title: Reprogramming human retinal pigmented epithelial cells to neurons using recombinant proteins.
abstract: Somatic cells can be reprogrammed to an altered lineage by overexpressing specific transcription factors. To avoid introducing exogenous genetic material into the genome of host cells, cell-penetrating peptides can be used to deliver transcription factors into cells for reprogramming. Position-dependent C-end rule (CendR) cell- and tissue-penetrating peptides provide an alternative to the conventional cell-penetrating peptides, such as polyarginine. In this study, we used a prototypic, already active CendR peptide, RPARPAR, to deliver the transcription factor SOX2 to retinal pigmented epithelial (RPE) cells. We demonstrated that RPE cells can be directly reprogrammed to a neuronal fate by introduction of SOX2. Resulting neuronal cells expressed neuronal marker mRNAs and proteins and downregulated expression of RPE markers. Cells produced extensive neurites and developed synaptic machinery capable of dye uptake after depolarization with potassium. The RPARPAR-mediated delivery of SOX2 alone was sufficient to allow cell lineage reprogramming of both fetal and stem cell-derived RPE cells to become functional neurons.
authors.affiliation: Center for Stem Cell Biology and Engineering and Center for Nanomedicine and Sanford-Burnham Medical Research Institute, University of California Santa Barbara, Santa Barbara, California, USA; Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA.
authors.forename: Qirui
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Center for Stem Cell Biology and Engineering and Center for Nanomedicine and Sanford-Burnham Medical Research Institute, University of California Santa Barbara, Santa Barbara, California, USA; Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA.
authors.forename: Renwei
authors.initials: R
authors.lastname: Chen
authors.affiliation: Center for Stem Cell Biology and Engineering and Center for Nanomedicine and Sanford-Burnham Medical Research Institute, University of California Santa Barbara, Santa Barbara, California, USA; Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA.
authors.forename: Tambet
authors.initials: T
authors.lastname: Teesalu
authors.affiliation: Center for Stem Cell Biology and Engineering and Center for Nanomedicine and Sanford-Burnham Medical Research Institute, University of California Santa Barbara, Santa Barbara, California, USA; Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA.
authors.forename: Erkki
authors.initials: E
authors.lastname: Ruoslahti
authors.affiliation: Center for Stem Cell Biology and Engineering and Center for Nanomedicine and Sanford-Burnham Medical Research Institute, University of California Santa Barbara, Santa Barbara, California, USA; Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, USA clegg@lifesci.ucsb.edu.
authors.forename: Dennis O
authors.initials: DO
authors.lastname: Clegg
mesh_terms: D000943:Antigens, Differentiation / Q000096:biosynthesis / Q000235:genetics; D065150:Cellular Reprogramming; D006801:Humans; D016501:Neurites / Q000378:metabolism*; D055213:Retinal Pigment Epithelium / Q000166:cytology / Q000378:metabolism; D055748:SOXB1 Transcription Factors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000943:Antigens, Differentiation; C527782:SOX2 protein, human; D055748:SOXB1 Transcription Factors
keywords: Cell penetrating peptide; Lineage reprogramming; Neuron; Protein transduction; Retinal pigmented epithelium