l-Arginine-Dependent Epigenetic Regulation of Interleukin-10, but Not Transforming Growth Factor-β, Production by Neonatal Regulatory T Lymphocytes

Oyster powder supplementation enhances immune function in mice partly through modulating the gut microbiota and arginine metabolism

Oysters are well-known for their health benefits such as immuno-modulatory functions. The intestinal microbiome serves as a key mediator between diet and immune regulation. This study aimed to investigate whether oyster consumption could alleviate cyclophosphamide (Cy)-induced immunosuppression by promoting intestinal homeostasis. In mice treated with Cy, a significant decrease in immune cells and cytokines was observed. In contrast, mice supplemented with oyster powder demonstrated elevated numbers of immune cells in the spleen and small intestine, as well as enhanced serum production of IL-1β, IL-2, TNF-α, and IFN-γ. Furthermore, oyster consumption improved the composition of the gut microbiota by promoting beneficial bacteria and inhibiting harmful ones. Metabolomics analysis revealed that oyster powder treatment significantly enhanced the arginine biosynthesis pathway, and further analysis found that the consumption of oysters led to increased arginine levels. Correlation analysis showed a significant positive correlation between L-arginine and immune-related markers. Collectively, these findings suggest that oyster consumption may enhance immunity by modulating the gut microbiota and boosting arginine biosynthesis pathways. Dietary oyster consumption could be an effective strategy to support immune health.

Proof of Concept: Effects of an Immune-Enhancing Formula on Clinical Markers of Critical Coronavirus Disease 2019 Cases

Background/Objectives: The rapid viral spread observed in coronavirus disease 2019 (COVID-19) is capable of inducing the secretion of excessive inflammatory cytokines. The resulting multi-organ damage is a severe complication that can be attenuated through adequate nutrition. Formulae enhanced with either glutamine or arginine are conditionally essential amino acids that have been proven to improve the condition of hospitalized patients. This retrospective study aimed to investigate the effects of administering an immune-enhancing enteral formula enhanced with arginine and glutamine on the clinical signs and biomarkers of patients with severe COVID-19. Methods: After checking the data of 232 patients enrolled in the biobank for completeness and eligibility, 31 patients with severe COVID-19 in the intensive care unit at Taipei Tzu Chi Hospital were grouped based on the type of enteral formula used: 16 patients received the control formula, and 15 patients received the immune-enhancing formula. Baseline characteristics, clinical signs, and inflammatory markers were analyzed for differences. Results: An increase in IL-10 levels in the intervention group was observed (p = 0.048). Changes in other inflammatory cytokine levels were insignificant. Conclusions: Providing an enteral formula enriched with glutamine and arginine to severe COVID-19 patients may help improve their anti-inflammatory marker levels. Further interventional study utilizing enteral formula enriched with glutamine and arginine is needed to confirm the findings of this study.

Decoding the potential role of regulatory T cells in sepsis-induced immunosuppression

Sepsis, a multiorgan dysfunction with high incidence and mortality, is caused by an imbalanced host-to-infection immune response. Organ-support therapy improves the early survival rate of sepsis patients. In the long term, those who survive the "cytokine storm" and its secondary damage usually show higher susceptibility to secondary infections and sepsis-induced immunosuppression, in which regulatory T cells (Tregs) are evidenced to play an essential role. However, the potential role and mechanism of Tregs in sepsis-induced immunosuppression remains elusive. In this review, we elucidate the role of different functional subpopulations of Tregs during sepsis and then review the mechanism of sepsis-induced immunosuppression from the aspects of regulatory characteristics, epigenetic modification, and immunometabolism of Tregs. Thoroughly understanding how Tregs impact the immune system during sepsis may shed light on preclinical research and help improve the translational value of sepsis immunotherapy.

