The H9N2 avian influenza virus is a pandemic threat which has repeatedly caused infection in humans and shows enhanced replication and transmission in mice. Previous reports showed that host factors, the interferon-inducible transmembrane (IFITM) protein, can block the replication of pathogens and affect their pathogenesis. BALB/c mice are routine laboratory animals used in influenza virus research, but the effects of H9N2 influenza virus on tissue distribution and expression pattern of IFITM in these mice are unknown. Here, we investigated the expression patterns and tissue distribution of IFITM1 and IFITM3 in BALB/c mice by infection with H9N2 AIV strains with only a PB2 residue 627 difference. The results showed that the expression patterns of ITITM1 and IFITM3 differ in various tissues of BALB/c mice at different time points after infection. IFITM1 and IFITM3 showed cell- and tissue-specific distribution in the lung, heart, liver, spleen, kidney and brain. Notably, the epithelial and neuronal cells all expressed the proteins of IFITM1 and IFITM3. Our results provide the first look at differences in IFITM1 and IFITM3 expression patterns in BALB/c mice infected by H9N2 influenza viruses. This will enhance research on the interaction between AIV and host and further will elucidate the pathogenesis of influenza virus infection based on the interferon-inducible transmembrane (IFITM) protein.

Pathogen-associated molecular patterns (PAMPs) play important role in inflammation which means response of the host to stimuli. NOD-like receptor protein 3 (NLRP3) inflammasome is involved in the onset and development of inflammation. NLRP3, as one of the most important inflammasome sensors, has significant effect on the regulation of inflammasome activation to avoid the consequences of over activation. Up to date, there are no detailed tissue specific expression and distribution data about NLPR3 in chicken. Here, NLRP3 of Chinese yellow chicken was cloned and sequence analyzed, the polyclonal antibody was produced by purified protein of recombinant prokaryotic expression. Relative expression levels and tissue distribution of NLRP3 were investigated by real-time quantitative PCR and immunohistochemical analysis, respectively. The results showed that NLRP3 gene is highly variable between mammalian and avian. The nucleotide homology of NLRP3 between yellow chicken and Bos taurus, Hainan black goat, Sus scrofa, Callithrix jacchus, Homo sapiens, Macaca mulatta, Mus musculus and Rattus norvegicus were 54.2%, 53.9%, 53.7%, 55.4%, 54.3%, 54.5%, 53.5% and 53.7%. NLRP3 expressed in all detected tissues and higher in the trachea are lung than in other tissues. Cytoplasmic expression of NLRP3 was detected in ciliated epithelial cells, basal cells and cells in lamina propria of trachea, alveolar epithelial cells, cardiac muscle cells, cerebral cortex neurons, epithelial reticular cells of the spleen, and lymphocytes of medulla in stannius follicle, liver cells and the renal tubule epithelial cells. The results will help to elucidate the role of NLRP3 of different tissues in inflammatory diseases of chicken and provide a basis for further investigations in the function and evolution of NLRP3 in different species, which would be helpful for further research on avian inflammatory diseases.

MicroRNAs (miRNAs) play key roles in the regulation of gene expression during multiple physiological processes, including early development, differentiation, and ageing. However, their involvement in age-related thymic involution is not clear. In this study, we profiled the global transcriptome and miRNAome of thymic epithelial cells in 1- and 3-month-old male and female mice, and predicted the possible transcription factors and target genes of the four most significantly differentially expressed miRNAs (DEMs) (miR-183-5p, miR-199b-5p, miR-205-5p, and miR-200b-3p) by performing bioinformatics analyses. We also evaluated the relationships between the significantly DEMs and mRNAs. We performed quantitative polymerase chain reaction to confirm the changes in the expression of the miRNAs and their predicted target genes. We found that miR-183-5p, miR-199b-5p, miR-205-5p, and miR-200b-3p can be used as a biomarker group for mouse thymus development and involution. In addition, the predicted target genes (Ptpn4, Slc2a9, Pkib, Pecam1, and Prkdc), which were identified by mRNA sequencing analysis, were mainly involved in growth, development, and accelerated senescence. In conclusion, miRNAs and their predicted target genes likely play important roles in thymus development and involution. To the best of our knowledge, this is the first study to systematically analyze the relevance of miRNAs and their targets by mRNA sequencing in mouse thymic epithelial cells. © 2018 IUBMB Life, 70(7):678-690, 2018.

H7N9 influenza A virus (IAV)-infected human cases are increasing and reported over 200 mortalities since its first emergence in 2013. Host inflammatory response contributes to the clearance of influenza virus; meanwhile, the induced "cytokine storm" also leads to pathological lesions. However, what inflammation-related response of the host for H7N9 influenza A virus infection to survival from injures of exuberant cytokine release is still obscure. In this research, expression pattern and histological distribution of inflammation-related genes, RIP3, NLRP3, IL-1β, TNF-α, Slit2 and Robo4 in the lung of BALB/c mice infected with two H7N9 IAV strains with only a PB2 residue 627 difference were investigated, as well as the histopathological injury of the lung. Results showed that significantly higher expression level of NLRP3, RIP3, IL-1β and TNF-α in H7N9-infected groups compared with the control would play a key role in driving lung pathological lesion. While the expression level of Slit2 and Robo4 in H7N9 rVK627E group had significantly increased trend than VK627 which might be the main factor to inhibit the interstitial pneumonia and infiltration. Also, H7N9 induced the histopathological changes in the lung of infected mice, and RIP3, NLRP3, IL-1β, TNF-α, Slit2 and Robo4 showed cell-specific distribution in the lung. The results will provide basic data for further research on the mechanism of inflammatory response and understanding of the role of site 627 in PB2 in H7N9 IAVs infection. In addition, enhancing the resilience of the host vascular system to the inflammatory response by regulation of Slit2-Robo4 signaling pathway might provide a novel strategy for H7N9 IAVs infection.

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