Small Molecule Analogues of the parasitic worm product ES-62 interact with the TIR domain of MyD88 to inhibit pro-inflammatory signalling

Anti-Inflammatory Effects of Helminth-Derived Products: Potential Applications and Challenges in Diabetes Mellitus Management

The global rise in diabetes mellitus (DM), particularly type 2 diabetes (T2D), has become a major public health challenge. According to the "hygiene hypothesis", helminth infections may offer therapeutic benefits for DM. These infections are known to modulate immune responses, reduce inflammation, and improve insulin sensitivity. However, they also carry risks, such as malnutrition, anemia, and intestinal obstruction. Importantly, helminth excretory/secretory products, which include small molecules and proteins, have shown therapeutic potential in treating various inflammatory diseases with minimal side effects. This review explores the anti-inflammatory properties of helminth derivatives and their potential to alleviate chronic inflammation in both type 1 diabetes and T2D, highlighting their promise as future drug candidates. Additionally, it discusses the possible applications of these derivatives in DM management and the challenges involved in translating these findings into clinical practice.

Targeting Myeloid Differentiation Primary Response Protein 88 (MyD88) and Galectin-3 to Develop Broad-Spectrum Host-Mediated Therapeutics against SARS-CoV-2

Nearly six million people worldwide have died from the coronavirus disease (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although COVID-19 vaccines are largely successful in reducing the severity of the disease and deaths, the decline in vaccine-induced immunity over time and the continuing emergence of new viral variants or mutations underscore the need for an alternative strategy for developing broad-spectrum host-mediated therapeutics against SARS-CoV-2. A key feature of severe COVID-19 is dysregulated innate immune signaling, culminating in a high expression of numerous pro-inflammatory cytokines and chemokines and a lack of antiviral interferons (IFNs), particularly type I (alpha and beta) and type III (lambda). As a natural host defense, the myeloid differentiation primary response protein, MyD88, plays pivotal roles in innate and acquired immune responses via the signal transduction pathways of Toll-like receptors (TLRs), a type of pathogen recognition receptors (PRRs). However, recent studies have highlighted that infection with viruses upregulates MyD88 expression and impairs the host antiviral response by negatively regulating type I IFN. Galectin-3 (Gal3), another key player in viral infections, has been shown to modulate the host immune response by regulating viral entry and activating TLRs, the NLRP3 inflammasome, and NF-κB, resulting in the release of pro-inflammatory cytokines and contributing to the overall inflammatory response, the so-called "cytokine storm". These studies suggest that the specific inhibition of MyD88 and Gal3 could be a promising therapy for COVID-19. This review presents future directions for MyD88- and Gal3-targeted antiviral drug discovery, highlighting the potential to restore host immunity in SARS-CoV-2 infections.

The allure of targets for novel drugs

The challenges of bringing new medicines to patients have been extensively discussed and debated, including consideration of the contribution that academic laboratories can make. At the University of Strathclyde, drug discovery has been a continuing focal activity since the 1960s, and in the past 30 years, the author has led or contributed to many projects of different character and for diverse diseases. A feature common to these projects is the extension of concepts of molecular and biological targets in drug discovery research. In mechanistic terms, these have included compounds that are activators and not inhibitors, and in particular multitargeted compounds. With respect to relevance to disease, schizophrenia, pulmonary disfunction, autoimmune, and infectious disease are most relevant. These projects are discussed in the context of classical medicinal chemistry and more recent concepts in and approaches to drug discovery.

