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

Research progress in the treatment of schistosomiasis with traditional Chinese medicine

ETHNOPHARMACOLOGICAL RELEVANCE

Schistosomiasis, caused by infection with organisms of the Schistoma genus, is a parasitic and infectious disease that poses a significant risk to human health. Schistosomiasis has been a widespread issue in China for at least 2000 years. Traditional Chinese medicine (TCM) has a rich history of treating this disease, and the significant theoretical and practical knowledge attained therein may be useful in modern practice.

AIM OF THE STUDY

To comprehensively review TCM for the treatment of schistosomiasis, summarize the molecular basis, mechanism of action, active ingredients and formulas of TCM, and clarify the value of TCM for expanding drug options for the clinical treatment of schistosomiasis.

MATERIALS AND METHODS

In PubMed, Web of Science, ScienceDirect, Google Scholar and CNKI databases, "Schistosomiasis", "Schistosoma mansoni", "Schistosoma japonicum", "Liver fibrosis" and "Granuloma" were used as the key words. Information related to in vivo animal studies and clinical studies of TCM for the treatment of schistosomiasis in the past 25 years was retrieved, and the inclusion criteria focused on medicinal plants that had a history of use in China.

RESULTS

In this study, we collected and organized a large amount of literature on the treatment of schistosomiasis by TCM. TCM exerts therapeutic effects through antischistosomal and immunomodulatory effects, suppresses HSC activation and proliferation, reduces ECM deposition, and inhibits oxidative stress and other activities. The treatment of schistosomiasis by TCM has a unique advantage, especially for the treatment of schistosomal liver fibrosis, and the treatment of schistosomiasis with TCM in combination with praziquantel is superior to monotherapy.

CONCLUSION

Schistosomiasis remains a global public health problem, and TCM has made significant progress in the prevention and treatment of schistosomiasis and is a potential source of drugs for the treatment of schistosomiasis. However, research on drug screening and the mechanism of action of TCM for the treatment of schistosomiasis is lacking, and further studies and research are needed.

The role of taurine through endoplasmic reticulum in physiology and pathology

Taurine is a sulfur-containing amino acid found in many cell organelles that plays a wide range of biological roles, including bile salt production, osmoregulation, oxidative stress reduction, and neuromodulation. Taurine treatments have also been shown to ameliorate the onset and development of many diseases, including hypertension, fatty liver, neurodegenerative diseases and ischemia-reperfusion injury, by exerting antioxidant, anti-inflammatory, and antiapoptotic effects. The endoplasmic reticulum (ER) is a dynamic organelle involved in a wide range of cellular functions, including lipid metabolism, calcium storage and protein stabilization. Under stress, the disruption of the ER environment leads to the accumulation of misfolded proteins and a characteristic stress response called the unfolded protein response (UPR). The UPR protects cells from stress and helps to restore cellular homeostasis, but its activation promotes cell death under prolonged ER stress. Recent studies have shown that ER stress is closely related to the onset and development of many diseases. This article reviews the beneficial effects and related mechanisms of taurine by regulating the ER in different physiological and pathological states, with the aim of providing a reference for further research and clinical applications.

Molecular regulation of NLRP3 inflammasome activation during parasitic infection

Parasitic diseases are a serious global health concern, causing many common and severe infections, including Chagas disease, leishmaniasis, and schistosomiasis. The NLRP3 inflammasome belongs to the NLR (nucleotide-binding domain leucine-rich-repeat-containing proteins) family, which are cytosolic proteins playing key roles in the detection of pathogens. NLRP3 inflammasomes are activated in immune responses to Plasmodium, Leishmania, Toxoplasma gondii, Entamoeba histolytica, Trypanosoma cruzi, and other parasites. The role of NLRP3 is not fully understood, but it is a crucial component of the innate immune response to parasitic infections and its functions as a sensor triggering the inflammatory response to the invasive parasites. However, while this response can limit the parasites' growth, it can also result in potentially catastrophic host pathology. This makes it essential to understand how NLRP3 interacts with parasites to initiate the inflammatory response. Plasmodium hemozoin, Leishmania glycoconjugate lipophosphoglycan (LPG) and E. histolytica Gal/GalNAc lectin can stimulate NLRP3 activation, while the dense granule protein 9 (GRA9) of T. gondii has been shown to suppress it. Several other parasitic products also have diverse effects on NLRP3 activation. Understanding the mechanism of NLRP3 interaction with these products will help to develop advanced therapeutic approaches to treat parasitic diseases. This review summarizes current knowledge of the NLRP3 inflammasome's action on the immune response to parasitic infections and aims to determine the mechanisms through which parasitic molecules either activate or inhibit its action.

