Worm proteins of Schistosoma mansoni reduce the severity of experimental chronic colitis in mice by suppressing colonic proinflammatory immune responses

Helminth-derived proteins as immune system regulators: a systematic review of their promise in alleviating colitis

Helminth-derived proteins have immunomodulatory properties, influencing the host's immune response as an adaptive strategy for helminth survival. Helminth-derived proteins modulate the immune response by inducing anti-inflammatory cytokines, promoting regulatory T-cell development, and ultimately favouring a Th2-biased immune response. This systematic review focused on helminth-derived proteins and explored their impact on reducing inflammatory responses in mouse models of colitis. A systematic search across Medline, EMBASE, Web of Science, and Cochrane Library identified fourteen relevant studies. These studies reported immunomodulatory changes, including increased production of anti-inflammatory cells and cytokines. In mouse models of colitis treated with on helminth-derived proteins, significant improvements in pathological parameters such as body weight, colon length, and microscopic inflammatory scores were observed compared to control groups. Moreover, helminth-derived proteins can enhance the function of Tregs and alleviate the severity of inflammatory conditions. The findings underscore the pivotal role of helminth-derived proteins in immunomodulation, specifically in the axis of cytokine secretion and immune cell polarization. The findings offer new opportunities for treating chronic inflammatory conditions such Crohn's disease.

Perineuronal net in the extrinsic innervation of the distal colon of mice and its remodeling in ulcerative colitis

The perineuronal net (PNN) is a well-described highly specialized extracellular matrix structure found in the central nervous system. Thus far, no reports of its presence or connection to pathological processes have been described in the peripheral nervous system. Our study demonstrates the presence of a PNN in the spinal afferent innervation of the distal colon of mice and characterizes structural and morphological alterations induced in an ulcerative colitis (UC) model. C57Bl/6 mice were given 3% dextran sulfate sodium (DSS) to induce acute or chronic UC. L6/S1 dorsal root ganglia (DRG) were collected. PNNs were labeled using fluorescein-conjugated Wisteria Floribunda (WFA) l lectin, and calcitonin gene-related peptide (CGRP) immunofluorescence was used to detect DRG neurons. Most DRG cell bodies and their extensions toward peripheral nerves were found surrounded by the PNN-like structure (WFA+), labeling neurons' cytoplasm and the pericellular surfaces. The amount of WFA+ neuronal cell bodies was increased in both acute and chronic UC, and the PNN-like structure around cell bodies was thicker in UC groups. In conclusion, a PNN-like structure around DRG neuronal cell bodies was described and found modulated by UC, as changes in quantity, morphology, and expression profile of the PNN were detected, suggesting a potential role in sensory neuron peripheral sensitization, possibly modulating the pain profile of ulcerative colitis.

Inhibition of GSDMD-mediated pyroptosis triggered by Trichinella spiralis intervention contributes to the alleviation of DSS-induced ulcerative colitis in mice

BACKGROUND

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is increasing worldwide. Although there is currently no completely curative treatment, helminthic therapy shows certain therapeutic potential for UC. Many studies have found that Trichinella spiralis (T.s) has a protective effect on UC, but the specific mechanism is still unclear.

METHODS

Balb/c mice drank dextran sulfate sodium (DSS) to induce acute colitis and then were treated with T.s. In vitro experiments, the LPS combination with ATP was used to induce the pyroptosis model, followed by intervention with crude protein from T.s (T.s cp). Additionally, the pyroptosis agonist of NSC or the pyroptosis inhibitor vx-765 was added to intervene to explore the role of pyroptosis in DSS-induced acute colitis. The degree of pyroptosis was evaluated by western blot, qPCR and IHC, etc., in vivo and in vitro.

RESULTS

T.s intervention significantly inhibited NLRP3 inflammasome activation and GSDMD-mediated pyroptosis by downregulating the expression of pyroptosis-related signatures in vitro (cellular inflammatory model) and in vivo (DSS-induced UC mice model). Furthermore, blockade of GSDMD-mediated pyroptosis by the caspase-1 inhibitor vx-765 has a similar therapeutic effect on DSS-induced UC mice with T.s intervention, thus indicating that T.s intervention alleviated DSS-induced UC in mice by inhibiting GSDMD-mediated pyroptosis.

CONCLUSION

This study showed that T.s could alleviate the pathological severity UC via GSDMD-mediated pyroptosis, and it provides new insight into the mechanistic study and application of helminths in treating colitis.

