Clonorchis sinensis adult-derived proteins elicit Th2 immune responses by regulating dendritic cells via mannose receptor

Clonorchis sinensis infection amplifies hepatocellular carcinoma stemness, predicting unfavorable prognosis

BACKGROUND

Extensive evidence links Clonorchis sinensis (C. sinensis) to cholangiocarcinoma; however, its association with hepatocellular carcinoma (HCC) is less acknowledged, and the underlying mechanism remains unclear. This study was designed to investigate the association between C. sinensis infection and HCC and reveal the relationship between C. sinensis infection and cancer stemness.

METHODS

A comprehensive analysis of 839 HCC patients categorized into C. sinensis (-) HCC and C. sinensis (+) HCC groups was conducted. Chi-square and Mann-Whitney U tests were used to assess the association between C. sinensis infection and clinical factors. Kaplan-Meier and Cox regression analyses were used to evaluate survival outcomes. Immunohistochemistry was used to determine CK19 and EpCAM expression in HCC specimens.

RESULTS

Compared to C. sinensis (-) HCC patients, C. sinensis (+) HCC patients exhibited advanced Barcelona Clinic Liver Cancer (BCLC) stage, higher male prevalence and more liver cirrhosis as well as elevated alpha-fetoprotein (AFP), carbohydrate antigen 19-9 (CA19-9), eosinophil, complement 3 (C3), and complement 4 (C4) values. C. sinensis infection correlated with shorter overall survival (OS) (p < 0.05) and recurrence-free survival (RFS) (p < 0.05). Furthermore, Cox multivariate analysis revealed that C. sinensis infection was an independent prognostic factor for OS in HCC patients. Importantly, C. sinensis infection upregulated the expression of HCC cancer stem cell markers CK19 and EpCAM.

CONCLUSION

HCC patients with C. sinensis infection exhibit a poor prognosis following hepatectomy. Moreover, C. sinensis infection promotes the acquisition of cancer stem cell-like characteristics, consequently accelerating the malignant progression of HCC.

AUTHOR SUMMARY

Clonorchis sinensis (C. sinensis) is a prominent food-borne parasite prevalent in regions such as China, particularly in Guangxi. C. sinensis has been associated with various hepatobiliary system injuries, encompassing inflammation, periductal fibrosis, cholangiocarcinoma and even hepatocellular carcinoma (HCC). A substantial body of evidence links C. sinensis to cholangiocarcinoma, However, the connection between C. sinensis and HCC and the intricate mechanisms underlying its contribution to HCC development remain incompletely elucidated. Our study demonstrates clear clinicopathological associations between C. sinensis and HCC, such as gender, BCLC stage, liver cirrhosis, MVI, AFP, CA19-9, circulating eosinophils and complements. Furthermore, we found that the co-occurrence of C. sinensis exhibited a significant association with shorter OS and RFS in patients diagnosed with HCC. A major finding was that C. sinensis infection promotes the acquisition of cancer stem cell-like characteristics, consequently accelerating the malignant progression of HCC. Our results provide a more comprehensive comprehension of the interplay between C. sinensis and HCC, shedding fresh light on the carcinogenic potential of C. sinensis.

Coinfection of Clonorchis sinensis and hepatitis B virus: clinical liver indices and interaction in hepatic cell models

BACKGROUND

In China, people infected with hepatitis B virus (HBV) are commonly found in areas with a high prevalence of Clonorchis sinensis, a trematode worm. Published studies have reported that the progression of hepatitis B is affected by coinfection C. sinensis.

METHODS

Clinical data from a total of 72 patients with C. sinensis and HBV (as sole infection or with coinfections) and 29 healthy individuals were analysed. We also incubated the hepatic stellate cell line LX-2 with total proteins from C. sinensis adult worms (CsTPs) and HBV-positive sera. In addition, the human hepatoblastoma cell line HepG2.2.15 was treated with the antiviral drug entecavir (ETV), CsTPs and the anti-C. sinensis drug praziquantel (PZQ).