Metabolomics analysis of visceral leishmaniasis based on urine of golden hamsters

BACKGROUND

Leishmaniasis is one of the most neglected tropical diseases and is spread mainly in impoverished regions of the world. Although many studies have focused on the host's response to Leishmania invasion, relatively less is known about the complex processes at the metabolic level, especially the metabolic alterations in the infected hosts.

METHODS

In this study, we conducted metabolomics analysis on the urine of golden hamsters in the presence or absence of visceral leishmaniasis (VL) using the ultra-performance liquid chromatography (UPLC) system tandem high-resolution mass spectrometer (HRMS). The metabolic characteristics of urine samples, along with the histopathological change and the parasite burden of liver and spleen tissues, were detected at 4 and 12 weeks post infection (WPI), respectively.

RESULTS

Amino acid metabolism was extensively affected at both stages of VL progression. Meanwhile, there were also distinct metabolic features at different stages. At 4 WPI, the significantly affected metabolic pathways involved alanine, aspartate and glutamate metabolism, the pentose phosphate pathway (PPP), histidine metabolism, tryptophan metabolism and tyrosine metabolism. At 12 WPI, the markedly enriched metabolic pathways were almost concentrated on amino acid metabolism, including tyrosine metabolism, taurine and hypotaurine metabolism and tryptophan metabolism. The dysregulated metabolites and metabolic pathways at 12 WPI were obviously less than those at 4 WPI. In addition, seven metabolites that were dysregulated at both stages through partial least squares-discriminant analysis (PLS-DA) and receiver-operating characteristic (ROC) tests were screened to be of diagnostic potential. The combination of these metabolites as a potential biomarker panel showed satisfactory performance in distinguishing infection groups from control groups as well as among different stages of infection.

CONCLUSION

Our findings could provide valuable information for further understanding of the host response to Leishmania infection from the aspect of the urine metabolome. The proposed urine biomarker panel could help in the development of a novel approach for the diagnosis and prognosis of VL.

Dietary taurine supplementation counteracts deoxynivalenol-induced liver injury via alleviating oxidative stress, mitochondrial dysfunction, apoptosis, and inflammation in piglets

Deoxynivalenol (DON), as a widespread Fusarium mycotoxin in cereals, food products, and animal feed, is detrimental to both human and animal health. The liver is not only the primary organ responsible for DON metabolism but also the principal organ affected by DON toxicity. Taurine is well known to display various physiological and pharmacological functions due to its antioxidant and anti-inflammatory properties. However, the information regarding taurine supplementation counteracting DON-induced liver injury in piglets is still unclear. In our work, twenty-four weaned piglets were subjected to four groups for a 24-day period, including the BD group (a basal diet), the DON group (3 mg/kg DON-contaminated diet), the DON+LT group (3 mg/kg DON-contaminated diet + 0.3% taurine), and the DON+HT group (3 mg/kg DON-contaminated diet + 0.6% taurine). Our findings indicated that taurine supplementation improved growth performance and alleviated DON-induced liver injury, as evidenced by the reduced pathological and serum biochemical changes (ALT, AST, ALP, and LDH), especially in the group with the 0.3% taurine. Taurine could counteract hepatic oxidative stress in piglets exposed to DON, as it reduced ROS, 8-OHdG, and MDA concentrations and improved the activity of antioxidant enzymes. Concurrently, taurine was observed to upregulate the expression of key factors involved in mitochondrial function and the Nrf2 signaling pathway. Furthermore, taurine treatment effectively attenuated DON-induced hepatocyte apoptosis, as verified through the decreased proportion of TUNEL-positive cells and regulation of the mitochondria-mediated apoptosis pathway. Finally, the administration of taurine was able to reduce liver inflammation due to DON, by inactivating the NF-κB signaling pathway and declining the production of pro-inflammatory cytokines. In summary, our results implied that taurine effectively improved DON-induced liver injury. The underlying mechanism should be that taurine restored mitochondrial normal function and antagonized oxidative stress, thereby reducing apoptosis and inflammatory responses in the liver of weaned piglets.

