The genetic driver of Acute Necrotizing Encephalopathy, RANBP2, regulates the inflammatory response to Influenza A virus infection

Influenza virus infections can cause severe complications such as Acute Necrotizing Encephalopathy (ANE), which is characterised by rapid onset pathological inflammation following febrile infection. Heterozygous dominant mutations in the nucleoporin RANBP2/Nup358 predispose to influenza-triggered ANE1. The aim of our study was to determine whether RANBP2 plays a role in IAV-triggered inflammatory responses. We found that the depletion of RANBP2 in a human airway epithelial cell line increased IAV genomic replication by favouring the import of the viral polymerase subunits, PB1, PB2 and PA, and promoted an abnormal accumulation of some viral segments in the cytoplasm. In human primary macrophages, this corroborated with an enhanced production of the pro-inflammatory chemokines CXCL8, CXCL10, CCL2, CCL3 and CCL4. Then, using CRISPR-Cas9 knock-in for the ANE1 disease variant RANBP2-T585M, we demonstrated that the point mutation is sufficient to drive CXCL10 expression following activation downstream of RIG-I and leads to a redistribution of RANBP2 away from the nuclear pore. Together, our results reveal that RANBP2 regulates influenza RNA replication and nuclear export, triggering hyper-inflammation, offering insight into ANE pathogenesis.