Induction of regulatory T cells by green tea polyphenol EGCG

The potential of EGCG in modulating the oral-gut axis microbiota for treating inflammatory bowel disease

Inflammatory bowel disease (IBD) is a recurrent chronic intestinal disorder that includes ulcerative colitis (UC) and Crohn's disease (CD). Its pathogenesis involves intricate interactions between pathogenic microorganisms, native intestinal microorganisms, and the intestinal immune system via the oral-gut axis. The strong correlation observed between oral diseases and IBD indicates the potential involvement of oral pathogenic microorganisms in IBD development. Consequently, therapeutic strategies targeting the proliferation, translocation, intestinal colonization and exacerbated intestinal inflammation of oral microorganisms within the oral-gut axis may partially alleviate IBD. Tea consumption has been identified as a contributing factor in reducing IBD, with epigallocatechin gallate (EGCG) being the primary bioactive compound used for IBD treatment. However, the precise mechanism by which EGCG mediates microbial crosstalk within the oral-gut axis remains unclear. In this review, we provide a comprehensive overview of the diverse oral microorganisms implicated in the pathogenesis of IBD and elucidate their colonization pathways and mechanisms. Subsequently, we investigated the antibacterial properties of EGCG and its potential to attenuate microbial translocation and colonization in the gut, emphasizing its role in attenuating exacerbations of IBD. We also elucidated the toxic and side effects of EGCG. Finally, we discuss current strategies for enhancing EGCG bioavailability and propose novel multi-targeted nano-delivery systems for the more efficacious management of IBD. This review elucidates the role and feasibility of EGCG-mediated modulation of the oral-gut axis microbiota in the management of IBD, contributing to a better understanding of the mechanism of action of EGCG in the treatment of IBD and the development of prospective treatment strategies.

Phytochemical analysis and immunomodulatory activities in vitro and in vivo of Aframomum melegueta K Schum seed extracts

Aframomum melegueta K Schum (A. melegueta), an herbaceous plant renowned for its medicinal seeds, was investigated for its potential immunomodulatory effects in vitro and in vivo using ethanolic and methanolic extracts. The immunomodulatory effect was evaluated by measuring antibody titers using the agglutination technique, while anti-inflammatory activity was assessed in a carrageenan-induced mouse paw edema model. In vitro immunomodulatory activity was measured by lysozyme release from neutrophils. Additionally, white blood cell counts were analyzed post-extracts treatment. The MTT assay was employed to determine cytotoxicity, and the biochemical parameters of liver toxicity were evaluated. Remarkably, both extracts exhibited a dose-dependent reduction in paw edema (p < 0.001), with the most significant reduction observed at 1 g/kg (78.13 and 74.27% for ethanolic and methanolic extracts, respectively). Neutrophil degranulation was significantly inhibited in a dose-dependent manner (p < 0.003), reaching maximal inhibition at 100 μg/mg (60.78 and 39.7% for ethanolic and methanolic extracts, respectively). In comparison to the control group, both antibody production and white blood cell counts were reduced. Neither of the extracts showcased any cytotoxicity or toxicity. These findings suggest that A. melegueta extracts exhibit immunosuppressive and anti-inflammatory activities due to the presence of various biomolecules.

Polyphenols: immunonutrients tipping the balance of immunometabolism in chronic diseases

Mounting evidence progressively appreciates the vital interplay between immunity and metabolism in a wide array of immunometabolic chronic disorders, both autoimmune and non-autoimmune mediated. The immune system regulates the functioning of cellular metabolism within organs like the brain, pancreas and/or adipose tissue by sensing and adapting to fluctuations in the microenvironment's nutrients, thereby reshaping metabolic pathways that greatly impact a pro- or anti-inflammatory immunophenotype. While it is agreed that the immune system relies on an adequate nutritional status to function properly, we are only just starting to understand how the supply of single or combined nutrients, all of them termed immunonutrients, can steer immune cells towards a less inflamed, tolerogenic immunophenotype. Polyphenols, a class of secondary metabolites abundant in Mediterranean foods, are pharmacologically active natural products with outstanding immunomodulatory actions. Upon binding to a range of receptors highly expressed in immune cells (e.g. AhR, RAR, RLR), they act in immunometabolic pathways through a mitochondria-centered multi-modal approach. First, polyphenols activate nutrient sensing via stress-response pathways, essential for immune responses. Second, they regulate mammalian target of rapamycin (mTOR)/AMP-activated protein kinase (AMPK) balance in immune cells and are well-tolerated caloric restriction mimetics. Third, polyphenols interfere with the assembly of NLR family pyrin domain containing 3 (NLRP3) in endoplasmic reticulum-mitochondria contact sites, inhibiting its activation while improving mitochondrial biogenesis and autophagosome-lysosome fusion. Finally, polyphenols impact chromatin remodeling and coordinates both epigenetic and metabolic reprogramming. This work moves beyond the well-documented antioxidant properties of polyphenols, offering new insights into the multifaceted nature of these compounds. It proposes a mechanistical appraisal on the regulatory pathways through which polyphenols modulate the immune response, thereby alleviating chronic low-grade inflammation. Furthermore, it draws parallels between pharmacological interventions and polyphenol-based immunonutrition in their modes of immunomodulation across a wide spectrum of socioeconomically impactful immunometabolic diseases such as Multiple Sclerosis, Diabetes (type 1 and 2) or even Alzheimer's disease. Lastly, it discusses the existing challenges that thwart the translation of polyphenols-based immunonutritional interventions into long-term clinical studies. Overcoming these limitations will undoubtedly pave the way for improving precision nutrition protocols and provide personalized guidance on tailored polyphenol-based immunonutrition plans.

Natural Immunomodulatory Agents as a Complementary Therapy for Poxviruses

Poxviruses target innate immunity mediators such as tumor necrosis factors, interleukins, interferons, complement, and chemokines. It also targets adaptive immunity such as CD4+ T cells, CD4+ T cells, and B cells. Emerging of the recent epidemic of monkeypox virus (MPXV), a zoonotic disease native to Central and Western Africa, besides the lack of permitted treatments for poxviruses infections, encouraged researchers to identify effective inhibitors to help in preventing and treating poxviruses infections. Natural bioactive components, particularly polyphenolics, are promising for creating powerful antioxidants, anti-inflammatory, immune-stimulating, and antiviral agents. As a result, they are potentially effective therapies for preventing and treating viral diseases, such as infections caused by poxviruses including the recent pandemic MPXV. Polyphenolics: rosmarinic acid, caffeic acid, resveratrol, quercitrin, myricitrin, gingerol, gallotannin, and propolis-benzofuran A, as well as isoquinoline alkaloids: galanthamine and thalimonine represent prospective antiviral agents against MPXV, they can inhibit MPXV and other poxviruses via targeting different viral elements including DNA Topoisomerase I (TOP1), Thymidine Kinase (TK), serine/threonine protein kinase (Ser/Thr kinase), and protein A48R. The bioactive extracts of different traditional plants including Guiera senegalensis, Larrea tridentata, Sarracenia purpurea, Kalanchoe pinnata (Lam.) Pers., Zingiber officinale Roscoe, Quercus infectoria, Rhus chinensis, Prunella vulgaris L., Salvia rosmarinus, and Origanum vulgare also can inhibit the growth of different poxviruses including MPXV, vaccinia virus (VACV), variola virus, buffalopox virus, fowlpox virus, and cowpox virus. There is an urgent need for additional molecular studies to identify and confirm the anti-poxviruses properties of various natural bioactive components, especially those that showed potent antiviral activity against other viruses.

