Schistosoma japonicum protein SjP40 inhibits TGF-β1-induced activation of hepatic stellate cells

ATF3 is involved in rSjP40-mediated inhibition of HSCs activation in Schistosoma japonicum-infected mice

Schistosomiasis is a parasitic disease characterized by liver fibrosis, a process driven by the activation of hepatic stellate cells (HSCs) and subsequent collagen production. Previous studies from our laboratory have demonstrated the ability of Schistosoma japonicum protein P40 (SjP40) to inhibit HSCs activation and exert an antifibrotic effect. In this study, we aimed to elucidate the molecular mechanism underlying the inhibitory effect of recombinant SjP40 (rSjP40) on HSCs activation. Using a cell model in which rSjP40 inhibited LX-2 cell activation, we performed RNA-seq analyses and identified ATF3 as the most significantly altered gene. Further investigation revealed that rSjP40 inhibited HSCs activation partly by suppressing ATF3 activation. Knockdown of ATF3 in mouse liver significantly alleviated S. japonicum-induced liver fibrosis. Moreover, our results indicate that ATF3 is a direct target of microRNA-494-3p, a microRNA associated with anti-liver fibrosis effects. rSjP40 was found to downregulate ATF3 expression by upregulating microRNA-494-3p in LX-2 cells. This downregulation led to the inhibition of the expression of liver fibrosis proteins α-SMA and COL1A1, ultimately alleviating liver fibrosis caused by S. japonicum.

Multifunctional Roles of MicroRNAs in Schistosomiasis

Schistosomiasis is a parasitic disease that is caused by helminths of the genus Schistosoma. The dioecious schistosomes mate and lay eggs after undergoing a complex life cycle. Schistosome eggs are mostly responsible for the transmission of schistosomiasis and chronic fibrotic disease induced by egg antigens is the main cause of the high mortality rate. Currently, chemotherapy with praziquantel (PZQ) is the only effective treatment against schistosomiasis, although the potential of drug resistance remains a concern. Hence, there is an urgent demand for new and effective strategies to combat schistosomiasis, which is the second most prevalent parasitic disease after malaria. MicroRNAs (miRNAs) are small non-coding RNAs that play pivotal regulatory roles in many organisms, including the development and sexual maturation of schistosomes. Thus, miRNAs are potential targets for treatment of schistosomiasis. Moreover, miRNAs can serve as multifunctional “nano-tools” for cross-species delivery in order to regulate host-parasite interactions. In this review, the multifunctional roles of miRNAs in the growth and development of schistosomes are discussed. The various regulatory functions of host-derived and worm-derived miRNAs on the progression of schistosomiasis are also thoroughly addressed, especially the promotional and inhibitory effects on schistosome-induced liver fibrosis. Additionally, the potential of miRNAs as biomarkers for the diagnosis and treatment of schistosomiasis is considered.

Recombinant P40 protein of Schistosoma japonicum inhibits TREM-1 expression in RAW264.7 cells via FOXO3a

Triggering receptor expressed on myeloid cells 1 (TREM-1) is a transmembrane glycoprotein receptor and TREM-1 expression reached the peak at 6 weeks after infection with Schistosoma japonicum and inhibited subsequently. Since TREM-1 may be involved in the macrophage polarization process, the reason for the inhibition of TREM-1 expression in chronic schistosomiasis engaged us in them. In this study, flow cytometry was used to observe TREM-1 expression in peritoneal macrophages from mice infected with Schistosoma japonicum. Since P40 is one of the main components from schistosoma eggs, western blot and dual-luciferase reporter assays were performed to observe the effect of recombinant Schistosoma japonicum P40 protein (rSjP40) on TREM-1 expression in the mouse leukemic monocyte/macrophage cell line RAW264.7. These methods were also conducted to observe the effect of FOXO3a on the expression of TREM-1 in RAW264.7 cells, and a ChIP assay was performed to confirm the binding site of FOXO3a to the TREM-1 promoter. Our results showed that TREM-1 expression reached the peak in peritoneal macrophages from mice at 6 weeks after infection with Schistosoma japonicum. rSjP40 inhibited TREM-1 promoter activity at the position of - 1924 ~ - 1531 bp. rSjP40 down-regulated TREM-1 and FOXO3a protein expression in RAW264.7 cells. TREM-1 protein expression may be regulated by binding of FOXO3a to the promoter of TREM-1 in RAW264.7 cells. In conclusion, we found that rSjP40 inhibited TREM-1 expression in macrophages by inhibiting FOXO3a expression. This study will provide the basis for the study to explore the role of TREM-1 in Schistosoma japonicum infection.

