Fig. 1

Human patient dermal fibroblasts reprogrammed into hiPSCs using mRNA–microRNA approach. a Reprogramming schematic for mRNA and microRNA transfections. b Bright-field images (10×) of human disease fibroblasts undergoing reprogramming. Day 0 fibroblasts displayed flat and elongated morphology typical of fibroblasts. Days 3 transfected cells show morphological changes including a rounded morphology and apoptosis, which are consistent with the reprogramming process. Days 10–15 cultures show colony formation, a key iPSC characteristic when cells are in contact with fibroblasts. Multipolar spindle-shaped fibroblast cells transitioning to a more compact cobblestone appearance at day 10, with early stem cell colonies arising by day 11–13 and expanding into well-circumscribed pluripotent stem cell colonies at day 15. Isolated stem cells maintain characteristic well-circumscribed morphology with minimal spontaneous differentiations through 20 + passages. iPSC, induced pluripotent stem cell; c Doubling time analyses indicate that all hiPSCs exhibit similar proliferation times representative of actively dividing cells