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Facile bead-to-bead cell-transfer method for serial subculture and large-scale expansion of human mesenchymal stem cells in bioreactors
Shangwu Chen, et al., STEM CELLS Translational Medicine

Large-scale expansion of human mesenchymal stem cells (hMSCs) in stirred tank bioreactors is challenging because hMSCs have limited proliferation potential and are sensitive to damage from enzyme treatment. The authors first discovered that a culture medium with nucleosides significantly promoted the proliferation of hMSCs in 2D and microcarrier-based suspension culture. Subsequently the authors developed a bead-to-bead cell transfer process with intermittent agitation for cell culture scale-up in bioreactors, which maintained the proliferation, viability, and normal phenotype of hMSCs. The bead-to-bead cell transfer has great potential for large-scale manufacturing of hMSCs for cell therapy.

Fluid shear stress promotes embryonic stem cell pluripotency via interplay between β-catenin and vinculin in bioreactor culture
Suman C. Nath, et al., STEM CELLS

Fluid shear stress generated in bioreactors can modulate cell behavior, pluripotency, and differentiation capability. This study reveals that fluid shear stress upregulates murine embryonic stem cell pluripotency, which obviates the necessity of adding leukemia inhibitory factor in bioreactor culture. This phenome-non has been termed as mechanopluripotency. Translocation ofβ-catenin to the nucleus is the key to mechanopluripotency in bioreactor culture. In addition, adherens junction-associated vinculin is another important factor as vinculin gene disruption results in abrogation of mechanopluripotency in bioreactor culture.