Amelioration of experimental autoimmune encephalitis by novel peptides: Involvement of T regulatory cells

Lichen Sclerosus: A Current Landscape of Autoimmune and Genetic Interplay

Lichen sclerosus (LS) is an acquired chronic inflammatory dermatosis predominantly affecting the anogenital area with recalcitrant itching and soreness. Progressive or persistent LS may cause urinary and sexual disturbances and an increased risk of local skin malignancy with a prevalence of up to 11%. Investigations on lipoid proteinosis, an autosomal recessive genodermatosis caused by loss-of-function mutations in the extracellular matrix protein 1 (ECM1) gene, led to the discovery of a humoral autoimmune response to the identical molecule in LS, providing evidence for an autoimmune and genetic counterpart targeting ECM1. This paper provides an overview of the fundamental importance and current issue of better understanding the immunopathology attributed to ECM1 in LS. Furthermore, we highlight the pleiotropic action of ECM1 in homeostatic and structural maintenance of skin biology as well as in a variety of human disorders possibly associated with impaired or gained ECM1 function, including the inflammatory bowel disease ulcerative colitis, Th2 cell-dependent airway allergies, T-cell and B-cell activation, and the demyelinating central nervous system disease multiple sclerosis, to facilitate sharing the concept as a plausible therapeutic target of this attractive molecule.

Immunomodulatory peptides-A promising source for novel functional food production and drug discovery

Immunomodulatory peptides are a complex class of bioactive peptides that encompasses substances with different mechanisms of action. Immunomodulatory peptides could also be used in vaccines as adjuvants which would be extremely desirable, especially in response to pandemics. Thus, immunomodulatory peptides in food of plant origin could be regarded both as valuable suplements of novel functional food preparation and/or as precursors or possible active ingredients for drugs design for treatment variety of conditions arising from impaired function of immune system. Given variety of mechanisms, different tests are required to assess effects of immunomodulatory peptides. Some of those effects show good correlation with in vivo results but others, less so. Certain plant peptides, such as defensins, show both immunomodulatory and antimicrobial effect, which makes them interesting candidates for preparation of functional food and feed, as well as templates for design of synthetic peptides.

The Potential of Food Protein-Derived Bioactive Peptides against Chronic Intestinal Inflammation

Inflammation can cause various chronic diseases like inflammatory bowel diseases. Various food protein-derived bioactive peptides (BAPs) with anti-inflammatory activity have the potential to manage these diseases. The aim of this paper is to overview the mechanisms and the molecular targets of BAPs to exert anti-inflammatory activity. In this review, the in vitro and in vivo effects of BAPs on intestinal inflammation are highlighted. The mechanism, pathways, and future perspectives of BAPs as the potential sources of therapeutic treatments to alleviate intestinal inflammation are provided, including nuclear factor-κB, mitogen-activated protein kinase, Janus kinase-signal transducer and activator of transcription, and peptide transporter 1 (PepT1), finding that PepT1 and gut microbiota are the promising targets for BAPs to alleviate the intestinal inflammation. This review provides a comprehensive understanding of the role of dietary BAPs in attenuating inflammation and gives a novel direction in nutraceuticals for people or animals with intestinal inflammation.

Molecular action mechanism of anti-inflammatory hydrolysates obtained from brewers' spent grain

BACKGROUND

Brewers' spent grain (BSG) is a relevant, protein-rich by-product of the brewing process. Protein hydrolysates from different sources exert immune-regulatory actions activating toll-like receptors (TLRs), nuclear factor kappa B (NFκB), and mitogen-activated protein kinases (MAPKs). Effects of gastrointestinal digestion have been poorly studied. Here, we studied the immune-regulatory effect of BSG hydrolysates, and their in-vitro-digested products, on rat splenocytes, macrophages, and T lymphocytes RESULTS: In primary cultures of rat spleen cells, BSG hydrolysates induced interleukin 10 and tumor necrosis factor production in basal conditions. Under stimulation with lipopolysaccharide or concanavalin A, hydrolysates further induced interleukin 10 production. Tumor necrosis factor and interferon-γ were inhibited in lipopolysaccharide- and concanavalin-A-stimulated cells respectively. In vitro gastrointestinal digestion attenuated the observed effects. Splenic macrophages and T lymphocytes behaved in a similar fashion. In spleen cells from TLR2^-/- and TLR4^-/- mice, immune-regulatory effects were greatly reduced or abrogated. The study of signal transduction pathways indicated a major involvement of NFκB, and the contribution of MAPKs p38, c-Jun N-terminal kinase, and extracellular signal-regulated kinases 1 and 2.

