Transient acid treatment cannot induce neonatal somatic cells to become pluripotent stem cells
Tang MK., Lo LM., Shi WT., Yao Y., Lee HSS., Lee KKH.
<ns4:p>Currently, there are genetic- and chemical-based methods for producing pluripotent stem cells from somatic cells, but all of them are extremely inefficient. However, a simple and efficient technique has recently been reported by Obokata <ns4:italic>et al </ns4:italic>(2014a, b) that creates pluripotent stem cells through acid-based treatment of somatic cells. These cells were named stimulus-triggered acquisition of pluripotency (STAP) stem cells. This would be a major game changer in regenerative medicine if the results could be independently replicated. Hence, we isolated CD45<ns4:sup>+</ns4:sup> splenocytes from five-day-old Oct4-GFP mice and treated the cells with acidified (pH 5.7) Hank’s Balanced Salt Solution (HBSS) for 25 min, using the methods described by Obokata <ns4:italic>et al</ns4:italic> 2014c. However, we found that this method did not induce the splenocytes to express the stem cell marker Oct4-GFP when observed under a confocal microscope three to six days after acid treatment. qPCR analysis also confirmed that acid treatment did not induce the splenocytes to express the stemness markers <ns4:italic>Oct4</ns4:italic>, <ns4:italic>Sox2</ns4:italic> and <ns4:italic>Nanog</ns4:italic>. In addition, we obtained similar results from acid-treated Oct4-GFP lung fibroblasts. In summary, we have not been able to produce STAP stem cells from neonatal splenocytes or lung fibroblasts using the acid-based treatment reported by Obokata <ns4:italic>et al</ns4:italic> (2014a, b, c).</ns4:p>