Taurine metabolism is modulated in Vibrio-infected Penaeus vannamei to shape shrimp antibacterial response and survival

BACKGROUND

Numerous microorganisms are found in aquaculture ponds, including several pathogenic bacteria. Infection of cultured animals by these pathogens results in diseases and metabolic dysregulation. However, changes in the metabolic profiles that occur at different infection stages in the same ponds and how these metabolic changes can be modulated by exogenous metabolites in Penaeus vannamei remain unknown.

RESULTS

Here, we collected gastrointestinal tract (GIT) samples from healthy, diseased, and moribund P. vannamei in the same aquaculture pond for histological, metabolic, and transcriptome profiling. We found that diseased and moribund shrimp with empty GITs and atrophied hepatopancreas were mainly infected with Vibrio parahaemolyticus and Vibrio harveyi. Although significant dysregulation of crucial metabolites and their enzymes were observed in diseased and moribund shrimps, diseased shrimp expressed high levels of taurine and taurine metabolism-related enzymes, while moribund shrimp expressed high levels of hypoxanthine and related metabolism enzymes. Moreover, a strong negative correlation was observed between taurine levels and the relative abundance of V. parahaemolyticus and V. harveyi. Besides, exogenous taurine enhanced shrimp survival against V. parahaemolyticus challenge by increasing the expression of key taurine metabolism enzymes, mainly, cysteine dioxygenase (CDO) and cysteine sulfinic acid decarboxylase (CSD).

CONCLUSIONS

Our study revealed that taurine metabolism could be modulated by exogenous supplementation to improve crustacean immune response against pathogenic microbes. Video Abstract.

Pathology and molecular mechanisms of Schistosoma japonicum-associated liver fibrosis

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

Pattern recognition receptor signaling and innate immune responses to schistosome infection

Schistosomiasis remains to be a significant public health problem in tropical and subtropical regions. Despite remarkable progress that has been made in the control of the disease over the past decades, its elimination remains a daunting challenge in many countries. This disease is an inflammatory response-driven, and the positive outcome after infection depends on the regulation of immune responses that efficiently clear worms and allow protective immunity to develop. The innate immune responses play a critical role in host defense against schistosome infection and pathogenesis. Initial pro-inflammatory responses are essential for clearing invading parasites by promoting appropriate cell-mediated and humoral immunity. However, elevated and prolonged inflammatory responses against the eggs trapped in the host tissues contribute to disease progression. A better understanding of the molecular mechanisms of innate immune responses is important for developing effective therapies and vaccines. Here, we update the recent advances in the definitive host innate immune response to schistosome infection, especially highlighting the critical roles of pattern recognition receptors and cytokines. The considerations for further research are also provided.

Regulatory effects of Trichinella spiralis and a serine protease inhibitor on the endoplasmic reticulum stress response of intestinal epithelial cells

The accumulation of unfolded or misfolded proteins in the endoplasmic reticulum can cause an endoplasmic reticulum stress (ERS) response. If ERS continues or cannot be alleviated, it will cause the production of proapoptotic factors and eventually lead to apoptosis. Therefore, this study mainly explored whether Trichinella spiralis Kazal-type serine protease inhibitor (TsKaSPI) contributed to the invasion of intestinal epithelial cells during the infectious stage of T. spiralis by regulating ERS. First, in the T. spiralis infection model, H&E staining was used to analyse the damage to jejunum tissue, a TUNEL assay was used to examine cell apoptosis, and the expression of ERS-related and apoptosis-related molecules was also measured. The results showed that ERS occurred during the intestinal phase of T. spiralis infection, while remission began during the cyclic phase. Then, we selected TsKaSPI, one of the important components of T. spiralis ES antigens, for in vitro experiments. The results showed that TsKaSPI could induce apoptosis in a porcine small intestinal epithelial cell line (IPEC cells) by activating ERS and promote activation of the NF-κB signalling pathway. Inhibition experiments confirmed that the occurrence of ERS was accompanied by the activation of NF-κB, and the two processes regulated each other. Finally, we conducted in vivo experiments and administered TsKaSPI to mice. The results confirmed that TsKaSPI could activate ERS and lead to apoptosis in intestinal epithelial cells. In conclusion, T. spiralis infection and TsKaSPI can promote cell apoptosis by activating the ERS response in intestinal epithelial cells and activate the NF-κB signalling pathway to promote the occurrence and development of inflammation.