The Role of Gluten in Food Products and Dietary Restriction: Exploring the Potential for Restoring Immune Tolerance

Wheat is extensively utilized in various processed foods due to unique proteins forming from the gluten network. The gluten network in food undergoes morphological and molecular structural changes during food processing, affecting the final quality and digestibility of the food. The present review introduces the formation of the gluten network and the role of gluten in the key steps of the production of several typical food products such as bread, pasta, and beer. Also, it summarizes the factors that affect the digestibility of gluten, considering that different processing conditions probably affect its structure and properties, contributing to an in-depth understanding of the digestion of gluten by the human body under various circumstances. Nevertheless, consumption of gluten protein may lead to the development of celiac disease (CD). The best way is theoretically proposed to prevent and treat CD by the inducement of oral tolerance, an immune non-response system formed by the interaction of oral food antigens with the intestinal immune system. This review proposes the restoration of oral tolerance in CD patients through adjunctive dietary therapy via gluten-encapsulated/modified dietary polyphenols. It will reduce the dietary restriction of gluten and help patients achieve a comprehensive dietary intake by better understanding the interactions between gluten and food-derived active products like polyphenols.

Protective effects of epigallocatechin gallate in the mice induced by chronic scrotal hyperthermia

One of the most common complications of chronic scrotal hyperthermia (SHT) is a serious disorder in the male reproductive system. The most important factor in the occurrence of these disorders is oxidative stress. Currently, we investigated the effects of epigallocatechin gallate (EGCG), as a highly potent antioxidant, against cells and tissue disorders in mice affected by chronic SHT. Fifty-six male adult NMRI mice were allocated into seven equal groups. Except the non-treated (Control) group, six other groups were exposed to heat stress. Two treated groups including Preventive and Curative received oral administration of EGCG (50 mg/kg/day) starting immediately before heat exposure and fifteen consecutive days after the end of the heat exposure, respectively. For each treated group, two subgroups including positive control (Pre/Cur + PC groups) and vehicle (Pre/Cur + vehicle groups) were considered. At the end of the study, sperm characteristics, testosterone levels, stereological parameters, apoptosis, oxidant state, and molecular assessments were performed. We found that the sperm parameters, testosterone levels, the numerical density of spermatogonia, primary spermatocytes, spermatids, sertoli, leydig cells, and seminiferous tubules, biochemical factors (except MDA), and expression of c-kit gene were significantly higher in the Preventive and Curative groups, especially in Preventive ones, compared to other groups (P < 0.05). This is while expression of HSP72 and NF-κβ genes, MDA levels, as well as density of apoptotic cells considerably decreased in both EGCG-treated groups compared to other groups and it was more pronounced in Preventive ones (P < 0.05). Generally, EGCG attenuated cellular and molecular disorders induced by heat stress in the testis and it was more pronounced in Preventive status.

Hyperbaric Oxygen in Combination with Epigallocatechin-3-Gallate Synergistically Enhance Recovery from Spinal Cord Injury in Rats

Spinal cord injury (SCI) following trauma is a devastating neurological event that can lead to loss of sensory and motor functions. However, the most effective measures to prevent the spread of damage are treatment measures in the early stages. Currently, we investigated the combined effects of hyperbaric oxygen (HBO) along with epigallocatechin-3-gallate (EGCG) in the recovery of SCI in rats. Ninety male mature Sprague-Dawley rats were randomly planned into five equal groups (n = 18). In addition to sham group that only underwent laminectomy, SCI rats were allocated into 4 groups as follows: control group; HBO group; EGCG group; and HBO + EGCG group. Tissue samples at the lesion site were obtained for stereological, immunohistochemical, biochemical, and molecular evaluation. In addition, behavioral tests were performed to assess of neurological functions. The finding indicated that the stereological parameters, antioxidant factors (CAT, GSH, and SOD), IL-10 gene expression levels and neurological functions were considerably increased in the treatment groups in comparison with control group, and these changes were more obvious in the HBO + EGCG group (P < 0.05). On the other hand, we observed that the density of apoptotic cells and gliosis, the biochemical levels of MDA and the expression levels of inflammatory genes (TNF-α and IL-1β) in the treatment groups, especially the HBO + EGCG group, were considerably reduced in comparison with control group (P < 0.05). We conclude that co-administration of HBO and EGCG has a synergistic neuroprotective effects in animals undergoing SCI.

Chlorella vulgaris Modulates Gut Microbiota and Induces Regulatory T Cells to Alleviate Colitis in Mice

Chlorella vulgaris (C. vulgaris) is unicellular green algae consumed worldwide as a functional food. The immune stimulatory function of C. vulgaris is known; however, no study has elucidated its immune regulatory potential and associated microbiome modulation. In the current study, we aimed to validate the immune regulatory role of C. vulgaris mediated through two mechanisms. Initially, we assessed its ability to promote the expansion of the regulatory T cell (Treg) population. Subsequently, we investigated its impact on gut microbiota composition and associated metabolites. The supplementation of C. vulgaris altered the gut microbiota composition, accompanied by increased short-chain fatty acid (SCFAs) production in mice at homeostasis. We later used C. vulgaris in the treatment of a DSS-induced colitis model. C. vulgaris intervention alleviated the pathological symptom of colitis in mice, with a corresponding increase in Treg levels. As C. vulgaris is a safe and widely used food supplement, it can be a feasible strategy to instigate cross-talk between the host immune system and the intestinal flora for the effective management of inflammatory bowel disease (IBD).

The multifaceted nature of IL-10: regulation, role in immunological homeostasis and its relevance to cancer, COVID-19 and post-COVID conditions

Interleukin-10 (IL-10) is a pleiotropic cytokine that has a fundamental role in modulating inflammation and in maintaining cell homeostasis. It primarily acts as an anti-inflammatory cytokine, protecting the body from an uncontrolled immune response, mostly through the Jak1/Tyk2 and STAT3 signaling pathway. On the other hand, IL-10 can also have immunostimulating functions under certain conditions. Given the pivotal role of IL-10 in immune modulation, this cytokine could have relevant implications in pathologies characterized by hyperinflammatory state, such as cancer, or infectious diseases as in the case of COVID-19 and Post-COVID-19 syndrome. Recent evidence proposed IL-10 as a predictor of severity and mortality for patients with acute or post-acute SARS-CoV-2 infection. In this context, IL-10 can act as an endogenous danger signal, released by tissues undergoing damage in an attempt to protect the organism from harmful hyperinflammation. Pharmacological strategies aimed to potentiate or restore IL-10 immunomodulatory action may represent novel promising avenues to counteract cytokine storm arising from hyperinflammation and effectively mitigate severe complications. Natural bioactive compounds, derived from terrestrial or marine photosynthetic organisms and able to increase IL-10 expression, could represent a useful prevention strategy to curb inflammation through IL-10 elevation and will be discussed here. However, the multifaceted nature of IL-10 has to be taken into account in the attempts to modulate its levels.

