title: Whole-genome sequencing identifies genetic variances in culture-expanded human mesenchymal stem cells.
abstract: Culture-expanded human mesenchymal stem cells (MSCs) are increasingly used in clinics, yet full characterization of the genomic compositions of these cells is lacking. We present a whole-genome investigation on the genetic dynamics of cultured MSCs under ex vivo establishment (passage 1 [p1]) and serial expansion (p8 and p13). We detected no significant changes in copy-number alterations (CNAs) and low levels of single-nucleotide changes (SNCs) until p8. Strikingly, a significant number (677) of SNCs were found in p13 MSCs. Using a sensitive Droplet Digital PCR assay, we tested the nonsynonymous SNCs detected by whole-genome sequencing and found that they were preexisting low-frequency mutations in uncultured mononuclear cells (∼0.01%) and early-passage MSCs (0.1%-1% at p1 and p8) but reached 17%-36% in p13. Our data demonstrate that human MSCs maintain a stable genomic composition in the early stages of ex vivo culture but are subject to clonal growth upon extended expansion.
authors.affiliation: Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Cai
authors.affiliation: Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xuexia
authors.initials: X
authors.lastname: Miao
authors.affiliation: Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yueying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Predoctoral Training Program in Human Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Stem Cell Program, Institute for Cell Engineering, and Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Cory
authors.initials: C
authors.lastname: Smith
authors.affiliation: Stem Cell Program, Institute for Cell Engineering, and Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Kitman
authors.initials: K
authors.lastname: Tsang
authors.affiliation: Predoctoral Training Program in Human Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Stem Cell Program, Institute for Cell Engineering, and Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Electronic address: lcheng2@jhmi.edu.
authors.forename: Linzhao
authors.initials: L
authors.lastname: Cheng
authors.affiliation: Laboratory of Genome Variations and Precision Bio-Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: wangqf@big.ac.cn.
authors.forename: Qian-Fei
authors.initials: QF
authors.lastname: Wang
mesh_terms: D000328:Adult; D001854:Bone Marrow Cells / Q000166:cytology; D002478:Cells, Cultured; D056915:DNA Copy Number Variations; D015894:Genome, Human; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D017422:Sequence Analysis, DNA