Potential of human helminth therapy for resolution of inflammatory bowel disease: The future ahead

Inflammatory bowel disease (IBD) is associated with a dysregulated mucosal immune response in the gastrointestinal tract. The number of patients with IBD has increased worldwide, especially in highly industrialized western societies. The population of patients with IBD in North America is forecasted to reach about four million by 2030; meanwhile, there is no definitive therapy for IBD. Current anti-inflammatory, immunosuppressive, or biological treatment may induce and maintain remission, but not all patients respond to these treatments. Recent studies explored parasitic helminths as a novel modality of therapy due to their potent immunoregulatory properties in humans. Research using IBD animal models infected with a helminth or administered helminth-derived products such as excretory-secretory products has been promising, and helminth-microbiota interactions exert their anti-inflammatory effects by modulating the host immunity. Recent studies also indicate that evidence that helminth-derived metabolites may play a role in anticolitic effects. Thus, the helminth shows a potential benefit for treatment against IBD. Here we review the current feasibility of "helminth therapy" from the laboratory for application in IBD management.

An Update on the Role of Extracellular Vesicles in the Pathogenesis of Necrotizing Enterocolitis and Inflammatory Bowel Diseases

Some of the most fundamental influences of microorganisms inhabiting the human intestinal tract are exerted during infant development and impact the maturation of intestinal mucosa and gut immune system. The impact of bacteria on the host gut immune system is partially mediated via released extracellular vesicles (EVs). The heterogeneity in EV content, size, and bacterial species origin can have an impact on intestinal cells, resulting in inflammation and an immune response, or facilitate pathogen entry into the gut wall. In mammals, maintaining the integrity of the gut barrier might also be an evolutionary function of maternal milk EVs. Recently, the usage of EVs has been explored as a novel therapeutic approach in several pathological conditions, including necrotizing enterocolitis (NEC) and inflammatory bowel disease (IBD). In this review, we attempt to summarize the current knowledge of EV biology, followed by a discussion of the role that EVs play in gut maturation and the pathogenesis of NEC and IBD.

The Effect of a Novel Serine Protease Inhibitor on Inflammation and Intestinal Permeability in a Murine Colitis Transfer Model

Background: A protease/antiprotease disbalance is observed in inflammatory bowel diseases (IBD). We therefore studied the effect of the novel serine protease inhibitor UAMC-00050 on intestinal inflammation and permeability in a chronic colitis T cell transfer mouse model to get further insight into the regulation of T cell-mediated immunopathology. Methods: Colitis was induced in severe combined immunodeficient (SCID) mice, by the adoptive transfer of CD4⁺CD25^-CD62L⁺ T cells. Animals were treated intraperitoneally (i.p.) 2x/day with vehicle or UAMC-00050 (5 mg/kg) from week 2 onwards. Colonic inflammation was assessed by clinical parameters, colonoscopy, macroscopy, microscopy, myeloperoxidase activity and cytokine expression levels. At week 4, 4 kDa FITC-dextran intestinal permeability was evaluated and T helper transcription factors, protease-activated receptors and junctional proteins were quantified by RT-qPCR. Results: Adoptive transfer of CD4⁺CD25^-CD62L⁺ T cells resulted in colonic inflammation and an altered intestinal permeability. The serine protease inhibitor UAMC-00050 ameliorated both the inflammatory parameters and the intestinal barrier function. Furthermore, a decrease in colonic mRNA expression of Tbet and PAR4 was observed in colitis mice after UAMC-00050 treatment. Conclusion: The beneficial effect of UAMC-00050 on inflammation was apparent via a reduction of Tbet, IFN-γ, TNF-α, IL-1β and IL-6. Based on these results, we hypothesize a pivotal effect of serine protease inhibition on the Th1 inflammatory profile potentially mediated via PAR4.

Schistosoma mansoni eggs induce Wnt/β-catenin signaling and activate the protooncogene c-Jun in human and hamster colon

Schistosomiasis (bilharzia) is a neglected tropical disease caused by parasitic flatworms of the genus Schistosoma, with considerable morbidity in parts of the Middle East, South America, Southeast Asia, in sub-Saharan Africa, and particularly also in Europe. The WHO describes an increasing global health burden with more than 290 million people threatened by the disease and a potential to spread into regions with temperate climates like Corsica, France. The aim of our study was to investigate the influence of S. mansoni infection on colorectal carcinogenic signaling pathways in vivo and in vitro. S. mansoni infection, soluble egg antigens (SEA) and the Interleukin-4-inducing principle from S. mansoni eggs induce Wnt/β-catenin signaling and the protooncogene c-Jun as well as downstream factor Cyclin D1 and markers for DNA-damage, such as Parp1 and γH2a.x in enterocytes. The presence of these characteristic hallmarks of colorectal carcinogenesis was confirmed in colon biopsies from S. mansoni-infected patients demonstrating the clinical relevance of our findings. For the first time it was shown that S. mansoni SEA may be involved in the induction of colorectal carcinoma-associated signaling pathways.

