HuR controls apoptosis and activation response without effects on cytokine 3′ UTRs
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ABSTRACT:
PROVIDER: PRJNA501814 | ENA |
REPOSITORIES: ENA
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Project description:RNA binding proteins (RBPs) regulate gene expression through several post-transcriptional mechanisms. The broadly expressed HuR/ELAVL1 RBP is important for proper function of multiple cell types in the immune system, and has been proposed to positively control the expression of cytokine and other mRNAs upon activation by regulating their 3′ UTRs. However, this mechanism has not been previously dissected in stable cellular settings. In this study, HuR demonstrated strong anti-apoptotic and activation roles in the Jurkat T cell line. Detailed transcriptomic analysis of HuR knockout cells revealed a substantial negative impact on the activation program, coordinately preventing the expression of several gene categories related to the immune response, including all cytokines. Measurements of IL-2 production showed a significant defect in knockout cells, which was rescued upon reintroduction of HuR. Interestingly, the mechanism of HuR regulation did not involve control of the cytokine 3′ UTRs: HuR knockout did not affect the activity of several cytokine 3′ UTR reporters in 293 cells. Similarly, HuR had no effect on the regulation of IL-2 and TNF 3′ UTRs in resting or activated Jurkat cells. Instead, impaired cytokine production corresponded with defective induction of the IL-2 promoter upon activation. Accordingly, upregulation of the master transcription factor NFATC1 upon activation was also impaired in HuR KOs, without effects on its 3′ UTR. Together, these results indicate that HuR controls cytokine production through coordinated upstream pathways, and that additional mechanisms must be considered in investigating its function.
2019-06-05 | GSE121966 | GEO
Project description: Not available
| S-EPMC6546391 | biostudies-literature
Project description:Cell death is an important host defense in response to viral infections. In this study,we performed an unbiased whole-genome CRISPR/Cas9 screen in A549 lung adenocarcinoma cells to identify potential regulators involved in cell death triggered dsRNA, a common byproduct of viral replication. Of several top candidate genes, we identified the RNA binding protein ELAV like protein 1 (ELAVL1) (ELAVL1, also called HuR) that encodes Hu antigen R (HuR). Depletion of HuR by gene editing led to less cell death induced by dsRNA. We further demonstrated that HuR regulated apoptosis, and the RNA recognition motif (RRM) 3 of HuR was essential for its proapoptotic function. HuR bound mRNA of anti-apoptotic gene BCL2. HuR depletion had no influence on BCL2 mRNA levels, but instead downregulated the BCL2 translation. Polysome fractionation studies showed that HuR retarded the BCL2 mRNA in the non-translating pool of polysomes. Moreover, protection from dsRNA-induced apoptosis by HuR depletion required the presence of BCL2, indicating that the proapoptotic function of HuR is executed by suppressing BCL2. Consistently, HuR regulated apoptosis induced by infection of encephalomyocarditis or Semliki Forest virus, two unrelated positive strand RNA viruses. Collectively, our work identified a suite of proteins that regulate dsRNA-induced cell death, and elucidated the mechanism by which HuR acts as a pro-apoptotic factor.
2021-01-28 | GSE165625 | GEO
Project description:A Virus-acquired Host Cytokine Controls Systemic Aging by Antagonizing Apoptosis
| PRJNA436344 | ENA
Project description:The clinical management of liver cancer is challenged by the reduced availability of drugs targeting key signaling pathways and their modest benefits to patients. Senescence induction may represent a strategy for cancer treatment, especially as a combination therapy. The posttranslational modification (PTM) of proteins critically influences many biological processes, including gene expression, cell proliferation, differentiation and apoptosis, tumor progression, and drug resistance. Herein, we newly discovered that the RNA-binding protein (RBP) Human antigen R (HuR), a hub in liver cancer, is SUMOylated in the tumor sections of patients with hepatocellular carcinoma (HCC) in contrast to the surrounding tissue, as well as in human cell line and mouse models of the disease. SUMOylation of HuR promotes major cancer hallmarks, namely proliferation and invasion, whereas the absence of HuR SUMOylation results in a senescent phenotype with dysfunctional mitochondria and endoplasmic reticulum (ER). Mechanistically, SUMOylation induces a structural rearrangement of the RNA recognition motifs (RRMs) that modulates HuR binding affinity to its target mRNAs further modifying the transcriptomic profile towards hepatic tumor progression.
