bims-mepmim Biomed News
on Metabolites in pathological microenvironments and immunometabolism
Issue of 2022–05–08
forty-nine papers selected by
Erika Mariana Palmieri, NIH/NCI Laboratory of Cancer ImmunoMetabolism
  1. Metabolic reprogramming by ex vivo glutamine inhibition endows CAR-T cells with less-differentiated phenotype and persistent antitumor activity.
  2. An integrated toolbox to profile macrophage immunometabolism.
  3. Coping with starvation: Cysteine keeps mTORC1 suppressed to ensure survival.
  4. Regulation of Nucleotide Metabolism with Nutrient-Sensing Nanodrugs for Cancer Therapy.
  5. A FAsT contribution: Adipocytes rewire their metabolism to acquire immune functions.
  6. Hyperpolarized [5-13C,4,4-2H2,5-15N]-L-glutamine provides a means of annotating in vivo metabolic utilization of glutamine.
  7. Optimized protocol for stable isotope tracing and steady-state metabolomics in mouse HER2+ breast cancer brain metastasis.
  8. Glutaminase inhibition impairs CD8 T cell activation in STK11-/Lkb1-deficient lung cancer.
  9. Dual Inhibitions on Glucose/Glutamine Metabolisms for Nontoxic Pancreatic Cancer Therapy.
  10. The deacetylase SIRT2 contributes to autoimmune disease pathogenesis by modulating IL-17A and IL-2 transcription.
  11. The Give-and-Take Interaction Between the Tumor Microenvironment and Immune Cells Regulating Tumor Progression and Repression.
  12. Glycolytic and lipid oxidative metabolic programs are essential for freshly-isolated regulatory T cells in mice with sepsis.
  13. Tumor-infiltrating T-regulatory cells adapt to altered metabolism to promote tumor-immune escape.
  14. Glycine decarboxylase maintains mitochondrial protein lipoylation to support tumor growth.
  15. Combinatorial GxGxE CRISPR screen identifies SLC25A39 in mitochondrial glutathione transport linking iron homeostasis to OXPHOS.
  16. Lipid exposure activates gene expression changes associated with estrogen receptor negative breast cancer.
  17. Letting go of damaged mitochondria.
  18. Intracellular infection and immune system cues rewire adipocytes to acquire immune function.
  19. IP3R-mediated Ca2+ signaling controls B cell proliferation through metabolic reprogramming.
  20. Rheumatoid arthritis T cell and muscle oxidative metabolism associate with exercise-induced changes in cardiorespiratory fitness.
  21. Cyclooxygenase-2 in adipose tissue macrophages limits adipose tissue dysfunction in obese mice.
  22. IFNγ Regulates NAD+ Metabolism to Promote the Respiratory Burst in Human Monocytes.
  23. Trans-omics analysis of insulin action reveals a cell growth subnetwork which co-regulates anabolic processes.
  24. Targeting BCAT1 combined with α-ketoglutarate triggers metabolic synthetic lethality in glioblastoma.
  25. Simultaneous glutamine metabolism and PD-L1 inhibition to enhance suppression of triple-negative breast cancer.
  26. The Adipose Tissue Macrophages Central to Adaptive Thermoregulation.
  27. Mimicking Tumor Microenvironment by 3D Bioprinting: 3D Cancer Modeling.
  28. The Interplay Between Inflammation and Stromal Components in Pancreatic Cancer.
  29. Krebs takes a turn at cell differentiation.
  30. OxLDL induces membrane structure rearrangement leading to biomechanics alteration and migration deficiency in macrophage.
  31. Noncoding RNA-mediated macrophage and cancer cell crosstalk in hepatocellular carcinoma.
  32. Dynamic O-GlcNAcylation coordinates ferritinophagy and mitophagy to activate ferroptosis.
  33. Molecular mechanism of crosstalk between immune and metabolic systems in metabolic syndrome.
  34. Endothelial Prohibitin Mediates Bi-directional Long Chain Fatty Acid Transport in White and Brown Adipose Tissues.
  35. Deep-lipidotyping by mass spectrometry: recent technical advances and applications.
  36. Single-cell N6-methyladenosine regulator patterns guide intercellular communication of tumor microenvironment that contribute to colorectal cancer progression and immunotherapy.
  37. Pleural Resident Macrophages and Pleural IRA B Cells Promote Efficient Immunity Against Pneumonia by Inducing Early Pleural Space Inflammation.
  38. Splenic Dendritic Cells and Macrophages Drive B Cells to Adopt a Plasmablast Cell Fate.
  39. Oxidized high-density lipoprotein promotes CD36 palmitoylation and increases lipid uptake in macrophages.
  40. Metabolic regulation of (-)-epicatechin and the colonic metabolite 2,3-dihydroxybenzoic acid on the glucose uptake, lipid accumulation and insulin signalling in cardiac H9c2 cells.
  41. Mechanism of Erastin-Induced Ferroptosis in MDA-MB-231 Human Breast Cancer Cells: Evidence for a Critical Role of Protein Disulfide Isomerase.
  42. Iron accumulation induces oxidative stress, while depressing inflammatory polarization in human iPSC-derived microglia.
  43. Lactate Transporter SLC16A3 (MCT4) as an Onco-Immunological Biomarker Associating Tumor Microenvironment and Immune Responses in Lung Cancer.
  44. Microbiota-mediated skewing of tryptophan catabolism modulates CD4+ T cells in lupus-prone mice.
  45. The functional role of OGDH for maintaining mitochondrial respiration and identity of primed human embryonic stem cells.
  46. ROS-responsive liposomes as an inhaled drug delivery nanoplatform for idiopathic pulmonary fibrosis treatment via Nrf2 signaling.
  47. Carnosine synthase deficiency in mice affects protein metabolism in skeletal muscle.
  48. SM22α-lineage niche cells regulate intramembranous bone regeneration via PDGFRβ-triggered hydrogen sulfide production.
  49. Acidic Microenvironments Found in Cutaneous Leishmania Lesions Curtail NO-Dependent Antiparasitic Macrophage Activity.
  1. Cancer Lett. 2022 Apr 28. pii: S0304-3835(22)00194-X. [Epub ahead of print]538 215710
    Metabolic reprogramming by ex vivo glutamine inhibition endows CAR-T cells with less-differentiated phenotype and persistent antitumor activity.
    Luyan Shen, Yefei Xiao, Chaoting Zhang, Shance Li, Xia Teng, Likun Cui, Ting Liu, Nan Wu, Zheming Lu.
      The inadequate in vivo persistence of chimeric antigen receptor (CAR)-modified T cells has been shown to lead to poor therapeutic efficacy and disease recurrence. In vivo persistence is associated with the differentiation subsets infused, with less differentiated TN or TCM conferring superior renewal capacity and antitumor immunity compared to TEM or TEFF. However, ex vivo expanded CAR-T cells exhibit phenotypic heterogeneity with majority of TEM or TEFF subsets and very low populations of TN and TCM. The transition of differentiation subsets is closely correlated with T cell metabolism fitness. Effector T cell differentiation from TN or TCM requires glutamine uptake and metabolism. Using a CD19-specific CAR, we demonstrated that glutamine inhibition by adding the glutamine antagonist 6-Diazo-5-oxo-l-norleucine (DON) into the culture endows CAR-T cells with enhanced mitochondrial OXPHOS utilizing fatty acids and reduced glycolytic activity, and retains more TN or TCM subsets. DON- pretreated CAR-T cells exhibited stronger cytotoxic lysis in vitro and more robust elimination of tumor burdens in vivo. This study suggests that glutamine inhibition ex vivo would be a potential approach for modulating metabolism and differentiation state to improve the efficacy of CAR-T cell therapy.
    Keywords:  Fatty acid oxidation; Glutamine antagonist; Glycolysis; Memory T cell; Mitochondrial OXPHOS
    DOI:  https://doi.org/10.1016/j.canlet.2022.215710
  2. Cell Rep Methods. 2022 Apr 25. 2(4): 100192
    An integrated toolbox to profile macrophage immunometabolism.
    Sanne G S Verberk, Kyra E de Goede, Friederike S Gorki, Xanthe A M H van Dierendonck, Rafael J Argüello, Jan Van den Bossche.
      Macrophages are dynamic immune cells that can adopt several activation states. Fundamental to these functional activation states is the regulation of cellular metabolic processes. Especially in mice, metabolic alterations underlying pro-inflammatory or homeostatic phenotypes have been assessed using various techniques. However, researchers new to the field may encounter ambiguity in choosing which combination of techniques is best suited to profile immunometabolism. To address this need, we have developed a toolbox to assess cellular metabolism in a semi-high-throughput 96-well-plate-based format. Application of the toolbox to activated mouse and human macrophages enables fast metabolic pre-screening and robust measurement of extracellular fluxes, mitochondrial mass and membrane potential, and glucose and lipid uptake. Moreover, we propose an application of SCENITH technology for ex vivo metabolic profiling. We validate established activation-induced metabolic rewiring in mouse macrophages and report new insights into human macrophage metabolism. By thoroughly discussing each technique, we hope to guide readers with practical workflows for investigating immunometabolism.
    Keywords:  immunometabolism; macrophages; metabolism; semi-high throughput screening; toolbox
    DOI:  https://doi.org/10.1016/j.crmeth.2022.100192
  3. Mol Cell. 2022 May 05. pii: S1097-2765(22)00375-6. [Epub ahead of print]82(9): 1613-1615
    Coping with starvation: Cysteine keeps mTORC1 suppressed to ensure survival.
    Dohun Kim, Gerta Hoxhaj.
      Jouandin et al. (2022) show that lysosomal-derived cysteine serves as a signal to promote the tricarboxylic acid (TCA) cycle and suppress TORC1 signaling for Drosophila to endure starvation periods.
    DOI:  https://doi.org/10.1016/j.molcel.2022.04.018
  4. Adv Sci (Weinh). 2022 May 04. e2200482
    Regulation of Nucleotide Metabolism with Nutrient-Sensing Nanodrugs for Cancer Therapy.
    Xinye Wang, Wen Su, Yongbin Jiang, Fuhao Jia, Wenping Huang, Jie Zhang, Yue Yin, Hai Wang.
      The continual growth of tumor cells requires considerable nutrient consumption. Methotrexate (MTX) is used to treat certain types of cancer by blocking the DNA and RNA productions through interfering one-carbon metabolism and de novo purine and pyrimidine synthesis. However, treatment of MTX may cause many serious adverse effects, which hamper its clinical application. Herein, the authors synthesize ferrous ions, histidine, and MTX assembled nanoparticles (FHM) to deliver MTX at tumor site and enhance the sensitivity of tumor cells to MTX with histidine catabolism. Furthermore, fasting-mimicking diet (FMD) is applied to intervene in the one-carbon metabolism and enhance the cytotoxicity of MTX. Meanwhile, FMD treatment can significantly augment the cellular uptake and tumor accumulation of FHM nanoparticles. Due to the triple inhibitions of the one-carbon metabolism, the proliferation of tumor cells is strongly disturbed, as which is highly replying on DNA and RNA production. Taken together, a 95% lower dose of MTX adopted in combined therapy significantly inhibits the growth of two types of murine tumors without evident systemic toxicity. This strategy may provide a promising nucleotide metabolism-based nanomedicine for cancer therapy.
