Advanced enzymology, expression profile and immune response of Clonorchis sinensis hexokinase show its application potential for prevention and control of clonorchiasis

ASPSCR-1 and Sirt-5 alleviate Clonorchis liver fluke rCsNOSIP-induced oxidative stress, proliferation, and migration in cholangiocarcinoma cells

BACKGROUND

Clonorchiasis, caused by the infection of Clonorchis sinensis (C. sinensis), is a kind of neglected tropical disease, but it is highly related to cholangiocarcinoma. It has been well known that NO from chronic inflammation responses are thought to be a major component of the damage and ultimate carcinogenesis ESPs such as nitric oxide synthase interacting protein (NOSIP) are thought to enhance the damage. The objective of this study was to identify the protein candidates interact with recombinant CsNOSIP (rCsNOSIP) and explore their role involved in CCA development or progression.

METHODS

We applied HuProt microarray containing 21,000 probe sets for a systematic identification of rCsNOSIP-binding proteins and grouped binding hits by gene function. Pull-down assays were used to confirm the interaction of rCsNOSIP with alveolar soft part sarcoma (ASPSCR-1) and sirtuins 5 (Sirt-5). ASPSCR-1/Sirt-5 over-expression and siRNA knockdown experiments were employed for obtain of ASPSCR-1/Sirt-5 high or low expression (ASP-oe/Sirt5-oe or ASP-si/Sirt5-si) cholangiocarcinoma cell line (CCLP-1) cells. Nitric oxide (NO) and reactive oxygen species assay (ROS) as well as cell proliferation and wound-healing assays were performed to observe the effect of rCsNOSIP on ASP-oe/Sirt5-oe or ASP-si/Sirt5-si CCLP-1 cells.

RESULTS

Seventy candidate proteins protein "hits" were detected as rCsNOSIP-binding proteins by HuProt microarray and bioinformatics analysis. Pull down assay showed that ASPSCR-1 and Sirt-5 could interact with rCsNOSIP. In addition, endotoxin-free-rCsNOSIP could increase the production of NO and ROS and promote the migration of CCLP-1 cells, while its effect on enhancing cell proliferation was not significant. Furthermore, ROS/NO production, proliferation, or migration were increased in ASP-si or Sirt5-si CCLP-1 cells but decreased in Asp-oe or Sirt5-oe CCLP-1 cells when stimulated with rCsNOSIP.

CONCLUSIONS

Our findings suggest that CsNOSIP as a component of CsESPs might promote the development and invasion of CCA and Sirt5/ ASPSCR1 as host molecules might play a novel protective role against adverse stimulus during C. sinensis infection. This work supports the idea that CsESPs induce the occurrence and progression of CCA through ROS/RNS-induced oxidative and nitrative DNA damage.

Molecular characterization of hexokinase (HK) in Haemaphysalis longicornis and evaluation of HK protein- and DNA-based vaccines against adult ticks

BACKGROUND

Haemaphysalis longicornis is an obligate hematophagous ectoparasite, which transmits various pathogens to humans, livestock and wild animals. Hexokinase (HK) is a key regulatory enzyme of the glycolytic pathway in the organisms. However, little is known about hexokinase and its functions in ticks.

RESULTS

The open reading frame of the H. longicornis HK (HlHK) gene was 1425 bp and encoded a protein of 474 amino acids, containing conserved domains for glucose, glucose 6-phosphate, and adenosine triphosphate. The expression of HlHK gene was detected at different developmental stages and in different tissues of unfed female ticks. Enzyme-linked immunosorbent assay revealed that both HK protein- and DNA-based vaccines increased the antibody levels of the immunized animals. A vaccination trail on rabbits against H. longicornis infestation indicated that the rHlHK protein and HlHK DNA vaccines reduced the number of attached female ticks by 9% and 12%, egg mass weight by 36% and 34%, and egg hatching rate by 41% and 17%, respectively. Overall, protein vaccination conferred 65.6% protection against adult female ticks, whereas the DNA vaccine conferred 51.8% protection.

