PMID: 37064000 PMCID: PMC10090701 DOI: 10.1016/j.bonr.2023.101672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 02/25/2023] [Accepted: 03/15/2023] [Indexed: 03/19/2023] Open
Abstract
Lead (Pb) toxicity is a major health problem and bone is the major reservoir. Lead is detrimental to bone, affects bone remodeling and is associated with elderly fractures. Osteocalcin (OC) affects bone remodeling, improves fracture resistance and decreases with age and in some diseases. The effect of lead in osteocalcin depleted bone is unknown and of interest. We compared bone mineral properties of control and Pb exposed (from 2 to 6 months) femora from female adult C57BL6 OC+/+ and OC-/- mice using Fourier Transform Infrared Imaging (FTIRI), Micro-computed tomography (uCT), bone biomechanical measurements and serum turnover markers (P1NP, CTX). Lead significantly increased turnover in OC+/+ and in OC-/- bones producing increased total volume, area and marrow area/total area with decreased BV/TV compared to controls. The increased turnover decreased mineral/matrix vs. Oc+/+ and increased mineral/matrix and crystallinity vs. OC-/-. PbOC-/- had increased bone formation, cross-sectional area (Imin) and decreased collagen maturity compared OC-/- and PbOC+/+. Imbalanced turnover in PbOC-/- confirmed the role of osteocalcin as a coupler of formation and resorption. Bone strength and stiffness were reduced in OC-/- and PbOC-/- due to reduced material properties vs. OC+/+ and PbOC+/+ respectively. The PbOC-/- bones had increased area to compensate for weaker material properties but were not proportionally stronger for increased size. However, at low lead levels osteocalcin plays the major role in bone strength suggesting increased fracture risk in low Pb2+ exposed elderly could be due to reduced osteocalcin as well. Years of low lead exposure or higher blood lead levels may have an additional effect on bone strength.
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Affiliation(s)
- G. Yildirim
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY, USA
| | - W.C. Budell
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY, USA
| | - O. Berezovska
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY, USA
| | - S. Yagerman
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
| | - S.S. Maliath
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY, USA
| | - P. Mastrokostas
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY, USA
| | - S. Tommasini
- Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT, USA
| | - T.L. Dowd
- Department of Chemistry, Brooklyn College of the City University of New York, Brooklyn, NY, USA
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, USA
- Corresponding author at: Department of Chemistry, Rm. 359 NE, Brooklyn College of the City University of New York, 2900 Bedford Ave., Brooklyn, NY 11210, USA.
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3
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Wang H, Li J, Xu Z, Wu F, Zhang H, Yang C, Chen J, Ding B, Sui X, Guo Z, Li Y, Dai Z. Undercarboxylated osteocalcin inhibits the early differentiation of osteoclast mediated by Gprc6a. PeerJ 2021; 9:e10898. [PMID: 33717684 PMCID: PMC7934677 DOI: 10.7717/peerj.10898] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/13/2021] [Indexed: 11/20/2022] Open
Abstract
Osteocalcin (OCN) was the most abundant noncollagen protein and considered as an endocrine factor. However, the functions of Undercarboxylated osteocalcin (ucOCN) on osteoclast and bone resorption are not well understood. In the present study, preosteoclast RAW264.7 cells and bone marrow mononuclear cells (BMMs) were treated with ucOCN purified from prokaryotic bacteria. Our results showed that ucOCN attenuated the proliferation of RAW264.7 cells with a concentration dependant manner by MTS assay. Scrape wounding assay revealed the decreased motility of RAW264.7 cells after ucOCN treatment. RT-qPCR results manifested the inhibitory effects of ucOCN on the expression of osteoclastic marker genes in RAW264.7 cells during inducing differentiation of RANKL. It was also observed that ucOCN inhibited the formation of multinucleated cells from RAW264.7 cells and BMMs detected by TRAP staining. The number and area of bone resorb pits were also decreased after treatment with ucOCN during their osteoclast induction by toluidine blue staining. The formation and integrity of the osteoclast actin ring were impaired by ucOCN by immunofluorescent staining. Time dependant treatment of ucOCN during osteoclastic induction demonstrated the inhibitory effects mainly occurred at the early stage of osteoclastogenesis. Signaling analysis of luciferase activity of the CRE or SRE reporter and ERK1/2 phosphorylation showed the selective inhibitor or siRNA of Gprc6a (a presumptive ucOCN receptor) could attenuate the promotion of ucOCN on CRE-luciferase activity. Taken together, we provided the first evidence that ucOCN had negative effects on the early differentiation and bone resorption of osteoclasts via Gprc6a.
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Affiliation(s)
- Hailong Wang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Jinqiao Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China.,Space Engineering University, Beijing, China
| | - Zihan Xu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Feng Wu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Hongyu Zhang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Chao Yang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Jian Chen
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China.,Department of Orthopaedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Bai Ding
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Xiukun Sui
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Zhifeng Guo
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Yinghui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Zhongquan Dai
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
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Berezovska O, Yildirim G, Budell WC, Yagerman S, Pidhaynyy B, Bastien C, van der Meulen MCH, Dowd TL. Osteocalcin affects bone mineral and mechanical properties in female mice. Bone 2019; 128:115031. [PMID: 31401301 PMCID: PMC8243730 DOI: 10.1016/j.bone.2019.08.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 07/23/2019] [Accepted: 08/05/2019] [Indexed: 12/13/2022]
Abstract
Osteocalcin is one of the most abundant noncollagenous proteins in bone. Phenotypes of osteocalcin knock-out mice (OC-/-) may vary on different backgrounds and with sex. Previous studies using adult female (OC-/-) mice on a mixed genetic background (129/B6) showed osteocalcin inhibited bone formation leading to weaker bone in wild-type (OC+/+). Yet on a pure (B6) genetic background male mice revealed osteocalcin improved fracture resistance and OC-/- bones were more prone to fracture. Osteocalcin is decreased with age and in some diseases (diabetes) where bone weakness is observed. The effect of osteocalcin in adult female bone from mice on a pure B6 background is unknown. We investigated differences in bone mineral properties and bone strength in female adult (6 months) (OC+/+) and (OC-/-) mice on a pure C57BL/6J background using Fourier Transform Infrared Imaging (FTIRI), micro-computed tomography (uCT), biomechanical measurements, histomorphometry and serum turnover markers (P1NP, CTX). Similar to female age matched mice on the (129/C57) background we found B6 OC-/- mice had a higher bone formation rate, no change in bone resorption, more immature mineral, decreased crystallinity and increased trabecular bone as compared to OC+/+. In contrast, the OC-/- mice on a pure B6 background had a lower bone mineral density, lower mineral to matrix ratio resulting in reduced stiffness and weaker bone strength. Our results demonstrate some properties of the OC-/- phenotype are dependent on genetic background. This may suggest that reduced osteocalcin may contribute to fracture and weaker bone in some groups of elderly and adults with diseases where osteocalcin is low.
