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MBio Feb 2023The purine-derived signaling molecules c-di-AMP and (p)ppGpp control /PBP2a-mediated β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) raise the...
The purine-derived signaling molecules c-di-AMP and (p)ppGpp control /PBP2a-mediated β-lactam resistance in methicillin-resistant Staphylococcus aureus (MRSA) raise the possibility that purine availability can control antibiotic susceptibility. Consistent with this, exogenous guanosine and xanthosine, which are fluxed through the GTP branch of purine biosynthesis, were shown to significantly reduce MRSA β-lactam resistance. In contrast, adenosine (fluxed to ATP) significantly increased oxacillin resistance, whereas inosine (which can be fluxed to ATP and GTP via hypoxanthine) only marginally increased oxacillin susceptibility. Furthermore, mutations that interfere with purine synthesis ( operon), transport (NupG, PbuG, PbuX) and the salvage pathway (DeoD2, Hpt) increased β-lactam resistance in MRSA strain JE2. Increased resistance of a mutant was not significantly reversed by guanosine, indicating that NupG is required for guanosine transport, which is required to reduce β-lactam resistance. Suppressor mutants resistant to oxacillin/guanosine combinations contained several purine salvage pathway mutations, including and . Guanosine significantly increased cell size and reduced levels of c-di-AMP, while inactivation of GdpP, the c-di-AMP phosphodiesterase negated the impact of guanosine on β-lactam susceptibility. PBP2a expression was unaffected in or mutants, suggesting that guanosine-induced β-lactam susceptibility may result from dysfunctional c-di-AMP-dependent osmoregulation. These data reveal the therapeutic potential of purine nucleosides, as β-lactam adjuvants that interfere with the normal activation of c-di-AMP are required for high-level β-lactam resistance in MRSA. The clinical burden of infections caused by antimicrobial resistant (AMR) pathogens is a leading threat to public health. Maintaining the effectiveness of existing antimicrobial drugs or finding ways to reintroduce drugs to which resistance is widespread is an important part of efforts to address the AMR crisis. Predominantly, the safest and most effective class of antibiotics are the β-lactams, which are no longer effective against methicillin-resistant Staphylococcus aureus (MRSA). Here, we report that the purine nucleosides guanosine and xanthosine have potent activity as adjuvants that can resensitize MRSA to oxacillin and other β-lactam antibiotics. Mechanistically, exposure of MRSA to these nucleosides significantly reduced the levels of the cyclic dinucleotide c-di-AMP, which is required for β-lactam resistance. Drugs derived from nucleotides are widely used in the treatment of cancer and viral infections highlighting the clinical potential of using purine nucleosides to restore or enhance the therapeutic effectiveness of β-lactams against MRSA and potentially other AMR pathogens.
Topics: Methicillin-Resistant Staphylococcus aureus; Purine Nucleosides; Bacterial Proteins; Anti-Bacterial Agents; Oxacillin; beta-Lactams; Monobactams; Guanosine; Adenosine Triphosphate; Guanosine Triphosphate; Microbial Sensitivity Tests; Penicillin-Binding Proteins; beta-Lactam Resistance
PubMed: 36507833
DOI: 10.1128/mbio.02478-22 -
Free Radical Biology & Medicine Mar 2022Heme-containing peroxidases catalyze the oxidation of a variety of substrates by consuming hydrogen peroxide (HO), and play diversified roles in physiology and pathology... (Review)
Review
Heme-containing peroxidases catalyze the oxidation of a variety of substrates by consuming hydrogen peroxide (HO), and play diversified roles in physiology and pathology including innate immunity, the synthesis of thyroid hormone and the extracellular matrix, as well as the pathogenesis of several inflammatory diseases. Peroxidasin (PXDN), also known as Vascular Peroxidase-1 (VPO1), is a newly identified peroxidase and expresses in multiple cells and tissues including cardiovascular system and the lung. Recent studies imply its roles in the innate immunity, cardiovascular physiology and diseases, and extracellular matrix formation. Studies on the role of PXDN in human diseases are entering a new and exciting stage, and this review provides the insights into this emerging field of PXDN.
