Chemical Control of Human Pluripotent Stem Cell Renewal

Background and Aim: The large-scale and cost-effective production ofquality-controlled human pluripotent stem cells (hPSCs including humanembryonic stem (ES) cells and induced pluripotent stem (iPS) cells) foruse in cell therapy and drug discovery would ideally require a chemicallydefined xenobiotic-free culture system. Towards the development ofsuch a system, costs associated with the use of recombinant proteinsas supplements in basal culture media and culture substrate need to bereduced.Methods: In a hypothesis-driven small chemical library screeningapproach following prediction of hPSC self-renewal mechanisms basedon comprehensive genome-wide gene expression analysis, we haveidentified novel signaling cascades and chemical compounds thatregulate hPSC self-renewal and differentiation. Utilizing the chemicalcompounds, we have developed a growth-factor-free culture mediumthat uses just three chemical compounds and a lower number ofrecombinant proteins than used in a commercially available medium. Inaddition, by utilizing polymers, we have developed protein substrate-free3D suspension culture method for hPSCs.Results: In the culture system, all examined human ES and iPS cell linescould be expanded robustly. These cells maintained their undifferentiatedstate markers expression and differentiation capacity to derive all majorcell types without modification of well-established differentiationmethods. Furthermore, the culture system could support the generationof iPS cell derivation from either human dermal fibroblasts or peripheralblood mononuclear cells.Conclusion: Utilizing these compounds and polymers, we have beendeveloping defined hPSC culture system for their applications. Ourfindings should facilitate the ongoing development of a completely xenofree,chemically defined, synthetic culture system for hPSCs.

Keywords:

Human pluripotent stem cell , ES cell , iPS cell , Chemical compound , Polymer , Culture system