Islet cells from human embryonic stem cells

DETAILED DESCRIPTION This invention solves the problem of generating large populations of human islet cells by showing how to efficiently differentiate them from pluripotent stem cells.
It has been discovered that stem cells can be coaxed along the islet cell differentiation pathway by initiating differentiation towards the endodermal lineage, and focusing the differentiation process by culturing in the presence of factors that facilitate outgrowth of islet cells.
This invention provides a system for producing a population of cells enriched for multipotent islet cell progenitors, capable of forming mature islets.
If desired, the differentiation process can continue in order to maintain mature endocrine-secreting cells.
As an aid to optimizing the differentiation process, this disclosure provides a strategy of dividing the differentiation pathway into a series of sequential stages.
In this way, factors effective in pushing the cells along each segment of the differentiation pathway can be identified.
In the illustration described in Example 5, the differentiation process proceeded as follows.
For Stage 1, undifferentiated human embryonic stem cells from feeder free culture were differentiated so as to form a mixed cell aggregate containing endoderm cells in suspension culture.
Retinoic acid was used as the initial differentiation agent, in combination with enrichment factors selenium and T3.
For Stage 2, differentiation to pancreas progenitor cells was effected by culturing in a medium containing Noggin (200 ng/ml), EGF (20 ng/ml) and bFGF (2 ng/ml).
For Stage 3, differentiation to end-stage islet cells was induced by withdrawing the Noggin, EGF and bFGF, and instead culturing the cells with 10 mM nicotinamide.
As shown in FIG.
4, clusters of cells were obtained synthesizing antibody-detectable levels of c-peptide of insulin and somatostatin.
Methods to efficiently produce islet stem cells from pPS cells are important, because pPS cells can be caused to proliferate indefinitely.
This invention provides a system that can be used to generate unbounded quantities of islet progenitors—and progeny that are committed to form mature islet cells