1
|
Xu P, Cai X, Guan X, Xie W. Sulfoconjugation of protein peptides and glycoproteins in physiology and diseases. Pharmacol Ther 2023; 251:108540. [PMID: 37777160 PMCID: PMC10842354 DOI: 10.1016/j.pharmthera.2023.108540] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/02/2023]
Abstract
Protein sulfoconjugation, or sulfation, represents a critical post-translational modification (PTM) process that involves the attachment of sulfate groups to various positions of substrates within the protein peptides or glycoproteins. This process plays a dynamic and complex role in many physiological and pathological processes. Here, we summarize the importance of sulfation in the fields of oncology, virology, drug-induced liver injury (DILI), inflammatory bowel disease (IBD), and atherosclerosis. In oncology, sulfation is involved in tumor initiation, progression, and migration. In virology, sulfation influences viral entry, replication, and host immune response. In DILI, sulfation is associated with the incidence of DILI, where altered sulfation affects drug metabolism and toxicity. In IBD, dysregulation of sulfation compromises mucosal barrier and immune response. In atherosclerosis, sulfation influences the development of atherosclerosis by modulating the accumulation of lipoprotein, and the inflammation, proliferation, and migration of smooth muscle cells. The current review underscores the importance of further research to unravel the underlying mechanisms and therapeutic potential of targeting sulfoconjugation in various diseases. A better understanding of sulfation could facilitate the emergence of innovative diagnostic or therapeutic strategies.
Collapse
Affiliation(s)
- Pengfei Xu
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University, School of Pharmaceutical Sciences, Wuhan University, Wuhan 430072, China
| | - Xinran Cai
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Xiuchen Guan
- Department of Orthodontics, School of Stomatology, Capital Medical University, Beijing 100069, China
| | - Wen Xie
- Center for Pharmacogenetics and Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| |
Collapse
|
2
|
Terauchi M, Tamura A, Yamaguchi S, Yui N. Enhanced cellular uptake and osteogenic differentiation efficiency of melatonin by inclusion complexation with 2-hydroxypropyl β-cyclodextrin. Int J Pharm 2018; 547:53-60. [PMID: 29803791 DOI: 10.1016/j.ijpharm.2018.05.063] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/02/2018] [Accepted: 05/24/2018] [Indexed: 01/13/2023]
Abstract
Melatonin (MLT), a hormone secreted from the pineal gland, is recognized as a potential candidate for stimulation of bone regeneration. However, because of its hydrophobicity, the administration of MLT to stimulate bone regeneration is difficult. In this study, an inclusion complex of MLT with 2-hydroxypropyl β-cyclodextrin (HP-β-CD) was prepared to improve the water solubility, and the osteogenic differentiation ability of the inclusion complex was investigated in MC3T3-E1 cells. The formation of HP-β-CD/MLT inclusion complex was confirmed by 1H and 13C nuclear magnetic resonance spectroscopy and wide-angle X-ray diffraction. The water solubility of MLT increased linearly upon addition of HP-β-CD because of the formation of the inclusion complex. Additionally, treatment of the cells with HP-β-CD/MLT inclusion complex showed higher uptake amount of MLT than that treated with free MLT. In addition, treatment of MC3T3-E1 cells with HP-β-CD/MLT inclusion complex increased alkaline phosphatase activity and mineralized matrix deposition, compared to that in free MLT-treated and untreated cells. Furthermore, cells treated with HP-β-CD/MLT inclusion complex exhibited higher expression levels of osteogenic differentiation genes than those in the untreated and free MLT-treated cells. Accordingly, these results suggested that inclusion complexation of MLT with HP-β-CD would be a potential formulation for bone regeneration because of its improved solubility and enhanced osteogenic differentiation efficiency.
Collapse
Affiliation(s)
- Masahiko Terauchi
- Department of Organic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062, Japan; Department of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan
| | - Atsushi Tamura
- Department of Organic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062, Japan.
| | - Satoshi Yamaguchi
- Department of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo, Tokyo 113-8549, Japan
| | - Nobuhiko Yui
- Department of Organic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda, Tokyo 101-0062, Japan
| |
Collapse
|
3
|
Sirivisoot S, Webster TJ. In Situ Bone Growth Detection Using Carbon Nanotubes–Titanium Sensors. BIONANOSCIENCE 2013. [DOI: 10.1007/s12668-013-0079-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
4
|
Pre- and post-translational regulation of osteopontin in cancer. J Cell Commun Signal 2011; 5:111-22. [PMID: 21516514 DOI: 10.1007/s12079-011-0130-6] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 12/15/2022] Open
Abstract
Osteopontin (OPN) is a matricellular protein that binds to a number of cell surface receptors including integrins and CD44. It is expressed in many tissues and secreted into body fluids including blood, milk and urine. OPN plays important physiological roles in bone remodeling, immune response and inflammation. It is also a tumour-associated protein, and elevated OPN levels are associated with tumour formation, progression and metastasis. Research has revealed a promising role for OPN as a cancer biomarker. OPN is subject to alternative splicing, as well as post-translational modifications such as phosphorylation, glycosylation and proteolytic cleavage. Functional differences have been revealed for different isoforms and post-translational modifications. The pattern of isoform expression and post-translational modification is cell-type specific and may influence the potential role of OPN in malignancy and as a cancer biomarker.
Collapse
|
5
|
Yang Y, Cui Q, Sahai N. How does bone sialoprotein promote the nucleation of hydroxyapatite? A molecular dynamics study using model peptides of different conformations. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:9848-9859. [PMID: 20438109 DOI: 10.1021/la100192z] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Bone sialoprotein (BSP) is a highly phosphorylated, acidic, noncollagenous protein in bone matrix. Although BSP has been proposed to be a nucleator of hydroxyapatite (Ca(5)(PO(4))(3)OH), the major mineral component of bone, no detailed mechanism for the nucleation process has been elucidated at the atomic level to date. In the present work, using a peptide model, we apply molecular dynamics (MD) simulations to study the conformational effect of a proposed nucleating motif of BSP (a phosphorylated, acidic, 10 amino-acid residue sequence) on controlling the distributions of Ca(2+) and inorganic phosphate (Pi) ions in solution, and specifically, we explore whether a nucleating template for orientated hydroxyapatite could be formed in different peptide conformations. Both the alpha-helical conformation and the random coil structure have been studied, and inorganic solutions without the peptide are simulated as reference. Ca(2+) distributions around the peptide surface and interactions between Ca(2+) and Pi in the presence of the peptide are examined in detail. From the MD simulations, although in some cases for the alpha-helical conformation, we observe that a Ca(2+) equilateral triangle forms around the surface of peptide, which matches the distribution of Ca(2+) ions on the (001) face of the hydroxyapatite crystal, we do not consistently find a stable nucleating template formation in general for either the helical conformation or the random coil structure. Therefore, independent of conformations, the BSP nucleating motif is more likely to help nucleate an amorphous calcium phosphate cluster, which ultimately converts to crystalline hydroxyapatite.
Collapse
Affiliation(s)
- Yang Yang
- Department of Geoscience, University of Wisconsin, Madison, 1215 West Dayton Street, Madison, Wisconsin 53706, USA
| | | | | |
Collapse
|
6
|
Zhang J, Tu Q, Chen J. Applications of transgenics in studies of bone sialoprotein. J Cell Physiol 2009; 220:30-4. [PMID: 19326395 DOI: 10.1002/jcp.21768] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Bone sialoprotein (BSP) is a major non-collagenous protein in mineralizing connective tissues such as dentin, cementum and calcified cartilage tissues. As a member of the Small Integrin-Binding Ligand, N-linked Glycoprotein (SIBLING) gene family of glycoproteins, BSP is involved in regulating hydroxyapatite crystal formation in bones and teeth, and has long been used as a marker gene for osteogenic differentiation. In the most recent decade, new discoveries in BSP gene expression and regulation, bone remodeling, bone metastasis, and bone tissue engineering have been achieved with the help of transgenic mice. In this review, we discuss these new discoveries obtained from the literatures and from our own laboratory, which were derived from the use of transgenic mouse mutants related to BSP gene or its promoter activity.
Collapse
Affiliation(s)
- Jin Zhang
- Division of Oral Biology, Tufts University School of Dental Medicine, Boston, Massachusetts 02111, USA
| | | | | |
Collapse
|
7
|
Zhang J, Zhu J, Valverde P, Li L, Pageau S, Tu Q, Nishimura R, Yoneda T, Yang P, Zheng W, Ma W, Chen J. Phenotypic analysis of Dlx5 overexpression in post-natal bone. J Dent Res 2008; 87:45-50. [PMID: 18096892 DOI: 10.1177/154405910808700107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Dlx5 plays an important role in the embryonic development of mineralized tissues. We hypothesized that Dlx5 also functions in regulating post-natal bone formation in mice. To prove this hypothesis, we infected 5-day-old bone sialoprotein (BSP)/avian retroviral receptor gene (TVA) transgenic mice with replication-competent retroviral vectors expressing wild-type Dlx5 (RCAS-Dlx5WT) and mutated Dlx5 at arginine (R) 31 of its homeodomain (RCAS-Dlx5RH). Immunohistochemistry indicated that RCAS-Dlx5WT increased BSP and osteopontin (OPN) expression, whereas it decreased that of osteocalcin (OC). RCAS-Dlx5RH mediated opposite effects. Semi-quantitative RT-PCR confirmed these results. Ex vivo overexpression of RCAS-Dlx5WT in BSP/TVA calvarial cells promoted, whereas that of RCAS-Dlx5RH inhibited, mineralized nodule formation as compared with that in control cells. Our results suggest that Dlx5 promotes expression of early markers of osteogenic differentiation and increases mineralization post-natally.
