Bioactive nanofibers instruct cells to proliferate and differentiate during enamel regeneration

Zhan Huang, Timothy D. Sargeant, James F. Hulvat, Alvaro Mata, Pablo Bringas, Chung Yan Koh, Samuel I. Stupp, Malcolm L. Snead

Research output: Contribution to journalArticle

95 Citations (Scopus)

Abstract

During tooth development, ectoderm-derived ameloblast cells create enamel by synthesizing a complex protein mixture serving to control cell to matrix interactions and the habit of hydroxyapatite crystallites. Using an in vitro cell and organ culture system, we studied the effect of artificial bioactive nanostructures on ameloblasts with the long-term goal of developing cell-based strategies for tooth regeneration. We used branched peptide amphiphile molecules containing the peptide motif Arg-Gly-Asp, or "RGD" (abbreviated BRGD-PA), known to self-assemble in physiologic environments into nanofibers that display on their surfaces high densities of this biological signal. Ameloblast-like cells (line LS8) and primary enamel organ epithelial (EOE) cells were cultured within PA hydrogels, and the PA was injected into the enamel organ epithelia of mouse embryonic incisors. The expression of amelogenin, ameloblastin, integrin α5, and integrin α6 was detected by quantitative real-time PCR and immunodetection techniques. We performed cell proliferation assay using BrdU labeling and a biomineralization assay using Alizarin red S staining with quantitative Ca2+ measurements. In the cell culture model, ameloblast-like cells (L58) and primary EOE cells responded to the BRGD-PA nanostructures with enhanced proliferation and greater amelogenin, ameloblastin, and integrin expression levels. At the site of injection of the BRGD-PA in the organ culture model, we observed EOE cell proliferation with differentiation into ameloblasts as evidenced by their expression of enamel specific proteins. Ultrastructural analysis showed the nanofibers within the forming extracellular matrix, in contact with the EOE cells engaged in enamel formation and regeneration. This study shows that BRGD-PA nanofibers present with enamel proteins participate in integrin-mediated cell binding to the matrix with delivery of instructive signals for enamel formation.

Original languageEnglish
Pages (from-to)1995-2006
Number of pages12
JournalJournal of Bone and Mineral Research
Volume23
Issue number12
DOIs
Publication statusPublished - Dec 1 2008

Keywords

  • Ameloblastin
  • Amelogenin
  • Enamel extracellular matrix
  • Enamel organ epithelium
  • Integrins
  • Peptide amphiphiles
  • Regeneration

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Orthopedics and Sports Medicine

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  • Cite this

    Huang, Z., Sargeant, T. D., Hulvat, J. F., Mata, A., Bringas, P., Koh, C. Y., Stupp, S. I., & Snead, M. L. (2008). Bioactive nanofibers instruct cells to proliferate and differentiate during enamel regeneration. Journal of Bone and Mineral Research, 23(12), 1995-2006. https://doi.org/10.1359/jbmr.080705