Study of hexosamine derivatives on osteogenic differentiation of dental pulp stem cells

• Main Authors: Chien-Hsun Huang, 黃建勛
• Other Authors: Tai-Horng Young
• Format: Others
• Language: en_US
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/10341109840024534535

博士 === 國立臺灣大學 === 醫學工程學研究所 === 98 === Adult stem cells are undifferentiated cells, which have the abilities to divide or self-renew indefinitely and generate most cell lineages. Human mesenchymal stem cells (MSCs) are known to be most useful multipotent cells capable of differentiating into various mesenchymal phenotypes, including osteogenic, myogenic, chrondogenic, and adipogenic lineages. Furthermore, MSCs have also been verified that they abound in various tissues and are able to be isolated from skeletal muscle, adipose tissue, umbilical cord, liver, lung, synovium as well as dental pulp. Dental pulp stem cells (DPSCs) are ideal cell source for hard tissue regeneration due to their well clonogenic, self-renewing, and multi-potential capability. In the part I of this study, primary cell cultures were obtained from human dental pulp tissue of developing third molars, and flow cytometry was used to sort the subpopulation of DPSCs with STRO-1 and CD146 double-positive expression (denoted “DPSCs”). It was noted that DPSCs exhibited superior colonogenic potential and osteogenic differentiation capability to the dental pulp cell subpopulation with STRO-1 and CD146 double-negative expression (denoted DPCs). Besides, our recent study first revealed that the higher level of N-acetylglucosaminyltransferase V (GnT-V) resulted in the superior colonogenic and self-renewal potential of DPSCs. Furthermore, the GnT-V catalyzed the production of N-glycan-branching transforming growth factor-β receptor (TGFβr) type I, which subsequently activated Smads signals in DPSCs with various hexosamine derivatives, e.g. glucosamine (GlcN), N-acetyl-d-glucosamine (GlcNAc), d-mannosamine (ManN) and acetyl-d-mannosamine (ManNAc). A low concentration (0.005 mg/ml) of exogenous hexosamine derivatives was effective in promoting the early osteogenic differentiation of DPSCs. By modulating the GnT-V catalyzed N-glycan forming TGF-βr type I and subsequently Smads signal pathways, GlcN/GlcNAc and ManN/ManNAc treated DPSCs phosphorylated the Runt-related transcription factor 2/Core-binding factor alpha1 (Runx2/Cbfa1) and upregulated mRNA levels of Runx2/Cbfa1, alkaline phosphatase (ALP) and osteocalcin (OCN). In the presence of osteogenic supplements, hexosamine-treated DPSCs produced more mineralized-matrix deposition than did the untreated groups. In summary, this study demonstrated that DPSCs exhibited high level of Gnt-V, which resulted in the superior colonogenic and self-renewal potential of DPSCs. The exogenous hexosamine with low molecular weight, such as GlcN/GlcNAc and ManN/ManNAc, facilitated GnT-V catalyzed N-glycan branching glycoprotein on surface, e.g. TGFβr type I, rather than O-linked glycosylation; and increase level of TGFβr type I further regulated the osteogenic differentiation of human DPSCs through Smads signal pathway.