The effect of 24-hour sleep deprivation and anaerobic exercise on the expression of BAX, BCL2, BMAL1 and CCAR2 genes in peripheral blood mononuclear cells after L-arginine supplementation

Sleep deprivation disrupt the circadian clock and exercise performance. Defective oxidative stress caused by sleep deprivation may affect the expression of genes involved in cell apoptosis. Since a number of studies have shown the anti-apoptotic effect of L-arginine, so the aim of this study was to evaluate the effect of eight weeks of L-arginine supplementation on the expression of brain and muscle ARNT-like protein 1 (BMAL1), cell cycle and apoptosis regulator 2 (CCAR2), and BAX and BCL2 genes during sleep deprivation and acute anaerobic exercise. Participants included 20 healthy men age 26-35 years, randomized into the L-arginine intervention group (n = 10) and a placebo control (n = 10). The running-based anaerobic sprint test (RAST) was used for anaerobic exercise. Intervention subjects took one 1000 mg L-arginine tablet daily for 8 weeks. The Real-Time PCR method was used to determine apoptosis gene expression in peripheral blood mononuclear cells (PBMCs). Acute anaerobic exercise and sleep deprivation both increased the expression of BAX and CCAR2 genes, and decreased the expression of BCL2 and BMAL1 genes (p < 0.05 for all). L-arginine supplementation increased the expression of BMAL1 and BCL2 genes and decreased the expression of BAX and CCAR2 genes relative to control (p < 0.05). L-Arginine controlled the increase in expression of BAX and CCAR2 genes and the decrease in expression of BCL2 and BMAL1 genes in response to sleep deprivation and acute anaerobic exercise (p < 0.05). Our results showed that 24-hour sleep deprivation and acute anaerobic exercise increased the expression of pro-apoptotic genes (BAX and CCAR2) and decreased the expression of anti-apoptotic genes (BCL2 and BMAL1), although the effect of sleep deprivation is greater. In this situation, L-arginine supplementation may balance the apoptotic state of peripheral blood mononuclear cells. However, any recommendation about this needs further research.

Aqueous Fraction from Cucumis sativus Aerial Parts Attenuates Angiotensin II-Induced Endothelial Dysfunction In Vivo by Activating Akt

BACKGROUND

Endothelial dysfunction (ED) is a marker of vascular damage and a precursor of cardiovascular diseases such as hypertension, which involve inflammation and organ damage. Nitric oxide (NO), produced by eNOS, which is induced by pAKT, plays a crucial role in the function of a healthy endothelium.

METHODS

A combination of subfractions SF1 and SF3 (C4) of the aqueous fraction from Cucumis sativus (Cs-Aq) was evaluated to control endothelial dysfunction in vivo and on HMEC-1 cells to assess the involvement of pAkt in vitro. C57BL/6J mice were injected daily with angiotensin II (Ang-II) for 10 weeks. Once hypertension was established, either Cs-AqC4 or losartan was orally administered along with Ang-II for a further 10 weeks. Blood pressure (BP) was measured at weeks 0, 5, 10, 15, and 20. In addition, serum creatinine, inflammatory status (in the kidney), tissue damage, and vascular remodeling (in the liver and aorta) were evaluated. Cs-AqC4 was also tested in vitro on HMEC-1 cells stimulated by Ang-II to assess the involvement of Akt phosphorylation.

RESULTS

Cs-AqC4 decreased systolic and diastolic BP, reversed vascular remodeling, decreased IL-1β and TGF-β, increased IL-10, and decreased kidney and liver damage. In HMEC-1 cells, AKT phosphorylation and NO production were increased.

CONCLUSIONS

Cs-AqC4 controlled inflammation and vascular remodeling, alleviating hypertension; it also improved tissue damage associated with ED, probably via Akt activation.

