Immunometabolic Effects Research Articles

Immunometabolic effects of lactate on humoral immunity in healthy individuals of different ages

Aging is characterized by chronic systemic inflammation and metabolic changes. We compare the metabolic status of B cells from young and elderly donors and found that aging is associated with higher oxygen consumption rates, and especially higher extracellular acidification rates, measures of oxidative phosphorylation and of anaerobic glycolysis, respectively. Importantly, this higher metabolic status, which reflects age-associated expansion of pro-inflammatory B cells, is found associated with higher secretion of lactate and autoimmune antibodies after in vitro stimulation. B cells from elderly individuals induce in vitro polarization of CD4+ T cells from young individuals into pro-inflammatory CD4+ T cells through metabolic pathways mediated by lactate, which can be inhibited by targeting lactate enzymes and transporters, as well as signaling pathways supporting anaerobic glycolysis. Lactate also induces immunosenescent B cells that are glycolytic, express transcripts for multiple pro-inflammatory molecules, and are characterized by a higher metabolic status. These results altogether may have relevant clinical implications and suggest alternative targets for therapeutic interventions in the elderly and patients with inflammatory conditions and diseases.

Protected biofactors and antioxidants reduce the negative consequences of virus and cold challenge by modulating immunometabolism via changes in the interleukin-6 receptor signaling cascade in the liver

Protected biofactors and antioxidants (PBA), and protected biofactors and antioxidants with protected organic acids and essential oils (PBA+POAEO) have been shown to have benefits in stressed or challenged birds. Here, we describe the immunometabolic changes observed in the liver of Ross 308 broilers during feed supplementation and brief physiological stress. These studied additives contain protected essential oils, organic acids, and vitamins which may have protective effects on the liver. Thus, we aimed to determine the signaling changes induced by these supplements and the resultant immunometabolic effects in the liver. All birds received a 2X dose of live bronchitis vaccine at d 0 and a 48-h cold challenge by reducing the temperature from 30 to 32°C, to 20 to 23°C on d 3 to 5. Control birds were fed a standard diet without supplementation. Liver samples were collected to evaluate the effects of these treatments on cytokine gene expression and protein phosphorylation via kinome peptide array. ANOVA was used for statistical analysis of the gene expression data (significance at a p-value of 0.05), and PIIKA2 was used for statistical evaluation and comparative analysis of the kinome peptide array data. At d 15, the kinome peptide array analysis and gene expression data showed stimulation of the interleukin 6 receptor (IL-6R) signal transduction for host protection via heightened immune response while inducing immune modulation and reducing inflammation in both supplement treated groups. Significant changes were observed via IL-6R signaling in the metabolic profiles of both groups compared to control and no significant differences when compared to each other. In the liver, these 2 feed additives induced immunometabolic changes predominantly via the IL-6 receptor family signaling cascade. Differences between the 2 treated groups were predominantly in the metabolic pathways, centered around the mTOR pathway and the proteins AMPK, mTOR and S6K, with a more anabolic phenotype following the addition of essential oils.

#957 The immunometabolic profile of human peritoneal macrophages during peritoneal dialysis and its relation to systemic cardiovascular effects

