title: Suppressing Pitx2 inhibits proliferation and promotes differentiation of iHepSCs.
abstract: Induced hepatic stem cells (iHepSCs) have great potential as donors for liver cell therapy due to their abilities for self-renewal and bi-potential differentiation. However, the molecular mechanism regulating proliferation and differentiation of iHepSCs is poorly understood. In this study, we provide evidence that the homeodomain transcription factor, Pitx2, is essential to maintain iHepSCs stem cell characteristics. Suppressing Pitx2 expression in iHepSCs by lentivirus mediated specific shRNA markedly reduced the expression of the hepatic stem cell-associated genes (Lgr5, EpCAM, and Sox9) with concomitant inhibition of proliferation by blocking the G1/S phase transition, and these phenotypic changes were reversed upon re-expression of Pitx2. Pitx2 knockdown also resulted in up-regulation of the p53-induced Cdk inhibitor p21, and down-regulation of its downstream effector CDK2-Cyclin E kinase complex. Furthermore, we observed that iHepSCs were more efficiently induced to differentiate into both hepatocytes and cholangiocytes when Pitx2 expression was suppressed, as compared to unmanipulated iHepSCs. These findings reveal that Pitx2 expression may be leveraged to control the status of iHepSCs during expansion in vitro to provide a strategy for further application of iHepSCs in liver cell therapy.
authors.affiliation: Department of Cell Biology, Center for Stem Cell and Medicine, Second Military Medical University, PR China.
authors.forename: Fei
authors.initials: F
authors.lastname: Chen
authors.affiliation: Department of Cell Biology, Center for Stem Cell and Medicine, Second Military Medical University, PR China.
authors.forename: Hao
authors.initials: H
authors.lastname: Yao
authors.affiliation: Department of Cell Biology, Center for Stem Cell and Medicine, Second Military Medical University, PR China.
authors.forename: Minjun
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Cell Biology, Center for Stem Cell and Medicine, Second Military Medical University, PR China.
authors.forename: Bing
authors.initials: B
authors.lastname: Yu
authors.affiliation: Department of Cell Biology, Center for Stem Cell and Medicine, Second Military Medical University, PR China.
authors.forename: Qinggui
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Department of Cell Biology, Center for Stem Cell and Medicine, Second Military Medical University, PR China.
authors.forename: Jianxiu
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Cell Biology, Center for Stem Cell and Medicine, Second Military Medical University, PR China.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: He
authors.affiliation: Department of Cell Biology, Center for Stem Cell and Medicine, Second Military Medical University, PR China. Electronic address: yphu@smmu.edu.cn.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Hu
mesh_terms: D000818:Animals; D059447:Cell Cycle Checkpoints / Q000235:genetics; D002454:Cell Differentiation / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D015536:Down-Regulation / Q000235:genetics; D055785:Gene Knockdown Techniques; D057809:HEK293 Cells; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000166:cytology*; D051379:Mice; D034741:RNA, Small Interfering / Q000235:genetics; D013234:Stem Cells / Q000166:cytology*; D014157:Transcription Factors / Q000172:deficiency* / Q000235:genetics*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D000097577:Homeobox Protein PITX2
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D018398:Homeodomain Proteins; D034741:RNA, Small Interfering; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D000097577:Homeobox Protein PITX2
keywords: Differentiation; Knockdown; Pitx2; Proliferation; iHepSCs