Prophylactic and therapeutic treatment with a synthetic analogue of a parasitic worm product prevents experimental arthritis and inhibits IL-1β production via NRF2-mediated counter-regulation of the inflammasome

Epigenetic changes induced by parasitic worms and their excretory-secretory products

Parasitic worms are pathogens of major medical and veterinary importance. They have evolved highly effective and sophisticated strategies of immune system manipulation, typically involving actively excreted/secreted (E-S) products. These molecules dampen and regulate the host immune responses that would otherwise result in parasite expulsion, thereby enabling the worms to survive in the host for many years, and they can also help prevent the potentially serious tissue damage that the worms can induce. Reflecting these E-S product-associated anti-inflammatory activities, there is also increasing evidence that parasitic worms and their products may serendipitously protect against allergic and autoimmune conditions and in addition, comorbidities of ageing that are associated with inflammatory responses, like type 2 diabetes and obesity. Research in this area has to date generally focused on identifying the cellular and effector targets of immunomodulation induced by the worm E-S products. However, increasing evidence that they can induce stably imprinted phenotypes of haematopoietic and stromal cells which promote their long-lasting survival has recently ignited interest in the ability of the molecules to epigenetically rewire cells to 'resolve and repair' phenotypes. Here, we review and discuss these new data in the context of their potential for exploitation in identifying novel gene signatures for the development of advanced and safe therapeutics for chronic inflammatory diseases.

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.

Dissolving microneedle patch-assisted transdermal delivery of methotrexate improve the therapeutic efficacy of rheumatoid arthritis

Methotrexate (MTX) is a first-line treatment for rheumatoid arthritis (RA), but its clinical use is greatly limited by the adverse effects and poor patient compliance caused by traditional oral administration or injection. In recent years, some transdermal drug delivery systems have received considerable attention due to overcoming these shortcomings. In this study, we developed dissolving microneedle patch (DMNP) for transdermal delivery of MTX to treat RA safely and effectively. The morphology, mechanical strength, skin insertion, drug content, in vitro transdermal delivery, and other properties of DMNP were characterized. Meanwhile, the adjuvant-induced arthritis model of rats was established to investigate the therapeutic effect of MTX-loaded DMNP in vivo. The results showed that the microneedles had excellent morphology with neat array and complete needles, good puncture performance and mechanical strength, and rapid intradermal dissolution rate. In vitro transdermal delivery results indicated that microneedles could significantly increase drug transdermal permeation compared with the cream group. The pharmacological study showed that MTX-loaded DMNP significantly alleviated paw swelling, inhibit inflammatory response via downregulating the levels of TNF-α and IL-1β, relieved synovium destruction with less cartilage erosion, and slowed the progression of RA in AIA rats. Besides, DMNP presented better therapeutic performance than cream or intragastric administration at the same dosage of MTX. In conclusion, the MTX-loaded dissolving microneedle patch has advantages of safety, convenience, and high efficacy over conventional administrations, laying a foundation for the transdermal drug delivery system treatment of rheumatoid arthritis.

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.

Conquering rheumatic diseases: are parasitic worms the answer?

Despite the introduction of novel treatment strategies, management of rheumatic disorders remains associated with substantial unmet clinical need. Of interest therefore, it has recently become apparent that there is a global inverse relationship between the incidence of such conditions and parasitic helminth infection, with striking examples involving rheumatoid arthritis (RA)/systemic lupus erythematosus (SLE) patients and filarial nematode worm infection in studies in India. Such findings reflect that helminths are master manipulators of the immune system, particularly in being able to modulate proinflammatory responses. The aim of this article is thus to consider findings to date on this exciting and intriguing research area to form an opinion on whether parasitic worms may be exploited to generate novel therapies for rheumatic diseases.

Gentiopicroside alleviates acute myocardial infarction injury in rats by disrupting Nrf2/NLRP3 signaling

The objective of the present investigation was to assess the protective impact of gentiopicroside (GPS) on acute myocardial infarction (AMI) through the modulation of NF-E2-related factor 2 (Nrf2)/nucleotide-binding oligomerization domain, leucine-rich repeat, and pyrin domain-containing 3 (NLRP3) signaling. H9c2 cells were subjected to varying concentrations of GPS, and subsequently, the cells and Sprague-Dawley (SD) rats were segregated into control, model, GPS, t-BHQ (an Nrf2 activator), and GPS + ML385 (an Nrf2 inhibitor) groups. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were analyzed. Reactive oxygen species (ROS) and cell apoptosis were assessed, while Nrf2 and the expression of the NLRP3 inflammatory body signal pathway were evaluated using western blot and immunofluorescence techniques. The infarct area and pathological changes were also examined. Treatment with varying doses of GPS resulted in increased viability of H9c2 cells. Notably, the model group exhibited significantly elevated levels of cell apoptosis, MDA, and ROS compared to the control group, while SOD and Nrf2 levels were significantly reduced. Furthermore, the expression of NLRP3, cleaved caspase-1, interleukin (IL)-1β, and IL-18 were found to be augmented. Following the implementation of GPS in cells and animals, there was a notable reduction in MDA and ROS levels, a decrease in the rate of cellular apoptosis, and a mitigation of inflammation scores. In addition, there was an increase in the expression of SOD and Nrf2. However, the protective effects of GPS were negated when co-administered with ML385. GPS exhibits therapeutic properties in AMI rats by activating Nrf2 expression, thereby reducing the NLRP3 inflammatory body and alleviating the inflammatory response and oxidative stress of myocardial cells. GPS may hold promise as a potential drug for the treatment of AMI.

Clinical Research Progress of Small Molecule Compounds Targeting Nrf2 for Treating Inflammation-Related Diseases

Studies have found that inflammation is a symptom of various diseases, such as coronavirus disease 2019 (COVID-19) and rheumatoid arthritis (RA); it is also the source of other diseases, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), lupus erythematosus (LE), and liver damage. Nrf2 (nuclear factor erythroid 2-related factor 2) is an important multifunctional transcription factor in cells and plays a central regulatory role in cellular defense mechanisms. In recent years, several studies have found a strong association between the activation of Nrf2 and the fight against inflammation-related diseases. A number of small molecule compounds targeting Nrf2 have entered clinical research. This article reviews the research status of small molecule compounds that are in clinical trials for the treatment of COVID-19, rheumatoid arthritis, Alzheimer’s disease, Parkinson’s disease, lupus erythematosus, and liver injury.

Lead optimisation efforts on a molecular prototype of the immunomodulatory parasitic protein ES-62

The immunomodulatory property of some parasitic helminths is well documented. The glycoprotein ES-62 from the nematode, acanthocheilonema viteae has been found to possess immunomodulatory properties. Two small molecule analogues (SMA’s) of ES-62 (S3 and S5) were found to mimic its immunomodulatory properties in vivo and were active in animal models of allergic, inflammatory and autoimmune diseases. In this work, new efforts were made to further optimise the activities of compound S3 by making small but directed structural changes. A variety of analogues based on the S3 prototype were simulated by making variations at one position and then screened in silico. The best compounds were selected based on predicted physiochemical properties and medicinal chemistry indices and synthesised. Structural elucidation was done via HNMR, LCMS, FTIR and HRESIMS. The predicted properties were evaluated by HPLC method. A total of 11 novel molecules were synthesised and characterised. Significant correlation was obtained between the predicted physicochemical properties and their HPLC retention times (RT) for eight of our novel compounds. This suggests that these compounds may behave in a physiological environment as closely as computationally predicted. This entails, lesser host toxicity while maintaining good or better activities compared to the earlier prototype. They hence provide a good opportunity for development of drugs for immune conditions such as asthma, inflammation and autoimmune diseases.