Collapse
Affiliation(s)
- J Zhang
- Division of Oral Biology, Department of General Dentistry, Tufts University School of Dental Medicine, One Kneeland Street, Boston, MA 02111, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Cabras T, Fanali C, Monteiro JA, Amado F, Inzitari R, Desiderio C, Scarano E, Giardina B, Castagnola M, Messana I. Tyrosine Polysulfation of Human Salivary Histatin 1. A Post-Translational Modification Specific of the Submandibular Gland. J Proteome Res 2007; 6:2472-80. [PMID: 17503797 DOI: 10.1021/pr0700706] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Histatin 1 (His-1) derivatives showing serial mass increases of 80.0 +/- 0.1 Da were detected in human saliva by HPLC-ESI-MS. The same derivatives were also found in granules of submandibular glands and secretions of submandibular/sublingual glands, but not in granules and secretions of parotid glands. Only one phosphate group was present in His-1 and its derivatives, since treatment with alkaline phosphatase provided an 80.0 Da mass decrease. His-1 derivatives were almost completely transformed into His-1 by treatment with 1 M HCl at 100 degrees C, suggesting the presence of O-sulfotyrosine, which is more labile than phospho-Tyr to acidic hydrolysis. CE-MS analysis of pronase extensive digestion of derivatives confirmed the presence of sulfotyrosine. Derivatives were digested by trypsin, proteinase K, and protease V-8 and analyzed by different MS strategies. The results allowed locating sulfation on the last four tyrosines (Tyr 27, 30, 34, and 36). This study is the first report of the gland-specific sulfation of a salivary phosphopeptide in vivo.
Collapse
Affiliation(s)
- Tiziana Cabras
- Department of Sciences Applied to Biosystems, Cagliari University, Cagliari, Italy
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Li L, Zhu J, Tu Q, Yamauchi M, Sodek J, Karsenty G, Tang J, Chen J. An in vivo model to study osteogenic gene regulation: targeting an avian retroviral receptor (TVA) to bone with the bone sialoprotein (BSP) promoter. J Bone Miner Res 2005; 20:1403-13. [PMID: 16007338 DOI: 10.1359/jbmr.050316] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2004] [Revised: 03/14/2005] [Accepted: 03/16/2005] [Indexed: 11/18/2022]
Abstract
UNLABELLED To study bone development in vivo, a transgenic mouse model was established in which an avian retroviral receptor (TVA) gene driven by the BSP promoter was selectively expressed in skeletal tissues. The model was validated by showing suppressed BSP expression and delayed bone and tooth formation after infection with a virus expressing a mutated Cbfa1/Runx2 gene. INTRODUCTION Tissue-specific expression of the avian retroviral (TVA) receptor can be used to efficiently target ectopic expression of genes in vivo. To determine the use of this approach for studies of osteogenic differentiation and bone formation at specific developmental stages, transgenic mice expressing the TVA receptor under the control of a 5-kb bone sialoprotein (BSP) promoter were generated. The mice were first analyzed for tissue-specific expression of the TVA gene and then, after infection with a viral construct, for the effects of a dominant-negative form of the Cbfa1/Runx2 transcription factor on bone formation. MATERIALS AND METHODS We first generated transgenic mice (BSP/TVA) in which the TVA gene was expressed under the control of a 4.9-kb mouse BSP promoter. The tissue-specific expression of the TVA gene was analyzed by RT-PCR, in situ hybridization, and immunohistochemistry and compared with the expression of the endogenous BSP gene. A 396-bp fragment of mutated Cbfa1/Runx2 (Cbfa1mu) encoding the DNA-binding domain was cloned into a RCASBP (A) viral vector, which was used to infect neonatal BSP/TVA mice. RESULTS AND CONCLUSION Expression of the TVA receptor mRNA and protein in the transgenic mice was consistent with the expression of endogenous BSP. Four days after systemic infection with the Cbfa1mu-RCASBP (A) vector, RT-PCR analyses revealed that the expression of BSP mRNA in tibia and mandibles was virtually abolished, whereas a 30% reduction was seen in calvarial bone. After 9 days, BSP expression in the tibia and mandible was reduced by 45% in comparison with control animals infected with an empty RCASBP vector, whereas BSP expression in the membranous bone of calvariae was decreased approximately 15%. However, after 4 and 8 weeks, there was almost no change in BSP expression in any of the bone tissues. In comparison, a reduction in osteopontin expression was only observed 9 days after viral transfection in the three bones. Histomorphological examination revealed that bone formation and tooth development were delayed in some of the mice infected with mutated Cbfa1. These studies show that BSP/TVA transgenic mice can be used to target genes to sites of osteogenesis, providing a unique system for studying molecular events associated with bone formation in vivo.
Collapse
Affiliation(s)
- Ling Li
- Division of Oral Biology, Tufts School of Dental Medicine, Boston, Massachusetts 02111, USA
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Keykhosravani M, Doherty-Kirby A, Zhang C, Brewer D, Goldberg HA, Hunter GK, Lajoie G. Comprehensive Identification of Post-translational Modifications of Rat Bone Osteopontin by Mass Spectrometry†. Biochemistry 2005; 44:6990-7003. [PMID: 15865444 DOI: 10.1021/bi050109p] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Osteopontin (OPN) is a highly modified protein that is found in many tissues and has been associated with a variety of physiological and pathological processes. Bone OPN is a potent inhibitor of hydroxyapatite crystal formation and stimulates bone resorption by osteoclasts; these activities, as well as others, are dependent upon phosphorylation of the protein. We have used mass spectrometry (MS) to perform a comprehensive analysis of the post-translational modification of OPN purified from rat bone. Matrix-assisted laser desorption time-of-flight (MALDI-TOF) MS showed masses of 37.6 and 36.8 kDa before and after enzymatic dephosphorylation, respectively, corresponding to a content of approximately 10.4 phosphate groups. Using proteolytic digestion and tandem MS, we localized 29 sites of phosphorylation: S10, S11, S46, S47, T50, S60, S62, S65, S146, T154, S160, S164, S167, S193, S196, S203, S220, S223, S232, S241, S245, S257, S262, S267, S278, S290, S295, S296, and S297. In addition, Y150 was shown to be sulfated and T107, T110, T116, and T121 are O-glycosylated. No glycan was detected at the potential N-glycosylation site. Other modifications, including deamidation, oxidation, and carbamylation, are also present. A 36-amino acid sequence from residues 67-102 could not be analyzed in detail, even after sialidase treatment, presumably because of the presence of a large number of acidic residues. In comparison to the previously characterized cow milk isoform, rat bone OPN is sulfated and has an additional site of glycosylation, many different sites of phosphorylation, and a lower overall phosphate content.
Collapse
Affiliation(s)
- Mandana Keykhosravani
- CIHR Group in Skeletal Development and Remodeling, School of Dentistry, The University of Western Ontario, London, Ontario, N6A 5C1, Canada
| | | | | | | | | | | | | |
Collapse
|
11
|
Midura RJ, Wang A, Lovitch D, Law D, Powell K, Gorski JP. Bone Acidic Glycoprotein-75 Delineates the Extracellular Sites of Future Bone Sialoprotein Accumulation and Apatite Nucleation in Osteoblastic Cultures. J Biol Chem 2004; 279:25464-73. [PMID: 15004030 DOI: 10.1074/jbc.m312409200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Addition of an organophosphate source to UMR osteoblastic cultures activates a mineralization program in which BSP localizes to extracellular matrix sites where hydroxyapatite crystals are subsequently nucleated. This study identifies for the first time novel extracellular spherical structures, termed biomineralization foci (BMF), containing bone acidic glycoprotein-75 (BAG-75), bone sialoprotein (BSP), and alkaline phosphatase that are the exclusive sites of initial nucleation of hydroxyapatite crystals in the UMR model. Importantly, in the absence of added phosphate, UMR cultures after reaching confluency contain two size populations of morphologically identifiable BMF precursors enriched in BAG-75 (15-25 and 150-250 microm in diameter). The shape and size of the smaller population are similar to structures assembled in vitro through self-association of purified BAG-75 protein. After organophosphate addition, BSP accumulates within these BAG-75-containing BMF precursors, with hydroxyapatite crystal nucleation occurring subsequently. In summary, BAG-75 is the earliest detectable biomarker that accurately predicts the extracellular sites of de novo biomineralization in UMR cultures. We hypothesize that BAG-75 may perform a key structural role in the assembly of BMF precursors and the recruitment of other proteins such as alkaline phosphatase and BSP. Furthermore, we propose a hypothetical mechanism in which BAG-75 and BSP function actively in nucleation of apatite within BMF.
Collapse
Affiliation(s)
- Ronald J Midura
- Department of Biomedical Engineering and the Orthopaedic Research Center, Lerner Research Institute, The Cleveland Clinic and Foundation, Cleveland, Ohio 44195, USA
| | | | | | | | | | | |
Collapse
|
12
|
Cogan G, Bansal AK, Ibrahim S, Zhu B, Goldberg HA, Ganss B, Cheifetz S, Armbruster FP, Sodek J. Analysis of human bone sialoprotein in normal and pathological tissues using a monoclonal antibody (BSP 1.2 mab). Connect Tissue Res 2004; 45:60-71. [PMID: 15203941 DOI: 10.1080/03008200490278151] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Bone sialoprotein (BSP), a phosphorylated and sulphated glycoprotein that is expressed by mineralized connective tissues is also produced in tumors that metastasize to bone. To facilitate studies of BSP expression in normal and pathological human tissues a monoclonal antibody (BSP 1.2 mab) was raised against human bone BSP. BSP 1.2 mab was shown by ELISA assays to recognize the epitope "DEYSY" (amino acids 279-283) that is conserved in mammalian BSP sequences. However, whereas the antibody recognized recombinant BSPs expressed in bacteria, it did not recognize native forms of rat or pig BSP in which the first tyrosine of the DEYSY peptide sequence appears to be modified. Immunostaining of embryonic human tibiae and calvariae with BSP 1.2 mab showed strong reaction in osteoblasts and osteocytes with relatively weak staining of the bone matrix, suggesting that the BSP 1.2 mab epitope is partially masked in the bone matrix. BSP 1.2 mab also stained osteosarcoma cells and normal trophoblastic cells in the placenta in areas of microcrystalline deposits. Cancer cells in primary breast tumors, lymph nodes, and secondary bone metastases from individual patients were stained strongly by BSP 1.2 mab. Although BSP 1.2 mab also stained breast cancer carcinoma cell lines and SaOS2 osteosarcoma cells, biosynthesis of radiolabelled BSP could not be demonstrated in breast cancer cells. Notably, the staining of BSP in the breast cancer cells was diffuse contrasting the punctate staining, typical of secreted proteins, in SaOS2 cells. These studies, therefore, have identified a unique epitope in human BSP recognized by a monoclonal antibody, BSP 1.2 mab, which can be used for the unequivocal identification of BSP in normal and pathological human tissues.
