Short-term Rho-associated kinase inhibitor treatment accelerates primary keratinocyte growth while preserving stem cell characteristics

Somatic stem cells can be cultured in-vitro and are attractive for cell and gene therapies, but their slow growth in in-vitro culture affects survival and stemness and hinders clinical applications. Rho-associated kinase inhibitor (ROCKi) has been used to overcome these obstacles. However, it risks changing the characteristics of stem cells. We found that primary keratinocyte stem cells (KSCs) cultured with the ROCKi Y-27632 for six days exhibited rapid proliferation while maintaining the ability to differentiate. Importantly, after discontinuation of ROCKi treatment, KSC numbers and characteristics were indistinguishable from those in non-treated cultures. We further confirmed that ROCKi treatment resulted in the activation of AKT and ERK pathways, which could support cell survival and proliferation in keratinocytes. We thus concluded that accelerating keratinocyte expansion with short-term ROCKi treatment does not exhaust KSCs’ self-renewal and differentiation capacities, presenting a safe avenue for clinical applications.