Immunometabolism: From basic mechanisms to translation

Metabolic heterogeneity in tumor cells impacts immunology in lung squamous cell carcinoma

Metabolic processes are crucial in immune regulation, yet the impact of metabolic heterogeneity on immunological functions remains unclear. Integrating metabolomics into immunology allows the exploration of the interactions of multilayered features in the biological system and the molecular regulatory mechanism of these features. To elucidate such insight in lung squamous cell carcinoma (LUSC), we analyzed 106 LUSC tumor tissues. We performed high-resolution matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to obtain spatial metabolic profiles, and immunohistochemistry to detect tumor-infiltrating T lymphocytes (TILs). Unsupervised k-means clustering and Simpson's diversity index were employed to assess metabolic heterogeneity, identifying five distinct metabolic tumor subpopulations. Our findings revealed that TILs are specifically associated with metabolite distributions, not randomly distributed. Integrating a validation cohort, we found that heterogeneity-correlated metabolites interact with CD8+ TIL-associated genes, affecting survival. High metabolic heterogeneity was linked to worse survival and lower TIL levels. Pathway enrichment analyses highlighted distinct metabolic pathways in each subpopulation and their potential responses to chemotherapy. This study uncovers the significant impact of metabolic heterogeneity on immune functions in LUSC, providing a foundation for tailoring therapeutic strategies.

The Effects and Mechanisms of Botulinum Toxin Type A on Hypertrophic Scars and Keloids

BACKGROUND

Keloids and hypertrophic scars are characterized by pathologically excessive dermal fibrosis and aberrant wound healing. These pathological scars are characterized by continuous and histologically localized inflammation of the reticular dermis. Although several treatments have been used for hypertrophic scar and keloid, there is still no consensus and for the majority of patients, management is driven by individual clinical experience. Injection of intralesional botulinum toxin type A (BTX) was more effective in the treatment of hypertrophic scar and keloid than injection of placebo. However, little is known about the mechanism of BTX in the treatment of hypertrophic scar and keloid.

METHODS

We used mice wound healing model to track the response of fibrous repair. The histological changes of the fibrous repair were measured by H&E, Masson and immunohistochemical staining. The quantitative analysis macrophages and angiogenesis were measured by immunohistochemical staining. The expression of Th1- and Th2-associated cytokines was measured by qPCR. We also measured oxoglutarate dehydrogenase (OGDH) and pyruvate dehydrogenase (PDH) activity, OGDH positive cells and mRNA used enzyme activity assay kits, immunohistochemical staining and qPCR, respectively.

RESULTS

We discovered that BTX injection disrupted wound healing and fibrous repair, and reduced M1 macrophages infiltration and M2 macrophages polarization, while increased total macrophages number. BTX injection reduced Il1b, Il6 and TNF-alpha mRNA level, and induced Il13 and Il4 mRNA level. BTX injection reduced OGDH activity.

CONCLUSIONS

BTX alter the pattern of immunometabolism that change the phenotype of macrophages, which inhibits keloids and hypertrophic scars.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors   www.springer.com/00266 .

Targeting LAT1 with JPH203 to reduce TNBC proliferation and reshape suppressive immune microenvironment by blocking essential amino acid uptake

The competitive uptake of essential amino acids (EAAs) by breast cancer cells is associated with poor patient prognosis and the development of an immunosuppressive tumor microenvironment. L-type amino acid transporters, LAT1 (SLC7 A5) and LAT2 (SLC7 A8) are major mediators of EAAs transmembrane uptake and are overexpressed in some tumor tissues. However, the distribution and functional roles of these transporters across breast cancer subtypes have not been fully elucidated. This study aims to investigate the therapeutic potential of targeting EAA transporters, particularly LAT1, in triple-negative breast cancer (TNBC) and its role in remodeling the tumor immune microenvironment. The distribution of EAA transporters across breast cancer subtypes was analyzed using multi-omics data. The effects of LAT1 targeting on TNBC cell proliferation and EAA uptake were evaluated using SLC7 A5 knockout and LAT1 inhibitors in vitro experiments. A 4T1-BALB/c tumor-bearing mouse model with normal immune function was constructed to investigate the effects of LAT1 targeting on tumor growth and immune microenvironment remodeling in vivo. TNBC demonstrated a strong dependence on LAT1-mediated EAAs uptake. Targeting LAT1 limited the exogenous supply of EAAs, leading to amino acid starvation, cell cycle arrest, and increased apoptosis in TNBC cells. The in vivo experiments, using a 4T1-BALB/c tumor-bearing mouse model, showed that LAT1 targeting inhibited tumor growth and remodeled the immunosuppressive tumor microenvironment. Targeting LAT1 improved PD-L1-associated immune suppression and improved the efficacy of PD-1 antibody treatment, producing synergistic anti-tumor effects. This study highlights the therapeutic potential of targeting LAT1 in TNBC, particularly in remodeling the tumor immune microenvironment. The findings provide a promising strategy for immune combination therapy in TNBC.

Metabolic Homeostasis of Immune Cells Modulates Cardiovascular Diseases

Recent investigations into the mechanisms underlying inflammation have highlighted the pivotal role of immune cells in regulating cardiac pathophysiology. Notably, these immune cells modulate cardiac processes through alternations in intracellular metabolism, including glycolysis and oxidative phosphorylation, whereas the extracellular metabolic environment is changed during cardiovascular disease, influencing function of immune cells. This dynamic interaction between immune cells and their metabolic environment has given rise to the novel concept of "immune metabolism". Consequently, both the extracellular and intracellular metabolic environment modulate the equilibrium between anti- and pro-inflammatory responses. This regulatory mechanism subsequently influences the processes of myocardial ischemia, cardiac fibrosis, and cardiac remodeling, ultimately leading to a series of cardiovascular events. This review examines how local microenvironmental and systemic environmental changes induce metabolic reprogramming in immune cells and explores the subsequent effects of aberrant activation or polarization of immune cells in the progression of cardiovascular disease. Finally, we discuss potential therapeutic strategies targeting metabolism to counteract abnormal immune activation.

NLRP3 inflammasome-mediated premature immunosenescence drives diabetic vascular aging dependent on the induction of perivascular adipose tissue dysfunction

AIMS

The vascular aging process accelerated by type 2 diabetes mellitus (T2DM) is responsible for the elevated risk of associated cardiovascular diseases. Metabolic disorder-induced immune senescence has been implicated in multi-organ/tissue damage. Herein, we sought to determine the role of immunosenescence in diabetic vascular aging and to investigate the underlying mechanisms.

METHODS AND RESULTS

Aging hallmarks of the immune system appear prior to the vasculature in streptozotocin (STZ)/high-fat diet (HFD)-induced T2DM mice or db/db mice. Transplantation of aged splenocytes or diabetic splenocytes into young mice triggered vascular senescence and injury compared with normal control splenocyte transfer. RNA sequencing profile and validation in immune tissues revealed that the toll-like receptor 4-nuclear factor-kappa B-NLRP3 axis might be the mediator of diabetic premature immunosenescence. The absence of Nlrp3 attenuated immune senescence and vascular aging during T2DM. Importantly, senescent immune cells, particularly T cells, provoked perivascular adipose tissue (PVAT) dysfunction and alternations in its secretome, which in turn impair vascular biology. In addition, senescent immune cells may uniquely affect vasoconstriction via influencing PVAT. Lastly, rapamycin alleviated diabetic immune senescence and vascular aging, which may be partly due to NLRP3 signalling inhibition.

CONCLUSION

These results indicated that NLRP3 inflammasome-mediated immunosenescence precedes and drives diabetic vascular aging. The contribution of senescent immune cells to vascular aging is a combined effect of their direct effects and induction of PVAT dysfunction, the latter of which can uniquely affect vasoconstriction. We further demonstrated that infiltration of senescent T cells in PVAT was increased and associated with PVAT secretome alterations. Our findings suggest that blocking the NLRP3 pathway may prevent early immunosenescence and thus mitigate diabetic vascular aging and damage, and targeting senescent T cells or PVAT might also be the potential therapeutic approach.

Identification of a chromatin regulator signature and potential candidate drugs for primary open-angle glaucoma

AIMS

This research aims to establish a chromatin regulator (CR) signature to provide new epigenetic insights into the pathogenesis of primary open-angle glaucoma (POAG).

MATERIALS & METHODS

The expression profile of CRs in trabecular meshwork (TM) tissues was analyzed by bioinformatics analysis; The selected hub CRs were further verified by cell experiments.

RESULTS

We found the immune microenvironment of the TMwas changed in POAG patients and identified 3 differentially expressed CRs that were relevant to immunity. Then, we successfully constructed and proved a predicted signature based on these 3 CRs, which could effectively predict the risk of POAG. The genes co-expressed with these 3 CRs and miRNAs with are gulatory relationship were identified, and a miRNA-hub CR network was successfully constructed. The results of the Gene Set Enrichment analysis indicated that these 3 hub CRs were all associated with neurodegenerative diseases. Moreover, the human trabecular meshwork cell (HTMC) oxidative stress model was constructed, and KDM5B was significantly down-regulated in this cell model. Finally, we found 10 agents that might be helpful for patients with POAG.

CONCLUSIONS

Dysregulation of CR expression in TM tissues may be involved in the occurrence and progression of POAG through multiple mechanisms.