Neuron-immunity communication: mechanism of neuroprotective effects in EGCG

Epigallocatechin gallate (EGCG), a naturally occurring active ingredient unique to tea, has been shown to have neuroprotective potential. There is growing evidence of its potential advantages in the prevention and treatment of neuroinflammation, neurodegenerative diseases, and neurological damage. Neuroimmune communication is an important physiological mechanism in neurological diseases, including immune cell activation and response, cytokine delivery. EGCG shows great neuroprotective potential by modulating signals related to autoimmune response and improving communication between the nervous system and the immune system, effectively reducing the inflammatory state and neurological function. During neuroimmune communication, EGCG promotes the secretion of neurotrophic factors into the repair of damaged neurons, improves intestinal microenvironmental homeostasis, and ameliorates pathological phenotypes through molecular and cellular mechanisms related to the brain-gut axis. Here, we discuss the molecular and cellular mechanisms of inflammatory signaling exchange involving neuroimmune communication. We further emphasize that the neuroprotective role of EGCG is dependent on the modulatory role between immunity and neurology in neurologically related diseases.

Opportunities and challenges of polyphenols and polysaccharides for type 1 diabetes intervention

Type 1 diabetes (T1D) is an autoimmune disorder characterized by the destruction of insulin-producing pancreatic β cell. It contributes to high mortality, frequent diabetic complications, poor quality of life in patients and also puts a significant economic burden on health care systems. Therefore, the development of new therapeutic strategies is urgently needed. Recently, certain dietary compounds with potential applications in food industry, particularly polyphenols and polysaccharides, have gained increasing attention with their prominent anti-diabetic effects on T1D by modulating β cell function, the gut microbiota and/or the immune system. In this review, we critically discuss the recent findings of several dietary polyphenols and polysaccharides with the potential to protect against T1D and the underlying anti-diabetic mechanisms. More importantly, we highlight the current trends, major issues, and future directions of industrial production of polyphenols- and polysaccharides-based functional foods for preventing or delaying T1D.

Non-Celiac Gluten Sensitivity and Protective Role of Dietary Polyphenols

Pathogenetically characterized by the absence of celiac disease and wheat allergy, non-celiac gluten sensitivity (NCGS) is a clinical entity triggered by the consumption of gluten-containing foods that relieved by a gluten-free diet. Since it is very difficult to maintain a complete gluten-free diet, there is a high interest in discovering alternative strategies aimed at reducing gluten concentration or mitigating its toxic effects. Plant-based dietary models are usually rich in bioactive compounds, such as polyphenols, recognized to prevent, delay, or even reverse chronic diseases, including intestinal disorders. However, research on the role of polyphenols in mitigating the toxicity of gluten-containing foods is currently limited. We address the metabolic fate of dietary polyphenols, both as free and bound macromolecule-linked forms, with particular reference to the gastrointestinal compartment, where the concentration of polyphenols can reach high levels. We analyze the potential targets of polyphenols including the gluten peptide bioavailability, the dysfunction of the intestinal epithelial barrier, intestinal immune response, oxidative stress and inflammation, and dysbiosis. Overall, this review provides an updated overview of the effects of polyphenols as possible dietary strategies to counteract the toxic effects of gluten, potentially resulting in the improved quality of life of patients with gluten-related disorders.

Green Tea (Camellia sinensis): A Review of Its Phytochemistry, Pharmacology, and Toxicology

Objectives Green tea (Camellia sinensis) is a kind of unfermented tea that retains the natural substance in fresh leaves to a great extent. It is regarded as the second most popular drink in the world besides water. In this paper, the phytochemistry, pharmacology, and toxicology of green tea are reviewed systematically and comprehensively. Key findings Green tea has been demonstrated to be good for human health. Nowadays, multiple pharmacologically active components have been isolated and identified from green tea, including tea polyphenols, alkaloids, amino acids, polysaccharides, and volatile components. Recent studies have demonstrated that green tea shows versatile pharmacological activities, such as antioxidant, anticancer, hypoglycemic, antibacterial, antiviral, and neuroprotective. Studies on the toxic effects of green tea extract and its main ingredients have also raised concerns including hepatotoxicity and DNA damage. Summary Green tea can be used to assist the treatment of diabetes, Alzheimer’s disease, oral cancer, and dermatitis. Consequently, green tea has shown promising practical prospects in health care and disease prevention.

Treg/Th17 Ratio Regulation May Play an Important Role in Epigallocatechin-3-Gallate-Mediated Attenuation of Increased Afterload-Induced Cardiac Hypertrophy

ABSTRACT

The aim of this study was to investigate whether Treg/Th17 ratio regulation plays an important role in epigallocatechin-3-gallate (EGCG) in attenuating increased afterload-induced cardiac hypertrophy. Three-month-old male C57BL/6 mice were divided into sham + vehicle, abdominal aortic constriction (AAC) + vehicle, and AAC + EGCG groups. Intraperitoneal EGCG (50 mg/kg/d) administration was conducted. Cardiac structure and function were examined by ultrasonography. Pathology was examined by hematoxylin and eosin staining, wheat germ agglutinin staining, and Masson's trichome staining. T-lymphocyte subtypes were analyzed using immunofluorescence and flow cytometry assays. Ultrasonography showed that the ventricular wall in the AAC + vehicle group was thicker than that in the sham + vehicle group (P < 0.05). Hematoxylin and eosin staining revealed cardiomyocyte hypertrophy accompanied by a small amount of inflammatory cell infiltration in the AAC + vehicle group. The results of wheat germ agglutinin staining demonstrated the presence of hypertrophic cardiomyocytes in the AAC + vehicle group (P < 0.01). Masson's trichome staining showed cardiac fibrosis in the AAC + vehicle group, and the immunofluorescence assay revealed infiltration of CD4+ cells in both AAC + vehicle and AAC + EGCG groups. Splenic flow cytometry showed a significant increase in the proportion of Treg cells in the AAC + EGCG group (P < 0.05). The proportion of Th17 cells in the AAC + vehicle group was significantly higher than that in the sham + vehicle group (P < 0.05). In conclusion, changes in the Treg/Th17 ratio are associated with the occurrence of myocardial hypertrophy caused by increased afterload. Moreover, regulation of the Treg/Th17 ratio by EGCG may play an important role in the attenuation of myocardial hypertrophy.

DNA Methyltransferase 3b Accelerates the Process of Atherosclerosis

Background

DNA methylation plays a key role in establishing cell type-specific gene expression profiles and patterns in atherosclerosis. The underlying mechanism remains unclear. Previous studies have shown that DNA methyltransferase 3b (DNMT3b) may play an important role in atherosclerosis. This study aimed to establish the regulatory role of DNMT3b in the development of atherosclerosis.

Methods

We constructed a viral vector carrying Dnmt3b shRNA to transduce ApoE-/- mice. Meanwhile, healthy human peripheral blood Treg cells were treated with inhibitor of DNMT3b (AZA and EGCG) or transduced with DNMT3b shRNA.

Results

It showed that Dnmt3b silencing attenuated atherosclerosis, including decreased lesion size and macrophage content and increased collagen and smooth muscle cells content in ApoE-/- mice. To further investigate the possible mechanisms, combined with previous studies by our group, we showed that Foxp3-TSDR methylation level was significantly reduced Foxp3 expression and peripheral blood Treg levels were significantly increased by Dnmt3b shRNA vector transduction in animals committed to western diet for 12 and 18 weeks. Consistently, inhibition of DNMT3b (AZA and EGCG) decreased the expression levels of DNMT3b, which can increase the expression levels of FOXP3, and increase the levels of TGF-β and IL-10 and decrease the levels of IL-β and IFN-γ. After transduction with DNMT3b shRNA, the effect was more obvious.