RESULTS

Our clinical data indicated that the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TB) and hyaluronic acid (HA) were significantly higher in patients with coinfection than in those infected with HBV only. In cell models, compared with the model in which LX-2 cells were incubated with HBV-positive sera (HBV group), transcripts of alpha-smooth muscle actin and types I and III collagen were significantly elevated in the models of LX-2 cells treated with CsTPs and HBV-positive sera (CsTP+HBV group), while the messenger RNA levels of tumour necrosis factor-α, interleukin (IL)-1β and IL-6 in the CsTP+HBV group were clearly lower. The HBV surface antigen and hepatitis B e-antigen levels were higher in the HepG2.2.15 cells treated with ETV and CsTPs than in those in the ETV group and in the cells administered a mixture of ETV, CsTPs and PZQ.

CONCLUSIONS

These results confirmed that C. sinensis and HBV coinfection could aggravate the progression of liver fibrosis. CsTPs might promote chronic inflammation of the liver in individuals with HBV infection, resulting in the development of hepatic fibrosis.

Clonorchis sinensis infection modulates key cytokines for essential immune response impacted by sex

Infection with helminths can modulate the host immune response, which ultimately shape morbidity and mortality of the associated diseases. We studied key cytokines for essential immune response in sera from 229 southeastern China individuals infected with Clonorchis sinensis and 60 individuals without C. sinensis infection, and measured serum specific IgG and IgE against worms in these people. Individuals infected with C. sinensis had significantly higher antigen-specific IgG and IgE levels, which were positively correlated with egg counts in feces. However, less enhancement of IgE antibody was observed in females when compared to males with similar infection levels. C. sinensis infection caused diminished Th1 cytokines (IL-1β, IL-2, IL-12p70, IFN-γ and TNF-α), Th2 cytokine (IL-4), as well as Th17 cytokine (IL-17A) in sera, which showed decreasing trend by infection intensity. Notably, these phenotypes were more significant in females than those in males. Although C. sinensis infection is associated with the development of hepatobiliary diseases, there was no significant correlation between the dampened cytokine profiles and the hepatobiliary morbidities. Our study indicates C. sinensis infection is strongly related to the immune suppression in human. Sex differences shape the immune milieus of clonorchiasis. This study provides a better understanding of how worms affect immune responses and cause a long-term immune alternation in humans with C. sinensis infection.

Cysteine protease of Clonorchis sinensis alleviates DSS-induced colitis in mice

Background

Currently, inflammatory bowel disease (IBD) has become a global chronic idiopathic disease with ever-rising morbidity and prevalence. Accumulating evidence supports the IBD-hygiene hypothesis that helminths and their derivatives have potential therapeutic value for IBD. Clonorchis sinensis (C. sinensis) mainly elicit Th2/Treg-dominated immune responses to maintain long-term parasitism in the host. This study aimed to evaluate the therapeutic effects of cysteine protease (CsCP) and adult crude antigen (CsCA) of C. sinensis, and C. sinensis (Cs) infection on DSS-induced colitis mice.

Methods

BALB/c mice were given 5% DSS daily for 7 days to induce colitis. During this period, mice were treated with rCsCP, CsCA or dexamethasone (DXM) every day, or Cs infection which was established in advance. Changes in body weight, disease activity index (DAI), colon lengths, macroscopic scores, histopathological findings, myeloperoxidase (MPO) activity levels, regulatory T cell (Treg) subset levels, colon gene expression levels, serum cytokine levels, and biochemical indexes were measured.

