Methods for the production of iPS cells using non-viral approach
Methods and composition of induction of pluripotent stem cells and other desired cell types are disclosed. For example, in certain aspects methods for generating essentially vector-free induced pluripotent stem cells are described. Furthermore, the invention provides induced pluripotent stem cells and desired cell types essentially free of exogenous vector elements with the episomal expression vectors to express differentiation programming factors.
1. A method of producing human induced pluripotent stem (iPS) cells population and having cells that are essentially free of differentiation programming vector genetic elements, the method comprising the steps of:
a) obtaining a starting population of human somatic cells;
b) obtaining one or more iPS reprogramming vectors comprising an OriP replication origin and one or more expression cassettes encoding iPS reprogramming factors wherein one or more of said expression cassettes comprise a nucleotide sequence encoding EBNA-1 of EBV, or a derivative thereof which has a deletion of residues corresponding to residues 65 to 89 of EBNA-1, and/or a deletion of residues corresponding to residues 90 to 328 of EBNA-1;
c) introducing the iPS reprogramming vector(s) into the human somatic cells;
d) culturing the human somatic cells that comprise the iPS reprogramming vector(s) to effect expression of said reprogramming factors such that traits consistent with embryonic stem cells arise in at least a portion of cells in the cultured cells; and
e) further culturing cells having the embryonic stem cell traits for a sufficient number of generations in the absence of positive selection for the presence of the iPS reprogramming vector(s) to provide human iPS cells that are essentially free of iPS reprogramming vector genetic elements.
2. The method of claim 1 , wherein cells of the starting cell population are fibroblasts, keratinocytes, hematopoietic cells, mesenchymal cells, liver cells, stomach cells, or β cells.
3. The method of claim 1 , wherein the iPS reprogramming factors comprise Sox-2 and Oct-4.
4. The method of claim 3 , wherein the reprogramming factors further comprise Nanog or Lin28.
5. The method of claim 1 , further comprising a step of differentiating the human iPS cells provided in step e).