A novel hydroxyapatite-binding antimicrobial peptide phosphoserine-histatin 5 for caries prevention

Abstract

Objectives: There are many prevention strategies for dental caries including inhibition of cariogenic bacteria and biomineralization. The objective of this study is to synthesize a novel antimicrobial peptide (AMP) phosphoserine-histatin 5 (Sp-H5) with antibacterial activity, hydroxyapatite (HA)-binding ability and remineralization ability by modifying an original endogenous AMP H5. Methods: Molecular dynamics (MD) simulation was used to predict and analyze binding mechanism between Sp-H5 and HA, and interaction mechanism between Sp-H5-HA complex and ions in the remineralization environment. In vitro study, the antibacterial activity and antibacterial adhesion ability of Sp-H5 were investigated; the adsorption ability of Sp-H5 onto HA was evaluated by Micro BCA method; and the remineralization property of Sp-H5 was evaluated by inductively coupled plasma optical emission spectrometry (ICP-OES) and field-emission scanning electron microscope (FE-SEM). Cytocompatibility test was used to identify the safety of Sp-H5. Results: MD simulation revealed that Sp-H5 could adsorb onto HA surface through the electrostatic attraction force of positively charged amino acid residues (Lys12, Arg13, Lys14, Lys18 and Arg23) of Sp-H5 with negatively charged PO43- of HA, and Sp-H5-HA complex would attract more Ca2+ from the remineralization environment. In vitro study, Sp-H5 had similar antibacterial activity and antibacterial adhesion ability as H5. In comparison with H5, Sp-H5 had higher adsorption capacity with HA (Pp-H5 both revealed stronger ability of Ca2+ gain (ICP-OES evaluation, Pp-H5 was also proved to have no adverse effects on the proliferation of human gingival fibroblasts. Conclusions: Sp-H5 is a dual bioactive molecule with antibacterial activity and ability to promote remineralization, for preventing dental caries and realizing in situ self-healing of tooth surface decay.