Results

Compared with Cs infection, rCsCP and CsCA alleviated the disease activity of acute colitis more significant without causing abnormal blood biochemical indexes. In comparison, rCsCP was superior to CsCA in attenuating colonic pathological symptoms, enhancing the proportion of Treg cells in spleens and mesenteric lymph nodes, and improving the secretion of inflammatory-related cytokines (e.g., IL-2, IL-4, IL-10 and IL-13) in serum. Combined with RNA-seq data, it was revealed that CsCA might up-regulate the genes related to C-type lectin receptor and intestinal mucosal repair related signal pathways (e.g., Cd209d, F13a1 and Cckbr) to reduce colon inflammation and benefit intestinal mucosal repair. Dissimilarly, rCsCP ameliorated colitis mainly through stimulating innate immunity, such as Toll like receptor (TLR) signaling pathway, down-regulating the expression of inflammatory cytokines (e.g., IL-12b, IL-23r and IL-7), thereby restraining the differentiation of Th1/Th17 cells.

Conclusions

Both rCsCP and CsCA showed good therapeutic effects on the treatment of acute colitis, but rCsCP is a better choice. rCsCP is a safe, effective, readily available and promising therapeutic agent against IBD mainly by activating innate immunity and regulating the IL-12/IL-23r axis.

Molecular Mechanisms of Clonorchis sinensis-Host Interactions and Implications for Vaccine Development

Infections caused by Clonorchis sinensis remain a significant public health challenge for both humans and animals, causing pyogenic cholangitis, cholelithiasis, cholecystitis, biliary fibrosis, and even cholangiocarcinoma. However, the strategies used by the parasite and the immunological mechanisms used by the host have not yet been fully understood. With the advances in technologies and the accumulated knowledge of host-parasite interactions, many vaccine candidates against liver flukes have been investigated using different strategies. In this review, we explore and analyze in-depth the immunological mechanisms involved in the pathogenicity of C. sinensis. We highlight the different mechanisms by which the parasite interacts with its host to induce immune responses. All together, these data will allow us to have a better understanding of molecular mechansism of host-parasite interactions, which may shed lights on the development of an effective vaccine against C. sinensis.

Autophagy of hepatic stellate cell induced by Clonorchis sinensis

BACKGROUND

Clonorchis sinensis was a food-borne zoonotic parasite in the worldwide and also an important risk factor of hepatic fibrosis. Excretory/secretion products of C. sinensis (CsESPs) are involved in parasite-host interactions and contribute to the development of hepatic damage. The aim of the present study was to investigate whether CsESPs and CsTP (adult protein) could induce autophagy of hepatic stellate cells (HSCs) and further activate HSCs so as to participate in the pathogenesis of hepatic fibrosis.

METHODS AND RESULTS

The human hepatic stellate cell line LX-2 was stimulated by CsESPs and CsTP. CsESPs showed the effect on cell proliferation in methyl thiazolyl tetrazolium (MTT) assay while CsTP failed. Autophagosomes and autolysosomes were observed after the transmission mRFP-EGFP-LC3 plasmid into the LX-2 cells. CsESPs had more powerful to induce the accumulation of autophagosomes and autolysosomes to enhance autophagic flux compared with CsTP. Western-blotting analysis confirmed that the ratio of LC3-II/I in LX-2 cells was up-regulated after CsESPs treatment for 6 h, which further proved that CsESPs could induce autophagy in LX-2 cells. Meanwhile, q-PCR results showed that the mRNA levels of collagen I, collagen III and α-SMA decreased in LX-2 cells after treatment with autophagy inhibitor chloroquine, whereas they increased when combination with CsESPs.

CONCLUSIONS

These results suggested that CsESPs-induced autophagy might be involved in the activation of HSCs, and consequently participate in the pathogenesis of hepatic fibrosis caused by C. sinensis infection.

The dynamics of select cellular responses and cytokine expression profiles in mice infected with juvenile Clonorchis sinensis