CONCLUSION

BSG hydrolysates, like those obtained from other food sources, regulate the immune response, involving TLR2 and TLR4 and the activation of NFκB and MAPKs, an effect partly maintained after in vitro gastrointestinal digestion. Our data support the hypothesis of a shared, rather unspecific, mechanism of action of protein hydrolysates. © 2020 Society of Chemical Industry.

Antiinflammatory peptides: current knowledge and promising prospects

BACKGROUND

Inflammation is part of the regular host reaction to injury or infection caused by toxic factors, pathogens, damaged cells, irritants, and allergens. Antiinflammatory peptides (AIPs) are present in all living organisms, and many peptides from herbal, mammalian, bacterial, and marine origins have been shown to have antimicrobial and/or antiinflammatory properties.

METHODS

In this study, we investigated the effects of antiinflammatory peptides on inflammation, and highlighted the underlying mechanisms responsible for these effects.

RESULTS

In multicellular organisms, including humans, AIPs constitute an essential part of their immune system. In addition, numerous natural and synthetic AIPs are effective immunomodulators and can interfere with signal transduction pathways involved in inflammatory cytokine expression. Among them, some peptides such as antiflammin, N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), and those derived from velvet antler proteins, bee venom, horse fly salivary gland, and bovine β-casein have received considerable attention over the past few years.

CONCLUSION

This article presents an overview on the major properties and mechanisms of action associated with AIPs as immunomodulatory, chemotactic, antioxidant, and antimicrobial agents. In addition, the results of various studies dealing with effects of AIPs on numerous classical models of inflammation are reviewed and discussed.

Anti-CD40 Ab- or 8-oxo-dG-enhanced Treg cells reduce development of experimental autoimmune encephalomyelitis via down-regulating migration and activation of mast cells

This study investigated whether anti-CD40 Ab and 8-oxo-dG attenuate mast cell migration and EAE development. Anti-CD40 Ab and 8-oxo-dG reduced EAE scores, mast cell numbers, expression of adhesion molecules, OX40L and Act1, levels of TNF-α, LTs, expression of cytokines, and co-localization of Treg cells and mast cells, all of which are increased in EAE-brain tissues. Each treatment enhanced Treg cells, expression of OX40, and cytokines related to suppressive function of Treg cells in EAE brain tissues. Act-BMMCs with Treg cells reduced expression of OX40L and CCL2/CCR2, VCAM-1, PECAM-1, [Ca²⁺]i levels, release of mediators, various signaling molecules, Act1 related to IL-17a signals versus those in act-BMMCs without Treg cells. The data suggest that IL-10- and IL-35-producing Foxp3⁺-Treg cells, enhanced by anti-CD40 Ab or 8-oxo-dG, suppress migration of mast cells through down-regulating the expression of adhesion molecules, and suppress mast cell activation through cell-to-cell cross-talk via OX40/OX40L in EAE development.

Selective inhibition of CCR7(-) effector memory T cell activation by a novel peptide targeting Kv1.3 channel in a rat experimental autoimmune encephalomyelitis model

The voltage-gated Kv1.3 K(+) channel in effector memory T cells serves as a new therapeutic target for multiple sclerosis. In our previous studies, the novel peptide ADWX-1 was designed and synthesized as a specific Kv1.3 blocker. However, it is unclear if and how ADWX-1 alleviates experimental autoimmune encephalomyelitis, a model for multiple sclerosis. In this study, the administration of ADWX-1 significantly ameliorated the rat experimental autoimmune encephalomyelitis model by selectively inhibiting CD4(+)CCR7(-) phenotype effector memory T cell activation. In contrast, the Kv1.3-specific peptide had little effect on CD4(+)CCR7(+) cells, thereby limiting side effects. Furthermore, we determined that ADWX-1 is involved in the regulation of NF-κB signaling through upstream protein kinase C-θ (PKCθ) in the IL-2 pathway of CD4(+)CCR7(-) cells. The elevated expression of Kv1.3 mRNA and protein in activated CD4(+)CCR7(-) cells was reduced by ADWX-1 engagement; however, an apparent alteration in CD4(+)CCR7(+) cells was not observed. Moreover, the selective regulation of the Kv1.3 channel gene expression pattern by ADWX-1 provided a further and sustained inhibition of the CD4(+)CCR7(-) phenotype, which depends on the activity of Kv1.3 to modulate its activation signal. In addition, ADWX-1 mediated the activation of differentiated Th17 cells through the CCR7(-) phenotype. The efficacy of ADWX-1 is supported by multiple functions, which are based on a Kv1.3(high) CD4(+)CCR7(-) T cell selectivity through two different pathways, including the classic channel activity-associated IL-2 pathway and the new Kv1.3 channel gene expression pathway.