Inflammatory markers after supplementation with marine n-3 or plant n-6 PUFAs: A randomized double-blind crossover study

Omega-3 (n-3) (e.g., EPA/DHA) and omega-6 (n-6) (e.g., linoleic acid [LA]) FAs are suggested to have opposite effects on inflammation, but results are inconsistent and direct comparisons of n-3 and n-6 are lacking. In a double-blind, randomized, and crossover study, females (n = 16) and males (n = 23) aged 30-70 years with abdominal obesity were supplemented with 3-4 g/d EPA/DHA (fish oil) or 15-20 g/d LA (safflower oil) for 7 weeks, with a 9-week washout phase. Cytokines and chemokines (multiplex assay), acute-phase proteins (MALDI-TOF mass spectrometry), endothelial function (vascular reaction index), blood pressure, FA composition (red blood cell membranes/serum/adipose tissue, GC-MS/MS), and adipose gene expression (microarrays, quantitative PCR) were measured. While significant differences between treatments in relative change scores were found for systolic blood pressure (n-3 vs. n-6: -1.81% vs. 2.61%, P = 0.003), no differences between n-3 and n-6 were found for any circulatory inflammatory markers. However, compared with baseline, n-3 was followed by reductions in circulating TNF (-24.9%, P < 0.001), regulated upon activation, normal T cell expressed and secreted (-12.1%, P < 0.001), and macrophage inflammatory protein 1-beta (-12.5%, P = 0.014), and n-6 by lowered TNF (-18.8%, P < 0.001), regulated upon activation, normal T cell expressed and secreted (-7.37%, P = 0.027), monocyte chemoattractant protein-1 (-7.81%, P = 0.020), and macrophage inflammatory protein 1-beta (-14.2%, P = 0.010). Adipose tissue showed significant treatment differences in weight percent of EPA (n-3 vs. n-6: 50.2%∗ vs. -1.38%, P < 0.001, ∗: significant within-treatment change score), DHA (16.0%∗ vs. -3.67%, P < 0.001), and LA (-0.033 vs. 4.91%∗, P < 0.001). Adipose transcriptomics revealed overall downregulation of genes related to inflammatory processes after n-3 and upregulation after n-6, partly correlating with changes in circulatory markers. These data point to tissue-specific proinflammatory effects of high n-6 intake, but a net systemic anti-inflammatory effect as for n-3.

Analysis of Immunometabolic Profiles in Patients With Chronic Drug-Induced Liver Injury and Validation in Mice to Reveal Potential Mechanisms

BACKGROUND

The mechanism underlying chronic drug-induced liver injury (DILI) remains unclear. Immune activation is a common feature of DILI progression and is closely associated with metabolism. We explored the immunometabolic profile of chronic DILI and the potential mechanism of chronic DILI progression.

METHODS

Plasma and peripheral blood mononuclear cells from patients with chronic DILI were analyzed using multiplex immunoassays and untargeted metabolomics to reveal their immunometabolic profile. The effects and potential mechanisms of chronic DILI-related metabolite on acute or chronic liver injury induced by LPS or CCl4 in mice were investigated.

RESULTS

Patients with chronic DILI exhibited elevated plasma IL-6, IL-12p70, IL-15 and reduced IL-10 levels. The percentage of IL-12+ monocytes was higher, while that of CD206+ monocytes, IL-10+ monocytes, Th2, Treg, and IL-10+ CD4+ T cells were lower in patients with chronic DILI compared to those with acute DILI. We identified the most significantly increased metabolite in patients with chronic DILI was cis-aconitic acid (CAA). Administration of CAA can attenuate liver injury in mice with acute liver injury induced by LPS or CCl4 and promote the spontaneous resolution of liver fibrosis in mice with chronic live injury induced by CCl4. The protective mechanism of CAA against liver injury is associated with the inhibition of hepatic macrophage infiltration and polarization, which is achieved by inhibiting the secretion of neutrophil-derived IL-33 and subsequent phosphorylation of GATA3.

CONCLUSIONS

CAA, which is elevated in patients with chronic DILI, protects against liver injury by inhibiting hepatic macrophage infiltration and polarization through the suppression of the IL-33/GATA3 pathway, suggesting that CAA may serve as a potential target for regulating tissue repair in liver injury.

Exploring diagnostic m6A regulators in primary open-angle glaucoma: insight from gene signature and possible mechanisms by which key genes function

PURPOSE

The purpose of this study was to interrogate the potential role of N6-methyladenosine (m6A) regulators in the process of trabecular meshwork (TM) tissue damage in patients with primary open-angle glaucoma (POAG).

METHODS

Firstly, the expression profile of m6A regulators in TM tissues of POAG patients was comprehensively analyzed by bioinformatics analysis; Plasmid transfection and siRNA gene interference were used to enhance or weaken the expression levels of YTHDC2 in human trabecular meshwork cells (HTMCs); Cell migration ability was detected by transwell chamber assay; Immunofluorescence staining assay was used to evaluate the expression of extracellular matrix (ECM) related proteins.

RESULTS

Through the analysis of GSE27276 database, 5 m6A regulators with different expression in POAG were screened out. The results of random forest model showed that these 5 m6A regulators exhibited diagnostic potential and were characteristic genes of POAG. All POAG samples could be effectively divided into two groups based on the expression levels of these 5 hub m6A regulators. Immune cell infiltration analysis indicated that the levels of activated CD8+ T cells and regulatory T cells were different in the two subtypes. HTMC oxidative stress cell model and TGF-β2 stimulation cell model were further constructed to verify the expression of the aforementioned hub m6A regulators, and it was found that YTHDC2 mRNA showed the same expression trend in both models. The silencing of YTHDC2 enhanced the migration ability of HTMCs and increased the synthesis ability of ECM. However, when YTHDC2ΔYTH, which lacks the YTH domain, is overexpressed in HTMCs, there is no significant change in the ECM synthesis ability.

CONCLUSIONS

The differentially expressed m6A regulators in TM tissues may serve as potential diagnostic biomarkers for POAG. And, in HTMCs, the expression level of YTHDC2 mRNA was changed under oxidative stress or TGF-β2 intervention, and then exerted its regulation on cell migration and ECM synthesis capability through m6A modification, which may be an important part of the disease process of POAG.

Integrative analysis of genes provides insights into the molecular and immune characteristics of mitochondria-related genes in atherosclerosis

Atherosclerosis is a chronic inflammatory disease characterized by lipid accumulation in arterial walls. The role of the interplay between mitochondrial dysfunction and immune inflammation in atherosclerosis is still unclear. This study aimed to investigate the molecular characteristics and immune landscape of mitochondrial hub genes involved in atherosclerosis. Based on bioinformatics analysis, three hub Mitochondria-related DEGs (MitoDEGs), including OXCT1, UCP2, and CPT1B, were screened out and showed good diagnostic performance in identifying atherosclerosis patients and controls. Immune analysis demonstrated strong correlations between hub MitoDEGs and immune cells, such as macrophages and T cells. Additionally, the predicted transcription factors of these hub MitoDEGs were significantly enriched in Th17, Th1 and Th2 cell differentiation signaling pathways. Both cell and animal experiments confirmed the expression trends of OXCT1 and CPT1B observed in the bioinformatics analysis. These hub MitoDEGs may play an important role in coordinating mitochondrial metabolism in the immune inflammation of atherosclerosis.

Exploring the mechanism and drug candidates of alveolar echinococcosis affecting liver fibrosis through analysis of existing microarray data

Echinococcosis, a zoonotic disease, significantly impacts the liver, with alveolar echinococcosis (AE) often leading to liver fibrosis and, in severe cases, cirrhosis. However, the molecular mechanisms by which AE infection promotes liver fibrosis remain incompletely understood. This study utilized bioinformatic analysis of existing microarray data to explore the shared mechanisms between AE and liver fibrosis and to identify potential therapeutic drug candidates. We analyzed gene expression datasets to identify common differentially expressed genes (DEGs), followed by enrichment analyses using Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes databases to determine biological functions and pathways. A protein-protein interaction network was constructed, and key hub genes were identified using Cytoscape software. Immune cell infiltration was evaluated and correlated with hub gene expression. Transcription factors regulating DEGs were predicted using the TRRUST database, and drug-target interactions were explored using DrugBank. A total of 260 DEGs were identified, primarily associated with cell cycle regulation and immune response pathways. Ten hub genes (DLGAP5, AURKA, MELK, CCNB2, CCNA2, NUF2, BUB1B, BUB1, TOP2A, and CCNB1) were highlighted for their significant interconnectivity and functional relevance. Immune infiltration analysis revealed dysregulation in immune responses, and transcription factor analysis identified E2F3 as a key regulatory factor with decreased expression in both AE and liver fibrosis. Finally, 135 candidate drugs targeting these hub genes were identified, offering new insights into therapeutic strategies. This study provides a foundation for understanding the molecular mechanisms underlying AE-related liver fibrosis and highlights potential drug candidates for clinical exploration.

