novobiocin and Disease-Models--Animal

Topics: Animals; Anti-Bacterial Agents; Bacteria; Bacterial Infections; Chemical Phenomena; Chemistry; Coumarins; Disease Models, Animal; Dogs; Drug Resistance, Microbial; Humans; Mice; Novobiocin; Rats; Species Specificity; Streptomyces; Structure-Activity Relationship

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

Burkholderia pseudomallei causes melioidosis, a potentially lethal disease that can establish both chronic and acute infections in humans. It is inherently recalcitrant to many antibiotics, there is a paucity of effective treatment options and there is no vaccine. In the present study, the efficacies of selected aminocoumarin compounds, DNA gyrase inhibitors that were discovered in the 1950s but are not in clinical use for the treatment of melioidosis were investigated. Clorobiocin and coumermycin were shown to be particularly effective in treating B. pseudomallei infection in vivo. A novel formulation with dl-tryptophan or l-tyrosine was shown to further enhance aminocoumarin potency in vivo. It was demonstrated that coumermycin has superior pharmacokinetic properties compared with novobiocin, and the coumermycin in l-tyrosine formulation can be used as an effective treatment for acute respiratory melioidosis in a murine model. Repurposing of existing approved antibiotics offers new resources in a challenging era of drug development and antimicrobial resistance.

Topics: Aminocoumarins; Animals; Burkholderia pseudomallei; Disease Models, Animal; Drug Resistance, Multiple, Bacterial; Drug Therapy, Combination; Female; Melioidosis; Mice; Mice, Inbred BALB C; Moths; Novobiocin; Tryptophan

Chemotherapy induced cognitive impairment (i.e. chemobrain) involves acute and long-term deficits in memory, executive function, and processing speed. Animal studies investigating these cognitive deficits have had mixed results, potentially due to variability in the complexity of behavioral tasks across experiments. Further, common chemotherapy treatments such as 5-fluorouracil (5-FU) break down myelin integrity corresponding to hippocampal neurodegenerative deficits and mitochondrial dysfunction. There is little evidence, however, of pharmacological treatments that may target mitochondrial dysfunction. Using a differential reinforcement of low rates (DRL) task combining spatial and temporal components, the current study evaluated the preventative effects of the pharmacological agent KU32 on the behavior of rats treated with 5-FU (5-FU+Saline vs. 5FU+KU32). DRL performance was analyzed the day after the first set of injections (D1), the day after the second set of injections (D7) and the last day of the experiment (D14). The 5FU+KU32 group earned significantly more reinforcers on the DRL task at D7 and D14 than the 5FU+Saline group. Further, the 5FU+KU32 group showed significantly better temporal discrimination. The 5FU+KU32 showed within-group improvement in temporal discrimination from D7 to D14. No significant differences were observed in spatial discrimination, however, those in the 5FU+Saline group responded more frequently on T3 compared to the 5FU+KU32 group, highlighting temporal discrimination differences between groups. The current data suggest that KU32 shows promise in the prevention of chemotherapy induced impairments in temporal discrimination.

Topics: Analysis of Variance; Animals; Cognition Disorders; Disease Models, Animal; Fluorouracil; Immunosuppressive Agents; Neuroprotective Agents; Novobiocin; Rats; Rats, Wistar; Time Factors

The discovery and optimization of a new class of bacterial topoisomerase (DNA gyrase and topoisomerase IV) inhibitors binding in the ATP domain are described. A fragment molecule, 1-ethyl-3-(2-pyridyl)urea, provided sufficiently potent enzyme inhibition (32 μM) to prompt further analogue work. Acids and acid isosteres were incorporated at the 5-pyridyl position of this fragment, bridging to a key asparagine residue, improving enzyme inhibition, and leading to measurable antibacterial activity. A CF3-thiazole substituent at the 4-pyridyl position improved inhibitory potency due to a favorable lipophilic interaction. Promising antibacterial activity was seen versus the Gram-positive pathogens Staphylococcus aureus and Streptococcus pneumoniae and the Gram-negative pathogens Haemophilus influenzae and Moraxella catarrhalis . Precursor metabolite incorporation and mutant analysis studies support the mode-of-action, blockage of DNA synthesis by dual target topoisomerase inhibition. Compound 35 was efficacious in a mouse S. aureus disease model, where a 4.5-log reduction in colony forming units versus control was demonstrated.

