l-783281 and Disease-Models--Animal

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

Insulin elicits diverse biological responses in many tissues and cell types by binding to its specific receptor. The insulin receptor (IR) is a tetramer consisting of two extracellular alpha subunits and two membrane-spanning beta subunits. The binding of insulin to the receptor causes conformational changes that lead to autophosphorylation and activation of the tyrosine kinase intrinsic to the beta subunits. Insulin receptor transphosphorylates several immediate substrates, resulting in modulation of a cascade of downstream signal transduction molecules. In order to discover small molecules that activate the human insulin receptor tyrosine kinase (IRTK), a cell-based assay was established and utilized to screen a collection of synthetic chemicals and natural product extracts. This effort led to the identification of a nonpeptidyl, small molecule, insulin-mimetic compound (demethylasterriquinone B-1, DMAQ-B1) that was isolated from a mixture of metabolites produced by a tropical endophytic fungus, Pseudomassaria sp. This compound induced human IRTK activation and increased tyrosine phosphorylation of IR beta subunit. It mediated insulin-like effects, including insulin receptor substrate-1 (IRS-1) phosphorylation and activation of phosphotidylinositide 3-kinase and Akt kinase. DMAQ-B1 also exhibited an insulin-like effect on glucose uptake in adipocytes and skeletal muscle tissue. Furthermore, the compound was relatively selective for IR vs. insulin-like growth factor-I (IGF-I) receptor and other homologous receptor tyrosine kinases. In addition, it activated partially purified native IR or recombinant IR kinase, demonstrating the direct interaction of the small molecule with the IR. Oral administration of DMAQ-B1 resulted in significant glucose lowering in two mouse models of diabetes. Thus, DMAQ-B1 represents the first orally active insulin-mimetic agent. Pharmaceutical intervention aimed at augmenting IR function ultimately may prove beneficial as a novel therapeutic option in patients with diabetes.

Topics: Adipocytes; Animals; Arabidopsis Proteins; Ascomycota; CHO Cells; Chromatography, High Pressure Liquid; Cricetinae; Diabetes Mellitus; Diabetes Mellitus, Experimental; Disease Models, Animal; Dose-Response Relationship, Drug; Enzyme Activation; Glucose; Humans; Indoles; Insulin; Kinetics; Mice; Models, Chemical; Muscle, Skeletal; Phosphatidylinositol 3-Kinases; Phosphorylation; Plant Proteins; Potassium Channels; Protein Binding; Protein Conformation; Protein-Tyrosine Kinases; Quinones; Receptor, IGF Type 1; Receptor, Insulin; Recombinant Proteins; Signal Transduction; Substrate Specificity