bims-imicid Biomed News
on Immunometabolism of infection, cancer and immune-mediated disease
Issue of 2022–03–20
fiveteen papers selected by
Dylan Ryan, University of Cambridge
  1. Human gut bacteria produce ΤΗ17-modulating bile acid metabolites.
  2. Metabolic adaptation of ovarian tumors in patients treated with an IDO1 inhibitor constrains antitumor immune responses.
  3. Triglyceride breakdown from lipid droplets regulates the inflammatory response in macrophages.
  4. Dihydronicotinamide Riboside Is a Potent NAD+ Precursor Promoting a Pro-Inflammatory Phenotype in Macrophages.
  5. ScRNA-seq identified the metabolic reprogramming of human colonic immune cells in different locations and disease states.
  6. Sirtuins are crucial regulators of T cell metabolism and functions.
  7. The Role of T Cells in Obesity-Associated Inflammation and Metabolic Disease.
  8. Clinically relevant T cell expansion media activate distinct metabolic programs uncoupled from cellular function.
  9. IL-4 polarized human macrophage exosomes control cardiometabolic inflammation & diabetes in obesity.
  10. Targeting Glycolysis in Alloreactive T Cells to Prevent Acute Graft-Versus-Host Disease While Preserving Graft-Versus-Leukemia Effect.
  11. Improving Cancer Immunotherapy: Exploring and Targeting Metabolism in Hypoxia Microenvironment.
  12. Metabolism Characteristics of Th17 and Regulatory T Cells in Autoimmune Diseases.
  13. Reprogramming of red blood cell metabolism in Zika virus-infected donors.
  14. A urinary proteomic landscape of COVID-19 progression identifies signaling pathways and therapeutic options.
  15. Amelioration of Endotoxemia by a Synthetic Analog of Omega-3 Epoxyeicosanoids.
  1. Nature. 2022 Mar 16.
    Human gut bacteria produce ΤΗ17-modulating bile acid metabolites.
    Donggi Paik, Lina Yao, Yancong Zhang, Sena Bae, Gabriel D D'Agostino, Minghao Zhang, Eunha Kim, Eric A Franzosa, Julian Avila-Pacheco, Jordan E Bisanz, Christopher K Rakowski, Hera Vlamakis, Ramnik J Xavier, Peter J Turnbaugh, Randy S Longman, Michael R Krout, Clary B Clish, Fraydoon Rastinejad, Curtis Huttenhower, Jun R Huh, A Sloan Devlin.
      The microbiota modulates gut immune homeostasis. Bacteria influence the development and function of host immune cells, including T helper cells expressing interleukin-17A (TH17 cells). We previously reported that the bile acid metabolite 3-oxolithocholic acid (3-oxoLCA) inhibits TH17 cell differentiation1. Although it was suggested that gut-residing bacteria produce 3-oxoLCA, the identity of such bacteria was unknown, and it was unclear whether 3-oxoLCA and other immunomodulatory bile acids are associated with inflammatory pathologies in humans. Here we identify human gut bacteria and corresponding enzymes that convert the secondary bile acid lithocholic acid into 3-oxoLCA as well as the abundant gut metabolite isolithocholic acid (isoLCA). Similar to 3-oxoLCA, isoLCA suppressed TH17 cell differentiation by inhibiting retinoic acid receptor-related orphan nuclear receptor-γt, a key TH17-cell-promoting transcription factor. The levels of both 3-oxoLCA and isoLCA and the 3α-hydroxysteroid dehydrogenase genes that are required for their biosynthesis were significantly reduced in patients with inflammatory bowel disease. Moreover, the levels of these bile acids were inversely correlated with the expression of TH17-cell-associated genes. Overall, our data suggest that bacterially produced bile acids inhibit TH17 cell function, an activity that may be relevant to the pathophysiology of inflammatory disorders such as inflammatory bowel disease.
    DOI:  https://doi.org/10.1038/s41586-022-04480-z
  2. Sci Transl Med. 2022 Mar 16. 14(636): eabg8402
    Metabolic adaptation of ovarian tumors in patients treated with an IDO1 inhibitor constrains antitumor immune responses.
