Induced pluripotent stem cells can be reprogrammed from human umbilical cord mesenchymal cells by six transcription factors

Abstract

Objective To establish and identify the induced pluripotent stem cell(iPSC) line reprogrammed from human umbilical cord mesenchymal cells(HuMSCs). Methods HuMSCs were cultured by adhesion method, and OCT4, SOX2, KLF4, c-Myc, NANOG, LIN-28 were transfected into HuMSCs with lentiviral victor to reprogramme HuMSCs into iPSC.Morphological observation, pluripotency genes(SOX2, TDGF1, THY-1, OCT4, REX1 and TERF1) expression, alkaline phosphatase detection, karyotype analysis, embryonic stem cells(ESC) specific proteins(NANOG, OCT4, SSEA-4, TRA-1-81) immunofluorescence staining, differentiated into teratomas in vivo(inject the iPSC into SCID mice) and embryniod bodies in vitro were performed to exam the pluripotency of the iPSC. Results Four days after being infected by lentivirus, the HuMSCs became round-shape; 10 days after infection, some embryonic stem(ESC)-like colonies appeared.Fourteen days after infection, picked up the regularly shaped colonies and cultured several passages.About 1.25% HuMSCs were reprogrammed into iPSC.The iPSC presented clone-like growth like ESC.All the cells were positive to alkaline phosphatase staining and expressed the pluripotency genes.The iPSC also expressed the ESC specific proteins, and karyotype analysis showed normal chromosome caryotype(46, XY). Furthermore, the iPSC could form embryoid bodies in vitro, expressed alpha fetoprotein(AFP), smooth muscle actin(SMA) and β-tubulin.The iPSC could alsoform teratomas in vivo. Conclusion OCT4, SOX2, KLF4, c-Myc, NANOG, LIN-28 can reprogram HuMSCs into iPSC efficiently. Key words: Umbilical cord mesenchymal stem cells; Induced pluripotent stem cells; Transcription factor; Lentiviral vector