Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA202866 | ENA |
REPOSITORIES: ENA
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Project description:Somatic cell nuclear transfer (SCNT) and induced pluripotent stem cells (iPSCs) represent two major approaches for somatic cell reprogramming. However, little attention has been paid to the ability of these two strategies in rejuvenating cells from donors with aging associated syndrome. Here, we utilized telomerase deficient (Terc-/-) mice to probe this question. SCNT-derived embryonic stem cells (ntESCs) and iPSCs were successfully derived from second generation (G2) and third generation (G3) of Terc-/- mice, and ntESCs showed better differentiation potential and self-renewal ability. Telomeres lengthened extensively in cloned embryos while remained or slightly increased in the process of iPSCs induction. Furthermore, G3 ntESCs exhibited improvement of telomere capping function as evidenced by decreased signal free ends and chromosome end-to-end fusion events. In contrast, there was a further decline of telomere capping function in G3 iPSCs. In addition to telomere dysfunction, mitochondria function was severely impaired in G3 iPSCs as evidenced by oxygen consumption rate (OCR) decline, reactive oxygen species (ROS) accumulation and dramatically increased mitochondria genome mutations while these deficiencies were greatly mitigated in G3 ntESCs. Our data proved the principle that SCNT-mediated reprogramming appears more superior than transcription factors induced reprogramming in terms of the resetting of telomere quality and mitochondria function, and thus, providing valuable information for further improvement of transcription factors mediated reprogramming. We compared the gene expression profile of G3 Terc-/- ntES and G3 Terc-/- iPS. Three biological repeats were included for each cell line.
2013-11-11 | E-GEOD-46860 | biostudies-arrayexpress
Project description:Background and Aims: Telomere dysfunction can increase tumor initiation by induction of chromosomal instability, but initiated tumor cells need to reactivate telomerase for genome stabilization and tumor progression. However, this concept has not been proven in vivo since appropriate mouse models were lacking. Here, we analyzed hepatocarcinogenesis (i) in a novel mouse model of inducible telomere dysfunction on a telomerase-proficient background, (ii) in telomerase knockout mice with chronic telomere dysfunction (G3 mTerc-/-), and (iii) in wild-type mice with functional telomeres and telomerase. Transient or chronic telomere dysfunction enhanced the rates of chromosomal aberrations during hepatocarcinogenesis, but only telomerase-proficient mice exhibited significantly increased rates of macroscopic tumor formation and cancer cell proliferation in response to telomere dysfunction. In contrast, telomere dysfunction resulted in pronounced accumulation of DNA damage, cell cycle arrest and apoptosis in telomerase-deficient liver tumors. Together, these data provide the first in vivo evidence that transient telomere dysfunction during early and late stages of tumorigenesis can promote chromosomal instability and carcinogenesis in telomerase-proficient mice in the absence of additional genetic checkpoint defects at germline level. RNA from liver tumors derived from from DEN treated TTD+ mice TTD- mice and RNA from normal liver 48h-72h after doxycycline induced transient telomere dysfunction in TTD+ and TTD- liver were isolated and RNA was extracted. Agilent Mouse 4x44K v2 arrays were used. DNA from liver tumors and corrresponding kidney as control derived from from DEN treated TTD+ mice, TTD- mice and mTERC-/- G3 mice was isolated and extracted using Phenol/Chloroform. Agilent Mouse 4x44K and Mouse 1x244K arrays were used.
2012-03-30 | E-GEOD-36813 | biostudies-arrayexpress
Project description:Background and Aims: Telomere dysfunction can increase tumor initiation by induction of chromosomal instability, but initiated tumor cells need to reactivate telomerase for genome stabilization and tumor progression. However, this concept has not been proven in vivo since appropriate mouse models were lacking. Here, we analyzed hepatocarcinogenesis (i) in a novel mouse model of inducible telomere dysfunction on a telomerase-proficient background, (ii) in telomerase knockout mice with chronic telomere dysfunction (G3 mTerc-/-), and (iii) in wild-type mice with functional telomeres and telomerase. Transient or chronic telomere dysfunction enhanced the rates of chromosomal aberrations during hepatocarcinogenesis, but only telomerase-proficient mice exhibited significantly increased rates of macroscopic tumor formation and cancer cell proliferation in response to telomere dysfunction. In contrast, telomere dysfunction resulted in pronounced accumulation of DNA damage, cell cycle arrest and apoptosis in telomerase-deficient liver tumors. Together, these data provide the first in vivo evidence that transient telomere dysfunction during early and late stages of tumorigenesis can promote chromosomal instability and carcinogenesis in telomerase-proficient mice in the absence of additional genetic checkpoint defects at germline level.