    Keywords:  biomolecular nanoparticles; cancer therapy; dietary modification; tumor metabolism
    DOI:  https://doi.org/10.1002/advs.202200482
  5. Cell Metab. 2022 May 03. pii: S1550-4131(22)00134-6. [Epub ahead of print]34(5): 656-657
    A FAsT contribution: Adipocytes rewire their metabolism to acquire immune functions.
    Takumi Kobayashi, Dirk Brenner.
      Adipose tissue has been linked to inflammation and various physiological processes. In this issue of Cell Metabolism, Caputa et al. describe that perinodal adipocytes adapt their metabolism to actively participate in an immune response against intracellular Listeria monocytogenes.
    DOI:  https://doi.org/10.1016/j.cmet.2022.04.007
  6. Proc Natl Acad Sci U S A. 2022 May 10. 119(19): e2120595119
    Hyperpolarized [5-13C,4,4-2H2,5-15N]-L-glutamine provides a means of annotating in vivo metabolic utilization of glutamine.
    Roozbeh Eskandari, Nathaniel Kim, Arsen Mamakhanyan, Michelle Saoi, Guannan Zhang, Marjan Berisaj, Kristin L Granlund, Alex J Poot, Justin Cross, Craig B Thompson, Kayvan R Keshari.
      SignificanceGlutamine is the most abundant amino acid in human plasma, although it is challenging to determine glutamine's metabolic fate noninvasively. In this work, we utilize established chemical methods to develop a platform for imaging glutamine metabolism using hyperpolarized magnetic resonance imaging. Using this strategy, we are able to spatially measure glutaminolysis in vivo as well as develop a biomarker for the inhibition of glutaminase. Combining this biomarker with isotope tracing metabolomics connects this inhibition to reduced glutamine contribution to the tricarboxylic acid cycle. This provides an approach for future imaging of glutamine metabolism in humans.
    Keywords:  cancer metabolism; magnetic resonance imaging; metabolic imaging; pancreatic cancer
    DOI:  https://doi.org/10.1073/pnas.2120595119
  7. STAR Protoc. 2022 Jun 17. 3(2): 101345
    Optimized protocol for stable isotope tracing and steady-state metabolomics in mouse HER2+ breast cancer brain metastasis.
    Pravat Kumar Parida, Mauricio Marquez-Palencia, Akash K Kaushik, Kangsan Kim, Vidhya Nair, Jessica Sudderth, Hieu Vu, Lauren Zacharias, Ralph DeBerardinis, Srinivas Malladi.
      Analyzing the metabolic dependencies of tumor cells is vital for cancer diagnosis and treatment. Here, we describe a protocol for 13C-stable glucose and glutamine isotope tracing in mice HER2+ breast cancer brain metastatic lesions. We describe how to inject cancer cells intracardially to generate brain metastatic lesions in mice. We then detail how to perform 13C-stable isotope infusion in mice with established brain metastasis. Finally, we outline steps for sample collection, processing for metabolite extraction, and analyzing mass spectrometry data. For complete details on the use and execution of this protocol, please refer to Parida et al. (2022).
    Keywords:  Cancer; Cell Biology; Cell culture; Mass Spectrometry; Metabolism; Metabolomics
    DOI:  https://doi.org/10.1016/j.xpro.2022.101345
  8. Cell Metab. 2022 Apr 23. pii: S1550-4131(22)00130-9. [Epub ahead of print]
    Glutaminase inhibition impairs CD8 T cell activation in STK11-/Lkb1-deficient lung cancer.
    Sarah A Best, Patrick M Gubser, Shalini Sethumadhavan, Ariena Kersbergen, Yashira L Negrón Abril, Joshua Goldford, Katherine Sellers, Waruni Abeysekera, Alexandra L Garnham, Jackson A McDonald, Clare E Weeden, Dovile Anderson, David Pirman, Thomas P Roddy, Darren J Creek, Axel Kallies, Gillian Kingsbury, Kate D Sutherland.
      The tumor microenvironment (TME) contains a rich source of nutrients that sustains cell growth and facilitate tumor development. Glucose and glutamine in the TME are essential for the development and activation of effector T cells that exert antitumor function. Immunotherapy unleashes T cell antitumor function, and although many solid tumors respond well, a significant proportion of patients do not benefit. In patients with KRAS-mutant lung adenocarcinoma, KEAP1 and STK11/Lkb1 co-mutations are associated with impaired response to immunotherapy. To investigate the metabolic and immune microenvironment of KRAS-mutant lung adenocarcinoma, we generated murine models that reflect the KEAP1 and STK11/Lkb1 mutational landscape in these patients. Here, we show increased glutamate abundance in the Lkb1-deficient TME associated with CD8 T cell activation in response to anti-PD1. Combination treatment with the glutaminase inhibitor CB-839 inhibited clonal expansion and activation of CD8 T cells. Thus, glutaminase inhibition negatively impacts CD8 T cells activated by anti-PD1 immunotherapy.
    Keywords:  KEAP1; KRAS; STK11/Lkb1; glutaminase; glutamine; immune microenvironment; immunotherapy; lung adenocarcinoma; metabolism
    DOI:  https://doi.org/10.1016/j.cmet.2022.04.003
  9. ACS Appl Mater Interfaces. 2022 May 05.
    Dual Inhibitions on Glucose/Glutamine Metabolisms for Nontoxic Pancreatic Cancer Therapy.
    Yingying Xu, Zhiguo Yu, Hao Fu, Yuedong Guo, Ping Hu, Jianlin Shi.
      Glucose and glutamine are two principal nutrients in mammalian cells that provide energy and biomass for cell growth and proliferation. Especially in cancer cells, glutamine could be a main alternative for energy and biomass supply once glucose metabolism is suppressed. Therefore, single inhibition of enzymes in either glucose metabolism or glutaminolysis, though maybe efficient in vitro, is far from being satisfactory for efficient in vivo cancer therapy. Here, we proposed a new strategy for dual inhibitions on both glucose and glutamine metabolisms concurrently by silencing mutated gene Kras and glutaminase 1 (GLS1) via nanomaterial-based siKras and siGLS1 delivery, rather than conventional highly toxic chemodrugs. Such a combination therapy could overcome the challenge that glucose and glutamine are alternatives to each other in the biosynthesis and energy production for cancer cells, resulting in much elevated treatment efficacy. In addition, layered double hydroxide (LDH), the siRNA carrier, enables an enhanced gene delivery efficiency compared to the commercial transfection agent Lipofectamine 2000. Briefly, Mg-Al LDH nanosheets, loaded with siKras and siGLS1 onto their surfaces by electrostatic adsorption, could release siRNA from lysosomes into the cytoplasm via the proton sponge effect of LDH, favoring the siRNA stability and gene silencing efficiency enhancements. The thus released siRNA could downregulate the expressions of Kras, GLS1, and other enzymes involved in glucose metabolism, resulting in the downregulations of ATP and other metabolites. Such a biosafe LDH/siRNA nanomedicine is able to efficiently suppress the growth of xenografts through cancer cell proliferation suppression, displaying its great potential as a simultaneous glucose/glutamine metabolism coinhibitor for treating pancreatic cancer.
    Keywords:  GLS1; Kras; glucose metabolism inhibition; glutamine metabolism inhibition; layered double hydroxide nanoparticles; pancreatic cancer; siRNA
    DOI:  https://doi.org/10.1021/acsami.2c00111
  10. Cell Mol Immunol. 2022 May 06.
    The deacetylase SIRT2 contributes to autoimmune disease pathogenesis by modulating IL-17A and IL-2 transcription.
    Ryo Hisada, Nobuya Yoshida, Masataka Umeda, Catalina Burbano, Rhea Bhargava, Marc Scherlinger, Michihito Kono, Vasileios C Kyttaris, Suzanne Krishfield, George C Tsokos.
      Aberrant IL-17A expression together with reduced IL-2 production by effector CD4+ T cells contributes to the pathogenesis of systemic lupus erythematosus (SLE). Here, we report that Sirtuin 2 (SIRT2), a member of the family of NAD+-dependent histone deacetylases, suppresses IL-2 production by CD4+ T cells while promoting their differentiation into Th17 cells. Mechanistically, we show that SIRT2 is responsible for the deacetylation of p70S6K, activation of the mTORC1/HIF-1α/RORγt pathway and induction of Th17-cell differentiation. Additionally, SIRT2 was shown to be responsible for the deacetylation of c-Jun and histones at the Il-2 gene, resulting in decreased IL-2 production. We found that the transcription factor inducible cAMP early repressor (ICER), which is overexpressed in T cells from people with SLE and lupus-prone mice, bound directly to the Sirt2 promoter and promoted its transcription. AK-7, a SIRT2 inhibitor, limited the ability of adoptively transferred antigen-specific CD4+ T cells to cause autoimmune encephalomyelitis in mice and limited disease in lupus-prone MRL/lpr mice. Finally, CD4+ T cells from SLE patients exhibited increased expression of SIRT2, and pharmacological inhibition of SIRT2 in primary CD4+ T cells from patients with SLE attenuated the ability of these cells to differentiate into Th17 cells and promoted the generation of IL-2-producing T cells. Collectively, these results suggest that SIRT2-mediated deacetylation is essential in the aberrant expression of IL-17A and IL-2 and that SIRT2 may be a promising molecular target for new SLE therapies.
    Keywords:  IL-17A; IL-2; SIRT2; Systemic lupus erythematosus
    DOI:  https://doi.org/10.1038/s41423-022-00874-1
  11. Front Immunol. 2022 ;13 850856
    The Give-and-Take Interaction Between the Tumor Microenvironment and Immune Cells Regulating Tumor Progression and Repression.
    Simon Pernot, Serge Evrard, Abdel-Majid Khatib.
      A fundamental concern of the majority of cancer scientists is related to the identification of mechanisms involved in the evolution of neoplastic cells at the cellular and molecular level and how these processes are able to control cancer cells appearance and death. In addition to the genome contribution, such mechanisms involve reciprocal interactions between tumor cells and stromal cells within the tumor microenvironment (TME). Indeed, tumor cells survival and growth rely on dynamic properties controlling pro and anti-tumorigenic processes. The anti-tumorigenic function of the TME is mainly regulated by immune cells such as dendritic cells, natural killer cells, cytotoxic T cells and macrophages and normal fibroblasts. The pro-tumorigenic function is also mediated by other immune cells such as myeloid-derived suppressor cells, M2-tumor-associated macrophages (TAMs) and regulatory T (Treg) cells, as well as carcinoma-associated fibroblasts (CAFs), adipocytes (CAA) and endothelial cells. Several of these cells can show both, pro- and antitumorigenic activity. Here we highlight the importance of the reciprocal interactions between tumor cells and stromal cells in the self-centered behavior of cancer cells and how these complex cellular interactions control tumor progression and repression.
    Keywords:  metastatic dissemination; neoplastic evolution; philosophy of cancer; reciprocal interaction; stromal cells secreted molecules; tumor microenvironment
    DOI:  https://doi.org/10.3389/fimmu.2022.850856
  12. RSC Adv. 2020 May 27. 10(35): 21000-21008
    Glycolytic and lipid oxidative metabolic programs are essential for freshly-isolated regulatory T cells in mice with sepsis.
    Xiaomei Zhu, WenQing Ji, Shubin Guo, Di Zhu, Yue Yang, Xin Liu.