Collapse
Affiliation(s)
- Gabrielle Cogan
- Canadian Institutes of Health Research Group in Matrix Dynamics, Faculty of Dentistry, University of Toronto, Ontario, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Onnerfjord P, Heathfield TF, Heinegård D. Identification of tyrosine sulfation in extracellular leucine-rich repeat proteins using mass spectrometry. J Biol Chem 2003; 279:26-33. [PMID: 14551184 DOI: 10.1074/jbc.m308689200] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Multiple and variable tyrosine sulfation in extracellular class II leucine-rich repeat proteins/proteoglycans were characterized by mass spectrometry. The sulfogroup on tyrosine is labile and is released from peptides under normal mass spectrometric conditions. Thus, special approaches must be considered in order to identify this modification. By using a combination of mass spectrometry studies operating in negative and positive ion mode, tyrosine sulfation could be identified. In positive mode, the peptides normally appeared non-sulfated, whereas in negative mode a mixture of sulfated and non-sulfated species was observed. A combination of peptides released by different proteinases was used to obtain details on the locations of sulfate groups. Multiple tyrosine sulfates were observed in the N-terminal region of fibromodulin (up to 9 sites), osteoadherin (up to 6 sites), and lumican (2 sites). Osteoadherin contains two additional sulfated tyrosine residues close to its C terminus. We also identified an error in the published sequence of bovine fibromodulin, resulting in the replacement of Thr37 by Tyr37-Gly38, thus increasing its homology with its human counterpart.
Collapse
Affiliation(s)
- Patrik Onnerfjord
- Department of Cell and Molecular Biology, Section for Connective Tissue Biology, Lund University, BMC C12, 221 84 Lund, Sweden
| | | | | |
Collapse
|
14
|
Zaia J, Boynton R, Heinegård D, Barry F. Posttranslational modifications to human bone sialoprotein determined by mass spectrometry. Biochemistry 2001; 40:12983-91. [PMID: 11669636 DOI: 10.1021/bi010887r] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bone sialoprotein (BSP) is an acidic 301 amino acid protein expressed by osteoblasts and at a low level by hypertrophic chondrocytes. Its expression is highest during early stages of bone formation, and it is particularly abundant in the cells lining the surface of newly formed trabeculae. BSP contains numerous substituents which are anionic in nature and apparently essential for the function of the protein. Thus, the proposed role of BSP in hydroxyapatite nucleation and growth may depend on such modifying groups. The posttranslational modifications include several acidic oligosaccharides as well as phosphate and sulfate groups. This work combines matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry with selective enzyme treatment of BSP to provide new information on the precise distribution and structure of oligosaccharides, sulfate, and phosphate groups in BSP isolated from human bone. The results provide a high level of detail in the location of these modifying groups toward the end of providing a basis for further understanding the function of BSP in bone nucleation.
Collapse
Affiliation(s)
- J Zaia
- Osiris Therapeutics, Inc., Baltimore, Maryland 21231, USA
| | | | | | | |
Collapse
|
15
|
Harris NL, Rattray KR, Tye CE, Underhill TM, Somerman MJ, D'Errico JA, Chambers AF, Hunter GK, Goldberg HA. Functional analysis of bone sialoprotein: identification of the hydroxyapatite-nucleating and cell-binding domains by recombinant peptide expression and site-directed mutagenesis. Bone 2000; 27:795-802. [PMID: 11113390 DOI: 10.1016/s8756-3282(00)00392-6] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mammalian bone sialoprotein (BSP) is a mineralized tissue-specific protein containing an RGD (arginine-glycine-aspartic acid) cell-attachment sequence and two distinct glutamic acid (glu)-rich regions, with each containing one contiguous glu sequence. These regions have been proposed to contribute to the attachment of bone cells to the extracellular matrix and to the nucleation of hydroxyapatite (HA), respectively. To further delineate the domains responsible for these activities, porcine BSP cDNA was used to construct expression vectors coding for two partial-length recombinant BSP peptides: P2S (residues 42-87), containing the first glutamic acid-rich domain; and P1L (residues 69-300), containing the second glutamic acid-rich region and the RGD sequence. These peptides were expressed in Escherichia coli as his-tag fusion proteins and purified by nickel affinity columns and FPLC chromatography. Digestion with trypsin released the his-tag fusion peptide, which generated P2S-TY (residues 42-87) and P1L-TY (residues 132-239). Using a steady-state agarose gel system, P2S-TY promoted HA nucleation, whereas P2S, P1L, and P1L-TY did not. This implies that the minimum requirement for nucleation of HA resides within the amino acid sequence of the first glutamic acid-rich domain, whereas the second glutamic acid-rich domain may require posttranslational modifications for activity. P1L, but not P2S, promoted RGD-mediated attachment of human gingival fibroblasts in a manner similar to that of native BSP. Deletion of the RGD domain or conversion of it to RGE (arginine-glycine-glutamic acid) abolished the cell-attachment activity of P1L. This suggests that, at least for human gingival fibroblasts, the major cell-attachment activity in the recombinant BSP peptides studied (residues 42-87 and 69-300) requires the RGD sequence located at the C-terminal domain.
Collapse
Affiliation(s)
- N L Harris
- Department of Biochemistry, Faculty of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Wang A, Martin JA, Lembke LA, Midura RJ. Reversible suppression of in vitro biomineralization by activation of protein kinase A. J Biol Chem 2000; 275:11082-91. [PMID: 10753913 DOI: 10.1074/jbc.275.15.11082] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Parathyroid hormone (PTH-(1-34)) potently suppresses apatite deposition in osteoblastic cultures. These inhibitory effects are mediated through signaling events following PTH receptor binding. Using both selective inhibitors and activators of protein kinase A (PKA), this study shows that a transient activation of PKA is sufficient to account for PTH's inhibition of apatite deposition. This inhibition is not a result of reduced cell proliferation, reduced alkaline phosphatase activity, increased collagenase production, or lowering medium pH. Rather, data suggest a functional relationship between matrix assembly and apatite deposition in vitro. Bone sialoprotein (BSP) and apatite co-localize in the extracellular matrix of mineralizing cultures, with matrix deposition of BSP temporally preceding that of apatite. Transient activation of PKA by either PTH-(1-34) or short term cAMP analog treatment blocks the deposition of BSP in the extracellular matrix without a significant reduction in the total amount of BSP synthesized and secreted. This effect is reversible after allowing the cultures to recover in the absence of PKA activators for several days. Thus, a transient activation of PKA may suppress mineral deposition in vitro as a consequence of altering the assembly of an extracellular matrix permissive for apatite formation.
Collapse
Affiliation(s)
- A Wang
- Department of Biomedical Engineering, The Lerner Research Institute of The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
| | | | | | | |
Collapse
|
17
|
Roth JA, Kim BG, Lin WL, Cho MI. Melatonin promotes osteoblast differentiation and bone formation. J Biol Chem 1999; 274:22041-7. [PMID: 10419530 DOI: 10.1074/jbc.274.31.22041] [Citation(s) in RCA: 221] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Prior studies have demonstrated that the pineal hormone, melatonin, can stimulate chloramphenicol acetyltransferase activity in Drosophila SL-3 cells transfected with a chloramphenicol acetyltransferase reporter construct containing the response element of rat bone sialoprotein (BSP). Based on these findings, studies were performed to determine whether melatonin could similarly modulate the expression of BSP in two cell lines, the MC3T3-E1(MC3T3) pre-osteoblast and rat osteoblast-like osteosarcoma 17/2.8 cell. Initial studies demonstrated that MC3T3 cells grown in the presence of 50 nM melatonin underwent cell differentiation and mineralization by day 12 instead of the 21-day period normally required for cells grown in untreated media. Melatonin increased gene expression of BSP and the other bone marker proteins, including alkaline phosphatase (ALP); osteopontin; secreted protein, acidic and rich in cysteine; and osteocalcin in MC3T3 cells in a concentration-dependent manner. Levels of melatonin as low as 10 nM were capable of stimulating transcription of these genes when cells were grown in the presence of beta-glycerophosphate and ascorbic acid. Under these conditions, melatonin induced gene expression of the bone marker proteins; however, this does not occur until the 5th day after seeding the culture dishes. Thereafter, MC3T3 cells responded to melatonin within 2 h of treatment. The fully differentiated rat osteoblast-like osteosarcoma 17/2.8 cells responded rapidly to melatonin and displayed an increase in the expression of BSP, ALP, and osteocalcin genes within 1 h of exposure to the hormone. To determine whether melatonin-induced osteoblast differentiation and bone formation are mediated via the transmembrane receptor, MC3T3 cells were treated in the presence and absence of melatonin with either luzindole, a competitive inhibitor of the binding of melatonin to the transmembrane receptors, or pertussis toxin, an uncoupler of G(i) from adenylate cyclase. Both luzindole and pertussis toxin were shown to reduce melatonin-induced expression of BSP and ALP. These results demonstrate, for the first time, that the pineal hormone, melatonin, is capable of promoting osteoblast differentiation and mineralization of matrix in culture and suggest that this hormone may play an essential role in regulating bone growth.