rSjP40 Inhibited the Activity of Collagen Type I Promoter via Ets-1 in HSCs

Liver fibrosis is a severe disease characterized by excessive deposition of extracellular matrix (ECM) components in the liver. Activated hepatic stellate cells (HSCs) are a major source of ECM and a key regulator of liver fibrosis. Collagen type I alpha I (COL1A1) is one of the main components of ECM and is a major component in fibrotic tissues. Previously, we demonstrated that soluble egg antigen from Schistosoma japonicum could inhibit the expression of COL1A1 in activated HSCs. In addition, studies have found that Ets proto-oncogene 1 (Ets-1) suppresses the production of ECM by down-regulating matrix related genes such as COL1A1 induced by transforming growth factor β, and ultimately inhibits liver fibrosis. In this study, the major aim was to investigate the effect and mechanism of Ets-1 on inhibiting COL1A1 gene promoter activity in HSCs by recombinant Schistosoma japonicum protein P40 (rSjP40). We observed the rSjP40 inhibited the expression of COL1A1 by inhibiting the activity of the COL1A1 promoter, and the core region of rSjP40 acting on COL1A1 promoter was located at -1,722/-1,592. In addition, we also demonstrated that rSjP40 could promote the expression of Ets-1, and Ets-1 has a negative regulation effect on the COL1A1 promoter in human LX-2 cells. These data suggest that rSjP40 might inhibit the activity of COL1A1 promoter and inhibit the activation of HSCs by increasing the expression of transcription factor Ets-1, which will provide a new experimental basis for the prevention and treatment of liver fibrosis.

Involvement of SIRT1 in amelioration of schistosomiasis-induced hepatic fibrosis by genistein

Previous study revealed that genistein alleviate the extent of hepatic fibrosis in schistosomiasis-infected mice, however, the potential mechanism is still incomplete. Present study was, therefore, carried out to investigate the underlying mechanism of ameliorating schistosomiasis-induced hepatic fibrosis by genistein. α-smooth muscle actin (α-SMA) expression, as a critical fibrotic marker, was markedly upregulated in Schistosoma japonicum (S. japonicum) egg-induced liver fibrosis, and gradually inhibited by genistein administration in infected mice. Contrary to the changes of α-SMA expression, hepatic SIRT1 expression and activity was greatly inhibited in mice upon S. japonicum infection, and the repression was reversed in liver tissues after receiving 25 mg/kg genistein. 50 mg/kg genistein treatment gave rise to the higher SIRT1 expression and activity than that of the control group. In hepatic stellate cells (HSCs), genistein (5, 10, 20 μM) treatment resulted in the increases of SIRT1 expression and activity in concentration-dependent manner. Moreover, to mimic the fibrogenesis in vivo, macrophage was treated with soluble egg antigen (SEA) to obtain macrophage-conditioned medium (MφCM), which was used to stimulate HSCs. Intriguingly, SIRT1 overexpression decreased fibrosis associated gene expression in HSCs exposed to MφCM or not. Additionally, MφCM gave rise to high levels of α-SMA and p-Smad3 and the increments were reversed upon genistein treatment in HSCs. Furthermore, EX527, SIRT1 specific inhibitor, abrogated the inhibitory effects of genistein on HSCs activation. Together, the results support the notion that the strong elevation of SIRT1 expression and activity may represent a potential mechanism of protection against schistosomiasis-induced hepatic fibrosis by genistein.

Modulation of the Host Immune Response by Schistosome Egg-Secreted Proteins Is a Critical Avenue of Host-Parasite Communication

During a schistosome infection, the interactions that occur between the mammalian host and the parasite change rapidly once egg laying begins. Both juvenile and adult schistosomes adapt to indefinitely avoid the host immune system. In contrast, the survival of eggs relies on quickly traversing from the host. Following the commencement of egg laying, the host immune response undergoes a shift from a type 1 helper (Th1) inflammatory response to a type 2 helper (Th2) granulomatous response. This change is driven by immunomodulatory proteins within the egg excretory/secretory products (ESPs), which interact with host cells and alter their behaviour to promote egg translocation. However, in parallel, these ESPs also provoke the development of chronic schistosomiasis pathology. Recent studies using high-throughput proteomics have begun to characterise the components of schistosome egg ESPs, particularly those of Schistosoma mansoni, S. japonicum and S. haematobium. Future application of this knowledge may lead to the identification of proteins with novel immunomodulatory activity or pathological importance. However, efforts in this area are limited by a lack of in situ or in vivo functional characterisation of these proteins. This review will highlight the current knowledge of the content and demonstrated functions of schistosome egg ESPs.

