Schistosoma Japonicum-infected Mice Research Articles

Single-cell RNA sequencing to dissect the immunological network of liver fibrosis in Schistosoma japonicum-infected mice.

Liver fibrosis is a poor outcome of patients with schistosomiasis, impacting the quality of life and even survival. Eggs deposited in the liver were the main pathogenic factors of hepatic fibrosis in Schistosomiasis japonica. However, the mechanism of hepatic fibrosis in schistosomiasis remains not well defined and there is no effective measure to prevent and treat schistosome-induced hepatic fibrosis. In this study, we applied single-cell sequencing to primarily explore the mechanism of hepatic fibrosis in murine schistosomiasis japonica (n=1) and normal mouse was served as control (n=1). A total of 10,403 cells were included in our analysis and grouped into 18 major cell clusters. Th2 cells and NKT cells were obviously increased and there was a close communication between NKT cells and FASLG signaling pathway. Flow cytometry analysis indicated that the expression of Fasl in NKT cells, CD8+ T cell and NK cell were higher in SJ groups. Arg1, Retnla and Chil3, marker genes of alternatively activated macrophages (M2), were mainly expressed in mononuclear phagocyte(1) (MP(1)), suggesting that Kupffer cells might undergo M2-like polarization in fibrotic liver of schistosomiasis. CXCL and CCL signaling pathway analysis with CellChat showed that Cxcl16-Cxcr6, Ccl6-Ccr2 and Ccl5-Ccr5 were the most dominant L-R and there were close interactions between T cells and MPs. Our research profiled a preliminary immunological network of hepatic fibrosis in murine schistosomiasis japonica, which might contribute to a better understanding of the mechanisms of liver fibrosis in schistosomiasis. NKT cells and CXCL and CCL signaling pathway such as Cxcl16-Cxcr6, Ccl6-Ccr2 and Ccl5-Ccr5 might be potential targets to alleviate hepatic fibrosis of schistosomiasis.

FXR deficiency in hepatocytes disrupts the bile acid homeostasis and inhibits autophagy to promote liver injury in Schistosoma japonicum-infected mice.

BackgroundSchistosomiasis, with 250 million people affected, is characterized by its serious hepatic inflammatory response and fibrosis formation, which could lead to dangerous complications, such as portal hypertension, splenomegaly and even ascites. But until now, the pathogenesis of schistosomiasis remains largely unknown. Farnesoid X Receptor (FXR), a bile acid-activated nuclear transcription factor mainly expresses in hepatocytes in the liver, can regulate liver diseases by controlling bile acid metabolism.Methodology/Principal findingsIn this study, we found that the expression of FXR was decreased in the liver of infected mice as shown by western blot and RT-qPCR assays. Furthermore, hepatocyte-specific FXR-deficient mice (FXRflox/floxAlbCre, FXR-HKO) were generated and infected with ~16 cercariae of S. japonicum for five weeks. We found that FXR deficiency in hepatocytes promoted the progression of liver injury, aggravated weight loss and death caused by infection, and promoted inflammatory cytokines production, such as IL-6, IL-1β, TNF-α, IL-4, IL-10, and IL-13. Surprisingly, hepatic granulomas and fibrosis were not affected. In addition, using UPLC-MS/MS spectrometry, it was found that S. japonicum infection resulted in elevated bile acids in the liver of mice, which was more obvious in FXR-deficient mice. Meanwhile, autophagy was induced in littermate control mice due to the infection, but it was significantly decreased in FXR-HKO mice.Conclusions/SignificanceAll these findings suggest that FXR deficiency in hepatocytes disrupts bile acid homeostasis and inhibits autophagy, which may aggravate the damages of hepatocytes caused by S. japonicum infection. It highlights that FXR in hepatocytes plays a regulatory role in the progression of schistosomiasis.

MULT1-Encoding DNA Alleviates Schistosomiasis-Associated Hepatic Fibrosis via Modulating Cellular Immune Response.