In-Depth Study of Transmembrane Mucins in Association with Intestinal Barrier Dysfunction During the Course of T Cell Transfer and DSS-Induced Colitis

BACKGROUND AND AIMS

There is evidence for a disturbed intestinal barrier function in inflammatory bowel diseases [IBD] but the underlying mechanisms are unclear. Because mucins represent the major components of the mucus barrier and disturbed mucin expression is reported in the colon of IBD patients, we studied the association between mucin expression, inflammation and intestinal permeability in experimental colitis.

METHODS

We quantified 4-kDa FITC-dextran intestinal permeability and the expression of cytokines, mucins, junctional and polarity proteins at dedicated time points in the adoptive T cell transfer and dextran sodium sulfate [DSS]-induced colitis models. Mucin expression was also validated in biopsies from IBD patients.

RESULTS

In both animal models, the course of colitis was associated with increased interleukin-1β [IL-1β] and tumour necrosis factor-α [TNF-α] expression and increased Muc1 and Muc13 expression. In the T cell transfer model, a gradually increasing Muc1 expression coincided with gradually increasing 4-kDa FITC-dextran intestinal permeability and correlated with enhanced IL-1β expression. In the DSS model, Muc13 expression coincided with rapidly increased 4-kDa FITC-dextran intestinal permeability and correlated with TNF-α and Muc1 overexpression. Moreover, a significant association was observed between Muc1, Cldn1, Ocln, Par3 and aPKCζ expression in the T cell transfer model and between Muc13, Cldn1, Jam2, Tjp2, aPkcζ, Crb3 and Scrib expression in the DSS model. Additionally, MUC1 and MUC13 expression was upregulated in inflamed mucosa of IBD patients.

CONCLUSIONS

Aberrantly expressed MUC1 and MUC13 might be involved in intestinal barrier dysfunction upon inflammation by affecting junctional and cell polarity proteins, indicating their potential as therapeutic targets in IBD.

Bevacizumab as a potential anti-angiogenic therapy in schistosomiasis: A double-edged, but adjustable weapon

AIM

Investigating the anti-angiogenic effect of bevacizumab on chronic schistosomiasis mansoni in a trial to hinder the Schistosome-induced angiogenesis and porto-systemic shunting complications.

METHODS

The immunohistochemical expression of CD34, VEGF-R1, PCNA and α-SMA (angiogenesis markers) was analysed in the lung, liver and gastrointestinal junctions of chronic S mansoni infected mice after intraperitoneal injection of bevacizumab. The effect of prolonged administration of bevacizumab with praziquantel was also assessed through parasitic load, protective index, granuloma and fibrous tissue evaluation.

RESULTS

A regression in the vascular activity and microvascular density was observed in the infected mice after receiving bevacizumab. They had a significantly less VEGF-R1, PCNA, CD-34 and α-SMA expression in comparison to the infected untreated mice. The least tissue egg count was reported in mice received bevacizumab for 6 weeks (Mean = 27 120). However, they had persistent liver granulomas, and massively amalgamated fibrosis. Interestingly, the least faecal egg and tissue worms counts (Mean = 112, 13.4), and the highest protection index (39.26) were reported in mice received bevacizumab for 3 weeks, with marked granuloma, and fibrous tissue resolution.

CONCLUSIONS

Bevacizumab has a promising protective effect against the Schistosoma-induced angiogenesis. As an adjuvant to praziquantel, it is important to adjust the appropriate duration of administration that achieves the best schistosomicidal effect without impeding granuloma and fibrous tissue resolution.

Parasite Cystatin: Immunomodulatory Molecule with Therapeutic Activity against Immune Mediated Disorders

The use of parasites or their products for treating chronic inflammation associated diseases (CIADs) has generated significant attention recently. Findings from basic and clinical research have provided valuable information on strengthening the notion that parasites' molecules can be developed as biotherapeutic agents. Completion of the genome, secreotome, and proteome of the parasites has provided an excellent platform for screening and identifying several host immunomodulatory molecules from the parasites and evaluate their therapeutic potential for CIADs. One of the widely studied host immunomodulatory molecules of the parasites is the cysteine protease inhibitor (cystatin), which is primarily secreted by the parasites to evade host immune responses. In this review, we have attempted to summarize the findings to date on the use of helminth parasite-derived cystatin as a therapeutic agent against CIADs. Although several studies suggest a role for alternatively activated macrophages, other regulatory cells, and immunosuppressive molecules, in this immunoregulatory activity of the parasite-derived cystatin, there is still no clear demonstration as to how cystatin induces its anti-inflammatory effect in suppressing CIADs.

