Sja-let-7 suppresses the development of liver fibrosis via Schistosoma japonicum extracellular vesicles.

Schistosomiasis is a fatal zoonotic parasitic disease that also threatens human health. The main pathological features of schistosomiasis are granulomatous inflammation and subsequent liver fibrosis, which is a complex, chronic, and progressive disease. Extracellular vesicles (EVs) derived from schistosome eggs are broadly involved in host-parasite communication and act as important contributors to schistosome-induced liver fibrosis. However, it remains unclear whether substances secreted by the EVs of Schistosoma japonicum, a long-term parasitic "partner" in the hepatic portal vein of the host, also participate in liver fibrosis. Here, we report that EVs derived from S. japonicum worms attenuated liver fibrosis by delivering sja-let-7 into hepatic stellate cells (HSCs). Mechanistically, activation of HSCs was reduced by targeting collagen type I alpha 2 chain (Col1α2) and downregulation of the TGF-ß/Smad signaling pathway both in vivo and in vitro. Overall, these results contribute to further understanding of the molecular mechanisms underlying host-parasite interactions and identified the sja-let-7/Col1α2/TGF-ß/Smad axis as a potential target for treatment of schistosomiasis-related liver fibrosis.

Characteristics of Th9 cells in Schistosoma japonicum-infected C57BL/6 mouse mesenteric lymph node.

Interleukin 9 (IL-9) is an effective cytokine secreted by newly defined Th9 cells, which is involved in allergic and infectious diseases. In this study, lymphocytes were isolated from mesenteric lymph node (MLN), spleen, liver, lung, and Peyer's patches (PP) of C57BL/6 mice 5-6 weeks after S. japonicum infection, intracellular cytokine staining was done to detect the percentage of IL-9-producing CD4+ T cells. The qPCR and ELISA were used to verify the content of IL-9 in MLN. The population of IL-9-producing lymphocyte subset was identified by FACS. In addition, the dynamic changes and cytokine profiles of Th9 cells in the MLN of infected mice were detected by FACS. ELISA was used to detect IL-9 induced by soluble egg antigen (SEA) from isolated lymphocytes in mouse MLN. The results showed that the percentage of IL-9-secreting Th9 cells in the MLN of the infected mouse was higher than that in the spleen, liver, lung, or PP. Though CD8+ Tc cells, NKT cells, and γδT cells could secrete IL-9, CD4+ Th cells were the main source of IL-9 in S. japonicum-infected C57BL/6 mice (P < 0.05). The percentage of Th9 cells in MLN of infected mouse increased from week 3-4, and reached a peak at week 5-6, then began to decrease from week 7-8 (P < 0.05). Moreover, Th9 cells could also secrete a small amount of IL-4, IFN-γ, IL-5, and IL-10. Our results suggested a higher percentage of Th9 cells was induced in the MLN of S. japonicum-infected mice, which might play an important role in the early stage of S. japonicum-induced disease.

Longitudinal Immune Profiling Highlights CD4+ T Cell Exhaustion Correlated with Liver Fibrosis in Schistosoma japonicum Infection.

Schistosomiasis remains an important public health concern. The eggs deposited in livers invoke a Th2-dominant response, which mediates the fibrotic granulomatous response. However, the mechanisms involved in this immunopathological process are still not perfectly clear. Here, we report a single-cell transcriptional landscape of longitudinally collected BALB/c mouse splenocytes at different time points after Schistosoma japonicum infection. We found that exhausted CD4+ T cells were enriched after infection, changing from coproducing multiple cytokines to predominantly producing the Th2 cytokine IL-4. Regulatory B cells had high expression of Fcrl5, Ptpn22, and Lgals1, potentially regulating exhausted CD4+ T cells via direct PD-1-PD-L2 and PD-1-PD-L1 interactions. Within the myeloid compartment, the number of precursor and immature neutrophils sharply increased after infection. Moreover, dendritic cells, macrophages, and basophils showed inhibitory interactions with exhausted CD4+ T cells. Besides, in mouse livers, we found that exhausted CD4+ T cells were distributed around egg granuloma, promoting collagen expression in primary mouse hepatic stellate cells via IL-4 secretion, resulting in liver fibrosis. Our study provides comprehensive characterization of the composition and cellular states of immune cells with disease progression, which will facilitate better understanding of the mechanism underlying liver fibrotic granulomatous response in schistosomiasis.

Pathology and molecular mechanisms of Schistosoma japonicum-associated liver fibrosis.

