ROCK Inhibition Accelerates Mesenchymal-to-Epithelial Transition and Improves Early Survival During Human Fibroblast Reprogramming.

The low efficiency in the production of induced pluripotent stem cell (iPSC) remains a major barrier to the widespread reprogramming applications in regenerative medicine and drug screening. Small molecules that modulate key signaling pathways offer a promising approach to overcome the reprogramming limitation. Here, we demonstrated that Thiazovivin (TZV), a selective Rho-associated coiled-coil kinase inhibitor, significantly increased human fibroblast reprogramming rate by approximately 1.4-fold (*p < 0.01). Treatment with TZV during the early phase of reprogramming enhanced colony formation, improved cell survival, and promoted the mesenchymal-to-epithelial transition (MET). Quantitative Real Time Polymerase Chain Reaction (RT-PCR) analysis revealed the downregulation of mesenchymal markers (N-cadherin, 52%; vimentin, 61%; p < 0.05) and upregulation of epithelial markers (E-cadherin, 165%; EpCAM, 95%; p < 0.05). Flow cytometry confirmed elevated expression of NANOG and TRA-1-60 pluripotency markers. Collectively, these findings suggest that TZV facilitates reprogramming through MET, offering a simple and effective strategy to enhance the efficiency and scalability of human iPSC generation.