Homo sapiens
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PROVIDER: PRJNA115473 | ENA |
REPOSITORIES: ENA
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Project description:Molecular distinctions between the stasis and telomere attrition senescence barriers in cultured human mammary epithelial cells Normal human epithelial cells in culture have generally shown a limited proliferative potential of ~10-40 population doublings before encountering a stress-associated senescence barrier (stasis) associated with elevated levels of cyclin-dependent kinase inhibitors p16 and/or p21. We now show that simple changes in media composition can expand the proliferative potential of human mammary epithelial cells (HMEC) initiated as primary cultures to 50-60 population doublings, followed by p16(+), senescence-associated b-galactosidase(+) stasis. We compared the properties of growing and senescent pre-stasis HMEC with growing and senescent post-selection HMEC, i.e., cells grown in a serum-free medium that overcame stasis via silencing of p16 expression and that display senescence associated with telomere dysfunction. Cultured pre-stasis populations contained cells expressing markers associated with luminal and myoepithelial HMEC lineages in vivo, in contrast to the basal-like phenotype of the post-selection HMEC. Gene transcript and protein expression, DNA damage-associated markers, mean TRF length, and genomic stability, differed significantly between HMEC populations at the stasis vs. telomere attrition senescence barriers. Senescent isogenic fibroblasts showed greater similarity to HMEC at stasis than at telomere attrition, although their gene transcript profile was distinct from HMEC at both senescence barriers. These studies support our model of the senescence barriers encountered by cultured HMEC in which the first barrier, stasis, is Rb-mediated and independent of telomere length, while a second barrier (agonescence or crisis) results from telomere attrition leading to telomere dysfunction. Additionally, the ability to maintain long-term growth of genomically stable multi-lineage pre-stasis HMEC populations can greatly enhance experimentation with normal HMEC. 48 samples from Human Mammary Epithelial cells which includes samples from four different individuals at different passage levels which includes prestasis,intermediate,post selection and agonesence stages of cell cycle.
2010-05-28 | E-GEOD-16058 | biostudies-arrayexpress
Project description:Molecular distinctions between the stasis and telomere attrition senescence barriers in cultured human mammary epithelial cells Normal human epithelial cells in culture have generally shown a limited proliferative potential of ~10-40 population doublings before encountering a stress-associated senescence barrier (stasis) associated with elevated levels of cyclin-dependent kinase inhibitors p16 and/or p21. We now show that simple changes in media composition can expand the proliferative potential of human mammary epithelial cells (HMEC) initiated as primary cultures to 50-60 population doublings, followed by p16(+), senescence-associated b-galactosidase(+) stasis. We compared the properties of growing and senescent pre-stasis HMEC with growing and senescent post-selection HMEC, i.e., cells grown in a serum-free medium that overcame stasis via silencing of p16 expression and that display senescence associated with telomere dysfunction. Cultured pre-stasis populations contained cells expressing markers associated with luminal and myoepithelial HMEC lineages in vivo, in contrast to the basal-like phenotype of the post-selection HMEC. Gene transcript and protein expression, DNA damage-associated markers, mean TRF length, and genomic stability, differed significantly between HMEC populations at the stasis vs. telomere attrition senescence barriers. Senescent isogenic fibroblasts showed greater similarity to HMEC at stasis than at telomere attrition, although their gene transcript profile was distinct from HMEC at both senescence barriers. These studies support our model of the senescence barriers encountered by cultured HMEC in which the first barrier, stasis, is Rb-mediated and independent of telomere length, while a second barrier (agonescence or crisis) results from telomere attrition leading to telomere dysfunction. Additionally, the ability to maintain long-term growth of genomically stable multi-lineage pre-stasis HMEC populations can greatly enhance experimentation with normal HMEC.
2010-05-12 | GSE16058 | GEO
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.
2005-11-01 | E-SMDB-2210 | biostudies-arrayexpress
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.
2005-11-01 | E-SMDB-2046 | biostudies-arrayexpress
Project description:As a result of a chronic inflammation or in response to the constitutive activation of the beta-catenin pathway, the generation of reactive oxygen species causes telomere attrition and triggers intestinal cell commitment into a senescence program. Nonetheless, such events are known to promote their neoplastic transformation, suggesting that the escape from oxidative stress-induced senescence favors the emergence of deleterious cells. By setting up an in vitro model, we demonstrated that the escape of human colonic epithelial cells from chronic inflammation-induced senescence lied on the activation of a specific genetic program.