2024-02-19 | GSE197798 | GEO
Project description:HuR is a regulator of mRNA turnover or translation of inflammatory genes through binding to adenylate-uridylate-rich elements (ARE) and related motifs present in the 3’untranslated region (UTR) of mRNAs. We aimed to identify HuR targets in the human airway epithelial cell line BEAS-2B challenged with TNFa plus IFNg, a strong stimulus for inflammatory epithelial responses. Ribonucleoprotein (RNP) complexes from resting and cytokine-treated cells were immunoprecipitated (IP) using anti-HuR and isotype-control antibody, and eluted mRNAs were reverse-transcribed and hybridized to an inflammatory-focused gene array. The chemokines CCL2, CCL8, CXCL1 and CXCL2 ranked highest among 27 signaling and inflammatory genes significantly enriched in the HuR RNP-IP from stimulated cells over the control IP. Among these, 20 displayed published HuR binding motifs. Association of HuR with the four endogenous chemokine mRNAs was validated by single-gene RNP-IP, and shown to be 3’UTR-dependent by biotin pull-down assay. Cytokine treatment increased mRNA stability only for CCL2 and CCL8, and transient silencing and overexpression of HuR affected only CCL2 and CCL8 expression in primary and transformed epithelial cells. Cytokine-induced CCL2 mRNA was predominantly cytoplasmic; conversely, CXCL1 mRNA remained mostly nuclear and unaffected, as CXCL2, by changes in HuR levels. Increase in cytoplasmic HuR and HuR target expression partially relied on the inhibition of AMP-dependent kinase, a negative regulator of HuR nucleocytoplasmic shuttling. We postulate that HuR critically regulates the epithelial response, by associating with multiple adenylate-uridylate-rich elements (ARE)-bearing, functionally related inflammatory transcripts. On the basis of genome-wide studies probing the relationship between RNA-binding proteins and the functional profile of their associated transcripts, we combined the specific HuR immunoprecipitation of RNPs and the genome-scale microarray to profile the target mRNAs of HuR in the human airway epithelial cell line BEAS-2B challenged with very strong inflammatory stimulation, TNFa plus IFNG. The array platform we used is the Human Autoimmune and Inflammatory Response Gene Array (SuperArray Bioscience, Frederick, MD). To validate the association of HuR and its target mRNAs, we planned to apply biotin pull-down assay. HuR overexpression and knockdown assays were also planned to further verify the association of HuR and its target mRNAs. Overall, we did three biological replicates for the IP array experiments, which include both IgG1 control IP and HuR IP arrays.
2010-11-10 | E-GEOD-25264 | biostudies-arrayexpress
Project description:HuR is known to regulate mRNA stability and translatability in cytoplasm. In several human tumors, the level of HuR expression has been shown to correlate with poor disease outcome. In meningioma, however, the prognostic value and the potential pro-oncogenic properties of HuR remain obscure. To clarify these, transcriptome-wide analyses in IOMM-Lee cells were performed to pinpoint the detailed molecular consequences of HuR knockdown. In IOMM-Lee cells, transcriptomic analyses revealed that HuR knockdown deregulated the signaling pathway of HIF1A and upregulated the expression of genes for cytoplasmic mRNA processing body assembly, poly(A)-specific ribonuclease activity, positive regulation of apoptosis, negative regulation of RNA splicing, global genome nucleotide-excision repair, and positive regulation of cell cycle arrest. Interestingly, HuR knockdown under hypoxic culture condition potentiated further the effects of HuR knockdown on cell growth, apoptosis, and HIF1A expression.
