Project description:Induced pluripotent stem cells (iPSCs) derived from somatic cells of patients by viral vector-mediated factor transduction represent a powerful tool for biomedical research and may provide a source for cell replacement therapies. However, the proviruses encoding the reprogramming factors represent a major limitation of the current technology because even low vector expression may alter the differentiation potential of the iPSCs and induce malignant transformation. Here we show that fibroblasts from five patients with idiopathic Parkinson’s disease (PD) can be efficiently reprogrammed into hiPSCs and subsequently differentiated into dopaminergic neurons. Moreover, we derived PD specific hiPSCs free of reprogramming factors using Cre-recombinase excisable viruses. Upon factor deletion these cells maintain a pluripotent state and intact karyotype. Importantly, these factor-free hiPSCs show a global gene expression profile, which is more closely related to hESCs than to hiPSCs carrying the transgenes. Our results indicate that residual transgene expression in conventional virus-carrying hiPSCs can affect their molecular characteristics and that factor-free hiPSCs therefore represent a more suitable source of cells for modeling of human disease.
Project description:We have generated human induced Pluripotent Stem cells (hiPSc) using Retroviral virus-mediated delivery of reprogramming factors. hiPSc lines have been screened using SNP array to assess chromosomal stability (alongside the fibroblast lines from which they derived), and validation of the pluripotency of the hiPSc lines is provided by Pluritest assessment of transcriptome datasets, prior to differentiation and downstream assays. Gene expression profiling in patient-derived dopamine neurons identifies candidate therapeutic molecules in Parkinson’s disease.
Project description:We have generated human induced Pluripotent Stem cells (hiPSc) using Retroviral virus-mediated delivery of reprogramming factors. hiPSc lines have been screened using SNP array to assess chromosomal stability (alongside the fibroblast lines from which they derived), and validation of the pluripotency of the hiPSc lines is provided by Pluritest assessment of transcriptome datasets, prior to differentiation and downstream assays. Gene expression profiling in patient-derived dopamine neurons identifies candidate therapeutic molecules in Parkinson’s disease.
Project description:The discovery of cell-free micro-RNAs in body fluids has made them a promising biomarker target in the field of neurodegenerative diseases. Although they have been reported to be differentially expressed in biofluids and tissue from sporadic Parkinson’s disease patients, it remains unclear whether similar observations can be made in patients with genetic forms of the disease. Since induced pluripotent stem cell derived neurons represent a widely used research model for both sporadic and familial Parkinson’s disease, we sought to assess the usability of this model for the identification of differentially expressed cell-free micro-RNAs in the context of the Parkinson’s disease related LRRK2 G2019S mutation in a proof-of-concept study. We isolated extracellular vesicles carrying cell-free RNA from patient-derived induced pluripotent stem cell lines carrying the LRRK2 G2019S mutation and their gene corrected isogenic controls. After generation of small-RNA libraries and differential expression analysis, we validated fourteen micro-RNAs in an independent batch of cell-free and cellular RNA via RT-qPCR. Finally, we selected eleven differentially expressed micro-RNAs from our cell culture experiments and quantified their expression levels in cerebrospinal fluid derived from two LRRK2 G2019S patients and two healthy controls.
Project description:Human induced pluripotent stem (iPS) cells have previously been derived from somatic cells using viral vectors that integrate transgenes into the genome. Genomic integration, however, can allow persistent leaky expression of the transgenes and can create insertional mutations, thus limiting the utility of these cells for both research and clinical applications. Here, we describe the derivation of human iPS cells free of vector and transgene sequences using non-integrating oriP/EBNA1-based episomal vectors. The resulting iPS cells are similar to human embryonic stem (ES) cells in both proliferative and developmental potential. These results demonstrate that reprogramming of human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one important obstacle to the clinical applications of these cells. This SuperSeries is composed of the following subset Series:; GSE15175: Human induced pluripotent stem cells free of exogenous DNA are derived with episomal vectors (fig 1.c); GSE15176: Human induced pluripotent stem cells free of exogenous DNA are derived with episomal vectors (fig 4.a) Experiment Overall Design: Total 21 samples were analyzed to confirm the similarity of human iPS cells derived with episomal vectors with human ES cells, and a dissimilarity with fibroblasts. Experiment Overall Design: Refer to individual Series
Project description:Clinical application of induced pluripotent stem (iPS) cells is limited by low efficiency of iPS derivation, and protocols that permanently modify the genome to effect cellular reprogramming. Moreover, safe and effective means of directing the fate of patient-specific iPS cells towards clinically useful cell types are lacking. Here we describe a simple, non-mutagenic strategy for reprogramming cell fate based on administration of synthetic mRNA modified to overcome innate anti-viral responses. We show that this approach can reprogram multiple human cell types to pluripotency with efficiencies that greatly surpass established protocols. We further show that the same technology can be used to efficiently direct the differentiation of RNA-induced pluripotent stem (RiPS) cells into terminally differentiated myogenic cells. Our method represents a safe, efficient strategy for somatic cell reprogramming and directing cell fates that has broad applicability for basic research, disease modeling and regenerative medicine. We isolated RNA from human RNA derived iPS cells, viral derived iPS cells, different human fibroblasts and human embryonic stem cells for hybridization to the Affymetrix gene expression microarrays.
