iSTEM is a completely defined cell culture medium for deriving, maintaining, and propagating mouse embryonic stem (ES) cells. This media formulation captures mouse ES cells in their basal state by blocking the inductive pathways of differentiation with selective small molecule inhibitors. The medium contains three small molecule inhibitors that block differentiation-inducing signals and promote cell survival, enabling maintenance of pluripotency without the need for additional stimulatory cytokines. iSTEM medium can also be used to derive mouse ES lines from strains that have proven refractory to ES cell derivation under standard conditions (1).
Mouse ES cells cultured in iSTEM medium continually expand at a doubling rate that is comparable to that of cells cultured in the presence of Leukemia Inhibitory Factor (LIF) and serum/Bone Morphogenetic Protein (BMP) (1). In addition, culture in iSTEM medium enhances clonogenicity; a higher frequency of pluripotent colonies are established after single cell deposition.