Gene Expression Profile Of Chicken Central Nervous System In Newcastle Disease Virus Encephalitis

Newcastle disease(ND) is a severely infectious disease that is characterized as high fever, difficulty breathing, diarrhea and neurological symptoms. ND is caused by Newcastle disease virus(NDV), which can infect about 250 avian species, mainly including chicken, Turkey and quail in poultry. It is a great threat to poultry industry. NDV, a member of genus Avulavirus of family Paramyxoviridae, is a non-segmented, single-stranded, negative-sense RNA virus with about 15 kb genome lenght. Its genomic structure is 3’-NP-P-M-F-HN-L-5’, which encodes six structural proteins and two nonstructural proteins V and W. Chickens that are infected by virulent NDV show non-suppurative encephalitis and significant central nervous system disorders, such as twisted neck, head and neck tremors, circling, paralysis and paralysis of the legs or wings and other symptoms, and their mortality rate is 90% or more. Currently, little is known about the neuropathogenesis of NDV. In this study, we explore the differential gene expression of chicken central nervous system(CNS) infected by NDV using gene chip microarray. It would provide a valuable clue for the mechanism of NDV caused CNS diseases. The main results are following:1. Gene expression profile of chicken CNS infected by velogenic and lentogenic NDV4-week-old SPF chickens were inoculated virulent NDV strains F48E9, Yulin and attenuated vaccine strain LaSota, respectively. A non-infection group was established as control. At 5 day post-infection(dpi), the virulent stains infected groups showed the neurological symptoms and chickens were almost near to death. The LaSota and control groups did not show any clinical signs. All chickens were sacrificed, and brain samples were collected from each group. A 44 K Agilent chicken whole genome chips were used for gene expression microarray analysis. There were 429 genes were up-regulated and 267 were down regulated when both the groups F48E9 and Yulin were compared to control group. 56 differentially expressed genes were related to growth and differentiation of neronal cells, innate immunity and apoptosis. Using GO term and KEGG pathway analysis, these genes would provide potential targets for understanding the machenism of NDV neuropathogenesis in chickens.2. Sorting of major differential expression genesWe screened out significantly expressed 9 genes, which were related to the growth and differentiation of neuronal cells, such as ALDH1A2, CNTN4, CALB1 etc. The differentially expressed 31 genes were associated with innate immunity, such as TLR4、IRF7、IL18 etc. Additionally, 24 genes were concerned with apoptosis, such as APAF1、BAK1、BIRC2 etc.3. Pathological changes of chicken brains infected by velogeic and lentogenic NDVThe results of HE staining and immunohistochemical analysis showed that there were congestion and neuron soften in chicken brain tissues of which were inoculated with virulent strains F48E9 and Yulin. These data indicated a direct correlation between virulent NDV caused neurological symptoms and pathological changes in the brain tissue.