Contribution of the Gut Microbiota in P28GST-Mediated Anti-Inflammatory Effects: Experimental and Clinical Insights

An original immuno-regulatory strategy against inflammatory bowel diseases based on the use of 28 kDa glutathione S-transferase (P28GST), a unique schistosome protein, was recently proposed. Improvement of intestinal inflammation occurs through restoration of the immunological balance between pro-inflammatory T-helper 1 (Th1) responses and both T-helper 2 (Th2) and regulatory responses. However, detailed mechanisms explaining how P28GST prevents colitis and promotes gut homeostasis remain unknown. Considering the complex interplay between the adaptive and innate immune system and the intestinal microbiota, we raised the question of the possible role of the microbial ecosystem in the anti-inflammatory effects mediated by the helminth-derived P28GST protein. We first analyzed, by 16S rRNA sequencing, the bacterial profiles of mice fecal microbiota at several time points of the P28GST-immunomodulation period prior to trinitrobenzene sulfonic acid (TNBS)-colitis. The influence of gut microbiota in the P28GST-mediated anti-inflammatory effects was then assessed by fecal microbiota transplantation experiments from P28GST-immunized mice to either conventional or microbiota depleted naïve recipient mice. Finally, the experimental data were supplemented by the temporal fecal microbiota compositions of P28GST-treated Crohn’s disease patients from a pilot clinical study (NCT02281916). The P28GST administration slightly modulated the diversity and composition of mouse fecal microbiota while it significantly reduced experimental colitis in mice. Fecal microbiota transplantation experiments failed to restore the P28GST-induced anti-inflammatory effects. In Crohn’s disease patients, P28GST also induced slight changes in their overall fecal bacterial composition. Collectively, these results provide key elements in both the anti-inflammatory mechanisms and the safe therapeutic use of immunomodulation with such promising helminth-derived molecules.

Effect of recombinant Trichinella spiralis cysteine proteinase inhibitor on TNBS-induced experimental inflammatory bowel disease in mice

Inflammatory bowel disease (IBD) is a chronic autoimmune disease with a high recurrence rate. Ulcerative colitis (UC) and Crohn's disease (CD) are two types of IBD. At present, parasite-derived cysteine protease inhibitors have received extensive attention from researchers, and experiments have confirmed that these protease have an effect on certain autoimmune diseases. So we conducted experiments to investigate the effect of Trichinella spiralis cysteine protease inhibitors on TNBS-induced mouse CD models. In this experiment, 72 male BALB/c mice aged 6-8 weeks were randomly divided into two groups: prevention group and therapy group. The mice were sacrificed and harvested on the 7th day after the model was established to measure the changes of various indicators of colitis. The comparison of the TsCystatin + TNBS group with the PBS + TNBS group showed that the DAI score, MPO activity, and colonic macroscopic and microscopic damage significantly reduced, IFN-γ significantly decreased, IL-4 expression increased, and NF-κB expression decreased. The percentage of CD4+CD25+Foxp3+ Treg and CD8+CD28- Treg in spleen, and the proportion of CD4+/CD8+ Treg cells decreased. In the therapy group, we found no significant difference between the TNBS+PBS group and TNBS + TsCystatin group. Treatment with TsCystatin exerted a good intervention effect on the TNBS-induced mouse CD model. TsCystatin possibly induced a Th2-type immune response in the body, which balanced the Th1-type immune response induced by TNBS administration, thereby relieving colitis.

Effect of two recombinant Trichinella spiralis serine protease inhibitors on TNBS-induced experimental colitis of mice

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease (CD), is a chronic autoimmune disease. Parasitic infections and their products have been shown to have protective effects on autoimmune diseases, including IBD. In this experiment, 96 male BALB/c mice aged 6-8 weeks were divided randomly into two large groups: prevention and therapy. The changes in the various indicators of colitis were detected to demonstrate that Trichinella spiralis serine protease inhibitors can relieve the inflammatory severity of 2,4,6-trinitrobenzenesulphonic acid solution (TNBS)-induced colitis and to explore possible immunological mechanisms. Results showed that the disease activity index (DAI) score, myeloperoxidase (MPO) activity, macroscopic and microscopic damage degrees of colon all decreased significantly, interferon (IFN)-γ expression decreased, interleukin (IL)-4 expression increased, nuclear factor kappa B (NF)-κB expression decreased and the percentage of CD4⁺ CD25⁺ forkhead box protein 3 (FoxP3⁺ ) regulatory T cells (T_reg ) cells in the spleen. MLN increased significantly compared to the phosphate-buffered saline (PBS)/2,4,6-trinitrobenzenesulphonic acid solution (TNB) group. We found the same results with the T. spiralis Kazal-type serine protease inhibitors (TsKaSPI)+TNBS and TsAdSPI+TNBS groups in the large prevention group and the large therapy group, compared to the TNBS+PBS group with the TNBS+TsKaSPI and TNBS+TsAdSPI groups. Immunization with TsKaSPI and TsAdSPI on the CD models showed an intervention effect, possibly because TsKaSPI and TsAdSPI induced a T helper type 2 (Th2)-type immune response and balanced the TNBS-induced Th1-type immune response.

