Small-Molecule Inhibitors of Dengue-Virus Entry

Flavivirus envelope protein (E) mediates membrane fusion and viral entry from endosomes. A low-pH induced, dimer-to-trimer rearrangement and reconfiguration of the membrane-proximal “stem" of the E ectodomain draw together the viral and cellular membranes. We found stem-derived peptides from dengue virus (DV) bind stem-less E trimer and mimic the stem-reconfiguration step in the fusion pathway. We adapted this experiment as a high-throughput screen for small molecules that block peptide binding and thus may inhibit viral entry. A compound identified in this screen, 1662G07, and a number of its analogs reversibly inhibit DV infectivity. They do so by binding the prefusion, dimeric E on the virion surface, before adsorption to a cell. They also block viral fusion with liposomes. Structure-activity relationship studies have led to analogs with submicromolar IC90s against DV2, and certain analogs are active against DV serotypes 1,2, and 4. The compounds do not inhibit the closely related Kunjin virus. We propose that they bind in a previously identified, E-protein pocket, exposed on the virion surface and although this pocket is closed in the postfusion trimer, its mouth is fully accessible. Examination of the E-trimer coordinates (PDB 1OK8) shows that conformational fluctuations around the hinge could open the pocket without dissociating the trimer or otherwise generating molecular collisions. We propose that compounds such as 1662G07 trap the sE trimer in a “pocket-open" state, which has lost affinity for the stem peptide and cannot support the final “zipping up" of the stem

Endovascular and Medical Management of Cerebral Venous Thrombosis: A Systematic Review and Network Meta-Analysis

OBJECTIVE: Management of cerebral venous thrombosis (CVT) involves minimizing expansion of the thrombus and promoting the recanalization of the venous sinus. While current guidelines include indications of endovascular management and anticoagulation with heparin and warfarin, the use of direct-acting oral anticoagulants (DOACs) has increased. In this study, we aim to conduct a network meta-analysis comparing these 3 therapeutic options: standard anticoagulation, DOACs, and endovascular treatments (EVTs). METHODS: Seventeen of 2265 studies identified from 4 publication databases met inclusion criteria for this network meta-analysis. Outcomes analyzed included modified Rankin Scale score, complications, mortality, and 6-month recanalization rates using a frequentist network meta-analysis approach. For each outcome, the preferential order of each intervention was ranked hierarchically based on P-score calculations used for frequentist network meta-analyses. RESULTS: Modified Rankin Scale outcomes were not significantly different based on the type of treatment modality (i.e., standard anticoagulation, DOACs, or EVT). Evaluation of complications demonstrated that patients treated with EVT were significantly more likely to experience a worse outcome than individuals treated with standard anticoagulation (odds ratio [OR] = 1.83, P = 0.04). Other comparisons did not demonstrate a significant difference in adverse events. For all-cause mortality outcomes, EVT demonstrated significantly greater odds of mortality than standard anticoagulation (OR = 1.89, P = 0.02). Mortality between DOACs and standard anticoagulation was not significantly different. When comparing 6-month recanalization rates, DOACs and EVT were significantly more effective than standard anticoagulation (OR = 1.93, OR = 2.2, P \u3c 0.05). EVT followed by DOACs was preferred over standard anticoagulation for 6-month recanalization rates. CONCLUSIONS: This network meta-analysis evaluates the outcomes in CVT treatment, comparing standard anticoagulation, DOACs, and EVT, with evidence that DOACs have similar outcomes to standard anticoagulation in the treatment of CVT. EVT resulted in an increased risk of overall mortality but improved 6-month recanalization rates