Protective effects of Mycobacterium vaccae ATCC 15483 against "Western"-style diet-induced weight gain and visceral adiposity in adolescent male mice

The prevalence of noncommunicable inflammatory disease is increasing in modern urban societies, posing significant challenges to public health. Novel prevention and therapeutic strategies are needed to effectively deal with this issue. One promising approach is leveraging microorganisms such as Mycobacterium vaccae ATCC 15483, known for its anti-inflammatory, immunoregulatory, and stress-resilience properties. This study aimed to assess whether weekly subcutaneous administrations of a whole-cell, heat-killed preparation of M. vaccae ATCC 15483 (eleven injections initiated one week before the onset of the diet intervention), relative to vehicle injections, in adolescent male C57BL/6N mice can mitigate inflammation associated with Western-style diet-induced obesity, which is considered a risk factor for a number of metabolic and inflammatory diseases. Our results show that treatment with M. vaccae ATCC 15483 prevented Western-style diet-induced excessive weight gain, visceral adipose tissue accumulation, and elevated plasma leptin concentrations. The Western-style diet, relative to a control diet condition, decreased alpha diversity and altered the community composition of the gut microbiome, increasing the Bacillota to Bacteroidota ratio (formerly referred to as the Firmicutes to Bacteroidetes ratio). Despite the finding that M. vaccae ATCC 15483 prevented Western-style diet-induced excessive weight gain, visceral adipose tissue accumulation, and elevated plasma leptin concentrations, it had no effect on the diversity or community composition of the gut microbiome, suggesting that it acts downstream of the gut microbiome to alter immunometabolic signaling. M. vaccae ATCC 15483 reduced baseline levels of biomarkers of hippocampal neuroinflammation and microglial priming, such as Nfkbia and Nlrp3, and notably decreased anxiety-like defensive behavioral responses. The current findings provide compelling evidence supporting the potential for M. vaccae ATCC 15483 as a promising intervention for prevention or treatment of adverse immunometabolic outcomes linked to the consumption of a Western-style diet and the associated dysbiosis of the gut microbiome.

Effects of natural products on macrophage immunometabolism: A new frontier in the treatment of metabolic diseases

Immunometabolic variations in macrophages critically influence their differentiation into pro-inflammatory or anti-inflammatory phenotypes, thereby contributing to immune homeostasis, defense against infection, and tissue repair. Dysregulation of macrophage immunometabolism has been closely implicated in several metabolic diseases, including obesity, type 2 diabetes mellitus (T2DM), non-alcoholic fatty liver disease (NAFLD), hypertension, atherosclerosis, and gout, which positions macrophages as potential therapeutic targets. Recently, several natural products that target macrophage metabolic pathways have shown significant efficacy in managing metabolic diseases; however, a systematic review of these findings has yet to be conducted. This study consolidates natural products with immunoregulatory properties, including flavonoids, phenols, terpenoids, and naphthoquinones, which can alleviate chronic inflammation associated with metabolic disorders by modulating macrophage metabolic pathways, such as aerobic glycolysis, oxidative phosphorylation (OXPHOS), and fatty acid oxidation (FAO). This review aims to elucidate the metabolic regulation of the immune system, analyze metabolic alterations in macrophage associated with metabolic diseases, and summarize the beneficial roles of natural products in immunometabolism, providing novel insights for the prevention and therapeutic management of metabolic diseases.

Targeting metabolic dysfunction of CD8 T cells and natural killer cells in cancer

The importance of metabolic pathways in regulating immune responses is now well established, and a mapping of the bioenergetic metabolism of different immune cell types is under way. CD8 T cells and natural killer (NK) cells contribute to cancer immunosurveillance through their cytotoxic functions and secretion of cytokines and chemokines, complementing each other in target recognition mechanisms. Several immunotherapies leverage these cell types by either stimulating their activity or redirecting their specificity against tumour cells. However, the anticancer activity of CD8 T cells and NK cells is rapidly diminished in the tumour microenvironment, closely linked to a decline in their metabolic capacities. Various strategies have been developed to restore cancer immunosurveillance, including targeting bioenergetic metabolism or genetic engineering. This Review provides an overview of metabolic dysfunction in CD8 T cells and NK cells within the tumour microenvironment, highlighting current therapies aiming to overcome these issues.

Metabolic Adaptations Rewire CD4 T Cells in a Subset-Specific Manner in Human Critical Illness with and without Sepsis

Host immunity in sepsis has features of hyperinflammation together with progressive immunosuppression, particularly among CD4 T cells, that can predispose to secondary infections and ineffectual organ recovery. Metabolic and immunologic dysfunction are archetypal findings in critically ill patients with sepsis, but whether these factors are mechanistically linked remains incompletely defined. We characterized functional metabolic properties of human CD4 T cells from critically ill patients with and without sepsis and healthy adults. CD4 T cells in critical illness showed increased subset-specific metabolic plasticity, with regulatory T cells (Tregs) acquiring glycolytic capacity that stabilized suppressive markers FOXP3 and TIGIT and correlated with clinical illness severity. Single-cell transcriptomics identified differential kynurenine metabolism in Tregs, which was validated ex vivo as a mechanism of Treg glycolytic adaptation and suppressive rewiring. These findings underscore immunometabolic dysfunction as a driver of CD4 T cell remodeling in sepsis and suggest therapeutic avenues to restore an effective immune response.

Mitochondrial fatty acid oxidation regulates monocytic type I interferon signaling via histone acetylation

Although lipid-derived acetyl-coenzyme A (CoA) is a major carbon source for histone acetylation, the contribution of fatty acid β-oxidation (FAO) to this process remains poorly characterized. To investigate this, we generated mitochondrial acetyl-CoA acetyltransferase 1 (ACAT1, distal FAO enzyme) knockout macrophages. 13C-carbon tracing confirmed reduced FA-derived carbon incorporation into histone H3, and RNA sequencing identified diminished interferon-stimulated gene expression in the absence of ACAT1. Chromatin accessibility at the Stat1 locus was diminished in ACAT1-/- cells. Chromatin immunoprecipitation analysis demonstrated reduced acetyl-H3 binding to Stat1 promoter/enhancer regions, and increasing histone acetylation rescued Stat1 expression. Interferon-β release was blunted in ACAT1-/- and recovered by ACAT1 reconstitution. Furthermore, ACAT1-dependent histone acetylation required an intact acetylcarnitine shuttle. Last, obese subjects' monocytes exhibited increased ACAT1 and histone acetylation levels. Thus, our study identifies an intriguing link between FAO-mediated epigenetic control of type I interferon signaling and uncovers a potential mechanistic nexus between obesity and type I interferon signaling.

The Potential Inflammatory Role of IL-6 Signalling in Perturbing the Energy Metabolism Function by Stimulating the Akt-mTOR Pathway in Jurkat T Cells

Numerous studies have reported that increased interleukin 6 (IL-6) and soluble IL-6 receptor (sIL-6) levels induce inflammatory conditions. However, the exact mechanisms by which IL-6 drives inflammatory conditions remain unclear. Therefore, we investigated the potential role of IL-6/sIL-6R in inducing energy metabolism, including glycolysis, oxidative phosphorylation, lactate secretion and Akt/mTOR phosphorylation, in Jurkat cells, and whether IL-6 would increase the risk of developing inflammatory conditions due to the high metabolic profile of the T cells. Jurkat CD4 T-cell lines were stimulated with IL-6/sIL-6R for 24 h prior to 48-h stimulation with anti-CD3/CD28. Lactate secretion, glycolysis and oxidative phosphorylation levels were characterized using the Seahorse XF analyser. The Akt and mTOR phosphorylation status was detected using Western blotting. IL-6/sIL-6R significantly induced glycolysis and oxidative phosphorylation and their related parameters, including glycolytic capacity and maximal respiration, followed by significantly increased lactate secretion. Akt and mTOR phosphorylation were increased, which could have resulted from energy metabolism. Here we show that IL-6 enhanced the metabolic profile of Jurkat cells. This effect could have consequences for the metabolism-related signalling pathways, including Akt and mTOR, suggesting that IL-6 might promote T-cell energy metabolism, where T-cell hyperactivity might increase the inflammatory disease risk. The findings should be validated using studies on primary cells isolated from humans.

Tibial cortex transverse transport surgery improves wound healing in patients with severe type 2 DFUs by activating a systemic immune response: a cross-sectional study

BACKGROUND

Tibial cortex transverse transport (TTT) surgery has become an ideal treatment for patients with type 2 severe diabetic foot ulcerations (DFUs), while conventional treatments are ineffective. Based on our clinical practice experience, the protective immune response from TTT surgery may play a role against infections to promote wound healing in patients with DFUs. Therefore, this research aimed to systematically study the specific clinical efficacy and the mechanism of TTT surgery.

MATERIALS AND METHODS

Between June 2022 and September 2023, 68 patients with type 2 severe DFUs were enrolled and therapized by TTT surgery in this cross-sectional and experimental study. Major clinical outcomes, including limb salvage rate and antibiotics usage rate, were investigated. Ten clinical characteristics and laboratory features of glucose metabolism and kidney function were statistically analyzed. Blood samples from six key time points of TTT surgery were collected for label-free proteomics and clinical immune biomarker analysis. Besides, tissue samples from three key time points were used for spatially resolved metabolomics and transcriptomics analysis, as well as applied to validate the key TTT-regulated molecules by reverse-transcription quantitative PCR.

RESULTS

Notably, 64.7% of patients did not use antibiotics during the entire TTT surgery. TTT surgery can achieve a high limb salvage rate of 92.6% in patients with unilateral or bilateral DFUs. Pathway analysis of a total of 252 differentially expressed proteins from the proteomic revealed that the immune response induced by TTT surgery at different stages was first comprehensively verified through multiomics combined with immune biomarker analysis. The function of upward transport was activating the systemic immune response, and wound healing occurs with downward transport. The spatial metabolic characteristics of skin tissue from patients with DFUs indicated downregulated levels of stearoylcarnitine and the glycerophospholipid metabolism pathway in skin tissue from patients with severe DFUs. Finally, the expressions of PRNP (prion protein) to activate the immune response, PLCB3 (phospholipase C beta 3) and VE-cadherin play roles in neovascularization, and PPDPF (pancreatic progenitor cell differentiation and proliferation factor), LAMC2 (laminin subunit gamma 2), and SPRR2G (small proline-rich protein 2G) to facilitate the developmental process mainly keratinocyte differentiation were statistically significant in skin tissues through transcriptomic and reverse-transcription quantitative PCR analysis.

