ABSTRACT
BACKGROUND: Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is increasing worldwide. Although there is currently no completely curative treatment, helminthic therapy shows certain therapeutic potential for UC. Many studies have found that Trichinella spiralis (T.s) has a protective effect on UC, but the specific mechanism is still unclear. METHODS: Balb/c mice drank dextran sulfate sodium (DSS) to induce acute colitis and then were treated with T.s. In vitro experiments, the LPS combination with ATP was used to induce the pyroptosis model, followed by intervention with crude protein from T.s (T.s cp). Additionally, the pyroptosis agonist of NSC or the pyroptosis inhibitor vx-765 was added to intervene to explore the role of pyroptosis in DSS-induced acute colitis. The degree of pyroptosis was evaluated by western blot, qPCR and IHC, etc., in vivo and in vitro. RESULTS: T.s intervention significantly inhibited NLRP3 inflammasome activation and GSDMD-mediated pyroptosis by downregulating the expression of pyroptosis-related signatures in vitro (cellular inflammatory model) and in vivo (DSS-induced UC mice model). Furthermore, blockade of GSDMD-mediated pyroptosis by the caspase-1 inhibitor vx-765 has a similar therapeutic effect on DSS-induced UC mice with T.s intervention, thus indicating that T.s intervention alleviated DSS-induced UC in mice by inhibiting GSDMD-mediated pyroptosis. CONCLUSION: This study showed that T.s could alleviate the pathological severity UC via GSDMD-mediated pyroptosis, and it provides new insight into the mechanistic study and application of helminths in treating colitis.
Subject(s)
Colitis, Ulcerative , Colitis , Gasdermins , Inflammatory Bowel Diseases , Trichinella spiralis , Animals , Mice , Colitis/chemically induced , Colitis, Ulcerative/chemically induced , Colitis, Ulcerative/drug therapy , Dextran Sulfate/toxicity , Disease Models, Animal , Mice, Inbred C57BL , PyroptosisABSTRACT
The pathogenesis of chronic schistosomiasis is caused by irritation of the schistosome eggs trapped in liver that induce delayed hypersensitive reactions from the surrounding tissues, leading to the formation of inflammatory granuloma and subsequent fibrosis. A Schistosoma japonicum (S. japonicum) single-chain fragment variable (SjscFv) which specifically binds to the S. japonicum soluble immature egg antigen (SIEA) can be used as a target to deliver specific cytokine towards the site of hepatic fibrosis. To test this hypothesis, a novel recombinant plasmid, pVAX1/SjscFv-IL18, was constructed by fusing SjscFv to IL-18 gene with a 45bp glycine-rich linker. Furthermore, experiments on mice showed that pVAX1/SjscFv-IL18 could effectively express IL-18 in the liver and in serum. Hepatic contents of IL-2 and IFN-γ (Th1-type) in S. japonicum-infected mice vaccinated with pVAX1/SjscFv-IL18 increased significantly but those of their IL-4 and IL-10 (Th2-type) decreased as compared to the analyzed results of 4 cytokines in the liver cells of control mice vccinated with pVAX1/IL18. Consistent with the levels of Th1 and Th2 cytokines, mice vaccinated with pVAX1/SjscFv-IL18 developed much less hepatic fibrosis 20weeks after infection, which was evaluated by average volumn of granuloma and collagen contents. These data suggested that the linkage of IL-18 to the target-specific SjscFv molecule appears to be a potentially promising trial route of therapy, the hepatic fibrosis in S. japonicum-infected mice may be ameliorated through effective expression of IL18 in liver.
Subject(s)
Interleukin-18/genetics , Liver Cirrhosis/prevention & control , Liver/metabolism , Schistosoma japonicum/genetics , Schistosomiasis japonica/complications , Single-Chain Antibodies/genetics , Animals , DNA, Helminth/administration & dosage , Female , Interleukin-18/immunology , Interleukin-18/metabolism , Liver/immunology , Liver/parasitology , Liver Cirrhosis/parasitology , Mice , Mice, Inbred BALB C , Plasmids , Random Allocation , Schistosoma japonicum/immunology , Schistosomiasis japonica/immunology , Single-Chain Antibodies/immunology , Single-Chain Antibodies/metabolismABSTRACT
OBJECTIVE: To clone the full-length gene encoding succinate dehydrogenase iron-sulfur protein of Schistosoma japonicum (SjSDISP) Chinese strain and express it in Escherichia coli. METHODS: According to the published incomplete EST (BU804141) of SjSDISP and the sequence of multiclone sites of lambda gt11 vector, 2 pairs of primers were designed and synthesized. Then the 3' and 5'ends of the EST of the SjSDISP from adult Schistosoma japonicum cDNA library were amplified by anchored PCR. After sequencing, a full-length cDNA sequence of the SjSDISP was obtained, and then it was cloned into prokaryotic expression vector pGEX-4T-1. Identified by agarosed gel electrophoresis, endonucleases digestion and PCR, the resultant recombinant plasmid was used for the expression under the temperature-dependent condition and Western blot analysis. RESULTS: A 1,071 bp sequence was obtained. Sequence analysis showed that the fragment contained a complete open reading frame (ORF), encoding 278 amino acid residues. This target fragment was cloned into the prokaryotic expression vector pGEX-4T-1, and expressed in Escherichia coli. SDS-PAGE revealed that the molecular weight of the expressed fusion recombinant product was 56 kD. Western blot showed that the recombinant protein was recognized by polyclonal rabbit antiserum immunized with Schistosoma japonicum adult worm antigen. CONCLUSION: Cloning of the full-length gene encoding SjSDISP and its bacterial expression were successfully done.