Endoplasmic Reticulum Stress, a Target for Drug Design and Drug Resistance in Parasitosis

Endoplasmic reticulum stress (ER stress) can be induced when cellular protein homeostasis is damaged, and cells can activate the unfolded protein response (UPR) to restore protein homeostasis or induce cell death to facilitate the survival of the whole system. Globally, parasites are a constant threat to human health and are therefore considered a serious public health problem. Parasitic infection can cause ER stress in host cells, and parasites also possess part or all of the UPR under ER stress conditions. In this review, we aim to clarify the role of ER stress pathways and related molecules in parasites for their survival and development, the pathogenesis of parasitosis in hosts, and the artemisinin resistance of Plasmodium, which provides some potential drug design targets to inhibit survival of parasites, relieves pathological damage of parasitosis, and solves the problem of artemisinin resistance.

The role of microRNAs in the pathogenesis, grading and treatment of hepatic fibrosis in schistosomiasis

Schistosomiasis is a prevalent parasitic disease worldwide. The main pathological changes of hepatosplenic schistosomiasis are hepatic granuloma and fibrosis due to worm eggs. Portal hypertension and ascites induced by hepatic fibrosis are usually the main causes of death in patients with chronic hepatosplenic schistosomiasis. Currently, no effective vaccine exists for preventing schistosome infections. For quite a long time, praziquantel (PZQ) was widely used for the treatment of schistosomiasis and has shown benefit in treating liver fibrosis. However, drug resistance and chemical toxicity from PZQ are being increasingly reported in recent years; therefore, new and effective strategies for treating schistosomiasis-induced hepatic fibrosis are urgently needed. MicroRNA (miRNA), a non-coding RNA, has been proved to be associated with the development of many human diseases, including schistosomiasis. In this review, we present a balanced and comprehensive view of the role of miRNAs in the pathogenesis, grading, and treatment of schistosomiasis-associated hepatic fibrosis. The multiple regulatory roles of miRNAs, such as promoting or inhibiting the development of liver pathology in murine schistosomiasis are also discussed in depth. Additionally, miRNAs may serve as candidate biomarkers for diagnosing liver pathology of schistosomiasis and as novel therapeutic targets for treating schistosomiasis-associated hepatic fibrosis.

C/EBP Homologous Protein (CHOP) Activates Macrophages and Promotes Liver Fibrosis in Schistosoma japonicum-Infected Mice

CCAAT/enhancer-binding homologous protein (CHOP), a transcriptional regulator induced by endoplasmic reticulum stress (ER stress) is a pivotal factor in the ER stress-mediated apoptosis pathway. Previous studies have shown that CHOP is involved in the formation of fibrosis in a variety of tissues and is associated with alternative macrophage activation. The role of CHOP in the pathologic effects of liver fibrosis in schistosomiasis has not been reported, and underlying mechanisms remain unclear. This study is aimed at understanding the effect of CHOP on liver fibrosis induced by Schistosoma japonicum (S. japonicum) in vivo and clarifying its mechanism. C57BL/6 mice were infected with cercariae of S. japonicum through the abdominal skin. The liver fibrosis was examined. The level of IL-13 was observed. The expressions of CHOP, Krüppel-like factor 4 (KLF4), signal transducer and activator of transcription 6 (STAT6), phosphorylation STAT6, interleukin-13 receptor alpha 1 (IL-13Rα1), and interleukin-4 receptor alpha (IL-4Rα) were analysed. The eosinophilic granuloma and collagen deposition were found around the eggs in mice infected for 6 and 10 weeks. IL-13 in plasma and IL-13Rα1 and IL-4Rα in liver tissue were significantly increased. The phosphorylated STAT6 was enhanced while Krüppel-like factor 4 (KLF4) was decreased in liver tissue. The expression of CHOP and colocalization of CHOP and CD206 were increased. Overall, these results suggest that CHOP plays a critical role in hepatic fibrosis induced by S. japonicum, likely through promoting alternative activation of macrophages.

