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Background Macrophages play crucial roles in immune responses during the course of schistosomal infections. Methods We currently investigated influence of immunocompetent changes in macrophages via microarray-based analysis, mRNA expression analysis, detection of serum cytokines, and subsequent evaluation of the immune phenotypes following the differentiation of infection-induced lymphocytes in a unique T1/T2 double-transgenic mouse model. Results The gradual upregulation of genes encoding YM1, YM2, and interleukin (IL)-4/IL-13 receptors in infected mice indicated the role of type 2 alternatively activated macrophages (M2, AAMφs) in immune responses after Schistosoma japonicum egg production. FACS analysis showed that surface markers MHC class II (IA/IE) and CD8α+ of the macrophages also exhibited a dramatic change at the various time points before and after egg-production. The transgenic mouse experiments further demonstrated that the shifting of macrophage phenotypes influenced the percentage of helper T (Th)-2 cells, which was observed to be higher than that of Th1 cells, which increased only at 3 and 5 weeks post-infection. The differentiation of effector B cells showed a similar but more significant trend toward type-2 immunity. Conclusion These results suggest that the infection of mice with S. japonicum resulted in a final Th2- and Be2-skewed immune response. This may be due to phenotypic changes in the macrophages. The influence of alternatively activated macrophages was also activated by S. japonicum egg production. This study elucidated the existence of variations in immune mechanisms at the schistosome infection stages.

Background Hepatic stellate cell (HSC) activation plays a pivotal role in hepatic inflammation and liver fibrosis. TLR4 pathway activation has been reported to be involved in mice liver fibrosis induced by hepatitis virus infection, alcohol abuse, biliary ligation, carbon tetrachloride 4 treatment, and Schistosoma japonicum (Sj) infection. The effect and mechanisms of the cyclooxygenase 2 (COX2)/prostanoid E2 (PGE2) axis on liver fibrosis induced by Sj are still unclear. Methods Mice liver fibrosis were induced by cutaneous infection of Sj cercariae. COX-2 inhibitor, NS398 were injected from week 5 to week 7, while TLR4 inhibitor TAK242 were injected from week 4 to week 8 post Sj infection. Human HSCs line, LX-2 cells were cultured and exposed to LPS or synthetic PGE2, or pretreated by TAK242, TLR4-siRNA or NS398. Liver tissue and serum or in vitro cultured cell lysaste were collected at indicated time courses for exploring the relationship between TLR4 and COX2-PGE2 axis through qPCR, western blot, immunohistochemical assay, ect. One-way analysis of variance among multiple groups followed by Uncorrected Fisher’s LSD-t test or paired comparisons through t test were performed to tell the statistical differences. Results This study investigated the link between the COX2/PGE2 axis and TLR4 signaling in the induction of liver fibrogenesis in mice during Sj infection and in vitro culture of HSC strain-LX-2. The COX2/PGE2 axis was positively associated with Sj-induced liver fibrosis. TLR4 pathway activation stimulated the COX2/PGE2 axis in Sj-infected mice and in lipopolysaccharide (LPS)-exposed cultured HSCs. Synthetic PGE2 activated cultured HSCs through upregulation of alpha smooth muscle actin (α-SMA) expression. In LPS-triggered HSCs, NS398, a COX2 inhibitor, led to suppression of PGE2 synthesis and reduced expression of α-SMA and type I collagen (COL I). Conclusions These results indicate firstly the positive association of the COX2/PGE2 axis with liver fibrosis induced by Sj infection. TLR4 signaling may at least partially control the COX2/PGE2 axis in Sj-infected mice liver and in vitro cultured HSCs. The COX2/PGE2-EP2/EP4 axis might be a good drug target against liver fibrosis induced by Sj infection. Graphical Abstract

Background Several studies have assessed the role of gut microbiota in various cirrhosis etiologies, however, none has done so in the context of Schistosoma japonicum infection in humans. We, therefore, sought to determine whether gut microbiota is associated with S. japonicum infection-induced liver cirrhosis. Methods From December 2017 to November 2019, 24 patients with S. japonicum infection-induced liver cirrhosis, as well as 25 age- and sex-matched controls from the Zhejiang Province, China, were enrolled. Fecal samples were collected and used for 16S rRNA gene sequencing (particularly, the hypervariable V4 region) using the Illumina MiSeq system. Wilcoxon Rank-Sum and PERMANOVA tests were used for analysis. Results Eight hundred and seven operational taxonomic units (OTUs) were detected, of which, 491 were common between the two groups, whereas 123 and 193 were unique to the control and cirrhosis groups, respectively. Observed species, Chao, ACE, Shannon, Simpson, and Good’s coverage indexes, used for alpha diversity analysis, showed values of 173.4 ± 63.8, 197.7 ± 73.0, 196.3 ± 68.9, 2.96 ± 0.57, 0.13 ± 0.09, and 1.00 ± 0.00, respectively, in the control group and 154.0 ± 68.1, 178.6 ± 75.1, 179.9 ± 72.4, 2.68 ± 0.76, 0.19 ± 0.18, and 1.00 ± 0.00, respectively, in the cirrhosis group, with no significant differences observed between the groups. Beta diversity was evaluated by weighted UniFrac distances, with values of 0.40 ± 0.13 and 0.40 ± 0.11 in the control and cirrhosis groups, respectively (P > 0.05). PCA data also confirmed this similarity (P > 0.05). Meanwhile, the relative abundance of species belonging to the Bacilli class was higher in cirrhosis patients [median: 2.74%, interquartile range (IQR): 0.18–7.81%] than healthy individuals (median: 0.15%, IQR: 0.47–0.73%; P P Conclusions Cumulatively, our results suggest that the gut microbiota of S. japonicum infection-induced liver cirrhosis patients is similar to that of healthy individuals, indicating that bacterial taxa cannot be used as non-invasive biomarkers for S. japonicum infection-induced liver cirrhosis.

Background and Aim: Schistosomiasis (SCH) japonica is a zoonotic disease that can infect several mammalian hosts. Bovines, particularly water buffaloes, are considered the most important reservoir hosts due to the high levels of schistosome eggs, they excrete into the environment. In the Philippines, the previous studies have revealed a high prevalence of SCH in bovines in selected provinces in Luzon, Visayas, and Mindanao. However, there is a lack of studies on SCH in the Davao Region, Mindanao, where the infection remains a public health concern. This study aimed to determine the prevalence of SCH in water buffaloes in four barangays (villages) each in Braulio Dujali, Davao del Norte and Maragusan, Davao de Oro, Southeastern Mindanao, the Philippines. Materials and Methods: Fecal samples from 91 water buffaloes were collected intrarectally, processed using the formalin-ethyl acetate sedimentation technique, and examined microscopically to determine the prevalence of SCH. Results: A total of three water buffaloes (8.6%) in Maragusan were determined to be positive for Schistosoma japonicum, while none in Braulio Dujali. The prevalence of other parasites (Fasciola spp. [53.8%], Paramphistome spp. [20.9%], Amphistome spp. [16.5%], Strongyle spp. [11.0%], Balantidium spp. [9.9%], Eurytrema spp. [2.2%], and Gongylonema pulchrum [1.1%]) was also observed. Conclusion: The results of the study provide baseline data on the presence of S. japonicum in water buffaloes in the Davao Region, Mindanao. Strategies for controlling and eliminating SCH in animal reservoir hosts, especially in water buffaloes, are necessary for the long-term control and elimination of SCH in humans.