Conclusions

DNMT3b accelerated atherosclerosis, and may be associated with FOXP3 hypermethylation status in regulatory T cells.

Machine Learning of ZnO Interaction with Immunoglobulins and Blood Proteins in Medicine

Toxoplasmosis is a zoonotic illness caused by Toxoplasma gondii. Those with a normal immune system normally recover without treatment. Immunocompromised individuals and pregnant women must be treated regularly. Toxoplasmosis is a serious illness that may reactivate in immunocompromised patients. A retrospective study using machine learning of toxoplasmosis patients at Government Fever Hospital in Gorantla, Guntur, India, included 25 women, eight of whom were pregnant. These included sex, age, symptoms and side effects, pregnancy, ophthalmic, and antitoxoplasmosis titers, and treatment regimens. Protease mobility and specific activity were increased in toxoplasmosis-infected women's sera, although not significantly (p=0.05). However, there was no discernible decline. The impacts of nanoparticle impact demonstrated a 52.24 percent drop in compound concentration in the presence of zinc nanoparticles, whereas the effect of ZnO nanoparticles was 51.37 percent. Zinc nanoparticles lowered IgA, IgG, and IgM levels in the eye.

Polyphenols Targeting MAPK Mediated Oxidative Stress and Inflammation in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic, autoimmune disorder, predominantly symmetric, which causes joint inflammation, cartilage degeneration and bone erosion, resulting in deformity and the loss of physical function. Although the management of RA has steadily improved, the pathophysiological mechanism is incompletely elucidated, and therapeutic options are still limited. Due to shortcomings in the efficacy or safety profiles of conventional RA therapies, therapeutic alternatives have been considered. Therefore, natural extracts containing polyphenolic compounds can become promising adjuvant agents for RA global management, due to their antioxidant, anti-inflammatory and apoptotic properties. Polyphenols can regulate intracellular signaling pathways in RA and can generate different immune responses through some key factors (i.e., MAPK, interleukins (ILs 1 and 6), tumor necrosis factor (TNF), nuclear factor light k chain promoter of activated receptor (NF-κB), and c-Jun N-terminal kinases (JNK)). The critical function of the Toll like-receptor (TLR)-dependent mitogen-activating protein kinase (MAPK) signaling pathway in mediating the pathogenic characteristics of RA has been briefly discussed. Oxidative stress can trigger a change in transcription factors, which leads to the different expression of some genes involved in the inflammatory process. This review aims to provide a comprehensive perspective on the efficacy of polyphenols in mitigating RA by inhibiting signaling pathways, suggesting future research perspectives in order to validate their use.

Resveratrol, EGCG and Vitamins Modulate Activated T Lymphocytes

Vitamins and bioactives, which are constituents of the food chain, modulate T lymphocyte proliferation and differentiation, antibody production, and prevent inflammation and autoimmunity. We investigated the effects of vitamins (vitamin A (VA), D (VD), E (VE)) and bioactives (i.e., resveratrol (Res), epigallocatechin-3-gallate (EGCG)) on the adaptive immune response, as well as their synergistic or antagonistic interactions. Freshly isolated T lymphocytes from healthy individuals were activated with anti-CD3/CD28 antibodies for 4–5 days in the presence of bioactives and were analyzed by cytofluorometry. Interleukins, cytokines, and chemokines were measured by multiple ELISA. Gene expression was measured by quantitative RT-PCR. Res and EGCG increased CD4 surface intensity. EGCG led to an increased proportion of CD8⁺ lymphocytes. Anti-CD3/CD28 activation induced exuberant secretion of interleukins and cytokines by T lymphocyte subsets. VD strongly enhanced T_h2 cytokines (e.g., IL-5, IL-13), whereas Res and EGCG favored secretion of T_h1 cytokines (e.g., IL-2, INF-γ). Res and VD mutually influenced cytokine production, but VD dominated the cytokine secretion pattern. The substances changed gene expression of interleukins and cytokines in a similar way as they did secretion. Collectively, VD strongly modulated cytokine and interleukin production and favored T_h2 functions. Resveratrol and EGCG promoted the T_h1 response. VA and VE had only a marginal effect, but they altered both T_h1 and T_h2 response. In vivo, bioactives might therefore interact with vitamins and support the outcome and extent of the adaptive immune response.

The Kynurenine Pathway-New Linkage between Innate and Adaptive Immunity in Autoimmune Endocrinopathies

The kynurenine pathway (KP) is highly regulated in the immune system, where it promotes immunosuppression in response to infection or inflammation. Indoleamine 2,3-dioxygenase 1 (IDO1), the main enzyme of KP, has a broad spectrum of activity on immune cells regulation, controlling the balance between stimulation and suppression of the immune system at sites of local inflammation, relevant to a wide range of autoimmune and inflammatory diseases. Various autoimmune diseases, among them endocrinopathies, have been identified to date, but despite significant progress in their diagnosis and treatment, they are still associated with significant complications, morbidity, and mortality. The precise cellular and molecular mechanisms leading to the onset and development of autoimmune disease remain poorly clarified so far. In breaking of tolerance, the cells of the innate immunity provide a decisive microenvironment that regulates immune cells’ differentiation, leading to activation of adaptive immunity. The current review provided a comprehensive presentation of the known role of IDO1 and KP activation in the regulation of the innate and adaptive arms of the immune system. Significant attention has been paid to the immunoregulatory role of IDO1 in the most prevalent, organ-specific autoimmune endocrinopathies—type 1 diabetes mellitus (T1DM) and autoimmune thyroiditis.

Molecular mechanisms and applications of tea polyphenols: A narrative review

Tea is a worldwide popular drink with high nutritional and medicinal values as it is rich in nutrients, such as polyphenols, amino acids, vitamins, glycosides, and so on. Among them, tea polyphenols (TPs) are the current research hotspot. TPs are known to have multiple biological activities such as anti-oxidation, anti-tumor, anti-inflammation, anti-bacteria, lowering lipid, and liver protection. By reviewing a large number of literatures, we explained the mechanism of TPs exerting biological activity and a wide range of applications. We also discussed the deficiencies and development potential of TPs, in order to provide theoretical reference and scientific basis for the subsequent development and utilization of TPs. PRACTICAL APPLICATIONS: We summarized the bioactivity mechanisms of TPs in anti-tumor, anti-oxidation, antibacterial, anti-inflammatory, lipid-lowering, and liver protection, focused on its application fields in food and medicine, and discussed the deficiency and development potential of current research on TPs, so as to provide a certain convenient way for scholars studying TPs. It is expected to contribute to the subsequent discovery of biological activity and the broadening of the field of TPs.