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.

Identification of Piecemeal Degranulation and Vesicular Transport of MBP-1 in Liver-Infiltrating Mouse Eosinophils During Acute Experimental Schistosoma mansoni Infection

Eosinophils have been long associated with helminthic infections, although their functions in these diseases remain unclear. During schistosomiasis caused by the trematode Schistosoma mansoni, eosinophils are specifically recruited and migrate to sites of granulomatous responses where they degranulate. However, little is known about the mechanisms of eosinophil secretion during this disease. Here, we investigated the degranulation patterns, including the cellular mechanisms of major basic protein-1 (MBP-1) release, from inflammatory eosinophils in a mouse model of S. mansoni infection (acute phase). Fragments of the liver, a major target organ of this disease, were processed for histologic analyses (whole slide imaging), conventional transmission electron microscopy (TEM), and immunonanogold EM using a pre-embedding approach for precise localization of major basic protein 1 (MBP-1), a typical cationic protein stored pre-synthesized in eosinophil secretory (specific) granules. A well-characterized granulomatous inflammatory response with a high number of infiltrating eosinophils surrounding S. mansoni eggs was observed in the livers of infected mice. Moreover, significant elevations in the levels of plasma Th2 cytokines (IL-4, IL-13, and IL-10) and serum enzymes (alanine aminotransferase and aspartate aminotransferase) reflecting altered liver function were detected in response to the infection. TEM quantitative analyses revealed that while 19.1% of eosinophils were intact, most of them showed distinct degranulation processes: cytolysis (13.0%), classical and/or compound exocytosis identified by granule fusions (1.5%), and mainly piecemeal degranulation (PMD) (66.4%), which is mediated by vesicular trafficking. Immunonanogold EM showed a consistent labeling for MBP-1 associated with secretory granules. Most MBP-1-positive granules had PMD features (79.0 ± 4.8%). MBP-1 was also present extracellularly and on vesicles distributed in the cytoplasm and attached to/surrounding the surface of emptying granules. Our data demonstrated that liver-infiltrating mouse eosinophils are able to degranulate through different secretory processes during acute experimental S. mansoni infections with PMD being the predominant mechanism of eosinophil secretion. This means that a selective secretion of MBP-1 is occurring. Moreover, our study demonstrates, for the first time, a vesicular trafficking of MBP-1 within mouse eosinophils elicited by a helminth infection. Vesicle-mediated secretion of MBP-1 may be relevant for the rapid release of small concentrations of MBP-1 under cell activation.

Schistosoma japonicum attenuates dextran sodium sulfate-induced colitis in mice via reduction of endoplasmic reticulum stress

AIM

To elucidate the impact of Schistosoma (S.) japonicum infection on inflammatory bowel disease by studying the effects of exposure to S. japonicum cercariae on dextran sodium sulfate (DSS)-induced colitis.

METHODS

Infection was percutaneously established with 20 ± 2 cercariae of S. japonicum, and colitis was induced by administration of 3% DSS at 4 wk post infection. Weight change, colon length, histological score (HS) and disease activity index (DAI) were evaluated. Inflammatory cytokines, such as IL-2, IL-10 and IFN-γ, were tested by a cytometric bead array and real-time quantitative polymerase chain reaction (RT-PCR). Protein and mRNA levels of IRE1α, IRE1β, GRP78, CHOP, P65, P-P65, P-IκBα and IκBα in colon tissues were examined by Western blot and RT-PCR, respectively. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling positive cells, cleaved-caspase 3 expression and Bcl2/Bax were investigated to assess the apoptosis in colon tissues.