Collapse
Affiliation(s)
- J A Roth
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, State University of New York, Buffalo, New York 14214, USA
| | | | | | | |
Collapse
|
18
|
Bearinger JP, Castner DG, Healy KE. Biomolecular modification of p(AAm-co-EG/AA) IPNs supports osteoblast adhesion and phenotypic expression. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 1998; 9:629-52. [PMID: 9686332 DOI: 10.1163/156856298x00064] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Interpenetrating polymer networks (IPNs) were designed to resist materials fouling caused by non-specific protein adsorption, and indiscriminate cell or bacterial adhesion. These IPNs were thin adherent films (approximately 20 nm) comprised of acrylamide (AAm), ethylene glycol (EG), and acrylic acid (AA) grafted to either silicon waters or quartz substrates via photoinitiated free radical polymerization. These networks were further modified to promote specific cell adhesion by tethering bioactive groups such as peptides that mimic cell-binding domains found on extracellular matrix molecules. As a specific example of biomolecular surface engineering, peptides from the cell-binding domain of bone sialoprotein were tethered to a p(AAm-co-EG/AA) IPN to control cell behavior at the surface. The networks were characterized by contact angle measurements, spectroscopic ellipsometry, and X-ray photoelectron spectroscopy to convey information on IPN wettability, thickness, and chemistry. The surface characterization data supported the theory that the PEG/AA layer formed an IPN with the underlying p(AAm) network, and after graft modification of this IPN with diamino PEG (PEG(NH2)2), the PEG(NH2)2 chains were enriched at the surface. Rat calvarial osteoblasts attached to Arg-Gly-Asp (RGD) modified IPNs at levels significantly greater than on clean quartz, Arg-Gly-Glu (RGE) modified, or the PEG(NH2)2 modified IPN, with or without serum in the media. Cells maintained in media containing 15% fetal bovine serum (FBS) proliferated, exhibited nodule formation, and generated sheets of mineralized extracellular matrix (ECM) with the addition on beta-glycerophosphate to the media. Cell adhesion and mineralized ECM formation were specifically dependent on the peptide sequence present at the surface.
Collapse
Affiliation(s)
- J P Bearinger
- Division of Biological Materials, Northwestern University Dental School, Chicago, IL 60611-3008, USA
| | | | | |
Collapse
|
19
|
Stubbs JT, Mintz KP, Eanes ED, Torchia DA, Fisher LW. Characterization of native and recombinant bone sialoprotein: delineation of the mineral-binding and cell adhesion domains and structural analysis of the RGD domain. J Bone Miner Res 1997; 12:1210-22. [PMID: 9258751 DOI: 10.1359/jbmr.1997.12.8.1210] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Bone sialoprotein is a small, sulfated, and phosphorylated integrin-binding glycoprotein apparently found only in tissues that eventually mineralize. Nondenatured bone sialoprotein (BSP) purified from rat osteosarcoma cell line (UMR 106-01 BSP) culture media is shown to have a hydroxyapatite Kd approximately 2.6 x 10(-9) M, perhaps the strongest affinity for this mineral of any of the matrix proteins. Both native BSP and a 47 kD fragment of UMR-BSP (Fragment 1 approximately 133A- approximately 265Y) are more potent inhibitors of seeded hydroxyapatite crystal growth than recombinant human BSP fragments lacking post-translational modifications. The recombinant proteins, however, do show reproducible inhibitory activity, suggesting that at least some of the strong mineral-binding properties are encoded directly within the protein sequence itself. BSP facilitates the adhesion of several cell types through its integrin binding (RGD) tripeptide sequence. Nuclear magnetic resonance (NMR) analysis of a 15N-enriched 59 amino acid recombinant domain containing the RGD tripeptide shows that the structure of this isolated domain is highly flexible with or without 5 mM calcium. Previous work has also shown that an endogenous fragment of UMR-BSP (Fragment 1) supports cell adhesion in the absence of the RGD sequence. In this report, non-RGD cell adhesion sites are localized within conserved amino- and carboxy-terminal tyrosine-rich domains of recombinant human BSP. Given the proximity of the latter non-RGD cell adhesion site to the RGD tripeptide, a model of BSP-receptor interactions is presented.
Collapse
Affiliation(s)
- J T Stubbs
- Craniofacial and Skeletal Diseases Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland, USA
| | | | | | | | | |
Collapse
|
20
|
Affiliation(s)
- D D Bosshardt
- Department of Stomatology, Faculty of Dentistry, University of Montreal, Quebec, Canada
| | | |
Collapse
|
21
|
Yang R, Gerstenfeld LC. Structural analysis and characterization of tissue and hormonal responsive expression of the avian bone sialoprotein (BSP) gene. J Cell Biochem 1997; 64:77-93. [PMID: 9015757 DOI: 10.1002/(sici)1097-4644(199701)64:1<77::aid-jcb11>3.0.co;2-h] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Bone sialoprotein (BSP) is an extracellular matrix protein that has a highly restricted expression to mineralized skeletal tissues. The chicken bone sialoprotein-encoding gene (bsp) was isolated and shown to contain two less exons than similar mammalian genes, with the absence of an untranslated 5' exon and the fusion of the first two exons that encode the signal peptide and amino terminal end of the mature BSP peptide. Primer extension analysis showed one strong transcriptional start point (tsp) in mRNA prepared from embryonic bone. Comparison of the avian bsp promoter sequence to those of other genes expressed in vertebrate skeletal tissues, identified the presence of homeobox protein binding sequence motifs for engrailed (en-1) and Msx 2 (Hox 8.1), and two collagen type II gene silencer elements. Two TATA sequences one at -21 bp and the second at -172 bp to the tsp were identified. For the first TATA element no CCAAT sequence was observed at an appropriate cis position however two Sp1 sequences (GGGCGG) were identified at -66 and -85 bp. A CCAAT element was seen in an appropriate cis position in relationship to the second upstream TATA, but transient expression analysis in embryonic chicken calvaria osteoblasts using two separate promoter/reporter constructs (+24 to -1244 bp or -121 to -1244 bp), confirmed that only the proximal TATA and Sp1 elements were functional. The +24 to -1244 bp promoter sequence demonstrated 33.6, 13.2, and 3.2 fold activity above base line respectively, within cells prepared from embryonic chicken calvaria bone, cephalic sterna, a cartilage that undergoes mineralization and caudal sterna, a cartilage that does not mineralize during embryogenesis. Only base line activity was observed within cells prepared from embryonic dermal fibroblasts a non-skeletal tissue, which does not express BSP. These same cells demonstrated comparable steady state mRNA levels, corroborating that this segment of promoter DNA had tissue specific activity. A series of nested deletions from the 5' end of the -1244 construct demonstrated that a portion of the tissue specific regulation was controlled by the presence of a silencer element(s) between -1244 and -620 bp since deletion of this segment of DNA resulted in a 6 fold increase in the promoter activity in dermal skin fibroblasts. The -1244-(+)24 nt promoter construct was shown to be stimulated by dexamethasome approximately 1.5 fold over control, inhibited by 1,25(OH)2D3 approximately 60% of control and was strongly stimulated approximately 5.0 fold by parathyroid hormone (PTH) in embryonic calvaria osteoblasts. These data define the proximal promoter of the avian bsp gene and identify several potential regulatory elements that have been observed in the promoters of other genes expressed in skeletal tissues. These elements imparted both tissue and hormone specific promoter activity to bsp expression within skeletal cells.
Collapse
Affiliation(s)
- R Yang
- Laboratory for the Study of Skeletal Disorders and Rehabilitation, Children's Hospital, Boston, Massachusetts 02115, USA
| | | |
Collapse
|
22
|
Abstract
Bone sialoprotein (BSP) is a major protein of the mineralized bone extracellular matrix that has been implicated in the nucleation of hydroxyapatite crystals. Our previous studies have demonstrated that BSP mRNA is expressed by differentiated osteoblasts, odontoblasts, and cementoblasts involved in de novo mineralized tissue formation in a tissue-specific and developmentally regulated manner. To determine the basis of the selective expression of the BSP gene, we have generated four transgenic mouse lines in which 2.7 kb of the rat BSP promoter ligated to a luciferase reporter gene has been stably integrated into the mouse genome. Assays of luciferase activities in 5-day-old animals has revealed consistently high levels in bone tissues with negligible activities in various other organs including kidney, liver, stomach, intestine, and spleen. In some animals, variable expression was observed in brain and skin. Temporal analyses revealed the highest luciferase expression in neonatal bones, with expression decreasing markedly with subsequent growth and development, as observed previously for the endogenous gene in rats. Immunohistochemical analysis of luciferase activity and in situ hybridization of luciferase mRNA in bone tissues show that differentiated osteoblasts express the highest levels of luciferase, consistent with the induction of endogenous gene expression. These studies demonstrate that the regulation of the BSP gene during osteoblastic differentiation, together with its tissue-specific, developmentally regulated expression, is primarily mediated within the 2.7 kb region of the promoter.
Collapse
Affiliation(s)
- J Chen
- Department of Pediatric Dentistry, The University of Texas Health Science Center, San Antonio, USA
| | | | | | | | | |
Collapse
|
23
|
Crosby AH, Lyu MS, Lin K, McBride OW, Kerr JM, Aplin HM, Fisher LW, Young MF, Kozak CA, Dixon MJ. Mapping of the human and mouse bone sialoprotein and osteopontin loci. Mamm Genome 1996; 7:149-51. [PMID: 8835534 DOI: 10.1007/s003359900037] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A H Crosby
- Department of Dental Medicine, University of Manchester, UK
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Arai N, Ohya K, Kasugai S, Shimokawa H, Ohida S, Ogura H, Amagasa T. Expression of bone sialoprotein mRNA during bone formation and resorption induced by colchicine in rat tibial bone marrow cavity. J Bone Miner Res 1995; 10:1209-17. [PMID: 8585425 DOI: 10.1002/jbmr.5650100811] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In the rat tibial bone marrow cavity, following colchicine injection, there is a phase of osteogenesis in which bone trabeculae replace the necrotic bone marrow tissues and fill the marrow cavity. The newly formed bone is subsequently resorbed by osteoclasts and normal bone marrow is restored. In this study, we correlated these morphologic events with the pattern of gene expression of bone sialoprotein (BSP), an extracellular matrix protein in mineralized tissues, to elucidate the possible functions of BSP in bone formation and resorption in vivo. The expressions of osteopontin (OPN) and type I collagen were also examined. Northern hybridization of the tibia demonstrated that OPN mRNA was gradually increased and expressed at a maximal level 10 days after colchicine injection (during the bone resorption process), while BSP mRNA expression already reached a maximal level at day 6 (during the initial process of bone formation). Its expression was, thus, quite temporary at the beginning of bone formation and different from that of type I collagen, which was continually elevated from days 6 to 10. In situ hybridization of the newly formed bone induced in the tibia revealed that BSP mRNA was evenly expressed in most osteoblasts and osteocytes, moreover in interconnecting colonies of spindle-shaped cells, possibly preosteoblasts, at day 6. At day 10, however, its expression became restricted to some cells on the bone surfaces, some osteoblasts, and most osteoclasts. These observations suggest that BSP may play an important role mainly in the initiation of bone formation and is also associated with the functions of osteoclast in vivo.