Abstract Background and Aims Patients with end-stage kidney disease (ESKD) treated with peritoneal dialysis (PD) exhibit a high risk of heart failure (HF). This largely concerns HF with a preserved ejection fraction (HFpEF). Uremic toxins, oxidative stress and systemic inflammation related to ESKD contribute to this HFpEF phenotype, which may be aggravated by the daily administration of glucose-rich PD-fluids. These induce insulin resistance and formation of advanced glycaemic end products, resulting in microvascular injury and arteriosclerosis. A hallmark of HFpEF is the presence of profibrotic cardiac macrophages that aggravate fibrosis. In the peritoneum, the non-physiological high glucose concentrations trigger local oxidative stress, fibrosis and inflammation, processes alike those seen in HFpEF. While the role of macrophages in HFpEF is established, the involvement of human peritoneal macrophages (HPMs) in PD-induced peritoneal injury is largely unknown. We hypothesize that HPMs, chronically exposed to the glucose-rich fluids, exhibit an inflammation-driven immunometabolic profile. This may contribute to cardiovascular (CV)-risk in PD-treated patients. We present preliminary results on the isolation of HPMs from PD effluent (PDE) and a detailed protocol to establish the immunometabolic profile of HPMs. These profiles will subsequently be related to cardiac function (left ventricular global longitudinal strain (LV-GLS), an echocardiographic measure of HFpEF) and parameters of systemic inflammation. Method In 15 adult PD-treated patients we will prospectively perform cardiac echography, draw a blood sample and collect PDE for HPM isolation. To obtain control HPMs a peritoneal saline flush will be collected from 5 adult patients with non-metastasized colon cancer during a routine diagnostic laparoscopy. HPMs will be isolated from the PDE and saline by centrifugation, followed by freezing for storage. We compared fresh and thawed cells of a PDE-sample to evaluate the impact of storage on HPM phenotype and functionality, respectively using flow cytometry and measurement of IL-6 production, with and without a lipopolysaccharide (LPS) challenge. In-depth HPM characterization will be performed by measuring glucose and lactate, conducting metabolic flux analysis, assessing glycolysis and mitochondrial characteristics using Seahorse®, and employing cytometry to evaluate reactive oxygen species and metabolic fuel preference. A phenotypical profile will be established using fluorescent probes and antibodies. To assess functionality, HPMs will be exposed in vitro to “M1” and “M2” inducers and we will use human monocyte-derived macrophages from healthy adult controls as a comparison. We will relate the immunometabolic, phenotypical and functional HPM characteristics to LV-GLS, blood cytokine (obtained with Bio-Plex multiplex) and blood immune profiles (obtained with cytometry) in PD-treated patients. Furthermore, we will compare the HPM characteristics of the PD-treated patients with the control group. Results Preliminary results of 6 patients show that we can isolate HPMs from the PDE with a yield of >5M cells. The phenotype and functionality of HPMs was evaluated both directly after isolation and after a freeze-thaw cycle. Flow cytometry showed high percentages of CD14+HLA-DR+CD64+ macrophages in both fresh and biobanked HPMs. IL-6 production was observed in both fresh and biobanked HPMs even without LPS-stimulation (Figure). Conclusion By successfully isolating and storing HPMs from the easily accessible PDE, we optimized the conditions to assess their immunometabolic characteristics. The proposed protocol not only aims to provide valuable insights into HPM phenotype and functionality, but also allows us to relate these to cardiac function and systemic inflammation. With this strategy, we aim to gain insight in the immunometabolic effects of PD on peritoneal immune cells and how these relate to CV-effects.

Immunometabolic actions of trabectedin and lurbinectedin on human macrophages: relevance for their anti-tumor activity.

In recent years, the central role of cell bioenergetics in regulating immune cell function and fate has been recognized, giving rise to the interest in immunometabolism, an area of research focused on the interaction between metabolic regulation and immune function. Thus, early metabolic changes associated with the polarization of macrophagesinto pro-inflammatoryorpro-resolving cells under different stimuli have been characterized. Tumor-associated macrophages are among the most abundant cells in the tumor microenvironment; however, it exists an unmet need to study the effect of chemotherapeutics on macrophage immunometabolism. Here, we use a systems biology approach that integrates transcriptomics and metabolomics to unveil the immunometabolic effects of trabectedin (TRB) and lurbinectedin (LUR), two DNA-binding agents with proven antitumor activity. Our results show that TRB and LUR activate human macrophages toward a pro-inflammatory phenotype by inducing a specific metabolic rewiring program that includes ROS production, changes in the mitochondrial inner membrane potential, increased pentose phosphate pathway, lactate release, tricarboxylic acids (TCA) cycle, serine and methylglyoxal pathways in human macrophages. Glutamine, aspartate, histidine, and proline intracellular levels are also decreased, whereas oxygen consumption is reduced. The observed immunometabolic changes explain additional antitumor activities of these compounds and open new avenues to design therapeutic interventions that specifically target the immunometabolic landscape inthe treatment of cancer.

OR22-04-23 Immunometabolic Effects of Physicochemically-Distinct Dietary Fibers in Adults With Excess Body Weight: Towards Personalized Dietary Fiber Strategies

OR22-04-23 Immunometabolic Effects of Physicochemically-Distinct Dietary Fibers in Adults With Excess Body Weight: Towards Personalized Dietary Fiber Strategies

Butyrate Supplementation Exacerbates Myocardial and Immune Cell Mitochondrial Dysfunction in a Rat Model of Faecal Peritonitis.