RESULTS

Mice infected with S. japonicum cercariae were less susceptible to DSS. Mice infected with S. japonicum cercariae and treated with DSS showed decreased weight loss, longer colon, and lower HS and DAI compared with mice treated with DSS alone. A substantial decrease in Th1/Th2/Th17 response was observed after infection with S. japonicum. Endoplasmic reticulum (ER) stress and the nuclear factor-kappa B (NF-κB) pathway were reduced in mice infected with S. japonicum cercariae and treated with DSS, along with ameliorated celluar apoptosis, in contrast to mice treated with DSS alone.

CONCLUSION

Exposure to S. japonicum attenuated inflammatory response in a DSS-induced colitis model. In addition to the Th1/Th2/Th17 pathway and NF-κB pathway, ER stress was shown to be involved in mitigating inflammation and decreasing apoptosis. Thus, ER stress is a new aspect in elucidating the relationship between helminth infection and inflammatory bowel disease (IBD), which may offer new therapeutic methods for IBD.

Natural Schistosoma mansoni Infection in the Wild Reservoir Nectomys squamipes Leads to Excessive Lipid Droplet Accumulation in Hepatocytes in the Absence of Liver Functional Impairment

Schistosomiasis is a neglected tropical disease of a significant public health impact. The water rat Nectomys squamipes is one of the most important non-human hosts in the schistosomiasis mansoni transmission in Brazil, being considered a wild reservoir. Cellular mechanisms that contribute to the physiological adaptation of this rodent to the Schistosoma mansoni parasite are poorly understood. Here we identified, for the first time, that a hepatic steatosis, a condition characterized by excessive lipid accumulation with formation of lipid droplets (LDs) within hepatocytes, occurs in response to the natural S. mansoni infection of N. squamipes, captured in an endemic region. Significant increases of LD area in the hepatic tissue and LD numbers/hepatocyte, detected by quantitative histopathological and ultrastructural analyses, were paralleled by increased serum profile (total cholesterol and triglycerides) in infected compared to uninfected animals. Raman spectroscopy showed high content of polyunsaturated fatty acids (PUFAs) in the liver of both groups. MALDI-TOFF mass spectroscopy revealed an amplified pool of omega-6 PUFA arachidonic acid in the liver of infected animals. Assessment of liver functional activity by the levels of hepatic transaminases (ALT and AST) did not detect any alteration during the natural infection. In summary, this work demonstrates that the natural infection of the wild reservoir N. squamipes with S. mansoni elicits hepatic steatosis in the absence of liver functional harm and that accumulation of lipids, markedly PUFAs, coexists with low occurrence of inflammatory granulomatous processes, suggesting that lipid stores may be acting as a protective mechanism for dealing with the infection.

The role of Ca(2+) mediated signaling pathways on the effect of taurine against Streptococcus uberis infection

To provide insight into the mechanisms of taurine attenuation of pro-inflammatory response in mouse mammary epithelial cell line (EpH4-Ev, purchased by ATCC, USA) after Streptococcus uberis (S. uberis, 0140J) challenge, we infected MECs with S. uberis (2.5×10(7)cfumL(-1), MOI=10) for 3h and quantified changes in TLR-2 and calcium (Ca(2+)) mediated signaling pathways. The results indicate that S. uberis infection significantly increases the expression of TLR-2, intracellular Ca(2+) levels, PLC-γ1 and PKC-α, the activities of transcription factors NF-κB and NFAT, and related cytokines (TNF-α, IL-1β, IL-6, G-CSF, IL-2, KC, IL-15, FasL, MCP-1, and LIX) in culture supernatants. Taurine administration downregulated all these indices, the activities of NF-κB and NFAT. Cytokine secretions were similar using special PKC inhibitor Go 6983 and NFAT inhibitor VIVIT. Our data indicate that S. uberis infection induces pro-inflammatory response of MECs through a TLR-2 mediated signaling pathway. In addition, taurine can prevent MEC damage by affecting both PLC-γ1-Ca(2+)-PKC-α-NF-κB and PLC-γ1-Ca(2+)-NFATs signaling pathways. This is the first report to demonstrate the mechanisms of taurine attenuated pro-inflammatory response in MECs after S. uberis challenge.