PurposeIn schistosomiasis-associated hepatic fibrosis, the role of murine UL16-binding protein-like transcript 1 (MULT1), the strongest ligand of natural killer group 2-member D receptor (NKG2D), remains unclear. Here, Schistosoma japonicum-infected mice administered with MULT1-encoding DNA were used to test MULT1 as a potential therapy for schistosomiasis-associated hepatic fibrosis and explore relevant mechanisms.Materials and MethodsA recombinant plasmid encoding MULT1 (p-rMULT1) was constructed and administered to Schistosoma japonicum-infected BALB/c mice via hydrodynamic tail vein injection. Egg granulomas in liver, hepatic fibrosis biomarkers and levels of cytokines were investigated. Comparisons of CD4+ T, CD8+ T, NK and NKT proportions as well as their phenotype were performed not only between Schistosoma infected, p-rMULT1 treated group and Schistosoma infected, backbone plasmid pEGFP-N1 treated group but also between infected, nontreated group and health control group.ResultsReduced area of granuloma formation and fibrosis around single eggs, downregulated expression of collagen I, α-smooth muscle actin, TGF-β and IL-10, and upregulated expression of IFN-γ, were observed in the livers of p-rMULT1 treated mice. p-rMULT1 treatment improved Schistosoma infection impacted immune microenvironment by modulating proportion of CD4+ T CD8+ T, natural killer (NK) and NKT cells, enhancing expression of NKG2D, in lymphocytes, and augmenting IFN-γ secretion by CD4+ T, CD8+ T, NK and NKT cells, as well as partially reversing some other phenotype changes of lymphocytes.ConclusionTo the best of our knowledge, we provided the first in vivo evidence that MULT1 is a favorable anti-fibrosis factor in the context of schistosomiasis. The inhibitory effect of MULT1 overexpression on schistosomiasis associated with hepatic fibrosis may result from augmenting the proportion and function of NKG2D-expressing immune cells, and from enhancing NK- and T-cell activation, as well as regulating the helper T (Th)1/Th2 balance.

Host liver-derived extracellular vesicles deliver miR-142a-3p induces neutrophil extracellular traps via targeting WASL to block the development of Schistosoma japonicum

Schistosomiasis is an important neglected tropical disease. Interactions between the host immune system and schistosomes are complex. Neutrophils contribute to clearance of large pathogens primarily by releasing neutrophil extracellular traps (NETs). However, the functional role of NETs in clearing schistosomes remains unclear. Herein, we report that extracellular vesicles (EVs) derived from the liver of Schistosoma japonicum-infected mice (IL-EVs) induce NET release by delivering miR-142a-3p to target WASL and block the development of S.japonicum. WASL knockout accelerated the formation of NETs that blocked further development of S.japonicum. miR-142a-3p and NETs upregulated the expression of CCL2, which recruits macrophages that block S.japonicum development. However, S.japonicum inhibited NET formation in wild-type mice by upregulating host interleukin-10 (IL-10) expression. In contrast, in WASL knockout mice, IL-10 expression was downregulated, and S.japonicum-mediated inhibition of NET formation was significantly reduced. IL-EV-mediated induction of NET formation is thus an anti-schistosome response that can be counteracted by S.japonicum. These findings suggest that IL-EV-mediated induction of NET formation plays a key role in schistosome infection and that WASL is a potential therapeutic target in schistosomiasis and other infectious diseases.

Characterization of MicroRNA Cargo of Extracellular Vesicles Isolated From the Plasma of Schistosoma japonicum-Infected Mice.

Schistosoma is a genus of parasitic trematodes that undergoes complex migration in final hosts, finally developing into adult worms, which are responsible for egg production and disease dissemination. Recent studies documented the importance of extracellular vesicles (EVs) in the regulation of host-parasite interactions. Herein, we investigated the microRNA (miRNA) profiles of EVs isolated from host plasma at different stages of Schistosoma japonicum infection (lung stage: 3 days post-infection (dpi), and liver stages: 14 and 21 dpi) to identify miRNA cargo potentially involved in the pathogenesis and immune regulation of schistosomiasis. Characterization of the isolated plasma EVs revealed their diameter to be approximately 100 nm, containing typical EV markers such as Hsp70 and Tsg101. Deep sequencing analysis indicated the presence of 811 known and 15 novel miRNAs with an increasing number of differential miRNAs from the lung stage (27 miRNAs) to the liver stages (58 and 96 miRNAs at 14 and 21 dpi, respectively) in the plasma EVs of infected mice compared to EVs isolated from the uninfected control. In total, 324 plasma EV miRNAs were shown to be co-detected among different stages of infection and the validation of selected miRNAs showed trends of abundance similar to deep sequencing analysis. For example, miR-1a-3p and miR-122-5p showed higher abundance, whereas miR-150-3p and miR-126a showed lower abundance in the plasma EVs of infected mice at 3, 14, and 21 dpi as compared to those of uninfected mice. In addition, bioinformatic analysis combined with PCR validation of the miRNA targets, particularly those associated with the immune system and parasitic infectious disease, indicated a significant increase in the expression of Gbp7and Ccr5 in contrast to the decreased expression of Fermt3, Akt1, and IL-12a. Our results suggested that the abundance of miRNA cargo of the host plasma EVs was related to the stages of Schistosoma japonicum infection. Further studies on the roles of these miRNAs may reveal the regulatory mechanism of the host-parasite interaction. Moreover, the differentially abundant miRNA cargo in host EVs associated with S. japonicum infection may also provide valuable clues for identifying novel biomarkers for schistosomiasis diagnosis.

