Table 1.
Comparison of relative levels in the presence or absence of FOXO1 inhibitor in decidualizing endometrial stromal cells.
Fig 1.
Relative gene expression levels in response to different concentrations of insulin in decidualizing endometrial stromal cells.
Relative gene expression levels of IGFBP1, CTGF, INSR, DCN, LEFTY2, and FOXO1 in response to 5, 50 and 500 nM insulin in in vitro decidualized human endometrial stromal cells after 6 days. The values presented are medians and ranges (min-max). * = p < 0.05; ** = p < 0.01; *** = p < 0.001 in comparison to the control value.
Fig 2.
Micrographs and forward and side scatter analysis of undifferentiated stromal and decidualized cells in the absence or presence of insulin.
Representative micrographs of undifferentiated stromal and decidualized cells (MPA + db-cAMP) in the absence or presence of insulin were taken using an inverted microscope with 40x magnification. Forward vs side scatter (FCS/SSC) dot plot generated by flow cytometer showing the cell distribution of undifferentiated stromal and decidualized cells in the absence or presence of insulin.
Fig 3.
Relative gene expression levels in response to insulin and/or PI3K inhibitor in decidualizing endometrial stromal cells.
Relative levels of IGFBP1, CTGF, INSR, DCN, LEFTY2 and FOXO1 in response 500 nM wortmannin, a PI3K inhibitor in combination with 100 nM insulin in in vitro decidualized human endometrial stromal cells after 4 days. The values presented are medians and ranges (min-max). * = p < 0.05; ** = p < 0.01; in comparison to the appropriate control value.
Fig 4.
FOXO1 immunostaining in response to insulin and/or PI3K inhibitor.
Representative fluorescent micrographs for FOXO1 (green) and DAPI-stained nucleus (blue) in decidualized cells with 630x magnification. FOXO1 is located predominantly in the nucleus in the absence of insulin, while exported from the nucleus in the presence of insulin. Wortmannin, a PI3K inhibitor has no effect on the subcellular localization of FOXO1 alone, while in combination with insulin it blocks insulin induced nuclear export of FOXO1.
Fig 5.
A model on FOXO1 regulation via insulin-induced phosphorylation-dependent degradation.
A model on FOXO1 regulation through insulin-induced phosphorylation-dependent degradation as suggested in some other cell types: PI3K is activated by insulin, the FOXO proteins are phosphorylated, resulting in their transcriptional inactivation through their nuclear export and cytoplasmic retention followed by a multistep negative regulation including ubiquitination and proteasomal degradation [26–31].