An evidence-based debate on epigenetics and immunosenescence in COVID-19

Immunosenescence contributes to the decline of immune function leading to a reduced ability to respond to severe coronavirus disease 2019 (COVID-19) in elderly patients. Clinical course of COVID-19 is widely heterogeneous and guided by the possible interplay between genetic background and epigenetic-sensitive mechanisms underlying the immunosenescence which could explain, at least in part, the higher percentage of disease severity in elderly individuals. The most convincing evidence regards the hypomethylation of the angiotensin-converting enzyme 2 (ACE2) promoter gene in lungs as well as the citrullination of histone H3 in neutrophils which have been associated with worsening of COVID-19 outcome in elderly patients. In contrast, centenarians who have showed milder symptoms have been associated to a younger "epigenetic age" based on DNA methylation profiles at specific genomic sites (epigenetic clock). Some large prospective studies showed that the acceleration of epigenetic aging as well as the shortening of telomeres were significantly associated with lymphopenia and poor outcome suggesting prognostic biomarkers in elderly COVID-19 patients. Furthermore, randomized clinical trials showed that statins, L-arginine, and resveratrol could mediate anti-inflammatory effects via indirect epigenetic interference and might improve COVID-19 outcome. Here, we discuss the epigenetic-sensitive events which might contribute to increase the risk of severity and mortality in older subjects and possible targeted therapies to counteract immunosenescence.

The methylation profile of IL4, IL5, IL10, IFNG and FOXP3 associated with environmental exposures differed between Polish infants with the food allergy and/or atopic dermatitis and without the disease

Objectives

Epigenetic dynamics has been indicated to play a role in allergy development. The environmental stimuli have been shown to influence the methylation processes. This study investigated the differences in CpGs methylation rate of immune-attached genes between healthy and allergic infants. The research was aimed at finding evidence for the impact of environmental factors on methylation-based regulation of immunological processes in early childhood.

Methods

The analysis of methylation level of CpGs in the IL4, IL5, IL10, IFNG and FOXP3 genes was performed using high resolution melt real time PCR technology. DNA was isolated from whole blood of Polish healthy and allergic infants, with food allergy and/or atopic dermatitis, aged under six months.

Results

The significantly lower methylation level of FOXP3 among allergic infants compared to healthy ones was reported. Additional differences in methylation rates were found, when combining with environmental factors. In different studied groups, negative correlations between age and the IL10 and FOXP3 methylation were detected, and positive - in the case of IL4. Among infants with different allergy symptoms, the decrease in methylation level of IFNG, IL10, IL4 and FOXP3 associated with passive smoke exposure was observed. Complications during pregnancy were linked to different pattern of the IFNG, IL5, IL4 and IL10 methylation depending on allergy status. The IFNG and IL5 methylation rates were higher among exclusively breastfed infants with atopic dermatitis compared to the non-breastfed. A decrease in the IFNG methylation was noted among allergic patients fed exclusively with milk formula. In different study groups, a negative correlation between IFNG, IL5 methylation and maternal BMI or IL5 methylation and weight was noted. Some positive correlations between methylation rate of IL10 and child's weight were found. A higher methylation of IL4 was positively correlated with the number of family members with allergy.

Conclusion

The FOXP3 methylation in allergic infants was lower than in the healthy ones. The methylation profile of IL4, IL5, IL10, IFNG and FOXP3 associated with environmental exposures differed between the studied groups. The results offer insights into epigenetic regulation of immunological response in early childhood.

The role of metabolism on regulatory T cell development and its impact in tumor and transplantation immunity

Regulatory CD4⁺ T (Treg) cells play a key role in the induction of immune tolerance and in the prevention of autoimmune diseases. Treg cells are defined by the expression of transcription factor FOXP3, which ensures proliferation and induction of the suppressor activity of this cell population. In a tumor microenvironment, after transplantation or during autoimmune diseases, Treg cells can respond to various signals from their environment and this property ensures their suppressor function. Recent studies showed that a metabolic signaling pathway of Treg cells are essential in the control of Treg cell proliferation processes. This review presents the latest research highlights on how the influence of extracellular factors (e.g. nutrients, vitamins and metabolites) as well as intracellular metabolic signaling pathways regulate tissue specificity of Treg cells and heterogeneity of this cell population. Understanding the metabolic regulation of Treg cells should provide new insights into immune homeostasis and disorders along with important therapeutic implications for autoimmune diseases, cancer and other immune-system-mediated disorders.

