Defined human PSC culture conditions robustly maintain human PSC pluripotency through Ca2+ signaling.

Human pluripotent stem cells (hPSCs) have significant potential for disease modeling and cell therapies. However, their clinical applicability is limited due to the need for undefined conditions for PSC cultivation, which increase the risk of immunogenicity, result in batch-to-batch variability and finite scalability. These limitations may be circumvented by xeno-free, defined culture conditions. However, biological processes that preserve robust, homogenous PSCs in defined conditions remain to be characterized. Here, we compared gene expression data from over 100 hPSC cell lines cultivated in undefined and defined culture conditions. Defined culture conditions significantly reduced inter-PSC line variability, highlighting the importance of standardization to minimize PSC biases. This variability is concurrent with decreased germ layer differentiation and increased expression of Ca2+-binding proteins. The significance of tightly controlled Ca2+ signaling in hPSC pluripotency in defined culture conditions was also confirmed. A deeper understanding of these processes may aid in standardizing defined hPSC culture conditions. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=174 HEIGHT=200 SRC="FIGDIR/small/552440v1_ufig1.gif" ALT="Figure 1"> View larger version (61K): org.highwire.dtl.DTLVardef@1e5729aorg.highwire.dtl.DTLVardef@c6fa28org.highwire.dtl.DTLVardef@1515b91org.highwire.dtl.DTLVardef@52c6b6_HPS_FORMAT_FIGEXP M_FIG C_FIG In BriefEidhof et al. compared gene expression array data obtained from more than 100 hPSC cell lines to study the biological differences between PSCs cultivated under defined and undefined culture conditions. HighlightsO_LIDefined culture conditions reduce inter-hPSC line variability. C_LIO_LIDefined conditions decrease the expression of germ layer differentiation markers. C_LIO_LICa2+ signaling associated genes capture specific hPSC states in defined conditions. C_LIO_LIHigh Ca2+ activity drives pluripotency, low Ca2+ activity drives differentiation. C_LI