Researchers produced a new class of pluripotent stem cells using cellular reprogramming
The remarkable discovery of induced pluripotent stem cell technology by Japanese researcher Shinya Yamanaka has revolutionized the field of stem cell biology. Yamanaka and his group showed that somatic cells can be reprogrammed by transferring their nuclear material into oocytes or by fusion with embryonic stem (ES) cells, indicating that unfertilized eggs and ES cells contain factors that can confer totipotency or pluripotency to somatic cells . This cutting-edge finding has since advanced stem cell research. The creation of patient-specific disease cell lines can help scientists model a disease in a petri dish for the study and possible treatment of degenerative disorders with autologous cells.
The ectopic expression of Oct4, Klf4, c-Myc and Sox2 (OKMS) is now a well-established strategy, which successfully allows reprogramming of somatic cells into induced pluripotent stem cells. Several reports have already shown the successful reprogramming of human fibroblasts into a wide variety of other cell types, including pancreatic β cells, neural stem cells, mature B cells, stomach and liver cells, melanocytes, adipose stem cells and keratinocytes, demonstrating the potential of the tool. (However, there is still debate: Are induced pluripotent stem cells indeed the true equivalents of embryonic stem cells?)
Recently, Dr. Andras Nagy and coworkers at Mount Sinai Hospital Lunenfeld-Tanenbaum Research Institute in Toronto reported a new kind of steady-state pluripotent stem cell called an “F-class” cell. Scientists used a somatic cell reprogramming approach to generate this new type of cell. Furthermore, they showed that these cells were able to differentiate into all three embryonic precursor tissues.
Scientists used a transposon-based transgene delivery system for reprogramming. The technique has certain advantages over viral infection. The virus approach carry the potential risk of viral infection, and transient transfection limits reprogramming efficiency. The transposons are highly efficient and much more reliable in terms of delivering the reprogramming genes. The researchers exploited the doxycycline-inducible transposon system to initiate reprogramming via triggering the transposons.
The major advantage of this method is consistency, which facilitates less experimental variation and would yield a robust population of stem cells that could be used with confidence in both basic and applied studies.
[1.] Takahashi K, Yamanaka S. Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 2006 Aug 25;126(4):663-76.