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Affiliation(s)
- O Berezovska
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210, United States of America
| | - G Yildirim
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210, United States of America
| | - W C Budell
- Department of Biology, Brooklyn College, Brooklyn, NY 11210, United States of America
| | - S Yagerman
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America; Sibley School of Mechanical & Aerospace Engineering, Cornell University, Ithaca, NY, United States of America
| | - B Pidhaynyy
- Department of Biology, Brooklyn College, Brooklyn, NY 11210, United States of America
| | - C Bastien
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210, United States of America
| | - M C H van der Meulen
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States of America; Research Division, Hospital for Special Surgery, NY, NY, United States of America; Sibley School of Mechanical & Aerospace Engineering, Cornell University, Ithaca, NY, United States of America
| | - T L Dowd
- Department of Chemistry, Brooklyn College, Brooklyn, NY 11210, United States of America; Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America; Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY 10016, United States of America.
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5
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Li J, Zhang H, Yang C, Li Y, Dai Z. An overview of osteocalcin progress. J Bone Miner Metab 2016; 34:367-79. [PMID: 26747614 DOI: 10.1007/s00774-015-0734-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/22/2015] [Indexed: 12/20/2022]
Abstract
An increasing amount of data indicate that osteocalcin is an endocrine hormone which regulates energy metabolism, male fertility and brain development. However, the detailed functions and mechanism of osteocalcin are not well understood and conflicting results have been obtained from researchers worldwide. In the present review, we summarize the progress of osteocalcin studies over the past 40 years, focusing on the structure of carboxylated and undercarboxylated osteocalcin, new functions and putative receptors, the role of osteocalcin in bone remodeling, specific expression and regulation in osteoblasts, and new indices for clinical studies. The complexity of osteocalcin in completely, uncompletely and non-carboxylated forms may account for the discrepancies in its tertiary structure and clinical results. Moreover, the extensive expression of osteocalcin and its putative receptor GPRC6A imply that there are new physiological functions and mechanisms of action of osteocalcin to be explored. New discoveries related to osteocalcin function will assist its potential clinical application and physiological theory, but comprehensive investigations are required.
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Affiliation(s)
- Jinqiao Li
- China Astronaut Research and Training Center, State Key Lab of Space Medicine Fundamentals and Application, P.O.Box 1053-23#, No. 26, Beijing Road, Haidian District, Beijing, 100094, China
| | - Hongyu Zhang
- China Astronaut Research and Training Center, State Key Lab of Space Medicine Fundamentals and Application, P.O.Box 1053-23#, No. 26, Beijing Road, Haidian District, Beijing, 100094, China
| | - Chao Yang
- China Astronaut Research and Training Center, State Key Lab of Space Medicine Fundamentals and Application, P.O.Box 1053-23#, No. 26, Beijing Road, Haidian District, Beijing, 100094, China
| | - Yinghui Li
- China Astronaut Research and Training Center, State Key Lab of Space Medicine Fundamentals and Application, P.O.Box 1053-23#, No. 26, Beijing Road, Haidian District, Beijing, 100094, China
| | - Zhongquan Dai
- China Astronaut Research and Training Center, State Key Lab of Space Medicine Fundamentals and Application, P.O.Box 1053-23#, No. 26, Beijing Road, Haidian District, Beijing, 100094, China.
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6
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Nagai H, Kobayashi-Fujioka M, Fujisawa K, Ohe G, Takamaru N, Hara K, Uchida D, Tamatani T, Ishikawa K, Miyamoto Y. Effects of low crystalline carbonate apatite on proliferation and osteoblastic differentiation of human bone marrow cells. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2015; 26:99. [PMID: 25655499 DOI: 10.1007/s10856-015-5431-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 12/09/2014] [Indexed: 06/04/2023]
Abstract
Carbonated apatite (CO3Ap) is the inorganic component of bone. We have proposed a new method for the fabrication of CO3Ap blocks based on a dissolution-precipitation method using a synthetic precursor. The aim of this study is to examine the effects of low crystalline CO3Ap on initial cell attachment, proliferation and osteoblastic differentiation of human bone marrow cells (hBMCs) using sintered hydroxyapatite and tissue culture plates as controls. Initial cell attachment and proliferation were assessed with a MTT assay. Expression of osteoblastic markers was examined by reverse transcription-polymerase chain reaction. XRD and FT-IR results showed formation of B-type carbonate apatite with lower crystallinity. No difference was observed for initial cell attachment between HAp and CO3Ap discs. hBMSC attached more significantly on tissue culture plate than on HAp and CO3Ap discs. The number of cells on HAp was higher than that on CO3Ap until day 7, after which the number of cells was similar. hBMSC proliferated more significantly on tissue culture plate than on HAp and CO3Ap discs. In contrast, hBMCs incubated on CO3Ap demonstrated much higher expression of osteoblastic markers of differentiation, such as type I collagen, alkaline phosphatase, osteopontin and osteocalcin, than hBMCs on HAp. On the tissue culture plate, they were not any change throughout the culture period. These results demonstrated that low crystalline CO3Ap exhibit higher osteoinductivity than HAp.
