Optimization and development of better defined culture methods for human embryonic and induced pluripotent stem cells (hESCs
and hiPSCs) will provide an invaluable contribution to the field of regenerative medicine. However, one problem is the vulnerability
of hESCs and hiPSCs to apoptosis that causes a low plating efficiency upon passaging. Herein, we have developed a novel hESCs
and hiPSCs culture technique that uses ROCK inhibitor (ROCKi) Y-27632 (10 µM) in Matrigel-coated dishes in both serum- and
feeder-free culture conditions. This increases plating efficiency during enzymatic and mechanical passaging as compared to
its presence solely in culture medium. Under these conditions, hESCs (three lines) and hiPSCs (two lines) retain their typical
morphology, a stable karyotype, express pluripotency markers and have the potential to differentiate into derivatives of all
three germ layers after long-term culture. Real-time RT-PCR analysis of stemness-related integrins (αV, α6, and β1) has demonstrated
that their expression increases in the presence of ROCKi. Similar plating efficiencies have been obtained in both hESCs and
hiPSCs with a lower concentration of Y-27632 (800 nM) and another ROCKi (HA-1077/Fasudil), thus ruling out the non-specific
effects of Y-27632. These results show that addition of ROCKi in the extracellular matrix can increase the plating efficiency
of hESCs and hiPSCs during passaging of clusters. This is due not only to an anti-apoptotic effect, but also to an increase
in the ECM-cells interaction. Therefore, we believe this method will be useful for both current and future applications of
these pluripotent stem cells.
Keywords Human embryonic stem cells - Human induced pluripotent stem cells - ROCK inhibitor - Passaging