Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/27923
Title: In vitro differentiation of stem cells towards islet-like cells
Authors: NGO KAE SIANG
Keywords: Mesenchymal, Umbilical cord-derived stem cells, adipose-tissue derived stem cells, islet-like cells, insulin, glucagon
Issue Date: 8-Jul-2011
Source: NGO KAE SIANG (2011-07-08). In vitro differentiation of stem cells towards islet-like cells. ScholarBank@NUS Repository.
Abstract: Mesenchymal stem cells of different origins were shown to differentiate into insulin producing cells under appropriate conditions. This study assessed the potential of umbilical cord lining stem cells (CLSCs), Wharton?s jelly derived mesenchymal stem cells (WJSCs), and adipose tissue derived mesenchymal stem cells (ADSCs) to differentiate into islet-like cells. The basic morphology, pluripotency markers, immunophenotyping surface markers of mesenchymal stem cells, and possible marker of pancreatic progenitor cells, nestin, and sox17 of stem cells derived from umbilical cord, Wharton?s jelly, and adipose tissue were defined and described. We investigated the potential of WJSCs ,CLSCs and ADSCs to differentiate into islet-like cells in vitro using a 3 stage differentiation protocol which had successfully differentiated bone marrow derived mesenchymal stem cells into glucose responsive insulin secreting pancreatic islet-like clusters as described by Sun et al. (Sun, Chen et al. 2007). Transcripts of glucagon, proprotein convertase 1/3, ISL-1, and Nkx6-1 were consistently upregulated at the end of differentiation in CLSCs, WJSCs, and ADSCs. Other markers such as insulin, proprotein convertase 2, somatostatin, Glut2 transporter, glucokinase, pdx1, pax4, pax6, mafA, neuroD1, neurogenin3 were upregulated at transcript level at the end of differentiation, but not in a consistent manner. The differentiated islet-like clusters which were shown to express insulin at transcript level also stained positively with dithizone, a zinc chelating agent that selectively stains insulin producing cells. C-peptide was also detected by ELISA in one of the experiments. Furthermore, the protein expression of glucagon, another hormone known to be produced by islets of Langerhans, was also verified by immunostaining. ADSCs, WJSCs and CLSCs were subjected to the 7-day differentiation protocol described by Chiou et al. to determine if a shorter period of differentiation could be achieved (Chiou, Chen et al. 2011). The 7-day differentiation protocol contained defined factors which were similar to the combination of factors of stage 2 and stage 3 of the 3-stage differentiation protocol but the time required for differentiation was shorter. CLSCs and ADSCs could not tolerate this recipe and the cells started to die. Furthermore, the pancreatic lineage profile of these differentiated ADSCs and CLSCs was not comparable to the differentiated clusters underwent 3-stage differentiation protocol. Upregulation of expression of glucagon, somatostatin were not detected in ADSCs and upregulation of expression of PC2, and somatostatin were not detected in CLSCs that underwent 7-day differentiation protocol. WJSCs tolerated the protocol but insulin expression was not detected at the end of differentiation. In conclusion, Wharton?s Jelly derived-stem cells, cord lining stem cells and adipose tissue derived stem cells have potential to differentiate into islet-like insulin expressing cells in response to defined culture conditions. However, further optimization is required to obtain consistent glucose responsive insulin secretion from these differentiated cells.
URI: http://scholarbank.nus.edu.sg/handle/10635/27923
Appears in Collections:Master's Theses (Open)

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