9. Non-Collagenous Bone Proteins and Their Role in Substrate-Induced Bioactivity

Sodek, Jaro; Zhang, Q.; Goldberg, Harvey A.; Domenicucci, Carmelo; Kasugai, Shohei; Wrana, Jeffrey L.; Shapiro, Herbert; Chen, J.

doi:10.3138/9781442671508-012

Cited by 26 publications

(32 citation statements)

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“…For recombinant proteins, E. coli strain BL21(DE3) cells were transformed with the expression plasmids described above and grown in PO 4 -buffered Super Broth (SB) supplemented with 15 g/ml kanamycin and 0.4% glucose to an A 600 of 0.6 -0.9. After induction with 2 mM isopropyl-␤-D-thiogalactopyranoside, cultures were grown for a further 4 h. The bacterial cells were then fractionated by sonication in denaturing binding buffer (5 mM imidazole, 0.5 M NaCl, 0.02 M Tris/HCl, 6 M urea, pH 7.9).…”

Section: Methodsmentioning

confidence: 99%

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Delineation of the Hydroxyapatite-nucleating Domains of Bone Sialoprotein

Tye

Rattray

Warner

et al. 2003

Journal of Biological Chemistry

196

181

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Bone sialoprotein (BSP) is a highly modified, anionic phosphoprotein that is expressed almost exclusively in mineralizing connective tissues and has been shown to be a potent nucleator of hydroxyapatite (HA). Two polyglutamic acid (poly[E]) regions, predicted to be in an ␣-helical conformation and located in the amino-terminal half of the molecule, are believed to be responsible for this activity. Using a prokaryotic expression system, full-length rat BSP was expressed and tested for HA nucleating activity in a steady-state agarose gel system. The unmodified protein is less potent than native bone BSP, indicating a role for the post-translational modifications in HA nucleation. domains, were expressed and tested for nucleating activity. Whereas the peptide encompassing the second poly[E] domain was capable of nucleating HA, the first domain peptide showed no activity. The conformation of the wild-type and mutated proteins and peptides were studied by circular dichroism and small angle x-ray scattering, and no secondary structure was evident. These results demonstrate that a sequence of at least eight contiguous glutamic acid residues is required for the nucleation of HA by BSP and that this nucleating "site" is not ␣-helical in conformation.Mineralization of the extracellular matrix in bone, dentin, and cementum is a complex, poorly understood process that is believed to involve both hydroxyapatite-nucleating and -modulating noncollagenous proteins. In bone, it has been postulated that type I collagen acts as a structural matrix, whereas HA nucleation is mediated by an anionic phosphoprotein (1-3). Of the noncollagenous proteins, bone sialoprotein (BSP) 1 is the most likely candidate. The highly anionic nature of BSP and its spatio-temporal pattern of expression have led investigators to propose a role of this protein in the mineralization of bone (1-4).Mammalian BSPs contain an average of 327 amino acids, which includes a 16-residue signal sequence. The protein has a molecular mass of ϳ33-34 kDa. However, post-translational modifications, including both N-and O-linked glycosylation, tyrosine sulfation, and serine and threonine phosphorylation, constitute 50% of the total mature protein weight of ϳ75 kDa. Analysis of the mammalian BSP cDNAs reveals a 45% level of sequence identity, plus an additional 10 -23% in conservative replacements. However, identity of up to 90% is observed in and around two polyglutamic acid sequences (poly[E]); an ArgGly-Asp (RGD) cell-binding motif; sites of phosphorylation, sulfation, and glycosylation; and sequences near the amino and carboxyl termini, which are rich in tyrosine residues (5).Normally BSP expression is limited almost exclusively to mineralized connective tissues, and its expression is localized to areas of bone formation. By in situ hybridization, it has been shown that BSP expression occurs in osteoblasts actively engaged in bone formation and is found at low or undetectable levels in other regions of mineralized tissue (6 -11). Transfection of BSP into nonmineralizin...

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Section: Methodsmentioning

confidence: 99%

“…Of the noncollagenous proteins, bone sialoprotein (BSP) 1 is the most likely candidate. The highly anionic nature of BSP and its spatio-temporal pattern of expression have led investigators to propose a role of this protein in the mineralization of bone (1)(2)(3)(4).…”

mentioning

confidence: 99%

Delineation of the Hydroxyapatite-nucleating Domains of Bone Sialoprotein

Tye

Rattray

Warner

et al. 2003

Journal of Biological Chemistry

196

181

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“…Although osteopontin and BSP do not appear to be evolutionarily related, they have similar amino acid compositions and post-transcriptional modifications. However, BSP contains more sialic acid and sulfate, whereas osteopontin contains more phosphate (5).…”

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confidence: 99%

“…The means by which bone mineralization is achieved is not understood, but several authors have suggested that HA could be nucleated by a complex composed of a polyanionic protein, probably a phosphoprotein, and the large highly ordered fibrils oftype I collagen (1-4). The major phosphoproteins of mammalian bone are bone sialoprotein (BSP) and osteopontin (5). Both are phosphorylated sialoproteins containing tyrosine sulfates, regions enriched in acidic amino acids, and an Arg-Gly-Asp cell attachment sequence.…”

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confidence: 99%

Nucleation of hydroxyapatite by bone sialoprotein.

Hunter

Goldberg

1993

Proc. Natl. Acad. Sci. U.S.A.