Unravelling the Complex Relationship between Diet and Nephrolithiasis: The Role of Nutrigenomics and Nutrigenetics

Nephrolithiasis is an increasingly prevalent condition, especially in high income countries, and is associated with high morbidity. Extraordinary progress in genetics made the identification of genetic forms of nephrolithiasis possible. These genetic diseases are usually rare and do not account for the most common forms of nephrolithiasis that are the result of several factors such as environment, dietary habits, and predisposing genes. This knowledge has shaped what we classify as nephrolithiasis, a condition that is now recognized as systemic. How and to what extent all these factors interact with one another and end in kidney stone formation, growth, and recurrence is not completely understood. Two new research fields have recently been trying to give some answers: nutrigenomics and nutrigenetics. These fields have the aim of understanding the intricate diet/genome interface that influences gene expression regulation mainly through epigenetic mechanisms and results in specific medical conditions such as cancer, metabolic syndrome, and cardiovascular diseases. Epigenetics seems to play a crucial role and could represent the link between environmental factors, that we are constantly exposed to, and risk factors for nephrolithiasis. In this systematic review, we summarize all the available evidence of proven or hypothesized epigenetic mechanisms related to nephrolithiasis.

Metabolic profiles of regulatory T cells and their adaptations to the tumor microenvironment: implications for antitumor immunity

Characterized by the expression of the critical transcription factor forkhead box protein P3, regulatory T (Treg) cells are an essential part of the immune system, with a dual effect on the pathogenesis of autoimmune diseases and cancer. Targeting Tregs to reestablish the proinflammatory and immunogenic tumor microenvironment (TME) is an increasingly attractive strategy for cancer treatment and has been emphasized in recent years. However, attempts have been significantly hindered by the subsequent autoimmunity after Treg ablation owing to systemic loss of their suppressive capacity. Cellular metabolic reprogramming is acknowledged as a hallmark of cancer, and emerging evidence suggests that elucidating the underlying mechanisms of how intratumoral Tregs acquire metabolic fitness and superior immunosuppression in the TME may contribute to clinical benefits. In this review, we discuss the common and distinct metabolic profiles of Tregs in peripheral tissues and the TME, as well as the differences between Tregs and other conventional T cells in their metabolic preferences. By focusing on the critical roles of different metabolic programs, such as glycolysis, oxidative phosphorylation, fatty acid oxidation, fatty acid synthesis, and amino acid metabolism, as well as their essential regulators in modulating Treg proliferation, migration, and function, we hope to provide new insights into Treg cell-targeted antitumor immunotherapies.

The Role of Autophagy in the Function of CD4+ T Cells and the Development of Chronic Inflammatory Diseases

Uncontrolled acute inflammation progresses to persistent inflammation that leads to various chronic inflammatory diseases, including asthma, Crohn’s disease, rheumatoid arthritis, multiple sclerosis, and systemic lupus erythematosus. CD4⁺ T cells are key immune cells that determine the development of these chronic inflammatory diseases. CD4⁺ T cells orchestrate adaptive immune responses by producing cytokines and effector molecules. These functional roles of T cells vary depending on the surrounding inflammatory or anatomical environment. Autophagy is an important process that can regulate the function of CD4⁺ T cells. By lysosomal degradation of cytoplasmic materials, autophagy mediates CD4⁺ T cell-mediated immune responses, including cytokine production, proliferation, and differentiation. Furthermore, through canonical processes involving autophagy machinery, autophagy also contributes to the development of chronic inflammatory diseases. Therefore, a targeted intervention of autophagy processes could be used to treat chronic inflammatory diseases. This review focuses on the role of autophagy via CD4⁺ T cells in the pathogenesis and treatment of such diseases. In particular, we explore the underlying mechanisms of autophagy in the regulation of CD4⁺ T cell metabolism, survival, development, proliferation, differentiation, and aging. Furthermore, we suggest that autophagy-mediated modulation of CD4⁺ T cells is a promising therapeutic target for treating chronic inflammatory diseases.

