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:Differentiation of induced pluripotent stem cells (iPSCs) into specialized cell types is essential for uncovering cell-type specific molecular mechanisms and interrogating cellular function. Transcription factor (TF) screens have enabled efficient production of a few cell types; however, engineering cell types that require complex TF combinations remains challenging. Here, we report an iterative, high-throughput single-cell TF screening method that enables identification of TF combinations for specialized cell differentiation, which we validated by differentiating human microglia-like cells. We found that the expression of six TFs, SPI1, CEBPA, FLI1, MEF2C, CEBPB, and IRF8, is sufficient to differentiate human iPSC into cells with transcriptional and functional similarity to primary human microglia within 4 days.
Project description:Differentiation of induced pluripotent stem cells (iPSCs) into specialized cell types is essential for uncovering cell-type specific molecular mechanisms and interrogating cellular function. Transcription factor (TF) screens have enabled efficient production of a few cell types; however, engineering cell types that require complex TF combinations remains challenging. Here, we report an iterative, high-throughput single-cell TF screening method that enables identification of TF combinations for specialized cell differentiation, which we validated by differentiating human microglia-like cells. We found that the expression of six TFs, SPI1, CEBPA, FLI1, MEF2C, CEBPB, and IRF8, is sufficient to differentiate human iPSC into cells with transcriptional and functional similarity to primary human microglia within 4 days.
Project description:Differentiation of induced pluripotent stem cells (iPSCs) into specialized cell types is essential for uncovering cell-type specific molecular mechanisms and interrogating cellular function. Transcription factor (TF) screens have enabled efficient production of a few cell types; however, engineering cell types that require complex TF combinations remains challenging. Here, we report an iterative, high-throughput single-cell TF screening method that enables identification of TF combinations for specialized cell differentiation, which we validated by differentiating human microglia-like cells. We found that the expression of six TFs, SPI1, CEBPA, FLI1, MEF2C, CEBPB, and IRF8, is sufficient to differentiate human iPSC into cells with transcriptional and functional similarity to primary human microglia within 4 days.
