Porcine transmissible gastroenteritis virus nonstructural protein 2 contributes to inflammation via NF-κB activation.

Abstract

Transmissible gastroenteritis virus (TGEV) infection causes acute enteritis in swine of all ages, and especially in suckling piglets. Small intestinal inflammation is considered a central event in the pathogenesis of TGEV infections, and nuclear factor-kappa B (NF-κB) is a key transcription factor in the inflammatory response. However, it is unclear whether NF-κB is crucial for inducing inflammation during a TGEV infection. Our results show that NF-κB was activated in swine testicular (ST) cells and intestinal epithelial cell lines J2 (IPEC-J2) cells infected with TGEV, which is consistent with the up-regulation of pro-inflammatory cytokines. Treatment of TGEV-infected ST cells and IPEC-J2 cells with the NF-κB-specific inhibitor caused the down-regulation of pro-inflammatory cytokine expression, but did not significantly affect TGEV replication. Individual TGEV protein screening results demonstrated that Nsp2 exhibited a high potential for activating NF-κB and enhancing the expression of pro-inflammatory cytokines. Functional domain analyzes indicated that the first 120 amino acid residues of Nsp2 were essential for NF-κB activation. Taken together, these data suggested that NF-κB activation was a major contributor to TGEV infection-induced inflammation, and that Nsp2 was the key viral protein involved in the regulation of inflammation, with amino acids 1-120 playing a critical role in activating NF-κB. Abbreviations: TCID50: 50% tissue culture infectious dose; DMEM: Dulbecco's Modified Eagle Medium; eNOS: Endothelial nitric oxide synthase; FBS: fetal bovine serum; IFA: Indirect immunofluorescence; IκB: inhibitor of nuclear factor kappa-B; IL: interleukin; IPEC-J2: intestinal epithelial cell lines J2; IKK: IκB kinase; Luc: luciferase reporter gene; mAbs: monoclonal antibodies; MOI: multiple of infection; Nsp: nonstructural protein; NF-κB: nuclear factor-kappa ; ORFs: open reading frames; PBS: phosphate-buffered saline; p65 p-p65: phosphorylated; RT-PCR: reverse transcription PC; SeV: Sendai virus; ST: swine testicular; TGEV: Transmissible gastroenteritis virus; TNF-α: tumor necrosis factor α; UV-TGEV: Ultraviolet light-inactivated TGEV; ZnF: zinc finger.

• Authors: Li Wang, Xinyuan Qiao, Sijia Zhang, Yue Qin, Tiantian Guo, Zhenye Hao, Li Sun, Xiaona Wang, Yanan Wang, Yanping Jiang, Lijie Tang, Yigang Xu, Yijing Li
• Journal: Virulence (Virulence) Vol. 9 Issue 1 Pg. 1685-1698 ( 2018) ISSN: 2150-5608 [Electronic] United States
• PMID: 30322331 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Cytokines
• NF-kappa B
• Viral Nonstructural Proteins

Topics

• Animals
• Cell Line
• Cytokines (immunology)
• Epithelial Cells (virology)
• Gastroenteritis, Transmissible, of Swine (immunology)
• Gene Expression Regulation, Viral
• Inflammation
• Intestines (cytology, virology)
• NF-kappa B (antagonists & inhibitors, immunology)
• Phosphorylation
• Swine
• Transmissible gastroenteritis virus (chemistry, immunology)
• Viral Nonstructural Proteins (immunology)
• Virus Replication