This competing renewal continues to be based on the need for design and development of new biomaterials that will be utilized in repair of defective tooth enamel affected by genetic or environmental factors. We will focus on the study of fundamental chemical and biological principles of organic matrix assembly, disassembly, degradation, and control of mineral nucleation and growth in enamel biomineralization. We will continue developing biomimetic strategies for the synthesis of enamel-like material. We hypothesize that the highly organized carbonated hydroxyapatite crystals in enamel continuously grow by means of complex protein- protein, protein-proteinase, and protein-mineral interactions that are primarily controlled by the formation of a broad range of quaternary structures of amelogenin undergoing proteolytic possessing and interacting with non-amelogenins. We further hypothesize that functional enamel-like material can be prepared in a cell-free system by using a chitosan-amelogenin as the basic structural framework and incorporating principles that we have learned and are continuing to learn from our in vitro and in vivo studies. We propose:
Aim I. To investigate amelogenin-enamelin interactions at a nanoscale level in vitro and in vivo. To study the dynamics of calcium phosphate mineralization events at a nanoscale level when enamelin is combined with amelogenin, using high resolution in situ atomic force (AFM) and in situ transmission electron microscopy (TEM).
Aim II. To determine the amount of protein occluded inside synthetic crystals before and after C-terminal cleavage of amelogenin as well as in enamel crystals isolated from Mmp-20 knock-out animals. To investigate the dynamics of postnucleation mineralization events at a nanoscale level during Mmp-20 proteolysis of amelogenin, using high resolution in situ AFM and TEM.
Aim III. To apply chitosan-based hydrogels as mineralization matrices in the development of biomimetic strategies for re-growth of a functional enamel-like material that could be used in the clinical setting to halt incipient carious lesions. Elucidating the dynamic interactions of enamelin and Mmp-20 with amelogenin proposed in aims I- II will contribute to our understanding of the structural biology and function of the enamel extracellular matrix in vivo, and will provide a soli ground for the design and development of improved dental materials (aim III). Moreover, this study will have a significant impact on the field of biomineralization, macromolecular self-assembly, protein structure, and the understanding of pathological enamel formation.

Public Health Relevance

Despite its significant resistant to fracture and wear tooth enamel can be damaged by caries, erosion, and other genetic and environmental diseases. Because enamel does not regenerate itself, efforts to develop improved biomaterials with mechanical and esthetic attributes close to those of natural enamel is timely and justified. We propose that enamel-inspired biomaterials could be developed as a future generation of dental restorative material. The new biomaterials will have highly ordered mineral micro architecture, and these apatitic materials will fuse readily with existing enamel mineral surfaces.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
2R01DE013414-10A1
Application #
8597305
Study Section
Special Emphasis Panel (ZRG1-MOSS-F (02))
Program Officer
Lumelsky, Nadya L
Project Start
1999-12-01
Project End
2017-05-31
Budget Start
2013-06-14
Budget End
2014-05-31
Support Year
10
Fiscal Year
2013
Total Cost
$401,067
Indirect Cost
$128,000
Name
University of Southern California
Department
Dentistry
Type
Schools of Dentistry
DUNS #
072933393
City
Los Angeles
State
CA
Country
United States
Zip Code
90089
Ruan, Qichao; Siddiqah, Nadia; Li, Xiaochen et al. (2014) Amelogenin-chitosan matrix for human enamel regrowth: effects of viscosity and supersaturation degree. Connect Tissue Res 55 Suppl 1:150-4
Chandrababu, Karthik Balakrishna; Dutta, Kaushik; Lokappa, Sowmya Bekshe et al. (2014) Structural adaptation of tooth enamel protein amelogenin in the presence of SDS micelles. Biopolymers 101:525-35
Ruan, Qichao; Moradian-Oldak, Janet (2014) Development of amelogenin-chitosan hydrogel for in vitro enamel regrowth with a dense interface. J Vis Exp :
Ruan, Qichao; Zhang, Yuzheng; Yang, Xiudong et al. (2013) An amelogenin-chitosan matrix promotes assembly of an enamel-like layer with a dense interface. Acta Biomater 9:7289-97
Gallon, Victoria; Chen, Lisha; Yang, Xiudong et al. (2013) Localization and quantitative co-localization of enamelin with amelogenin. J Struct Biol 183:239-49
Lacruz, Rodrigo S; Lakshminarayanan, Rajamani; Bromley, Keith M et al. (2011) Structural analysis of a repetitive protein sequence motif in strepsirrhine primate amelogenin. PLoS One 6:e18028
Chen, Chun-Long; Bromley, Keith M; Moradian-Oldak, Janet et al. (2011) In situ AFM study of amelogenin assembly and disassembly dynamics on charged surfaces provides insights on matrix protein self-assembly. J Am Chem Soc 133:17406-13
Yang, Xiudong; Sun, Zhi; Ma, Ruiwen et al. (2011) Amelogenin "nanorods" formation during proteolysis by Mmp-20. J Struct Biol 176:220-8
Fan, Yuwei; Nelson, James R; Alvarez, Jason R et al. (2011) Amelogenin-assisted ex vivo remineralization of human enamel: Effects of supersaturation degree and fluoride concentration. Acta Biomater 7:2293-302
Bromley, Keith M; Lakshminarayanan, Rajamani; Lei, Ya-Ping et al. (2011) Folding, assembly, and aggregation of recombinant murine amelogenins with T21I and P41T point mutations. Cells Tissues Organs 194:284-90

Showing the most recent 10 out of 45 publications