Schistosomiasis has been widely disseminated around the world, and poses a significant threat to human health. Schistosoma eggs and soluble egg antigen (SEA) mediated inflammatory responses promote the formation of egg granulomas and liver fibrosis. With continuous liver injuries and inflammatory stimulation, liver fibrosis can develop into liver cirrhosis and liver cancer. Therefore, anti-fibrotic therapy is crucial to increase the survival rate of patients. However, current research on antifibrotic treatments for schistosomiasis requires further exploration. In the complicated microenvironment of schistosome infections, it is important to understand the mechanism and pathology of schistosomiasis-associated liver fibrosis(SSLF). In this review, we discuss the role of SEA in inhibiting liver fibrosis, describe its mechanism, and comprehensively explore the role of host-derived and schistosome-derived microRNAs (miRNAs) in SSLF. Inflammasomes and cytokines are significant factors in promoting SSLF, and we discuss the mechanisms of some critical inflammatory signals and pro-fibrotic cytokines. Natural killer(NK) cells and Natural killer T(NKT) cells can inhibit SSLF but are rarely described, therefore, we highlight their significance. This summarizes and provides insights into the mechanisms of key molecules involved in SSLF development.

[Imbalance of Th17/Tregs promotes egg granuloma formation of liver with Schistosomiasis japonicum in mice].

Objectives To investigate the effect of the imbalance of Th17/Treg on egg granuloma formation of liver with Schistosomiasis japonicum. Methods The BALB/c mice were infected with Schistosoma japonicum cercariae to establish a model of Schistosomiasis japonica. The blood samples, liver tissues and spleen tissue were harvested at the 2nd, 4th, 6th, 8th week, respectively. HE staining and Masson staining were performed to assess the pathological characteristics of the liver. Flow cytometry (FCM) was conducted to evaluate the proportion of CD4+ T cell subsets including Th17 cells and Tregs in liver and spleen tissue. The quantitative real-time PCR (qRT-PCR) was carried out to investigate the mRNA level of cytokines including RORγt, FOXP3, IL-6, IL-17, IL-23 and IL-10 in liver tissues. Finally, ELISA was performed to assess the serum level of cytokines including IL-6, IL-17, IL-23 and TGF-ß. Schistosoma japonicium soluble egg antigen (SjSEA) were prepared to stimulate mouse spleen cells in vitro. qRT-PCR was carried out to investigate the mRNA level of cytokine including RORγt and FOXP3 and ELISA was performed to assess the expression level of cytokines including IL-6, IL-17, IL-23 and TGF-ß at different time points. Results HE and Masson staining demonstrated that inflammatory cell infiltration, schistosome egg granuloma formation and the collagen deposition increased in the liver tissue after the 4th week. The longer the infection, the more severe the liver pathology. In the liver and spleen tissues, the percentage of Th17 cells of infection group (2nd, 4th and 6th weeks) were significantly higher than the healthy group. The percentage of Tregs in the liver tissues of infection group (4th, 6th and 8th weeks) were significantly higher than the healthy group, and the percentage of Tregs in the spleen of infection group (2nd and 4th weeks) were significantly higher than the healthy group. Th17/Treg ratios in the liver of infection group were lower than the healthy group. Th17/Treg ratios in the spleen of infection group (2nd and 4th weeks) were lower than the healthy group, while it increased in the 6th week. At the same time, the levels of Th17 cells and Tregs related nuclear transcription factors and cytokines showed similar dynamic changes as the percentages of T cell subsets. SjSEA can induce the differentiation of Th17 and Tregs and the expression of related cytokines and transcription factors. Conclusion Th17 cells may play a major role in liver pathology, and the imbalance of Th17 cells/Tregs was closely related to the schistosome egg granuloma formation.

IL-37 alleviates liver granuloma caused by Schistosoma japonicum infection by inducing alternative macrophage activation.

