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

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

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

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

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

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

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.

Schistosome eggs stimulate reactive oxygen species production to enhance M2 macrophage differentiation and promote hepatic pathology in schistosomiasis

Schistosomiasis is a neglected tropical disease of public health concern. The most devastating pathology in schistosomiasis japonica and mansoni is mainly attributed to the egg-induced granulomatous response and secondary fibrosis in host liver, which may lead to portal hypertension or even death of the host. Schistosome eggs induce M2 macrophages-rich granulomas and these M2 macrophages play critical roles in the maintenance of granuloma and subsequent fibrosis. Reactive oxygen species (ROS), which are highly produced by stimulated macrophages during infection and necessary for the differentiation of M2 macrophages, are massively distributed around deposited eggs in the liver. However, whether ROS are induced by schistosome eggs to subsequently promote M2 macrophage differentiation, and the possible underlying mechanisms as well, remain to be clarified during S. japonicum infection. Herein, we observed that extensive expression of ROS in the liver of S. japonicum-infected mice. Injection of ROS inhibitor in infected mice resulted in reduced hepatic granulomatous responses and fibrosis. Further investigations revealed that inhibition of ROS production in S. japonicum-infected mice reduces the differentiation of M2, accompanied by increased M1 macrophage differentiation. Finally, we proved that S. japonicum egg antigens (SEA) induce a high level of ROS production via both nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and mitochondria in macrophages. Our study may help to better understand the mechanism of schistosomiasis japonica-induced hepatic pathology and contribute to the development of potential therapeutic strategies by interfering with ROS production.

Schistosomiasis is a neglected parasitic disease of poverty that affects ~200 million people mainly in (sub)tropical regions, resulting in a massive health burden and serious morbidity. During Schistosoma japonicum (S. japonicum) or S. mansoni infection, parasite eggs are trapped in host liver and induce hepatic granulomas and fibrosis, which leads to severe liver damage, and even death of the host. In hepatic schistosomiasis, considerable amounts of ROS accumulate in granulomas surrounding liver-trapped eggs. However, whether schistosome eggs trigger the production of ROS, and if so, whether and how ROS promote hepatic pathology in host remain unknown. In this study, the authors illustrated that S. japonicum eggs evoke high production of ROS in macrophages, which is necessary for egg-mediated M2 macrophage differentiation and promotes hepatic granulomas and fibrosis in S. japonicum-infected mice. These discoveries provide a potential target regarding schistosome eggs-induced ROS production, which can be manipulated to regulate immunopathology in hepatic schistosomiasis.

Ikzf2 Regulates the Development of ICOS+ Th Cells to Mediate Immune Response in the Spleen of S. japonicum-Infected C57BL/6 Mice

Background

Th cells (helper T cells) have multiple functions in Schistosoma japonicum (S. japonicum) infection. Inducible co-stimulator (ICOS) is induced and expressed in activated T lymphocytes, which enhances the development of B cells and antibody production through the ICOS/ICOSL pathway. It remains unclear about the role and possible regulating mechanism of ICOS+ Th cells in the spleen of S. japonicum-infected C57BL/6 mice.

Methods

C57BL/6 mice were infected with cercariae of S. japonicum through the abdomen. The expression of ICOS, activation markers, and the cytokine production on CD4+ ICOS+ Th cells were detected by flow cytometry (FCM) and quantitative real-time PCR (qRT-PCR). Moreover, the differentially expressed gene data of ICOS+ and ICOS- Th cells from the spleen of infected mice were obtained by mRNA sequencing. Besides, Western blot and chromatin immunoprecipitation (ChIP) were used to explore the role of Ikzf2 on ICOS expression.

Results

After S. japonicum infection, the expression of ICOS molecules gradually increased in splenic lymphocytes, especially in Th cells (P < 0.01). Compared with ICOS- Th cells, more ICOS+ Th cells expressed CD69, CD25, CXCR5, and CD40L (P < 0.05), while less of them expressed CD62L (P < 0.05). Also, ICOS+ Th cells expressed more cytokines, such as IFN-γ, IL-4, IL-10, IL-2, and IL-21 (P < 0.05). RNA sequencing results showed that many transcription factors were increased significantly in ICOS+ Th cells, especially Ikzf2 (P < 0.05). And then, the expression of Ikzf2 was verified to be significantly increased and mainly located in the nuclear of ICOS+ Th cells. Finally, ChIP experiments and dual-luciferase reporter assay confirmed that Ikzf2 could directly bind to the ICOS promoter in Th cells.

Conclusion

In this study, ICOS+ Th cells were found to play an important role in S. japonicum infection to induce immune response in the spleen of C57BL/6 mice. Additionally, Ikzf2 was found to be one important transcription factor that could regulate the expression of ICOS in the spleen of S. japonicum-infected C57BL/6 mice.

MiR-130a-3p Alleviates Liver Fibrosis by Suppressing HSCs Activation and Skewing Macrophage to Ly6Clo Phenotype

Emerging evidences have highlighted the crucial role of microRNAs (miRNAs) in the liver cirrhosis, but the relationship between miR-130a-3p and liver cirrhosis is not entirely clear. As we all know, schistosomiasis, as one of the zoonoses, can lead to liver cirrhosis when it advances. In this study, we investigated the biological functions of miR-130a-3p on the liver fibrosis of schistosomiasis in vivo and in vitro. The mice infected with Schistosoma japonicum (S. japonicum) were treated with lentivirus vector (LV)-miR-130a-3p by hydrodynamic injection through the tail vein. Our findings showed significantly decreased expression of miR-130a-3p both in the serum of patients with cirrhosis and in the liver of mice infected with S. japonicum. The results showed that LV-miR-130a-3p could effectively enter into the liver and alleviate liver granulomatous inflammation and collagen deposition. Simultaneously, LV-miR-130a-3p-promoted macrophages presented the Ly6Clo phenotype, concomitant with the decreased expression of the tissue inhibitor of metalloproteinases (TIMP) 1, and increased the expression of matrix metalloproteinase (MMP) 2, which contributed to the dissolution of collagen. Furthermore, overexpression of miR-130a-3p not only inhibited the activation and proliferation of hepatic stellate cells (HSCs) but also induced the apoptosis of HSCs. In addition, we also confirmed that miR-130a-3p enables to bind with mitogen-activated protein kinase (MAPK) 1 and transforming growth factor-beta receptors (TGFBR) 1 and TGFBR2 genes and inhibit the expressions of these genes. Our findings suggested that miR-130a-3p might represent as the potential candidate biomarker and therapeutic target for the prognosis identification and treatment of schistosomiasis liver fibrosis.

Bnip3 interacts with vimentin, an intermediate filament protein, and regulates autophagy of hepatic stellate cells

Bnip3, which is regulated by Hif-1 in cells under oxygen deprivation, is a death related protein associated with autophagy and apoptosis. Hif-1 was reported to regulate autophagy to activate hepatic stellate cells (HSCs), while the specific molecular mechanism is vague. The possible mechanism of Hif-1 regulating autophagy of HSCs via Bnip3 was explored in this study. Bnip3 was detected in fibrotic liver tissues from humans and mice. Hif-1 was inhibited by chemical inhibitor and Bnip3 was detected in activated HSCs. The co-localization of Bnip3 and LC3B was captured by confocal microscopy and autophagic flow was assessed in Bnip3 siRNA transfected cells. Bnip3 interacted proteins were screened with mass spectrometry. The interaction of Bnip3 and vimentin was detected with co-immunoprecipitation and confocal microscopy. The results showed that Bnip3 was increased in fibrotic liver tissues and activated HSCs. Hif-1 inhibition suppressed Bnip3 expression in activated HSCs. Bnip3 was partially co-localized with autophagosomes and Bnip3 inhibition suppessed autophagy in activated HSCs. Bnip3 interacted with vimentin and Bnip3 expression was inhibited as vimentin was inhibited in activated HSCs. Conclusively, this study indicated that Bnip3 promoted autophagy and activation of HSCs, via interacting with vimentin, an intermediate filament protein with highly abundant expression in HSCs.

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

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

Spatiotemporal expression pattern of Sjfz7 and its expression comparison with other frizzled family genes in developmental stages of Schistosoma japonicum

Wnts are secreted signaling molecules that are implicated in a variety of growth-related processes. Frizzled proteins have been identified as receptors for Wnt ligands in vertebrates and invertebrates, but a functional role for dioecious flatworm Frizzleds has not been determined. To evaluate the endogenous role of Frizzled proteins during development, we have identified and characterized a Schistosoma japonicum frizzled gene (Sjfz7). We found that Sjfz7 encodes a 698 amino acid protein with typical characteristics of Frizzled proteins. The immunohistochemical localization pattern showed that Sjfz7 protein was extensively distributed in almost all tissues of S. japonicum, including subtegumental muscle cells, parenchymal cells, intestinal epithelial cells and male and female germ cells. This indicated that Sjfz7-mediated Wnt signaling might be associated with the development of musculature, intestinal tract and reproductive organs in schistosome. Comparing mRNA levels between frizzled family members showed that Sjfz7 mRNA was consistently higher in the developmental stages analyzed, suggesting that Sjfz7 may be responsible for more functional tasks than other frizzled family members. Comparing frizzled mRNA levels between not fully developed and normal worms suggested that Wnt signaling might be abnormal in not fully developed worms.

Protective Immune Responses Generated in a Murine Model Following Immunization with Recombinant Schistosoma japonicum Insulin Receptor

There is a pressing need to develop vaccines for schistosomiasis given the current heavy dependency on praziquantel as the only available drug for treatment. We previously showed the ligand domain of the Schistosoma japonicum insulin receptor 1 and 2 (rSjLD1 and 2) fusion proteins conferred solid protection in mice against challenge infection with S. japonicum. To improve vaccine efficacy, we compared the immunogenicity and protective efficacy of rSjLD1 on its own and in combination with S. japonicum triose-phosphate isomerase (SjTPI), formulated with either of two adjuvants (QuilA and montanide ISA 720VG) in murine vaccine trials against S. japonicum challenge. The level of protection was higher in mice vaccinated only with rSjLD1 formulated with either adjuvant; rSjTPI or the rSjTPI-rSjLD1 combination resulted in a lower level of protection. Mirroring our previous results, there were significant reductions in the number of female worms (30–44%), faecal eggs (61–68%), liver eggs (44–56%), intestinal eggs (46–48%) and mature intestinal eggs (58–63%) in the rSjLD1-vaccinated mice compared with the adjuvant only groups. At 6-weeks post-cercarial challenge, a significantly increased production of interferon gamma (IFNγ) in rSjLD1-stimulated splenic CD4⁺ T cells was observed in the rSjLD1-vaccinated mice suggesting a Th1-type response is associated with the generated level of protective efficacy.