      Immunometabolism determines the fate and function of regulatory T cells. The metabolic phenotype of regulatory T cells (Treg) is affected by various factors. The relationship between Treg metabolism and function of mice with sepsis is not clear. We used liquid chromatography and tandem mass spectrometry (LC-MS/MS) to analyze the metabolic profiles of freshly-isolated spleen Treg cells in mice with sepsis. It was found that in severe infection, activated Treg cells depend on glycolysis and fatty acid oxidation, and inhibition of metabolic pathways has a significant impact on the number and quality of Treg cells. Understanding the metabolic characteristics of Treg cells in the real environment in the body helps to grasp the function of Treg cells and even the overall immune status. Targeting the metabolic pathway of Treg may provide a new method for the treatment of sepsis.
    DOI:  https://doi.org/10.1039/d0ra01947j
  13. Curr Res Immunol. 2021 ;2 132-141
    Tumor-infiltrating T-regulatory cells adapt to altered metabolism to promote tumor-immune escape.
    Tania Sarkar, Subhanki Dhar, Gaurisankar Sa.
      Tumor mass and its microenvironment alter host immune system in various ways to promote tumor growth. One of the modifications is evasion of immune surveillance by augmenting the number of Tregs in tumor vicinity. Elevated levels of Tregs are seen in peripheral circulation and tumor tissue of cancer patients. Cancer cells release several chemokines to attract Tregs in tumor-site. Infiltration of Tregs has clinical significance because being immunosuppressive infiltrating Tregs suppress other immune cells making the tumor microenvironment favorable for tumor growth. On the other hand, infiltrating Tregs show metabolic alteration in tumor microenvironment which allows their selective survival over the others. Persistence of Tregs in the tumor microenvironment and subsequent immunosuppression makes Tregs a potential therapeutic obstacle and the reason behind the failure of immunotherapy. In this review, we emphasize the recent development in the metabolic adaptation of tumor-infiltrating Tregs and the therapeutic approaches to boost immunity against cancer.
    Keywords:  Anti-Tumor immunity; CCL/CXCL, Chemokine ligand; CCR/CXCR, Chemokine receptor; FOXP3, Forkhead box P3; IL, Interleukin; Immune-suppression; Metabolism; NK cell, Natural killer cell; T-regulatory cell; TGFβ, Transforming growth factor-beta; TME, Tumor microenvironment; Treg, T-regulatory cell; Tumor microenvironment
    DOI:  https://doi.org/10.1016/j.crimmu.2021.08.002
  14. Cell Metab. 2022 May 03. pii: S1550-4131(22)00133-4. [Epub ahead of print]34(5): 775-782.e9
    Glycine decarboxylase maintains mitochondrial protein lipoylation to support tumor growth.
    Dzmitry Mukha, Mariam Fokra, Alona Feldman, Boris Sarvin, Nikita Sarvin, Keren Nevo-Dinur, Elazar Besser, Elior Hallo, Elina Aizenshtein, Zachary T Schug, Tomer Shlomi.
      The folic acid cycle mediates the transfer of one-carbon (1C) units to support nucleotide biosynthesis. While the importance of serine as a mitochondrial and cytosolic donor of folate-mediated 1C units in cancer cells has been thoroughly investigated, a potential role of glycine oxidation remains unclear. We developed an approach for quantifying mitochondrial glycine cleavage system (GCS) flux by combining stable and radioactive isotope tracing with computational flux decomposition. We find high GCS flux in hepatocellular carcinoma (HCC), supporting nucleotide biosynthesis. Surprisingly, other than supplying 1C units, we found that GCS is important for maintaining protein lipoylation and mitochondrial activity. Genetic silencing of glycine decarboxylase inhibits the lipoylation and activity of pyruvate dehydrogenase and impairs tumor growth, suggesting a novel drug target for HCC. Considering the physiological role of liver glycine cleavage, our results support the notion that tissue of origin plays an important role in tumor-specific metabolic rewiring.
    Keywords:  GCS; GLDC; PDH; glycine cleavage system; glycine decarboxylase; hepatocellular carcinoma; one-carbon metabolism; protein P; protein lipoylation; pyruvate dehydrogenase
    DOI:  https://doi.org/10.1016/j.cmet.2022.04.006
  15. Nat Commun. 2022 May 05. 13(1): 2483
    Combinatorial GxGxE CRISPR screen identifies SLC25A39 in mitochondrial glutathione transport linking iron homeostasis to OXPHOS.
    Xiaojian Shi, Bryn Reinstadler, Hardik Shah, Tsz-Leung To, Katie Byrne, Luanna Summer, Sarah E Calvo, Olga Goldberger, John G Doench, Vamsi K Mootha, Hongying Shen.
      The SLC25 carrier family consists of 53 transporters that shuttle nutrients and co-factors across mitochondrial membranes. The family is highly redundant and their transport activities coupled to metabolic state. Here, we use a pooled, dual CRISPR screening strategy that knocks out pairs of transporters in four metabolic states - glucose, galactose, OXPHOS inhibition, and absence of pyruvate - designed to unmask the inter-dependence of these genes. In total, we screen 63 genes in four metabolic states, corresponding to 2016 single and pair-wise genetic perturbations. We recover 19 gene-by-environment (GxE) interactions and 9 gene-by-gene (GxG) interactions. One GxE interaction hit illustrates that the fitness defect in the mitochondrial folate carrier (SLC25A32) KO cells is genetically buffered in galactose due to a lack of substrate in de novo purine biosynthesis. GxG analysis highlights a buffering interaction between the iron transporter SLC25A37 (A37) and the poorly characterized SLC25A39 (A39). Mitochondrial metabolite profiling, organelle transport assays, and structure-guided mutagenesis identify A39 as critical for mitochondrial glutathione (GSH) import. Functional studies reveal that A39-mediated glutathione homeostasis and A37-mediated mitochondrial iron uptake operate jointly to support mitochondrial OXPHOS. Our work underscores the value of studying family-wide genetic interactions across different metabolic environments.
    DOI:  https://doi.org/10.1038/s41467-022-30126-9
  16. NPJ Breast Cancer. 2022 May 04. 8(1): 59
    Lipid exposure activates gene expression changes associated with estrogen receptor negative breast cancer.
    Shivangi Yadav, Ranya Virk, Carolina H Chung, Mariana Bustamante Eduardo, David VanDerway, Duojiao Chen, Kirsten Burdett, Hongyu Gao, Zexian Zeng, Manish Ranjan, Gannon Cottone, Xiaoling Xuei, Sriram Chandrasekaran, Vadim Backman, Robert Chatterton, Seema Ahsan Khan, Susan E Clare.
      Improved understanding of local breast biology that favors the development of estrogen receptor negative (ER-) breast cancer (BC) would foster better prevention strategies. We have previously shown that overexpression of specific lipid metabolism genes is associated with the development of ER- BC. We now report results of exposure of MCF-10A and MCF-12A cells, and mammary organoids to representative medium- and long-chain polyunsaturated fatty acids. This exposure caused a dynamic and profound change in gene expression, accompanied by changes in chromatin packing density, chromatin accessibility, and histone posttranslational modifications (PTMs). We identified 38 metabolic reactions that showed significantly increased activity, including reactions related to one-carbon metabolism. Among these reactions are those that produce S-adenosyl-L-methionine for histone PTMs. Utilizing both an in-vitro model and samples from women at high risk for ER- BC, we show that lipid exposure engenders gene expression, signaling pathway activation, and histone marks associated with the development of ER- BC.
    DOI:  https://doi.org/10.1038/s41523-022-00422-0
  17. Sci Signal. 2022 May 03. 15(732): eabq7456
    Letting go of damaged mitochondria.
    Wei Wong.
      Thermogenesis requires that macrophages digest damaged mitochondria released by brown adipocytes.
    DOI:  https://doi.org/10.1126/scisignal.abq7456
  18. Cell Metab. 2022 May 03. pii: S1550-4131(22)00135-8. [Epub ahead of print]34(5): 747-760.e6
    Intracellular infection and immune system cues rewire adipocytes to acquire immune function.
    George Caputa, Mai Matsushita, David E Sanin, Agnieszka M Kabat, Joy Edwards-Hicks, Katarzyna M Grzes, Roland Pohlmeyer, Michal A Stanczak, Angela Castoldi, Jovana Cupovic, Aaron J Forde, Petya Apostolova, Maximilian Seidl, Nikki van Teijlingen Bakker, Matteo Villa, Francesc Baixauli, Andrea Quintana, Alexandra Hackl, Lea Flachsmann, Fabian Hässler, Jonathan D Curtis, Annette E Patterson, Philipp Henneke, Erika L Pearce, Edward J Pearce.
      Adipose tissue (AT) plays a central role in systemic metabolic homeostasis, but its function during bacterial infection remains unclear. Following subcutaneous bacterial infection, adipocytes surrounding draining lymph nodes initiated a transcriptional response indicative of stimulation with IFN-γ and a shift away from lipid metabolism toward an immunologic function. Natural killer (NK) and invariant NK T (iNKT) cells were identified as sources of infection-induced IFN-γ in perinodal AT (PAT). IFN-γ induced Nos2 expression in adipocytes through a process dependent on nuclear-binding oligomerization domain 1 (NOD1) sensing of live intracellular bacteria. iNOS expression was coupled to metabolic rewiring, inducing increased diversion of extracellular L-arginine through the arginosuccinate shunt and urea cycle to produce nitric oxide (NO), directly mediating bacterial clearance. In vivo, control of infection in adipocytes was dependent on adipocyte-intrinsic sensing of IFN-γ and expression of iNOS. Thus, adipocytes are licensed by innate lymphocytes to acquire anti-bacterial functions during infection.
    Keywords:  IFN-γ; NK cells; NOD1; NOS2; adipocyte; iNK T cells; infection; lymph node; metabolism; perinodal adipose tissue
    DOI:  https://doi.org/10.1016/j.cmet.2022.04.008
  19. iScience. 2022 May 20. 25(5): 104209
    IP3R-mediated Ca2+ signaling controls B cell proliferation through metabolic reprogramming.
    Huayuan Tang, Yali Li, Shijia Wang, Jing Ji, Xiangbin Zhu, Yutong Bao, Can Huang, Ye Luo, Lei Huang, Yan Gao, Chaoliang Wei, Jie Liu, Xi Fang, Lu Sun, Kunfu Ouyang.
      Emerging evidence shows that metabolic regulation may be a critical mechanism in B cell activation and function. As targets of several most widely used immunosuppressants, Ca2+ signaling and calcineurin may play an important role in regulating B cell metabolism. Here, we demonstrate that IP3R-mediated Ca2+ signaling and calcineurin regulate B cell proliferation and survival by activating metabolic reprogramming in response to B cell receptor (BCR) stimulation. Both IP3R-triple-knockout (IP3R-TKO) and calcineurin inhibition dramatically suppress the metabolic switch in oxidative phosphorylation and glycolysis of stimulated B cells through regulation of glucose uptake, glycolytic enzyme expression, and mitochondrial remodeling, leading to impaired cell-cycle entry and survival. In addition, IP3R-Ca2+ acts as a master regulator of the calcineurin-MEF2C-Myc pathway in driving B cell metabolic adaptations. As genetic defects of IP3Rs were recently identified as a new class of inborn errors of immunity, these results have important implications for understanding the pathogenesis of such diseases.