BACKGROUND: Hepatic macrophages regulate liver granuloma formation and fibrosis caused by infection with Schistosoma japonicum, with the manner of regulation dependent on macrophage activation state. Interleukin (IL)-37 may have immunomodulatory effects on macrophages. However, whether IL-37 can affect liver granuloma formation and fibrosis by affecting the polarization of macrophages in S. japonicum infection remains unclear. The aim of this study was to investigate IL-37-affected macrophage polarization in liver granuloma formation and fibrosis in S. japonicum infection. METHODS: An enzyme-linked immunosorbent assay (ELISA) was used to detect the expression of IL-37 in the serum of patients with acute S. japonicum infection and in the serum of healthy people. Recombinant IL-37 (rIL-37), CPP-IgG2Fc-IL-37 and no CPP-IgG2Fc-IL-37 proteins were injected into S. japonicum-infected mice every 3 days for a total of 6 times from day 24 post infection onwards. Subsequently, ELISA, quantitative reverse transcription-PCR, fluorescence-activated cell sorting and western blot were used to analyze whether IL-37 inhibits the formation of liver granulomas and the development of liver fibrosis by regulating the phenotypic transition of macrophages. Finally, the three IL-37 proteins and SIS3, a Smad3 inhibitor, were co-cultured in mouse peritoneal macrophages to explore the mechanism underlying the promotion of the polarization of M0 macrophages to the M2 phenotype by IL-37. RESULTS: Serum IL-37 levels were upregulated in schistosomiasis patients, and this increased level of IL-37 protein apparently alleviated the liver granuloma of mice in infection models. It also could induce liver and peritoneal macrophages to polarize to the M2 phenotype in S. japonicum-infected mice. The S. japonicum-infected mice injected with CPP-IgG2Fc-IL-37 group exhibited the most obvious improvement in inflammatory reaction against the liver granuloma. The number and ratio of M2 macrophages in the liver and peritoneal cavity were significantly higher in the three IL-37 protein groups, especially in the CPP-IgG2Fc-IL-37 group, compared to the controls. Similar results were also found regarding liver function damage. IL-37 induced macrophage M2 polarization by promoting AMP-activated protein kinase (AMPK) phosphorylation in vitro. Among all groups, the activation of AMPK was most significant in the CPP-IgG2Fc-IL-37 group, and it was found that SMAD3 could enhance the anti-inflammatory function of IL-37. CONCLUSIONS: The results show that IL-37 was able to promote the polarization of macrophages to the M2 phenotype, thereby inhibiting the development of schistosomiasis. In comparison to the rIL-37 protein, the CPP-IgG2Fc-IL-37 protein has the advantages of being effective in small doses and having fewer side effects and a better efficacy.

Genome-Wide Association Study Identifies New Risk Loci for Progression of Schistosomiasis Among the Chinese Population.

Schistosoma japonicum infections, which lead to local inflammatory responses to schistosome eggs trapped in host tissues, can result in long-term, severe complications. The development of schistosomiasis may result from a complex interaction between the pathogenic, environmental, and host genetic components. Notably, the genetic factors that influence the development of schistosomiasis complications are poorly understood. Here we performed a genome-wide association study on multiple schistosomiasis-related phenotypes of 637 unrelated schistosomiasis patients in the Chinese population. Among three indicators of liver damage, we identified two novel, genome-wide significant single-nucleotide polymorphisms (SNPs) rs34486793 (P = 1.415 × 10-8) and rs2008259 (P = 6.78 × 10-8) at locus 14q32.2 as well as a gene, PMEPA1, at 20q13.31 (index rs62205791, P = 6.52 × 10-7). These were significantly associated with serum levels of hyaluronic acid (HA). In addition, RASIP1 and MAMSTR at 19q13.33 (index rs62132778, P = 1.72 × 10-7) were significantly associated with serum levels of aspartate aminotransferase (AST), and TPM1 at 15q22.2 (index rs12442303, P = 4.39 × 10-7) was significantly associated with serum levels of albumin. In schistosomiasis clinical signs, ITIH4 at 3p21.1 (index rs2239548) was associated with portal vein diameter (PVD) class, an indicator of portal hypertension, and OGDHL at 10q11.23 (index rs1258172) was related to ascites grade. We also detected an increased expression of these six genes in livers of mice with severe schistosomiasis. Summary data-based Mendelian randomization analyses indicated that ITIH4, PMEPA1 and MAMSTR were pleiotropically associated with PVD class, HA and AST, respectively.

Hepatic progenitor cells promote the repair of schistosomiasis liver injury by inhibiting IL-33 secretion in mice.

BACKGROUND: Hepatic schistosomiasis, a chronic liver injury induced by long-term Schistosoma japonicum (S. japonicum) infection, is characterized by egg granulomas and fibrotic pathology. Hepatic progenitor cells (HPCs), which are nearly absent or quiescent in normal liver, play vital roles in chronic and severe liver injury. But their role in the progression of liver injury during infection remains unknown. METHODS: In this study, the hepatic egg granulomas, fibrosis and proliferation of HPCs were analyzed in the mice model of S. japonicum infection at different infectious stages. For validating the role of HPCs in hepatic injury, tumor necrosis factor-like-weak inducer of apoptosis (TWEAK) and TWEAK blocking antibody were used to manipulate the proliferation of HPCs in wild-type and IL-33-/- mice infected with S. japonicum. RESULTS: We found that the proliferation of HPCs was accompanied by inflammatory granulomas and fibrosis formation. HPCs expansion promoted liver regeneration and inhibited inflammatory egg granulomas, as well as the deposition of fibrotic collagen. Interestingly, the expression of IL-33 was negatively associated with HPCs' expansion. There were no obvious differences of liver injury caused by infection between wild-type and IL-33-/- mice with HPCs' expansion. However, liver injury was more attenuated in IL-33-/- mice than wild-type mice when the proliferation of HPCs was inhibited by anti-TWEAK. CONCLUSIONS: Our data uncovered a protective role of HPCs in hepatic schistosomiasis in an IL-33-dependent manner, which might provide a promising progenitor cell therapy for hepatic schistosomiasis.