Project description:Reprogramming somatic cells to induced pluripotent stem cells (iPSCs) sets their identity back to an embryonic age. This presents a fundamental hurdle for modeling late-onset disorders using iPSC-derived cells. We therefore developed a strategy to induce age-like features in multiple iPSC-derived lineages and tested its impact on modeling Parkinson’s disease (PD). We first describe markers that predict fibroblast donor age and observed the loss of these age-related markers following iPSC induction and re-differentiation into fibroblasts. Remarkably, age-related markers were readily induced in iPSC-derived fibroblasts or neurons following exposure to progerin including dopamine neuron-specific phenotypes such as neuromelanin accumulation. Induced aging in PD-iPSC-derived dopamine neurons revealed disease phenotypes requiring both aging and genetic susceptibility such as frank dendrite degeneration, progressive loss of tyrosine-hydroxylase expression and enlarged mitochondria or Lewy body-precursor inclusions. Our study presents a strategy for inducing age-related cellular properties and enables the modeling of late-onset disease features. Induced pluripotent stem cell-derived midbrain dopamine neurons from a young and old donor overexpressing either GFP or Progerin.
Project description:Transient expression of two factors, or from Oct4 alone, resulted in efficient generation of human iPSCs. The reprogramming strategy described revealed a potential transcriptional signature for human iPSCs yet retaining the gene expression of donor cells in human reprogrammed cells free of viral and transgene interference. Genetic reprogramming of somatic cells to a pluripotent state (induced pluripotent stem cells or iPSCs) by over-expression of specific genes has been accomplished using mouse and human cells. However, it is still unclear how similar human iPSCs are to human Embryonic Stem Cells (hESCs). Here, we describe the transcriptional profile of human iPSCs generated without viral vectors or genomic insertions, revealing that these cells are in general similar to hESCs but with significant differences. For the generation of human iPSCs without viral vectors or genomic insertions, pluripotent factors Oct4 and Nanog were cloned in episomal vectors and transfected into human fetal neural progenitor cells. The transient expression of these two factors, or from Oct4 alone, resulted in efficient generation of human iPSCs. The reprogramming strategy described here revealed a potential transcriptional signature for human iPSCs yet retaining the gene expression of donor cells in human reprogrammed cells free of viral and transgene interference. Moreover, the episomal reprogramming strategy represents a safe way to generate human iPSCs for clinical purposes and basic research. Experiment Overall Design: Gene expression profiles measured using human genome Affymetrix Gene Chip arrays were grouped by hierarchical clustering, and correlation coefficients were computed for all pair-wise comparisons
Project description:Transient expression of two factors, or from Oct4 alone, resulted in efficient generation of human iPSCs. The reprogramming strategy described revealed a potential transcriptional signature for human iPSCs yet retaining the gene expression of donor cells in human reprogrammed cells free of viral and transgene interference. Genetic reprogramming of somatic cells to a pluripotent state (induced pluripotent stem cells or iPSCs) by over-expression of specific genes has been accomplished using mouse and human cells. However, it is still unclear how similar human iPSCs are to human Embryonic Stem Cells (hESCs). Here, we describe the transcriptional profile of human iPSCs generated without viral vectors or genomic insertions, revealing that these cells are in general similar to hESCs but with significant differences. For the generation of human iPSCs without viral vectors or genomic insertions, pluripotent factors Oct4 and Nanog were cloned in episomal vectors and transfected into human fetal neural progenitor cells. The transient expression of these two factors, or from Oct4 alone, resulted in efficient generation of human iPSCs. The reprogramming strategy described here revealed a potential transcriptional signature for human iPSCs yet retaining the gene expression of donor cells in human reprogrammed cells free of viral and transgene interference. Moreover, the episomal reprogramming strategy represents a safe way to generate human iPSCs for clinical purposes and basic research.
Project description:Induced pluripotent stem cell (iPSC)-derived dopamine neurons provide an opportunity to model Parkinson’s disease (PD) but neuronal cultures are confounded by cellular heterogeneity. By applying high-resolution single cell transcriptomic analyses to Parkinson’s iPSC-derived dopamine neurons carrying the GBA-N370S risk variant, we exploited intra-culture cellular heterogeneity to identify a progressive axis of gene expression variation leading to endoplasmic reticulum stress. Analysis of genes differentially-expressed (DE) along this axis identified the transcriptional repressor histone deacetylase 4 (HDAC4) as an upstream regulator of disease progression. HDAC4 was mislocalized to the nucleus in PD iPSC-derived dopamine neurons and repressed genes early in the disease axis, leading to late deficits in protein homeostasis. Treatment of iPSC-derived dopamine neurons with compounds known to modulate HDAC4 activity upregulated genes early in the DE axis, and corrected Parkinson’s-related cellular phenotypes. Our study demonstrates how single cell transcriptomics can exploit cellular heterogeneity to reveal disease mechanisms and identify therapeutic targets.