Acute infection with Strongyloides venezuelensis increases intestine production IL-10, reduces Th1/Th2/Th17 induction in colon and attenuates Dextran Sulfate Sodium-induced colitis in BALB/c mice

Helminth infection can reduce the severity of inflammatory bowel disease. However, the modulatory mechanisms elicited by helminth infection are not yet fully understood and vary depending on the experimental model. Herein we evaluated the effect of acute infection of BALB/c mice with Strongyloides venezuelensis on the clinical course of ulcerative colitis induced by Dextran Sulfate Sodium (DSS) treatment of these animals. For the experiments, S. venezuelensis-infected BALB/c mice were treated orally with 4% DSS solution for seven days. As controls, we used untreated S. venezuelensis infected, DSS-treated uninfected, and untreated/uninfected BALB/c mice. During DSS treatment, mice from the different groups were compared with regards to the clinical signs related to the severity of colitis and intestinal inflammation. Mice acutely infected with S. venezulensis and treated with DSS had reduced clinical score, shortening of the colon, and tissue inflammation. Moreover, DSS-treated and infected mice showed reduced IL-4, INF-γ, and IL-17 levels and increase of IL-10 production in the colon and/or in the supernatant of mesenteric lymph nodes cell cultures that resulted in lower eosinophil peroxidase and myeloperoxidase activity in colon homogenates, when compared with DSS-treated uninfected mice. DSS-treated infected mice also preserved the intestine architecture and had normal differentiation of goblet cells and mucus production in the colon mucosa. In conclusion, the data indicate that the clinical improvement reported in DSS-treated infected mice was accompanied by the lower production of Th1/Th2/Th17 pro-inflammatory cytokines, stimulation of IL-10, and induction of mucosal repair mechanisms.

Identifying Therapeutic Targets for Sepsis Research: A Characterization Study of the Inflammatory Players in the Cecal Ligation and Puncture Model

During sepsis, disturbed gastrointestinal motility and increased mucosal permeability can aggravate sepsis due to the increased risk of bacterial translocation. To help identify new therapeutic targets, there is a need for animal models that mimic the immunological changes in the gastrointestinal tract as observed during human sepsis. We therefore characterized in detail the gastrointestinal neuroimmune environment in the cecal ligation and puncture (CLP) model, which is the gold standard animal model of microbial sepsis. Mice were sacrificed at day 2 and day 7, during which gastrointestinal motility was assessed and cytokines were measured in the serum and the colon. In the spleen, lymph nodes, ileum, and colon, subsets of leukocyte populations were identified by flow cytometry. Septic animals displayed an impaired gastrointestinal motility at day 2 and day 7. Two days post-CLP, increased serum and colonic levels of proinflammatory cytokines were measured. Flow cytometry revealed an influx of neutrophils in the colon and ileum, increased numbers of macrophages in the spleen and mesenteric lymph nodes, and an enhanced number of mast cells in all tissues. At day 7 post-CLP, lymphocyte depletion was observed in all tissues coinciding with increased IL-10 and TGF-β levels, as well as increased colonic levels of IL-17A and IFN-γ. Thus, CLP-induced sepsis in mice results in simultaneous activation of pro- and anti-inflammatory players at day 2 and day 7 in different tissues, mimicking human sepsis.

Parasite-Derived Proteins for the Treatment of Allergies and Autoimmune Diseases

The morbidity associated with atopic diseases and immune dysregulation disorders such as asthma, food allergies, multiple sclerosis, atopic dermatitis, type 1 diabetes mellitus, and inflammatory bowel disease has been increasing all around the world over the past few decades. Although the roles of non-biological environmental factors and genetic factors in the etiopathology have been particularly emphasized, they do not fully explain the increase; for example, genetic factors in a population change very gradually. Epidemiological investigation has revealed that the increase also parallels a decrease in infectious diseases, especially parasitic infections. Thus, the reduced prevalence of parasitic infections may be another important reason for immune dysregulation. Parasites have co-evolved with the human immune system for a long time. Some parasite-derived immune-evasion molecules have been verified to reduce the incidence and harmfulness of atopic diseases in humans by modulating the immune response. More importantly, some parasite-derived products have been shown to inhibit the progression of inflammatory diseases and consequently alleviate their symptoms. Thus, parasites, and especially their products, may have potential applications in the treatment of autoimmune diseases. In this review, the potential of parasite-derived products and their analogs for use in the treatment of atopic diseases and immune dysregulation is summarized.