Cytohesin-2/ARNO: A Novel Bridge Between Cell Migration and Immunoregulation in Synovial Fibroblasts

The guanine nucleotide exchange factor cytohesin-2 (ARNO) is a major activator of the small GTPase ARF6 that has been shown to play an important role(s) in cell adhesion, migration and cytoskeleton reorganization in various cell types and models of disease. Interestingly, dysregulated cell migration, in tandem with hyper-inflammatory responses, is one of the hallmarks associated with activated synovial fibroblasts (SFs) during chronic inflammatory joint diseases, like rheumatoid arthritis. The role of ARNO in this process has previously been unexplored but we hypothesized that the pro-inflammatory milieu of inflamed joints locally induces activation of ARNO-mediated pathways in SFs, promoting an invasive cell phenotype that ultimately leads to bone and cartilage damage. Thus, we used small interference RNA to investigate the impact of ARNO on the pathological migration and inflammatory responses of murine SFs, revealing a fully functional ARNO-ARF6 pathway which can be rapidly activated by IL-1β. Such signalling promotes cell migration and formation of focal adhesions. Unexpectedly, ARNO was also shown to modulate SF-inflammatory responses, dictating their precise cytokine and chemokine expression profile. Our results uncover a novel role for ARNO in SF-dependent inflammation, that potentially links pathogenic migration with initiation of local joint inflammation, offering new approaches for targeting the fibroblast compartment in chronic arthritis and joint disease.

Kaempferol prevents cadmium chloride-induced liver damage by upregulating Nrf2 and suppressing NF-κB and keap1

This study evaluated the protective effect of kaempferol, a natural flavonoid, against cadmium chloride (CdCl₂)-induced liver damage and examined the possible anti-inflammatory and antioxidant mechanisms of protection. Adult male rats were divided into 4 groups (each of 8 rats) as control, kaempferol (50 mg/kg/day orally), CdCl₂ (15 ppm/day), and CdCl₂ (15 ppm/day) + kaempferol (50 mg/kg/day). All treatments were given for 30 days. With no effect on attenuating the reduced food intake, kaempferol significantly increased body weight and lowered serum levels of liver injury markers including bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma-glutamyltransferase 1 (γ-GTT1) in the CdCl₂-treated rats. It also restored normal liver architectures, prevented hepatocyte, loss, and swelling and reduced inflammatory cell infiltration. These effects were associated with a reduction in mitochondrial permeability transition pore, as well as in the expression of cytochrome-c and cleaved caspase-3, markers of mitochondrial damage, and intrinsic cell death. In both the control positive and CdCl₂-treated rats, kaempferol significantly lowered the hepatic levels of reactive oxygen species, malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), Interleukine-6 (IL-6), and the nuclear activity and localization of NF-κB p65. Besides, kaempferol significantly increased the hepatic total and nuclear levels of the nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1, as well as levels of superoxide dismutase (SOD) and reduced glutathione (GSH) but reduced the cytoplasmic protein levels of keap1. In conclusion, the protective effect of kaempferol against CdCl₂-induced hepatic damage is mediated by antioxidant and anti-inflammatory effects driven by upregulating Nrf2/HO-1 axis and suppressing the NF-κB p65 and keap1.

Nrf2 in the Field of Dentistry with Special Attention to NLRP3

The aim of this review article was to summarize the functional implications of the nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with special attention to the NACHT (nucleotide-binding oligomerization), LRR (leucine-rich repeat), and PYD (pyrin domain) domains-containing protein 3 (NLRP3) inflammasome in the field of dentistry. NLRP3 plays a crucial role in the progression of inflammatory and adaptive immune responses throughout the body. It is already known that this inflammasome is a key regulator of several systemic diseases. The initiation and activation of NLRP3 starts with the oral microbiome and its association with the pathogenesis and progression of several oral diseases, including periodontitis, periapical periodontitis, and oral squamous cell carcinoma (OSCC). The possible role of the inflammasome in oral disease conditions may involve the aberrant regulation of various response mechanisms, not only in the mouth but in the whole body. Understanding the cellular and molecular biology of the NLRP3 inflammasome and its relationship to Nrf2 is necessary for the rationale when suggesting it as a potential therapeutic target for treatment and prevention of oral inflammatory and immunological disorders. In this review, we highlighted the current knowledge about NLRP3, its likely role in the pathogenesis of various inflammatory oral processes, and its crosstalk with Nrf2, which might offer future possibilities for disease prevention and targeted therapy in the field of dentistry and oral health.

Helminth Glycans at the Host-Parasite Interface and Their Potential for Developing Novel Therapeutics

Helminths are parasitic worms that have successfully co-evolved with their host immune system to sustain long-term infections. Their successful parasitism is mainly facilitated by modulation of the host immune system via the release of excretory-secretory (ES) products covered with glycan motifs such as Lewis X, fucosylated LDN, phosphorylcholine and tyvelose. Evidence is accumulating that these glycans play key roles in different aspects of helminth infection including interactions with immune cells for recognition and evasion of host defences. Moreover, antigenic properties of glycans can be exploited for improving the efficacy of anti-helminthic vaccines. Here, we illustrate that glycans have the potential to open new avenues for the development of novel biopharmaceuticals and effective vaccines based on helminth glycoproteins.

Genistein mitigates oxidative stress and inflammation by regulating Nrf2/HO-1 and NF-κB signaling pathways in hypoxic-ischemic brain damage in neonatal mice

Background

Oxidative stress and neuroinflammation play crucial roles in the progression of neonatal hypoxic-ischemic brain damage (HIBD). Genistein, a natural phytoestrogen, has been found to protect against ischemic brain injury. However, its effects and potential mechanisms in HIBD have not yet been explored.

Methods

A neonatal mouse model of hypoxia-ischemia (HI) and a cell model of oxygen-glucose deprivation/reperfusion (OGD/R) were employed. In the in vivo study, genistein (10 mg/kg; ip) was administered in mice once daily for 3 consecutive days before the operation and once immediately after HI. The effects of genistein treatment on acute brain damage and long-term responses were evaluated. Neuronal injury and apoptosis were estimated using hematoxylin and eosin (H&E) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, respectively. The expression of apoptosis-related proteins were also measured by Western blot analysis. Dihydroethidium (DHE) staining and glutathione (GSH) and malondialdehyde (MDA) production were determined to assess the extent of oxidative stress. The messenger RNA (mRNA) levels of proinflammatory cytokines were detected using real-time quantitative polymerase chain reaction (RT-qPCR) to evaluate the extent of neuroinflammation. In the in vitro study, cell counting kit-8 (CCK-8) and lactate dehydrogenase (LDH) assays, as well as propidium iodide (PI) staining, were performed to analyse the neuroprotective effects of genistein on primary cortical neurons. Western blot assays were used to detect the levels of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), phosphorylated inhibitor kappa B-α (p-IκB-α) and phosphorylated nuclear factor-kappa B (p-NF-κB) both in vivo and in vitro.

