Seneca Valley virus 3C protease cleaves OPTN (optineurin) to Impair selective autophagy and type I interferon signaling

ABSTRACT

Seneca Valley virus (SVV) causes vesicular disease in pigs, posing a threat to global pork production. OPTN (optineurin) is a macroautophagy/autophagy receptor that restricts microbial propagation by targeting specific viral or bacterial proteins for degradation. OPTN is degraded and cleaved at glutamine 513 following SVV infection via the activity of viral 3C protease (3C[pro]), resulting in N-terminal and a C-terminal OPTN fragments. Moreover, OPTN interacts with VP1 and targets VP1 for degradation to inhibit viral replication. The N-terminal cleaved OPTN sustained its interaction with VP1, whereas the degradation capacity targeting VP1 decreased. The inhibitory effect of N-terminal OPTN against SVV infection was significantly reduced, C-terminal OPTN failed to inhibit viral replication, and degradation of VP1 was blocked. The knockdown of OPTN resulted in reduced TBK1 activation and phosphorylation of IRF3, whereas overexpression of OPTN led to increased TBK1-IRF3 signaling. Additionally, the N-terminal OPTN diminished the activation of the type I IFN (interferon) pathway. These results show that SVV 3C[pro] targets OPTN because its cleavage impairs its function in selective autophagy and type I IFN production, revealing a novel model in which the virus develops diverse strategies for evading host autophagic machinery and type I IFN response for survival.

Abbreviations: Co-IP: co-immunoprecipitation; GFP-green fluorescent protein; hpi: hours post-infection; HRP: horseradish peroxidase; IFN: interferon; IFNB/IFN-β: interferon beta; IRF3: interferon regulatory factor 3; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MOI: multiplicity of infection; OPTN: optineurin; PBS: phosphate-buffered saline; SVV: Seneca Valley virus; SQSTM1: sequestosome 1; TAX1BP1: Tax1 binding protein 1; TBK1: TANK binding kinase 1; TCID50: 50% tissue culture infectious doses; UBAN: ubiquitin binding in TNIP/ABIN (TNFAIP3/A20 and inhibitor of NFKB/NF-kB) and IKBKG/NEMO; UBD: ubiquitin-binding domain; ZnF: zinc finger.

KEYWORDS:

• 3C protease (3C[pro])
• cleavage
• OPTN (optineurin)
• selective autophagy
• Seneca Valley virus (SVV)
• type I interferon (IFN)

Disclosure statement

The authors have no financial conflicts of interest.

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

This work was supported by the Outstanding Young Foundation of Beijing Academy of Agriculture and Forestry Sciences (YXQN202302), the Innovation Capacity of Beijing Academy of Agriculture and Forestry Sciences (KJCX20220411), the Reform and Development of Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences (XMS202312), Key Laboratory of Livestock Infectious Diseases, Ministry of Education, Shenyang Agricultural University (FKLID-2021-03), and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).