    Kunle Odunsi, Feng Qian, Amit A Lugade, Han Yu, Melissa A Geller, Steven P Fling, Judith C Kaiser, Andreanne M Lacroix, Leonard D'Amico, Nirasha Ramchurren, Chihiro Morishima, Mary L Disis, Lucas Dennis, Patrick Danaher, Sarah Warren, Van Anh Nguyen, Sudharshan Ravi, Takemasa Tsuji, Spencer Rosario, Wenjuan Zha, Alan Hutson, Song Liu, Shashikant Lele, Emese Zsiros, A J Robert McGray, Jessie Chiello, Richard Koya, Thinle Chodon, Carl D Morrison, Vasanta Putluri, Nagireddy Putluri, Donald E Mager, Rudiyanto Gunawan, Martin A Cheever, Sebastiano Battaglia, Junko Matsuzaki.
      To uncover underlying mechanisms associated with failure of indoleamine 2,3-dioxygenase 1 (IDO1) blockade in clinical trials, we conducted a pilot, window-of-opportunity clinical study in 17 patients with newly diagnosed advanced high-grade serous ovarian cancer before their standard tumor debulking surgery. Patients were treated with the IDO1 inhibitor epacadostat, and immunologic, transcriptomic, and metabolomic characterization of the tumor microenvironment was undertaken in baseline and posttreatment tumor biopsies. IDO1 inhibition resulted in efficient blockade of the kynurenine pathway of tryptophan degradation and was accompanied by a metabolic adaptation that shunted tryptophan catabolism toward the serotonin pathway. This resulted in elevated nicotinamide adenine dinucleotide (NAD+), which reduced T cell proliferation and function. Because NAD+ metabolites could be ligands for purinergic receptors, we investigated the impact of blocking purinergic receptors in the presence or absence of NAD+ on T cell proliferation and function in our mouse model. We demonstrated that A2a and A2b purinergic receptor antagonists, SCH58261 or PSB1115, respectively, rescued NAD+-mediated suppression of T cell proliferation and function. Combining IDO1 inhibition and A2a/A2b receptor blockade improved survival and boosted the antitumor immune signature in mice with IDO1 overexpressing ovarian cancer. These findings elucidate the downstream adaptive metabolic consequences of IDO1 blockade in ovarian cancers that may undermine antitumor T cell responses in the tumor microenvironment.
    DOI:  https://doi.org/10.1126/scitranslmed.abg8402
  3. Proc Natl Acad Sci U S A. 2022 Mar 22. 119(12): e2114739119
    Triglyceride breakdown from lipid droplets regulates the inflammatory response in macrophages.
    Xanthe A M H van Dierendonck, Frank Vrieling, Lisa Smeehuijzen, Lei Deng, Joline P Boogaard, Cresci-Anne Croes, Lieve Temmerman, Suzan Wetzels, Erik Biessen, Sander Kersten, Rinke Stienstra.
      SignificanceLipid droplets (LDs) are ubiquitous organelles that play important roles in cellular energy homeostasis, tightly regulating the accumulation and release of lipids. In macrophages, lipids accumulate in LDs during inflammation. However, it is unclear how inflammatory activation promotes the accumulation of lipids in LDs, and how the dynamic between lipid accumulation and breakdown could drive or inhibit inflammation. Elucidating the role of lipid accumulation during inflammation may provide important knowledge to influence inflammatory processes during health and disease. We identify the importance of the hypoxia-inducible lipid droplet-associated protein and the intracellular adipose triglyceride lipase in the regulation of lipid accumulation and breakdown in inflammatory macrophages. Furthermore, we determine the regulatory effect of lipid breakdown from LDs in supporting inflammation.
    Keywords:  ATGL; HILPDA; immunometabolism; lipid droplets; macrophages
    DOI:  https://doi.org/10.1073/pnas.2114739119
  4. Front Immunol. 2022 ;13 840246
    Dihydronicotinamide Riboside Is a Potent NAD+ Precursor Promoting a Pro-Inflammatory Phenotype in Macrophages.