    Keywords:  Cell biology; Immune response; Immunology
    DOI:  https://doi.org/10.1016/j.isci.2022.104209
  20. Sci Rep. 2022 May 06. 12(1): 7450
    Rheumatoid arthritis T cell and muscle oxidative metabolism associate with exercise-induced changes in cardiorespiratory fitness.
    Brian J Andonian, Alec Koss, Timothy R Koves, Elizabeth R Hauser, Monica J Hubal, David M Pober, Janet M Lord, Nancie J MacIver, E William St Clair, Deborah M Muoio, William E Kraus, David B Bartlett, Kim M Huffman.
      Rheumatoid arthritis (RA) T cells drive autoimmune features via metabolic reprogramming that reduces oxidative metabolism. Exercise training improves cardiorespiratory fitness (i.e., systemic oxidative metabolism) and thus may impact RA T cell oxidative metabolic function. In this pilot study of RA participants, we took advantage of heterogeneous responses to a high-intensity interval training (HIIT) exercise program to identify relationships between improvements in cardiorespiratory fitness with changes in peripheral T cell and skeletal muscle oxidative metabolism. In 12 previously sedentary persons with seropositive RA, maximal cardiopulmonary exercise tests, fasting blood, and vastus lateralis biopsies were obtained before and after 10 weeks of HIIT. Following HIIT, improvements in RA cardiorespiratory fitness were associated with changes in RA CD4 + T cell basal and maximal respiration and skeletal muscle carnitine acetyltransferase (CrAT) enzyme activity. Further, changes in CD4 + T cell respiration were associated with changes in naïve CD4 + CCR7 + CD45RA + T cells, muscle CrAT, and muscle medium-chain acylcarnitines and fat oxidation gene expression profiles. In summary, modulation of cardiorespiratory fitness and molecular markers of skeletal muscle oxidative metabolism during exercise training paralleled changes in T cell metabolism. Exercise training that improves RA cardiorespiratory fitness may therefore be valuable in managing pathologically related immune and muscle dysfunction.Trial registration: ClinicalTrials.gov, NCT02528344. Registered on 19 August 2015.
    DOI:  https://doi.org/10.1038/s41598-022-11458-4
  21. J Clin Invest. 2022 May 02. pii: e152391. [Epub ahead of print]132(9):
    Cyclooxygenase-2 in adipose tissue macrophages limits adipose tissue dysfunction in obese mice.
    Yu Pan, Shirong Cao, Jiaqi Tang, Juan P Arroyo, Andrew S Terker, Yinqiu Wang, Aolei Niu, Xiaofeng Fan, Suwan Wang, Yahua Zhang, Ming Jiang, David H Wasserman, Ming-Zhi Zhang, Raymond C Harris.
      Obesity-associated complications are causing increasing morbidity and mortality worldwide. Expansion of adipose tissue in obesity leads to a state of low-grade chronic inflammation and dysregulated metabolism, resulting in insulin resistance and metabolic syndrome. Adipose tissue macrophages (ATMs) accumulate in obesity and are a source of proinflammatory cytokines that further aggravate adipocyte dysfunction. Macrophages are rich sources of cyclooxygenase (COX), the rate limiting enzyme for prostaglandin E2 (PGE2) production. When mice were fed a high-fat diet (HFD), ATMs increased expression of COX-2. Selective myeloid cell COX-2 deletion resulted in increased monocyte recruitment and proliferation of ATMs, leading to increased proinflammatory ATMs with decreased phagocytic ability. There were increased weight gain and adiposity, decreased peripheral insulin sensitivity and glucose utilization, increased adipose tissue inflammation and fibrosis, and abnormal adipose tissue angiogenesis. HFD pair-feeding led to similar increases in body weight, but mice with selective myeloid cell COX-2 still exhibited decreased peripheral insulin sensitivity and glucose utilization. Selective myeloid deletion of the macrophage PGE2 receptor subtype, EP4, produced a similar phenotype, and a selective EP4 agonist ameliorated the metabolic abnormalities seen with ATM COX-2 deletion. Therefore, these studies demonstrated that an ATM COX-2/PGE2/EP4 axis plays an important role in inhibiting adipose tissue dysfunction.
    Keywords:  Adipose tissue; Eicosanoids; Inflammation; Metabolism; Obesity
    DOI:  https://doi.org/10.1172/JCI152391
  22. Blood Adv. 2022 May 02. pii: bloodadvances.2021005776. [Epub ahead of print]
    IFNγ Regulates NAD+ Metabolism to Promote the Respiratory Burst in Human Monocytes.
    Katelyn J McCann, Stephen M Christensen, Devon H Colby, Peter J McGuire, Ian A Myles, Christa S Zerbe, Clifton L Dalgard, Gauthaman Sukumar, Warren J Leonard, Beth A McCormick, Steven M Holland.
      IFNγ is an essential and pleiotropic activator of human monocytes, but little is known about the changes in cellular metabolism required for IFNγ-induced activation. We sought to elucidate the mechanisms by which IFNγ reprograms monocyte metabolism to support its immunologic activities. We found that IFNγ increased oxygen consumption rates (OCR) in monocytes, indicative of reactive oxygen species generation by both mitochondria and NADPH oxidase. Transcriptional profiling revealed that this oxidative phenotype was driven by IFNγ-induced reprogramming of NAD+ metabolism, which is dependent on nicotinamide phosphoribosyltransferase (NAMPT)-mediated NAD+ salvage to generate NADH and NADPH for oxidation by mitochondrial complex I and NADPH oxidase, respectively. Consistent with this pathway, monocytes from patients with gain-of-function mutations in STAT1 demonstrated higher than normal OCR. Whereas chemical or genetic disruption of mitochondrial complex I (rotenone treatment or Leigh Syndrome patient monocytes) or NADPH oxidase (DPI treatment or chronic granulomatous disease (CGD) patient monocytes) reduced OCR. Interestingly, inhibition of NAMPT in healthy monocytes completely abrogated the IFNγ-induced oxygen consumption, comparable to levels observed in CGD monocytes. These data identify an IFNγ-induced, NAMPT-dependent, NAD+ salvage pathway that is critical for IFNγ activation of human monocytes.
    DOI:  https://doi.org/10.1182/bloodadvances.2021005776
  23. iScience. 2022 May 20. 25(5): 104231
    Trans-omics analysis of insulin action reveals a cell growth subnetwork which co-regulates anabolic processes.
    Akira Terakawa, Yanhui Hu, Toshiya Kokaji, Katsuyuki Yugi, Keigo Morita, Satoshi Ohno, Yifei Pan, Yunfan Bai, Andrey A Parkhitko, Xiaochun Ni, John M Asara, Martha L Bulyk, Norbert Perrimon, Shinya Kuroda.
      Insulin signaling promotes anabolic metabolism to regulate cell growth through multi-omic interactions. To obtain a comprehensive view of the cellular responses to insulin, we constructed a trans-omic network of insulin action in Drosophila cells that involves the integration of multi-omic data sets. In this network, 14 transcription factors, including Myc, coordinately upregulate the gene expression of anabolic processes such as nucleotide synthesis, transcription, and translation, consistent with decreases in metabolites such as nucleotide triphosphates and proteinogenic amino acids required for transcription and translation. Next, as cell growth is required for cell proliferation and insulin can stimulate proliferation in a context-dependent manner, we integrated the trans-omic network with results from a CRISPR functional screen for cell proliferation. This analysis validates the role of a Myc-mediated subnetwork that coordinates the activation of genes involved in anabolic processes required for cell growth.
    Keywords:  In silico biology; Omics; Systems biology
    DOI:  https://doi.org/10.1016/j.isci.2022.104231
  24. Cancer Res. 2022 May 02. pii: canres.3868.2021. [Epub ahead of print]
    Targeting BCAT1 combined with α-ketoglutarate triggers metabolic synthetic lethality in glioblastoma.
    Bo Zhang, Hui Peng, Mi Zhou, Lei Bao, Chenliang Wang, Feng Cai, Hongxia Zhang, Jennifer E Wang, Yanling Niu, Yan Chen, Yijie Wang, Kimmo Hatanpaa, John A Copland, Ralph J DeBerardinis, Yingfei Wang, Weibo Luo.
      Branched-chain amino acid transaminase 1 (BCAT1) is upregulated selectively in human isocitrate dehydrogenase (IDH) wildtype (WT) but not mutant glioblastoma multiforme (GBM) and promotes IDHWT GBM growth. Through a metabolic synthetic lethal screen, we report here that α-ketoglutarate (AKG) kills IDHWT GBM cells when BCAT1 protein is lost, which is reversed by re-expression of BCAT1 or supplementation with branched-chain α-ketoacids (BCKAs), downstream metabolic products of BCAT1. In patient-derived IDHWT GBM tumors in vitro and in vivo, co-treatment of BCAT1 inhibitor gabapentin and AKG resulted in synthetic lethality. However, AKG failed to evoke a synthetic lethal effect with loss of BCAT2, BCKDHA, or GPT2 in IDHWT GBM cells. Mechanistically, loss of BCAT1 increased the NAD+/NADH ratio but impaired oxidative phosphorylation, mTORC1 activity, and nucleotide biosynthesis. These metabolic alterations were synergistically augmented by AKG treatment, thereby causing mitochondrial dysfunction and depletion of cellular building blocks, including ATP, nucleotides, and proteins. Partial restoration of ATP, nucleotides, proteins, and mTORC1 activity by BCKA supplementation prevented IDHWT GBM cell death conferred by the combination of BCAT1 loss and AKG. These findings define a targetable metabolic vulnerability in the most common subset of GBM that is currently incurable.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-21-3868
  25. J Nanobiotechnology. 2022 May 06. 20(1): 216
    Simultaneous glutamine metabolism and PD-L1 inhibition to enhance suppression of triple-negative breast cancer.
    Yuxia Tang, Siqi Wang, Yang Li, Chen Yuan, Jie Zhang, Ziqing Xu, Yongzhi Hu, Haibin Shi, Shouju Wang.
      Blockade of programmed cell death 1 ligand (PD-L1) has been used to treat triple-negative breast cancer (TNBC), and various strategies are under investigation to improve the treatment response rate. Inhibition of glutamine metabolism can reduce the massive consumption of glutamine by tumor cells and meet the demand for glutamine by lymphocytes in tumors, thereby improving the anti-tumor effect on the PD-L1 blockade therapy. Here, molybdenum disulfide (MoS2) was employed to simultaneously deliver anti-PDL1 antibody (aPDL1) and V9302 to boost the anti-tumor immune response in TNBC cells. The characterization results show that MoS2 has a dispersed lamellar structure with a size of about 181 nm and a size of 232 nm after poly (L-lysine) (PLL) modification, with high stability and biocompatibility. The loading capacity of aPDL1 and V9302 are 3.84% and 24.76%, respectively. V9302 loaded MoS2 (MoS2-V9302) can effectively kill 4T1 cells and significantly reduce glutamine uptake of tumor cells. It slightly increases CD8+ cells in the tumor and promotes CD8+ cells from the tumor edge into the tumor core. In vivo studies demonstrate that the combination of aPDL1 and V9302 (MoS2-aPDL1-V9302) can strongly inhibit the growth of TNBC 4T1 tumors. Interestingly, after the treatment of MoS2-aPDL1-V9302, glutamine levels in tumor interstitial fluid increased. Subsequently, subtypes of cytotoxic T cells (CD8+) in the tumors were analyzed according to two markers of T cell activation, CD69, and CD25, and the results reveal a marked increase in the proportion of activated T cells. The levels of cytokines in the corresponding tumor interstitial fluid are also significantly increased. Additionally, during the treatment, the body weights of the mice remain stable, the main indicators of liver and kidney function in the blood do not increase significantly, and there are no obvious lesions in the main organs, indicating low systemic toxicity. In conclusion, our study provides new insights into glutamine metabolism in the tumor microenvironment affects immune checkpoint blockade therapy in TNBC, and highlights the potential clinical implications of combining glutamine metabolism inhibition with immune checkpoint blockade in the treatment of TNBC.