STAT3 Promotes Schistosome-Induced Liver Injury by Inflammation, Oxidative Stress, Proliferation, and Apoptosis Signal Pathway.

Schistosomiasis is a parasitic helminth disease that can cause organ lesions leading to health damage. During a schistosome infection, schistosome eggs can flow into the liver along the portal vein. Numerous inflammatory cells gather around the eggs, causing granulomas and fibrosis in the liver. In this process, many molecules are involved in the initiation and regulation of the fibrous scar formation. However, the precise molecular mechanisms responsible for the progression of granuloma formation and fibrosis initiation caused by schistosome infection have not been extensively studied. In this study, C57BL/6 wild-type mice and Stat3flox/flox Alb-Cre mice were infected with cercariae of Schistosoma japonicum Liver injury, effector molecule levels, and RNA transcriptome resequencing of liver tissue were detected at 4, 5, and 6 weeks postinfection. We investigated the role of STAT3 (signal transducer and activator of transcription 3) in Schistosoma-induced liver injury in mice. After 6 weeks postinfection, there was obvious liver fibrosis. A sustained pathological process (inflammation, oxidative stress, proliferation, and apoptosis) occurred in S. japonicum-induced liver fibrosis initiation. Meanwhile, we observed activation of the STAT3 pathway in hepatic injury during S. japonicum infection by RNA transcriptome resequencing. Liver deficiency of phospho-STAT3 alleviated infection-induced liver dysfunction, hepatic granuloma formation, and fibrosis initiation. It also promoted STAT3-dependent apoptosis and reduced liver inflammation, oxidative stress, and proliferation. Our results suggest that STAT3 signal pathway and its mediating inflammation, oxidative stress, proliferation, and apoptosis are involved in S. japonicum-induced liver injury and may be a new potential guideline for the treatment of schistosomiasis.

Functional Inhibition of Natural Killer Cells in a BALB/c Mouse Model of Liver Fibrosis Induced by Schistosoma japonicum Infection.

Background and Aims: Schistosomiasis japonica is a widespread human zoonotic disease, and in China, there are many patients with schistosomiasis suffering from liver fibrosis. Many studies have shown that natural killer (NK) cells could reduce the progression of hepatic fibrosis by directly killing hepatic stellate cells (HSCs). However, NK cells could not inhibit the progress of liver fibrosis induced by Schistosoma japonicum infection. We aimed to investigate the function of NK cells in schistosomiasis. Methods: BALB/c mice were infected with S. japonicum cercariae. The receptors and their proportions expressed on NK cells in the liver and spleen from infected mice were detected using flow cytometry. Levels of IFN-γ, perforin, and granzyme of NK cells, and collagen I, III, and α-SMA of hepatic tissue, were detected using quantitative real-time PCR. Changes in cytokine levels in sera were detected using a cytometric bead array. Liver fibrosis was evaluated using hematoxylin and eosin and Masson staining. NK function in the schistosomiasis model was analyzed. Results: From 2 to 4 weeks post-infection, NK cells were activated, with significantly increased levels of effector molecules (IFN-γ, perforin, and granzyme) that peaked at 4 weeks after infection. The proportion of NK cells increased in the liver and spleen from 6 to 10 weeks post-infection. However, the function of NK cells was inhibited from 6 to 10 weeks post-infection with significantly decreased levels of activated receptors (AR), inhibitory receptors (IR), and effector molecules. The levels of IFN-γ, IL-12, and IL-6 in mouse serum peaked at 6 weeks post-infection, and IL-10 and IL-21 levels peaked at 8 weeks post-infection. Hepatic fibrosis markers increased significantly at 6 weeks after infection. Conclusion: Our study suggested that NK cells were activated from 2 to 4 weeks post-infection and participated in inflammation in the mouse model. After the S. japonicum laid their eggs, NK cells became inhibited, with decreased levels of both activating and inhibitory NK cell receptors, as well as cytotoxic molecules. In addition, liver fibrosis formed. In mice infected with S. japonicum, the process of liver fibrosis might be alleviated by removing the functional inhibition of NK cells.

ApoE deficiency promotes hepatic pathology by aggravating Th17/Treg imbalance in murine schistosomiasis japonica.