CONCLUSION

This is the first report of the molecular characterization of the HK protein and sequencing of the HK gene from H. longicornis. Positive results from vaccination trials on rabbits of the recombinant HK protein and HK DNA suggest that these novel anti-tick vaccines potentially can be used as viable tick control tools for the management of the Asian longhorned tick. Additionally, inhibition of glucose metabolism may be a new strategy for tick control. © 2023 Society of Chemical Industry.

Molecular characterization and serodiagnostic potential of Echinococcus granulosus hexokinase

Background

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus (sensu stricto), is a life-threatening but neglected zoonosis. Glycolytic enzymes are crucial molecules for the survival and development of E. granulosus. The aim of this study was to investigate the molecular characterization, immunogenicity, tissue distribution and serodiagnostic potential of E. granulosus hexokinase (EgHK), the first key enzyme in the glycolytic pathway.

Methods

EgHK was cloned and expressed in Escherichia coli. Specific serum antibodies were evaluated in mice immunized with recombinant EgHK (rEgHK). The location of EgHK in the larval stage of E. granulosus was determined using fluorescence immunohistochemistry, and the potential of rEgHK as a diagnostic antigen was investigated in patients with CE using indirect enzyme-linked immunosorbent assay (ELISA).

Results

Recombinant EgHK could be identified in the sera of patients with CE and in mouse anti-rEgHK sera. High titers of specific immunoglobulin G were induced in mice after immunization with rEgHK. EgHK was mainly located in the tegument, suckers and hooklets of protoscoleces and in the germinal layer and laminated layer of the cyst wall. The sensitivity and specificity of the rEgHK-ELISA reached 91.3% (42/46) and 87.8% (43/49), respectively.

Conclusions

We have characterized the sequence, structure and location of EgHK and investigated the immunoreactivity, immunogenicity and serodiagnostic potential of rEgHK. Our results suggest that EgHK may be a promising candidate for the development of vaccines against E. granulosus and an effective antigen for the diagnosis of human CE.

Carbohydrate Kinases: A Conserved Mechanism Across Differing Folds

Carbohydrate kinases activate a wide variety of monosaccharides by adding a phosphate group, usually from ATP. This modification is fundamental to saccharide utilization, and it is likely a very ancient reaction. Modern organisms contain carbohydrate kinases from at least five main protein families. These range from the highly specialized inositol kinases, to the ribokinases and galactokinases, which belong to families that phosphorylate a wide range of substrates. The carbohydrate kinases utilize a common strategy to drive the reaction between the sugar hydroxyl and the donor phosphate. Each sugar is held in position by a network of hydrogen bonds to the non-reactive hydroxyls (and other functional groups). The reactive hydroxyl is deprotonated, usually by an aspartic acid side chain acting as a catalytic base. The deprotonated hydroxyl then attacks the donor phosphate. The resulting pentacoordinate transition state is stabilized by an adjacent divalent cation, and sometimes by a positively charged protein side chain or the presence of an anion hole. Many carbohydrate kinases are allosterically regulated using a wide variety of strategies, due to their roles at critical control points in carbohydrate metabolism. The evolution of a similar mechanism in several folds highlights the elegance and simplicity of the catalytic scheme.

