The interaction of sodium trimetaphosphate with collagen I induces conformational change and mineralization that prevents collagenase proteolytic attack

Author(s)

Carvalho, Rafael Guzella ^[1] ; Palacio Alvarez, Marcela Maciel ^[1] ; Oliveira, Thales de Sa ^[2] ; Polassi, Mackeler Ramos ^[2] ; Vilhena, Fabiano Vieira ^[3] ; Alves, Flavio Lopes ^[4] ; Nakaie, Clovis Ryuichi ^[4] ; Nascimento, Fabio Dupart ^[5] ; Perlatti D'Alpino, Paulo Henrique ^[2] ; dos Santos Tersariol, Ivarne Luis ^{[1, 5]}

Affiliation

^[1] Univ Fed Sao Paulo, Dept Biochem, Sao Paulo - Brazil

^[2] Univ Anhanguera Sao Paulo UNIAN SP, Biotechnol & Innovat Hlth Program, Sao Paulo, SP - Brazil

^[3] Trials Oral Hlth & Technol, Sao Paulo, SP - Brazil

^[4] Univ Fed Sao Paulo, Dept Biophys, Escola Paulista Med, Sao Paulo, SP - Brazil

^[5] Univ Mogi das Cruzes, Interdisciplinary Ctr Biochem Invest, Mogi Das Cruzes, SP - Brazil

• Document type: Journal article
• Source: Dental Materials; v. 36, n. 6, p. E184-E193, JUN 2020.
• Web of Science Citations: 0

Abstract

Objectives. This study evaluated the cell viability and expression of different major genes involved in mineralization in odontoblast-like cells exposed to sodium trimetaphosphate (STMP). It was also investigated the influence of STMP on the rate of calcium phosphate crystal growth, its anti-proteolytic action against the enzymatic degradation of type I collagen, the binding mechanism of STMP to collagen fibrils, and the potential mechanism to induce collagen stabilization. Methods. Immortalized rat odontoblast MDPC-23 cells were cultured. Cell viability was assessed by trypan blue staining, and the changes in gene expression balance induced by STMP were assessed by quantitative reverse transcription (qRT) PCR assays. Crystalline particle formation was monitored by light-scattering detectors to estimate pH variation and the radial size of the crystalline particles as a function of reaction time (pH 7.4, 25 degrees C) in the presence of STMP in supersaturated calcium phosphate solution (Ca/P = 1.67). Images were obtained under atomic force microscopy (AFM) to measure the particle size in the presence of STMP. A three-point bending test was used to obtain the elastic modulus of fully demineralized dentin beams after immersion in STMP solution. The binding mechanism of STMP to collagen fibrils and potential stabilization mechanism was assessed with circular dichroism spectrometry (CD). The data were analyzed statistically (alpha = 0.05). Results. STMP had no significant influence on the cell viability and gene expression of the MDPC-23 cells. STMP greatly increased the rate of crystal growth, significantly increasing the average radial crystal size. AFM corroborated the significant increase of STPM-treated crystal size. Mineralized collagen I fibrils exhibited less collagenase degradation with lower STMP concentration. CD analysis demonstrated changes in the conformational stability after STMP binding to type I collagen. Significance. The increased resistance of collagen against the proteolytic activity of collagenases appears to be related to the conformational change induced by STMP binding in collagen I and the STMP capacity for promoting biomimetic mineralization in type I collagen fibrils. (C) 2020 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 13/05822-9 - Proteinase-Activated Receptors (PARs) in the dentin-pulp complex: identification, modulation and signal tranduction in caries disease
• Grantee: Fábio Dupart Nascimento
• Support Opportunities: Research Grants - Young Investigators Grants