The role of let-7b in the inhibition of hepatic stellate cell activation by rSjP40

BACKGROUND

Hepatic stellate cells (HSCs) are one of the main cell types involved in liver fibrosis induced by many factors, including schistosomes. Previous studies in our lab have shown that recombinant P40 protein from Schistosoma japonicum (rSjP40) can inhibit HSC activation in vitro. Let-7b is a member of the let-7 microRNA family and plays an inhibitory role in a variety of diseases and inflammatory conditions. In this study, we investigated the role of let-7b in the inhibition of HSC activation by rSjP40.

METHODS

Expression of let-7b was detected by quantitative real-time PCR. A dual luciferase assay was used to confirm direct interaction between let-7b and collagen I. We also used western blot to assess protein levels of TGFβRI and collagen type I α1 (COL1A1).

RESULTS

We found that rSjP40 up-regulates expression of let-7b in HSCs. Let-7b inhibits collagen I expression by directly targeting the 3'UTR region of the collagen I gene. Furthermore, we discovered that let-7b inhibitor partially restores the loss of collagen I expression caused by rSjP40.

CONCLUSION

Our research clarifies the role of let-7b in the inhibition of HSC activation by rSjP40 and will provide new insights and ideas for the inhibition of HSC activation and treatment of liver fibrosis.

Expression of recombinant Schistosoma japonicum protein rSjE16 and its effects on LX-2 cells in vitro

Objective

The activation of hepatic stellate cells (HSCs) is a key event in schistosome-induced liver fibrosis. Previous studies have shown that soluble egg antigens and the recombinant P40 protein from Schistosoma japonicum eggs inhibit HSC activation. In the present study, we observed the direct effect of the S. japonicum recombinant (r)SjE16 protein on HSCs.

Methods

The sequence of SjE16 was analyzed by bioinformatics. Then western blotting, quantitative PCR, and MTT assays were performed to observe the effects of rSjE16 on HSCs.

Results

The SjE16 protein has no signal peptide or transmembrane region. rSjE16 significantly inhibited expression levels of α-smooth muscle actin and collagen I protein in LX-2 cells. rSjE16 also significantly increased the expression levels of interleukin (IL)-6 and IL-8, and enhanced the expression of matrix metalloproteinase (MMP)-2, MMP-9, and peroxisome proliferator-activated receptor-γ in LX-2 cells. LX-2 cell viability was not inhibited by rSjE16.

Conclusion

rSjE16 may be involved in the progression of HSC activation via a complex molecular mechanism, which requires further study to fully understand.

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

Background: The host-parasite relationship is based on subtle interplay between parasite survival strategies and host defense mechanisms. It is well known that helminth infection, which afflicts more than one billion people globally, correlates with a decreased prevalence of obesity. Dissecting the underlying mechanisms can provide new targets for treating obesity from the host-parasite interaction perspective.

Methods: C57BL/6 mice received a normal or high-fat diet (HFD) with or without Sjp40 (one main component of schistosome-derived soluble egg antigens) treatment. Both the loss and gain-of-function experiments by the inhibitor suppression and lentivirus treatment of miR-802 were utilized to elucidate the role of miR-802/AMPK axis in host lipid metabolism. Hepatocyte lipogenesis assay and metabolic parameters were assessed both in vivo and in vitro. The potential interactions among Sjp40, CD36, miR-802, Prkab1, and AMPK were clarified by pull-down, miRNA expression microarray, quantitative RT-PCR, dual-luciferase reporter assay, and western blotting analysis.

Results: We showed a link between decreased miR-802 and impaired lipid metabolism in Schistosoma japonicum infected mice. The decreased miR-802 promotes murine Prkab1 or human Prkaa1 expression, respectively, which increases levels of phosphorylated AMPK, resulting in a decrease in hepatic lipogenesis. Also, injection with schistosome-derived soluble egg antigens (SEA) attenuated metabolism. We demonstrated that Sjp40 as a main component of SEA interacted with CD36 on hepatocytes to inhibit miR-802, resulting in the activation of AMPK pathway and subsequent attenuation of lipogenesis.

