Analysis On Gene Difference Expression Among Different Hosts Infected With Schistosoma Japonicum By Genome Oligonucleotide Microarray

Schistosomiasis caused by schistosome, is a wide spread parasitic zoonosis that causes serious healthy problem to both human and animals. The research useed mouse, a susceptible host of schistosome, rat, a unsusceptible host, and Microtus fortis, a resistant host, as animal model. After challenge infection, the histopathological change in lungs and livers of the three kinds of animal was observated with histochemistry technique. Gene difference expression was analysed and compared with microarray and bioinformatics technique. The dissertation focused on the different expression of immune-associated genes and development-associated genes and infered the possible response mechanisms of three kinds of animal infected with schistosome. The results were as follows:The histopathological change in lungs and livers of Microtus fortis, rat and mouse were observed by hematoxylin-eosin stain and Olympus light microscope.The Schistosoma japonicum caused more intensive immune response and pathological lesion in the body of Microtus fortis and rat than mouse, the susceptible host. Hematoxylin-eosin stain showed that the immune effector cells nearly were eosinophile granulocyte, supplemented by heterophil granulocyte, macrophage, et al, which may be one of the main reasons why Microtus fortis can naturally resist to Schistosoma japonicum.Gene difference expression of the lung and the liver tissues between Microtus fortis,rats and mice infected with Schistosoma japonicum for 10d were analyzed by oligonucleotide chip.Data analysis was performed on the basis of a significant two-fold change in signal using SpotDataTM Pro V3.0 and cluster3.0 software in order to find out gene function cluster associated with schistosomiasis resistence.Real-time PCR were used for validation. The chief results are showed as fo11ows:Ten days after challenge infection, in Microtus fortis,2678 lung and 330 liver genes with Gene Ontology annotation were up-regulated and 1748 lung and 190 liver genes were down-regulated in comparison with controls;in rats,1980 lung and 1655 liver genes were up-regulated and 2306 lung and 540 liver genes were down-regulated;in mice,364 lung and 111 liver genes were up-regulated and 16 lung and 179 liver genes were down-regulated. The differential expression was validated in 6 randomly selected genes using quantitative RT-PCR.Homologous genes of Microtus fortis,rats and mice are highlighted on the basis of a significant(Cy5/Cy3≥2.0或≤0.5). Hierarchy cluster analysis showed that 1334 lung genes were identified as differentially regulated, which were significant different in Microtus fortis, relatively different in rats and nearly basically fixed in mouse. These genes could be functionally categorized into signal transduction,transcription regulator activity,signal,cell adhesion and apoptosis. These kind of genes in liver could be functionally categorized into cytoskeleton construction,catalytic activity,metabolism,cell differentiation, immune response, growth and development. Cluster analysis showed that 74genes,including Msr1,Cnot2,C1qa,Psmb8,Itgb2,and so on,were identified as differentially regulated between the two groups.Some immune-associated genes (such as C1qa, C8a, Ctss, cgr1, cgr3, IRF-7 and CD74) in Microtus fortis infected with Schistosoma japonicum for 10 days were up-regulated. Some development-associated genes (such as Thrα, Thrsp, Hsd11β1 and IGF-1) were down-regulated while some apoptosis induction genes (such as Pdcd6, Casp7, Jak2) were up-regulated.The profound analysis on gene expression pattern suggests that the lung tissues and liver tissues of three hosts infected with Schistosoma japonicum have different response mechanisms. Microtus fortis induces immune response via Jak-STAT, VEGF, Notch and FcεR. Rat induces immune response via complement cascade pathway. Mouse induces immune response via Ca²⁺ signal pathway and the interreaction between chemotatic factor and TNF.The results reported here were meaningful for exploring the molecular mechanism of schistosoma-resistance of M.fortis , finding out the key molecule of resisting to Schistosoma japonicum, elucidate the interaction between Schistosoma japonicum and its host, bringing out a new way to develop anti-schistosomula vaccines and drugs.