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Biomphalaria glabrata peroxiredoxin: effect of schistosoma mansoni infection on differential gene regulation.

ABSTRACT: To identify gene(s) that may be associated with resistance/susceptibility in the intermediate snail host Biomphalaria glabrata to Schistosoma mansoni infection, a snail albumen gland cDNA library was differentially screened and a partial cDNA encoding an antioxidant enzyme thioredoxin peroxidase (Tpx), or peroxiredoxin (Prx), was identified. The 753bp full-length, single-copy, constitutively expressed gene now referred to as BgPrx4 was later isolated. BgPrx4 is a 2-Cys peroxiredoxin containing the conserved peroxidatic cysteine (C(P)) in the N-terminus and the resolving cysteine (C(R)) in the C-terminus. Sequence analysis of BgPrx4 from both resistant and susceptible snails revealed the presence of several (at least 7) single nucleotide polymorphisms (SNPs). Phylogenetic analysis indicated BgPrx4 to resemble a homolog of human peroxiredoxin, PRDX4. Northern analysis of hepatopancreas RNA from both resistant and susceptible snails showed that upon parasite exposure there were qualitative changes in gene expression. Quantitative real-time RT-PCR analysis showed differences in the levels of BgPrx4 transcript induction following infection, with the transcript up-regulated in resistant snails during the early phase (5h) of infection compared to susceptible snails in which it was down-regulated within the early time period. While there was an increase in transcription in susceptible snails later (48h) post-infection, this never reached the levels detected in resistant snails. A similar trend - higher, earlier up-regulation in the resistant snails but lower, slower protein expression in susceptible snails - was observed by Western blot analysis. Enzymatic analysis of the purified, recombinant BgPrx4 revealed the snail sequence to function as Prx but with an unusual ability to use both thioredoxin and glutathione as substrates.

SUBMITTER: Knight M

PROVIDER: S-EPMC2705950 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature

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Biomphalaria glabrata peroxiredoxin: effect of schistosoma mansoni infection on differential gene regulation.

Knight Matty M Raghavan Nithya N Goodall Cheri C Cousin Carolyn C Ittiprasert Wannaporn W Sayed Ahmed A Miller Andre A Williams David L DL Bayne Christopher J CJ

Molecular and biochemical parasitology 20090411 1

To identify gene(s) that may be associated with resistance/susceptibility in the intermediate snail host Biomphalaria glabrata to Schistosoma mansoni infection, a snail albumen gland cDNA library was differentially screened and a partial cDNA encoding an antioxidant enzyme thioredoxin peroxidase (Tpx), or peroxiredoxin (Prx), was identified. The 753bp full-length, single-copy, constitutively expressed gene now referred to as BgPrx4 was later isolated. BgPrx4 is a 2-Cys peroxiredoxin containing t ...[more]

PMID: 19439374

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Project description:Schistosomiasis is an infectious disease infecting mammals as the definitive host and fresh water snails as the intermediate host. Understanding the molecular and biochemical relationship between the causative schistosome parasite and its hosts will be key to understanding and ultimately treating and/or eradicating the disease. There is increasing evidence that pathogens that have co-evolved with their hosts can manipulate their hosts' behaviour at various levels to augment an infection. Bacteria, for example, can induce beneficial chromatin remodelling of the host genome. We have previously shown in vitro that Biomphalaria glabrata embryonic cells co-cultured with schistosome miracidia display genes changing their nuclear location and becoming up-regulated. This also happens in vivo in live intact snails, where early exposure to miracidia also elicits non-random repositioning of genes. We reveal differences in the nuclear repositioning between the response of parasite susceptible snails as compared to resistant snails and with normal or live, attenuated parasites. Interestingly, the stress response gene heat shock protein (Hsp) 70 is only repositioned and then up-regulated in susceptible snails with the normal parasite. This movement and change in gene expression seems to be controlled by the parasite. Other differences in the behaviour of genes support the view that some genes are responding to tissue damage, for example the ferritin genes move and are up-regulated whether the snails are either susceptible or resistant and upon exposure to either normal or attenuated parasite. This is the first time host genome reorganisation has been seen in a parasitic host and only the second time for any pathogen. We believe that the parasite elicits a spatio-epigenetic reorganisation of the host genome to induce favourable gene expression for itself and this might represent a fundamental mechanism present in the human host infected with schistosome cercariae as well as in other host-pathogen relationships.

