H9N2 AIV Affect The Expression And Distribution Of NLRP3 Inflammatory Pathway Relative Genes In Mouse

H9N2 influenza virus co?ld cause the respiratory system diseases in avain. Also H9N2 influenza virus cause great threat to human health with the ability of transmission across the host and providing the inner genes to other AIV types to form a new epidemic influenza virus(such as H7N9). Inflammatory response is important for the host antivirus infection. NLRP3 and its relative signal pathway genes play a significant role in the recognition and clearance of virus in host. The activation of NLRP3 signal pathway and the release of cytokines and chemokines help the host to resist and clear the infected virus. However the the res?lting “cytokine storm” also contributes to pathogenesis and mortality. In addition, as one of the interferon-stim?lated genes, IFITMs are widely studied for the antivirus function.However, what is the reg?lation mechanism of NLRP3 during H9N2 influenza virus infection? How the IFITMs contribute to the resistance of virus implication in host during H9N2 influenza virus infection? Co?ld the single amino acid substitution in PB2 residue 627 of H9N2 avian influenza virus change the innate immune response of host? These questions are still unclear. So in this study, we chose BABL/c mice as the animal model to study the influence of wide H9N2 avian influenza virus strain(VK627)and its single amino acid substitution in PB2 residue 627 strain(r VK627E)infection to the innate immune response of BABL/c mice from the perspective of the reg?lation of innate immune response and the mechanism of antivirus. The content of this study are showed as following.1. The influence of H9N2 avian influenza virus strain and its single amino acid substitution in PB2 residue 627 strain to the pathogenicity of BABL/c mice.Record the change of body weight and mortality of BABL/c mice from different group, and used the lungs of BABL/c mice for pathological detection. The res?lts showed that the VK627 H9N2 AIV could induce serious clinical symptom, including significant reduction in weight, serious interstitial pneumonia with the fall off of bronchial epithelial cells and inflammatory exudation, and finally lead to the death of BALB/c mice with high mortality. While single amino acid substitution in PB2 residue 627 co?ld reduce the pathogenicity of H9N2 avian influenza virus to BABL/c mice, with less weight reduction and less inflammatory exudation in the lung.2. The influence of two virus strains infection to the expression and distribution of NLRP3 and its relative genes in the lung of BABL/c mice.The expression and distribution of RIP3, NLRP3, IL-1? and TNF-? were detected by the technique of real-time PCR and immunohistochemistry. The res?lts showed that the expression levels of RIP3, NLRP3, IL-1? and TNF-? were much higher in VK627 group than that in r VK627 E group. This improved that VK627 strain and r VK627 E strain co?ld active the NLRP3 signal pathway in different degree and caused the distinct of the expression level of the downstream cytokines, which might be the possible reason for the different degree of pathological inkury in the lungs of BABL/c mice.3. The influence of two virus strains infection to the expression and distribution of SLIT2/ROBO4 in the lung of BABL/c mice.The expression and distribution of SLIT2 and ROBO4 were detected by the technique of real-time PCR and immunohistochemistry. The res?lts showed that the expression levels of SLIT2/ROBO4 were higher in r VK627 E group while were inhibited in VK627 group. This might be the reason for the different degree of pathological inkury in the lungs of BABL/c mice. These res?lts implied that the SLIT2/ROBO4 might have potential function in anti-inflammation during H9N2 influenza virus infection, however the detailed mechanism need further study.4. The influence of two virus strains infection to the expression and distribution of IFITM1/IFITM3 in the tissues of BABL/c mice.The expression and distribution of IFITM1 and IFITM3 were detected by the technique of real-time PCR and immunohistochemistry. The res?lts showed that IFITM1/IFITM3 co?ld be detected in heart, liver, spleen, lung, kidney and brain of BABL/c mice. The infection of two virus strains could change the expression pattern and distribution in tissues differently. This res?lt proved the IFITM1/IFITM3 might play potential role in host antivirus response and the single amino acid substitution in PB2 residue 627 of H9N2 influenza virus co?ld change the innate immune response mechanism and antivirus response mechanism.To sum up, this research studied the function of NLRP3 and its relative genes signal pathway in the innate immune response induced by H9N2 influenza infection and proved the single amino acid substitution in PB2 residue 627 of H9N2 influenza virus co?ld change the innate immune response mechanism and antivirus response mechanism. In addition this research firstly studied the anti-inflammation function of SLIT2/ROBO4 during H9N2 influenza virus infection, and overall exhibited the expression pattern of IFITM1/IFITM3 in the tissues of BABL/c mice. This research provided basic data for the further study of the pathological mechanism and immune response mechanism induced by H9N2 influenza virus in mammal and provided novel strategy for the prevention and cure of H9N2 influenza virus.