Activation of nuclear factor kappa B in the hepatic stellate cells of mice with schistosomiasis japonica

Schistosomiasis japonica is a serious tropical parasitic disease in humans, which causes inflammation and fibrosis of the liver. Hepatic stellate cells (HSCs) are known to play an important role in schistosome-induced fibrosis, but their role in schistosome-induced inflammation is still largely unknown. Here, we use a murine model of schistosomiasis japonica to investigate the role that nuclear factor kappa B (NF-κB), a critical mediator of inflammatory responses, plays in schistosome-induced inflammation. We revealed that NF-κB was significantly activated in HSCs at the early stage of infection, but not at later stages. We also show that the expression levels of several chemokines regulated by NF-κB signaling (Ccl2, Ccl3 and Ccl5) were similarly elevated at early infection. TLR4 signaling, one of the strongest known inducers of NF-κB activation, seemed not activated in HSCs post-infection. Importantly, we found that levels of miR-146 (a known negative regulator of NF-κB signaling) in HSCs opposed those of NF-κB signaling, elevating at later stage of infection. These results indicate that HSCs might play an important role in the progression of hepatic schistosomiasis japonica by linking liver inflammation to fibrosis via NF-κB signaling. Moreover, our work suggests that miR-146 appeared to regulate this process. These findings are significant and imply that manipulating the function of HSCs by targeting either NF-κB signaling or miR-146 expression may provide a novel method of treating hepatic schistosomiasis japonica.

[Prokaryotic expression and function analysis of Schistosoma japonicum calpain]

OBJECTIVE

To clone and express recombinant calpain of Schistosoma japonicum (Sjcalpain), observe the distribution of Sjcalpain in S. japonicum cercariae and analyze its role in skin invasion.

METHODS

The primers were designed according to the full-length sequence of calpain (GenBank accession No. AB016726). The genes encoding catalytic domain and Ca2+ binding domain of Sjcalpain were amplified by PCR, and the target fragments were subcloned into pET-28a. The recombinant proteins were expressed in E. coli BL21 (DE3) and purified by Ni-NTA resin. The rabbit polyclonal antibodies were prepared with the two purified recombinant proteins by immunizing New Zealand white rabbits. ELISA was used to detect the titer of rabbit antiserum. Immunolocalization was used to investigate the distribution of Sjcalpain in S. japonicum cercariae. Cercariae were incubated with specific inhibitor before infection of mice and the worm reduction rate was calculated.

RESULTS

The recombinant expression vector Sjcalpain catalytic domain/pET28a and Sjcalpain Ca2+ binding domain/pET28a were constructed and the recombinant proteins were successfully expressed in E. coli BL21 (DE3) (about M(r) 43 000 and M(r) 39 000, respectively). The two target proteins were expressed as inclusion bodies. The purified target proteins were obtained through Ni-NTA affinity purification. ELISA result showed that the titer of prepared rabbit polyclonal antibodies was higher than 1 : 80 000. Immunolocalization study demonstrated that Sjcalpain protein was mainly expressed in the head of cercariae. Inhibition assays suggested that the average number of adult worms in calpain inhibitor-incubation group and control group was 19 and 23, respectively, with a worm reduction rate of 17.4%.

CONCLUSION

Sjcalpain is mainly expressed in the head of S. japonicum cercariae. Inhibition of Sjcalpain could reduce the number of invading cercariae in infected mice, which suggest that Sjcalpain may play a role in skin invasion by cercariae.

[Expression of Toll-like receptors 2 and 6 in mice liver during Schistosoma japonicum infection]

OBJECTIVE

To investigate the expression of hepatic Toll-like receptor 1 (TLR1), TLR2 and TLR6 on mice with Schistosoma japonicum infection.

METHODS

Fifty BALB/c mice were infected with 20 +/- 3 S. japonicum cercariae through abdominal skin. At 6 weeks post-infection, the mice (n = 10) in treatment group were administered intragastrically with praziquantel [250 microg/(g x d)] for 3 d. The livers of mice (n = 10) were collected at pre-infection and 5, 6, 8 and 12 weeks post-infection, and then the mRNA expression levels of hepatic TLR1, TLR2, TLR6 gene were detected with reverse transfer PCR. Hepatic TLR2, TLR6 protein levels were detected by immunohistochemical staining.

RESULTS

The mRNA levels of TLR1, TLR2, and TLR6 on 5, 6, 8 and 12 weeks post infection were significantly higher than that of uninfected mice. After praziquantel treatment, the mRNA level of TLR2 and TLR6 in murine liver of treatment group was lower than that of infection group, but the level of TLR1 mRNA had no obvious change. Furthermore, immunohistochemistry results revealed that the expression of TLR2 and TLR6 proteins in murine liver was up-regulated at 5, 6, 8 and 12 weeks post-infection. After praziquantel treatment, the percentage of TLR2 positive area in liver of infected mice without and with praziquantel treatment were (44.2 +/- 4.3)%, (8.8 +/- 3.1)%, respectively, and TLR2 protein level was considerably down-regulated (P < 0.01). The percentage of TLR6 positive area in liver of infected mice without and with praziquantel treatment was (48.4 +/- 5.4)%, (37.4 +/- 3.5)%, respectively, and TLR6 level decreased slightly (P < 0.05).

CONCLUSION

The expression level of TRL2 and TLR6 in murine liver increases after Schistosoma japonicum infection. While compared with TLR2, the role of TLR6 in this progress is a weaker one.

[Therapeutic effect of resveratrol as well as resveratrol combined with praziquantel on the liver fibrosis due to Schistosoma japonicum infection in mice]

OBJECTIVE

To study the therapeutical effect and mechanisms of resveratrol and its combination with praziquantel on the liver fibrosis due to Schistosoma japonicum infection.

METHODS

Eighty mice infected with 25 S. japonicum cercariae for 6 weeks were randomly divided into four groups named as praziquantel group (A), resveratrol group (B), resveratrol+praziquantel group (C) and infection group (D). Mice in groups A and B were treated with praziquantel [500 mg/(kg x d)] for 2 d, and resveratrol [20 mg/(kg x d)] for 6 weeks, respectively. Mice in group C were treated with resveratrol [20 mg/(kg x d)] for 6 weeks after praziquantel treatment [500 mg/(kg x d)x 2 d]. Group D served as infection control. Twenty normal mice were taken as normal control group (Group E). At the 12th week post-infection, all mice were sacrificed and the liver tissues were removed. Histopathological changes were observed in the liver of all groups. RT-PCR was used to detect the relative VEGF mRNA level in liver tissue. Maleic dialdehyde (MDA) content and superoxide dismutase (SOD) activity in liver were measured by ELISA. The expressions of VEGF, type I and type III collagen were examined by immunohistochemistry.

RESULTS

After treatment, the degrees of liver fibrosis in groups A, B and C decreased. The hepatic expression of VEGF mRNA and VEGF protein levels in groups A (0.37 +/- 0.06, 0.69 +/- 0.42), B (0.23 +/- 0.01, 0.38 +/- 0.42), C (0.11 +/- 0.00, 0.12 +/- 0.17) and E (0.06 +/- 0.03, 0.04 +/- 0.02) were lower than that of group D (0.60 +/- 0.03, 0.97 +/- 0.36) (P < 0.01), those in groups A and B were significantly lower than that of group C (P < 0.01 or P < 0.05), and those in group A were lower than in group B (P < 0.05). There was no significant difference in liver SOD activity and MDA content between group A(13.56 +/- 2.56, 7.62 +/- 2.30) and group B(14.28 +/- 1.56, 6.63 +/- 2.31)(P > 0.05). Compared with group C (22.36 +/- 1.55, 2.31 +/- 1.31), mice in groups A and B exhibited decreased an SOD activity, but increased MDA content (P < 0.05). SOD activity of groups A, B, and C was higher than that of group D (P < 0.05 or P < 0.01), and MDA content in the above three groups was lower than that of group D (P < 0.05 or P < 0.01).

CONCLUSION

Resveratrol has an antifibrogenic effect through inhibiting the expression of VEGF and reducing oxidative stress in mice with Schistosoma japonicum egg-induced liver fibrosis. Resveratrol and praziquantel show a synergistic action in antifibrosis treatment.

[Expression of vascular growth factors in intestinal tissues in colorectal carcinoma patients with schistosomiasis japonica]

OBJECTIVE

To investigate the differences of mRNA quantitation and protein expression of vascular growth factors including platelet-derived endothelial cell growth factor (PD-ECGF) and vascular endothelial growth factor (VEGF) in intestinal tissues in colorectal carcinoma patients with and without schistosomiasis.

METHODS

Thirty colorectal carcinoma patients with schistosomiasis and 30 colorectal carcinoma patients without schistosomiasis were included in this study. The mRNA quantitation and protein expression of PD-ECGF and VEGF in the normal tissue, peri-carcinoma tissue as well as carcinoma tissue obtained from surgical specimens were detected by qRT-PCR and Western blot.

RESULTS

The mRNA relative quantitations of PD-ECGF in normal tissue, peri-carcinoma tissue and carcinoma tissue in the colorectal carcinoma patients with schistosomiasis were 1.726, 1.766 and 2.729 times to those in the colorectal carcinoma patients without schistosomiasis, respectively. The corresponding ones of VEGF were 2.138, 1.831 and 3.376 times, respectively. The protein expression levels of PD-ECGF and VEGF in normal tissue, peri-carcinoma tissue and carcinoma tissue were higher in the colorectal carcinoma patients with schistosomiasis than in the colorectal carcinoma patients without schistosomiasis.

