ABSTRACT
ObjectiveTo explore the function of DANCR during the differentiation of human embryonic stem cells （hESC） toward definitive endoderm （DE）. MethodsThe in vitro DE differentiation system was established and its efficiency was verified. The correlation between the expression level of DANCR and DE differentiation process was detected. Using lentivirus system， we stably knocked down DANCR in hESC. The shDANCR hESC line was applied to DE differentiation， using qPCR and Western blot to detect the expression of DE marker genes SOX17 and FOXA2， and that of primitive streak marker genes Brachyury （T）， EOMES， MIXL1 and GSC. Dual luciferase reporter assay and qPCR were used to confirm the interaction between DANCR and the WNT pathway during DE differentiation. ResultsThe in vitro differentiation system mimicked DE differentiation efficiently. And the expression of DANCR was gradually downregulated during differentiation. DANCR was efficiently knocked down in the shDANCR hESC line （P < 0.001）. Compared with those in the control group， the expression levels of primitive markers Brachyury （T）， EOMES， MIXL1 and GSC， as well as DE markers SOX17 and FOXA2， were significantly decreased in shDANCR groups （P < 0.05）. Furthermore， the transcriptional activity of the WNT pathway in shDANCR groups was lower than that in the control group （P < 0.05）. And RNA levels of downstream genes of the WNT pathway， FZD5， FZD8， SFRP1， FRZB and ANKRD6， were significantly decreased in shDANCR groups （P < 0.05）. However， differences in protein levels of the TGFβ pathway effectors SMAD2/3 and p-SMAD2 were statistically insignificant in shDANCR and control groups （P > 0.05）. Forced activation of β-CATENIN rescued DANCR knock down-induced deficiency in DE differentiation. ConclusionsThe expression of DANCR decreases during DE differentiation. DANCR may promote DE differentiation through modulating the activity of the WNT pathway.