Topics: Animals; Deoxyribonucleosides; Extracellular Matrix Proteins; Humans; Hydrogen Peroxide; Mammals; Peroxidase; Peroxidases; Purine Nucleosides; Peroxidasin
PubMed: 35219848
DOI: 10.1016/j.freeradbiomed.2022.02.026 -
Accounts of Chemical Research Oct 2023The function of cellular RNA is modulated by a host of post-transcriptional chemical modifications installed by dedicated RNA-modifying enzymes. RNA modifications are...
The function of cellular RNA is modulated by a host of post-transcriptional chemical modifications installed by dedicated RNA-modifying enzymes. RNA modifications are widespread in biology, occurring in all kingdoms of life and in all classes of RNA molecules. They regulate RNA structure, folding, and protein-RNA interactions, and have important roles in fundamental gene expression processes involving mRNA, tRNA, rRNA, and other types of RNA species. Our understanding of RNA modifications has advanced considerably; however, there are still many outstanding questions regarding the distribution of modifications across all RNA transcripts and their biological function. One of the major challenges in the study of RNA modifications is the lack of sequencing methods for the transcriptome-wide mapping of different RNA-modification structures. Furthermore, we lack general strategies to characterize RNA-modifying enzymes and RNA-modification reader proteins. Therefore, there is a need for new approaches to enable integrated studies of RNA-modification chemistry and biology.In this Account, we describe our development and application of chemoproteomic strategies for the study of RNA-modification-associated proteins. We present two orthogonal methods based on nucleoside and oligonucleotide chemical probes: 1) RNA-mediated activity-based protein profiling (RNABPP), a metabolic labeling strategy based on reactive modified nucleoside probes to profile RNA-modifying enzymes in cells and 2) photo-cross-linkable diazirine-containing synthetic oligonucleotide probes for identifying RNA-modification reader proteins.We use RNABPP with C5-modified cytidine and uridine nucleosides to capture diverse RNA-pyrimidine-modifying enzymes including methyltransferases, dihydrouridine synthases, and RNA dioxygenase enzymes. Metabolic labeling facilitates the mechanism-based cross-linking of RNA-modifying enzymes with their native RNA substrates in cells. Covalent RNA-protein complexes are then isolated by denaturing oligo(dT) pulldown, and cross-linked proteins are identified by quantitative proteomics. Once suitable modified nucleosides have been identified as mechanism-based proteomic probes, they can be further deployed in transcriptome-wide sequencing experiments to profile the substrates of RNA-modifying enzymes at nucleotide resolution. Using 5-fluorouridine-mediated RNA-protein cross-linking and sequencing, we analyzed the substrates of human dihydrouridine synthase DUS3L. 5-Ethynylcytidine-mediated cross-linking enabled the investigation of ALKBH1 substrates. We also characterized the functions of these RNA-modifying enzymes in human cells by using genetic knockouts and protein translation reporters.We profiled RNA readers for -methyladenosine (mA) and -methyladenosine (mA) using a comparative proteomic workflow based on diazirine-containing modified oligonucleotide probes. Our approach enables quantitative proteome-wide analysis of the preference of RNA-binding proteins for modified nucleotides across a range of affinities. Interestingly, we found that YTH-domain proteins YTHDF1/2 can bind to both mA and mA to mediate transcript destabilization. Furthermore, mA also inhibits stress granule proteins from binding to RNA.Taken together, we demonstrate the application of chemical probing strategies, together with proteomic and transcriptomic workflows, to reveal new insights into the biological roles of RNA modifications and their associated proteins.