Mitochondrial dysfunction and immune cell dysfunction are commonplace in sepsis and are associated with increased mortality risk. The short chain fatty acid, butyrate, is known to have anti-inflammatory effects and promote mitochondrial biogenesis. We therefore explored the immunometabolic effects of butyrate in an animal model of sepsis. Isolated healthy human volunteer peripheral mononuclear cells were stimulated with LPS in the presence of absence of butyrate, and released cytokines measured. Male Wistar rats housed in metabolic cages received either intravenous butyrate infusion or placebo commencing 6 h following faecal peritonitis induction. At 24 h, splenocytes were isolated for high-resolution respirometry, and measurement of mitochondrial membrane potential (MMP), reactive oxygen species (mtROS), and intracellular cytokines (TNF alpha, IL-10) using flow cytometry. Isolated splenocytes from septic and septic butyrate treated rats were stimulated with LPS for 18 h and the effects of butyrate on cytokine release assessed. Ex vivo, butyrate (1.8 mM) reduced LPS-induced TNF alpha (p = 0.019) and IL-10 (p = 0.001) release by human PBMCs. In septic animals butyrate infusion reduced the respiratory exchange ratio (p < 0.001), consistent with increased fat metabolism. This was associated with a reduction in cardiac output (p = 0.001), and increased lactate (p = 0.031) compared to placebo-treated septic animals (p < 0.05). Butyrate treatment was associated with a reduction in splenocyte basal respiration (p = 0.077), proton leak (p = 0.022), and non-mitochondrial respiration (p = 0.055), and an increase in MMP (p = 0.007) and mtROS (p = 0.027) compared to untreated septic animals. Splenocyte intracellular cytokines were unaffected by butyrate, although LPS-induced IL-10 release was impaired (p = 0.039). In summary, butyrate supplementation exacerbates myocardial and immune cell mitochondrial dysfunction in a rat model of faecal peritonitis.

Differential Immunometabolic Effects of High-Fat Diets Containing Coconut, Sunflower, and Extra Virgin Olive Oils in Female Mice.

To compare the effects of three high-fat diets (HFDs) based on coconut, sunflower, or extra virgin olive oils (EVOOs) on adipose tissue, metabolism, and inflammation. Mice are fed for 16weeks on their respective HFD. HFD based on coconut oil produces significantly lower body weight than EVOO- or sunflower oil-based HFDs. Furthermore, the coconut oil HFD leads to metabolic disturbances such as reduction of circulating leptin and adiponectin concentrations, hypertriglyceridemia, hepatomegaly, and liver triglyceride accumulation. Likewise, this diet produces an increase in serum pro-inflammatory cytokines (interleukin 6 [IL-6] and tumor necrosis factor-α [TNF-α]). In white (WAT) and brown (BAT) adipose tissue, the HFD based on coconut oil does not cause significant changes in the expression of studied proteins related to thermogenesis (uncoupling protein 1 [UCP-1]), mitochondrial biogenesis, and browning (peroxisome proliferator-activated receptor-γ coactivator 1α [PGC-1α] and nuclear factor E2-related factor 2 [Nrf2]). However, the HFD based on EVOO induces upregulation of UCP-1, PGC-1α, and Nrf2 expression in BAT, increases the expression of UCP-1 and PGC-1α in inguinal WAT, and enhances the expression of PGC-1α in epididymal WAT. An HFD based on coconut oil could reduce circulating leptin and adiponectin concentrations, increase the liver fat content, raise serum triglycerides, and promote inflammation by increasing circulating pro-inflammatory cytokines, while an EVOO-based HFD could increase thermogenic activity.

IgM-associated gut bacteria in obesity and type 2 diabetes in C57BL/6 mice and humans