A vaccine is an important method to control schistosomiasis. Molecules related to lung-stage schistosomulum are considered potential vaccine candidates. We previously showed that glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and cathepsin L3 (CL3) displayed differential expression in the lung-stage schistosomula of Schistosoma japonicum cocultured with host cells. In the present study, we prepared the two proteins and detected the protective effects of SjGAPDH by immunizing mice with this protein alone and in combination with SjCL3 with or without Freund's adjuvant. Then, we investigated the possible mechanisms underlying S. japonicum infection. The results showed that vaccination of adjuvanted SjGAPDH decreased the worm burden (37.8%) and egg load (38.1%), and the combination of adjuvanted SjGAPDH and SjCL3 further decreased the worm burden (65.6%) and egg load (70.9%) during Schistosoma japonicum infection. However, the immunization of a combination of adjuvant-free SjGAPDH and SjCL3 displayed a lower protective effect (15%) than those of the adjuvanted SjCL3, the adjuvanted SjGAPDH, and a combination of adjuvanted SjGAPDH and SjCL3. Flow cytometric results showed that the frequency of regulatory T cells (Tregs) was lower (P0.05) in the group with adjuvanted SjGAPDH and SjCL3 (2.61%) than the remaining groups. The enzyme-linked immunosorbent assay (ELISA) results indicated that except for the uninfected and infected control groups, the remaining groups displayed a Th1-type shift in immune responses. These results showed the immunization of SjGAPDH resulted in partial protection (approximately 38%); inoculation with a combination of SjCL3 and SjGAPDH in Freund's adjuvant resulted in a high immunoprotective effect (65%) against Schistosoma japonicum infection in mice, which was possibly caused by the reduced percentage of Tregs and a Th1-type shift in immune responses; and SjCL3 has no adjuvant-like effect, dissimilar to SmCL3.

Background Hepatic fibrosis caused by chronic infection with Schistosoma japonica remains a serious public health problem in the world. Symptoms include inflammation, liver granuloma and fibrosis, whilst treatment options are still limited. This study aims to investigate whether and how traditional Chinese medicine Xiaochaihu decoction (XCH) could mitigate liver fibrosis caused by S. japonicum infection. Methods BALB/c mice were infected with S. japonicum cercariae and treated with XCH for 16 weeks. Liver pathological changes were assessed by H&E and Masson staining. NIH3T3 and Raw264.7 cells were treated with S. japonicum egg antigens with or without XCH treatment. Quantitative real-time PCR, western blot, immunfluorescence and ELISA were performed to determine the changes of levels of fibrogenic markers. Results XCH protected mouse liver from injuries and fibrosis caused by S. japonicum infection and considerably reduced egg burden in a dose-dependent manner. Infection with S. japonicum caused elevation of serum ALT, AST, ALP, HA and PIIINP levels and reduction of ALB and GLOB levels, which was markedly suppressed by XCH. The upregulation of TGF-β1, Hsp47, α-SMA, Col1A1 and Col3A1 in S. japonicum-infected mouse liver was also significantly inhibited by XCH. Schistosoma japonicum egg antigens promoted the expression of Hsp47, TGF-β1, Timp-1, α-SMA, Col1A1 and Col3A1 in NIH3T3 cells, and TGF-β1, CTGF, IL-13, IL-17 and IL-6 in Raw264.7 cells, which was inhibited by XCH, LY2157299 and shRNA-Hsp47. Conclusions These results demonstrated that the hepatic protective effects of Xiaochaihu decoction were mediated by HSP47/TGF-β axis.

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.

Background Schistosomiasis japonica is a serious zoonotic parasitic disease. Preliminary studies have shown that the expression of microRNA-181a (miR-181a) in the liver, lung and spleen tissues of susceptible host BALB/c mice and resistant host reed vole (Microtus fortis) 10 days post-infection (dpi) with Schistosoma japonicum was significantly different from pre-infection levels. This difference suggests the possibility that miR-181a expression may be related to the regulation of the hosts’ early immune response against S. japonicum infection and thereby affect the development and survival of parasites in their final hosts. Methods BALB/c mice, M. fortis, Toll-like receptor 4 (TLR4)-deficient mice and wild-type mice (C57BL/6) were infected with S. japonicum, and differences in miR-181a expression between BALB/c mice and M. fortis over different time points post-infection (0, 3, 7, 10 and 14 dpi) were compared. MiR-181a mimic, miR-181a inhibitor and irrelevant miRNA, as well as lipopolysaccharide (LPS), a TLR4 receptor ligand, were used to transfect mouse RAW264.7 macrophages. The expression levels of the TLR4 pathway-related cytokines interleukin (IL)-1β, tumor necrosis factor α (TNF-α) and IL-6 were detected by quantitative PCR analysis. Results The expression of miR-181a was significantly upregulated in the serum and liver of mice infected with S. japonicum and downregulated in the serum and liver of M. fortis. T-helper cell (Th1)-type cytokines, such as TNF-α, IL-6 and IL-1β, and Th2-type cytokines, such as IL-10 and IL-4, were differentially expressed in M. fortis and BALB/c mice in the early stage of infection. The expression level of miR-181a in the serum was threefold higher in TLR4-deficient mice than in wild-type mice 10 dpi with S. japonicum. The expression of IL-1β, TNF-α and IL-6 decreased in RAW264.7 cells transfected with miR-181a mimic and increased in cells transfected with miR-181a inhibitor. miR-181a expression was downregulated and the expressions of TLR4 and three TLR4 pathway-related cytokines (IL-1β, IL-6, and TNF-α) were upregulated in RAW264.7 macrophages stimulated with the TLR4 receptor ligand LPS. Conclusion These results suggest the possibility of mutual regulation between miR-181a and the TLR4 signaling pathway during S. japonicum infection. miR-181a may regulate the expression of pro-inflammatory factors through the TLR4 receptor pathway and participate in the immunomodulatory effect of anti-S. japonicum infection. Graphical abstract

S. japonicum infection can induce granulomatous inflammation in the liver of the host. Granulomatous inflammation limits the spread of infection and plays a role in host protection. Toll-like receptor 7 (TLR7) is an endosomal TLR that recognizes single-stranded RNA (ssRNA). In this study, the role of TLR7 in S. japonicum infection-induced hepatitis was investigated in both normal and TLR7 knockout (KO) C57BL/6 mice. The results indicated that TLR7 KO could aggravate S. japonicum infection-induced damage in the body, with less granuloma formation in the tissue, lower WBCs in blood, and decreased ALT and AST in the serum. Then, the expression of TLR7 was detected in isolated hepatic lymphocytes. The results indicated that the percentage of TLR7+ cells was increased in the infected mice. Hepatic macrophages, DCs, and B cells could express TLR7, and most of the TLR7-expressing cells in the liver of infected mice were macrophages. The percentage of TLR7-expressing macrophages was also increased after infection. Moreover, macrophages, T cells, and B cells showed significant changes in the counts, activation-associated molecule expression, and cytokine secretion between S. japonicum-infected WT and TLR7 KO mice. Altogether, this study indicated that TLR7 could delay the progression of S. japonicum infection-induced hepatitis mainly through macrophages. DCs, B cells, and T cells were involved in the TLR7-mediated immune response.

BackgroundCD4+T helper (Th) cells play critical roles in both host humoral and cellular immunity against parasitic infection and in the immunopathology of schistosomiasis. T follicular helper (Tfh) cells are a specialized subset of Th cells involved in immunity against infectious diseases. However, the role of Tfh cells in schistosome infection is not fully understood. In this study, the dynamics and roles of Tfh cell regulation were examined. We demonstrated that granulocytic myeloid-derived suppressor cells (G-MDSC) can suppress the proliferation of Tfh cells.MethodsThe levels of Tfh cells and two other Th cells (Th1, Th2) were quantitated at differentSchistosoma japonicuminfection times (0,3, 5, 8, 13 weeks) using flow cytometry. The proliferation of Tfh cells stimulated by soluble egg antigen (SEA) and soluble worm antigen (SWA) in vivo and in vitro were analyzed. Tfh cells were co-cultured with MDSC to detect the proliferation of Tfh cells labelled by 5(6)-carboxyfluorescein diacetateN-succinimidyl ester. We dynamically monitored the expression of programmed cell death protein 1 (PD-1) on the surface of Tfh cells and programmed cell death ligand 1 (PD-L1) on the surface of MDSC at different infection times (0, 3, 5, 8 weeks). Naïve CD4+T cells (in Tfh cell differentiation) were co-cultured with G-MDSC or monocytic MDSC in the presence, or in the absence, of PD-L1 blocking antibody.ResultsThe proportion of Tfh cells among CD4+T cells increased gradually with time ofS. japonicuminfection, reaching a peak at 8 weeks, after which it decreased gradually. Both SEA and SWA caused an increase in Tfh cells in vitro and in vivo. It was found that MDSC can suppress the proliferation of Tfh cells. The expression of PD-1 on Tfh cells and PD-L1 from MDSC cells increased with prolongation of the infection cycle. G-MDSC might regulate Tfh cells through the PD-1/PD-L1 pathway.ConclusionsThe reported study not only reveals the dynamics of Tfh cell regulation duringS. japonicuminfection,but also provides evidence that G-MDSC may regulate Tfh cells by PD-1/PD-L1. This study provides strong evidence for the important role of Tfh cells in the immune response toS. japonicuminfection.Graphical abstract