Topics: Humans; Nucleosides; Adenosine; Proteomics; Diazomethane; Oligonucleotide Probes; RNA; AlkB Homolog 1, Histone H2a Dioxygenase
PubMed: 37733063
DOI: 10.1021/acs.accounts.3c00450 -
Frontiers in Bioscience (Landmark... Nov 2022The N6-methyladenosine (m6A) is the most abundant internal modification in advanced eukaryotic mRNAs, and it plays an important role in mRNA metabolism and diverse... (Review)
Review
The N6-methyladenosine (m6A) is the most abundant internal modification in advanced eukaryotic mRNAs, and it plays an important role in mRNA metabolism and diverse biological processes. Moreover, m6A modification is dynamically reversible and may reshape gene expression patterns after demethylation induced by drug interventions, which may reverse the occurrence and progression of certain diseases. Although the role of changes in DNA methylation in ophthalmic diseases has been well described, the regulatory role of the m6A modification in ophthalmic diseases is still a new field of study. This paper aims to systematically summarize the latest research progress about m6a-modification-related ophthalmic diseases and potential therapeutic strategies. All English literature relevant to our research was searched in PubMed and CNKI databases, using appropriate keywords. Our study reviews the regulatory role of m6A in ophthalmic diseases. It covers almost all of the reported m6A-related ophthalmic diseases and proposes potential treatment strategies for each disease. This review will provide direction for further research on m6A in ophthalmic diseases and help in the treatment of ophthalmic diseases in the future.
Topics: Adenosine; DNA Methylation; Eukaryota; Eukaryotic Cells
PubMed: 36472104
DOI: 10.31083/j.fbl2711304 -
Haematologica Jan 2024
Topics: Humans; Adenosine
PubMed: 37470140
DOI: 10.3324/haematol.2023.283469 -
Cell Communication and Signaling : CCS Sep 2022N6-methyl-adenosine (mA) is the most prevalent modification on mRNAs and long noncoding RNAs (lnRNAs) in higher eukaryotes. Modulation of mA relies on mA writers,... (Review)
Review
N6-methyl-adenosine (mA) is the most prevalent modification on mRNAs and long noncoding RNAs (lnRNAs) in higher eukaryotes. Modulation of mA relies on mA writers, erasers and readers. mA modification contributes to diverse fundamental biological functions at the molecular, cellular, and physiological levels. The dysregulation of mA modification has been implicated in various human diseases. Thus, mA modification has now become a research hotspot for its potential therapeutic applications in the treatment of various cancers and diseases. The immune system is essential to provide defense against infections and cancers. This review summarizes the current knowledge about the roles of mA in regulating immune cell functions and immune responses. Video abstract.
Topics: Adenosine; Humans; Methylation; Methyltransferases; Neoplasms
PubMed: 36085064
DOI: 10.1186/s12964-022-00939-8 -
Journal of Hematology & Oncology Jul 2021N6-methyladenosine (m6A) has emerged as an abundant modification throughout the transcriptome with widespread functions in protein-coding and noncoding RNAs. It affects... (Review)
Review
N6-methyladenosine (m6A) has emerged as an abundant modification throughout the transcriptome with widespread functions in protein-coding and noncoding RNAs. It affects the fates of modified RNAs, including their stability, splicing, and/or translation, and thus plays important roles in posttranscriptional regulation. To date, m6A methyltransferases have been reported to execute m6A deposition on distinct RNAs by their own or forming different complexes with additional partner proteins. In this review, we summarize the function of these m6A methyltransferases or complexes in regulating the key genes and pathways of cancer biology. We also highlight the progress in the use of m6A methyltransferases in mediating therapy resistance, including chemotherapy, targeted therapy, immunotherapy and radiotherapy. Finally, we discuss the current approaches and clinical potential of m6A methyltransferase-targeting strategies.