Epigenetic linkage of systemic lupus erythematosus and nutrition

The term "epigenetics" refers to a series of meiotically/mitotically inheritable alterations in gene expression, related to environmental factors, without disruption on DNA sequences of bases. Recently, the pathophysiology of autoimmune diseases (ADs) has been closely linked to epigenetic modifications. Actually, epigenetic mechanisms can modulate gene expression or repression of targeted cells and tissues involved in autoimmune/inflammatory conditions acting as keys effectors in regulation of adaptive and innate responses. ADs, as systemic lupus erythematosus (SLE), a rare disease that still lacks effective treatment, is characterized by epigenetic marks in affected cells.Taking into account that epigenetic mechanisms have been proposed as a winning strategy in the search of new more specific and personalized therapeutics agents. Thus, pharmacology and pharmacoepigenetic studies about epigenetic regulations of ADs may provide novel individualized therapies. Focussing in possible implicated factors on development and predisposition of SLE, diet is feasibly one of the most important factors since it is linked directly to epigenetic alterations and these epigenetic changes may augment or diminish the risk of SLE. Nevertheless, several studies have guaranteed that dietary therapy could be a promise to SLE patients via prophylactic actions deprived of side effects of pharmacology, decreasing co-morbidities and improving lifestyle of SLE sufferers.Herein, we review and discuss the cross-link between epigenetic mechanisms on SLE predisposition and development, as well as the influence of dietary factors on regulation epigenetic modifications that would eventually make a positive impact on SLE patients.

Roles and Mechanisms of DNA Methylation in Vascular Aging and Related Diseases

Vascular aging is a pivotal risk factor promoting vascular dysfunction, the development and progression of vascular aging-related diseases. The structure and function of endothelial cells (ECs), vascular smooth muscle cells (VSMCs), fibroblasts, and macrophages are disrupted during the aging process, causing vascular cell senescence as well as vascular dysfunction. DNA methylation, an epigenetic mechanism, involves the alteration of gene transcription without changing the DNA sequence. It is a dynamically reversible process modulated by methyltransferases and demethyltransferases. Emerging evidence reveals that DNA methylation is implicated in the vascular aging process and plays a central role in regulating vascular aging-related diseases. In this review, we seek to clarify the mechanisms of DNA methylation in modulating ECs, VSMCs, fibroblasts, and macrophages functions and primarily focus on the connection between DNA methylation and vascular aging-related diseases. Therefore, we represent many vascular aging-related genes which are modulated by DNA methylation. Besides, we concentrate on the potential clinical application of DNA methylation to serve as a reliable diagnostic tool and DNA methylation-based therapeutic drugs for vascular aging-related diseases.

Immunomodulatory Effects of Green Tea Polyphenols

Green tea and its bioactive components, especially polyphenols, possess many health-promoting and disease-preventing benefits, especially anti-inflammatory, antioxidant, anticancer, and metabolic modulation effects with multi-target modes of action. However, the effect of tea polyphenols on immune function has not been well studied. Moreover, the underlying cellular and molecular mechanisms mediating immunoregulation are not well understood. This review summarizes the recent studies on the immune-potentiating effects and corresponding mechanisms of tea polyphenols, especially the main components of (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin-3-gallate (ECG). In addition, the benefits towards immune-related diseases, such as autoimmune diseases, cutaneous-related immune diseases, and obesity-related immune diseases, have been discussed.

Tremella fuciformis Polysaccharides Inhibited Colonic Inflammation in Dextran Sulfate Sodium-Treated Mice via Foxp3+ T Cells, Gut Microbiota, and Bacterial Metabolites

Tremella fuciformis is an edible medicinal mushroom, and its polysaccharide components are found to confer various health benefits. This study identified the protective effects of polysaccharides of Tremella fuciformis (TPs) against dextran sulfate sodium (DSS)-induced colitis in mice. High dose of TPs (HTPs) could prevent the colon from shortening, reduce activity of colonic myeloperoxidase and serum diamine oxidase (DAO), decrease the concentration of D-lactate, and alleviate the colonic tissue damage in colitic mice. HTPs treatment stimulated Foxp3+T cells, and promoted the production of anti-inflammatory cytokines whereas it reduced the production of pro-inflammatory and the portion of immunoglobulin A (IgA)-coated bacteria, which was related to modulation of immune responses. 16S rRNA sequencing analysis showed that TPs could significantly increase gut community diversity, and restore the relative abundances of Lactobacillus, Odoribacter, Helicobacter, Ruminococcaceae, and Marinifilaceae. According to metabolomic analysis, HTPs induced specific microbial metabolites akin to that in normal mice. Tyrosine biosynthesis, tryptophan metabolism, and bile acid metabolism were influenced in the HTPs group compared with those in the DSS group. HTPs could alleviate DSS-induced colitis by immunoregulation and restored the gut microbiota and microbial metabolites. The results indicated that HTPs have potential to be developed as a food supplement to ameliorate intestinal diseases.

Immunomodulatory Effects of Dietary Polyphenols

Functional and nutraceutical foods provide an alternative way to improve immune function to aid in the management of various diseases. Traditionally, many medicinal products have been derived from natural compounds with healing properties. With the development of research into nutraceuticals, it is becoming apparent that many of the beneficial properties of these compounds are at least partly due to the presence of polyphenols. There is evidence that dietary polyphenols can influence dendritic cells, have an immunomodulatory effect on macrophages, increase proliferation of B cells, T cells and suppress Type 1 T helper (Th1), Th2, Th17 and Th9 cells. Polyphenols reduce inflammation by suppressing the pro-inflammatory cytokines in inflammatory bowel disease by inducing Treg cells in the intestine, inhibition of tumor necrosis factor-alpha (TNF-α) and induction of apoptosis, decreasing DNA damage. Polyphenols have a potential role in prevention/treatment of auto-immune diseases like type 1 diabetes, rheumatoid arthritis and multiple sclerosis by regulating signaling pathways, suppressing inflammation and limiting demyelination. In addition, polyphenols cause immunomodulatory effects against allergic reaction and autoimmune disease by inhibition of autoimmune T cell proliferation and downregulation of pro-inflammatory cytokines (interleukin-6 (IL-6), IL-1, interferon-γ (IFN-γ)). Herein, we summarize the immunomodulatory effects of polyphenols and the underlying mechanisms involved in the stimulation of immune responses.

Cancer Related Anemia: An Integrated Multitarget Approach and Lifestyle Interventions

Cancer is often accompanied by worsening of the patient's iron profile, and the resulting anemia could be a factor that negatively impacts antineoplastic treatment efficacy and patient survival. The first line of therapy is usually based on oral or intravenous iron supplementation; however, many patients remain anemic and do not respond. The key might lie in the pathogenesis of the anemia itself. Cancer-related anemia (CRA) is characterized by a decreased circulating serum iron concentration and transferrin saturation despite ample iron stores, pointing to a more complex problem related to iron homeostatic regulation and additional factors such as chronic inflammatory status. This review explores our current understanding of iron homeostasis in cancer, shedding light on the modulatory role of hepcidin in intestinal iron absorption, iron recycling, mobilization from liver deposits, and inducible regulators by infections and inflammation. The underlying relationship between CRA and systemic low-grade inflammation will be discussed, and an integrated multitarget approach based on nutrition and exercise to improve iron utilization by reducing low-grade inflammation, modulating the immune response, and supporting antioxidant mechanisms will also be proposed. Indeed, a Mediterranean-based diet, nutritional supplements and exercise are suggested as potential individualized strategies and as a complementary approach to conventional CRA therapy.

Green Tea Polyphenol-Sensitive Calcium Signaling in Immune T Cell Function

Polyphenol compounds found in green tea have a great therapeutic potential to influence multiple human diseases including malignancy and inflammation. In this mini review, we describe effects of green tea and the most important component EGCG in malignancy and inflammation. We focus on cellular mechanisms involved in the modification of T cell function by green tea polyphenol EGCG. The case is made that EGCG downregulates calcium channel activity by influencing miRNAs regulating expression of the channel at the post-transcriptional level.

