%0 Journal Article
%T Progress and bottleneck in induced pluripotency
%A Zhen-Ning Zhang
%A Yang Xu
%J Cell Regeneration
%D 2012
%I BioMed Central
%R 10.1186/2045-9769-1-5
%X The pluripotent cells in the inner cell mass (ICM) are able to differentiate into each cell type of the three germ layers [1], and give rise to embryonic stem (ES) cell lines [2,3]. Considering their unlimited self-renewal capability and pluripotency to differentiate into all cell types in the body, human pluripotent stem cells (hESCs) hold great promise in human cell therapy. However, one major drawback of the hESC-based cell therapy is the allogenic immune rejection of hESC-derived cells by the recipients. While persistent systemic immune suppression could prevent the rejection of the allogenic hESC-derived cells, the long-term immunosuppression has serious side effects such as the increased risk for cancer and infection [4]. Therefore, it would be highly desirable to develop pluripotent cells with the same genetic makeup as the patients, as the cells derived from the patient-specific pluripotent cells are considered autologous and thus can be transplanted without the risk of immune rejection.While it had been assumed that differentiating cells gradually lose their plasticity during development and the terminally differentiated cells could not give rise to another cell type, this assumption has been challenged by the discovery of nuclear reprogramming that allows the switch of cell identity from one cell type to another. Somatic nuclear reprogramming to convert a somatic nucleus into the pluripotent state was first described in 1950s when researchers transferred nuclei from amphibian blastula into enucleated eggs, resulting in adult individuals [5,6]. In subsequent experiments, this somatic cell nuclear transfer (SCNT) technology could achieve the same results with the nucleus from more differentiated cells such as intestinal cells and skin cells [7,8]. One of the most exciting developments in the somatic nuclear reprogramming is the first success in mammalian SCNT in 1997 to produce the cloned sheep Dolly by transferring the nuclei of adult mammary gland cells in
%U http://www.cellregenerationjournal.com/content/1/1/5