The Functional DNA Methylation Signatures Relevant to Altered Immune Response of Neonatal T Cells with l-Arginine Supplementation

l-Arginine is an important nutrient in the infant diet that significantly regulates the maturation of the immune system in neonates, including the maturation of CD4⁺ T cells. The biological activities of CD4⁺ T cells differ substantially between neonates and adults, and these differences may be governed by epigenetic processes. Investigating these differences and the causative processes may help understand neonatal and developmental immunity. In this study, we compared the functional DNA methylation profiles in CD4⁺ T cells of neonates and adults, focusing on the role of l-arginine supplementation. Umbilical cord blood and adult CD4⁺ T cells were cultured with/without l-arginine treatment. By comparing DNA methylation in samples without l-arginine treatment, we found that CD4⁺ T cells of neonatal cord blood generally showed higher DNA methylation than those of adults (average CpG methylation percentage 0.6305 for neonate and 0.6254 for adult, t-test p-value < 0.0001), suggesting gene silencing in neonates. By examining DNA methylation patterns of CpG dinucleotides induced by l-arginine treatment, we found that more CpG dinucleotides were hypomethylated and more genes appeared to be activated in neonatal T-cells as compared with adult. Genes activated by l-arginine stimulation of cord blood samples were more enriched regarding immune-related pathways. CpG dinucleotides at IL-13 promoter regions were hypomethylated after l-arginine stimulation. Hypomethylated CpG dinucleotides corresponded to higher IL-13 gene expression and cytokine production. Thus, DNA methylation partially accounts for the mechanism underlying differential immune function in neonates. Modulatory effects of l-arginine on DNA methylation are gene-specific. Nutritional intervention is a potential strategy to modulate immune function of neonates.

Inhibition of arginase modulates T-cell response in the tumor microenvironment of lung carcinoma

Immunotherapy has demonstrated significant activity in a broad range of cancer types, but still the majority of patients receiving it do not maintain durable therapeutic responses. Amino acid metabolism has been proposed to be involved in the regulation of immune response. Here, we investigated in detail the role of arginase 1 (Arg1) in the modulation of antitumor immune response against poorly immunogenic Lewis lung carcinoma. We observed that tumor progression is associated with an incremental increase in the number of Arg1⁺ myeloid cells that accumulate in the tumor microenvironment and cause systemic depletion of ʟ-arginine. In advanced tumors, the systemic concentrations of ʟ-arginine are decreased to levels that impair the proliferation of antigen-specific T-cells. Systemic or myeloid-specific Arg1 deletion improves antigen-induced proliferation of adoptively transferred T-cells and leads to inhibition of tumor growth. Arginase inhibitor was demonstrated to modestly inhibit tumor growth when used alone, and to potentiate antitumor effects of anti-PD-1 monoclonal antibodies and STING agonist. The effectiveness of the combination immunotherapy was insufficient to induce complete antitumor responses, but was significantly better than treatment with the checkpoint inhibitor alone. Together, these results indicate that arginase inhibition alone is of modest therapeutic benefit in poorly immunogenic tumors; however, in combination with other treatment strategies it may significantly improve survival outcomes.

Immunonutrition effects on coping with COVID-19

COVID-19 implications are still a threat to global health. In the face of this pandemic, food and nutrition are key issues that can boost the immune system. The bioactivity of functional foods and nutrients (probiotics, prebiotics, water- and fat-soluble vitamins, minerals, flavonoids, glutamine, arginine, nucleotides, and PUFAs) contributes to immune system modulation, which establishes the status of nutrients as a factor of immune competence. These foods can contribute, especially during a pandemic, to the minimization of complications of SARS-CoV-2 infection. Therefore, it is important to support the nutritional strategies for strengthening the immune status, associated with good eating habits, as a way to confront COVID-19.

