Project description:Human transcriptome analysis of U2OS cells treated with nocodazole or DMSO (Control). The gene expression profiling will reveal senescence-associated genes induced upon nocodazole treatment. Our preliminary data show that antimitotic drugs treatment promote post-slippage senescence.
Project description:The aging of pancreatic beta-cells may undermine their ability to compensate for insulin resistance, leading to the development of type 2 diabetes (T2D). Aging beta-cells acquire markers of cellular senescence and develop a senescence-associated secretory phenotype (SASP) that can lead to senescence and dysfunction of neighboring cells through paracrine actions, contributing to beta-cell failure. Herein, we defined the beta-cell SASP signature based on unbiased proteomic analysis of conditioned media of cells obtained from human senescent beta-cells. These experiments revealed that the beta-cell SASP is enriched for factors associated with inflammation, cellular stress response, and extracellular matrix remodeling across species.
Project description:The METTL3-METTL14 complex, as the "writer" of N6-methyladenosine (m6A), plays an important role in many biological processes. Previous studies have shown that overexpression of Mettl3 can increase the level of m6A and promotes somatic cell reprogramming. Here, we demonstrate that Mettl14, another component of the methyltransferase (MTase) complex, can significantly enhance the generation of induced pluripotent stem cells (iPSCs) in m6A independent manner. Cooperating with Oct4, Sox2, Klf4 and c-Myc (OSKM), Mettl14 transiently increased the senescence-associated secretory phenotype (SASP) gene expression in the non-reprogramming cells at the late reprogramming stage. The conditional medium in reprogramming intermediates overexpressing Mettl4 or its mutant could enhanced the reprogramming, so do IL-6, a component of SASP. Corespondingly, blocking of SASP using senolytic agent or NF-κB inhibitor impairs the effect of Mettl14 on reprogramming. . Our work highlights the m6A independent function of Mettl14 and provides new insight into the interplay between senescence and reprogramming in vitro.
Project description:We report single nucleus RNAseq data from the mouse intestinal organoids cultured in quiescent or senescent conditioned media. Analysis revealed changes in cell composition and gene expression caused by SASP factors in senescent conditioned media.
Project description:Cellular senescence is a therapy endpoint in melanoma, and the senescence-associated secretory phenotype (SASP) can affect tumor growth and microenvironment, influencing treatment outcomes. Metabolic interventions can modulate the SASP, and an enhanced mitochondrial energy metabolism supports resistance to therapy in melanoma. In a previous report we showed that in melanoma, senescence induced by the DNA methylating agent temozolomide, increases fusion proteins mitofusins 1 and 2. Silencing Mfn1 or Mfn2 expression reduced interleukin-6 secretion by senescent cells. Here we expanded these observations evaluating the secretome of senescent melanoma cells using shotgun proteomics, and explored the impact of silencing Mfn1 on the SASP. A significant increase in proteins reported to reduce the immune response towards the tumor was found in the media of senescent cells. The secretion of several of these immunomodulatory proteins was affected by Mfn1 silencing, among them was galectin-9. In agreement, tumors lacking mitofusin 1 responded better to treatment with the methylating agent dacarbazine, tumor size was reduced and a higher immune cell infiltration was detected in the tumor. Our results highlight mitochondrial dynamic proteins as potential pharmacological targets to modulate the SASP in the context of melanoma treatment.
Project description:Senescent cells drive age-related tissue dysfunction partially via the induction of a chronic senescence-associated secretory phenotype (SASP). Mitochondria are major regulators of the SASP; however, the underlying mechanisms have not been elucidated. Mitochondria also control apoptosis, a cell fate generally perceived as distinct from cellular senescence, which is apoptosis resistant. Here, we show that mitochondrial outer membrane permeability (MOMP) occurring in a small subset of mitochondria is a feature of cellular senescence. This process, called minority MOMP (miMOMP), depends on the formation of BAX and BAK macropores and results in release of mitochondrial DNA (mtDNA) into the cytosol, which in turn activates the cGAS/STING pathway, a major regulator of the SASP. Importantly, we found that inhibition of MOMP in vivo decreases inflammatory markers and improves healthspan parameters in aged mice. Our results propose the novel concept that apoptosis and senescence are regulated by similar mitochondrial-dependent mechanisms, and that sub-lethal mitochondrial apoptotic stress is a major driver of the SASP. We also provide proof-of-concept that inhibition of miMOMP may be a new therapeutic avenue to improve healthspan.
Project description:Cellular senescence is a stable cell growth arrest that is characterized by silencing of proliferation-promoting genes through compaction of individual chromosomes into senescence-associated heterochromatin foci (SAHF). Paradoxically, senescence is also accompanied by increased expression of certain secreted factors such as cytokines and chemokines, known as senescence-associated secretory phenotype (SASP). How SASP genes are excluded from SAHF-mediated global gene silencing remains unclear. Here we report that HMGB2 orchestrates the chromatin landscape of SASP gene loci. HMGB2 preferentially localizes to SASP gene loci during senescence. Loss of HMGB2 during senescence blunts SASP gene expression by allowing for spreading of repressive heterochromatin into SASP gene loci. This correlated with incorporation of SASP gene loci into SAHF. Our results establish HMGB2 as a novel master regulator that orchestrates SASP through preventing heterochromatin spreading to allow for exclusion of SASP gene loci from a global heterochromatin environment during senescence.
Project description:Rapid advancements in next generation sequencing (NGS) have revolutionized system-based analysis of genome-wide expression, cellular pathways and stress responses. We performed this cGAS-STING-associated study to streamline the transcriptomic profiling (RNA-seq) of human stromal cells manifesting a typical senescence-associated secretory phenotype (SASP) in a DNA damage setting.
Project description:This SuperSeries is composed of the SubSeries listed below. Oncogene-induced senescence (OIS) and therapy-induced senescence (TIS), while tumor-suppressive, also promote procarcinogenic effects by activating the DNA damage response (DDR), which in turn induces inflammation. This inflammatory response prominently includes an array of cytokines known as the senescence-associated secretory phenotype (SASP). Previous observations link the transcription-associated methyltransferase and oncoprotein MLL1 to the DDR, leading us to investigate the role of MLL1 in SASP expression. Our findings reveal direct MLL1 epigenetic control over proproliferative cell cycle genes: MLL1 inhibition represses expression of proproliferative cell cycle regulators required for DNA replication and DDR activation, thus disabling SASP expression. Strikingly, however, these effects of MLL1 inhibition on SASP gene expression do not impair OIS and, furthermore, abolish the ability of the SASP to enhance cancer cell proliferation. More broadly, MLL1 inhibition also reduces âSASP-likeâ inflammatory gene expression from cancer cells in vitro and in vivo independently of senescence. Taken together, these data demonstrate that MLL1 inhibition may be a powerful and effective strategy for inducing cancerous growth arrest through the direct epigenetic regulation of proliferation-promoting genes and the avoidance of deleterious OIS- or TIS-related tumor secretomes, which can promote both drug resistance and tumor progression. Previously published samples GSM1135046, GSM1135044, GSM1135047, and GSM1135045 were also studied in this investigation and appear in GSE36641. This did not involve re-sequencing or re-alignment, nor any other deviation from the data protocols in that series. Refer to individual Series