Dietary molecules and experimental evidence of epigenetic influence in cancer chemoprevention: An insight

The world-wide rate of incidence of cancer disease has been only modestly contested by the past and current preventive and interventional strategies. Hence, the global effort towards novel ideas to contain the disease still continues. Constituents of human diets have in recent years emerged as key regulators of carcinogenesis, with studies reporting their inhibitory potential against all the three stages vis-a-vis initiation, promotion and progression. Unlike drugs which usually act on single targets, these dietary factors have an advantage of multi-targeted effects and pleiotropic action mechanisms, which are effective against cancer that manifest as a micro-evolutionary and multi-factorial disease. Since most of the cellular targets have been identified and their consumption considered relatively safe, these diet-derived agents often appear as molecules of interest in repurposing strategies. Currently, many of these molecules are being investigated for their ability to influence the aberrant alterations in cell's epigenome for epigenetic therapy against cancer. Targeting the epigenetic regulators is a new paradigm in cancer chemoprevention which acts to reverse the warped-up epigenetic alterations in a cancer cell, thereby directing it towards a normal phenotype. In this review, we discuss the significance of dietary factors and natural products as chemopreventive agents. Further, we corroborate the experimental evidence from existing literature, reflecting the ability of a series of such molecules to act as epigenetic modifiers in cancer cells, by interfering with molecular events that map the epigenetic imprints such as DNA methylation, histone acetylation and non-coding RNA mediated gene regulation.

From Suppressor T cells to Regulatory T cells: How the Journey That Began with the Discovery of the Toxic Effects of TCDD Led to Better Understanding of the Role of AhR in Immunoregulation

Aryl hydrocarbon receptor (AhR) was identified in the early 1970s as a receptor for the ubiquitous environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin), which is a member of halogenated aromatic hydrocarbons (HAHs). TCDD was found to be highly toxic to the immune system, causing thymic involution and suppression of a variety of T and B cell responses. The fact that environmental chemicals cause immunosuppression led to the emergence of a new field, immunotoxicology. While studies carried out in early 1980s demonstrated that TCDD induces suppressor T cells that attenuate the immune response to antigens, further studies on these cells were abandoned due to a lack of specific markers to identify such cells. Thus, it was not until 2001 when FoxP3 was identified as a master regulator of Regulatory T cells (Tregs) that the effect of AhR activation on immunoregulation was rekindled. The more recent research on AhR has led to the emergence of AhR as not only an environmental sensor but also as a key regulator of immune response, especially the differentiation of Tregs vs. Th17 cells, by a variety of endogenous, microbial, dietary, and environmental ligands. This review not only discusses how the role of AhR emerged from it being an environmental sensor to become a key immunoregulator, but also confers the identification of new AhR ligands, which are providing novel insights into the mechanisms of Treg vs. Th17 differentiation. Lastly, we discuss how AhR ligands can trigger epigenetic pathways, which may provide new opportunities to regulate inflammation and treat autoimmune diseases.

The immunoregulatory function of polyphenols: implications in cancer immunity

Polyphenols have demonstrated several potential biological activities, notably antitumoral activity dependent on immune function. In the present review, we describe studies that investigated antitumor immune responses influenced by polyphenols and the mechanisms by which polyphenols improve the immune response. We also discuss the limitations in related areas, especially unexplored areas of research, and next steps required to develop a therapeutic approach utilizing polyphenols in oncology.

Preclinical Pharmacological Activities of Epigallocatechin-3-gallate in Signaling Pathways: An Update on Cancer

Epigallocatechin gallate (EGCG) is the main bioactive component of catechins predominantly present in svarious types of teas. EGCG is well known for a wide spectrum of biological activity as an anti-oxidative, anti-inflammatory, and anti-tumor agent. The effect of EGCG on cell death mechanisms via the induction of apoptosis, necrosis, and autophagy has been documented. Moreover, its anti-proliferative and chemopreventive action has been demonstrated in many cancer cell lines. It was also involved in the modulation of cyclooxygenase-2, in oxidative stress and inflammation of different cell processes. EGCG has been reported as a promising target for plasma membrane proteins, such as epidermal growth factor receptor (EGFR). In addition, it has been demonstrated a mechanism of action relying on the inhibition of ERK1/2, p38 MAPK, NF-κB, and vascular endothelial growth factor (VEGF). EGCG and its derivatives were used in proteasome inhibition and they were involved in epigenetic mechanisms. In summary, EGCG is the most predominant and bioactive constituent of teas and it has a pivotal role in cancer prevention. Its preclinical pharmacological activities are associated with complex molecular mechanisms that involve numerous signaling pathways.

Lactobacillus casei-fermented blueberry pomace augments sIgA production in high-fat diet mice by improving intestinal microbiota

Intestinal secretory immunoglobulin A (sIgA)-improving function of Lactobacillus casei-fermented blueberry pomace (FBP) was investigated in this study.

Reversal of phosphate-induced ORAI1 expression, store-operated Ca2+ entry and osteogenic signaling by MgCl2 in human aortic smooth muscle cells

In chronic kidney disease, renal phosphate retention leads to hyperphosphatemia with subsequent vascular osteogenic signaling and calcification. Osteogenic signaling involves up-regulation of the transcription factors CBFA1, MSX2, and SOX9, as well as alkaline phosphatase (ALP), an enzyme stimulating calcification by degrading the calcification inhibitor pyrophosphate. Stimulation of osteogenic signaling and calcification by phosphate donor β-glycerophosphate in human aortic smooth muscle cells (HAoSMCs) is attenuated by MgCl₂, an effect mimicked by Ca²⁺-sensing receptor agonist GdCl₃. Most recent observations revealed that the effect of β-glycerophosphate on osteogenic signaling requires ORAI1, a Ca²⁺-channel accomplishing store-operated Ca²⁺-entry (SOCE), which is stimulated by Ca²⁺-sensor STIM1. The present study explored whether ORAI1 and/or STIM1 expression and, thus, SOCE and osteogenic signaling in HAoSMCs are sensitive to MgCl₂ and/or GdCl₃. To this end, transcript levels were estimated using q-RT-PCR, protein abundance with western blotting, cytosolic Ca²⁺-concentration ([Ca²⁺]_i) by Fura-2-fluorescence, and SOCE from increase of [Ca²⁺]_i following re-addition of extracellular Ca²⁺ after store depletion with thapsigargin (1  μM). As a result, 24 h exposure to β-glycerophosphate (2 mM) significantly enhanced transcript levels of ORAI1 and STIM1 as well as SOCE, effects significantly blunted or virtually abrogated by 1.5 mM MgCl₂ and by 50  μM GdCl₃. In conclusion, MgCl₂ and GdCl₃ are powerful inhibitors of ORAI1 and STIM1 expression and store-operated Ca²⁺-entry, effects affecting osteogenic signalling in vascular smooth muscle cells.