Results

Our results showed that genistein treatment effectively reduced cerebral infarction, attenuated neuronal injury and apoptosis, and contributed to the long-term recovery of neurological outcomes and brain atrophy in neonatal HIBD mice. Moreover, genistein ameliorated HIBD-induced oxidative stress and neuroinflammation. Meanwhile, genistein significantly increased cell viability, reversed neuronal injury and decreased cell apoptosis after OGD/R injury. Finally, the activation of the Nrf2/HO-1 pathway and inhibition of the NF-κB pathway by genistein were verified in the brain tissues of neonatal mice subjected to HIBD and in primary cortical neurons exposed to OGD/R.

Conclusions

Genistein exerted neuroprotective effects on HIBD by attenuating oxidative stress and neuroinflammation through the Nrf2/HO-1 and NF-κB signalling pathways.

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.

Emerging Role of Eosinophils in Resolution of Arthritis

Eosinophils are a minor component of circulating granulocytes, which are classically viewed as end-stage effector cells in host defense against helminth infection and promoting allergic responses. However, a growing body of evidence has emerged showing that eosinophils are versatile leukocytes acting as an orchestrator in the resolution of inflammation. Rheumatoid arthritis (RA) is the most common chronic inflammatory disease characterized by persistent synovitis that hardly resolves spontaneously. Noteworthy, a specific population of eosinophils, that is, regulatory eosinophils (rEos), was identified in the synovium of RA patients, especially in disease remission. Mechanistically, the rEos in the synovium display a unique pro-resolving signature that is distinct from their counterpart in the lung. Herein, we summarize the latest understanding of eosinophils and their emerging role in promoting the resolution of arthritis. This knowledge is crucial to the design of new approaches to rebalancing immune homeostasis in RA, considering that current therapies are centered on inhibiting pro-inflammatory cytokines and mediators rather than fostering the resolution of inflammation.

Disruptive Selection of Human Immunostimulatory and Immunosuppressive Genes Both Provokes and Prevents Rheumatoid Arthritis, Respectively, as a Self-Domestication Syndrome

Using our previously published Web service SNP_TATA_Comparator, we conducted a genome-wide study of single-nucleotide polymorphisms (SNPs) within core promoters of 68 human rheumatoid arthritis (RA)-related genes. Using 603 SNPs within 25 genes clinically associated with RA-comorbid disorders, we predicted 84 and 70 candidate SNP markers for overexpression and underexpression of these genes, respectively, among which 58 and 96 candidate SNP markers, respectively, can relieve and worsen RA as if there is a neutral drift toward susceptibility to RA. Similarly, we predicted natural selection toward susceptibility to RA for 8 immunostimulatory genes (e.g., IL9R) and 10 genes most often associated with RA (e.g., NPY). On the contrary, using 25 immunosuppressive genes, we predicted 70 and 109 candidate SNP markers aggravating and relieving RA, respectively (e.g., IL1R2 and TGFB2), suggesting that natural selection can simultaneously additionally yield resistance to RA. We concluded that disruptive natural selection of human immunostimulatory and immunosuppressive genes is concurrently elevating and reducing the risk of RA, respectively. So, we hypothesize that RA in human could be a self-domestication syndrome referring to evolution patterns in domestic animals. We tested this hypothesis by means of public RNA-Seq data on 1740 differentially expressed genes (DEGs) of pets vs. wild animals (e.g., dogs vs. wolves). The number of DEGs in the domestic animals corresponding to worsened RA condition in humans was significantly larger than that in the related wild animals (10 vs. 3). Moreover, much less DEGs in the domestic animals were accordant to relieved RA condition in humans than those in the wild animals (1 vs. 8 genes). This indicates that the anthropogenic environment, in contrast to a natural one, affects gene expression across the whole genome (e.g., immunostimulatory and immunosuppressive genes) in a manner that likely contributes to RA. The difference in gene numbers is statistically significant as confirmed by binomial distribution (p < 0.01), Pearson's χ² (p < 0.01), and Fisher's exact test (p < 0.05). This allows us to propose RA as a candidate symptom within a self-domestication syndrome. Such syndrome might be considered as a human's payment with health for the benefits received during evolution.

Systems pharmacology-based dissection of mechanisms of Tibetan medicinal compound Ruteng as an effective treatment for collagen-induced arthritis rats

ETHNOPHARMACOLOGICAL RELEVANCE

Compound Ruteng (CRT) is a prescribed formulation based on the theory of Tibetan medicine for the treatment of yellow-water-disease. It is consisted with 7 medicinal material include Boswellia carterii Birdw (named "Ruxiang" in Chinese); Tinospora sinensis (Lour.) Merr. (named "Kuan-Jin-Teng" in Chinese), Cassia obtusifolia L (named "Jue-Ming-Zi" in Chinese); Abelmoschus manihot (L.) Medic (named "Huang-Kui-Zi" in Chinese); Terminalia chebula Retz. (named "He-Zi" in Chinese); Lamiophlomis rotata (Benth.) Kudo (named "Du-Yi-Wei" in Chinese) and Pyrethrum tatsienense (Bur. et Franch.) Ling (named "Da-Jian-Ju" in Chinese). They are widely distributed in Tibet area of China and have been used to treat rheumatism, jaundice, and skin diseases for centuries.

AIM OF THE STUDY

The present study was conducted to investigate the anti-arthritis effect of CRT and to disclose the systems pharmacology-based dissection of mechanisms.

MATERIALS AND METHODS

The chemical constituents in CRT were identified using HPLC method, and CRT candidate targets against RA were screened by network pharmacology-based analysis and further experimentally validated based on collagen-induced arthritis (CIA) rat model. Furthermore, therapeutic mechanisms and pathways of CRT were investigated.

RESULTS

391 potential targets (protein) were predicted against 92 active ingredients of 7 medicinal materials in CRT. Enrichment analysis and molecular docking studies also enforced the practiced results. X-ray based physiological imaging showed the attenuated effect of CRT on paw swelling, synovial joints and cartilage with improved inflammation in CIA rats. Moreover, the expression of biomarkers associated with RA such as MMP1, MMP3 and MMP13 and TNF-a, COX2 and iNOS are down-regulated in ankle joints, serum, or liver.

CONCLUSION

In conclusion, CRT compound could attenuate RA symptoms and active ingredients of this compound could be considered for drug designing to treat RA.

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.

