dicumarol and Disease-Models--Animal

Topics: Animals; Blood Platelets; Blood Vessel Prosthesis; Blood Vessels; Dicumarol; Disease Models, Animal; Fibrin; Formaldehyde; Heparin; Laser Therapy; Platelet Adhesiveness; Rabbits; Rats; Sclerosing Solutions; Thrombosis

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.. 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.. 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.. 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.. 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; Dicumarol; Disease Models, Animal; DNA, Circular; 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

When Zika virus emerged as a public health emergency there were no drugs or vaccines approved for its prevention or treatment. We used a high-throughput screen for Zika virus protease inhibitors to identify several inhibitors of Zika virus infection. We expressed the NS2B-NS3 Zika virus protease and conducted a biochemical screen for small-molecule inhibitors. A quantitative structure-activity relationship model was employed to virtually screen ∼138,000 compounds, which increased the identification of active compounds, while decreasing screening time and resources. Candidate inhibitors were validated in several viral infection assays. Small molecules with favorable clinical profiles, especially the five-lipoxygenase-activating protein inhibitor, MK-591, inhibited the Zika virus protease and infection in neural stem cells. Members of the tetracycline family of antibiotics were more potent inhibitors of Zika virus infection than the protease, suggesting they may have multiple mechanisms of action. The most potent tetracycline, methacycline, reduced the amount of Zika virus present in the brain and the severity of Zika virus-induced motor deficits in an immunocompetent mouse model. As Food and Drug Administration-approved drugs, the tetracyclines could be quickly translated to the clinic. The compounds identified through our screening paradigm have the potential to be used as prophylactics for patients traveling to endemic regions or for the treatment of the neurological complications of Zika virus infection.

Topics: Animals; Antiviral Agents; Artificial Intelligence; Chlorocebus aethiops; Disease Models, Animal; Drug Evaluation, Preclinical; High-Throughput Screening Assays; Immunocompetence; Inhibitory Concentration 50; Methacycline; Mice, Inbred C57BL; Protease Inhibitors; Quantitative Structure-Activity Relationship; Small Molecule Libraries; Vero Cells; Zika Virus; Zika Virus Infection

Dopamine oxidation in the pathway leading to neuromelanin formation generates the ortho-quinone aminochrome, which is potentially neurotoxic but normally rapidly converted by DT-diaphorase to nontoxic leukoaminochrome. However, when administered exogenously into rat striatum, aminochrome is able to produce damage to dopaminergic neurons. Because of a recent report that substantia nigra pars compacta (SNpc) tyrosine hydroxylase (T-OH) levels were unaltered by aminochrome when there was cell shrinkage of dopaminergic neurons along with a reduction in striatal dopamine release, the following study was conducted to more accurately determine the role of DT-diaphorase in aminochrome neurotoxicity. In this study, a low dose of aminochrome (0.8 nmol) with or without the DT-diaphorase inhibitor dicoumarol (0.2 nmol) was injected into the left striatum of rats. Intrastriatal 6-hydroxydopamine (6-OHDA, 32 nmol) was used as a positive neurotoxin control in other rats. Two weeks later, there was significant loss in numbers of T-OH immunoreactive fibers in SNpc, also a loss in cell density in SNpc, and prominent apomorphine (0.5 mg/kg sc)-induced contralateral rotations in rats that had been treated with aminochrome, with aminochrome/dicoumarol, or with 6-OHDA. Findings demonstrate that neurotoxic aminochrome is able to exert neurotoxicity only when DT-diaphorase is suppressed-implying that DT-diaphorase is vital in normally suppressing toxicity of in vivo aminochrome, generated in the pathway towards neuromelanin formation.

