Cellular senescence is a program of irreversible cell cycle arrest that normal cells undergo in response to progressive shortening of telomeres, changes in telomeric structure, oncogene activation or oxidative stress. The underlying signalling pathways, potentially of major clinicopathological relevance, are unknown. A major stumbling block to studying senescence has been the absence of suitable model systems because of the asynchrony of this process in heterogeneous cell populations. To simplify this process many investigators study oncogene-induced senescence due to expression of activated oncogenes where senescence occurs prematurely without telomere attrition and can be induced acutely in a variety of cell types. We have taken a different approach by making use of the finding that reconstitution of telomerase activity by introduction of the catalytic subunit of human telomerase alone is incapable of immortalising all human somatic cells, but inactivation of the p16-pRB and p53-p21 pathways are required in addition. The ability of SV40 large T antigen to inactivate the p16-pRB and p53-p21 pathways has enabled us to use a thermolabile mutant of LT antigen, in conjunction with hTERT, to develop conditionally immortalised human (HMF3A) fibroblasts that are immortal but undergo an irreversible growth arrest when the thermolabile LT antigen is inactivated leading to activation of pRB and p53. When these cells cease dividing, senescence-associated- b-galactosidase activity is induced and the growth-arrested cells have morphological features and express genes in common with senescent cells. Since these cells growth arrest in a synchronous manner they are an excellent starting point for dissecting the pathways that underlie cellular senescence and act downstream of p16-pRB and p53-p21 pathways. We have combined genome-wide expression profiling with genetic complementation to undertake identification of genes that are differentially expressed when these conditionally immortalised human fibroblasts undergo senescence upon activation of the p16-pRB and p53-p21 tumour suppressor pathways.
Activation of nuclear factor-kappa B signalling promotes cellular senescence.
Cell line, Treatment
View SamplesWorms were treated with bcat-1 RNAi Jena Centre for Systems Biology of Ageing - JenAge (www.jenage.de) Overall design: 6 samples: 3 replicates for bcat-1 RNAi treatment; 3 replicates for controls
Branched-chain amino acid catabolism is a conserved regulator of physiological ageing.
Cell line, Subject
View SamplesJust as animal monozygotic twins can experience different environmental conditions by being reared apart, individual genetically-identical trees of the genus Populus can also be exposed to contrasting environmental conditions by being grown in different locations. As such, clonally-propagated Populus trees provide an opportunity to interrogate the impact of individual environmental history on current response to environmental stimuli. To test the hypothesis that current responses to an environmental stimulus, drought, are contingent on environmental history, the transcriptome-level drought responses of three economically important hybrid genotypes: DN34 (Populus deltoides x P. nigra); Walker (P. deltoides var. occidentalis x (P. laurifolia x P. nigra)); and, Okanese (Walker x (P. laurifolia x P. nigra)) derived from two different locations were compared. Strikingly, differences in transcript abundance patterns in response to drought were based on differences in geographic origin of clones for two of the three genotypes. This observation was most pronounced for the genotypes with the longest time since establishment and last common propagation. Differences in genome-wide DNA methylation paralleled the transcriptome level trends, where the clones with the most divergent transcriptomes and clone history had the most marked differences in the extent of total DNA methylation, suggesting an epigenetic basis for the clone-history-dependent transcriptome divergence. The data provide insights into the interplay between genotype and environment in the ecologically and economically important Populus genus, with implications for both the industrial application of Populus trees, and the evolution and persistence of these important tree species.
Clone history shapes Populus drought responses.
Specimen part, Treatment
View Samplesp63 mutations have been associated with several human hereditary disorders characterized by ectodermal dysplasia such as EEC syndrome, ADULT syndrome and AEC syndrome . The location and functional effects of the mutations that underlie these syndromes reveal a striking genotype-phenotype correlation. Unlike EEC and ADULT that result from missense mutations in the DNA-binding domain of p63, AEC is solely caused by missense mutations in the SAM domain of p63. We report a study on the TAp63a isoform, the first to be expressed during development of the embryonic epithelia, and on its naturally occurring Q540L mutant derived from an AEC patient. To assess the effects of the Q540L mutation, we generated stable cell lines expressing TAp63a wt, DeltaNp63 alpha or the TAp63 alpha-Q540L mutant protein and used them to systematically compare the cell growth regulatory activity of the mutant and wt p63 proteins and to generate, by microarray analysis, a comprehensive profile of differential gene expression. We found that the Q540L substitution impairs the transcriptional activity of TAp63a and causes misregulation of genes involved in the control of cell growth and epidermal differentiation.
The Hay Wells syndrome-derived TAp63alphaQ540L mutant has impaired transcriptional and cell growth regulatory activity.