Collapse
Affiliation(s)
- N Arai
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tokyo Medical and Dental University, Japan
| | | | | | | | | | | | | |
Collapse
|
25
|
Zhou HY, Takita H, Fujisawa R, Mizuno M, Kuboki Y. Stimulation by bone sialoprotein of calcification in osteoblast-like MC3T3-E1 cells. Calcif Tissue Int 1995; 56:403-7. [PMID: 7621349 DOI: 10.1007/bf00301610] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Bone sialoprotein (BSP) containing an Arg-Gly-Asp cell-binding sequence was purified from bovine bone 4 M guanidine-HCl extract after HCl demineralization by a series of chromatographic procedures. When this protein was coated on culture dishes in the presence of type I collagen, it increased both DNA content and alkaline phosphatase (ALP) activity in osteoblast-like MC3T3-E1 cells, and stimulated calcification in the cells, whereas fibronectin, another cell-binding protein, showed a marked increase in the DNA content but had little effect on the ALP activity. These findings suggest that BSP is mitogenic for preosteoblasts and differentiating the cells into osteoblasts, thereby stimulating bone calcification.
Collapse
Affiliation(s)
- H Y Zhou
- Department of Biochemistry, School of Dentistry, Hokkaido University, Sapporo, Japan
| | | | | | | | | |
Collapse
|
26
|
Yang R, Gotoh Y, Moore MA, Rafidi K, Gerstenfeld LC. Characterization of an avian bone sialoprotein (BSP) cDNA: comparisons to mammalian BSP and identification of conserved structural domains. J Bone Miner Res 1995; 10:632-40. [PMID: 7610935 DOI: 10.1002/jbmr.5650100417] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Bone sialoprotein (BSP) is one of the major noncollagenous proteins found in mineralized vertebrate tissue. It is an acidic glycoprotein containing a high sialic acid content and is phosphorylated on several of its Ser and Thr residues. While it has been extensively characterized from various mammalian species, little is known about its sequence or expression in lower vertebrates. The cloning and characterization of several cDNAs encoding the chicken bone sialoprotein are reported here. A partial cDNA clone encoding the carboxyl terminus of the protein was initially isolated from a lambda GT11 expression library using a polyclonal antibody gains BSP purified from chicken bone matrix. Subsequently, several additional clones were obtained by further screening and by reverse transcription polymerase chain reaction (RT-PCR). Three overlapping clones encompassing about 1 kb, which included the complete coding sequence for BSP, were analyzed. The deduced amino acid sequence revealed that chicken BSP contains 276 amino acid residues. Although the overall identity between chicken and mammalian BSP is only approximately 39%, the diversity in amino acid sequence occurs mostly between the major functional domains of this molecule. These domains include: (1) three acidic poly-Glu regions; (2) two tyrosine-rich domains, which may be sites for protein sulfation; (3) several casein kinase II phosphorylation sites; (4) an Asn glycosylation site; and (5) an RGD cell-binding motif. Of interest in the chicken BSP is the identification of two additional RGD motifs within the avian sequence, unlike the mammalian forms of BSP which has only one.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- R Yang
- Department of Orthopaedic Surgery, Harvard Medical School, Children's Hospital, Boston, Massachusetts, USA
| | | | | | | | | |
Collapse
|
27
|
Masi L, Brandi ML, Robey PG, Crescioli C, Calvo JC, Bernabei P, Kerr JM, Yanagishita M. Biosynthesis of bone sialoprotein by a human osteoclast-like cell line (FLG 29.1). J Bone Miner Res 1995; 10:187-96. [PMID: 7754798 DOI: 10.1002/jbmr.5650100204] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Biosynthesis of bone sialoprotein (BSP) by a human osteoclastic cell line (FLG 29.1) during its differentiation induced by phorbol 12-myristate 13-acetate (TPA) was studied using metabolic radiolabeling experiments. The FLG 29.1 cells were metabolically radiolabeled with [3H]glucosamine and [35S]sulfate, and the labeled glycoproteins were analyzed by anion exchange chromatography, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoprecipitation experiments. One of the major glycoproteins synthesized by the TPA-treated FLG 29.1 cells was sulfated, had an identical electrophoretic mobility to purified BSP, and could be immunoprecipitated with a specific antibody against human BSP (LF 6). Thus, this glycoprotein was tentatively identified as the BSP. Furthermore, mRNA for BSP was also detected in TPA-treated FLG 29.1 cells by RNA-polymerase chain reaction. Most BSP synthesized by FLG 29.1 cells remained cell-associated, and this is in contrast with those synthesized by osteoblasts, where the protein is rapidly released into the extracellular matrix. Immunocytochemistry using an anti-BSP antibody showed a prominent paranuclear (suggestive of Golgi apparatus) localization of BSP in the TPA-treated FLG 29.1 cells after permeabilization, while untreated cells were not significantly immunostained. Localization of BSP at the plasma membrane was also demonstrated in the TPA-treated FLG 29.1 cells by the fluorescence-activated cell sorting analysis. Since TPA has been demonstrated to induce expression of various osteoclastic characteristics in FLG 29.1 cells, induction of BSP expression by TPA suggests that the protein may play a role during the differentiation process of osteoclasts or in functions of differentiated osteoclasts.
Collapse
Affiliation(s)
- L Masi
- Bone Research Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland, USA
| | | | | | | | | | | | | | | |
Collapse
|
28
|
Fujisawa R, Nodasaka Y, Kuboki Y. Further characterization of interaction between bone sialoprotein (BSP) and collagen. Calcif Tissue Int 1995; 56:140-4. [PMID: 7736323 DOI: 10.1007/bf00296346] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Bone sialoprotein (BSP) has an affinity to collagen fibrils [25]. A role of carbohydrate chains in the affinity was examined by removing sialic acids of BSP. Neuraminidase treatment of the BSP increased the binding to collagen. Binding sites of BSP on collagen were examined by biochemical and electron-microscopic methods. Purified bovine BSP was labeled with biotin. Collagen alpha chains or CNBr peptides were separated by electrophoresis and transfered to nitrocellulose membranes. The membranes were incubated with the biotin-labeled BSP, and the bound BSP was visualized with avidin conjugated with alkaline phosphatase. The labeled BSP was preferentially bound to the alpha 2 chain, and peptides derived from alpha 2 chain. In another experiment, the labeled BSP was incubated with reconstituted native collagen fibrils. The mixture was put on a copper grid, reacted with avidin conjugated with gold particles, and observed with an electron microscope. The gold particles were seen mainly within hole zones of the fibrils. BSP bound to the alpha 2 chain within the hole zones may regulate the onset of calcification at hole zones and the cell binding to collagen fibrils.
Collapse
Affiliation(s)
- R Fujisawa
- Department of Biochemistry, Hokkaido University School of Dentistry, Sapporo, Japan
| | | | | |
Collapse
|
29
|
Forbes EG, Cronshaw AD, MacBeath JR, Hulmes DJ. Tyrosine-rich acidic matrix protein (TRAMP) is a tyrosine-sulphated and widely distributed protein of the extracellular matrix. FEBS Lett 1994; 351:433-6. [PMID: 8082810 DOI: 10.1016/0014-5793(94)00907-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Tyrosine-rich acidic matrix protein (TRAMP; 22 kDa extracellular matrix protein; dermatopontin) is a protein that co-purifies with lysyl oxidase and with dermatan sulphate proteoglycans, with possible functions in cell-matrix interactions and matrix assembly. Using a rabbit polyclonal antiserum raised against porcine TRAMP, which cross-reacts with both the human and murine forms of the protein, we show by immunoblotting that TRAMP has a widespread tissue distribution, including skin, skeletal muscle, heart, lung, kidney, cartilage and bone. In cultures of human skin fibroblasts, TRAMP incorporates both [35S]sulphate and [3H]tyrosine and is secreted into the medium, as shown by immunoprecipitation. Amino acid analysis of immunoprecipitated TRAMP demonstrates that many of the tyrosine residues in TRAMP are sulphated.
Collapse
Affiliation(s)
- E G Forbes
- Department of Biochemistry, University of Edinburgh, UK
| | | | | | | |
Collapse
|
30
|
Abstract
Sulfation is the most abundant post-translational modification of tyrosine residues and occurs in many soluble and membrane proteins passing through the secretory pathway of metazoan cells. The sulfation reaction is catalysed by tyrosylprotein sulfotransferase, a membrane-bound enzyme of the trans-Golgi-network. Tyrosylprotein sulfotransferase has been purified and its substrate specificity characterized. Tyrosine sulfation has been shown to be important for protein-protein interactions occurring during the intracellular transport of proteins and upon their secretion.
Collapse
Affiliation(s)
- C Niehrs
- Institute for Neurobiology, University of Heidelberg, Germany
| | | | | |
Collapse
|
31
|
Farquharson C, Whitehead CC, Loveridge N. Alterations in glycosaminoglycan concentration and sulfation during chondrocyte maturation. Calcif Tissue Int 1994; 54:296-303. [PMID: 7520345 DOI: 10.1007/bf00295954] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We have used antibodies to chondroitin 4- and 6-sulfate and keratan sulfate along with Alcian blue staining of sulfated proteoglycans to investigate changes in content and sulfation within the avian growth plate. In normal chicks, chondroitin 4- and 6-sulfate content were similar in the proliferating and transitional zones but in the hypertrophic zone, chondroitin 4- and 6-sulfate were slightly lower (13% and 18%, respectively) and keratan sulfate was markedly lower (58%). Compared with the proliferative zone, Alcian blue staining of sulfated glycosaminoglycans was markedly lower in both the transitional (46%) and hypertrophic (22%) zones. In tibial dyschondroplasia, where chondrocyte maturation is arrested at the transitional zone, there was no difference in the chondroitin 4- and 6-sulfate or keratan sulfate staining between the proliferative and transitional zones, which were similar to normal birds. With Alcian blue staining there was no difference in the intensity of the staining within the proliferating zone compared with normal birds but staining in the transitional chondrocytes was markedly higher (39%). These results suggest that in the early steps of chondrocyte maturation there may be a decrease in the degree of glycosaminoglycan sulfation without any alteration in glycosaminoglycan concentration, and that further maturation may be accompanied by a change in the nature of the proteoglycans which may also affect the level of sulfation.