608

407

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Bone sdaloprotein (BSP) and osteopontin, the major phosphorylated proteins of mammalin bone, have been proposed to finctIon in the initiation of mineralization. To test this hypothes, the effects ofBSP and osteopontin on hydroxyaatite crystdal formation were determied by usig a steadystate agarose gel system. At low calcium phosphate concentrations, no accmulatio of calcium and phosphate ocurred in control gels or gels cotinin osteopontin. Gels containing BSP at 1-5 pg/mn, however, exhibited a vidble precipitation band and sg ay elevated Ca + P04 contents. By powder x-ray diffrcion, the precipitate formed in the presence of BSP was shown to be hydroxyapatite. These ings es that bone ialoprotein may be involved in the nucleation of hydroxyapatite at the mineralzation front of bone.The mineralization of bone occurs by deposition of carbonated hydroxyapatite (HA) crystals in an extracellular matrix consisting of type I collagen and a variety of noncollagenous proteins. The means by which bone mineralization is achieved is not understood, but several authors have suggested that HA could be nucleated by a complex composed of a polyanionic protein, probably a phosphoprotein, and the large highly ordered fibrils oftype I collagen (1-4). The major phosphoproteins of mammalian bone are bone sialoprotein (BSP) and osteopontin (5). Both are phosphorylated sialoproteins containing tyrosine sulfates, regions enriched in acidic amino acids, and an Arg-Gly-Asp cell attachment sequence. Although osteopontin and BSP do not appear to be evolutionarily related, they have similar amino acid compositions and post-transcriptional modifications. However, BSP contains more sialic acid and sulfate, whereas osteopontin contains more phosphate (5).These proteins also differ in their biological properties. By immunocytochemistry, in situ hybridization, and Northern blotting, it has been shown that osteopontin is expressed at high levels in mineralized connective tissues but also at lower levels in other tissues, including kidney, nervous tissue, and uterus; BSP, in contrast, is specific to mineralized tissues (6-8). During embryogenesis, BSP is first expressed at the onset of bone formation, whereas osteopontin expression is a later event (7). In mineralizingbone cell and organ cultures, BSP associates with the osteoid matrix, whereas osteopontin is released into the culture medium (9, 10). For these reasons, Sodek and coworkers (7) have suggested that BSP is a strong candidate for a role in mineral nucleation.In the present study, the effects of BSP and osteopontin on HA formation have been studied by using a steady-state agarose gel system. METHODSPurfication of BSP and Osteopontin from Porcine Calvaria.BSP and osteopontin were purified from adult porcine cal- varia by fast protein liquid chromatography using ionexchange, HA, and gel-fltration columns as previously described (11). The identity and purity of the protein preparations used were ascertained by gel electrophoresis, Western blotting using affimity-purified antibodies,...

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“…Compared to FM-HA, RN-HA was proved to enhance the osteoblastic differentiation of WJCs, the synthesis of intracellular proteins, the alkaline phosphatase activity and the deposition of calcium-containing mineral, thus enhancing the bonding of orthopedic/dental implants to juxtaposed bone and improving the overall implant efficacy [25,26]. Finally, at the molecular level, OPN, OCN and Runx2 were demonstrated to be expressed during the later extracellular-matrix mineralization [27][28][29][30][31][32][33]. RT-PCR revealed that the expression of OPN and OCN had no clear difference between the two groups.…”

Section: Discussionmentioning

confidence: 99%

Biocompatibility of nano-hydroxyapatite/Mg-Zn-Ca alloy composite scaffolds to human umbilical cord mesenchymal stem cells from Wharton’s jelly in vitro

Guan

Shan

Shi

et al. 2014

Sci. China Life Sci.

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Seeding cells and scaffolds play pivotal roles in bone tissue engineering and regenerative medicine. Wharton's jelly-derived mesenchymal stem cells (WJCs) from human umbilical cord represent attractive and promising seeding cells in tissue regeneration and engineering for treatment applications. This study was carried out to explore the biocompatibility of scaffolds to seeding cells in vitro. Rod-like nano-hydroxyapatite (RN-HA) and flake-like micro-hydroxyapatite (FM-HA) coatings were prepared on Mg-Zn-Ca alloy substrates using micro-arc oxidation and electrochemical deposition. WJCs were utilized to investigate the cellular biocompatibility of Mg-Zn-Ca alloys after different surface modifications by observing the cell adhesion, morphology, proliferation, and osteoblastic differentiation. The in vitro results indicated that the RN-HA coating group was more suitable for cell proliferation and cell osteoblastic differentiation than the FM-HA group, demonstrating better biocompatibility. Our results suggested that the RN-HA coating on Mg-Zn-Ca alloy substrates might be of great potential in bone tissue engineering.nano-hydroxyapatite, Mg-Zn-Ca alloy, mesenchymal stem cells, Wharton's jelly, biocompatibility Citation:Guan FX, Ma SS, Shi XY, Ma X, Chi LK, Liang S, Cui YB, Wang ZB, Yao N, Guan SK, Yang B. Biocompatibility of nano-hydroxyapatite/ Mg-Zn-Ca alloy composite scaffolds to human umbilical cord mesenchymal stem cells from Wharton's jelly in vitro.

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9. Non-Collagenous Bone Proteins and Their Role in Substrate-Induced Bioactivity

Cited by 26 publications

References 0 publications

Delineation of the Hydroxyapatite-nucleating Domains of Bone Sialoprotein

Delineation of the Hydroxyapatite-nucleating Domains of Bone Sialoprotein

Nucleation of hydroxyapatite by bone sialoprotein.

Biocompatibility of nano-hydroxyapatite/Mg-Zn-Ca alloy composite scaffolds to human umbilical cord mesenchymal stem cells from Wharton’s jelly in vitro

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