Modeling the Transmission Dynamics of Clonorchiasis in Foshan, China

Clonorchiasis, known as the Chinese liver fluke disease, is caused by Clonorchis sinensis infection with food-borne liver fluke, which is transmitted via snails to freshwater fish and then to human beings or other piscivorous mammals. Clonorchis sinensis infection is mainly related to liver and biliary disorders, especially cholangiocarcinoma, and has an increased human-health impact due to the greater consumption of raw freshwater fish. In this article, we propose a deterministic model to describe the spread of clonorchiasis among human-snail-fish populations and use the model to simulate the data on the numbers of inspected and infected individuals of Foshan City, located in Guangdong Province in the southeast of P.R China, from 1980-2010. Mathematical and numerical analyses of the model are carried out to understand the transmission dynamics of clonorchiasis and explore effective control measures for the local outbreaks of the disease. We find that (i) the transmission of clonorchiasis from cercariae to fish plays a more important role than that from eggs to snails and from fish to humans; (ii) As the cycle of infection-treatment-reinfection continues, it is unlikely that treatment with drugs alone can control and eventually eradicate clonorchiasis. These strongly suggest that a more comprehensive approach needs to include environmental modification in order to break the cercariae-fish transmission cycle, to enhance awareness about the disease, and to improve prevention measures.

Structural Analysis of an Epitope Candidate of Triosephosphate Isomerase in Opisthorchis viverrini

Opisthorchis viverrini, a parasitic trematode, was recategorized as a group 1 biological carcinogen because it causes opisthorchiasis, which may result in cholangiocarcinoma. A new strategy for controlling opisthorchiasis is needed because of issues such as drug resistance and reinfection. Triosephosphate isomerase (TIM), a key enzyme in energy metabolism, is regarded as a potential drug target and vaccine candidate against various pathogens. Here, we determined the crystal structures of wild-type and 3 variants of TIMs from O. viverrini (OvTIM) at high resolution. The unique tripeptide of parasite trematodes, the SAD motif, was located on the surface of OvTIM and contributed to forming a 3₁₀-helix of the following loop in a sequence-independent manner. Through thermal stability and structural analyses of OvTIM variants, we found that the SAD motif induced local structural alterations of the surface and was involved in the overall stability of OvTIM in a complementary manner with another parasite-specific residue, N115. Comparison of the surface characteristics between OvTIM and Homo sapiens TIM (HsTIM) and structure-based epitope prediction suggested that the SAD motif functions as an epitope.

A 21.6 kDa tegumental protein of Clonorchis sinensis induces a Th1/Th2 mixed immune response in mice

Introduction

Clonorchis sinensis is a major parasite affecting the Korea population. Despite the high infection rate and pathogenicity, very few studies have been conducted to investigate the immune responses against the proteins of C. sinensis.

Methods

In this study, in vitro immune response induced by a recombinant 21.6 kDa tegumental protein derived from C. sinensis (rCsTegu21.6) was confirmed in murine dendritic cells and T cells. For the in vivo analysis, each mouse was immunized three times. Total serum IgG and T cell cytokine production were determined by ELISA, while T cell proliferation was detected by a WST (Water‐Soluble Tetrazolium salt)‐1 assay.

Results

In vitro tests indicated that rCsTegu21.6 treatment increased the expression of surface molecules, such as CD40 (77%), CD80 (52%) and CD86 (46%), on murine dendritic cells and the secretion of cytokines (TNF‐α, IL‐6, IL‐1β, IL‐10, and IL‐12p70). Moreover, co‐culturing dendritic cells activated by rCsTegu21.6 with allogenic T cells induced T cell proliferation over time. rCsTegu21.6 also stimulated specific antibody production and cytokine secretion [IL‐2, IL‐4, and interferon (IFN)‐γ)] from T cells following immunization in vivo. Notably, rCsTegu21.6 predominantly induced IgG1 production and secretion of the Th2 cytokine IL‐4, regardless of the type of adjuvant used.

Conclusion

These results serve as a foundation for the development of tegumental protein‐based vaccines against C. sinensis.

Virus-like particles vaccine containing Clonorchis sinensis tegumental protein induces partial protection against Clonorchis sinensis infection

Background

Human clonorchiasis, caused by the infection of Clonorchis sinensis, is one of the major health problems in Southeast Asia. However, vaccine efficacy against C. sinensis infection remains largely unknown.