Reduction in creatine metabolites in macrophages exposed to small molecule analogues of the anti-inflammatory parasitic worm product ES-62

ES-62, a protein secreted by Acanthocheilonema viteae, is anti-inflammatory by virtue of covalently attached phosphorylcholine (PC) residues and thus a library of drug-like small molecule analogues (SMAs) based on its PC moieties has been designed for therapeutic purposes. Two members, SMAs 11a and 12b, were previously found to suppress production of pro-inflammatory cytokines by mouse bone marrow-derived macrophages (BMMs) exposed to cytosine-phosphate-guanosine oligodeoxynucleotides (CpG), agonists for Toll-like receptor 9. In order to explore the mechanism of action underlying such activities, an untargeted mass spectrometry-based metabolomics screen was undertaken. Stimulation of BMMs with CpG produced significant metabolic changes relating to glycolysis and the TCA cycle but the SMAs had little impact on this. Also, the SMAs did not promote alterations in metabolites known to be associated with macrophage M1/M2 polarization. Rather, BMMs exposed to SMAs 11a or 12b prior to CpG treatment, or even alone, revealed downregulation of metabolites of creatine, a molecule whose major role is in the transport of high energy phosphate from the mitochondria to the cytosol. These data therefore provide insight into a possible mechanism of action of molecules with significant therapeutic potential that has not previously been described for parasitic worm products.

Protection against lung pathology during obesity-accelerated ageing in mice by the parasitic worm product ES-62

Mice develop pathology in the lungs as they age and this may be accelerated by a high calorie diet (HCD). ES-62 is a protein secreted by the parasitic worm Acanthocheilonema viteae that is immunomodulatory by virtue of covalently attached phosphorylcholine (PC) moieties. In this study, we show that weekly treatment of C57BL/6J mice with ES-62 protected against pathology in the lungs in male but not female mice fed a HCD from 10 weeks of age as shown by reductions in cellular infiltration and airway remodelling, particularly up to 160 days of age. ES-62 also reduced gene expression of the cytokines IL-4 and IL-17 and in addition the TLR/IL-1R adaptor MyD88, in the lungs of male mice although HCD-induced increases in these inflammatory markers were not detected until between 340 and 500 days of age. A combination of two drug-like ES-62 PC-based small molecule analogues (SMAs), produced broadly similar protective effects in the lungs of male mice with respect to both lung pathology and inflammatory markers, in addition to a decrease in HCD-induced IL-5 expression. Overall, our data show that ES-62 and its SMAs offer protection against HCD-accelerated pathological changes in the lungs during ageing. Given the targeting of Th2 cytokines and IL-17, we discuss this protection in the context of ES-62's previously described amelioration of airway hyper-responsiveness in mouse models of asthma.

The biosynthesis and role of phosphorylcholine in pathogenic and nonpathogenic bacteria

Phosphorylcholine (ChoP) can be found in all life forms. Although this molecule was first thought to be uncommon in bacteria, it is now appreciated that many bacteria express ChoP on their surface. ChoP is usually attached to a glycan structure, but in some cases, it is added as a post-translational modification to proteins. Recent findings have demonstrated the role of ChoP modification and phase variation (ON/OFF switching) in bacterial pathogenesis. However, the mechanisms of ChoP synthesis are still unclear in some bacteria. Here, we review the literature and examine the recent developments in ChoP-modified proteins and glycolipids and of ChoP biosynthetic pathways. We discuss how the well-studied Lic1 pathway exclusively mediates ChoP attachment to glycans but not to proteins. Finally, we provide a review of the role of ChoP in bacterial pathobiology and the role of ChoP in modulating the immune response.

The parasitic worm product ES-62 protects the osteoimmunology axis in a mouse model of obesity-accelerated ageing

