Method for preparing pancreatic beta cells starting from beta cell progenitors and beta cells thereby obtained

Method for preparing pancreatic islet cells starting from progenitor cells comprising the steps of:

• a) isolating progenitor cells from the pancreas of an adult mammal, by the steps of:
• i) providing transgenic mammals, preferably animals such as rodents, expressing a reporter gene under the control of a suitable progenitor-cell-specific promoter,
• ii) detecting the presence of said progenitor cells by detecting the product of said reporter gene, and
• iii) isolating the progenitor cells detected in step ii),
• b) inducing differentiation of said isolated progenitor cells into differentiated pancreatic islet cells, and
• c) proliferating the differentiated pancreatic islet cells obtained in step b).

A method for identifying the regulatory factors for the differentiation of islet (e.g. alpha-, beta-, delta-, or pp-) cell progenitors into biologically active islet cells comprising the steps of:

• a) isolating progenitor islet cells from the pancreas of an adult mammal, by the steps of:
• i) providing transgenic mammals, preferably animals such as rodents, expressing a reporter gene under the control of a suitable promoter,
• ii) detecting the presence of said progenitor cells by detecting the product of said reporter gene, and
• iii) isolating the progenitor cells detected in step ii),
• b) culturing the cells obtained in step a) in the presence or absence of regulatory factors,
• c) monitoring differentiation of the progenitor cells into functional beta cells in order to identify those factors needed for differentiation of progenitor islet cells into functional pancreatic islet cells.