Dengue virus NS1 hits hard at the barrier integrity of human cerebral microvascular endothelial cells via cellular microRNA dysregulations.

Dengue virus (DENV) infections are commonly reported in the tropical and subtropical regions of the world. DENV is reported to exploit various strategies to cross the blood-brain barrier. The NS1 protein of DENV plays an important role in viral neuropathogenesis, resulting in endothelial hyperpermeability and cytokine-induced vascular leak. miRNAs are short non-coding RNAs that play an important role in post-transcriptional gene regulations. However, no comprehensive information about the involvement of miRNAs in DENV-NS1-mediated neuropathogenesis has been explored to date. We observed that DENV-NS1 significantly alters the cellular miRNome of human cerebral microvascular endothelial cells in a bystander fashion. Subsequent target prediction and pathway enrichment analysis indicated that these microRNAs and their corresponding target genes are involved in pathways associated with blood-brain barrier dysfunction such as "Adherens junction" and "Tight junction". Additionally, several miRNA-mRNA pairs were also found to be involved in cellular signaling pathways related to cytokine production, for instance, "Jak-STAT signaling pathway", "Chemokine signaling pathway", "IL-17 signaling pathway", "NF-κB signaling pathway", and "Viral protein interaction with cytokine and cytokine receptor". The dysregulated production of inflammatory cytokines is reported to compromise BBB permeability. This study is the first report to demonstrate that DENV-NS1-mediated miRNA perturbations are crucial in compromising endothelial barrier integrity. It also offers insights into potential therapeutic targets to mitigate DENV-NS1-induced vascular permeability and inflammation.