The Worm-Specific Immune Response in Multiple Sclerosis Patients Receiving Controlled Trichuris suis Ova Immunotherapy

The rebalancing of the immune system at the maternal-fetal interface ameliorates autism-like behavior in adult offspring

Maternal immune activation (MIA) is critical for imparting neuropathology and altered behaviors in offspring; however, maternal-fetal immune cell populations have not been thoroughly investigated in MIA-induced autism spectrum disorders (ASDs). Here, we report the single-cell transcriptional landscape of placental cells in both PBS- and poly(I:C)-induced MIA dams. We observed a decrease in regulatory T (Treg) cells but an increase in the M1 macrophage population at the maternal-fetal interface in MIA dams. Based on the Treg-targeting approach, we investigate an immunoregulatory protein, the helminth-derived heat shock protein 90α (Sjp90α), that induces maternal Treg cells and subsequently rescues the autism-like behaviors in adult offspring. Furthermore, in vivo depletion of maternal macrophages attenuates placental inflammatory reaction and reverses behavioral abnormalities in adult offspring. Notably, Sjp90α induces CD4+ T cell differentiation via scavenger receptor A (SR-A) on the macrophage in vitro. Our findings suggest a maternal Treg-targeted approach to alleviate MIA-induced autism-like behavior in adult offspring.

CsHscB Derived from a Liver Fluke Clonorchis sinensis Ameliorates Cholestatic Hepatic Fibrosis in a Mouse Model of Sclerosing Cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammatory fibrosis usually involving the whole biliary tree. However, there are very limited treatment options to treat this disease. Our previous study found a lipid-protein rCsHscB from a liver fluke - Clonorchis sinensis, which had full capacities of immune regulation. Therefore, we investigated the role of rCsHscB in a mouse model of sclerosing cholangitis induced by xenobiotic 3,5- diethoxycarbonyl-1,4-dihydrocollidine (DDC) to explore whether this protein had potential therapeutic value for PSC.

METHODS

Mice were fed 0.1% DDC for 4 weeks and treated with CsHscB (30 μg/mouse, intraperitoneal injection, once every 3 days); the control group was given an equal amount of PBS or CsHscB under normal diet conditions. All the mice were sacrificed at 4 weeks for the evaluation of biliary proliferation, fibrosis, and inflammation.

RESULTS

rCsHscB treatment attenuated DDC-induced liver congestion and enlargement and significantly decreased the upregulation of serum AST and ALT levels. The administration of rCsHscB to DDC-fed mice significantly decreased cholangiocyte proliferation and pro-inflammatory cytokine production compared to mice fed with DDC alone. Also, rCsHscB treatment showed a decreased expression of α-SMA in the liver and other markers of liver fibrosis (Masson staining, Hydroxyproline content, and collagen deposit). More interestingly, DDC-fed mice treated with rCsHscB showed a significant up-regulation of PPAR-γ expression, which was similar to control mice, indicating the involvement of PPAR-γ signaling in the protective action of rCsHscB.

CONCLUSION

Overall, our data show that rCsHscB attenuates the progression of cholestatic fibrosis induced by DDC and supports the potential for manipulating the parasite-derived molecule to treat certain immune-mediated disorders.

Helminth Lessons in Inflammatory Bowel Diseases (IBD)

Helminths are multicellular invertebrates that colonize the gut of many vertebrate animals including humans. This colonization can result in pathology, which requires treatment. It can also lead to a commensal and possibly even a symbiotic relationship where the helminth and the host benefit from each other's presence. Epidemiological data have linked helminth exposure to protection from immune disorders that include a wide range of diseases, such as allergies, autoimmune illnesses, and idiopathic inflammatory disorders of the gut, which are grouped as inflammatory bowel diseases (IBD). Treatment of moderate to severe IBD involves the use of immune modulators and biologics, which can cause life-threatening complications. In this setting, their safety profile makes helminths or helminth products attractive as novel therapeutic approaches to treat IBD or other immune disorders. Helminths stimulate T helper-2 (Th2) and immune regulatory pathways, which are targeted in IBD treatment. Epidemiological explorations, basic science studies, and clinical research on helminths can lead to the development of safe, potent, and novel therapeutic approaches to prevent or treat IBD in addition to other immune disorders.

A Helminth-Derived Chitinase Structurally Similar to Mammalian Chitinase Displays Immunomodulatory Properties in Inflammatory Lung Disease

Immunomodulation of airway hyperreactivity by excretory-secretory (ES) products of the first larval stage (L1) of the gastrointestinal nematode Trichuris suis is reported by us and others. Here, we aimed to identify the proteins accounting for the modulatory effects of the T. suis L1 ES proteins and studied six selected T. suis L1 proteins for their immunomodulatory efficacy in a murine OVA-induced allergic airway disease model. In particular, an enzymatically active T. suis chitinase mediated amelioration of clinical signs of airway hyperreactivity, primarily associated with suppression of eosinophil recruitment into the lung, the associated chemokines, and increased numbers of RELMα⁺ interstitial lung macrophages. While there is no indication of T. suis chitinase directly interfering with dendritic cell activation or antigen presentation to CD4 T cells, treatment of allergic mice with the worm chitinase influenced the hosts' own chitinase activity in the inflamed lung. The three-dimensional structure of the T. suis chitinase as determined by high-resolution X-ray crystallography revealed high similarities to mouse acidic mammalian chitinase (AMCase) but a unique ability of T. suis chitinase to form dimers. Our data indicate that the structural similarities between the parasite and host chitinase contribute to the disease-ameliorating effect of the helminth-derived chitinase on allergic lung inflammation.