    Claudia C S Chini, Thais R Peclat, Lilian S Gomez, Julianna D Zeidler, Gina M Warner, Sonu Kashyap, Delaram Z Mazdeh, Faisal Hayat, Marie E Migaud, Aneel Paulus, Asher A Chanan-Khan, Eduardo N Chini.
      Nicotinamide adenine dinucleotide (NAD) metabolism plays an important role in the regulation of immune function. However, a complete picture of how NAD, its metabolites, precursors, and metabolizing enzymes work together in regulating immune function and inflammatory diseases is still not fully understood. Surprisingly, few studies have compared the effect of different forms of vitamin B3 on cellular functions. Therefore, we investigated the role of NAD boosting in the regulation of macrophage activation and function using different NAD precursors supplementation. We compared nicotinamide mononucleotide (NMN), nicotinamide riboside (NR), and nicotinamide (NAM) supplementation, with the recently described potent NAD precursor NRH. Our results show that only NRH supplementation strongly increased NAD+ levels in both bone marrow-derived and THP-1 macrophages. Importantly, NRH supplementation activated a pro-inflammatory phenotype in resting macrophages, inducing gene expression of several cytokines, chemokines, and enzymes. NRH also potentiated the effect of lipopolysaccharide (LPS) on macrophage activation and cytokine gene expression, suggesting that potent NAD+ precursors can promote inflammation in macrophages. The effect of NRH in NAD+ boosting and gene expression was blocked by inhibitors of adenosine kinase, equilibrative nucleoside transporters (ENT), and IκB kinase (IKK). Interestingly, the IKK inhibitor, BMS-345541, blocked the mRNA expression of several enzymes and transporters involved in the NAD boosting effect of NRH, indicating that IKK is also a regulator of NAD metabolism. In conclusion, NAD precursors such as NRH may be important tools to understand the role of NAD and NADH metabolism in the inflammatory process of other immune cells, and to reprogram immune cells to a pro-inflammatory phenotype, such as the M2 to M1 switch in macrophage reprogramming, in the cancer microenvironment.
    Keywords:  NAD; NRH; gene expression; inflammatory; macrophages
    DOI:  https://doi.org/10.3389/fimmu.2022.840246
  5. Biochem Biophys Res Commun. 2022 Mar 10. pii: S0006-291X(22)00359-X. [Epub ahead of print]604 96-103
    ScRNA-seq identified the metabolic reprogramming of human colonic immune cells in different locations and disease states.
    Qiuchen Zhao, Tong Zhang, Hao Yang.
      Different regions and states of the human colon are likely to have a distinct influence on immune cell functions. Here we studied the immunometabolic mechanisms for spatial immune specialization and dysregulated immune response during ulcerative colitis at single-cell resolution. We revealed that the macrophages and CD8+ T cells in the lamina propria of the human colon possessed an effector phenotype and were more activated, while their lipid metabolism was suppressed compared with those in the epithelial. Also, IgA+ plasma cells accumulated in lamina propria of the sigmoid colon were identified to be more metabolically activated versus those in the cecum and transverse colon, and the improved metabolic activity was correlated with the expression of CD27. In addition to the immunometabolic reprogramming caused by spatial localization colon, we found dysregulated cellular metabolism was related to the impaired immune functions of macrophages and dendritic cells in patients with ulcerative colitis. The cluster of OSM+ inflammatory monocytes was also identified to play its role in resistance to anti-TNF treatment, and we explored targeted metabolic reactions that could reprogram them to a normal state. Altogether, this study revealed a landscape of metabolic reprogramming of human colonic immune cells in different locations and disease states, and offered new insights into treating ulcerative colitis by immunometabolic modulation.
    Keywords:  Anti-TNF therapy Resistance; Human colon; Immunometabolic modulation; Inflammation; Single-cell immunometabolism; Spatial immune specialization; Ulcerative colitis
    DOI:  https://doi.org/10.1016/j.bbrc.2022.03.034
  6. Exp Mol Med. 2022 Mar 16.
    Sirtuins are crucial regulators of T cell metabolism and functions.
