bafilomycin-a1 and Hemorrhagic-Fever--Ebola

Ebola virus (EBOV) causes a deadly hemorrhagic fever in humans and non-human primates. There is currently no FDA-approved vaccine or medication to counter this disease. Here, we report on the design, synthesis and anti-viral activities of two classes of compounds which show high potency against EBOV in both in vitro cell culture assays and in vivo mouse models Ebola viral disease. These compounds incorporate the structural features of cationic amphiphilic drugs (CAD), i.e they possess both a hydrophobic domain and a hydrophilic domain consisting of an ionizable amine functional group. These structural features enable easily diffusion into cells but once inside an acidic compartment their amine groups became protonated, ionized and remain trapped inside the acidic compartments such as late endosomes and lysosomes. These compounds, by virtue of their lysomotrophic functions, blocked EBOV entry. However, unlike other drugs containing a CAD moiety including chloroquine and amodiaquine, compounds reported in this study display faster kinetics of accumulation in the lysosomes, robust expansion of late endosome/lysosomes, relatively more potent suppression of lysosome fusion with other vesicular compartments and inhibition of cathepsins activities, all of which play a vital role in anti-EBOV activity. Furthermore, the diazachrysene 2 (ZSML08) that showed most potent activity against EBOV in in vitro cell culture assays also showed significant survival benefit with 100% protection in mouse models of Ebola virus disease, at a low dose of 10 mg/kg/day. Lastly, toxicity studies in vivo using zebrafish models suggest no developmental defects or toxicity associated with these compounds. Overall, these studies describe two new pharmacophores that by virtue of being potent lysosomotrophs, display potent anti-EBOV activities both in vitro and in vivo animal models of EBOV disease.

Topics: Animals; Antiviral Agents; Chrysenes; Ebolavirus; Hemorrhagic Fever, Ebola; Lysosomes; Mice; Surface-Active Agents; Virus Internalization; Zebrafish

Filoviruses, consisting of Ebola virus (EBOV) and Marburg virus (MARV), are among the most lethal infectious threats to mankind. Infections by these viruses can cause severe hemorrhagic fevers in humans and nonhuman primates with high mortality rates. Since there is currently no vaccine or antiviral therapy approved for humans, there is an urgent need to develop prophylactic and therapeutic options for use during filoviral outbreaks and bioterrorist attacks. One of the ideal targets against filoviral infection and diseases is at the entry step, which is mediated by the filoviral glycoprotein (GP). In this report, we screened a chemical library of small molecules and identified numerous inhibitors, which are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs, including histamine receptors, 5-HT (serotonin) receptors, muscarinic acetylcholine receptor, and adrenergic receptor. These inhibitors can effectively block replication of both infectious EBOV and MARV, indicating a broad antiviral activity of the GPCR antagonists. The time-of-addition experiment and microscopic studies suggest that GPCR antagonists block filoviral entry at a step following the initial attachment but prior to viral/cell membrane fusion. These results strongly suggest that GPCRs play a critical role in filoviral entry and GPCR antagonists can be developed as an effective anti-EBOV/MARV therapy.. Infection of Ebola virus and Marburg virus can cause severe illness in humans with a high mortality rate, and currently there is no FDA-approved vaccine or therapeutic treatment available. The 2013-2015 epidemic in West Africa underscores a lack of our understanding in the infection and pathogenesis of these viruses and the urgency of drug discovery and development. In this study, we have identified numerous inhibitors that are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs. These inhibitors can effectively block replication of both infectious EBOV and MARV, indicating a broad antiviral activity of the GPCR antagonists. Our results strongly suggest that GPCRs play a critical role in filoviral entry and GPCR antagonists can be developed as an effective anti-EBOV/MARV therapy.

Topics: Animals; Antiviral Agents; Benztropine; Cell Line; Chlorocebus aethiops; Cyproheptadine; Ebolavirus; HEK293 Cells; Hemorrhagic Fever, Ebola; Heparin; High-Throughput Screening Assays; Humans; Macrolides; Marburg Virus Disease; Marburgvirus; Receptors, G-Protein-Coupled; Small Molecule Libraries; Vero Cells; Virus Internalization; Zidovudine