Collapse
Affiliation(s)
- C Farquharson
- AFRC Roslin Institute (Edinburgh), Roslin, Midlothian, Scotland
| | | | | |
Collapse
|
32
|
Chenu C, Ibaraki K, Gehron Robey P, Delmas PD, Young MF. Cloning and sequence analysis of bovine bone sialoprotein cDNA: conservation of acidic domains, tyrosine sulfation consensus repeats, and RGD cell attachment domain. J Bone Miner Res 1994; 9:417-21. [PMID: 7514841 DOI: 10.1002/jbmr.5650090318] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We isolated and sequenced a cDNA encoding bovine bone sialoprotein (BSP) using a bovine cDNA library made from mRNA isolated from bone-derived cell cultures and ligated to a phage lambda gt11. One of the cDNA clones isolated from this library had a 1800 base pair long insert and was found to contain the entire protein-encoding region. The deduced protein sequence revealed a 310 amino acid protein containing a signal peptide sequence of 16 hydrophobic amino acids. The protein sequence shows remarkable conservation with previously published human and rat sequences (more than 80% similarity for both species). The potential functional domains of BSP, including three acid amino acid-rich sequences, tyrosine sulfation consensus repeats, and the RGD cell binding sequence, are all present in the bovine sequence. Northern analysis of RNA from different bovine tissues indicated the presence of BSP message in bone but not in other nonmineralized tissues, confirming that bone is the major site of BSP message production.
Collapse
Affiliation(s)
- C Chenu
- INSERM Unité 234, Hôpital Edouard Herriot, Lyon, France
| | | | | | | | | |
Collapse
|
33
|
Yao KL, Todescan R, Sodek J. Temporal changes in matrix protein synthesis and mRNA expression during mineralized tissue formation by adult rat bone marrow cells in culture. J Bone Miner Res 1994; 9:231-40. [PMID: 8140936 DOI: 10.1002/jbmr.5650090212] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
To characterize the bone-like tissue produced by rat bone marrow cells (RBMC) from young adult femurs, the synthesis of bone proteins and the expression of their mRNA were studied in vitro. RBMC plated at a density of 5 x 10(3) cells/cm2 and grown in the presence of 10(-8) M dexamethasone (Dex) and 10 mM beta-glycerophosphate (beta-GP) produced mineralized bone nodules, which were first evident at day 3 and increased markedly to day 13. However, in the absence of dexamethasone, few mineralized nodules were observed. The formation of mineralized nodules was reflected by the uptake of 45Ca, which also increased markedly to day 13. Analysis of bone protein expression by Northern and slot-blot hybridizations revealed an increase in mRNA levels of collagen type I (Col I), osteonectin/SPARC (ON), alkaline phosphatase (ALP), osteopontin (OPN), bone sialoprotein (BSP), and osteocalcin (OC) during the formation of mineralized nodules. Whereas the Col I, ON, ALP, and OPN mRNAs were expressed before the formation of mineralized nodules was evident and were also expressed at various levels in the absence of Dex, the expression of BSP and OC mRNA was induced in the bone-forming cultures. The expression of BSP mRNA was correlated temporally with bone tissue formation, reaching maximal levels on day 16. In contrast, OC mRNA was expressed later and, following induction, increased over the 28 day culture period. Production of matrix proteins during the rapid formation of the bone tissue appeared to reflect the levels of the respective mRNAs. However, whereas some of the collagen and almost all of the SPARC were secreted into the culture medium, virtually all of the OPN and most of the BSP were extracted from the mineralized tissue matrix with EDTA. Some OPN and BSP were present in the medium, especially early in the culture, and a significant amount of BSP was also found associated with the collagenous tissue matrix. These studies point to the importance of Col I, ALP, OPN, and BSP, but not ON or OC, in the initial formation of bone tissue.
Collapse
Affiliation(s)
- K L Yao
- Medical Research Council Group in Periodontal Physiology, University of Toronto, Ontario, Canada
| | | | | |
Collapse
|
34
|
Chlorate-induced inhibition of tyrosine sulfation on bone sialoprotein synthesized by a rat osteoblast-like cell line (UMR 106-01 BSP). J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37621-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
35
|
Bone sialoprotein mRNA expression and ultrastructural localization in fetal porcine calvarial bone: comparisons with osteopontin. ACTA ACUST UNITED AC 1994. [DOI: 10.1007/bf02388394] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
36
|
Kim RH, Shapiro HS, Li JJ, Wrana JL, Sodek J. Characterization of the human bone sialoprotein (BSP) gene and its promoter sequence. Matrix Biol 1994; 14:31-40. [PMID: 8061918 DOI: 10.1016/0945-053x(94)90027-2] [Citation(s) in RCA: 80] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Bone sialoprotein (BSP) is a major structural protein of the bone matrix that is specifically expressed by fully-differentiated osteoblasts. To characterize the gene and to study the tissue-and differentiation stage-specific regulation of BSP gene transcription we have isolated and partially sequenced two overlapping genomic fragments which span the complete human BSP gene and its promoter region. The approximately 15 kb gene comprises seven exons of 82 bp, 68 bp, 51 bp, 78 bp, 63 bp, 159 bp and 2.5 kb (1-7, respectively), separated by six introns of approximately 3 kb, 92 bp, 95 bp, approximately 3 kb, approximately 0.5 kb and approximately 4.5 kb. All of the intron-exon boundaries defining the splice sites conform to the consensus sequence of: AG at the 3' splice site; and GT at the 5' splice site, except the 3' splice site of exon 1. The first exon encodes the 5'-UTR, the second exon the signal sequence and the first two amino acids, exons 3 and 4 the Tyr-and Phe-rich amino terminus, and exon 5 the first segment of polyglutamic acid. Exon 7 encodes over half of the protein including a second polyglutamic acid segment, the RGD cell attachment motif, the sulphated tyrosine-rich C-terminus and the 3'-UTR. The promoter region is characterized by an inverted TATA-like sequence (TTTATA), nts -28 to -23 from the transcriptional start site (+1), and an inverted CCAAT box (ATTGG) at -54 to -50. Analysis of chimeric constructs fused to a CAT reporter gene indicate that the presence of both the inverted TATA-like sequence and CCAAT elements are required for basal promoter activity. Comparison of the human BSP promoter with the rat BSP promoter (Li and Sodek, 1993) reveal that the nature and position of the inverted TATA-like sequence and CCAAT box together with an Ap1 (-148 to -142), CRE (-122 to -116) and a homeobox-binding site (-200 to -191) have been conserved. A putative Glucocorticoid Response Unit (GRU) consisting of a Glucocorticoid Response Element (GRE) and an overlapping direct repeat (DR5) similar to the retinoic acid receptor element (RARE) is present at -1038 to -1022. These studies have defined the structure of the human BSP gene and have identified novel transcriptional elements in the promoter that may be involved in the developmentally regulated, tissue specific expression of this gene.
Collapse
Affiliation(s)
- R H Kim
- Department of Biochemistry, University of Toronto, Ontario, Canada
| | | | | | | | | |
Collapse
|
37
|
van Dijk S, D'Errico JA, Somerman MJ, Farach-Carson MC, Butler WT. Evidence that a non-RGD domain in rat osteopontin is involved in cell attachment. J Bone Miner Res 1993; 8:1499-506. [PMID: 8304052 DOI: 10.1002/jbmr.5650081213] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The bone sialoprotein osteopontin (OPN) promotes cell attachment and spreading through its RGD (Arg-Gly-Asp) sequence. To study additional regions of OPN involved in cell attachment, peptides of rat OPN were evaluated for their capacity to mediate cell binding to wells in vitro. Human gingival fibroblasts were incubated on microtiter plates coated with either OPN or OPN peptides. A peptide of M(r) 28 kD, obtained after digestion with endoproteinase Arg-C and isolated by reversed-phase HPLC, enhanced cell attachment to a similar degree as OPN. Sequence analysis showed that the amino terminus of the 28 kD peptide starts at Ser142 and therefore does not contain the RGD cell attachment sequence (residues 128-130). Cell attachment mediated through both OPN and the 28 kD peptide was blocked by the addition of GRGDSPA peptides or LM-609, a monoclonal antibody to the integrin alpha V beta 3, a receptor for vitronectin. A variant peptide, GRG-ESPA, did not alter cell attachment. Based on these observations, we conclude that (1) binding of OPN and the 28 kD peptide to fibroblasts involves binding to alpha V beta 3, (2) a site other than the RGD sequence on OPN is also involved in binding to integrins, and (3) the binding of this second site to alpha V beta 3 is inhibited by RGD-containing peptides.
Collapse
Affiliation(s)
- S van Dijk
- Department of Basic Sciences, University of Texas Houston Health Science Center
| | | | | | | | | |
Collapse
|
38
|
Shapiro HS, Chen J, Wrana JL, Zhang Q, Blum M, Sodek J. Characterization of porcine bone sialoprotein: primary structure and cellular expression. MATRIX (STUTTGART, GERMANY) 1993; 13:431-40. [PMID: 8309422 DOI: 10.1016/s0934-8832(11)80109-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Bone sialoprotein (BSP) is a highly glycosylated and sulphated phosphoprotein that is a major non-collagenous protein of bone. To further characterize the porcine protein and to study its expression during bone formation BSP cDNA clones were isolated from a porcine bone cDNA library. The primary sequence of the protein was derived from the nucleotide sequence of the largest cDNA insert and from the amino-terminal amino acid sequence determined by the automated Edman degradation procedure. When compared with sequences obtained from the human and rat BSPs 74% and 64% of the amino acids, respectively, were identical and a further 11% and 17%, respectively, were conservative replacements. Moreover, 60% of the amino acids in a concensus sequence derived from the primary sequences of mammalian BSPs were conserved with 16% conservative replacements. The two stretches of polyglutamic acid, through which the protein is capable of binding to hydroxyapatite, and an RGD motif that mediates cell attachment are retained in conserved sequences as are a number of potential sites of serine, threonine and tyrosine phosphorylation, glycosylation and tyrosine sulphation. Secondary structure prediction and hydrophilicity analysis indicate that the nascent BSP has an open flexible structure with the potential to form significant amounts of alpha-helix and some beta-sheet. In situ hybridization of fetal porcine bone with cRNA probes to porcine BSP mRNA shows that BSP is specifically expressed in differentiated osteoblasts on the surface of newly-forming bone trabeculae with especially high levels of hybridization at sites of de novo bone formation. The highly conserved features of BSP and its restricted distribution indicate an important role for this sialoprotein in the formation of bone.