Aims/hypothesisIgM is the primary antibody produced by B cells and we hypothesise that IgM antibodies to gut microbiota may play a role in immunometabolism in obesity and type 2 diabetes. To test our hypothesis, we used B6 mice deficient in activation-induced cytidine deaminase (Aid−/− [also known as Aicda−/−]) which secrete only IgM antibodies, and human faecal samples.MethodsWe studied the immunometabolic effects and gut microbial changes in high-fat-diet-induced obesity (HFDIO) in Aid−/− B6 mice compared with wild-type mice. To determine similarities between mice and humans, human stool samples were collected from children and adolescents who were obese with normal glucose tolerance (NGT), obese with glucose intolerance (IGT), or obese and newly diagnosed with type 2 diabetes, for faecal microbiota transplant (FMT) into germ-free (GF) B6 mice and we assessed IgM-bound bacteria and immune responses.ResultsCompared with wild-type mice, Aid−/− B6 mice developed exacerbated HFDIO due to abundant levels of IgM. FMT from Aid−/− B6 to GF B6 mice promoted greater weight gain in recipient mice compared with FMT using wild-type mouse faecal microbiota. Obese youth with type 2 diabetes had more IgM-bound gut bacteria. Using the stools from the obese youth with type 2 diabetes for FMT to GF B6 mice, we observed that the gut microbiota promoted body weight gain and impaired glucose tolerance in the recipient GF B6 mice. Importantly, some clinical features of these obese young individuals were mirrored in the GF B6 mice following FMT.Conclusions/interpretationOur results suggest that IgM-bound gut microbiota may play an important role in the immuno-pathogenesis of obesity and type 2 diabetes, and provide a novel link between IgM in obesity and type 2 diabetes in both mice and humans.Data availabilityThe 16s rRNA sequencing datasets supporting the current study have been deposited in the NCBI SRA public repository (https://www.ncbi.nlm.nih.gov/sra; accession no. SAMN18796639).Graphical abstract

Caloric restriction in humans reveals immunometabolic regulators of health span.

The extension of life span driven by 40% caloric restriction (CR) in rodents causes trade-offs in growth, reproduction, and immune defense that make it difficult to identify therapeutically relevant CR-mimetic targets. We report that about 14% CR for 2 years in healthy humans improved thymopoiesis and was correlated with mobilization of intrathymic ectopic lipid. CR-induced transcriptional reprogramming in adipose tissue implicated pathways regulating mitochondrial bioenergetics, anti-inflammatory responses, and longevity. Expression of the gene Pla2g7 encoding platelet activating factor acetyl hydrolase (PLA2G7) is inhibited in humans undergoing CR. Deletion of Pla2g7 in mice showed decreased thymic lipoatrophy, protection against age-related inflammation, lowered NLRP3 inflammasome activation, and improved metabolic health. Therefore, the reduction of PLA2G7 may mediate the immunometabolic effects of CR and could potentially be harnessed to lower inflammation and extend the health span.

The Effect of Tuberculosis Antimicrobials on the Immunometabolic Profiles of Primary Human Macrophages Stimulated with Mycobacterium tuberculosis.

Tuberculosis (TB) remains a global health challenge. Patients with drug-sensitive and drug-resistant TB undergo long, arduous, and complex treatment regimens, often involving multiple antimicrobials. While these drugs were initially implemented based on their bactericidal effects, some studies show that TB antimicrobials can also directly affect cells of the immune system, altering their immune function. As use of these antimicrobials has been the mainstay of TB therapy for over fifty years now, it is more important than ever to understand how these antimicrobials affect key pathways of the immune system. One such central pathway, which underpins the immune response to a variety of infections, is immunometabolism, namely glycolysis and oxidative phosphorylation (OXPHOS). We hypothesise that in addition to their direct bactericidal effect on Mycobacterium tuberculosis (Mtb), current TB antimicrobials can modulate immunometabolic profiles and alter mitochondrial function in primary human macrophages. Human monocyte-derived macrophages (hMDMs) were differentiated from PBMCs isolated from healthy blood donors, and treated with four first-line and six second-line TB antimicrobials three hours post stimulation with either iH37Rv-Mtb or lipopolysaccharide (LPS). 24 h post stimulation, baseline metabolism and mitochondrial function were determined using the Seahorse Extracellular Flux Analyser. The effect of these antimicrobials on cytokine and chemokine production was also assayed using Meso Scale Discovery Multi-Array technology. We show that some of the TB antimicrobials tested can significantly alter OXPHOS and glycolysis in uninfected, iH37Rv-Mtb, and LPS-stimulated hMDMs. We also demonstrate how these antimicrobial-induced immunometabolic effects are linked with alterations in mitochondrial function. Our results show that TB antimicrobials, specifically clofazimine, can modify host immunometabolism and mitochondrial function. Moreover, clofazimine significantly increased the production of IL-6 in human macrophages that were stimulated with iH37Rv-Mtb. This provides further insight into the use of some of these TB antimicrobials as potential host-directed therapies in patients with early and active disease, which could help to inform TB treatment strategies in the future.