Schistosomiasis affects at least 200 million people in tropical and subtropical areas. The major pathology of schistosomiasis is egg‐induced liver granuloma characterized by an eosinophil‐rich inflammatory infiltration around the eggs, which subsequently leads to hepatic fibrosis and circulatory impairment in host. However, the mechanisms how eosinophils are recruited into the liver, which are crucial for the better understanding of the mechanisms underlying granuloma formation and control of schistosomiasis, remain unclear. In this study, we showed that follicular helper T (Tfh) cells participate in recruitment of eosinophils into liver partially by producing CXCL12 during schistosome infection. Our findings uncovered a previously unappreciated role of Tfh cells in promotion of the development of liver granuloma in schistosomiasis, making Tfh‐CXCL12‐eosinophil axis a potential target for intervention of schistosomiasis.

Background and Aim: Schistosomiasis is one of the seven neglected tropical diseases that are of public health concern in the Philippines. The disease is prevalent in few of the barangays (communities) in Koronadal City, Philippines. Status of the Schistosoma japonicum infections in domestic animal reservoir host has yet to be explored in these endemic communities. The study aimed to determine the prevalence and infection intensity of the disease in cattle and water buffaloes of endemic communities of Koronadal City. Materials and Methods: Schistosomiasis was investigated in 70 cattle and 38 water buffaloes from three endemic communities in Koronadal City. The copro-parasitological technique used was the formalin-ethyl acetate sedimentation method. Results: S. japonicum infection was observed in 48.6% of cattle and 60.5% in water buffaloes. The bovine contamination index indicated that all infected animals released 3,505,500 eggs/day. On average, infected cattle released 1,674,500 eggs daily, while infected water buffaloes liberated 1,932,000 eggs in the environment daily. Conclusion: Cattle and water buffaloes in these endemic areas are infected with S. japonicum. These animals release large numbers of eggs in the environment daily; hence, played an important role in disease transmission. Those living and working in endemic areas should be aware of the inherent dangers of the disease.

Extracellular vesicles are critical regulators of host-parasite interactions. We previously demonstrated that Schistosoma japonicum EVs contain a remarkably high abundance of host miR-148a. Here, we characterised the abundance of miR-148a in circulation, in peripheral immune cells, and in plasma EVs of S. japonicum-infected mice. The results suggested the high abundance of miR-148a in macrophages to be likely linked to S. japonicum EVs. Additionally, miR-148a was found to target PTEN through the PI3K/AKT pathway to regulate cytokine production in macrophages. Consequently, our findings suggest that high abundance of miR-148a in macrophages may be associated with S. japonicum EVs, and regulate the host immune response during schistosome infection.

Background and Aim: Schistosomiasis is endemic in Indonesia and is found in three remote areas in Central Sulawesi Province. Non-human mammals serve as reservoir hosts, meaning the disease is zoonotic. The previous schistosomiasis studies in animals from the Lindu Subdistrict did not determine which domestic animal species can serve as the primary source of transmission. No animals have been treated in Indonesia to control the disease; therefore, the parasite's life cycle is not blocked entirely. This study aimed to determine the prevalence and identify the risk factors associated with, Schistosoma japonicum infection in animals, and identify animals' relative contributions to S. japonicum transmission in the Lindu Subdistrict. Materials and Methods: A cross-sectional survey of S. japonicum infected animals was conducted in five villages of the Lindu Subdistrict. Fecal samples were collected from 134 selected animals (13 cattle, 26 buffaloes, 28 horses, 59 pigs, and 8 dogs). S. japonicum infection and infection intensity were determined using the Danish Bilharziasis Laboratory method. Environmental contamination with schistosome eggs was measured. The data were analyzed using a Chi-square test. Results: The overall prevalence of schistosomiasis was 32.9%, with the prevalence of infection in each species of animal at 61.5% in cattle, 42.3% in buffaloes, 25.0% in horses, 35.6% in pigs, and 12.5% in dogs. Free-range pigs were 8.667 times more likely to have S. japonicum infection than pigs kept in cages. Buffaloes, cattle, and horses were the primary sources of S. japonicum egg contamination, with relative transmission indices of 59.15%, 22.80%, and 10.61%, respectively. Conclusion: Bovines and horses are the main contributors to schistosomiasis transmission in the Lindu Subdistrict. In conjunction with other schistosomiasis control programs, the government should treat infected animals living within endemic areas where there are high infection rates of S. japonicum.

Schistosomiasis japonica caused by Schistosoma japonicum infection is recognized as a considerable economic and public health concern in Asia. Oncomelania hupensis is the sole intermediate host of S. japonicum. The only molluscicide recommended by World Health Organization (WHO) since 1960s is relative toxic to other aquatic species. In this article, we evaluated the novel molluscicide PPU07 in field trials on their efficiency against O. hupensis and toxicity for local fish. 25% PPU07 sulfate WP exhibited similar molluscicidal effect at 2.0 g/m2 and 2.0 g/m3 in the spraying and immersion trials with the WHO recommended molluscicide niclosamide (1 g/m2 and 1 g/m3). The mortality rates reached 95% and 96%, respectively. Moreover, little toxicity was observed for local fish and other aquatic organisms at the effective molluscicidal concentrations. In all, 25% PPU07 sulfate WP is a promising molluscicide for snail control, particularly in semi-commercial or commercial aquaculture ponds.

Despite the paramount role of TLRs in the induction of innate immune and inflammatory responses, there is a paucity of studies on the role of TLRs in Schistosoma japonicum infection. Here, we observed obvious infiltration of inflammatory cells in S. japonicum-infected C57BL/6 mouse lungs. Expression and release of IFN-γ, IL-4, and IL-17 were significantly higher in pulmonary lymphocytes from infected mice compared with control mice in response to anti-CD3 plus anti-CD28 mAbs. Higher percentages of TLR2, TLR3, TLR4, and TLR7 were expressed on such lymphocytes, and the TLR agonists PGN, Poly I:C, LPS, and R848 induced a higher level of IFN-γ. However, a higher level of IL-4 was found in the supernatant of pulmonary lymphocytes from infected mice stimulated by these TLR agonists plus CD3 Ab. Only R848 plus anti-CD3 mAb could induce a higher level of IFN-γ in such lymphocytes. TLR expressions were then compared on different pulmonary lymphocytes after infection, including T cells, B cells, NK cells, NKT cells, and γδT cells. The expression levels of TLR3 on T cells, B cells, NK cells, and γδT cells were increased in the lungs after infection. NK cells also expressed higher levels of TLR4 after infection of control mice. Collectively, these findings highlight the potential role of TLR expression in the context of S. japonicum infection.