Bacillus subtilis Attenuates Hepatic and Intestinal Injuries and Modulates Gut Microbiota and Gene Expression Profiles in Mice Infected with Schistosoma japonicum

Parasitic infection can induce pathological injuries and impact the gut microbiota diversity and composition of the host. Bacillus subtilis is a nonpathogenic and noninvasive probiotic bacterium for humans and other animals, playing an important role in improving the host immune system’s ability to respond to intestinal and liver diseases and modulating gut microbiota. However, whether B. subtilis can impact biological functions in Schistosoma japonicum–infected mice is unclear. This study used oral administration (OA) of B. subtilis to treat mice infected with S. japonicum. We evaluated changes in the gut microbiota of infected mice using 16 S rRNA gene sequencing and differentially expressed gene profiles using transcriptome sequencing after OA B. subtilis. We found that OA B. subtilis significantly attenuated hepatic and intestinal pathological injuries in infected mice. The gut microbiota of mice were significantly altered after S. japonicum infection, while OA B. subtilis remodel the diversity and composition of gut microbiomes of infected mice. We found that the S. japonicum–infected mice with OA B. subtilis had an overabundance of the most prevalent bacterial genera, including Bacteroides, Enterococcus, Lactobacillus, Blautia, Lachnoclostridium, Ruminiclostridium, and Enterobacter. Transcriptomic analysis of intestinal tissues revealed that OA B. subtilis shaped the intestinal microenvironment of the host responding to S. japonicum infection. Differentially expressed genes were classified into KEGG pathways between S. japonicum–infected mice and those without included cell adhesion molecules, intestinal immune network for IgA production, hematopoietic cell lineage, Fc epsilon RI signaling pathway, Th1 and Th2 cell differentiation, Th17 cell differentiation, calcium signaling pathway, Fc gamma R-mediated phagocytosis, chemokine signaling pathway, phospholipase D signaling pathway, NF-kappa B signaling pathway, B cell receptor signaling pathway, pancreatic secretion, and phagosome. In conclusion, our findings showed that OA B. subtilis alleviates pathological injuries and regulates gene expression, implying that B. subtilis supplementation may be a potential therapeutic strategy for schistosomiasis. Our study may highlight the value of probiotics as a beneficial supplementary therapy during human schistosomiasis, but further studies are needed.

Therapeutic inhibition of miR-802 protects against obesity through AMPK-mediated regulation of hepatic lipid metabolism.

Background: The host-parasite relationship is based on subtle interplay between parasite survival strategies and host defense mechanisms. It is well known that helminth infection, which afflicts more than one billion people globally, correlates with a decreased prevalence of obesity. Dissecting the underlying mechanisms can provide new targets for treating obesity from the host-parasite interaction perspective.Methods: C57BL/6 mice received a normal or high-fat diet (HFD) with or without Sjp40 (one main component of schistosome-derived soluble egg antigens) treatment. Both the loss and gain-of-function experiments by the inhibitor suppression and lentivirus treatment of miR-802 were utilized to elucidate the role of miR-802/AMPK axis in host lipid metabolism. Hepatocyte lipogenesis assay and metabolic parameters were assessed both in vivo and in vitro. The potential interactions among Sjp40, CD36, miR-802, Prkab1, and AMPK were clarified by pull-down, miRNA expression microarray, quantitative RT-PCR, dual-luciferase reporter assay, and western blotting analysis.Results: We showed a link between decreased miR-802 and impaired lipid metabolism in Schistosoma japonicum infected mice. The decreased miR-802 promotes murine Prkab1 or human Prkaa1 expression, respectively, which increases levels of phosphorylated AMPK, resulting in a decrease in hepatic lipogenesis. Also, injection with schistosome-derived soluble egg antigens (SEA) attenuated metabolism. We demonstrated that Sjp40 as a main component of SEA interacted with CD36 on hepatocytes to inhibit miR-802, resulting in the activation of AMPK pathway and subsequent attenuation of lipogenesis.Collectively: Our study reveals the significant role of miR-802/AMPK axis in hepatic lipid metabolism and identifies the therapeutic potential of Sjp40 in treating obesity-related fatty liver.