2012-03-31 | GSE36813 | GEO
Project description:Somatic cell nuclear transfer (SCNT) and induced pluripotent stem cells (iPSCs) represent two major approaches for somatic cell reprogramming. However, little attention has been paid to the ability of these two strategies in rejuvenating cells from donors with aging associated syndrome. Here, we utilized telomerase deficient (Terc-/-) mice to probe this question. SCNT-derived embryonic stem cells (ntESCs) and iPSCs were successfully derived from second generation (G2) and third generation (G3) of Terc-/- mice, and ntESCs showed better differentiation potential and self-renewal ability. Telomeres lengthened extensively in cloned embryos while remained or slightly increased in the process of iPSCs induction. Furthermore, G3 ntESCs exhibited improvement of telomere capping function as evidenced by decreased signal free ends and chromosome end-to-end fusion events. In contrast, there was a further decline of telomere capping function in G3 iPSCs. In addition to telomere dysfunction, mitochondria function was severely impaired in G3 iPSCs as evidenced by oxygen consumption rate (OCR) decline, reactive oxygen species (ROS) accumulation and dramatically increased mitochondria genome mutations while these deficiencies were greatly mitigated in G3 ntESCs. Our data proved the principle that SCNT-mediated reprogramming appears more superior than transcription factors induced reprogramming in terms of the resetting of telomere quality and mitochondria function, and thus, providing valuable information for further improvement of transcription factors mediated reprogramming.
2013-11-11 | GSE46860 | GEO
Project description:Critically short telomeres activate p53-mediated apoptosis, resulting in organ failure and causing malignant transformation. Mutations in genes responsible for telomere maintenance are linked to a number of specific human diseases. We derived induced pluripotent stem cells (iPSCs) from patients with mutations in the TERT and TERC telomerase genes. Telomerase-mutant iPSCs elongated telomeres, but at a lower rate than healthy iPSCs, and the magnitude of the elongation deficit correlated with the specific mutation’s impact on telomerase activity. However, elongation significantly varied among iPSC clones harboring the same mutation, and was affected by genetic and environmental factors. iPSCs cultured in hypoxia showed increased telomere length. Potential influence of residual expression of reprogramming factors on telomerase regulation and telomere length was ruled out by excising the transgenes after successful reprogramming. Evidence for telomerase-independent telomere elongation was not observed in these cells. We demonstrate that telomerase is required for telomere elongation in iPSCs and uncover heterogeneity in telomere maintenance even between clones derived from individual patients or siblings with the same mutation, indicating that telomere phenotype may be influenced by acquired and environmental agents. Our data underscore the necessity of studying multiple clones when using iPSCs to model disease. The exon array were done to validate the pluripotent phenotype of the derived normal and telomerase mutant iPSC and to potentially identify differentially expressed genes in mutant iPSC. Objective: confirming pluripotency by comparing telomerase mutated-, control-iPSC to human ESC and to their parental somatic cells (fibroblast used for iPSC derivation) 20 samples total, 5 different fibroblast cells, 13 iPSC lines, 1 ES line (H1) from different passages
2013-02-11 | E-GEOD-42869 | biostudies-arrayexpress
Project description:Critically short telomeres activate p53-mediated apoptosis, resulting in organ failure and causing malignant transformation. Mutations in genes responsible for telomere maintenance are linked to a number of specific human diseases. We derived induced pluripotent stem cells (iPSCs) from patients with mutations in the TERT and TERC telomerase genes. Telomerase-mutant iPSCs elongated telomeres, but at a lower rate than healthy iPSCs, and the magnitude of the elongation deficit correlated with the specific mutation’s impact on telomerase activity. However, elongation significantly varied among iPSC clones harboring the same mutation, and was affected by genetic and environmental factors. iPSCs cultured in hypoxia showed increased telomere length. Potential influence of residual expression of reprogramming factors on telomerase regulation and telomere length was ruled out