ABSTRACT: iPSCs from patients with NBS as a model uncovering disease mechanisms and a screening platform for anti-oxidants modifying genomic stability [iPSCs]
Project description:iPSCs from patients with NBS as a model uncovering disease mechanisms and a screening platform for anti-oxidants modifying genomic stability
Project description:iPSCs from patients with NBS as a model uncovering disease mechanisms and a screening platform for anti-oxidants modifying genomic stability [fibroblasts]
Project description:Nijmegen breakage syndrome (NBS) results from the absence of the NBS1 protein, responsible for detection of DNA double-strand breaks (DSBs). NBS is characterized by microcephaly, growth retardation, immunodeficiency, and cancer predisposition. Here we show successful reprogramming of NBS fibroblasts into induced pluripotent stem cells (NBS-iPSCs). Our data suggest a strong selection for karyotypically normal fibroblasts to go through the reprogramming process. NBS-iPSCs then acquire numerous chromosomal aberrations and show a delayed response to DSB induction. Furthermore, NBS-iPSCs display slower growth, mitotic inhibition, a reduced apoptotic response to stress and abnormal cell cycle-related gene expression. Importantly, NBS neural progenitor cells (NBS-NPCs) show down-regulation of neural developmental genes, which seems to be mediated by P53. Our results demonstrate the importance of NBS1 in early human development, shed new light on the molecular mechanisms underlying this severe syndrome and further expand our knowledge of the genomic stress cells experience during the reprogramming process. Gene expression analysis was performed on a total of 6 human cell lines, including WT and NBS Neural progenitor cells (NPCs) and NBS-iPSCs
Project description:Nijmegen breakage syndrome (NBS) results from the absence of the NBS1 protein, responsible for detection of DNA double-strand breaks (DSBs). NBS is characterized by microcephaly, growth retardation, immunodeficiency, and cancer predisposition. Here we show successful reprogramming of NBS fibroblasts into induced pluripotent stem cells (NBS-iPSCs). Our data suggest a strong selection for karyotypically normal fibroblasts to go through the reprogramming process. NBS-iPSCs then acquire numerous chromosomal aberrations and show a delayed response to DSB induction. Furthermore, NBS-iPSCs display slower growth, mitotic inhibition, a reduced apoptotic response to stress and abnormal cell cycle-related gene expression. Importantly, NBS neural progenitor cells (NBS-NPCs) show down-regulation of neural developmental genes, which seems to be mediated by P53. Our results demonstrate the importance of NBS1 in early human development, shed new light on the molecular mechanisms underlying this severe syndrome and further expand our knowledge of the genomic stress cells experience during the reprogramming process.
Project description:Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive genetic disorder, first described 1981 in Nijmegen, Holland. The characteristics of NBS include genomic instability (resulting in early onset of malignancies), premature aging, microcephaly and other growth retardations, immune deficiency, and impaired puberty and fertility in females. The consequence of these manifestations is a severe decrease in average life span, caused by cancer or infection of the respiratory and urinary tract. We reprogrammed fibroblasts from NBS patients into induced pluripotent stem cells (iPSCS) to bypass premature senescence and to generate an unlimited cell source for modeling purposes. We screened the influence of antioxidants on intracellular levels of ROS and DNA damage and found that EDHB was able to decrease DNA damage in the presence of high oxidative stress. Furthermore, we found that NBS fibroblasts, but not NBS-iPSCs were more susceptible to the induction of DNA damage than their normal counterparts. We performed global transcriptome analysis comparing NBS to normal fibroblasts and NBS-iPSCs to hESCs. There, we found, that TP53 was activated and cell cycle genes broadly down-regulated in NBS fibroblasts and up-regulation of glycolysis specifically in NBS-iPSCs.
Project description:Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive genetic disorder, first described 1981 in Nijmegen, Holland. The characteristics of NBS include genomic instability (resulting in early onset of malignancies), premature aging, microcephaly and other growth retardations, immune deficiency, and impaired puberty and fertility in females. The consequence of these manifestations is a severe decrease in average life span, caused by cancer or infection of the respiratory and urinary tract. We reprogrammed fibroblasts from NBS patients into induced pluripotent stem cells (iPSCS) to bypass premature senescence and to generate an unlimited cell source for modeling purposes. We screened the influence of antioxidants on intracellular levels of ROS and DNA damage and found that EDHB was able to decrease DNA damage in the presence of high oxidative stress. Furthermore, we found that NBS fibroblasts, but not NBS-iPSCs were more susceptible to the induction of DNA damage than their normal counterparts. We performed global transcriptome analysis comparing NBS to normal fibroblasts and NBS-iPSCs to hESCs. There, we found, that TP53 was activated and cell cycle genes broadly down-regulated in NBS fibroblasts and up-regulation of glycolysis specifically in NBS-iPSCs.
