PLoS Neglected Tropical Diseases
·
2026
·Vol. 20
·期 3
·e0014052
·
IF 3.6
Jing Xie,Mengqi Wu,Zhijun Zhou,Yuan Liu,Xiaohua Liu,Kaijuan Wu,Dongqian Yang,Yixiao Wang,Kang Liu,Chandara Ngim,Zheng Wang,Liping Jiang
Toxoplasma gondii ( T. gondii ) is an intracellular parasite that infects nearly all warm-blooded animals, including humans. The susceptibility to T. gondii infection varies among hosts. In this study, we found that Microtus fortis ( M. fortis ) exhibited a naturally high level of resistance to the T. gondii RH strain, as evidenced by survival assays. We further observed that M. fortis activated the complement system via the lectin pathway to lyse T. gondii tachyzoites, whereas serum from Kunming (KM) mice showed no such effect. Furthermore, the ability of M. fortis to clear T. gondii tachyzoites was significantly impaired when the complement system was inhibited by cobra venom factor (CVF). These findings indicate that M. fortis exhibits a naturally high resistance to T. gondii . This resistance is mediated, in part, by the complement system, which is activated through the lectin pathway and directly lyses extracellular tachyzoites. Thus, the complement system plays an essential role in controlling T. gondii infection in this species.
T. gondii can infect nearly all warm-blooded animals. Mice infected with T. gondii type I strains typically develop acute toxoplasmosis symptoms and often succumb to the infection. However, we observed that M. fortis infected with the T. gondii type I strain did not develop acute toxoplasmosis and effectively cleared the T. gondii tachyzoites. Our study revealed that T. gondii tachyzoites activate the complement system in M. fortis via the lectin pathway, leading to their destruction by lysis. In contrast, the complement system in mice failed to eliminate the tachyzoites. Furthermore, complement inhibition in M. fortis significantly impaired its ability to clear the infection. These findings suggest that the complement system plays a critical role in enabling M. fortis to control T. gondii infection. The complement-mediated killing of T. gondii offers new insights for the development of anti- T. gondii drugs and vaccines.
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PLoS Pathogens
·
2026
·Vol. 22
·期 6
·e1013865
·
IF 4.9
Lin Zhao,Jiawen Fu,Swaroop Peddiraju,Heming Chen,Keqin Huang,Ying Zhang,Nishith Gupta,Qian Jiang,Honglin Jia
All alveolates including apicomplexan parasites contain an inner membrane complex (IMC) underneath the plasma membrane. The IMC is synthesized de novo during asexual replication (including endodyogeny, endopolygeny, and schizogony) and serves as a crucial scaffold for supporting cytoskeletal structures and the glideosome machinery for parasite locomotion. However, the mechanism(s) underlying the membrane biogenesis in the IMC are not well understood. Using a clinically-relevant and globally-prevalent pathogenic protist model, Toxoplasma gondii , we identified the TgVPS13A bridging the IMC to the endoplasmic reticulum (ER) – the major site of phospholipid synthesis. The multi-modular TgVPS13A plays a crucial role in the IMC biogenesis, functioning in concert with an ER-resident VAP protein (TgVAP) and a novel lipid scramblase (TgDAT1). TgDAT1 is recruited for the progeny formation sites during the early stages of budding. Conditional depletion of TgVPS13A, TgDAT1 or TgVAP results in collapse of the inner membrane complex, leading to parasite death, as visualized by endodyogeny-specific organelle markers. GFP-Lact-C2, a biosensor of phosphatidylserine and phosphatidylthreonine lipids made in the ER and enriched in the IMC, also mislocalizes upon protein depletion. In conclusion, we propose that TgVPS13A, together with TgVAP and TgDAT1, bridge the ER and IMC and mediate the inter-organelle transport of lipids, thus contributing to the organelle biogenesis and daughter budding in T. gondii.
