title: Reversible Immortalization Enables Seamless Transdifferentiation of Primary Fibroblasts into Other Lineage Cells.
abstract: Fibroblasts can be transdifferentiated directly into other somatic cells such as cardiomyocytes, hematopoietic cells, and neurons. An advantage of somatic cell differentiation without first generating induced pluripotent stem cells (iPSCs) is that it avoids contamination of the differentiated cells with residual iPSCs, which may cause teratoma. However, since primary fibroblasts from biopsy undergo senescence during repeated culture, it may be difficult to grow transdifferentiated cells in sufficient numbers for future therapeutic purposes. To circumvent this problem, we reversibly immortalized primary fibroblasts by using the piggyBac transposon to deliver the human telomerase reverse transcriptase (hTERT) gene hTERT plus SV40 Large T. Both approaches enabled fibroblasts to grow continuously without senescence, and neither caused teratoma formation in immunodeficient mice. However, fibroblasts immortalized with hTERT plus SV40 large T antigen accumulated chromosomal rearrangements, whereas fibroblasts immortalized with hTERT retained the normal karyotype. To transdifferentiate hTERT-immortalized fibroblasts into other somatic lineage cells, we transiently transfected them with episomal OCT4 and cultured them under neural cell growth condition with transposase to remove the transposon. Tripotent neural progenitor cells were seamlessly and efficiently generated. Thus, reversible immortalization of primary fibroblasts with hTERT will allow potential autologous cell-based therapeutics that bypass and simulate iPSC generation.
authors.affiliation: 1 Department of Medicine, University of California , San Francisco, California.
authors.forename: Fei
authors.initials: F
authors.lastname: Xie
authors.affiliation: 2 Departments of Oral and Maxillofacial Surgery, University of California San Francisco , San Francisco, California.
authors.forename: Kerui
authors.initials: K
authors.lastname: Gong
authors.affiliation: 3 Gladstone Institute of Cardiovascular Disease , San Francisco, California.
authors.forename: Ke
authors.initials: K
authors.lastname: Li
authors.affiliation: 3 Gladstone Institute of Cardiovascular Disease , San Francisco, California.
authors.forename: Mingliang
authors.initials: M
authors.lastname: Zhang
authors.affiliation: 1 Department of Medicine, University of California , San Francisco, California.
authors.forename: Judy C
authors.initials: JC
authors.lastname: Chang
authors.affiliation: 4 The Department of Cardiology, the Eighth People's Hospital of Shanghai , Shanghai, China .
authors.forename: Shizhong
authors.initials: S
authors.lastname: Jiang
authors.affiliation: 1 Department of Medicine, University of California , San Francisco, California.
authors.forename: Lin
authors.initials: L
authors.lastname: Ye
authors.affiliation: 1 Department of Medicine, University of California , San Francisco, California.|5 Department of Laboratory Medicine, University of California , San Francisco, California.
authors.forename: Jiaming
authors.initials: J
authors.lastname: Wang
authors.affiliation: 1 Department of Medicine, University of California , San Francisco, California.|6 State Key Laboratory of Medical Genomics, Shanghai Institute of Hematology, Rui Jin Hospital, School of Medicine, Shanghai Jiao Tong University , Shanghai, China .
authors.forename: Yuting
authors.initials: Y
authors.lastname: Tan
authors.affiliation: 1 Department of Medicine, University of California , San Francisco, California.|5 Department of Laboratory Medicine, University of California , San Francisco, California.|7 Institute for Human Genetics, University of California , San Francisco, California.
authors.forename: Yuet Wai
authors.initials: YW
authors.lastname: Kan
mesh_terms: D000818:Animals; D063646:Carcinogenesis / Q000473:pathology; D002461:Cell Line, Transformed; D019070:Cell Lineage; D054338:Cell Transdifferentiation; D003114:Colony-Forming Units Assay; D004251:DNA Transposable Elements / Q000235:genetics; D005347:Fibroblasts / Q000166:cytology*; D006801:Humans; D007621:Karyotyping; D016513:Mice, SCID; D058953:Neural Stem Cells / Q000166:cytology; D014162:Transfection
chemical_list: D004251:DNA Transposable Elements