Project description:We profiled the global gene expression of human primary fetal lung fibroblasts (HFL-1) at different stages while they were undergoing replicative senescence
Project description:Telomere shortening in populations of human mammary epithelial cells (HMECs) that survive early replicative arrest (M0) by the inactivation of p16INK4A during cell culture on plastic dishes leads to a state of permanent replicative arrest termed senescence. While culture of HMECs on feeder layers abrogates M0 and p16INK4A inactivation, progressive telomere attrition in these cells also eventually results in permanent replicative arrest. Expression of telomerase prevents both senescence on plastic (S-P) and senescence on feeder layers (S-FL) in HMECs, as it does also in cultured primary human fibroblasts. We report here that the gene expression profiles of senescence in HMECs of the same lineage maintained under different culture conditions showed surprisingly little commonality. Moreover, neither of these senescence-associated profiles in HMECs resembles the profile for senescence in human fibroblasts. These results indicate that senescence-associated alterations in gene expression resulting from telomere attrition are affected by culture conditions as well as by cell origins, and argue that replicative senescence at the molecular level is a diverse rather than unique cellular process.
Project description:By transcriptome analysis of IMR-90 human fibroblasts following oncogene-induced senescence (OIS) and replicative senescence (RS), we identified commonly regulated genes in both conditions.
Project description:Telomere shortening in populations of human mammary epithelial cells (HMECs) that survive early replicative arrest (M0) by the inactivation of p16INK4A during cell culture on plastic dishes leads to a state of permanent replicative arrest termed senescence. While culture of HMECs on feeder layers abrogates M0 and p16INK4A inactivation, progressive telomere attrition in these cells also eventually results in permanent replicative arrest. Expression of telomerase prevents both senescence on plastic (S-P) and senescence on feeder layers (S-FL) in HMECs, as it does also in cultured primary human fibroblasts. We report here that the gene expression profiles of senescence in HMECs of the same lineage maintained under different culture conditions showed surprisingly little commonality. Moreover, neither of these senescence-associated profiles in HMECs resembles the profile for senescence in human fibroblasts. These results indicate that senescence-associated alterations in gene expression resulting from telomere attrition are affected by culture conditions as well as by cell origins, and argue that replicative senescence at the molecular level is a diverse rather than unique cellular process.
Project description:We stably infected IMR90 fibroblasts with lentiviral vectors expressing doxycycline-inducible TRF2dBdM or vector control. Cells were treated with 1mg/ml of doxycycline for 7 days to induce senescence in the cells expressing TRF2dBdM before collecting RNA. IMR90 cells, either young (passage 10, population doubling ~20) or old (passage 24, population doubling ~40-48) were also used as a model of replicative senescence. The transcriptomes were analyzed using RNA microarrays.
Project description:This SuperSeries is composed of the following subset Series: GSE3730: Replicative senescence in human fibroblasts GSE3731: Replicative senescence in post-selection HMECs Abstract: Replicative senescence is the state of irreversible proliferative arrest that occurs as a concomitant of progressive telomere shortening. By using cDNA microarrays and the gabriel system of computer programs to apply domain-specific and procedural knowledge for data analysis, we investigated global changes in gene transcription occurring during replicative senescence in human fibroblasts and mammary epithelial cells (HMECs). Here we report the identification of transcriptional "fingerprints" unique to senescence, the finding that gene expression perturbations during senescence differ greatly in fibroblasts and HMECs, and the discovery that despite the disparate nature of the chromosomal loci affected by senescence in fibroblasts and HMECs, the up-regulated loci in both types of cells show physical clustering. This clustering, which contrasts with the random distribution of genes down-regulated during senescence or up-regulated during reversible proliferative arrest (i.e., quiescence), supports the view that replicative senescence is associated with alteration of chromatin structure. Refer to individual Series
Project description:Although senescence has long been implicated in aging-associated pathologies, it is not clearly understood how senescent cells are linked to these diseases. To address this knowledge gap, we profiled cellular senescence phenotypes and mRNA expression patterns during replicative senescence in human diploid fibroblasts. We identified a sequential order of gain-of-senescence phenotypes: low levels of reactive oxygen species, cell mass/size increases with delayed cell growth, high levels of reactive oxygen species with increases in senescence-associated M-NM-2-galactosidase activity (SA-M-NM-2-gal), and high levels of SA-M-NM-2-gal activity. Gene expression profiling revealed four distinct modules in which genes were prominently expressed at certain stages of senescence, allowing us to divide the process into four stages: early, middle, advanced, and very advanced. Interestingly, the gene expression modules governing each stage supported the development of the associated senescence phenotypes. Senescence-associated secretory phenotype-related genes also displayed a stage-specific expression pattern with three unique features during senescence: differential expression of interleukin isoforms, differential expression of interleukins and their receptors, and differential expression of matrix metalloproteinases and their inhibitory proteins. The analysis of time series gene expression level during replicaive senescence.
Project description:Cellular replicative senescence, a state of permanent cell-cycle arrest that occurs following an extended period of cell division in culture, has been linked to organismal aging, tissue repair and tumorigenesis. In this study, we comparatively investigated the global lipid profiles and mRNA content of proliferating and senescent-state BJ fibroblast cells. We found that both the expression levels of lipid-regulating genes, as well as the abundance of specific lipid families, are actively regulated. We further found that 19 polyunsaturated triacylglycerol species showed the most prominent changes during replicative senescence. We argue that diversion of polyunsaturated fatty acids to glycerolipid biosynthesis could be responsible for the accumulation of specific triacylglycerols. This, in turn, could be one of the cellular mechanisms to prevent lipotoxicity under increased oxidative stress conditions observed during replicative senescence. Collectively, our results place regulation of specific lipid species to a central role during replicative senescence.