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Affiliation(s)
- Hirokazu Nagai
- Subdivision of Molecular Oral Medicine, Division of Integrated Sciences of Translational Research, Department of Oral Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15 Kuramoto-cho, Tokushima, 770-8504, Japan,
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Prolonged Diuretic Activity and Calcium-Sparing Effect of Tropaeolum majus: Evidence in the Prevention of Osteoporosis. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:958291. [PMID: 25028592 PMCID: PMC4083603 DOI: 10.1155/2014/958291] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 05/27/2014] [Indexed: 01/13/2023]
Abstract
Although several studies indicate high effectiveness in the use of the hydroethanolic extract from Tropaeolum majus (HETM) as a diuretic, the impact of its prolonged use in the presence of low estrogen levels remains unclear. Thus, the aim of this study was to investigate the diuretic effects of prolonged administration of HETM in ovariectomized rats and their interrelationship between calcium excretion and bone turnover. Forty-two female Wistar rats were ovariectomized (OVX) and treated orally with different doses of HETM (3, 30, and 300 mg/kg) for 4 weeks. On the first day of treatment and at weekly intervals for four weeks the diuretic activity was evaluated. Electrolyte concentrations and creatinine levels were estimated from urine sample of each rat. The serum lipids, urea, creatinine, and osteocalcin were also measured at the end of the experiment. The data revealed that the HETM was able to sustain its diuretic effect after prolonged treatment. Moreover, its use has not affected the urinary calcium or potassium excretion, reduces lipid levels, and maintains osteocalcin levels similarly to untreated rats. These findings support the potential of HETM as a candidate to be used in clinical conditions in which the renal loss of calcium is not desired.
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8
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Vester H, Holzer N, Neumaier M, Lilianna S, Nüssler AK, Seeliger C. Green Tea Extract (GTE) improves differentiation in human osteoblasts during oxidative stress. JOURNAL OF INFLAMMATION-LONDON 2014; 11:15. [PMID: 24904236 PMCID: PMC4045989 DOI: 10.1186/1476-9255-11-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 05/08/2014] [Indexed: 12/22/2022]
Abstract
Background Oxidative stress is involved in the pathogenesis of bone diseases such as osteoporosis, which has a high coincidence with fractures in elderly. Several studies showed positive effects of herbal bioactive substances on oxidative stress. This study analyses the effect of green tea extract (GTE) Sunphenon 90LB on primary human osteoblasts differentiation and viability during H2O2-induced oxidative stress. Moreover, it was analyzed, whether GTE acts during the HO-1 signaling pathway. Methods Human osteoblasts were isolated from femoral heads of patients undergoing total hip replacement. Beneficial effects of GTE on osteoblasts were examined in a dose- and time-dependent manner. Furthermore, GTE was given before, simultaneous with and after induction of oxidative stress with 1 mM H2O2 to simulate prophylactic, acute and therapeutic use, respectively. Cell damage was measured by LDH leakage and cell viability by MTT assay. Flow cytometry was applied to measure formation of Reactive Oxygen Species by using 2`7`-dichlorofluorescein-diacetate. The formation of Extracellular Matrix after differentiation with GTE supplementation during oxidative stress was visualized with von Kossa and Alizarin Red staining. Last one was additionally photometrically quantified. To assess the effects of H2O2 and GTE on the osteogenic genes, RT-PCR was performed. To evaluate the intramolecular influence of GTE after the stimulation the protein levels of HO-1 were analyzed. Results Stimulation of primary human osteoblasts with low doses of GTE during oxidative stress over 21 days improved mineralization. Furthermore, GTE supplementation in combination with H2O2 leads to a higher gene expression of osteocalcin and collagen1α1 during osteoblasts differentiation. Both are important for bone quality. Pre-incubation, co-incubation and post-incubation of osteoblasts with high doses of GTE protect the osteoblasts against acute oxidative stress as shown by increased cell viability, decreased LDH leakage, and reduced production of intracellular free radicals. Functional analysis revealed an increased HO-1 protein synthesis after stimulation with GTE. Conclusions Incubation of human primary osteoblasts with GTE significantly reduces oxidative stress and improves cell viability. GTE also has a beneficial effect on ECM production which might improve the bone quality. Our findings suggest that dietary supplementation of GTE might reduce inflammatory events in bone-associated diseases such as osteoporosis.
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Affiliation(s)
- Helen Vester
- Department of Trauma Surgery, Technical University Munich, MRI, Munich, Germany
| | - Nina Holzer
- Department of experimental Trauma Surgery, Technical University Munich, MRI, Munich, Germany
| | - Markus Neumaier
- Department of Trauma Surgery, Technical University Munich, MRI, Munich, Germany
| | - Schyschka Lilianna
- Department of experimental Trauma Surgery, Technical University Munich, MRI, Munich, Germany
| | - Andreas K Nüssler
- Department of experimental Trauma Surgery, Technical University Munich, MRI, Munich, Germany.,Department of Trauma Surgery, Eberhard Karls University Tubingen, Tubingen, Germany
| | - Claudine Seeliger
- Department of experimental Trauma Surgery, Technical University Munich, MRI, Munich, Germany
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9
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Willems BAG, Vermeer C, Reutelingsperger CPM, Schurgers LJ. The realm of vitamin K dependent proteins: shifting from coagulation toward calcification. Mol Nutr Food Res 2014; 58:1620-35. [PMID: 24668744 DOI: 10.1002/mnfr.201300743] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 12/27/2013] [Accepted: 01/01/2014] [Indexed: 12/20/2022]
Abstract
In the past few decades vitamin K has emerged from a single-function "haemostasis vitamin" to a "multi-function vitamin." The use of vitamin K antagonists (VKA) inevitably showed that the inhibition was not restricted to vitamin K dependent coagulation factors but also synthesis of functional extrahepatic vitamin K dependent proteins (VKDPs), thereby eliciting undesired side effects. Vascular calcification is one of the recently revealed detrimental effects of VKA. The discovery that VKDPs are involved in vascular calcification has propelled our mechanistic understanding of this process and has opened novel avenues for diagnosis and treatment. This review addresses mechanisms of VKDPs and their significance for physiological and pathological calcification.
