title: The cytotoxic and immunogenic hurdles associated with non-viral mRNA-mediated reprogramming of human fibroblasts.
abstract: Delivery of reprogramming factor-encoding mRNAs by means of lipofection in somatic cells is a desirable method for deriving integration-free iPSCs. However, the lack of reproducibility implies there are major hurdles to overcome before this protocol becomes universally accepted. This study demonstrates the functionality of our in-house synthesized mRNAs expressing the reprogramming factors (OCT4, SOX2, KLF4, c-MYC) within the nucleus of human fibroblasts. However, upon repeated transfections, the mRNAs induced severe loss of cell viability as demonstrated by MTT cytotoxicity assays. Microarray-derived transcriptome data revealed that the poor cell survival was mainly due to the innate immune response triggered by the exogenous mRNAs. We validated the influence of mRNA transfection on key immune response-associated transcript levels, including IFNB1, RIG-I, PKR, IL12A, IRF7 and CCL5, by quantitative real-time PCR and directly compared these with the levels induced by other methods previously published to mediate reprogramming in somatic cells. Finally, we evaluated chemical compounds (B18R, chloroquine, TSA, Pepinh-TRIF, Pepinh-MYD), known for their ability to suppress cellular innate immune responses. However, none of these had the desired effect. The data presented here should provide the basis for further investigations into other immunosuppressing strategies that might facilitate efficient mRNA-mediated cellular reprogramming in human cells.
authors.affiliation: Molecular Embryology and Aging Group, Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Ihnestr. 63-73, 14195 Berlin, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Drews
authors.forename: Geertrui
authors.initials: G
authors.lastname: Tavernier
authors.forename: Joseph
authors.initials: J
authors.lastname: Demeester
authors.forename: Hans
authors.initials: H
authors.lastname: Lehrach
authors.forename: Stefaan C
authors.initials: SC
authors.lastname: De Smedt
authors.forename: Joanna
authors.initials: J
authors.lastname: Rejman
authors.forename: James
authors.initials: J
authors.lastname: Adjaye
mesh_terms: D002470:Cell Survival; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D007113:Immunity, Innate; D000090062:Kruppel-Like Factor 4; D008081:Liposomes; D012333:RNA, Messenger / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: C000715467:KLF4 protein, human; D000090062:Kruppel-Like Factor 4; D008081:Liposomes; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins