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Cell Death & Disease Jun 2024TGF-β1 plays a pivotal role in the metastatic cascade of malignant neoplasms. N6-methyladenosine (mA) stands as one of the most abundant modifications on the mRNA...
TGF-β1 plays a pivotal role in the metastatic cascade of malignant neoplasms. N6-methyladenosine (mA) stands as one of the most abundant modifications on the mRNA transcriptome. However, in the metastasis of gallbladder carcinoma (GBC), the effect of TGF-β1 with mRNA mA modification, especially the effect of mRNA translation efficiency associated with mA modification, remains poorly elucidated. Here we demonstrated a negative correlation between FOXA1 and TGF-β1 expression in GBC. Overexpression of FOXA1 inhibited TGF-β1-induced migration and epithelial-mesenchymal transition (EMT) in GBC cells. Mechanistically, we confirmed that TGF-β1 suppressed the translation efficiency of FOXA1 mRNA through polysome profiling analysis. Importantly, both in vivo and in vitro experiments showed that TGF-β1 promoted mA modification on the coding sequence (CDS) region of FOXA1 mRNA, which was responsible for the inhibition of FOXA1 mRNA translation by TGF-β1. We demonstrated through MeRIP and RIP assays, dual-luciferase reporter assays and site-directed mutagenesis that ALKBH5 promoted FOXA1 protein expression by inhibiting mA modification on the CDS region of FOXA1 mRNA. Moreover, TGF-β1 inhibited the binding capacity of ALKBH5 to the FOXA1 CDS region. Lastly, our study confirmed that overexpression of FOXA1 suppressed lung metastasis and EMT in a nude mice lung metastasis model. In summary, our research findings underscore the role of TGF-β1 in regulating TGF-β1/FOXA1-induced GBC EMT and metastasis by inhibiting FOXA1 translation efficiency through mA modification.
Topics: Hepatocyte Nuclear Factor 3-alpha; Humans; Transforming Growth Factor beta1; Gallbladder Neoplasms; Animals; Epithelial-Mesenchymal Transition; Cell Line, Tumor; Adenosine; Mice, Nude; Mice; Protein Biosynthesis; Neoplasm Metastasis; Gene Expression Regulation, Neoplastic; Cell Movement; RNA, Messenger; Mice, Inbred BALB C; Male
PubMed: 38886389
DOI: 10.1038/s41419-024-06800-9 -
Nature Communications Jun 2024Methylenetetrahydrofolate reductase (MTHFR) is a pivotal flavoprotein connecting the folate and methionine methyl cycles, catalyzing the conversion of...
Methylenetetrahydrofolate reductase (MTHFR) is a pivotal flavoprotein connecting the folate and methionine methyl cycles, catalyzing the conversion of methylenetetrahydrofolate to methyltetrahydrofolate. Human MTHFR (hMTHFR) undergoes elaborate allosteric regulation involving protein phosphorylation and S-adenosylmethionine (AdoMet)-dependent inhibition, though other factors such as subunit orientation and FAD status remain understudied due to the lack of a functional structural model. Here, we report crystal structures of Chaetomium thermophilum MTHFR (cMTHFR) in both active (R) and inhibited (T) states. We reveal FAD occlusion by Tyr361 in the T-state, which prevents substrate interaction. Remarkably, the inhibited form of cMTHFR accommodates two AdoMet molecules per subunit. In addition, we conducted a detailed investigation of the phosphorylation sites in hMTHFR, three of which were previously unidentified. Based on the structural framework provided by our cMTHFR model, we propose a possible mechanism to explain the allosteric structural transition of MTHFR, including the impact of phosphorylation on AdoMet-dependent inhibition.
Topics: Methylenetetrahydrofolate Reductase (NADPH2); S-Adenosylmethionine; Allosteric Regulation; Chaetomium; Phosphorylation; Humans; Crystallography, X-Ray; Models, Molecular; Flavin-Adenine Dinucleotide
PubMed: 38886362
DOI: 10.1038/s41467-024-49327-5 -
Clinical and Translational Medicine Jun 2024Dysregulated RNA modifications, stemming from the aberrant expression and/or malfunction of RNA modification regulators operating through various pathways, play pivotal... (Review)
Review
Dysregulated RNA modifications, stemming from the aberrant expression and/or malfunction of RNA modification regulators operating through various pathways, play pivotal roles in driving the progression of haematological malignancies. Among RNA modifications, N-methyladenosine (mA) RNA modification, the most abundant internal mRNA modification, stands out as the most extensively studied modification. This prominence underscores the crucial role of the layer of epitranscriptomic regulation in controlling haematopoietic cell fate and therefore the development of haematological malignancies. Additionally, other RNA modifications (non-mA RNA modifications) have gained increasing attention for their essential roles in haematological malignancies. Although the roles of the mA modification machinery in haematopoietic malignancies have been well reviewed thus far, such reviews are lacking for non-mA RNA modifications. In this review, we mainly focus on the roles and implications of non-mA RNA modifications, including N-acetylcytidine, pseudouridylation, 5-methylcytosine, adenosine to inosine editing, 2'-O-methylation, N-methyladenosine and N-methylguanosine in haematopoietic malignancies. We summarise the regulatory enzymes and cellular functions of non-mA RNA modifications, followed by the discussions of the recent studies on the biological roles and underlying mechanisms of non-mA RNA modifications in haematological malignancies. We also highlight the potential of therapeutically targeting dysregulated non-mA modifiers in blood cancer.
Topics: Humans; Hematologic Neoplasms; RNA Processing, Post-Transcriptional; RNA; Adenosine
PubMed: 38880983
DOI: 10.1002/ctm2.1666 -
Nature Communications Jun 2024Glucagon, a hormone released from pancreatic α-cells, is critical for maintaining euglycemia and plays a key role in the pathophysiology of diabetes. To stimulate the...
Glucagon, a hormone released from pancreatic α-cells, is critical for maintaining euglycemia and plays a key role in the pathophysiology of diabetes. To stimulate the development of new classes of therapeutic agents targeting glucagon release, key α-cell signaling pathways that regulate glucagon secretion need to be identified. Here, we focused on the potential importance of α-cell G signaling on modulating α-cell function. Studies with α-cell-specific mouse models showed that activation of α-cell G signaling causes a marked increase in glucagon secretion. We also found that intra-islet adenosine plays an unexpected autocrine/paracrine role in promoting glucagon release via activation of α-cell G-coupled A adenosine receptors. Studies with α-cell-specific Gα knockout mice showed that α-cell G also plays an essential role in stimulating the activity of the Gcg gene, thus ensuring proper islet glucagon content. Our data suggest that α-cell enriched G-coupled receptors represent potential targets for modulating α-cell function for therapeutic purposes.
Topics: Glucagon; Animals; Glucagon-Secreting Cells; Signal Transduction; Mice, Knockout; Mice; GTP-Binding Protein alpha Subunits, Gs; Adenosine; Receptor, Adenosine A2A; Male; Mice, Inbred C57BL; Islets of Langerhans
PubMed: 38879678
DOI: 10.1038/s41467-024-49537-x -
Proceedings of the National Academy of... Jun 2024Human bocavirus 1 (HBoV1) is a human parvovirus that causes lower respiratory tract infections in young children. It contains a single-stranded (ss) DNA genome of ~5.5...
Human bocavirus 1 (HBoV1) is a human parvovirus that causes lower respiratory tract infections in young children. It contains a single-stranded (ss) DNA genome of ~5.5 kb that encodes a small noncoding RNA of 140 nucleotides known as bocavirus-encoded small RNA (BocaSR), in addition to viral proteins. Here, we determined the secondary structure of BocaSR in vivo by using DMS-MaPseq. Our findings reveal that BocaSR undergoes N6-methyladenosine (m6A) modification at multiple sites, which is critical for viral DNA replication in both dividing HEK293 cells and nondividing cells of the human airway epithelium. Mechanistically, we found that m6A-modified BocaSR serves as a mediator for recruiting Y-family DNA repair DNA polymerase (Pol) η and Pol κ likely through a direct interaction between BocaSR and the viral DNA replication origin at the right terminus of the viral genome. Thus, this report represents direct involvement of a viral small noncoding RNA in viral DNA replication through m6A modification.
Topics: Humans; Adenosine; Virus Replication; DNA-Directed DNA Polymerase; DNA Replication; DNA, Viral; HEK293 Cells; RNA, Viral; Human bocavirus; Genome, Viral; Parvoviridae Infections
PubMed: 38875150
DOI: 10.1073/pnas.2320782121 -
Frontiers in Immunology 2024Immunotherapy for hematological malignancies is a rapidly advancing field that has gained momentum in recent years, primarily encompassing chimeric antigen receptor... (Review)
Review
Immunotherapy for hematological malignancies is a rapidly advancing field that has gained momentum in recent years, primarily encompassing chimeric antigen receptor T-cell (CAR-T) therapies, immune checkpoint inhibitors, and other modalities. However, its clinical efficacy remains limited, and drug resistance poses a significant challenge. Therefore, novel immunotherapeutic targets and agents need to be identified. Recently, N6-methyladenosine (m6A), the most prevalent RNA epitope modification, has emerged as a pivotal factor in various malignancies. Reportedly, m6A mutations influence the immunological microenvironment of hematological malignancies, leading to immune evasion and compromising the anti-tumor immune response in hematological malignancies. In this review, we comprehensively summarize the roles of the currently identified m6A modifications in various hematological malignancies, with a particular focus on their impact on the immune microenvironment. Additionally, we provide an overview of the research progress made in developing m6A-targeted drugs for hematological tumor therapy, to offer novel clinical insights.
Topics: Humans; Tumor Microenvironment; Hematologic Neoplasms; Adenosine; Animals; Immunotherapy
PubMed: 38868768
DOI: 10.3389/fimmu.2024.1374390 -
The Journal of Physiological Sciences :... Jun 2024Hibernation and torpor are not passive responses caused by external temperature drops and fasting but are active brain functions that lower body temperature. A...
Hibernation and torpor are not passive responses caused by external temperature drops and fasting but are active brain functions that lower body temperature. A population of neurons in the preoptic area was recently identified as such active torpor-regulating neurons. We hypothesized that the other hypothermia-inducing maneuvers would also activate these neurons. To test our hypothesis, we first refined the previous observations, examined the brain regions explicitly activated during the falling phase of body temperature using c-Fos expression, and confirmed the preoptic area. Next, we observed long-lasting hypothermia by reactivating torpor-tagged Gq-expressing neurons using the activity tagging and DREADD systems. Finally, we found that about 40-60% of torpor-tagged neurons were activated by succeeding isoflurane anesthesia and by icv administration of an adenosine A1 agonist. Isoflurane-induced and central adenosine-induced hypothermia is, at least in part, an active process mediated by the torpor-regulating neurons in the preoptic area.
Topics: Animals; Preoptic Area; Isoflurane; Adenosine; Neurons; Male; Anesthetics, Inhalation; Body Temperature; Hypothermia; Torpor; Mice; Proto-Oncogene Proteins c-fos
PubMed: 38867187
DOI: 10.1186/s12576-024-00927-2 -
Nature Communications Jun 2024Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease due to gradual motoneurons (MN) degeneration. Among the processes associated to ALS...
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease due to gradual motoneurons (MN) degeneration. Among the processes associated to ALS pathogenesis, there is the formation of cytoplasmic inclusions produced by aggregation of mutant proteins, among which the RNA binding protein FUS. Here we show that, in neuronal cells and in iPSC-derived MN expressing mutant FUS, such inclusions are significantly reduced in number and dissolve faster when the RNA mA content is diminished. Interestingly, stress granules formed in ALS conditions showed a distinctive transcriptome with respect to control cells, which reverted to similar to control after mA downregulation. Notably, cells expressing mutant FUS were characterized by higher mA levels suggesting a possible link between mA homeostasis and pathological aggregates. Finally, we show that FUS inclusions are reduced also in patient-derived fibroblasts treated with STM-2457, an inhibitor of METTL3 activity, paving the way for its possible use for counteracting aggregate formation in ALS.
Topics: RNA-Binding Protein FUS; Amyotrophic Lateral Sclerosis; Humans; Motor Neurons; Induced Pluripotent Stem Cells; Cytoplasmic Granules; Fibroblasts; Adenosine; Methyltransferases; Mutation; Inclusion Bodies; Stress Granules; Transcriptome
PubMed: 38866783
DOI: 10.1038/s41467-024-49416-5 -
BMJ (Clinical Research Ed.) Jun 2024To assess the effect of different antiplatelet strategies on clinical outcomes after coronary artery bypass grafting. (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVE
To assess the effect of different antiplatelet strategies on clinical outcomes after coronary artery bypass grafting.
DESIGN
Five year follow-up of randomised Different Antiplatelet Therapy Strategy After Coronary Artery Bypass Grafting (DACAB) trial.
SETTING
Six tertiary hospitals in China; enrolment between July 2014 and November 2015; completion of five year follow-up from August 2019 to June 2021.
PARTICIPANTS
500 patients aged 18-80 years (including 91 (18.2%) women) who had elective coronary artery bypass grafting surgery and completed the DACAB trial.
INTERVENTIONS
Patients were randomised 1:1:1 to ticagrelor 90 mg twice daily plus aspirin 100 mg once daily (dual antiplatelet therapy; n=168), ticagrelor monotherapy 90 mg twice daily (n=166), or aspirin monotherapy 100 mg once daily (n=166) for one year after surgery. After the first year, antiplatelet therapy was prescribed according to standard of care by treating physicians.
MAIN OUTCOME MEASURES
The primary outcome was major adverse cardiovascular events (a composite of all cause death, myocardial infarction, stroke, and coronary revascularisation), analysed using the intention-to-treat principle. Time-to-event analysis was used to compare the risk between treatment groups. Multiple post hoc sensitivity analyses examined the robustness of the findings.
RESULTS
Follow-up at five years for major adverse cardiovascular events was completed for 477 (95.4%) of 500 patients; 148 patients had major adverse cardiovascular events, including 39 in the dual antiplatelet therapy group, 54 in the ticagrelor monotherapy group, and 55 in the aspirin monotherapy group. Risk of major adverse cardiovascular events at five years was significantly lower with dual antiplatelet therapy versus aspirin monotherapy (22.6% 29.9%; hazard ratio 0.65, 95% confidence interval 0.43 to 0.99; P=0.04) and versus ticagrelor monotherapy (22.6% 32.9%; 0.66, 0.44 to 1.00; P=0.05). Results were consistent in all sensitivity analyses.
CONCLUSIONS
Treatment with ticagrelor dual antiplatelet therapy for one year after surgery reduced the risk of major adverse cardiovascular events at five years after coronary artery bypass grafting compared with aspirin monotherapy or ticagrelor monotherapy.
TRIAL REGISTRATION
NCT03987373ClinicalTrials.gov NCT03987373.
Topics: Humans; Coronary Artery Bypass; Platelet Aggregation Inhibitors; Female; Male; Middle Aged; Ticagrelor; Aspirin; Aged; Follow-Up Studies; Adult; Aged, 80 and over; Drug Therapy, Combination; Adolescent; Postoperative Complications; Treatment Outcome; Young Adult; China; Dual Anti-Platelet Therapy
PubMed: 38862179
DOI: 10.1136/bmj-2023-075707 -
Cell Death & Disease Jun 2024Diabetic cardiomyopathy (DCM) is a prevalent myocardial microvascular complication of the myocardium with a complex pathogenesis. Investigating the pathogenesis of DCM...
Diabetic cardiomyopathy (DCM) is a prevalent myocardial microvascular complication of the myocardium with a complex pathogenesis. Investigating the pathogenesis of DCM can significantly contribute to enhancing its prevention and treatment strategies. Our study revealed an upregulation of lysine acetyltransferase 2 A (Kat2a) expression in DCM, accompanied by a decrease in N6-methyladenosine (m6A) modified Kat2a mRNA levels. Our study revealed an upregulation of lysine acetyltransferase 2 A (Kat2a) expression in DCM, accompanied by a decrease in N6-methyladenosine (m6A) modified Kat2a mRNA levels. Functionally, inhibition of Kat2a effectively ameliorated high glucose-induced cardiomyocyte injury both in vitro and in vivo by suppressing ferroptosis. Mechanistically, Demethylase alkB homolog 5 (Alkbh5) was found to reduce m6A methylation levels on Kat2a mRNA, leading to its upregulation. YTH domain family 2 (Ythdf2) played a crucial role as an m6A reader protein mediating the degradation of Kat2a mRNA. Furthermore, Kat2a promoted ferroptosis by increasing Tfrc and Hmox1 expression via enhancing the enrichment of H3K27ac and H3K9ac on their promoter regions. In conclusion, our findings unveil a novel role for the Kat2a-ferroptosis axis in DCM pathogenesis, providing valuable insights for potential clinical interventions.
Topics: Diabetic Cardiomyopathies; Animals; Ferroptosis; Humans; Heme Oxygenase-1; Mice; Histone Acetyltransferases; Male; Mice, Inbred C57BL; Myocytes, Cardiac; Membrane Proteins; Adenosine
PubMed: 38858351
DOI: 10.1038/s41419-024-06771-x