AIMS: The Schistosoma japonicum (S japonicum)-infected ApoE gene deficiency (ApoE-/- ) mice were used to determine effect of ApoE on hepatic immunopathology. METHODS: Murine activities and appetite, body weight, and ratio of liver weight to its body weight (Hepatic mass index, HMI) were observed. Worm load and liver egg burden were evaluated as the infection intensity. Number and size of liver egg granulomas and serum levels of alanine aminotransferase (ALT) were investigated. We analysed hepatic fibrosis by markers of fibrosis in tissue, detected hepatic Th17 and Treg frequency by flow cytometry, and measured hepatic expressions of RORγt, Foxp3, IL-17A and TGF-ß1 via qPCR. Lipid metabolism was determined by serum levels of cholesterol (TC) and triglyceride (TG) as well as hepatic Oil red O staining. RESULTS: In the infected ApoE-/- mice, the increased infection intensity aggravated the hepatic immunopathology (evidenced by increased HMI, elevated egg granulomas and increased ALT levels) and fibrosis (increased hepatic collagen deposition). ApoE deficiency resulted in significantly elevated ratio of hepatic Th17/Treg and higher serum levels of TC and TG, along with higher level of hepatic Oil red O staining. CONCLUSIONS: ApoE deficiency promotes hepatic pathology and fibrosis by exacerbating Th17/Treg imbalance and altering lipid metabolism in murine schistosomiasis japonica.

IL-17A-producing γδ T cells promote liver pathology in acute murine schistosomiasis.

BACKGROUND: The main symptoms of schistosomiasis are granuloma and fibrosis, caused by Schistosoma eggs. Numerous types of cells and cytokines are involved in the progression of Schistosoma infection. As a class of innate immune cells, γδ T cells play critical roles in the early immune response. However, their role in modulating granuloma and fibrosis remains to be clarified. METHODS: Liver fibrosis in wild-type (WT) mice and T cell receptor (TCR) δ knockout (KO) mice infected with Schistosoma japonicum was examined via Masson's trichrome staining of collagen deposition and quantitative reverse transcriptase-PCR (RT-PCR) of fibrosis-related genes. Granuloma was detected by hematoxylin-eosin (H&E) staining and quantified. Flow cytometry was used for immune cell profiling and for detecting cytokine secretion. The abundance of the related cytokines was measured using quantitative RT-PCR. RESULTS: The livers of S. japonicum-infected mice had significantly increased proportions of interleukin (IL)-17A producing γδ T cells and secreted IL-17A. Compared with the WT mice, TCR δ deficiency resulted in reduced pathological impairment and fibrosis in the liver and increased survival in infected mice. In addition, the profibrogenic effects of γδ T cells in infected mice were associated with enhanced CD11b+Gr-1+ cells, concurrent with increased expression of transforming growth factor (TGF)-ß in the liver. CONCLUSIONS: In this mouse model of Schistosoma infection, γδ T cells may promote liver fibrosis by recruiting CD11b+Gr-1+ cells. These findings shed new light on the pathogenesis of liver pathology in murine schistosomiasis.

Adjustments of γδ T Cells in the Lung of Schistosoma japonicum-Infected C56BL/6 Mice.

Many kinds of lymphocytes are involved in Schistosoma japonicum (S. japonicum) infection-induced disease. γδ T cells comprise a small number of innate lymphocytes that quickly respond to foreign materials. In this study, the role of γδ T cells in the lung of S. japonicum-infected C56BL/6 mice was investigated. The results demonstrated that S. japonicum infection induces γδ T cell accumulation in the lung, expressing higher levels of CD25, MHCII, CD80, and PDL1, and lower levels of CD127 and CD62L (P < 0.05). The intracellular cytokines staining results illustrated higher percentages of IL-4-, IL-10-, IL-21-, and IL-6-producing γδ T cells and lower percentages of IFN-γ-expressing γδ T cells in the lung of infected mice (P < 0.05). Moreover, the granuloma size in lung tissue was significantly increased in Vδ-/- mice (P < 0.05). In the lung of S. japonicum-infected Vδ-/- mice, both type 1 and type 2 immune responses were decreased significantly (P < 0.05). In addition, the expression of CD80 and CD69 on B cells was decreased significantly (P < 0.05), and the SEA-specific antibody was markedly decreased (P < 0.05) in the blood of infected Vδ-/- mice. In conclusion, this study indicates that γδ T cells could adjust the Th2 dominant immune response in the lung of S. japonicum-infected mice.

[Impact of gender on hepatic pathology and antibody - mediated immunity caused by Schistosoma japonicum infection in C57BL/6 mice].

