Humanembryonic stem cells (hESCs) had widely been used for its characteristics ofpluripotency and self-renewal property in studies of human developmentalprocess, disease modeling and regenerative medicine.
However, the ethicalissues concerned with destruction of human embryo, and the need for life-longimmunosuppressive drugs in case of transplantation of hESCs greatly hampered hESCstransitioning into future clinical applications. Yet, in 2007, the discovery ofinduced pluripotency by Yamanaka have completely transformed the scientificapproach and research into another platform where stem cell research have becomefree of ethical concerns, thus far expanding its boundaries in developmentalstudy and regenerative medicine (1). The adultsomatic cells are introduced with a set of four transcriptional factors, calledYamanaka factors, which are OCT4, SOX2, KLF2, and c-MYC, and are reprogrammedinto induced pluripotent stem cells (iPSCs) that demonstrate pluripotency, selfrenewal and differentiation potential as do hESCs (1). Thisbreakthrough of generating iPSCs has resolved the problem of isolating primarypatient-derived cells such as neurons or cardiomyocytes which are hard toaccess, thus has brought about a wide array of technological and medical developmentin drug screening and disease modeling. The iPSCs that are generated in vitroare stimulated to be differentiated into certain types of cells, which are hardto access and store for long-term, by fostering appropriate environment withchemical agents. These differentiated cells can be replaced infinitely from theiPSC stocks, allowing much more efficient research in disease modeling, drugscreening and cell therapy. Moreover, patient-specific iPSC clinical trial isongoing on age-related macular degeneration (AMD) which is otherwise incurable (2). iPSCshave been derived from a wide varieties of somatic cell types, such askeratinocytes, blood cells or stomach cells, with several differentreprogramming techniques to introduce a cocktail of reprogramming plasmids tosomatic cells (3).
The deliveryof reprogramming transcriptional factors is an essential step that greatly affectsthe efficiency and viability of iPSCs. A number of different approaches havebeen developed to maximize the efficiency of plasmid delivery and itselimination after reprogramming, and quality and viability of resultant iPSCs (3).Inthis paper, human dermal fibroblast, isolated from cesarean scars, are used togenerate iPSCs in feeder-free condition using Sendai viral transduction system,and the resultant iPSC lines are further characterized to examine itspluripotency.