Adult mice generated from induced pluripotent stem cells

Abstract

Recent landmark experiments have shown that transient overexpression of a small number of transcription factors can reprogram differentiated cells into induced pluripotent stem (iPS) cells that resemble embryonic stem (ES) cells. These iPS cells hold great promise for medicine because they have the potential to generate patient-specific cell types for cell replacement therapy and produce in vitro models of disease, without requiring embryonic tissues or oocytes. Although current iPS cell lines resemble ES cells, they have not passed the most stringent test of pluripotency by generating full-term or adult mice in tetraploid complementation assays, raising questions as to whether they are sufficiently potent to generate all of the cell types in an organism. Whether this difference between iPS and ES cells reflects intrinsic limitations of direct reprogramming is not known. Here we report fertile adult mice derived entirely from iPS cells that we generated by inducible genetic reprogramming of mouse embryonic fibroblasts. Producing adult mice derived entirely from a reprogrammed fibroblast shows that all features of a differentiated cell can be restored to an embryonic level of pluripotency without exposure to unknown ooplasmic factors. Comparing these fully pluripotent iPS cell lines to less developmentally potent lines may reveal molecular markers of different pluripotent states. Furthermore, mice derived entirely from iPS cells will provide a new resource to assess the functional and genomic stability of cells and tissues derived from iPS cells, which is important to validate their utility in cell replacement therapy and research applications.

Concise Review: Induced Pluripotent Stem Cells Versus Embryonic Stem Cells: Close Enough or Yet Too Far Apart?

“…iPSC must have convinced even the most skeptical minds of their developmental potential and pluripotency when tetraploid complementation resulted in viable adult mice [12,13]. It is a definite proof of principle that four transcription factors are able to modify a differentiated cell all the way to the pluripotent state of ESC.…”

“…Furthermore, when injected into blastocysts they should contribute to the embryo tissues, including the germ line. Ultimately, the ability of iPSC to form a whole animal via tetraploid complementation is a clear indication of iPSC pluripotency and a nearly identical state to ESC [12,13] (Fig. 1).…”

iPS : toutes les démonstrations scientifiques sont-elles absolument nécessaires ?

“…Every day in the lab people are worried about getting scooped ». Et voici, en juillet, la publication d'un scoop annoncé, la production de souris entièrement dérivées de cellules iPS, achevant ainsi la démonstration, rigoureuse à souhait maintenant, du caractère pluripotent de ces cellules [7][8][9]. Rien qui ne mérite vraiment publication dans des revues prestigieuses.…”

“…C'est ainsi que le caractère pluripotent des cellules ES murines, dérivées de la masse cellulaire interne du blastocyste pré-implantatoire a été démontré, il y a plus de vingt ans [10], ou, plus récemment, celui de cellules ES obtenues après transfert nucléaire. De l'autre, la production de cellules iPS par la technique maintenant classique et « ancienne » de Shinya Yamanaka [11], consistant en l'expression transitoire de quatre facteurs de transcription Oct4/Sox2/Klf4/cMyc à l'aide d'un vecteur viral, les cellules cibles étant, dans les trois articles évoqués ici, des fibroblastes murins embryonnaires [7][8][9]. On sait que ces iPS contribuent à la formation d'animaux chimères viables et fertiles ; restait à démontrer qu'elles avaient strictement les mêmes propriétés que les ES, et donc pouvaient « complémenter » un « embryon tétraploïde ».…”

An imprinted signature helps isolate ESC-equivalent iPSCs

“…At this point, it should be noted that ES cells generated by nuclear transfer-mediated reprogramming (NT-ES cells) from adult somatic cells are indistinguishable from normal ES cells including the parameter of 4N complementation. Surprisingly, last year, several groups succeeded to derive iPSC lines that could generate live pups via 4N complementation at levels comparable to ESCs [6][7][8], thus demonstrating that indeed, ESC equivalent pluripotent cells could be generated from differentiated cells with the induction of one to four reprogramming factors. Unfortunately, without chemical inhibitors, these lines seemed to be rare -even with stringent Oct4 selection and morphological criteria, more than 70% of iPSC lines isolated and tested did not have the capacity to generate a live adult by 4N complementation [6].…”