Fig. 6

Restoring JAK/STAT3 Activity Promotes DNA Demethylation of Multi-Pluripotency Loci in pre-iPSCs. a Jaki-S2 pre-iPSC colonies cultured and expanded in the presence of LIF plus Jaki (LIF+/Jaki+), LIFAb (LIF+/LIFAb+), or LIF-only (LIF+) for two weeks. Bar = 625 um. b FACS analysis for GFP+ and GFP- cells in expanded Jaki-S2 pre-iPSCs cultured in LIF containing medium supplemented with Jaki, LIFAb, or LIF-only condition for 3 weeks. Numbers represent mean ± SD from three independent experiments. c DNA methylation of Oct4 promoter region measured by bisulfite sequencing for samples described in b. Filled and open circles represent methylated and unmethylated CpGs, respectively. The percentage of total methylated CpGs for the analyzed region was given on top of each dataset. d DNA methylation of IG-DMR region measured by bisulfite sequencing for samples described in b. Filled and open circles represent methylated and unmethylated CpGs, respectively. The percentage of total methylated CpGs for the analyzed region was given on top of each dataset. e The proposed model of JAK/STAT3 in promoting naïve-state pluripotency in reprogramming. LIF activated JAK/STAT3 suppresses Hdacs and stimulates Hats/Kats, Tet1, Dppa3, and PRC2 genes for open chromatin formation in pluripotent and gametogenic loci, promotes their full activation. Dppa3 and PRC2 inhibit de novo methylation of pluripotent loci by Dnmt3s. On the other hand, STAT3 activated Dnmt3s inhibit commitment genes and the OKSM transgenes, the silencing of which are needed for complete reprogramming. This leads to the complete activation of pluripotent circuitry and establishment of naïve-state iPSCs