Biochemical Profiling and Structural Basis of ADAR1-Mediated RNA Editing
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE285023 | GEO | 2025/03/31
REPOSITORIES: GEO
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Project description:ADAR1 catalyzes Adenosine-to-Inosine (A-to-I) editing of double-stranded RNA and regulates global expression output through its interactions with RNA and other proteins. ADARs play important roles in development and disease, and previous work has shown that ADAR1 is oncogenic in a growing list of cancer types. Here we show that ADAR1 is important for growth and invasion in triple negative breast cancer cells, as ADAR1 loss yields reduced growth, migration & invasion, and mammosphere formation. Global RNA-seq analyses demonstrate that ADAR1 regulates both coding and non-coding targets via expression level and/or A-to-I editing. We demonstrated that a recoding edit in FLNB (chr3:58156064) inhibits the tumor suppressive activities of the protein to promote growth & invasion. We show that several tumor suppressor microRNAs are also downregulated by ADAR1 to promote cell cycle progression and invasion. This work describes several novel mechanisms of ADAR1-mediated oncogenesis in triple negative breast cancer, providing support to strategies for targeting ADAR1 in this aggressive cancer type with few treatment options.
2022-03-14 | GSE177056 | GEO
Project description:Aberrant RNA-editing was observed in several human tumors, but its significance is mostly unknown. Here we show that ADAR1, a ubiquitous RNA-editing enzyme, is commonly lost in metastatic melanoma cells and specimens. Experimental ADAR1 silencing significantly alters melanoma cell morphology, facilitates proliferation and cell-cycle, and increases the tumorigenicity in-vivo. A series of ADAR1 truncation mutants establishes a novel RNA-editing-independent role for ADAR1 in controlling the nuclear and cytoplasmic processing steps of miRNA biogenesis. Altered expression of ADAR1-controled miRNAs accounts for the observed phenotype. We show that the oncogenic miR-17-5p endogenously regulates ADAR1 expression and that its genomic sequence is frequently amplified in melanoma to overexpress the mature miR-17-5p form. ADAR1 and miR-17-5p are ubiquitously expressed, suggesting the generality of this mechanism. Melanoma cell line expressing low ADAR1 levels (ADAR1-Knockdown) using shRNA technique were selected for RNA extraction and hybridization on Affymetrix microarrays. We sought to examine the alterations in the genes and microRNA expression profile in the manipulated cell system, due to ADAR1 possible involvement cancer development. To that end, we selected ADAR1-knockdown (ADAR1-KD) cells that demonstrated an enhanced aggressive phenotype both in vivo and in vitro as compared to the control cells (Control).
2012-08-31 | E-GEOD-31963 | biostudies-arrayexpress
Project description:ADAR1 regulates the accumulation of endeognouse double-stranded RNA (dsRNA), a pro-inflammatory/innate immune activator. The purpose of this study was to measure the effects of ADAR1 suppression in human astrocytes and determine RNAs regulated by ADAR1. Primary human astrocytes were culture and transfected with a scramble or ADAR1 siRNA. RNA was isolated from these cells for total RNA-seq to analyze changes in gene/repetitive element expression and RNA editing.
2023-09-07 | GSE225369 | GEO
Project description:The ADAR RNA editing enzymes deaminate adenosine bases to inosines in cellular RNAs, recoding open reading frames. Human ADAR1 mutations cause Aicardi-Goutieres Syndrome (AGS) and Adar1 mutant mice showing an aberrant interferon response and death by embryonic day E12.5 model the human disease. Searches have not identified key ADAR1 RNA editing sites recoding immune/haematopoietic proteins but editing is widespread in Alu sequences. We show that Adar1 embryonic lethality is rescued in Adar1; Mavs double mutant mice in which general antiviral responses to cytoplasmic dsRNA are prevented. We propose that inosine bases are epigenetic marks identifying cellular RNA as innate immune ÒselfÓ. Consistent with this idea we show that an editing-active cytoplasmic ADAR is required to prevent aberrant immune responses in Adar1 mutant mouse embryo fibroblasts. No dramatic increase in repetitive transcripts is observed. AGS mutations in ADAR1 affect editing by the interferon-inducible cytoplasmic ADAR1 isoform. RNA-seq expression profiling in Adar1 and Adar1/Mavs knockout mice embryos.
2014-12-19 | E-GEOD-62917 | biostudies-arrayexpress
Project description:The project aims to evaluate the contribution of ADAR1 RNA editing to B cell lymphomagenesis, specifically in diffuse large B cell lymphoma (DLBCL). Within our DLBCL cohort, RNA editing targets transcripts within known lymphoma-driving pathways such as apoptosis, p53 and NF-kB signaling, as well as the previously unrecognized RIG-I-like pathway. In the latter context, we show that ADAR1-mediated editing in the MAVS transcript correlates with increased MAVS protein expression levels, associating with increased interferon/NF-kB signaling and increased T cell exhaustion. To confirm this mechanism, we have performed LC-MSMS analysis on a DLBCL cell line (RCK8) in the presence or absence of ADAR1 (Figure S11D ). Additionally, using targeted RNA base editing tools to restore editing within MAVS 3'UTR in ADAR1-deficient cells, we demonstrate that editing is likely to be causal to an increase in downstream signaling in the absence of activation by canonical nucleic acid receptor sensing. To confirm that this signaling increase depends on an increase of MAVS protein upon specific editing, we have performed LC-MSMS analysis on the same samples (Figure 4G).
