Effects of human full-length amelogenin on the proliferation of human mesenchymal stem cells derived from bone marrow

Abstract

Amelogenins are enamel matrix proteins that play a crucial role in enamel formation. Recent studies have revealed that amelogenins also have cell signaling properties. Although amelogenins had been described as specific products of ameloblasts, recent research has demonstrated their expression in bone marrow stromal cells. In this study, we examined the effect of recombinant human full-length amelogenin (rh174) on the proliferation of human mesenchymal stem cells (MSCs) derived from bone marrow and characterized the associated changes in intracellular signaling pathways. MSCs were treated with rh174 ranging in dose from 0 to 1,000 ng/ml. Cell proliferative activity was analyzed by bromodeoxyuridine (BrdU) immunoassay. The expression of lysosomal-associated membrane protein 1 (LAMP1), a possible amelogenin receptor, in MSCs was analyzed. Anti-LAMP1 antibody was used to block the binding of rh174 to LAMP1. The MAPK-ERK pathway was examined by Cellular Activation of Signaling ELISA (CASE) kit and western blot analysis. A specific MAPK inhibitor, U0126, was used to block ERK activity. It was shown that rh174 increased the proliferation of MSCs and MAPK-ERK activity. The MSC proliferation and MAPK-ERK activity enhanced by rh174 were reduced by the addition of anti-LAMP1 antibody. Additionally, the increased proliferation of MSCs induced by rh174 was inhibited in the presence of U0126. In conclusion, it is demonstrated that rh174 increases the proliferation of MSCs by interaction with LAMP1 through the MAPK-ERK signaling pathway, indicating the possibility of MSC application to tissue regeneration in the orofacial region.

Tracking Endogenous Amelogenin and Ameloblastin In Vivo

“…Disturbed EMP expression patterns are associated with alveolar and jaw bone malformations [33], [34]. These findings and the present data suggest that solubilized EMPs may play a role in controlling cell fate through short-distance paracrine and autocrine functions and thus control local bone morphology via signals previously evidenced for AMBN [19], [53], [54] and AMELX [55], [56]. We thus propose a model in which EMPs play a role in mandibular physiology (Fig.…”

Expression and Function of Enamel-related Gene Products in Calvarial Development

“…Together, these findings illustrate that both Amel and Ambn ERPs exhibit highly visible effects on bone matrix mineralization and bone marker gene expression. The concept that ERPs are involved in osteoblast differentiation or bone matrix mineralization is supported by several previous studies related to the role of Amel in the modulation of mineralized tissue homeostasis, including activation of osteoclastogenesis (Hatakeyama et al, 2006), modulation of cementogenesis (Swanson et al, 2006), and bone marrow stem cell proliferation (Huang et al, 2010). Recent studies suggested that Ambn binds CD63 and may act through integrin β1 and C Src kinase inhibition to promote osteogenic differentiation (Iizuka et al, 2011;Zhang et al, 2011).…”

The Effects of Synthetic Oligopeptide Derived from Enamel Matrix Derivative on Cell Proliferation and Osteoblastic Differentiation of Human Mesenchymal Stem Cells

“…It has been suggested that EMD and the other amelogenin peptides can regulate cellular functions through the ERK 1/2 signaling pathway [41,42]. We speculated that cell proliferation and osteoblastic differentiation of human MSCs are regulated by the ERK 1/2 signaling pathway as well as EMD.…”

“…Therefore, using the ERK 1/2 inhibitor, PD98059, we examined the molecular mechanism by which SP affects cell proliferation and osteoblastic differentiation in human MSCs. The concentration of the inhibitor (10 µM) was set according to a previous report [41]. As shown in Figure 5, Figure 6, Figure 7 and Figure 8, the inhibitor significantly suppressed cell proliferation and osteoblastic differentiation induced by SP.…”