    Keywords:  Anti-PDL1; Glutamine metabolism inhibitor; MoS2 nanosheets; Triple-negative breast cancer; V9302
    DOI:  https://doi.org/10.1186/s12951-022-01424-7
  26. Front Immunol. 2022 ;13 884126
    The Adipose Tissue Macrophages Central to Adaptive Thermoregulation.
    Md Shamim Rahman, Heejin Jun.
      White fat stores excess energy, and thus its excessive expansion causes obesity. However, brown and beige fat, known as adaptive thermogenic fat, dissipates energy in the form of heat and offers a therapeutic potential to counteract obesity and metabolic disorders. The fat type-specific biological function is directed by its unique tissue microenvironment composed of immune cells, endothelial cells, pericytes and neuronal cells. Macrophages are major immune cells resident in adipose tissues and gained particular attention due to their accumulation in obesity as the primary source of inflammation. However, recent studies identified macrophages' unique role and regulation in thermogenic adipose tissues to regulate energy expenditure and systemic energy homeostasis. This review presents the current understanding of macrophages in thermogenic fat niches with an emphasis on discrete macrophage subpopulations central to adaptive thermoregulation.
    Keywords:   brown adipocyte ; adipose tissue macrophage; beige adipocyte; obesity; thermogenesis
    DOI:  https://doi.org/10.3389/fimmu.2022.884126
  27. Biofabrication. 2022 May 05.
    Mimicking Tumor Microenvironment by 3D Bioprinting: 3D Cancer Modeling.
    Priyanshu Shukla, Sriya Yeleswarapu, Marcel Heinrich, Jai Prakash, Falguni Pati.
      The tumor microenvironment typically comprises cancer cells, tumor vasculature, stromal components like fibroblasts, and host immune cells that assemble to support tumorigenesis. However, preexisting classic cancer models like 2D cell culture methods, 3D cancer spheroids, and tumor organoids seem to lack essential tumor microenvironment components. 3D bioprinting offers enormous advantages for developing in vitro tumor models by allowing user-controlled deposition of multiple biomaterials, cells, and biomolecules in a predefined architecture. This review highlights the recent developments in 3D cancer modeling using different bioprinting techniques to recreate the TME. 3D bioprinters enable fabrication of high-resolution microstructures to reproduce TME intricacies. Furthermore, 3D bioprinted models can be applied as a preclinical model for versatile research applications in the tumor biology and pharmaceutical industries. These models provide an opportunity to develop high-throughput drug screening platforms and can further be developed to suit individual patient requirements hence giving a boost to the field of personalized anti-cancer therapeutics. We underlined the various ways the existing studies have tried to mimic the TME, mimic the hallmark events of cancer growth and metastasis within the 3D bioprinted models and showcase the 3D drug-tumor interaction and further utilization of such models to develop personalized medicine.
    Keywords:  3D Bioprinting; Cancer-on-chip; Classic 3D cancer model; Organoids; Tumor Microenvironment
    DOI:  https://doi.org/10.1088/1758-5090/ac6d11
  28. Front Immunol. 2022 ;13 850093
    The Interplay Between Inflammation and Stromal Components in Pancreatic Cancer.
    Ying Li, Jing Wang, Haiyan Wang, Shaoqiang Zhang, Yingxin Wei, Shanglong Liu.
      Inflammation involves interactions between various immune cells, inflammatory cells, chemokines and cytokines in pancreatic cancer. Cancer cells as well as surrounding stromal and inflammatory cells establish an inflammatory tumor microenvironment (TME). Inflammation is closely associated with immunity. Meanwhile, immune cells are involved in both inflammation and immune response. Tumor-promoting inflammation and tumor-suppressive immunity are two main characteristics of the tumor microenvironment in pancreatic cancer. Yet, the mechanism of inflammation and immune response in pancreatic cancer development is still unclear due to the dual role of some cytokines and the complicated crosstalk between tumor and stromal components in TME. In this review, we outline the principal cytokines and stromal cells in the pancreatic TME that are involved in the tumor-promoting and immunosuppressive effects of inflammation, and discuss the interaction between inflammation and stromal components in pancreatic cancer progression. Moreover, the clinical approaches based on targeting TME in pancreatic cancer are also summarized. Defining the mechanisms of interplay between inflammation and stromal components will be essential for further development of anti-cancer therapies.
    Keywords:  crosstalk; immune response; inflammation; pancreatic cancer; tumor microenvironment
    DOI:  https://doi.org/10.3389/fimmu.2022.850093
  29. Cell Metab. 2022 May 03. pii: S1550-4131(22)00132-2. [Epub ahead of print]34(5): 658-660
    Krebs takes a turn at cell differentiation.
    Stanisław Deja, Peter A Crawford, Shawn C Burgess.
      In a recent issue of Nature, Arnold et al. report that the partitioning of citrate away from the oxidative steps of the tricarboxylic acid cycle and into the citrate-malate shuttle is essential for mouse embryonic stem cell differentiation. Their findings highlight a crucial role for metabolic regulation in developmental biology.
    DOI:  https://doi.org/10.1016/j.cmet.2022.04.005
  30. Biochim Biophys Acta Biomembr. 2022 Apr 30. pii: S0005-2736(22)00090-6. [Epub ahead of print] 183951
    OxLDL induces membrane structure rearrangement leading to biomechanics alteration and migration deficiency in macrophage.
    Luisa Rezende, Natalia Fernanda Do Couto, Weslley Fernandes-Braga, Yulia Epshtein, Jacqueline Isaura Alvarez-Leite, Irena Levitan, Luciana de Oliveira Andrade.
      Cholesterol sequestration from plasma membrane has been shown to induce lipid packing disruption, causing actin cytoskeleton reorganization and polymerization, increasing cell stiffness and inducing lysosomal exocytosis in non-professional phagocytes. Similarly, oxidized form of low-density lipoprotein (oxLDL) has also been shown to disrupt lipid organization and packing in endothelial cells, leading to biomechanics alterations that interfere with membrane injury and repair. For macrophages, much is known about oxLDL effects in cell activation, cytokine production and foam cell formation. However, little is known about its impact in the organization of macrophage membrane structured domains and cellular mechanics, the focus of the present study. Treatment of bone marrow-derived macrophages (BMDM) with oxLDL not only altered membrane structure, and potentially the distribution of raft domains, but also induced actin rearrangement, diffuse integrin distribution and cell shrinkage, similarly to observed upon treatment of these cells with MβCD. Those alterations led to decreased migration efficiency. For both treatments, higher co-localization of actin cytoskeleton and GM1 was observed, indicating a similar mechanism of action involving raft-like domain dynamics. Lastly, like MβCD treatment, oxLDL also induced lysosomal spreading in BMDM. We propose that OxLDL induced re-organization of membrane/cytoskeleton complex in macrophages can be attributed to the insertion of oxysterols into the membrane, which lead to changes in lipid organization and disruption of membrane structure, similar to the effect of cholesterol depletion by MβCD treatment. These results indicate that oxLDL can induce physical alterations in the complex membrane/cytoskeleton of macrophages, leading to significant biomechanical changes that compromise cell behavior.
    Keywords:  Actin; Cell migration; Macrophage; Membrane domains; oxLDL
    DOI:  https://doi.org/10.1016/j.bbamem.2022.183951
  31. Mol Ther Oncolytics. 2022 Jun 16. 25 98-120
    Noncoding RNA-mediated macrophage and cancer cell crosstalk in hepatocellular carcinoma.
    Zhixia Zhou, Zhan Wang, Jie Gao, Zhijuan Lin, Yin Wang, Peipei Shan, Mengkun Li, Tingting Zhou, Peifeng Li.
      The tumor microenvironment (TME) is a well-recognized system that plays an essential role in tumor initiation, development, and progression. Intense intercellular communication between tumor cells and other cells (especially macrophages) occurs in the TME and is mediated by cell-to-cell contact and/or soluble messengers. Emerging evidence indicates that noncoding RNAs (ncRNAs) are critical regulators of the relationship between cells within the TME. In this review, we provide an update on the regulation of ncRNAs (primarily micro RNAs [miRNAs], long ncRNAs [lncRNAs], and circular RNAs [circRNAs]) in the crosstalk between macrophages and tumor cells in hepatocellular carcinoma (HCC). These ncRNAs are derived from macrophages or tumor cells and act as oncogenes or tumor suppressors, contributing to tumor progression not only by regulating the physiological and pathological processes of tumor cells but also by controlling macrophage infiltration, activation, polarization, and function. Herein, we also explore the options available for clinical therapeutic strategies targeting crosstalk-related ncRNAs to treat HCC. A better understanding of the relationship between macrophages and tumor cells mediated by ncRNAs will uncover new diagnostic biomarkers and pharmacological targets in cancer.
    Keywords:  circular RNA (circRNA); hepatocellular carcinoma (HCC); long noncoding RNA (lncRNA); microRNA (miRNA); noncoding RNA (ncRNA); tumor microenvironment (TME); tumor-associated macrophage (TAM)
    DOI:  https://doi.org/10.1016/j.omto.2022.03.002
  32. Cell Discov. 2022 May 03. 8(1): 40
    Dynamic O-GlcNAcylation coordinates ferritinophagy and mitophagy to activate ferroptosis.
    Fan Yu, Qianping Zhang, Hanyu Liu, Jinming Liu, Song Yang, Xiaofan Luo, Wei Liu, Hao Zheng, Qiqi Liu, Yunxi Cui, Guo Chen, Yanjun Li, Xinglu Huang, Xiyun Yan, Jun Zhou, Quan Chen.
      Ferroptosis is a regulated iron-dependent cell death characterized by the accumulation of lipid peroxidation. A myriad of facets linking amino acid, lipid, redox, and iron metabolisms were found to drive or to suppress the execution of ferroptosis. However, how the cells decipher the diverse pro-ferroptotic stress to activate ferroptosis remains elusive. Here, we report that protein O-GlcNAcylation, the primary nutrient sensor of glucose flux, orchestrates both ferritinophagy and mitophagy for ferroptosis. Following the treatment of ferroptosis stimuli such as RSL3, a commonly used ferroptosis inducer, there exists a biphasic change of protein O-GlcNAcylation to modulate ferroptosis. Pharmacological or genetic inhibition of O-GlcNAcylation promoted ferritinophagy, resulting in the accumulation of labile iron towards mitochondria. Inhibition of O-GlcNAcylation resulted in mitochondria fragmentation and enhanced mitophagy, providing an additional source of labile iron and rendering the cell more sensitive to ferroptosis. Mechanistically, we found that de-O-GlcNAcylation of the ferritin heavy chain at S179 promoted its interaction with NCOA4, the ferritinophagy receptor, thereby accumulating labile iron for ferroptosis. Our findings reveal a previously uncharacterized link of dynamic O-GlcNAcylation with iron metabolism and decision-making for ferroptosis, thus offering potential therapeutic intervention for fighting disease.