Clonorchiasis is a zoonotic disease that can result in chronic infection in humans. The causative agent, Clonorchis sinensis (C. sinensis), is believed to primarily induce a Th2 immune response in infected mice. However, few studies have profiled host immune responses to C. sinensis infection during the juvenile phase. In the present study, the dynamics of select cellular responses and cytokine expression profiles during juvenile C. sinensis infection were investigated. The flow cytometry results showed that the CD4+ T cells percentage was significantly decreased between 12 days post-infection (dpi) and 24 dpi in the peripheral blood, and the CD8+ T cells percentage was significantly elevated after 3 dpi. The ratio of CD4+/CD8+ T cells was also significantly decreased after 3 dpi. Furthermore, we observed that the proportion of CD14+ monocyte-macrophages in the peripheral blood was significantly increased between 1 dpi and 12 dpi and peaked at 6 dpi. The percentage of classically activated macrophages (M1) and alternatively activated macrophages (M2) in the liver was significantly increased between 18 dpi and 30 dpi. qRT-PCR results showed that the expression levels of iNOS in the liver were significantly elevated after 3 dpi, and Arg-1 expression was significantly increased beginning at 12 dpi. ELISA results showed that the serum levels of the Th1 cytokines IFN-γ and IL-2 peaked at 6 dpi and decreased thereafter. Furthermore, the Th2 cytokines IL-4 and IL-13 began to be expressed and peaked at 24 dpi and 30 dpi, respectively. In addition, the levels of the Treg cytokines IL-10 and TGF-β₁ were significantly increased beginning at 6 dpi until 30 dpi. In the liver homogenate, the expression of IFN-γ, IL-2, and IL-4 mainly occurred before 6 dpi. IL-13 expression was significantly increased at 30 dpi. IL-10 and TGF-β₁ levels were significantly increased at 12 dpi and 24 dpi, and expression peaked at 24 dpi and 30 dpi, respectively. This study provides a fundamental characterization for the future analysis of host-parasite interactions and immune responses in hosts infected with juvenile C. sinensis.

The NF-κB signalling pathway and TM7SF3 contribute to liver fibrosis caused by secreted phospholipase A2 of Clonorchis sinensis

Background

The NF-κB signalling pathway has been reported to be related to liver fibrosis, and we investigated whether the NF-κB signalling pathway is involved in liver fibrosis caused by secreted phospholipase A2 of Clonorchis sinensis (CssPLA2). Furthermore, expression of the receptor of CssPLA2 on the cell surface of hepatic stellate cells (HSCs) may greatly contribute to liver fibrosis.

Methods

CssPLA2 was administered to BALB/c mice by abdominal injection. The levels of markers of NF-κB signalling pathway activation in mouse liver tissue were measured by quantitative RT-PCR, ELISA and western blot. Additionally, HSCs were incubated with CssPLA2, and an NF-κB signalling inhibitor (BAY 11-7082) was applied to test whether the NF-κB signalling pathway plays a role in the effect of CssPLA2. Then, the interaction between CssPLA2 and its receptor transmembrane 7 superfamily member 3 (TM7SF3) was confirmed by co-immunoprecipitation (co-IP) and GST pull-down. To determine how TM7SF3 influences the ability of CssPLA2 to cause liver fibrosis, a TM7SF3 antibody was used to block TM7SF3.

Results

The levels of the NF-ΚB signalling pathway activation markers TNF-α, IL-1β and phospho-p65 were increased by CssPLA2 in the context of liver fibrosis. In addition, the interaction between TM7SF3 and CssPLA2 was confirmed by co-IP and GST pull-down. When TM7SF3 was blocked by an antibody targeting 1–295 amino acids of TM7SF3, activation of HSCs caused by CssPLA2 was alleviated.

Conclusions

The NF-ΚB signalling pathway is involved in the activation of HSCs by CssPLA2. TM7SF3, the receptor of CssPLA2, plays important roles in liver fibrosis caused by CssPLA2.

Recombinant CsHscB of carcinogenic liver fluke Clonorchis sinensis induces IL-10 production by binding with TLR2

BACKGROUND

Clonorchis sinensis, a fluke dwelling in the intrahepatic bile ducts causes clonorchiasis, which affect about 15 million people wide-distributed in eastern Asia. During C. sinensis infection, worm-host interaction results in activation of patterns recognition receptors (PRRs) such as Toll-like receptors (TLRs) and further triggers immune responses, which determines the outcome of the infection. However, the mechanisms by which pathogen-associated molecules patterns from C. sinensis interact with TLRs were poorly understood. In the present study, we assumed that the molecules from C. sinensis may regulate host immune responses via TLR2 signaling pathway.