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Affiliation(s)
- Brecht A G Willems
- Department of Biochemistry, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre, Maastricht, The Netherlands; VitaK BV, Maastricht University, Maastricht, The Netherlands
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10
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Portela G, Cerci D, Pedrotti G, Araujo M, Deliberador T, Zielak J, Costa-Casagrande T, Gonzaga C, Giovanini A. L-PRP diminishes bone matrix formation around autogenous bone grafts associated with changes in osteocalcin and PPAR-γ immunoexpression. Int J Oral Maxillofac Surg 2014; 43:261-8. [DOI: 10.1016/j.ijom.2013.07.739] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 07/04/2013] [Accepted: 07/09/2013] [Indexed: 01/06/2023]
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11
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Malashkevich VN, Almo SC, Dowd TL. X-ray crystal structure of bovine 3 Glu-osteocalcin. Biochemistry 2013; 52:8387-92. [PMID: 24138653 DOI: 10.1021/bi4010254] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 3 Glu form of osteocalcin (3 Glu-OCN) is increased in serum during low vitamin K intake or oral anticoagulant use (warfarin). Previous reports using circular dichroism show it is less structured than 3 Gla Ca²⁺-osteocalcin and does not bind strongly to bone mineral. Recent studies have suggested a role for 3 Glu-OCN as a potential regulator of glucose metabolism. A G-protein-coupled receptor, GPRC6a, found in the pancreas and testes was identified as the putative osteocalcin receptor. The purpose of this study is to determine the high-resolution structure of bovine 3 Glu-OCN, using X-ray crystallography, to understand molecular interactions with mineral and the GPRC6a receptor. Diffraction quality crystals of thermally decarboxylated bovine osteocalcin were grown, and the crystal structure was determined to 1.88 Å resolution. The final refined structure contained residues 17-47 and, like 3 Gla Ca²⁺-OCN, consisted of three α-helices surrounding a hydrophobic core, a C23-C29 disulfide bond between two of the helices, and no bound Ca²⁺. Thus, the helical structure of 3 Glu-OCN is Ca²⁺-independent but similar to that of 3 Gla Ca²⁺-OCN. A reduced level of mineral binding could result from a lower number of Ca²⁺ coordinating ligands on 3 Glu-OCN. The structure suggests the GPRC6a receptor may respond to helical osteocalcin and will aid in providing molecular mechanistic insight into the role of 3 Glu-OCN in glucose homeostasis.
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Affiliation(s)
- Vladimir N Malashkevich
- Department of Biochemistry, Albert Einstein College of Medicine , Bronx, New York 10461, United States
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12
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Neve A, Corrado A, Cantatore FP. Osteocalcin: skeletal and extra-skeletal effects. J Cell Physiol 2013; 228:1149-53. [PMID: 23139068 DOI: 10.1002/jcp.24278] [Citation(s) in RCA: 239] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 10/29/2012] [Indexed: 12/15/2022]
Abstract
Osteocalcin (OC) is a non-collagenous, vitamin K-dependent protein secreted in the late stage of osteoblasts differentiation. The presence of the three residues of γ-carbossiglutamatic acid, specific of the active form of OC protein, allows the protein to bind calcium and consequently hydroxyapatite. The osteoblastic OC protein is encoded by the bone γ-carbossiglutamate gene whose transcription is principally regulated by the Runx2/Cbfa1 regulatory element and stimulated by vitamin D(3) through a steroid-responsive enhancer sequence. Even if data obtained in literature are controversial, the dual role of OC in bone can be presumed as follows: firstly, OC acts as a regulator of bone mineralization; secondly, OC regulates osteoblast and osteoclast activity. Recently the metabolic activity of OC, restricted to the un-carboxylated form has been demonstrated in osteoblast-specific knockout mice. This effect is mediated by the regulation of pancreatic β-cell proliferation and insulin secretion and adiponectin production by adipose tissue and leads to the regulation of glucose metabolism and fat mass. Nevertheless, clinical human studies only demonstrated the correlation between OC levels and factors related to energy metabolism. Thus further investigations in humans are required to demonstrate the role of OC in the regulation of human energy metabolism. Moreover, it is presumable that OC also acts on blood vessels by inducing angiogenesis and pathological mineralization. This review highlights the recent studies concerning skeletal and extra-skeletal effects of OC.
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Affiliation(s)
- Anna Neve
- Department of Medical and Surgical Sciences, Rheumatology Clinic, University of Foggia, Foggia, Italy
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El-Gendy R, Yang XB, Newby PJ, Boccaccini AR, Kirkham J. Osteogenic differentiation of human dental pulp stromal cells on 45S5 Bioglass® based scaffolds in vitro and in vivo. Tissue Eng Part A 2012; 19:707-15. [PMID: 23046092 DOI: 10.1089/ten.tea.2012.0112] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The increasing clinical demand for bone substitutes has driven significant progress in cell-based therapies for bone tissue engineering. The underpinning goals for success are to identify the most appropriate cell source and to provide three-dimensional (3D) scaffolds that support cell growth and enhance osteogenic potential. In this study, human dental pulp stromal cells (HDPSCs) were cultured under basal or osteogenic conditions either in monolayers or on 3D Bioglass® scaffolds in vitro for 2 or 4 weeks. Cell-scaffold constructs were also implanted intraperitoneally in nude mice for 8 weeks. Osteogenic potential was assessed using quantitative real-time polymerase chain reaction and histological/immunohistochemical assays. In monolayer culture, osteoinductive conditions enhanced HDPSC expression of osteogenic gene markers (COL1A1, RUNX2, OC, and/or OCN) compared with basal conditions while culture of HDPSCs on 3D scaffolds promoted osteogenic gene expression compared with monolayer culture under both basal and osteogenic conditions. These results were confirmed using histological and immunohistochemical analyses. In vivo implantation of the HDPSC 3D Bioglass constructs showed evidence of sporadic woven bone-like spicules and calcified tissue. In conclusion, this study has demonstrated the potential of using a combination of HDPSCs with 3D 45S5 Bioglass scaffolds to promote bone-like tissue formation in vitro and in vivo, offering a promising approach for clinical bone repair and regeneration.