The inner membrane complex (IMC) in apicomplexan parasites is essential for maintaining the structural stability of the parasite, as well as for its budding and motility. The IMC is composed of flattened vesicles, alveolins, and microtubules. However, the mechanism behind the biogenesis of these flattened vesicles remains unclear. In this study, we provide evidence that a bridge-like protein TgVPS13A, together with TgVAP and TgDAT1 drive the biogenesis of the IMC alveoli. Phenotypic analysis indicates that the absence of any individual of these proteins disrupts the biogenesis of daughter IMCs, which in turn affects the budding of daughter parasites. We also demonstrated that TgDAT1 functions as a scramblase. Based on our findings, we propose a model in which the TgVPS13A, functioning in concert with TgVAP and TgDAT1 mediates lipid transport from the ER to the nascent IMC to drive the expansion of the IMC membrane and the budding of daughter parasites in T. gondii . Furthermore, TgDAT1 may facilitate the transfer of lipids from the outer leaflet to the inner leaflet of the IMC sacs, promoting a balanced composition of the IMC membrane components.
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EUROPEAN JOURNAL OF PHARMACOLOGY
·
2021
·
IF 4.432
Jing-Mei Lu,Guang-Nan Jin,Yu-Nan Lu,Xu-Dong Zhao,Hui-Wen Lan,Shuai-Ru Mu,Xin-Yu Shen,Guang-Hua Xu,Cheng-Hua Jin,Juan Ma,Xuejun Jin,Xiang Xu,Lian-Xun Piao
Toxoplasma gondii ( T. gondii ) is an obligate intracellular parasite that can cause liver diseases in the host, including hepatitis and hepatomegaly . High mobility group box 1 (HMGB1) is the main inflammatory mediator causing cell injury or necrosis. HMGB1 binds to toll like receptor 4 (TLR4), then activates the nuclear factor-κB (NF-κB) signaling pathway, which promotes the release of inflammatory factors. Our previous studies showed that HMGB1 mediated TLR4/NF-κB signaling pathway plays an important role in liver injury induced by T. gondii infection. Resveratrol (RSV) is a small polyphenol, which has anti-inflammatory, anti-cancer, anti- T. gondii effect. However, the effect of RSV on liver injury caused by T. gondii infection is unclear. This study used the RH strain tachyzoites of T. gondii to infect murine liver line, NCTC-1469 cells to establish an in vitro model and acute infection of mice for the in vivo model to explore the protective effect of RSV on liver injury induced by T. gondii infection. The results showed that RSV inhibited the proliferation of T. gondii in the liver, reduced the alanine aminotransferase/aspartate aminotransferase levels and pathological liver damage. Additionally, RSV inhibited the production of tumor necrosis factor-α, inducible nitric oxide synthase and HMGB1 by interfering with the TLR4/NF-κB signaling pathway. These results indicate that RSV can protect liver injury caused by T. gondii infection by intervening in the HMGB1/TLR4/NF-κB signaling pathway. This study will provide a theoretical basis for RSV treatment of T. gondii infection induced liver injury.
