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Although lineage reprogramming from one cell type to another is becoming a breakthrough technology for cell-based therapy, several limitations remain to be overcome, including the low conversion efficiency and subtype specificity. To address these, many studies have been conducted using genetics, chemistry, physics, and cell biology to control transcriptional networks, signaling cascades, and epigenetic modifications during reprogramming. Here, we summarize recent advances in cellular reprogramming and discuss future directions. [ABSTRACT FROM AUTHOR]

Although lineage reprogramming from one cell type to another is becoming a breakthrough technology for cell-based therapy, several limitations remain to be overcome, including the low conversion efficiency and subtype specificity. To address these, many studies have been conducted using genetics, chemistry, physics, and cell biology to control transcriptional networks, signaling cascades, and epigenetic modifications during reprogramming. Here, we summarize recent advances in cellular reprogramming and discuss future directions.

Ionizing radiation causes not only targeted effects in cells that have been directly irradiated but also non-targeted effects in several cell generations after initial exposure. Recent studies suggest that radiation can enrich for a population of stem cells, derived from differentiated cells, through cellular reprogramming. Here, we elucidate the effect of irradiation on reprogramming, subjected to two different responses, using an induced pluripotent stem cell (iPSC) model. iPSCs were generated from non-irradiated cells, directly-irradiated cells, or cells subsequently generated after initial radiation exposure. We found that direct irradiation negatively affected iPSC induction in a dose-dependent manner. However, in the post-irradiated group, after five subsequent generations, cells became increasingly sensitive to the induction of reprogramming compared to that in non-irradiated cells as observed by an increased number of Tra1-81-stained colonies as well as enhanced alkaline phosphatase andOct4promoter activity. Comparative analysis, based on reducing the number of defined factors utilized for reprogramming, also revealed enhanced efficiency of iPSC generation in post-irradiated cells. Furthermore, the phenotypic acquisition of characteristics of pluripotent stem cells was observed in all resulting iPSC lines, as shown by morphology, the expression of pluripotent markers, DNA methylation patterns of pluripotency genes, a normal diploid karyotype, and teratoma formation. Overall, these results suggested that reprogramming capability might be differentially modulated by altered radiation-induced responses. Our findings provide that susceptibility to reprogramming in somatic cells might be improved by the delayed effects of non-targeted response, and contribute to a better understanding of the biological effects of radiation exposure. [ABSTRACT FROM PUBLISHER]

Type 1 diabetes (T1D) is a disease that is typically associated with multigenetic changes as well as environmental triggers. Disease-specific induced pluripotent stem cells (iPSCs) are preferable cell sources to study T1D, as they are derived from patient cells and therefore capture the disease genotype in a stem cell line. The purpose of this study was to generate integration-free iPSCs from adult skin fibroblasts with T1D. iPSCs were generated by transfection of synthetic mRNAs encoding transcription factors OCT4, SOX2, KLF4, c-MYC, and LIN28. Phase-contrast microscopy, immunocytochemistry, karyotyping, bisulfite genomic sequencing, reverse transcription-polymerase chain reaction, and teratoma formation assay were used to determine reprogramming efficiency, pluripotency, and differentiation potential. Following 18 consecutive days of synthetic mRNA transfections, the T1D patient skin fibroblasts underwent morphological changes, and the aggregated clumps exhibited a human embryonic stem cell (ESC)-like morphology with a high nucleus/cytoplasm ratio. Highly efficient generation of iPSCs was achieved using the mRNA reprogramming approach. The disease-specific iPSCs expressed pluripotency markers, maintained a normal karyotype, and formed teratomas containing tissues representative of the three germ layers when injected into immune-deficient mice. Of interest, the iPSCs showed upregulations of pancreas-specific microRNAs, compared with parental fibroblasts. These data indicate that T1D patient skin fibroblasts can be reprogrammed to pluripotency using a synthetic mRNA approach. These cells can serve as a useful tool for the identification of genes that are involved in autoimmune reactions as well as generating patient-matched β-cells for cell-based therapy.