    DOI:  https://doi.org/10.1038/s41421-022-00390-6
  33. Inflamm Regen. 2022 May 01. 42(1): 13
    Molecular mechanism of crosstalk between immune and metabolic systems in metabolic syndrome.
    Rumi Hachiya, Miyako Tanaka, Michiko Itoh, Takayoshi Suganami.
      Chronic inflammation is currently considered as a molecular basis of metabolic syndrome. Particularly, obesity-induced inflammation in adipose tissue is the origin of chronic inflammation of metabolic syndrome. Adipose tissue contains not only mature adipocytes with large lipid droplets, but also a variety of stromal cells including adipocyte precursors, vascular component cells, immune cells, and fibroblasts. However, crosstalk between those various cell types in adipose tissue in obesity still remains to be fully understood. We focus on two innate immune receptors, Toll-like receptor 4 (TLR4) and macrophage-inducible C-type lectin (Mincle). We provided evidence that adipocyte-derived saturated fatty acids (SFAs) activate macrophage TLR4 signaling pathway, thereby forming a vicious cycle of inflammatory responses during the development of obesity. Intriguingly, the TLR4 signaling pathway is modulated metabolically and epigenetically: SFAs augment TLR4 signaling through the integrated stress response and chromatin remodeling, such as histone methylation, regulates dynamic transcription patterns downstream of TLR4 signaling. Another innate immune receptor Mincle senses cell death, which is a trigger of chronic inflammatory diseases including obesity. Macrophages form a histological structure termed "crown-like structure (CLS)", in which macrophages surround dead adipocytes to engulf cell debris and residual lipids. Mincle is exclusively expressed in macrophages forming the CLS in obese adipose tissue and regulates adipocyte death-triggered adipose tissue fibrosis. In addition to adipose tissue, we found a structure similar to CLS in the liver of nonalcoholic steatohepatitis (NASH) and the kidney after acute kidney injury. This review article highlights the recent progress of the crosstalk between immune and metabolic systems in metabolic syndrome, with a focus on innate immune receptors.
    Keywords:  Crown-like structure; Fatty acids; Metabolic syndrome; Mincle; Obesity; TLR4
    DOI:  https://doi.org/10.1186/s41232-022-00198-7
  34. Diabetes. 2022 May 02. pii: db210972. [Epub ahead of print]
    Endothelial Prohibitin Mediates Bi-directional Long Chain Fatty Acid Transport in White and Brown Adipose Tissues.
    Zhanguo Gao, Alexes C Daquinag, Yongmei Yu, Mikhail G Kolonin.
      The function of Prohibitin-1 (PHB1) in adipocyte mitochondrial respiration, adaptive thermogenesis, and long chain fatty acid (LCFA) metabolism has been reported. While intracellular PHB1 expression is ubiquitous, cell surface PHB1 localization is selective for adipocytes and endothelial cells of adipose tissue. The importance of PHB1 in adipose endothelium has not been investigated and its vascular cell surface function has remained unclear. Here, we generated and analyzed mice with PHB1 knock-out specifically in endothelial cells (PHB1 EC-KO). Despite the lack of endothelial PHB1, mice developed normally and had normal vascularizatoin in both white adipose tissue (WAT) and brown adipose tissue (BAT). Tumor and ex vivo explant angiogenesis assays also have not detected a functional defect in PHB1 KO endothelium. No metabolic phenotype was observed in PHB1 EC-KO mice raised on regular diet. We show that both male and female PHB1 EC-KO mice have normal body composition and adaptive thermogenesis. However, PHB1 EC-KO mice displayed higher insulin sensitivity and increased glucose clearance when fed high fat diet. We demonstrate that the efficacy of long chain fatty acid (LCFA) deposition by adipocytes is decreased by PHB1 EC KO, in particular in brown adipose tissue (BAT). Consistent with that, EC-KO mice have a defect in clearing triglycerides from systemic circulation. Free fatty acid release upon lipolysis induction was also found to be reduced in PHB1 EC-KO mice. Our results demonstrate that PHB1 in endothelial cells regulates bi-directional LCFA transport and thereby suppresses glucose utilization.
    DOI:  https://doi.org/10.2337/db21-0972
  35. J Lipid Res. 2022 Apr 27. pii: S0022-2275(22)00052-9. [Epub ahead of print] 100219
    Deep-lipidotyping by mass spectrometry: recent technical advances and applications.
    Wenpeng Zhang, Ruijun Jian, Jing Zhao, Yikun Liu, Yu Xia.
      In-depth structural characterization of lipids is an essential component of lipidomics. There has been a rapid expansion of mass spectrometry methods that are capable of resolving lipid isomers at various structural levels over the past decade. These developments finally make deep-lipidotyping possible, which provides new means to study lipid metabolism and discover new lipid biomarkers. In this review, we discuss recent advancements in tandem mass spectrometry (MS/MS) methods for identification of complex lipids beyond the species (known headgroup information) and molecular species (known chain composition) levels. These include identification at the levels of carbon-carbon double bond (C=C) location and sn-position as well as characterization of acyl chain modifications. We also discuss the integration of isomer-resolving MS/MS methods with different lipid analysis workflows and their applications in lipidomics. The results showcase the distinct capabilities of deep-lipidotyping in untangling the metabolism of individual isomers and sensitive phenotyping by using relative fractional quantitation of the isomers.
    Keywords:  branched-chain fatty acids; double bond location; glycerolipids; glycerophospholipids; lipid isomers; lipidomics; liquid chromatography; phenotyping; sn-position; tandem mass spectrometry
    DOI:  https://doi.org/10.1016/j.jlr.2022.100219
  36. J Transl Med. 2022 May 04. 20(1): 197
    Single-cell N6-methyladenosine regulator patterns guide intercellular communication of tumor microenvironment that contribute to colorectal cancer progression and immunotherapy.
    Yuzhen Gao, Hao Wang, Shipeng Chen, Rui An, Yadong Chu, Guoli Li, Yanzhong Wang, Xinyou Xie, Jun Zhang.
       BACKGROUND: N6-methyladenosine (m6A) RNA methylation plays a critical role in key genetic events for various cancers; yet, how m6A functions within the tumor microenvironment (TME) remains to be elucidated.
    METHODS: A total of 65,362 single cells from single-cell RNA-seq data derived from 33 CRC tumor samples were analyzed by nonnegative matrix factorization (NMF) for 23 m6A RNA methylation regulators. CRC and Immunotherapy cohorts from public repository were used to determine the prognosis and immune response of TME clusters.
    RESULTS: The fibroblasts, macrophages, T and B cells were respectively grouped into 4 to 5 subclusters and then classified according to various biological processes and different marker genes. Furthermore, it revealed that the m6A RNA methylation regulators might be significantly related to the clinical and biological features of CRC, as well as the pseudotime trajectories of main TME cell types. Bulk-seq analysis suggested that these m6A-mediated TME cell subclusters had significant prognostic value for CRC patients and distinguished immune response for patients who underwent ICB therapy, especially for the CAFs and macrophages. Notably, CellChat analysis revealed that RNA m6A methylation-associated cell subtypes of TME cells manifested diverse and extensive interaction with tumor epithelial cells. Further analysis showed that ligand-receptor pairs, including MIF -  (CD74 + CXCR4), MIF -  (CD74 + CD44), MDK-NCL and LGALS9 - CD45, etc. mediated the communication between m6A associated subtypes of TME cells and tumor epithelial cells.
    CONCLUSIONS: Taken together, our study firstly revealed the m6A methylation mediated intercellular communication of the tumor microenvironment in the regulation of tumor growth and antitumor immunomodulatory processes.
    Keywords:  Colorectal cancer; Immunotherapy; Prognosis; Single-cell; Tumor microenvironment; m6A
    DOI:  https://doi.org/10.1186/s12967-022-03395-7
  37. Front Immunol. 2022 ;13 821480
    Pleural Resident Macrophages and Pleural IRA B Cells Promote Efficient Immunity Against Pneumonia by Inducing Early Pleural Space Inflammation.
    Alan Bénard, Malgorzata J Podolska, Franziska Czubayko, Isabella Kutschick, Bettina Klösch, Anne Jacobsen, Elisabeth Naschberger, Maximilian Brunner, Christian Krautz, Denis I Trufa, Horia Sirbu, Roland Lang, Robert Grützmann, Georg F Weber.
      Airway infection is a major cause of mortality worldwide. The identification of new mechanisms aiding in effective host immune response is therefore required. Here, we show that the specific depletion of the pleural immune cell compartment during bacterial pneumonia resulted in a reduced pulmonary immune response and increased mortality in mice. Bacterial airway infection provoked early pleural space (PS) inflammation characterized by innate response activator (IRA) B cell development and pleural large resident macrophage (LRM) necroptosis, the repopulation of LRMs being driven by cellular proliferation in situ. Necroptotic LRMs amplified PS inflammation by stimulating pleural Mincle-expressing macrophages whereas IRA B cells contributed partially to GM-CSF-induced PS inflammation. Upon pulmonary infection, the induction of PS inflammation resulted in reduced bacterial burden whereas the specific depletion of pleural resident macrophages led to increased mortality and bacterial burden and reduced pulmonary immunity. Moreover, mice in which B cells were unable to produce GM-CSF exhibited reduced CD103+ dendritic cells and reduced CD4+ T cell numbers in the draining lymph node. Altogether, our results describe a previously unrecognized mechanism of pleural space inflammation necessary for effective protection against bacterial airway infection.
    Keywords:  IRA B cells; bacterial airway infection; mincle; necroptosis; pleural resident macrophages; pleural space
    DOI:  https://doi.org/10.3389/fimmu.2022.821480
  38. Front Immunol. 2022 ;13 825207
    Splenic Dendritic Cells and Macrophages Drive B Cells to Adopt a Plasmablast Cell Fate.
    Hayley A McNamara, Mireille H Lahoud, Yeping Cai, Jessica Durrant-Whyte, James H O'Connor, Irina Caminschi, Ian A Cockburn.
      Upon encountering cognate antigen, B cells can differentiate into short-lived plasmablasts, early memory B cells or germinal center B cells. The factors that determine this fate decision are unclear. Past studies have addressed the role of B cell receptor affinity in this process, but the interplay with other cellular compartments for fate determination is less well understood. Moreover, B cell fate decisions have primarily been studied using model antigens rather than complex pathogen systems, which potentially ignore multifaceted interactions from other cells subsets during infection. Here we address this question using a Plasmodium infection model, examining the response of B cells specific for the immunodominant circumsporozoite protein (CSP). We show that B cell fate is determined in part by the organ environment in which priming occurs, with the majority of the CSP-specific B cell response being derived from splenic plasmablasts. This plasmablast response could occur independent of T cell help, though gamma-delta T cells were required to help with the early isotype switching from IgM to IgG. Interestingly, selective ablation of CD11c+ dendritic cells and macrophages significantly reduced the splenic plasmablast response in a manner independent of the presence of CD4 T cell help. Conversely, immunization approaches that targeted CSP-antigen to dendritic cells enhanced the magnitude of the plasmablast response. Altogether, these data indicate that the early CSP-specific response is predominately primed within the spleen and the plasmablast fate of CSP-specific B cells is driven by macrophages and CD11c+ dendritic cells.