CONCLUSIONS

The expressions of vascular growth factors including PD-ECGF and VEGF are higher in the colorectal carcinoma patients with schistosomiasis than in the colorectal carcinoma patients without schistosomiasis. Therefore, schistosomiasis may be one of the risk factors of colorectal cancer.

[Expression of Smad proteins in the process of liver fibrosis in mice infected with Schistosoma japonicum]

OBJECTIVE

To study the expression of Smads proteins involved in TGF-beta1 signal transduction during the process of liver fibrosis in BALB/c mice infected with Schistosoma japonicum.

METHODS

Thirty-four BALB/c mice were each infected with (20 +/- 1) S. japonicum cercariae. The mice were sacrificed at 8, 12, 16 and 24 weeks postinfection. Ten healthy BALB/c mice served as normal control group. The liver tissues were fixed in 10% formaldehyde for histology and immunohistochemistry assay. The single-egg granuloma area was measured in hematoxylin-eosin stain section. The degree of liver fibrosis was determined by Sirius red staining. Immunohistochemistry was used to observe the expression of Smad protein.

RESULTS

The area of single-egg granuloma peaked at 8th week post-infection [(533 +/- 1.03) mm2], and with time passing, the area diminished, and the area of granuloma reduced to (2.94 +/- 1.69) mm2 at 24 weeks post-infection. The difference was significant among the 4 periods after infection in single-egg granuloma area (P < 0.05). Collagen fibers appeared around granulomas at 8 weeks (2.03 +/- 0.52) and increased gradually. At 24 weeks post-infection, the degree of liver fibrosis reached a peak (6.90 +/- 1.57), and the liver fibrosis degree was significantly different among infection groups (P < 0.05). Immunohistochemistry showed low expression level of Smad2/3 and Smad7 and inconspicuous level of Smad4 in livers of the normal mice. The expression of Smad2/3 was found mostly in the cytoplasm and nucleus of cells around granulomas at 8th week post-infection, and the positive area of Smad2/3 was (7.24 +/- 1.64)% by semi-quantity. At 12 weeks post-infection, the Smad2/3 protein expression level around granulomas and liver sinus reached the peak [(10.01 +/- l.07)%], and there was significant difference between infection groups and the control [(2.13 +/- 0.32)%]. A significant difference in the Smad2/3 protein expression level was found between 12 weeks post-infection group and 8 weeks or 16 weeks post-infection groups. The expression level of Smad4 was (8.81 +/- 1.13)% at 8th week post-infection, higher than that in the control [(4.83 +/- 1.15)%] (P < 0.05). There was no difference among the infected mice at different periods in the level of Smad4 (P > 0.05). After 8 weeks post infection, Smad7 protein sparsely appeared around the granuloma [(4.15 +/- 1.26)%] while it disappeared around liver sinus. At 12 weeks post-infection, the level of Smad7 protein was higher [(6.34 +/- 1.5)%], but with prolonged infection time, no significant difference was revealed (P > 0.05). The level of Smad7 in infected mice was higher than that in the control (P < 0.05).

CONCLUSION

Resylts show high expression for Smad2/3 and Smad7 and low expression level of Smad4 during the process of liver fibrosis in BALB/c mice infected with Schistosoma japonicum.

Exogenous bone morphogenetic protein-7 reduces hepatic fibrosis in Schistosoma japonicum-infected mice via transforming growth factor-β/Smad signaling

AIM: To investigate the antifibrotic effects of bone morphogenetic protein-7 (BMP-7) on Schistosoma japonicum (S. japonicum)-induced hepatic fibrosis in BALB/C mice.

METHODS: Sixty BALB/C mice were randomly divided into three groups, including a control group (group A, n = 20), model group (group B, n = 20) and BMP-7 treated group (group C, n = 20). The mice in group B and group C were abdominally infected with S. japonicum cercariae to induce a schistosomal hepatic fibrosis model. The mice in group C were administered human recombinant BMP-7. Liver samples were extracted from mice sacrificed at 9 and 15 wk after modeling. Hepatic histopathological changes were assessed using Masson’s staining. Transforming growth factor-beta 1 (TGF-β1), alpha-smooth muscle actin (α-SMA), phosphorylated Smad2/3 (pSmad2/3) and Smad7 protein levels and localization were measured by Western blotting and immunohistochemistry, respectively, and their mRNA expressions were detected by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS: The schistosomal hepatic fibrosis mouse model was successfully established, as the livers of mice in group B and group C showed varying degrees of typical schistosomal hepatopathologic changes such as egg granuloma and collagen deposition. The degree of collagen deposition in group C was higher than that in group A (week 9: 22.95 ± 6.66 vs 2.02 ± 0.76; week 15: 12.84 ± 4.36 vs 1.74 ± 0.80; P < 0.05), but significantly lower than that in group B (week 9: 22.95 ± 6.66 vs 34.43 ± 6.96; week 15: 12.84 ± 4.36 vs 18.90 ± 5.07; P < 0.05) at both time points. According to immunohistochemistry data, the expressions of α-SMA, TGF-β1 and pSmad2/3 protein in group C were higher than those in group A (α-SMA: week 9: 21.24 ± 5.73 vs 0.33 ± 0.20; week 15: 12.42 ± 4.88 vs 0.34 ± 0.27; TGF-β1: week 9: 37.00 ± 13.74 vs 3.73 ± 2.14; week 15: 16.71 ± 9.80 vs 3.08 ± 2.35; pSmad2/3: week 9: 12.92 ± 4.81 vs 0.83 ± 0.48; week 15: 7.87 ± 4.09 vs 0.90 ± 0.45; P < 0.05), but significantly lower than those in group B (α-SMA: week 9: 21.24 ± 5.73 vs 34.39 ± 5.74; week 15: 12.42 ± 4.88 vs 25.90 ± 7.01; TGF-β1: week 9: 37.00 ± 13.74 vs 55.66 ± 14.88; week 15: 16.71 ± 9.80 vs 37.10 ± 12.51; pSmad2/3: week 9: 12.92 ± 4.81 vs 19.41 ± 6.87; week 15: 7.87 ± 4.09 vs 13.00 ± 4.98; P < 0.05) at both time points; the expression of Smad7 protein in group B was higher than that in group A and group C at week 9 (8.46 ± 3.95 vs 1.00 ± 0.40 and 8.46 ± 3.95 vs 0.77 ± 0.42; P < 0.05), while there were no differences in Smad7 expression between the three groups at week 15 (1.09 ± 0.38 vs 0.97 ± 0.42 vs 0.89 ± 0.39; P > 0.05). Although minor discrepancies were observed, the results of RT-PCR and Western blotting were mainly consistent with the immunohistochemical results.

CONCLUSION: Exogenous BMP-7 significantly decreased the degree of hepatic fibrosis in both the acute and chronic stages of hepato-schistosomiasis, and the regulatory mechanism may involve the TGF-β/Smad signaling pathway.

Schistosoma japonicum egg antigen up-regulates fibrogenesis and inhibits proliferation in primary hepatic stellate cells in a concentration-dependent manner

AIM: To investigate the effects of different concentrations of Schistosoma japonicum (S. japonicum) egg antigen on fibrogenesis and apoptosis in primary hepatic stellate cells (HSCs).

METHODS: A mouse model of schistosomiasis-associated liver fibrosis (SSLF) was established by infecting mice with schistosomal cercaria via the abdomen. HSCs were isolated from SSLF mice by discontinuous density gradient centrifugation, and their identity was confirmed by immunofluorescence double staining of α-smooth muscle actin (α-SMA) and desmin. The growth inhibitory effect and 50% inhibitory concentration (IC50) of S. japonicum egg antigen for primary HSCs (24 h) were determined using a cell counting kit-8 (CCK-8) assay. The expression levels of α-SMA, matrix metalloproteinase-9 (MMOL/LP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in HSCs in response to different concentrations of S. japonicum egg antigen were detected by Western blotting and real-time reverse transcription-polymerase chain reaction. The levels of phospho-P38 (P-P38), phospho-Jun N-terminal kinase (P-JNK) and phospho-Akt (P-AKT) in HSCs were detected by Western blotting.

RESULTS: An SSLF mouse model was established, and primary HSCs were successfully isolated and cultured. S. japonicum egg antigen inhibited HSC proliferation in a concentration-dependent manner. The IC50 of the S. japonicum egg antigen was 244.53 ± 35.26 μg/mL. S. japonicum egg antigen enhanced α-SMA expression at both the mRNA and protein levels and enhanced TIMP-1 expression at the mRNA level in HSCs (P < 0.05), whereas the expression of MMOL/LP-9 was attenuated at both the mRNA and protein levels in a concentration-dependent manner (P < 0.05). A high concentration of S. japonicum egg antigen enhanced P-P38, P-JNK and P-AKT activation (P < 0.05). The changes in α-SMA and MMOL/LP-9 expression induced by S. japonicum egg antigen were closely correlated with P-P38 and P-JNK activation (P < 0.05). The attenuation of MMOL/LP-9 was also correlated with P-AKT activation (P < 0.05), but the increase in α-SMA expression was not. TIMP-1 expression was not correlated with P-P38, P-JNK or P-AKT activation.

CONCLUSION: S. japonicum egg antigen promotes fibrogenesis, activates the P38/JNK mitogen-activated protein kinase and AKT/PI3K signaling pathways and inhibits proliferation in primary HSCs isolated from SSLF mice in a concentration-dependent manner.

[Effects of Schistosoma japonicum heat-shock protein 40 on macrophage activation]

OBJECTIVE

To clone and express heat-shock protein 40 gene of Schistosoma japonicum (SjHSP40) and analyze its effect on macrophage activation.

METHODS

The fragment of gene encoding SjHSP40 was amplified by PCR. The gene was sub-cloned into the prokaryotic expression vector pGEX-6P-1. The recombinant plasmid pGEX-6P-1-SjHSP40 was transformed into E. coli BL21 (DE3) and induced with IPTG. The recombinant protein was purified with Glutathione-Sepharose 4B resin and analyzed by SDS-PAGE and Western-blot. The fusion protein of GST-SjHSP40 was loaded to the macrophage cell-line RAW264.7 for 48 h. Following that, the surface molecules of the macrophages were analyzed by flow cytometry.

