| Nuclear transfer |
A somatic cell nucleus is fusioned with a mature enucleated oocyte |
hES cell lines can be established via heterologous fusion. |
Epigenetic reprogramming outcome is impossible to predict |
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| Cell extracts |
Differentiated cells are incubated with ES cells extracts in order to drive them to express ES cells profiles. |
It allows biochemical and kinetic analysis of reprogramming. It may result useful for genetic identification of reprogramming factors. |
Difficult to conclude if the protein expression profile of the target cell corresponds to its own protein production or if it is consequence of the transient expression of the protein molecules taken from the extracts in which the cells are growing. |
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| Forced expression of defined factors |
Transfection of embryonic cells with set combinations of Oct4, Sox2, c-Myc, Klf4, Nanog, Stat3, Lin28, Esrrb, SV40LT, UTF-1, p53 siRNA, hTERT, Wnt3a and Nr5a2. |
The most explored technique that has given higher efficiencies. Non-integration approaches may lead to safe clinical applications. Used with LMW increases efficiencies. |
Use of retrovirus and adenovirus can cause reactivation of cancer genes once they are fully integrated in the host's genome. The dedifferentiation protocols have not been streamlined yet as techniques are not fully optimized. |
0.001 to 4.4%, depending on the cell line. The best efficiencies are given by RNA transduction.
When OSKM+p53 siRNA+UTF-1 are used efficiencies increase up100X, compared with OSKM alone. |
| Synthetic molecules |
Low molecular weight (LMW) compounds may be used as reprogramming reagents. Reversina has been able to generate cells with osteogenic and adipogenic differentiation capabilities from myoblasts. Suberaylanide hidroxamic acid (SAHA), trichostatin A (TSA), valproic acid (VPA), 5' azaC, RG108, BIX-01294, A-83-01, BayK8644 and dexamethasone have also been used. |
May be useful as a tool for controlling stem cell fate and for further understanding of developmental processes. |
There is not a single compound with ability to generate iPS cells. Only cells with different differentiation abilities from the original have been generated. |
The use of certain LMW compounds was able to increase 2.6 - 100 times the reprogramming efficiency when combined with forced expression of defined factors. |
| miRNA |
The objective of this method is to alter the cell protein synthesis profile via microRNAs. |
When used with forced expression of defined genes, Mir-290 can replace c-Myc. |
It is not well understood yet as to how transcription factors and miRNAs interact. |
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