bims-imicid 2023-12-17 papers

bims-imicid

Biomed News

on Immunometabolism of infection, cancer and immune-mediated disease

Issue of 2023–12–17
forty-two papers selected by
Dylan Ryan, University of Cambridge

Lung dendritic-cell metabolism underlies susceptibility to viral infection in diabetes.
Oleic acid availability impacts thymocyte preprogramming and subsequent peripheral Treg cell differentiation.
Itaconate suppresses atherosclerosis by activating a Nrf2-dependent anti-inflammatory response in macrophages in mice.
Itaconate promotes hepatocellular carcinoma progression by epigenetic induction of CD8+ T-cell exhaustion.
Trans-vaccenic Acid Reprograms CD8+ T Cells and Enhances Antitumor Immunity.
Efferocyte-Derived MCTRs Metabolically Prime Macrophages for Continual Efferocytosis via Rac1-Mediated Activation of Glycolysis.
Apolipoprotein E (ApoE) orchestrates adipose tissue inflammation and metabolic disorders through NLRP3 inflammasome.
Lactate-lactylation-HSPA6 axis promotes PRRSV replication by impairing IFN-β production.
Oxidative stress-initiated one-carbon metabolism drives the generation of interleukin-10-producing B cells to resolve pneumonia.
Metabolic plasticity of T cell fate decision.
Serine metabolism in macrophage polarization.
Re-"Formate" T-cell Antitumor Responses.
Combined cerebrospinal fluid metabolomic and cytokine profiling in tuberculosis meningitis reveals robust and prolonged changes in immunometabolic networks.
The role of AMPK in macrophage metabolism, function and polarisation.
Nutrient-sensing growth hormone secretagogue receptor in macrophage programming and meta-inflammation.
AMP-activated protein kinase is necessary for Treg cell functional adaptation to microenvironmental stress.
Fatty acids are crucial to fuel NK cells upon acute retrovirus infection.
Rapid intestinal and systemic metabolic reprogramming in an immunosuppressed environment.
The preprogrammed anti-inflammatory phenotypes of CD11chigh macrophages by Streptococcus pneumoniae aminopeptidase N safeguard from allergic asthma.
[Regulation of Metabolism and the Role of Redox Factors in the Energy Control of Quiescence and Proliferation of Hematopoietic Cells].
Role of solute carrier transporters in regulating dendritic cell maturation and function.
The expanding Pandora's toolbox of CD8+T cell: from transcriptional control to metabolic firing.
Microglial SLC25A28 Deficiency Ameliorates the Brain Injury After Intracerebral Hemorrhage in Mice by Restricting Aerobic Glycolysis.
Role of the co-stimulatory molecule inducible T-cell co-stimulator ligand (ICOSL) in the progression of experimental metabolic dysfunction-associated steatohepatitis.
4-Octyl itaconate alleviates experimental autoimmune prostatitis by inhibiting the NLRP3 inflammasome-induced pyroptosis through activating Nrf2/HO-1 pathway.
4-octyl itaconate ameliorates ventilator-induced lung injury.
4-Octyl itaconate inhibits poly(I:C)-induced interferon-β secretion in mouse bone marrow-derived macrophages partially by activating Nrf2.
Multiomic profiling reveals metabolic alterations mediating aberrant platelet activity and inflammation in myeloproliferative neoplasms.
Platelets of COVID-19 patients display mitochondrial dysfunction, oxidative stress, and energy metabolism failure compatible with cell death.
Gut microbiota-related metabolite alpha-linolenic acid mitigates intestinal inflammation induced by oral infection with Toxoplasma gondii.
In situ lipidomics of Staphylococcus aureus osteomyelitis using imaging mass spectrometry.
The ER stress sensor IRE1 interacts with STIM1 to promote store-operated calcium entry, T cell activation, and muscular differentiation.
Metabolic abnormalities in the bone marrow cells of young offspring born to obese mothers.
Dexmedetomidine post-treatment exacerbates metabolic disturbances in septic cardiomyopathy via α2A-adrenoceptor.
Intracellular K+ Limits T-cell Exhaustion and Preserves Antitumor Function.
Altered Metabolism and DAM-signatures in Female Brains and Microglia with Aging.
Bile acids induce IL-1α and drive NLRP3 inflammasome-independent production of IL-1β in murine dendritic cells.
Metabolomic analysis identifies dysregulation of lipid metabolism in the immune clearance phase of chronic hepatitis B patients.
Metabolic and senescence characteristics associated with the immune microenvironment in ovarian cancer.
Lipopolysaccharide inhibits translation of iron chaperone PCBP1 to regulate inflammatory cytokine response in macrophage.
Quantitative proteomics of tissue infiltrating T cells from CRC patients identified Lipocalin-2 induces T cell apoptosis and promotes tumor cell proliferation by iron efflux.
Single-cell spatial metabolomics with cell-type specific protein profiling for tissue systems biology.

Nature. 2023 Dec 13.

Lung dendritic-cell metabolism underlies susceptibility to viral infection in diabetes.

Samuel Philip Nobs, Aleksandra A Kolodziejczyk, Lital Adler, Nir Horesh, Christine Botscharnikow, Ella Herzog, Gayatree Mohapatra, Sophia Hejndorf, Ryan-James Hodgetts, Igor Spivak, Lena Schorr, Leviel Fluhr, Denise Kviatcovsky, Anish Zacharia, Suzanne Njuki, Dinorah Barasch, Noa Stettner, Mally Dori-Bachash, Alon Harmelin, Alexander Brandis, Tevie Mehlman, Ayelet Erez, Yiming He, Sara Ferrini, Jens Puschhof, Hagit Shapiro, Manfred Kopf, Arieh Moussaieff, Suhaib K Abdeen, Eran Elinav.

People with diabetes feature a life-risking susceptibility to respiratory viral infection, including influenza and SARS-CoV-2 (ref. 1), whose mechanism remains unknown. In acquired and genetic mouse models of diabetes, induced with an acute pulmonary viral infection, we demonstrate that hyperglycaemia leads to impaired costimulatory molecule expression, antigen transport and T cell priming in distinct lung dendritic cell (DC) subsets, driving a defective antiviral adaptive immune response, delayed viral clearance and enhanced mortality. Mechanistically, hyperglycaemia induces an altered metabolic DC circuitry characterized by increased glucose-to-acetyl-CoA shunting and downstream histone acetylation, leading to global chromatin alterations. These, in turn, drive impaired expression of key DC effectors including central antigen presentation-related genes. Either glucose-lowering treatment or pharmacological modulation of histone acetylation rescues DC function and antiviral immunity. Collectively, we highlight a hyperglycaemia-driven metabolic-immune axis orchestrating DC dysfunction during pulmonary viral infection and identify metabolic checkpoints that may be therapeutically exploited in mitigating exacerbated disease in infected diabetics.

DOI: https://doi.org/10.1038/s41586-023-06803-0
Nat Immunol. 2023 Dec 07.

Oleic acid availability impacts thymocyte preprogramming and subsequent peripheral Treg cell differentiation.

Liangyu Lin, Mingyuan Hu, Qing Li, Liming Du, Li Lin, Yueqing Xue, Fanjun Zheng, Fei Wang, Keli Liu, Yu Wang, Jiayin Ye, Xu Jiang, Xuefeng Wang, Jiaqi Wang, Jingjie Zhai, Benming Liu, Hongzhen Xie, Yanqin You, Jinyong Wang, Xiangyin Kong, Dechun Feng, Douglas R Green, Yufang Shi, Ying Wang.

The nature of activation signals is essential in determining T cell subset differentiation; however, the features that determine T cell subset preference acquired during intrathymic development remain elusive. Here we show that naive CD4+ T cells generated in the mouse thymic microenvironment lacking Scd1, encoding the enzyme catalyzing oleic acid (OA) production, exhibit enhanced regulatory T (Treg) cell differentiation and attenuated development of experimental autoimmune encephalomyelitis. Scd1 deletion in K14+ thymic epithelia recapitulated the enhanced Treg cell differentiation phenotype of Scd1-deficient mice. The dearth of OA permitted DOT1L to increase H3K79me2 levels at the Atp2a2 locus of thymocytes at the DN2-DN3 transition stage. Such epigenetic modification persisted in naive CD4+ T cells and facilitated Atp2a2 expression. Upon T cell receptor activation, ATP2A2 enhanced the activity of the calcium-NFAT1-Foxp3 axis to promote naive CD4+ T cells to differentiate into Treg cells. Therefore, OA availability is critical for preprogramming thymocytes with Treg cell differentiation propensities in the periphery.

DOI: https://doi.org/10.1038/s41590-023-01672-1
J Clin Invest. 2023 Dec 12. pii: e173034. [Epub ahead of print]

Itaconate suppresses atherosclerosis by activating a Nrf2-dependent anti-inflammatory response in macrophages in mice.

Jianrui Song, Yanling Zhang, Ryan A Frieler, Anthony Andren, Sherri C Wood, Daniel J Tyrrell, Peter Sajjakulnukit, Jane C Deng, Costas A Lyssiotis, Richard M Mortensen, Morgan Salmon, Daniel R Goldstein.

  Itaconate has emerged as a critical immunoregulatory metabolite. Here, we examined the therapeutic potential of itaconate in atherosclerosis. We found that both itaconate and the enzyme that synthesizes it, aconitate decarboxylase 1 (Acod1, also known as "immune-responsive gene 1"/IRG1) are upregulated during atherogenesis in mice. Deletion of Acod1 in myeloid cells exacerbated inflammation and atherosclerosis in vivo and resulted in an elevated frequency of a specific subset of M1-polarized proinflammatory macrophages in the atherosclerotic aorta. Importantly, Acod1 levels were inversely correlated with clinical occlusion in atherosclerotic human aorta specimens. Treating mice with the itaconate derivative 4-ocytyl itaconate attenuated inflammation and atherosclerosis induced by high cholesterol. Mechanistically, we found that the antioxidant transcription factor, Nuclear factor erythroid-2 Related Factor 2 (Nrf2) was required for itaconate to suppress macrophage activation induced by oxidized lipids in vitro and to decrease atherosclerotic lesion areas in vivo. Overall, our work shows that itaconate suppresses atherogenesis by inducing Nrf2-dependent inhibition of proinflammatory responses in macrophages. Activation of the itaconate pathway may represent an important approach to treat atherosclerosis.

