Many vector-borne viruses are re-emerging as public health threats, yet our understanding of the virus–host interactions critical for productive infection remains limited. The ubiquitination of proteins, including host- and pathogen-derived proteins is a highly prominent and consistent post-translational modification that regulates protein function through signaling and degradation. Viral proteins are documented to hijack the host ubiquitination machinery to modulate multiple host processes including antiviral defense mechanisms. The engagement of the host ubiquitination machinery in the post-translational modification of viral proteins to support aspects of the viral life cycle including assembly and egress is also well documented. Exploring the role ubiquitination plays in the life cycle of vector-transmitted viral pathogens will increase the knowledge base pertinent to the impact of host-enabled ubiquitination of viral and host proteins and the consequences on viral pathogenesis. In this review, we explore E3 ligase-regulated ubiquitination pathways functioning as proviral and viral restriction factors in the context of acutely infectious, vector-transmitted viral pathogens and the potential for therapeutically targeting them for countermeasures development.

Arthropod-borne viruses such as Alphaviruses and Flaviviruses are the causative agents of severe human disease, highlighted by fatal encephalitis and neurological sequelae in survivors. The lack of FDA-approved vaccines and therapeutics that can prevent or treat these infections results in a significant global disease burden. An important unmet need to address this capability gap is the need for affordable, scalable, clinically relevant human-based neuronal models to study neuroinvasive viruses and evaluate therapeutic options. Here, we described the application of a human neuronal precursor cell model, LUHMES (Lund human mesencephalic) cells, that can be differentiated into dopaminergic midbrain neurons and used to study virus infections. In this study, we demonstrated the susceptibility of LUHMES cells to infection by three arthropod-borne neurotropic viruses: Venezuelan equine encephalitis virus, dengue virus serotype 2, and West Nile virus. We also demonstrated how the model may be applied to evaluate potential therapeutic options using an FDA-approved small molecule, Omaveloxolone. Finally, we analyzed host cell responses to infection and treatment using gene expression and phospho-signaling analyses. These findings highlight the value of this model to interpret the pathogenic mechanisms of neurotropic viral infections and evaluate potential therapeutic intervention strategies in a clinically relevant in vitro human neuronal model.

Early stages of host–virus interactions in peripheral tissues, such as the liver, are critical yet understudied determinants of alphavirus pathogenesis. We utilized a liver organ-on-a-chip (OOC) model consisting of primary human hepatocytes (PHHs) and Kupffer cells (KCs) to enable time-resolved tracking of Venezuelan equine encephalitis virus vaccine strain TC-83 (VEEV TC-83) replication kinetics, tissue damage, and host immunopathology. This platform was employed to evaluate the host-directed therapeutic Omaveloxolone (OMA), a known nuclear factor erythroid 2-related factor 2 (Nrf2) activator. Productive VEEV infection induced acute liver injury, indicated by parallel increases in supernatant alanine aminotransferase (ALT) and lactate dehydrogenase (LDH), alongside the newly identified pathogen-associated biomarkers $\gamma$-enolase (ENO2) and complement factor H-related protein 3 (CFHR3). Post-infection treatment with OMA within a nontoxic range altered inflammatory responses and modestly reduced viral load during the early stages, although this inhibitory efficacy was lost at later time points. Collectively, this OOC model enables the investigation of organ-specific events, demonstrating that peripheral liver responses to VEEV involve coordinated inflammatory and proteomic alterations that culminate in acute liver injury, potentially contributing to systemic inflammation and overall alphavirus disease severity.