KLF4 Regulates Goblet Cell Differentiation in BMI1＋ Reserve Intestinal Stem Cell Lineage during Homeostasis.

Abstract

Krüppel-like factor 4 (KLF4) is a zinc-finger transcription factor, expressed in villus cells of the intestinal epithelium, that promotes cellular differentiation and tissue homeostasis. Previous studies suggest that BMI1+ cells represent secretory progenitors with reserve intestinal stem cell (rISC) activity. However, it has not been elucidated how KLF4 contributes to crypt regeneration originated from BMI1+ rISC lineage during homeostasis. In this study, Bmi1-CreER;Rosa26eYFP (Bmi1Ctrl) and Bmi1-CreER;Rosa26eYFP;Klf4fl/fl (Bmi1ΔKlf4) mice were injected with tamoxifen to label BMI1+ cells and their lineage and to delete Klf4. During homeostasis, MUC2+ goblet cells appeared in the BMI1+ cell lineage 2, 3 and 7 days after tamoxifen administration. After Klf4 deletion in BMI1+ cells, the number of KLF4+ and MUC2+ cells in eYFP+ cells decreased in Bmi1ΔKlf4 mice compared with Bmi1Ctrl mice. Thus, KLF4 was positively correlated with goblet cell differentiation in BMI1+ cell derived lineage. In ex-vivo analysis, organoids derived from single eYFP+ cells of Bmi1Ctrl mice contained MUC2-expressing cells that co-expressed KLF4. On the other hand, organoids derived from Klf4-deleted eYFP+ cells from Bmi1ΔKlf4 mice showed reduced number of MUC2-expressing cells. In conclusion, these results suggest that KLF4 regulates goblet cell differentiation in BMI1+ ISC-derived lineage during homeostasis.