RESULTS

DNA sequencing showed that the recombinant plasmid, pGEX-6P-1-SjHSP40, was successfully constructed. The fusion protein of GST-SjHSP40 was induced, purified and specifically recognized by anti-GST antibody. Compared to GST and medium control groups, this fusion protein significantly induced the expression of co-stimulatory molecules (CD40, CD80, and CD86) and MHC-II on the surface of the macrophages.

CONCLUSIONS

SjHSP40 significantly up-regulates the expression of co-stimulatory molecules and MHC-II on the surface of the macrophages. These data indicate that SjHSP40 may initiate macrophage activation.

[Dynamic expressions of IL-17 and IL-23 in mice infected with Schistosoma japonicum]

OBJECTIVE

To investigate the dynamic expressions of IL-17 and IL-23 in mice with Schistosoma japonicum infection.

METHOD

A murine model of the infection of S. japonicum was established. The suspension of spleen cells incubated with ConA was collected at 0, 1, 2, 4, 6, 8 and 10 weeks post-infection. Sandwich ELISA and RT-PCR were used to measure the expressions of IL-17A and IL-23p19 on protein and mRNA level.

RESULTS

The dynamic changes of IL-17A and IL-23p19 showed a positive correlation. The level of IL-17A increased and reached the peak at 1 week after the infection, reduced at 4 weeks after the infection, and was even lower at 8 weeks post-infection. The level of IL-17 mRNA increased at 1 week post-infection, and then decreased gradually at 2 weeks post-infection. Being consistent with the dynamic expression of IL-17A, the IL-23p19 expression increased at 1 week post-infection, went up to the peak at 2 weeks post-infection, and gradually reduced into the normal level at 4 weeks. However, the expression of IL-23p19 mRNA fluctuated in the normal range, increased at 4 weeks post-infection, and reached the peak at 6 weeks post-infection.

CONCLUSIONS

IL-17 and IL-23 are of co-expression in the mice after schistosome infection. There is a significant increase in the early stage of the infection. IL-17 and IL-23 may play important roles during the immune process in the very early stage of Schistosoma infection.

[Expression of transforming growth factor-beta1 and connective tissue growing factor in schistosomal hepatic fibrosis of mice]

OBJECTIVE

To establish the model of hepatic fibrosis in mice infected with Schistosoma japonicum and observe the expression of transforming growth factor-beta1 (TGF-beta1) and connective tissue growing factor (CTGF) in mice model.

METHODS

Thirty BALB/c mice were randomly assigned to control group and model group. Each mouse of model group was infected with (30 +/- 1) S. japonicum cercariae through the abdominal skin. Serum samples were collected at 4, 6, 8, 10, and 12 weeks after infection, and were analyzed for the levels of ALT and AST. Pathological changes and proliferation of hepatic collagen fibers in liver tissue were observed after HE staining and Masson staining. Immunohistochemistry and real-time PCR were used to detect the protein and mRNA expression of CTGF and TGF-pl.

RESULTS

6-12 weeks after infection, there was significant difference in ALT and AST between model group and control group (P43.05). At 12th week, ALT [(173.53 +/- 31.12) U/I] and AST [(301.00 +/- 34.87) U/LI in model group were higher than those in control group [(42.00 +/- 3.53) and 96.58 +/- 11.26) U/L] . In model group, egg granulomas formed in the liver, and the formation of hepatic fibrosis was significant in portal areas, and there was tree-like hepatic fibrosis around the portal vein branch. 8 weeks after infection, hepatic fibrosis area in mice of model group increased considerably, and there was significant difference in percentage of positive area of collagen between 12th week [(23.83 +/- 1.68) %] and control group [(1.23 +/- 0.14) %] (P < 0.05). 10 and 12 weeks after infection, the percentage of positive area of TGF-beta1 [(22.34 +/- 2.58)% and (25.82 +/- 3.01) %] and CTGF [(1 l.32 +/- 2.44)% and (14.51 +/- 2.05) %] was higher respectively than that of the control [(2.56 +/- 0.87)%, and (1.09 +/- 0.73)% (P < 0.05). 6, 8, 10, and 12 weeks after infection, both TGF-beta1 and CTGF mRNA increased gradually, higher than that in control group (P < 0.05). 10 weeks after infection, TGF-beta1 mRNA relative transcription level was the highest (0.0721 +/- 0.0187) and it was 0.0089 +/- 0.0037 in control group. CTGF mRNA relative transcription level reached the highest value (0.1136 +/- 0.0365) in 12 weeks after infection, while it was 0.0293 +/- 0.0184 in control group. CTGF mRNA expression was positively correlated with the duration of infection (r = 0.927, NO.05).

CONCLUSION

The area and cell types of TGFb1 positive expression is the same as that of CTGF in liver tissue of schistosome infected mice (BALB/c). CTGF mRNA expression is significantly related to the duration of infection, but it is not the case for TGFbl.

[Effect of N-acetylcysteine on malondialdehyde and superoxide dismutase in hepatic tissue of mice with Schistosomiasis japonica]

90 mice were randomly divided into six groups: normal control, infected control, long-term drug use group 1 (L1), long-term drug use group 2 (L2), short-term drug use group 1 (S1) and short-term drug use group 2 (S2). Mice in all groups except those in the normal control group were infected with 30 cercariae of Schistosoma japonicum through abdominal skin. N-acetylcysteine (NAC) solution was orally given to mice in L1 and L2 groups, 200 mg/kg and 400 mg/kg, respectively, 2 times/d from the day of infection, while for S1 and S2 groups, 200 mg/kg and 400 mg/kg, respectively, 2 times/d from the 42th day after L2 infection. Mice in the groups of normal control, infected control, L1 and L2 were sacrificed either on day 42 or day 56 after infection, while those in S1 and S2 were sacrificed on day 56 after infection. Number and area of the single egg granuloma were measured with computer image analysis software. The concentration of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in serum and hepatic tissue were detected. The number of "+" single egg granulomas in the liver of mice in L1 was the fewest by 3.04, followed by those in S1, by 4.87. The results indicated that the level of MAD in hepatic tissue of L2 (9.2-9.3 nmol/mg)was markedly lower than that of L1 (P < 0.05), and the level of SOD in hepatic tissue of L1 was 170.00-190.00 U/(g x pro), similar to those of S1 and L2 at the 42th day (P > 0.05), but the level in L2 at the 56th day was close to that of S2 (P > 0.05). Hence, NAC may retard the formation of single egg granulomas in the liver of infected mice, and may regulate the concentration of MDA and the activity of SOD in the liver.

Identification of in vivo protein phosphorylation sites in human pathogen Schistosoma japonicum by a phosphoproteomic approach

Schistosome is the causative agent of human schistosomiasis and related animal disease. Reversible protein phosphorylation plays a key role in signaling processing that are vital for a cell and organism. However, it remains to be undercharacterized in schistosomes. In the present study, we characterized in vivo protein phosphorylation events in different developmental stages (schistosomula and adult worms) of Schistosoma japonicum by using microvolume immobilized metal-ion affinity chromatography (IMAC) pipette tips coupled to nanoLC-ESI-MS/MS. In total, 127 distinct phosphorylation sites were identified in 92 proteins in S. japonicum. A comparison of the phosphopeptides identified between the schistosomula and the adult worms revealed 30 phosphoproteins co-detected in both of the two worms. These proteins included several signal molecules and enzymes such as 14-3-3 protein, cysteine string protein, heat shock protein 90, epidermal growth factor receptor pathway substrate 8, proliferation-associated protein 2G4, peptidyl-prolyl isomerase G, phosphofructokinase and thymidylate kinase. Additionally, the phosphorylation sites were examined for phosphorylation specific motif and evolutionarily conservation. The study represents the first attempt to determine in vivo protein phosphorylation in S. japonicum by using a phosphoproteomic approach. The results by providing an inventory of phosphorylated proteins may facilitate to further understand the mechanisms involved in schistosome development and growth, and then may result in the development of novel vaccine candidates and drug targets for schistosomiasis control.

Identification of phage display peptides with affinity for the tegument of Schistosoma japonicum schistosomula

Peptides, bound to the tegument of live Schistosoma japonicum schistosomula, were differentially screened by phage display in vitro using three rounds of reverse absorption and bio-panning. Three M13 phage peptides were isolated and identified by determination of their recovery rate, immunohistochemical localization, immunoblot analysis, and their anti-schistosomal effects in vivo and in vitro. Of the three, M13 phage peptide ZL4 (MppZL4, YSGLQDSSLRLR, 1.4kDa, pI 8.8) bound to the tegument of mechanically transformed schistosomula and to other developmental stages of S. japonicum from the mammalian host. By contrast, MppZL4 did not bind to the surface of cercariae. To further examine its binding properties, MppZL4 was conjugated to Rhodamine B (RhB-YSGLQDSSLRLR, RhB-ZL4) and a peptide control (RhB-AIPYFSGILQWR, RhB-12P) was similarly synthesized. The binding capacities of RhB-ZL4 to the surface membrane of S. japonicum schistosomula in vitro and of S. japonicum adult worms in vivo were examined and revealed specificity for binding. When examined for anti-parasite activity, both MppZL4 and RhB-ZL4 exhibited a potent schistosomicidal effect in vitro. Further MppZL4 also affected the growth and development of schistosomula in vivo. These findings extend previous studies showing that phage display techniques can recover polypeptides that bind specifically to living schistosomes and, moreover, that these bound peptides have the potential to inhibit key physiological processes in these parasites. Our findings suggest further that ectogenic polypeptides, which can bind to the tegument of S. japonicum, might be adapted as vectors to deliver experimental probes and/or pharmacologically relevant compounds to the schistosome tegument, including drugs and immunological mediators.

