Project description:Alternative splicing (AS) is particularly relevant to cancer progression and apoptosis. Although previous studies have shown that the apurinic-apyrimidinic endonuclease-1 (APEX1) is involved in tumor progression, it is unclear whether APEX1 can regulate AS on cell proliferation and apoptosis of Non-small-cell lung cancer (NSCLC). We performed a comprehensive analysis of the APEX1 expression in 517 lung NSCLC samples from the TCGA (Cancer Genome Atlas) database, and selected two sets of cancer samples with differentially expression APEX1 to analyze potential APEX1-regulated alternative splicing events (ASEs). Functional analysis of the APEX1 in A549 cells were performed in vitro. The APEX1 was overexpression in A549 cell by gene transfection. We identified AS targets regulated by APEX1, analyzed the GO biological process and KEGG functional pathways, and validated APEX1-regulated ASEs detected by RNA-seq and RT-PCR in A549 cells, then in clinical NSCLC samples these results were verified. The expression of the APEX1 was up-regulated in NSCLC samples, and overexpression of the APEX1 resulted in cell proliferation reduction and apoptosis induction. AS of many genes regulated by the APEX1 were enrich in cancer-related functional pathways. Results from A549 cell model and clinical samples showed that the MAPK signaling pathway, the Wnt signaling pathway were shared among the top ten enriched GO processes and KEGG functional pathways. According to our research, the validated AS events regulated by APEX1 mostly located in genes encoding transcription regulation factor in various signaling pathways, including the AXIN1 (axis inhibition protein 1), GCNT2 (N-acetyl glucosaminyl transferase 2), SMAD3 (SMAD Family Member 3), CTBP2 (C-Terminal Binding Protein 2). In this study, we successfully applied RNA-seq technology to demonstrate APEX1 regulation of AS. Our results underline that APEX1 was efficiently up-regulated in NSCLC samples, while overexpression of the APEX1 in A549 cells resulted in proliferation reduction and apoptosis induction. We confirm that the APEX1 regulates the AS of many genes which involved in cancer proliferation and apoptosis functional pathways, such as the MAPK signaling pathway and the Wnt signaling pathway, leading to mediate lung cancer progression. We found that high expression of the APEX1 in NSCLC is an independent prognostic factor related to tumor progression. Therefore, the APEX1 can serve as a molecular marker or therapeutic target for NSCLC treatment.
Project description:APEX1 overexpression and knockdown cell lines were established based on SKOV3 cell line. Lable-free quantitative phosphoproteomics was done to evaluate the impact of APEX1 on cellular phosphoproteomics
Project description:Self-renewal and differentiation of hematopoietic stem and progenitor cells (HSPCs) is carefully controlled by extrinsic and intrinsic factors, to ensure the lifelong process of hematopoiesis. Apurinic/apyrimidinic endonuclease 1 (APEX1) is a multifunctional protein implicated in DNA repair and transcriptional regulation. Although previous studies have emphasized the necessity of studying APEX1 in lineage-specific context and its role in some progenitor cells, no studies have assessed the role of APEX1, nor its two enzymatic domains, in supporting adult HSPC function. In this study, we demonstrated that complete loss of APEX1 from murine bone marrow HSPCs (induced by CRSIPR/Cas9) caused severe hematopoietic failure following transplantation, as well as an ex vivo HSPC expansion defect. Using specific inhibitors against either the nuclease or redox domains of APEX1 in combination with single cell transcriptomics (CITE-seq), we found that both APEX1 nuclease and redox domains are regulating mouse ex vivo HSPC proliferation, differentiation and survival, but through distinct mechanisms. Inhibition of the APEX1 nuclease function resulted in loss of HSPCs accompanied by early activation of differentiation programs and enhanced lineage commitment. By contrast, inhibition of the APEX1 redox function significantly downregulated interferon signaling in expanding HSPCs and their progeny, resulting in dysfunctional megakaryocyte-biased HSPCs, loss of monocytes and lymphoid progenitor cells. In conclusion, we demonstrate that APEX1 is a key regulator for adult regenerative hematopoiesis, and that the APEX1 nuclease and redox domains differentially impact lineage specification and stemness of functional ex vivo cultured HSPCs.
Project description:Sepsis is an exaggerated immune response upon infection with lipopolysaccharide (LPS) as the main causative agent. LPS-induced activation and apoptosis of endothelial cells (EC) can lead to organ dysfunction and finally organ failure. We have previously demonstrated that the first twenty amino acids of the Apurinic/Apyrimidinic Endodeoxyribonuclease 1 (APEX1) are sufficient to inhibit EC apoptosis. To identify genes whose regulation by LPS is affected by this N-terminal APEX1 peptide, EC were transduced with an expression vector for the APEX1 peptide or an empty control vector and treated with LPS. Following RNA deep sequencing, genes upregulated in LPS-treated EC expressing the APEX1 peptide were identified bioinformatically.
Project description:The bifunctional DNA glycosylases/AP lyases NEIL1 and NEIL2 excise oxidative base damages, but can also enhance the steady-state turnover of thymine DNA glycosylase (TDG) during oxidative DNA demethylation (Schomacher et al. 2016; doi:10.1038/nsmb.3151) probably due to their AP lyase activity during base excision repair (BER). The dual role of NEILs in antagonizing base damages and promoting epigenetic gene reactivation prompted us to investigate the consequences of Neil-deficiency during embryonic stem cell differentiation. For comparison stem cells deficient for Apex1, the bona fide AP endonuclease during BER, were analysed in parallel.