    Keywords:  B cell; Plasmodium; T cell help; cell fate acquisition; circumsporozoite (CS) protein; dendritic cells; malaria; plasmablasts
    DOI:  https://doi.org/10.3389/fimmu.2022.825207
  39. J Biol Chem. 2022 Apr 29. pii: S0021-9258(22)00440-9. [Epub ahead of print] 102000
    Oxidized high-density lipoprotein promotes CD36 palmitoylation and increases lipid uptake in macrophages.
    Yun Zhang, Doudou Dong, Xiaoting Xu, Hui He, Yuan Zhu, Tingwen Lei, Hailong Ou.
      Oxidized high-density lipoprotein (oxHDL) reduces the ability of cells to mediate reverse cholesterol transport, and also shows atherogenic properties. Palmitoylation of CD36, an important receptor mediating lipoprotein uptake in macrophages, has been demonstrated to be a requirement for fatty acid endocytosis. However, the relationship between oxHDL and CD36 has not been described in mechanistic detail. Here, we demonstrate using acyl-biotin exchange analysis that oxHDL activates CD36 by increasing CD36 palmitoylation, which promotes efficient uptake in macrophages. This modification increased CD36 incorporation into plasma lipid rafts and activated downstream signaling mediators such as Lyn, Fyn, and JNK, which elicited enhanced oxHDL uptake and foam cell formation. Furthermore, blocking CD36 palmitoylation with the pharmacological inhibitor 2-bromopalmitate decreased cell surface translocation and lowered oxHDL uptake in oxHDL-treated macrophages. We verified these results by transfecting oxHDL-induced macrophages with vectors expressing wild-type or mutant CD36 in which the cytoplasmic palmitoylated cysteine residues were replaced. We show cells containing mutant CD36 exhibited less palmitoylated CD36, disrupted plasma membrane trafficking, and reduced protein stability. Moreover, in ApoE-/-CD36-/- mice, lipid accumulation at the aortic root in mice receiving the mutant CD36 vector was decreased, suggesting that CD36 palmitoylation is responsible for lipid uptake in vivo. Finally, our data indicated that palmitoylation of CD36 was dependent on DHHC6 acyltransferase and its cofactor selenoprotein K, which increased the CD36/caveolin-1 interaction and membrane targeting in cells exposed to oxHDL. Altogether, our study uncovers a causal link between oxHDL and CD36 palmitoylation and provides insight into foam cell formation and atherogenesis.
    Keywords:  CD36; DHHC6; lipid uptake; oxHDL; palmitoylation
    DOI:  https://doi.org/10.1016/j.jbc.2022.102000
  40. Food Funct. 2022 May 03.
    Metabolic regulation of (-)-epicatechin and the colonic metabolite 2,3-dihydroxybenzoic acid on the glucose uptake, lipid accumulation and insulin signalling in cardiac H9c2 cells.
    Esther García-Díez, María Elvira López-Oliva, Jara Pérez-Jiménez, María Angeles Martín, Sonia Ramos.
      Epicatechin (EC) and main colonic phenolic acids derived from flavonoid intake have been suggested to exert healthful effects, although their mechanism of action remains unknown. Heart damage is highly prevalent in metabolic diseases, and the failure of this organ is a major cause of death worldwide. In this study, the modulation of the energy metabolism and insulin signalling by the mentioned compounds in cardiac H9c2 cells was evaluated. Incubation of cells with EC (1-20 μM) and 2,3-dihydroxybenzoic acid (DHBA, 10 μM) reduced glucose uptake, and both compounds decreased lipid accumulation at concentrations higher than 0.5 μM. EC and DHBA also increased the tyrosine phosphorylated and total insulin receptor (IR) levels, and activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway in cardiac H9c2 cells. Interestingly, EC and DHBA did not modify glucose transporters (SGLT-1 and GLUT-1) levels, and increased GLUT-4 values. In addition, EC and DHBA decreased cluster of differentiation 36 (CD36) and fatty acid synthase (FAS) values, and enhanced carnitine palmitoyl transferase 1 (CPT1) and proliferator activated receptor α (PPARα) levels. By using specific inhibitors of AKT and 5'-AMP-activated protein kinase (AMPK), the participation of both proteins in EC- and DHBA-mediated regulation on glucose uptake and lipid accumulation was shown. Taken together, EC and DHBA modulate glucose uptake and lipid accumulation via AKT and AMPK, and reinforce the insulin signalling by activating key proteins of this pathway in H9c2 cells.
    DOI:  https://doi.org/10.1039/d2fo00182a
  41. Mol Cell Biol. 2022 May 02. e0052221
    Mechanism of Erastin-Induced Ferroptosis in MDA-MB-231 Human Breast Cancer Cells: Evidence for a Critical Role of Protein Disulfide Isomerase.
    Hongge Wang, Pan Wang, Bao Ting Zhu.
      Ferroptosis is a form of regulated cell death resulting predominantly from catastrophic accumulation of lipid reactive oxygen species (ROS). While the antioxidant systems that counter ferroptosis have been well characterized, the mechanism underlying ferroptosis-associated accumulation of lipid ROS remains unclear. In this study, we demonstrated that protein disulfide isomerase (PDI) is a novel mediator of ferroptosis, which is responsible for the accumulation of lipid ROS and ultimately ferroptosis in MDA-MB-231 human breast cancer cells. Treatment with erastin led to a significant increase in inducible nitric oxide synthase (iNOS)-mediated nitric oxide production, which contributes to the accumulation of the death-inducing cellular lipid ROS. Small interfering RNA (siRNA)-mediated PDI knockdown or pharmacological inhibition of PDI's isomerase activity with cystamine strongly suppressed iNOS dimerization and its catalytic activation, subsequently prevented lipid ROS accumulation, and conferred strong protection against erastin-induced ferroptosis. Remarkably, PDI knockdown in MDA-MB-231 cells also largely abrogated the protective effect of cystamine against erastin-induced ferroptotic cell death. Together, these experimental observations demonstrate a noncanonical role of PDI in ferroptosis, which may serve as a potential therapeutic target for ferroptosis-related diseases.
    Keywords:  cell death; ferroptosis; iNOS; lipid ROS; nitric oxide; protein disulfide isomerase
    DOI:  https://doi.org/10.1128/mcb.00522-21
  42. Stem Cell Reports. 2022 Apr 28. pii: S2213-6711(22)00195-3. [Epub ahead of print]
    Iron accumulation induces oxidative stress, while depressing inflammatory polarization in human iPSC-derived microglia.
    Boyd Kenkhuis, Michelle van Eekeren, David A Parfitt, Yavuz Ariyurek, Poulomi Banerjee, Josef Priller, Louise van der Weerd, Willeke M C van Roon-Mom.
      Iron accumulation in microglia has been observed in Alzheimer's disease and other neurodegenerative disorders and is thought to contribute to disease progression through various mechanisms, including neuroinflammation. To study this interaction, we treated human induced pluripotent stem cell-derived microglia (iPSC-MG) with iron, in combination with inflammatory stimuli such as interferon gamma (IFN-γ) and amyloid β. Both IFN-γ and iron treatment increased labile iron levels, but only iron treatment led to a consistent increase of ferritin levels, reflecting long-term iron storage. Therefore, in iPSC-MG, ferritin appeared to be regulated by iron revels rather than inflammation. Further investigation showed that while IFN-γ induced pro-inflammatory activation, iron treatment dampened both classic pro- and anti-inflammatory activation on a transcriptomic level. Notably, iron-loaded microglia showed strong upregulation of cellular stress response pathways, the NRF2 pathway, and other oxidative stress pathways. Functionally, iPSC-MG exhibited altered phagocytosis and impaired mitochondrial metabolism following iron treatment. Collectively, these data suggest that in MG, in contrast to current hypotheses, iron treatment does not result in pro-inflammatory activation, but rather dampens it and induces oxidative stress.
    Keywords:  induced pluripotent stem cells; iron; microglia; neurodegenerative diseases; neuroinflammation; oxidative stress
    DOI:  https://doi.org/10.1016/j.stemcr.2022.04.006
  43. Int J Gen Med. 2022 ;15 4465-4474
    Lactate Transporter SLC16A3 (MCT4) as an Onco-Immunological Biomarker Associating Tumor Microenvironment and Immune Responses in Lung Cancer.
    Qingsong Tao, Xin Li, Ting Zhu, Xiaoqin Ge, Shengping Gong, Jianxin Guo, Ruishuang Ma.
       Purpose: Lactate, a marker of tumor metabolic reprogramming, maintains the acidic microenvironment and also affects the metabolism and function of immune cells. SLC16A3 is responsible for the extracellular transport of lactate, which is a key component of glycolysis. However, the role of SLC16A3 in immune infiltration and immunosuppression of lung cancer is largely unknown. Our study explored the therapeutic and prognostic value of SLC16A3 in predicting immune infiltration and immune checkpoint efficacy of lung cancer.
    Methods: SLC16A3 expression was evaluated with TCGA database. Kaplan-Meier analysis was performed for survival rates. GO and KEEG enrichment was conducted to determine predictive signaling pathways. We utilized TIMER and CIBERSORT to analyze the correlation between SLC16A3 and immunocyte infiltration as well as immune checkpoint. Interleukin and HIF-1a expression was measured with ELISA kit and flow cytometry separately.
    Results: In comparison with normal tissues, SLC16A3 expression was significantly upregulated in both lung adenocarcinoma (LUAD) and squamous carcinoma (LUSC), which was closely related to poor prognosis. GO analysis indicated that SLC16A3 involved in different signal pathways in LUAD and LUSC and linked to HIF-1 signaling in LUAD. High SLC16A3 was correlated with immunosuppressive cells (Treg, Th2 and iDC), immune checkpoint (PD1, PD-L1, PVR, Tim-3, ITGAM) and immunosuppressive factors (foxp3, TGF-β) in LUAD not LUSC. Furthermore, SLC16A3 was identified to tightly interact with IL-8 which may induce microenvironment immune tolerance. Based on the clinical prediction, we performed experiments with LUAD A549 cells and showed reduced IL-8 and HIF-1a when treated with SLC16A3 knockdown. HIF-1a stimulation by dimethyloxalylglycine (DMOG) could restore IL-8 secretion in SLC16A3 downregulated cells.
    Conclusion: Taken together, our results suggest that SLC16A3 contributes to a worse prognosis in lung cancer and may play an important role in immune microenvironment and evasion through HIF-1a-IL8 axis, which could be a novel therapeutic target for immunotherapy in lung cancer.
    Keywords:  IL-8; SLC16A3 (MCT4); bioinformatics analysis; immune evasion; lung cancer
    DOI:  https://doi.org/10.2147/IJGM.S353592
  44. iScience. 2022 May 20. 25(5): 104241
    Microbiota-mediated skewing of tryptophan catabolism modulates CD4+ T cells in lupus-prone mice.