In China, bovines are believed to be the most common animal source of human schistosomiasis infections, though little is known about what factors promote bovine infections. The current body of literature features inconsistent, and sometimes contradictory results, and to date, few studies have looked beyond physical characteristics to identify the broader environmental conditions that predict bovine schistosomiasis. Because schistosomiasis is a sanitation-related, water-borne disease transmitted by many animals, we hypothesized that several environmental factors − such as the lack of improved sanitation systems, or participation in agricultural production that is water-intensive − could promote schistosomiasis infection in bovines. Using data collected as a part of a repeat cross-sectional study conducted in rural villages in Sichuan, China from 2007 to 2016, we used a Random Forests, machine learning approach to identify the best physical and environmental predictors of bovine S. japonicum infection. Candidate predictors included: 1) physical/biological characteristics of bovines, 2) human sources of environmental schistosomes, 3) socio-economic indicators, 4) animal reservoirs, and 5) agricultural practices. The density of bovines in a village and agricultural practices such as the area of rice and dry summer crops planted and the use of night soil as an agricultural fertilizer, were among the top predictors of bovine S. japonicum infection in all collection years. Additionally, human infection prevalence, pig ownership and bovine age were found to be strong predictors of bovine infection in at least one year. Our findings highlight that presumptively treating bovines in villages with high bovine density or human infection prevalence may help to interrupt transmission. Furthermore, village-level predictors were stronger predictors of bovine infection than household-level predictors, suggesting future investigations may need to apply a broad ecological lens to identify potential underlying sources of persistent transmission.

Schistosoma japonicum infection showed protective effects against allergic airway inflammation (AAI). However, controversial findings exist especially regarding the timing of the helminth infection and the underlying mechanisms. Most previous studies focused on understanding the preventive effect of S. japonicum infection on asthma (infection before allergen sensitization), whereas the protective effects of S. japonicum infection (allergen sensitization before infection) on asthma were rarely investigated. In this study, we investigated the protective effects of S. japonicum infection on AAI using a mouse model of OVA-induced asthma. To explore how the timing of S. japonicum infection influences its protective effect, the mice were percutaneously infected with cercaria of S. japonicum at either 1 day (infection at lung-stage during AAI) or 14 days before ovalbumin (OVA) challenge (infection at post–lung-stage during AAI). We found that lung-stage S. japonicum infection significantly ameliorated OVA-induced AAI, whereas post–lung-stage infection did not. Mechanistically, lung-stage S. japonicum infection significantly upregulated the frequency of regulatory T cells (Treg cells), especially OVA-specific Treg cells, in lung tissue, which negatively correlated with the level of OVA-specific immunoglobulin E (IgE). Depletion of Treg cells in vivo partially counteracted the protective effect of lung-stage S. japonicum infection on asthma. Furthermore, transcriptomic analysis of lung tissue showed that lung-stage S. japonicum infection during AAI shaped the microenvironment to favor Treg induction. In conclusion, our data showed that lung-stage S. japonicum infection could relieve OVA-induced asthma in a mouse model. The protective effect was mediated by the upregulated OVA-specific Treg cells, which suppressed IgE production. Our results may facilitate the discovery of a novel therapy for AAI.

In areas endemic to schistosomiasis, fetal exposure to schistosome antigens prime the offspring before potential natural infection. Praziquantel (PZQ) treatment for Schistosoma japonicum infection in pregnant women has been demonstrated to be safe and effective. Our objectives were to evaluate whether maternal PZQ treatment modifies the process of in utero sensitization to schistosome antigens potentially impacting later risk of infection, as well as immune response to S. japonicum. We enrolled 295 children at age six, born to mothers with S. japonicum infection who participated in a randomized control trial of PZQ versus placebo given at 12–16 weeks gestation in Leyte, The Philippines. At enrollment, we assessed and treated current S. japonicum infection and measured serum cytokines. During a follow-up visit four weeks later, we assessed peripheral blood mononuclear cell (PBMC) cytokine production in response to soluble worm antigen preparation (SWAP) or soluble egg antigen (SEA). Associations between maternal treatment group and the child’s S. japonicum infection status and immunologic responses were determined using multivariate linear regression analysis. PZQ treatment during pregnancy did not impact the prevalence (P = 0.12) or intensity (P = 0.59) of natural S. japonicum infection among children at age six. Among children with infection at enrollment (12.5%) there were no significant serum cytokine concentration differences between maternal treatment groups. Among children with infection at enrollment, IL-1 production by PBMCs stimulated with SEA was higher (P = 0.03) in the maternal PZQ group compared to placebo. Among children without infection, PBMCs stimulated with SEA produced greater IL-12 (P = 0.03) and with SWAP produced less IL-4 (P = 0.01) in the maternal PZQ group compared to placebo. Several cytokines produced by PBMCs in response to SWAP and SEA were significantly higher in children with S. japonicum infection irrespective of maternal treatment: IL-4, IL-5, IL-10, and IL-13. We report that maternal PZQ treatment for S. japonicum shifted the PBMC immune response to a more inflammatory signature but had no impact on their offspring’s likelihood of infection or serum cytokines at age six, further supporting the safe use of PZQ in pregnant women. Trial Registration: ClinicalTrials.gov NCT00486863., Author summary Children living in areas endemic to schistosomiasis typically do not present signs of acute illness during infection. It is believed that fetal exposure from a pregnant mother with infection primes the offspring and influences the child’s susceptibility and immune response to infection. Praziquantel treatment for Schistosoma japonicum infection in pregnant women has been demonstrated to be safe and effective, but the long-term impact on the child’s immunity is not fully understood. This study enrolled 295 children at age six, who were born to mothers who participated in a randomized controlled trial of praziquantel vs placebo for S. japonicum infection during pregnancy. The children were assessed and treated for S. japonicum infection and blood was collected to measure immune response markers. We found that praziquantel treatment during pregnancy did not impact the prevalence or intensity of naturally acquired S. japonicum infection among children at age six. Among the 37 children with S. japonicum infection, immune response markers did not differ by maternal treatment group. This evidence further supports the safe use of praziquantel for pregnant women.

The deposition of Schistosoma japonicum (S. japonicum) eggs commonly induces inflammation, fibrosis, hyperplasia, ulceration, and polyposis in the colon, which poses a serious threat to human health. However, the underlying mechanism is largely neglected. Recently, the disorder of glucose and lipid metabolism was reported to participate in the liver fibrosis induced by the parasite, which provides a novel clue for studying the underlying mechanism of the intestinal pathology of the disease. This study focused on the metabolic reprogramming profiles of glucose and lipid in the colon of mice infected by S. japonicum. We found that S. japonicum infection shortened the colonic length, impaired intestinal integrity, induced egg-granuloma formation, and increased colonic inflammation. The expression of key enzymes involved in the pathways regulating glucose and lipid metabolism was upregulated in the colon of infected mice. Conversely, phosphatase and tensin homolog deleted on chromosome ten (PTEN) and its downstream signaling targets were significantly inhibited after infection. In line with these results, in vitro stimulation with soluble egg antigens (SEA) downregulated the expression of PTEN in CT-26 cells and induced metabolic alterations similar to that observed under in vivo results. Moreover, PTEN over-expression prevented the reprogramming of glucose and lipid metabolism induced by SEA in CT-26 cells. Overall, the present study showed that S. japonicum infection induces the reprogramming of glucose and lipid metabolism in the colon of mice, and PTEN may play a vital role in mediating this metabolic reprogramming. These findings provide a novel insight into the pathogenicity of S. japonicum in hosts.

Inflammatory bowel disease (IBD)-related inflammation is closely associated with the initiation and progression of colorectal cancer. IBD is generally treated with 5-aminosalicylic acid and immune-modulating medication, but side effects and limitations of these therapies are emerging. Thus, the development of novel preventative or therapeutic approaches is imperative. Here, we constructed a dextran sodium sulphate (DSS)-induced IBD mouse model that was infected with monosexual Schistosoma japonicum cercariae (mSjci) at day 1 or administered dexamethasone (DXM) from days 3 to 5 as a positive control. The protective effect of mSjci on IBD mice was evaluated through their assessments of their clinical signs, histopathological lesions and intestinal permeability. To uncover the underlying mechanism, the Th1/Th2 balance and Treg cell population were also examined. Additionally, the alterations in the gut microbiota were assessed to investigate the interaction between the mSjci-modulated immune response and pathogenic microbiome. Mice treated with DSS and mSjci showed fewer IBD clinical signs and less impaired intestinal permeability than DSS-treated mice. Mechanistically, mSjci modulated the Th1/Th2 balance by repressing IFN-γ production, promoting IL-10 expression and enhancing the Treg subset population. Moreover, mSjci notably reshaped the structure, diversity and richness of the gut microbiota community and subsequently exerted immune-modulating effects. Our findings provide evidence showing that mSjci might serve as a novel and effective protective strategy and that the gut microbiota might be a new therapeutic target in IBD.