Immunometabolic Modulatory Role of Naltrexone in BV-2 Microglia Cells.

Background: Naltrexone is an opioid receptor antagonist commonly used to treat opioid and alcohol dependence. The use of low dose naltrexone (LDN) was found to have anti-inflammatory properties for treatment of diseases such as fibromyalgia, Crohn’s disease, multiple sclerosis and regional pain syndromes. Related to its anti-neuroinflammatory properties, the mechanism of action is possibly mediated via Toll-like receptor 4 antagonism, which is widely expressed on microglial cells. The aim of the present study was to assess the immunometabolic effects of naltrexone on microglia cells in in vitro conditions. Methods: All experiments were performed in the BV-2 microglial cell line. The cells were treated with naltrexone at 100 μM concentrations corresponding to low dose for 24 h. Cell viability was assessed for every drug dose. To induce additional activation, the cells were pretreated with LPS and IFN-γ. Immunofluorescence was used to analyse the classical microglial activation markers iNOS and CD206, while Seahorse was used for real-time cellular metabolic assessments. mTOR activity measured over the expression of a major direct downstream target S6K was assessed using western blot. Results: LDN induced a shift from highly activated pro-inflammatory phenotype (iNOShighCD206low) to quiescent anti-inflammatory M2 phenotype (iNOSlowCD206high) in BV-2 microglia cells. Changes in the inflammatory profile were accompanied by cellular metabolic switching based on the transition from high glycolysis to mitochondrial oxidative phosphorylation (OXPHOS). LDN-treated cells were able to maintain a metabolically suppressive phenotype by supporting OXPHOS with high oxygen consumption, and also maintain a lower energetic state due to lower lactate production. The metabolic shift induced by transition from glycolysis to mitochondrial oxidative metabolism was more prominent in cells pretreated with immunometabolic modulators such as LPS and IFN-γ. In a dose-dependent manner, naltrexone also modulated mTOR/S6K expression, which underlies the cell metabolic phenotype regulating microglia immune properties and adaptation. Conclusion: By modulating the phenotypic features by metabolic switching of activated microglia, naltrexone was found to be an effective and powerful tool for immunometabolic reprogramming and could be a promising novel treatment for various neuroinflammatory conditions.

Chenopodium Quinoa and Salvia Hispanica Provide Immunonutritional Agonists to Ameliorate Hepatocarcinoma Severity under a High-Fat Diet.

Complex interactions between immunonutritional agonist and high fat intake (HFD), the immune system and finally gut microbiota are important determinants of hepatocarcinoma (HCC) severity. The ability of immunonutritional agonists to modulate major aspects such as liver innate immunity and inflammation and alterations in major lipids profile as well as gut microbiota during HCC development is poorly understood. 1H NMR has been employed to assess imbalances in saturated fatty acids, MUFA and PUFA, which were associated to variations in iron homeostasis. These effects were dependent on the botanical nature (Chenopodium quinoa vs. Salvia hispanica L.) of the compounds. The results showed that immunonutritional agonists’ promoted resistance to hepatocarcinogenesis under pro-tumorigenic inflammation reflected, at a different extent, in increased proportions of F4/80+ cells in injured livers as well as positive trends of accumulated immune mediators (CD68/CD206 ratio) in intestinal tissue. Administration of all immunonutritional agonists caused similar variations of fecal microbiota, towards a lower obesity-inducing potential than animals only fed a HFD. Modulation of Firmicutes to Bacteroidetes contents restored the induction of microbial metabolites to improve epithelial barrier function, showing an association with liver saturated fatty acids and the MUFA and PUFA fractions. Collectively, these data provide novel findings supporting beneficial immunometabolic effects targeting hepatocarcinogenesis, influencing innate immunity within the gut-liver axis, and providing novel insights into their immunomodulatory activity.

