title: Transient acid treatment cannot induce neonatal somatic cells to become pluripotent stem cells.
abstract: 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 et al (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 (+) 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 et al 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 Oct4, Sox2 and Nanog.  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 et al (2014a, b, c).
authors: Key Laboratory for Regeneration Medicine, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, Hong Kong.
authors: Mei Kuen
authors: MK
authors: Tang
authors: Key Laboratory for Regeneration Medicine, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, Hong Kong.
authors: Lok Man
authors: LM
authors: Lo
authors: Key Laboratory for Regeneration Medicine, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, Hong Kong.
authors: Wen Ting
authors: WT
authors: Shi
authors: Key Laboratory for Regeneration Medicine, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, Hong Kong.
authors: Yao
authors: Y
authors: Yao
authors: Faculty of Life Sciences, University of Manchester, Manchester, M13 9PL, UK.
authors: Henry Siu Sum
authors: HS
authors: Lee
authors: Key Laboratory for Regeneration Medicine, School of Biomedical Sciences, Chinese University of Hong Kong, Shatin, Hong Kong.
authors: Kenneth Ka Ho
authors: KK
authors: Lee