Classical swine fever virus NS5A protein changed inflammatory cytokine secretion in porcine alveolar macrophages by inhibiting the NF-κB signaling pathway.
Classical swine fever (CSF) caused by CSF virus (CSFV) is a highly contagious disease of the pigs. A number of studies have suggested that CSFV non-structural (NS) 5A protein is involved in CSFV-associated pathogenesis, but its mechanism is still uncertain. The aim of this study was to investigate the roles of NS5A protein in CSFV-associated pathogenesis in cultured porcine alveolar macrophages (PAMs).



After PAMs cultured in vitro were transfected with CSFV NS5A, the alterations in IL-1β, IL-6 and TNF-α expression were determined by ELISA, the RIG-I signaling activity related to inflammatory cytokine secretion was investigated by Western blot and Immunofluorescent staining.



It was suggested that, the stable expressed CSFV NS5A solely had no influence on the expressions of inflammatory cytokines IL-1β, IL-6 and TNF-α in PAMs Moreover, NS5A protein could suppressed IL-1β, IL-6 and TNF-α expression induced by poly(I:C). It was also showed that NS5A protein did not impair the expressions of RIG-I, MDA5, IPS-1, NF-κB and IkBα in cells without poly(I:C) stimulation. Protein expressions of RIG-I, MDA5, IPS-1, NF-κB were not disrupted by NS5A protein in poly(I:C)-stimulated cells, while poly(I:C)-induced NF-κB nuclear translocation and activity was obviously suppressed by this protein. A suppression in poly(I:C)-induced IkBα degradation in NS5A-expressing cells was also observed.



These data indicated that CSFV NS5A protein could inhibit the secretion of inflammatory cytokine induced by poly(I:C) through the suppression of the NF-κB signaling pathway, indicating the participation of CSFV NS5A protein in the pathogenesis of CSFV.
College of Yingdong Agricultural Science and Engineering, Shaoguan University, Daxue Road, Zhenjiang District, Shaoguan, 512005, China.|North Guangdong Collaborative Innovation and Development Center for Swine Farming and Disease Control, Shaoguan, 512005, China.
Xiao-Ying
XY
Dong
College of Yingdong Agricultural Science and Engineering, Shaoguan University, Daxue Road, Zhenjiang District, Shaoguan, 512005, China. willertang@163.com.|North Guangdong Collaborative Innovation and Development Center for Swine Farming and Disease Control, Shaoguan, 512005, China. willertang@163.com.
Sheng-Qiu
SQ
Tang
D000818:Animals; D006691:Classical Swine Fever / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D006692:Classical Swine Fever Virus / Q000235:genetics / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D006790:Host-Parasite Interactions; D053583:Interleukin-1beta / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D016676:Macrophages, Alveolar / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D013552:Swine; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
D016207:Cytokines; D053583:Interleukin-1beta; D015850:Interleukin-6; D016328:NF-kappa B; D017361:Viral Nonstructural Proteins
CSFV; Cytokine; NF-κB; NS5A; RIG-I