OBJECTIVE: To investigate the effect of gender on hepatic pathology and antibody-mediated immunity in Schistosoma japonicum-infected C57BL/6 mice. METHODS: Female and male C57BL/6 mice were infected with S. japonicum, and the hepatic pathological changes were observed using HE and picrosirius red staining in mice 8 weeks post-infection. The serum specific IgG antibody levels against the soluble adult worm antigen (SWA) and soluble egg antigen (SEA) were measured in mice using enzyme-linked immunosorbent assay (ELISA), and the percentages of follicular helper T (Tfh) cells and regulatory T (Treg) cells were detected in mouse spleen and lymph nodes using flow cytometry. RESULTS: HE staining showed no significant difference in the mean area of a single hepatic egg granuloma between female and male mice 8 weeks post-infection with S. japonicum [(28.050 ± 3.576) × 104 µm2 vs. (26.740 ± 4.093) × 104 µm2; t = 0.241, P = 0.821], and picrosirius red staining revealed no statistical differences between female and male mice in terms of the mean proportion of picrosirius red stained hepatic tissues [(7.667 ± 1.856)% vs. (7.667 ± 1.764)%; t = 0, P = 1] or the mean optical density [(0.023 ± 0.003) vs. (0.027 ± 0.007); t = 0.447, P = 0.678]. ELISA detected no significant differences in the serum IgG antibody levels against SWA [(2.098 ± 0.037) vs. (1.970 ± 0.071); t = 1.595, P = 0.162] or SEA [(3.738 ± 0.039) vs. (3.708 ± 0.043); t = 0.512, P = 0.623] between female and male mice 8 weeks post-infection with S. japonicum. Flow cytometry detected significantly greater percentages of Tfh cells in the spleen [female mice, (8.645 ± 1.356)% vs. (1.730 ± 0.181)%, t = 5.055, P = 0.002; male mice, (8.470 ± 1.161)% vs. (1.583 ± 0.218)%, t = 5.829, P = 0.001] and lymph nodes [female mice, (3.218 ± 0.153)% vs. (1.095 ± 0.116)%, t = 11.040, P < 0.001; male mice, (3.673 ± 0.347)% vs. (0.935 ± 0.075)%, t = 8.994, P = 0.001) of both female and male mice 8 weeks post-infection with S. japonicum than in uninfected mice; however, no significant differences were seen between female and male mice 8 weeks post-infection with S. japonicum in terms of the percentages of Tfh cells in the spleen [(8.645 ± 1.356)% vs. (8.470 ± 1.161)%; t = 0.098, P = 0.925] or lymph nodes [(3.218 ± 0.153)% vs. (3.673 ± 0.347)%; t = 1.332, P = 0.241]. There was no significant difference in the proportion of Treg cells in the spleen of male mice between infected and uninfected mice [(10.060 ± 0.361)% vs. (10.130 ± 0.142)%; t = 0.174, P = 0.867], while a higher proportion of Treg cells was seen in the spleen of female mice 8 weeks post-infection with S. japonicum than in uninfected mice [(10.530 ± 0.242)% vs. (9.450 ± 0.263)%; t = 3.021, P = 0.023]. There was no significant difference in the proportion of Treg cells in the spleen between female and male mice infected with S. japonicum [(10.530 ± 0.242)% vs. (10.060 ± 0.361)%; t =1.077, P = 0.323]. In addition, the proportions of Treg cells were significantly greater in the lymph node of S. japonicum -infected female [(17.150 ± 0.805)% vs. (13.100 ± 0.265)%; t = 4.781, P = 0.003] and male mice [(18.550 ± 0.732)% vs. (12.630 ± 0.566)%; t = 6.402, P = 0.001] than in uninfected mice; however, no significant difference was seen between female and male mice 8 weeks post-infection [(17.150 ± 0.805)% vs. (18.550 ± 0.732)%; t = 1.287, P = 0.246]. CONCLUSIONS: There are no gender-specific hepatic pathological changes or antibody-mediated immunity in C57BL/6 mice post-infection with S. japonicum.

Case Report: Multiple Schistosomiasis Japonica Cerebral Granulomas without Gastrointestinal System Involvement: Report of Two Cases and Review of Literature.

