Comparative Analysis of Amelogenin-Derived Peptides LRAP and SP on Osteogenic Differentiation of Human Dental Pulp and Bone Marrow-Derived Stem Cells

TL;DR

This study compares two amelogenin-derived peptides on their ability to promote bone-like cell development in dental and bone marrow stem cells.

Contribution

The study reveals distinct signaling mechanisms of LRAP and SP in promoting osteogenic differentiation in different stem cell types.

Findings

LRAP and SP increased ALP activity and mineral deposition in both hDPSCs and hBMSCs at 10 ng/mL.

LRAP significantly upregulated osteogenic and odontogenic gene expression in hDPSCs.

LRAP induced nuclear β-catenin translocation in hDPSCs, while SP caused membrane-associated accumulation in hBMSCs.

Abstract

Background/Objectives: This study aimed to compare the biological effects of two amelogenin-derived peptides—the leucine-rich amelogenin peptide (LRAP) and a synthetic peptide (SP)—on human dental pulp stem cells (hDPSCs) and human bone marrow–derived mesenchymal stem cells (hBMSCs). The investigation focused on cell viability, osteogenic differentiation, mineralization, gene expression, and β-catenin expression. Methods: hDPSCs and hBMSCs were cultured in osteogenic medium and treated with LRAP and SP at 1, 5, 10, 50, and 100 ng/mL. Cytotoxicity was assessed by MTT assay, while osteogenic differentiation was evaluated by alkaline phosphatase (ALP) activity and Alizarin Red S staining. Gene expression of RUNX2, COL1A1, OCN, MEPE, and DMP1 was quantified by qPCR. β-catenin localization was analyzed by immunofluorescence. Statistical analysis was performed using one-way ANOVA with Tukey’s post hoc test (p < 0.05). Results: Both peptides exhibited good biocompatibility with hBMSCs, while high concentrations (≥50 ng/mL) reduced hDPSC viability. In both cell types, LRAP and SP increased ALP activity and mineral deposition in a concentration-dependent manner, with the greatest effects at 10 ng/mL. LRAP significantly upregulated osteogenic (RUNX2, COL1A1, OCN) and odontogenic (MEPE, DMP1) gene expression in hDPSCs. Immunofluorescence revealed nuclear β-catenin translocation in hDPSCs and membrane-associated accumulation in hBMSCs, indicating activation of canonical and non-canonical pathways, respectively. Conclusions: LRAP and SP promote osteogenic differentiation through distinct cell-type-specific signaling mechanisms, highlighting their potential as biomimetic agents for mineralized tissue regeneration.

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