Short-Term Rho-Associated Kinase Inhibitor Treatment Accelerates Primary Keratinocyte Growth Without Affecting the Stem Cell Population

The study investigated the impact of short-term (6 days) Rho-associated kinase inhibitor (ROCKi) treatment on cultured primary keratinocytes, including keratinocyte stem cells (KSCs). The treatment resulted in a 15-fold increase in colony-forming efficiency, increased expression of proliferation markers, mitochondrial mass, and distinct gene expression in treated cells compared to untreated cells. However, these properties reversed and became almost indistinguishable between treated and untreated cells after discontinuation of ROCKi treatment. Single-cell transcriptome analysis further confirmed that stem cells were not affected after the short-term ROCKi treatment. The study concluded that short-term ROCKi treatment can transiently and reversibly accelerate KSC proliferation without exhausting the KSC population nor affecting their characteristics, presenting a safe avenue for the use of ROCKi in in vitro primary keratinocyte culture for clinical applications.