Despite significant increases in human lifespan over the last century, adoption of high calorie diets (HCD) has driven global increases in type-2 diabetes, obesity and cardiovascular disease, disorders precluding corresponding improvements in healthspan. Reflecting that such conditions are associated with chronic systemic inflammation, evidence is emerging that infection with parasitic helminths might protect against obesity-accelerated ageing, by virtue of their evolution of survival-promoting anti-inflammatory molecules. Indeed, ES-62, an anti-inflammatory secreted product of the filarial nematode Acanthocheilonema viteae, improves the healthspan of both male and female C57BL/6J mice undergoing obesity-accelerated ageing and also extends median lifespan in male animals, by positively impacting on inflammatory, adipose metabolic and gut microbiome parameters of ageing. We therefore explored whether ES-62 affects the osteoimmunology axis that integrates environmental signals, such as diet and the gut microbiome to homeostatically regulate haematopoiesis and training of immune responses, which become dysregulated during (obesity-accelerated) ageing. Of note, we find sexual dimorphisms in the decline in bone health, and associated dysregulation of haematopoiesis and consequent peripheral immune responses, during obesity-accelerated ageing, highlighting the importance of developing sex-specific anti-ageing strategies. Related to this, ES-62 protects trabecular bone structure, maintaining bone marrow (BM) niches that counter the ageing-associated decline in haematopoietic stem cell (HSC) functionality highlighted by a bias towards myeloid lineages, in male but not female, HCD-fed mice. This is evidenced by the ability of ES-62 to suppress the adipocyte and megakaryocyte bias and correspondingly promote increases in B lymphocytes in the BM. Furthermore, the consequent prevention of ageing-associated myeloid/lymphoid skewing is associated with reduced accumulation of inflammatory CD11c+ macrophages and IL-1β in adipose tissue, disrupting the perpetuation of inflammation-driven dysregulation of haematopoiesis during obesity-accelerated ageing in male HCD-fed mice. Finally, we report the ability of small drug-like molecule analogues of ES-62 to mimic some of its key actions, particularly in strongly protecting trabecular bone structure, highlighting the translational potential of these studies.

Mini Review: Structure and Function of Nematode Phosphorylcholine-Containing Glycoconjugates

An unusual aspect of the biology of nematodes is the covalent attachment of phosphorylcholine (PC) to carbohydrate in glycoconjugates. Investigation of the structure of these molecules by ever-increasingly sophisticated analytical procedures has revealed that PC is generally in phosphodiester linkage with C6 of N-acetylglucosamine (GlcNAc) in both N-type glycans and glycosphingolipids. Up to five PC groups have been detected in the former, being located on both antenna and core GlcNAc. The PC donor for transfer to carbohydrate appears to be phosphatidylcholine but the enzyme responsible for transfer remains to be identified. Work primarily involving the PC-containing Acanthocheilonema viteae secreted product ES-62, has shown that the PC attached to nematode N-glycans possesses a range of immunomodulatory properties, subverting for example, pro-inflammatory signalling in various immune system cell-types including lymphocytes, mast cells, dendritic cells and macrophages. This has led to the generation of PC-based ES-62 small molecule analogues (SMAs), which mirror the parent molecule in preventing the initiation or progression of disease in mouse models of a number of human conditions associated with aberrant inflammatory responses. These include rheumatoid arthritis, systemic lupus erythematosus and lung and skin allergy such that the SMAs are considered to have widespread therapeutic potential.

Epigenetic drug development for autoimmune and inflammatory diseases

ES-62 is the major secreted protein of the parasitic filarial nematode, Acanthocheilonema viteae. The molecule exists as a large tetramer (MW, ~240kD), which possesses immunomodulatory properties by virtue of multiple phosphorylcholine (PC) moieties attached to N-type glycans. By suppressing inflammatory immune responses, ES-62 can prevent disease development in certain mouse models of allergic and autoimmune conditions, including joint pathology in collagen-induced arthritis (CIA), a model of rheumatoid arthritis (RA). Such protection is associated with functional suppression of "pathogenic" hyper-responsive synovial fibroblasts (SFs), which exhibit an aggressive inflammatory and bone-damaging phenotype induced by their epigenetic rewiring in response to the inflammatory microenvironment of the arthritic joint. Critically, exposure to ES-62 in vivo induces a stably-imprinted CIA-SF phenotype that exhibits functional responses more typical of healthy, Naïve-SFs. Consistent with this, ES-62 "rewiring" of SFs away from the hyper-responsive phenotype is associated with suppression of ERK activation, STAT3 activation and miR-155 upregulation, signals widely associated with SF pathogenesis. Surprisingly however, DNA methylome analysis of Naïve-, CIA- and ES-62-CIA-SF cohorts reveals that rather than simply preventing pathogenic rewiring of SFs, ES-62 induces further changes in DNA methylation under the inflammatory conditions pertaining in the inflamed joint, including targeting genes associated with ciliogenesis, to programme a novel "resolving" CIA-SF phenotype. In addition to introducing a previously unsuspected aspect of ES-62's mechanism of action, such unique behaviour signposts the potential for developing DNA methylation signatures predictive of pathogenesis and its resolution and hence, candidate mechanisms by which novel therapeutic interventions could prevent SFs from perpetuating joint inflammation and destruction in RA. Pertinent to these translational aspects of ES-62-behavior, small molecule analogues (SMAs) based on ES-62's active PC-moieties mimic the rewiring of SFs as well as the protection against joint disease in CIA afforded by the parasitic worm product.