Immune modulating peptides for the treatment and suppression of multiple sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease in which the immune system recognizes proteins of the myelin sheath as antigenic, thus initiating an inflammatory reaction in the central nervous system. This leads to demyelination of the axons, breakdown of the blood-brain barrier, and lesion formation. Current therapies for the treatment of MS are generally non-specific and weaken the global immune system, thus making the individual susceptible to opportunistic infections. Antigenic peptides and their derivatives are becoming more prevalent for investigation as therapeutic agents for MS because they possess immune-specific characteristics. In addition, other peptides that target vital components of the inflammatory immune response have also been developed. Therefore, the objectives of this review are to (a) summarize the immunological basis for the development of MS, (b) discuss specific and non-specific peptides tested in EAE and in humans, and (c) briefly address some problems and potential solutions with these novel therapies.

Age-associated chronic diseases require age-old medicine: role of chronic inflammation

Most chronic diseases--such as cancer, cardiovascular disease (CVD), Alzheimer disease, Parkinson disease, arthritis, diabetes and obesity--are becoming leading causes of disability and death all over the world. Some of the most common causes of these age-associated chronic diseases are lack of physical activity, poor nutrition, tobacco use, and excessive alcohol consumption. All the risk factors linked to these chronic diseases have been shown to up-regulate inflammation. Therefore, downregulation of inflammation-associated risk factors could prevent or delay these age-associated diseases. Although modern science has developed several drugs for treating chronic diseases, most of these drugs are enormously expensive and are associated with serious side effects and morbidity. In this review, we present evidence on how chronic inflammation leads to age-associated chronic disease. Furthermore, we discuss diet and lifestyle as solutions for age-associated chronic disease.

Protective effect of a novel peptide against methylmercury-induced toxicity in rat primary astrocytes

Methylmercury (MeHg) is an environmental neurotoxicant associated with aberrant central nervous system (CNS) functions. In this study, we examined the protective effect of a novel anti-inflammatory and cytoprotective nonapeptide, termed IIIM1, against MeHg-induced toxicity in cultured rat neonatal primary astrocytes. Astrocytes were pretreated for 66 h with 5 μg/ml IIIM1 (4.95 μM) followed by 6 h exposure to MeHg (5 μM). MeHg significantly increased F(2)-isoprostane generation, a lipid peroxidation biomarker of oxidative injury and this effect was significantly reduced upon pre-treatment with IIIM1. The MeHg-induced increase in levels of prostaglandin E(2) (PGE(2)), biomarkers of inflammatory responses, was also decreased in the peptide-treated cells. Mass spectrometry analysis revealed no chemical or binding interaction between MeHg and IIIM1, indicating that intracellular cytoprotective mechanism of action accounts for the neuroprotection rather than direct intracellular neutralization of the neurotoxicant with the peptide. These findings point to therapeutic potential for IIIM1 in a plethora of conditions associated with reactive oxygen species (ROS) generation. The implication of these findings may prove beneficial in designing new treatment modalities that efficiently suppress neurotoxicity, triggered not only by MeHg, but also by other metals and environmental agents, as well as chronic disease conditions that inherently increase reactive radical production and inflammatory signaling.

Autoimmunity in 2010

There is now growing evidence that autoimmunity is the common trait connecting multiple clinical phenotypes albeit differences in tissue specificity, pathogenetic mechanisms, and therapeutic approaches cannot be overlooked. Over the past years we witnessed a constant growth of the number of publications related to autoimmune diseases in peer-reviewed journals of the immunology area. Original data referred to factors from common injury pathways (i.e. T helper 17 cells, serum autoantibodies, or vitamin D) and specific diseases such as multiple sclerosis, systemic lupus erythematosus, and rheumatoid arthritis. As an example, the issue of a latitudinal gradient in the prevalence and incidence rates has been proposed for all autoimmune diseases and was recently coined as geoepidemiology to suggest new environmental triggers for tolerance breakdown. The present article is aimed at reviewing the articles that were published over the past year in the major autoimmunity and immunology journals.

Environmental pathways to autoimmune diseases: the cases of primary biliary cirrhosis and multiple sclerosis

The pathways leading to autoimmunity remain enigmatic despite numerous lines of experimental inquiry and epidemiological evidence. The mechanisms leading to the initiation and perpetuation of specific diseases such as primary biliary cirrhosis (PBC) or multiple sclerosis (MS) remain largely enigmatic, although it is established that a combination of genetic predisposition and environmental stimulation is required. The growing number of genome-wide association studies and the largely incomplete concordance for autoimmune diseases in monozygotic twins concur to support the role of the environment (including infectious agents and chemicals) in the breakdown of tolerance leading to autoimmunity through different mechanisms. In the present article we illustrate the current hypotheses related to an environmental impact on the onset of PBC and MS as two representative conditions investigated with complementary approaches. Indeed, while a role of post-translational antigen modifications has been proposed for MS, this field remain unexplored in PBC where, conversely, most evidence is gathered from geoepidemiology and experimental data on xenobiotics or infectious agents.

