FIG. 1.

Culture of Lin⁻c-kit⁺Sca1⁺ (LKS⁺) cells in vitro selectively activates p38. (A, B) Activation of p38, Erk, and JNK was determined by immunofluorescent staining with anti-phosphorylated-p38 (p-p38), phosphorylated-Erk (p-Erk), or phosphorylated-JNK (p-JNK) primary antibodies and Alexa fluor-555–conjugated goat anti-rabbit IgG secondary antibodies (red). The nuclei of the cells were stained with DAPI (blue). Representative photomicrographs of p-p38, p-Erk, and p-JNK immunofluorescent staining are shown. (A) p38, Erk, and JNK activation in freshly isolated LKS⁺ cells (day 0) and the cells expanded from LKS⁺ cells after 7-day culture. (B) p38 activation in freshly isolated LKS⁺ cells (day 0) and the cells expanded from LKS⁺ cells after 7-day culture with dimethyl sulfoxide (DMSO) (vehicle) or SB230580 (SB, 5 μM). Magnification 400×. (C) Analysis of p38 activation in LKS⁺ cells by phospho-specific flow cytometry. Representative flow cytometric analyses of p-p38 in freshly isolated LKS⁺ cells and LKS⁺ cells after 7-day culture with DMSO (vehicle) or SB230580 (SB, 5 μM) are shown. CTL represents a control staining with an isotype control antibody for p-p38.