Keywords:  Atherosclerosis; Cardiology; Cardiovascular disease; Inflammation; Macrophages

DOI:  https://doi.org/10.1172/JCI173034
Nat Commun. 2023 Dec 09. 14(1): 8154

Itaconate promotes hepatocellular carcinoma progression by epigenetic induction of CD8+ T-cell exhaustion.

Xuemei Gu, Haoran Wei, Caixia Suo, Shengqi Shen, Chuxu Zhu, Liang Chen, Kai Yan, Zhikun Li, Zhenhua Bian, Pinggen Zhang, Mengqiu Yuan, Yingxuan Yu, Jinzhi Du, Huafeng Zhang, Linchong Sun, Ping Gao.

Itaconate is a well-known immunomodulatory metabolite; however, its role in hepatocellular carcinoma (HCC) remains unclear. Here, we find that macrophage-derived itaconate promotes HCC by epigenetic induction of Eomesodermin (EOMES)-mediated CD8+ T-cell exhaustion. Our results show that the knockout of immune-responsive gene 1 (IRG1), responsible for itaconate production, suppresses HCC progression. Irg1 knockout leads to a decreased proportion of PD-1+ and TIM-3+ CD8+ T cells. Deletion or adoptive transfer of CD8+ T cells shows that IRG1-promoted tumorigenesis depends on CD8+ T-cell exhaustion. Mechanistically, itaconate upregulates PD-1 and TIM-3 expression levels by promoting succinate-dependent H3K4me3 of the Eomes promoter. Finally, ibuprofen is found to inhibit HCC progression by targeting IRG1/itaconate-dependent tumor immunoevasion, and high IRG1 expression in macrophages predicts poor prognosis in HCC patients. Taken together, our results uncover an epigenetic link between itaconate and HCC and suggest that targeting IRG1 or itaconate might be a promising strategy for HCC treatment.

DOI: https://doi.org/10.1038/s41467-023-43988-4
Cancer Discov. 2023 Dec 08. OF1

Trans-vaccenic Acid Reprograms CD8+ T Cells and Enhances Antitumor Immunity.

Trans-vaccenic acid (TVA) enhances antitumor immunity by promoting CD8+ T-cell accumulation and function.

DOI: https://doi.org/10.1158/2159-8290.CD-RW2023-192
Adv Sci (Weinh). 2023 Dec 08. e2304690

Efferocyte-Derived MCTRs Metabolically Prime Macrophages for Continual Efferocytosis via Rac1-Mediated Activation of Glycolysis.

Duco Steven Koenis, Roberta de Matteis, Vinothini Rajeeve, Pedro Cutillas, Jesmond Dalli.

  Clearance of multiple rounds of apoptotic cells (ACs) through continual efferocytosis is critical in the maintenance of organ function, the resolution of acute inflammation, and tissue repair. To date, little is known about the nature of mechanisms and factors that govern this fundamental process. Herein, the authors reported that breakdown of ACs leads to upregulation of 12-lipoxygenase in macrophages. This enzyme converts docosahexaenoic acid to maresin conjugates in tissue regeneration (MCTRs). The levels of these autacoids are elevated at sites of high apoptotic burden in vivo and in efferocytosing macrophages in vitro. Abrogation of MCTR production using genetic approaches limits the ability of macrophages to perform continual efferocytosis both in vivo and in vitro, an effect that is rescued by add-back of MCTRs. Mechanistically, MCTR-mediated priming of macrophages for continual efferocytosis is dependent on alterations in Rac1 signalling and glycolytic metabolism. Inhibition of Rac1 abolishes the ability of MCTRs to increase glucose uptake and efferocytosis in vitro, whereas inhibition of glycolysis limits the MCTR-mediated increases in efferocytosis and tissue repair. Together, these findings demonstrate that upregulation of MCTRs by efferocytosing macrophages plays a central role in the regulation of continual efferocytosis via the autocrine and paracrine modulation of metabolic pathways.

Keywords:  efferocytosis; macrophages; metabolism; specialized pro-resolving mediators (SPM); tissue repair

DOI:  https://doi.org/10.1002/advs.202304690
Mol Biomed. 2023 Dec 08. 4(1): 47

Apolipoprotein E (ApoE) orchestrates adipose tissue inflammation and metabolic disorders through NLRP3 inflammasome.

Yulin Zhang, Ziwei Cheng, Liyu Hong, Jia Liu, Xinyue Ma, Wenjing Wang, Ran Pan, Wenjie Lu, Qichao Luo, Shan Gao, Qin Kong.

  Obesity is a metabolic disorder characterized by the hypertrophy expansion of adipose tissue, resulting in dysregulated energy metabolism, and accompanied by chronic low-grade inflammation. Adipose tissue macrophages (ATMs), a principal component of inflammation, respond to microenvironment signals and modulate adipose tissue remodeling and metabolic processes situation-specific. However, the mechanisms governing how the organism maintains equilibrium between its chronic inflammation and metabolism still need to be understood. Here, we describe a novel role of apolipoprotein E (ApoE), which associated with lipid particles, in maintaining fat deposition and system metabolic inflammation. Using human samples and mouse models, we show that ApoE is robustly downregulated in obese individuals, db/db mice, and mice of high-fat diet (HFD) feeding and increased in obese subjects with diabetes. Furthermore, we found that ApoE deficiency mice globally prevented obesity by restraining adipose tissue expansion and improved systemic glucose tolerance and insulin sensitivity. However, macrophage contributed to metabolic inflammation due to increased IL-1β production in adipose tissue from ApoE-/- mice induced by HFD. Our results suggest that the role of ApoE in regulating obesity and obesity-associated glucose dysregulation is inconsistent. Mechanistically, ApoE modulates of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome priming and activation step. Thus, our studies might provide new sights into ApoE, which is required for obesity-induced hyperglycemia, hyperinsulinism, and adaptive inflammation responses but diminishes the tolerance towards a subsequent metabolic inflammatory challenge. Our study shed new light on the integral role of apolipoprotein APOE in immunometabolism and adipose tissue homeostasis.

Keywords:  Adipose tissue; Apolipoprotein E (ApoE); Macrophage; Metabolic inflammation; NOD-, LRR- and Pyrin Domain-Containing Protein 3 (NLRP3)

DOI:  https://doi.org/10.1186/s43556-023-00158-8
J Virol. 2023 Dec 13. e0167023

Lactate-lactylation-HSPA6 axis promotes PRRSV replication by impairing IFN-β production.

Yu Pang, Yanrong Zhou, Yucheng Wang, Liurong Fang, Shaobo Xiao.

   IMPORTANCE: As a newly identified epigenetic modification, lactate-induced lactylation has received attentions because it plays important roles in gene expression and contributes to tumorigenesis and the innate immune response. Previous studies showed that many viruses upregulate cellular lactate levels; however, whether virus-elevated lactate induces lactylation and the subsequent biological significance of the modification to viral infection have not been reported. In this study, we demonstrated that porcine reproductive and respiratory syndrome virus (PRRSV) infection induced cellular lactylation, which, in turn, upregulated the expression of HSPA6, an IFN-negative regulator. We also dissected the mechanism by which HSPA6 negatively regulates IFN-β production. To our knowledge, this is the first report to study virus-induced lactylation and establish the relationship between lactylation and virus infection.

Keywords:  heat shock 70 kDa protein 6 (HSPA6); interferon; lactate; lactylation; porcine reproductive and respiratory syndrome virus

DOI:  https://doi.org/10.1128/jvi.01670-23
Cell Mol Immunol. 2023 Dec 11.

Oxidative stress-initiated one-carbon metabolism drives the generation of interleukin-10-producing B cells to resolve pneumonia.

Ying Fu, Baichao Yu, Qi Wang, Zhou Lu, Hushan Zhang, Dan Zhang, Feifei Luo, Ronghua Liu, Luman Wang, Yiwei Chu.

  The metabolic reprogramming underlying the generation of regulatory B cells during infectious diseases remains unknown. Using a Pseudomonas aeruginosa-induced pneumonia model, we reported that IL-10-producing B cells (IL-10+ B cells) play a key role in spontaneously resolving infection-mediated inflammation. Accumulated cytosolic reactive oxygen species (ROS) during inflammation were shown to drive IL-10+ B-cell generation by remodeling one-carbon metabolism. Depletion of the enzyme serine hydroxymethyltransferase 1 (Shmt1) led to inadequate one-carbon metabolism and decreased IL-10+ B-cell production. Furthermore, increased one-carbon flux elevated the levels of the methyl donor S-adenosylmethionine (SAM), altering histone H3 lysine 4 methylation (H3K4me) at the Il10 gene to promote chromatin accessibility and upregulate Il10 expression in B cells. Therefore, the one-carbon metabolism-associated compound ethacrynic acid (EA) was screened and found to potentially treat infectious pneumonia by boosting IL-10+ B-cell generation. Overall, these findings reveal that ROS serve as modulators to resolve inflammation by reprogramming one-carbon metabolism pathways in B cells.

Keywords:  H3K4me; IL-10-producing B cell; One-carbon metabolism; Pneumonia; Reactive oxygen species

DOI:  https://doi.org/10.1038/s41423-023-01109-7
Chin Med J (Engl). 2023 Dec 12.

Metabolic plasticity of T cell fate decision.

Xiaoli Pan, Jiajia Wang, Lianjun Zhang, Guideng Li, Bo Huang.