2019-09-16 | GSE130081 | GEO
Project description:A Rare Variant of ANK3 is Associated with Intracranial Aneurysm
Project description:<p>Garrod’s concept of “chemical individuality” has contributed to comprehension of the molecular origins of human diseases. Untargeted high-throughput metabolomic technologies provide an in-depth snapshot of human metabolism at scale. We studied the genetic architecture of the human plasma metabolome using 913 metabolites assayed in 19,994 individuals and identified 2,599 variant-metabolite associations (P<1.25x10^-11) within 330 genomic regions, with rare variants (MAF≤1%) explaining 9.4% of associations. Jointly modelling metabolites in each region, we identified 423 regional, co-regulated, variant-metabolite clusters called GIMs (Genetically Influenced Metabotypes). We assigned causal genes for 62.4% of GIMs, providing new insights into fundamental metabolite physiology and their clinical relevance, including metabolite guided discovery of potential adverse drug effects (<em>DPYD</em>, <em>SRD5A2</em>). We show strong enrichment of Inborn Errors of Metabolism (IEM)-causing genes, with examples of metabolite associations and clinical phenotypes of non-pathogenic variant carriers matching characteristics of IEMs. Systematic, phenotypic follow-up of metabolite-specific genetic scores revealed multiple potential aetiological relationships.</p><p><br></p><p><strong>EPIC-Norfolk study assays</strong> are reported in the current study <strong>MTBLS833</strong></p><p><strong>INTERVAL study assays</strong> are reported in <a href='https://www.ebi.ac.uk/metabolights/MTBLS834' rel='noopener noreferrer' target='_blank'><strong>MTBLS834</strong></a></p>
Project description:Brugada syndrome (BrS) is a cardiac arrhythmia disorder that causes sudden death in young adults. Rare genetic variants in the SCN5A gene, encoding the Nav1.5 sodium channel, and common non-coding variants at this locus, are robustly associated with the condition. BrS is particularly prevalent in Southeast Asia but the underlying ancestry-specific factors remain largely unknown. Methods: Genome sequencing of BrS probands and population-matched controls from Thailand was performed to identify rare non-coding variants at the SCN5A-SCN10A locus that were enriched in BrS cases. A likely causal variant was prioritised by computational methods and introduced into human pluripotent stem cell (hiPSC) lines using CRISPR-Cas9. The effect of the variant on SCN5A expression and Nav1.5 sodium channel current was then assessed in hiPSC-derived cardiomyocytes (hiPSC-CMs). Results: A rare non-coding variant in an SCN5A intronic enhancer region was highly enriched in BrS cases (detected in 3.9% of cases with a case-control odds ratio of 45.2). The variant affects a nucleotide conserved across all mammalian species and predicted to disrupt a Mef2 transcription factor binding site. Heterozygous introduction of the enhancer variant in hiPSC-CMs caused significantly reduced SCN5A expression from the variant-containing allele and a 30% reduction in Nav1.5-mediated sodium current density compared to isogenic controls, confirming its pathogenicity. Patients with the variant had severe phenotypes, with 89% experiencing cardiac arrest. Conclusions: This is the first example of a functionally validated rare non-coding variant at the SCN5A locus and highlights how genome sequencing in understudied populations can identify novel disease mechanisms. The variant partly explains the increased prevalence of BrS in this region and enables the identification of at-risk variant carriers to reduce the burden of sudden cardiac death in Thailand.
Project description:<p>Garrod’s concept of “chemical individuality” has contributed to comprehension of the molecular origins of human diseases. Untargeted high-throughput metabolomic technologies provide an in-depth snapshot of human metabolism at scale. We studied the genetic architecture of the human plasma metabolome using 913 metabolites assayed in 19,994 individuals and identified 2,599 variant-metabolite associations (P<1.25x10^-11) within 330 genomic regions, with rare variants (MAF≤1%) explaining 9.4% of associations. Jointly modelling metabolites in each region, we identified 423 regional, co-regulated, variant-metabolite clusters called GIMs (Genetically Influenced Metabotypes). We assigned causal genes for 62.4% of GIMs, providing new insights into fundamental metabolite physiology and their clinical relevance, including metabolite guided discovery of potential adverse drug effects (<em>DPYD</em>, <em>SRD5A2</em>). We show strong enrichment of Inborn Errors of Metabolism (IEM)-causing genes, with examples of metabolite associations and clinical phenotypes of non-pathogenic variant carriers matching characteristics of IEMs. Systematic, phenotypic follow-up of metabolite-specific genetic scores revealed multiple potential aetiological relationships.</p><p><br></p><p><strong>INTERVAL study assays</strong> are reported in the current study <strong>MTBLS834</strong></p><p><strong>EPIC-Norfolk study assays</strong> are reported in <a href='https://www.ebi.ac.uk/metabolights/MTBLS833' rel='noopener noreferrer' target='_blank'><strong>MTBLS833</strong></a></p>