CONCLUSION

TTT surgery demonstrates favorable outcomes for patients with severe type 2 DFUs by activating a systemic immune response, contributing to anti-infection, ulcer recurrence, and the limb salvage for unilateral or bilateral DFUs. The specific clinical immune responses, candidate proteins, genes, and metabolic characteristics provide directions for in-depth mechanistic research on TTT surgery. Further research and public awareness are needed to optimize TTT surgery in patients with severe type 2 DFUs.

The multifaceted modulation of mitochondrial metabolism in tumorigenesis

Changes in mitochondrial metabolism produce a malignant transformation from normal cells to tumor cells. Mitochondrial metabolism, comprising bioenergetic metabolism, biosynthetic process, biomolecular decomposition, and metabolic signal conversion, obviously forms a unique sign in the process of tumorigenesis. Several oncometabolites produced by mitochondrial metabolism maintain tumor phenotype, which are recognized as tumor indicators. The mitochondrial metabolism synchronizes the metabolic and genetic outcome to the potent tumor microenvironmental signals, thereby further promoting tumor initiation. Moreover, the bioenergetic and biosynthetic metabolism within tumor mitochondria orchestrates dynamic contributions toward cancer progression and invasion. In this review, we describe the contribution of mitochondrial metabolism in tumorigenesis through shaping several hallmarks such as microenvironment modulation, plasticity, mitochondrial calcium, mitochondrial dynamics, and epithelial-mesenchymal transition. The review will provide a new insight into the abnormal mitochondrial metabolism in tumorigenesis, which will be conducive to tumor prevention and therapy through targeting tumor mitochondria.

Impact of zinc on immunometabolism and its putative role on respiratory diseases

Zinc is the second most abundant trace mineral in the human body and plays a critical role in immune cell function and metabolism. Zinc deficiency impairs immune cell function and is associated with increased susceptibility to respiratory diseases, including pneumonia, influenza, and COVID-19. Zinc homeostasis, maintained by numerous zinc transporters and metal-binding proteins (ie, metallothionein), is essential for coordinating immune cell signaling, gene expression, and enzymatic activities in response to respiratory infections. This article highlights the emerging role of zinc in various aspects of immune function, particularly through its influence on cellular metabolism. Given the significant global burden of respiratory diseases, there is a need to identify effective nutritional interventions that could be readily leveraged to prevent and/or mitigate respiratory disease risk, particularly in older adults who are prone to zinc deficiency. However, the immunometabolic mechanisms underlying zinc's protective effects remain poorly characterized. Future research should focus on elucidating how micronutrients, such as zinc, can support changes in immune cell metabolism in response to infections. Such efforts will help determine how zinc metabolism and zinc intervention strategies may best be leveraged to prevent or mitigate respiratory disease.

Research Progress on Glycolysis Mechanism of Psoriasis

Psoriasis is a chronic inflammatory disease with a complex pathogenesis. Hyperplasia of glycolytic-dependent epidermal keratinocytes (KCs) is a new hallmark of psoriasis pathogenesis. Meanwhile, immune cells undergo metabolic reprogramming similar to KCs. Glycolysis provides energy for the proliferation of KCs, while it also releases lactic acid to facilitate the differentiation of immune cells. In turn, differentiated immune cells further promote KCs glycolysis by releasing inflammatory factors, thus forming an immunometabolism loop. The interaction between immune response and metabolic pathways jointly promotes the sustained proliferation of KCs and the secretion of various inflammatory factors by immune cells. Understanding the role of glycolysis in immunometabolism of psoriasis may provide new ideas for non-immunosuppressive treatment of psoriasis. This article aims to review the role of glycolysis in the pathogenesis of psoriasis and attempts to summarize the key enzymes and regulatory factors involved in psoriasis glycolysis, as well as their interactions. Finally, we discuss the pharmacological modulators of glycolysis in psoriasis.

BLOC1S1 Control of Vacuolar Organelle Fidelity Modulates Murine TH2 Cell Immunity and Allergy Susceptibility

BACKGROUND

The levels of biogenesis of lysosome organelles complex 1 subunit 1 (BLOC1S1) control mitochondrial and endolysosome organelle homeostasis and function. Reduced fidelity of these vacuolar organelles is increasingly being recognized as important in instigating cell-autonomous immune cell activation. We reasoned that exploring the role of BLOC1S1 in CD4+ T cells may further advance our understanding of regulatory events linked to mitochondrial and/or endolysosomal function in adaptive immunity.

METHODS

CD4+ T cells were analyzed from control and CD4+ T-cell-specific BLOC1S1 knockout mice. Polarization profiles were assayed using biochemical and molecular signatures, and signaling pathways were disrupted pharmacologically or via siRNA. Mouse models of airway and skin inflammation were generated by Ovalbumin and MC903 exposure, respectively.

RESULTS

TH2 regulator GATA3 and phosphorylated STAT6 were preferentially induced in BLOC1S1-depleted primary CD4+ T (TKO) cells. The levels of IL-4, IL-5, and IL-13 were markedly induced in the absence of BLOC1S1. At the organelle level, mitochondrial DNA leakage evoked cGAS-STING and NF-κB pathway activation with subsequent TH2 polarization. The induction of autophagy with rapamycin reduced cytosolic mtDNA and reversed these TH2 signatures. Furthermore, genetic knockdown of STING and NF-κB inhibition ameliorated this immune regulatory cascade in TKO cells. Finally, at a functional level, TKO mice displayed an increased susceptibility to allergic conditions, including dermatitis and allergic asthma.

CONCLUSIONS

BLOC1S1 depletion in mouse CD4+ T cells mediated disruption of mitochondrial integrity to initiate a predominant TH2-responsive phenotype via STING-NF-κB-driven signaling of the canonical TH2 regulatory program.

Apex1 safeguards genomic stability to ensure a cytopathic T cell fate in autoimmune disease models

T cells have a remarkable capacity to clonally expand, a process that is intricately linked to their effector activities. As vigorously proliferating T cell also incur substantial DNA lesions, how the dividing T cells safeguard their genomic integrity to allow the generation of T effector cells remains largely unknown. Here we report the identification of the apurinic/apyrimidinic endonuclease-1 (Apex1) as an indispensable molecule for the induction of cytopathic T effectors in mouse models. We demonstrate that conditional deletion of Apex1 in T cells resulted in a remarkable accumulation of baseless DNA sites in the genome of proliferating T cells, which further led to genomic instability and apoptotic cell death. Consequently, Apex1-deleted T cells failed to acquire any effector features after activation and failed to mediate autoimmune diseases and allergic tissue damages. Detailed mutational analyses pinpointed the importance of its endonuclease domain in the generation of T effector cells. We provide further evidence that inhibiting the base repair activities of Apex1 with chemical inhibitors similarly abrogated the induction of autoimmune diseases. Collectively, our study suggests that Apex1 serves as a gatekeeper for the generation of cytopathic T cells and that therapeutically targeting Apex1 may have important clinical implications in the treatment of autoimmune diseases.

Identification of markers correlating with mitochondrial function in myocardial infarction by bioinformatics

BACKGROUND

Myocardial infarction (MI), one of the most serious cardiovascular diseases, is also affected by altered mitochondrial metabolism and immune status, but their crosstalk is poorly understood. In this paper, we use bioinformatics to explore key targets associated with mitochondrial metabolic function in MI.

METHODS

The datasets (GSE775, GSE183272 and GSE236374) were from National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) in conjunction with mitochondrial gene data that were downloaded from the MitoCarta 3.0 database. Differentially expressed genes (DEGs) in the dataset were screened by ClusterGVis, Weighted Gene Co-Expression Network Analysis (WGCNA) and GEO2R, and functional enrichment was performed by Gene Set Enrichment Analysis (GSEA) and Kyoto Encyclopedia of Genomes (KEGG). Then mitochondria-associated DEGs (MitoDEGs) were obtained. Protein-protein interaction (PPI) networks were constructed to identify central MitoDEGs that are strongly associated with MI. The Cytoscape and miRWalk databases were then used to predict the transcription factors and target miRNAs of the central MitoDEG, respectively. Finally, the mouse model has been established to demonstrate the expression of MitoDEGs and their association with cardiac function.

RESULTS

MitoDEGs in MI were mainly involved in mitochondrial function and adenosine triphosphate (ATP) synthesis pathways. The 10 MI-related hub MitoDEGs were then obtained by eight different algorithms. Immunoassays showed a significant increase in monocyte macrophage and T cell infiltration. According to animal experiments, the expression trends of the four hub MitoDEGs (Aco2, Atp5a1, Ndufs3, and Ndufv1) were verified to be consistent with the bioinformatics results.

CONCLUSION

Our study identified key genes (Aco2, Atp5a1, Ndufs3, and Ndufv1) associated with mitochondrial function in myocardial infarction.

Engineering immunity using metabolically active polymeric nanoparticles

Immune system functions play crucial roles in both health and disease, and these functions are regulated by their metabolic programming. The field of immune engineering has emerged to develop therapeutic strategies, including polymeric nanoparticles (NPs), that can direct immune cell phenotype and function by directing immunometabolic changes. Precise control of bioenergetic processes may offer the opportunity to prevent undesired immune activity and improve disease-specific outcomes. In this review we discuss the role that polymeric NPs can play in shaping immunometabolism and subsequent immune system activity through particle-mediated delivery of metabolically active agents as either structural components or cargo.