No sample metadata fields
View SamplesPurpose: In this study, we identify global transcriptome alterations following removal of individual or multiple miR-196 family members in mouse. Next generation sequencing-derived transcriptome profiling (RNA-seq) was performed. Methods: A GFP reporter cassette was engineered to replace the mature miR-196a1 and miR-196a2 miRNA genomic loci in mouse (creating a knockout). GFP positive cells from an extensive knock-out allellic series of the three individual miR-196 genes, as detailed below, were isolated from E9.5 mouse embryos by FACS. miR-196b knockout cells were not marked with a fluorescent reporter and an assumption of co-expression with miR-196a2 was made. mRNA profiles were generated by deep sequencing in a minimum of four biological replicates per genotype, using an Illumina HiSeq 2000 instrument. Read information was mapped to the mouse genome and processed as described. Conclusions: Our study represents the first detailed analysis of embryonic transcriptomes following loss of single and multiple miR-196 family members. We identify complex dysregulation of many Hox genes, in addition to key developmental signalling pathways involved in somitogenesis. Overall design: mRNA profiles of E9.5 mouse embryos with miR-196 loss-of-function were generated by deep sequencing, in a minimum of four biological replicates, using Illumina HiSeq 2000.
Independent regulation of vertebral number and vertebral identity by microRNA-196 paralogs.
No sample metadata fields
View SamplesOchratoxin A gene expression profiling in liver and kidney, with time points of exposure from 7 days to 12 motnhs
A toxicogenomics approach to identify new plausible epigenetic mechanisms of ochratoxin a carcinogenicity in rat.
No sample metadata fields
View SamplesNaive pluripotent embryonic stem cells (ESCs) and embryonic germ cells (EGCs) are derived from the preimplantation epiblast and primordial germ cells (PGCs), respectively. We investigated whether differences exist between ESCs and EGCs, in view of their distinct developmental origins. PGCs are programmed to undergo global DNA demethylation; however, we find that EGCs and ESCs exhibit equivalent global DNA methylation levels. Importantly, inhibition of Erk and Gsk3b by 2i conditions leads to pronounced reduction in DNA methylation in both cell types. This is driven by Prdm14 and is associated with downregulation of Dnmt3a and Dnmt3b. However, genomic imprints are maintained in 2i, and we report derivation of EGCs with intact genomic imprints. Collectively, our findings establish that culture in 2i instills a naive pluripotent state with a distinctive epigenetic configuration that parallels molecular features observed in both the preimplantation epiblast and nascent PGCs.
Naive pluripotency is associated with global DNA hypomethylation.
Sex, Specimen part
View SamplesMasitinib is a tyrosine kinase inhibitor of c-Kit, PDGFR and , and to some extent Lyn of the Src kinase family. We evaluated the therapeutic potential of masitinib in vitro on human pancreatic tumour cell lines and in vivo in a mouse model of human pancreatic cancer.
Masitinib combined with standard gemcitabine chemotherapy: in vitro and in vivo studies in human pancreatic tumour cell lines and ectopic mouse model.
Specimen part, Cell line, Treatment
View SamplesPhotoreceptor disorders are collectively known as retinal degeneration (RD), and include retinitis pigmentosa (RP), cone-rod dystrophy and age related macular degeneration (AMD). These disorders are largely genetic in origin; individual mutations in any one of >200 genes cause RD, making mutation specific therapies prohibitively expensive. A better treatment plan, particularly for late stage disease, may involve stem cell transplants into the photoreceptor or ganglion cell layers of the retina. Stem cells from young mouse retinas can be transplanted, and can form photoreceptors in adult retinas. These cells can be grown in tissue culture, but can no longer form photoreceptors. We have used microarrays to investigate differences in gene expression between cultured retinal progenitor cells (RPCs) that have lost photoreceptor potential, postnatal day 1 (pn1) retinas and the postnatal day 5 (pn5) retinas that contain transplantable photoreceptors. We have also compared FACS sorted Rho-eGFP expressing rod photoreceptors from pn5 retinas with Rho-eGFP negative cells from the same retinas. We have identified over 300 genes upregulated in rod photoreceptor development in multiple comparisons, 37 of which have been previously identified as causative of retinal disease when mutated. It is anticipated that this research should bring us closer to growing photoreceptors in culture and therefore better treatments for RD. This dataset is also a resource for those seeking to identify novel retinopathy genes in RD patients.
Gene expression changes during retinal development and rod specification.
No sample metadata fields
View SamplesWe compared the transcriptom between respondrs and non-responders before and after PD-1 blockade therapy in melanoma patients, and defined their difference in context of T cell function. Overall design: We had 4 sapmles from 2 cohorts of patients collected before and after PD-1 ICI therapy according to their responses to PD-1 ICI therapy.
CX3CR1 identifies PD-1 therapy-responsive CD8+ T cells that withstand chemotherapy during cancer chemoimmunotherapy.
Subject
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