Samantha F H De Witte1, Fleur S Peters1, Ana Merino1, Sander S Korevaar1, Joyce B J Van Meurs2, Lisa O'Flynn3, Steve J Elliman3, Philip N Newsome4, Karin Boer1, Carla C Baan1, Martin J Hoogduijn5. 1. Nephrology and Transplantation. 2. Endocrinology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands. 3. Orbsen Therapeutics Ltd., Galway, Ireland. 4. National Institute for Health Research Biomedical Research Centre at University Hospitals Birmingham National Health Service, Foundation Trust and the University of Birmingham; Centre for Liver Research, Institute of Immunology and Immunotherapy, University of Birmingham; Liver Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom. 5. Nephrology and Transplantation. Electronic address: m.hoogduijn@erasmusmc.nl.
Abstract
BACKGROUND: Mesenchymal stromal cells (MSCs) are studied for their immunotherapeutic potential. Prior to therapeutic use, MSCs are culture expanded to obtain the required cell numbers and, to improve their efficacy, MSCs may be primed in vitro. Culture expansion and priming induce phenotypical and functional changes in MSCs and thus standardisation and quality control measurements come in need. We investigated the impact of priming and culturing on MSC DNA methylation and examined the use of epigenetic profiling as a quality control tool. METHODS: Human umbilical cord-derived MSCs (ucMSCs) were cultured for 3 days with interferon (IFN)γ, transforming growth factor (TGF)β or a multi-factor combination (MC; IFNγ, TGFβ and retinoic acid). In addition, ucMSCs were culture expanded for 14 days. Phenotypical changes and T-cell proliferation inhibition capacity were examined. Genome-wide DNA methylation was measured with Infinium MethylationEPIC Beadchip. RESULTS: Upon priming, ucMSCs exhibited a different immunophenotype and ucMSC(IFNγ) and ucMSC(MC) had an increased capacity to inhibit T-cell proliferation. DNA methylation patterns were minimally affected by priming, with only one significantly differentially methylated site (DMS) in IFNγ- and MC-primed ucMSCs associated with autophagy activity. In contrast, 14 days after culture expansion, ucMSCs displayed minor phenotypical and functional changes but showed >4000 significantly DMSs, mostly concerning genes involved in membrane composition, cell adhesion and transmembrane signalling. DISCUSSION: These data show that DNA methylation of MSCs is only marginally affected by priming, whereas culture expansion and subsequent increased cellular interactions have a large impact on methylation. On account of this study, we suggest that DNA methylation analysis is a useful quality control tool for culture expanded therapeutic MSCs.
BACKGROUND: Mesenchymal stromal cells (MSCs) are studied for their immunotherapeutic potential. Prior to therapeutic use, MSCs are culture expanded to obtain the required cell numbers and, to improve their efficacy, MSCs may be primed in vitro. Culture expansion and priming induce phenotypical and functional changes in MSCs and thus standardisation and quality control measurements come in need. We investigated the impact of priming and culturing on MSC DNA methylation and examined the use of epigenetic profiling as a quality control tool. METHODS:Human umbilical cord-derived MSCs (ucMSCs) were cultured for 3 days with interferon (IFN)γ, transforming growth factor (TGF)β or a multi-factor combination (MC; IFNγ, TGFβ and retinoic acid). In addition, ucMSCs were culture expanded for 14 days. Phenotypical changes and T-cell proliferation inhibition capacity were examined. Genome-wide DNA methylation was measured with Infinium MethylationEPIC Beadchip. RESULTS: Upon priming, ucMSCs exhibited a different immunophenotype and ucMSC(IFNγ) and ucMSC(MC) had an increased capacity to inhibit T-cell proliferation. DNA methylation patterns were minimally affected by priming, with only one significantly differentially methylated site (DMS) in IFNγ- and MC-primed ucMSCs associated with autophagy activity. In contrast, 14 days after culture expansion, ucMSCs displayed minor phenotypical and functional changes but showed >4000 significantly DMSs, mostly concerning genes involved in membrane composition, cell adhesion and transmembrane signalling. DISCUSSION: These data show that DNA methylation of MSCs is only marginally affected by priming, whereas culture expansion and subsequent increased cellular interactions have a large impact on methylation. On account of this study, we suggest that DNA methylation analysis is a useful quality control tool for culture expanded therapeutic MSCs.