C. quinoa and S. hispanica L. Seeds Provide Immunonutritional Agonists to Selectively Polarize Macrophages.

Diet-related immunometabolic-based diseases are associated with chronic inflammation in metabolic tissues, and infiltrated macrophages have been suggested as mediators for tissue- damaging inflammation. Growing evidence implicates Chenopodium quinoa and Salvia hispanica L. as important contributors to immunonutritional health. However, the functional roles of the immunonutritional protease inhibitors (PPIs) found in these crops on the macrophages’ metabolic and phenotypic adaptation remain to be elucidated. The salt soluble fraction of proteins was extracted and analyzed confirming the presence of 11S and 2S albumin. The <30 kDa fraction of the extract from both crops was subjected to simulated gastrointestinal digestion, where (RP-LC-MS/MS analyses) polypeptides from 2S-type of proteins were found, along with the 2S albumin (13 kDa) for S. hispanica in the bioaccessible fraction (BAF). Using human-like macrophage cells to deepen our understanding of the modulatory effects of this BAF, FACS analyses revealed their potential as TLR4 agonists, favoring increased phenotypic CD68/CD206 ratios. The results of mitochondrial stress tests showed that cells increased oxygen consumption rates and non-mitochondrial respiration, confirming negligible deleterious effects on mitochondrial function. At molecular-level, adaptation responses shed light on changes showing biological correlation with TLR4 signaling. The resulting immunometabolic effects triggered by PPIs can be a part of a tailored nutritional intervention strategy in immunometabolic-based diseases.

Complementary Immunometabolic Effects of Exercise and PPARβ/δ Agonist in the Context of Diet-Induced Weight Loss in Obese Female Mice.

Regular aerobic exercise, independently of weight loss, improves metabolic and anti-inflammatory states, and can be regarded as beneficial in counteracting obesity-induced low-grade inflammation. However, it is still unknown how exercise alters immunometabolism in a context of dietary changes. Agonists of the Peroxisome Proliferator Activated-Receptor beta/delta (PPARβ/δ) have been studied this last decade as “exercise-mimetics”, which are potential therapies for metabolic diseases. In this study, we address the question of whether PPARβ/δ agonist treatment would improve the immunometabolic changes induced by exercise in diet-induced obese female mice, having switched from a high fat diet to a normal diet. 24 mice were assigned to groups according to an 8-week exercise training program and/or an 8-week treatment with 3 mg/kg/day of GW0742, a PPARβ/δ agonist. Our results show metabolic changes of peripheral lymphoid tissues with PPARβ/δ agonist (increase in fatty acid oxidation gene expression) or exercise (increase in AMPK activity) and a potentiating effect of the combination of both on the percentage of anti-inflammatory Foxp3+ T cells. Those effects are associated with a decreased visceral adipose tissue mass and skeletal muscle inflammation (TNF-α, Il-6, Il-1β mRNA level), an increase in skeletal muscle oxidative capacities (citrate synthase activity, endurance capacity), and insulin sensitivity. We conclude that a therapeutic approach targeting the PPARβ/δ pathway would improve obesity treatment.

Macrophage NCOR1 protects from atherosclerosis by repressing a pro-atherogenic PPARγ signature.

Nuclear receptors and their cofactors regulate key pathophysiological processes in atherosclerosis development. The transcriptional activity of these nuclear receptors is controlled by the nuclear receptor corepressors (NCOR), scaffolding proteins that form the basis of large corepressor complexes. Studies with primary macrophages demonstrated that the deletion of Ncor1 increases the expression of atherosclerotic molecules. However, the role of nuclear receptor corepressors in atherogenesis is unknown. We generated myeloid cell-specific Ncor1 knockout mice and crossbred them with low-density lipoprotein receptor (Ldlr) knockouts to study the role of macrophage NCOR1 in atherosclerosis. We demonstrate that myeloid cell-specific deletion of nuclear receptor corepressor 1 (NCOR1) aggravates atherosclerosis development in mice. Macrophage Ncor1-deficiency leads to increased foam cell formation, enhanced expression of pro-inflammatory cytokines, and atherosclerotic lesions characterized by larger necrotic cores and thinner fibrous caps. The immunometabolic effects of NCOR1 are mediated via suppression of peroxisome proliferator-activated receptor gamma (PPARγ) target genes in mouse and human macrophages, which lead to an enhanced expression of the CD36 scavenger receptor and subsequent increase in oxidized low-density lipoprotein uptake in the absence of NCOR1. Interestingly, in human atherosclerotic plaques, the expression of NCOR1 is reduced whereas the PPARγ signature is increased, and this signature is more pronounced in ruptured compared with non-ruptured carotid plaques. Our findings show that macrophage NCOR1 blocks the pro-atherogenic functions of PPARγ in atherosclerosis and suggest that stabilizing the NCOR1-PPARγ binding could be a promising strategy to block the pro-atherogenic functions of plaque macrophages and lesion progression in atherosclerotic patients.