Collectively: Our study reveals the significant role of miR-802/AMPK axis in hepatic lipid metabolism and identifies the therapeutic potential of Sjp40 in treating obesity-related fatty liver.

A comparative proteomics analysis of the egg secretions of three major schistosome species

Morbidity associated with hepatic and urogenital schistosomiasis stems primarily from the host immune response directed against schistosome eggs. When eggs become entrapped in host tissues, the development of fibrotic plaques drives downstream pathology. These events occur due to the antigenic nature of egg excretory/secretory products (ESPs). Both Schistosoma mansoni and S. japonicum ESPs have been shown to interact with several cell populations in the host liver including hepatocytes, macrophages, and hepatic stellate cells, with both immunomodulatory and pathological consequences. Several protein components of the ESPs of S. mansoni and S. japonicum eggs have been characterised; however, studies into the collective contents of schistosome egg ESPs are lacking. Utilising shotgun mass spectrometry and an array of in silico analyses, we identified 266, 90 and 50 proteins within the S. mansoni, S. japonicum and S. haematobium egg secretomes respectively. We identified numerous proteins with already established immunomodulatory activities, vaccine candidates and vesicle markers. Relatively few common orthologues within the ESPs were identified by BLAST, indicating that the three egg secretomes differ in content significantly. Having a clearer understanding of these components may lead to the identification of new proteins with uncharacterised immunomodulatory potential or pathological relevance. This will enhance our understanding of host-parasite interactions, particularly those occurring during chronic schistosomiasis, and pave the way towards novel therapeutics and vaccines.

A Biological and Immunological Characterization of Schistosoma Japonicum Heat Shock Proteins 40 and 90α

We characterized Schistosoma japonicum HSP40 (Sjp40) and HSP90α (Sjp90α) in this study. Western blot analysis revealed both are present in soluble egg antigens and egg secretory proteins, implicating them in triggering the host immune response after secretion from eggs into host tissues. These observations were confirmed by immunolocalization showing both HSPs are located in the Reynolds’ layer within mature eggs, suggesting they are secreted by miracidia and accumulate between the envelope and the eggshell. Both HSPs are present in the musculature and parenchyma of adult males and in the vitelline cells of females; only Sjp90α is present on the tegument of adults. Sjp40 was able to enhance the expression of macrophages, dendritic cells, and eosinophilic cells in mouse liver non-parenchymal cells, whereas rSjp90α only stimulated the expression of dendritic cells. T helper 1 (Th1), Th2, and Th17 responses were increased upon rSjp40 stimulation in vitro, but rSjp90 only stimulated an increased Th17 response. Sjp40 has an important role in reducing the expression of fibrogenic gene markers in hepatic stellate cells in vitro. Overall, these findings provide new information on HSPs in S. japonicum, improving our understanding of the pathological roles they play in their interaction with host immune cells.

Taurine Alleviates Schistosoma-Induced Liver Injury by Inhibiting the TXNIP/NLRP3 Inflammasome Signal Pathway and Pyroptosis

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

rSjp40 inhibits activated hepatic stellate cells by promoting nuclear translocation of YB1 and inducing BMP-7/Smad1/5/8 pathway

Background

Activation of hepatic stellate cells is the dominant pathogenic event during the process of liver fibrosis. Bone morphogenic protein (BMP)-7 has recently been identified as an anti-fibrotic factor and leads to phosphorylation of Smad1/5/8 in activated hepatic stellate cells. Its expression can be upregulated by the transcriptional activator, Y-Box protein-1 (YB1). Previous studies have found that the recombinant Schistosoma japonicum protein p40 (rSjp40) can inhibit the activation of hepatic stellate cells, and based on this evidence we attempted to investigate whether or not BMP-7 is involved in rSjp40’s inhibition.

Methods

A human hepatic stellate cell line, the LX-2 cell line, was cultured and treated with rSjp40. The role of BMP-7 was analyzed by Western blot.

Results

Our findings testified that knockdown of BMP-7 impaired rSjp40-induced downregulation of α-SMA and phosphorylation of Smad1/5/8 in LX-2 cells. Furthermore, rSjp40 upregulated expression of BMP-7 at both mRNA and protein levels depending on YB1. Interestingly, YB1 was translocated from the cytoplasm to the nucleus upon treatment of rSjp40.