The E3 deubiquitinating enzyme ubiquitin-specific proteolytic enzyme 21 (USP21) plays vital roles in physiological activities and is required for Treg-cell-mediated immune tolerance. Using a murine model infected with Schistosoma japonicum, we observed that there were more cercariae developed into adults and more eggs deposited in the livers of the USP21fl/flFOXP3Cre (KO) mice. However, immunohistochemistry showed that the degree of egg granuloma formation and liver fibrosis was reduced. In USP21fl/flFOXP3Cre mice, levels of IFN-gamma, IL-4, anti-soluble egg antigen (SEA) IgG and anti-soluble worm antigen preparation (SWAP) IgG increased in blood, as determined using ELISAs and multiplex fluorescent microsphere immunoassays, while the levels of IL-10, lL-17A, IL-23, IL-9, and anti-SEA IgM decreased. In addition, the levels of the USP21 protein and mRNA in the liver and spleen of KO mice decreased. We further observed increased Th1 responses amplified by Tregs (regulatory T cells) and compromised Th17 responses, which alleviated the liver immunopathology. We speculated that these changes were related to polarization of Th1-like Tregs. Our results revealed the roles of USP21 in Treg-cell-mediated regulation of immune interactions between Schistosoma and its host. USP21 may have potential for regulating hepatic fibrosis in patients with schistosomiasis.

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.

In this study, we investigated the use of recombinant antigens thioredoxin peroxidase-1 (rSjTPx-1) and tandem repeat rSj1TR in evaluating the antibody positivity rates of Schistosoma japonicum infection among water buffaloes from four endemic areas in the Philippines, two municipalities with high endemicity (Calatrava, Negros Occidental and Catarman, Northern Samar) and two municipalities nearing elimination with no cases of human schistosomiasis (Talibon and Trinidad, Bohol). These recombinant antigen ELISA assays were compared with other diagnostic tests including SEA-ELISA, FECT, and fecal-based PCR. Results showed that rSj1TR-ELISA has the highest agreement with PCR in all study areas. Furthermore, significant positivity rates among water buffaloes were seen in Talibon and Trinidad, indicating that water buffaloes are maintaining the schistosome parasites in transmission areas even in the absence of human infection. Hence, serological assay using a more sensitive and specific rSj1TR-ELISA can be used for animal surveillance to prevent emergence and re-emergence of human schistosomiasis.

Background: One of the serious complications induced by Schistosoma japonicum infection is the development of liver cirrhosis. Several studies have assessed the role of gut microbiota in cirrhosis of different etiologies, but none has done so in the context of S. japonicum infection in humans. Here, to explore the possible role of gut microbiota in S. japonicum infection-induced liver cirrhosis, we conducted an observational clinical study.Methods: Twenty-four patients with S. japonicum infection-induced liver cirrhosis and 25 age- and gender-matched controls from Zhejiang Province, China, were enrolled in the study. Fecal samples were collected and used for 16S rRNA gene hypervariable V4 region Illumina MiSeq sequencing.Results: Eight hundred seven operational taxonomic units (OTUs) were detected, of which 491 were common in the two groups, while 123 and 193 were unique for the control and cirrhosis groups, respectively. Overall, no significant differences in both alpha and beta diversities and overall microbiota structure were found in the two groups. However, Bacilli (Class) and Lactobacillales (Order) were significantly higher in patients with S. japonicum infection-induced liver cirrhosis than in healthy individuals.Conclusions: Altogether, our results suggest that the gut microbiota of S. japonicum infection-induced liver cirrhosis patients is similar to that of healthy individuals.

Microtus fortis (M. fortis) so far is the only mammal host that exhibits intrinsic resistance against Schistosoma japonicum infection. However, the underlying molecular mechanisms of this intrinsic resistance are not yet known. Here we performed the first de novo genome assembly of M. fortis, comprehensive gene annotation and evolution analysis. Furthermore, we compared the recovery rate of schistosome, pathological change and liver transcriptome between non-permissive host M. fortis and susceptible host mouse at different time points after Schistosome infection. We reveal that Immune response of M. fortis and mouse is different in time and type. M. fortis activates immune and inflammatory responses on the 10th days post infection, involving in multiple pathways, such as leukocyte extravasation, antibody activation (especially IgG3), Fc-gamma receptor mediated phagocytosis, and interferon signaling cascade. The strong immune responses of M. fortis in early stages of infection play important roles in preventing the development of schistosome. On the contrary, intense immune response occurred in mouse in late stages of infection (28~42 days post infection), and cannot eliminate schistosome. Infected mouse suffers severe pathological injury and continuous decrease of important functions such as cell cycle and lipid metabolism. Our findings offer new insights to the intrinsic resistance mechanism of M. fortis against schistosome infection. The genome sequence also provides bases for future studies of other important traits in M. 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.

Human schistosomiasis, which is caused by schistosomes, is a zoonosis that is difficult to control because of the many reservoir hosts. However, Microtus fortis is the only mammal that is naturally resistant to Schistosoma japonicum infection known in China, in which S. japonicum growth and development were arrested on day 12, and the worms eliminated on day 20 post-infection. In this review, we present an overview of the established and purported mechanisms of resistance to S. japonicum infection in M. fortis in comparison to Rattus norvegicus, a semi-permissive host. Clarifying the mechanism of this efficient resistance can help us to better understand host-parasite interaction and to provide better methods to control schistosomiasis.

Humans and dogs live very close together and share various pathogens causing zoonotic parasitoses like schistosomiasis. A previous population genetics study done for schistosomes in the Philippines suggested that there is a high transmission level of Schistosoma japonicum among humans and dogs proving that the latter are important reservoirs for this zoonotic parasite. A more sensitive and specific test detecting schistosome infection in dogs will therefore strengthen the zoonotic surveillance, which might help in the possible elimination of this ancient disease. In this study, recombinant thioredoxin peroxidase-1 (SjTPx-1) and tandem repeat proteins (Sj1TR, Sj2TR, Sj4TR, Sj7TR) previously tested on human and water buffalo samples were used to assess its diagnostic applicability to dogs. Fifty-nine dog serum and stool samples were collected in the schistosomiasis-endemic municipalities of Calatrava, Negros Occidental and Catarman, Northern Samar in the Philippines and examined using the ELISA as compared to microscopy and fecal sample-based PCR. Samples positive for Babesia gibsoni and Dirofilaria immitis were also used to check for cross-reaction. Results showed that SjTPx-1 (80% sensitivity, 92.3% specificity) and Sj7TR (73.3% sensitivity, 92.3% specificity) have good potentials for diagnosing S. japonicum infection in dogs. These diagnostic antigens will therefore improve the surveillance in the transmission of the parasites from dogs to humans.