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Vaccines
·
2020
·Vol. 8
·期 4
·731
·
IF 4.086
Zhengqing Yu,Tianyuan Zhou,Yanxin Luo,Lu Dong,Chunjing Li,Junlong Liu,Jianxun Luo,Ruofeng Yan,Lixin Xu,Xiaokai Song,Xiangrui Li
Toxoplasma gondii(T. gondii) is the most common zoonotic protozoa and has infected about one-third of the population worldwide. Recombinant epitopes encapsulated in nanospheres have advantages over traditionalT. gondiivaccines. For an efficient delivery system, poly (DL-lactide-co-glycolide) (PLGA) and chitosan are the most frequently used biodegradable polymeric nanospheres with strong safety profiles. In the present study, we first expressed and purified histone H2A1 ofT. gondiiusing the prokaryotic expression system. The effects of recombinant TgH2A1 on the functions of murine macrophages were then studied. Purified recombinant TgH2A1 was then encapsulated in nanospheres with PLGA and chitosan. After subcutaneous vaccination in mice, the immune response was evaluated by double antibody sandwich ELISA kits. The results from this study showed that PLGA and chitosan loaded with rTgH2A1 could trigger a stronger Th1 oriented immune response and prolong the survival time of mice effectively. In conclusion, PLGA and chitosan nanospheres loaded with histone H2A1 are an effective method for the development of vaccines againstT. gondii. Further studies should focus on evaluating the regulatory mechanism of TgH2A1, vaccine potency, and cellular response in chronicT. gondiiinfections.Keywords:Toxoplasma gondii;H2A1;murine macrophage;nanoparticles;PLGA;chitosan;immune response
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Frontiers in Immunology
·
2021
·
IF 7.561
Yu Zhengqing,Cao Wandi,Gao Xuchen,Aleem Muhammad Tahir,Liu Junlong,Luo Jianxun,Yan Ruofeng,Xu Lixin,Song Xiaokai,Li Xiangrui
Toxoplasma gondii (T. gondii) is an intracellular parasitic protozoan that can cause serious public health problems. However, there is no effectively preventive or therapeutic strategy available for human and animals. In the present study, we developed a DNA vaccine encoding T. gondii oxidoreductase from short-chain dehydrogenase/reductase family (TgSDRO-pVAX1) and then entrapped in chitosan and poly lactic-co-glycolic acid (PLGA) to improve the efficacy. When encapsulated in chitosan (TgSDRO-pVAX1/CS nanospheres) and PLGA (TgSDRO-pVAX1/PLGA nanospheres), adequate plasmids were loaded and released stably. Before animal immunizations, the DNA vaccine was transfected into HEK 293-T cells and examined by western blotting and laser confocal microscopy. Th1/Th2 cellular and humoral immunity was induced in immunized mice, accompanied by modulated secretion of antibodies and cytokines, promoted the maturation and MHC expression of dendritic cells, and enhanced the percentages of CD4+ and CD8+ T lymphocytes. Immunization with TgSDRO-pVAX1/CS and TgSDRO-pVAX1/PLGA nanospheres conferred significant immunity with lower parasite burden in the mice model of acute toxoplasmosis. Furthermore, our results also lent credit to the idea that TgSDRO-pVAX1/CS and TgSDRO-pVAX1/PLGA nanospheres are substitutes for each other. In general, the current study proposed that TgSDRO-pVAX1 with chitosan or PLGA as the delivery vehicle is a promising vaccine candidate against acute toxoplasmosis.
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INTERNATIONAL IMMUNOPHARMACOLOGY
·
2023
·
IF 5.6
Xin-Yu Shen,Jing-Mei Lu,Yu-Nan Lu,Guang-Nan Jin,Jing-Wen Ma,Jing-He Wang,Yu Wang,Xiang Xu,Lian-Xun Piao
Toxoplasma gondii ( T. gondii ) is an obligate intracellular protozoan parasite that causes pulmonary toxoplasmosis, although its pathogenesis is incompletely understood. There is no cure for toxoplasmosis. Coixol, a plant polyphenol extracted from coix seeds, has a variety of biological activities. However, the effects of coixol on T. gondii infection have not been clarified. In this study, we infected a mouse macrophage cell line (RAW 264.7) and BALB/c mice with the T. gondii RH strain to establish infection models in vitro and in vivo , respectively, to explore protective effects and potential mechanisms of coixol on lung injury caused by T. gondii infection. Anti- T. gondii effects and underlying anti-inflammatory mechanisms of coixol were investigated by real-time quantitative PCR, molecular docking, localized surface plasmon resonance, co-immunoprecipitation, enzyme-linked immunosorbent assay, western blotting, and immunofluorescence microscopy. The results show that coixol inhibits T. gondii loads and T. gondii -derived heat shock protein 70 ( T.g. HSP70) expression. Moreover, coixol reduced inflammatory cell recruitment and infiltration, and ameliorated pathological lung injury induced by T. gondii infection. Coixol can directly bind T.g. HSP70 or Toll-like receptor 4 (TLR4) to disrupt their interaction. Coixol prevented overexpression of inducible nitric oxide synthase, tumor necrosis factor-α, and high mobility group box 1 by inhibiting activation of the TLR4/nuclear factor (NF)-κB signaling pathway, consistent with effects of the TLR4 inhibitor CLI-095. These results indicate that coixol improves T. gondii infection-induced lung injury by interfering with T.g. HSP70-mediated TLR4/NF-κB signaling. Altogether, these findings suggest that coixol is a promising effective lead compound for the treatment of toxoplasmosis.