Topics: Adenosine Triphosphate; Animals; Anti-Bacterial Agents; Bacteria; Disease Models, Animal; DNA Topoisomerases, Type II; Dose-Response Relationship, Drug; Drug Discovery; Mice; Microbial Sensitivity Tests; Models, Molecular; Molecular Structure; Staphylococcal Infections; Structure-Activity Relationship; Topoisomerase II Inhibitors; Urea

African sleeping sickness, caused by the protozoan parasite Trypanosoma brucei, is universally fatal if untreated, and current drugs are limited by severe toxicities and difficult administration. New antitrypanosomals are greatly needed. Heat shock protein 90 (Hsp90) is a conserved and ubiquitously expressed molecular chaperone essential for stress responses and cellular signaling. We investigated Hsp90 inhibitors for their antitrypanosomal activity. Geldanamycin and radicicol had nanomolar potency in vitro against bloodstream-form T. brucei; novobiocin had micromolar activity. In structure-activity studies of geldanamycin analogs, 17-AAG and 17-DMAG were most selective against T. brucei as compared to mammalian cells. 17-AAG treatment sensitized trypanosomes to heat shock and caused severe morphological abnormalities and cell cycle disruption. Both oral and parenteral 17-DMAG cured mice of a normally lethal infection of T. brucei. These promising results support the use of inhibitors to study Hsp90 function in trypanosomes and to expand current clinical development of Hsp90 inhibitors to include T. brucei.

Topics: Animals; Antiprotozoal Agents; Benzoquinones; Disease Models, Animal; Enzyme Inhibitors; Female; HSP90 Heat-Shock Proteins; Lactams, Macrocyclic; Macrolides; Mice; Novobiocin; Structure-Activity Relationship; Treatment Outcome; Trypanosoma brucei brucei; Trypanosomiasis, African

New classes of drugs are needed to treat tuberculosis (TB) in order to combat the emergence of resistance to existing agents and shorten the duration of therapy. Targeting DNA gyrase is a clinically validated therapeutic approach using fluoroquinolone antibiotics to target the gyrase subunit A (GyrA) of the heterotetramer. Increasing resistance to fluoroquinolones has driven interest in targeting the gyrase subunit B (GyrB), which has not been targeted for TB. The biological activities of two potent small-molecule inhibitors of GyrB have been characterized to validate its targeting as a therapeutic strategy for treating TB.. Novobiocin and aminobenzimidazole 1 (AB-1) were tested for their activity against Mycobacterium tuberculosis (Mtb) H37Rv and other mycobacteria. AB-1 and novobiocin were also evaluated for their interaction with rifampicin and isoniazid as well as their potential for cytotoxicity. Finally, AB-1 was tested for in vivo efficacy in a murine model of TB.. Novobiocin and AB-1 have both been shown to be active against Mtb with MIC values of 4 and 1 mg/L, respectively. Only AB-1 exhibited time-dependent bactericidal activity against drug-susceptible and drug-resistant mycobacteria, including a fluoroquinolone-resistant strain. AB-1 had potent activity in the low oxygen recovery assay model for non-replicating persistent Mtb. Additionally, AB-1 has no interaction with isoniazid and rifampicin, and has no cross-resistance with fluoroquinolones. In a murine model of TB, AB-1 significantly reduced lung cfu counts in a dose-dependent manner.. Aminobenzimidazole inhibitors of GyrB exhibit many of the characteristics required for their consideration as a potential front-line antimycobacterial therapeutic.

