This SuperSeries is composed of the SubSeries listed below.
Independence of repressive histone marks and chromatin compaction during senescent heterochromatic layer formation.
Sex, Cell line, Treatment
View SamplesThe expansion of repressive epigenetic marks has been implicated in heterochromatin formation during embryonic development, but the general applicability of this mechanism is unclear. Here we show that nuclear rearrangement of repressive histone marks H3K9me3 and H3K27me3 into non-overlapping structural layers characterizes senescence-associated heterochromatic foci (SAHF) formation in human fibroblasts. However, the global landscape of these repressive marks remains unchanged upon SAHF formation, suggesting that in somatic cells heterochromatin can be formed through the spatial repositioning of pre-existing repressively marked histones. This model is reinforced by the correlation of pre-senescent replication timing with both the subsequent layered structure of SAHFs and the global landscape of the repressive marks, allowing us to integrate microscopic and genomic information. Furthermore, modulation of SAHF structure does not affect the occupancy of these repressive marks nor vice versa. These experiments reveal that high-order heterochromatin formation and epigenetic remodeling of the genome can be discrete events.
Independence of repressive histone marks and chromatin compaction during senescent heterochromatic layer formation.
Sex, Cell line, Treatment
View SamplesMetabolism is tightly coupled with the process of aging, and tumorigenesis. However, the mechanisms regulating metabolic properties in different contexts remain unclear. Cellular senescence is widely recognized as an important tumor suppressor function and accompanies metabolic remodeling characterized by increased mitochondrial oxidative phosphorylation (OXPHOS). Here we showed retinoblastoma (RB) is required for the increased OXPHOS in oncogene-induced senescent (OIS) cells. Combined metabolic and gene expression profiling revealed that RB mediated activation of the glycolytic pathway in OIS cells, causing upregulation of several glycolytic genes and concomitant increases in the levels of associated metabolites in the glycolytic pathway. Knockdown of these genes by small interfering RNAs (siRNAs) resulted in decreased mitochondrial respiration, suggesting that RB-mediated glycolytic gene activation promotes metabolic flux into the OXPHOS pathway. These results suggest that coordinate transcriptional activation of metabolic genes by RB enables OIS cells to maintain metabolically bivalent states that both glycolysis and OXPHOS are highly active. Collectively, our findings demonstrated a previously unrecognized function of RB in OIS cells.
Retinoblastoma protein promotes oxidative phosphorylation through upregulation of glycolytic genes in oncogene-induced senescent cells.
Cell line, Treatment
View SamplesTo identify transcripts altered upon LIN-41 knockdown, we transfected either a control siRNA or one of two different LIN-41 siRNAs into human embryonic stem cells and collected total RNA 72 hours after transfection. Overall design: We compared transcript levels between control siRNA or LIN-41 siRNA treated cells.
The let-7/LIN-41 pathway regulates reprogramming to human induced pluripotent stem cells by controlling expression of prodifferentiation genes.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Dissecting the unique role of the retinoblastoma tumor suppressor during cellular senescence.
Cell line
View SamplesThe action of RB as a tumor suppressor has been difficult to define, in part, due to the redundancy of the related proteins p107 and p130. By coupling advanced RNAi technology to suppress RB, p107 or p130 with a genome wide analysis of gene expression in growing, quiescent or ras-senescent cells, we identified a unique and specific activity of RB in repressing DNA replication as cells exit the cell cycle into senescence, a tumor suppressive program.
Dissecting the unique role of the retinoblastoma tumor suppressor during cellular senescence.
