Project description:Disease-specific induced pluripotent stem (iPS) cells have been used for a model to analyze pathogenesis of the disease. In this study, we generated iPS cells derived from a fibroblastic cell line of ataxia telangiectasia (AT-iPS cells), a neurodegenerative, inherited disease with chromosomal instability and hypersensitivity to ionizing radiation. AT-iPS cells exhibited hypersensitivity to X-ray irradiation, one of the characteristics of the disease. Surprisingly, while parental ataxia telangiectasia cells exhibited significant chromosomal abnormalities, AT-iPS cells did not show any chromosomal instability in vitro, i.e. maintenance of intact chromosomes at least by 80 passages (560 days) probably due to robust stability of pluripotent stem cells such as iPS cells and embryonic stem cells. The whole exome analysis also showed comparable nucleotide substitution speed in AT-iPS cells. Interestingly, after longer period of AT-iPS implantation into immunodeficient mice, teratoma generated by AT-iPS cells exhibited telangiectasia and carcinogenesis that are two characteristic symptoms of ataxia telangiectasia. Taken together, AT-iPS cells would be a good model for ataxia telangiectasia to clarify pathogenesis of the disease, and may allow us to facilitate development of drugs that inhibit ataxia and hypersensitivity to ionizing radiation for therapeutic application.
Project description:Disease-specific induced pluripotent stem (iPS) cells have been used for a model to analyze pathogenesis of the disease. In this study, we generated iPS cells derived from a fibroblastic cell line of ataxia telangiectasia (AT-iPS cells), a neurodegenerative, inherited disease with chromosomal instability and hypersensitivity to ionizing radiation. AT-iPS cells exhibited hypersensitivity to X-ray irradiation, one of the characteristics of the disease. Surprisingly, while parental ataxia telangiectasia cells exhibited significant chromosomal abnormalities, AT-iPS cells did not show any chromosomal instability in vitro, i.e. maintenance of intact chromosomes at least by 80 passages (560 days) probably due to robust stability of pluripotent stem cells such as iPS cells and embryonic stem cells. The whole exome analysis also showed comparable nucleotide substitution speed in AT-iPS cells. Interestingly, after longer period of AT-iPS implantation into immunodeficient mice, teratoma generated by AT-iPS cells exhibited telangiectasia and carcinogenesis that are two characteristic symptoms of ataxia telangiectasia. Taken together, AT-iPS cells would be a good model for ataxia telangiectasia to clarify pathogenesis of the disease, and may allow us to facilitate development of drugs that inhibit ataxia and hypersensitivity to ionizing radiation for therapeutic application. The parental AT1OS fibroblast cells and four independent AT-iPS clones were subjected to Illumina HumanCytoSNP-12 v2.1 BeadChip analysis.
Project description:ATM (ataxia telangiectasia mutated) kinase is crucial to a wide range of human developmental disorders and adult/pediatric malignancies. Its mutations are causally tied to ataxia telangiectasia, a multi-systemic congenital disorder mainly affecting brain and blood systems. We generated 4 separate ATM-knockout human pluripotent stem cell lines and differentiated them to form 3-dimensional brain cortical brain organoids. Brain cortical organoids are an excellent model of human developing cortex. Using these analyses, we identified ATM-dependent phosphorylation predominantly influences factors in neurogenesis, neuronal differentiation, cell morphogenesis, and microtubule cytoskeleton as well as kinases involved in ATM, BNDF, and WNT signaling, G2/M checkpoint, and p53 regulation. These findings have broad implications about diseases associated with ATM, including ataxia telangiectasia.
Project description:Disease-specific induced pluripotent stem (iPS) cells have been used for a model to analyze pathogenesis of the disease. We generated iPS cells derived from a fibroblastic cell line of ataxia telangiectasia (AT-iPS cells). In analysis of AT-iPS cells, the human wild-type iPS cell line (MRC5-iPS) was generated and cultured in the same conditions as the diseased iPS cell lines. It is an ideal control cell line for the disease and patient-specific iPS cell lines. Because MRC5-iPS cells exhibited considerable chromosomal abnormalities in vitro, we performed a structural alteration analysis by using a SNP genotyping array for MRC5-iPS cell line, Tic, at passage 15, passage 30, and passage 37.
Project description:The difficulty associated with generating induced pluripotent stem cells (iPSC) from patients with chromosomal instability syndromes suggests the cellular DNA damage response poses a barrier to reprogramming. Here we demonstrate that fibroblasts from patients with ataxia-telangiectasia (A-T) can be reprogrammed to bona-fide iPSC, albeit at a reduced efficiency. A-T iPSC display defective radiation-induced signaling, radiosensitivity and cell cycle checkpoint defects. Bioinformatic analysis of gene expression in the A-T iPSC identifies abnormalities in DNA damage signaling pathways as well as changes in mitochondrial and pentose phosphate pathways. A-T iPSC can be differentiated into functional neurons and thus represent a suitable model system to investigate A-T associated neurodegeneration. Collectively our data show that iPSC can be generated from a chromosomal instability syndrome and that these cells can be used to discover early developmental consequences of ATM deficiency, such as altered mitochondrial function, that may be relevant to A-T pathogenesis and amenable to therapeutic intervention. Three different cell types: fibroblasts, human embyronic stem cells, and induced pluripotent stem cells with heterozygote, homozygote A-T compared to normal samples.