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Microbial Biotechnology
·
2024
·Vol. 17
·期 4
·e14455
·
IF 4.8
Xuke Yang,Jichao Yang,Mengyu Lyu,Yaqiong Li,Anqi Liu,Bang Shen
Toxoplasma gondii is a zoonotic parasite infecting humans and nearly all warm-blooded animals. Successful parasitism in diverse hosts at various developmental stages requires the parasites to fine tune their metabolism according to environmental cues and the parasite's needs. By manipulating the β and γ subunits, we have previously shown that AMP-activated protein kinase (AMPK) has critical roles in regulating the metabolic and developmental programmes. However, the biological functions of the α catalytic subunit have not been established. T. gondii encodes a canonical AMPKα, as well as a KIN kinase whose kinase domain has high sequence similarities to those of classic AMPKα proteins. Here, we found that Tg KIN is dispensable for tachyzoite growth, whereas Tg AMPKα is essential. Depletion of Tg AMPKα expression resulted in decreased ATP levels and reduced metabolic flux in glycolysis and the tricarboxylic acid cycle, confirming that Tg AMPK is involved in metabolic regulation and energy homeostasis in the parasite. Sequential truncations at the C-terminus found an α-helix that is key for the function of Tg AMPKα. The amino acid sequences of this α-helix are not conserved among various AMPKα proteins, likely because it is involved in interactions with Tg AMPKβ, which only have limited sequence similarities to AMPKβ in other eukaryotes. The essential role of the less conserved C-terminus of Tg AMPKα provides opportunities for parasite specific drug designs targeting Tg AMPKα.
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PLoS Pathogens
·
2023
·Vol. 19
·期 3
·e1011288
·
IF 6.7
Jiawen Fu,Lin Zhao,Juan Yang,Heming Chen,Shinuo Cao,Honglin Jia
Exocytosis is a key active process in cells by which proteins are released in bulk via the fusion of exocytic vesicles with the plasma membrane. Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein-mediated vesicle fusion with the plasma membrane is essential in most exocytotic pathways. In mammalian cells, the vesicular fusion step of exocytosis is normally mediated by Syntaxin-1 (Stx1) and SNAP25 family proteins (SNAP25 and SNAP23). However, in Toxoplasma gondii , a model organism of Apicomplexa, the only SNAP25 family protein, with a SNAP29-like molecular structure, is involved in vesicular fusion at the apicoplast. Here, we reveal that an unconventional SNARE complex comprising TgStx1, TgStx20, and TgStx21 mediates vesicular fusion at the plasma membrane. This complex is essential for the exocytosis of surface proteins and vesicular fusion at the apical annuli in T . gondii .
Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins that mediate exocytosis in T . gondii have not been well identified. In this study, the functions of two unique SNAREs, TgStx20 and TgStx21, that share homology with the C- and N-terminal SNARE domains of SNAP23 were investigated through tagging an auxin-inducible degron system. The results indicate that both SNAREs are required for the lytic cycle of this parasite. Depletion of TgStx20 or TgStx21 caused a deficiency of exocytosis of surface proteins. In particular, the SNARE proteins located in T . gondii apical annuli were demonstrated to be required for the fusion of Rab11A-positive vesicles at these sites for the first time. We also found that a conserved Qa SNARE, TgStx1, forms a complex with TgStx20 and TgStx21. Depletion of TgStx1 in parasites caused similar phenotypes as those observed in TgStx20- or TgStx21-deficient parasites. These data reveal a unique SNARE complex that mediates vesicular fusion at the plasma membrane and provide further insight into the molecular mechanism of the vesicular trafficking pathway to the apical annuli.
