Comparative Proteomics Of Rabies Virus Infection

Rabies is a zoonotic disease that remains an important public health problem worldwide and causes more than 55,000 human deaths each year. The causative agent of rabies is rabies virus (RV), a negative-stranded RNA virus of the rhabdovirus family. Neuroinvasiveness and neurotropism are the main features that define the pathogenesis of rabies. Since human rabies is nearly 100% fatal if prophylactic measures are not followed, an increased awareness of who should receive prophylaxis and when prophylaxis should be administered is necessary. Preexposure prophylaxis entails the administration of the rabies vaccine to individuals at high risk for exposure to rabies viruses.With the advancements of modern biotechnology, knowledge of this disease has been understood more and more profoundly. Despite the fact that rabies is one of the oldest known human infections, the pathogenic mechanism by which rabies virus infection leads to the development of neurological diseases and death is not well understood. The complex relationship of rabies virus with the host leads to its replication and spreading toward the neural network, where viral pathogenic effects appeared as neuronal dysfunction. However, there are few reports about the models of virus and cells interaction when RV infects host cells, as well as the data of different responses when cells are infected by different virulence RV strains.Through two-dimensional electrophoresis gel (2-DE), mass spectrum appraisal, protein database analysis and other proteomics technologies, the difference of response proteins in cells under different status, including the infection by different virulence of rabies virus, could be explored. In order to better understand the molecular basis of this relationship, the authers employed proteomics technology to profile the responses to RV infection in N2a cells and mouse brain.Firstly, Comparative proteomics technology has been applied to describe the responses of N2a cells infected with 3 different virulent rabies virus strains (the virulent BD06, the fixed CVS-11 and the attenuated SRV9). Altered expressions of 41 protein spots in the infected cells at 48h.p.i. were identified in 2-DE gels, with 32 of which being characterized by MALDI-TOF-MS/MS. These proteins are involved in the cytoskeleton, signal transduction, stress response, and metabolic processes. Some of the differential expression proteins were commonly changed when the 3 RVs infect N2a cells, such as a-enolase, prx-4, vimentin, CIAPIN1 and prx-6, which presented up-regulated expression, while Trx like-1 and galectin-1 presented down-regulated expression. The up-regulation of vimentin and CIAPIN1 as well as down-regulation of Galectin-1 with all 3 viruses, compared with the uninfected cotrol cells, was confirmed by western-blot analysis. Comparing the protein profiles between cells infected with BD06, CVS-11 and SRV9, significant changes in expression were observed. The up-regulation of vimentin, CIAPIN1, prx-4 and 14-3-3θ/δ, and the down-regulation of NDPK-B and HSP-1 in CVS and SRV9 were≥2 times more than in BD06. Meanwhile, Zfp12 protein, splicing factor and arginine/serine-rich 1 were unanimous in the two groups infected with BD06 and CVS-11, while they were up-regulated in the group infected with SRV9.Secondly, comparative proteomics technology has been applied to describe the responses of mouse brain infected with BD06 and SRV9. Altered expressions of 9 protein spots in the infected cells at 48h.p.i. were identified in 2-DE gels, with 8 of which being characterized by IMMS. These 8 differentially expressed proteins perhaps the reason was that the difference of RV different virulence strains lead to the different pathogenicity of infected mouse brain.Thirdly, using comparative proteomics technology, we studied the response patterns of 10d and 20d sucking mouse brain infected with SRV9. Altered expressions of 10 protein spots in the infected cells at 48h.p.i. were identified in 2-DE gels, with 8 of which being characterized by IMMS. The reason of the 8 differentially expressed proteins perhaps that the difference sensitivity to different age sucking mouse of SRV9.This study suggested differential expression data of cellular proteome of N2a and mouse brain infected with RV and provided the reference to the further research on RV infection and pathogenic mechanism. These differential expression proteins showed that there were differences among the reaction model when host cells were infected by RV, and the suitability of different cells and different virulence RV strains infection. Clearly, further large scale studies are necessary to understand the roles of the differential expressed cellular proteins in RV infection.