Mining nematode protein secretomes to explain lifestyle and host specificity

Parasitic nematodes are highly successful pathogens, inflicting disease on humans, animals and plants. Despite great differences in their life cycles, host preference and transmission modes, these parasites share a common capacity to manipulate their host's immune system. This is at least partly achieved through the release of excretory/secretory proteins, the most well-characterized component of nematode secretomes, that are comprised of functionally diverse molecules. In this work, we analyzed published protein secretomes of parasitic nematodes to identify common patterns as well as species-specific traits. The 20 selected organisms span 4 nematode clades, including plant pathogens, animal parasites, and the free-living species Caenorhabditis elegans. Transthyretin-like proteins were the only component common to all adult secretomes; many other protein classes overlapped across multiple datasets. The glycolytic enzymes aldolase and enolase were present in all parasitic species, but missing from C. elegans. Secretomes from larval stages showed less overlap between species. Although comparison of secretome composition across species and life-cycle stages is challenged by the use of different methods and depths of sequencing among studies, our workflow enabled the identification of conserved protein families and pinpointed elements that may have evolved as to enable parasitism. This strategy, extended to more secretomes, may be exploited to prioritize therapeutic targets in the future.

Mining Helminths for Novel Therapeutics

Helminths are an emerging source of therapeutics for dysregulated inflammatory diseases. Excretory/secretory (ES) molecules, released during infection, are responsible for many of these immunomodulatory effects and are likely to have evolved as a means for parasite survival in the host. While the mechanisms of action of these molecules have not been fully defined, evidence demonstrates that they target various pathways in the immune response, ranging from initiation to effector cell modulation. These molecules are applied in controlling specific effector mechanisms of type 1 and type 2 immune responses. Recently, studies have further focused on their therapeutic potential in specific disease models. Here we review recent findings on ES molecule modulation of immune functions, specifically highlighting their clinical implications for future use in inflammatory disease therapeutics.

MyD88 and beyond: a perspective on MyD88-targeted therapeutic approach for modulation of host immunity