ABSTRACT: The efficacy of adaptive immune responses in cancer treatment relies heavily on the state of the T cells. Upon antigen exposure, T cells undergo metabolic reprogramming, leading to the development of functional effectors or memory populations. However, within the tumor microenvironment (TME), metabolic stress impairs CD8+ T cell anti-tumor immunity, resulting in exhausted differentiation. Recent studies suggest that targeting T cell metabolism could offer promising therapeutic opportunities to enhance T cell immunotherapy. In this review, we provide a comprehensive summary of the intrinsic and extrinsic factors necessary for metabolic reprogramming during the development of effector and memory T cells in response to acute and chronic inflammatory conditions. Furthermore, we delved into the different metabolic switches that occur during T cell exhaustion, exploring how prolonged metabolic stress within the TME triggers alterations in cellular metabolism and the epigenetic landscape that contribute to T cell exhaustion, ultimately leading to a persistently exhausted state. Understanding the intricate relationship between T cell metabolism and cancer immunotherapy can lead to the development of novel approaches to improve the efficacy of T cell-based treatments against cancer.

DOI: https://doi.org/10.1097/CM9.0000000000002989
Inflamm Res. 2023 Dec 09.

Serine metabolism in macrophage polarization.

Xinqiong Huang, Xue Yang, Li Xiang, Yuping Chen.

   OBJECTIVE: Emerging studies have revealed that macrophages possess different dependences on the uptake, synthesis, and metabolism of serine for their activation and functionalization, necessitating our insight into how serine availability and utilization impact macrophage activation and inflammatory responses.
METHODS: This article summarizes the reports published domestically and internationally about the serine uptake, synthesis, and metabolic flux by the macrophages polarizing with distinct stimuli and under different pathologic conditions, and particularly analyzes how altered serine metabolism rewires the metabolic behaviors of polarizing macrophages and their genetic and epigenetic reprogramming.
RESULTS: Macrophages dynamically change serine metabolism to orchestrate their anabolism, redox balance, mitochondrial function, epigenetics, and post-translation modification, and thus match the distinct needs for both classical and alternative activation.
CONCLUSION: Serine metabolism coordinates multiple metabolic pathways to tailor macrophage polarization and their responses to different pathogenic attacks and thus holds the potential as therapeutic target for types of acute and chronic inflammatory diseases.

Keywords:  Inflammation; Innate immunity; Macrophage polarization; Serine metabolism

DOI:  https://doi.org/10.1007/s00011-023-01815-y
Cancer Discov. 2023 Dec 12. 13(12): 2507-2509

Re-"Formate" T-cell Antitumor Responses.

Mei-Chun Lin, Sofie Hedlund Moller, Ping-Chih Ho.

SUMMARY: Rowe and colleagues discover that one-carbon (1C) metabolism rewiring occurs upon T-cell activation to support proliferation and cytolytic activity in CD8+ T cells and that supplementation of 1C donor formate rescues the dysfunctional T cells and their responsiveness to anti-PD-1 in selective tumor-infiltrated T-cell subsets. This finding represents an attractive strategy to overcome a metabolic vulnerability in the tumor microenvironment and improve the efficacy of immune checkpoint blockade. See related article by Rowe et al., p. 2566 (8).

DOI: https://doi.org/10.1158/2159-8290.CD-23-1059
Tuberculosis (Edinb). 2023 Dec 02. pii: S1472-9792(23)00185-3. [Epub ahead of print]144 102462

Combined cerebrospinal fluid metabolomic and cytokine profiling in tuberculosis meningitis reveals robust and prolonged changes in immunometabolic networks.

Jeffrey Tomalka, Ashish Sharma, Alison G C Smith, Teona Avaliani, Mariam Gujabidze, Tinatin Bakuradze, Shorena Sabanadze, Dean P Jones, Zaza Avaliani, Maia Kipiani, Russell R Kempker, Jeffrey M Collins.

  Much of the high mortality in tuberculosis meningitis (TBM) is attributable to excessive inflammation, making it imperative to identify targets for host-directed therapies that reduce pathologic inflammation and mortality. In this study, we investigate how cytokines and metabolites in the cerebral spinal fluid (CSF) associate with TBM at diagnosis and during TBM treatment. At diagnosis, TBM patients (n = 17) demonstrate significant increases of cytokines and chemokines that promote inflammation and cell migration including IL-17A, IL-2, TNFα, IFNγ, and IL-1β versus asymptomatic controls without known central nervous system pathology (n = 20). Inflammatory immune signaling had a strong positive correlation with immunomodulatory metabolites including kynurenine, lactic acid, and carnitine and strong negative correlations with tryptophan and itaconate. Inflammatory immunometabolic networks were only partially reversed with two months of effective TBM treatment and remained significantly different compared to CSF from controls. Together, these data highlight a critical role for host metabolism in regulating the inflammatory response to TBM and indicate the timeline for restoration of immune homeostasis in the CSF is prolonged.

Keywords:  CSF; Cytokines; Meningitis; Metabolomics; Tuberculosis

DOI:  https://doi.org/10.1016/j.tube.2023.102462
J Transl Med. 2023 Dec 08. 21(1): 892

The role of AMPK in macrophage metabolism, function and polarisation.

Yinxing Cui, Junhua Chen, Zhao Zhang, Houyin Shi, Weichao Sun, Qian Yi.

  AMP-activated protein kinase (AMPK) is a ubiquitous sensor of energy and nutritional status in eukaryotic cells. It plays a key role in regulating cellular energy homeostasis and multiple aspects of cell metabolism. During macrophage polarisation, AMPK not only guides the metabolic programming of macrophages, but also counter-regulates the inflammatory function of macrophages and promotes their polarisation toward the anti-inflammatory phenotype. AMPK is located at the intersection of macrophage metabolism and inflammation. The metabolic characteristics of macrophages are closely related to immune-related diseases, infectious diseases, cancer progression and immunotherapy. This review discusses the structure of AMPK and its role in the metabolism, function and polarisation of macrophages. In addition, it summarises the important role of the AMPK pathway and AMPK activators in the development of macrophage-related diseases.

Keywords:  AMPK; Macrophage; Macrophage-related diseases; Metabolism; Polarisation

DOI:  https://doi.org/10.1186/s12967-023-04772-6
Mol Metab. 2023 Dec 11. pii: S2212-8778(23)00186-2. [Epub ahead of print] 101852

Nutrient-sensing growth hormone secretagogue receptor in macrophage programming and meta-inflammation.

Da Mi Kim, Jong Han Lee, Quan Pan, Hye Won Han, Zheng Shen, Sahar Eshghjoo, Chia-Shan Wu, Wanbao Yang, Ji Yeon Noh, David W Threadgill, Shaodong Guo, Gus Wright, Robert Alaniz, Yuxiang Sun.

   OBJECTIVE: Obesity-associated chronic inflammation, aka meta-inflammation, is a key pathogenic driver for obesity-associated comorbidity. Growth hormone secretagogue receptor (GHSR) is known to mediate the effects of nutrient-sensing hormone ghrelin in food intake and fat deposition. We previously reported that global GHSR ablation protects against diet-induced inflammation and insulin resistance, but the site(s) of action and mechanism are unknown. Macrophages are key drivers of meta-inflammation. To unravel the role of GHSR in macrophages, we generated myeloid-specific Ghsr knockout mice (LysM-Cre;Ghsrf/f).
METHODS: LysM-Cre;Ghsrf/f and control Ghsrf/f mice were subjected to 5 months of high-fat diet (HFD) feeding to induce obesity. In vivo, metabolic profiling of food intake, physical activity, and energy expenditure, as well as glucose and insulin tolerance tests (GTT and ITT) were performed. At termination, peritoneal macrophages (PMs), epididymal white adipose tissue (eWAT), and liver were analyzed by flow cytometry and histology. For ex vivo studies, bone marrow-derived macrophages (BMDMs) were generated from the mice and treated with palmitic acid (PA) or lipopolysaccharide (LPS). For in vitro studies, macrophage RAW264.7 cells with Ghsr overexpression or Insulin receptor substrate 2 (Irs2) knockdown were studied.
RESULTS: We found that Ghsr expression in peritoneal macrophages was increased under HFD feeding. In vivo, HFD-fed LysM-Cre;Ghsrf/f mice exhibited significantly attenuated systemic inflammation and insulin resistance. Tissue analysis showed that HFD-fed LysM-Cre;Ghsrf/f mice have significantly decreased monocyte/macrophage infiltration, inflammatory activation, and lipid accumulation in eWAT and liver. Ex vivo, Ghsr-deficient macrophages protected against PA- or LPS-induced pro-inflammatory polarization, showing reduced glycolysis and increased fatty acid oxidation. At molecular level, GHSR metabolically programs macrophage polarization through PKA-CREB-IRS2-AKT2 signaling pathway.
CONCLUSIONS: These novel results demonstrate that macrophage GHSR plays a key role in pathogenesis of meta-inflammation, and macrophage GHSR promotes macrophage infiltration and induces pro-inflammatory polarization. These exciting findings suggest that GHSR may serve as a novel immunotherapeutic target for the treatment of obesity and its associated comorbidity.

Keywords:  GHSR; Macrophage; insulin resistance; macrophage polarization; meta-inflammation; obesity

DOI:  https://doi.org/10.1016/j.molmet.2023.101852
bioRxiv. 2023 Dec 01. pii: 2023.11.29.568904. [Epub ahead of print]

AMP-activated protein kinase is necessary for Treg cell functional adaptation to microenvironmental stress.

Manuel A Torres Acosta, Nurbek Mambetsariev, Carla P Reyes Flores, Kathryn A Helmin, Qianli Liu, Anthony M Joudi, Luisa Morales-Nebreda, Jonathan Gurkan, Kathleen Cheng, Hiam Abdala-Valencia, Samuel E Weinberg, Benjamin D Singer.

