Biology subjects

Hage, A.

Publications and source records attributed to Hage, A..

3 recordsLinked to original sources

bioRxiv2020

Topoisomerase III-beta is required for efficient replication of positive-sense RNA viruses

Based on genome-scale loss-of-function screens we discovered that Topoisomerase III-{beta} (TOP3B), a human topoisomerase that acts on DNA and RNA, is required for yellow fever virus and dengue virus-2 replication. Remarkably, we found that TOP3B is required for efficient replication of all positive-sense-single stranded RNA viruses tested, including SARS-CoV-2. While there are no drugs that specifically inhibit this topoisomerase, we posit that TOP3B is an attractive anti-viral target.

microbiology↗

bioRxiv2019

VAMP8 contributes to TRIM6-mediated type-I interferon antiviral response during West Nile virus infection

Several members of the tripartite motif (TRIM) family of E3 ubiquitin ligases regulate immune pathways including the antiviral type I interferon (IFN-I) system. Previously, we demonstrated that TRIM6 is involved in IFN-I induction and signaling. In the absence of TRIM6, optimal IFN-I signaling is reduced, allowing increased replication of interferon-sensitive viruses. Despite having evolved numerous mechanisms to restrict the vertebrate hosts IFN-I response, West Nile Virus (WNV) replication is sensitive to pre-treatment with IFN-I. However, the regulators and products of the IFN-I pathway that are important in regulating WNV replication are incompletely defined. Consistent with WNVs sensitivity to IFN-I, we found that in TRIM6 knockout (TRIM6-KO) A549 cells WNV replication is significantly increased and IFN-I induction and signaling is impaired compared to wild-type (wt) cells. IFN{beta} pre-treatment was more effective in protecting against subsequent WNV infection in wt cells as compared to TRIM6-KO, indicating that TRIM6 contributes to the establishment of an IFN-induced antiviral response against WNV. Using next generation sequencing, we identified VAMP8 as a potential factor involved in this TRIM6-mediated antiviral response. VAMP8 knockdown resulted in reduced Jak1 and STAT1 phosphorylation and impaired induction of several ISGs following WNV infection or IFN{beta} treatment. Furthermore, VAMP8-mediated STAT1 phosphorylation required the presence of TRIM6. Therefore, the VAMP8 protein is a novel regulator of IFN-I signaling, and its expression and function is dependent on TRIM6 activity. Overall, these results provide evidence that TRIM6 contributes to the antiviral response against WNV and identified VAMP8 as a novel regulator of the IFN-I system.\n\nIMPORTANCEWNV is a mosquito-borne flavivirus that poses threat to human health across large discontinuous areas throughout the world. Infection with WNV results in febrile illness, which can progress to severe neurological disease. Currently, there are no approved treatment options to control WNV infection. Understanding the cellular immune responses that regulate viral replication is important in diversifying the resources available to control WNV. Here we show that the elimination of TRIM6 in human cells results in an increase in WNV replication and alters the expression and function of other components of the IFN-I pathway through VAMP8. Dissecting the interactions between WNV and host defenses both informs basic molecular virology and promotes the development of host- and viral-targeted antiviral strategies.

immunology↗

bioRxiv2019

Peptidoglycan associated cyclic lipopeptide disrupts viral infectivity

Enteric viruses exploit bacterial components including lipopolysaccharides (LPS) and peptidoglycan (PG) to facilitate infection in humans. With origins in the bat enteric system, we wondered if severe acute respiratory syndrome-coronavirus (SARS-CoV) or Middle East respiratory syndrome-CoV (MERS-CoV) also use bacterial components to modulate infectivity. To test this question, we incubated CoVs with LPS and PG and evaluated infectivity finding no change following LPS treatment. However, PG from B. subtilis reduced infection >10,000-fold while PG from other bacterial species failed to recapitulate this. Treatment with an alcohol solvent transferred inhibitory activity to the wash and mass spectrometry revealed surfactin, a cyclic lipopeptide antibiotic, as the inhibitory compound. This antibiotic had robust dose- and temperature-dependent inhibition of CoV infectivity. Mechanistic studies indicated that surfactin disrupts CoV virion integrity and surfactin treatment of the virus inoculum ablated infection in vivo. Finally, similar cyclic lipopeptides had no effect on CoV infectivity and the inhibitory effect of surfactin extended broadly to enveloped viruses including influenza, Ebola, Zika, Nipah, Chikungunya, Una, Mayaro, Dugbe, and Crimean-Congo hemorrhagic fever viruses. Overall, our results indicate that peptidoglycan-associated surfactin has broad virucidal activity and suggest bacteria byproducts may negatively modulate virus infection.\n\nImportanceIn this manuscript, we considered a role for bacteria in shaping coronavirus infection. Taking cues from studies of enteric viruses, we initially investigated how bacterial surface components might improve CoV infection. Instead, we found that peptidoglycan-associated surfactin is a potent viricidal compound that disrupts virion integrity with broad activity against enveloped viruses. Our results indicate that interactions with commensal bacterial may improve or disrupt viral infections highlighting the importance of understanding these microbial interactions and their implications for viral pathogenesis and treatment.

microbiology↗