Schistosoma japonicum-infected sentinel mice: Surveillance and spatial point pattern analysis in Hubei province, China, 2010–2018

ObjectivesProgress in national schistosomiasis control in China has successfully reduced disease transmission in many districts. However, a low transmission rate hinders conventional snail surveys in identifying areas at risk. In this study, Schistosoma japonicum-infected sentinel mice surveillance was conducted to identify high-risk areas of schistosomiasis transmission in Hubei province, China. MethodsThe risk of schistosomiasis transmission was assessed using sentinel mice monitoring in Hubei province from 2010 to 2018. Field detections were undertaken in June and September, and the sentinel mice were kept for approximately 35 days in a laboratory. They were then dissected to determine whether schistosome infection was present. Ripley's K-function and kernel density estimation were applied to analyze the spatial distribution and positive point pattern of schistosomiasis transmission. ResultsIn total, 190 sentinel mice surveillance sites were selected to detect areas of schistosomiasis infection from 2010 to 2018, with 29 (15.26%) sites showing infected mice. Of 4723 dissected mice, 256 adult worms were detected in 112 infected mice. The infection rate was 2.37%, with an average of 2.28 worms detected per infected mouse. Significantly more infected mice were detected in the June samples than in the September samples (χ2=12.11, p<0.01). Ripley's L(d) index analysis showed that, when the distance was ≤34.52km, the sentinel mice infection pattern showed aggregation, with the strongest aggregation occurring at 7.86km. Three hotspots were detected using kernel density estimation: at the junction of Jingzhou District, Gong’an County, and Shashi District in Jingzhou City; in Wuhan City at the border of the Huangpi and Dongxihu Districts, and in the Hannan and Caidian Districts. ConclusionThe results showed that sentinel mice surveillance is useful in identifying high-risk areas, and could provide valuable information for schistosomiasis prevention and control, especially concerning areas along the Yangtze River, such as the Fu-Lun, Dongjing-Tongshun, and Juzhang River basins.

Polysaccharide from Phellinus igniarius alleviates oxidative stress and hepatic fibrosis in Schistosoma japonicum-infected mice

To evaluate the role of polysaccharide from Phellinus igniarius (PPI) in the improvement of oxidative stress, hepatic granuloma and hepatic fibrosis in Schistosoma japonicum-iniected in mice. The mouse model of schistosomiasis was established by S. japonicum cercariae infection via the abdomen. Balb/c mice were randomly assigned into 5 groups, including the healthy control group (Group A), infection control group (Group B), PPI treatment group (Group C), praziquantel treatment group (Group D) and PPI-praziquantel combination group (Group E), of 10 mice in each group. Each mouse in groups B, C, D and E was infected with (30 ± 2) S. japonicum cercariae. Then, mice in groups D and E were given praziquantel by gavage at a dose of 500 mg/kg for successive two days on day 42 post-infection, while mice in groups C and E were given PPI by gavage at a dose of 400 mg/kg for successive 30 days on day 42 post-infection. Histopathological changes of hepatic tissues were observed using hematoxylin-eosin (HE) staining, and serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hyaluronic acid (HA), laminin (LN) were determined, while the activities of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), glutathione reductase (GSH-R) and glutathione (GSH) were detected in Mouse liver homogenates. The expression of transforming growth factor-beta (TGF-β) and alpha-smooth muscle actin (α-SMA) was quantified in hepatic tissues using immunohistochemistry, and the Nrf2 and Gsta4 gene expression was quantified using quantitative real-time PCR (qPCR) assay. Untreated mice presented typical pathological changes of schistosomal hepatic disorders, while PPI treatment effectively alleviated hepatic egg granulomas and collagen deposition. S. japonicum infection resulted in aggravation of hepatic lipid peroxidation, induction of oxidative stress, elevated serum MDA level and a reduction in the activity of GSH and antioxidant enzymes activities in mice. As compared to infected but untreated mice, PPI treatment suppressed hepatic lipid peroxidation, increased the GSH activity and restored the activity of antioxidant enzymes. In addition, PPI treatment inhibited the TGF-β signaling pathway and up-regulated the Nrf2 and Gsta4 gene expression. PPI plays a critical role in the treatment of schistosomiasis-induced hepatic fibrosis. It may improve oxidative stress damages through up-regulating Nrf2 and Gsta4 gene expression, thereby suppressing the development of hepatic egg granulomas and hepatic fibrosis.

