Lumpy skin disease virus ORF142 suppresses the cGAS/STING-mediated IFN-I pathway through NBR1-mediated STING autophagic degradation

Abstract

Lumpy skin disease (LSD), caused by the Lumpy skin disease virus (LSDV), poses a significant threat to the global cattle farming industry. Viral proteins evolved the ability to escape host immune responses. Here, we demonstrate that LSDV infection inhibits interferon-β (IFN-β) production in Madin-Darby bovine kidney (MDBK) cells, even in the presence of Sendai virus (SEV) inducers. Through further investigation, we identify multiple genes at both ends of the LSDV genome that strongly inhibit IFN-β or NF-κB activation of the promoter. Notably, ORF142 selectively inhibits IFN-β promoter activity but fails to inhibit NF-κB promoter activity. Subsequently, we reveal that ORF142 negatively regulate the cGAS/STING-mediated IFN-I production. Overexpression of ORF142 suppresses IFN-β and interferon-stimulated response element (ISRE) activity, while the absence of ORF142 upregulates the transcription levels of IFN-β and interferon-stimulated genes (ISGs) in MDBK cells. Mechanistically, ORF142 interacts with STING to facilitate autophagy-lysosomal degradation by recruiting NBR1, thereby impeding the activation of downstream signaling molecules, such as IRF3, and inhibiting IFN-I production. In conclusion, our findings elucidate the immune evasion mechanism of ORF142 encoded by LSDV, offering insights for the development of antiviral drugs or attenuated live vaccines to mitigate LSD.