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| Author(s): |
Katia Cristina Pereira Oliveira Santos
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2009-09-30 |
| Examining board members: |
Sérgio Verjovski Almeida;
Hugo Aguirre Armelin;
Walter Colli;
Glória Regina Franco;
Guilherme Corrêa de Oliveira
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| Advisor: | Sérgio Verjovski Almeida |
| Abstract | |
The parasite Schistosoma mansoni is one of major causative agents of schistosomiasis, a disease which affects 200 million people in the world. The parasite has a complex life cycle with six developmental stages in two hosts. S. mansoni has a sofisticated system of interaction with the hosts, permitting it to escape the immune response and to interact with molecules produced by the hosts. The effect of human TNF-α on adult parasite egg-laying has been described in the literature. The present work intended to analyse the gene expression profile of S. mansoni among its developmental stages, to evaluate the effect of human TNF-α on gene expression profile in two different developmental stages and to describe a homologous gene to human TNF-α receptor in S. mansoni. Two microarrays platfoms were used: one comprised by 4000 cDNA probes and printed by our research group and another, comprised by 44000 oligonucleotide probes designed by our group and printed by Agilent Technologies Company. With these platforms, we detected the expression of 5798 genes in adult worms, of which 156 showed transcription in sense and anti-sense strands; 6 of them had their expression levels confirmed by strand specific Real Time PCR. 229 genes were identified as differentially expressed between male and female adult worms. Gene expression analysis among 5 parasite developmental stages identified two data sets: (i) 1423 differentially expressed genes between two subsequent developmental stages and (ii) 342 expressed genes enriched in one exclusive stage. 68 of them are intronic transcripts with no protein-coding potential. An ortologue to human TNF-α receptor (SmTNFR) was cloned and sequenced. SmTNFR transcritpt has 1967bp and encodes a 599-amino acid protein. Other 9 genes encoding conserved elements of the TNF-α signaling pathway were identified among the public S. mansoni ESTs dataset, thus revealing a complete TNF-α signaling pathway in the parasite. Finally, we identified with microarrays the set of genes that have an altered gene expression upon exposure of schistosomula and adult worms to human TNF-α. 340 genes were identified with altered expression in adult worms using the cDNA platform. 411 genes changed their expression pattern in schistosomula and 1093 genes in adult worms using the oligonucleotide platform. This work represents an important contribution to the understanding of host-parasite interaction at the molecular level. (AU) | |