Differentiated cells can be reprogrammed into pluripotent stem cells,known as“induced pluripotent stem cells”(iPSCs),through the overexpression of defined transcription factors.The creation of iPSC lines has opened new avenues for patient-specific cell replacement therapies for regenerative medicine.However,the clinical utilization of iPSCs is largely impeded by two limitations.The first limitation is the low efficiency of iPSCs generation from differentiated cells.The second limitation is that many iPSC lines are not authentically pluripotent,as many cell lines inefficiently differentiate into differentiated cell types when they are tested for their ability to complement embryonic development.Thus,the“quality”of iPSCs must be increased if they are to be differentiated into specialized cell types for cell replacement therapies.Overcoming these two limitations is paramount to facilitate the widespread employment of iPSCs for therapeutic purposes.Here,we summarize recent progress made in strategies enabling the efficient production of high-quality iPSCs,including choice of reprogramming factors,choice of target cell type,and strategies to improve iPSC quality.
Pluripotent stem cells(PSCs),including embryonic stem cells(ESCs)and induced PSCs(iPSCs),can differentiate into cells of the three germ layers,suggesting that PSCs have great potential for basic developmental biology research and wide applications for clinical medicine.Genuine ESCs and iPSCs have been derived from mice and rats,but not from livestock such as the pig-an ideal animal model for studying human disease and regenerative medicine due to similarities with human physiologic processes.Efforts to derive porcine ESCs and iPSCs have not yielded high-quality PSCs that can produce chimeras with germline transmission.Thus,exploration of the unique porcine gene regulation network of preimplantation embryonic development may permit optimization of in vitro culture systems for raising porcine PSCs.Here we summarize the recent progress in porcine PSC generation as well as the problems encountered during this progress and we depict prospects for generating porcine naive PSCs.