Artesunate attenuates bone erosion in rheumatoid arthritis by suppressing reactive oxygen species via activating p62/Nrf2 signaling

Accumulating studies have indicated that reactive oxygen species (ROS) may be implicated into the destructive pathological events of rheumatoid arthritis (RA). As an effective antioxidant, artesunate (ARS) was reported to exert antiarthritic effects. However, whether ARS attenuates the bone erosion during RA progression by regulating ROS production remains to be defined. To address this problem, the inhibitive effects of ARS on osteoclastogenesis were observed in vitro. Mechanically, ARS significantly inhibited the NFATc1 signaling accompanied by markedly suppressing ROS production, which was abnormally enhanced during the pathological process of bone erosion. In addition, ARS may function as a potent ROS scavenger and significantly elevate the expression of HO-1 and NQO1 by activating Nrf2. Moreover, p62 accumulation induced by ARS was responsible for the activation of Nrf2, while the knockdown of p62 in osteoclast precursor cells diminished the suppressive effect of ARS on ROS production during osteoclastogenesis. Consistently, we also demonstrated that ARS effectively suppressed ROS production, leading to the inhibition of arthritic bone destruction by activating antioxidant enzyme and Nrf2/p62 signaling in the knee and ankle tissues of CIA rats. Collectively, our data offer the convincing evidence that ARS may inhibit osteoclastogenesis and ameliorate arthritic bone erosion through suppressing the generation of ROS via activating the p62/Nrf2 signaling.

Gross ways to live long: Parasitic worms as an anti-inflammaging therapy?

Evolutionary medicine argues that disease can arise because modern conditions do not match those in which we evolved. For example, a decline in exposure to commensal microbes and gastrointestinal helminths in developed countries has been linked to increased prevalence of allergic and autoimmune inflammatory disorders (the hygiene hypothesis). Accordingly, probiotic therapies that restore ‘old friend’ microbes and helminths have been explored as Darwinian treatments for these disorders. A further possibility is that loss of old friend commensals also increases the sterile, aging-associated inflammation known as inflammaging, which contributes to a range of age-related diseases, including cardiovascular disease, dementia, and cancer. Interestingly, Crowe et al., 2020 recently reported that treatment with a secreted glycoprotein from a parasitic nematode can protect against murine aging by induction of anti-inflammatory mechanisms. Here, we explore the hypothesis that restorative helminth therapy would have anti-inflammaging effects. Could worm infections provide broad-spectrum protection against age-related disease?

Perillaldehyde Ameliorates Aspergillus fumigatus Keratitis by Activating the Nrf2/HO-1 Signaling Pathway and Inhibiting Dectin-1-Mediated Inflammation

Purpose

The purpose of this study was to investigate the therapeutic effect of perillaldehyde (PAE) on Aspergillus fumigatus (A. fumigatus) keratitis.

Methods

Human corneal epithelial cells (HCECs) were pretreated with PAE and stimulated with A. fumigatus mycelium. C57BL/6 mice were infected with A. fumigatus and treated with or without PAE 1 day after infection. Clinical scores, PCR, ELISA, and Western blotting were used to detect the expression of pro-inflammatory mediators, dendritic cell-associated c-type lectin-1 (Dectin-1), nuclear factor (erythroid-derived 2) like 2 (Nrf2), and heme oxygenase (HO-1). Nrf2 expression in HCECs pretreated with PAE was observed by immunofluorescence. NIMP-R14 protein expression and localization in mouse corneas were observed by immunofluorescence staining after treatment with PAE. Corneal colony counting, time-kill tests, and mycelial transformation inhibition tests were used to evaluate the antifungal effect of PAE.

Results

C57BL/6 mice treated with PAE at 1 day after infection had a lower clinical score and decreased IL-1β, TNF-α, IL-6, Dectin-1, and MPO levels. PAE treatment significantly reduced neutrophil recruitments to the corneal stroma. Compared with the DMSO-treated group, PAE treatment significantly decreased mRNA and protein levels of pro-inflammatory cytokines and Dectin-1 in HCECs. PAE pretreatment before A. fumigatus stimulation obviously elevated the mRNA and protein levels of components of the Nrf2/HO-1 axis. HCECs pretreated with PAE before infection showed a weakened ability to inhibit inflammation in the presence of brusatol (BT; an Nrf2 inhibitor) or ZnPP (an HO-1 inhibitor). PAE treatment significantly reduced the fungal load of C57BL/6 mouse corneas and inhibited fungal growth in vitro.

Conclusions

These data proved that PAE may ameliorate A. fumigatus keratitis by activating the Nrf2/HO-1 signaling pathway and inhibiting the Dectin-1 mediated inflammatory response and neutrophil recruitment. Furthermore, PAE exerts direct fungicidal activity on A. fumigatus.

Heme oxygenase 1 plays a crucial role in swamp eel response to oxidative stress induced by cadmium exposure or Aeromonas hydrophila infection

Oxidative stress contributes a lot to initiation and progression of pathological conditions. Heme oxygenase 1 (HO1), a cytoprotective enzyme, is usually upregulated to alleviate oxidative stress in vivo. The function of teleost HO1 in the response to oxidative stress induced by heavy metal exposure and in pathogenic bacterial infection remains uncertain. In the present study, both complementary DNA and genomic sequence of a HO1-like gene cloned from the liver of swamp eel (Monopterus albus) are reported. Sequence analysis showed that the putative amino acid sequence contained a conserved heme oxygenase signature and displayed higher similarity to HO1 genes of other teleosts. Expression profile of swamp eel HO1 was investigated in healthy tissues and in tissues following stimulation with pathogenic bacteria (Aeromonas hydrophila) or cadmium chloride (CdCl₂) exposure. Results demonstrated that HO1 messenger RNA (mRNA) was highly expressed in the liver and relatively less in other tissues. Bacterial infection with A. hydrophila significantly changed HO1 mRNA expression in the liver, spleen, and kidney, and the mRNA expression of HO1 and Nrf2 in the liver was elevated after the fish were exposed to CdCl₂. Subsequently, the swamp eel HO1 was subcloned into a pET28a expression vector and transformed into Escherichia coli BL21 (DE3). Recombinant HO1 (rHO1) was successfully induced by 0.1 mmol/l IPTG and purified by Ni-NTA His Bind Resin purification system. To determine whether the rHO1 could confer stress tolerance in vitro, the viability of control and HO1-expressing E. coli under CdCl₂ stress was compared by spot assay. The rHO1 protein significantly increased survival rates of the bacterial hosts. To evaluate whether intraperitoneal injection with rHO1 protected the liver of swamp eel against A. hydrophila-induced oxidative stress, mRNA expression of HO1, Nrf2, hepcidin, and IL-1β as well as the oxidative stress-related parameters (ROS and total antioxidant capacity (T-AOC)) in the liver were examined. The results showed that exogenous rHO1 could significantly upgrade the mRNA expression of HO1 and hepcidin, coupled with increased ROS and T-AOC levels. However, Nrf2 and IL-1β expression levels were significantly downregulated and upregulated, respectively. These results suggested that HO1 should not only play a protective role in oxidative stress response and its adverse effects deserved further investigation.