Topics: Adenosine; Animals; Gene Expression Regulation, Neoplastic; Humans; Methyltransferases; Molecular Targeted Therapy; Neoplasms; Signal Transduction
PubMed: 34315512
DOI: 10.1186/s13045-021-01129-8 -
Redox Biology Nov 2021Purinergic signaling is a cell communication pathway mediated by extracellular nucleotides and nucleosides. Tri- and diphosphonucleotides are released in physiological... (Review)
Review
Purinergic signaling is a cell communication pathway mediated by extracellular nucleotides and nucleosides. Tri- and diphosphonucleotides are released in physiological and pathological circumstances activating purinergic type 2 receptors (P2 receptors): P2X ion channels and P2Y G protein-coupled receptors. The activation of these receptors triggers the production of reactive oxygen and nitrogen species and alters antioxidant defenses, modulating the redox biology of cells. The activation of P2 receptors is controlled by ecto-enzymes named ectonucleotidases, E-NTPDase1/CD39 and ecto-5'-nucleotidase/CD73) being the most relevant. The first enzyme hydrolyzes adenosine triphosphate (ATP) and adenosine diphosphate (ADP) into adenosine monophosphate (AMP), and the second catalyzes the hydrolysis of AMP to adenosine. The activity of these enzymes is diminished by oxidative stress. Adenosine actives P1 G-coupled receptors that, in general, promote the maintenance of redox hemostasis by decreasing reactive oxygen species (ROS) production and increase antioxidant enzymes. Intracellular purine metabolism can also contribute to ROS generation via xanthine oxidase activity, which converts hypoxanthine into xanthine, and finally, uric acid. In this review, we describe the mechanisms of redox biology modulated by purinergic signaling and how this signaling may be affected by disturbances in the redox homeostasis of cells.
Topics: Adenosine; Adenosine Diphosphate; Adenosine Triphosphate; Biology; Oxidation-Reduction
PubMed: 34563872
DOI: 10.1016/j.redox.2021.102137 -
BioMed Research International 2020Equilibrative nucleoside transporter 2 (ENT2) is a bidirectional transporter embedded in the biological membrane and is ubiquitously found in most tissue and cell types.... (Review)
Review
Equilibrative nucleoside transporter 2 (ENT2) is a bidirectional transporter embedded in the biological membrane and is ubiquitously found in most tissue and cell types. ENT2 mediates the uptake of purine and pyrimidine nucleosides and nucleobase besides transporting a variety of nucleoside-derived drugs, mostly in anticancer therapy. Since high expression of ENT2 has been correlated with advanced stages of different types of cancers, consequently, this has gained significant interest in the role of ENT2 as a potential therapeutic target. Furthermore, ENT2 plays critical roles in signaling pathway and cell cycle progression. Therefore, elucidating the physiological roles of ENT2 and its properties may contribute to a better understanding of ENT2 roles beyond their transportation mechanism. This review is aimed at highlighting the main roles of ENT2 and at providing a brief update on the recent research.
Topics: Adenosine; Animals; Antineoplastic Agents; Biological Transport; Biomarkers; Cell Cycle; Cell Line, Tumor; Cell Membrane; Equilibrative-Nucleoside Transporter 2; Glycosylation; Humans; Mice; Neoplasms; Nucleosides; Rabbits; Rats; Signal Transduction
PubMed: 33344638
DOI: 10.1155/2020/5197626 -
International Journal of Molecular... Jan 2023The purine signaling system is represented by purine and pyrimidine nucleotides and nucleosides that exert their effects through the adenosine, P2X and P2Y receptor... (Review)
Review
The purine signaling system is represented by purine and pyrimidine nucleotides and nucleosides that exert their effects through the adenosine, P2X and P2Y receptor families. It is known that, under physiological conditions, P2 receptors play only a minor role in modulating the functions of cells and systems; however, their role significantly increases under some pathophysiological conditions, such as stress, ischemia or hypothermia, when they can play a dominant role as a signaling molecule. The diversity of P2 receptors and their wide distribution in the body make them very attractive as a target for the pharmacological action of drugs with a new mechanism of action. The review is devoted to the involvement of P2 signaling in the development of pathologies associated with a loss of muscle mass. The contribution of adenosine triphosphate (ATP) as a signal molecule in the pathogenesis of a number of muscular dystrophies (Duchenne, Becker and limb girdle muscular dystrophy 2B) is considered. To understand the processes involving the purinergic system, the role of the ATP and P2 receptors in several models associated with skeletal muscle degradation is also discussed.
Topics: Humans; Receptors, Purinergic P2; Adenosine Triphosphate; Muscular Dystrophies; Adenosine; Signal Transduction
PubMed: 36675094
DOI: 10.3390/ijms24021587