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Parasites & Vectors
·
2024
·Vol. 17
·期 1
·1-13
·
IF 3
Fan Jiyuan,Sun Hao,Fang Jiawen,Gao Yafan,Ding Haojie,Zheng Bin,Kong Qingming,Zhuo Xunhui,Lu Shaohong
Background Timely diagnosis of Toxoplasma gondii infection is necessary to prevent and control toxoplasmosis transmission. The gold immunochromatographic assay (GICA) is a means of rapidly detecting pathogen in samples. GICA-based diagnostic methods have been developed to accurately detect pathogens with high sensitivity and specificity, and their application in T. gondii diagnosis is expected to yield good results.Methods Colloidal gold test strips were produced using T. gondii C-terminal truncated apical membrane antigen 1 (AMA1C). Colloidal gold-AMA1C and colloidal gold-murine protein conjugate were synthesized under optimal conditions. A nitrocellulose membrane was treated with AMA1C and goat anti-mouse antibody as the test line and control line, respectively. In total, 90 cat serum samples were tested using AMA1C-GICA and a commercial enzyme linked immunosorbent assay (ELISA) kit. The GICA results were digitally displayed using a portable colloidal gold immunochromatographic test strip analyzer (HMREADER). The sensitivity, specificity, and stability of AMA1C-GICA were assessed, and this was then used to examine clinical samples, including 203 human sera, 266 cat sera, and 81 dog sera.Results AMA1C-GICA had a detection threshold of 1:32 for T. gondii-positive serum. The GICA strips specifically detected T. gondii antibodies and exhibited no reactivity with Plasmodium vivax, Paragonimus kellicotti, Schistosoma japonicum, Clonorchis sinensis, and Schistosoma mansoni. Consequently, 15 (16.7%) positive samples were detected using the AMA1C-GICA and commercial ELISA kits for each of the assays. The receiver-operating characteristic curve showed that GICA had a relative sensitivity of 85.3% and specificity of 92%, with an area under the curve of 98%. After analyzing clinical samples using HMREADER, 1.2%–23.4% of these samples were found to be positive for T. gondii.Conclusion sThis study presents a novel assay that enables timely and efficient detection of serum antibodies against T. gondii, thereby allowing for its early clinical diagnosis. Furthermore, the integration of digital detection using HMREADER can enhance the implementation of GICA.Graphical Abstract
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Autophagy
·
2026
·
IF 18.6
Hao Xu,Hailong Liu,Taozhen Lu,Yuken Chen,Yazhou Li,Yuchao Zhu,Liting Wei,Bolin Fan,Yonghui Zhang,Chuangshi Zhang,Rui Fang,Shengsong Xie,Bang Shen
Toxoplasma gondii is a globally prevalent foodborne zoonotic pathogen that threatens animal production and human health. Consumption of undercooked meat like pork and lamb is a major route of human infection. In this study, we performed a genome-wide CRISPR knockout screen in the porcine cell line PK15 to identify host factors that are critical for T. gondii replication. The results showed that disrupting the ELFN2 (extracellular leucine rich repeat and fibronectin type III domain containing 2) gene in PK15 did not affect host cell growth, but significantly reduced the proliferation of Toxoplasma parasites. Loss of ELFN2 decreased macroautophagy/autophagy in PK15 cells and impaired lipid metabolism, resulting in reduced lipid availability for the parasites and consequent suppression of T. gondii proliferation. Exogenous lipid supplementation or pharmacological activation of autophagy could fully restore the replication of parasites in ΔELFN2 cells. The requirement of host ELFN2 for optimal parasite proliferation in vivo was validated by constructing elfn2−/− mice, which showed increased resistance to T. gondii infection and reduced parasite burden, highlighting the value of ELFN2 in breeding Toxoplasma-resistant animals. Notably, naturally occurring loss-of-function mutations in ELFN2 could be found in certain pig breeds, further indicating the feasibility of breeding T. gondii-resistant animals like pigs, to reduce the transmission of Toxoplasma.