USP21, an E3 de-ubiquitin enzyme playing vital roles in physiological activities, is important for Treg cells to maintain immune homeostasis and control immune tolerance. To understand its diverse functions and potential mechanism is essential for disease development. We, using the USP21 gene-conditional knock-out mice model of Schistosoma Japonicum infection, found more cercariae developed into adults, and more eggs deposited in the liver in KO mice. However, immunohistochemistry showed the degree and the area of egg granuloma and liver fibrosis were both reduced. This suggested knock-out USP21 did affect the immunoregulation between schistosomes and the host. In KO mice the content of IFN-gamma and IL-4, and the expression of anti-SEA IgG and anti-SWAP IgG both increased in the liver, spleen and blood by flow cytometry, while the content of IL-10, lL-17A, IL-23, IL-9 and the expression of USP21 and anti-SEA IgM decreased. This indicated USP21-knockout-Tregs promoted both Th1-type and Th2-type immunity and inhibited other immunities during schistosomes infection, which disordered the host immunity. This study revealed the immunomodulatory of USP21 and preliminarily suggests it might be essential to regulate the complex immune network between the host and schistosomes. USP21 provides a new possible target for schistosomiasis treatment in the future.Author summarySchistosomiasis is a common neglected tropical disease that affects more than 230 million people worldwide. Therefore, the study on the mechanism of immune interaction between schistosomas and the host is not only helpful for the understanding of immune homeostasis, but also helpful for the further development of the treatment of schistosomiasis. Ubiquitin Specific Protease 21(USP21) has been shown to be involved in the regulation of many biological processes, such as maintaining immune homeostasis and regulating cell growth. Here, we observed that the specific deletion of USP21 led to the decrease of mice’s ability to resist schistosomes infection and promoted the survival of schistosomes. It was also proved that unstable regulatory T cells would produce polarization phenomenon and promote differentiation to helper T cells, which would lead to disorder of immune response in mice. However, this process reduced the serious immune pathological damage caused by egg granuloma. Our findings reveal that USP21 may be an important molecule regulating immune interaction between Schistosoma japonicum and the host.

Background The modifiable areal unit problem (MAUP) arises when the support size of a spatial variable affects the relationship between prevalence and environmental risk factors. Its effect on schistosomiasis modelling studies could lead to unreliable parameter estimates. The present research aims to quantify MAUP effects on environmental drivers of Schistosoma japonicum infection by (i) bringing all covariates to the same spatial support, (ii) estimating individual-level regression parameters at 30 m, 90 m, 250 m, 500 m and 1 km spatial supports, and (iii) quantifying the differences between parameter estimates using five models. Methods We modelled the prevalence of Schistosoma japonicum using sub-provinces health outcome data and pixel-level environmental data. We estimated and compared regression coefficients from convolution models using Bayesian statistics. Results Increasing the spatial support to 500 m gradually increased the parameter estimates and their associated uncertainties. Abrupt changes in the parameter estimates occur at 1 km spatial support, resulting in loss of significance of almost all the covariates. No significant differences were found between the predicted values and their uncertainties from the five models. We provide suggestions to define an appropriate spatial data structure for modelling that gives more reliable parameter estimates and a clear relationship between risk factors and the disease. Conclusions Inclusion of quantified MAUP effects was important in this study on schistosomiasis. This will support helminth control programmes by providing reliable parameter estimates at the same spatial support and suggesting the use of an adequate spatial data structure, to generate reliable maps that could guide efficient mass drug administration campaigns.

Although parasitic infection affects the glucose homeostasis of mice, only few studies have integrated epidemiological and animal data to determine the effect of Schistosoma japonicum infection on mice metabolism. The current study assessed the effects of S. japonicum infection on blood glucose and other metabolic parameters in both patients and animal models of chronic schistomiasis. A total of 2183 patients with chronic schistosomiasis and age- and gender-matched individuals without schistosomiasis (n = 1798) were enrolled in this study. Fasting blood glucose and other metabolic parameters, including body mass index (BMI) and serum triglyceride and total cholesterol, were compared between the two groups. Mice infected with S. japonicum were used to test the effects of the parasite on glucose tolerance. We found that chronic schistosomiasis patients had significantly lower BMI and fasting blood glucose, serum triglyceride, and total cholesterol levels than non-schistosomiasis individuals. In the animal studies, both bisexual and unisexual S. japonicum infection improved glucose tolerance in wild-type mice. Additionally, S. japonicum-infected ob/ob mice, a model that spontaneously develops obesity and diabetes, also had decreased body weight and improved glucose tolerance. We further observed that S. japonicum-infected mice had lower inflammatory gene expression in the visceral white adipose tissue than the control mice. Collectively, our results demonstrated that S. japonicum infection improved glucose tolerance and other metabolic parameters both in human and animals. Downregulated inflammatory gene expression due to S. japonicum infection might be among the mechanisms for the improved glucose tolerance.

With the growing incidence of closed schistosomiasis and uncommon presentations, there is a risk of the infection rate being underestimated. A study in Japan reported an unexplained case of endocarditis that was finally diagnosed as a complex Schistosoma japonicum infection; in the absence of advanced techniques, the diagnosis was delayed. We therefore set out to explore the incidence of Schistosoma mansoni in endocarditis patients coming from areas of Egypt where S. mansoni is endemic. We also investigated histopathological changes in the cardiac valves and the presence of cell-free parasite DNA (CFPD) in cardiac tissues of laboratory mice infected with S. mansoni. The study included 186 patients with the manifestations of infective endocarditis. Eggs were detected in the stool samples of 5.91% of patients. Seropositivity was reported in 23.66% of patients and antigen was detected in the urine samples of 10.21%. Using real-time polymerase chain reaction (PCR), CFPD was detected in the blood of 6.98% of the endocarditis patients and 95% of the infected mice, while the cardiac samples of 45% of the mice tested positive for CFPD (means ± SD = 1390.2 ± 283.65, 2158.72 ± 1103.1 and 5.71 ± 2.91, respectively). Histopathological examination revealed abnormal collagen deposition, inflammatory cells and haemorrhagic pigmentation in the heart sections. Despite the low incidence of S. mansoni infection in the studied cohort, the presence of CFPD in the cardiac tissue of infected mice makes it necessary to: (1) investigate the hazards of CFPD deposition in endothelium-rich organs; and (2) test the potential of CFPD to trigger tissue inflammation, abnormal proliferation or genome integration.

Schistosomiasis is one of the world's major public health problems in terms of morbidity and mortality, causing granulomatous inflammation and cumulative fibrosis. This study explored in vivo and vitro effects of miR-29b-3p in granulomatous liver fibrosis by targeting COL1A1 and COL3A1 in Schistosoma japonicum infection. Thirty male Balb/c mice were assigned to normal control and model (percutaneous infection of cercariae of S. japonicum) groups. NIH-3T3 mouse embryonic fibroblasts were designated into blank, NC, miR-29b-3p mimic, TGF-β1, TGF-β1 + NC, and TGF-β1 + miR-29b-3p mimic groups. HE and Masson staining were employed to observe the pathological changes and collagenous fibrosis. The expression of α-SMA, COL1A1, COL3A1, TIMP-1 was determined by immunohistochemistry. The RT-qPCR, Western blotting and immunofluorescence staining were conducted to determine expression of miR-29b-3p, COL1A1, and COL3A1. CCK-8 assay and flow cytometry were performed to evaluate viability and apoptosis. The relative expression of miR-29b-3p decreased in the model group. The model group showed marked fibrosis in liver tissues. The expression of α-SMA, COL1A1, COL3A1, TIMP-1 was higher in the model group than that in the normal control group. Dual luciferase reporter gene assay revealed that miR-29b-3p directly targeted COL1A1 and COL3A1. Compared with the blank, NC, TGF-β1 and TGF-β1 + NC groups, the miR-29b-3p mimic group exhibited up-regulated expression of miR-29b-3p and MMP-9 but down-regulated expression of TIMP-1, HSP47, α-SMA, COL1A1, and COL3A1; while lower cell viability but higher apoptosis rate showed. It indicated that miR-29b-3p prevents S. japonicum-induced liver fibrosis by inhibiting COL1A1 and COL3A1.

