Proteolysis of human hemoglobin by schistosome cathepsin D

Brindley, Paul J.; Kalinna, Bernd H.; Wong, Joanna Y.M.; Bogitsh, Burton J.; King, Lynette T.; Smyth, Danielle J.; Verity, Christiana K.; Abbenante, Giovanni; Brinkworth, Ross I.; Fairlie, David P.; Smythe, Mark L.; Milburn, Peter J.; Bielefeldt‐Ohmann, Helle; Zheng, Ying; McManus, Donald P.

doi:10.1016/s0166-6851(00)00351-0

Cited by 107 publications

(98 citation statements)

References 31 publications

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“…Our experiment targeted dsRNA to three-hour old somules. If as hypothesized [15] the dsRNA enters through these glands of three-hour-old schistosomules, it may spread to the developing gut and gastrodermis where cathepsin D has been localized in older, blood stage schistosomes [6,11].…”

Section: Discussionmentioning

confidence: 94%

“…The requisite initial cleavages of the hemoglobin monomer that have been determined for this enzyme, e.g. α-chain Phe33-Phe34 and β-chain Phe41-Phe42 [6,11], may not have occurred in the guts of SmCD dsRNA treated worms and that the hemoglobin protein remained intact or mostly intact, retaining its red hue. McKerrow and coworkers [6] reported that degradation cascades of blood protein substrates ingested by schistosomes are substrate-specific, wherein cathepsin D most efficiently produces the primary cleavage of hemoglobin although cysteine proteases provide some redundancy.…”

Section: Discussionmentioning

confidence: 96%

“…We anticipate that the red-colored material in their guts was non-digested hemoglobin. S. mansoni cathepsin D makes the initial cleavage of the hemoglobin monomer, after which other proteases including cathepsins B1, L1, L2 and C and leucine aminopeptidase digest the hemoglobin to short peptides or free amino acids [6,11,25]. In view of the markedly reduced protease activity in extracts of SmCD 1.2 kb-dsRNA treated schistosomules ( Figure 3) and the red-colored gut contents, these findings indicated that the RNAi treatment results in inhibition of hemoglobin proteolysis in cultured schistosomules.…”

Section: Absence Of Accumulation Of Gut Localized Hemozoin Indicativementioning

confidence: 99%

“…Due to its physiological significance for schistosomes, deeper studies on its molecular and biochemical properties, gene structure and phylogeny have been undertaken [6,11,12]. Although cathepsin D-like protease (clan AA) has been involved in digestion of hemoglobin within the adult stages of S. mansoni, it remains unclear whether this enzyme is expressed in and functions in the schistosomula stage early in mammalian infection.…”

Section: Introductionmentioning

confidence: 99%

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RNA interference of Schistosoma mansoni cathepsin D, the apical enzyme of the hemoglobin proteolysis cascade

Morales

Rinaldi

Gobert

et al. 2008

Molecular and Biochemical Parasitology

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118

111

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The aspartic protease cathepsin D (Clan AA, Family A1) is expressed in the schistosome gut where it plays an apical role in the digestion of hemoglobin released from ingested erythrocytes. In this report, RNA interference approaches were employed to investigate the effects of knockdown of schistosome cathepsin D. Cultured schistosomules of Schistosoma mansoni were exposed by square wave electroporation to double stranded RNA (dsRNA) specific for cDNA encoding S. mansoni cathepsin D. RNAi mediated reductions in transcript levels led to phenotypic changes including significant growth retardation in vitro and suppression of aspartic protease enzyme activity. In addition, black-pigmented heme, the end point by-product of normal hemoglobin proteolysis that accumulates in the schistosome gut, was not apparent within the guts of the treated schistosomules. Rather, their guts appeared to be red in color, rather than black, apparently indicating the presence of intact rather than digested host hemoglobin. These phenotypic effects were apparent when either of two forms of dsRNA, a long form spanning the entire target transcript or a short form specific for the 3'-region were employed. Off-target effects were not apparent in transcript levels of the gut-localized cysteine protease cathepsin B1. Finally, cathepsin D may be an essential enzyme in the mammal-parasitic stages of schistosomes because schistosomules treated ex vivo with dsRNA did not survive to maturity after transfer into Balb/c mice. These and earlier findings suggest that, given its essential function in parasite nutrition, schistosome cathepsin D could be developed as a target for novel anti-schistosomal interventions.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 96%

