Effects of C-xylopyranoside derivative on epithelial regeneration in an in vitro 3D oral mucosa model.

Identifying substandard tissue-engineered oral mucosa grafts with a poor epithelium before clinical use is critical to ensure quality assurance/control in regenerative medicine, leading to success of grafting. This study investigated the effects of one of the C-xylopyranoside derivatives, ß-D-xylopyranoside-n-propane-2-one (XPP), on oral epithelial regeneration. Using a three-dimensional oral mucosa model, we analyzed changes of the epithelial structure, glycosaminoglycan (GAG) synthesis, the expression levels of basement membrane zone markers, and substrates of Akt/mTOR signaling. Compared with the control, 2 mM XPP treatment increased the mean and minimal epithelial thickness, and reduced the variation of epithelial thickness. It also stimulated expressions of decorin and syndecan-1 with change of GAG amount and/or composition, and enhanced the expressions of integrin α6, CD44, and Akt/mTOR signaling substrates. These findings suggest that XPP supplementation contributes to consistent epithelial regeneration. Moreover, upregulation of those markers may play a role in increasing the quality of the oral mucosal epithelium.

Glycosaminoglycan mimetics inhibit SDF-1/CXCL12-mediated migration and invasion of human hepatoma cells.

We have recently reported that the CXC-chemokine stromal cell-derived factor-1 (SDF-1)/CXCL12 induces proliferation, migration, and invasion of the Huh7 human hepatoma cells through its G-protein-coupled receptor CXCR4 and that glycosaminoglycans (GAGs) are involved in these events. Here, we demonstrate by surface plasmon resonance that the chemokine binds to GAG mimetics obtained by grafting carboxylate, sulfate or acetate groups onto a dextran backbone. We also demonstrate that chemically modified dextrans inhibit SDF-1/CXCL12-mediated in vitro chemotaxis and anchorage-independent cell growth in a dose-dependent manner. The binding of GAG mimetics to the chemokine and their effects in modulating the SDF-1/CXCL12 biological activities are mainly related to the presence of sulfate groups. Furthermore, the mRNA expression of enzymes involved in heparan sulfate biosynthesis, such as exostosin-1 and -2 or N-deacetylase N-sulfotransferases remained unchanged, but heparanase mRNA and protein expressions in Huh7 cells were decreased upon GAG mimetic treatment. Moreover, decreasing heparanase-1 mRNA levels by RNA interference significantly reduced SDF-1/CXCL12-induced extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation. Therefore, we suggest that GAG mimetic effects on SDF-1/CXCL12-mediated hepatoma cell chemotaxis may rely on decreased heparanase expression, which impairs SDF-1/CXCL12's signaling. Altogether, these data suggest that GAG mimetics may compete with cellular heparan sulfate chains for the binding to SDF-1/CXCL12 and may affect heparanase expression, leading to reduced SDF-1/CXCL12 mediated in vitro chemotaxis and growth of hepatoma cells.

Glycosaminoglycan mimetics-induced mobilization of hematopoietic progenitors and stem cells into mouse peripheral blood: structure/function insights.

OBJECTIVE: Glycosaminoglycans (GAG) are major components of bone marrow extracellular matrix because they have the property to interact with cells and growth factors in hematopoietic niches. In this study, we investigated the effect of two different chemically defined GAG mimetics on mobilization of hematopoietic stem and progenitor cells (HSPCs) in mice peripheral blood. MATERIALS AND METHODS: Mobilization was achieved by intraperitoneal injection of GAG mimetics. Mobilized cells were characterized phenotypically by reverse transcription polymerase chain reaction and fluorescence-activated cell sorting analysis and functionally by colony-forming cell, cobblestone area-forming cell and long-term culture-initiating cell assays in vitro. Radioprotection assays were performed to confirm the functionality of primitive hematopoietic cells in vivo. Involvement of stromal-derived factor-1 (SDF-1) and matrix metalloproteinase-9 (MMP-9) were investigated. RESULTS: GAG mimetics treatment induces hyperleukocytosis and mobilization of HSPC. They synergize with the effects of granulocyte colony-stimulating factor or AMD3100 on hematopoietic progenitors mobilization. Reconstitution of lethally irradiated recipient mice with peripheral blood mononuclear cells from GAG mimetic-treated donor mice improves engraftment and survival. BiAcore studies indicate that the mimetics interact directly with SDF-1. In addition, GAG mimetics-induced mobilization is associated with increased levels of pro- and active MMP-9 from bone marrow cells and increased level of SDF-1 in peripheral blood. Finally, mobilization is partially inhibited by co-injection with anti-SDF-1 antibody. CONCLUSION: This study demonstrates that GAG mimetics induce efficient mobilization of HSPCs, associated with an activation of pro-MMP-9 and a modification in the SDF-1 concentration gradient between bone marrow and peripheral blood. We suggest that structural features of GAGs can modify the nature of mobilized cells.