Conclusions

These results suggest that rSjp40 inhibits the activation of hepatic stellate cells by promoting nuclear translocation of YB1 and inducing BMP-7/Smad1/5/8 pathway, which provide a new clue to guide ongoing research into the anti-fibrosis of rSjp40.

rSJYB1 inhibits collagen type I protein expression in hepatic stellate cells via down-regulating activity of collagen α1 (I) promoter

YB1 is a negative regulator in liver fibrosis. We wondered whether SJYB1, a homologous protein of YB1 from Schistosoma japonicum, has an effect on liver fibrosis in vitro. Recombinant SJYB1 (rSJYB1) protein was expressed in a bacterial system and purified by Ni‐NTA His·Bind Resin. A human hepatic stellate cell line, the LX‐2 cell line, was cultured and treated with rSJYB1. The role of rSJYB1 on LX‐2 cells was then analysed by Western blot and luciferase assay. We succeeded in expressing and purifying SJYB1 in a bacterial system and the purified rSJYB1 could be recognized by S japonicum‐infected rabbit sera. Western bolt analysis showed that rSJYB1 inhibited the expression of collagen type I, but had little effect on α‐smooth muscle actin (α‐SMA). Further analysis revealed that rSJYB1 inhibited the activity of collagen α1 (I) (COL1A1) promoter and functioned at −1592/−1176 region of COL1A1 promoter. Our data demonstrate that rSJYB1‐mediated anti‐fibrotic activity involves inhibiting the activity of COL1A1 promoter and subsequently suppressing the expression of collagen type I in hepatic stellate cells.

rSjP40 suppresses hepatic stellate cell activation by promoting microRNA-155 expression and inhibiting STAT5 and FOXO3a expression

Activation of hepatic stellate cells (HSCs) is the central event of the evolution of hepatic fibrosis. Schistosomiasis is one of the pathogenic factors which could induce hepatic fibrosis. Previous studies have shown that recombinant Schistosoma japonicum egg antigen P40 (rSjP40) can inhibit the activation and proliferation of HSCs. MicroRNA‐155 is one of the multifunctional noncoding RNA, which is involved in a series of important biological processes including cell development, proliferation, differentiation and apoptosis. Here, we try to observe the role of microRNA‐155 in rSjP40‐inhibited HSC activation and explore its potential mechanisms. We found that microRNA‐155 was raised in rSjP40‐treated HSCs, and further studies have shown that rSjP40 enhanced microRNA‐155 expression by inhibiting STAT5 transcription. Up‐regulated microRNA‐155 can down‐regulate the expression of FOXO3a and then participate in rSjP40‐inhibited expression of α‐smooth muscle actin (α‐SMA) and collagen I. Furthermore, we observed microRNA‐155 inhibitor could partially restore the down‐regulation of FOXO3a, α‐SMA and collagen I expression in LX‐2 cells induced by rSjP40. Therefore, our research provides further insight into the mechanism by which rSjP40 could inhibit HSC activation via miR‐155.

microRNA-146a is involved in rSjP40-inhibited activation of LX-2 cells by targeting Smad4 expression

Previous studies have demonstrated that the recombinant Schistosoma japonicum protein P40 (rSjP40) could inhibit activation of hepatic stellate cells (HSCs) through the TGF-β1/Smads signaling pathway. Since multiple microRNAs could play essential roles in HSC activation and in the process of hepatic fibrosis through targeting Smads, we attempted to seek the potential microRNAs that could be involved in rSjP40-induced inhibition of HSC activation. Using the method of quantitative real-time PCR, we found that rSjP40 could induce miR-146a expression in LX-2 cells. The down-regulated expression levels of Smad4 and α-SMA in LX-2 cells induced by rSjP40 were partially restored by an miR-146a inhibitor. miR-146a can be involved in rSjP40-induced inhibition of HSC activation through targeting Smad4. These findings provide us a new idea to explore the potential mechanisms by which rSjP40 could regulate the process of hepatic fibrosis.