    Imene Hamaidi, Sungjune Kim.
      It is well known that metabolism underlies T cell differentiation and functions. The pathways regulating T cell metabolism and function are interconnected, and changes in T cell metabolic activity directly impact the effector functions and fate of T cells. Thus, understanding how metabolic pathways influence immune responses and ultimately affect disease progression is paramount. Epigenetic and posttranslational modification mechanisms have been found to control immune responses and metabolic reprogramming. Sirtuins are NAD+-dependent histone deacetylases that play key roles during cellular responses to a variety of stresses and have recently been reported to have potential roles in immune responses. Therefore, sirtuins are of significant interest as therapeutic targets to treat immune-related diseases and enhance antitumor immunity. This review aims to illustrate the potential roles of sirtuins in different subtypes of T cells during the adaptive immune response.
    DOI:  https://doi.org/10.1038/s12276-022-00739-7
  7. Immune Netw. 2022 Feb;22(1): e13
    The Role of T Cells in Obesity-Associated Inflammation and Metabolic Disease.
    Chan-Su Park, Nilabh Shastri.
      Chronic inflammation plays a critical role in the development of obesity-associated metabolic disorders such as insulin resistance. Obesity alters the microenvironment of adipose tissue and the intestines from anti-inflammatory to pro-inflammatory, which promotes low grade systemic inflammation and insulin resistance in obese mice. Various T cell subsets either help maintain metabolic homeostasis in healthy states or contribute to obesity-associated metabolic syndromes. In this review, we will discuss the T cell subsets that reside in adipose tissue and intestines and their role in the development of obesity-induced systemic inflammation.
    Keywords:  Insulin resistance; Metabolic diseases; Obese mice; Obesity-associated inflammation; T cells
    DOI:  https://doi.org/10.4110/in.2022.22.e13
  8. Mol Ther Methods Clin Dev. 2022 Mar 10. 24 380-393
    Clinically relevant T cell expansion media activate distinct metabolic programs uncoupled from cellular function.
    Sarah MacPherson, Sarah Keyes, Marisa K Kilgour, Julian Smazynski, Vanessa Chan, Jessica Sudderth, Tim Turcotte, Adria Devlieger, Jessie Yu, Kimberly S Huggler, Jason R Cantor, Ralph J DeBerardinis, Christopher Siatskas, Julian J Lum.
      Ex vivo expansion conditions used to generate T cells for immunotherapy are thought to adopt metabolic phenotypes that impede therapeutic efficacy in vivo. The comparison of five different culture media used for clinical T cell expansion revealed unique optima based on different output variables, including proliferation, differentiation, function, activation, and mitochondrial phenotypes. The extent of proliferation and function depended on the culture media rather than stimulation conditions. Moreover, the expanded T cell end products adapted their metabolism when switched to a different media formulation, as shown by glucose and glutamine uptake and patterns of glucose isotope labeling. However, adoption of these metabolic phenotypes was uncoupled to T cell function. Expanded T cell products cultured in ascites from ovarian cancer patients displayed suppressed mitochondrial activity and function irrespective of the ex vivo expansion media. Thus, ex vivo T cell expansion media have profound impacts on metabolism and function.
    Keywords:  13C tracer analysis; T cell expansion; cell-based immunotherapy; culture media; metabolism; phenotype
    DOI:  https://doi.org/10.1016/j.omtm.2022.02.004
  9. Mol Ther. 2022 Mar 12. pii: S1525-0016(22)00165-4. [Epub ahead of print]
    IL-4 polarized human macrophage exosomes control cardiometabolic inflammation & diabetes in obesity.
    Tuan Anh Phu, Martin Ng, Ngan K Vu, Laura Bouchareychas, Robert L Raffai.