Collapse
Affiliation(s)
- H S Shapiro
- Medical Research Council Group in Periodontal Physiology, University of Toronto, Ontario
| | | | | | | | | | | |
Collapse
|
39
|
Cronshaw AD, MacBeath JR, Shackleton DR, Collins JF, Fothergill-Gilmore LA, Hulmes DJ. TRAMP (tyrosine rich acidic matrix protein), a protein that co-purifies with lysyl oxidase from porcine skin. Identification of TRAMP as the dermatan sulphate proteoglycan-associated 22K extracellular matrix protein. MATRIX (STUTTGART, GERMANY) 1993; 13:255-66. [PMID: 8100985 DOI: 10.1016/s0934-8832(11)80009-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A protein (M(r)24 K) that co-purifies with porcine skin lysyl oxidase (M(r)34 K) has been isolated and characterised. Five variants of the 24 K protein were identified by Mono Q ion-exchange FPLC, as were four variants of lysyl oxidase. Amino acid analysis and partial sequencing revealed near identity of a 36-residue CNBr peptide from porcine skin lysyl oxidase to corresponding regions of the putative lysyl oxidase precursor derived from rat and human cDNA. The 24 K protein was found to be unrelated to lysyl oxidase, but comparison with a protein sequence database showed it to be the same as a recently described protein from bovine skin that is associated with dermatan sulphate proteoglycans. The 24 K protein is relatively rich in tyrosine, and isoelectric focussing shows it to be acidic, with pI's in the range 4.1 to 4.4. In view of these properties, we propose the name TRAMP (Tyrosine Rich Acidic Matrix Protein) to identify this protein. Though TRAMP appears not to be glycosylated, several experiments indicate the presence of sulphotyrosine residues. When assayed using an elastin substrate, the activity of lysyl oxidase is unaffected by TRAMP.
Collapse
Affiliation(s)
- A D Cronshaw
- Department of Biochemistry, University of Edinburgh, UK
| | | | | | | | | | | |
Collapse
|
40
|
Chen J, McCulloch CA, Sodek J. Bone sialoprotein in developing porcine dental tissues: cellular expression and comparison of tissue localization with osteopontin and osteonectin. Arch Oral Biol 1993; 38:241-9. [PMID: 8489418 DOI: 10.1016/0003-9969(93)90034-j] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Bone sialoprotein (BSP) is a highly sulphated and glycosylated phosphoprotein that is a major constituent of bone and other mineralized connective tissues. Although BSP can mediate cell attachment through an RGD sequence and binds selectively to hydroxyapatite, its precise function in mineralized tissues is unknown. To provide insights into its possible function, affinity-purified polyclonal antibodies directed against porcine BSP were used to demonstrate the histological distribution of this protein in developing porcine mandibular alveolar bone and the associated tooth tissues from 35- and 50-day fetuses. In addition, a porcine cRNA probe was used to determine the cellular expression of BSP in the same tissues by in situ hybridization. Immunoreactivity to BSP protein was restricted to the cells and matrix of the mineralized tissues of alveolar bone and dentine. In dentine, BSP was localized to the odontoblasts and their processes and to the peritubular dentine. In the alveolar bone, immunoreactivity for BSP was evident in osteoblastic cells and osteocytes and in the bone matrix; the older bone stained more strongly than newly formed bone. In addition, BSP appeared to be concentrated in the reversal lines of the rapidly remodelling bone. The distribution of BSP in these tissues revealed distinct differences when compared to osteopontin and SPARC/osteonectin, which are also prominent non-collagenous proteins of mineralized tissues. Most notable was the localization of osteopontin and especially osteonectin in non-mineralizing tissues. The immunoreactivity of osteoblasts and osteocytes for BSP in bone was consistent with the high levels of BSP mRNA revealed by in situ hybridization. However, much lower levels of hybridization were evident in the odontoblasts of developing mandibular molars. These studies demonstrate that BSP is expressed during the early formation of dentine and alveolar bone and that the protein accumulates in the peritubular dentine and bone matrix.
Collapse
Affiliation(s)
- J Chen
- Medical Research Council Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, Ontario, Canada
| | | | | |
Collapse
|
41
|
Beresford JN, Graves SE, Smoothy CA. Formation of mineralized nodules by bone derived cells in vitro: a model of bone formation? AMERICAN JOURNAL OF MEDICAL GENETICS 1993; 45:163-78. [PMID: 8456798 DOI: 10.1002/ajmg.1320450205] [Citation(s) in RCA: 117] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The identification of the factors which regulate the proliferation and differentiation of cells of the osteoblast lineage remains one of the major challenges in the field of bone cell biology. Although considerable progress has been made in the isolation and culture of cells of the osteoblast lineage from both animal and, more recently, human bone, uncertainties have persisted as to the extent to which these cell populations retain the ability to differentiate into functional osteoblasts in vitro. The formation in vitro of mineralized nodules that exhibit the morphological, ultrastructural and biochemical characteristics of embryonic/woven bone formed in vivo, represents the first evidence that the differentiation of functional osteoblasts can occur in cultures of isolated animal bone-derived cell populations. It is clear, however, that the culture conditions employed at present only permit a small number of cells to differentiate to the extent of being capable of organising their extracellular matrix into a structure that resembles that of bone. Moreover, it has generally been found that the reproducible mineralization of this extracellular matrix requires supplementation of the culture medium with mM concentrations of beta-GP, which raises doubts as to the physiological relevance of this process. The formation of nodules has also been observed in cultures of human bone-derived cells. As found in cultures of animal bone-derived cells, reproducible mineralization of these nodules will occur in the presence of beta-GP. We have shown, however, that in the presence of the long acting ascorbate analogue Asc-2-P, the formation and mineralization of nodules can occur in the absence of beta-GP. The nodules formed in human bone-derived cell cultures have yet to be characterized as rigorously as those formed in cultures of animal bone-derived cells and thus it remains to be shown that they resemble bone formed in vivo.
Collapse
Affiliation(s)
- J N Beresford
- Medical Research Council Bone Research Laboratory, Nuffield Orthopaedic Centre, Headington, Oxford, United Kingdom
| | | | | |
Collapse
|
42
|
Kasugai S, Nagata T, Sodek J. Temporal studies on the tissue compartmentalization of bone sialoprotein (BSP), osteopontin (OPN), and SPARC protein during bone formation in vitro. J Cell Physiol 1992; 152:467-77. [PMID: 1510790 DOI: 10.1002/jcp.1041520305] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To study the role of noncollagenous proteins in bone formation, the synthesis and tissue distribution of BSP (bone sialoprotein), OPN (osteopontin) and SPARC (secreted protein acidic and rich in cysteine) were analyzed using pulse-chase and continuous labeling protocols during bone formation by cultures of rat calvarial cells. Following a 1 h labeling period with [35S]methionine or [35SO4], radiolabeled BSP was rapidly lost from the cells and appeared transiently in the culture medium and in a 4 M GuHCl extract (G1) of the mineralized tissue. Coinciding with the loss of BSP from these compartments, radiolabeled BSP increased in demineralizing, 0.5 M EDTA extracts (E) of the bone, in a subsequent GuHCl extract (G2), and in a bacterial collagenase digest (CD fraction) of the extracted tissue, over a 24 h chase period. In comparison, the 55 kDa form of OPN, with a small amount of the 44 kDa OPN, was secreted almost entirely into the culture medium. Most of the 44 kDa OPN, together with some 55 kDa OPN, accumulated rapidly in the E extract but could not be detected in either G extract or in the CD fraction. SPARC appeared transiently in the G1 extract, but was otherwise quantitatively secreted into the culture medium from where it was lost by complexing and/or degradation. When cultures were continuously labeled over a 12 day period with [35S]methionine, radiolabeled BSP and 44 kDa OPN accumulated in the E extract together with a small amount of SPARC. Some radiolabeled BSP also accumulated in the G2 extract. From the relative incorporation of [35SO4] over the same time period, a time-dependent loss in sulphate from the BSP was evident. Using a 24 h pulse-labeling protocol, the amount of radiolabeled BSP and OPN in the E extract and the BSP in the G2 extract were not altered significantly over a 12-day chase period. These studies demonstrate that the 44 kDa OPN and most of the BSP are rapidly bound to the hydroxyapatite crystals where they may regulate crystal formation and growth during bone formation. Some BSP is deposited in the osteoid and appears to become masked by the formation of hydroxyapatite, indicating a potential role for this protein in epitactic nucleation of hydroxyapatite crystal formation.
Collapse
Affiliation(s)
- S Kasugai
- Medical Research Council Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, Ontario, Canada
| | | | | |
Collapse
|
43
|
Chen J, Shapiro HS, Sodek J. Development expression of bone sialoprotein mRNA in rat mineralized connective tissues. J Bone Miner Res 1992; 7:987-97. [PMID: 1442213 DOI: 10.1002/jbmr.5650070816] [Citation(s) in RCA: 272] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Bone sialoprotein (BSP) is a phosphorylated and sulfated glycoprotein that is a major noncollagenous protein of bone and other mineralizing connective tissues. BSP is characterized by the presence of several polyglutamic acid segments and an RGD motif that mediates cell attachment through a vitronectin-like receptor. Although the precise function of BSP is unknown, the expression of BSP in conjunction with bone formation in vitro indicates a role for this protein in the biomineralization of connective tissues. In this study we used Northern hybridization and in situ hybridization to determine the tissue-specific and developmental expression of BSP during embryogenesis and growth of rat tissues. Analysis of tissues obtained from 13, 17, and 21 day fetuses, and from 4-, 14-, and 100-day-old animals indicates that BSP mRNA expression is restricted to cells actively forming the mineralizing tissues of bone, dentin and cementum. BSP mRNA transcripts were first evident in fully differentiated osteoblasts of 17 day fetal tissues at sites of de novo intramembranous and endochondral bone formation, with maximal expression observed at 21 days of gestation. Thereafter, BSP mRNA levels decreased markedly, and in adult bone hybridization was detected only in the primary spongiosa of long bones. In comparison, mRNAs for osteopontin (OPN), alkaline phosphatase (ALP), and osteocalcin (OC) peaked at 4-14 days postpartum before declining. In the tibiae, Northern hybridization revealed a second peak of mRNA for BSP, ALP, and OPN at 14 days, reflecting an increased osteogenic activity due to the formation of the secondary centers of ossification in the epiphyseal cartilage. In situ hybridization also revealed BSP mRNA in hypertrophic chondrocytes at sites of bone formation, in odontoblasts of the incisor during dentinogenesis, and in cementoblasts during cementogenesis. In view of the restricted distribution and temporal changes in the expression of BSP mRNA that we observed together with the chemical properties of BSP, we believe that this protein has a specific role in mediating the initial stages of connective tissue mineralization.
