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Photo-click hydrogels for in situ differentiation of pancreatic progenitors from iPSCs

ABSTRACT: Induced pluripotent stem cells (iPSC) can be differentiated to cells in all three germ layers, as well as cells in the extraembryonic tissues. Efforts in iPSC differentiation into pancreatic progenitors in vitro have largely been focused on optimizing soluble growth cues in conventional two-dimensional (2D) culture, whereas the impact of three-dimensional (3D) matrix properties on the morphogenesis of iPSC remains elusive. In this work, we employ gelatin-based thiol-norbornene photo-click hydrogels for in situ 3D differentiation of human iPSCs into pancreatic progenitors (PP). Molecular analysis and single cell RNA-sequencing were utilized to elucidate on the distinct identities of subpopulations within the 2D and 3D differentiated cells. We found that, while established soluble cues led to predominately PP cells in 2D culture, differentiation of iPSCs using the same soluble factors led to prominent branching morphogenesis, ductal network formation, and generation of diverse endoderm populations. Through single-cell RNA-sequencing, we found that 3D differentiation resulted in enrichments of pan-endodermal cells and ductal cells. We further noted the emergence of a group of extraembryonic cells in 3D, which was absent in 2D differentiation. The unexpected emergence of extraembryonic cells in 3D was found to be associated with enrichment of Wnt and BMP signaling pathways, which may have contributed to the emergence of diverse cell populations. The expressions of PP signature genes PDX1 and NKX6.1 were restored through inhibition of Wnt signaling at the beginning of the posterior foregut stage. To our knowledge, this work established the first 3D hydrogel system for in situ differentiation of human iPSCs into PPs. Ongoing work focuses on enhancing pancreatic differentiation efficiency through modulating physicochemical properties of the iPSC-laden matrices.

ORGANISM(S): Homo sapiens

PROVIDER: GSE229058 | GEO | 2023/08/08

REPOSITORIES: GEO

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Project description:Emergence of induced pluripotent stem cells (iPSC) technology has paved novel routes for regenerative medicine. iPSCs offer the possibilities of disease modeling, drug toxicity studies as well as cell replacement therapies by autologous transplantation. Classical protocols of iPSC generation harness infection by retro- or lenti-viruses. Although such integrating viruses represent very robust tools for reprogramming, the presence of viral transgenes in iPSCs is deleterious as it holds the risk of insertional mutagenesis leading to malignant transformation. Moreover, remaining reprogramming transgenes have been shown to affect the differentiation potential of iPSCs. More recently, alternative protocols have been explored to derive transgene-free iPSC, including use of transposons, mRNA transfection, episomal plasmid transfection, and infection with non-integrating viruses such as Sendai virus. However, the utility of such protocols remains limited due to low efficiency and narrow range of cell specificity. In this study we aim at combining the robustness of lentiviral reprogramming with the high efficacy of Cre recombinase protein transduction to readily delete reprogramming transgenes from iPSCs. We demonstrate rapid generation of transgene-free human iPSCs by excising the loxP-flanked reprogramming cassette employing direct delivery of biologically active Cre protein. By genome-wide analysis and targeted differentiation towards the cardiomyocyte lineage, we show that transgene-free iPSCs do resemble more to human ESCs and has better differentiation potential than iPSCs before Cre transduction. Our study provides a simple, rapid and robust protocol for the generation of superior transgene-free iPSCs suitable for disease modeling, tissue engineering and cell replacement therapies. mRNA extracted from human Fibroblasts (AR1034ZIMA), human Embryonic Stem Cell line I3 (hES I3), three human induced Pluripotent Stem Cell clones 1, 1.2 and 1.4 (fl-ARiPS cl1, del-ARiPS cl 1.2, del-ARiPS cl1.4) has been hybridized on Illumina Human HT-12 (version 4 revision 2) arrays for genome wide expression analysis. Samples were run at least as duplicate technical replicates. Differential gene expression analysis has been performed on the grouped expression data with the human embryonic stem cells (hES I3) group as the reference.

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Photo-click hydrogels for in situ differentiation of pancreatic progenitors from iPSCs

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