METHODOLOGY/PRINCIPAL FINDINGS

In the present study, we have identified a ~34 kDa CsHscB from C. sinensis which physically bound with TLR2 as demonstrated by molecular docking and pull-down assay. We also found that recombinant CsHscB (rCsHscB) potently activates macrophage to express various proteins including TLR2, CD80, MHCII, and cytokines like IL-6, TNF-α, and IL-10, but rCsHscB failed to induce IL-10 in macrophages from Tlr2-/- mice. Moreover, ERK1/2 activation was required for rCsHscB-induced IL-10 production in macrophages. In vivo study revealed that rCsHscB triggered a high production of IL-10 in the wild-type (WT) but not in Tlr2-/- mice. Consistently, the phosphorylation of ERK1/2 was also attenuated in Tlr2-/- mice compared to the WT mice, after the treatment with rCsHscB.

CONCLUSIONS/SIGNIFICANCE

Our data thus demonstrate that rCsHscB from C. sinensis interacts with TLR2 to be endowed with immune regulatory activities, and may have some therapeutic implications in future beyond parasitology.

In vivo and in vitro studies using Clonorchis sinensis adult-derived total protein (CsTP) on cellular function and inflammatory effect in mouse and cell model

Clonorchis sinensis (C. sinensis) can induce a food-borne parasitic disease (clonorchiasis). Numerous studies have analyzed functional proteins, immunologic factors, pro-inflammatory cytokines, and cell signaling transduction that promote the development of clonorchiasis. In a previous study, it was shown that C. sinensis adult-derived total protein (CsTP) might be involved in the pathogenesis and development of liver fibrosis via bringing about Th2 immune response. In the present study, further investigation of CsTP on cellular function and inflammatory effect in vitro and in vivo has been elicited. CsTP induced inflammation and autophagy as evidenced by upregulation of TNF-α, IFN-γ, and autophagic markers LC3B and P62. Exposed to CsTP upregulated the antiapoptotic gene Bcl-2 expression, diminished the apoptosis induced by H₂O₂, but promoted the proliferation and migration of LX-2 cells in proper concentration range. Additionally, the protein levels of p-AKT and p-mTOR were repressed in response to CsTP, suggesting a correlation of blocking the activation of mTOR/AKT signaling pathway. These results revealed that CsTP might exacerbate hepatic pathological changes by regulating cell proliferation, apoptosis, autophagy, and inflammation in the liver and LX-2 cells. Some effects might be partially involved in the mTOR and AKT pathways.

Membrane-bound IgE on B cells is increased during Clonorchis sinensis infection

A high level of serum IgE is a hallmark of helminthic disease. Secretory IgE can bind FcεRI or FcεRII/CD23. The combination of IgE and FcεRI, a high-affinity interaction, has long received attention and is believed to facilitate helminth control, while the properties of CD23-bound IgE have long been unexplored. Here, we established a Clonorchis sinensis (C. sinensis) infection model with different mouse strains and investigated membrane-bound IgE on B cells during infection. We show that after infection, the increase in CD23 expression on B cells was obvious, even in relatively resistant C57BL/6 mice, as well as in susceptible BALB/c and FVB mice. Although the serum IgE amount was lower in C57BL/6 mice than in BALB/c and FVB mice, the level of IgE binding to peripheral B cells was also elevated. Additionally, the IgE on B cells was soon undetectable in vitro due to dissociable binding. The results of the present study demonstrate the dramatic increase in CD23-bound IgE on B cells after C. sinensis infection. The significance of CD23-bound IgE in Ag transport and presentation has gained consideration in allergy development for its potential ability to promote the Th2 response. Therefore, even though the association of IgE and CD23 is not as substantial as that of IgE and FcεRI, membrane-bound IgE on B cells may be worth further study regarding clonorchiasis and other parasitic infections.