Leptin in the regulation of the immunometabolism of adipose tissue-macrophages.

Obesity is a pandemic disease affecting around 15% of the global population. Obesity is a major risk factor for other conditions, such as type 2 diabetes and cardiovascular diseases. The adipose tissue is the main secretor of leptin, an adipokine responsible for the regulation of food intake and energy expenditure. Obese individuals become hyperleptinemic due to increased adipogenesis. Leptin acts through the leptin receptor and induces several immunometabolic changes in different cell types, including adipocytes and Mϕs. Adipose tissue resident Mϕs (ATMs) are the largest leukocyte population in the adipose tissue and these ATMs are in constant contact with the excessive leptin levels secreted in obese conditions. Leptin activates both theJAK2-STAT3and thePI3K-AKT-mTORpathways. The activation of these pathways leads to intracellular metabolic changes, with increased glucose uptake, upregulation of glycolytic enzymes, and disruption of mitochondrial function, as well as immunologic alterations, such as increased phagocytic activity and proinflammatory cytokines secretion. Here, we discuss the immunometabolic effects of leptin in Mϕs and how hyperleptinemia can contribute to thelow-gradesystemic inflammation in obesity.

Metabolic Targets for Improvement of Allogeneic Hematopoietic Stem Cell Transplantation and Graft-vs.-Host Disease.

Utilization of the adaptive immune system against malignancies, both by immune-based therapies to activate T cells in vivo to attack cancer and by T-cell therapies to transfer effector cytolytic T lymphocytes (CTL) to the cancer patient, represent major novel therapeutic advancements in oncologic therapy. Allogeneic hematopoietic stem cell (HSC) transplantation (HSCT) is a form of cell-based therapy, which replaces the HSC in the patient's bone marrow but also serves as a T-cell therapy due to the Graft-vs.-leukemia (GVL) effect mediated by donor T cells transferred with the graft. Allogeneic HSCT provides one potentially curative option to patients with relapsed or refractory leukemia but Graft-vs.-Host-Disease (GVHD) is the main cause of non-relapse mortality and limits the therapeutic benefit of allogeneic HSCT. Metabolism is a common cellular feature and has a key role in the differentiation and function of T cells during the immune response. Naïve T cells and memory T cells that mediate GVHD and GVL, respectively, utilize distinct metabolic programs to obtain their immunological and functional specification. Thus, metabolic targets that mediate immunosuppression might differentially affect the functional program of GVHD-mediating or GVL-mediating T cells. Components of the innate immune system that are indispensable for the activation of alloreactive T cells are also subjected to metabolism-dependent regulation. Metabolic alterations have also been implicated in the resistance to chemotherapy and survival of malignant cells such as leukemia and lymphoma, which are targeted by GVL-mediating T cells. Development of novel approaches to inhibit the activation of GVHD-specific naïve T cell but maintain the function of GVL-specific memory T cells will have a major impact on the therapeutic benefit of HSCT. Here, we will highlight the importance of metabolism on the function of GVHD-inducing and GVL-inducing alloreactive T cells as well as on antigen presenting cells (APC), which are required for presentation of host antigens. We will also analyze the metabolic alterations involved in the leukemogenesis which could differentiate leukemia initiating cells from normal HSC, providing potential therapeutic opportunities. Finally, we will discuss the immuno-metabolic effects of key drugs that might be repurposed for metabolic management of GVHD without compromising GVL.

Small, Thin Graphene Oxide Is Anti-inflammatory Activating Nuclear Factor Erythroid 2-Related Factor 2 via Metabolic Reprogramming.