Schistosome and intestinal helminth modulation of macrophage immunometabolism

Macrophages are fundamental to sustain physiological equilibrium and to regulate the pathogenesis of parasitic and metabolic processes. The functional heterogeneity and immune responses of macrophages are shaped by cellular metabolism in response to the host's intrinsic factors, environmental cues and other stimuli during disease. Parasite infections induce a complex cascade of cytokines and metabolites that profoundly remodel the metabolic status of macrophages. In particular, helminths polarize macrophages to an M2 state and induce a metabolic shift towards reliance on oxidative phosphorylation, lipid oxidation and amino acid metabolism. Accumulating data indicate that helminth-induced activation and metabolic reprogramming of macrophages underlie improvement in overall whole-body metabolism, denoted by improved insulin sensitivity, body mass in response to high-fat diet and atherogenic index in mammals. This review aims to highlight the metabolic changes that occur in human and murine-derived macrophages in response to helminth infections and helminth products, with particular interest in schistosomiasis and soil-transmitted helminths.

Evaluating the preventive and curative effects of Toxocara canis larva in Freund's complete adjuvant-induced arthritis

Helminthic infection and the parallel host immune reactions are the results of a protracted dynamic co-interaction between the host and worms. An assessment of the effect of Toxocara canis infection on arthritis in rats stimulated by Freund's complete adjuvant (FCA) was the main purpose of the investigation. An arthritis model was established by the administration of 0.1 mL FCA in the palmar surface. Cytokine assessment, evaluating oedema and the use of a rheumatoid arthritis (RA) score provided evidence of the protective effects of T canis against adjuvant-induced arthritis (AIA). The cytokines TGF-β, IFN-ɣ, IL-10 and IL-17 were measured to assess the anti-inflammatory effect of T canis infection. Besides, arthritis swelling findings were evaluated in rat paws. The data showed that T canis infection significantly modulated the immune response by alleviating inflammatory cytokines and increasing TGF-β as an anti-inflammatory cytokine. Evaluations of arthritis swelling showed low severity and faster recuperation. These findings suggest that the products derived from T canis eggs might be a potential therapeutic candidate to treat autoimmune diseases like the arthritis.

Immunomodulatory activity of gamma radiation-attenuated Toxoplasma gondii in adjuvant arthritic mice

There is growing evidence that some parasitic infections can impact a variety of autoimmune diseases by disease-inducing or protecting capacities. Anti-inflammatory molecules secreted by Toxoplasma gondii and other parasites are capable of preventing some autoimmune disease like arthritis, lupus nephritis and systemic lupus erythematosus by acting on the immune system. Here we aimed to evaluate the protective efficacy of vaccination with Toxoplasma gondii (T. gondii), either gamma radiation-attenuated or not, on an adjuvant arthritis mouse model. Forty female Swiss albino mice were conducted in experiment divided into normal control; mice were injected with Complete Freund's adjuvant (CFA) into the right hind paws; mice vaccinated with irradiated T. gondii in the 3rd group and un-irradiated T. gondii in the 4th group then were injected two weeks later with CFA. Histopathological changes and IL-17, STAT6 and ROR-γ levels in the joints, as well as serum survivin and Anti-CCP, were evaluated. Also, the splenic production of TGF-β1, TGF-βR, IL-23, IL-1β, IFN-γ, TFN-∞, NF_Kβ, MMP1 and MMP3 were assessed. Results exhibited an enhancement of the histopathological changes with diminished the rise of IL-17, STAT 6 and ROR- γ within the joints of both vaccinated groups. Also, serum survivin and Anti-CCP, as well as splenic inflammatory cytokines were reduced. It can be concluded that vaccination with un-irradiated or radiation-attenuated T. gondii exerted a protective effect against adjuvant arthritis with better pathological achievement in the radiation-attenuated vaccinated group. Using gamma radiation-attenuated parasite to exclude the delirious effects of imposing infection of live one may pave the way to new preventative modality against rheumatoid arthritis.

Pterostilbene induces Nrf2/HO-1 and potentially regulates NF-κB and JNK-Akt/mTOR signaling in ischemic brain injury in neonatal rats

Hypoxic-ischemic (HI) brain injury has a high occurrence rate of 1-4 per 1000 live births and is the leading cause of neurological disabilities. Despite the improvement in neonatal care, the effectiveness of current therapeutic strategies is limited, and thus, additional therapies with better results are of much needed. Pterostilbene is a stilbenoid possessing numerous preventive and therapeutic properties. The current study aimed to assess whether pterostilbene exerted protective effects in neonatal rats against experimentally induced ischemic brain injury. Pterostilbene was administered via oral gavage from postnatal day 3 to day 8. Rat pups that were seven-day-old were exposed to hypoxic-ischemic insult via ligation of the common carotid artery and hypoxic environment exposure. Pterostilbene treatment reduced neuronal loss and infarct volume. Pterostilbene administration regulated the NF-κB pathway, and the levels of inflammatory mediators (Nitric oxide, TNF-α, IL-1β, and IL-6) were reduced. HI-induced oxidative stress was significantly reduced by pterostilbene, as presented by decreased production of malondialdehyde and reactive oxygen species. Levels of glutathione were enhanced by pterostilbene. Pterostilbene regulated Nrf2/HO-1 and JNK expression and activated the PI3K/Akt-mTOR signals. These findings suggest that pterostilbene is a candidate compound for the treatment of neonatal HI.

Anti-inflammatory and immune-regulatory cytokines in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by a failure of spontaneous resolution of inflammation. Although the pro-inflammatory cytokines and mediators that trigger RA have been the focus of intense investigations, the regulatory and anti-inflammatory cytokines responsible for the suppression and resolution of disease in a context-dependent manner have been less well characterized. However, knowledge of the pathways that control the suppression and resolution of inflammation in RA is clinically relevant and conceptually important for understanding the pathophysiology of the disease and for the development of treatments that enable long-term remission. Cytokine-mediated processes such as the activation of T helper 2 cells by IL-4 and IL-13, the resolution of inflammation by IL-9, IL-5-induced eosinophil expansion, IL-33-mediated macrophage polarization, the production of IL-10 by regulatory B cells and IL-27-mediated suppression of lymphoid follicle formation are all involved in governing the regulation and resolution of inflammation in RA. By better understanding these immune-regulatory signalling pathways, new therapeutic strategies for RA can be envisioned that aim to balance and resolve, rather than suppress, inflammation.

Potential application of helminth therapy for resolution of neuroinflammation in neuropsychiatric disorders

Neuropsychiatric disorders (NPDs) are among the major debilitating disorders worldwide with multiple etiological factors. However, in recent years, psychoneuroimmunology uncovered the role of inflammatory condition and autoimmune disorders in the etiopathogenesis of different NPDs. Hence, resolution of inflammation is a new therapeutic target of NPDs. On the other hand, Helminth infections are among the most prevalent infectious diseases in underdeveloped countries, which usually caused chronic infections with minor clinical symptoms. Remarkably, helminths are among the master regulator of inflammatory reactions and epidemiological studies have shown an inverse association between prevalence of autoimmune disorders with these infections. As such, changes of intestinal microbiota are known to be associated with inflammatory conditions in various NPDs. Conversely, helminth colonization alters the intestinal microbiota composition that leads to suppression of intestinal inflammation. In animal models and human studies, helminths or their antigens have shown to be protected against severe autoimmune and allergic disorders, decline the intensity of inflammatory reactions and improved clinical symptoms of the patients. Therefore, "helminthic therapy" have been used for modulation of immune disturbances in different autoimmunity illnesses, such as Multiple Sclerosis (MS) and Inflammatory Bowel Disease (IBD). Here, it is proposed that "helminthic therapy" is able to ameliorate neuroinflammation of NPDs through immunomodulation of inflammatory reactions and alteration of microbiota composition. This review discusses the potential application of "helminthic therapy" for resolution of neuroinflammation in NPDs.