Project description:The human genome produces thousands of long non-coding RNAs (lncRNAs) – transcripts >200 nucleotides long that do not encode proteins. While critical roles in normal biology and disease have been revealed for a subset of lncRNAs, the function of the vast majority remains untested. Here, we developed a CRISPR interference (CRISPRi) platform targeting 16,401 lncRNA loci in 7 diverse cell lines including 6 transformed cell lines and human induced pluripotent stem cells (iPSCs). Large-scale screening identified 499 lncRNA loci required for robust cellular growth, of which 89% showed growth modifying function exclusively in one cell type. We further found that lncRNA knockdown can perturb complex transcriptional networks in a cell type-specific manner. These data underscore the functional importance and cell type-specificity of many lncRNAs.
Project description:Parkinson's disease (PD) is defined by the degeneration of nigral dopaminergic (DA) neurons and can be caused by monogenic mutations of genes such as parkin. The lack of phenotype in parkin knockout mice suggests that human nigral DA neurons have unique vulnerabilities. Here we generate induced pluripotent stem cells from normal subjects and PD patients with parkin mutations. We demonstrate that loss of parkin in human midbrain DA neurons greatly increases the transcription of monoamine oxidases and oxidative stress, significantly reduces DA uptake and increases spontaneous DA release. Lentiviral expression of parkin, but not its PD-linked mutant, rescues these phenotypes. The results suggest that parkin controls dopamine utilization in human midbrain DA neurons by enhancing the precision of DA neurotransmission and suppressing dopamine oxidation. Thus, the study provides novel targets and a physiologically relevant screening platform for disease-modifying therapies of PD. Genomic DNA was isolated from each of the four lines of iPSCs and labeled with Cy5. Pooled sex mismatched normal human genomic DNA was labeled with Cy3. Both samples are hybridized together on RPCI 21K BAC aCGH array.
Project description:Induced pluripotent stem cells (iPSCs) have become an essential tool for both modeling how causal genetic variants impact cellular function in disease, as well as being an emerging source of tissue for transplantation medicine. Unfortunately the preparation of somatic cells, their reprogramming and the subsequent verification of iPSC pluripotency are laborious, manual processes that limit the scale and level of reproducibility of this technology. Here we describe a modular, robotic platform for iPSC reprogramming that enables automated, high-throughput conversion of skin biopsies into iPSCs and differentiated cells with minimal manual intervention. Using this platform, we demonstrate that automated reprogramming and the pooled selection of pluripotent cells results in high quality, stable, iPSCs. These lines display less line-to-line variation than either manually produced lines or lines produced through automation followed by single colony-subcloning. The robotic platform we describe will enable the application of iPSCs to population-scale biomedical problems including the study of complex genetic diseases and the development of personalized medicines. Two independent human fibroblast lines were reprogrammed, using modified mRNA, into induced pluripotent stem cells (iPSCs). The genomic stability of several cell lines was evaluated using SNP arrays. Three iPSCs originating from one fibroblast line were tested at passages 8 and 20, with two of these derived as picked (clonal) lines and the third being a pooled population. Five iPSCs originating from a second fibroblast line were tested at passages 8 and 20, with three of these derives derived as picked (clonal) lines and two derived as pooled populations. The iPSCs were compared against the original parental fibroblasts.
Project description:Down syndrome (DS) is the most frequent cause of human congenital mental retardation. Cognitive deficits in DS result from perturbations of normal cellular processes both during development and in adult tissues, but the mechanisms underlying DS etiology remain poorly understood. To assess the ability of iPSCs to model DS phenotypes, as a prototypical complex human disease, we generated bona-fide DS and wild-type (WT) non-viral iPSCs by episomal reprogramming. DS iPSCs selectively overexpressed chromosome 21 genes, consistent with gene dosage, which was associated with deregulation of thousands of genes throughout the genome. DS and WT iPSCs were neurally converted at >95% efficiency, and had remarkably similar lineage potency, differentiation kinetics, proliferation and axon extension at early time points. However, at later time points DS cultures showed a two-fold bias towards glial lineages. Moreover, DS neural cultures were up to two times more sensitive to oxidative stress induced apoptosis, and this could be prevented by the anti-oxidant N-acetylcysteine. Our results reveal a striking complexity in the genetic alterations caused by trisomy-21 that are likely to underlie DS developmental phenotypes, and indicate a central role for defective early glial development in establishing developmental defects in DS brains. Furthermore, oxidative stress sensitivity is likely to contribute to the accelerated neurodegeneration seen in DS, and we provide proof of concept for screening corrective therapeutics using DS iPSCs and their derivatives. Non-viral DS iPSCs can therefore recapitulate features of complex human disease in vitro, and provide a renewable and ethically unencumbered discovery platform.