NLRP3 inflammasome activation from Kupffer cells is involved in liver fibrosis of Schistosoma japonicum-infected mice via NF-\u03baB

BackgroundNOD-like receptor protein 3 (NLRP3) inflammasome was reported as expressed in schistosomiasis-induced liver fibrosis (SSLF). We used an NLRP3 inflammasome inhibitor, MCC950, to investigate whether it inhibited liver fibrosis, and explored the preliminary molecular mechanism.MethodsBALB/c mice were infected with 15 cercariae through the abdominal skin. They received intraperitoneal injections of MCC950 on the day of infection and at day 22 post-infection. We examined their SSLF phenotype and the effect on liver fibrosis, primary Kupffer cells (KCs), and HSCs. Human hepatic stellate cell lines (human LX-2 cells) were treated with soluble egg antigen (SEA) released from the eggs. We then determined the expression of NLRP3 inflammasome and liver fibrosis-associated markers, liver granuloma and ALT/AST.ResultsNLRP3 inflammasome expression in the liver was significantly increased, and eosinophilic granuloma and collagen deposition were found around the eggs in mice infected for 56 days. Additionally, IL-1β, ALT/AST in plasma, and NF-κB in liver tissue and in KCs were all greatly significantly increased. The above-mentioned indicators were largely reduced in mice treated with MCC950 on the day of infection. In vitro, lipopolysaccharide (LPS)/SEA could induce LX-2 cells to express NLRP3 and fibrosis markers, and the SEA-treated group was reversed by MCC950. Furthermore, NLRP3 inflammasome and liver fibrosis-associated markers were both increased in the primary KCs and HSCs isolated from infected mice. However, this effect was not observed in the same cells from the mice treated with MCC950 on the day of infection. Contrary to the aforementioned results, MCC950 treatment at day 22 post-infection aggravated this process. Surprisingly, NLRP3 inflammasome was involved in liver fibrosis mostly from KCs.ConclusionsMCC950 acts dually on SSLF pathology and fibrosis in infected mice. Although MCC950 treatment improved SSLF on the day of infection, it exacerbated the pathological effects at day 22 post-infection. These dual effects were mediated via NF-κB. Moreover, NLRP3 inflammasome mainly came from KCs. Our results suggest that blocking NLRP3 on the day of infection may prove to be a promising direction in preventing SSLF.

Study on role of TIGIT signal in Th1/Th2 balance in Schistosoma japonicum-infected mice

To investigate the role of TIGIT signal in Th1/Th2 balance in the process of Schistosoma japonicum infection. Male C57BL/6 mice were infected with cercariae of S. japonicum, and normal uninfected mice served as the controls. The percentages of TIGIT+ cells, Ki67+CD3+CD4+TIGIT+ cells, Ki67+CD3+CD4+TIGIT- cells, IFN-γ+CD3+CD4+TIGIT+ cells, IFN-γ+CD3+CD4+TIGIT- cells, IL-4+CD3+CD4+TIGIT+ cells and IL-4+CD3+CD4+TIGIT- cells were evaluated in mouse spleen by flow cytometry. The proportion of TIGIT+CD4+ T cells was higher in the spleen of S. japonicum-infected mice than in the normal uninfected mice (29.30%±0.70% vs. 3.09%±0.50%; t = 8.834, P < 0.01) . However, no significant difference in the percentages of TIGIT+ CD8+ T cells between the infection group and normal controls (3.61%±0.26% vs. 3.58%±0.16%; t = 0.108, P > 0.05), and no significant difference was detected in the percentages of TIGIT+ cells in non-T cells between the infection group and controls (1.86%±0.19% vs.1.37%±0.17%; t = 1.931, P > 0.05) . In addition, the proportion of Ki67 in the TIGIT+ cells was higher than that in the TIGIT- cells (17.03%±0.64% vs. 6.59%±0.37%; t = 14.09, P < 0.01) . The Th2/Th1 ratio was higher in the TIGIT+CD4+ T cells than in the TIGIT-CD4+ T cells (39.28%±3.75% vs. 11.79%±1.64%; t = 6.721, P < 0.01) . The TIGIT signaling may be involved in the development of Th2 responses in the mice infected with S. japonicum.

Heat shock protein 47 effects on hepatic stellate cell-associated receptors in hepatic fibrosis of Schistosoma japonicum-infected mice.