Polyphenolic Extract (PE) from Olive Oil Exerts a Potent Immunomodulatory Effect and Prevents Graft-versus-Host Disease in a Mouse Model

Polyphenols are a group of chemical substances found in plants, with immunomodulatory, antiproliferative, and anti-inflammatory properties that might be useful in the prophylaxis and treatment of graft-versus-host disease (GVHD). Polyphenolic extract (PE) obtained from extra virgin olive oil (EVOO) decreased the activation and proliferation of activated T cells. In addition, a decreased production of proinflammatory cytokines was observed upon exposure to PE. Western blot assays showed a marked inhibition of Akt phosphorylation and nuclear translocation of NF-κB in activated T cells. In a murine model of acute GVHD, we observed that mice that received a diet supplemented in PE (600 ppm) presented a higher survival rate and lower risk of developing GVHD when compared with the group that received a control diet. Histopathologic examination showed a significantly lower gut involvement in mice receiving PE, with a decrease in proinflammatory cytokines (IL-2, IL-17, and TNF-α) in serum and the reestablishment of butyrate concentration in the gut. In conclusion, PE obtained from EVOO exerted a potent immunomodulatory effect, reducing the activation and proliferation of activated T cells and the production of proinflammatory cytokines. In a murine model of acute GVHD, a PE-supplemented diet reduced the incidence and severity of the disease and increased survival after transplantation.

Elevated Methylation of FOXP3 (Forkhead Box P3)-TSDR (Regulatory T-Cell-Specific Demethylated Region) Is Associated With Increased Risk for Adverse Outcomes in Patients With Acute Coronary Syndrome

Demethylation of the forkhead box P3 (FOXP3) corresponds with stability of FOXP3 expression and immunosuppressive function of regulatory T cells (Tregs). Previous studies have demonstrated that reduction in Tregs is associated with acute coronary syndrome (ACS). The aim of this study was to establish the relationship between methylation level of FOXP3-TSDR (Treg-specific demethylated region) and clinical outcomes of ACS. We first evaluated the prognostic significance of methylation levels of FOXP3-TSDR in patients with ACS (n=171). Then, we explored the possible mechanism of methylation levels of FOXP3-TSDR on clinical outcomes of ACS in vivo. We analyzed methylation of FOXP3-TSDR, percentage of Tregs in total peripheral blood, and atherosclerotic lesions in aortic root in ApoE^-/- mice (n=48; 6 groups). During the follow-up of 4.5±0.8 years, survival free of major adverse cardiovascular events was the lowest in the highest tertile of FOXP3-TSDR methylation (log-rank P=0.004). Multivariate analysis showed that FOXP3-TSDR methylation was independently and positively related to major adverse cardiovascular events (adjusted hazard ratio, 2.13; 95% CI, 1.21-3.75; P=0.009). We observed a duration-dependent increase in the methylation levels of FOXP3-TSDR in mice fed with Western diet at a period of 0, 3, 6, 9, 12, and 15 weeks. Elevated methylation levels of FOXP3-TSDR were significantly correlated of severity of atherosclerosis. We further found that FOXP3-TSDR methylation was inversely related to the percentages of Treg TGF-β (transforming growth factor-β) and IL (interleukin)-10 levels. Our results indicate that elevated methylation levels of FOXP3-TSDR are associated with increased risk for adverse outcomes in patients with ACS.

Epigallocatechin gallate ameliorates airway inflammation by regulating Treg/Th17 imbalance in an asthmatic mouse model

Epigallocatechin gallate (EGCG) is a polyphenol that is found in green tea that has been shown to ameliorate airway inflammation in an ovalbumin-sensitized asthmatic mouse model. The purpose of this study was to investigate whether the immunomodulatory and anti-inflammatory effects of EGCG by regulating the regulatory T cell (Treg)/Th 17 cells balance in this model. Female BALB/c mice were sensitized and challenged with ovalbumin by intraperitoneal injection. EGCG was administered to asthmatic mice intraperitoneally 1 h before each OVA challenge. Airway hyperresponsiveness (AHR) was measured, and lung inflammatory infiltrations were assessed by hematoxylin and eosin (HE) staining. Serum OVA-specific IgE levels, Interleukin-10 (IL-10) levels and Interleukin-17A (IL-17A) levels in the bronchoalveolar lavage fluid (BALF), serum, and splenocyte culture supernatants were measured by ELISA. Flow cytometry was used to assess the effects of EGCG on the frequency of CD4⁺CD25⁺Foxp3⁺Treg cells in the splenocytes and real-time PCR method was used to measure the expression of Forkhead box P3 (Foxp3) mRNA and retinoid-related orphan receptor gammat (RORγt) mRNA in the lung tissue. The results showed that administration of EGCG significantly decreased AHR and OVA specific IgE in the serum, increased IL-10 levels in the BALF, serum, and splenocyte culture supernatant, and the frequency of CD4⁺CD25⁺Foxp3⁺Treg cells in the splenocytes in asthmatic mice. Administration of EGCG also ameliorated airway inflammation and eosinophil infiltrations in asthmatic mice. These results suggested that EGCG likely ameliorated OVA-induced airway inflammation by increasing the production of IL-10, the number of CD4⁺CD25⁺Foxp3⁺Treg cells and expression of Foxp3 mRNA in the lung tissue, and it could be an effective agent for treating asthma.

Dietary Prevention of Colitis by Aronia Berry is Mediated Through Increased Th17 and Treg

SCOPE

Increased fruit consumption is associated with reduced risk of colitis. It has been investigated whether the anti-colitic effects of the polyphenol-rich aronia berry (Aronia mitschurinii 'Viking') are mediated through Th17 and Treg.

METHODS AND RESULTS

Colitis is induced in recombinase activating gene-1 deficient mice injected with syngeneic CD4⁺ CD62L⁺ naïve T cells. Mice consume either 4.5% w/w aronia-berry-supplemented or a control diet concurrent with T cell transfer. The extent of colitis and immunocyte populations are evaluated at weeks 3 to 7 after transfer. Aronia consumption prevents colitic wasting and reduces colon weight/length ratios relative to the control diet at weeks 5 and 7. Compared to the control diet, aronia feeding increases Treg in mesenteric lymph node at all colitis stages. Treg and regulatory Th17 subpopulations (IL-17A⁺ IL-10⁺ and IL-17A⁺ IL-22⁺ ) are increased in lamina propria and spleen at week 5 in aronia-fed mice. Aronia feeding also decreases total CD4⁺ cells but increases colonic Tregs. The ability of aronia to modulate colonic cytokines is associated with functional T cell IL-10 and increased diversity of microbiota.

CONCLUSIONS

Aronia berry consumption inhibits adoptive transfer colitis by increasing Treg and regulatory Th17 cells. Dietary modulation of T cells is dynamic and precedes colitic wasting.

The Immunomodulatory and Anti-Inflammatory Role of Polyphenols

This review offers a systematic understanding about how polyphenols target multiple inflammatory components and lead to anti-inflammatory mechanisms. It provides a clear understanding of the molecular mechanisms of action of phenolic compounds. Polyphenols regulate immunity by interfering with immune cell regulation, proinflammatory cytokines' synthesis, and gene expression. They inactivate NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) and modulate mitogen-activated protein Kinase (MAPk) and arachidonic acids pathways. Polyphenolic compounds inhibit phosphatidylinositide 3-kinases/protein kinase B (PI3K/AkT), inhibitor of kappa kinase/c-Jun amino-terminal kinases (IKK/JNK), mammalian target of rapamycin complex 1 (mTORC1) which is a protein complex that controls protein synthesis, and JAK/STAT. They can suppress toll-like receptor (TLR) and pro-inflammatory genes' expression. Their antioxidant activity and ability to inhibit enzymes involved in the production of eicosanoids contribute as well to their anti-inflammation properties. They inhibit certain enzymes involved in reactive oxygen species ROS production like xanthine oxidase and NADPH oxidase (NOX) while they upregulate other endogenous antioxidant enzymes like superoxide dismutase (SOD), catalase, and glutathione (GSH) peroxidase (Px). Furthermore, they inhibit phospholipase A2 (PLA2), cyclooxygenase (COX) and lipoxygenase (LOX) leading to a reduction in the production of prostaglandins (PGs) and leukotrienes (LTs) and inflammation antagonism. The effects of these biologically active compounds on the immune system are associated with extended health benefits for different chronic inflammatory diseases. Studies of plant extracts and compounds show that polyphenols can play a beneficial role in the prevention and the progress of chronic diseases related to inflammation such as diabetes, obesity, neurodegeneration, cancers, and cardiovascular diseases, among other conditions.