Prenatal Exposure to Di-Ethyl Phthalate (DEP) Is Related to Increasing Neonatal IgE Levels and the Altering of the Immune Polarization of Helper-T Cells

Introduction: Phthalates are substances that are added to plastic products to increase their plasticity. These substances are released easily into the environment and can act as endocrine disruptors. Epidemiological studies in children have showed inconsistent findings regarding the relationship between prenatal or postnatal exposure to phthalates and the risk of allergic disease. Our hypothesis is that prenatal exposure to phthalates may contribute to the development of allergies in children. Material and methods: The objective of this study was to determine the associations between urinary phthalate metabolite concentrations in pregnant women, maternal atopic diathesis, maternal lifestyle, and cord blood IgE. Pregnant mothers and paired newborns (n = 101) were enrolled from an antenatal clinic. The epidemiologic data and the clinical information were collected using standard questionnaires and medical records. The maternal blood and urine samples were collected at 24–28 weeks gestation, and cord blood IgE, IL-12p70, IL-4, and IL-10 levels were determined from the newborns at birth. The link between phthalates and maternal IgE was also assessed. To investigate the effects of phthalates on neonatal immunity, cord blood mononuclear cells (MNCs) were used for cytokine induction in another in vitro experiment. Results: We found that maternal urine monoethyl phthalate (MEP) (a metabolite of di-ethyl phthalate (DEP)) concentrations are positively correlated with the cord blood IgE of the corresponding newborns. The cord blood IL-12p70 levels of mothers with higher maternal urine MEP groups (high DEP exposure) were lower than mothers with low DEP exposure. In vitro experiments demonstrated that DEP could enhance IL-4 production of cord blood MNCs rather than adult MNCs. Conclusion: Prenatal DEP exposure is related to neonatal IgE level and alternation of cytokines relevant to Th1/Th2 polarization. This suggests the existence of a link between prenatal exposure to specific plasticizers and the future development of allergies.

Regulatory T cell metabolism at the intersection between autoimmune diseases and cancer

Regulatory T cells (Tregs) are critical for peripheral immune tolerance and homeostasis, and altered Treg behavior is involved in many pathologies, including autoimmunity and cancer. The expression of the transcription factor FoxP3 in Tregs is fundamental to maintaining their stability and immunosuppressive function. Recent studies have highlighted the crucial role that metabolic reprogramming plays in controlling Treg plasticity, stability, and function. In this review, we summarize how the availability and use of various nutrients and metabolites influence Treg metabolic pathways and activity. We also discuss how Treg-intrinsic metabolic programs define and shape their differentiation, FoxP3 expression, and suppressive capacity. Lastly, we explore how manipulating the regulation of Treg metabolism might be exploited in different disease settings to achieve novel immunotherapies.

Interleukin 10: the critical role of a pleiotropic cytokine in food allergy

Despite advances in research, the pathophysiology of food allergy has not yet been fully elucidated. IL-10 has both a pro- and anti-inflammatory effect on the development of food allergy and in order to understand its different immune-modulatory effects the factors that influence the inflammatory microenvironment need to be taken into account. Specific single nucleotide polymorphisms of the IL-10 gene seem to confer an increased risk of developing food allergy, but to date there is a substantial lack of genome- wide association studies regarding the genetic and epigenetic underpinnings of the disease. Special interest has been drawn to the development of allergen-specific regulatory CD4+CD25+ T-cells secreting IL-10 in the immunotherapy of allergic diseases. In addition, a distinct population of human tolerogenic dendritic cells (DC), DC-10 seems to hold great potential and could potentially serve as a therapeutic tool to improve the management of food allergy.

Epigenetic Changes Associated With Interleukin-10

IL-10 is a regulator of inflammation and immunosuppression. IL-10 regulates a variety of immune cells to limit and stop the inflammatory response, and thus plays an important role in autoimmune diseases, inflammatory diseases and cancer. IL-10 is closely related to epigenetic modification, in which changes in DNA methylation of IL-10 gene can affect mRNA and protein levels of IL-10. In addition, changes in histone modifications, especially histone acetylation, can also lead to abnormal expression of IL-10 mRNA. At the same time, a handful of IL-10 related microRNAs (miRNAs) are found to be aberrantly expressed in multiple diseases. Besides, long non-coding RNA (lncRNA) growth arrest specific transcript 5 (GAS5) also inhibits IL-10 expression. Here, we reviewed the epigenetic changes related to IL-10 in various diseases, as well as the regulation of IL-10 gene expression in various diseases by epigenetic modifications such as DNA methylation, histone modification, miRNA, and lncRNA.