      Cardiometabolic disease is an increasing cause of morbidity and death in society. While M1-like macrophages contribute to metabolic inflammation and insulin resistance, those polarized to an M2-like phenotype exert protective properties. Building on our observations reporting M2-like macrophage exosomes in atherosclerosis control, we tested whether they could serve to control inflammation in the liver and adipose tissue of obese mice. In thinking of clinical translation, we studied human THP-1 macrophages exposed to IL-4 as a source of exosomes (THP1-IL4-exo). Our findings show that THP1-IL4-exo polarized primary macrophages to an anti-inflammatory phenotype and reprogramed their energy metabolism by increasing levels of miR-21/99a/146b/378a while reducing miR-33. This increased lipophagy, mitochondrial activity, and oxidative phosphorylation (OXPHOS). THP1-IL4-exo exerted a similar regulation of these microRNAs in cultured 3T3-L1 adipocytes. This enhanced insulin-dependent glucose uptake through increased PPARγ-driven expression of GLUT4. It also increased levels of UCP1 and OXPHOS activity that promoted lipophagy, mitochondrial activity, and beiging of 3T3-L1 adipocytes. Intraperitoneal infusions of THP1-IL4-exo into obese wildtype and Ldlr-/- mice fed a Western high-fat diet reduced hematopoiesis and myelopoiesis, and favorably reprogramed inflammatory signaling and metabolism in circulating Ly6Chi monocytes. This also reduced leukocyte numbers and inflammatory activity in the circulation, aorta, adipose tissue and the liver. Such treatments reduced hepatic steatosis and increased the beiging of white adipose tissue as revealed by increased UCP1 expression and OXPHOS activity that normalized blood insulin levels and improved glucose tolerance. Our findings support THP1-IL4-exo as a therapeutic approach to control cardiometabolic disease and diabetes in obesity.
    DOI:  https://doi.org/10.1016/j.ymthe.2022.03.008
  10. Front Immunol. 2022 ;13 751296
    Targeting Glycolysis in Alloreactive T Cells to Prevent Acute Graft-Versus-Host Disease While Preserving Graft-Versus-Leukemia Effect.
    Ying Huang, Yujing Zou, Yiqun Jiao, Peijie Shi, Xiaoli Nie, Wei Huang, Chuanfeng Xiong, Michael Choi, Charles Huang, Andrew N Macintyre, Amanda Nichols, Fang Li, Chuan-Yuan Li, Nancie J MacIver, Diana M Cardona, Todd V Brennan, Zhiguo Li, Nelson J Chao, Jeffrey C Rathmell, Benny J Chen.
      Alloreactive donor T cells undergo extensive metabolic reprogramming to become activated and induce graft-versus-host disease (GVHD) upon alloantigen encounter. It is generally thought that glycolysis, which promotes T cell growth and clonal expansion, is employed in this process. However, conflicting data have been reported regarding the requirement of glycolysis to induce T cell-mediated GVHD due to the lack of T cell-specific treatments using glycolysis inhibitors. Importantly, previous studies have not evaluated whether graft-versus-leukemia (GVL) activity is preserved in donor T cells deficient for glycolysis. As a critical component affecting the clinical outcome, it is necessary to assess the anti-tumor activity following treatment with metabolic modulators in preclinical models. In the present study, we utilized T cells selectively deficient for glucose transporter 1 (Glut1T-KO), to examine the role of glycolysis exclusively in alloreactive T cells without off-targeting effects from antigen presenting cells and other cell types that are dependent on glycolysis. We demonstrated that transfer of Glut1T-KO T cells significantly improved acute GVHD outcomes through increased apoptotic rates, impaired expansion, and decreased proinflammatory cytokine production. In addition to impaired GVHD development, donor Glut1T-KO T cells mediated sufficient GVL activity to protect recipients from tumor development. A clinically relevant approach using donor T cells treated with a small molecule inhibitor of glycolysis, 2-Deoxy-D-glucose ex vivo, further demonstrated protection from tumor development. These findings indicate that treatment with glycolysis inhibitors prior to transplantation selectively eliminates alloreactive T cells, but spares non-alloreactive T cells including those that protect against tumor growth. The present study has established a definitive role for glycolysis in acute GVHD and demonstrated that acute GVHD can be selectively prevented through targeting glycolysis.