Collapse
Affiliation(s)
- J Chen
- MRC Group in Periodontal Physiology, Faculty of Dentistry, University of Toronto, Ontario, Canada
| | | | | |
Collapse
|
44
|
Gorski JP. Acidic phosphoproteins from bone matrix: a structural rationalization of their role in biomineralization. Calcif Tissue Int 1992; 50:391-6. [PMID: 1596774 DOI: 10.1007/bf00296767] [Citation(s) in RCA: 174] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Osteopontin, bone sialoprotein, and bone acidic glycoprotein-75 are three acidic phosphoproteins that are isolated from the mineralized phase of bone matrix, are synthesized by osteoblastic cells, and are generally restricted in their distribution to calcified tissues. Although each is a distinct gene product, these proteins share aspartic/glutamic acid contents of 30-36% and each contains multiple phosphoryl and sialyl groups. These properties, plus a strict relationship of acidic macromolecules with cell-controlled mineralization throughout nature, suggest functions in calcium binding and nucleation of calcium hydroxyapatite crystal formation. However, direct proof for such roles is still largely indirect in nature. The purpose of this review is to present two speculative hypotheses regarding acidic phosphoprotein function. The goal was to use new sequence information along with database comparisons to develop a structural rationalization of how these proteins may function in calcium handling by bone. For example, our analysis has identified a conserved polyacidic stretch in all three phosphoproteins which we propose mediates metal binding. Also, conserved motifs were identified that are analogous with those for casein kinase II phosphorylation sites and whose number correlates well with that of phosphoryl groups/protein. A two-state conformational model of calcium binding by bone matrix acidic phosphoproteins is described which incorporates these findings.
Collapse
Affiliation(s)
- J P Gorski
- Division of Molecular Biology and Biochemistry, School of Basic Life Sciences, University of Missouri-Kansas City 64110
| |
Collapse
|
45
|
Abstract
Bone sialoprotein (BSP) is a major bone-related protein. Although a few other tissues contain trace amounts of BSP message, bone cells and bone matrix are the major sources of BSP, suggesting that this protein could be a potential marker of bone metabolism. Purified bovine BSP showed a 70% homology of its first 13 amino acid N-terminal sequence with human BSP and was used to raise antibodies in rabbit and to develop a specific radioimmunoassay (RIA). Using this RIA, we have shown that BSP is present in serum with values in the range of 10-30 ngEq/ml in the serum of normal adults. Values obtained in plasma prepared without platelet activation are about one-half of those in matched sera, suggesting that BSP present in serum is in part derived from platelets during the activation process. Using Western blot and RIA techniques, we confirmed that platelets contain immunoreactive BSP and that the protein is released after thrombin stimulation of these cells. In addition to BSP, platelets contain a 45 kD immunoreactive material that has not been precisely identified. Available evidence indicates that this material is not osteonectin or osteopontin and that it may be a BSP-like protein rather than a degradation product of BSP. Platelets from a patient having a gray platelet syndrome, characterized by a deficiency in platelet alpha-granules and in the alpha-granule secretory proteins, did not show any deficiency of BSP, suggesting that immunoreactive BSP present in platelets is not endogenously synthesized by megakaryocytes but rather originates from plasma by endocytosis.
Collapse
Affiliation(s)
- C Chenu
- INSERM Unité 234, Hôpital Eduard Herriot, Lyon, France
| | | |
Collapse
|
46
|
Farach-Carson MC, Wright GC, Butler WT. Improved binding of acidic bone matrix proteins to cationized filters during solid phase assays. BONE AND MINERAL 1992; 16:1-9. [PMID: 1537006 DOI: 10.1016/0169-6009(92)90818-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A number of commercially available matrix filter supports have been designed for the immobilization of proteins following either electrotransfer from sodium dodecyl sulfate (SDS) polyacrylamide gels or direct application during dot blotting assays. These matrices differ with respect to chemical composition, charge, pore size, and degree of hydrophobicity. It follows that the properties of the protein(s) of interest will greatly influence the degree to which they interact with and ultimately bind to various filters. Acidic bone proteins contain diverse post-translational modifications that influence their interactions with solid phase matrices such as those used in immunoblotting (Western or dot blotting) or ion binding (overlay) procedures. This communication describes the results of a study comparing binding of various mixtures of non-collagenous acidic bone matrix phosphoproteins as well as purified osteopontin and osteocalcin to various filters including nitrocellulose and cationized paper or nylon. Based on our findings, we recommend the use of cationized filters for solid phase assays requiring the binding of these acidic macromolecules to background supports.
Collapse
Affiliation(s)
- M C Farach-Carson
- Department of Biological Chemistry, University of Texas Dental Branch, Houston 77225
| | | | | |
Collapse
|
47
|
Abstract
SPARC/Osteonectin is a major bone-related protein that is also present in nonmineralized tissues and in platelets. As compared to bone SPARC/Osteonectin, SPARC/Osteonectin from platelets presents a slightly lower electrophoretic mobility in SDS-PAGE and a 100-fold decreased affinity for a unique monoclonal antibody, Mab2 (Malaval et al. 1991). To check the tissular diversity of SPARC/Osteonectin, protein extracts from bovine bone, nonmineralized tissues, and platelets were screened by immunoblotting and immunoradiometric assay, with Mab2 and three other monoclonal antibodies recognizing distinct epitopes. The SPARC/Osteonectin secreted by a human osteosarcoma cell line (MG63) was also tested. In all the nonmineralized tissues tested (gut, bone marrow, tendon, mesentery, artera, lens, skin, liver, and cornea), SPARC/Osteonectin presents the same immunoreactivity and electrophoretic mobility as in bone. The heavier molecular weight and Mab2-negative form present in platelets seems to be unique to this cell type. Osteosarcoma cell extracts and conditioned media give the same results as bone extracts, indicating that the low molecular weight and Mab2-positive form of SPARC/Osteonectin present in most tissues does not result from proteolytic cleavage in the matrix, but is secreted as such. Bone and platelet SPARC/Osteonectin present different patterns of sensitivity to glycosidases, suggestive of a difference in N-glycosylation. However, these treatments do not affect the decreased affinity of Mab2 for platelet SPARC/Osteonectin, which is not likely to be related to difference in N-glycosylation.
Collapse
Affiliation(s)
- C Maillard
- Inserm U234, Hopital Edouard Herriot, Lyon, France
| | | | | |
Collapse
|
48
|
Bianco P, Fisher LW, Young MF, Termine JD, Robey PG. Expression of bone sialoprotein (BSP) in developing human tissues. Calcif Tissue Int 1991; 49:421-6. [PMID: 1818768 DOI: 10.1007/bf02555854] [Citation(s) in RCA: 281] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Bone sialoprotein (BSP) and its messenger RNA were localized in developing human skeletal and nonskeletal tissues by means of immunohistochemistry and in situ hybridization. Both protein and mRNA were found in mature, bone-forming cells but not in their immature precursors. In addition, osteoclasts displayed positive immunostaining and high densities of autoradiographic grains by in situ hybridization experiments. BSP was expressed in fetal epiphyseal cartilage cells, particularly in hypertrophic chondrocytes of growth plates. Though neither the protein nor the mRNA were identified in a variety of other connective and nonconnective tissues, an unexpected finding was the expression of BSP in the trophoblast cells of placenta. These findings show that BSP is primarily an osteoblast-derived component of the bone matrix expressed at late stages of differentiation. We have also found that osteoclasts produce BSP, possibly as a mediator of cell attachment to bone.
Collapse
Affiliation(s)
- P Bianco
- Bone Research Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, Maryland 20892
| | | | | | | | | |
Collapse
|
49
|
Ohnishi T, Arakaki N, Nakamura O, Hirono S, Daikuhara Y. Purification, characterization, and studies on biosynthesis of a 59-kDa bone sialic acid-containing protein (BSP) from rat mandible using a monoclonal antibody. Evidence that 59-kDa BSP may be the rat counterpart of human alpha 2-HS glycoprotein and is synthesized by both hepatocytes and osteoblasts. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98733-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
50
|
Boskey AL. The role of extracellular matrix components in dentin mineralization. CRITICAL REVIEWS IN ORAL BIOLOGY AND MEDICINE : AN OFFICIAL PUBLICATION OF THE AMERICAN ASSOCIATION OF ORAL BIOLOGISTS 1991; 2:369-87. [PMID: 1654141 DOI: 10.1177/10454411910020030501] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The extracellular matrix of dentin consists of mineral (hydroxyapatite), collagen, and several noncollagenous matrix proteins. These noncollagenous matrix proteins may be mediators of cell-matrix interactions, matrix maturation, and mineralization. This review describes the current knowledge of the chemistry of mineral crystal formation in dentin with special emphasis on the roles of the dentin matrix proteins. The functions of some of these matrix proteins in the mineralization process have been deduced based on in vitro studies. Functions for others have been postulated based on analogy with some of the bone matrix proteins. Evidence suggests that several of these matrix proteins may have multiple effects on nucleation, crystal growth, and orientation of dentin hydroxyapatite.
Collapse
Affiliation(s)
- A L Boskey
- Laboratory for Ultrastructural Biochemistry, Hospital for Special Surgery, New York, New York
| |
Collapse
|