A Diacylglycerol Kinase Inhibitor, R-59-022, Blocks Filovirus Internalization in Host Cells.

Filoviruses, such as Ebola virus (EBOV) and Marburg virus, are causative agents of unpredictable outbreaks of severe hemorrhagic fevers in humans and non-human primates. For infection, filoviral particles need to be internalized and delivered to intracellular vesicles containing cathepsin proteases and the viral receptor Niemann-Pick C1. Previous studies have shown that EBOV triggers macropinocytosis of the viral particles in a glycoprotein (GP)-dependent manner, but the molecular events required for filovirus internalization remain mostly unknown. Here we report that the diacylglycerol kinase inhibitor, R-59-022, blocks EBOV GP-mediated entry into Vero cells and bone marrow-derived macrophages. Investigation of the mode of action of the inhibitor revealed that it blocked an early step in entry, more specifically, the internalization of the viral particles via macropinocytosis. Finally, R-59-022 blocked viral entry mediated by a panel of pathogenic filovirus GPs and inhibited growth of replicative Ebola virus. Taken together, our studies suggest that R-59-022 could be used as a tool to investigate macropinocytic uptake of filoviruses and could be a starting point for the development of pan-filoviral therapeutics.

Non-nutritive swallowing and respiration coordination among states of alertness in adult sheep.

Swallowing is a powerful inhibitor of respiration. Its coordination with respiration is therefore crucial to avoid aspiration and apnea. The aim of this study was to determine the coordination between non-nutritive swallowing (NNS) and phases of the respiratory cycle, including the assessment of the effect of states of alertness in adult sheep. Six animals were surgically instrumented under general anesthesia to record electroencephalography, electro-oculography (state of alertness), diaphragmatic electromyography (EMG), nasal flow (respiration), esophageal EMG, and the thyroarytenoid muscle (NNS). Our results revealed that (1) the highest NNS frequency is observed in rapid eye movement (REM) sleep, especially for bursts of NNS; (2) while NNS begins mainly during inspiration in all states of alertness, REM sleep, however, is responsible for an increase in the proportion of NNS beginning in expiration; (3) the link between inspiration and NNS is not affected by rumination. In conclusion, the link between NNS and inspiration in adult sheep is similar to that of lambs but contrary to previous reports on NNS induced by water in humans. Whether these differences are related to interspecies differences or the experimental techniques clearly needs further studies on spontaneous NNS in humans.