SCL Student

May Chayosumrit

Directed Differentiation of Human Embryonic Stem Cells into Insulin Producing Cells
hESCs have an indefinite replicative capacity and can be directed to differentiate into any specialized cells of the body, thus providing an invaluable source of transplantable cells and tissues for replacement therapy. However, immune rejection of the grafts continues to be a major issue in transplantation. We have previously shown that encapsulated hESCs and mouse ESCs placed in alginate hydrogel microcapsules prevented formation of teratomas in immunodeficient (SCID) and immunocompetent (BALB/c) mice, respectively. Encapsulated hESCs showed spontaneous differentiations both under in vivo and in vitro conditions. However, the viability of encapsulated hESC in the culture significantly decreased after one week. We have currently optimized the culture conditions and the configuration of alginate capsules in order to maintain viability of encapsulated hESCs.

Single cells could proliferate and differentiate in three dimensional (3D) cultures. Upon the directed differentiation using growth factors, encapsulated hESCs could differentiate into insulin-expressing cells following stages during pancreatic development. Analysis of gene expression by qPCR showed that the encapsulated hESCs expressed markers resembling definitive endoderm, Sox17 and Foxa2, gut-tube endoderm, HNF1b, posterior foregut, Pdx1 and HLXB9, pancreatic endoderm, Pdx-1, endocrine precursors, Ngn3 and Insulin while the pluripotency gene, Nanog, were downregulated. Future attempts include optimization of the differentiation protocol and further characterization of the encapsulated hESC phenotype in the microcapsule environment.