5-hydroxy-6-8-11-14-eicosatetraenoic-acid 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

5-lipoxygenase (5-LOX), a member of the lipoxygenase gene family, is a key enzyme assisting in the conversion of arachidonic acid to 5-HETE and leukotrienes. Tumor-associated macrophages (TAMs) have a critical role in the progression and metastasis of many tumors, including ovarian tumors. Moreover, TAMs are often found in a high density in the hypoxic areas of tumors. However, the relevant mechanisms have not been studied explicitly until now. In this study, we found that the expression of 5-LOX strongly correlated with the density of TAMs in hypoxic areas of human ovarian tumor tissues. In cultured ovarian cancer cells, 5-LOX metabolites were increased under hypoxic conditons. Increased 5-LOX metabolites from hypoxic ovarian cancer cells promoted migration and invasion of macrophages, which was further demonstrated to be mediated by the upregulation of matrix metalloproteinase (MMP)-7 expression through the p38 pathway. Besides, we also showed that 5-LOX metabolites enhanced the release of tumor necrosis factor (TNF-α) and heparin-binding epidermal growth factor-like growth factor through upregulation of MMP-7. Furthermore, in animal models, Zileuton (a selective and specific 5-LOX inhibitor) reduced the MMP-7 expression and the number of macrophages infiltrating in the xenograft. Our findings suggest for the first time that increased metabolites of 5-LOX from hypoxic ovarian cancer cells promote TAM infiltration. These results of this study have immediate translational implications for the therapeutic exploitation of TAMs.

Topics: Animals; Arachidonate 5-Lipoxygenase; Cell Line; Cell Line, Tumor; Chemotaxis, Leukocyte; Disease Models, Animal; Female; Heparin-binding EGF-like Growth Factor; Heterografts; Humans; Hydroxyeicosatetraenoic Acids; Hydroxyurea; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Leukotriene B4; Macrophages; MAP Kinase Signaling System; Matrix Metalloproteinase 7; Mice; Neoplasm Metastasis; Ovarian Neoplasms; Tumor Necrosis Factor-alpha

We compared amounts of lipoxygenase products with the extent of leukocyte infiltration in the ischemic myocardium with an occlusion-reperfusion model of open-chest dog. Changes in peripheral leukocyte count and leukocyte function estimated by neutrophil aggregation induced by calcium ionophore A23187 were also examined. The ischemic tissue (120 +/- 40 ng/g, mean +/- SEM) showed a marked increase in 12-hydroxyeicosatetraenoic acid (HETE) production compared with the normal tissue (13 +/- 1 ng/g, p less than 0.01). The production of 5-HETE in the ischemic tissue was also augmented as well. When we examined the correlation between production of either 12-HETE or 5-HETE and leukocyte infiltration in the ischemic tissue, the former was augmented markedly in proportion to the extent of the latter. Leukocyte count in peripheral circulation was gradually increased after reperfusion. Similarly, neutrophil aggregation was significantly augmented during reperfusion. These results indicate that production of lipoxygenase metabolites associated with leukocyte infiltration in the reperfused ischemic tissue was increased during the course of myocardial infarction, which was accompanied by activation of leukocyte in peripheral circulation. Further studies should be done to clarify the importance of lipoxygenase metabolites in the evolution of reperfusion-induced myocardial injury.

Topics: 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; Animals; Cell Aggregation; Chromatography, High Pressure Liquid; Coronary Disease; Disease Models, Animal; Dogs; Hydroxyeicosatetraenoic Acids; Leukocyte Count; Leukocytes; Lipoxygenase; Lymphocyte Activation; Myocardial Infarction; Myocardium; Perfusion