Myeloid Cell-Derived Arginase in Cancer Immune Response

Amino acid metabolism is a critical regulator of the immune response, and its modulating becomes a promising approach in various forms of immunotherapy. Insufficient concentrations of essential amino acids restrict T-cells activation and proliferation. However, only arginases, that degrade L-arginine, as well as enzymes that hydrolyze L-tryptophan are substantially increased in cancer. Two arginase isoforms, ARG1 and ARG2, have been found to be present in tumors and their increased activity usually correlates with more advanced disease and worse clinical prognosis. Nearly all types of myeloid cells were reported to produce arginases and the increased numbers of various populations of myeloid-derived suppressor cells and macrophages correlate with inferior clinical outcomes of cancer patients. Here, we describe the role of arginases produced by myeloid cells in regulating various populations of immune cells, discuss molecular mechanisms of immunoregulatory processes involving L-arginine metabolism and outline therapeutic approaches to mitigate the negative effects of arginases on antitumor immune response. Development of potent arginase inhibitors, with improved pharmacokinetic properties, may lead to the elaboration of novel therapeutic strategies based on targeting immunoregulatory pathways controlled by L-arginine degradation.

Metabolic adaptation orchestrates tissue context-dependent behavior in regulatory T cells

The diverse distribution and functions of regulatory T cells (Tregs) ensure tissue and immune homeostasis; however, it remains unclear which factors can guide distribution, local differentiation, and tissue context-specific behavior in Tregs. Although the emerging concept that Tregs could re-adjust their transcriptome based on their habitations is supported by recent findings, the underlying mechanisms that reprogram transcriptome in Tregs are unknown. In the past decade, metabolic machineries have been revealed as a new regulatory circuit, known as immunometabolic regulation, to orchestrate activation, differentiation, and functions in a variety of immune cells, including Tregs. Given that systemic and local alterations of nutrient availability and metabolite profile associate with perturbation of Treg abundance and functions, it highlights that immunometabolic regulation may be one of the mechanisms that orchestrate tissue context-specific regulation in Tregs. The understanding on how metabolic program instructs Tregs in peripheral tissues not only represents a critical opportunity to delineate a new avenue in Treg biology but also provides a unique window to harness Treg-targeting approaches for treating cancer and autoimmunity with minimizing side effects. This review will highlight the metabolic features on guiding Treg formation and function in a disease-oriented perspective and aim to pave the foundation for future studies.

Resveratrol Treatment Ameliorates Leptin Resistance and Adiposity Programed by the Combined Effect of Maternal and Post-Weaning High-Fat Diet

SCOPE

Prenatal high-fat (HF) and postnatal HF diet are both associated with obesity and metabolic disturbances in adults. Leptin resistance induced by obesity limits its biological effects. The anti-obesity mechanism of resveratrol in visceral adiposity is investigated here.

METHODS AND RESULTS

During mating and lactation, Sprague-Dawley dams are fed either control or a HF diet. Subsequently, the offspring are fed chow or an HF diet. A fifth group that received maternal/postnatal HF diet and resveratrol after weaning (HHR) is used to study the effects of resveratrol treatment. Resveratrol treatment alleviates adiposity programed by maternal and postnatal HF diet by decreasing feed intake or inducing metabolic changes. Resveratrol treatment is also found to ameliorate the decrease in SIRT1 abundance observed in retroperitoneal adipose tissue, programed by maternal and postnatal HF diet. Moreover, resveratrol therapy decreases plasma leptin level and increases leptin receptor expression in retroperitoneal adipose tissue through DNA methylation modification.

CONCLUSION

These results suggest that resveratrol can alleviate peripheral leptin resistance programed by the combined effect of prenatal and postnatal HF diet through epigenetic regulation of genes coding leptin and its receptor. It provides insights into a novel mechanism explaining the beneficial effects of resveratrol in obesity management.

