DISTINCT ZIKV STRAIN SIGNATURES AND TYPE I IFN MODULATION REVEAL A PROTECTIVE ROLE OF BRAIN ENDOTHELIAL INTERFERON SIGNALING IN VITRO AND IN VIVO

Luan Rocha Lima¹Yasmin Mucuna Mustafá¹Paula Luize Camargos Fonseca²Sharton Vinicius Antunes Coelho¹Pierina Lorencini Parise³Camila Lopes Simeoni³Lana Monteiro Meuren¹Bruno Braz Bezerra¹Nathane Cunha Mebus-Antunes⁴Flavio Matassoli⁵José Luiz Proença-Modena³Renato Santana Aguiar^2,6Luciana Barros Arruda^1*

• ¹Universidade Federal do Rio de Janeiro Instituto de Microbiologia Professor Paulo de Goes, Rio de Janeiro, Brazil
• ²Universidade Federal de Minas Gerais Departamento de Genetica Evolucao e Ecologia, Belo Horizonte, Brazil
• ³Departamento de Genética, Microbiologia e Imunologia, Instituto de Biologia. Universidade Estadual de Campinas, Campinas, Brazil
• ⁴Universidade Federal do Rio de Janeiro Instituto de Bioquimica Medica, Rio de Janeiro, Brazil
• ⁵National Institute of Allergy and Infectious Diseases, Bethesda, United States
• ⁶Instituto D'Or de Pesquisa e Ensino, Rio de Janeiro, Brazil

Zika virus (ZIKV) infection has been associated with neurological syndromes, particularly during outbreaks caused by Asian lineage strains. However, experimental models suggest that African strains may exhibit an equal or more virulent profile. Neuroinvasion by systemic viruses often requires crossing the blood–brain barrier (BBB), which disruption amplifies viral dissemination and neuropathology. Type I interferons (IFNs) are key to restricting ZIKV replication, but their specific role in preserving BBB integrity remains poorly defined. Here, we used human brain microvascular endothelial cells (HBMECs) as a simplified BBB model to compare transcriptional responses and IFN modulation following infection with either the African prototype strain ZIKVMR766 or the Asian epidemic strain ZIKVPE243. Infection of HBMEC with ZIKVMR766 triggered a greater number and broader range of differentially expressed genes, especially ones associated with interferon signaling and translational pathways, whereas ZIKVPE243-infected samples clustered closer to non-infected ones. ZIKVMR766 infection also resulted in higher viral titers and faster dissemination across endothelial monolayers. Both strains induced IFN-β expression but suppressed downstream IFN signaling by reducing STAT1 phosphorylation and promoting STAT2 degradation, with these effects being more pronounced for ZIKVMR766. Despite these evasion mechanisms, neutralization assays revealed that endothelial cells-derived IFNs production and response partially restricted viral replication, preserved HBMEC viability, and protected against barrier disruption, with ZIKVPE243 showing greater sensitivity to IFN-β. Importantly, in vivo infection of mice lacking endothelial IFNAR signaling resulted in elevated CNS viral load and increased lethality following ZIKVMR766 infection, underscoring the pivotal role of endothelial IFN responses in viral control, maintenance of BBB integrity, and protection against neuroinvasion.