Table 1.
Comparison of Different Reprogramming Methods
| Delivery methods | Efficiency | Cell types | Advantage | Disadvantage | References | ||
|---|---|---|---|---|---|---|---|
| Retroviral vector | Gamma | Ecotropic | High | MEF, mouse gingival fibroblasts, sensitized human fibroblasts | Lasting expression, packaging cell lines available | Insertional mutagenesis, residual expression of reprogramming factors, reactivation of reprogramming factor in iPSC-derived cells, titer loss during viral concentration and storage, infect rodents only, do not infect nondividing cells, do not infect human cells without mCAT1 sensitization, premature silencing, more immunogenic | 1,19,22,23 |
| Amphotropic | High | Human mesenchymal stromal cells, human dermal fibroblasts, human keratinocytes, human CD133+ cells, nonhuman primate fibroblasts | Lasting expressoin, packaging cell lines available | Insertional mutagenesis, residual expression of reprogramming factors, reactivation of reprogramming factors in iPSC-derivaved cells, titer loss during viral concentration and storage, limited tropism, do not infect nondividing cells, premature silencing, more immunogenic, multiple transduction required for human cells | 24–28,30 | ||
| Pantropic | High | Human T cells, HUVEC, human adipose stem cells, human fibroblasts, human NSC, diseased human fibroblasts, monkey fibroblasts and liver cells | Infect wide range of cells, lasting expression | Insertional mutagenesis, residual expression of reprogramming factors, reactivation of reprogramming factors in iPSC-derived cells, do not infect nondividing cells, no efficient packaging cell lines available due to the toxicity of VSV-G, premature silencing, more immunogenic | 32–41 | ||
| Lentiviral | High | Human cells, murine terminal β cells, rat cells, pig cells | Lasting expression of transgenes; infect wide range of cells; easy concentration and storage of virus. Infect nondividing cells, slower silencing, available inducible systems | Insertional mutagenesis, residual expression of reprogramming factors, reactivation of reprogramming factors in iPSC-derived cells, No efficient packaging cell lines avaible due to toxicity of VSV-G | 2,58–62 | ||
| Sendai viral vector | Very high | Human T cells, BJ, HDF, MEF, Human CD34+ cells | Nonintegrating, no premature silencing, broad tropism | Immunogenic, fusogenic, multiple vectors required, expensive, virus curing process needed, screening for integrations may be required, virus preparation | 52,78–82 | ||
| Transient transfection | Very low | MEF, human foreskin fibroblasts | Nonintegrating, inexpensive, no virus preparation | Low efficiency, multiple rounds of transfection, occational integration, difficulty in transfection of primary cells, excludes the use of nucleofection for adherent cells due to multiple transfection, vector silencing | 51,66,67,70,110 | ||
| EBV episomal plasmids | Low | Human CD34+ cells, cord blood MNC, bone marrow MNC, human fibroblast, human NSC | Nonintegrating, inexpensive, no virus preparation, single transfection, transfect primary cells using nucleofection, reasonable efficiency when additional factor used, low immunogenicity | Need additional reprogrammming factors, occasional genomic integration, inefficient, cell death when nucleofection used, does not work with rodent cells, vector silencing | 31,49,53,99–103 | ||
| Protein | Very low, long kinetics | MEF, Human newborn fibroblasts, BJ, Mouse fibroblasts | Abosolute nongenome integration, controllable factor stimulation (timing, concentration and temporal sequence) | Inefficient, multiple transductions, affected by quality of recombinant proteins | 48,54,73,74 | ||
| Synthetic mRNA | Low | ESC-derived fibroblasts, BJ, D551, MRC-5, patient fibroblasts | Nonintegrating, controllable factor stimulation (timing, concentration, and temporal sequence) | Intense innate immune response, multiple transfections, limited cell types, expensive, labor-intensive, challenging transfection, RNA instability, low reprogramming efficiency, additional factor (LIN28 and/or NANOG) required | 50,87 | ||
| Replicating synthetic RNA | Low | BJ, primary HFF | Nonintegrating, single transfection | Strong innate immune response, cytopathic, expensive, inefficient | 90 | ||
| Adenoviral vector | Very low | Hepatocytes, human fibroblasts | Nonintegrating | High spontaneous integration, inefficient, virus-based, limited cell types, high virus titer required, transient expression | 132,134 | ||
| PiggyBac | Low | MEF | Excisible integration, no foot-print, less immunogenic | Insertional mutagenesis, extra excision step, inefficient excision, inefficient reprogramming, integration of helper plasmids | 121,122 | ||
| microRNA mimic | Low | Mouse adipose stromal cells, human adipose stromal cells, HDF | Nonintegrating, easy synthesis, controllable administration (time and concentration) | Inefficient, transient expression, multiple transfections | 146 | ||
| Preintegrated, inducilbe system | Very high | All reprogrammable murine cells from transgenic mice including cells difficult to culture and cells refractory to direct transduction, iPSC-derived human fibroblasts, | Temporal control of expression, reprogram terminally differentiated cells, reprogram hard-to-transfect cells, genetically homogenous cells, good for research reprogramming (genetic and chemical screening, mechanistic study), no direct virus transduction, available transgenic mice | Position effect, insertional mutagenesis, limited power for human cells, not suitable for clinical reprogramming, transgenic cells from current transgenic mice may not be optimal for efficient reprogramming, varied efficiency between available transgenic mice. | 64,128,129 | ||
| Minicircle | Very low | Human adipose stem cells | Nonintegrating, inexpensive, low immunogenic | Inefficient, occasional integration, additional factors used, limited cell types, multiple transfections | 71,72 |
Cell types: listed are generally the types of reprogramming cells used in the references. Efficiency in column 2 is the reprogramming efficiency rated by the author. A percentage is not listed given that such a number is not accurate and may be misleading, because it is affected by cell types, criteria used, and other factors. For example, reprogramming efficiencies were evaluated in different references by AP+ colonies, Tra-1-60+ colonies, SSEA1+ colonies, colony morphology, Oct4-GFP+ colonies, Nanog+ colonies, and number of iPSC lines established. In addition, flowcytometry percentage of marker positive cells in the reprogramming populations was frequently used in the literature. However, examination time has a great impact on this number due to the rapid proliferation of the reprogrammed cells.
MNC, mononulcear cells; HDF, human dermal fibroblasts; NSC, neural stem cells; HFF, human foreskin fibroblasts; HUVEC, human umbilical vein endothelial cells; EBV, Epstein Barr virus; ESC, embryonic stem cell; iPSC, induced pluripotent stem cell; MEF, mouse embryonic fibroblast; VSV-G, vesicular stomatitis virus G protein.