Prophylactic vs. Therapeutic Treatment With P2Et Polyphenol-Rich Extract Has Opposite Effects on Tumor Growth

Polyphenols have tumoricidal effects via anti-proliferative, anti-angiogenic and cytotoxic mechanisms and have recently been demonstrated to modulate the immune response through their anti- or pro- oxidant activity. Nevertheless, it remains controversial whether antioxidant-rich supplements have real beneficial effects on health, especially in complex diseases such as cancer. We previously identified a polyphenol-rich extract obtained from Caesalpinia spinosa (P2Et) with anti-tumor activity in both breast carcinoma and melanoma. The present work evaluated the ability of P2Et extract to modulate the immune system in either the steady state or following tumor challenge. We found that the prophylactic treatment of healthy mice increased the number of CD4⁺ and CD8⁺ activated T, NK, regulatory T, dendritic and myeloid-derived suppressor cells in lymphoid organs together with a significant increase in plasma IL-6. Interestingly, this pre-conditioning of the host immune system with P2Et did not involve a protective effect against the control of tumor growth and metastasis in transplantable models of melanoma (B16) and breast cancer (4T1), but in contrast, a detrimental effect was observed in both models. We further demonstrated that this effect was at least partly due to an increase in regulatory T cells, myeloid-derived suppressor cells, and proinflammatory cytokines, with a concomitant decrease in CD4⁺ and CD8⁺ T cells. Taken together, these results suggest that the anti-tumor and immunomodulation properties of the P2Et extract critically depend on the presence of the tumor and might be mediated by the complex interactions between the tumor cells and the other components of the tumor microenvironment.

Obesity treatment by epigallocatechin-3-gallate-regulated bile acid signaling and its enriched Akkermansia muciniphila

Dysregulated bile acid (BA) synthesis is accompanied by dysbiosis, leading to compromised metabolism. This study analyzes the effect of epigallocatechin-3-gallate (EGCG) on diet-induced obesity through regulation of BA signaling and gut microbiota. The data revealed that EGCG effectively reduced diet-increased obesity, visceral fat, and insulin resistance. Gene profiling data showed that EGCG had a significant impact on regulating genes implicated in fatty acid uptake, adipogenesis, and metabolism in the adipose tissue. In addition, metabolomics analysis revealed that EGCG altered the lipid and sugar metabolic pathways. In the intestine, EGCG reduced the FXR agonist chenodeoxycholic acid, as well as the FXR-regulated pathway, suggesting intestinal FXR deactivation. However, in the liver, EGCG increased the concentration of FXR and TGR-5 agonists and their regulated signaling. Furthermore, our data suggested that EGCG activated Takeda G protein receptor (TGR)-5 based on increased GLP-1 release and elevated serum PYY level. EGCG and antibiotics had distinct antibacterial effects. They also differentially altered body weight and BA composition. EGCG, but not antibiotics, increased Verrucomicrobiaceae, under which EGCG promoted intestinal bloom of Akkermansia muciniphila. Excitingly, A. muciniphila was as effective as EGCG in treating diet-induced obesity. Together, EGCG shifts gut microbiota and regulates BA signaling thereby having a metabolic beneficial effect.-Sheng, L., Jena, P. K., Liu, H.-X., Hu, Y., Nagar, N., Bronner, D. N., Settles, M. L., Bäumler, A. J. Wan, Y.-J. Y. Obesity treatment by epigallocatechin-3-gallate-regulated bile acid signaling and its enriched Akkermansia muciniphila.

Cha-Koji, comprising green tea leaves fermented with Aspergillus luchuensis var kawachii kitahara, increases regulatory T cell production in mice and humans

Green tea leaves fermented with Aspergillus luchuensis var kawachii kitahara (Cha-Koji) are a health food containing live A. luchuensis. In this study, we examined the effects of Cha-Koji on the immune system and the enteric environment. First, we designed a clinical trial; after ingesting Cha-Koji daily for 28 days, blood parameters and the fecal composition of the participants were analyzed. Similarly, mice were administered (oral administration) with Cha-Koji suspension or its vehicle for 14 days. Thereafter, both humans and mice were examined by analyzing their immune cell phenotypes and intestinal microbiota. Regulatory T cell (Treg) numbers were significantly increased after administering Cha-Koji. An increase of Clostridium subcluster XIVa, that were known to be rich in butyrate-producing bacterium, was observed in human feces, but not in mice. These results suggest that Cha-Koji has the ability to increase Treg production in both humans and mice, irrespective of the presence of enteric butyrate.

Immunomodulation by food: impact on gut immunity and immune cell function

Recent studies have revealed that various food components affect the immune response. These components act on various immune cells, and their effects are mediated through the intestinal immune system and, in some cases, the intestinal microbiota. In this review, we describe the immunomodulating effects of various food components, including probiotics, prebiotics, polysaccharides, vitamins, minerals, fatty acids, peptides, amino acids and polyphenols. Some of these components enhance immune responses, leading to host defense against infection, whereas others inhibit immune responses, thus suppressing allergy and inflammation.

Prostaglandin E2 restrains human Treg cell differentiation via E prostanoid receptor 2-protein kinase A signaling

Regulatory T cells (Treg cells) belong to a class of immunosuppressive cells that control the pathological changes of autoimmunity and inflammation. Prostaglandin E₂ (PGE₂) is a potent lipid mediator of immune inflammation including rheumatoid arthritis (RA) that exerts its effects via four subtypes of G-protein-coupled receptors (EP1-4). The ability of PGE₂ to regulate human Treg differentiation has not yet been reported. In the current study, we investigated the effects of PGE₂ on the differentiation of naïve T cells from healthy and RA patients into Treg cells and the intracellular signaling involved in this process in vitro. Our data indicate that PGE₂ negatively influenced the percentage of Treg cells and Foxp3 mRNA expression. The regulatory effects of PGE₂ were associated with increased intracellular cAMP levels and PKA activity. EP2 receptors may mediate the inhibitory role of PGE₂, since PGE₂ actions were mimicked by EP2 agonist (Butaprost) and cAMP agonist (Sp-8-CPT-cAMPS) but were reversed by an EP2 antagonist (PF-04418948) and a PKA inhibitor (H-89). PGE₂ negatively modulated the expression of cytotoxic T lymphocyte antigen-4 (CTLA-4) and glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR), as well as the production of interleukin (IL)-10 by Treg cells via EP2 receptors and cAMP/PKA signaling. All these findings indicate that PGE₂ can inhibit Treg differentiation mediated through the EP2-cAMP/PKA signaling pathway, and suggest novel immune-based therapies for use in RA treatment.