    Josephine Brown, Georges Abboud, Longhuan Ma, Seung-Chul Choi, Nathalie Kanda, Leilani Zeumer-Spataro, Jean Lee, Weidan Peng, Joy Cagmat, Tamas Faludi, Mansour Mohamadzadeh, Timothy Garrett, Laura Mandik-Nayak, Alexander Chervonsky, Andras Perl, Laurence Morel.
      A skewed tryptophan metabolism has been reported in patients with lupus. Here, we investigated the mechanisms by which it occurs in lupus-susceptible mice, and how tryptophan metabolites exacerbate T cell activation. Metabolomic analyses demonstrated that tryptophan is differentially catabolized in lupus mice compared to controls and that the microbiota played a role in this skewing. There was no evidence for differential expression of tryptophan catabolic enzymes in lupus mice, further supporting a major contribution of the microbiota to skewing. However, isolated lupus T cells processed tryptophan differently, suggesting a contribution of T cell intrinsic factors. Functionally, tryptophan and its microbial product tryptamine increased T cell metabolism and mTOR activation, while kynurenine promoted interferon gamma production, all of which have been associated with lupus. These results showed that a combination of microbial and T cell intrinsic factors promotes the production of tryptophan metabolites that enhance inflammatory phenotypes in lupus T cells.
    Keywords:  Biological sciences; Cell biology; Human metabolism; Immunology
    DOI:  https://doi.org/10.1016/j.isci.2022.104241
  45. Biochem Biophys Res Commun. 2022 Apr 15. pii: S0006-291X(22)00582-4. [Epub ahead of print]612 30-36
    The functional role of OGDH for maintaining mitochondrial respiration and identity of primed human embryonic stem cells.
    Yujie Liu, Han Wang, Min Shao, Ying Jin, Bing Liao.
      Human embryonic stem cells (hESCs) can self-renew infinitely and differentiate into the cell types of all lineages of our body, holding great promise for investigating early human embryo development and providing functional cells for disease treatment. For the full application of hESCs, it is necessary to elucidate how hESCs maintain their identity. Recent studies have shown that glycolysis and mitochondrial respiration are linked to pluripotency states. However, the function of mitochondrial respiration in hESCs has not been fully understood. Herein, we report that the adenosine triphosphate (ATP) production rate is comparable between mitochondrial respiration and glycolysis, suggesting an important contribution of mitochondrial respiration to ATP production in conventionally cultured hESCs. To investigate the function of mitochondrial respiration, we silence OGDH expression in hESCs by the inducible CRISPRi method, and find that OGDH knockdown (KD) results in disrupted TCA (tricarboxylic acid) cycle, and diminished mitochondrial respiration activity and total ATP level. Moreover, OGDH KD leads to hESC death and aberrant transcriptional program. Interestingly, blockage of the electron transport chain (ETC) by small molecule inhibitors gives rise to the phenotype similar to that observed in OGDH deficient hESCs. Therefore, genetic and pharmacological perturbations of the mitochondrial respiration impair identity of hESCs. Collectively, our study highlights the pivotal role of the mitochondrial respiration activity for the stemness maintenance of primed hESCs, and unveils OGDH as a key regulator for the proper production of ATP and TCA cycle metabolites in primed hESCs.
    Keywords:  ATP production; Human embryonic stem cells; Mitochondrial respiration; OGDH; Primed pluripotency
    DOI:  https://doi.org/10.1016/j.bbrc.2022.04.059
  46. J Nanobiotechnology. 2022 May 06. 20(1): 213
    ROS-responsive liposomes as an inhaled drug delivery nanoplatform for idiopathic pulmonary fibrosis treatment via Nrf2 signaling.
    Junzhao Liu, Zuohong Wu, Yadong Liu, Zhu Zhan, Liping Yang, Can Wang, Qinqin Jiang, Haitao Ran, Pan Li, Zhigang Wang.
       BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic disease with pathophysiological characteristics of transforming growth factor-β (TGF-β), and reactive oxygen species (ROS)-induced excessive fibroblast-to-myofibroblast transition and extracellular matrix deposition. Macrophages are closely involved in the development of fibrosis. Nuclear factor erythroid 2 related factor 2 (Nrf2) is a key molecule regulating ROS and TGF-β expression. Therefore, Nrf2 signaling modulation might be a promising therapy for fibrosis. The inhalation-based drug delivery can reduce systemic side effects and improve therapeutic effects, and is currently receiving increasing attention, but direct inhaled drugs are easily cleared and difficult to exert their efficacy. Therefore, we aimed to design a ROS-responsive liposome for the Nrf2 agonist dimethyl fumarate (DMF) delivery in the fibrotic lung. Moreover, we explored its therapeutic effect on pulmonary fibrosis and macrophage activation.
    RESULTS: We synthesized DMF-loaded ROS-responsive DSPE-TK-PEG@DMF liposomes (DTP@DMF NPs). DTP@DMF NPs had suitable size and negative zeta potential and excellent capability to rapidly release DMF in a high-ROS environment. We found that macrophage accumulation and polarization were closely related to fibrosis development, while DTP@DMF NPs could attenuate macrophage activity and fibrosis in mice. RAW264.7 and NIH-3T3 cells coculture revealed that DTP@DMF NPs could promote Nrf2 and downstream heme oxygenase-1 (HO-1) expression and suppress TGF-β and ROS production in macrophages, thereby reducing fibroblast-to-myofibroblast transition and collagen production by NIH-3T3 cells. In vivo experiments confirmed the above findings. Compared with direct DMF instillation, DTP@DMF NPs treatment presented enhanced antifibrotic effect. DTP@DMF NPs also had a prolonged residence time in the lung as well as excellent biocompatibility.
    CONCLUSIONS: DTP@DMF NPs can reduce macrophage-mediated fibroblast-to-myofibroblast transition and extracellular matrix deposition to attenuate lung fibrosis by upregulating Nrf2 signaling. This ROS-responsive liposome is clinically promising as an ideal delivery system for inhaled drug delivery.
    Keywords:  Dimethyl fumarate; Idiopathic pulmonary fibrosis; Inhaled drug delivery; Nrf2; ROS-responsive liposome
    DOI:  https://doi.org/10.1186/s12951-022-01435-4
  47. Biochem Biophys Res Commun. 2022 Apr 19. pii: S0006-291X(22)00600-3. [Epub ahead of print]612 22-29
    Carnosine synthase deficiency in mice affects protein metabolism in skeletal muscle.
    Jiawei Wu, Ai Egusa, Toshihide Nishimura.
      Carnosine and anserine are abundant peptides found in the skeletal muscle and nervous system in many vertebrates. Several in vitro and in vivo studies have demonstrate that exogenously administered carnosine improves exercise performance. Furthermore, carnosine is an antioxidant and antifatigue supplement. However, the physiological functions of endogenous carnosine and its related histidine-containing dipeptides in a living organism remain unclear. We aimed to clarify the physiological roles of endogenous carnosine by investigating the characteristics of carnosine synthase gene-deficient mice and the effects of carnosine on skeletal muscle protein metabolism. We discovered that carnosine and anserine were undetectable in the skeletal muscle of carnosine synthase knockout mice. We also quantified protein gene expression and enzyme levels in muscle protein metabolism. Gene and protein levels of the muscle protein synthesizer insulin-like growth factor-1 (IGF-1) and the degrading enzyme cathepsin B were markedly lower in carnosine synthase gene-deficient mice than those in wild-type mice. The amount of 3-methylhistidine (a marker for muscle proteolysis) in forced exercise and the weight of the gastrocnemius muscle were considerably lower in carnosine synthase gene-deficient mice than in wild-type mice. Consequently, we showed that carnosine deficiency affects weight maintenance and protein metabolism in skeletal muscle, suggesting that carnosine regulates skeletal muscle protein metabolism.
    Keywords:  Anserine; Carnosine; Knockout mice; Skeletal muscle metabolism
    DOI:  https://doi.org/10.1016/j.bbrc.2022.04.075
  48. Cell Rep. 2022 05 03. pii: S2211-1247(22)00514-9. [Epub ahead of print]39(5): 110750
    SM22α-lineage niche cells regulate intramembranous bone regeneration via PDGFRβ-triggered hydrogen sulfide production.
    Xueman Zhou, Jin Liu, Yingcheng Zheng, Zhenzhen Zhang, Yange Wu, Wenke Yang, Jiaqi Liu, Yanmei Huang, Yating Yi, Zhihe Zhao, Hengyi Xiao, Xianming Mo, Jun Wang.
      Bone stromal cells are critical for bone homeostasis and regeneration. Growing evidence suggests that non-stem bone niche cells support bone homeostasis and regeneration via paracrine mechanisms, which remain to be elucidated. Here, we show that physiologically quiescent SM22α-lineage stromal cells expand after bone injury to regulate diverse processes of intramembranous bone regeneration. The majority of SM22α-lineage cells neither act as stem cells in vivo nor show their expression patterns. Dysfunction of SM22α-lineage niche cells induced by loss of platelet-derived growth factor receptor β (PDGFRβ) impairs bone repair. We further show that PDGFRβ-triggered hydrogen sulfide (H2S) generation in SM22α-lineage niche cells facilitates osteogenesis and angiogenesis and suppresses overactive osteoclastogenesis. Collectively, these data demonstrate that non-stem SM22α-lineage niche cells support the niche for bone regeneration with a PDGFRβ/H2S-dependent regulatory mechanism. Our findings provide further insight into non-stem bone stromal niche cell populations and niche-regulation strategy for bone repair.
    Keywords:  CP: Cell biology; H(2)S; PDGFRβ; SM22α; bone regeneration niche; hydrogen sulfide; niche cell; platelet-derived growth factor receptors β
    DOI:  https://doi.org/10.1016/j.celrep.2022.110750
  49. Front Immunol. 2022 ;13 789366
    Acidic Microenvironments Found in Cutaneous Leishmania Lesions Curtail NO-Dependent Antiparasitic Macrophage Activity.
    Linus Frick, Linda Hinterland, Kathrin Renner, Marion Vogl, Nathalie Babl, Simon Heckscher, Anna Weigert, Susanne Weiß, Joachim Gläsner, Raffaela Berger, Peter J Oefner, Katja Dettmer, Marina Kreutz, Valentin Schatz, Jonathan Jantsch.
      Local tissue acidosis affects anti-tumor immunity. In contrast, data on tissue pH levels in infected tissues and their impact on antimicrobial activity is sparse. In this study, we assessed the pH levels in cutaneous Leishmania lesions. Leishmania major-infected skin tissue displayed pH levels of 6.7 indicating that lesional pH is acidic. Next, we tested the effect of low extracellular pH on the ability of macrophages to produce leishmanicidal NO and to fight the protozoan parasite Leishmania major. Extracellular acidification led to a marked decrease in both NO production and leishmanicidal activity of lipopolysaccharide (LPS) and interferon γ (IFN-γ)-coactivated macrophages. This was not directly caused by a disruption of NOS2 expression, a shortage of reducing equivalents (NAPDH) or substrate (L-arginine), but by a direct, pH-mediated inhibition of NOS2 enzyme activity. Normalization of intracellular pH significantly increased NO production and antiparasitic activity of macrophages even in an acidic microenvironment. Overall, these findings indicate that low local tissue pH can curtail NO production and leishmanicidal activity of macrophages.
    Keywords:  Leishmania; NO; NOS2; macrophages; pH
    DOI:  https://doi.org/10.3389/fimmu.2022.789366
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