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:RNA binding proteins regulate gene expression through several post-transcriptional mechanisms. The broadly expressed HuR/ELAVL1 is important for proper function of multiple immune cell types, and has been proposed to regulate cytokine and other mRNA 3' UTRs upon activation. However, this mechanism has not been previously dissected in stable cellular settings. In this study, HuR demonstrated strong anti-apoptotic and activation roles in Jurkat T cells. Detailed transcriptomic analysis of HuR knockout cells revealed a substantial negative impact on the activation program, coordinately preventing the expression of immune response gene categories, including all cytokines. Knockout cells showed a significant defect in IL-2 production, 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 3' UTR reporters in 293 cells, and had no effect on IL-2 and TNF 3' UTRs in resting or activated Jurkats. Instead, impaired cytokine production corresponded with defective induction of the IL-2 promoter upon activation. Accordingly, upregulation of NFATC1 was also impaired, without 3' UTR effects. Together, these results indicate that HuR controls cytokine production through coordinated upstream pathways, and that additional mechanisms must be considered in investigating its function.
| 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: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:Post-transcriptional regulatory networks are dependent on the interplay of many RNA-binding proteins having a major role in mRNA processing events in mammals. We have been interested in the concerted action of the two RNA-binding proteins hnRNP A1 and HuR, both stable components of immunoselected hnRNP complexes and having a major nuclear localization. Specifically, we present here the application of the RNA-immunoprecipitation (RIP)-Chip technology to identify a population of nuclear transcripts associated with hnRNP A1-RNPs as isolated from the nuclear extract of either HuR WT or HuR-depleted (KO) mouse embryonic fibroblast (MEF) cells. The outcome of this analysis was a list of target genes regulated via HuR for their association (either increased or reduced) with the nuclear hnRNP A1-RNP complexes. Real time PCR analysis was applied to validate a selected number of nuclear mRNA transcripts, as well as to identify pre-spliced transcripts (in addition to their mature mRNA counterpart) within the isolated nuclear hnRNP A1-RNPs. The differentially enriched mRNAs were found to belong to GO categories relevant to biological processes anticipated for hnRNP A1 and HuR (such as transport, transcription, translation, apoptosis and cell cycle) indicative of their concerted function in mRNA metabolism. Ribonucleoprotein Immunoprecipitation (RIP) using hnRNP A1 specific antibody was performed in nuclear extracts from HuR WT and HuR KO Mouse Embryonic Fibroblasts (MEFs). RNA isolated from these IPs together with nuclear RNA from the two cell types, was subjected to microarray analysis. Three biological replicates, representing three independent experiments, are available for each condition except in the case of nuclear RNA isolated from HuR WT MEFs that one replicate didn’t pass the quality control.
2013-11-01 | E-GEOD-49225 | biostudies-arrayexpress
Project description:Natural Killer (NK) cells are innate lymphocytes capable of controlling tumors and virus infections through direct lysis and cytokine production. NK cells also expand and accumulate in affected tissues, but the role of NK cell expansion in tumor and viral control is not well understood. Here, we describe that post-transcriptional regulation by the RNA-binding protein HuR is essential for NK cell expansion, without overtly affecting NK cell effector functions. HuR-dependent NK cell expansion facilitated control of solid tumors, but it was dispensable for control of tumor metastases. In virus infection, HuR-dependent NK cell expansion contributed to long-term viral control in the absence of adaptive immunity without affecting acute infection. HuR-deficient NK cells displayed defects in expression of and splicing in cell cycle-associated genes, including decreased expression and alternative splicing of Ska2, a component of the spindle and kinetochore complex that is involved in chromosome separation during cell division. Furthermore, we identified an essential role for SKA2 in NK cell expansion. These results show that post-transcriptional regulation by HuR specifically affects NK cell expansion which is required for control of several solid tumors and long-term virus infection.
2023-08-31 | GSE217392 | GEO
Project description:Although neurogenesis in the adult brain recapitulates processes that occur during embryonic development, adult neurogenesis exhibits distinct characteristics from its embryonic counterpart. However, the intrinsic mechanism underlying the differential regulation of neurogenesis between these two stages remains unclear. Herein, we show that the ablation of RNA-binding protein HuR in neural stem cells (NSCs) impairs adult, but not embryonic, neurogenesis. HuR is predominantly expressed in the cytoplasm of embryonic NSCs but translocates into the nucleus of adult NSCs. Transcriptomic analysis of HuR-deficient adult NSCs revealed that nuclear HuR primarily regulates alternative splicing of numerous premRNA transcripts, including focal adhesion kinase (FAK). HuR-deficient adult NSCs generate increased FAK mRNA isoforms with shorter 5’ UTRs, leading to enhanced FAK mRNA translation and hyperactivated FAK signaling, and inhibition of FAK ameliorates defective adult neurogenesis and impaired hippocampus-dependent learning in HuR-deficient mice. Taken together, these findings reveal novel mechanistic insights into the differential regulation of embryonic and adult neurogenesis through developmental cytoplasmic-to-nuclear translocation of HuR in NSCs.
2019-11-04 | GSE137323 | GEO