| Toxoplasmosis is one of the most important zoonoses, which is caused by the obligate intracellular protozoan parasite Toxoplasma gondii infecting all warm-blooded animals and human beings globally. It is estimated that T. gondii infects up to one-third of the human population in the world and a mean infection rate of 7.88% in China, even higher in animals. In recent years, with the development of economy and the improvement of people’s living standard, keeping pets has become a fashion. However, pets have become to spread many infectious diseases due to the management confusion of pet markets, backward techniques for detecting diseases and the lack of the vaccines. However, limited information about human toxoplasmosis in China is available. Moreover, the main reason that animal and human toxoplasmosis has not been controlled well is due to the insufficiency in its basic research, particularly it is yet to understand the mechanism underlying the interaction between T. gondii and its definitive hosts(domestic cats). Thus, it is necessary to investigate human infection with T. gondii infection in China and study the molecular mechanism of the interaction between T. gondii and its definitive hosts(cats).In the present study, we investigated the seroprevalence of T. gondii infection in humans by ELISA in some regions in our country and identified the genotypes of T.gondii in cancer patients by PCR-RFLP. Furthermore, Using RNA-Seq, i TRAQ,bioinformatics analysis, fluorescence quantitative PCR, and multiple reaction monitoring techniques, differentially expressed genes and proteins in the brain, heart,liver, spleen, lung, and small intestine of cats after T. gondii infection were identified.(1) The overall seroprevalence of T. gondii infection in children was 15.13%.Raising cats at home and hand-washing habit were estimated to be risk and protective factors, respectively, associated with Toxoplasma seroprevalence.(2) The seroprevalence of T. gondii infection in pregnant women(15.2%) was lower than that in controls(17.3%). T. gondii infection was associated with location,cats in the home, contact with cats and dogs, and exposure to soil.(3) The seroprevalence of T. gondii infection in psychiatric patients(17.30%) was significantly higher than control subjects(12.36%)(P<0.05). Schizophrenic patients have a significantly higher seroprevalence than control subjects(P=0.001). T. gondii infection was associated with cats at home and consumption of raw/undercooked meat in psychiatric patients.(4) The prevalence of anti-T. gonii IgG in cancer patients(35.56%) was significantly higher than that in controls(17.44%)(P<0.05). The highest T. gondii seroprevalence was detected in lung cancer patients(60.94%). Exposure with soil and consumption of raw/undercooked meat were significantly associated with T. gondii infection in cancer patients(P<0.05). Three T. gondii genotypes(Toxo DB#9,Toxo DB#10 and Type I variant) were identified from the patients with positive ELISA result by PCR-RFLP.(5) Using RNA-Seq technique, bioinformatics analysis and fluorescence quantitative PCR, we examined the transcriptomes of cats after T. gondii infection and identified differentially expressed genes in the brain, heart, liver, spleen, lung, and small intestine of cats. Three differentially expressed genes were found in the brain,118 in the heart, 163 in the liver, 23 in the spleen, 12 in the lung and 106 in the small intestine. Through Gene Ontology(GO) and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathways analysis, we identified differentially expressed genes involved in some important immune processes and signaling pathways.(6) Using i TRAQ technique, bioinformatics analysis and multiple reaction monitoring technique, we examined the proteomes of cats after T. gondii infection and identified differentially expressed proteins in the brain, heart, liver, spleen, lung,and small intestine of cats. One hundred and three differentially expressed proteins were found in the brain, 401 in the heart, 341 in the liver, 107 in the spleen, 162 in the lung and 316 in the small intestine. Functional analysis using Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathways database showed that differentially expressed proteins were mainly involved in metabolism, cell structure, signal transduction and immune responses.(7) We performed correlation analysis between transcriptomes and proteomes of cats and found that 29 differentially expressed genes were up to expression standard.Of these, four were in the heart, four in the lung, 16 in the small intestine and 5 in the liver. In the present study, the degree of correlation between transcriptomes and proteomes of cats was low.In this work, we investigated the seroprevalence of T. gondii infection in humans in some regions in China and firstly identified the T. gondii genotypes in cancer patients in China. Moreover, we studied the transcriptomic and proteomic profiles of major tissues of domestic cats after infection with T. gondii by an integrated approach using RNA-Seq, i TRAQ, bioinformatics analysis, fluorescence quantitative PCR, and multiple reaction monitoring techniques for the first time. We also performed correlation analysis between transcriptomes and proteomes of cats. These results will contribute to the research of human toxoplasmosis in our country and to the better understanding of the T. gondii-definitive host interaction and relationship relating to invasion and pathogenesis. |
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