Topics: Animals; Dicumarol; Disease Models, Animal; Enzyme Inhibitors; Indolequinones; Male; NAD(P)H Dehydrogenase (Quinone); Neurotoxicity Syndromes; Neurotoxins; Oxidation-Reduction; Rats; Rats, Sprague-Dawley; Stereotaxic Techniques; Tyrosine 3-Monooxygenase

Twelve novel dicoumarol glucagon-like peptide 1 (GLP-1) conjugates were designed, synthesized, and tested for biological activity. All derivatives retained receptor activation efficacy, and exhibited improved albumin affinity and in vitro stability in rat plasma. The in vivo elimination half-lives of 13c and 13 l (22.07 and 18.78 h, respectively) were much longer than those of the GLP-1 receptor agonists exendin-4 (2.82 h) and liraglutide (12.53 h). The prolonged in vivo antidiabetic effects of 13c and 13 l on db/db mice were confirmed by the hypoglycemic efficacy test and the multiple intraperitoneal glucose tolerance test. Importantly, a once daily administration of 13c to db/db mice for 7 weeks provided long-term beneficial effects by lowering glycated hemoglobin (HbA1c) levels to 5.05%, which was lower than with liraglutide treatment (5.41%). These results suggest that 13c is a promising long-lasting GLP-1 mimetic that may be suitable for clinical use following further research.

Topics: Animals; Coumarins; Diabetes Mellitus, Experimental; Disease Models, Animal; Drug Design; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Glucose Tolerance Test; Glycated Hemoglobin; Half-Life; HEK293 Cells; Humans; Hypoglycemic Agents; Male; Mice; Mice, Obese; Molecular Structure; Rats; Rats, Sprague-Dawley; Receptors, Glucagon; Serum Albumin

A direct involvement of the antioxidant enzyme NAD(P)H:quinone oxidoreductase (NQO1) in neuroprotection has not yet been shown. The aim of this study was to examine changes, localization and role of NQO1 after different neuronal injury paradigms. In primary cultures of rat cortex the activity of NQO1 was measured after treatment with ethylcholine aziridinium (AF64A; 40 micro m), inducing mainly apoptotic cell death, or oxygen-glucose deprivation (OGD; 120 min), which combines features of apoptotic and necrotic cell death. After treatment with AF64A a significant NQO1 activation started after 24 h. Sixty minutes after OGD a significant early induction of the enzyme was observed, followed by a second increase 24 h later. Enzyme activity was preferentially localized in glial cells in control and injured cultures, however, expression also occurred in injured neuronal cells. Inhibition of the NQO1 activity by dicoumarol, cibacron blue or chrysin (1-100 nM) protected the cells both after exposure to AF64A or OGD as assessed by the decreased release of lactate dehydrogenase. Comparable results were obtained in vivo using a mouse model of focal cerebral ischaemia. Dicoumarol treatment (30 nmol intracerebroventricular) reduced the infarct volume by 29% (p = 0.005) 48 h after the insult. After chemical induction of NQO1 activity by t-butylhydroquinone in vitro neuronal damage was exaggerated. Our data suggest that the activity of NQO1 is a deteriorating rather than a protective factor in neuronal cell death.

Topics: Animals; Apoptosis; Aziridines; Brain Ischemia; Cells, Cultured; Choline; Dicumarol; Disease Models, Animal; Disease Progression; Drug Synergism; Enzyme Activation; Enzyme Inhibitors; Hydroquinones; Male; Mice; Mice, Inbred C57BL; NAD(P)H Dehydrogenase (Quinone); NADPH Dehydrogenase; Neurons; Rats; Rats, Wistar

To detect the role of the enzyme gamma-glutamyl carboxylase in an experimental stone-forming condition.. Urolithiasis was induced in experimental rats by (i) oral feeding of 1% ethylene glycol (EG) and (ii) feeding a calculus-producing diet containing 3% sodium glycolate.. A significant enhancement in the activity of renal vitamin-K-dependent gamma-glutamyl carboxylase was observed in both groups of experimental urolithic rats. Dicoumarol as well as EG treatment enhanced the accumulation of the endogenous substrate for the enzyme. The carboxylase activity was stimulated by sodium oxalate as well as calcium oxalate in vitro. A positive correlation was observed between lipid peroxidation and the renal gamma-glutamyl carboxylase activity.. The enhanced carboxylase activity observed in the hyperoxaluric condition is suggested to be due to stimulation of the enzyme by oxalate/calcium oxalate, increased concentration of endogenous carboxylase substrate and lipid peroxidation.