2023-07-20 | PXD041549 | Pride
Project description:Adenosine deaminases acting on RNA (Adar1 and Adar2) catalyze I-to-A RNA editing, a post-transcriptional mechanism involved in multiple cellular functions. The role of Adar1-dependent RNA editing in cardiomyocytes (CMs) remains unclear. Here we show that conditional deletion of Adar1 in CMs results in myocarditis progressively evolving into dilated cardiomyopathy and heart failure at only 6 months of age. Adar1 depletion drives activation of interferon signaling genes (ISGs) in the absence of apoptosis and cytokine activation, and reduces the hypertrophic response of CMs upon pressure overload. Interestingly, ablation of the cytosolic sensor MDA5 prevents cardiac ISG activation and delays disease onset, but does not rescue the long-term lethal phenotype elicited by conditional deletion of Adar1. Retention of a single catalytically inactive Adar1 allele in CMs, in combination with MDA5 depletion, however, completely restores the cardiac function and prevents heart failure. Finally, ablation of interferon regulatory factor 7 (Irf7) attenuates the phenotype of Adar1-deficient CMs to a similar extent as MDA5 depletion, highlighting Irf7 as the main regulator of the immune response triggered by lack of Adar1 in CMs.
2022-08-24 | PXD024974 | Pride
Project description:ADAR1 is an interferon (IFN) inducible RNA editing enzyme that converts adenosine (A) to inosine (I). Here we identified ADAR1 and ADAR1p150 specific editing events by conducting RNA-seq on WT, ADAR1 KO, and ADAR1p150 KO cells.
2018-02-09 | GSE99249 | GEO
Project description:Purpose: RNA editing by ADAR1 is essential for hematopoietic development. The goals of this study were firstly, to identify ADAR1-specific RNA-editing sites by indentifying A-to-I (G) RNA editing sites in wild type mice that were not edited or reduced in editing frequency in ADAR1 deficient murine erythroid cells. Secondly, to determine the transcription consequence of an absence of ADAR1-mediated A-to-I editing. Methods: Total RNA from E14.5 fetal liver of embryos with an erythroid restricted deletion of ADAR1 (KO) and littermate controls (WT), in duplicate. cDNA libraries were prepared and RNA sequenced using Illumina HiSeq2000. The sequence reads that passed quality filters were analyzed at the transcript level with TopHat followed by Cufflinks. qRTâPCR validation was performed using SYBR Green assays. A-to-I (G) RNA editing sites were identified as previously described by Ramaswami G. et al., Nature Methods, 2012 using BurrowsâWheeler Aligner (BWA) followed by ANOVA (ANOVA). RNA editing sites were confirmed by Sanger sequencing. Results: Using an optimized data analysis workflow, we mapped about 30 million sequence reads per sample to the mouse genome (build mm9) and identified 14,484 transcripts in the fetal livers of WT and ADAR1E861A mice with BWA. RNA-seq data had a goodness of fit (R2) of >0.7, p<0.0001 between biological duplicates per genotype. Clusters of hyper-editing were onserved in long, unannotated 3'UTRs of erythroid specific transcripts. A profound upregulation of interferon stimulated genes were found to be massively upregulated (up to 5 log2FC) in KO fetal liver compared to WT. 11.332 (6,894 novel) A-to-I RNA editing sites were identified when assessing mismatches in RNA-seq data. Conclusions: Our study represents the first detailed analysis of erythroid transcriptomes and A-to-I RNA editing sites, with biologic replicates, generated by RNA-seq technology. A-to-I RNA editing is the essential function of ADAR1 and is required to prevent sensing of endogenous transcripts, likely via a RIG-I like receptor mediated axis. Fetal liver mRNA profiles of E14.5 wild type (WT) and ADAR Epor-Cre knock out mice were generated by deep sequencing, in duplicate using Illumina HiSeq 2000.
2016-07-24 | E-GEOD-71042 | biostudies-arrayexpress
Project description:Aberrant RNA-editing was observed in several human tumors, but its significance is mostly unknown. Here we show that ADAR1, a ubiquitous RNA-editing enzyme, is commonly lost in metastatic melanoma cells and specimens. Experimental ADAR1 silencing significantly alters melanoma cell morphology, facilitates proliferation and cell-cycle, and increases the tumorigenicity in-vivo. A series of ADAR1 truncation mutants establishes a novel RNA-editing-independent role for ADAR1 in controlling the nuclear and cytoplasmic processing steps of miRNA biogenesis. Altered expression of ADAR1-controled miRNAs accounts for the observed phenotype. We show that the oncogenic miR-17-5p endogenously regulates ADAR1 expression and that its genomic sequence is frequently amplified in melanoma to overexpress the mature miR-17-5p form. ADAR1 and miR-17-5p are ubiquitously expressed, suggesting the generality of this mechanism.
2012-08-31 | GSE31963 | GEO
Project description:Enterovirus infection has long been suspected as a possible trigger for type 1 diabetes. Upon infection, viral double-stranded RNA (dsRNA) is recognized by membrane and cytosolic sensors that orchestrate the type I interferon signaling and the recruitment of innate immune cells to the pancreatic islets. In this context, adenosine deaminase acting on RNA 1 (ADAR1) editing plays an important role in dampening the immune response by inducing adenosine mispairing, destabilizing the RNA duplexes and thus preventing an excessive immune activation. Here, we evaluated the role of ADAR1 in human pancreatic b cells and determined the impact of type 1 diabetes pathophysiological environment on ADAR1-dependent RNA editing. We show that both IFNα or IFNɣ/IL1β stimulation promotes ADAR1 expression and increases the A-to-I RNA editing of Alu-Containing mRNAs in EndoC-bH1 cells as well as primary human islets. We demonstrate that ADAR1 overexpression inhibits the type I interferon response signaling, while ADAR1 silencing potentiates IFNα effects. In addition, ADAR1 overexpression triggers the generation of alternative spliced RNAs, highlighting a novel role for ADAR1 as regulator of the b cell transcriptome under inflammatory conditions.
2022-11-23 | GSE214851 | GEO