The study aimed to explore the regulation of heat shock protein 47 (HSP47) on expressions of receptors associated with hepatic stellate cell (HSC) in liver fibrosis mouse models induced by Schistosoma japonicum (S. japonicum). Mouse fibroblasts (NIH/3T3) were transfected with HSP47 shRNA plasmid by lipofectamine transfection, and experimental fibrosis in HSCs was studied in S. japonicum mouse models treated with HSP47 shRNA in vivo. HSP47 expression was assessed using Western blot and real-time PCR. Flow cytometry was adopted to determine the expression of cell membrane receptors. HSP47-shRNA could markedly down-regulate the expression of collagen (Col1a1 and Col3a1). The expressions of HSP47, endothelin receptor A (ETAR) and endothelin receptor B (ETBR) significantly increased in the liver tissue of infected mice. However, the expressions of ETAR and HSP47 and ETBR remarkably decreased after the administration of HSP47 shRNA in vitro and in vivo. ETAR and ETBR levels were found to be positively correlated with HSP47 expression. HSP47 might exert influence on liver fibrosis via the regulation of ETAR and ETBR.

Surveillance results and risk analysis of Schistosoma japonicum-infected sentinel mice in key water regions in Hubei Province in 2016

Objective To investigate the water infectivity in key water regions, and analyze the transmission risk of schistosomiasis in suspicious and high-risk environments in Hubei Province in 2016. Methods Schistosome-endemic areas of the Yangtze River, the Hanbei River and the Fu River were chosen as the surveillance and forecast sites. The water infectivity was detected by using the sentinel mice during the flood season. The infection status of residents in the villages around the surveillance sites and the activities of human beings and domestic animals were surveyed. The emergency response system was initiated when the water infectivity areas were detected. Results From May to June, among the ten surveillance sites of the first batch, two positive spots with infected mice were found, accounting for 20%. All the recovered mice (totally 200) were dissected: five mice were infected, with a total infection rate of 2.5%. Totally five schistosome adult worms were collected, with mean worm burden of 1 worm per infected mouse. The site with cercariae-infected water body started the emergency response and no epidemic occurred. From August to September, among the eight surveillance sites of the second batch, the recovered mice (totally 160) were dissected, and no infected sentinel mice were found. Conclusion The sentinel mice method plays an important role in analyzing the schistosomiasis transmission risk in Hubei Province.

Salmonella typhimurium Infection Reduces Schistosoma japonicum Worm Burden in Mice

Coinfection of microorganisms is a common phenomenon in humans and animals. In order to further our understanding of the progress of coinfection and the possible interaction between different pathogens, we have built a coinfection mouse model with Schistosoma japonicum and Salmonella typhimurium, and used this model to investigate the systemic metabolic and immune responses using NMR-based metabonomics and immunological techniques. Our results show that Salmonella typhimurium (ATCC14028) infection reduces the number of adult schistosomal worms and eggs, relieves symptoms of schistosomiasis and also abates the mortality of mice infected by Schistosoma japonicum. In addition, Salmonella typhimurium infection counteracts the metabolic disturbances associated with schistosomiasis, which was reflected by the reverted levels of metabolites in coinfected mice, compared with the Schistosoma japonicum infected mice. Furthermore, immune analyses also indicate that shift of the immune response to different pathogens is a result of indirect interactions between Schistosoma japonicum and Salmonella typhimurium within the host. Salmonella typhimurium infection can ameliorate Schistosoma japonicum-caused schistosomiasis in BALB/c mice, which is most likely due to inverse immune polarization. Our work provides an insight into coinfection between Schistosoma japonicum and Salmonella typhimurium, and may further contribute to the development of new tools for controlling Schistosoma japonicum-associated diseases.

Differential pulmonic NK and NKT cell responses in Schistosoma japonicum-infected mice.

Natural killer cells (NK cells) and natural killer T cells (NKT cells) play a role in anti-infection, anti-tumor, transplantation immunity, and autoimmune regulation. However, the role of NK and NKT cells during Schistosoma japonicum (S. japonicum) infection has not been widely reported, especially regarding lung infections. The aim of this study was to research the NK and NKT cell response to S. japonicum infection in the lungs of mice. Using immunofluorescent histological analysis, NK and NKT cells were found near pulmonary granulomas. Moreover, flow cytometry revealed that the percentage and number of pulmonic NK cells in S. japonicum-infected mice were significantly increased (P < 0.05). However, the percentage and cell number of NKT cells were decreased compared to those of normal mice (P < 0.05). The expression of CD69 on pulmonic NK and NKT cells was increased after infection (P < 0.05), and CD25 expression increased only on NKT cells (P < 0.05). Intracellular cytokine staining showed a higher percentage of IFN-γ+ and lower percentage of IL-5+ pulmonic NK cells (P < 0.05) compared to controls. However, the percentage of IL-17+, IL-10+, and IL-5+ pulmonic NKT cells significantly increased (P < 0.05). Additionally, there was a significant decrease in NKG2A/C/E (CD94) expression and an increase of NKG2D (CD314) expression on pulmonic NKT cells (P < 0.05), which might serve as a mechanism for NKT cell activation during S. japonicum infection.

