title: Identification and characterization of Clonorchis sinensis cathepsin B proteases in the pathogenesis of clonorchiasis.
abstract: BACKGROUND
  Human clonorchiasis is a prevailing food-borne disease caused by Clonorchis sinensis infection. Functional characterizations of key molecules from C. sinensis could facilitate the intervention of C. sinensis associated diseases.
  
  
  METHODS
  In this study, immunolocalization of C. sinensis cathepsin B proteases (CsCBs) in C. sinensis worms was investigated. Four CsCBs were expressed in Pichia pastoris yeast cells. Purified yCsCBs were measured for enzymatic and hydrolase activities in the presence of various host proteins. Cell proliferation, wound-healing and transwell assays were performed to show the effect of CsCBs on human cells.
  
  
  RESULTS
  CsCBs were localized in the excretory vesicle, oral sucker and intestinal tract of C. sinensis. Recombinant yCsCBs from yeast showed active enzymatic activity at pH 5.0-5.5 and at 37-42 °C. yCsCBs can degrade various host proteins including human serum albumin, human fibronectin, human hemoglobin and human IgG. CsCBs were detected in liver tissues of mice and cancer patients afflicted with clonorchiasis. Various bioassays collectively demonstrated that CsCBs could promote cell proliferation, migration and invasion of human cancer cells.
  
  
  CONCLUSIONS
  Our results demonstrated that CsCBs can degrade various human proteins and we proved that the secreted CsCBs are involved in the pathogenesis of clonorchiasis.
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. fannie_1985@hotmail.com.|Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. fannie_1985@hotmail.com.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. 364574522@qq.com.|Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. 364574522@qq.com.|Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, Guangdong, 511430, China. 364574522@qq.com.
authors.forename: Dan
authors.initials: D
authors.lastname: Ning
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. xwang13@uchicago.edu.|Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. xwang13@uchicago.edu.
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. 710387301@qq.com.|Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. 710387301@qq.com.
authors.forename: Tingjin
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Medical Laboratory and Research Center, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710038, China. 510099864@qq.com.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Lv
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, Guangdong, 511430, China. 395252689@qq.com.
authors.forename: Jiufeng
authors.initials: J
authors.lastname: Sun
authors.affiliation: Guangdong Provincial Institute of Public Health, Guangdong Provincial Center for Disease Control and Prevention, Guangzhou, Guangdong, 511430, China. 445831343@qq.com.
authors.forename: De
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. huang66@mail.sysu.edu.cn.|Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. huang66@mail.sysu.edu.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. xujinteam@163.com.|Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. xujinteam@163.com.
authors.forename: Jin
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. yuhxteam@163.com.|Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, 510080, People's Republic of China. yuhxteam@163.com.
authors.forename: Xinbing
authors.initials: X
authors.lastname: Yu
mesh_terms: D000818:Animals; D002401:Cathepsin B / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D049109:Cell Proliferation; D003001:Cloning, Molecular; D003003:Clonorchiasis / Q000469:parasitology*; D003004:Clonorchis sinensis / Q000201:enzymology* / Q000472:pathogenicity*; D004195:Disease Models, Animal; D004795:Enzyme Stability; D015870:Gene Expression; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008099:Liver / Q000473:pathology; D051379:Mice; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D059748:Proteolysis; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013696:Temperature; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D011994:Recombinant Proteins; D037521:Virulence Factors; D002401:Cathepsin B