The continuous emergence of infectious pathogens along with antimicrobial resistance creates a need for an alternative approach to treat infectious diseases. Targeting host factor(s) which are critically involved in immune signaling pathways for modulation of host immunity offers to treat a broad range of infectious diseases. Upon pathogen-associated ligands binding to the Toll-like/ IL-1R family, and other cellular receptors, followed by recruitment of intracellular signaling adaptor proteins, primarily MyD88, trigger the innate immune responses. But activation of host innate immunity strongly depends on the correct function of MyD88 which is tightly regulated. Dysregulation of MyD88 may cause an imbalance that culminates to a wide range of inflammation-associated syndromes and diseases. Furthermore, recent reports also describe that MyD88 upregulation with many viral infections is linked to decreased antiviral type I IFN response, and MyD88-deficient mice showed an increase in survivability. These reports suggest that MyD88 is also negatively involved via MyD88-independent pathways of immune signaling for antiviral type I IFN response. Because of its expanding role in controlling host immune signaling pathways, MyD88 has been recognized as a potential drug target in a broader drug discovery paradigm. Targeting BB-loop of MyD88, small molecule inhibitors were designed by structure-based approach which by blocking TIR-TIR domain homo-dimerization have shown promising therapeutic efficacy in attenuating MyD88-mediated inflammatory impact, and increased antiviral type I IFN response in experimental mouse model of diseases. In this review, we highlight the reports on MyD88-linked immune response and MyD88-targeted therapeutic approach with underlying mechanisms for controlling inflammation and antiviral type I IFN response. HIGHLIGHTS: • Host innate immunity is activated upon PAMPs binding to PRRs followed by immune signaling through TIR domain-containing adaptor proteins mainly MyD88. • Structure-based approach led to develop small-molecule inhibitors which block TIR domain homodimerization of MyD88 and showed therapeutic efficacy in limiting severe inflammation-associated impact in mice. • Therapeutic intervention of MyD88 also showed an increase in antiviral effect with strong type I IFN signaling linked to increased phosphorylation of IRFs via MyD88-independent pathway. • MyD88 inhibitors might be potentially useful as a small-molecule therapeutics for modulation of host immunity against inflammatory diseases and antiviral therapy. • However, prior clinical use of more in-depth efforts should be focused for suitability of the approach in deploying to complex diseases including COPD and COVID-19 in limiting inflammation-associated syndrome to infection.

The Two Faces of Nematode Infection: Virulence and Immunomodulatory Molecules From Nematode Parasites of Mammals, Insects and Plants

Helminths stage a powerful infection that allows the parasite to damage host tissue through migration and feeding while simultaneously evading the host immune system. This feat is accomplished in part through the release of a diverse set of molecules that contribute to pathogenicity and immune suppression. Many of these molecules have been characterized in terms of their ability to influence the infectious capabilities of helminths across the tree of life. These include nematodes that infect insects, known as entomopathogenic nematodes (EPN) and plants with applications in agriculture and medicine. In this review we will first discuss the nematode virulence factors, which aid parasite colonization or tissue invasion, and cause many of the negative symptoms associated with infection. These include enzymes involved in detoxification, factors essential for parasite development and growth, and highly immunogenic ES proteins. We also explore how these parasites use several classes of molecules (proteins, carbohydrates, and nucleic acids) to evade the host's immune defenses. For example, helminths release immunomodulatory molecules in extracellular vesicles that may be protective in allergy and inflammatory disease. Collectively, these nematode-derived molecules allow parasites to persist for months or even years in a host, avoiding being killed or expelled by the immune system. Here, we evaluate these molecules, for their individual and combined potential as vaccine candidates, targets for anthelminthic drugs, and therapeutics for allergy and inflammatory disease. Last, we evaluate shared virulence and immunomodulatory mechanisms between mammalian and non-mammalian plant parasitic nematodes and EPNs, and discuss the utility of EPNs as a cost-effective model for studying nematode-derived molecules. Better knowledge of the virulence and immunomodulatory molecules from both entomopathogenic nematodes and soil-based helminths will allow for their use as beneficial agents in fighting disease and pests, divorced from their pathogenic consequences.

An increase in p62/NBR1 levels in melioidosis patients of Sri Lanka exhibit a characteristic of potential host biomarker

