| Streptococcus suis is a Gram-positive bacteria. There are 33 serotypes on clinical, Among the known 33 serotypes, Streptococcus suis serotype 2 (SS2) is the most virulent and the most frequently isolated serotype. Both humans and piglet could be infected by SS2, typical symptoms of the disease include meningitis, arthritis, endocarditis, pneumonia, septicemia and sudden death. Most of the diseases that associated to Streptococcus suis are caused by SS2 in our country. Pig industry has been seriously influenced by this kind of disease, and it is also a hazard to public health. The pathogenic mechanism of meningitis is not clear, according to the current research, SS2 either destroy the blood brain barrier(BBB) by the hemolysis or induce a high level of inflammatory factor to change the permeability of BBB, under this condition SS2 could invade into central nervous system (CNS) and final lead to meningitis. Our research use a brain tissue that infected by SS2 as material, apply porcine whole genome expression chip to do a transcriptional analysis on porcine brain tissue infected with SS2, and we do a analysis on differential expressed genes,as well as some research. Now, we report the results as follows.First we infected the weaning pigs with streptococcus suis 2(SC-19), uninfected pigs stimulate with PBS. Infected groups show typical symptom 3days after infection, the control group is healthy completely. Kill the pigs of the infected group and control group at the same time, and collect the brain tissue of each group. Prepare the total RNA to do hybridization on chips. Compared to the control group, A total of 44 differentially expressed (DE) transcripts were identified in the SS2 infected porcine brain tissue, of these,37 genes were up regulate,7 genes were down regulate.Up regulate genes include transcription factors CCAAT/enhancer-binding delta protein and CCAAT/enhancer-binding beta protein (CEBP D,CEBPB); heat shock protein 70.2(HSP70.2) and heat shock protein 27 that belong to heat shock protein family; thioredoxin interacting protein (TXNIP) that associated with clearance of oxide,and some enzymes,such as epoxide hydrolase (EPHX1),ornithine decarboxylase (ODC),prolyl 4-hydroxylase alpha (Ⅱ) subunit (P4H), and so on. Down regulate genes include retinaldehyde binding protein 1 and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, epsilon polypeptide (YWHAE) which is exclusively express in brain tissue.9 genes were picked out randomly, and the reliability of the data obtained from the microarray was verified by performing quantitative Real-time PCR on these representative genes.We do more analysis about these genes,then we adopt RT-PCR method to study 8 genes expression level in SJPLC cell line after infected by SC-19.CEBPB、EPHX1、YWHAE、PDK4、ODC show same levels to the condition when they were in brain following infected by SS2, P38、HSP70、BAG-3 are opposite. We prepared the eukaryotic expression plasmid of pcDNA3.1-ODC and pcDNA3.1-P38, our work provide the important material to do further study on gene function.Our investigation use a whole expression chip to do a research on porcine brain that infected by SS2, and verify the result by qRT-PCR, the differential expressed genes are mainly related to inflammatory and tissue injury, it suggest that SS2 may infect host by these ways, and result in encephalitis and brain tissue injury. Our study is an important fundamental research, as well as supplied important information for explaining the pathogenic mechanism of meningitis. |
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