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BMC Veterinary Research
·
2023
·Vol. 19
·期 1
·1-11
·
IF 2.6
Gao Yafan,Shen Yu,Fan Jiyuan,Ding Haojie,Zheng Bin,Yu Haijie,Huang Siyang,Kong Qingming,Lv Hangjun,Zhuo Xunhui,Lu Shaohong
Background Diseases caused by Toxoplasma gondii ( T. gondii ) have introduced serious threats to public health . There is an urgent need to develop a rapid detection method for T. gondii infection in cats, which are definitive hosts. Recombinant apical membrane antigen 1 (rAMA1) was produced in a prokaryotic expression system and used as the detection antigen. The aim of this study was to evaluate and optimize a reliable indirect enzyme-linked immunosorbent assay (iELISA) method based on rAMA1 for the detection of antibodies against T. gondii in cats. Results The rAMA1-iELISA method was developed and optimized by the chessboard titration method. There were no cross-reactions between T. gondii -positive cat serum and positive serum for other pathogens, indicating that rAMA1-iELISA could only detect T. gondii in most cases. The lowest detection limit of rAMA1-iELISA was 1:3200 (dilution of positive serum), and the CV of repeated tests within batches and between batches were confirmed to be less than 10%. The results of 247 cat serum samples detected by rAMA1-iELISA (kappa value = 0.622, p < 0.001) were in substantial agreement with commercial ELISA. The ROC curve analysis revealed the higher overall check accuracy of rAMA1-iELISA (sensitivity = 91.7%, specificity = 93.6%, AUC = 0.956, 95% CI 0.905 to 1.000) than GRA7-based iELISA (sensitivity = 91.7%, specificity = 85.5%, AUC = 0.936, 95% CI 0.892 to 0.980). Moreover, the positive rate of rAMA1-iELISA (6.5%, 16/247) was higher than that of GRA7-based iELISA (3.6%, 9/247) and that of commercial ELISA kit (4.9%, 12/247). Conclusion The iELISA method with good specificity, sensitivity, and reproducibility was established and can be used for large-scale detection of T. gondii infection in clinical cat samples.
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Frontiers in Immunology
·
2024
·
IF 5.7
Qi WeiYu,Yu YouLi,Yang ChenChen,Wang XiaoJuan,Jiang YuChen,Zhang Li,Yu ZhengQing
Toxoplasma gondii (T. gondii) is a zoonotic disease that poses great harm to humans and animals. So far, no effective T. gondii vaccine has been developed to provide fully protection against such parasites. Recently, numerous researches have focused on the use of poly-lactic-co-glycolic acid (PLGA) and chitosan (CS) for the vaccines against T. gondii infections. In this study, we employed PLGA and CS as the vehicles for T. gondii ribosome protein (TgRPS2) delivery. TgRPS2-PLGA and TgRPS2-CS nanospheres were synthesized by double emulsion solvent evaporation and ionic gelation technique as the nano vaccines. Before immunization in animals, the release efficacy and toxicity of the synthesized nanospheres were evaluated in vitro. Then, ICR mice were immunized intramuscularly, and immune protections of the synthesized nanospheres were assessed. The results showed that TgRPS2-PLGA and TgRPS2-CS nanospheres could induce higher levels of IgG and cytokines, activate dendritic cells, and promote the expression of histocompatibility complexes. The splenic lymphocyte proliferation and the enhancement in the proportion of CD4+ and CD8+ T lymphocytes were also observed in immunized animals. In addition, two types of nanospheres could significantly inhabit the replications of T. gondii in cardiac muscles and spleen tissues. All these obtained results in this study demonstrated that the TgRPS2 protein delivered by PLGA or CS nanospheres provided satisfactory immunoprotective effects in resisting T. gondii, and such formulations illustrated potential as prospective preventive agents for toxoplasmosis.
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