Failure of metabolic checkpoint control during late-stage granulopoiesis drives neutropenia in reticular dysgenesis

ABSTRACT

Cellular metabolism is highly dynamic during hematopoiesis, yet the regulatory networks that maintain metabolic homeostasis during differentiation are incompletely understood. Herein, we have studied the grave immunodeficiency syndrome reticular dysgenesis caused by loss of mitochondrial adenylate kinase 2 (AK2) function. By coupling single-cell transcriptomics in samples from patients with reticular dysgenesis with a CRISPR model of this disorder in primary human hematopoietic stem cells, we found that the consequences of AK2 deficiency for the hematopoietic system are contingent on the effective engagement of metabolic checkpoints. In hematopoietic stem and progenitor cells, including early granulocyte precursors, AK2 deficiency reduced mechanistic target of rapamycin (mTOR) signaling and anabolic pathway activation. This conserved nutrient homeostasis and maintained cell survival and proliferation. In contrast, during late-stage granulopoiesis, metabolic checkpoints were ineffective, leading to a paradoxical upregulation of mTOR activity and energy-consuming anabolic pathways such as ribonucleoprotein synthesis in AK2-deficient cells. This caused nucleotide imbalance, including highly elevated adenosine monophosphate and inosine monophosphate levels, the depletion of essential substrates such as NAD+ and aspartate, and ultimately resulted in proliferation arrest and demise of the granulocyte lineage. Our findings suggest that even severe metabolic defects can be tolerated with the help of metabolic checkpoints but that the failure of such checkpoints in differentiated cells results in a catastrophic loss of homeostasis.

Identification of mitochondria-related genes as diagnostic biomarkers for diabetic nephropathy and their correlation with immune infiltration: New insights from bioinformatics analysis

BACKGROUND

Diabetic nephropathy (DN) is a common and severe microvascular complication of diabetes. Mitochondrial dysfunction and immune inflammation are important factors in the pathogenesis of DN. However, the specific mechanisms and their intricate interactions in DN remain unclear. Besides, there are no effective specific predictive or diagnostic biomarkers for DN so far. Therefore, this study aims to elucidate the role of mitochondrial-related genes and their possibility as predictive or diagnostic biomarkers, as well as their crosstalk with immune infiltration in the progression of DN.

METHODS

Based on the GEO database and limma R package, the differentially expressed genes (DEGs) of DN were identified. Mitochondrial-related DEGs (MitoDEGs) were then obtained by intersecting these DEGs with mitochondria-related genes from the MitoCarta 3.0 database. Subsequently, the candidate hub genes were further screened by gene co-expression network analysis (WGCNA), and verified mRNA levels of these genes by real-time quantitative PCR (qRT-PCR) in high-glucose-treated human proximal tubular (HK-2) cells. The verified hub genes were utilized to construct a combined diagnostic model for DN, with its diagnostic efficacy assessed across the GSE30122 and GSE96804 datasets. Additionally, the immune infiltration pattern in DN was assessed with the CIBERSORT algorithm, and the Nephroseq v5 database was used to analyze the correlation between hub genes and clinical features of DN.

RESULTS

Seven mitochondria-related candidate hub genes were screened from 56 MitoDEGs. Subsequently, the expression levels of six of them, namely EFHD1, CASP3, AASS, MPC1, NT5DC2, and BCL2A1, exhibited significant inter-group differences in the HK-2 cell model. The diagnostic model based on the six genes demonstrated good diagnostic efficacy in both training and validation sets. Furthermore, correlation analysis indicated that EFHD1 and AASS, downregulated in DN, are positively correlated with eGFR and negatively with serum creatinine. Conversely, CASP3, NT5DC2, and BCL2A1, upregulated in DN, show opposite correlations. In addition, spearman analysis revealed that the six hub genes were significantly associated with the infiltration of immune cells, including M1 and M2 macrophages, mast cells, resting NK cells, gamma delta T cells, and follicular helper T cells.

CONCLUSION

This study elucidated the characteristics of mitochondria-related genes and their correlation with immune cell infiltration in DN, providing new insights for exploring the pathogenesis of DN and facilitating the identification of new potential biomarkers and therapeutic targets.

Identification of immune-related hub genes and potential molecular mechanisms involved in COVID-19 via integrated bioinformatics analysis

COVID-19, caused by the SARS-CoV-2 virus, poses significant health challenges worldwide, particularly due to severe immune-related complications. Understanding the molecular mechanisms and identifying key immune-related genes (IRGs) involved in COVID-19 pathogenesis is critical for developing effective prevention and treatment strategies. This study employed computational tools to analyze biological data (bioinformatics) and a method for inferring causal relationships based on genetic variations, known as Mendelian randomization (MR), to explore the roles of IRGs in COVID-19. We identified differentially expressed genes (DEGs) from datasets available in the Gene Expression Omnibus (GEO), comparing COVID-19 patients with healthy controls. IRGs were sourced from the ImmPort database. We conducted functional enrichment analysis, pathway analysis, and immune infiltration assessments to determine the biological significance of the identified IRGs. A total of 360 common differential IRGs were identified. Among these genes, CD1C, IL1B, and SLP1 have emerged as key IRGs with potential protective effects against COVID-19. Pathway enrichment analysis revealed that CD1C is involved in terpenoid backbone biosynthesis and Th17 cell differentiation, while IL1B is linked to B-cell receptor signaling and the NF-kappa B signaling pathway. Significant correlations were observed between key genes and various immune cells, suggesting that they influence immune cell modulation in COVID-19. This study provides new insights into the immune mechanisms underlying COVID-19, highlighting the crucial role of IRGs in disease progression. These findings suggest that CD1C and IL1B could be potential therapeutic targets. The integrated bioinformatics and MR analysis approach offers a robust framework for further exploring immune responses in COVID-19 patients, as well as for targeted therapy and vaccine development.

Subcutaneous adipose tissue: Implications in dermatological diseases and beyond

Subcutaneous adipose tissue (SAT) is the deepest component of the three-layered cutaneous integument. While mesenteric adipose tissue-based immune processes have gained recognition in the context of the metabolic syndrome, SAT has been traditionally considered primarily for energy storage, with less attention to its immune functions. SAT harbors a reservoir of immune and stromal cells that significantly impact metabolic and immunologic processes not only in the skin, but even on a systemic level. These processes include wound healing, cutaneous and systemic infections, immunometabolic, and autoimmune diseases, inflammatory skin diseases, as well as neoplastic conditions. A better understanding of SAT immune functions in different processes, could open avenues for novel therapeutic interventions. Targeting SAT may not only address SAT-specific diseases but also offer potential treatments for cutaneous or even systemic conditions. This review aims to provide a comprehensive overview on SAT's structure and functions, highlight recent advancements in understanding its role in both homeostatic and pathological conditions within and beyond the skin, and discuss the main questions for future research in the field.

LGG promotes activation of intestinal ILC3 through TLR2 receptor and inhibits salmonella typhimurium infection in mice

Salmonella is a foodborne pathogen that causes disruption of intestinal mucosal immunity, leading to acute gastroenteritis in the host. In this study, we found that Salmonella Typhimurium (STM) infection of the intestinal tract of mice led to a significant increase in the proportion of Lacticaseibacillus, while the secretion of IL-22 from type 3 innate lymphoid cells (ILC3) increased significantly. Feeding Lacticaseibacillus rhamnosus GG (LGG) effectively alleviated the infection of STM in the mouse intestines. TLR2-/- mice experiments found that TLR2-expressing dendritic cells (DCs) are crucial for LGG's activation of ILC3. Subsequent in vitro experiments showed that heat-killed LGG (HK-LGG) could promote DCs to secrete IL-23, which in turn further promotes the activation of ILC3 and the secretion of IL-22. Finally, organoid experiments further verified that IL-22 secreted by ILC3 can enhance the intestinal mucosal immune barrier and inhibit STM infection. This study demonstrates that oral administration of LGG is a potential method for inhibiting STM infection.

OM-85 attenuates high-fat diet-induced obesity, insulin resistance, gut dysbiosis and nonalcoholic steatohepatitis in a murine model

BACKGROUND

Obesity is a global epidemic that is tied to a wide range of human disorders. Chronic consumption of a high-fat diet is linked to disruption of the intestinal microbiome, which drives obesity-related pathophysiology. Broncho-Vaxom® (OM-85), a bacterial lysate used for prophylaxis of recurrent respiratory tract infections, has both immunostimulatory and immunomodulatory functions.

METHODS

Male C57Bl/6 mice were maintained on normal control vs. high-fat diets for 8 weeks and treated or untreated with OM-85 or with the probiotic Lactobacillus plantarum, as a positive control. Mice were evaluated for weight gain, glucose tolerance, insulin tolerance, gut microbiome composition and non-alcoholic steatohepatitis (NASH).