by excising the transgenes after successful reprogramming. Evidence for telomerase-independent telomere elongation was not observed in these cells. We demonstrate that telomerase is required for telomere elongation in iPSCs and uncover heterogeneity in telomere maintenance even between clones derived from individual patients or siblings with the same mutation, indicating that telomere phenotype may be influenced by acquired and environmental agents. Our data underscore the necessity of studying multiple clones when using iPSCs to model disease. The exon array were done to validate the pluripotent phenotype of the derived normal and telomerase mutant iPSC and to potentially identify differentially expressed genes in mutant iPSC. Objective: confirming pluripotency by comparing telomerase mutated-, control-iPSC to human ESC and to their parental somatic cells (fibroblast used for iPSC derivation)
2013-02-11 | GSE42869 | GEO
Project description:Mammalian telomeres are formed by tandem repeats of the TTAGGG sequence, and shorten with each round of cell division in the absence of telomerase. Telomere shortening and dysfunction has been implicated in the pathology of several age-related diseases and premature ageing syndromes. Telomerase is important for telomere length maintenance. Telomerase RNA component, also known as TERC, is a component of telomerase. Terc knockout leads to telomerase deficiency and telomere shortening. Heterozygous telomerase-deficient (Terc+/-) mice were housed and bred for homozygous generation. ESC lines were generated with high efficiency from wild-type (WT, Terc+/+), heterozygous (Het, Terc+/-) and early- to late-generation (G1, G3 and G4) Terc-/- mouse blastocysts. Telomeres were shorter in Terc+/- ES cells than in WT ES cells, and further shortened from G1 to G4 Terc-/- ES cells. We took advantage of ES cell lines with various telomere lengths to investigate roles of telomere length on differentiation capacity of ES cells. We found that telomere length, but not telomerase activity, is required for differentiation of ES cells into epidermis. We performed microarray analysis to investigate differential gene expression profile at genome-wide levels between WT and G3/G4 Terc-/- (KO) mouse ES cells and during differentiation in vitro of WT and G4 Terc-/- mouse ES cells.
2016-01-29 | GSE77362 | GEO
Project description:TERC is the core subunit of telomerase which is responsible for adding telomeric sequences to the telomere ends. Besides being the RNA temple of telomerase, TERC is a typical Lnc RNA and ubiquitously expressed in normal somatic cells without telomerase activity. It is very likely that TERC has other, yet to be discovered functions in normal somatic cells independent of telomerase activity. Identifying the genomic occupancy of TERC helps to understand its functional mechanism on chromosomal DNA. Then, we analyzed the genome occupancy of TERC in MRC5 fibroblast cells that is without telomerase activity by ChIRP-seq, and found that there was not apparent enrichment of TERC on telomere sequences in normal somatic cells, but showed a significant enrichment on gene promoters/transcription start sites. This study provides a mechanistic insight of TERC on transcriptional regulation in normal somatic cells.
2022-03-28 | GSE183642 | GEO
Project description:Inflammatory bowel disease (IBD) is a challenging condition with limited therapeutic options. Inflammasome activation is integral to IBD pathogenesis, although the molecular instigators of its activation remain obscure. Here, we establish that telomere dysfunction activates the Yap1 transcriptional co-activator through pATM/c-Abl, which up-regulates expression of microbial receptors Nlrc4 and Nlrc5 and the cytokine pre-IL-18. Microbial engagement of these cytosolic receptors leads to production of mature IL-18, recruiting T cells and other immunocytes which secrete IFN-gamma to drive classical IBD pathology. Genotoxic stress per se (ionizing radiation) can also drive inflammasome activation. Alleviation of IBD pathology can be achieved via telomerase reactivation in intestinal epithelium, antibiotic treatment or pharmacological inhibition of Yap1 - reducing Nlrc4/5 expression as well as IL-18 and IFN-gamma production. Thus, telomere dysfunction-induced inflammasome activation identifies DNA damage signaling as a key instigator and promoter of IBD, illuminating potential novel therapeutic strategies for prevention and disease management.
2020-01-01 | GSE108902 | GEO