Role for NF-κB in herpes encephalitis pathology in mice genocopying an inborn error of IRF3-IFN immunity

Summary

Herpes simplex encephalitis (HSE) is a devastating disease with high mortality and serious sequelae. Genetic defects in the IFN-I pathway predispose individuals to HSE, but underlying mechanisms remain unclear. Using transgenic mice with the IRF3 R278Q mutation, ortholog to HSE-associated IRF3 R285Q, and iPSC-derived CNS cells from a pediatric patient carrying the variant, we investigated mechanisms in HSE. IRF3 R278Q transgenic mice exhibited aggravated HSV-1 brain disease and elevated CNS viral loads. Accordingly, microglia from the IRF3 R278Q mice showed reduced HSV-1-induced IFN-I expression. Surprisingly, unaltered Ifnb levels along with elevated levels of inflammatory cytokines were detected in infected transgenic mouse brains, correlating with higher viral load. This was successfully modeled in patient microglia. Multiomics-based immune profiling revealed an inflammatory monocyte population in the infected IRF3 R278Q mouse brain, which was enriched for NF-κB activation. NF-κB inhibition improved disease outcomes, surpassing the effect of acyclovir. These findings suggest that IFN-I defects lead to elevated levels of HSV-1 replication in the brain, which subsequently enables NF-κB-driven immunopathology, offering insights with therapeutic potential. © 2025 Idorn et al.

Authors Idorn M, Ding X, Fruhwürth S, Holste S, Reinert LS, Skoven CS, Türner-Stenström K, Schmitz A, Vendelbo MH, Ulhøi BP, Vizlin-Hodzic D, Wefelmeyer M, Narita R, Kroese LJ, Huijbers IJ, Møhlenberg M, Hollensen AK, Lai X, Iversen MB, Hansen B, Mogensen TH, Paludan SR
Journal The Journal of experimental medicine
Publication Date 2026 Jan 5;223(1)
PubMed 41065760
PubMed Central PMC12510166
DOI 10.1084/jem.20250064

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