Cadmium Induces Acute Liver Injury by Inhibiting Nrf2 and the Role of NF-κB, NLRP3, and MAPKs Signaling Pathway

Acute Cadmium (Cd) exposure usually induces hepatotoxicity. It is well known that oxidative stress and inflammation causes Cd-induced liver injury. However, the effect of nuclear factor erythroid 2-related factor 2 (Nrf2) in Cd-induced liver injury is not completely understood. In this study, we observed Cd-induced liver damage and the potential contribution of Nrf2, nuclear factor-κB (NF-κB), Nod-like receptor 3 (NLRP3), and mitogen-activated protein kinases (MAPKs) signaling pathways. Changes in serum transaminases and proinflammatory cytokines expression showed that Cd could induce acute hepatotoxicity. Moreover, Nrf2 and its downstream heme oxygenase 1 (HO-1) were inhibited by Cd exposure, and Kelch-like ECH-associated protein 1 (Keap1), the inhibitory protein of Nrf2, was increased. Furthermore, NF-κB, NLRP3, and MAPKs signaling pathways were all activated by Cd intoxication. In conclusion, the inhibition of Nrf2, HO-1, and the activation of NF-κB, NLRP3, and MAPKs all contribute to Cd-induced liver injury.

Helminths Turning on the NLRP3 Inflammasome: Pros and Cons

Helminth infections can activate multimeric protein complexes called inflammasomes. In this forum we summarize the main effects of the NLRP3 inflammasome activation, including control of excessive Th2 response and immunopathology induction. These mechanisms would ensure the survival of both the host and the parasite.

Therapeutic applicability of helminths in autoimmune diseases - literature overview

This paper presents an overview of published studies conducted on helminths – parasites of the human gastrointestinal tract. Making use of their ability for immunomodulation may lead to the introduction of effective therapies for autoimmune diseases. This paper presents chronologically attempts to treat autoimmune diseases not only of the gastrointestinal tract, but also of the nervous and endocrine systems, which have been undertaken for decades. The overview of analysed reports demonstrates that as medical knowledge on the cells and mediators participating actively in inflammatory processes accumulates, clinical trials focus on ever more specific areas concerning the pathomechanisms of autoimmune diseases. The outcomes of clinical trials conducted both on animals and humans give reasons to assume that the modification of the human intestinal microflora may be the key to fighting against these diseases.

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.

Inflammasomes and autoimmune and rheumatic diseases: A comprehensive review

Inflammasomes are a multi-protein platform forming a part of the innate immune system. Inflammasomes are at standby status and can be activated when needed. Inflammasome activation is an important mechanism for the production of active interleukin (IL)-1β and IL-18, which have important roles to instruct adaptive immunity. Active forms of inflammasomes trigger a series of inflammatory cascades and lead to the differentiation and polarization of naïve T cells and secretion of various cytokines, which can induce various kinds of autoimmune and rheumatic diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), gout, Sjögren's syndrome, Behçet's disease, anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis and IgA vasculitis (former Henoch-Schönlein purpura ). In this review, we summarize studies published on inflammasomes and review their roles in various autoimmune diseases. Understanding of the role of inflammasomes may facilitate the diagnosis of autoimmune diseases and the development of tailored therapies in the future.

Neuroprotective effects of isoliquiritigenin against cognitive impairment via suppression of synaptic dysfunction, neuronal injury, and neuroinflammation in rats with kainic acid-induced seizures

Epileptogenesis is a dynamic process initiated by insults to brain and commonly accompanied by cognitive impairment. Isoliquiritigenin (ISL), a flavonoid in licorice, has a broad spectrum of biological effects including anti-inflammatory and antioxidant activities. However, the protective effects of ISL against cognitive impairment in epileptic processes and the underlying molecular mechanism are not well understood. To address these questions, we established an reproducible seizure model by intracerebroventricular injection of kainic acid (KA) in 21-day-old rats; ISL was intraperitoneally administered three times prior to KA injection, and changes in cognitive function; synaptic plasticity; neuronal injury; number of glial cells; and expression of pro-inflammatory cytokines and nuclear factor-like (NRF)2 signaling and NACHT, LRR, and PYD domains-containing protein (NLRP)3 inflammasome components in the hippocampus were examined. Rats with KA-induced seizures showed longer average escape latency and decreases in the number of platform crossings and average time spent in the target quadrant in the Morris water maze; ISL pretreatment reversed this decline in cognitive impairment and increased the protein levels of synaptophysin, postsynaptic density-95 and brain-derived neurotrophic factor while reducing the number of Fluoro Jade B-positive cells, microglia, and astrocytes; cleaved-Caspase-3 and -9 protein levels; and tumor necrosis factor-α, interleukin (IL)-1β, and IL-18 production. It also enhanced the nuclear localization of NRF2, hemeoxygenase-1, and NAD(P)H:quinone oxidoreductase (NQO) 1, and reversed the upregulation of NLRP3 inflammasome components NLRP3 and Caspase-1 induced by KA injection. Thus, ISL protects against cognitive impairment in KA-induced epileptic processes possibly through regulation of NRF2 signaling and the NLRP3 inflammasome pathway.

The parasitic worm product ES-62 normalises the gut microbiota bone marrow axis in inflammatory arthritis

The human immune system has evolved in the context of our colonisation by bacteria, viruses, fungi and parasitic helminths. Reflecting this, the rapid eradication of pathogens appears to have resulted in reduced microbiome diversity and generation of chronically activated immune systems, presaging the recent rise of allergic, autoimmune and metabolic disorders. Certainly, gastrointestinal helminths can protect against gut and lung mucosa inflammatory conditions by modulating the microbiome and suppressing the chronic inflammation associated with dysbiosis. Here, we employ ES-62, an immunomodulator secreted by tissue-dwelling Acanthocheilonema viteae to show that helminth-modulation of the gut microbiome does not require live infection with gastrointestinal-based worms nor is protection restricted to mucosal diseases. Specifically, subcutaneous administration of this defined immunomodulator affords protection against joint disease in collagen-induced arthritis, a mouse model of rheumatoid arthritis, which is associated with normalisation of gut microbiota and prevention of loss of intestinal barrier integrity.

