Embryonic stem cells differentiate into insulin-producing cells without selection of nestin-expressing cells.

We present a new strategy for the differentiation of embryonic stem (ES) cells into insulin-producing cells via a multi-step process without selection and induction of nestin-positive cells. During ES cell differentiation, transcript levels of genes characteristic of early and mature beta cells including Pdx1, Pax4, insulin and islet amyloid pancreatic peptide are up regulated. Islet-like clusters are characterized by expression of C-peptide, insulin and partially cytokeratin 19 as well as by ion channel activity similar to that found in embryonic beta cells. Cells of islet-like clusters show glucose-dependent insulin release at terminal stage. At an intermediate stage, nestin is partially co-expressed with C-peptide and cytokeratin 19, whereas islet-like clusters at the terminal stage are nestin-negative. We conclude that expression of nestin and cytokeratin 19 is a normal property of ES cells preceding differentiation into C-peptide/insulin-producing cells without any selection for nestin-positive phenotypes.