Topics: Animals; Carbon-Carbon Ligases; Dicumarol; Disease Models, Animal; Enzyme Activation; Ethylene Glycol; Glycolates; In Vitro Techniques; Kidney; Male; Oxalates; Rats; Rats, Wistar; Urinary Calculi

Oral exposure of DBA/2 mice to benzo[a]pyrene (BP) has been shown to result in hematotoxicity which is manifested as aplastic anemia and leukemia. Since normal hematopoiesis is regulated by bone marrow stromal cells, in this study we have characterized the bone marrow stromal toxicity induced by BP and BP-derived metabolites, particularly quinones. Incubation of stromal cells with various concentrations of BP-1,6-, 3,6-, 6,12-, or 7,8-quinone for 24 hr resulted in a significant decrease of cell survival in a concentration-dependent manner, while cells treated with BP or BP-7,8-dihydrodiol did not exhibit any significant loss of cell survival. Among the BP quinones examined, BP-1,6-quinone was the most cytotoxic to stromal cells. The cytotoxicity induced by BP-1,6-quinone also exhibited a time-dependent relationship. Pretreatment of stromal cells with 1,2-dithiole-3-thione (D3T) resulted in a significant induction of both cellular reduced glutathione (GSH) content and quinone reductase (QR) activity in a concentration-dependent manner. However, D3T pretreatment did not offer any protection against BP-1,6-quinone-induced toxicity. Furthermore, dicumarol, a potent inhibitor of QR, or buthionine sulfoximine, a specific inhibitor of GSH biosynthesis, did not potentiate BP-1,6-quinone-induced cytotoxicity was not altered. However, incubation of stromal cells with BP-1,6-quinone resulted in a significant depletion of cellular ATP content and mitochondrial morphological changes, which preceded the loss of cell survival. In addition to BP-1,6-quinone, other cytotoxic BP quinones also exhibited a capacity to deplete cellular ATP level in stromal cells, while BP, which was not cytotoxic to stromal cells, did not elicit any significant decrease in cellular ATP level. These observations suggest that mitochondria may be a potential target of BP quinones. Overall, the above results indicate that neither cellular GSH and QR nor reactive oxygen species appear to be involved in BP quinone-induced stromal cell injury and that BP quinones may elicit cytotoxicity to stromal cells through directly disrupting mitochondrial energy metabolism.

Topics: Adenosine Triphosphate; Anemia, Aplastic; Animals; Antimetabolites, Antineoplastic; Antineoplastic Agents; Benzo(a)pyrene; Benzopyrenes; Bone Marrow; Bone Marrow Cells; Buthionine Sulfoximine; Cell Survival; Cells, Cultured; Dicumarol; Disease Models, Animal; Dose-Response Relationship, Drug; Glutathione; Leukemia, Experimental; Male; Methionine Sulfoximine; Mice; Mice, Inbred DBA; Mitochondria; NAD(P)H Dehydrogenase (Quinone); Quinones; Stromal Cells; Superoxide Dismutase; Thiones; Thiophenes

Veterinarians and physicians are frequently not fully aware of the interdependencies of veterinary and human medicine. This short outline of the history of anticoagulation by dicumarol(analogues) beginning with the observation in 1922 of a previously unknown illness in cattle is intended to point out this important interrelation.

Topics: Animals; Anticoagulants; Canada; Cattle; Cattle Diseases; Dicumarol; Disease Models, Animal; History, 20th Century; Humans; Hypoprothrombinemias; Thromboembolism; United States

Chronic investigations (up to 3 years) conducted in dogs have evidenced that periodic disturbances of vascular permeability produced by using dicoumarin with a long-term blocking of the thyroid function greatly aggravate pathological manifestations induced by the action of 6-methylthiouracil. They result in the development in the animals of endogenous hypercholesterinemia, elevated content in the blood of beta-lipoproteins and in a periodic rise of the arterial pressure. These changes were particularly spectacular at the final stage of the experiment in animals with marked manifestations of atherosclerosis and were accompanied by reduced stand-by potentialities of the adrenal gland, disruption of metabolic processes in the myocardium along with the slowed down resorption of NaI131 from the heart muscle. The sensitivity of the heart to adrenalin was down too.

Topics: 17-Hydroxycorticosteroids; Adrenal Cortex; Animals; Arteriosclerosis; Capillary Permeability; Dicumarol; Disease Models, Animal; Dogs; Lipids; Methylthiouracil

Topics: Animals; Dicumarol; Disease Models, Animal; Hemorrhage; Hemostasis; Heparin; Humans; Rats; Sodium Chloride; Stress, Psychological