Most schistosomiasis japonica cerebral granulomas reported in the literature have been single and located in the cerebellum, and multiple lesions located in the cerebral hemisphere are uncommon and often misdiagnosed as metastases or gliomas. We describe two rare cases of multiple schistosomiasis japonica cerebral granulomas. Laboratory examinations and cerebrospinal fluid were normal. Parasite eggs were not detected in the stool. No positive findings were detected in the abdominal ultrasonography or chest radiography. Magnetic resonance revealed two intensive patchy lesions in the cerebral hemisphere and surrounded by a large area of edema in both of our patients. Both were misdiagnosed as glioma or metastatic carcinoma before operation. Pathological examination confirmed that the diagnosis was schistosomiasis japonica cerebral granuloma. Praziquantel and dexamethasone were administered. Both patients are alive, symptom-free, and without evidence of recurrence. Combining our date with other literature reports, we summarize the possible mechanism, reasons for misdiagnosis, radiological characteristics, surgical treatment, and postoperative management of schistosomiasis japonica cerebral granuloma, which can be used for clinical reference and to improve our knowledge of schistosomiasis japonica cerebral granuloma.

Genome assembly and transcriptome analysis provide insights into the antischistosome mechanism of Microtus fortis.

Microtus fortis is the only mammalian host that exhibits intrinsic resistance against Schistosoma japonicum infection. However, the underlying molecular mechanisms of this resistance are not yet known. Here, we perform the first de novo genome assembly of M. fortis, comprehensive gene annotation analysis, and evolution analysis. Furthermore, we compare the recovery rate of schistosomes, pathological changes, and liver transcriptomes between M. fortis and mice at different time points after infection. We observe that the time and type of immune response in M. fortis are different from those in mice. M. fortis activates immune and inflammatory responses on the 10th day post infection, such as leukocyte extravasation, antibody activation, Fc-gamma receptor-mediated phagocytosis, and the interferon signaling cascade, which play important roles in preventing the development of schistosomes. In contrast, an intense immune response occurrs in mice at the late stages of infection and could not eliminate schistosomes. Infected mice suffer severe pathological injury and continuous decreases in cell cycle, lipid metabolism, and other functions. Our findings offer new insights into the intrinsic resistance mechanism of M. fortis against schistosome infection. The genome sequence also provides the basis for future studies of other important traits in M. fortis.

Analysis of CT characteristics in the diagnosis of Schistosoma japonicum associated appendicitis with clinical and pathological correlation: a diagnostic accuracy study.

PURPOSE: To clarify unique non-contrast CT (NCCT) characteristics for early recognition of Schistosomal associated appendicitis (SAA) differentiating from Non-schistosomal associated appendicitis (NSA). MATERIAL AND METHODS: Clinical and pathological data of 50 cases with SAA and 60 cases with NSA who underwent emergency appendectomy were retrospectively compared to pre-surgical NCCT features such as direct and indirect signs of acute appendicitis as well as appendicoliths, colon calcifications as diagnostic criteria. Statistical methods such as Chi-square (χ2), t-tests, Principal component analysis (PCA), Binary Logistic regression (LR) and Factor Analysis (FA) were utilized to observe differences and isolate recognizable CT features of SAA. Pre and post hoc diagnostic performance of all criteria was calculated as sensitivity, specificity, and the Odds Ratio (OR). RESULTS: Age > 50 years, diameter > 13 mm, pneumatosis, peri appendiceal abscess, focal wall defect, perforation; Orbital, linear and point types of appendicular wall calcifications; sigmoid colon and cecal curvilinear calcifications were observed as unique characteristics with a sensitivity of 84-95% and specificity of 91-98% in predicting SAA by OR of 6.2 times. Pre and post hoc hypothetical analysis did not show any significance for all other factors. CONCLUSION: Factors such as elderly age, CT features such as larger appendicular diameter, appendicular wall calcifications along with sigmoid colon, and cecal calcifications, signs of perforation or abscess are characteristic for early recognition of SAA.

Improvement of Mitochondrial Activity and Fibrosis by Resveratrol Treatment in Mice with Schistosoma japonicum Infection.

Schistosomiasis caused by Schistosoma japonicum is a major parasitic disease in the People's Republic of China. Liver fibrosis is the main pathological mechanism of schistosomiasis, and it is also the major lesion. The common drug used for its treatment, praziquantel (PZQ), does not have a marked effect on liver fibrosis. Resveratrol (RSV), which is an antioxidant, improves mitochondrial function and also attenuates liver fibrosis. The combination of PZQ and RSV has been found to have a synergistic antischistosomal effect on Schistosoma mansoni; additionally, the activity of PZQ is enhanced in the presence of RSV. Here, we examine the therapeutic effects of RSV on the S. japonicum infection in a mouse model, and we investigate RSV as a novel therapeutic agent for mitochondrial function and schistosomiasis-associated liver fibrosis (SSLF). Mitochondrial membrane potential was examined using flow cytometry analysis. The expression of the mitochondrial biogenesis genes PGC-α and fibrosis-associated genes collagen I, collagen III and α-SMA were examined using western blot analysis. Fibrosis-associated histological changes were examined using Masson trichrome staining. Additionally, the effects of RSV on S. japonicum adult worms were examined using scanning electron microscopy and transmission electron microscopy. RSV treatment improved mitochondrial function by increasing membrane potential and increasing PGC-α expression (mitochondrial biogenesis). Further, RSV attenuated liver injury, including liver scarring, by decreasing collagen deposition and the extent of fibrosis, based on the decrease in expression of the fibrosis-related genes. RSV also decreased the adult worm count and caused considerable physical damage to the worm. These results indicate that RSV upregulates mitochondrial biogenesis and inhibits fibrosis. RSV may have potential as a therapeutic target for the treatment of fibrosis in schistosomiasis.