[Effects of paeoniflorin on expressions of CTGF, PDGF and TNF-alpha in mice with hepatic fibrosis due to Schistosoma japonicum infection]

OBJECTIVE

To observe the effects of paeoniflorin on the expressions of CTGF and PDGF in liver tissue of fibrosis and the serum level of TNF-alpha in mice infected with Schistosoma japonicum, and to explore the protective effect and its mechanisms of paeoniflorin on liver fibrosis.

METHODS

Kunming mice were divided randomly into 5 groups, namely normal control group (Group A), paeoniflorin groups (Group B, C, D) and infected control group (Group E). The mice in Group B-E were infected with cercariae of Schistosoma japonicum, and then they were treated with praziquantel (400 mg/kg per day) for 2 days after 6 weeks. After that, the mice in Group B, C, D were given paeoniflorin with a dose of 30, 60, 120 mg/(kg x d), respectively. After 8 weeks of paeoniflorin treatment, all the mice were killed, and their livers and serum were obtained. Hematoxylin and eosin stain and Masson stain were used to observe the degree of hepatic fibrosis. Immunohistochemical staining was performed to detect the expressions of CTGF and PDGF in liver tissue. The serum level of TNF-alpha was detected by ELISA.

RESULTS

The expression levels of CTGF and PDGF proteins in liver tissue and the serum level of TNF-alpha of the mice in the high dosage paeoniflorin treatment group (Group D) were significantly lower than those in the infected control group (P < 0.05).

CONCLUSIONS

The effects of paeoniflorin on hepatic fibrosis induced by Schistosoma japonicum infection depends on its dosage. Paeoniflorin may exert its effects by inhibiting the serum level of TNF-alpha and down regulating the expression of CTGF and PDGF proteins.

[Anti-hepatofibrosis effect of fasudil hydrochloride on Schistosoma japonicum-infected mice]

OBJECTIVE

To investigate the anti-fibrotic effect of fasudil hydrochloride on Schistosoma japonicum-infected mice, and the effect of fasudil hydrochloride on hepatic stellate cells (HSCs).

METHODS

Thirty female BALB/c mice were randomly divided into 3 groups viz, normal control group (NC group), infection group, and experiment group. Mice in both infection group and experiment group were infected with (14:2) cercariae of S japonicum. At 6 weeks post infection, mice in experiment group were intraperitoneally injected with fasudil hydrochloride (10 mg/kg) twice a day for 7 d, while mice in NC group and infection group received the same volume of physiological saline. All mice were sacrificed 12 h after the last injection. Livers from NC group and infection group were used to prepare tissue sections for hematoxylin and eosin (HE) staining, or sirius red staining, and observed under light microscope. Livers from all three groups were used to detect content of hydroxyproline (Hyp) and the mRNA expressions of alpha-smooth muscle actin (alpha-SMA), type I collagen alpha1 (Col1alpha1) and epithelial cell transforming sequence 2 (Ect2). HSCs from mice in all three groups were isolated to detect the mRNA levels of alpha-SMA, Col1alpha1, and Ect2, respectively.

RESULTS

Pathological sections showed that in livers from mice in infection group, inflammatory cells infiltrated and collagenous fibre proliferated around portal areas and egg granulomas. The content of Hyp in liver from mice of NC group, infection group, and experiment group was (279.7 +/- 21.2) microg, (528.0 +/- 15.0) microg, and (355.4 +/- 22.6) microg, respectively. The content of Hyp in livers from mice of experiment group was significantly reduced compared to infection group (P < 0.01). The mRNA expression of alpha-SMA, Col1alpha1 and Ect2 in livers and HSCs from mice in experiment group were significantly down-regulated compared to infection group (P < 0.05).

CONCLUSION

Fasudil hydrochloride can depress hepatofibrosis in Schistosoma japonicum-infected mice.

New insight into the antifibrotic effects of praziquantel on mice in infection with Schistosoma japonicum

BACKGROUND

Schistosomiasis is a parasitic disease infecting more than 200 million people in the world. Although chemotherapy targeting on killing schistosomes is one of the main strategies in the disease control, there are few effective ways of dealing with liver fibrosis caused by the parasite infection in the chronic and advanced stages of schistosomiasis. For this reason, new strategies and prospective drugs, which exert antifibrotic effects, are urgently required.

METHODS AND FINDINGS

The antifibrotic effects of praziquantel were assessed in the murine models of schistosomiasis japonica. Murine fibrosis models were established by cutaneous infection with 14 ± 2 Schistosoma japonicum cercariae. Then, the mice of both chronic (8 weeks post-infection) and advanced (15 weeks post-infection) schistosomiasis were treated by gavage of praziquantel (250 mg/kg, once daily for 3 days) to eliminate worms, and followed by praziquantel anti-fibrosis treatment (300 mg/kg, twice daily for 30 days). The fibrosis-related parameters assessed were areas of collagen deposition, content of hydroxyproline and mRNA expressions of Col1α1, Col3α1, α-SMA, TGF-β, MMP9, TIMP1, IL-4, IL-10, IL-13 and IFN-γ of liver. Spleen weight index, alanine aminotransferase activity and liver portal venous pressure were also measured. The results showed that anti-fibrosis treatment improved liver fibrosis, splenomegaly, hepatic function, as well as liver portal hypertension. In order to confirm the anti-fibrotic properties of praziquantel, we established a CCL(4)-induced model and revealed that CCL(4)-induced liver fibrosis was inhibited by PZQ treatment for 30 days. Furthermore, we analyzed the effects of praziquantel on mouse primary hepatic stellate cells (HSCs). It is indicated that mRNA expressions of Col1α1, Col3α1, α-SMA, TGF-β, MMP9 and TIMP1 of HSCs were all inhibited after praziquantel anti-parasite treatments.

CONCLUSIONS

The significant amelioration of hepatic fibrosis by praziquantel treatment validates it as a promising drug of anti-fibrosis and offers potential of a new chemotherapy for hepatic fibrosis resulting from schistosomiasis.

[The protective effect of chronic schistosoma japonica infestation against sepsis in mice]

OBJECTIVE

To preliminarily study the protective effect of chronic schistosoma japonica (SJ) infestation against sepsis in mice and its mechanism.

METHODS

BALB/c male mice were used, and the experiment was divided into three parts. Experiment 1: chronic SJ infestation model was reproduced by SJ cercaria inoculation through abdominal skin for 8 weeks. Twenty mice were randomly grouped into normal group (n=10) and SJ group (n=10). The levels of interleukins (IL-4, IL-10),tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in serum were detected by enzyme linked immunosorbent assay (ELISA). Real-time polymerase chain reaction (PCR) was employed to detect the levels of IL-10 mRNA and TNF-αmRNA in abdominal macrophages. This experiment was meant to evaluate immune state in mice with chronic SJ infestation. Experiment 2: lipopolysaccharide (LPS) was intraperitoneally injected to reproduce sepsis model. Thirty mice were randomly grouped into LPS group (n=15) and SJ-LPS group (n=15). The levels of cytokines were determined by ELISA at 0, 24, 48 and 72 hours after LPS injection. This experiment was meant to detect the effect of chronic SJ infestation in mice during the septic process. Experiment 3: two types of sepsis model were reproduced by cecal ligation and puncture (CLP) and LPS injection, respectively. The survival rate of mice with chronic SJ infestation in 72 hours in either type of sepsis was evaluated.

RESULTS

Experiment 1: compared with normal group [IL-4 (56.32±8.66) ng/L, IL-10 (48.17±7.23) ng/L], chronic SJ infestation showed an increase in serum IL-4 [(151.35±12.24) ng/L] and IL-10 [(133.22±11.09) ng/L, both P<0.05]. Chronic SJ infestation also resulted in an increase in IL-10 mRNA expression (SJ group 4.46±1.82, normal group 1.52±0.60) and inhibited TNF-α mRNA expression (SJ group 1.61±0.93, normal group 2.32±1.03) in abdominal macrophages (both P<0.05), indicating that macrophages could be differentiated into alternative activated macrophages. Experiments 2 and 3 showed that the levels of serum IL-4 and IL-10 were increased at 0 hour after LPS injection, and then gradually decreased in SJ-LPS group, but the levels were still higher than those in LPS group at 72 hours [IL-4 (ng/L): 92.2±7.6 vs. 41.5±4.5; IL-10 (ng/L): 92.1±7.8 vs. 35.6±4.0, both P<0.05]; the levels of TNF-α and IFN-γ were increased at 24 hours, and then decreased in SJ-LPS group, and the levels were lower than those in LPS group at 72 hours [TNF-α (ng/L): 82.9±5.6 vs. 91.5±5.2; IFN-γ (ng/L): 44.1±4.8 vs. 52.6±4.0, both P<0.05]. Therefore, chronic SJ infestation could improve the survival rate of mice with sepsis induced by CLP or LPS (CLP: 80% vs. 20%, LPS: 70% vs. 30%, both P<0.05).

CONCLUSION

Chronic SJ infestation could elevate anti-inflammatory factors in septic mice, thus ameliorating the survival rate, so it has protective effect on mice with sepsis.

Increased iron stores correlate with worse disease outcomes in a mouse model of schistosomiasis infection

Schistosomiasis is a significant parasitic infection creating disease burden throughout many of the world's developing nations. Iron deficiency anemia is also a significant health burden resulting from both nutritional deficit as well as parasitic infection in these countries. In this study we investigated the relationships between the disease outcomes of Schistosoma japonicum infection and iron homeostasis. We aimed to determine if host iron status has an effect on schistosome maturation or egg production, and to investigate the response of iron regulatory genes to chronic schistosomiasis infection. Wild-type C57BL/6 and Transferrin Receptor 2 null mice were infected with S. japonicum, and sacrificed at the onset of chronic disease. Transferrin Receptor 2 null mice are a model of type 3 hereditary hemochromatosis and develop significant iron overload providing increased iron stores at the onset of infection. The infectivity of schistosomes and egg production was assessed along with the subsequent development of granulomas and fibrosis. The response of the iron regulatory gene Hepcidin to infection and the changes in iron status were assessed by real-time PCR and Western blotting. Our results show that Hepcidin levels responded to the changing iron status of the animals, but were not significantly influenced by the inflammatory response. We also show that with increased iron availability at the time of infection there was greater development of fibrosis around granulomas. In conclusion, our studies indicate that chronic inflammation may not be the primary cause of the anemia seen in schistosomiasis, and suggest that increased availability of iron, such as through iron supplementation, may actually lead to increased disease severity.

