title: Extracellular regulated protein kinases 1/2 phosphorylation is required for hepatic differentiation of human umbilical cord-derived mesenchymal stem cells.
abstract: Mesenchymal stem cells (MSCs) have the capacity to restore liver function by differentiating into hepatocyte like cells. However, the underlying mechanisms are not well understood. Here, we have investigated the signals involved in the hepatic differentiation of human umbilical cord-derived mesenchymal stem cells (hUCMSCs). hUCMSCs were treated with mouse fetal liver-conditioned medium (FLCM) to induce hepatic differentiation. Flow cytometry, reverse transcription PCR, real-time PCR, immunocytochemistry, and polymerase chain reaction (PCR) array were used to detect the expression of MSC- and hepotocyte-specific markers in FLCM-treated hUCMSCs. Urea production and cytochrome P450 3A4 (CYP3A4) activity were used as indicators to evaluate liver cell characteristics. Raf/mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) was analyzed in hUCMSCs by Western blotting. Following FLCM treatment, expression of MSC-specific markers decreased, while hepatocyte-specific gene expression was increased. Urea production, albumin secretion, glycogen storage, and CYP3A4 activity were significantly enhanced in FLCM-treated cells. In addition, ERK1/2 phosphorylation was increased in a time-dependent manner through Raf/MEK/ERK pathway, and phosphorylation was sustained at a high level during hepatic induction. Inhibition of ERK1/2 activation by U0126 (an ERK1/2 inhibitor) and pFLAG-CMV-ERK1(K71R) (negative mutant of ERK1) reversed the expression of liver-specific genes in hUCMSCs and affected hepatic function significantly. In summary, this work shows that ERK1/2 phosphorylation plays an important role in inducing hepatic differentiation of hUCMSCs in FLCM.
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Yongmin
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Clinical Laboratory of Nantong Tumour Hospital, Nantong, Jiangsu 226000, P.R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Sun
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Limin
authors.initials: L
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Zixuan
authors.initials: Z
authors.lastname: Sun
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China icls@ujs.edu.cn 1stmmm1st@163.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Qian
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhu
authors.affiliation: Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China The Affiliated Hospital, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China icls@ujs.edu.cn 1stmmm1st@163.com.
authors.forename: Wenrong
authors.initials: W
authors.lastname: Xu
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000494:pharmacology; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D005312:Fetal Blood / Q000166:cytology*; D022781:Hepatocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology*; D013997:Time Factors; D014508:Urea / Q000378:metabolism; D048490:raf Kinases / Q000378:metabolism
chemical_list: D017077:Culture Media, Conditioned; D014508:Urea; D051544:Cytochrome P-450 CYP3A; D048490:raf Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases
keywords: ERK1/2; fetal liver-conditioned medium; hepatocytes; umbilical cord-derived mesenchymal stem cell