Soluble egg antigen of Schistosoma japonicum induces pyroptosis in hepatic stellate cells by modulating ROS production.

BACKGROUND: Inflammation-induced dysfunction of hepatic stellate cells (HSCs) is involved in schistosomiasis-associated liver fibrosis, and soluble egg antigen (SEA) is a crucial pathogen-associated molecular pattern associated with liver injury in schistosomiasis. In addition, numerous studies have shown that caspase-1-mediated pyroptosis participates in the development of multiple inflammation-related diseases. However, whether pyroptotic cell death of HSCs is involved in SEA-mediated liver damage is not well understood. METHODS: Primary cultured HSCs and Schistosoma japonicum-infected mouse liver tissue were analysed for histological changes and caspase-1 activation, and the role of pyroptosis in the mechanisms underlying SEA-induced HSC death was investigated. Accumulation of reactive oxygen species (ROS) in infected livers and SEA-stimulated HSCs was measured by flow cytometry and immunofluorescence. RESULTS: Caspase-1 activity was elevated in both liver tissues and HSCs of S. japonicum-infected mice. Furthermore, SEA stimulation increased the proportion of pyroptotic HSCs, as shown by lactate dehydrogenase (LDH) release assays and by flow cytometric analysis of propidium iodide (PI) and caspase-1 double staining in cells. In addition, ROS generation was elevated in infected liver tissues and SEA-stimulated HSCs, and ROS inhibition downregulated SEA-induced caspase-1 activation and pyroptosis in HSCs. CONCLUSIONS: Our present study demonstrates that pyroptotic cell death in HSCs induced by SEA via ROS-mediated caspase-1 activation may serve as a significant mechanism to initiate the inflammatory response and thereby exacerbate liver injury during S. japonicum infection.

Recombinant Sj16 protein with novel activity alleviates hepatic granulomatous inflammation and fibrosis induced by Schistosoma japonicum associated with M2 macrophages in a mouse model.

BACKGROUND: Potent granulomatous inflammation responses induced by schistosome eggs and resultant fibrosis are the primary causes of morbidity in schistosomiasis. Recombinant Sj16 (rSj16), a 16-kDa protein of Schistosoma japonicum produced in Escherichia coli, has been demonstrated to have novel immunoregulatory effects in vivo and in vitro. Thus, this study investigated the anti-inflammatory and anti-fibrotic effects of rSj16 treatment in S. japonicum-infected mice and demonstrated the immune modulation between the schistosome and the host. METHODS: Schistosoma japonicum infected mice were treated with the rSj16 protein and Sj16 peptide at different time points post-infection to assess their efficacy at the optimal time point. Sj16 peptide and/or Praziquantel (PZQ) treatments were initiated at week 5 post-infection to compare the therapeutic efficacy of each regimen. Hepatic granulomatous inflammation, fibrosis and cytokine production (pro-inflammatory, Th1, Th2, Th17 and regulatory cytokines IL-10) were detected. Moreover, M2 macrophages were measured to illuminate the mechanisms of Sj16. RESULTS: The rSj16 protein and Sj16 peptide had significant protective effects in S. japonicum-infected mice, as shown by decreased granuloma formation, areas of collagen deposition and inhibition of pro-inflammatory Th1, Th2 and Th17 cytokine production. These protective activities were more obvious when animals were treated with either the Sj16 protein or peptide at early stages post-infection. Interestingly, the combined treatment of PZQ and Sj16 was more effective and upregulated IL-10 production than administration of PZQ alone in infected mice. Furthermore, the Sj16 treatment alleviated the pathological effects associated with activated M2 macrophages. CONCLUSIONS: This study demonstrates the anti-inflammatory and anti-fibrotic effects of rSj16 in schistosomiasis. Therefore, the combination of rSj16 with PZQ could be a viable and promising therapeutic strategy for schistosomiasis. In addition, this investigation provides additional information on schistosome-mediated immune modulation and host-parasite interactions.