[Studies on immunoprotection in mice after immunization with Schistosoma japonicum 22.6 kDa recombinant protein]

AIM

To evaluate the immunoprotective effect of Schistosoma japonicum recombinant 22.6 kDa (rSj22.6) and Sj22.6/Sj26 GST fusion protein.

METHODS

The Sj22.6/Sj26 GST fusion protein was prepared by affinity chromatography using glutathione Sepharose 4B. The purified rSj22.6 could be cleaved easily from the fusion protein with Thrombin. 17 and 12 mice immunized with rSj22.6 and Sj22.6/Sj26 GST separately were each challenged with 40 +/- 1 S. japonicum cercariae.

RESULTS

In BALB/c mice, the rSj22.6 and Sj22.6/Sj26 GST could induce 32.1 (P < 0.005) and 34.9% (P < 0.02) worm reduction, respectively, as well as 28.4% (P < 0.02) and 45.1% (P < 0.005) total egg reduction, respectively.

CONCLUSION

Bpth rSj22.6 and Sj22.6/Sj26 GST fusion protein are partially effective against S. japonicum.

Effect of anluohuaxian tablet combined with gamma-IFN on schistosomal liver fibrosis

The therapeutic effects of anluohuaxian tablet combined with gamma-IFN on schistosomal liver fibrosis and its mechanism were studied in a murine model and clinical cases of schistosomal liver fibrosis. Fifty Kunming mice were randomly divided into 5 groups: normal control group, infection control group, anluohuaxian tablet-treated group, gamma-IFN-treated group and combined treatment (anluohuaian tablet+gamma-IFN) group. Pathologic changes in liver, including hepatic pigmentation and the size of schistosomal egg granuloma, were observed by HE staining after treatment for 8 weeks. The expression of the type I and collagen III, and TIMP-1 was detected by immunohistochemistry. TGF-beta1 mRNA expression was examined by real-time fluorescent quantitative PCR. Sixty patients with schistosomal liver fibrosis were divided into treatment group and control group. The patients in treatment group were treated with anluohuaxian tablet in combination with gamma-IFN for 6 months. Before and after treatment, the changes of symptoms and signs, liver function, serum liver fibrosis indexes and imaging indexes were observed. The results showed that as compared with infection control group, all forms of treatments relieved the hepatic pathological injury with apparently diminished size of schistosomal egg nodules and decreased percentage of pigmentation (P<0.05). Furthermore, the expression of collagen I and III, TIMP-1, and TGF-beta1 mRNA in combined treatment group was significantly decreased as compared with anluohuaxian tablet-treated and gamma-IFN-treated groups (P<0.05). In the clinical observation, the serum liver fibrosis indexes, the portal vein width as well as the spleen thickness was significantly reduced in treatment group as compared with control group (P<0.05). It was concluded that the combined use of anluohuaxian tablet with gamma-IFN in schistosomal liver fibrosis could protect liver function, alleviate liver fibrosis, and could be used as a choice in treating patients with schiatosomal liver fibrosis.

[Suppressive effect of induced CD4+CD25+ regulatory T cells from mice infected with Schistosoma japonicum]

OBJECTIVE

To investigate the suppressive effect of CD4+CD25+ regulatory T cells from mice infected with Schistosoma japonicum.

METHODS

BALB/c mice were infected with S. japonicum. At 6 and 13 weeks post-infection, the spleens were removed and CD4+CD25+ T cells were separated by magnetic beads. In in vitro experiments, CD4+CD25+ T Cells were cocultured with CD4+CD25- T cells. The inhibitory role of the CD4+CD25+ T cells was assessed by [3H] thymidine incorporation method and the cytokines in the cultural supernatant were detected by ELISA. In in vivo experiments, mice inoculated with irradiated cercariae of S. japonicum were adoptively transferred with CD4+CD25+ T cells isolated from the mice chronically infected with S. japonicum. The intracellular cytokine expressions of splenocytes were performed by flow cytometry, and sera IgG1 and IgG2a antibodies against irradiated cercaria antigens were detected by ELISA.

RESULTS

In vitro, CD4+CD25+ T cells were able to suppress the proliferation of CD4+CD25- T cells when stimulated with SEA, compared with single CD4+CD25- T cells culture (cpm 7615 +/- 1 058) (P < 0.01). Furthermore, CD4+CD25+ T cells isolated from mice chronically infected with S. japonicum presented higher suppressive efficacy (cpm 2 336 +/- 490), compared with that isolated from the acutely infected mice (cmp 4 467 +/- 144) (P < 0.05). Meanwhile, CD4+CD25+ T cells isolated from mice with the acute infection inhibited the cytokine secretion by CD4+CD25- T cells and the suppression rate was 32.0% for IL-4 (P < 0.05), 66.3% for IFN-gamma (P < 0.01) and 63.2% for IL-2 (P < 0.01), respectively, and CD4+CD25+ T cells isolated from mice with the chronic infection, the suppression rate was 28.4% for IL-4 (P < 0.05), 60.1% for IFN-gamma (P < 0.01) and 58.3% for IL-2 (P < 0.01), respectively. In vivo, IFN-gamma secretion and IgG2a antibody production of mice adoptively transferred with CD4+CD25+ T cells from the chronically infected mice were suppressed when mice were inoculated with irradiated cercariae of S. japonicum (P < 0.05).

CONCLUSION

CD4+CD25+ T cells isolated from mice infected with S. japonicum have played roles of Th1-dominant immune suppression.

A contributory role for activated hepatic stellate cells in the dynamics of Schistosoma japonicum egg-induced fibrosis

The disease manifestations of schistosomiasis arise from the mammalian host-mediated type 2 T-helper cell-induced (Th2) fibro-granulomatous inflammatory response to eggs trapped within host tissues. Activated hepatic stellate cells are well described as the effector cells of hepatic fibrosis in a variety of human diseases and rodent models. The aim of this study was to further understand the mechanism of fibrosis and the role of hepatic stellate cells in hepatic schistosomiasis progression. Groups of female CBA mice, which produce an intermediate degree of Schistosoma japonicum-induced liver fibrosis, were infected with S. japonicum, perfused at fortnightly time points and the liver tissue and contained egg granulomas examined by immunohistochemistry and cytokine and chemokine analysis using quantitative PCR. Immunohistochemistry demonstrated the presence of activated hepatic stellate cells in the periphery of egg granulomas, adjacent to fibrotic areas. Time course analysis demonstrated that the transcription of smooth muscle actin-alpha type 1 collagen, IL-4, IL-13, IL-13Ralpha2 and tissue inhibitor of metalloproteinase-1 mirrored the initial increase and subsequent down-modulation of granuloma diameter in mice. However, the transcription of monocyte chemo-attractant protein-1, Regulated upon Activation Normal T Cell Expressed and Secreted (RANTES), TNF-alpha, IFN-gamma and matrix metalloproteinase-9 paralleled the evolution of the total liver disease burden. Transforming growth factor-beta1 transcription did not appear to be of biological significance in this mouse model. Immunohistochemical analysis of human hepatic granulomas showed close association of smooth muscle actin-alpha-expressing cells with fibrosis in five available cases of end-stage (advanced) schistosomiasis japonica. We conclude that activated hepatic stellate cells play a contributory role in the granulomatous, fibrotic process induced by S. japonicum eggs, both in the murine model and in human disease.

New perspectives on host-parasite interplay by comparative transcriptomic and proteomic analyses of Schistosoma japonicum

Schistosomiasis remains a serious public health problem with an estimated 200 million people infected in 76 countries. Here we isolated ~ 8,400 potential protein-encoding cDNA contigs from Schistosoma japonicum after sequencing circa 84,000 expressed sequence tags. In tandem, we undertook a high-throughput proteomics approach to characterize the protein expression profiles of a number of developmental stages (cercariae, hepatic schistosomula, female and male adults, eggs, and miracidia) and tissues at the host-parasite interface (eggshell and tegument) by interrogating the protein database deduced from the contigs. Comparative analysis of these transcriptomic and proteomic data, the latter including 3,260 proteins with putative identities, revealed differential expression of genes among the various developmental stages and sexes of S. japonicum and localization of putative secretory and membrane antigens, enzymes, and other gene products on the adult tegument and eggshell, many of which displayed genetic polymorphisms. Numerous S. japonicum genes exhibited high levels of identity with those of their mammalian hosts, whereas many others appeared to be conserved only across the genus Schistosoma or Phylum Platyhelminthes. These findings are expected to provide new insights into the pathophysiology of schistosomiasis and for the development of improved interventions for disease control and will facilitate a more fundamental understanding of schistosome biology, evolution, and the host-parasite interplay.

Schistosomiasis remains a major public health problem in the developing world. Schistosoma japonicum, the Oriental blood fluke, causes intestinal schistosomiasis in China and the Philippines. Knowledge of the genome and proteome of this worm should improve understanding of biomedical aspects of schistosomiasis. This study represents the first major attempt to characterize the majority of the expressed genes and proteins of a human blood fluke through rigorous, high-throughput genomic and proteomic methodologies. The findings of this study provide a unique resource of numerous schistosome genes and information on protein profiles of the different developmental stages of S. japonicum. Many of the newly discovered proteins are localized on the surface of the worm and its eggs, and they are likely to be involved in the pathogenesis of schistosomiasis. Furthermore, genetic variants found in many of these new genes likely reflect the ability of this important human pathogen to adapt and respond to environmental pressures and the capacity of the parasite to respond to anti-schistosomal therapies. Comparison of these S. japonicum genes with those from mammals and other organisms will facilitate advances in the understanding of blood fluke biology and evolution.