Section: Absence Of Accumulation Of Gut Localized Hemozoin Indicativementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

RNA interference of Schistosoma mansoni cathepsin D, the apical enzyme of the hemoglobin proteolysis cascade

Morales

Rinaldi

Gobert

et al. 2008

Molecular and Biochemical Parasitology

Self Cite

118

111

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“…Aspartic proteases in schistosomes (trematodes) and in H. contortus are involved in the processing of hemoglobin (52,53). Localized in the gut lumen, cross-reaction with polyclonal antisera suggested the presence of aspartic proteases in ESP at a lower concentration compared with gut tissue (53).…”

Section: Variation In and Validation Of Vaccine Candidates Hc15 Hc24mentioning

confidence: 99%

Comprehensive Analysis of the Secreted Proteins of the Parasite Haemonchus contortus Reveals Extensive Sequence Variation and Differential Immune Recognition

Yatsuda

Krijgsveld

Cornelissen

et al. 2003

Journal of Biological Chemistry

192

164

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Haemonchus contortus is a nematode that infects small ruminants. It releases a variety of molecules, designated excretory/secretory products (ESP), into the host. Although the composition of ESP is largely unknown, it is a source of potential vaccine components because ESP are able to induce up to 90% protection in sheep. We used proteomic tools to analyze ESP proteins and determined the recognition of these individual proteins by hyperimmune sera. Following two-dimensional electrophoresis of ESP, matrix-assisted laser desorption ionization time-of-flight and liquid chromatographytandem mass spectrometry were used for protein identification. Few sequences of H. contortus have been determined. Therefore, the data base of expressed sequence tags (dbEST) and a data base consisting of contigs from Haemonchus ESTs were also consulted for identification. Approximately 200 individual spots were observed in the two-dimensional gel. Comprehensive proteomics analysis, combined with bioinformatic search tools, identified 107 proteins in 102 spots. The data include known as well as novel proteins such as serine, metallo-and aspartyl proteases, in addition to H. contortus ESP components like Hc24, Hc40, Hc15, and apical gut GA1 proteins. Novel proteins were identified from matches with H. contortus ESTs displaying high similarity with proteins like cyclophilins, nucleoside diphosphate kinase, OV39 antigen, and undescribed homologues of Caenorhabditis elegans. Of special note is the finding of microsomal peptidase H11, a vaccine candidate previously regarded as a "hidden antigen" because it was not found in ESP. Extensive sequence variation is present in the abundant Hc15 proteins. The Hc15 isoforms are differentially recognized by hyperimmune sera, pointing to a possible specific role of Hc15 in the infectious process and/or in immune evasion. This concept and the identification of multiple novel immune-recognized components in ESP should assist future vaccine development strategies.

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Proteases as Vaccines Against Gastrointestinal Nematode Parasites of Sheep and Cattle

Knox

2012

Parasitic Helminths

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Proteolysis of human hemoglobin by schistosome cathepsin D

Cited by 107 publications

References 31 publications

RNA interference of Schistosoma mansoni cathepsin D, the apical enzyme of the hemoglobin proteolysis cascade

RNA interference of Schistosoma mansoni cathepsin D, the apical enzyme of the hemoglobin proteolysis cascade

Comprehensive Analysis of the Secreted Proteins of the Parasite Haemonchus contortus Reveals Extensive Sequence Variation and Differential Immune Recognition

Proteases as Vaccines Against Gastrointestinal Nematode Parasites of Sheep and Cattle

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