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).