In spite of long-term integrated control programs for Schistosoma japonicum infection in China, the infection is still persistent due to its zoonotic transmission and disease severity which further complicate its control. Th1, Th2, and T-reg cells are involved in S. japonicum immunity; however, their exact roles in immunopathology of this infection are still questionable. Therefore, the monitoring of these T cell subsets' immune responses during a primary infection of S. japonicum at both transcriptional (mRNA) and protein (cytokines) levels would be essential to point out. In experimentally infected white New Zealand rabbits, mRNA expression levels of TBX2, IRF8, GATA3, STAT6, FoxP3, and MAFF were evaluated using qPCR, whereas Th1 (IFN-γ and TNF-α), Th2 (IL4 and IL13), and T-reg (IL10 and TGF-β1) cytokines were measured by ELISA test. Those parameters were estimated at two phases: the first being 4 and 8 weeks post-infection and the second phase at 12 weeks post-infection. The infected rabbits were categorized into group1 which was treated with praziquantel after the 8th week of infection and group 2 which was left untreated. In the first stage of infection, Th1 was superior to the other types at both mRNA (TBX2 and IRF8) and protein (IFN-γ and TNF-α) levels, but at the late stage, Th2 cytokines (IL4 and IL13) were surprisingly dominated without comparable change in Th2 transcriptional level in group 1. Concisely, the evaluation of T cell transcriptional factors provided clearer evidence about T cellular roles which would be a valuable supplement to control this disease in terms of protective and therapeutic vaccinations.

Myeloid-derived suppressor cells (MDSCs), a heterogeneous group of immune cells from the myeloid lineage, play an important part in suppression of host immune responses during many pathologic conditions, including cancer and infectious diseases. Thus, understanding the functional diversity of these cells as well as the underlying mechanisms is crucial for the development of disease control strategies. The role of MDSCs during Schistosoma japonicum infection, however, is not clear, and there is a lack of systematic study so far. In this study, we provide strong evidence that the soluble egg Ag (SEA) and schistosome worm Ag (SWA) of S. japonicum enhance the accumulation of MDSCs. Ag-induced MDSCs have more potent suppressive effects on T cell responses than do control MDSCs in both in vivo S. japonicum infection and in vitro SEA- and SWA-treated mouse bone marrow cells experiments. Interestingly, the enhanced suppressive activity of MDSCs by Ag administration was coupled with a dramatic induction of the NADPH oxidase subunits gp91phox and p47phox and was dependent on the production of reactive oxygen species. Moreover, mechanistic studies revealed that the Ag effects are mediated by JAK/STAT3 signaling. Inhibition of STAT3 phosphorylation by the JAK inhibitor JSI-124 almost completely abolished the Ag effects on the MDSCs. In summary, this study sheds new light on the immune modulatory role of SEA and SWA and demonstrates that the expansion of MDSCs may be an important element of a cellular network regulating immune responses during S. japonicum infection.

This article aims to discuss the issues about Schistosoma japonicum infection in the Philippines based on the research findings of previous studies. This includes reviews about the nature of schistosomiasis, with emphasis on its effects on children. The review also discusses the mode of transmission of the parasite, etiology, and epidemiology, and relates these factors to the persistence of S. japonicum as a major health problem in the Philippines. The efforts, preventive measures, and recommended actions of the government are also mentioned and have been taken into consideration in strengthening the eradication measures against S. japonicum. This review further analyzes the risk factors associated with the infected individuals. Some measures and practices that may contribute to the prevention of S. japonicum infection are highlighted.

Background Schistosomiasis japonica is a zoonosis and presents significant public health problems in China and the Philippines. Vaccines targeting domestic animals constitute attractive control measures. Methods We conducted three vaccine trials to evaluate the protective efficacy of recombinant full-length paramyosin (rSj97) in water buffalo. Animals were immunized with 3 doses of rSj97 adjuvanted with ISA206 at 250 μg/dose or 500 μg/dose at 4 wk intervals before challenge with 1000 Schistosoma japonicum cercariae. The primary outcome was worm burden assessed by portal perfusion 8–10 weeks post challenge. Safety measures included weight, temperature, body condition score, hemogram and routine assays for hepatic and renal function. Results The three-dose regimen was well tolerated in all three trials. In the first trial, vaccinated buffalo had 51.5% lower worm burden post challenge compared to controls. In the second trial, buffalo immunized with 500 μg/dose of rSj97 had 57.8% lower worm burden compared to controls (p = 0.026). A similar but not significant reduction (60.9%) was observed with animals administered with 250ug rSj97/dose. In the third trial, buffalo immunized with a 500 μg/dose of rSj97 had 57.8% lower worm burden compared to controls (p = 0.014). Conclusions These findings indicated that rSj97 is a safe and promising vaccine candidate for schistosomiasis japonica in water buffalo.

Highly effective and safe prophylactic vaccines are urgently needed to sustainably control schistosomiasis, one of the most serious endemic zoonoses in China. In this study, we characterized adenylate kinase 1 from Schistosoma japonicum (SjAK1), a phosphotransferase that regulates cellular energy and metabolism, and evaluated its potential as a recombinant vaccine. Based on real-time quantitative PCR, western blot, and immunolocalization, SjAK1 is active throughout the life of the worm, although its expression is higher in 21-day-old schistosomula, adult worms, and eggs deposited in the host liver. Further, the enzyme accumulates in the eggshell, intestinal epithelium, integument of adult worms and in the vitellaria tissue in female worms. A 594-bp full-length complementary DNA (cDNA) encoding SjAK1 was synthesized from total RNA of 3-day-old schistosomes, and immunization with recombinant SjAK1 reduced worm burden by 50%, decreased the density of eggs deposited in the host liver by 40%, and reduced the area of granulomas in the host liver by 56%. ELISA results showed that recombinant SjAK1 also stimulated Th1 cytokines such as IL-2 and IFN-γ, but not IL-5 and IL-4. Collectively, a recombinant form of the enzyme SjAK1 elicits partial protective immunity against Schistosoma japonicum infection and the induction of Th1 cytokines. Thus, the enzyme has potential as a component of a multivalent vaccine against schistosomiasis.

SUMMARYThe current World Health Organization strategic plan targets the elimination of schistosomiasis as a public health problem by 2025 and accurate diagnostics will play a pivotal role in achieving this goal. DNA-based detection methods provide a viable alternative to some of the commonly used tests, notably microscopy and serology, for the diagnosis of schistosomiasis. The detection of parasite cell-free DNA in different clinical samples is a recent valuable advance, which provides significant benefits for accurate disease diagnosis. Here we validated a novel duplex droplet digital PCR assay for the diagnosis of Chinese (SjC) and Philippine (SjP) strains of Schistosoma japonicum infection in a mouse model. The assay proved applicable for both SjC and SjP infections and capable of detecting infection at a very early intra-mammalian stage in conveniently obtainable samples (urine and saliva) as well as in serum and feces. The target DNA copy numbers obtained in the assay showed a positive correlation with the infection burden assessed by direct traditional parasitology. The potential to detect parasite DNA in urine and saliva has important practical implications for large-scale epidemiological screening programmes in the future, particularly in terms of logistical convenience, and the assay has the potential to be a valuable additional tool for the diagnosis of schistosomiasis japonica.

Praziquantel (PZQ), a traditional helminthicide drug, has been shown to exert an anti-inflammatory effect on splenomegaly induced by schistosomiasis via regulating macrophage polarization. Meanwhile, miR-21 has been demonstrated to control macrophage polarization. However, the role of miR-21 in the regulation of macrophage polarization by PZQ in schistosomiasis is still unclear. In the present study, we found that M1-type macrophages were the predominant splenic macrophages in chronic schistosomiasis and that NLRP3 inflammasome-related molecules were upregulated. PZQ inhibited NLRP3 inflammasome in M1 macrophages and reduced the expression of miR-21. Furthermore, using the methods of quantitative real-time PCR and transfection, the downregulation of NLRP3/IL-1β by PZQ in M1 macrophages were reversed by miR-21 overexpression. These results indicated that miR-21 was involved in the inhibiting effect of PZQ on activation of NLRP3 inflammasome. Moreover, miR-21 might target Smad7 to mediate the anti-inflammatory effect of PZQ in polarized macrophages. This study provides an in-depth mechanism of PZQ in the treatment of schistosomiasis.