CD4+FOXP3+ regulatory T (Treg) cells maintain self-tolerance, suppress the immune response to cancer, and protect against tissue injury in the lung and other organs. Treg cells require mitochondrial metabolism to exert their function, but how Treg cells adapt their metabolic programs to sustain and optimize their function during an immune response occurring in a metabolically stressed microenvironment remains unclear. Here, we tested whether Treg cells require the energy homeostasis-maintaining enzyme AMP-activated protein kinase (AMPK) to adapt to metabolically aberrant microenvironments caused by malignancy or lung injury, finding that AMPK is dispensable for Treg cell immune-homeostatic function but is necessary for full Treg cell function in B16 melanoma tumors and during acute lung injury caused by influenza virus pneumonia. AMPK-deficient Treg cells had lower mitochondrial mass and exhibited an impaired ability to maximize aerobic respiration. Mechanistically, we found that AMPK regulates DNA methyltransferase 1 to promote transcriptional programs associated with mitochondrial function in the tumor microenvironment. In the lung during viral pneumonia, we found that AMPK sustains metabolic homeostasis and mitochondrial activity. Induction of DNA hypomethylation was sufficient to rescue mitochondrial mass in AMPK-deficient Treg cells, linking DNA methylation with AMPK function and mitochondrial metabolism. These results define AMPK as a determinant of Treg cell adaptation to metabolic stress and offer potential therapeutic targets in cancer and tissue injury.

DOI: https://doi.org/10.1101/2023.11.29.568904
Front Immunol. 2023 ;14 1296355

Fatty acids are crucial to fuel NK cells upon acute retrovirus infection.

Simone Schimmer, Daniela Mittermüller, Tanja Werner, Paul E Görs, Sven W Meckelmann, David K Finlay, Ulf Dittmer, Elisabeth Littwitz-Salomon.

  Natural killer (NK) cells are cytotoxic innate immune cells, able to recognize and eliminate virus-infected as well as cancer cells. Metabolic reprogramming is crucial for their activity as they have enhanced energy and nutritional demands for their functions during an infection. Fatty acids (FAs) represent an important source of cellular energy and are essential for proliferation of immune cells. However, the precise role of FAs for NK cells activity in retrovirus infection was unknown. Here we show that activated NK cells increase the expression of the FA uptake receptor CD36 and subsequently the uptake of FAs upon acute virus infection. We found an enhanced flexibility of NK cells to utilize FAs as source of energy compare to naïve NK cells. NK cells that were able to generate energy from FAs showed an augmented target cell killing and increased expression of cytotoxic parameters. However, NK cells that were unable to generate energy from FAs exhibited a severely decreased migratory capacity. Our results demonstrate that NK cells require FAs in order to fight acute virus infection. Susceptibility to severe virus infections as it is shown for people with malnutrition may be augmented by defects in the FA processing machinery, which might be a target to therapeutically boost NK cell functions in the future.

Keywords:  CD36; NK cells; beta-oxidation; cytotoxicity; fatty acids; lipid metabolism; migration; retrovirus

DOI:  https://doi.org/10.3389/fimmu.2023.1296355
BMC Microbiol. 2023 Dec 09. 23(1): 394

Rapid intestinal and systemic metabolic reprogramming in an immunosuppressed environment.

Bing Ma, Samuel J Gavzy, Michael France, Yang Song, Hnin Wai Lwin, Allison Kensiski, Vikas Saxena, Wenji Piao, Ram Lakhan, Jegan Iyyathurai, Lushen Li, Christina Paluskievicz, Long Wu, Marina WillsonShirkey, Emmanuel F Mongodin, Valeria R Mas, Jonathan S Bromberg.

  Intrinsic metabolism shapes the immune environment associated with immune suppression and tolerance in settings such as organ transplantation and cancer. However, little is known about the metabolic activities in an immunosuppressive environment. In this study, we employed metagenomic, metabolomic, and immunological approaches to profile the early effects of the immunosuppressant drug tacrolimus, antibiotics, or both in gut lumen and circulation using a murine model. Tacrolimus induced rapid and profound alterations in metabolic activities within two days of treatment, prior to alterations in gut microbiota composition and structure. The metabolic profile and gut microbiome after seven days of treatment was distinct from that after two days of treatment, indicating continuous drug effects on both gut microbial ecosystem and host metabolism. The most affected taxonomic groups are Clostriales and Verrucomicrobiae (i.e., Akkermansia muciniphila), and the most affected metabolic pathways included a group of interconnected amino acids, bile acid conjugation, glucose homeostasis, and energy production. Highly correlated metabolic changes were observed between lumen and serum metabolism, supporting their significant interactions. Despite a small sample size, this study explored the largely uncharacterized microbial and metabolic events in an immunosuppressed environment and demonstrated that early changes in metabolic activities can have significant implications that may serve as antecedent biomarkers of immune activation or quiescence. To understand the intricate relationships among gut microbiome, metabolic activities, and immune cells in an immune suppressed environment is a prerequisite for developing strategies to monitor and optimize alloimmune responses that determine transplant outcomes.

Keywords:  Antibiotics; Gut dysbiosis; Gut microbiome; Immune tolerance; Immunosuppression; Integrative multi-omics; Metabolome; Transplantation

DOI:  https://doi.org/10.1186/s12866-023-03141-z
J Transl Med. 2023 Dec 11. 21(1): 898

The preprogrammed anti-inflammatory phenotypes of CD11chigh macrophages by Streptococcus pneumoniae aminopeptidase N safeguard from allergic asthma.

Shifei Yao, Danlin Weng, Yan Wang, Yanyu Zhang, Qi Huang, Kaifeng Wu, Honghui Li, Xuemei Zhang, Yibing Yin, Wenchun Xu.

   BACKGROUND: Early microbial exposure is associate with protective allergic asthma. We have previously demonstrated that Streptococcus pneumoniae aminopeptidase N (PepN), one of the pneumococcal components, inhibits ovalbumin (OVA) -induced airway inflammation in murine models of allergic asthma, but the underlying mechanism was incompletely determined.
METHODS: BALB/c mice were pretreated with the PepN protein and exposed intranasally to HDM allergen. The anti-inflammatory mechanisms were investigated using depletion and adoptive transfer experiments as well as transcriptome analysis and isolated lung CD11chigh macrophages.
RESULTS: We found pretreatment of mice with PepN promoted the proliferation of lung-resident F4/80+CD11chigh macrophages in situ but also mobilized bone marrow monocytes to infiltrate lung tissue that were then transformed into CD11high macrophages. PepN pre-programmed the macrophages during maturation to an anti-inflammatory phenotype by shaping the metabolic preference for oxidative phosphorylation (OXPHOS) and also inhibited the inflammatory response of macrophages by activating AMP-activated protein kinase. Furthermore, PepN treated macrophages also exhibited high-level costimulatory signaling molecules which directed the differentiation into Treg.
CONCLUSION: Our results demonstrated that the expansion of CD11chigh macrophages in lungs and the OXPHOS metabolic bias of macrophages are associated with reduced allergic airway inflammation after PepN exposure, which paves the way for its application in preventing allergic asthma.

Keywords:  Allergic asthma; Hygiene hypothesis; Macrophage; Oxidation phosphorylation; Streptococcus pneumoniae aminopeptidase N

DOI:  https://doi.org/10.1186/s12967-023-04768-2
Mol Biol (Mosk). 2023 Nov-Dec;57(6):57(6): 1175-1187

[Regulation of Metabolism and the Role of Redox Factors in the Energy Control of Quiescence and Proliferation of Hematopoietic Cells].

M V Kalashnikova, N S Polyakova, A V Belyavsky.

  One of the key regulators of hematopoietic stem cell (HSC) maintenance is cellular metabolism. Resting HSCs use anaerobic glycolysis as the main source of energy. During expansion and differentiation under conditions of steady state hematopoiesis, the energy needs of activated HSCs increase by many fold. To meet the increased demands, cells switch to mitochondrial oxidative phosphorylation, which is accompanied by an increase in reactive oxygen species (ROS) production. Here, the molecular mechanisms maintaining glycolysis in HSCs, as well as the factors determining the increase in metabolic activity and the transition to mitochondrial biogenesis during HSC activation are discussed. We focus on the role of HIF (hypoxia-inducible factor) proteins as key mediators of the cellular response to hypoxia, and also consider the phenomenon of extraphysiological oxygen shock (EPHOSS), leading to the forced differentiation of HSCs as well as methods of overcoming it. Finally, the role of fatty acid oxidation (FAO) in hematopoiesis is discussed. Understanding the metabolic needs of normal HSCs and precursors is crucial for the development of new treatments for diseases related to the hematopoietic and immune systems.

Keywords:  HIF; anaerobic glycolysis; fatty acid oxidation; hematopoiesis; hematopoietic stem cells; mitochondrial biogenesis; oxidative stress; reactive oxygen species; redox factors; stress hematopoiesis

DOI:  https://doi.org/10.31857/S0026898423060095, EDN: REJDYZ
Eur J Immunol. 2023 Dec 11. e2350385

Role of solute carrier transporters in regulating dendritic cell maturation and function.

Lin Shao, Mengxin Yang, Tao Sun, Haotang Xia, Dan Du, Xun Li, Zuliang Jie.

  Dendritic cells (DCs) are specialized antigen-presenting cells (APCs) that initiate and regulate innate and adaptive immune responses. Solute carrier (SLC) transporters mediate diverse physiological functions and maintain cellular metabolite homeostasis. Recent studies have highlighted the significance of SLCs in immune processes. Notably, upon activation, immune cells undergo rapid and robust metabolic reprogramming, largely dependent on SLCs to modulate diverse immunological responses. In this review, we explore the central roles of SLC proteins and their transported substrates in shaping DC functions. We provide a comprehensive overview of recent studies on amino acid transporters, metal ion transporters, and glucose transporters, emphasizing their essential contributions to DC homeostasis under varying pathological conditions. Finally, we propose potential strategies for targeting SLCs in DCs to bolster immunotherapy for a spectrum of human diseases. This article is protected by copyright. All rights reserved.

Keywords:  Dendritic cells; Immune regulation; Immunotherapy; Solute carrier transporters

DOI:  https://doi.org/10.1002/eji.202350385
J Transl Med. 2023 Dec 11. 21(1): 905

The expanding Pandora's toolbox of CD8+T cell: from transcriptional control to metabolic firing.

Jinghong Wu, Zhendong Lu, Hong Zhao, Mingjun Lu, Qing Gao, Nanying Che, Jinghui Wang, Teng Ma.