NLRP3 inflammasome in ischemic stroke: As possible therapeutic target

Inflammation is a devastating pathophysiological process during stroke, a devastating disease that is the second most common cause of death worldwide. Activation of the NOD-like receptor protein (NLRP3)-infammasome has been proposed to mediate inflammatory responses during ischemic stroke. Briefly, NLRP3 inflammasome activates caspase-1, which cleaves both pro-IL-1 and pro-IL-18 into their active pro-inflammatory cytokines that are released into the extracellular environment. Several NLRP3 inflammasome inhibitors have been promoted, including small molecules, type I interferon, micro RNAs, nitric oxide, and nuclear factor erythroid-2 related factor 2 (Nrf2), some of which are potentially efficacious clinically. This review will describe the structure and cellular signaling pathways of the NLRP3 inflammasome during ischemic stroke, and current evidence for NLRP3 inflammasome inhibitors.

Autophagy Attenuates Angiotensin II-Induced Pulmonary Fibrosis by Inhibiting Redox Imbalance-Mediated NOD-Like Receptor Family Pyrin Domain Containing 3 Inflammasome Activation

AIMS

The NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, which is activated by reactive oxygen species (ROS) and repressed by autophagy, has been identified as a novel agent of pulmonary fibrosis. Angiotensin II (AngII), the bioactive pro-oxidant in the renin-angiotensin system, aggravates lung fibrosis. However, the effect of AngII on NLRP3 inflammasome and autophagy in lung fibrosis remains unknown. This study investigates the potential link between AngII-induced autophagy in the regulation of NLRP3 inflammasome/IL-1β axis in lung fibrosis.

RESULTS

In vivo, autophagy and the NLRP3 inflammasome were activated in fibrotic patients and positively correlated with oxidation. Treatment with rapamycin promoted autophagy but inhibited oxidation, NLRP3 inflammasome, and lung fibrosis after bleomycin (BLM) infusion. The autophagy inhibitor 3-methyladenine reduced BLM-induced lung fibrosis and concurrently facilitated NLRP3 inflammasome activation and oxidation in fibroblasts. In vitro, AngII promoted intercellular ROS, hydrogen peroxide, and NADPH oxidase 4 (NOX4) protein levels and reduced the glutathione concentration, thereby leading to NLRP3 inflammasome activation and consequent collagen synthesis. AngII induced autophagy, while VAS2870, NOX4, small-interfering RNA (siRNA), and compound C eliminated AngII-induced LC3B augmentation. Moreover, blocking autophagy with bafilomycin A1 or LC3B siRNA resulted in oxidant accumulation, NLRP3 inflammasome hyperactivation, and collagen deposition. Finally, AngII induced P62/SQSTM1, targeting ubiquitinated apoptosis-associated speck-like protein containing a CARD for degradation, thereby contributing to NLRP3 inflammasome inactivation. Innovation and Conclusion: Autophagy attenuates pulmonary fibrosis by regulating NLRP3 inflammasome activation induced by AngII-mediated ROS via redox balance modulation.

Helminth-based therapies for rheumatoid arthritis: A systematic review and meta-analysis

OBJECTIVE

Proteins from parasitic worms have been posed as novel therapies for rheumatoid arthritis (RA) and other auto-inflammatory diseases. However, with so many potential therapeutics, it is important that drug discovery be based on the specific phyla or species which show the most promising effects. Therefore, the aim of this systematic review and meta-analysis was to evaluate the reported effects of helminthic secretory proteins and derivative therapy on RA in an animal model.

METHODS

Medline, Scopus and Web of Science were searched to identify studies evaluating helminthic therapy in the collagen-induced arthritis model of RA. A meta-analysis was undertaken to determine the overall effect of the proteins. Subgroup analyses were also undertaken to investigate individual treatments.

RESULTS

Seven articles were included in the analysis. Overall, helminthic therapy significantly reduced arthritis score (SMD -1.193, 95% CI -1.525, -0.860). Subgroup analyses found a significant reduction in arthritis score following treatment with helminth protein ES-62 (SMD -1.186, 95% CI -1.633, -0.738) and phosphorylcholine-based treatment (SMD -0.997, 95% CI -1.423, -0.571). Subgroup analyses found ES-62 treatment significantly decreased IFN-γ levels (SMD -1.611, 95% CI -2.734, -0.487) and significantly increased levels of IL-10 (SMD 0.946, 95% CI 0.127, 1.765).

CONCLUSIONS

Therapeutics from parasitic worms are a promising avenue for drug discovery, especially with all included studies reporting a significant improvement in arthritis score. Based on pooled data presented in this study, the nematode Acanthocheilonema viteae seems to be of particular interest for therapeutics.

Crosstalk of toll-like receptors signaling and Nrf2 pathway for regulation of inflammation

Inflammation as a second line of defense of innate immunity plays a crucial role in eliminating invading pathogens (bacteria, viruses, fungi as well as other parasites). The inflammatory response may also activate adaptive immune system involving lymphocytes to mount either antibody dependent or cell-mediated immune responses to clear pathogenic insult. However, if continued, the inflammatory processes may become uncontrolled culminating in cellular injury and tissue destruction, thereby manifesting itself in chronic form. The chronic inflammation has been associated with numerous human pathological conditions like allergies and autoimmune diseases, atherosclerosis, arthritis, Alzheimer's disease, cancer, obesity, type 2 diabetes, schizophrenia, neuro-degenerative diseases and numerous others. The dysregulated inflammatory process is associated with overproduction of free radicals leading to oxidative stress and activation of different cell signaling pathways. The regulation of inflammation by TLR signaling as well as Nrf2 pathways separately is widely documented. Since both these major signaling pathways modulate inflammation, they may crosstalk to bring about coordinated inflammatory responses. The linkage between TLR signaling and Nrf2-Keap1 pathway may serve as a bridge between immune regulation and oxidative stress responses through regulation of inflammation. Also, inflammation is reportedly responsible for the plethora of diseased conditions; a study of its regulation by targeting the TLR-Nrf2 cross-talks may also be beneficial for the development of therapeutic therapies or prophylactic treatments. Hence, present review focuses on the crosstalk between TLR signaling and Nrf2 pathway with respect to their role in modulation of inflammation in normal as well as pathologic conditions.

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.

Immunomodulation by Helminths: Intracellular Pathways and Extracellular Vesicles

Helminth parasites are masters at manipulating host immune responses, using an array of sophisticated mechanisms. One of the major mechanisms enabling helminths to establish chronic infections is the targeting of pattern recognition receptors (PRRs) including toll-like receptors, C-type lectin receptors, and the inflammasome. Given the critical role of these receptors and their intracellular pathways in regulating innate inflammatory responses, and also directing adaptive immunity toward Th1 and Th2 responses, recognition of the pathways triggered and/or modulated by helminths and their products will provide detailed insights about how helminths are able to establish an immunoregulatory environment. However, helminths also target PRRs-independent mechanisms (and most likely other yet unknown mechanisms and pathways) underpinning the battery of different molecules helminths produce. Herein, the current knowledge on intracellular pathways in antigen presenting cells activated by helminth-derived biomolecules is reviewed. Furthermore, we discuss the importance of helminth-derived vesicles as a less-appreciated components released during infection, their role in activating these host intracellular pathways, and their implication in the development of new therapeutic approaches for inflammatory diseases and the possibility of designing a new generation of vaccines.