SXP-RAL Family Filarial Protein, rWbL2, Prevents Development of DSS-Induced Acute Ulcerative Colitis

Helminthic infections lead to the release of various molecules which play an important role in modulation of the host immune system. Such filarial proteins with immunomodulatory potential can be used for therapeutic purpose in inflammatory and immune mediated diseases. In the present study, we have explored the prophylactic effect of filarial SXP-RAL family protein of Wuchereria bancrofti i.e. rWbL2 protein in DSS induced inflammatory ulcerative colitis in a mouse model. Prior treatment of rWbL2, followed by induction of colitis, showed significantly reduced disease severity as indicated by the decreased disease manifestations and improved macroscopic and microscopic inflammation. This preventive effect was found to be associated with increased release of anti-inflammatory cytokine IL-10 and decreased release of proinflammatory cytokines IFN-γ, TNF-α, IL-6 and IL-17 by the splenocytes of treated mice. From this study, it can be envisaged that pretreatment with filarial protein, rWbL2, can prevent the establishment of ulcerative colitis in BALB/c mice. The underlying immunological mechanism may involve the up-regulation of Th2 immune response with down-regulation of Th1 response.

Therapeutic potential of helminths in autoimmune diseases: helminth-derived immune-regulators and immune balance

Helminths have accompanied human throughout history by releasing immune-evasion molecules that could counteract an aberrant immune response within the host. In the past decades, helminth infections are becoming less prevalent possibly due to the developed sanitation. Meanwhile, the incidence of autoimmune diseases is increasing, which cannot be exclusively explained by the changes of susceptibility genes. While the hygiene hypothesis casts light on the problem. The infections of helminths are believed to interact with and regulate human immunity with the byproduct of suppressing the autoimmune diseases. Thus, helminths are potential to treat or cure the autoimmune diseases. The therapeutic progresses and possible immune suppression mechanisms are illustrated in the review. The helminths that are studied most intensively include Heligmosomoides polygyrus, Hymenolepis diminuta, Schistosoma mansoni, Trichinella spiralis, and Trichuris suis. Special attentions are paid on the booming animal models and clinical trials that are to detect the efficiency of immune-modulating helminth-derived molecules on autoimmune diseases. These trials provide us with a prosperous clinical perspective, but the precise mechanism of the down-regulatory immune response remains to be clarified. More efforts are needed to be dedicated until these parasite-derived immune modulators could be used in clinic to treat or cure the autoimmune diseases under a standard management.

Helminths in the gastrointestinal tract as modulators of immunity and pathology

Helminth parasites are highly prevalent in many low- and middle-income countries, in which inflammatory bowel disease and other immunopathologies are less frequent than in the developed world. Many of the most common helminths establish themselves in the gastrointestinal tract and can exert counter-inflammatory influences on the host immune system. For these reasons, interest has arisen as to how parasites may ameliorate intestinal inflammation and whether these organisms, or products they release, could offer future therapies for immune disorders. In this review, we discuss interactions between helminth parasites and the mucosal immune system, as well as the progress being made toward identifying mechanisms and molecular mediators through which it may be possible to attenuate pathology in the intestinal tract.

Helminth Regulation of Immunity: A Three-pronged Approach to Treat Colitis

By reputation, the parasite is a pariah, an unwelcome guest. Infection with helminth parasites evokes stereotypic immune responses in humans and mice that are dominated by T helper (Th)-2 responses; thus, a hypothesis arises that infection with helminths would limit immunopathology in concomitant inflammatory disease. Although infection with some species of helminths can cause devastating disease and affect the course of microbial infections, analyses of rodent models of inflammatory disease reveal that infection with helminth parasites, or treatment with helminth extracts, can limit the severity of autoinflammatory disease, including colitis. Intriguing, but fewer, studies show that adoptive transfer of myeloid immune cells treated with helminth products/extracts in vitro can suppress inflammation. Herein, 3 facets of helminth therapy are reviewed and critiqued: treatment with viable ova or larvae, treatment with crude extracts of the worm or purified molecules, and cellular immunotherapy. The beneficial effect of helminth therapy often converges on the mobilization of IL-10 and regulatory/alternatively activated macrophages, while there are reports on transforming growth factor (TGF)-β, regulatory T cells and dendritic cells, and recent data suggest that helminth-evoked changes in the microbiota should be considered when defining anticolitic mechanisms. We speculate that if the data from animal models translate to humans, noting the heterogeneity therein, then the choice between use of viable helminth ova, helminth extracts/molecules or antigen-pulsed immune cells could be matched to disease management in defined cohorts of patients with inflammatory bowel disease.

