この論文は多能性段階を維持している細胞にJAKiを入れるとその機能が壊れて分化を開始するから
多能性マーカー遺伝子の発現が減少してくるというものね。
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16. Yang, J. et al. Stat3 activation is limiting for reprogramming to ground state pluripotency. Cell Stem Cell 7, 319–328 (2010)
その意味ではレター論文の記述も変だね。原論文では普通のES細胞やEpiSCの他にiPS細胞も使われている。
inner cell mass (ICM)-type pluripotent cellsとは限らない。多能性細胞に関しての研究だ。
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Previous studies have indicated that inner cell mass (ICM)-type pluripotent cells can be removed from culture by treating the culture with a JAK inhibitor <16>(Extended Data Fig. 5a, b).
Fig3
FI細胞をLIF+FBS培地で培養するとOct4、Nanog, SSEA-1を発現してきてES様細胞（STAP幹細胞）となり、このES様細胞は,TSマーカ（インテグリンα７、Eomes９）の発現を失う。
b ES様細胞はES並みの遺伝子発現（Oct4,Nalog,Rex1Kelf24,Sox2,Esrrb・・・）を保つが
TS並みの遺伝子発現（Cdx2、Eomes,、Elf5）を失う。
e f FI細胞はMEKインヒビターを入れて培養するとバラバラになって死んでしまうが、ES細胞は生き残る （TSとFIはFGF-MEKシグナル系に依存しているが、ESは依存していない）。
リジェンドは以下だね。
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a, Culture of Oct4-GFP Fgf4-induced cells in LIF + 20% FBS medium.
b, qPCR analysis of ES-like cells derived from Fgf4-induced cells for pluripotent marker genes (left) and trophoblast marker genes (right). Values are shown as ratio to the expression level in ES cells (left) or trophoblast stem (TS) cells (right).
c, d, Culture of Oct4-GFP Fgf4-induced cells sorted by FACS for strong integrin α7 (Itga7) expression in LIF + 20% FBS medium.
d, Formation frequency (shown by percentage) of Oct4-GFP+ colonies from cells plated on gelatin-coated dishes at a clonal density. **P < 0.01; t-test; n = 3.
e, f, Culture of Oct4-GFP Fgf4-induced cells (dissociated) in LIF + 20% FBS medium with MEK inhibitor. **P < 0.01; NS, not significant; Tukey’s test; n = 3.
e, No substantial formation of Oct4-GFP+ colonies was seen from Fgf4-induced cells in the presence of MEK inhibitor (left), whereas colonies frequently formed when cells were co-plated with Oct4-GFP ES cells (right; plated cells were 1/20 of Fgf4-induced cells).
f, Quantification of colony formation per plated cells (1 × 103 Fgf4-induced cells and/or 1 × 103 ES cells). Unlike Fgf4-induced cells, ES cells formed colonies (regardless of co-plating with FI-SCs) in the presence of MEK inhibitor. Bars and error bars represent mean values and s.d., respectively (b, d, f). Scale bars: 100 μm (a, c, e).
キメラができて初めてその細胞が多能性細胞であったということになるんで、何が
キメラになったのかが分からないのに分かってないものを分からないままにいくら
分析しても意味ないよね。T細胞がキメラになったとは証明されていない。T細胞は
実際FACSで分画されて酸浴細胞になってるんだけどね。
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The emergence of Oct4-GFP+ cells at the expense of CD45+ cells was also observed by flow cytometry (Fig. 1c, top, and Extended Data Fig. 1b, c). We next fractionated CD45+ cells into populations positive and negative for CD90 (T cells), CD19 (B cells) and CD34 (haematopoietic progenitors), and subjected them to low-pH treatment. Cells of these fractions, including T and B cells, generated Oct4-GFP+ cells at an efficacy comparable to unfractionated CD45+ cells (25–50% of surviving cells on day 7), except for CD34+ haematopoietic progenitors, which rarely produced Oct4-GFP+ cells (<2%; Extended Data Fig. 1d).
本文にあるね。
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To confirm further that Fgf4-induced stem cells with a trophoblast-like nature were converted into ES-like cells, rather than just selecting ES-like cells pre-existing in the Fgf4-induced stem cell culture, we examined the effect of the MEK inhibitor PD0325901 on the ES-like cell generation from Fgf4-induced stem cells. Like trophoblast stem cells, Fgf4-induced stem-cell survival is dependent on FGF–MEK signals, and the inhibition of MEK activity caused massive cell death (Extended Data Fig. 6c). However, PD0325901 is also known to be a main effector in 2i medium[17] and to promote ES cell maintenance. Addition of PD0325901 to LIF+FBS-containing medium strongly inhibited the formation of ES-like colonies from Fgf4-induced stem cells (Fig. 3e, left, and Fig. 3f). This inhibition was unlikely to be due to secondary toxic effects from massive cell death of Fgf4-induced stem cells, as colonies formed in the presence of PD0325901 when ES cells were co-plated in the same culture with Fgf4-induced stem cells (Fig. 3e, right, and Fig. 3f).
リジェンドには以下のようにあるわね。
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g, FACS analysis of integrin α7 expression in Fgf4-induced stem cells. Over 40% of Fgf4-induced stem cells strongly expressed both the pluripotency marker Oct4-GFP and the trophoblast marker integrin α7. The bottom panel shows an isotype control for integrin α7 antibody. In ES cells, integrin-α7-expressing cells were less than 0.1% (data not shown; three independent ES cell lines were examined).