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Affiliation(s)
- Reem El-Gendy
- Biomaterials and Tissue Engineering Group, Leeds Dental Institute, University of Leeds, Leeds, United Kingdom
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Neve A, Corrado A, Cantatore FP. Osteoblast physiology in normal and pathological conditions. Cell Tissue Res 2010; 343:289-302. [PMID: 21120535 DOI: 10.1007/s00441-010-1086-1] [Citation(s) in RCA: 220] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Accepted: 11/03/2010] [Indexed: 12/13/2022]
Abstract
Osteoblasts are mononucleated cells that are derived from mesenchymal stem cells and that are responsible for the synthesis and mineralization of bone during initial bone formation and later bone remodelling. Osteoblasts also have a role in the regulation of osteoclast activity through the receptor activator of nuclear factor κ-B ligand and osteoprotegerin. Abnormalities in osteoblast differentiation and activity occur in some common human diseases such as osteoporosis and osteoarthritis. Recent studies also suggest that osteoblast functions are compromised at sites of focal bone erosion in rheumatoid arthritis.
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Affiliation(s)
- Anna Neve
- Rheumatology Clinic, Department of Medical and Occupational Sciences, University of Foggia, Foggia, Italy
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15
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Vater C, Lode A, Bernhardt A, Reinstorf A, Heinemann C, Gelinsky M. Influence of different modifications of a calcium phosphate bone cement on adhesion, proliferation, and osteogenic differentiation of human bone marrow stromal cells. J Biomed Mater Res A 2010; 92:1452-60. [PMID: 19373921 DOI: 10.1002/jbm.a.32469] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Collagen and noncollagenous proteins of the extracellular bone matrix are able to stimulate bone cell activities and bone healing. The modification of calcium phosphate bone cements used as temporary bone replacement materials with these proteins seems to be a promising approach to accelerate new bone formation. In this study, we investigated adhesion, proliferation, and osteogenic differentiation of human bone marrow stromal cells (hBMSC) on Biocement D/collagen composites which have been modified with osteocalcin and O-phospho-L-serine. Modification with osteocalcin was carried out by its addition to the cement precursor before setting as well as by functionalization of the cement samples after setting and sterilization. hBMSC were cultured on these samples for 28 days with and without osteogenic supplements. We found a positive impact especially of the phosphoserine-modifications but also of both osteocalcin-modifications on differentiation of hBMSC indicated by higher expression of the osteoblastic markers matrix metalloproteinase-13 and bone sialo protein II. For hBMSC cultured on phosphoserine-containing composites, an increased proliferation has been observed. However, in case of the osteocalcin-modified samples, only osteocalcin adsorbed after setting and sterilization of the cement samples was able to promote initial adhesion and proliferation of hBMSC. The addition of osteocalcin before setting results in a finer microstructure but the biological activity of osteocalcin might be impaired due to the sterilization process. Thus, our data indicate that the initial adhesion and proliferation of hBMSC is enhanced rather by the biological activity of osteocalcin than by the finer microstructure.
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Affiliation(s)
- Corina Vater
- Max Bergmann Center of Biomaterials, Technische Universität Dresden, Institute of Materials Science, Dresden, Germany
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16
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Shapira L, Halabi A. Behavior of two osteoblast-like cell lines cultured on machined or rough titanium surfaces. Clin Oral Implants Res 2009; 20:50-5. [PMID: 19126108 DOI: 10.1111/j.1600-0501.2008.01594.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Two osteosarcoma-derived cell lines have been extensively used to investigate the biological events occurring on titanium surfaces: MG63 and Saos-2. However, the behavior of the two lines on different titanium surfaces has never been compared. AIM The aim of the present study was to compare the behavior of MG63 and Saos-2 cells on two different titanium surfaces, machined and rough (sandblasting and acid-etched). We compared cell proliferation and morphology, alkaline phosphatase (ALP) activity and secretion of osteocalcin (OC). RESULTS The most pronounced difference between the two cell lines was that ALP activity in the Saos-2 cells was 10-fold higher than in the MG63 cells. The proliferation rate of the MG63 cells was much higher than that of the Saos-2 cells at all the tested cell concentrations. MG-63 cells, but not Saos-2 cells, grown on rough surface titanium proliferated more rapidly than cells grown on machined surfaces. Morphological analysis revealed that Saos-2 cells and cells grown on the rougher surface, displayed a more mature phenotype. The level of OC secreted by the Saos-2 cells, but not the MG63 cells, were higher on the rough surface than on the machined surface. CONCLUSIONS This study shows that Saos-2 cells exhibit a more mature osteoblast phenotype, compared with that of MG63 cells, rendering them a good candidate for an in vitro model of osseointegration.
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Affiliation(s)
- Lior Shapira
- Department of Periodontology, Faculty of Dental Medicine, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.
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Cuenot F, Meyer M, Espinosa E, Bucaille A, Burgat R, Guilard R, Marichal-Westrich C. New Insights into the Complexation of Lead(II) by 1,4,7,10-Tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane (DOTAM): Structural, Thermodynamic, and Kinetic Studies. Eur J Inorg Chem 2008. [DOI: 10.1002/ejic.200700819] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Kebsch M, Wilkinson M, Petocz P, Darendeliler MA. The effect of fluoride administration on rat serum osteocalcin expression during orthodontic movement. Am J Orthod Dentofacial Orthop 2007; 131:515-24. [PMID: 17418719 DOI: 10.1016/j.ajodo.2005.04.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 04/01/2005] [Accepted: 04/01/2005] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Osteocalcin is a bone protein that has been used to mark bone turnover. The precise role of this protein in bone remodeling has not been fully elucidated; however, it was shown to be instrumental in the activation of osteoclastic bone resorption via its effect on osteoblasts. Fluoride influences bone growth by acting as a mitogenic agent for osteoblasts. In this study, we used a rodent model to determine the effects of fluoride administration on systemic osteocalcin during orthodontic tooth movement. METHODS Thirty-two 8-week-old female Wistar rats were divided into 4 groups. The first experimental group (n = 10) was fed a normal laboratory diet and distilled water (MilliQ). The second experimental group (n = 10) had the same diet with the addition of fluoridated water. All animals in both groups had 100-g nickel-titanium coil springs secured to their mandibular incisors and left first molars to instigate orthodontic tooth movement for 14 days. The third (n = 6) and fourth (n = 6) groups were the controls. These animals did not undergo orthodontic tooth movement and were given fluoridated (100 ppm sodium fluoride) and nonfluoridated water ad libitum. Phlebotomy was performed via the lateral tail vein before placement of the orthodontic appliances, and final blood samples were obtained via cardiac puncture after the rats were killed 2 weeks later. Serum was isolated from the samples after centrifuging at each stage of phlebotomy, and an enzyme-linked immunosorbent assay (ELISA) was subsequently performed to determine osteocalcin levels in the various sample groups. RESULTS Orthodontic tooth movement with high, continuous forces was found to have a positive, statistically significant correlation with serum osteocalcin expression in the rodent model. The use of fluoride as a variable was found to increase the mean osteocalcin concentration, but this was not statistically significant. CONCLUSIONS Further understanding of the biological implications of increased osteocalcin expression requires additional research into the local expression of this protein in the gingival crevice during orthodontic movement.
