Cell-permeable Oct4 gene delivery enhances stem cell-like properties of mouse embryonic fibroblasts

Abstract

Direct conversion of one cell type into another is a trans-differentiation process. Recent advances in fibroblast research revealed that epithelial cells can give rise to fibroblasts by epithelial-mesenchymal transition. Conversely, fibroblasts can also give rise to epithelia by undergoing a mes-enchymal to epithelial transition. To elicit stem cell-like properties in fibroblasts, the Oct4 transcription factor acts as a master transcriptional regulator for reprogramming somatic cells. Notably, the production of gene complexes with cell-permeable peptides, such as low-molecular-weight prota-mine (LMWP), was proposed to induce reprogramming without cytotoxicity and genomic muta-tion. We designed a complex with non-cytotoxic LMWP to prevent the degradation of Oct4 and revealed that the positively charged cell-permeable LMWP helped condense the size of the Oct4-LMWP complexes (1:5 N:P ratio). When the Oct4-LMWP complex was delivered into mouse embryonic fibroblasts (MEFs), stemness-related gene expression increased while fibroblast intrinsic properties decreased. We believe that the Oct4-LMWP complex developed in this study can be used to reprogram terminally differentiated somatic cells or convert them into stem cell-like cells without risk of cell death, improving the stemness level and stability of existing direct conversion tech-niques.