Novel peptides as potential treatment of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by a loss of immunologic tolerance, production of auto-antibodies, and inflammatory damage in multiple organs. We have tested the effect of anti-inflammatory peptide, a H2A histone fragment, termed IIIM1, on MRL/lpr mice, animal model of SLE. Oral administration of IIIM1 at early stage of disease caused reduction in proteinuria and serum anti-dsDNA antibodies. Starting the treatment at advanced stage of disease resulted in prolonged animal survival, decreased lymphadenosis and reduced levels of pathogenic or abnormal double negative CD4−CD8− cells and B220+ cells in lymph nodes and spleen. We discovered that IIIM1 induces the production of an additional peptide, a fragment of alpha-1-antitrypsin, termed UBE. A relatively low dose (1 µg/kg) of UBE reduced proteinuria and hematuria in MRL/lpr mice. The beneficial effect of the peptide was corroborated by histological examination. Furthermore a significant reduction in serum IL17, IL12 and anti dsDNA antibodies was observed in the UBE-treated mice. Isolated CD4 cells incubated with the peptide showed a similar cytokine profile. Decreased levels of double negative CD4−CD8− and B220+ cells were determined in lymph organs of UBE-treated animals. The beneficial effects of both UBE and IIIM1 suggest these peptides as potential drugs for SLE.

Staphylococcal enterotoxin A: a candidate for the amplification of physiological immunoregulatory responses in the gut

Staphylococcal enterotoxin A (SEA) is one of the bacterial products tested for modulation of unwanted immune responses. Of all the staphylococcal enterotoxins, SEA is the most potent stimulator of T cells. When administered orally, SEA acts as a superantigen (SA), producing unspecific stimulation of intra-epithelial lymphocytes (IELs) in the intestinal mucosa. This stimulation results in amplification of the normal local immunologic responses, which are mainly regulatory. This amplification is based on increased local production of IFN-γ by IELs, which acts on the nearby enterocytes. As a result, the enterocytes produce large amounts of tolerosomes, cellular corpuscles which detach themselves from the basal poles of the enterocytes and contain antigenic peptides that are conditioned to be interpreted as tolerogenic by the gut immune system. Tolerosomes are physiologically produced as a response to dietary peptides; it is already known that enterocytes posses the molecular mechanisms for processing peptides in a similar manner to lymphocytes. The fate of tolerosomes is not precisely known, but it seems that they merge with intestinal dendritic cells, conveying to them the information that orally administered peptides must be interpreted as tolerogens. SEA can stimulate this mechanism, thus favoring the development of tolerance to peptides/proteins administered subsequently via the oral route. This characteristic of SEA might be useful in therapy for regulating immune responses. The present paper reviews the current status of research regarding the impact of SEA on the enteric immune system and its potential use in the treatment of allergic and autoimmune diseases.

Anti-inflammatory effects of peptide fragments of H2A histone and Oryza Sativa Japonica protein

Anti-inflammatory drugs are often of limited use due to low efficacy and toxic effects. The present study describes the anti-inflammatory effects of a novel nonapeptide termed IIIM1, using the mouse hind paw edema as an experimental model of inflammation. Multiple prophylactic injections of IIIM1 resulted in a significant reduction in carrageenan-induced foot pad swelling, both in mice and rats. A single prophylactic treatment of the peptide caused the maximal effect at 7-9 days between the initial peptide treatment and the subsequent carrageenan injection. A reduced inflammatory reaction was observed in transgenic mice constitutively expressing the peptide. A marked decrease in oxidative burst was observed in activated peritoneal macrophages obtained from peptide-treated mice. Furthermore, the sera of IIIM1-treated mice caused a significant decrease in the oxidative burst of macrophages. In addition, the reduction of hind paw swelling in mice injected with the sera of IIIM1-treated mice strongly suggests the presence of a circulating inducible factor responsible for the anti-inflammatory effect of the peptide. Previous LC/MS/MS analysis revealed the presence of a new peptide, termed RA1, in the sera of IIIM1-treated mice. RA1 was identified as a fragment of the Oryza Sativa Japonica protein. The anti-inflammatory effect of RA1 as evidenced by the reduction in carrageenan-induced hind paw swelling corresponded with the decrease in the oxidative burst of macrophages treated in vitro with this peptide. In conclusion, both IIIM1 and RA1 represent potential agents for the efficient treatment of inflammatory diseases that are currently incurable using presently available drugs.