Taurine ameliorates viral encephalitis by restoring PRKN-mediated mitophagy

Mitophagy is a selective type of autophagy that removes damaged mitochondria to maintain mitochondrial homeostasis and regulate the antiviral immune response. Despite increasing evidence that herpes simplex virus type 1 (HSV-1) infection causes mitochondrial damage, the regulatory mechanisms governing mitochondrial homeostasis and its biological implications in the context of HSV-1 infection and viral encephalitis remain unclear. In our recent work, we find that HSV-1 infection causes the accumulation of damaged mitochondria via defective mitophagy in vitro and in brain tissue of mice. The viral proteins ICP34.5 and US11 inhibit the EIF2S (eukaryotic translation initiation factor 2 subunit alpha)-ATF4 (activating transcription factor 4) axis to transcriptionally suppress PRKN/Parkin expression and subsequently impede PRKN-dependent mitophagy. Consequently, modulation of mitophagy significantly affects HSV-1 infection and NFKB/NF-κB-mediated neuroinflammation, as well as the severity of viral encephalitis in mice. Moreover, taurine, a metabolite differentially regulated by HSV-1 infection, transcriptionally promotes PRKN-mediated mitophagy, thereby limiting HSV-1 infection both in vitro and in vivo. This work reveals a protective function of mitophagy in restricting viral encephalitis and highlights the ATF4-PRKN axis as a potential therapeutic approach for the treatment of neurotropic virus-related diseases.Abbreviations: Aβ: amyloid β protein; AD: Alzheimer disease; ATF4: activating transcription factor 4; EIF2AK2/PKR: eukaryotic translation initiation factor 2 alpha kinase 2; EIF2S1: eukaryotic translation initiation factor 2 subunit alpha; HSE: herpes simplex encephalitis; HSV-1: herpes simplex virus type 1.