  CD8+ T cells are the executor in adaptive immune response, especially in anti-tumor immunity. They are the subset immune cells that are of high plasticity and multifunction. Their development, differentiation, activation and metabolism are delicately regulated by multiple factors. Stimuli from the internal and external environment could remodel CD8+ T cells, and correspondingly they will also make adjustments to the microenvironmental changes. Here we describe the most updated progresses in CD8+ T biology from transcriptional regulation to metabolism mechanisms, and also their interactions with the microenvironment, especially in cancer and immunotherapy. The expanding landscape of CD8+ T cell biology and discovery of potential targets to regulate CD8+ T cells will provide new viewpoints for clinical immunotherapy.

Keywords:  Anti-tumor immunity; CD8+ T cells; Immunotherapy

DOI:  https://doi.org/10.1186/s12967-023-04775-3
Inflammation. 2023 Dec 12.

Microglial SLC25A28 Deficiency Ameliorates the Brain Injury After Intracerebral Hemorrhage in Mice by Restricting Aerobic Glycolysis.

Ruili Han, Lei Liu, Yuying Wang, Ruolin Wu, Ying Yang, Yuanlin Zhao, Lele Jian, Yuan Yuan, Lijun Zhang, Yu Gu, Changjun Gao, Jing Ye.

  The microglia overactivation-induced neuroinflammation is a significant cause of the brain injury after intracerebral hemorrhage (ICH). Iron homeostasis is crucial for microglia activation, but the mechanism and causality still need further study. This study aimed to explore the roles and mechanism of the mitochondrial iron transporter SLC25A28 in microglia activation after ICH. Intrastriatal injection of autologous blood was used to establish ICH model, and the neuroinflammation, iron metabolism and brain injuries were assessed in wildtype or microglia-specific SLC25A28 knockout mice after ICH. Mitochondria iron levels and microglial function were determined in SLC25A28 overexpressed or deleted microglia. The extracellular acidification rate (ECAR), lactate production, and glycolytic enzyme levels were used to determine aerobic glycolysis. The results showed that ICH stimulated mitochondrial iron overload, and synchronously upregulated the SLC25A28 expression. In vitro, SLC25A28 overexpression increased mitochondrial iron levels in microglia. Interestingly, microglial SLC25A28 deficiency ameliorated neuroinflammation, brain edema, blood-brain barrier injury and ethological alterations in mice after ICH. Mechanically, SLC25A28 deficiency inhibited microglial activation by restricting the aerobic glycolysis. Moreover, zinc protoporphyrin could reduce SLC25A28 expression and mitigated brain injury. SLC25A28 plays crucial roles in mitochondrial iron homeostasis and microglia activation after ICH, and it might be a potential therapeutic target for ICH.

Keywords:  SLC25A28; intracerebral hemorrhage; iron; microglia; mitochondria

DOI:  https://doi.org/10.1007/s10753-023-01931-1
Front Immunol. 2023 ;14 1290391

Role of the co-stimulatory molecule inducible T-cell co-stimulator ligand (ICOSL) in the progression of experimental metabolic dysfunction-associated steatohepatitis.

Alessia Provera, Naresh Naik Ramavath, Laila Lavanya Gadipudi, Casimiro Luca Gigliotti, Elena Boggio, Cristina Vecchio, Ian Stoppa, Roberta Rolla, Renzo Boldorini, Mario Pirisi, Carlo Smirne, Emanuele Albano, Umberto Dianzani, Salvatore Sutti.

   Background and aims: Inducible T-cell Co-Stimulator (ICOS) present on T-lymphocytes and its ligand ICOSL expressed by myeloid cells play multiple roles in regulating T-cell functions. However, recent evidence indicates that reverse signalling involving ICOSL is also important in directing the differentiation of monocyte-derived cells. In this study, we investigated the involvement of ICOS/ICOSL dyad in modulating macrophage functions during the evolution of metabolic dysfunction-associated steatohepatitis (MASH).
Results: In animal models of MASH, ICOS was selectively up-regulated on CD8+ T-cells in parallel with an expansion of ICOSL-expressing macrophages. An increase in circulating soluble ICOSL was also evident in patients with MASH as compared to healthy individuals. ICOSL knockout (ICOSL-/-) mice receiving choline/methionine deficient (MCD) diet for 6 weeks had milder steatohepatitis than wild type mice. MASH improvement was confirmed in mice fed with cholesterol-enriched Western diet for 24 weeks in which ICOSL deficiency greatly reduced liver fibrosis along with the formation of crown-like macrophage aggregates producing the pro-fibrogenic mediators osteopontin (OPN) and galectin-3 (Gal-3). These effects associated with a selective shewing of F4-80+/CD11bhigh monocyte-derived macrophages (MoMFs) expressing the Triggering Receptor Expressed on Myeloid cells 2 (TREM2) to CD11blow/F4-80+ cells positive for the Kupffer cell marker C-type lectin-like type 2 receptor (CLEC-2), thus indicating an increased MoMF maturation toward monocyte-derived Kupffer cells.
Conclusions: These results suggest that CD8+ T-cells interaction with monocyte-derived macrophages through ICOS/ICOSL critically supports a specific subset of TREM2+-expressing cells contributing to the evolution of steatohepatitis. The data also point ICOS/ICOSL dyad as a possible target for therapeutic interventions in MASH.

Keywords:  chronic inflammation; galectin-3; liver fibrosis; macrophages; metabolic dysfunction-associated steatotic liver disease; nonalcoholic fatty liver disease; osteopontin

DOI:  https://doi.org/10.3389/fimmu.2023.1290391
Prostate. 2023 Dec 10.

4-Octyl itaconate alleviates experimental autoimmune prostatitis by inhibiting the NLRP3 inflammasome-induced pyroptosis through activating Nrf2/HO-1 pathway.

Xiaohu Zhao, Rui Feng, Juan Chen, Qing Jiang, Xiaoliang Hua, Chaozhao Liang.

   BACKGROUND: Chronic prostatitis demonstrates a prevalence rate of nearly 5%-10% among young and middle-aged individuals, significantly affecting their daily lives. Researchers have obtained significant outcomes investigating the anti-inflammatory properties of itaconic acid (IA) and its derivative, 4-Octyl itaconate (4-OI), against diverse chronic inflammatory disorders, such as osteoarthritis and airway inflammation. Nevertheless, whether IA can also exert anti-inflammatory effects in chronic prostatitis requires extensive research and validation.
METHODS: Human prostate tissues obtained through transurethral prostate resection (TURP) from individuals were divided into three groups based on different levels of inflammation using hematoxylin and eosin staining (H&E). Subsequently, immunohistochemistry (IHC) was employed to detect the expression of immune-responsive gene 1 (IRG-1) in these different groups. The animal experiment of this study induced experimental autoimmune prostatitis (EAP) in nonobese diabetic mice through intradermal prostate antigen injection and complete Freund's adjuvant. Then, the experimental group received intraperitoneal injections of different doses of 4-OI, while the control group received injections of saline. Western blot (WB), H&E staining, and TUNEL staining helped analyze the prostate tissues, while enzyme-linked immunosorbent assay (ELISA) helped evaluate serum inflammatory factors. Reactive oxygen species, superoxide dismutase (SOD), and malondialdehyde (MDA) were assessed for oxidative stress across experimental groups.
RESULTS: IHC analysis of human prostate tissue depicts that IRG-1 expression enhances as prostate inflammation worsens, highlighting the critical role of IA in human prostatitis. The application of 4-OI increased Nrf2/HO-1 expression while inhibited NLRP3 expression following the WB results, and its application resulted in a decrease in cell pyroptosis in prostate tissue, demonstrated by the results of TUNEL staining. Administering a Nrf2 inhibitor ML385 1 h before intraperitoneal injection of 50 mg/kg 4-OI reversed the previous conclusion, further confirming the above conclusion from another perspective. Meanwhile, the ELISA results of serum inflammatory factors (IL-1β, IL-6, and TNF-α), as well as the measurements of oxidative stress markers MDA and SOD, further confirmed the specific anti-inflammatory effects of 4-OI in EAP.
CONCLUSIONS: The present study indicates that 4-OI can alleviates EAP by inhibiting the NLRP3 inflammasome-induced pyroptosis through activating Nrf2/HO-1 pathway, which may facilitate a novel approach toward prostatitis treatment.

Keywords:  4-Octyl itaconate; chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS); inflammation; pyroptosis

DOI:  https://doi.org/10.1002/pros.24652
Arch Biochem Biophys. 2023 Dec 10. pii: S0003-9861(23)00352-1. [Epub ahead of print] 109853

4-octyl itaconate ameliorates ventilator-induced lung injury.

Xiudan Wang, Weijing Kong, Rui Yang, Chunyan Yang.

  Ventilator-induced lung injury (VILI) disturbs the disordered immune system and causes persistent inflammatory damage. 4-octyl itaconate (OI) is a synthetic cell-permeable itaconate derivative with antioxidant and anti-inflammatory effects. In this study, we assessed whether OI protects against VILI. OI was intraperitoneally injected for three days before mechanical ventilation (MV; 20 ml/kg at 70 breaths/min) for 2 h. Mouse lung vascular endothelial cells (MLVECs) were pretreated with OI (62.5, 125, and 250 μM) prior to cyclic stretch for 4 h. We found that OI attenuated VILI and inflammatory response. OI also increased superoxide dismutase, nuclear factor E2-related factor 2, and heme oxygenase-1 levels, and decreased reactive oxygen species and malondialdehyde levels. Furthermore, OI inhibited the expression of NLR family pyrin domain-containing 3 (NLRP3), caspase-1 p20, apoptosis-associated speck-like protein containing a CARD, and N-terminal fragment of gasdermin D. Therefore, OI attenuates VILI, potentially by suppressing oxidative stress and NLRP3 activation.

Keywords:  4-octyl itaconate; NLRP3; Oxidative stress; Ventilator-induced lung injury

DOI:  https://doi.org/10.1016/j.abb.2023.109853
Heliyon. 2023 Dec;9(12): e23001

4-Octyl itaconate inhibits poly(I:C)-induced interferon-β secretion in mouse bone marrow-derived macrophages partially by activating Nrf2.

