{"id":{"repo_id":"utmb","oai_identifier":"oai:utmb-ir.tdl.org:2152.3/12686"},"canonical_url":"https://search.dev.ndltd.org/etd/utmb/oai:utmb-ir.tdl.org:2152.3/12686","repository":{"repo_id":"utmb","name":"University of Texas Medical Branch","base_url":"https://utmb-ir.tdl.org/server/oai/request"},"display":{"title":"NEW INSIGHTS INTO THE MOLECULAR PATHOGENESIS OF SEVERE FEVER WITH THROMBOCYTOPENIA SYNDROME VIRUS","abstract":"Severe Fever with Thrombocytopenia Syndrome (SFTS) virus (also known as Dabie Bandavirus) is an emergent tick-borne Phlebovirus isolated from patients presenting with hemorrhagic manifestations. Case fatality rates range from 12-50%, and over 1 billion people live in regions where the virus is endemic. SFTS virus pathogenesis remains understudied despite it being listed as a Category C priority pathogen by NIAID and considered a priority pathogen by the World Health Organization. Understanding mechanisms by which SFTS virus causes severe disease is a necessity for the logical design of therapeutic countermeasures. Though multiple molecular mechanisms of SFTS virus pathogenesis have been uncovered, significant gaps in our understanding of this disease remain. In this work, we set out to dissect the interplay of the Ubiquitin Proteasome System (UPS) and SFTS virus to determine how this virus employs the UPS in its replication cycle. Preliminary data from our laboratory suggest that ubiquitination of the pathogen recognition receptor RIG-I is essential to its interaction with the viral virulence factor NSs (unpublished). Though degradation of RIG-I and other signaling components, including TBK-1, was hypothesized, we found minimal change in the total protein levels of these host factors. However, in the presence of proteasomal inhibitors, an abrogation in the formation of virally induced vesicles was observed. This abrogation resulted in the previously sequestered signaling components, RIG-I and TBK-1, returning to their canonical localization. Despite achieving normal localization of these signaling factors, recovery of interferon production is not observed. Although interferon expression is not observed, several other inflammatory cytokines, including IL-6, RANTES, MIP-1, and G-CSF are observed altered. Additionally, significant inhibition of viral replication is observed during proteasomal inhibitor treatment. In addition to investigating the roles of the UPS in SFTS virus, we also set out to identify and map host pathogen interactions that govern SFTS virus. We employed a novel workflow utilizing in-situ crosslinking coupled with mass spectrometry to develop a high-containment compatible system capable of capturing host: pathogen interactions in-situ. Employing this workflow on SFTS virus infected HuH7 cells, we were able to capture 15 interactors of various viral proteins as well as a wealth of structural data regarding the nucleoprotein. Interactions captured between NSs, and eukaryotic Elongation Factor 1 Alpha (eEF1a) suggest a role of this host factor in the SFTS virus lifecycle. Subcellular localization of eEF1a in the context of SFTS virus infection showed high levels of colocalization. Treatment of infected cells with the eEF1a inhibitors Didemnin B and Ternatin showed potent, nanomolar inhibition of viral replication. Most interestingly, these inhibitors appear to inhibit SFTS virus replication at concentrations below those needed to impair protein synthesis. Differential activation of Caspase 3/7 by these inhibitors suggests a mechanism involving cell survival and apoptosis. Collectively, this work addresses multiple questions regarding the UPS in SFTS virus infection while garnering new ones. This work also sets a precedent for the use of crosslinking mass spectrometry as a tool for the study of high-containment pathogens and implicates eEF1a as an essential host factor for SFTS virus infection.","abstract_html":"Severe Fever with Thrombocytopenia Syndrome (SFTS) virus (also known as Dabie Bandavirus) is an emergent tick-borne Phlebovirus isolated from patients presenting with hemorrhagic manifestations. Case fatality rates range from 12-50%, and over 1 billion people live in regions where the virus is endemic. SFTS virus pathogenesis remains understudied despite it being listed as a Category C priority pathogen by NIAID and considered a priority pathogen by the World Health Organization. Understanding mechanisms by which SFTS virus causes severe disease is a necessity for the logical design of therapeutic countermeasures. Though multiple molecular mechanisms of SFTS virus pathogenesis have been uncovered, significant gaps in our understanding of this disease remain. In this work, we set out to dissect the interplay of the Ubiquitin Proteasome System (UPS) and SFTS virus to determine how this virus employs the UPS in its replication cycle. Preliminary data from our laboratory suggest that ubiquitination of the pathogen recognition receptor RIG-I is essential to its interaction with the viral virulence factor NSs (unpublished). Though degradation of RIG-I and other signaling components, including TBK-1, was hypothesized, we found minimal change in the total protein levels of these host factors. However, in the presence of proteasomal inhibitors, an abrogation in the formation of virally induced vesicles was observed. This