title: Molecular expression and enzymatic characterization of thioredoxin from the carcinogenic human liver fluke Opisthorchis viverrini.
abstract: The human liver fluke, Opisthorchis viverrini, induces inflammation of the hepatobiliary system. Despite being constantly exposed to inimical oxygen radicals released from inflammatory cells, the parasite survives for years. Defense against oxidative damage can be mediated through glutathione and/or thioredoxin utilizing systems. Here, we report the molecular expression and biochemical characterization of a thioredoxin (Trx) from O. viverrini. O. viverrini Trx cDNA encoded a polypeptide of 105 amino acid residues, of molecular mass 11.63 kDa. The predicted protein has similarity to previously characterized thioredoxins with 26-51% identity. Recombinant O. viverrini Trx (Ov-Trx-1) was expressed as soluble protein in E. coli. The recombinant protein showed insulin reduction activity and supported the enzymatic function of O. viverrini thioredoxin peroxidase. Expression of Ov-Trx-1 at mRNA and protein levels was observed in all obtainable developmental stages of the liver fluke. Ov-Trx-1 was also detected in excretory-secretory products released by adult O. viverrini. Immunohistochemistry, Ov-Trx-1 was expressed in nearly all parasite tissue excepted ovary and mature sperms. Interestingly, Ov-Trx-1 was observed in the infected biliary epithelium but not in normal bile ducts. These results suggest that Ov-Trx-1 is essential for the parasite throughout the life cycle. In the host-parasite interaction aspect, Ov-Trx-1 may support thioredoxin peroxidase in protecting the parasite against damage induced by reactive oxygen species from inflammation.
authors: Graduate School, Khon Kaen University, Khon Kaen 40002, Thailand.
authors: Sutas
authors: S
authors: Suttiprapa
authors: Pitchaya
authors: P
authors: Matchimakul
authors: Alex
authors: A
authors: Loukas
authors: Thewarach
authors: T
authors: Laha
authors: Sopit
authors: S
authors: Wongkham
authors: Sasithorn
authors: S
authors: Kaewkes
authors: Paul J
authors: PJ
authors: Brindley
authors: Banchob
authors: B
authors: Sripa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001653:Bile Ducts, Intrahepatic / Q000378:metabolism / Q000469:parasitology; D015153:Blotting, Western; D058487:Cercaria / Q000737:chemistry / Q000254:growth & development; D002846:Chromatography, Affinity; D018076:DNA, Complementary / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D020869:Gene Expression Profiling; D015801:Helminth Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D009889:Opisthorchiasis / Q000201:enzymology / Q000235:genetics; D009891:Opisthorchis / Q000737:chemistry / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D010063:Ovum / Q000737:chemistry / Q000254:growth & development; D054464:Peroxiredoxins / Q000235:genetics*; D010802:Phylogeny; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D013785:Thailand; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D015801:Helminth Proteins; D011994:Recombinant Proteins; D013879:Thioredoxins; D054464:Peroxiredoxins