Un-‘Egg’-Plored: Characterisation of Embryonation in the Whipworm Model Organism Trichuris muris

Trichuris muris, is the murine parasite and widely deployed model for the human whipworm Trichuris trichiura, a parasite that infects around 500 million people globally. Trichuriasis is a classical disease of poverty with a cycle of re-infection due to the continual exposure of humans, particularly children, to infective eggs, which contaminate the soil in endemic areas. Indeed, modelling studies of trichuriasis have demonstrated that the low efficacy rate of current anthelmintics combined with the high possibility of re-infection from the reservoir of infective eggs within the environment, mean that the elimination of morbidity due to trichuriasis is unlikely to occur. Despite the importance of the infective egg stage in the perpetuation of infections, understanding the biology of the Trichuris ova has been neglected for decades. Here we perform experiments to assess the impact of temperature on the embryonation process of T. muris eggs and describe in detail the stages of larval development within these eggs. In keeping with the early works performed in the early 1900s, we show that the embryonation of T. muris is accelerated by an elevation in temperature, up to 37°C above which eggs do not fully develop and become degenerate. We extend these data to provide a detailed description of T. muris egg development with clear images depicting the various stages of development. To the best of our knowledge we have, for the first time, described the presence of birefringent granules within egg-stage larvae, as well as providing a qualitative and quantitative description of a motile larval stage prior to quiescence within the egg. These experiments are the first step towards a better understanding of the basic biology which underlies the process of egg embryonation. With the threat of elevation in global temperatures, the accelerated embryonation rate we observe at higher temperatures may have important consequences for parasite transmission rates and prospective modelling studies. In addition, a deeper understanding of the Trichuris ova may allow the development of novel control strategies targeting the egg stage of Trichuris in the environment as an adjunct to MDA.

Crosstalk of Microorganisms and Immune Responses in Autoimmune Neuroinflammation: A Focus on Regulatory T Cells

Regulatory T cells (Tregs) are the major determinant of peripheral immune tolerance. Many Treg subsets have been described, however thymus-derived and peripherally induced Tregs remain the most important subpopulations. In multiple sclerosis, a prototypical autoimmune disorder of the central nervous system, Treg dysfunction is a pathogenic hallmark. In contrast, induction of Treg proliferation and enhancement of their function are central immune evasion mechanisms of infectious pathogens. In accordance, Treg expansion is compartmentalized to tissues with high viral replication and prolonged in chronic infections. In friend retrovirus infection, Treg expansion is mainly based on excessive interleukin-2 production by infected effector T cells. Moreover, pathogens seem also to enhance Treg functions as shown in human immunodeficiency virus infection, where Tregs express higher levels of effector molecules such as cytotoxic T-lymphocyte-associated protein 4, CD39 and cAMP and show increased suppressive capacity. Thus, insights into the molecular mechanisms by which intracellular pathogens alter Treg functions might aid to find new therapeutic approaches to target central nervous system autoimmunity. In this review, we summarize the current knowledge of the role of pathogens for Treg function in the context of autoimmune neuroinflammation. We discuss the mechanistic implications for future therapies and provide an outlook for new research directions.

Infection with Hymenolepis diminuta Blocks Colitis and Hastens Recovery While Colitis Has Minimal Impact on Expulsion of the Cestode from the Mouse Host

Two experimental paradigms were adopted to explore host-helminth interactions involved in the regulation of colitis and to understand if colitis affects the outcome of helminth infection. First, male BALB/c mice infected with H. diminuta were challenged 4 days later with dinitrobenzene sulphonic acid (DNBS) and necropsied 3 days later. Second, mice were infected with H. diminuta 3 days after DNBS treatment and necropsied 11 or 14 days post-DNBS. Mice were assessed for colitic disease severity and infectivity with H. diminuta upon necropsy. Supporting the concept of helminth therapy, mice are protected from DNBS-colitis when infected with H. diminuta only 4 days previously, along with parallel increases in splenic production of Th2 cytokines. In the treatment regimen, H. diminuta infection produced a subtle, statistically significant, enhanced recovery from DNBS. Mice regained body weight quicker, had normalized colon lengths, and showed no overt signs of disease, in comparison to the DNBS-only mice, some of which displayed signs of mild disease at 14 days post-DNBS. Unexpectedly, colitis did not affect the hosts' anti-worm response. The impact of inflammatory disease on helminth infection is deserving of study in a variety of models as auto-inflammatory diseases emerge in world regions where parasitic helminths are endemic.

The interplay between Trichuris and the microbiota

Parasitic worms are amongst the most common pathogens to infect humans and have a long-established history of inflicting disease in their hosts. There is a large body of evidence that states intestine-dwelling helminths ensure their survival by influencing the host immune response against them. In recent years, it has become apparent that the large and diverse microbial communities that exist in the gastrointestinal (GI) tract of the host and within the parasite itself have a pivotal role in worm survival and persistence. Using a variety of mouse models (including laboratory, germ-free and rewilded mice), there have been new insights into how bacteria and worms interact with each other; this includes the discovery that Trichuris is unable to hatch and/or infect their host in the absence of bacteria, and that these worms contain a Trichuris-specific gut microbiota. These interactions are determined in part by the capacity of the host, gut microbiota and worms to communicate via metabolites such as butyrate, which are microbially derived and have known immunoregulatory properties. By exploring the contribution of gut bacteria to worm infections and the intricate relationship that exists between them, an exciting and emerging field in whipworm parasitology is established.