Graphene oxide (GO), an oxidized form of graphene, has potential applications in biomedical research. However, how GO interacts with biological systems, including the innate immune system, is poorly understood. Here, we elucidate the effects of GO sheets on macrophages, identifying distinctive effects of GO on the inflammatory phenotype. Small, thin (s)-GO dose-dependently inhibited release of interleukin (IL)-1β and IL-6 but not tumor necrosis factor α. NLRP3 inflammasome and caspase-1 activation was not affected. The effect of s-GO was pretranslational, as s-GO blocked Toll-like receptor 4-dependent expression of Il1b and Il6 but not Nlrp3 or Tnf mRNA transcripts. s-GO was internalized by immortalized bone-marrow-derived macrophages, suggesting a potential intracellular action. Uptake of polystyrene beads with similar lateral dimensions and surface charge did not phenocopy the effects of s-GO, suggesting that s-GO-mediated inhibition of interleukin expression was not simply due to particle phagocytosis. RNA-Seq analysis established that s-GO had profound effects on the immunometabolism of the cells, leading to activation of the transcription factor nuclear factor erythroid 2-related factor 2, which inhibited expression of cytokines such as IL-1β and IL-6. Thus, we have identified immunometabolic effects of GO that reveal another dimension to its effects on cells. These findings suggest that s-GO may be used as a valuable tool to generate further insights into inflammatory mechanisms and indicate its potential applications in biomedicine.

Immunometabolic regulation by triterpenes of Eucalyptus tereticornis in adipose tissue cell line models

Eucalyptus tereticornis Sm (Myrtaceae) is a plant used in traditional medicine to control obesity, insulin resistance and diabetes. Chronic adipose tissue inflammation is involved in generating insulin resistance, the greatest risk factor in developing type 2 diabetes mellitus and cardiovascular disease. In the present study, a mixture of triterpenes, as obtained from the starting plant material, was evaluated in inflamed adipose tissue cells models. Our goal is to advance into the understanding, at the cellular level, of the immunometabolic effects of the triterpene mixes from Eucalyptus tereticornis in in vitro models of mouse and human adipose tissues. Triterpene mixes were obtained from Eucalyptus tereticornis leaves by organic extraction. The major compounds of these mixes were identified by 1H NMR and 13C NMR in addition to HPLC using primary and secondary standards of ursolic acid, oleanolic acid and ursolic acid lactone. To provide an approach for evaluating the cellular and molecular mechanisms through which triterpene mixes act to modify the metabolic processes associated with obesity, mouse macrophage and adipocyte cell lines, human macrophage cell line and primary culture of human adipocytes were used as models. Adipocytes treated with the two natural chemically characterized triterpene mixes partially reduce lipogenesis and leptin expression. Additionally, an increase in the transcriptional expression of PPARγ, and C/EBPα is observed. In macrophages, these triterpene mixes, decrease the transcriptional and translational expression of pro-inflammatory cytokines, such as interleukin-6 (IL-6), interleukin 1β (IL-1β) and tumoral necrosis factor α (TNFα). Conditioned medium of 3T3-L1 adipocytes treated with the triterpene mix shows a stronger anti-inflammatory response on activated J774A.1 macrophages. The mixtures of the three triterpenes in the proportions obtained from the plant material may act on different components of the cell, generating a different response, which, in some cases, is more powerful than that seen when exposure to only two triterpenes. It makes this three triterpenes mix a good phytotherapeutic prototype for pathologies as complex as those associated with obesity.

Saroglitazar reduces obesity and associated inflammatory consequences in murine adipose tissue

Prevailing knowledge links chronic low-grade inflammation in the adipose tissue to obesity and its associated metabolic complications. In this study, we evaluated immunometabolic effects of a recently launched dual peroxisome proliferator-activated receptor (PPAR) α & γ agonist ‘Saroglitazar’ in a mouse model of diet-induced obesity (DIO). Body composition analysis revealed that saroglitazar treatment promoted hepatic weight gain, while attenuated epididymal white adipose tissue (eWAT) mass in DIO. In the eWAT of saroglitazar treated mice, histological analysis showed reduced adipocyte hypertrophy and matrix deposition (picrosirius red staining). Immunological profiling of stromal vascular fraction isolated from eWAT showed decreased pro-inflammatory cells (M1 macrophages, CD4 and CD8 T-cells) and increased anti-inflammatory M2 macrophages. Gene expression and western blot analysis suggested that saroglitazar promoted energy expenditure machinery and attenuated inflammatory as well as fibrotic markers in eWAT during DIO. In conclusion, for the first time we are reporting immunometabolic effects of dual PPARα & γ agonist saroglitazar in DIO and insulin resistance (IR). Saroglitazar exerted its beneficial effects on adipose tissue by limiting, diet-induced adipose tissue dysfunction, adipocyte hypertrophy, adipocyte cell damage and extracellular matrix deposition in obesity.