Antischistosomal activity of hederacochiside C against Schistosoma japonicum harbored in experimentally infected animals

The present study was undertaken to investigate whether hederacochiside C (HSC) possesses antischistosomal effects and anti-inflammatory response activities in Schistosoma japonicum-infected mice. Different concentrations of HSC were administrated to the mice infected by schistosomula or adult worm by intravenous injection twice a day for five consecutive days. The total worm burden, female worm burden, and the egg burden in liver of mice treated with 400 mg/kg HSC were fewer than those in non-treated ones. Murine immune responses following HSC treatment were investigated using enzyme-linked immunosorbent assays (ELISA). Our results indicated that 200 mg/kg HSC could reduce the expression of IgG, tumor necrosis factor (TNF)-α, interleukin (IL)-4 and IL-17 in comparison to infected group, exhibiting best immunomodulatory effects. In addition, scanning electron microscopical examination revealed that male worms treated with HSC lost their normal surface architecture since its surface showed extensive swelling, erosion, and peeling in tegumental regions. Remarkable amelioration was noticed in histopathological investigations, and 200 mg/kg HSC treatment could reduce the size of granulomatous inflammatory infiltrations in the liver which was reflected in nearly normalization of liver architecture. These results suggested that HSC had potential antischistosomal activity and provided a basis for subsequent experimental.

Hypoxia-Inducible Factor-1alpha and MAPK Co-Regulate Activation of Hepatic Stellate Cells upon Hypoxia Stimulation

BackgroundHepatic stellate cell (HSC) plays a key role in pathogenesis of liver fibrosis. During liver injury, hypoxia in local micro-environment is inevitable. Hif-1α is the key transcriptional regulation factor that induces cell’s adaptive responses to hypoxia. Recently, it was reported that MAPK is involved in regulation of Hif-1α activity.AimsTo explore whether Hif-1α regulates HSC activation upon hypoxia, and whether MAPK affects Hif-1α-regulated signaling cascades, thus providing new targets for preventing liver fibrosis.MethodsHif-1α expression in livers of Schistosoma japonicum infected BALB/c mice was detected with western blot and immunohistochemistry. A rat cell line of HSC, HSC-T6, was cultured in 1% oxygen. HSC activation, including F-actin reorganization, increase of vimentin and α-SMA, was detected with western blot or immunocytochemistry. Cells were transfected with specific siRNA to Hif-1α, expression of activation markers, transcription of fibrosis-promoting cytokines, secretion of collagen I were detected with western blot, Real Time PCR and ELISA. Lysate from HSC-T6 cells pretreated with PD98059, a specific MEK1 pharmacological inhibitor, was subjected to detect Hif-1α ubiquitination and nuclear translocation with western blot and immunoprecipitation.Results and ConclusionsHif-1α apparently increased in liver tissues of Schistosoma japonicum infected mice. 1% O2 induced F-actin reorganization, increase of Hif-1α, vimentin and α-SMA in HSC-T6 cells. Hif-1α Knockdown inhibited HSC-T6 activation, transcription of IL-6, TGF-β and CTGF and secretion of collagen I from HSC-T6 cells upon hypoxia. Inhibition of MAPK phosphorylation enhanced Hif-1α ubiquitination, and inhibited Hif-1α translocation into nucleus. Conclusively, Hif-1α and MAPK participate in HSC activation upon hypoxia.