Urbanization increases human mobility in ways that can alter the transmission of classically rural, vector-borne diseases like schistosomiasis. The impact of human mobility on individual-level Schistosoma risk is poorly characterized. Travel outside endemic areas may protect against infection by reducing exposure opportunities, whereas travel to other endemic regions may increase risk. Using detailed monthly travel- and water-contact surveys from 27 rural communities in Sichuan, China, in 2008, we aimed to describe human mobility and to identify mobility-related predictors of S. japonicum infection. Candidate predictors included timing, frequency, distance, duration, and purpose of recent travel as well as water-contact measures. Random forests machine learning was used to detect key predictors of individual infection status. Logistic regression was used to assess the strength and direction of associations. Key mobility-related predictors include frequent travel and travel during July—both associated with decreased probability of infection and less time engaged in risky water-contact behavior, suggesting travel may remove opportunities for schistosome exposure. The importance of July travel and July water contact suggests a high-risk window for cercarial exposure. The frequency and timing of human movement out of endemic areas should be considered when assessing potential drivers of rural infectious diseases.

Background: Infection of Schistosome japonicum (S. japonicum) had been endemic in China. However, the association between Schistosome japonicum (S. japonicum) infection and the epidemiology or pathologic features of colorectal cancer was unknown. Methods: A cross-sectional survey was carried out in 220,175 participants aged 45 years and older in Songjiang County of Shanghai, an endemic region of schistosome infection. Furthermore, schistosome infection associated pathologic subtypes of colorectal cancer were also analyzed among participants. Findings: In cross-sectional survey, 9,986 subjects were defined as having previous schistosome infection, of which 249 were diagnosed as having colorectal cancer, and the overall prevalence of colorectal cancer was 2.49%. While remaining 210,189 participants without schistosome infection, 885 also suffered from colorectal cancer, and the corresponding rate was only 0.42%. Unconditional logistic regression analysis suggested a strong association between the infection and risk of colorectal cancer, with an adjusted OR of 4.248 and 95% CI of 3.656-4.935. Furthermore, compared with colorectal cancer without schistosome infection, there was a high percentage of mucinous adenocarcinoma (21.4% vs 11.8%, adjusted OR = 2.149, 95% CI = 1.474-3.134) and signet-ring cell carcinoma with schistosome infection (4.5% vs 1.1%, adjusted OR = 5.341, 95% CI = 2.145-13.296). Notably, mucinous adenocarcinoma in rectum showed a higher proportion (27.5% vs 8.2%). By contrast, signet-ring cell carcinoma had a predilection to occur in sigmoid colon (16.7% vs 0). Interpretation: S. japonicum infection is a critical risk factor and a pathologic subtype redistribution driver of colorectal cancer. Moreover, these redistributions have location-specificity and higher mucus secretion. Funding: None Declaration of Interest: We declare no competing interests. Ethical Approval: The institutional review board or ethics committee at each of the participating institutions approved the study protocol. Written informed consent was obtained from each participant before data collection.

Schistosomiasis occurs in 240 million people worldwide and is a major public health concern. Thus, early diagnosis and monitoring of schistosomiasis progression are needed to treat patients. Cell-free DNA (cfDNA) is present as fragments of parasite-derived DNA in host body fluids. Detection of this cfDNA in host blood may be a promising diagnostic marker of schistosomiasis. Therefore, in this study, we investigated the potential of internal transcribed spacer 2 (ITS2), a molecular taxonomy and barcoding marker, in diagnosing schistosomiasis using infected rabbit and mice sera. A 192 bp fragment of ITS2 was detected in the serum-isolated DNA from the infected host on different days after infection. We also determined the sensitivity of detecting ITS2 in mice with varying numbers of cercaria: cfDNA was present even in mice with low abundance of the parasite. Overall, our results show that cfDNA may be a potential tool for the early diagnosis and therapeutic evaluation of S. japonicum infection.

Schistosomiasis is a chronic parasitic disease and considered by the World Health Organization (WHO) to be second to malaria as the most devastating parasitic disease in terms of socioeconomic importance and public health impact. Characterisation of the cellular immune response to schistosomiasis is well established for Schistosoma mansoni but a comprehensive description of T cell-mediated immune responses against S. japonicum infection is lacking. Similarly, study on the effect of a particular vaccine candidate on the immune response is important as it can provide insight as to how to modulate the immune response in order to develop a more efficacious vaccine. Therefore, the aims of this project were to evaluate the T cell immune response to S. japonicum infection and following vaccination.nCBA mice were percutaneously exposed to cercariae of S. japonicum and the immune response at different time points was determined. There was a relatively robust Th1 immune response to schistosomal adult worm antigen preparation (SWAP) at the early phase of infection. However, a Th2 immune response was dominant at weeks 6 post-infection, a time point when the highest IgG response, determined by ELISA, against both SWAP and, especially, SEA was generated. The regulatory immune response was most pronounced at the early phase of the immune response followed by a rapid decline at week 6-post infection.nOur laboratory at QIMR Berghofer has targeted the ligand binding domain (LD1) of the insulin receptor (SjIR) and triose-phosphate isomerase (rSjTPI) as putative vaccine candidates against schistosomiasis japonica, both having generated encouraging levels of protection in mice. Consequently an antigen mix comprising the two vaccine proteins (rSjTPI-LD1) was prepared, and the immune response generated to it analysed in CBA mice randomly grouped into two groups. The first group was subcutaneously injected with rSjTPI-LD1 vaccine formulated with Montanide ISA 720VG (day 0) and boosted twice (on day 15 and day 30). The second group of control mice were injected with PBS and Montanide ISA 720 VG using the same immunization protocol. Two weeks after the final booster vaccination, the two groups of mice were challenged with 34 S. japonicum cercariae and the immune response at different time points was determined using IgG-ELISA and flow cytometry. There were partial but significant reductions in worm and liver egg burdens in the vaccinated animals compared with the adjuvant control group indicating the vaccine had generated partial protection in the mice. In addition, significantly higher levels of anti-rSjTPI and anti-rSjLD1 IgG antibodies were induced in the vaccinated group with the peak level occurring at week 4 post-challenge. Moreover, rSjTPI-LD1 induced both Th1 and Th2 immune responses at the early phase of the immune response mediated by CD8+ and gd T cells; a Th17-mediated response induced at a later stage. rSjTPI-LD1 significantly induced a regulatory T cell (Treg) immune response in vaccinated mice.nOverall, depletion of Tregs may improve the efficacy of rSjTP-ILD1 and further study on gd T cells with regard to vaccine-induced immunity against schistosomiasis may pave the way to the development of a more efficacious vaccine.nn

Schistosomiasis is a parasitic helminth disease that can cause severe inflammatory pathology, leading to organ damage, in humans. During a schistosomal infection, the eggs are trapped in the host liver, and products derived from eggs induce a polarized Th2 cell response, resulting in granuloma formation and eventually fibrosis. Previous studies indicated that the nucleotide-binding oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome is involved in schistosomiasis-associated liver fibrosis and that taurine could ameliorate hepatic granulomas and fibrosis caused by Schistosoma japonicum infection. Nevertheless, the precise role and molecular mechanism of the NLRP3 inflammasome and the protective effects of taurine in S. japonicum infection have not been extensively studied. In this study, we investigated the role of the NLRP3 inflammasome and the hepatoprotective mechanism of taurine in schistosoma-induced liver injury in mice. NLRP3 deficiency ameliorated S. japonicum-infection-induced hepatosplenomegaly, liver dysfunction, and hepatic granulomas and fibrosis; it also reduced NLRP3-dependent liver pyroptosis. Furthermore, taurine suppressed hepatic thioredoxin-interacting protein (TXNIP)/NLRP3 inflammasome activation in mice with S. japonicum infections, thereby inhibiting the activation of downstream inflammatory mediators such as interleukin-1β and subsequent pyroptosis. Our results suggest that the TXNIP/NLRP3 inflammasome pathway and mediating pyroptosis are involved in S. japonicum-induced liver injury and may be a potential therapeutic target for schistosomiasis treatment. In addition, taurine may be useful to alleviate or to prevent the occurrence of schistosomiasis-associated liver fibrosis.