Pseudorabies virus infection induces IRF1-dependent PANoptosis to provoke the excessive release of HMGB1 and IL-1β

PANoptosis is a newly described type of cell death that can be triggered upon microbial infection, autoinflammatory diseases, and cytokine storms, and involves the coordinated activation of pyroptosis, apoptosis, and necroptosis. Pseudorabies virus (PRV) infection has been reported to trigger excessive inflammatory responses in mice, swine, and in rare cases in humans, leading to acute viral encephalitis. However, the precise mechanisms by which PRV exacerbates host inflammation responses remain incompletely understood, and the potential role of PANoptosis in this pathogenic process has yet to be elucidated. Here, we demonstrate that PRV infection in different cell lines, murine primary macrophages and mice all results in activation of the PANoptotic signaling pathway and drives the formation of the core scaffold (caspase-8/ASC/RIPK3) within the PANoptosome. We observe that innate sensor proteins AIM2, Pyrin, and ZBP1 interact with the core scaffold protein ASC in PRV-infected THP-1 Mφ and co-localize with ASC. We further identify that IRF1 serves as the key transcription factor that is upregulated during PRV infection. Increased IRF1 translocates to the nucleus and binds directly to the promoter regions of innate sensor genes ZBP1 and AIM2, thereby elevating their gene expression. Ultimately, we discover that the genetic suppression of IRF1 expression and pharmacological blockade of PANoptosis markedly attenuate the extracellular release of pro-inflammatory mediators HMGB1 and IL-1β during PRV infection in vitro. Moreover, pharmacological inhibition of PANoptosis in vivo substantially reduces levels of HMGB1 and IL-1β in cerebral tissue of PRV-infected mice and effectively confers significant protection against PRV challenge, supporting an important role for PANoptosis in PRV pathogenesis. Collectively, our study not only provides a novel perspective on the pro-inflammatory mechanisms of PRV but also highlights that PANoptosis may be therapeutically targeted to improve viral infection outcomes.