NF-κB is required for dengue virus NS5-induced RANTES expression

Area of Science:

• Virology
• Immunology
• Molecular Biology

Background:

• Dengue virus (DENV) infection is linked to severe renal disorders, including acute kidney injury, with high mortality rates.
• Elevated cytokine levels are implicated in DENV-induced kidney injury pathogenesis, but molecular mechanisms remain unclear.

Purpose of the Study:

• To investigate the molecular mechanisms by which DENV induces kidney cell injury, focusing on cytokine production.
• To elucidate the role of DENV NS5 protein and NF-κB signaling in regulating cytokine expression.

Main Methods:

• Utilized human cytokine RT(2) Profiler PCR array to identify differentially expressed genes in DENV-infected HEK 293 cells.
• Employed NF-κB inhibitor (compound A) and chromatin immunoprecipitation (ChIP) assays to assess RANTES regulation.
• Performed site-directed mutagenesis on NF-κB binding sites within the RANTES promoter coupled to luciferase reporter assays.

Main Results:

• DENV infection significantly upregulated 14 cytokine genes, including RANTES, IP-10, IL-8, CXCL-9, and MIP-1β.
• NF-κB inhibition suppressed RANTES expression in DENV-infected cells, indicating NF-κB involvement.
• DENV NS5 protein enhanced NF-κB binding to the RANTES promoter, and mutating NF-κB binding sites abolished NS5-mediated RANTES activation.

Conclusions:

• Dengue virus NS5 protein activates RANTES production through enhanced NF-κB binding to the RANTES promoter.
• This mechanism contributes to the cytokine dysregulation observed in DENV-associated kidney injury.