abrogation resulted in the previously sequestered signaling components, RIG-I and TBK-1, returning to their canonical localization. Despite achieving normal localization of these signaling factors, recovery of interferon production is not observed. Although interferon expression is not observed, several other inflammatory cytokines, including IL-6, RANTES, MIP-1, and G-CSF are observed altered. Additionally, significant inhibition of viral replication is observed during proteasomal inhibitor treatment. In addition to investigating the roles of the UPS in SFTS virus, we also set out to identify and map host pathogen interactions that govern SFTS virus. We employed a novel workflow utilizing in-situ crosslinking coupled with mass spectrometry to develop a high-containment compatible system capable of capturing host: pathogen interactions in-situ. Employing this workflow on SFTS virus infected HuH7 cells, we were able to capture 15 interactors of various viral proteins as well as a wealth of structural data regarding the nucleoprotein. Interactions captured between NSs, and eukaryotic Elongation Factor 1 Alpha (eEF1a) suggest a role of this host factor in the SFTS virus lifecycle. Subcellular localization of eEF1a in the context of SFTS virus infection showed high levels of colocalization. Treatment of infected cells with the eEF1a inhibitors Didemnin B and Ternatin showed potent, nanomolar inhibition of viral replication. Most interestingly, these inhibitors appear to inhibit SFTS virus replication at concentrations below those needed to impair protein synthesis. Differential activation of Caspase 3/7 by these inhibitors suggests a mechanism involving cell survival and apoptosis. Collectively, this work addresses multiple questions regarding the UPS in SFTS virus infection while garnering new ones. This work also sets a precedent for the use of crosslinking mass spectrometry as a tool for the study of high-containment pathogens and implicates eEF1a as an essential host factor for SFTS virus infection.","abstract_has_math":false,"creators":["Bopp, Nathen"],"institution":"The University of Texas Medical Branch at Galveston","degree_name":"Experimental Pathology (Doctoral)","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-05","date_published":"2022-05","updated_at":"2026-07-24T05:51:01Z","subjects":["Biology, Virology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2152.3/12686","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Bopp, Nathen"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-05-29T12:52:55Z"]},{"key":"dc:date.issued","label":"Date","values":["2022-05"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Experimental Pathology (Doctoral)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["The University of Texas Medical Branch at Galveston"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Biology, Virology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/2152.3/12686"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Severe Fever with Thrombocytopenia Syndrome (SFTS) virus (also known as Dabie Bandavirus) is an emergent tick-borne Phlebovirus isolated from patients presenting with hemorrhagic manifestations. Case fatality rates range from 12-50%, and over 1 billion people live in regions where the virus is endemic. SFTS virus pathogenesis remains understudied despite it being listed as a Category C priority pathogen by NIAID and considered a priority pathogen by the World Health Organization. Understanding mechanisms by which SFTS virus causes severe disease is a necessity for the logical design of therapeutic countermeasures. Though multiple molecular mechanisms of SFTS virus pathogenesis have been uncovered, significant gaps in our understanding of this disease remain. In this work, we set out to dissect the interplay of the Ubiquitin Proteasome System (UPS) and SFTS virus to determine how this virus employs the UPS in its replication cycle. Preliminary data from our laboratory suggest that ubiquitination of the pathogen recognition receptor RIG-I is essential to its interaction with the viral virulence factor NSs (unpublished). Though degradation of RIG-I and other signaling components, including TBK-1, was hypothesized, we found minimal change in the total protein levels of these host factors. However, in the presence of proteasomal inhibitors, an abrogation in the formation of virally induced vesicles was observed. This abrogation resulted in the previously sequestered signaling components, RIG-I and TBK-1, returning to their canonical localization. Despite achieving normal localization of these signaling factors, recovery of interferon production is not observed. Although interferon expression is not observed, several other inflammatory cytokines, including IL-6, RANTES, MIP-1, and G-CSF are observed altered. Additionally, significant inhibition of viral replication is observed during proteasomal inhibitor treatment. In addition to investigating the roles of the UPS in SFTS virus, we also set out to identify and map host pathogen interactions that govern SFTS virus. We employed a novel workflow utilizing in-situ crosslinking coupled with mass spectrometry to develop a high-containment compatible system capable of capturing host: pathogen interactions in-situ. Employing this workflow on SFTS virus infected