Ying-Xing Yue, Bing-Bing Jia, Ji-Rong Wang, Ying-Zheng Weng, Gen-Xiang Mao, Yan Lu, Jing Yan, Zhou-Xin Yang.

  Viruses have become a major threat to human health. Interferon-β (IFN-β) has a key role in the antivirus process, as it can increase the expression of antivirus-associated genes. Itaconate and its derivatives can regulate the immune response, secretion of inflammatory factors, and pyroptosis of macrophages. The effect of itaconate on IFN-β secretion of double-stranded RNA-induced macrophages are not well known. A derivative of itaconate, 4-octoyl itaconate (4-OI), was used to treat mouse bone marrow-derived macrophages (BMDM) induced with 100 μg/mL poly(I:C). The IFN-β concentration was detected through ELISA, and IFN-β mRNA expression was detected through quantitative PCR. High-throughput transcriptome sequencing was used to analyze changes in the BMDM transcriptome after 4-OI treatment. The Nrf2 expression was knocked down with siRNA.4-OI inhibited poly(I:C)-induced IFN-β secretion and mRNA expression in BMDM. Results of transcriptome sequencing revealed that 4-OI downregulated 1047 genes and upregulated 822 genes. GO and KEGG enrichment of differently expressed genes revealed that many downregulated genes were related to the anti-virus process, whereas many upregulated genes were related to metabolism. The Nrf2 inhibitor ML385 and Nrf2 siRNA could partially reverse the inhibitory effect of 4-OI. In conclusion, 4-octyl itaconate could inhibit the poly(I:C)-induced interferon-β secretion in BMDM partially by regulating Nrf2.

Keywords:  4-Octoyl itaconate; Interferon-β; Macrophages; Nrf2

DOI:  https://doi.org/10.1016/j.heliyon.2023.e23001
J Clin Invest. 2023 Dec 07. pii: e172256. [Epub ahead of print]

Multiomic profiling reveals metabolic alterations mediating aberrant platelet activity and inflammation in myeloproliferative neoplasms.

Fan He, Angelo B A Laranjeira, Tim Kong, Shuyang Lin, Katrina J Ashworth, Alice Liu, Nina M Lasky, Daniel Ac Fisher, Maggie J Cox, Mary C Fulbright, Lilian A Antunes Heck, LaYow C Yu, Molly Brakhane, Bei Gao, Stephen M Sykes, Angelo D'Alessandro, Jorge A Di Paola, Stephen T Oh.

  Platelets from patients with myeloproliferative neoplasms (MPNs) exhibit a hyperreactive phenotype. Here, we found elevated P-selectin exposure and platelet-leukocyte aggregates indicating activation of platelets from essential thrombocythemia (ET) patients. Single cell RNA-seq analysis of primary samples revealed significant enrichment of transcripts related to platelet activation, mTOR and oxidative phosphorylation (OXPHOS) in ET patient platelets. These observations were validated via proteomic profiling. Platelet metabolomics revealed distinct metabolic phenotypes consisting of elevated ATP generation, accompanied by increases in the levels of multiple intermediates of the tricarboxylic acid (TCA) cycle, but lower alpha-ketoglutarate (α-KG) in MPN patients. Inhibition of PI3K/AKT/mTOR signaling significantly reduced metabolic responses and hyperreactivity in MPN patient platelets, while α-KG supplementation markedly reduced oxygen consumption and ATP generation. Ex vivo incubation of platelets from both MPN patients and Jak2 V617F mice with α-KG significantly reduced platelet activation responses. Oral α-KG supplementation of Jak2 V617F mice decreased splenomegaly and reduced hematocrit, monocyte and platelet counts. Finally, α-KG incubation significantly decreased proinflammatory cytokine secretion from MPN CD14+ monocytes. Our results reveal a previously unrecognized metabolic disorder in conjunction with aberrant PI3K/AKT/mTOR signaling, contributing to platelet hyperreactivity in MPN patients.

Keywords:  Hematology; Platelets

DOI:  https://doi.org/10.1172/JCI172256
Res Pract Thromb Haemost. 2023 Oct;7(7): 102213

Platelets of COVID-19 patients display mitochondrial dysfunction, oxidative stress, and energy metabolism failure compatible with cell death.

Amsterdam University Medical Center COVID-19 Biobank Study Groupd.vandebeek@amsterdamumc.nl

   Background: Alterations in platelet function have been implicated in the pathophysiology of COVID-19 since the beginning of the pandemic. While early reports linked hyperactivated platelets to thromboembolic events in COVID-19, subsequent investigations demonstrated hyporeactive platelets with a procoagulant phenotype. Mitochondria are important for energy metabolism and the function of platelets.
Objectives: Here, we sought to map the energy metabolism of platelets in a cohort of noncritically ill COVID-19 patients and assess platelet mitochondrial function, activation status, and responsiveness to external stimuli.
Methods: We enrolled hospitalized COVID-19 patients and controls between October 2020 and December 2021. Platelets function and metabolism was analyzed by flow cytometry, metabolomics, glucose fluxomics, electron and fluorescence microscopy and western blot.
Results: Platelets from COVID-19 patients showed increased phosphatidylserine externalization indicating a procoagulant phenotype and hyporeactivity to ex vivo stimuli, associated with profound mitochondrial dysfunction characterized by mitochondrial depolarization, lower mitochondrial DNA-encoded transcript levels, an altered mitochondrial morphology consistent with increased mitochondrial fission, and increased pyruvate/lactate ratios in platelet supernatants. Metabolic profiling by untargeted metabolomics revealed NADH, NAD+, and ATP among the top decreased metabolites in patients' platelets, suggestive of energy metabolism failure. Consistently, platelet fluxomics analyses showed a strongly reduced utilization of 13C-glucose in all major energy pathways together with a rerouting of glucose to de novo generation of purine metabolites. Patients' platelets further showed evidence of oxidative stress, together with increased glutathione oxidation and synthesis. Addition of plasma from COVID-19 patients to normal platelets partially reproduced the phenotype of patients' platelets and disclosed a temporal relationship between mitochondrial decay and (subsequent) phosphatidylserine exposure and hyporeactivity.
Conclusion: These data link energy metabolism failure in platelets from COVID-19 patients with a prothrombotic platelet phenotype with features matching cell death.

Keywords:  COVID-19; blood platelets; cell death; energy metabolism; mitochondria; oxidative stress

DOI:  https://doi.org/10.1016/j.rpth.2023.102213
Microbiome. 2023 Dec 12. 11(1): 273

Gut microbiota-related metabolite alpha-linolenic acid mitigates intestinal inflammation induced by oral infection with Toxoplasma gondii.

Jing Yang, Songhao Liu, Qian Zhao, Xiaobing Li, Kangfeng Jiang.

   BACKGROUND: Oral infection with cysts is the main transmission route of Toxoplasma gondii (T. gondii), which leads to lethal intestinal inflammation. It has been widely recognized that T. gondii infection alters the composition and metabolism of the gut microbiota, thereby affecting the progression of toxoplasmosis. However, the potential mechanisms remain unclear. In our previous study, there was a decrease in the severity of toxoplasmosis after T. gondii α-amylase (α-AMY) was knocked out. Here, we established mouse models of ME49 and Δα-amy cyst infection and then took advantage of 16S rRNA gene sequencing and metabolomics analysis to identify specific gut microbiota-related metabolites that mitigate T. gondii-induced intestinal inflammation and analyzed the underlying mechanism.
RESULTS: There were significant differences in the intestinal inflammation between ME49 cyst- and Δα-amy cyst-infected mice, and transferring feces from mice infected with Δα-amy cysts into antibiotic-treated mice mitigated colitis caused by T. gondii infection. 16S rRNA gene sequencing showed that the relative abundances of gut bacteria, such as Lactobacillus and Bacteroides, Bifidobacterium, [Prevotella], Paraprevotella and Macellibacteroides, were enriched in mice challenged with Δα-amy cysts. Spearman correlation analysis between gut microbiota and metabolites indicated that some fatty acids, including azelaic acid, suberic acid, alpha-linolenic acid (ALA), and citramalic acid, were highly positively correlated with the identified bacterial genera. Both oral administration of ALA and fecal microbiota transplantation (FMT) decreased the expression of pro-inflammatory cytokines and restrained the MyD88/NF-κB pathway, which mitigated colitis and ultimately improved host survival. Furthermore, transferring feces from mice treated with ALA reshaped the colonization of beneficial bacteria, such as Enterobacteriaceae, Proteobacteria, Shigella, Lactobacillus, and Enterococcus.
CONCLUSIONS: The present findings demonstrate that the host gut microbiota is closely associated with the severity of T. gondii infection. We provide the first evidence that ALA can alleviate T. gondii-induced colitis by improving the dysregulation of the host gut microbiota and suppressing the production of pro-inflammatory cytokines via the MyD88/NF-κB pathway. Our study provides new insight into the medical application of ALA for the treatment of lethal intestinal inflammation caused by Toxoplasma infection. Video Abstract.

Keywords:  Alpha-linolenic acid; Fecal microbiota transplantation; Gut microbiota; Intestinal inflammation; Metabolite; Toxoplasma gondii

DOI:  https://doi.org/10.1186/s40168-023-01681-0
bioRxiv. 2023 Dec 02. pii: 2023.12.01.569690. [Epub ahead of print]

In situ lipidomics of Staphylococcus aureus osteomyelitis using imaging mass spectrometry.

Christopher J Good, Casey E Butrico, Madeline E Colley, Katherine N Gibson-Corley, James E Cassat, Jeffrey M Spraggins, Richard M Caprioli.

Osteomyelitis occurs when Staphylococcus aureus invades the bone microenvironment, resulting in a bone marrow abscess with a spatially defined architecture of cells and biomolecules. Imaging mass spectrometry and microscopy are invaluable tools that can be employed to interrogate the lipidome of S. aureus -infected murine femurs to reveal metabolic and signaling consequences of infection. Here, nearly 250 lipids were spatially mapped to healthy and infection-associated morphological features throughout the femur, establishing composition profiles for tissue types. Ether lipids and arachidonoyl lipids were significantly altered between cells and tissue structures in abscesses, suggesting their roles in abscess formation and inflammatory signaling. Sterols, triglycerides, bis(monoacylglycero)phosphates, and gangliosides possessed ring-like distributions throughout the abscess, indicating dysregulated lipid metabolism in a subpopulation of leukocytes that cannot be discerned with traditional microscopy. These data provide chemical insight into the signaling function and metabolism of cells in the fibrotic border of abscesses, likely characteristic of lipid-laden macrophages.