Cell line
View SamplesThis study explored the role of the growth hormone (GH) / insulin-like growth factor 1 (IGF-1) axis on the life-long caloric restriction (CR)-associated remodeling of white adipose tissue (WAT). Adipocyte size and gene expression profiles, using high-density oligonucleotide microarrays, were analyzed in WAT of six- to seven-month old wild Wistar rats fed ad libitum (AL) or subjected to a 30% caloric restriction (CR), and heterozygous transgenic dwarf rats bearing an anti-sense GH transgene fed ad libitum (Tg). While not significant in Tg rats, adipocyte size was significantly reduced in CR rats compared with AL rats. The microarray data based on the principal component analysis demonstrated that the gene expression profile of CR rats markedly differed from the AL rats, while Tg hardly differed, suggesting that CR-associated WAT remodeling was predominantly regulated in a GH/IGF-1-independent manner. The gene cluster with the largest change induced by CR included several genes involved in lipid biosynthesis and inflammation. Moreover, many of the genes transcriptionally regulated by sterol regulatory element binding proteins (SREBPs) were found in the cluster related to lipid biosynthesis. Real-time reverse transcription polymerase chain reaction analysis confirmed that the expression of SREBP-1 and its down-stream targets was particularly up-regulated in CR rats compared with SREBP-2 and its down-stream targets. Our findings suggest that SREBP-1 is a major transcription factor in CR-associated remodeling of WAT, and might be one of the key regulators of the anti-aging and pro-longevity effects of CR.
Caloric restriction-associated remodeling of rat white adipose tissue: effects on the growth hormone/insulin-like growth factor-1 axis, sterol regulatory element binding protein-1, and macrophage infiltration.
Age, Specimen part
View SamplesIn this study, we have uncovered novel proteolytic processing of the histone H3 tail in senescence models in primary fibroblasts and melanocytes. Cleavage of H3 tail occurs at two distinct residues and is mediated by Cathepsin L. We show that variant H3.3 is preferentially cleaved, and that cleaved histones are associated with chromatin and incorporated into nucleosomes. We also found that the histone chaperone ASF1a is required for chromatin incorporation of the cleaved histone species. Further, we show that overexpression of cleaved H3.3 induces a senescence program in fibroblasts in the absensence of oncogenic signaling. Overall design: For the RNA-seq studies, growing IMR90 fibroblasts were compared to cells induced to senesce via oncogene activation or cleaved H3.3 overexpression. Growing controls consist of IMR90 cells infected with empty retroviral construct pBabe and grown under normal conditions for 13 days prior to RNA isolation. For oncogene-induced senescence samples, IMR90s carrying a tamoxifen-inducible H-RasV12 retroviral construct were induced to senesce by addition of 10nM tamoxifen to the media for 8 days. Finally, IMR90s were infected with a retroviral construct expressing the cleaved form of H3.3 with a C-terminal Flag tag. RNA samples form this group were isolated at days 3 (early) and 13 (late) post-infection. In all cases, total RNA samples were isolated using RNeasy kit (Qiagen) and prepared at the Icahn School of Medicine at Mount Sinai Genomics Core Facility for poly A library construction and sequencing on IlluminaHiSeq 2500.
Histone H3.3 and its proteolytically processed form drive a cellular senescence programme.
No sample metadata fields
View SamplesDifferential gene expression was analyzed for FACS sorted Math1::Cre; ROSA-tdTomato from hand dissected cochlear nuclei of wild type and Hoxa2/Hoxb2 mutant mice Overall design: In order to investigate the role of Hoxa2 and Hoxb2 transcription factors in a subset of cells of the cochlear nucleus, we generated double conditional knock-out by crossing the deleter line Math1::Cre crossed with Rosa tdTomato; Hoxa2fl/fl; Hoxb2fl/fl and Rosa tdTomato wild type background. FACS sorted cells from hand dissected cochlear nuclei were than processed and RNA-seq performed (see extract protocol and library construction protocol).
Hox2 Genes Are Required for Tonotopic Map Precision and Sound Discrimination in the Mouse Auditory Brainstem.
No sample metadata fields
View SamplesPrenatal exposure to valproic acid, an established anti-epileptic drug, has been reported to impair postnatal cognitive function of children from epileptic mothers. Nevertheless, its pathology and proper treatment to minimize the effects remain unknown. In mice, we found that the postnatal cognitive function impairment was mainly caused by a reduction of adult neurogenesis and abnormal neuronal features in the hippocampus, which could be ameliorated by voluntary running.
Reduced Adult Hippocampal Neurogenesis and Cognitive Impairments following Prenatal Treatment of the Antiepileptic Drug Valproic Acid.
Sex, Specimen part, Treatment
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