Adipose Stromal Cells are a More Efficient Source than Adipose Stem Cells in Retrovirus-Mediated iPS Induction

Recently, adipose tissue-derived mesenchymal stem cells (MSCs) were reported to be a valuable cell source for generating induced pluripotent stem (iPS) cells because adipose tissue is readily obtainable and possesses high quantities of MSCs. To date, little research has been conducted to characterize the efficiency of iPS induction in adipose tissue. Human iPS cells were generated from adipose tissue-derived MSCs (AT-MSCs) and stromal cells (AT-SCs) via a retroviral delivery system. The reprogramming efficiency of AT-MSCs and AT-SCs were 0.008 and 0.014%, respectively, in terms of the expression of the TRA-1-60 antibody and 0.023 and 0.041%, respectively, regarding alkaline phosphatase staining. This differential reprogramming capability resulted from different levels of viral infectivity between the two cell types. Viral infectivity using pMXs-IRES-GFP was notably low in AT-MSCs and the quantities of OSKM (OCT4, SOX2, KLF4 and c-MYC) in AT-MSCs were 22.5–31.6% of AT-SCs. In conclusion, the amount of transgenes leads to a higher reprogramming efficiency in AT-SCs compared with AT-MSCs. The present study shows that the induction efficiency of pluripotent cells from somatic or adult stem cells could depend on the viral susceptibility of the target cells. Therefore, non-MSCs could be a more efficient source for reprogramming by retrovirus-mediated iPS induction.