DOI: https://doi.org/10.1101/2023.12.01.569690
Cell Rep. 2023 Dec 05. pii: S2211-1247(23)01552-8. [Epub ahead of print]42(12): 113540

The ER stress sensor IRE1 interacts with STIM1 to promote store-operated calcium entry, T cell activation, and muscular differentiation.

Amado Carreras-Sureda, Xin Zhang, Loann Laubry, Jessica Brunetti, Stéphane Koenig, Xiaoxia Wang, Cyril Castelbou, Claudio Hetz, Yong Liu, Maud Frieden, Nicolas Demaurex.

  Store-operated Ca2+ entry (SOCE) mediated by stromal interacting molecule (STIM)-gated ORAI channels at endoplasmic reticulum (ER) and plasma membrane (PM) contact sites maintains adequate levels of Ca2+ within the ER lumen during Ca2+ signaling. Disruption of ER Ca2+ homeostasis activates the unfolded protein response (UPR) to restore proteostasis. Here, we report that the UPR transducer inositol-requiring enzyme 1 (IRE1) interacts with STIM1, promotes ER-PM contact sites, and enhances SOCE. IRE1 deficiency reduces T cell activation and human myoblast differentiation. In turn, STIM1 deficiency reduces IRE1 signaling after store depletion. Using a CaMPARI2-based Ca2+ genome-wide screen, we identify CAMKG2 and slc105a as SOCE enhancers during ER stress. Our findings unveil a direct crosstalk between SOCE and UPR via IRE1, acting as key regulator of ER Ca2+ and proteostasis in T cells and muscles. Under ER stress, this IRE1-STIM1 axis boosts SOCE to preserve immune cell functions, a pathway that could be targeted for cancer immunotherapy.

Keywords:  CP: Cell biology; CP: Immunology; CRISPR screening; CaMPARI; ER stress; IRE1; SOCE; STIM1; T cells; calcium; muscle

DOI:  https://doi.org/10.1016/j.celrep.2023.113540
bioRxiv. 2023 Dec 01. pii: 2023.11.29.569274. [Epub ahead of print]

Metabolic abnormalities in the bone marrow cells of young offspring born to obese mothers.

Elysse Phillips, Yem Alharithi, Leena Kadam, Lisa M Coussens, Sushil Kumar, Alina Maloyan.

Intrauterine metabolic reprogramming occurs in obese mothers during gestation, putting the offspring at high risk of developing obesity and associated metabolic disorders even before birth. We have generated a mouse model of maternal high-fat diet-induced obesity that recapitulates the metabolic changes seen in humans. Here, we profiled and compared the metabolic characteristics of bone marrow cells of newly weaned 3-week-old offspring of dams fed either a high-fat (Off-HFD) or a regular diet (Off-RD). We utilized a state-of-the-art targeted metabolomics approach coupled with a Seahorse metabolic analyzer. We revealed significant metabolic perturbation in the offspring of HFD-fed vs. RD-fed dams, including utilization of glucose primarily via oxidative phosphorylation, and reduction in levels of amino acids, a phenomenon previously linked to aging. Furthermore, in the bone marrow of three-week-old offspring of high-fat diet-fed mothers, we identified a unique B cell population expressing CD19 and CD11b, and found increased expression of Cyclooxygenase-2 (COX-2) on myeloid CD11b, and on CD11b hi B cells, with all the populations being significantly more abundant in offspring of dams fed HFD but not a regular diet. Altogether, we demonstrate that the offspring of obese mothers show metabolic and immune changes in the bone marrow at a very young age and prior to any symptomatic metabolic disease.

DOI: https://doi.org/10.1101/2023.11.29.569274
Biomed Pharmacother. 2023 Dec 12. pii: S0753-3322(23)01791-2. [Epub ahead of print]170 115993

Dexmedetomidine post-treatment exacerbates metabolic disturbances in septic cardiomyopathy via α2A-adrenoceptor.

Yaqian Xu, Xue Zhang, Xiangxu Tang, Chanjuan Zhang, Jason G Cahoon, Yingwei Wang, Hongmei Li, Xiuxiu Lv, Yiyang Wang, Zhi Wang, Huadong Wang, Duomeng Yang.

  Cardiomyopathy is a common complication and significantly increases the risk of death in septic patients. Our previous study demonstrated that post-treatment with dexmedetomidine (DEX) aggravates septic cardiomyopathy. However, the mechanisms for the side effect of DEX post-treatment on septic cardiomyopathy are not well-defined. Here we employed a cecal ligation and puncture (CLP) model and α2A-adrenoceptor deficient (Adra2a-/-) mice to observe the effects of DEX post-treatment on myocardial metabolic disturbances in sepsis. CLP mice displayed significant cardiac dysfunction, altered mitochondrial dynamics, reduced cardiac lipid and glucose uptake, impaired fatty acid and glucose oxidation, enhanced glycolysis and decreased ATP production in the myocardium, almost all of which were dramatically enhanced by DEX post-treatment in septic mice. In Adra2a-/- mice, DEX post-treatment did not affect cardiac dysfunction and metabolic disruptions in CLP-induced sepsis. Additionally, Adra2a-/- mice exhibited impaired cardiac function, damaged myocardial mitochondrial structures, and disturbed fatty acid metabolism and glucose oxidation. In sum, DEX post-treatment exacerbates metabolic disturbances in septic cardiomyopathy in a α2A-adrenoceptor dependent manner.

Keywords:  Dexmedetomidine; Energy metabolism; Mitochondrial damage; Sepsis-induced myocardial dysfunction; α(2A)-adrenoceptor

DOI:  https://doi.org/10.1016/j.biopha.2023.115993
Cancer Immunol Res. 2023 Dec 08. OF1-OF12

Intracellular K+ Limits T-cell Exhaustion and Preserves Antitumor Function.

Camille Collier, Kelly Wucherer, Matthew McWhorter, Chelsea Jenkins, Alexandra Bartlett, Rahul Roychoudhuri, Robert Eil.

T cells are often compromised within cancers, allowing disease progression. We previously found that intratumoral elevations in extracellular K+, related to ongoing cell death, constrained CD8+ T-cell Akt-mTOR signaling and effector function. To alleviate K+-mediated T-cell dysfunction, we pursued genetic means to lower intracellular K+. CD8+ T cells robustly and dynamically express the Na+/K+ ATPase, among other K+ transporters. CRISPR-Cas9-mediated disruption of the Atp1a1 locus lowered intracellular K+ and elevated the resting membrane potential (i.e., Vm, Ψ). Despite compromised Ca2+ influx, Atp1a1-deficient T cells harbored tonic hyperactivity in multiple signal transduction cascades, along with a phenotype of exhaustion in mouse and human CD8+ T cells. Provision of exogenous K+ restored intracellular levels in Atp1a1-deficient T cells and prevented damaging levels of reactive oxygen species (ROS), and both antioxidant treatment and exogenous K+ prevented Atp1a1-deficient T-cell exhaustion in vitro. T cells lacking Atp1a1 had compromised persistence and antitumor activity in a syngeneic model of orthotopic murine melanoma. Translational application of these findings will require balancing the beneficial aspects of intracellular K+ with the ROS-dependent nature of T-cell effector function. See related Spotlight by Banuelos and Borges da Silva.

DOI: https://doi.org/10.1158/2326-6066.CIR-23-0319
bioRxiv. 2023 Nov 30. pii: 2023.11.28.569104. [Epub ahead of print]

Altered Metabolism and DAM-signatures in Female Brains and Microglia with Aging.

Nicholas R W Cleland, Garrett J Potter, Courtney Buck, Daphne Quang, Dean Oldham, Mikaela Neal, Anthony Saviola, Christy S Niemeyer, Evgenia Dobrinskikh, Kimberley D Bruce.

Despite Alzheimer's disease (AD) disproportionately affecting women, the mechanisms remain elusive. In AD, microglia undergo 'metabolic reprogramming', which contributes to microglial dysfunction and AD pathology. However, how sex and age contribute to metabolic reprogramming in microglia is understudied. Here, we use metabolic imaging, transcriptomics, and metabolic assays to probe age-and sex-associated changes in brain and microglial metabolism. Glycolytic and oxidative metabolism in the whole brain was determined using Fluorescence Lifetime Imaging Microscopy (FLIM). Young female brains appeared less glycolytic than male brains, but with aging, the female brain became 'male-like.' Transcriptomic analysis revealed increased expression of disease-associated microglia (DAM) genes (e.g., ApoE , Trem2 , LPL ), and genes involved in glycolysis and oxidative metabolism in microglia from aged females compared to males. To determine whether estrogen can alter the expression of these genes, BV-2 microglia-like cell lines, which abundantly express DAM genes, were supplemented with 17β-estradiol (E2). E2 supplementation resulted in reduced expression of DAM genes, reduced lipid and cholesterol transport, and substrate-dependent changes in glycolysis and oxidative metabolism. Consistent with the notion that E2 may suppress DAM-associated factors, LPL activity was elevated in the brains of aged female mice. Similarly, DAM gene and protein expression was higher in monocyte-derived microglia-like (MDMi) cells derived from middle-aged females compared to age-matched males and was responsive to E2 supplementation. FLIM analysis of MDMi from young and middle-aged females revealed reduced oxidative metabolism and FAD+ with age. Overall, our findings show that altered metabolism defines age-associated changes in female microglia and suggest that estrogen may inhibit the expression and activity of DAM-associated factors, which may contribute to increased AD risk, especially in post-menopausal women.

DOI: https://doi.org/10.1101/2023.11.28.569104
Front Immunol. 2023 ;14 1285357

Bile acids induce IL-1α and drive NLRP3 inflammasome-independent production of IL-1β in murine dendritic cells.

