Observations are consistent with CQ arresting GW 501516 endosomal PF-3084014 supplier trafficking from the early to late endosome, which causes accumulation of virus that does not progress to the late endosome as normal, resulting in an abortive infection. Our screening data and many in vitro studies have suggested that CQ inhibits a number of viral pathogens through nonspecific effects on cell entry events. The generally accepted mechanism is that CQ is a lysosomatropic agent that accumulates in endosomal compartments, where it interferes with acidification, alters vesicle sorting, and inhibits the events that trigger fusion and release of viral components into the cytosol. In the case of EBOV, the mechanism of CQ appears in part to be due to its wellcharacterized inhibitory effects on the pH-dependent cathepsins B and L, which have been shown to play essential and accessory roles, respectively, in EBOV GP processing events prior to fusion. Our data further show that at the concentration tested, CQ directly perturbs virus trafficking, leading to the formation of what appear to be aggregates of accumulated virus particles. In this case, CQ appears to inhibit progression of EBOV through the cell, in addition to potential effects on proteolytic processing. It is currently unclear which mechanism is most important for the observed effects of CQ in vitro and in vivo. In addition to its impact on viral trafficking, CQ has been shown to interfere with viral replication by impairing the glycosylation machinery in the Golgi that would direct trafficking and maturation of nascent viral proteins. This is thought to be the major mechanism by which CQ inhibits HIV and may also affect filoviruses and influenza, which are dependent on glycosylation for both cell attachment and uptake. CQ has also been demonstrated to inhibit endocytic toll-like receptor signaling, which may have in vivo effects on key innate responses that depend on endosomal recognition of pathogen nucleic acids or other components. A large body of evidence implicates CQ in the inhibition of the entry processes of diverse viral families and suggests that this may be a valid approach to repurpose an inexpensive, widely available drug as a much-needed countermeasure in either a mono- or combination therapy. Our results provide further