Effect of Mirazid in Schistosoma japonicum-infected mice: parasitological and pathological assessment

Conflicting reports are found in the literature about the antischistosomal efficacy of Mirazid (MZ), which is a special formulation of myrrh obtained from the stem of the plant Commiphora molmol. This initiated the present study to assess this drug for the first time in experimental schistosomiasis japonicum. Mice were divided into four groups: infected untreated control (I); infected treated with MZ, 500mg/kg (II); infected treated with MZ, 250mg/kg (III); and infected treated with praziquantel (PZQ), 200mg/kg (IV). The drugs were given 7weeks post-infection for five successive days. All animals were killed 3weeks posttreatment. Results showed no signs of antibilharzial activity of MZ. Total worms, total tissue egg load, egg developmental stages, and granuloma area were not affected by any of the MZ treatment regimens as compared to the infected untreated group (P > 0.05 for all variables). These results were in contrast to those obtained in PZQ-treated animals in which 82.82% total worm reduction, 94.62% egg reduction, and 86.35% granuloma area reduction were observed. Also, it significantly increased the percentage of dead ova and decreased the percentage of mature ova with complete absence of immature ones in comparison with the control group (P < 0.01 for all variables). In conclusion, the results of the current study raise serious doubts about the antischistosomal activity of MZ.

The effects of interleukin (IL)-12 and IL-4 deficiency on worm development and granuloma formation in Schistosoma japonicum-infected mice

CD4(+) T-helper (Th) cell is widely recognized to be capable of influencing worm development and egg granuloma formation after schistosome infection. Interleukin (IL)-12 and IL-4 play key roles in regulation of Th cell differentiation. In the present study, we subcutaneously inoculated mice with hybridoma cells secreting monoclonal antibodies to neutralize IL-12 and IL-4 and explored the effects of IL-12 and IL-4 deficiency on the worm development and granuloma formation in mice infected with cercariae of Schistosoma japonicum. It was found that deficiency of host IL-12 and IL-4 supported normal parasite survival and fecundity. However, worm development (length and female fecundity) was significantly enhanced in anti-IL-12-treated mice. Mean length of worms in anti-IL-12-treated group was significantly greater than that of intact controls on day28 after infection (females, 11.84 ± 1.20mm vs. 9.45 ± 1.34; males, 9.35 ± 1.21mm vs. 8.10 ± 0.85mm, p < 0.05). Liver egg load per pair of worms (1,770.12 ± 470.67 vs. 806.08 ± 232.37, p < 0.05) and uterine egg load of ovigerous females (93.08 ± 27.85 vs. 46.05 ± 34.24, p < 0.05) in anti-IL-12-treated mice were significantly higher than those in intact control 28days postinfection. But these effects diminished 42days postinfection (p > 0.05). Granuloma size in anti-IL-12-treated mice was significantly larger than that in intact mice 42days postinfection (398.3 ± 80.7μm vs. 294.4 ± 72.2μm, p < 0.05). Granuloma fibrosis dramatically intensified in anti-IL-12-treated mice but diminished in anti-IL-4-treated mice. The results suggest that IL-12 may play an impeditive role in the development of S. japonicum and in granuloma formation as well as fibrosis. IL-4 may promote granuloma formation but have no effect on worm development.

Effects of γ-interferon on hepatic fibrosis of schistosoma japonicum-infected mice

To probe the effect of γ-IFN on hepatic fibrosis in schistosomiasis japonica. The amount and distribution of γ-IFN and extracellular matrix in the liver of 60 S. japonicum infected mice and 30 healthy mice at different stages, and their dynamics in 20 infected mice after administration of recombinant γ-interferon were determined by immunohistochemical streptavidin biotin peroxidase complex method. The amount of γ-IFN in liver peaked at the 16(th) week after infection (3 mice respectively reached 2+, 3+ and 4+ grade), which was higher than the levels of infected mice at the 8(th)-12(th) week (P < 0.01), and γ-IFN was mostly distributed around egg granuloma. Fibronectin, laminin, type I and III collagens in liver of most infected mice reached 1+ grade and individual 2+ grade at the 8(th) week after infection, which were higher than those of healthy controls (P < 0.01), and were linearly distributed around egg granuloma . With chronicity and decrease of γ-interferon, however, the matrix proteins and collagens gradually increased, peaked respectively at the 20(th) and 24(th) week (over 70% infected mice with 3+ to 4+ grade), became wide and thick, and deposited in band like or retiform shape around and in egg granuloma. After administration of γ-IFN, only 3 infected mice had 2+ grade of fibronectin at the 20(th) week, and 2 mice had 3+ grade of type III collagen at the 24(th) week, and none of them reached 4+ grade, which were significantly less than the untreated group at the same stage (P < 0.01-0.05). γ-interferon may play an important role in opposing the inflammatory response of egg granuloma, decreasing secretion and deposition of extracellular matrix in the liver and suppressing hepatic fibrosis.