HuH7 cells, we were able to capture 15 interactors of various viral proteins as well as a wealth of structural data regarding the nucleoprotein. Interactions captured between NSs, and eukaryotic Elongation Factor 1 Alpha (eEF1a) suggest a role of this host factor in the SFTS virus lifecycle. Subcellular localization of eEF1a in the context of SFTS virus infection showed high levels of colocalization. Treatment of infected cells with the eEF1a inhibitors Didemnin B and Ternatin showed potent, nanomolar inhibition of viral replication. Most interestingly, these inhibitors appear to inhibit SFTS virus replication at concentrations below those needed to impair protein synthesis. Differential activation of Caspase 3/7 by these inhibitors suggests a mechanism involving cell survival and apoptosis. Collectively, this work addresses multiple questions regarding the UPS in SFTS virus infection while garnering new ones. This work also sets a precedent for the use of crosslinking mass spectrometry as a tool for the study of high-containment pathogens and implicates eEF1a as an essential host factor for SFTS virus infection."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["NEW INSIGHTS INTO THE MOLECULAR PATHOGENESIS OF SEVERE FEVER WITH THROMBOCYTOPENIA SYNDROME VIRUS"]}]}],"canonical_facts":{"dc:creator":["Bopp, Nathen"],"dc:date.accessioned":["2025-05-29T12:52:55Z"],"dc:date.issued":["2022-05"],"dc:description.abstract":["Severe Fever with Thrombocytopenia Syndrome (SFTS) virus (also known as Dabie Bandavirus) is an emergent tick-borne Phlebovirus isolated from patients presenting with hemorrhagic manifestations. Case fatality rates range from 12-50%, and over 1 billion people live in regions where the virus is endemic. SFTS virus pathogenesis remains understudied despite it being listed as a Category C priority pathogen by NIAID and considered a priority pathogen by the World Health Organization. Understanding mechanisms by which SFTS virus causes severe disease is a necessity for the logical design of therapeutic countermeasures. Though multiple molecular mechanisms of SFTS virus pathogenesis have been uncovered, significant gaps in our understanding of this disease remain. In this work, we set out to dissect the interplay of the Ubiquitin Proteasome System (UPS) and SFTS virus to determine how this virus employs the UPS in its replication cycle. Preliminary data from our laboratory suggest that ubiquitination of the pathogen recognition receptor RIG-I is essential to its interaction with the viral virulence factor NSs (unpublished). Though degradation of RIG-I and other signaling components, including TBK-1, was hypothesized, we found minimal change in the total protein levels of these host factors. However, in the presence of proteasomal inhibitors, an abrogation in the formation of virally induced vesicles was observed. This abrogation resulted in the previously sequestered signaling components, RIG-I and TBK-1, returning to their canonical localization. Despite achieving normal localization of these signaling factors, recovery of interferon production is not observed. Although interferon expression is not observed, several other inflammatory cytokines, including IL-6, RANTES, MIP-1, and G-CSF are observed altered. Additionally, significant inhibition of viral replication is observed during proteasomal inhibitor treatment. In addition to investigating the roles of the UPS in SFTS virus, we also set out to identify and map host pathogen interactions that govern SFTS virus. We employed a novel workflow utilizing in-situ crosslinking coupled with mass spectrometry to develop a high-containment compatible system capable of capturing host: pathogen interactions in-situ. Employing this workflow on SFTS virus infected HuH7 cells, we were able to capture 15 interactors of various viral proteins as well as a wealth of structural data regarding the nucleoprotein. Interactions captured between NSs, and eukaryotic Elongation Factor 1 Alpha (eEF1a) suggest a role of this host factor in the SFTS virus lifecycle. Subcellular localization of eEF1a in the context of SFTS virus infection showed high levels of colocalization. Treatment of infected cells with the eEF1a inhibitors Didemnin B and Ternatin showed potent, nanomolar inhibition of viral replication. Most interestingly, these inhibitors appear to inhibit SFTS virus replication at concentrations below those needed to impair protein synthesis. Differential activation of Caspase 3/7 by these inhibitors suggests a mechanism involving cell survival and apoptosis. Collectively, this work addresses multiple questions regarding the UPS in SFTS virus infection while garnering new ones. This work also sets a precedent for the use of crosslinking mass spectrometry as a tool for the study of high-containment pathogens and implicates eEF1a as an essential host factor for SFTS virus infection."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://hdl.handle.net/2152.3/12686"],"dc:subject":["Biology, Virology"],"dc:title":["NEW INSIGHTS INTO THE MOLECULAR PATHOGENESIS OF SEVERE FEVER WITH THROMBOCYTOPENIA SYNDROME VIRUS"],"dc:type":["Thesis"],"thesis:degree_name":["Experimental Pathology (Doctoral)"],"thesis:institution_name":["The University of Texas Medical Branch at Galveston"]},"updated_at":"2026-07-24T05:51:01Z"}