(英文)
We recently discovered an intriguing phenomenon of cellular fate conversion: somatic cells regain pluripotency after experiencing sublethal stimuli such as a low-pH exposure. When splenic CD45+ lymphocytes are exposed to pH 5.7 for 30 min and subsequently cultured in the presence of LIF, a substantial portion of surviving cells start to express the pluripotent cell marker Oct4 (also called Pou5f1) at day 2. By day 7, pluripotent cell clusters form with a bona fide pluripotency marker profile and acquire the competence for three-germ-layer differentiation as shown by teratoma formation. These STAP cells can also efficiently contribute to chimaeric mice and undergo germline transmission using a blastocyst injection assay.
Although these characteristics resemble those of ES cells, STAP cells seem to differ from ES cells in their limited capacity for self-renewal (typically, for only a few passages) and in their vulnerability to dissociation. However, when cultured in the presence of ACTH and LIF for 7 days, STAP cells, at a moderate frequency, further convert into pluripotent ‘stem’ cells that robustly proliferate (STAP stem cells).
(英文)
Here we have investigated the unique nature of STAP cells, focusing on their differentiation potential into the two major categories (embryonic and placental lineages) of cells in the blastocyst. We became particularly interested in this question after a blastocyst injection assay revealed an unexpected finding. In general, progeny of injected ES cells are found in the embryonic portion of the chimaera, but rarely in the placental portion (Fig. 1a; shown with Rosa26-GFP). Surprisingly, injected STAP cells contributed not only to the embryo but also to the placenta and fetal membranes (Fig. 1b and Extended Data Fig. 1a–c) in 60% of the chimaeric embryos (Fig. 1c).
