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Nature Nov 2021Antibiotics are used to fight pathogens but also target commensal bacteria, disturbing the composition of gut microbiota and causing dysbiosis and disease. Despite this...
Antibiotics are used to fight pathogens but also target commensal bacteria, disturbing the composition of gut microbiota and causing dysbiosis and disease. Despite this well-known collateral damage, the activity spectrum of different antibiotic classes on gut bacteria remains poorly characterized. Here we characterize further 144 antibiotics from a previous screen of more than 1,000 drugs on 38 representative human gut microbiome species. Antibiotic classes exhibited distinct inhibition spectra, including generation dependence for quinolones and phylogeny independence for β-lactams. Macrolides and tetracyclines, both prototypic bacteriostatic protein synthesis inhibitors, inhibited nearly all commensals tested but also killed several species. Killed bacteria were more readily eliminated from in vitro communities than those inhibited. This species-specific killing activity challenges the long-standing distinction between bactericidal and bacteriostatic antibiotic classes and provides a possible explanation for the strong effect of macrolides on animal and human gut microbiomes. To mitigate this collateral damage of macrolides and tetracyclines, we screened for drugs that specifically antagonized the antibiotic activity against abundant Bacteroides species but not against relevant pathogens. Such antidotes selectively protected Bacteroides species from erythromycin treatment in human-stool-derived communities and gnotobiotic mice. These findings illluminate the activity spectra of antibiotics in commensal bacteria and suggest strategies to circumvent their adverse effects on the gut microbiota.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacteria, Anaerobic; Bacteroides; Clostridioides difficile; Dicumarol; Erythromycin; Feces; Female; Gastrointestinal Microbiome; Germ-Free Life; Humans; Macrolides; Male; Mice; Microbiota; Symbiosis; Tetracyclines
PubMed: 34646011
DOI: 10.1038/s41586-021-03986-2 -
Science Advances Mar 2023Following peripheral nerve injury, extracellular adenosine 5'-triphosphate (ATP)-mediated purinergic signaling is crucial for spinal cord microglia activation and...
Following peripheral nerve injury, extracellular adenosine 5'-triphosphate (ATP)-mediated purinergic signaling is crucial for spinal cord microglia activation and neuropathic pain. However, the mechanisms of ATP release remain poorly understood. Here, we show that volume-regulated anion channel (VRAC) is an ATP-releasing channel and is activated by inflammatory mediator sphingosine-1-phosphate (S1P) in microglia. Mice with microglia-specific deletion of Swell1 (also known as Lrrc8a), a VRAC essential subunit, had reduced peripheral nerve injury-induced increase in extracellular ATP in spinal cord. The mutant mice also exhibited decreased spinal microgliosis, dorsal horn neuronal hyperactivity, and both evoked and spontaneous neuropathic pain-like behaviors. We further performed high-throughput screens and identified an FDA-approved drug dicumarol as a novel and potent VRAC inhibitor. Intrathecal administration of dicumarol alleviated nerve injury-induced mechanical allodynia in mice. Our findings suggest that ATP-releasing VRAC in microglia is a key spinal cord determinant of neuropathic pain and a potential therapeutic target for this debilitating disease.
Topics: Mice; Animals; Peripheral Nerve Injuries; Microglia; Dicumarol; Neuralgia; Spinal Cord; Adenosine Triphosphate; Membrane Proteins
PubMed: 36989353
DOI: 10.1126/sciadv.ade9931 -
Journal of Hepatology Mar 2021Current antiviral therapies help keep HBV under control, but they are not curative, as they are unable to eliminate the intracellular viral replication intermediate...
BACKGROUND & AIMS
Current antiviral therapies help keep HBV under control, but they are not curative, as they are unable to eliminate the intracellular viral replication intermediate termed covalently closed circular DNA (cccDNA). Therefore, there remains an urgent need to develop strategies to cure CHB. Functional silencing of cccDNA is a crucial curative strategy that may be achieved by targeting the viral protein HBx.
METHODS
We screened 2,000 small-molecule compounds for their ability to inhibit HiBiT-tagged HBx (HiBiT-HBx) expression by using a HiBiT lytic detection system. The antiviral activity of a candidate compound and underlying mechanism of its effect on cccDNA transcription were evaluated in HBV-infected cells and a humanised liver mouse model.
