Title: 775 – Exogenous Stiffness Results in Nuclear Translocation of Yap1 in an Induced Pluripotent Stem Cell-Derived 3D Model of Human Ulcerative Colitis
Abstract: Bmi1 ctrl ) and Bmi1 CreER ; Rosa26 eYFP ; Klf4 fl/fl (Bmi1 Δ Klf4) mice were exposed to 12 Gy totalbody γ-irradiation (TBI).Tamoxifen was administered 48 h before or 24 h after irradiation to induce recombination in BMI1 + cells and initiate lineage tracing (marked by YFP + cells).Proximal small intestine was collected 0, 6, 24, 48, 72 and 96 h after TBI.RESULTS: Expression of p21 increased and peaked around 48 h after TBI.At this point 60% of surviving YFP + cells co-expressed p21 and majority of them were located around +4 position and in transit amplifying zone.Concomitantly, the number of EdU + cells decreased.During the regenerative phase (48-96 h post-TBI), p21 expression started to diminish while 70% of YFP + cells gained expression of MSI1.RT-qPCR analysis of FACS-sorted YFP + cells collected 48 and 72h post-TBI showed an inverse relationship between Cdkn1a and Msi1 mRNA levels.Luciferase assay showed that MSI1 inhibits p21 translation, which was further confirmed by Western blot analysis of irradiated HCT116 cells.Between 72 and 96 h after TBI, the number of YFP + cells that were EdU + increased.Furthermore, both sham and irradiated Bmi1 ΔKlf4 mice had increased percentage of YFP + MSI1 + cells as compare to Bmi1 ctrl mice.Luciferase assay showed that KLF4 regulates Msi1 transcription.CONCLUSION: Collectively, these data suggest that p21, MSI1, and KLF4 are key factors that regulate survival, activation and activity of rISC-lineages during regeneration of the intestinal epithelium after ionizing radiation-induced injury.
Publication Year: 2019
Publication Date: 2019-05-01
Language: en
Type: article
Indexed In: ['crossref']
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