Ewa Oleszycka, Eoin C O'Brien, Michael Freeley, Ed C Lavelle, Aideen Long.

  Bile acids are amphipathic molecules that are synthesized from cholesterol in the liver and facilitate intestinal absorption of lipids and nutrients. They are released into the small intestine upon ingestion of a meal where intestinal bacteria can modify primary into secondary bile acids. Bile acids are cytotoxic at high concentrations and have been associated with inflammatory diseases such as liver inflammation and Barrett's Oesophagus. Although bile acids induce pro-inflammatory signalling, their role in inducing innate immune cytokines and inflammation has not been fully explored to date. Here we demonstrate that the bile acids, deoxycholic acid (DCA) and chenodeoxycholic acid (CDCA) induce IL-1α and IL-1β secretion in vitro in primed bone marrow derived dendritic cells (BMDCs). The secretion of IL-1β was found not to require expression of NLRP3, ASC or caspase-1 activity; we can't rule out all inflammasomes. Furthermore, DCA and CDCA were shown to induce the recruitment of neutrophils and monocytes to the site of injection an intraperitoneal model of inflammation. This study further underlines a mechanistic role for bile acids in the pathogenesis of inflammatory diseases through stimulating the production of pro-inflammatory cytokines and recruitment of innate immune cells.

Keywords:  IL-1α; IL-1β; bile acids; dendritic cells; inflammation

DOI:  https://doi.org/10.3389/fimmu.2023.1285357
J Pharm Biomed Anal. 2023 Dec 03. pii: S0731-7085(23)00669-6. [Epub ahead of print]239 115900

Metabolomic analysis identifies dysregulation of lipid metabolism in the immune clearance phase of chronic hepatitis B patients.

Xiangyang Ye, Xiongzhi He, Zhenting Hu, Fengfeng Zheng, Xiaogang Huang, Xuemei Xie, Feihua Chen, Hanbing Ou, Rongxian Qiu.

  There is an accelerated progression of liver necroinflammation and fibrosis in the liver during the immune clearance (IC) phase of Chronic hepatitis B virus (HBV) infection, which are critical indicators of antiviral treatment for chronic hepatitis B (CHB) infection. This study applied serum metabolomics to identify the potential metabolite biomarkers for differential diagnosis between the CHB immune tolerance (IT) and Immune clearance (IC) phases. A liquid chromatography-mass spectrometry (LC-MS)-based approach was applied to evaluate and compared the serum metabolic profiles of 28 patients in IT phase and 33 patients in IC phase and appropriate statistical methods with MetaboAnalystR 2.0 R package to analyze those metabolites. The differential metabolites between IT and TC groups were classified and the top altered classification were lipids and lipid-like molecules and fatty acyls, clearly indicating that there were differences in the lipid metabolomic profile of HBV-infected patients with IT vs. IR phase. We identified the top 10 potential metabolite biomarkers for differential diagnosis between IT and IR. There were four lipid metabolites among them and the AUC of two of them, octadecadienoyl-sn-glycero-3-phosphocholine and 3-Cycloheptene-l-acetic acid, were 0.983 and 0.933. octadecadienoyl-sn-glycero-3-phosphocholine is Diacylglycerol (18:2n6/18:0) and 3-Cycloheptene-l-acetic acid is hydroxy fatty acids, both of which were associated with lipid metabolism. This study not only provides the potential metabolic biomarkers but also insight into the mechanism of CHB progression during IT clearance phase.

Keywords:  Chronic hepatitis B; Lipid metabolism. immune clearance phase; Metabolite biomarkers; Metabolomics

DOI:  https://doi.org/10.1016/j.jpba.2023.115900
Front Endocrinol (Lausanne). 2023 ;14 1265525

Metabolic and senescence characteristics associated with the immune microenvironment in ovarian cancer.

Jian Xiong, Yiyuan Fu, Jiezheng Huang, Yibin Wang, Xiaolong Jin, Xiaoyan Wan, Liu Huang, Zheng Huang.

  Ovarian cancer is a highly malignant gynecological cancer influenced by the immune microenvironment, metabolic reprogramming, and cellular senescence. This review provides a comprehensive overview of these characteristics. Metabolic reprogramming affects immune cell function and tumor growth signals. Cellular senescence in immune and tumor cells impacts anti-tumor responses and therapy resistance. Targeting immune cell metabolism and inducing tumor cell senescence offer potential therapeutic strategies. However, challenges remain in identifying specific targets and biomarkers. Understanding the interplay of these characteristics can lead to innovative therapeutic approaches. Further research is needed to elucidate mechanisms, validate strategies, and improve patient outcomes in ovarian cancer.

Keywords:  immune microenvironment; metabolism; ovarian cancer; senescence; therapeutic strategies

DOI:  https://doi.org/10.3389/fendo.2023.1265525
Cytokine. 2023 Dec 06. pii: S1043-4666(23)00334-4. [Epub ahead of print]174 156456

Lipopolysaccharide inhibits translation of iron chaperone PCBP1 to regulate inflammatory cytokine response in macrophage.

Sameeksha Yadav, Neeraj K Saini, Diksha Kulshreshtha, Chinmay K Mukhopadhyay.

  Macrophages play a key role in maintaining systemic iron homeostasis and immunity. During pro-inflammatory stage macrophages retain iron due to the decrease of the unique iron exporter ferroportin. Increased cellular iron is sequestered in to storage protein ferritin by iron chaperone poly(rC)-binding protein 1 (PCBP1). However, the fate of PCBP1 and its interaction with ferritin in pro-inflammatory macrophages has not been studied so far. Here we report that PCBP1 protein level is down-regulated in lipopolysaccharide (LPS) treated macrophages. LPS did not alter PCBP1 mRNA and protein stability suggesting inhibition of translation as a mechanism of PCBP1 down-regulation that was confirmed by 35S-methionine incorporation assay. PCBP1 interacts with ferritin-H (Ft-H) subunit to load iron into ferritin. We detected a decreased interaction between PCBP1 and Ft-H after LPS-stimulation. As a result iron loading in to ferritin was affected with simultaneous increase in labile iron pool (LIP). Pre-treatment of cells with iron chelator dampened LPS-induced expression of TNF-α, IL-1β and IL-6 mRNA. Silencing of PCBP1 increased the magnitude of expression of these cytokines compared to control siRNA transfected LPS-treated macrophages. In contrast, overexpression of PCBP1 resulted a decrease in expression of these cytokines compared to vector transfected macrophages. Our results reveal a novel regulation of PCBP1 and its role in expression of cytokines in LPS-induced pro-inflammatory macrophages.

Keywords:  Cytokine; Gene regulation; Iron; Lipopolysaccharide; Macrophage; PCBP1

DOI:  https://doi.org/10.1016/j.cyto.2023.156456
Mol Cell Proteomics. 2023 Dec 08. pii: S1535-9476(23)00202-5. [Epub ahead of print] 100691

Quantitative proteomics of tissue infiltrating T cells from CRC patients identified Lipocalin-2 induces T cell apoptosis and promotes tumor cell proliferation by iron efflux.

Rui Che, Qingsong Wang, Minzhe Li, Jian Shen, Jianguo Ji.

  T cells play the most pivotal roles in anti-tumor immunity, the T cell proteome and the differentially expressed proteins (DEPs) in the tumor immune microenvironment have rarely been identified directly from the clinical samples, especially for tumors that lack effective immunotherapy targets, such as colorectal cancer (CRC). In this study, we analyzed the protein expression pattern of the infiltrating T cells isolated from CRC patients using quantitative proteomics. CD4+ and CD8+ T cells were isolated from clinical samples and labeled by TMT reagents, and the DEPs were quantified by mass spectrometry. The T cell proteome profiling revealed dysfunctions in these tumor-infiltrating T cells. Specifically, anti-tumor immunity was suppressed due to differentially expressed metal ion transporters and immunity regulators. For the first time, Lipocalin-2 (LCN2) was shown to be significantly up-regulated in CD4+ T cells. Quantitative proteomic analysis of LCN2-overexpressed Jurkat cells showed that LCN2 damaged T cells by changes in iron transport. LCN2 induced T cell apoptosis by reducing cellular iron concentration; moreover, the iron that was transported to the tumor microenvironment aided tumor cell proliferation, promoting tumor development. Meanwhile, LCN2 also influenced tumor progression through immune cytokines and cholesterol metabolism. Our results demonstrated that LCN2 has immunosuppressive functions that can promote tumor development; therefore, it is a potential immunotherapy target for CRC.

Keywords:  anti-tumor immunity; colorectal cancer; iron transport; lipocalin-2; tumor-infiltrating T cells

DOI:  https://doi.org/10.1016/j.mcpro.2023.100691
Nat Commun. 2023 Dec 13. 14(1): 8260

Single-cell spatial metabolomics with cell-type specific protein profiling for tissue systems biology.

Thomas Hu, Mayar Allam, Shuangyi Cai, Walter Henderson, Brian Yueh, Aybuke Garipcan, Anton V Ievlev, Maryam Afkarian, Semir Beyaz, Ahmet F Coskun.

Metabolic reprogramming in cancer and immune cells occurs to support their increasing energy needs in biological tissues. Here we propose Single Cell Spatially resolved Metabolic (scSpaMet) framework for joint protein-metabolite profiling of single immune and cancer cells in male human tissues by incorporating untargeted spatial metabolomics and targeted multiplexed protein imaging in a single pipeline. We utilized the scSpaMet to profile cell types and spatial metabolomic maps of 19507, 31156, and 8215 single cells in human lung cancer, tonsil, and endometrium tissues, respectively. The scSpaMet analysis revealed cell type-dependent metabolite profiles and local metabolite competition of neighboring single cells in human tissues. Deep learning-based joint embedding revealed unique metabolite states within cell types. Trajectory inference showed metabolic patterns along cell differentiation paths. Here we show scSpaMet's ability to quantify and visualize the cell-type specific and spatially resolved metabolic-protein mapping as an emerging tool for systems-level understanding of tissue biology.

DOI: https://doi.org/10.1038/s41467-023-43917-5