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Affiliation(s)
- Mark Kebsch
- Discipline of Orthodontics, Sydney Dental Hospital, University of Sydney, Sydney, Australia
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Hiyama S, Sugiyama T, Kusuhara S, Uchida T. Cellular and molecular phenotypes of osteogenic cells isolated from the medullary bone of the hen in vitro. Comp Biochem Physiol B Biochem Mol Biol 2005; 142:419-25. [PMID: 16236535 DOI: 10.1016/j.cbpb.2005.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Revised: 09/09/2005] [Accepted: 09/10/2005] [Indexed: 11/23/2022]
Abstract
In this study, cells isolated from hen medullary bone were cultured to examine their matrix formation. Furthermore, we compared medullary bone cells with rat bone marrow cells regarding the temporal changes in osteoblast developmental markers. Medullary bone cells were positive for alkaline phosphatase (ALP) activity and formed bone nodules, apparent with Alcian blue and von Kossa staining. The intensity of these stains became stronger with the maturation of those bone nodules. In this developmental process, the expression patterns of osteoblast phenotypes of medullary bone cells differed from those of rat bone marrow cells. ALP mRNA was expressed at the maximum level in the proliferation stage and gradually decreased in medullary bone cells, but that expression showed the opposite pattern in rat bone marrow cells. Medullary bone cells strongly expressed two non-collagenous protein mRNAs from the early stages, but the expression of these mRNAs in rat bone marrow cells increased only in the later stages. These results suggest that the features of medullary bone osteoblasts differ from those of mammalian osteoblasts and are reflected in the characteristics of medullary bone in vivo.
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Affiliation(s)
- Shinji Hiyama
- Department of Oral Biology, Division of Molecular Medical Science, Hiroshima University Graduate School of Biomedical Sciences, Kasumi 1-2-3, Japan.
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Silva TA, Rosa AL, Lara VS. Dentin matrix proteins and soluble factors: intrinsic regulatory signals for healing and resorption of dental and periodontal tissues? Oral Dis 2004; 10:63-74. [PMID: 14996275 DOI: 10.1111/j.1601-0825.2004.00992.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Dentin contains numerous polypeptides and signaling molecules sequestered in a mineralized matrix. The exposure and release of these molecules occur as a consequence of injury to the pulp and periodontal ligament, which may result from luxation, orthodontic movement or infections of tooth and periodontal structures. When released at these sites, dentin constituents have the potential to act on different surrounding cells, including periodontal cells, osteoblasts, osteoclasts and inflammatory cells, and to affect the course of dental disease. Experimental studies have highlighted the interactions between dentin and cells from tooth and periodontal tissues and reveal dentin to be a cell adhesive, signaling and migratory stimulus for various mesenchymal and inflammatory cells. These results support the hypothesis that dentin molecules might function as regulatory signals for the healing and resorption of dental and periodontal tissues. Data from recent and classical investigations are summarized, many open questions are discussed, and current hypotheses concerning the mechanisms of tooth resorption and periodontal healing are outlined. Many questions regarding the importance of dentin as a source of multifunctional molecules remain unanswered and provide important directions for future studies.
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Affiliation(s)
- T A Silva
- Department of Stomatology, Faculty of Dentistry of Bauru, University of São Paulo, São Paulo, Brazil.
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Zhang H, Ahmad M, Gronowicz G. Effects of transforming growth factor-beta 1 (TGF-beta1) on in vitro mineralization of human osteoblasts on implant materials. Biomaterials 2003; 24:2013-20. [PMID: 12628820 DOI: 10.1016/s0142-9612(02)00616-6] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
An in vitro cell-implant mineralization model system was used to study the effect of transforming growth factor-beta 1(TGF-beta1) on mineralization in human osteoblast cultures. SaOs-2 and primary human osteoblast (HOB) cells were cultured on Tivanium (Ti-6Al-4V) disks. Administration of different concentrations of TGF-beta1 (0.02, 0.01, 0.2, 1.0, 2.0ng/ml) to these cultures demonstrated a biphasic dose response with 0.2ng/ml TGF-beta1 maximally increasing the calcium content compared to control culture. Results with SaOs-2 and HOB cultures were similar. An optimal dose of TGF-beta1 (0.2ng/ml) was provided to the cultures either in one single dose or multiple doses. Continuous administration of 0.2ng/ml TGF-beta1 caused 77% (SaOs-2) and 60% (HOB) increases in calcification compared to the control and 0.2ng/ml single dose groups. Single administration of the accumulative dose at 1.6ng/ml had no significant effect on the calcium content in either cell culture compared to control. Two weeks continuous administration of 0.2ng/ml TGF-beta1 in both cell cultures resulted in significant increases in the expression of bone specific extracellular matrix proteins which included alkaline phosphatase, Type I collagen, and osteocalcin as measured by Northern blot analysis and RT-PCR. At 4 weeks, the mRNA level of Type I collagen was still significantly higher in the TGF-beta1 treatment group compared to control. In conclusion, TGF-beta1 enhances mineralization of HOB on implant materials.