Recombinant SjP40 protein enhances p27 promoter expression in hepatic stellate cells via an E2F1-dependent mechanism

The p27 protein plays a critical role in cell cycle arrest. Our previous studies have demonstrated that recombinant P40 protein from Schistosoma japonicum (rSjP40) could induce G1 phase arrest of cell cycle. We, therefore, attempted to observe the effect of rSjP40 on p27 promoter activity in LX-2 cells and to explore its potential mechanisms in this study. Using both Western blot and dual-luciferase reporter assay, we demonstrated that rSjP40 could enhance the expression of p27 in LX-2 cells. Results obtained using truncated fragments of p27 promoter showed that rSjP40 increased p27 promoter activity in LX-2 cells, mainly via some transcription factors that bind to the -1740/-873 region of p27 promoter. Further studies confirmed that the enhancement of p27 promoter activity induced by rSjP40 was related to E2F1 in LX-2 cells. Transfection of siRNA of E2F1 could also restore the effect of rSjP40 on expression of p27 and partially on α-SMA. Therefore, our study provided further insights into the mechanism by which rSjP40 induces LX-2 cell cycle arrest at G1 phase and inhibits HSC activation. Our results provide basis for future study of the blocking effect of rSjP40 in liver fibrosis.

rSjP40 protein promotes PPARγ expression in LX-2 cells through microRNA-27b

miR-27b is reported to participate in the proliferation and differentiation of hepatic stellate cells (HSCs) and to regulate fat metabolism of rat HSCs by targeting retinoid X receptor α. Our previous study also indicated that the recombinant P40 protein from Schistosoma japonicum (rSjP40) inhibited the activation of HSCs. In this study, we observed the expression of miR-27b in rSjP40-treated LX-2 cells and explored its potential mechanisms. Quantitative real-time PCR showed that rSjP40 inhibits the expression of miR-27b in LX-2 cells. Further results obtained by Western blot and dual-luciferase reporter assay confirmed that miR-27b regulates peroxisome proliferator-activated receptor γ (PPARγ) expression in rSjP40-treated LX-2 cells by targeting the 3'-UTR of PPARγ. 5-AZA-2'-deoxycytidine (5-AZA-dC), which inhibits methylation of HSCs, partially reversed rSjP40-induced down-regulation expression of miR-27b in LX-2 cells. 5-AZA-dC also partially reversed rSjP40-induced up-regulation expression of PPARγ in LX-2 cells. The increased expression of PPARγ in rSjP40-treated LX-2 cells may be partially due to miR-27b methylation. Therefore, our study provides further insight into the mechanism by which rSjP40 inhibits HSC activation and provides a basis for future study of the blocking effect of rSjP40 in liver fibrosis.-Zhu, D., Lyu, L., Shen, P., Wang, J., Chen, J., Sun, X., Chen, L., Zhang, L., Zhou, Q., Duan, Y. rSjP40 protein promotes PPARγ expression in LX-2 cells through microRNA-27b.

Schistosome-Induced Fibrotic Disease: The Role of Hepatic Stellate Cells

Hepatic fibrosis is a common pathology in various liver diseases. Hepatic stellate cells (HSCs) are the main cell type responsible for collagen deposition and fibrosis formation in the liver. Schistosomiasis is characterised by granulomatous fibrosis around parasite eggs trapped within the liver and other host tissues. This response is facilitated by the recruitment of immune cells and the activation of HSCs. The interactions between HSCs and schistosome eggs are complex and diverse, and a better understanding of these interactions could lead to improved resolution of fibrotic liver disease, including that associated with schistosomiasis. Here, we discuss recent advances in HSC biology and the role of HSCs in hepatic schistosomiasis.

Impact of treatment with a Protein Tyrosine Kinase Inhibitor (Genistein) on acute and chronic experimental Schistosoma mansoni infection