Topics: Animals; Antitubercular Agents; Benzimidazoles; Disease Models, Animal; DNA Gyrase; Drug Interactions; Enzyme Inhibitors; Female; Lung; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Novobiocin; Topoisomerase II Inhibitors; Tuberculosis, Pulmonary

KU-32 is a novel, novobiocin-based Hsp90 inhibitor that protects against neuronal glucotoxicity and reverses multiple clinical indices of diabetic peripheral neuropathy in a rodent model. However, any drug with potential for treating diabetic complications must also have no adverse effects on the function of pancreatic islets. Thus, the goal of the current study was to assess the effect of KU-32 on the in vitro viability and function of human islets. Treating human islets with KU-32 for 24 hours showed no toxicity as assessed using the alamarBlue assay. Confocal microscopy confirmed that with a minimum of 2-day exposure, KU-32 improved cellular viability by blocking apoptosis. Functionally, isolated human islets released more glucose-stimulated insulin when preincubated in KU-32. However, diabetic BKS-db/db mice, a model for type 2 diabetes, administered KU-32 for 10 weeks did not show any significant changes in blood glucose and insulin levels, despite having greater insulin staining/beta cell in the pancreas compared to untreated BKS db/db mice. In summary, KU-32 did not harm isolated human islets and may even be protective. However, the effect does not appear significant enough to alter the in vivo metabolic parameters of diabetic mice.

Topics: Adult; Animals; Apoptosis; Blood Glucose; Cell Survival; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Disease Models, Animal; Dose-Response Relationship, Drug; Female; HSP90 Heat-Shock Proteins; Humans; Insulin; Insulin Secretion; Islets of Langerhans; Male; Mice; Microscopy, Confocal; Middle Aged; Neuroprotective Agents; Novobiocin; Time Factors; Tissue Culture Techniques

Topics: Administration, Oral; Administration, Topical; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents; Cell Degranulation; Chromatography, Gel; Disease Models, Animal; Edema; Glucuronidase; Leukotriene B4; Mice; Mice, Inbred BALB C; Neutrophils; Novobiocin; Rabbits; Skin Diseases; Streptomyces

Herpes simplex virus type 1 was reactivated from the trigeminal ganglia of latently infected mice in a quantitative and time-dependent manner. Novobiocin and coumermycin A1 reversibly inhibited the reactivation of herpes simplex virus type 1. They did not inhibit viral replication in permissive cells (CV-1) but did inhibit replication in cells of neuronal origin (C1300) and acutely infected trigeminal ganglia.

Topics: Aminocoumarins; Animals; Anti-Bacterial Agents; Cell Line; Coumarins; Disease Models, Animal; Herpes Simplex; Mice; Novobiocin; Recurrence; Simplexvirus; Trigeminal Ganglion; Trigeminal Nerve; Virus Replication

Staphylococcus aureus is a frequent cause of bovine mastitis worldwide. A model that may predict the efficacy of antimicrobial agents in the treatment of bovine mastitis induced by Staph. aureus was developed in lactating mice. Infection was established by the inoculation of lactating CF1 mice with Staph. aureus into the mammary gland via the teat duct. At the dose of bacteria used, 85-90% of the inoculated, untreated animals developed a nonlethal, acute mastitis within 48 h. Antibiotic treatment was administered subcutaneously or by the intramammary route. Lincosaminide antibiotics including lincomycin, clindamycin, and pirlimycin were evaluated in this system. Other compounds which have been used in therapy of bovine mastitis including novobiocin, penicillin G, ampicillin, cloxacillin and rifamycin-SV were used as reference antibiotics. Pirlimycin was the most effective of the antibiotics tested in this standardized system. Depending upon the route of administration, this novel lincosaminide was 15 to 95-fold more effective than clindamycin, three- to six-fold better than lincomycin, two- to ten-fold more effective than novobiocin, 13- to 17-times more effective than cloxacillin and 8- to 22-times better than rifamycin-SV on a weight-dose comparison. Penicillin G and ampicillin were the least effective drugs tested against mastitis induced by the beta-lactamase producing strain of Staph. aureus used in these assays. Pharmacokinetic experiments suggested that the greater effectiveness of pirlimycin compared to clindamycin and lincomycin was due to increased affinity for and prolonged retention in the mammary gland.

Topics: Animals; Anti-Bacterial Agents; Cattle; Clindamycin; Cloxacillin; Disease Models, Animal; Female; Injections; Injections, Subcutaneous; Kinetics; Lactation; Lincomycin; Lincosamides; Macrolides; Mammary Glands, Animal; Mastitis; Mastitis, Bovine; Mice; Microbial Sensitivity Tests; Novobiocin; Pregnancy; Rifamycins; Staphylococcal Infections