Project description:The World Health Organization (WHO) estimates that approximately 240 million people in 78 countries require treatment for schistosomiasis, an endemic disease caused by trematodes of the genus Schistosoma. In Brazil, Schistosoma mansoni is the only species representative of the genus whose passage through an invertebrate host, snails of the genus Biomphalaria, is obligatory before infecting a mammalian host, including humans. The availability of the genome and transcriptome of B. glabrata makes studying the regulation of gene expression, particularly the regulation of miRNA and piRNA processing pathway genes, possible. This might assist in better understanding the biology of B. glabrata as well as its relationship to the parasite S. mansoni. Some aspects of this interaction are still poorly explored, including the participation of non-coding small RNAs, such as miRNAs and piRNAs, with lengths varying from 18 to 30 nucleotides in mature form, which are potent regulators of gene expression. Using bioinformatics tools and quantitative PCR, we characterized and validated the miRNA and piRNA processing pathway genes in B. glabrata. In silico analyses showed that genes involved in miRNA and piRNA pathways were highly conserved in protein domain distribution, catalytic site residue conservation and phylogenetic analysis. Our study showed differential expression of putative Argonaute, Drosha, Piwi, Exportin-5 and Tudor genes at different snail developmental stages and during infection with S. mansoni, suggesting that the machinery is required for miRNA and piRNA processing in B. glabrata at all stages. These data suggested that the silencing pathway mediated by miRNAs and piRNAs can interfere in snail biology throughout the life cycle of the snail, thereby influencing the B. glabrata/S. mansoni interaction. Further studies are needed to confirm the participation of the small RNA processing pathway proteins in the parasite/host relationship, mainly the effective participation of small RNAs in regulating their target genes.

Project description:Circulating hemocytes of the snail Biomphalaria glabrata, a major intermediate host for the blood fluke Schistosoma mansoni, represent the primary immune effector cells comprising the host's internal defense system. Within hours of miracidial entry into resistant B. glabrata strains, hemocytes infiltrate around developing sporocysts forming multi-layered cellular capsules that results in larval death, typically within 24-48 h post-infection. Using an in vitro model of hemocyte-sporocyst encapsulation that recapitulates in vivo events, we conducted a comparative proteomic analysis on the responses of hemocytes from inbred B. glabrata strains during the encapsulation of S. mansoni primary sporocysts. This was accomplished by a combination of Laser-capture microdissection (LCM) to isolate sections of hemocyte capsules both in the presence and absence of sporocysts, in conjunction with mass spectrometric analyses to establish protein expression profiles. Comparison of susceptible NMRI snail hemocytes in the presence and absence of sporocysts revealed a dramatic downregulation of proteins in during larval encapsulation, especially those involved in protein/CHO metabolism, immune-related, redox and signaling pathways. One of 4 upregulated proteins was arginase, competitor of nitric oxide synthetase and inhibitor of larval-killing NO production. By contrast, when compared to control capsules, sporocyst-encapsulating hemocytes of resistant BS-90 B. glabrata exhibited a more balanced profile with enhanced expression of shared proteins involved in protein synthesis/processing, immunity, and redox, and unique expression of anti-microbial/anti-parasite proteins. A final comparison of NMRI and BS-90 host hemocyte responses to co-cultured sporocysts demonstrated a decrease or downregulation of 77% of shared proteins by NMRI cells during encapsulation compared to those of the BS-90 strain, including lipopolysaccharide-binding protein, thioredoxin reductase 1 and hemoglobins 1 and 2. Overall, using this in vitro model, results of our proteomic analyses demonstrate striking differences in proteins expressed by susceptible NMRI and resistant BS-90 snail hemocytes to S. mansoni sporocysts during active encapsulation, with NMRI hemocytes exhibiting extensive downregulation of protein expression and a lower level of constitutively expressed immune-relevant proteins (e.g., FREP2) compared to BS-90. Our data suggest that snail strain differences in hemocyte protein expression during the encapsulation process account for observed differences in their cytotoxic capacity to interact with and kill sporocysts.

Dataset Information

Biomphalaria glabrata peroxiredoxin: effect of schistosoma mansoni infection on differential gene regulation.

Publications

Biomphalaria glabrata peroxiredoxin: effect of schistosoma mansoni infection on differential gene regulation.

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