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Affiliation(s)
- Hai Zhang
- Department of Orthopaedic Surgery, University of Connecticut Health Center, MC 3105, Farmington, CT 06030-1110, USA
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22
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Göllner H, Dani C, Phillips B, Philipsen S, Suske G. Impaired ossification in mice lacking the transcription factor Sp3. Mech Dev 2001; 106:77-83. [PMID: 11472836 DOI: 10.1016/s0925-4773(01)00420-8] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Sp3 is a ubiquitously expressed member of the Sp family of transcription factors. Recently, the mouse Sp3 gene has been disrupted by homologous recombination. Sp3 null mice die immediately after birth due to respiratory failure. In addition, these mice show a pronounced defect in late tooth formation. Here we show that Sp3 is also required for proper skeletal ossification. Both endochondral and intramembranous ossification are impaired in E18.5 Sp3-/- embryos. The delay in ossification is reflected by reduced expression of the osteoblast-specific marker gene osteocalcin. The transcription factor - core binding factor 1 (Cbfa1)--that is essential for bone formation, however, is expressed at normal levels. In vitro differentiation studies using Sp3-/- ES cells further support the conclusion that Sp3 is needed for correct bone formation. The capacity of Sp3-/- cells to undergo osteogenic differentiation in vitro is reduced and osteocalcin expression is significantly diminished. Our studies establish Sp3 as an essential transcription factor for late bone development.
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Affiliation(s)
- H Göllner
- Institut für Molekularbiologie und Tumorforschung, Emil-Mannkopff-Strasse 2, 35037, Marburg, Germany
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Dowd TL, Rosen JF, Mints L, Gundberg CM. The effect of Pb(2+) on the structure and hydroxyapatite binding properties of osteocalcin. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1535:153-63. [PMID: 11342004 DOI: 10.1016/s0925-4439(00)00094-6] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Lead toxicity is a major environmental health problem in the United States. Bone is the major reservoir for body lead. Although lead has been shown to impair bone metabolism in animals and at the cellular level, the effect of Pb(2+) at the molecular level is largely unknown. We have used circular dichroism (CD), and a hydroxyapatite binding assay to investigate the effect of Pb(2+) on the structure and mineral binding properties of osteocalcin, a noncollagenous bone protein. The CD data indicate Pb(2+) induces a similar structure in osteocalcin as Ca(2+) but at 2 orders of magnitude lower concentration. These results were explained by the more than 4 orders of magnitude tighter binding of Pb(2+) to osteocalcin (K(d)=0.085 microM) than Ca(2+) (K(d)=1.25 mM). The hydroxyapatite binding assays show that Pb(2+) causes an increased adsorption to hydroxyapatite, similar to Ca(2+), but at 2-3 orders of magnitude lower concentration. Low Pb(2+) levels (1 microM) in addition to physiological Ca(2+) levels (1 mM) caused a significant (40%) increase in the amount of mineral bound osteocalcin as compared to 1 mM Ca(2+) alone. These results suggest a molecular mechanism of Pb(2+) toxicity where low Pb(2+) levels can inappropriately perturb Ca(2+) regulated processes. In-vivo, the increased mineral bound osteocalcin could play a role in the observed low bone formation rates and decreased bone density observed in Pb(2+)-intoxicated animals.
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Affiliation(s)
- T L Dowd
- Department of Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY 10467, USA.
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Greenberger JS, Goff JP, Bush J, Bahnson A, Koebler D, Athanassiou H, Domach M, Houck RK. Expansion of hematopoietic stem cells in vitro as a model system for human tissue engineering. Orthop Clin North Am 2000; 31:499-510. [PMID: 10882474 DOI: 10.1016/s0030-5898(05)70167-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The authors have taken a new approach to finding optimal conditions for stimulating conservative division of single isolated CD34(+)lin(-) hematopoietic stem cell candidates from human umbilical cord blood. The approach required the design and development of a novel multi-well single cell combinatorial culture system. This system incorporates the use of a multi-well tissue culture plate in which each well receives a single hematopoietic stem cell candidate. During an experiment lasting several days to weeks, each cell-containing well is moved sequentially and serially to a microscopic imaging system. This movement is facilitated by computer control of a motorized stage and stabilization of the experiment in an environmentally controlled Biobox built on the microscopic stage. New image analysis software facilitates tracking of cell movement, recording the time of cell division, and immunophenotyping of multiple, individual, or recently doubled cells in real time by a robotically controlled pipetting station. The principles of single cell culture should help solve many problems in human hematopoietic stem cell expansion and may be applicable to a wide range of other systems of interest in tissue engineering.
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Affiliation(s)
- J S Greenberger
- Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA
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Greenberger JS, Goff JP, Bush J, Bahnson A, Koebler D, Athanassiou H, Domach M, Houck RK. Expansion Of Hematopoietic Stem Cells In Vitro As A Model System For Human Tissue Engineering. Clin Plast Surg 1999. [DOI: 10.1016/s0094-1298(20)32657-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Lian JB, Stein GS, Stein JL, van Wijnen AJ. Regulated expression of the bone-specific osteocalcin gene by vitamins and hormones. VITAMINS AND HORMONES 1999; 55:443-509. [PMID: 9949687 DOI: 10.1016/s0083-6729(08)60941-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- J B Lian
- Department of Cell Biology, University of Massachusetts Medical Center, Worcester 01655, USA
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27
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Affiliation(s)
- P Newman
- Vitamin K Laboratory, Haemophilia Centre, St. Thomas's Hospital, London, England
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28
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Matsuoka H, Nakamura T, Takadama H, Yamada S, Tamura J, Okada Y, Oka M, Kokubo T. Osteoclastic resorption of bone-like apatite formed on a plastic disk as an in vitro assay system. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1998; 42:278-85. [PMID: 9773824 DOI: 10.1002/(sici)1097-4636(199811)42:2<278::aid-jbm13>3.0.co;2-f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have investigated the applicability of a simple and inexpensive osteoclastic assay system using bone-like apatite-coated polyethyleneterephthalate (PET) disks. A 1 microm thick apatite layer, uniform and homogeneous bone-mineral-like with no organic components, was made on PET disks using a biomimetic process. As substrates for an osteoclastic assay, these coated disks were compared with dentine as well as with bone-like or heat-treated apatite of various thicknesses on apatite- and wollastonite-containing glass ceramic (A-W GC) disks. The unfractionated bone cells, including osteoclasts, of a neonatal rabbit were seeded onto these substrates. By scanning electron microscopic examination, the resorption lacunae of the thick bone-like apatite clearly showed track-like shapes at various depths, similar to those of dentine although the border between the A-W GC and the apatite was unclear. In contrast, those of heat-treated apatite showed small and shallow shapes with irregular margins, quite different from those of dentine. By reducing the thickness of bone-like apatite to 1 microm as well as using PET as its substrate, the margins of the resorption lacunae became quite clear, and with the use of phase-contrast microscopy during culture, osteoclasts and resorption pits could be precisely observed. The resorbed area, easily measured with the aid of bright-field microscopy and an image analyzer, was found to have increased in a time-dependent manner and at the end of 4 days of culture was not statistically different from that of dentine.
