Anti-Human Rhinovirus 1B Activity of Dexamethasone viaGCR-Dependent Autophagy Activation

OBJECTIVES: Human rhinoviruses (HRVs) are the major cause of the common cold. Currently there is no registered, clinically effective, antiviral chemotherapeutic agent to treat diseases caused by HRVs. In this study, the antiviral activity of dexamethasone (DEX) against HRV1B was examined. METHODS: The anti–HRV1B activity of DEX was assessed by sulforhodamine B assay in HeLa cells, and by RT-PCR in the lungs of HRV1B-infected mice. Histological evaluation of HRV1B-infected lungs was performed and a histological score was given. Anti-HRV1B activity of DEX via the glucocorticoid receptor (GCR)-dependent autophagy activation was assessed by blocking with chloroquine diphosphate salt or bafilomycin A1 treatment. RESULTS: In HRV1B-infected HeLa cells, treatment with DEX in a dose-dependent manner, resulted in a cell viability of > 70% indicating that HRV1B viral replication was reduced by DEX treatment. HRV1B infected mice treated with DEX, had evidence of reduced inflammation and a moderate histological score. DEX treatment showed antiviral activity against HRV1B via GCR-dependent autophagy activation. CONCLUSION: This study demonstrated that DEX treatment showed anti-HRV1B activity via GCR-dependent autophagy activation in HeLa cells and HRV1B infected mice. Further investigation assessing the development of topical formulations may enable the development of improved DEX effectiveness.

Antiviral Activity of Itraconazole against Echovirus 30 Infection In Vitro

OBJECTIVES: Echovirus 30 is a major cause of meningitis in children and adults. The aim of this study was to investigate whether the antifungal drug itraconazole could exhibit antiviral activity against echovirus 30. METHODS: The cytopathic effect and viral RNA levels were assessed in RD cells as indicators of viral replication. The effects of itraconazole were compared to those of two known antiviral drugs, rupintrivir and pleconaril. The time course and time-of-addition assays were used to approximate the time at which itraconazole exerts its activity in the viral cycle. RESULTS: Itraconazole and rupintrivir demonstrated the greatest potency against echovirus 30, demonstrating concentration-dependent activity, whereas pleconaril showed no antiviral activity. Itraconazole did not directly inactivate echovirus 30 particles or impede viral uptake into RD cells, but did affect the initial stages of echovirus 30 infection through interference with viral replication. CONCLUSION: Itraconazole can be considered a lead candidate for the development of antiviral drugs against echovirus 30 that may be used during the early stages of echovirus 30 replication.

Inhibitory Effects of Norwogonin, Oroxylin A, and Mosloflavone on Enterovirus 71

Severe complications associated with EV71 infections are a common cause of neonatal death. Lack of effective therapeutic agents for these infections underlines the importance of research for the development of new antiviral compounds. In the present study, the anti-EV71 activity of norwogonin, oroxylin A, and mosloflavone from Scutellaria baicalensis Georgi was evaluated using a cytopathic effect (CPE) reduction method, which demonstrated that all three compounds possessed strong anti-EV71 activity and decreased the formation of visible CPEs. Norwogonin, oroxylin A, and mosloflavone also inhibited virus replication during the initial stage of virus infection, and they inhibited viral VP2 protein expression, thereby inhibiting viral capsid protein synthesis. However, ribavirin has a relatively weaker efficacy compared to the other drugs. Therefore, these findings provide important information that will aid in the utilization of norwogonin, oroxylin A, and mosloflavone for EV71 treatment.