Dynamic Changes Of ATF2 And ATF3 Expression In The Cerebrum Of Mice Infection With Porcine Hemagglutinating Encephalomyelitis Virus

Porcine Hemagglutinating Encephalomyelitis Virus(PHEV)can cause lactation piglet brain showing cerebral spinal pial vascular congestion,hemorrhage and edema,a large number of lymphocytic infiltration and nodular hyperplasia of glial and neuronal degeneration,necrosis and other pathological changes of peripheral vessels.the pig is the only natural host animal,especially during the period of lactation 1～3 week newborn piglets infected mortality rate 20%～100%.Previous study showed that PHEV infection in mice after activating transcription factor 3(ATF3)gene expression was high,while the MARK signaling pathway was also induced activation and expression of the ATF3 gene is associated with positive virus replication.ATF3 can be used as a downstream target gene of ATF2.ATF2 is a member of JNK signaling pathway,which can regulate the expression of ATF3.In addition to JNK signaling pathway,ATF3 is also induced by P53,TGF-beta/smad and c-Myc signaling pathways.However,the activation of these pathways was not found in the previous experiments by using microarray technology.In this study,we first constructed a model of acute PHEV infection in mice,using the way of intracranial inoculation,the mice were killed at the fifth day of the best dose of vaccination dose.Methods 30 female SPF mice of weeks old were randomly divided into two groups:the treatment group and the control group(n = 15 in each group).In the receiving group,PHEV was inoculated with the best inoculation dose,while the control group was inoculated with PBS in the same dose.At 1,2,3,4,and 5 day,each group was randomly selected to kill 3 mice.The part of the brain is fixed in formalin solution,and the other part is frozen in liquid nitrogen.The brain fixed in formalin solution was used to observe the pathological changes of the brain;frozen in liquid nitrogen in the brain,Real-time PCR and Western-blot were used to detect the expression of ATF2 and ATF3 protein in the brain of mRNA.The expression level of ATF2,ATF3 and PHEV mRNA was detected by the relative expression of 2-△△Ct,SPSS17.0 was used to data analysis and processing,the expression of protein level was detected by semi quantitative method.The results showed that the mice infected with PHEV showed the histopathological changes of non suppurative encephalitis,and with the extension of the time of infection,the pathological damage was aggravated gradually.At the same time,the mRNA and protein expression levels of ATF2,ATF3 and PHEV were gradually increased with the extension of infection time.By correlation analysis,the expression of ATF2 and ATF3 was positively correlated(p<0.01),ATF2 expression was positively correlated with PHEV(p<0.01),the expression of ATF3 and PHEV were positively correlated(p<0.01).The peak was reached on the fifth day,and there was a significant difference between the two groups(One-Way ANOVA)(p<0.01).It means that the pathological damage in the brain of mice infected with PHEV gradually increased,and with the increase of ATF2 expression,the expression of ATF3 and PHEV viral load increased.The high expression of ATF3 in mice infected with PHEV may be mediated by ATF2 after activation of JNK signaling pathway.This study provides a new theoretical basis for the further study of the mechanism of ATF3 overexpression in the process of PHEV infection,and provides an important theoretical basis for further analysis of the molecular pathogenesis of PHEV.