Primed mesenchymal stem cells package exosomes with metabolites associated with immunomodulation

Mesenchymal stem cell (MSC) based therapies are currently being evaluated as a putative therapeutic in numerous human clinical trials. Recent reports have established that exosomes mediate much of the therapeutic properties of MSCs. Exosomes are nanovesicles which mediate intercellular communication, transmitting signals between cells which regulate a diverse range of biological processes. MSC-derived exosomes are packaged with numerous types of proteins and RNAs, however, their metabolomic and lipidomic profiles to date have not been well characterized. We previously reported that MSCs, in response to priming culture conditions that mimic the in vivo microenvironmental niche, substantially modulate cellular signaling and significantly increase the secretion of exosomes. Here we report that MSCs exposed to such priming conditions undergo glycolytic reprogramming, which homogenizes MSCs' metabolomic profile. In addition, we establish that exosomes derive from primed MSCs are packaged with numerous metabolites that have been directly associated with immunomodulation, including M2 macrophage polarization and regulatory T lymphocyte induction.

Targeting cytokines secreted by CD4+ CD25high CD127low regulatory T cells inhibits ovarian cancer progression

Epithelial ovarian cancer (EOC) is one of the major malignant cancers with high rates of early metastasis in which regulatory T cells (Tregs) play an important role. Tregs suppress immune responses and promote the development of tumours in patients with EOC. However, the underlying mechanisms remain unclear. In this study, we found higher levels of CD4⁺ CD25^high CD127^low Tregs in patients with EOC than in patients with benign ovarian tumours and healthy donors. The immune inhibitory effect of Tregs functions by maintaining high levels of immunosuppressive cytokines in EOC. The high levels of Tregs and related cytokines (TGF-β1 or IL-10) were associated with lymphatic metastasis and FIGO stages of patients with EOC. Expression of matrix metalloproteinase (MMP)-2 and tissue inhibitors of metalloproteinase (TIMP)-2 in EOC cell lines were significantly regulated in the coculture experiment with CD4⁺ CD25^high CD127^low Tregs sorted from EOC patients. Levels of MMP-2 and TIMP-2 conversely changed after blocking IL-10R and TGF-β1R in EOC cells. The invasion ability of EOC cells was also significantly downregulated in this process. The metastasis of EOC cells was correlated with the levels of TGF-β1 or IL-10. These findings suggested that immunosuppressive cytokines secreted by CD4⁺ Tregs could be a novel target for inhibiting EOC progression.

L-Arginine and L-Citrulline Supplementation Have Different Programming Effect on Regulatory T-Cells Function of Infantile Rats

Arginine is a semiessential amino acid in healthy adult human, but is essential for preterm, newborn or critically ill patients. Arginine can be supplied from our diet or de novo synthesis from citrulline. In conditions of sepsis or endotoxemia, arginine may be deficient and be accompanied with altered immune response. L-arginine supplementation can ameliorate dysregulated immune condition and improve prognosis. Many studies had tried L-arginine or L-citrulline supplementation to examine the effect on immune response in the adult population. Few had studied on the young children. In this study, we determined the effect of L-arginine and L-citrulline supplementation on the immune response of infantile rats. Male infantile rats received normal saline, L-arginine (200 mg/kg/day) or L-citrulline (200 mg/kg/day) intraperitoneally over postnatal day 8 to day 14. The infantile rats were then sacrificed. The blood was analyzed while the spleen was indicated for immune analysis after stimulation with concanavalin A (Con A) or lipopolysaccharide (LPS). We found L-arginine supplementation enhanced Th1 immune response by increasing IFN-γ production. Both the L-arginine and L-citrulline therapy can modulate regulatory T-cell (Treg) immune effects by increasing the IL-10 level. Only the L-citrulline group showed a TGF-β1 increase. Both L-arginine and L-citrulline therapy were also noted to decrease SMAD7 expression and enhance SIRT-1 abundance. However, FOXP3 expression was only modulated by L-citrulline treatment. We then concluded that L-arginine and L-citrulline supplementation can modulate the regulatory T-cells function differently for infantile rats.