Methods

In this study, for the first time, we generated virus-like particles (VLPs) vaccine containing the C. sinensis tegumental protein 22.3 kDa (CsTP 22.3) and the influenza matrix protein (M1) as a core protein, and investigated the vaccine efficacy in Sprague-Dawley rats.

Results

Intranasal immunization of VLPs vaccine induced C. sinensis-specific IgG, IgG2a and IgG2c in the sera and IgA responses in the feces and intestines. Notably, upon challenge infection with C. sinensis metacercariae, significantly lower adult worm loads (70.2%) were measured in the liver of rats immunized with VLPs, compared to those of naïve rats. Furthermore, VLPs immunization induced antibody secreting cells (ASC) responses and CD4+/CD8+ T cell responses in the spleen.

Conclusions

Our results indicated that VLPs vaccine containing C. sinensis CsTP 22.3 kDa provided partial protection against C. sisnensis infection. Thus, VLPs could be a potential vaccine candidate against C. sinensis.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2526-5) contains supplementary material, which is available to authorized users.

Sequence analysis and characterization of pyruvate kinase from Clonorchis sinensis, a 53.1-kDa homopentamer, implicated immune protective efficacy against clonorchiasis

BACKGROUND

Clonorchis sinensis, the causative agent of clonorchiasis, is classified as one of the most neglected tropical diseases and affects more than 15 million people globally. This hepatobiliary disease is highly associated with cholangiocarcinoma. As key molecules in the infectivity and subsistence of trematodes, glycolytic enzymes have been targets for drug and vaccine development. Clonorchis sinensis pyruvate kinase (CsPK), a crucial glycolytic enzyme, was characterized in this research.

RESULTS

Differences were observed in the sequences and spatial structures of CsPK and PKs from humans, rats, mice and rabbits. CsPK possessed a characteristic active site signature (IKLIAKIENHEGV) and some unique sites but lacked the N-terminal domain. The predicted subunit molecular mass (Mr) of CsPK was 53.1 kDa. Recombinant CsPK (rCsPK) was a homopentamer with a Mr. of approximately 290 kDa by both native PAGE and gel filtration chromatography. Significant differences in the protein and mRNA levels of CsPK were observed among four life stages of C. sinensis (egg, adult worm, excysted metacercaria and metacercaria), suggesting that these developmental stages may be associated with diverse energy demands. CsPK was widely distributed in adult worms. Moreover, an intense Th1-biased immune response was persistently elicited in rats immunized with rCsPK. Also, rat anti-rCsPK sera suppressed C. sinensis adult subsistence both in vivo and in vitro.

CONCLUSIONS

The sequences and spatial structures, molecular mass, and expression profile of CsPK have been characterized. rCsPK was indicated to be a homopentamer. Rat anti-rCsPK sera suppressed C. sinensis adult subsistence both in vivo and in vitro. CsPK is worthy of further study as a promising target for drug and vaccine development.

Current status and perspectives of Clonorchis sinensis and clonorchiasis: epidemiology, pathogenesis, omics, prevention and control

Clonorchiasis, caused by Clonorchis sinensis (C. sinensis), is an important food-borne parasitic disease and one of the most common zoonoses. Currently, it is estimated that more than 200 million people are at risk of C. sinensis infection, and over 15 million are infected worldwide. C. sinensis infection is closely related to cholangiocarcinoma (CCA), fibrosis and other human hepatobiliary diseases; thus, clonorchiasis is a serious public health problem in endemic areas. This article reviews the current knowledge regarding the epidemiology, disease burden and treatment of clonorchiasis as well as summarizes the techniques for detecting C. sinensis infection in humans and intermediate hosts and vaccine development against clonorchiasis. Newer data regarding the pathogenesis of clonorchiasis and the genome, transcriptome and secretome of C. sinensis are collected, thus providing perspectives for future studies. These advances in research will aid the development of innovative strategies for the prevention and control of clonorchiasis.