[Pigment deposit in liver of BALB/c mice infected by Schistosoma japonicum and its relation to the effect of praziquantel treatment]

Pigment is a kind of metabolite excreted by schistosome after erythrocyte ingestion. It deposited first in liver sinusoid, then outside and inside of granuloma, and around eggs. The level of pigment was in parallel with the degree of liver fibrosis (P < 0.01). After chemotherapy with praziquantel, the level of pigment decreased considerably (P < 0.01) and the size of granuloma shrinks obviously too (P < 0.01). Therefore, the degree of liver fibrosis in mice with schistosome infection and the effect of praziquantel can be recognized by the level and distribution of pigment.

Dynamic observation of liver fibrosis in mice infected with Schistosoma japonica

The expression of TNF-alpha in the liver at different periods post Schistosoma japonica infection and the effect on liver fibrosis after supplementary injection of these cytokines were investigated. The mice infected with schistosome cercariae were divided into 3 groups: normal control group, TNF-alpha-untreated infection group and TNF-alpha-treated infection group. ABC immunohistochemistry and pathologic image multimedia quantification system were applied to dynamically detect the activity of TNF-alpha. The results showed that the levels of TNF-alpha in the liver in TNF-alpha-untreated infection group were slowly decreased with prolongation of infection time (from 8th, 11th, 14th to 18th week), while in the TNF-alpha-treated infection group, those were increased significantly after intraperitoneal injection of TNF-alpha at 6th week after infection. At first to 8th week after the final injection of TNF-alpha, the intrahepatic TNF-alpha levels in the TNF-alpha-treated infection group were significantly higher than in the other two groups (P < 0.01), and the granulomatous inflammation and fibrosis in the liver were also milder in the normal control group. It was concluded that at the early stage of Schistosoma japonica infection mouse liver mainly released Th1 cytokine and TNF-alpha from Th1 activated macrophages. Six weeks after infection (post egg deposition), exogenous supplement with intraperitoneal injection of TNF-alpha could induce the enhanced expression of Th1 cytokines and alleviate the liver granulomatous inflammation and fibrosis.

[Expression of hepatic Bcl-2 and Bax proteins in schistosome-infected mice and the role of pentoxifylline]

OBJECTIVE

To study the expression of hepatic Bcl-2 and Bax proteins in mice infected with Schistosoma japonicum and the role of pentoxifylline (PTX) in the expression.

METHODS

Forty mice were randomly divided into 4 groups: one normal control group,mice in the other three groups were all infected each with 25 cercariae, the infected control group was fed for 10 weeks after infection, and 2 weeks after infection, the high dose PTX group was given PTX 360 mg/(kg x d) for 8 weeks and the low dose PTX group was given PTX 180 mg/(kg x d)also for 8 weeks. At the end of 10 weeks all the mice were killed. Bcl-2 and Bax proteins expression was detected by immunohistochemisty.

RESULTS

Compared with the normal control group, the expression of Bcl-2 and Bax was significantly higher in the infected control group (P < 0.05). Bcl-2 was significantly higher in high (dose PTX group than in the infected control group and in low dose PTX group (P < 0.05). However there was no significant difference in the expression of Bax among the groups (P > 0.05).

CONCLUSION

PTX treatment can significantly increase the expression of Bcl-2 in liver tissue of schistosome-infected mice in a dose-dependent manner, and may play a role against liver inflammation and schistosomiasis-related liver fibrosis.

System level metabolic effects of a Schistosoma japonicum infection in the Syrian hamster

A metabolic profiling strategy was used to investigate the metabolic responses of Syrian hamsters (SLAC) to a Schistosoma japonicum infection using high resolution 1H nuclear magnetic resonance (NMR) spectroscopy and pattern recognition. In two independent experiments, male hamsters were each infected with 100 S. japonicum cercariae. At days 34-36 post-infection, urine was obtained from hamsters housed individually in metabolism cages. At the same time, urine was collected from age- and sex-matched infection-free control hamsters. The main biochemical effects of a S. japonicum infection in the hamster consisted of reduced levels of urinary tricarboxylic acid cycle intermediates, including citrate and succinate and increased levels of pyruvate. In addition, a range of microbial-related metabolites, such as hippurate, p-cresol glucuronide, phenylacetylglycine and trimethylamine were also associated with a S. japonicum infection. Most of the observed biochemical effects were in common with those previously characterized for a S. mansoni infection in a mouse host. The major distinguishing consequence of a S. japonicum infection in the hamster was the inhibition of manufacture or utilization of short-chain fatty acids, when compared to a S. mansoni infection in the mouse.

[Influence of interferon gamma treatment on expression of TGF-beta1 and its receptors in liver fibrosis of mice with schistosomiasis japonica]

OBJECTIVE

To investigate the effect of interferon-gamma (IFN-gamma) on the expression of TGF-beta1 and its two membrane receptors--TGF-beta receptor I (TbetaRI), TGF-beta receptor II (TbetaRII), and observe the expression of TGF-beta1, TbetaRI and TbetaRII during the development of liver fibrosis in BALB/c mice infected by Schistosoma japonicum.

METHODS

BALB/c mice, aged 6-8 weeks, were infected with cercariae of S. japonicum. The infected mice were divided randomly into three groups 16 week after infection: model group, praziquantel group and praziquantel combined with IFN-gamma group. Liver specimen were obtained at 8, 12, 16 week and at the end of treatment. Pathological examination, immunohistochemistry and RT-PCR were used to evaluate the pathological change, the expression of TGF-beta1, TbetaRI and TbetaRII and the mRNA level respectively.

RESULTS

The expression of TGF-beta1, TbetaRI, and TbetaRII can be detected in infected mice, while the expression around egg granulomas enhanced along with the progress of the disease. With the therapy of IFN-gamma, the reduction of egg granulomas, and of the expression of TGF-beta1, TbetaRI and TbetaRII was observed. From the transcription level, it was found that TGF-beta1 mRNA increased at 12 week and peaked at model group, then decreased to the normal level after treatment with IFN-gamma combined with praziquantel. The level of TbetaRII mRNA reduced at 8 and 16 week and returned to normal at the end of treatment. More interestingly, TbetaRI mRNA remained at the normal level on the whole course both in the development of fibrogenesis and the period of treatment.

CONCLUSION

The up regulation of TGF-beta1 and down regulation of TbetaRII mRNA may induce liver fibrogenesis and IFN-gamma might suppress TGF-beta1 to reverse fibrosis. The mechanism of the suppression is mediated by down regulation of expression of its two receptors at protein level but not by influencing the mRNA expression.

[Studies on Smads at transcription level in liver fibrosis of mice with Schistosomiasis japonica]

OBJECTIVE

To study Smads involved in TGF-beta signal transduction at the transcription level during the development of liver fibrosis in BALB/c mice infected by Schistosoma japonicum.

METHODS

BALB/c mice infected with cercariae of S. japonicum were used as liver fibrosis models. Liver specimens were harvested at 8, 12, 16 and 24 weeks after infection and normal control were sacrificed at the 24th week. A part of the liver specimens were preserved for pathologic examination and the other part was frozen for the detection of mRNA level of Smad 2, Smad 3, Smad 4 and Smad 7.

RESULTS

The level of Smad 3 mRNA was significantly higher than that of control at the later stage, while the mRNA level of Smad 2 decreased at 12 and at 24 weeks, respectively. No significant difference in the mRNA level of Smad 4 and Smad 7 was observed between the infection group and the control.

CONCLUSION

Smad 3 may induce the development of liver fibrosis in mice infected by S. japonicum while Smad 2 may induce the development of liver fibrosis at early stage and inhibit it at later stage.

[Studies on the characteristic of interferon-gamma mediating resistance in mice infected with Schistosoma japonicum]

OBJECTIVE

To investigate the molecular characteristic of interferon-gamma mediating protective immunity against schistosomiasis japonica in mice.

METHODS

CD4+ T cells were isolated from spleens of mice infected with Schistosoma japonicum at different time-points. The cDNA microarray technique combined with RT-PCR was used to explore IFN-gamma inducible GTPase family gene expression profile of CD4+ T cell. IGTP, a representative IFN-gamma, inducible GTPase having vital anti-infection activity, was amplified from spleen of BALB/c mice using RT-PCR, then cloned into pGEM(r)-T easy vector for sequencing.

RESULTS

IFN-gamma inducible GTPase family had the similar characteristic over the course of S. japonicum infection. The gene expression of these members were up-regulated or had little change at 3 wk post-infection, then down-modulated from 6 wk to 13 wk post-infection, which was also confirmed by RT-PCR. As for IGTP, two inserts were identified after sequencing. One was 142 bp shorter than another, but the fragment was lost due to low annealing temperature.

CONCLUSION

There is a dramatic inhibition of IFN-gamma pathway and IFN-gamma-dependent anti-infective immunity during the infection of S. japonicum.

[Effect of pentoxifylline on the expression of hepatic TGF-beta 1, type I and type III collagen in mice with liver fibrosis due to Schistosoma japonicum infection]

OBJECTIVE

To study the effect of pentoxifylline (PTX) on the content of hepatic TGF-beta 1, type I and type III collagen in schistosome-infected mice with liver fibrosis.

METHODS

Forty mice with schistosomiasis were divided into four groups: one group as control without any treatment, other three were treated with praziquantel 500 mg/(kg.d) for 2 d, high dose PTX 360 mg/(kg.d) for 8 wk, and low dose PTX 180 mg/(kg.d) for 8 wk respectively. Immunohistochemical technique and multimedia color pathographic analysis system were applied to observe the content of hepatic TGF-beta 1, type I and type III collagen in mice infected with S. japonicum before and after treatment.

RESULTS

The effect of PTX on the content of hepatic TGF-beta 1, type I and type III collagen in mice was related to the dosage of PTX. High dose PTX treatment significantly reduced the content of TGF-beta 1, type I and type III collagen compared to the control (P < 0.01), whereas no difference was found between the group of low dose PTX treatment and control (P > 0.05).

CONCLUSION

High dose PTX treatment could reduce the content of hepatic TGF-beta 1, type I and type III collagen significantly in schistosome-infected mice with liver fibrosis.

[Studies on synthesis and degradation of collagen at transcription level in liver fibrosis of rabbits with schistosomiasis japonica]

OBJECTIVE

To study the synthesis and degradation of collagen at the transcription level during liver fibrosis in rabbits with schistosomiasis japonica.