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Affiliation(s)
- H Matsuoka
- Department of Orthopaedic Surgery, Faculty of Medicine, Kyoto University, Japan
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29
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Boskey AL, Gadaleta S, Gundberg C, Doty SB, Ducy P, Karsenty G. Fourier transform infrared microspectroscopic analysis of bones of osteocalcin-deficient mice provides insight into the function of osteocalcin. Bone 1998; 23:187-96. [PMID: 9737340 DOI: 10.1016/s8756-3282(98)00092-1] [Citation(s) in RCA: 288] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Osteocalcin, the gamma-carboxyglutamic acid-containing protein, which in most species is the predominant noncollagenous protein of bone and dentin, has been postulated to play roles in bone formation and remodeling. Recently, genetic studies showed that osteocalcin acts as an inhibitor of osteoblast function. Based on von Kossa staining and measurement of mineral apposition rates in tetracycline-labeled bones, osteocalcin knockout animals were reported to have no detectable alterations in bone mineralization. To test the hypothesis that, in addition to regulating osteoblastic activity, osteocalcin is involved in regulating mineral properties, a more sensitive assay of mineralization, Fourier transform infrared microspectroscopy (FT-IRM) was used to study thin sections of femora of 4-week-, 6-month- (intact and ovariectomized), and 9-month-old wild-type and osteocalcin-knockout mice. FT-IRM spectra provided spatially resolved measures of relative mineral and carbonate contents, and parameters indicative of apatite crystal size and perfection. No differences were detected in the mineral properties of the 4-week-old knockout and wild-type mice indicating that the mineralization process was not altered at this time point. Six-month-old wild-type animals had higher mineral contents (mineral:matrix ratios) in cortical as compared with trabecular bones; mineral contents in knockout and wild-type bones were not different. At each age studied, carbonate:phosphate ratios tended to be greater in the wild-type as compared with knockout animals. Detailed analysis of the phosphate nu1,nu3 vibrations in the spectra from 6-month-old wild-type animals indicated that the crystals were larger/more perfect in the cortical as opposed to the trabecular bones. In contrast, in the knockout animals' bones at 6 months, there were no differences between trabecular and cortical bone in terms of carbonate content or crystallite size and perfection. Spectral parameters of the cortical and trabecular bone of the knockout animals resembled those in the wild-type trabecular bone and differed from wild-type cortical bone. In ovariectomized 6-month-old animals, the mineral content (mineral:matrix ratio) in the wild-type cortices increased from periosteum to endosteum, whereas, in the knockout animals' bones, the mineral:matrix ratio was constant. Ovariectomized knockout cortices had lower carbonate:phosphate ratios than wild-type, and crystallite size and perfection resembled that in wild-type trabeculae, and did not increase from periosteum to endosteum. These spatially resolved data provide evidence that osteocalcin is required to stimulate bone mineral maturation.
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Affiliation(s)
- A L Boskey
- Mineralized Tissue Research Section, Hospital for Special Surgery, New York, NY 10021, USA.
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30
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White C, Gardiner E, Eisman J. Tissue specific and vitamin D responsive gene expression in bone. Mol Biol Rep 1998; 25:45-61. [PMID: 9540066 DOI: 10.1023/a:1006820710966] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Studies of gene expression in bone have adopted a number of molecular approaches that seek to determine those cis and trans-acting factors responsible for the development and physiological regulation of this unique tissue. The majority of studies have been performed in vitro, focussing on the expression of genes such as osteocalcin, bone sialoprotein and type I collagen which demonstrate restricted or altered expression patterns in osteoblasts. These studies have demonstrated a large number of cis and trans acting factors that modulate the tissue specific and vitamin D responsive expression of these genes. These include the response elements and regions mediating basal and vitamin D dependent transcription of these genes as well as some of the transcription factors that bind to these regions and the nucleosomal organisation of these genes within a nuclear framework. In vivo studies, including the introduction of transgenes into transgenic mice, extend these in vitro observations within a physiological context. However, in part due to limitations in each approach, these in vitro and in vivo studies are yet to accurately define all the necessary cis and trans-acting factors required for tissue specific and vitamin D responsive gene expression. Advances have been made in identifying many cis-acting regions within the flanking regions of these genes that are responsible for their restricted expression patterns, but a vector incorporating all the necessary cis-acting regions capable of directing gene expression independent of integration site has not yet been described. Similarly, trans-acting factors that determine the developmental destiny of osteoblast progenitors and the restricted expression of these genes remain elusive and, despite advances in the understanding of protein-DNA interactions at vitamin D response elements contained within these genes, further intermediary factors that interact with the transcriptional machinery to modulate vitamin D responsiveness need to be identified.
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Affiliation(s)
- C White
- Bone & Mineral Research Program, Garvan Institute of Medical Research, St Vincent's Hospital, Darlinghurst, Sydney, Australia
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Affiliation(s)
- I Schepetkin
- Department of Immunology, Tomsk Scientific Centre, Siberian Branch of Russian Academy of Medical Sciences, Russia
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Shearer MJ. The roles of vitamins D and K in bone health and osteoporosis prevention. Proc Nutr Soc 1997; 56:915-37. [PMID: 9483660 DOI: 10.1079/pns19970099] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- M J Shearer
- Vitamin K Research Unit, Haemophilia Centre, St Thomas's Hospital, London
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