2017-05-11 | GSE95212 | GEO
Project description:The 3’ UTR of messenger RNAs serves as the regulatory region that mediates post-transcriptional control by microRNAs and RNA-binding proteins (RBPs). Aside from individual sequence-specific binding and regulation, examples of interaction between these factors at particular 3’ UTR sites have emerged in recent studies. However, the whole picture of such higher-order regulatory modules across the transcriptome is lacking. Here, we investigate the interactions between HuR, a ubiquitous RBP, and Ago2, a core effector of the miRNA pathway, at the transcriptome-wide level. Using HITS-CLIP, we map HuR and miRNA binding sites on human 3’UTRs and assess their co-occurrence. Additionally, we demonstrate global effects of HuR knockdown on Ago2 occupancy, suggesting a co-regulatory relationship. Focusing on sites of Ago2-HuR overlap, 13 candidates were screened in luciferase reporter assays, compared to miRNA site mutant controls. Eleven of the sites showed a repressive activity, which displayed significant de-repression upon subsequent testing of the reporters in Dicer-null cells, substantiating miRNA dependence. To experimentally test for HuR’s role in co-regulation, we tested the reporters in CRISPR-generated HuR KO cells. Three of the miRNA sites demonstrated altered activities, indicating that HuR has an effect on miRNA repression at those sites. Our study presents an efficient search and validation system for studying miRNA-HuR interactions, which expands our understanding of the combinatorial post-transcriptional control of gene expression at the 3’ UTR.
2018-01-19 | GSE102320 | GEO
Project description:HuR is a regulator of mRNA turnover or translation of inflammatory genes through binding to adenylate-uridylate-rich elements (ARE) and related motifs present in the 3’untranslated region (UTR) of mRNAs. We aimed to identify HuR targets in the human airway epithelial cell line BEAS-2B challenged with TNFa plus IFNg, a strong stimulus for inflammatory epithelial responses. Ribonucleoprotein (RNP) complexes from resting and cytokine-treated cells were immunoprecipitated (IP) using anti-HuR and isotype-control antibody, and eluted mRNAs were reverse-transcribed and hybridized to an inflammatory-focused gene array. The chemokines CCL2, CCL8, CXCL1 and CXCL2 ranked highest among 27 signaling and inflammatory genes significantly enriched in the HuR RNP-IP from stimulated cells over the control IP. Among these, 20 displayed published HuR binding motifs. Association of HuR with the four endogenous chemokine mRNAs was validated by single-gene RNP-IP, and shown to be 3’UTR-dependent by biotin pull-down assay. Cytokine treatment increased mRNA stability only for CCL2 and CCL8, and transient silencing and overexpression of HuR affected only CCL2 and CCL8 expression in primary and transformed epithelial cells. Cytokine-induced CCL2 mRNA was predominantly cytoplasmic; conversely, CXCL1 mRNA remained mostly nuclear and unaffected, as CXCL2, by changes in HuR levels. Increase in cytoplasmic HuR and HuR target expression partially relied on the inhibition of AMP-dependent kinase, a negative regulator of HuR nucleocytoplasmic shuttling.
2010-11-10 | GSE25264 | GEO
Project description:Aging is characterized by degeneration of unique tissues. However, dissecting the interconnectedness of tissue aging remains a challenge. Here, we employ a muscle-specific DNA damage model in Drosophila to reveal secreted factors that influence systemic aging in distal tissues. Utilizing this model, we uncovered a cytokine, Diedel, that when secreted from muscle or adipose can attenuate age-related intestinal tissue degeneration by promoting proliferative homeostasis of stem cells. Diedel is both necessary and sufficient to limit tissue degeneration and extend lifespan. Secreted homologs of Diedel are also found in viruses, having been acquired from host genomes. Focusing on potential mechanistic overlap between cellular aging and viral-host cell interactions and, we found that Diedel is a functionally conserved inhibitor of apoptosis and can act as a systemic rheostat to modulate cell death during aging. These results highlight a key role for secreted antagonists of apoptosis in the systemic coordination of tissue aging.
2018-07-02 | GSE111248 | GEO