Fasciola hepatica: Characterization and Cloning of the Major Cathepsin B Protease Secreted by Newly Excysted Juvenile Liver Fluke

Wilson, Lachlan; Good, Robert T.; Panaccio, Michael; Wijffels, Gene; Sandeman, R.M.; Spithill, Terry W.

doi:10.1006/expr.1998.4234

Cited by 85 publications

(49 citation statements)

References 45 publications

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“…The network of clan CA (cathepsin B, L, and C), clan CD (legumain), and aspartic (cathepsin D) proteases functioning in the schistosome gut is remarkably similar to that found in other trematodes, such as Fasciola (48,57) and Paragonimus (58,59), and in the nematodes Ascaris (60,61), Hemonchus (62,63,64), and hookworm (3,4,8). In some cases, cathepsin L predominates versus cathepsin B (Fasciola), but the overall protease profile is strikingly similar.…”

Section: Discussionmentioning

confidence: 55%

A Multienzyme Network Functions in Intestinal Protein Digestion by a Platyhelminth Parasite

Delcroix

Sajid

Caffrey

et al. 2006

Journal of Biological Chemistry

213

205

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Proteases frequently function not only as individual enzymes but also in cascades or networks. A notable evolutionary switch occurred in one such protease network that is involved in protein digestion in the intestine. In vertebrates, this is largely the work of trypsin family serine proteases, whereas in invertebrates, cysteine proteases of the papain family and aspartic proteases assume the role. Utilizing a combination of protease class-specific inhibitors and RNA interference, we deconvoluted such a network of major endopeptidases functioning in invertebrate intestinal protein digestion, using the parasitic helminth, Schistosoma mansoni as an experimental model. We show that initial degradation of host blood proteins is ordered, occasionally redundant, and substrate-specific. Although inhibition of parasite cathepsin D had a greater effect on primary cleavage of hemoglobin, inhibition of cathepsin B predominated in albumin degradation. Nevertheless, in both cases, inhibitor combinations were synergistic. An asparaginyl endopeptidase (legumain) also synergized with cathepsin B and L in protein digestion, either by zymogen activation or facilitating substrate cleavage. This protease network operates optimally in acidic pH compartments either in the gut lumen or in vacuoles of the intestinal lining cells. Defining the role of each of these major enzymes now provides a clearer understanding of the function of a complex protease network that is conserved throughout invertebrate evolution. It also provides insights into which of these proteases are logical targets for development of chemotherapy for schistosomiasis, a major global health problem.

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Section: Discussionmentioning

confidence: 55%

A Multienzyme Network Functions in Intestinal Protein Digestion by a Platyhelminth Parasite

Delcroix

Sajid

Caffrey

et al. 2006

Journal of Biological Chemistry

213

205

View full text Add to dashboard Cite

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“…These proteases form a monophyletic group among animals but can be further divided into four clades that correspond to observed and predicted enzymatic activities (23). However, there is also substantial proteolytic activity present in the newly excysted juvenile (NEJ) and immature stages of F. hepatica, and this has been demonstrated to be mainly cathepsin protease activity, as is the case for the adult fluke stage (8,13,21,32,49). Some of this activity is due to cathepsin L-like proteases, and two cDNA clones encoding cathepsin L from NEJ have been isolated (GenBank sequences AJ279091 and AJ279093).…”

mentioning

confidence: 80%

Cloning and Expression of the Major SecretedCathepsin B-Like Protein from Juvenile Fasciola hepatica andAnalysis of Immunogenicity following Liver FlukeInfection

et al. 2003

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The functions of the cathepsin B-like proteases in liver flukes are unknown and analysis has been hindered by a lack of protein for study, since the protein is produced in small amounts by juvenile flukes. To circumvent this, we isolated and characterized a cDNA encoding the major secreted cathepsin B from Fasciola hepatica. The predicted preproprotein is 339 amino acids in length, with the mature protease predicted to be 254 amino acids long, and shows significant similarity to parasite and mammalian cathepsin B. Only one of the two conserved histidine residues required for cathepsin B exopeptidase activity is predicted to be present. Recombinant preproprotein was produced in yeast, and it was shown that the recombinant proprotein can undergo a degree of self-processing in vitro to the mature form, which is active against gelatin and synthetic peptide substrates. The recombinant protein is antigenic in vaccinated rats, and antibodies to the protein are detected early after infection of rats and sheep with F. hepatica. The kinetics of the response to cathepsin B and cathepsin L after infection of sheep and rats confirm the temporal expression of these proteins during the life cycle of the parasite.

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“…Metacercariae were excysted, and NEJ flukes were separated from empty cysts and debris by incubation overnight at 37°C as previously described (50). Cytotoxicity assays were carried out with 24-or 96-well tissue culture plates with up to 50 NEJ liver flukes per well.…”

Section: Indonesian Thin-tail (Itt) Sheep Resist Infection Bymentioning

confidence: 99%

Peritoneal Lavage Cells of Indonesian Thin-Tail Sheep Mediate Antibody-Dependent Superoxide Radical Cytotoxicity In Vitro against Newly Excysted Juvenile Fasciola gigantica but Not Juvenile Fasciola hepatica

et al. 2007

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Indonesian thin-tail (ITT) sheep resist infection byFasciola gigantica by an immunological mechanism within 2 to 4 weeks of infection yet are susceptible to F. hepatica infection. Studies of ITT sheep show that little liver damage occurs following F. gigantica infection, suggesting that the invading parasites are killed within the peritoneum or shortly after reaching the liver. We investigated whether cells isolated from the peritoneums of ITT sheep could kill newly excysted juvenile F. gigantica in vitro and act as a potential mechanism of resistance against F. gigantica infection. Peritoneal cells from F. gigantica-infected sheep, rich in macrophages and eosinophils, mediated antibody-dependent cytotoxicity against juvenile F. gigantica in vitro. Cytotoxicity was dependent on contact between the parasite and effector cells. Isolated mammary gland eosinophils of F. gigantica-infected sheep, or resident peritoneal monocytes/macrophages from uninfected sheep, also killed the juvenile parasites in vitro. By using inhibitors, we show that the molecular mechanism of killing in these assays was dependent on the production of superoxide radicals by macrophages and eosinophils. In contrast, this cytotoxic mechanism was ineffective against juvenile F. hepatica parasites in vitro. Analysis of superoxide dismutase activity and mRNA levels showed that activity and gene expression were higher in F. hepatica than in F. gigantica, suggesting a possible role for this enzyme in the resistance of F. hepatica to superoxide-mediated killing. We suggest that ovine macrophages and eosinophils, acting in concert with a specific antibody, may be important effector cells involved in the resistance of ITT sheep to F. gigantica.

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Fasciola hepatica: Characterization and Cloning of the Major Cathepsin B Protease Secreted by Newly Excysted Juvenile Liver Fluke

Cited by 85 publications

References 45 publications

A Multienzyme Network Functions in Intestinal Protein Digestion by a Platyhelminth Parasite

A Multienzyme Network Functions in Intestinal Protein Digestion by a Platyhelminth Parasite

Cloning and Expression of the Major SecretedCathepsin B-Like Protein from Juvenile Fasciola hepatica andAnalysis of Immunogenicity following Liver FlukeInfection

Peritoneal Lavage Cells of Indonesian Thin-Tail Sheep Mediate Antibody-Dependent Superoxide Radical Cytotoxicity In Vitro against Newly Excysted Juvenile Fasciola gigantica but Not Juvenile Fasciola hepatica

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