Schistosome-Derived Molecules as Modulating Actors of the Immune System and Promising Candidates to Treat Autoimmune and Inflammatory Diseases

It is long known that some parasite infections are able to modulate specific pathways of host's metabolism and immune responses. This modulation is not only important in order to understand the host-pathogen interactions and to develop treatments against the parasites themselves but also important in the development of treatments against autoimmune and inflammatory diseases. Throughout the life cycle of schistosomes the mammalian hosts are exposed to several biomolecules that are excreted/secreted from the parasite infective stage, named cercariae, from their tegument, present in adult and larval stages, and finally from their eggs. These molecules can induce the activation and modulation of innate and adaptive responses as well as enabling the evasion of the parasite from host defense mechanisms. Immunomodulatory effects of helminth infections and egg molecules are clear, as well as their ability to downregulate proinflammatory cytokines, upregulate anti-inflammatory cytokines, and drive a Th2 type of immune response. We believe that schistosomes can be used as a model to understand the potential applications of helminths and helminth-derived molecules against autoimmune and inflammatory diseases.

Therapeutic potential of recombinant cystatin from Schistosoma japonicum in TNBS-induced experimental colitis of mice

Background

Helminth infections and their components have been shown to have a protective effect on autoimmune diseases. The isolated purified protein from Schisotosoma japonicum and its potential therapeutic effect on trinitrobenzene sulfonic acid (TNBS)-induced colitis could provide an alternative way to treat inflammatory bowel disease (IBDs).

Methods

Colitis was induced in Balb/c mice by rectal administration of 2.5 % TNBS, followed by intraperitoneal injection of rSjcystatin 50 μg at 6 h and 24 h afterwards. The inflammation was monitored by recording weight change, stool character and bleeding, colon length, macroscopic score (MAO), microscopic score (MIO), myeloperoxidase activity (MPO) and disease activity index (DAI). The potential underlying mechanism was investigated by examining cytokine profiles including Th1 (IFNγ), Th2 (IL-4), Th17 (IL-17A) and Treg subsets from lymphocytes of spleen, mesenteric lymph nodes (MLN) and intestinal lamina propria mononuclear cells (LPMCs) by flow cytometry. The mRNA relative expressions of the cytokines in splenocytes and MLN were analysed by quantitative real time reverse-transcriptase polymerase chain reaction (qRT-PCR). Simultaneously, the concentrations of the cytokines in the colon homogenate supernatants were tested by enzyme-linked immunosorbent assay (ELISA) and key transcription factors were detected by Western blotting.

Results

Administration of rSjcystatin significantly reduced inflammatory parameters and ameliorated the severity of the TNBS-induced colitis through decreasing IFNγ in three organs and lifting the level of IL-4, IL-13, IL-10, and TGF-β in the colon tissues, with uptrending Tregs in the MLN and LPMC.

Conclusion

The findings provide evidence that rSjcystatin has a therapeutic potential for diminishing colitis inflammation in Balb/c mice. The immunological mechanism may involve the down-regulation of Th1 response and up-regulation of Th2 and Tregs in the MLN and colon.

Helminth therapy for organic diseases?

Autoimmune and chronic inflammatory organic diseases represent a "postindustrial revolution epidemics," and their frequency has increased dramatically in the last century. Today, it is assumed that the increase in hygiene standards reduced the interactions with helminth parasites that coevolved with the immune system and are crucial for its proper functioning. Several helminths have been proposed and tested in the search of the ideal therapeutic. In this review, the authors summarize the translational and clinical studies and review the caveats and possible solutions for the optimization of helminth therapies.

Effect of schistosomiasis on CX3CR1-expressing mononuclear phagocytes in the ileum and mesenteric lymph nodes of the mouse

BACKGROUND

Intestinal dendritic cells (DCs) maintain immune homeostasis, only initiating an active immune response against invading pathogens. However, little information is available on the reaction of mononuclear phagocytes (MNP) to intestinal trematode infection, a reaction equally important in helminth-based therapies. The CD11c(+)  CX3CR1(+)  F4/80(-) DCs in the ileal lamina propria (LP) of the mouse were proven to migrate to the mesenteric lymph nodes (MLNs). We analyzed all MNP subsets present in the mouse LP and MLNs, under steady-state conditions and during acute Schistosoma mansoni-induced inflammation. Furthermore, we studied the uptake of schistosomal antigens by MNP in vivo in the LP and MLNs.