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.

Helminths-based bi-functional molecule, tuftsin-phosphorylcholine (TPC), ameliorates an established murine arthritis

A novel small molecule named tuftsin-phosphorylcholine (TPC), which is linked to the biological activity of helminths, was constructed. The current study address the effect of TPC treatment in established collagen-induced arthritis (CIA) mice and propose TPC bi-functional activity. TPC treatment was initiated when clinical score was 2 to 4. Arthritis scores in TPC treated mice were lower compared to mice treated with vehicle (P < 0.001). Joint staining showed normal joint structure in TPC-treated mice compared to control groups treated with phosphate buffered saline (PBS), phosphorylcholine, or tuftsin, which exhibited severely inflamed joints. TPC enhanced anti-inflammatory response due to increased IL-10 secretion, and reduced pro-inflammatory cytokine secretion (IL-1-β, IL-6, TNF-αP < 0.001). Furthermore, TPC therapy increased expansion of CD4⁺CD25⁺FOXP3⁺T regulatory cells and IL-10⁺CD5⁺CD1d⁺B regulatory cells. We propose that the immunomodulatory activity of TPC can be a result of a bi-specific activity of TPC: (a) The tuftsin part of the TPC shifts RAW macrophage cells from pro-inflammatory macrophages M1 to anti-inflammatory M2-secreting IL-10 (P < 0.001) through neuropilin-1 and (b) TPC significantly reduce mouse TLR4 expression via NFkB pathway by HEK^TM cells (P < 0.02) via the phosphorylcholine site of the molecule. Our results indicate that TPC, significantly ameliorated established CIA by its immunomodulatory activity. These data could lead to a novel self bi-functional small molecule for treating patients with progressive RA.

Protection Against Arthritis by the Parasitic Worm Product ES-62, and Its Drug-Like Small Molecule Analogues, Is Associated With Inhibition of Osteoclastogenesis

The immunomodulatory actions of parasitic helminth excretory-secretory (ES) products that serendipitously protect against development of chronic inflammatory disorders are well established: however, knowledge of the interaction between ES products and the host musculoskeletal system in such diseases is limited. In this study, we have focused on ES-62, a glycoprotein secreted by the rodent filarial nematode Acanthocheilonema viteae that is immunomodulatory by virtue of covalently attached phosphorylcholine (PC) moieties, and also two synthetic drug-like PC-based small molecule analogues (SMAs) that mimic ES-62's immunomodulatory activity. We have previously shown that each of these molecules prevents development of pathology in collagen-induced arthritis (CIA), a model of the musculoskeletal disease rheumatoid arthritis (RA) and reflecting this, we now report that ES-62 and its SMAs, modify bone remodeling by altering bone marrow progenitors and thus impacting on osteoclastogenesis. Consistent with this, we find that these molecules inhibit functional osteoclast differentiation in vitro. Furthermore, this appears to be achieved by induction of anti-oxidant response gene expression, thereby resulting in reduction of the reactive oxygen species production that is necessary for the increased osteoclastogenesis witnessed in musculoskeletal diseases like RA.

The Crosstalk between Nrf2 and Inflammasomes

The Nrf2 (nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2) transcription factor is a key player in cytoprotection and activated in stress conditions caused by reactive oxygen species (ROS) or electrophiles. Inflammasomes represent central regulators of inflammation. Upon detection of various stress factors, assembly of the inflamasome protein complex results in activation and secretion of proinflammatory cytokines. In addition, inflammasome activation causes pyroptosis, a lytic form of cell death, which supports inflammation. There is growing evidence of a crosstalk between the Nrf2 and inflammasome pathways at different levels. For example, Nrf2 activating compounds inhibit inflammasomes and consequently inflammation. This review summarizes what is known about the complex and predominantly antagonistic relationship of both stress-activated pathways.

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

ES-62 is a protein secreted by the parasitic worm Acanthocheilonema viteae that is anti-inflammatory by virtue of covalently attached phosphorylcholine. Previously we have reported that drug-like Small Molecule Analogues (SMAs) of its phosphorylcholine moiety can mimic ES-62 in protecting against disease development in certain mouse models of autoimmune and allergic conditions, due to them causing partial degradation of the TLR/IL-1R adaptor MyD88. We have now taken a molecular modelling approach to investigating the mechanism underlying this effect and this predicts that the SMAs interact directly with the MyD88 TIR domain. Further support for this is provided by assay of LPS-induced MyD88/NF-κB-driven secreted alkaline phosphatase (SEAP) reporter activity in commercially-available stably transfected (TLR4-MD2-NF-κB-SEAP) HEK293 cells, as SMA12b-mediated inhibition of such SEAP activity is blocked by its pre-incubation with recombinant MyD88-TIR domain. Direct binding of SMA12b to the TIR domain is also shown to inhibit homo-dimerization of the adaptor, an event that can explain the observed degradation of the adaptor and inhibition of subsequent downstream signalling. Thus, these new data identify initial events by which drug-like ES-62 SMAs, which we also demonstrate are able to inhibit cytokine production by human cells, homeostatically maintain "safe" levels of MyD88 signalling.

Licochalcone A activates Keap1-Nrf2 signaling to suppress arthritis via phosphorylation of p62 at serine 349

Licochalcone A (LCA) is derived from glycyrrhizae radix with antimicrobial, antitumor and anti-inflammatory activities. However, the anti-arthritic function of LCA and underlying mechanism has not been yet explored. The current study investigated the anti-arthritic effect of LCA and elucidated the underlying mechanism. The results showed that LCA significantly suppressed arthritis via the activation of SQSTM1 (p62)/nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling in the collagen-induced arthritis (CIA) model of DBA mice. In coincided with the results, this anti-arthritic effect of LCA was remarkably diminished in the collagen antibody-induced arthritis (CAIA) model of Nrf2-/- mice. These findings indicate that p62/Nrf2 signaling is a crucial pathway for the induction and treatment of arthritis. To further validate the effect of LCA on the arthritis, rheumatoid arthritis synovial fibroblasts (RASFs) isolated from the synovium of RA patients were employed in the study. In coincided with in vivo results, LCA inhibited the cell proliferation and arrested the cell cycle, induced apoptosis, suppressed pro-inflammatory cytokine secretion and increased expression of antioxidant enzymes via the activation of Keap1-Nrf2 signaling by enhancing p62 phosphorylation and expression, Nrf2 accumulation and Nrf2 nucleus translocation. Findings in the current study provide evidence that p62-Keap1-Nrf2 axis is a pivotal signaling pathway in development of arthritis and therapeutic efficacy of drugs, and LCA activates of Keap1-Nrf2 signaling to suppress arthritis by phosphorylation of p62 at Ser349. Collectively, LCA is valuable to be further investigated as a lead compound for application in anti-arthritis, and interference with the interaction between Nrf2 and Keap1 by phosphorylation of p62 may be a promising strategy for the discovery of anti-arthritic agents.