RESULTS

High-fat diet mice developed obesity, insulin resistance, NASH and gut dysbiosis with a shift from the Bacteroidetes phylum, such as Bacteroidales order and Muribaculaceae family organisms to Firmicutes groups, such as the Clostridium and Blautia genuses. Treatment with OM-85 led to 1) prevention of obesity, 2) prevention of insulin resistance, 3) attenuation of NASH and 4) attenuation of gut dysbiosis, with decreased levels of the organisms mentioned above and increases in Verrucomicrobiae phylum organisms such as Akkermansia family microbes as well as Muribaculaceae organisms. These shifts in the gut microbiome predict favorable effects on the short chain fatty acid profile in the gut and increased integrity of the intestinal barrier. Pathway analysis showed that OM-85 decreases rates of carbohydrate metabolism, providing an additional mechanism whereby OM-85 prevents obesity.

CONCLUSION

Immune modulators such as OM-85 should be investigated for their potential therapeutic effects on metabolism.

Variants in inflammation-related genes influence the outcomes of physical exercise programs: A longitudinal study in Brazilian adolescents with overweight and obesity

The expansion of adipose tissue, characteristic of obesity, releases inflammatory cytokines, leading to metabolic disorders. Physical activity, on the other hand, promotes fat loss and changes inflammatory profile. This study aimed to investigate the associations of 20 gene variants (TLR2, TLR4, IL1B, IL6, NFKB1, TNF, NFKBIA, NLRC4, CARD8 and NEK7) with anthropometric and biochemical changes induced by physical exercise programs. Thus, 58 children and adolescents participated of the 12-week exercise programs. Parameters were collected before and after programs: body mass index, body fat percentage, LDL-C, HDL-C, triglycerides, total cholesterol, insulin, glucose, HOMA-IR and QUICKI. Changes in these parameters were calculated (final - initial measurements) for subsequent analyses. Linear regression analyses were performed to investigate associations between genotypes and changes in the analyzed parameters. We found associations between 14 variants in nine genes with anthropometrical and biochemical outcomes. Observing the distribution of the sample, the groups of individuals who responded less in relation to body fat and TG levels concentrated the highest scores of polygenic indexes as a result of a greater number of risk variants. In conclusion, some genotypes related to the inflammatory profile provided less favorable anthropometrical and biochemical outcomes in response to physical exercise programs.

The sedoheptulose kinase CARKL controls T-cell cytokine outputs and migration by promoting metabolic reprogramming

Background

Immunometabolism is a crucial determinant of immune cell function, influencing cellular activation and differentiation through metabolic pathways. The intricate interplay between metabolism and immune responses is highlighted by the distinct metabolic programs utilized by immune cells to support their functions. Of particular interest is the pentose phosphate pathway (PPP), a key metabolic pathway branching out of glycolysis that plays a pivotal role in generating NADPH and pentose sugars crucial for antioxidant defense and biosynthesis. The sedoheptulose kinase Carbohydrate Kinase-like protein (CARKL), an enzyme involved in the PPP, emerges as a critical regulator of cell metabolism and was previously shown to play a role in macrophage function.

Methods

This study delves into the impact of CARKL expression on T-cell functionality, revealing dynamic alterations in response to cellular activation. Notably, CARKL overexpression leads to significant metabolic shifts in T cells, affecting mitochondrial respiration, ATP production, and inflammatory cytokine profiles. Furthermore, CARKL modulation influences T-cell motility by regulating chemokine receptor expression, particularly compromising CXCR3 expression and impairing T-cell migration in response to specific chemokine signals.

Conclusions

These findings underscore the multifaceted role of CARKL as a metabolic regulator shaping T-cell responses. Overall, our data reveal the complex regulatory mechanisms orchestrated by CARKL in T-cell function, with implications for immune regulation. Further exploration of the molecular interactions between CARKL and metabolic reprogramming in T cells could provide valuable insights into immune regulation and potential therapeutic strategies.

Longitudinal mitochondrial bioenergetic signatures of blood monocytes and lymphocytes improve during treatment of drug-susceptible pulmonary tuberculosis patients Monocyte/lymphocyte bioenergetic signatures post-TB treatment

The impact of human pulmonary tuberculosis (TB) on the bioenergetic metabolism of circulating immune cells remains elusive, as does the resolution of these effects with TB treatment. In this study, the rates of oxidative phosphorylation (OXPHOS) and glycolysis in circulating lymphocytes and monocytes of patients with drug-susceptible TB at diagnosis, 2 months, and 6 months during treatment, and 12 months after diagnosis were investigated using extracellular flux analysis. At diagnosis, the bioenergetic parameters of both blood lymphocytes and monocytes of TB patients were severely impaired in comparison to non-TB and non-HIV-infected controls. However, most bioenergetic parameters were not affected by HIV status or glycemic index. Treatment of TB patients restored the % spare respiratory capacity (%SRC) of the circulating lymphocytes to that observed in non-TB and non-HIV infected controls by 12 months. Treatment also improved the maximal respiration of circulating lymphocytes and the %SRC of circulating monocytes of the TB patients. Notably, the differential correlation of the clinical and bioenergetic parameters of the monocytes and lymphocytes from the controls and TB patients at baseline and month 12 was consistent with improved metabolic health and resolution of inflammation following successful TB treatment. Network analysis of the bioenergetic parameters of circulating immune cells with serum cytokine levels indicated a highly coordinated immune response at month 6. These findings underscore the importance of metabolic health in combating TB, supporting the need for further investigation of the bioenergetic immunometabolism associated with TB infection for novel therapeutic approaches aimed at bolstering cellular energetics to enhance immune responses and expedite recovery in TB patients.

Coenzyme A fueling with pantethine limits autoreactive T cell pathogenicity in experimental neuroinflammation

BACKGROUND

Immune cell metabolism governs the outcome of immune responses and contributes to the development of autoimmunity by controlling lymphocyte pathogenic potential. In this study, we evaluated the metabolic profile of myelin-specific murine encephalitogenic T cells, to identify novel therapeutic targets for autoimmune neuroinflammation.

METHODS

We performed metabolomics analysis on actively-proliferating encephalitogenic T cells to study their overall metabolic profile in comparison to resting T cells. Metabolomics, phosphoproteomics, in vitro functional assays, and in vivo studies in experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), were then implemented to evaluate the effect of metabolic targeting on autoreactive T cell pathogenicity. Finally, we confirmed the translational potential of our targeting approach in human pro-inflammatory T helper cell subsets and in T cells from MS patients.

RESULTS

We found that autoreactive encephalitogenic T cells display an altered coenzyme A (CoA) synthesis pathway, compared to resting T cells. CoA fueling with the CoA precursor pantethine (PTTH) affected essential immune-related processes of myelin-specific T cells, such as cell proliferation, cytokine production, and cell adhesion, both in vitro and in vivo. Accordingly, pre-clinical treatment with PTTH before disease onset inhibited the development of EAE by limiting T cell pro-inflammatory potential in vivo. Importantly, PTTH also significantly ameliorated the disease course when administered after disease onset in a therapeutic setting. Finally, PTTH reduced pro-inflammatory cytokine production by human T helper 1 (Th1) and Th17 cells and by T cells from MS patients, confirming its translational potential.

CONCLUSION

Our data demonstrate that CoA fueling with PTTH in pro-inflammatory and autoreactive T cells may represent a novel therapeutic approach for the treatment of autoimmune neuroinflammation.

The Fourth Annual Symposium of the Midwest Aging Consortium

The Midwest Aging Consortium (MAC) has emerged as a critical collaborative initiative aimed at advancing our understanding of aging and developing strategies to combat the rising prevalence of age-related diseases. Founded in 2019, MAC brings together researchers from various disciplines and institutions across the Midwestern United States to foster interdisciplinary geroscience research. This report summarizes the highlights of the Fourth Annual Symposium of MAC, which was held at Iowa State University in May 2023. The symposium featured presentations on a wide array of topics, including studies on slow-aging animals, cellular senescence and senotherapeutics, the role of the immune system in aging, metabolic changes in aging, neuronal health in aging, and biomarkers for measuring the aging process. Speakers shared findings from studies involving a variety of animals, ranging from commonly used species such as mice, rats, worms, yeast, and fruit flies, to less-common ones like naked mole-rats, painted turtles, and rotifers. MAC continues to emphasize the importance of supporting emerging researchers and fostering a collaborative environment, positioning itself as a leader in aging research. This symposium not only showcased the current state of aging biology research but also highlighted the consortium's role in training the next generation of scientists dedicated to improving the healthspan and well-being of the aging population.

Immunometabolism: signaling pathways, homeostasis, and therapeutic targets

Immunometabolism plays a central role in sustaining immune system functionality and preserving physiological homeostasis within the organism. During the differentiation and activation, immune cells undergo metabolic reprogramming mediated by complex signaling pathways. Immune cells maintain homeostasis and are influenced by metabolic microenvironmental cues. A series of immunometabolic enzymes modulate immune cell function by metabolizing nutrients and accumulating metabolic products. These enzymes reverse immune cells' differentiation, disrupt intracellular signaling pathways, and regulate immune responses, thereby influencing disease progression. The huge population of immune metabolic enzymes, the ubiquity, and the complexity of metabolic regulation have kept the immune metabolic mechanisms related to many diseases from being discovered, and what has been revealed so far is only the tip of the iceberg. This review comprehensively summarized the immune metabolic enzymes' role in multiple immune cells such as T cells, macrophages, natural killer cells, and dendritic cells. By classifying and dissecting the immunometabolism mechanisms and the implications in diseases, summarizing and analyzing advancements in research and clinical applications of the inhibitors targeting these enzymes, this review is intended to provide a new perspective concerning immune metabolic enzymes for understanding the immune system, and offer novel insight into future therapeutic interventions.