Schistosomiasis mansoni is considered one of the most common fibrotic diseases resulting from inflammation and deposition of fibrous tissue around parasitic eggs trapped in the liver, causing morbidity and mortality. Chemotherapy against schistosomiasis is largely dependent on Praziquantel (PZQ). Yet, the huge administration of it in endemic areas and its incompetence towards the immature stages have raised serious alarms against the development of drug resistance. Few drugs are directed to reverse schistosomal liver fibrosis, particularly at the chronic and advanced stages of the disease. Recently, protein tyrosine kinase (PTK) inhibitors have been identified as potent anti-schistosomal and anti-fibrotic drugs against schistosomes, that may suppress and reverse Schistosoma mansoni (S. mansoni) induced liver fibrosis. The present study was designed to assess the anti-schistosomal and antifibrotic activity of Genistein, a PTK inhibitor, in comparison to PZQ, on both acute and chronic S. mansoni-infected mice using different parasitological, histopathological and immunohistochemical studies. Genistein showed a significant reduction (P < .05) in total worm burden, tissue egg load, mean hepatic granulomas diameter and numbers, percentage of collagen and expression of transforming growth factor-beta 1 (TGF-β 1) in the examined hepatocytes with elevation in percentage of degenerated ova, in comparison to the control groups, in both acute and chronic stages of infection. The best results were obtained when Genistein was combined with PZQ. Therefore, it was concluded that Genistein showed a promising anti-schistosomal and anti-fibrotic properties which could make it one of the new potential targets in chemotherapy against schistosomiasis.

Genistein improves schistosomiasis liver granuloma and fibrosis via dampening NF-kB signaling in mice

In schistosomiasis, egg deposition in the liver contributes to the formation of hepatic granuloma and fibrosis, which are the most serious clinical pathological features. It has been proposed that activation of the nuclear factor kappa B (NF-κB) signaling pathways is closely associated with the development of hepatic granuloma and fibrosis. Genistein has been shown to inhibit the activity of NF-κB signaling pathways, which might be a potential agent to protect against Schistosoma japonicum egg-induced liver granuloma and fibrosis. In this study, liver granuloma and fibrosis were induced by infecting BALB/c mice with 18 ± 3 cercariae of S. japonicum. At the beginning of egg granuloma formation (early phase genistein treatment from 4 to 6 weeks after infection) or after the formation of liver fibrosis (late phase genistein treatment from 6 to 10 weeks after infection), the infected mice were injected with genistein (25, 50 mg/kg). The results revealed that genistein treatment significantly decreased the extent of hepatic granuloma and fibrosis in infected mice. The activity of NF-κB signaling declined sharply after the treatment with genistein, as evidenced by the inhibition of NF-κB-p65, phospho-NF-κB-p65, and phospo-IκB-α expressions, as well as the expression of IκB-α and the messenger RNA (mRNA) expression of inflammatory cytokines (MCP1, TNFα, IL1β, IL4, IL10) mediated by NF-κB signaling pathways in the early phase of the infection. Moreover, western blot and immunohistochemistry assays demonstrated that the contents of α-smooth muscle actin (α-SMA) and transforming growth factor-β were dramatically reduced in liver tissue under the treatment of genistein in the late phase of the infection. At the same time, the mRNA expression of MCP1, TNFα, and IL10 was inhibited markedly. These results provided evidence that genistein reduces S. japonicum egg-induced liver granuloma and fibrosis, at least partly due to decreased NF-κB signaling, and subsequently decreased MCP1, TNFα, and IL10 expressions. This implies that genistein can be a potential natural agent against schistosomiasis.

Egg antigen p40 of Schistosoma japonicum promotes senescence in activated hepatic stellate cells via SKP2/P27 signaling pathway

Schistosomiasis is characterized by egg deposition, granulomatous inflammatory reaction and then subsequent hepatic fibrosis formation. Activated HSCs are regarded as the main effector cells in the progression of liver fibrosis and induction of senescence in hepatic stellate cells (HSCs) is vital to the reversion of hepatic fibrosis. Our previous work has showed that S. japonicum egg antigen p40 (Sjp40) could promote HSCs senescence via a STAT3/p53/p21 mechanism. In this paper, the major aim was to explore whether there are other signaling pathways in the process of Sjp40-induced HSCs aging and the underlying effect of SKP2/P27 signal pathway in this procedure. We observed the Sjp40-induced decrease of α-SMA and the senescence of LX-2 cells, and Sjp40 could upregulate P27 and downregulate the protein level of SKP2. The senescence induced by Sjp40 might be reversed in LX-2 cells that treated with P27-specific siRNA or with SKP2-special over-expression plasmid. In addition, we also demonstrated that the decreased expression of P-Rb and α-SMA induced by Sjp40 were partly restored by SKP2-overexpression. These data suggest that Sjp40 might inhibit HSCs activation by promoting cellular senescence via SKP2/P27 signaling pathway, which put forward novel mechanism in the treatment of liver fibrosis.

