Enhancing Collagen Mineralization with Amelogenin Peptide: Toward the Restoration of Dentin

The interactions of the ECM (extracellular matrix) protein asporin with ECM components have previously not been investigated. Here, we show that asporin binds collagen type I. This binding is inhibited by recombinant asporin fragment LRR (leucine-rich repeat) 10–12 and by full-length decorin, but not by biglycan. We demonstrate that the polyaspartate domain binds calcium and regulates hydroxyapatite formation in vitro. In the presence of asporin, the number of collagen nodules, and mRNA of osteoblastic markers Osterix and Runx2, were increased. Moreover, decorin or the collagen-binding asporin fragment LRR 10–12 inhibited the pro-osteoblastic activity of full-length asporin. Our results suggest that asporin and decorin compete for binding to collagen and that the polyaspartate in asporin directly regulates collagen mineralization. Therefore asporin has a role in osteoblast-driven collagen biomineralization activity. We also show that asporin can be expressed in Escherichia coli (Rosetta-gami™) with correctly positioned cysteine bridges, and a similar system can possibly be used for the expression of other SLRPs (small LRR proteoglycans/proteins).

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Extracellular Matrix Control of Collagen Mineralization In Vitro

Advanced Functional Materials ◽

10.1002/adfm.201203760 ◽

2013 ◽

Vol 23 (39) ◽

pp. 4906-4912 ◽

Cited By ~ 26

Author(s):

Alexander J. Lausch ◽

Bryan D. Quan ◽

Jason W. Miklas ◽

Eli D. Sone

Keyword(s):

Extracellular Matrix ◽

Collagen Mineralization ◽

Matrix Control

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Biomimetic analogs/bioactive phosphates based adhesives promote dentin collagen mineralization

Dental Materials ◽

10.1016/j.dental.2016.08.119 ◽

2016 ◽

Vol 32 ◽

pp. e57-e58

Author(s):

M.A.C. Sinhoreti ◽

E.F. Soares ◽

G.F. Abuna ◽

J.F. Roulet ◽

S. Geraldeli

Keyword(s):

Collagen Mineralization ◽

Dentin Collagen

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Chemistry of collagen cross-linking: biochemical changes in collagen during the partial mineralization of turkey leg tendon

Biochemical Journal ◽

10.1042/bj3220535 ◽

1997 ◽

Vol 322 (2) ◽

pp. 535-542 ◽

Cited By ~ 73

Author(s):

Lynda KNOTT ◽

John F. TARLTON ◽

Allen J. BAILEY

Keyword(s):

Collagen Matrix ◽

Cross Linking ◽

Cross Link ◽

Lysine Residues ◽

Collagen Mineralization ◽

Cross Links ◽

The Cross ◽

Calcified Tissues ◽

Turkey Leg Tendon ◽

Collagen Cross Linking

With age, the proximal sections of turkey leg tendons become calcified, and this phenomenon has led to their use as a model for collagen mineralization. Mineralizing turkey leg tendon was used in this study to characterize further the composition and cross-linking of collagen in calcified tissues. The cross-link profiles of mineralizing collagen are significantly different from those of other collagenous matrices with characteristically low amounts of hydroxylysyl-pyridinoline and the presence of lysyl-pyridinoline and pyrrolic cross-links. However, the presence of the immature cross-link precursors previously reported in calcifying tissues was not supported in the present study, and was found to be due to the decalcification procedure using EDTA. Analysis of tendons from young birds demonstrated differences in the cross-link profile which indicated a higher level of hydroxylation of specific triple-helical lysines involved in cross-linking of the proximal tendon. This may be related to later calcification, suggesting that this part of the tendon is predestined to be calcified. The minimal changes in lysyl hydroxylation in both regions of the tendon with age were in contrast with the large changes in the cross-link profile, indicating differential hydroxylation of the helical and telopeptide lysine residues. Changes with age in the collagen matrix, its turnover and thermal properties in both the proximal and distal sections of the tendon clearly demonstrate that a new and modified matrix is formed throughout the tendon, and that a different type of matrix is formed at each site.

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On the Collagen Mineralization. A Review

Medicine and Pharmacy Reports ◽

10.15386/cjmed-359 ◽

2015 ◽

Vol 88 (1) ◽

pp. 15-22 ◽

Cited By ~ 12

Author(s):

Gheorghe Tomoaia ◽

Roxana-Diana Pasca

Keyword(s):

Thermal Analysis ◽

Body Fluid ◽

Mineral Content ◽

Biological Properties ◽

Natural Bone ◽

The Past ◽

Investigation Methods ◽

Collagen Mineralization

Collagen mineralization (CM) is a challenging process that has received a lot of attention in the past years. Among the reasons for this interest, the key role is the importance of collagen and hydroxyapatite in natural bone, as major constituents. Different protocols of mineralization have been developed, specially using simulated body fluid (SBF) and many methods have been used to characterize the systems obtained, starting with methods of determining the mineral content (XRD, FTIR, Raman, High-Resolution Spectral Ultrasound Imaging), continuing with imaging methods (AFM, TEM, SEM, Fluorescence Microscopy), thermal analysis (DSC and TGA), evaluation of the mechanical and biological properties, including statistical methods and molecular modeling. In spite of the great number of studies regarding collagen mineralization, its mechanism, both in vivo and in vitro, is not completely understood. Some of the methods used in vitro and investigation methods are reviewed here.

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Glycosaminoglycans accelerate biomimetic collagen mineralization in a tissue-based in vitro model

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1914899117 ◽

2020 ◽

Vol 117 (23) ◽

pp. 12636-12642 ◽

Cited By ~ 1

Author(s):

Magdalena Wojtas ◽

Alexander J. Lausch ◽

Eli D. Sone

Keyword(s):

Protein Content ◽

Periodontal Ligament ◽

In Vitro Model ◽

Enzymatic Digestion ◽

Dental Tissues ◽

Mineralized Tissues ◽

Collagen Mineralization ◽

Vitro Model

Mammalian teeth are attached to the jawbone through an exquisitely controlled mineralization process: unmineralized collagen fibers of the periodontal ligament anchor directly into the outer layer of adjoining mineralized tissues (cementum and bone). The sharp interface between mineralized and nonmineralized collagenous tissues makes this an excellent model to study the mechanisms by which extracellular matrix macromolecules control collagen mineralization. While acidic phosphoproteins, localized in the mineralized tissues, play key roles in control of mineralization, the role of glycosaminoglycans (GAGs) is less clear. As several proteoglycans are found only in the periodontal ligament, it has been hypothesized that these inhibit mineralization of collagen in this tissue. Here we used an in vitro model based on remineralization of mouse dental tissues to determine the role of matrix GAGs in control of mineralization. GAGs were selectively removed from demineralized mouse periodontal sections via enzymatic digestion. Proteomic analysis confirmed that enzymatic GAG removal does not significantly alter protein content. Analysis of remineralized tissue sections by transmission electron microscopy (TEM) shows that GAG removal reduced the rate of remineralization in mineralized tissues compared to the untreated control, while the ligament remained unmineralized. Protein removal with trypsin also reduced the rate of mineralization, but to a lesser extent than GAG removal, despite a much larger effect on protein content. These results indicate that GAGs promote mineralization in mineralized dental tissues rather than inhibiting mineral formation in the ligament, which may have broader implications for understanding control of collagen mineralization in connective tissues.

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