The NLRP3 molecule influences the therapeutic effects of mesenchymal stem cells through Glut1-mediated energy metabolic reprogramming

INTRODUCTION

Numerous studies demonstrated that NLRP3 has been implicated in the pathogenesis of inflammatory bowel disease (IBD). Mesenchymal stem cells (MSCs) regulated the NLRP3 inflammasome, which has emerged as a novel therapeutic approach for treating IBD.

OBJECTIVES

The exact role of NLRP3 in regulating MSCs' function is unclear. Our study aimed to explore how NLRP3 affects the therapeutic effects of MSCs in colitis.

METHODS

We extracted MSCs from the bone marrow of C57BL/6 mice and Nlrp3 KO mice, and identified them using differentiation assays and flow cytometry. In vitro, Both WT MSCs and Nlrp3 KO MSCs were stimulated with inflammatory factor Lipopolysaccharide (LPS), and only WT MSCs were stimulated with varying concentrations of the NLRP3 inhibitor MCC950, then, quantified IL-10 levels in the supernatant. RNA-seq was performed to examine gene expression patterns and Seahorse was used to assess oxidative phosphorylation (OXPHOS) and glycolysis levels. Western blot was used to evaluate protein expression. In vivo, we treated DSS-induced colitis with either WT or Nlrp3 KO MSCs, monitoring weight, measuring colon length, and further evaluation. We also treated DSS-induced colitis with pretreated MSCs (BAY876, oe-Glut1, or oe-NLRP3), following the same experimental procedures as described above.

RESULTS

Our results demonstrate that Nlrp3 deletion did not affect MSC phenotypes, but rather promoted osteogenic differentiation. However, the absence of Nlrp3 reduced IL-10 production in MSCs in the presence of LPS, leading to impaired protection on DSS-induced colitis. Conversely, overexpression of NLRP3 promotes the production of IL-10, enhancing therapeutic effects. Further investigation revealed that Nlrp3 deficiency downregulated Glut1 expression and glycolysis activation in MSCs, resulting in decreased IL-10 production. Notably, overexpressing Glut1 in Nlrp3 KO MSCs restored their therapeutic effect that was previously dampened due to Nlrp3 deletion.

CONCLUSION

Our findings demonstrate that NLRP3 heightens the therapeutic effects of MSC treatment on DSS-induced colitis.

Early administration of Wumei Wan inhibit myeloid-derived suppressor cells via PI3K/Akt pathway and amino acids metabolism to prevent colitis-associated colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Wumei Wan (WMW), a traditional Chinese medicine prescription, has been proved to be effective in treating Colitis-associated colorectal cancer (CAC), but it has not been proven to be effective in different stages of CAC.

AIM OF THE STUDY

The purpose of our study is to investigate the therapeutic effect and mechanism of WMW on the progression of CAC.

MATERIALS AND METHODS

Azioximethane (AOM) and dextran sulfate sodium (DSS) were used to treat mice for the purpose of establishing CAC models. WMW was administered in different stages of CAC. The presentative chemical components in WMW were confirmed by LC-MS/MS under the optimized conditions. The detection of inflammatory cytokines in the serum and colon of mice were estimated by qRT-PCR and ELISA. The changes of T cells and myeloid-derived suppressor cells (MDSCs) in each group were detected by flow cytometry. The metabolic components in serum of mice were detected by UPLC-MS/MS. Expression of genes and proteins were detected by eukaryotic transcriptomics and Western blot to explore the key pathway of WMW in preventing CAC.

RESULTS

WMW had significant effect on inhibiting inflammatory responses and tumors during the early development stage of CAC when compared to other times. WMW increased the length of mice's colons, reduced the level of IL-1β, IL-6, TNF-α in colon tissues, and effectively alleviated colonic inflammation, and improved the pathological damage of colon tissues. WMW could significantly reduce the infiltration of MDSCs in the spleen, increase CD4+ T cells and CD8+ T cells in the spleen of CAC mice, and effectively reform the immune microenvironment in CAC mice. Transcriptomics analysis revealed that 2204 genes had different patterns of overlap in the colon tissues of mice between control group, AOM + DSS group, and early administration of WMW group. And KEGG enrichment analysis showed that PI3K/Akt signaling pathway, ECM-receptor interaction, IL-17 signaling pathway, MAPK signaling pathway, pancreatic secretion, thermogenesis, and Rap1 signaling pathway were all involved. The serum metabolomics results of WMW showed that the metabolic compositions of the control group, AOM + DSS group and the early stage of WMW were different, and 42 differential metabolites with the opposite trends of changes were screened. The metabolic pathways mainly included pyrimidine metabolism, glycine, serine and threonine metabolism, tryptophan metabolism, and purine metabolism. And amino acids and related metabolites may play an important role in WMW prevention of CAC.

CONCLUSION

WMW can effectively prevent the occurrence and development of CAC, especially in the initial stage. WMW can reduce the immune infiltration of MDSCs in the early stage. Early intervention of WMW can improve the metabolic disorder caused by AOM + DSS, especially correct the amino acid metabolism. PI3K/Akt signaling pathway was inhabited in early administration of WMW, which can regulate the amplification and function of MDSCs.

Metabolic Dysregulation and Metabolite Imbalances in Acute-on-chronic Liver Failure: Impact on Immune Status

Liver failure encompasses a range of severe clinical syndromes resulting from the deterioration of liver function, triggered by factors both within and outside the liver. While the definition of acute-on-chronic liver failure (ACLF) may vary by region, it is universally recognized for its association with multiorgan failure, a robust inflammatory response, and high short-term mortality rates. Recent advances in metabolomics have provided insights into energy metabolism and metabolite alterations specific to ACLF. Additionally, immunometabolism is increasingly acknowledged as a pivotal mechanism in regulating immune cell functions. Therefore, understanding the energy metabolism pathways involved in ACLF and investigating how metabolite imbalances affect immune cell functionality are crucial for developing effective treatment strategies for ACLF. This review methodically examined the immune and metabolic states of ACLF patients and elucidated how alterations in metabolites impact immune functions, offering novel perspectives for immune regulation and therapeutic management of liver failure.

Itaconate is a metabolic regulator of bone formation in homeostasis and arthritis

OBJECTIVES

Bone remodelling is a highly dynamic process dependent on the precise coordination of osteoblasts and haematopoietic-cell derived osteoclasts. Changes in core metabolic pathways during osteoclastogenesis, however, are largely unexplored and it is unknown whether and how these processes are involved in bone homeostasis.

METHODS

We metabolically and transcriptionally profiled cells during osteoclast and osteoblast generation. Individual gene expression was characterised by quantitative PCR and western blot. Osteoblast function was assessed by Alizarin red staining. immunoresponsive gene 1 (Irg1)-deficient mice were used in various inflammatory or non-inflammatory models of bone loss. Tissue gene expression was analysed by RNA in situ hybridisation.

RESULTS

We show that during differentiation preosteoclasts rearrange their tricarboxylic acid cycle, a process crucially depending on both glucose and glutamine. This rearrangement is characterised by the induction of Irg1 and production of itaconate, which accumulates intracellularly and extracellularly. While the IRG1-itaconate axis is dispensable for osteoclast generation in vitro and in vivo, we demonstrate that itaconate stimulates osteoblasts by accelerating osteogenic differentiation in both human and murine cells. This enhanced osteogenic differentiation is accompanied by reduced proliferation and altered metabolism. Additionally, supplementation of itaconate increases bone formation by boosting osteoblast activity in mice. Conversely, Irg1-deficient mice exhibit decreased bone mass and have reduced osteoproliferative lesions in experimental arthritis.

CONCLUSION

In summary, we identify itaconate, generated as a result of the metabolic rewiring during osteoclast differentiation, as a previously unrecognised regulator of osteoblasts.

Androgen signaling restricts glutaminolysis to drive sex-specific Th17 metabolism in allergic airway inflammation

Female individuals have an increased prevalence of many Th17 cell-mediated diseases, including asthma. Androgen signaling decreases Th17 cell-mediated airway inflammation, and Th17 cells rely on glutaminolysis. However, it remains unclear whether androgen receptor (AR) signaling modifies glutamine metabolism to suppress Th17 cell-mediated airway inflammation. We show that Th17 cells from male humans and mice had decreased glutaminolysis compared with female individuals, and that AR signaling attenuated Th17 cell mitochondrial respiration and glutaminolysis in mice. Using allergen-induced airway inflammation mouse models, we determined that females had a selective reliance upon glutaminolysis for Th17-mediated airway inflammation, and that AR signaling attenuated glutamine uptake in CD4+ T cells by reducing expression of glutamine transporters. In patients with asthma, circulating Th17 cells from men had minimal reliance upon glutamine uptake compared to Th17 cells from women. AR signaling thus attenuates glutaminolysis, demonstrating sex-specific metabolic regulation of Th17 cells with implications for Th17 or glutaminolysis targeted therapeutics.

Novel post-translational modifications of protein by metabolites with immune responses and immune-related molecules in cancer immunotherapy

Tumour immunotherapy is an effective and essential treatment for cancer. However, the heterogeneity of tumours and the complex and changeable tumour immune microenvironment (TME) creates many uncertainties in the clinical application of immunotherapy, such as different responses to tumour immunotherapy and significant differences in individual efficacy. It makes anti-tumour immunotherapy face many challenges. Immunometabolism is a critical determinant of immune cell response to specific immune effector molecules, significantly affecting the effects of tumour immunotherapy. It is attributed mainly to the fact that metabolites can regulate the function of immune cells and immune-related molecules through the protein post-translational modifications (PTMs) pathway. This study systematically summarizes a variety of novel protein PTMs including acetylation, propionylation, butyrylation, succinylation, crotonylation, malonylation, glutarylation, 2-hydroxyisobutyrylation, β-hydroxybutyrylation, benzoylation, lactylation and isonicotinylation in the field of tumour immune regulation and immunotherapy. In particular, we elaborate on how different PTMs in the TME can affect the function of immune cells and lead to immune evasion in cancer. Lastly, we highlight the potential treatment with the combined application of target-inhibited protein modification and immune checkpoint inhibitors (ICIs) for improved immunotherapeutic outcomes.