METHODS

Using a combination of immunohistochemistry and multiparametric flow cytometry, we investigated distributional changes of the MNP during acute intestinal schistosomiasis. Next, S. mansoni-derived products, i.e., S. mansoni soluble worm proteins (SmSWP) and S. mansoni soluble egg antigens (SmSEA) were intraperitoneally injected into CX3CR1(+/) (GFP) C57BL/6 mice and antigen uptake was analyzed using confocal microscopy.

KEY RESULTS

The CD11c(+)  CX3CR1(+)  F4/80(-) DCs significantly increased during intestinal schistosomiasis in the LP and MLNs. Only CX3CR1-expressing DC and MФ subsets, but not other LP DCs, are involved in both SmSWP and SmSEA antigen uptake and processing.

CONCLUSIONS & INFERENCES

The significant upregulation of CD11c(+)  CX3CR1(+)  F4/80(-) DCs during intestinal schistosomiasis and the restriction of phagocytosis of parasitic antigens to CX3CR1-expresssing MNP indicate a crucial role for this immune cell niche in response to trematodiasis. These findings add insight into the functional specialization of LP immune cells and add to the understanding of cellular mechanisms behind helminth-based therapies.

Role of type 2 immunity in intestinal inflammation

PURPOSE OF REVIEW

Type 2 (Th2) immune responses play important roles in intestinal immunity by contributing to the maintenance of mucosal homeostasis, not only conferring protection against helminthic infection but also participating in pro-inflammatory pathways in chronic intestinal inflammatory disorders, including inflammatory bowel disease. The current review focuses on recent developments regarding the role of Th2 responses in intestinal inflammation.

RECENT FINDINGS

Th2 gut mucosal responses are promoted by mediators that are released following injury to the epithelium, and act as alarmin-type danger signals. Interleukin (IL)-33 is prominent among such factors and demonstrates a dichotomous function, exerting either protective or pro-inflammatory effects, depending on its cellular compartmentalization. The pool of type 2 effector cells has been enriched recently to include not only classical CD4+ Th2 lymphocytes but also a subset of innate lymphocytes (ILC2s) that express the transcriptional factor GATA binding protein 3 and secrete IL-4, IL-5, and IL-13. ILC2s play important roles during infection with helminths and bi-directionally interact with Th2 CD4+ lymphocytes, thus establishing a transition from innate to adaptive immunological pathways. Th2 responses are also involved in pro-inflammatory pathways at the intestinal mucosa, and neutralization of the pivotal cytokines IL-4 and IL-13 has been shown to regulate experimental intestinal inflammation. In striking contrast, however, neutralization of human IL-13 had no therapeutic effect in patients with ulcerative colitis.

SUMMARY

Further studies will be required to delineate the specific mechanisms of type 2 mucosal immunity in inflammatory bowel disease and examine the applicability of Th2-targeted therapies for intestinal inflammation.

Brugia malayi cystatin therapeutically ameliorates dextran sulfate sodium-induced colitis in mice

OBJECTIVE

Helminth immunomodulation in the host has been shown to have therapeutic implications in inflammatory bowel diseases. In this study we aimed to evaluate the therapeutic effect of Brugia malayi recombinant cystatin (rBmCys) in a dose-dependent manner on dextran sulfate sodium (DSS)-induced colitis in mice.

METHODS

The anti-inflammatory activity of rBmCys on mice peritoneal exudate cells was initially analyzed in vitro. BALB/c mice were fed with 5% DSS for 7 days to induce colitis. The colitis mice were treated intraperitoneally with rBmCys (10, 25 or 50 µg for the three different groups of mice) on days 1, 3 and 5 of the DSS administration. Disease severity was assessed by the disease activity index (DAI) and macroscopic and histopathological scores of colon and myeloperoxidase activity in colonic mucosa. Cytokine profiles were measured in sera and cultured splenocytes of treated mice followed by stimulation with rBmCys.

RESULTS

rBmCys showed anti-inflammatory activity in vitro. Treatment of DSS-induced colitis with rBmCys in mice ameliorated the overall disease severity as reflected by a significant reduction in weight loss, the DAI, mucosal edema, colon damage and myeloperoxidase activity of the colonic mucosa. While the mRNA expressions of IFN-γ, TNF-α, interleukin (IL)-5, IL-6 and IL-17 were downregulated, IL-10 expression was upregulated in the splenocytes of colitis mice treated with rBmCys. The amelioration of DSS-induced colitis occurred in a dose-dependent manner.

CONCLUSION

The results of this study indicate an anti-inflammatory potential of rBmCys and provide evidence for using this protein as a promising therapeutic agent in ulcerative colitis.