title: Microfluidic Screening Reveals Heparan Sulfate Enhances Human Mesenchymal Stem Cell Growth by Modulating Fibroblast Growth Factor-2 Transport.
abstract: Cost-effective expansion of human mesenchymal stem/stromal cells (hMSCs) remains a key challenge for their widespread clinical deployment. Fibroblast growth factor-2 (FGF-2) is a key hMSC mitogen often supplemented to increase hMSC growth rates. However, hMSCs also produce endogenous FGF-2, which critically interacts with cell surface heparan sulfate (HS). We assessed the interplay of FGF-2 with a heparan sulfate variant (HS8) engineered to bind FGF-2 and potentiate its activity. Bone marrow-derived hMSCs were screened in perfused microbioreactor arrays (MBAs), showing that HS8 (50 μg/ml) increased hMSC proliferation and cell number after 3 days, with an effect equivalent to FGF-2 (50 ng/ml). In combination, the effects of HS8 and FGF-2 were additive. Differential cell responses, from upstream to downstream culture chambers under constant flow of media in the MBA, provided insights into modulation of FGF-2 transport by HS8. HS8 treatment induced proliferation mainly in the downstream chambers, suggesting a requirement for endogenous FGF-2 accumulation, whereas responses to FGF-2 occurred primarily in the upstream chambers. Adding HS8 along with FGF-2, however, maximized the range of FGF-2 effectiveness. Measurements of FGF-2 in static cultures then revealed that this was because HS8 caused increased endogenous FGF-2 production and liberated FGF-2 from the cell surface into the supernatant. HS8 also sustained levels of supplemented FGF-2 available over 3 days. These results suggest HS8 enhances hMSC proliferation and expansion by leveraging endogenous FGF-2 production and maximizing the effect of supplemented FGF-2. This is an exciting strategy for cost-effective expansion of hMSCs. Stem Cells Translational Medicine 2017;6:1178-1190.
authors.affiliation: Institute of Medical Biology, Agency for Science Technology and Research (A*STAR), Singapore.
authors.forename: Drew M
authors.initials: DM
authors.lastname: Titmarsh
authors.affiliation: Institute of Medical Biology, Agency for Science Technology and Research (A*STAR), Singapore.
authors.forename: Clarissa L L
authors.initials: CL
authors.lastname: Tan
authors.affiliation: Australian Institute for Bioengineering & Nanotechnology.
authors.forename: Nick R
authors.initials: NR
authors.lastname: Glass
authors.affiliation: Institute of Medical Biology, Agency for Science Technology and Research (A*STAR), Singapore.|Lee Kong Chian School of Medicine, Nanyang Technological University-Imperial College London, Singapore.
authors.forename: Victor
authors.initials: V
authors.lastname: Nurcombe
authors.affiliation: Australian Institute for Bioengineering & Nanotechnology.|School of Chemical Engineering, The University of Queensland, St. Lucia, Queensland, Australia.|Biomedical Manufacturing, Manufacturing Flagship, CSIRO, Clayton, Victoria, Australia.
authors.forename: Justin J
authors.initials: JJ
authors.lastname: Cooper-White
authors.affiliation: Institute of Medical Biology, Agency for Science Technology and Research (A*STAR), Singapore.|Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Simon M
authors.initials: SM
authors.lastname: Cool
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism*; D006497:Heparan Sulfate / Q000494:pharmacology*; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000378:metabolism*; D044085:Microfluidics; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D016222:Fibroblast Growth Factor 2; D006497:Heparan Sulfate
keywords: Fibroblast growth factor 2; Heparan sulfate; Mesenchymal stromal cells; Microfluidics