Synovial fluid NMR-based metabolomics in septic and aseptic revision total knee arthroplasty: Implications on diagnosis and treatment

Periprosthetic joint infection (PJI) is one of the most challenging complications following total knee arthroplasty. Despite its importance, there is a paucity of reports in the literature regarding its pathogenesis. Recently, cellular metabolic reprogramming has been shown to play an important role in the progression and outcome of infectious diseases. Therefore, the aim of this study was to evaluate the metabolites composition of the synovial fluid from patients with PJI or aseptic failure of total knee arthroplasties. The synovial fluids from 21 patients scheduled for revision total knee arthroplasty (11 with the diagnosis of PJI and 10 with aseptic failures) were analyzed using 1D 1H NMR spectroscopy. Univariate and multivariate statistical analyzes were used to identify metabolites that were differentially abundant between those groups. A total of 28 metabolites were identified and five of them found to be differentially abundant between infected and non-infected synovial fluids. Lactate, acetate and 3-hydroxybutyrate were found to be in a higher concentration, and glucose and creatine were found reduced in the synovial fluid from PJI patients. Synovial fluid from patients with PJI exhibit a distinct metabolic profile, possibly reflecting metabolic adaptation that occurs in the infected periprosthetic microenvironment. Further research and studies are warranted to gain a broader insight into the metabolic pathways engaged by both pathogen and immune cells in the context of a PJI.

Linking norepinephrine production and performance to diet-induced low-grade, chronic inflammation in the intestine of broilers

Maintenance of intestinal health is critical to successful poultry production and one of the goals of the poultry production industry. For decades the poultry industry has relied upon the inclusion of antibiotic growth promoters (AGP) to achieve this goal and improve growth performance. With the removal of AGPs, the emergence of chronic, low-level gut inflammation has come to the forefront of concern in the poultry industry with the diet being the primary source of inflammatory triggers. We have developed a dietary model of low-grade, chronic intestinal inflammation in broilers that employs feeding a high nonstarch polysaccharides (NSP) diet composed of 30% rice bran to study the effects of this inflammation on bird performance and physiology. For the present studies, we hypothesize that the low-grade chronic inflammation causes neurons in the intestinal enteric nervous system to secrete neurochemicals that activate immune cells that drive the inflammation and negatively affect bird performance. To test our hypothesis, 1-day-old broiler chickens were weighed and divided into 2 dietary regimes: a control corn-soybean diet and a group fed a high NSP diet (30% rice bran). At 7-, 14-, 21-, and 28-d posthatch (PH), birds were weighed, fecal material collected, and 5 birds were sacrificed and sections of duodenal and cecal tissues excised, and duodenal and cecal contents collected for ultra-high performance liquid chromatography analyses (UHPLC). UHPLC revealed 1000s-fold increase in the concentration of norepinephrine (NOR) in birds fed the high NSP diet compared to the control fed birds. Further, the fecal concentrations of NOR were also found to be significantly elevated in the birds on the NSP diet throughout all time points. There were no differences in weight gain nor feed conversion from 1 to 14 d PH, but birds fed the high NSP diet had significantly reduced weight gain and feed conversion from 14 to 28 d PH. The results revealed that a dietary-induced low-grade chronic inflammatory response increased NOR production in the gut which negatively affected bird performance. This study suggests that neuroimmune pathways may serve as a mechanistic target for the development of new interventions to decrease the incidence of chronic inflammation and thereby benefit performance.

Integrated machine learning and bioinformatic analysis of mitochondrial-related signature in chronic rhinosinusitis with nasal polyps

Background

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a prevalent inflammatory disorder affecting the upper respiratory tract. Recent studies have indicated an association between CRSwNP and mitochondrial metabolic disorder characterized by impaired metabolic pathways; however, the precise mechanisms remain unclear. This study aims to investigate the mitochondrial-related signature in individuals diagnosed with CRSwNP.

Methods

Through the integration of differentially expressed genes (DEGs) with the mitochondrial gene set, differentially expressed mitochondrial-related genes (DEMRGs) were identified. Subsequently, the hub DEMRGs were selected using 4 integrated machine learning algorithms. Immune and mitochondrial characteristics were estimated based on CIBERSORT and ssGSEA algorithms. Bioinformatic findings were confirmed through RT-qPCR, immunohistochemistry, and ELISA for nasal tissues, as well as Western blotting analysis for human nasal epithelial cells (hNECs). The relationship between hub DEMRGs and disease severity was assessed using Spearman correlation analysis.

Results

A total of 24 DEMRGs were screened, most of which exhibited lower expression levels in CRSwNP samples. Five hub DEMRGs (ALDH1L1, BCKDHB, CBR3, HMGCS2, and OXR1) were consistently downregulated in both the discovery and validation cohorts. The hub genes showed a high diagnostic performance and were positively correlated with the infiltration of M2 macrophages and resting mast cells. Experimental results confirmed that the 5 genes were downregulated at both the mRNA and protein levels within nasal polyp tissues. Finally, a significant and inverse relationship was identified between the expression levels of these genes and both the Lund-Mackay and Lund-Kennedy scores.

Conclusion

Our findings systematically unraveled 5 hub markers correlated with mitochondrial metabolism and immune cell infiltration in CRSwNP, suggesting their potential to be based to design diagnostic and therapeutic strategies for the disease.

Metabolic mechanisms orchestrated by Sirtuin family to modulate inflammatory responses

Maintaining metabolic homeostasis is crucial for cellular and organismal health throughout their lifespans. The intricate link between metabolism and inflammation through immunometabolism is pivotal in maintaining overall health and disease progression. The multifactorial nature of metabolic and inflammatory processes makes study of the relationship between them challenging. Homologs of Saccharomyces cerevisiae silent information regulator 2 protein, known as Sirtuins (SIRTs), have been demonstrated to promote longevity in various organisms. As nicotinamide adenine dinucleotide-dependent deacetylases, members of the Sirtuin family (SIRT1-7) regulate energy metabolism and inflammation. In this review, we provide an extensive analysis of SIRTs involved in regulating key metabolic pathways, including glucose, lipid, and amino acid metabolism. Furthermore, we systematically describe how the SIRTs influence inflammatory responses by modulating metabolic pathways, as well as inflammatory cells, mediators, and pathways. Current research findings on the preferential roles of different SIRTs in metabolic disorders and inflammation underscore the potential of SIRTs as viable pharmacological and therapeutic targets. Future research should focus on the development of promising compounds that target SIRTs, with the aim of enhancing their anti-inflammatory activity by influencing metabolic pathways within inflammatory cells.

Novel Peripherally Selective Cannabinoid Receptor 1 Neutral Antagonist Improves Metabolic Dysfunction-Associated Steatotic Liver Disease in Mice

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing globally. MASLD is characterized by clinically significant liver steatosis, and a subset of patients progress to more severe metabolic-disorder-associated steatohepatitis (MASH) with liver inflammation and fibrosis. Cannabinoid receptor 1 (CB1) antagonism is a proven therapeutic strategy for the treatment of the phenotypes that underlie MASLD, though work on early centrally penetrant compounds largely ceased following adverse psychiatric indications in humans. We present here preclinical testing of a CB1 neutral antagonist, N-[1-[8-(2-Chlorophenyl)-9-(4-chlorophenyl)-9H-purin-6-yl]-4-phenylpiperidin-4l]methanesulfonamide (RTI-348), with minimal brain exposure when administered to mice. In a diet-induced model of MASLD-induced MASH, administration of RTI-348 decreased the total body and liver weight gain. Animals treated with RTI-348 showed reduced steatosis. Furthermore, they produced lower plasma alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH), biomarkers associated with liver damage. Mice maintained on the MASH diet had elevated expression of genes associated with profibrogenesis, immune response, and extracellular matrix remodeling, and treatment with RTI-348 mitigated these diet-induced changes in gene expression. Using an intracranial electrical self-stimulation model, we also demonstrated that RTI-348 does not produce an anhedonia response, as seen with the first-generation CB1 inverse agonist rimonabant. Altogether, the results herein point to RTI-348 as a promising neutral antagonist for MASH.

Transcriptional Regulation and Function of Malic Enzyme 1 in Human Macrophage Activation

Macrophages represent primary players of the innate immune system. Macrophage activation triggers several signaling pathways and is tightly associated with metabolic changes, which drive different immune subsets. Recent studies unveil the role of various metabolic enzymes in macrophage activation. Here, we show that malic enzyme 1 (ME1) is overexpressed in LPS-induced macrophages. Through chromatin immunoprecipitation, we demonstrate that ME1 transcriptional regulation is under control of NF-κB. Furthermore, ME1 activity is also increased in activated human PBMC-derived macrophages. Notably, ME1 gene silencing decreases nitric oxide as well as reactive oxygen species and prostaglandin E2 inflammatory mediators. Therefore, modulating ME1 provides a potential approach for immunometabolic regulation and in turn macrophage function.