Introduction. Melioidosis, caused by Burkholderia pseudomallei, in endemic areas, poses a challenge for treating the diseased populations without accurate diagnosis, and the disease-specific biomarkers linked with the infection have yet to be reported. Due to the invasive nature of the causative agent, Burkholderia pseudomallei, host innate effector mechanisms, including autophagy are known to be activated, resulting in differential expression of cellular proteins and immune markers. Identification of a disease-specific biomarker associated with B. pseudomallei infection will be helpful to facilitate rapid confirmation of melioidosis, which would enable early treatment and therapeutic success.Aim. We aimed to assess the levels of a host autophagy component, p62/NBR1, which function as a cargo-receptor in the process of autophagy activation leading to the degradation of ubiquitin-coated intracellular bacteria in which p62/NBR1 itself is degraded in the clearance of the pathogen. We further probed the extent of intracellular p62/NBR1 degradation and assessed its potential as a melioidosis biomarker.Methodology. We analysed peripheral blood mononuclear cell (PBMC) lysates using an ELISA-based assay for detecting cytosolic autophagy-related proteins p62/NBR1. We measured p62/NBR1 levels in diseased (confirmed B. pseudomallei infection) and non -diseased populations and utilized receiver operating characteristic (ROC) curve and max Youden index analysis for evaluating potential disease biomarker characteristics.Results. Our results revealed a three to fivefold increase in p62/NBR1 levels confirmed melioidosis cases compared to uninfected healthy donors. Comparable to p62/NBR1, levels of cytosolic LC3-I levels also increased, whereas the levels of degraded membrane bound form LC3-II was low, suggesting autophagy deficiency. Proinflammatory serum cytokine response, particularly IL-6, was consistently higher alongside B. pseudomallei infection in comparison to healthy controls.Conclusions. ROC curve and max Youden index analysis suggest that increased p62/NBR1 levels in diseased populations display characteristics of a potential disease biomarker in melioidosis and illustrates that an elevated p62/NBR1 level, in conjunction with B. pseudomallei infection associated with autophagy deficiency.

Synthetic small molecule analogues of the immunomodulatory Acanthocheilonema viteae product ES-62 promote metabolic homeostasis during obesity in a mouse model

One of the most rapidly increasing human public health problems is obesity, whose sequelae like type-2 diabetes, represent continuously worsening, life-long conditions. Over the last 15 years, data have begun to emerge from human and more frequently, mouse studies, that support the idea that parasitic worm infection can protect against this condition. We have therefore investigated the potential of two synthetic small molecule analogues (SMAs) of the anti-inflammatory Acanthocheilonema viteae product ES-62, to protect against metabolic dysfunction in a C57BL/6 J mouse model of high calorie diet-induced obesity. We found weekly subcutaneous administration of the SMAs in combination (1 μg of each), starting one week before continuous exposure to high calorie diet (HCD), decreased fasting glucose levels and reversed the impaired glucose clearance observed in male mice, when measured at approximately 7 and 13 weeks after exposure to HCD. Fasting glucose levels were also-reduced in male mice fed a HCD for some 38 weeks when given SMA-treatment 13 weeks after the start of HCD, indicating an SMA-therapeutic potential. For the most part, protective effects were not observed in female mice. SMA treatment also conferred protection against each of reduced ileum villus length and liver fibrosis, but more prominently in female mice. Previous studies in mice indicate that protection against metabolic dysfunction is usually associated with polarisation of the immune system towards a type-2/anti-inflammatory direction but our attempts to correlate improved metabolic parameters with such changes were unsuccessful. Further analysis will therefore be required to define mechanism of action. Nevertheless, overall our data clearly show the potential of the drug-like SMAs as a preventative or treatment for metabolic dysregulation associated with obesity.

Failure of the Anti-Inflammatory Parasitic Worm Product ES-62 to Provide Protection in Mouse Models of Type I Diabetes, Multiple Sclerosis, and Inflammatory Bowel Disease

Parasitic helminths and their isolated secreted products show promise as novel treatments for allergic and autoimmune conditions in humans. Foremost amongst the secreted products is ES-62, a glycoprotein derived from Acanthocheilonema viteae, a filarial nematode parasite of gerbils, which is anti-inflammatory by virtue of covalently-attached phosphorylcholine (PC) moieties. ES-62 has been found to protect against disease in mouse models of rheumatoid arthritis, systemic lupus erythematosus, and airway hyper-responsiveness. Furthermore, novel PC-based synthetic small molecule analogues (SMAs) of ES-62 have recently been demonstrated to show similar anti-inflammatory properties to the parent molecule. In spite of these successes, we now show that ES-62 and its SMAs are unable to provide protection in mouse models of certain autoimmune conditions where other helminth species or their secreted products can prevent disease development, namely type I diabetes, multiple sclerosis and inflammatory bowel disease. We speculate on the reasons underlying ES-62's failures in these conditions and how the negative data generated may help us to further understand ES-62's mechanism of action.

