Piyarat Chansiripornchai

A feasibility study of an in vitro differentiation potential toward insulin-producing cells by dental tissue-derived mesenchymal stem cells

Dental tissue-derived mesenchymal stem cells have been proposed as an alternative source for mesenchymal stem cells. Here, we investigated the differentiation ability toward insulin producing cells (IPCs) of human dental pulp stem cells (hDPSCs) and human periodontal ligament stem cells (hPDLSCs). These cells expressed mesenchymal stem cell surface markers and were able to differentiate toward osteogenic and adipogenic lineages. Upon 3 step-IPCs induction, hDPSCs exhibited more colony number than hPDLSCs. The mRNA upregulation of pancreatic endoderm/islet markers was noted. However, the significant increase was noted only for PDX-1, NGN-3, and INSULIN mRNA expression of hDPSCs. The hDPSCs-derived IPCs expressed PRO-INSULIN and released C-PEPTIDE upon glucose stimulation in dose-dependent manner. After IPCs induction, the Notch target, HES-1 and HEY-1, mRNA expression was markedly noted. Notch inhibition during the last induction step or throughout the protocol disturbed the ability of C-PEPTIDE release upon glucose stimulation. The results suggested that hDPSCs had better differentiation potential toward IPCs than hPDLSCs. In addition, the Notch signalling might involve in the differentiation regulation of hDPSCs into IPCs.

High glucose condition suppresses neurosphere formation by human periodontal ligament-derived mesenchymal stem cells.

D‐Glucose serves many roles in cellular functions, but its role in human periodontal ligament‐derived mesenchymal stem cells (hPSLSCs) is yet unknown. Here, the roles of high glucose concentration on neurogenic differentiation by hPDLSCs were investigated. Two‐stage neurogenic induction protocol was employed. Cells were maintained in normal neurogenic induction medium, high glucose condition, or high mannose condition. The results showed that high glucose attenuated neurosphere formation efficiency by hPDLSCs in terms of morphology, neurogenic marker expression, without a deleterious effect on cell viability. Contrastingly, neurosphere‐derived cells matured in high glucose condition exhibited normal neuronal characteristics compared to the control. During neurosphere formation in high glucose, glucose transporters (GLUTs) mRNA levels were significantly decreased, corresponding with the deprivation of cellular glucose uptake. Further, a glucose uptake inhibitor, cytochalasin B, was used to confirm the deleterious effects of glucose uptake deprivation during neurosphere formation. The results demonstrated that deprivation of glucose uptake attenuated neurosphere formation efficiency by hPDLSCs. Together, the results illustrated that high glucose condition attenuated the efficiency of neurosphere formation but not neuronal maturation, which may occur through the downregulation of GLUTs and the reduction of glucose uptake. J. Cell. Biochem. 115: 928–939, 2014.