2018-06-30 | GSE70170 | GEO
Project description:Cellular senescence due to telomere dysfunction has been hypothesized to play a role in age-associated diseases including idiopathic pulmonary fibrosis (IPF). It has been postulated that paracrine mediators originating from senescent alveolar epithelia signal to surrounding mesenchymal cells and contribute to disease pathogenesis. However, murine models of telomere-induced alveolar epithelial senescence fail to display the canonical senescence-associated secretory phenotype (SASP) that is observed in senescent human cells. In an effort to understand human-specific responses to telomere dysfunction, we modelled telomere dysfunction-induced senescence in a human alveolar epithelial cell line. We hypothesized that this system would enable us to probe for differences in transcriptional and proteomic senescence pathways in vitro and to identify novel secreted protein (secretome) changes that potentially contribute to the pathogenesis of IPF. Following induction of telomere dysfunction, a robust senescence phenotype was observed. RNA-Seq analysis of the senescent cells revealed the SASP and comparisons to previous murine data highlighted species-specific responses to telomere dysfunction. We then conducted a proteomic analysis of the senescent cells using a novel biotin ligase capable of labeling secreted proteins. Candidate biomarkers selected from our transcriptional and secretome data were then evaluated in IPF and control patient plasma. Four novel proteins were found to be differentially expressed between the patient groups: stanniocalcin-1, contactin-1, tenascin C, and total inhibin. Our data show that human telomere-induced, alveolar epithelial senescence results in a transcriptional SASP that is distinct from that seen in analogous murine cells. Our findings suggest that studies in animal models should be carefully validated given the species-specific responses to telomere dysfunction. We also describe a pragmatic approach for the study of the consequences of telomere-induced alveolar epithelial cell senescence in humans.
2021-04-04 | PXD023381 | Pride
Project description:Telomere erosion contributes to age-associated tissue dysfunction and senescence, and p53 plays a crucial role in this response. We undertook a genome-wide screen to identify gene deletions that sensitized p53-positive human cells to loss of telomere integrity, and uncovered a previously unannotated gene, C16ORF72, which we term Telomere Attrition and p53 Response 1: TAPR1. CRISPR-Cas9 mediated deletion of TAPR1 led to elevated p53 and induction of p53 transcriptional targets. TAPR1-disrupted cells exhibited a synthetic-sick relationship with the loss of telomerase, or treatment with the topoisomerase II inhibitor doxorubicin. Stabilization of p53 with nutlin-3a further decreased cell fitness in cells lacking TAPR1 or telomerase, whereas deletion of TP53 rescued the decreased fitness of TAPR1-deleted cells. We propose that TAPR1 regulates p53 turnover, thereby tapering the p53-dependent response to telomere erosion. We discuss the possible implications of such a mechanism in the preservation of genome integrity during senescence or aging.
2021-03-04 | PXD022128 | Pride
Project description:- Gene expression changes linked to two step immortalization of human mammary epithelial cells (HMEC). - A lincRNA, MORT, associated with the mortal state, was identified - MORT is silenced by DNA methylation in immortal mammary epithelial cells Abstract: Immortality is an essential characteristic of human carcinoma cells. We recently developed an efficient, reproducible method that immortalizes human mammary epithelial cells (HMEC) in the absence of gross genomic changes by targeting two critical senescence barriers. Consistent transcriptomic changes associated with immortality were identified using microarray analysis of isogenic normal finite pre-stasis, abnormal finite post-stasis, and immortal HMECs from four individuals. 277 genes consistently changed in cells that transitioned from post-stasis to immortal. Gene ontology analysis of affected genes revealed biological processes significantly altered in the immortalization process. These immortalization-associated changes showed striking similarity to the gene expression changes seen in The Cancer Genome Atlas (TCGA) clinical breast cancer data. The most dramatic change in gene expression seen during the immortalization step was the down-regulation of an unnamed, incompletely annotated transcript that we called MORT, for mortality, since its expression was closely associated with the mortal, finite lifespan phenotype. We show here that MORT (ZNF667-AS1) is expressed in all normal finite lifespan human cells examined to date and is lost in immortalized HMEC. MORT gene silencing at the mortal/immortal boundary was due to DNA hypermethylation of its CpG island promoter. This epigenetic silencing is also seen in human breast cancer cell lines and in a majority of human breast tumor tissues. The functional importance of DNA hypermethylation in MORT gene silencing is supported by the ability of 5-aza-2’-deoxycytidine to reactivate MORT expression. Analysis of TCGA data revealed deregulation of MORT expression due to DNA hypermethylation in 15 out of the 17 most common human cancers. The epigenetic silencing of MORT in a large majority of the common human cancers suggests a potential fundamental role in cellular immortalization during human carcinogenesis.
2015-10-05 | GSE72353 | GEO
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
2006-03-06 | E-GEOD-4352 | biostudies-arrayexpress
Project description:The molecular mechanisms that drive hematopoietic stem cell (HSC) functional decline under conditions of stress are not completely understood. Here, in light of the recent advances in single-cell technologies, we sought to redefine the transcriptional and epigenetic landscape of mouse and human hematopoietic stem cells (HSCs) under telomeric stress, as that induced by pathogenic germline mutations in telomerase complex genes. These analyses revealed that telomere attrition maintains HSCs in a state of persistent metabolic activation and differentiation towards the megakaryocytic lineage through the cell-intrinsic upregulation of interferon (IFN) signaling response, which directly comprises HSCs’ self-renewal capabilities and eventually leads to their exhaustion. Telomerase reactivation completely restored HSC transcriptional homeostasis at the single-cell level, overcame enhanced megakaryocytic differentiation and significantly ameliorated HSCs’ repopulation capacity in the setting of competitive transplantation, suggesting that HSCs can repristinate their function upon telomere damage resolution. This study challenges the long-standing hypothesis that telomere attrition limits the proliferative potential of HSCs by inducing apoptosis or senescence and suggests that early intervention targeting the IFN axis could prevent bone marrow failure syndromes in patients with pathogenic mutations affecting telomere maintenance.
2021-10-23 | GSE169709 | GEO