RESULTS
Dicoumarol, an inhibitor of NAD(P)H:quinone oxidoreductase 1 (NQO1), significantly reduced HBx expression. Moreover, dicoumarol showed potent antiviral activity against HBV RNAs, HBV DNA, HBsAg and HBc protein in HBV-infected cells and a humanised liver mouse model. Mechanistic studies demonstrated that endogenous NQO1 binds to and protects HBx protein from 20S proteasome-mediated degradation. NQO1 knockdown or dicoumarol treatment significantly reduced the recruitment of HBx to cccDNA and inhibited the transcriptional activity of cccDNA, which was associated with the establishment of a repressive chromatin state. The absence of HBx markedly blocked the antiviral effect induced by NQO1 knockdown or dicoumarol treatment in HBV-infected cells.
CONCLUSIONS
Herein, we report on a novel small molecule that targets HBx to combat chronic HBV infection; we also reveal that NQO1 has a role in HBV replication through the regulation of HBx protein stability.
LAY SUMMARY
Current antiviral therapies for hepatitis B are not curative because of their inability to eliminate covalently closed circular DNA (cccDNA), which persists in the nuclei of infected cells. HBV X (HBx) protein has an important role in regulating cccDNA transcription. Thus, targeting HBx to silence cccDNA transcription could be an important curative strategy. We identified that the small molecule dicoumarol could block cccDNA transcription by promoting HBx degradation; this is a promising therapeutic strategy for the treatment of chronic hepatitis B.
Topics: Animals; Antiviral Agents; DNA, Circular; Dicumarol; Disease Models, Animal; Hep G2 Cells; Hepatitis B virus; Hepatitis B, Chronic; Hepatocytes; Humans; Mice; Mice, Inbred C57BL; Mice, Transgenic; NAD(P)H Dehydrogenase (Quinone); Proteolysis; Trans-Activators; Transcription, Genetic; Transfection; Treatment Outcome; Viral Regulatory and Accessory Proteins; Virus Replication
PubMed: 32987030
DOI: 10.1016/j.jhep.2020.09.019 -
Canadian Medical Association Journal Jul 1965
Topics: Anticoagulants; Dicumarol; Drug Therapy; Ethyl Biscoumacetate; Heparin; Humans; Phenindione; Warfarin
PubMed: 14313622
DOI: No ID Found -
British Medical Journal Nov 1947
Topics: Dicumarol
PubMed: 20271078
DOI: 10.1136/bmj.2.4531.748 -
British Medical Journal Mar 1948
Topics: Dicumarol
PubMed: 18902670
DOI: 10.1136/bmj.1.4548.475-c -
British Medical Journal Dec 1947
Topics: Dicumarol
PubMed: 20272462
DOI: 10.1136/bmj.2.4535.928-a -
British Medical Journal Jan 1948
Topics: Coumarins; Dicumarol
PubMed: 18921014
DOI: 10.1136/bmj.1.4541.125 -
British Medical Journal Dec 1947
Topics: Dicumarol
PubMed: 18935500
DOI: 10.1136/bmj.2.4537.1009-b -
Frontiers in Microbiology 2019is one of most pathogenic microorganisms in the world. Previously, the bifunctional enzyme GlmU with glucosamine-1-phosphate acetyltransferase activity and...
is one of most pathogenic microorganisms in the world. Previously, the bifunctional enzyme GlmU with glucosamine-1-phosphate acetyltransferase activity and -acetylglucosamine-1-phosphate uridyltransferase activity has been suggested as a potential drug target; therefore, discovering compounds targeting GlmU acetyltransferase is necessary. The natural products were tested for inhibition of GlmU acetyltransferase activity. We found that dicumarol exhibited inhibitory effects on GlmU acetyltransferase, with a concentration achieving a 50% inhibition (IC) value of 4.608 μg/ml (13.7 μM). The inhibition kinetics indicated that dicumarol uncompetitively inhibited acetyl CoA and showed mixed-type inhibition for glucosamine-1-phosphate (GlcN-1-P). The activity of dicumarol against H37Ra was evaluated with a minimum inhibitory concentration (MIC) value of 6.25 μg/ml (18.55 μM) in the Alamar blue assay. Dicumarol also exhibited inhibitory effects on several clinically sensitive strains and drug-resistant strains, with a range of MIC value of 6.25 to >100 μg/ml. Dicumarol increased the sensitivity of anti-tuberculosis drugs (isoniazid and rifampicin) when dicumarol was present at a low concentration. The transcriptome and proteome data of H37Ra treated by dicumarol showed that the affected genes were associated with cell wall synthesis, DNA damage and repair, metabolic processes, and signal transduction. These results provided the mechanism of dicumarol inhibition against GlmU acetyltransferase and and also suggested that dicumarol is a potential candidate for TB treatment.
PubMed: 31481936
DOI: 10.3389/fmicb.2019.01799