Synthetic analogues of the parasitic worm product ES-62 reduce disease development in in vivo models of lung fibrosis

Parasitic worms are receiving much attention as a potential new therapeutic approach to treating autoimmune and allergic conditions but concerns remain regarding their safety. As an alternative strategy, we have focused on the use of defined parasitic worm products and recently taken this one step further by designing drug-like small molecule analogues of one such product, ES-62, which is anti-inflammatory by virtue of covalently attached phosphorylcholine moieties. Previously, we have shown that ES-62 mimics are efficacious in protecting against disease in mouse models of rheumatoid arthritis, systemic lupus erythematosus and skin and lung allergy. Given the potential role of chronic inflammation in fibrosis, in the present study we have focused our attention on lung fibrosis, a debilitating condition for which there is no cure and which in spite of treatment slowly gets worse over time. Two mouse models of fibrosis - bleomycin-induced and LPS-induced - in which roles for inflammation have been implicated were adopted. Four ES-62 analogues were tested - 11a and 12b, previously shown to be active in mouse models of allergic and autoimmune disease and 16b and AIK-29/62 both of which are structurally related to 11a. All four compounds were found to significantly reduce disease development in both fibrosis models, as shown by histopathological analysis of lung tissue, indicating their potential as treatments for this condition.

Worms: Pernicious parasites or allies against allergies?

Type 2 immune responses are most commonly associated with allergy and helminth parasite infections. Since the discovery of Th1 and Th2 immune responses more than 30 years ago, models of both allergic disease and helminth infections have been useful in characterizing the development, effector mechanisms and pathological consequences of type 2 immune responses. The observation that some helminth infections negatively correlate with allergic and inflammatory disease led to a large field of research into parasite immunomodulation. However, it is worth noting that helminth parasites are not always benign infections, and that helminth immunomodulation can have stimulatory as well as suppressive effects on allergic responses. In this review, we will discuss how parasitic infections change host responses, the consequences for bystander immunity and how this interaction influences clinical symptoms of allergy.

The Untapped Pharmacopeic Potential of Helminths

The dramatic rise in immunological disorders that occurs with socioeconomic development is associated with alterations in microbial colonization and reduced exposure to helminths. Excretory-secretory (E/S) helminth products contain a mixture of proteins and low-molecular-weight molecules representing the primary interface between parasite and host. Research has shown great pharmacopeic potential for helminth-derived products in animal disease models and even in clinical trials. Although in its infancy, the translation of worm-derived products into therapeutics is highly promising. Here, we focus on important key aspects in the development of immunomodulatory drugs, also highlighting novel approaches that hold great promise for future development of innovative research strategies.

Development of a Novel Backbone Cyclic Peptide Inhibitor of the Innate Immune TLR/IL1R Signaling Protein MyD88

MyD88 is a cytoplasmic adaptor protein that plays a central role in signaling downstream of the TLRs and the IL1R superfamily. We previously demonstrated that MyD88 plays a critical role in EAE, the murine model of multiple sclerosis, and showed that the MyD88 BB-loop decoy peptide RDVLPGT ameliorates EAE. We now designed and screened a library of backbone cyclized peptides based on the linear BB loop peptide, to identify a metabolically stable inhibitor of MyD88 that retains the binding properties of the linear peptide. We identified a novel cyclic peptide protein mimetic that inhibits inflammatory responses to TLR ligands, and NFκB activation in response to IL-1 activation. The inhibitor, c(MyD 4-4), is metabolically stable in comparison to the linear peptide, blocks MyD88 in a specific manner, and inhibits MyD88 function by preventing MyD88 dimerization. Finally, treatment of mice with c(MyD 4-4) reduced the severity of clinical disease in the murine EAE model of multiple sclerosis. Thus, modulation of MyD88-dependent signaling using c(MyD 4-4) is a potential therapeutic strategy to lower innate immune inflammation in autoimmune CNS disease.