Amelogenin Peptide Extract Increases Differentiation and Angiogenic and Local Factor Production and Inhibits Apoptosis in Human Osteoblasts

Zvi Schwartz,Barbara D Boyan,Argelia Almaguer-Flores,Anja C Gemperli,Rene Olivares-Navarrete,Corinna Mauth,Sharon L Hyzy

doi:10.5402/2013/347318

Abstract

Enamel matrix derivative (EMD), a decellularized porcine extracellular matrix (ECM), is used clinically in periodontal tissue regeneration. Amelogenin, EMD’s principal component, spontaneously assembles into nanospheresin vivo, forming an ECM complex that releases proteolytically cleaved peptides. However, the role of amelogenin or amelogenin peptides in mediating osteoblast response to EMD is not clear. Human MG63 osteoblast-like cells or normal human osteoblasts were treated with recombinant human amelogenin or a 5 kDa tyrosine-rich amelogenin peptide (TRAP) isolated from EMD and the effect on osteogenesis, local factor production, and apoptosis assessed. Treated MG63 cells increased alkaline phosphatase specific activity and levels of osteocalcin, osteoprotegerin, prostaglandin E2, and active/latent TGF-β1, an effect sensitive to the effector and concentration. Primary osteoblasts exhibited similar, but less robust, effects. TRAP-rich 5 kDa peptides yielded more mineralization than rhAmelogenin in osteoblastsin vitro. Both amelogenin and 5 kDa peptides protected MG63s from chelerythrine-induced apoptosis. The data suggest that the 5 kDa TRAP-rich sequence is an active amelogenin peptide that regulates osteoblast differentiation and local factor production and prevents osteoblast apoptosis.

Highlights

Enamel matrix derivative (EMD) is a decellularized extracellular matrix (ECM) isolated from porcine tooth germs and has been used clinically in a carrier as Emdogain (Institut Straumann AG, Basel, Switzerland) to promote periodontal tissue regeneration, including periodontal ligament, alveolar bone, and cementum [1,2,3]
MG63 cells treated with Fraction C had higher alkaline phosphatase-specific activity than untreated cells, with the greatest effect seen in cultures treated with 1 μg/mL
In contrast to the four peaks found in the original fractionation [29], here we found that Fraction C contained just two peaks, one of 43 amino acids and the other one corresponding to 45 amino acids in length, which correspond to the previously reported tyrosine-rich amelogenin peptide (TRAP) species [28]

Summary

Introduction

Enamel matrix derivative (EMD) is a decellularized extracellular matrix (ECM) isolated from porcine tooth germs and has been used clinically in a carrier as Emdogain (Institut Straumann AG, Basel, Switzerland) to promote periodontal tissue regeneration, including periodontal ligament, alveolar bone, and cementum [1,2,3]. During tooth formation, enamel matrix proteins are secreted by ameloblasts and Hertwig’s epithelial root sheath. In addition to providing the structural matrix for the developing enamel, these proteins act as mediators at the epithelial/mesenchymal interface, resulting in formation of periodontal ligament, alveolar bone, and dental cementum [5,6,7]. In addition to its effects on periodontal bone formation, EMD has been applied to long bone defects, increasing de novo trabecular bone formation [8]. Amelogenin, a component of EMD [10], has been applied to treat difficult-to-heal venous ulcers, decreasing ulcer area, pain, and exudates [11, 12]

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