Egg antigen p40 of Schistosoma japonicum promotes senescence in activated hepatic stellate cells by activation of the STAT3/p53/p21 pathway

Liver fibrosis is a serious disease that is characterized by the excess deposition of extracellular matrix (ECM) components. Activated hepatic stellate cells (HSCs) are a major source of ECM and serve as a key regulator in liver fibrogenesis. Inactivation of HSCs is essential for liver fibrotic regression. The present study explores the underlying mechanisms of Schistosoma japonicum egg antigen p40 (Sjp40) promoting senescence in HSCs and antifibrosis. For the first time we report that Sjp40 inhibits the activation and proliferation of an immortalized human HSC line (LX-2 cells) and promotes cellular senescence and cell cycle arrest. Sjp40 through action on the STAT3/p53/p21 pathway triggered cellular senescence, while knockdown of p53 or STAT3 partly restored cell senescence. In addition, Sjp40-induced cellular senescence caused LX-2 cells to be more sensitive to a human NK cell line (YT cells). Together these findings provide novel insights into the mechanism of antifibrosis and may have implications for the development of antifibrosis therapies.

Hydroxysafflor yellow A inhibits TGF-β1-induced activation of human fetal lung fibroblasts in vitro

Objective

Hydroxysafflor yellow A (HSYA) is one of the chemical component isolated from Chinese medicine Carthamus tinctorius L. Our preliminary study confirmed that HSYA attenuated bleomycin-induced pulmonary fibrosis in mice. In this study, we evaluated the effect of HSYA on TGF-β1-induced activation of human fetal lung fibroblasts (MRC-5) and explored the underlying mechanisms of its activity.

Method

MRC-5 cells activated by TGF-β1 were incubated with HSYA and/or the TGF-β type I receptor inhibitor, SB431542. TGF-β1-induced cell proliferation, α-smooth muscle actin, collagen I alpha 1 and fibronectin expression, Smad, mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3 kinase/Akt signalling pathway activation were observed.

Key findings

Hydroxysafflor yellow A significantly inhibited TGF-β1-induced cell proliferation and the expression, both mRNA and protein, of α-smooth muscle actin, collagen I alpha 1 and fibronectin. HSYA also suppressed TGF-β1 activation of Smad signal transduction via inhibition of Smad2 and Smad3 phosphorylation, their nuclear translocation and the binding activity of Smad3 to type I collagen promoter in MRC-5 cells. In addition, HSYA inhibited TGF-β1-induced phosphorylation of extracellular signal-regulated kinase (ERK). The inhibitory effects of HSYA were similar to SB431542.

Conclusion

These findings suggest that HSYA inhibits TGF-β1-induced activation of MRC-5 cells associated with TGF-β1/Smad and ERK/MAPK signalling pathways.

Taurine drinking ameliorates hepatic granuloma and fibrosis in mice infected with Schistosoma japonicum

In schistosomiasis, egg-induced hepatic granuloma formation is a cytokine-mediated, predominantly CD4⁺ Th2 immune response that can give rise to hepatic fibrosis. Hepatic fibrosis is the main cause of increased morbidity and mortality in humans with schistosome infection. Taurine has various physiological functions and hepatoprotective properties as well as anti-inflammatory and immunomodulatory activity. However, little is known about the role of taurine in schistosome egg-induced granuloma formation and fibrosis. We aimed to evaluate the therapeutic potential of taurine as preventative treatment for Schistosoma japonicum infection. Mice infected with S. japonicum cercariae were supplied with taurine drinking water (1% w/v) for 4 weeks starting at 4 weeks post-infection. Taurine supplementation significantly improved the liver pathologic findings, reduced the serum levels of aminotransferases and area of hepatic granuloma, and prevented fibrosis progression. In addition, taurine decreased the expression of the granulomatous and fibrogenic mediators transforming growth factor β1, tumor necrosis factor α, monocyte chemotactic protein 1α and macrophage inflammatory protein 1α as well as the endoplasmic reticulum stress marker glucose-regulated protein 78. Thus, taurine can significantly attenuate S. japonicum egg-induced hepatic granuloma and fibrosis, which may depend in part on the downregulation of some relevant cytokine/chemokines and reducing the endoplasmic reticulum stress response.

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Taurine has potential as preventative & therapeutic treatment for schistosomiasis.

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Taurine reduced the development of liver pathology caused by S. japonicum infection.

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Taurine attenuated S. japonicum egg-induced hepatic granuloma and fibrosis.