METHODS

New Zealand rabbits infected with Schistosoma japonicum cercariae were served as animal models of liver fibrosis. The liver specimens were collected through operations at 4, 6, 8, 10, 12, 16, 20, 24 and 28 weeks after infection. Type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels of liver tissue were detected by RT-PCR plus dot blotting, and the size of egg granulomas and the degree of liver fibrosis were measured by histopathological examinations.

RESULTS

Type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels increased simultaneously in the early stage after the infection, mostly reaching their peaks at 10 weeks after infection. Compared with normal controls, type I collagen, type III collagen, type IV collagen, MMP-1 and MMP-9 mRNA levels increased by 12.0-, 11.0-, 6.6-, 10.0- and 11.0-fold, respectively, coinciding with the changes of egg granulomas. Thereafter, both collagen and collagenase mRNA levels decreased. Types I, III and IV collagen mRNA levels declined to 2-fold to 3-fold compared with normal controls (P < 0.05), while MMP-1 and MMP-9 mRNA levels declined to normal level (P > 0.05) at 28 weeks. This study showed that the synthesis and degradation of collagen remained dynamic balance in the early stage of schistosomiasis, while in the later stage the metabolism of collagen synthesis was higher than that of collagen degradation.

CONCLUSION

It was confirmed at the transcription level that when the metabolism of collagen synthesis was higher than that of collagen degradation in rabbits with schistosomiasis japonica, liver fibrosis might be produced.

[Dynamic changes in collagen type I and collagen type III in rabbits infected with Schistosoma japonicum and the effect of gamma-interferon]

OBJECTIVE

To observe the dynamic changes in collagen type I and collagen type III in rabbits with schistosomiasis japonica and the treatment effect of gamma-interferon on the degradation of collagens in schistosomal hepatic fibrosis.

METHODS

Each rabbit was infected with 80 +/- 1 S. japonicum cercariae. Liver operations were done at different time points after infection and the liver specimens were embedded with paraffin and stained with alpha-SMA, HE and picric acid-Sirius red. The stained slides were observed under polarizing microscope and different collagen areas calculated by computer imagine analysis system. At the 16th week after infection, the infected rabbits received a single dose of praziquantel and gamma-interferon for 8 weeks.

RESULTS

The area percent of collagen type I at the 28th week after infection (40.14 +/- 17.00) increased about seven fold compared with the 8th week group (5.73 +/- 3.40). The area percent of collagen type III at the 28th week after infection (6.80 +/- 5.19) increased about six fold compared with the 8th week group (1.15 +/- 1.34). The alpha-SMA positive cells also increased significantly. After gamma-interferon treatment, the area percent of collagen type I and type III decreased significantly, from 18.51 +/- 7.52 and 4.63 +/- 3.64 (before treatment) to 3.09 +/- 1.54 and 0.40 +/- 0.37 (0 and 4 weeks after treatment) (P < 0.01). However, after the withdrawl of gamma-interferon treatment, the collagen degradation was reversible.

CONCLUSION

Gamma-interferon is effective in the treatment of hepatic fibrosis in rabbits infected with S. japonicum, the effect being reversible.

Study on IL-4, IL-5 and IL-10 in liver and bone marrow of mice infected with Schistosomiasis Japonica

To compare Th2 cytokines levels in livers and bone marrow of mice infected with Schistosomiasis Japonica and understand their implication, ABC immunohistochemical staining technique and multimedia pathologic pictures analysis were used to detect the IL-4, IL-5 and IL-10 derived from livers and bone marrow of infected mice. Results showed that in the livers of infected mice, IL-4, IL-5 and IL-10 were obviously increased over time. The level of IL-4 was increased most among the 3 indicators. In bone marrow of infected mice, however, even though IL-4 was slowly increased over time, it was lower than that of livers in 10th and 12th week. The level of IL-5 was higher than that of livers during 12th weeks. Before 10th weeks IL-10 was elevated. After 12th week IL-10 was decreased and obviously lower than that of livers. It is concluded that in mice infected with Schistosomiasis Japonica, the immune response occurred mainly in the liver. Therefore, in bone marrow, IL-5 showed obvious auto-secretion. It might be related to its biological ability to induce B cell division and eosinophil differentiation.

[Effects of IFN-gamma gene-modified hepatocytes on TGF-beta 1 and its receptor in mice infected with Schistosoma japonicum]

AIM

To explore the anti-schistosomal hepatic fibrosis effect and the changes in transforming growth factor-beta 1 (TGF-beta 1) and its receptors (TGF-beta RII) in S. japonicum infected mice after intrasplenic transplantation of gamma-interferon (IFN-gamma) gene-modified hepatocytes.

METHODS

At 16 wk after infection with cercariae of Schistosoma japonicum, the mice were intrasplenically transplantated with murine hepatocytes which had been transfected with IFN-gamma gene-combinant adenovirus vector. ELISA, immunohistochemical and dot blot techniques were used to observe the dynamic changes in IFN-gamma, TGF-beta 1, TGF-beta RII and type I, III collagen.

RESULTS

The intrasplenic transplantation of IFN-gamma gene modified hepatocytes effectively expressed IFN-gamma and obviously reduced the production and deposition of type I, III collagen as well as TGF-beta 1 and TGF-beta RII.

CONCLUSION

IFN-gamma gene transplantation has anti-hepatic fibrosis efficacy in Schistosoma japonicum-infected mice, being related to its role of decreasing the expression of TGF-beta 1 and TGF-beta RII.

[Dynamic changes in IL-4, IL-5 and IL-10 in liver and bone marrow of mice infected with Schistosoma japonicum]

AIM

To observe the changes in Th2 cytokines in the liver and bone marrow of mice infected with schistosomiasis japonica.

METHODS

ABC immunohistochemical staining technique and multimedia pathological picture analysis were used. Meanwhile, IL-4, IL-5 and IL-10 derived from livers and bone marrows of infected mice were observed at wk 8, 10 and 12 after infection.

RESULTS AND CONCLUSION

In the livers of infected mice, the levels of IL-4, IL-5 and IL-10 increased obviously with a prolongation of the infection duration, IL-4 being the highest. However, in the bone marrow of infected mice, IL-4 level increased slowly with the duration of the infection, being lower than those in the liver at wk 10 and 12 after infection. The level of IL-5 was higher than that in the liver within 12 wk. At wk 10 after infection IL-10 tended to increase, but decreased thereafter and was obviously lower than that in the liver. In mice infected with Schistosoma japonicum, the immune response occurred mainly in the liver. IL-5 in the bone marrow showed auto-secretion.

Effects of pentoxifylline on the hepatic content of TGF-β1 and collagen in Schistosomiasis japonica mice with liver fibrosis

AIM: To study the effects of pentoxifylline (PTX) on the content of hepatic TGF-β1, type I and type III collagen in schistosomiasis japonica mice with liver fibrosis and its mechanism of anti-fibrosis.

METHODS: Forty mice with schistosomiasis were divided into four groups: one group as control without any treatment, other three were treated with Praziquantel 500 mg/(kg·d)for 2 d, high dose PTX 360 mg/(kg·d) for 8 wk, and low dose PTX 180 mg/(kg·d) for 8 wk respectively. Immunohistochemical technique and multimedia color pathographic analysis system were applied to observe the content change of hepatic TGF-β1, type I and type III collagen in schistosomiasis japonica mice with liver fibrosis before and after PTX treatment.

RESULTS: Effects of PTX on the content change of hepatic TGF-β1, type I and type III collagen in schistosomiasis japonica mice with liver fibrosis were related to the dosage of PTX, high dose PTX treated group could significantly reduce the content of TGF-β1 (0.709 ± 0.111), type I (0.644 ± 0.108) and type III (0.654 ± 0.152) collagen compared with those of control group (0.883 ± 0.140, 0.771 ± 0.156, 0.822 ± 0.129) with statistical significance (P < 0.05). Low dose PTX could also reduce the hepatic content of TGF-β1 (0.752 ± 0.152), type I (0.733 ± 0.117) and type III (0.788 ± 0.147) collagen, but without statistical significance (P > 0.05). Both high dose and low dose PTX groups have significant differences on the content of TGF-β1, type I and type III collagen (P < 0.05, P < 0.05, P < 0.01, respectively).

CONCLUSION: High dose of PTX treatment could reduce the content of hepatic TGF-β1, type I and type III collagen significantly in schistosomiasis japonica mice with liver fibrosis, and thus plays its role of antifibrosis.

[Expression of matrix metalloproteinase 2 and 9 in liver tissue of patients with schistosomiasis japonica]

OBJECTIVE

To explore the change of matrix metalloproteinase-2(MMP-2) and matrix metalloproteinase-9 (MMP-9) expression in liver tissue of the patients with schistosomiasis japonica.

METHODS

Liver biopsy materials were examined pathomorphologically in 26 patients with schistosomiasis in advanced stage and 5 cases without the disease as control. The expression of MMP-2, MMP-9 and C-IV were studied by immunohistochemistry, and result was analyzed by picture quantitative analysis technique.

RESULTS

Immnoreactive MMP-2 was mainly expressed in the plasma, the membrane of hepatocytes and hepatic sinusoids, it was also found in myofibroblast cells and endothelial cells of blood vessel. Immnoreactive MMP-9 was observed in hepatic stellate cells, sinusoids and myofibroblast cells, sometimes it was also seen in the plasma of hepatocytes and epithelial cells of bile duct. The expression of MMP-2, MMP-9 and C-IV was significantly stronger in patients with advanced schistosomiasis than that of the control(P < 0.05). The expression of MMP-2 was relevant to the inflammation grade and stage of liver fibrosis(P < 0.01). The expression of MMP-9 did not show significant change(P > 0.05) and the expression of C-IV was consistent with that of MMP-2.

CONCLUSION

The study indicates that increased expression of MMP-2 participated in the initiation and development process of liver fibrosis, MMP-9 was related to the initiation of liver fibrosis and pathological change existed in hepatic sinusoids in advanced schistosomiasis japonica.