    Keywords:  GVL effects; GvHD; T cells; allogeneic hematopoietic cell transplantation; glycolysis; metabolism
    DOI:  https://doi.org/10.3389/fimmu.2022.751296
  11. Front Immunol. 2022 ;13 845923
    Improving Cancer Immunotherapy: Exploring and Targeting Metabolism in Hypoxia Microenvironment.
    Jinfen Wei, Meiling Hu, Hongli Du.
      Although immunotherapy has achieved good results in various cancer types, a large proportion of patients are limited from the benefits. Hypoxia and metabolic reprogramming are the common and critical factors that impact immunotherapy response. Here, we present current research on the metabolism reprogramming induced by hypoxia on antitumor immunity and discuss the recent progression among preclinical and clinical trials exploring the therapeutic effects combining targeting hypoxia and metabolism with immunotherapy. By evaluating the little clinical translation of the combined therapy, we provide insight into "understanding and regulating cellular metabolic plasticity under the current tumor microenvironment (TME)," which is essential to explore the strategy for boosting immune responses by targeting the metabolism of tumor cells leading to harsh TMEs. Therefore, we highlight the potential value of advanced single-cell technology in revealing the metabolic heterogeneity and corresponding phenotype of each cell subtype in the current hypoxic lesion from the clinical patients, which can uncover potential metabolic targets and therapeutic windows to enhance immunotherapy.
    Keywords:  cancer immunotherapy; cell subtypes; hypoxia; metabolic reprogramming; single-cell analysis
    DOI:  https://doi.org/10.3389/fimmu.2022.845923
  12. Front Immunol. 2022 ;13 828191
    Metabolism Characteristics of Th17 and Regulatory T Cells in Autoimmune Diseases.
    Yan Qin, Chong Gao, Jing Luo.
      The abnormal number and functional deficiency of immune cells are the pathological basis of various diseases. Recent years, the imbalance of Th17/regulatory T (Treg) cell underlies the occurrence and development of inflammation in autoimmune diseases (AID). Currently, studies have shown that material and energy metabolism is essential for maintaining cell survival and normal functions and the altered metabolic state of immune cells exists in a variety of AID. This review summarizes the biology and functions of Th17 and Treg cells in AID, with emphasis on the advances of the roles and regulatory mechanisms of energy metabolism in activation, differentiation and physiological function of Th17 and Treg cells, which will facilitate to provide targets for the treatment of immune-mediated diseases.
    Keywords:  Th17 cells; autoimmune disease; gut microbiota; immunometabolism; regulatory T cells; single-cell metabolism
    DOI:  https://doi.org/10.3389/fimmu.2022.828191
  13. Transfusion. 2022 Mar 14.
    Reprogramming of red blood cell metabolism in Zika virus-infected donors.
    Alexis Catala, Mars Stone, Michael P Busch, Angelo D'Alessandro.
       BACKGROUND: Diseases caused by arthropod-borne viruses remain a burden to global health; in particular, Zika virus (ZIKV) has been reported in 87 countries and territories. In healthy blood donors, ZIKV RNA can be detected in red blood cells (RBCs) months after infection, clearance of detectable nucleic acid in plasma, and seroconversion. However, little information is available on the impact of ZIKV infection to metabolism.
    STUDY DESIGN AND METHODS: We applied mass spectrometry-based metabolomics and lipidomics approaches to investigate the impact of ZIKV infection on RBCs over the course of infection. ZIKV-infected blood donors (n = 25) were identified through molecular and serologic methods, which included nucleic acid amplification testing and real-time polymerase chain reaction (PCR) for detection of ZIKV RNA and enzyme-linked immunosorbent assay (ELISA) for detection of flavivirus-specific IgM and IgG.
    RESULTS: In ZIKV RNA-positive donors, we observed lower glucose and lactate levels, and higher levels of ribose phosphate, suggestive of the activation of the pentose phosphate pathway. The top pathways altered in RBCs from ZIKV-IgM-positive donors include amino acid metabolism and biosynthesis, fatty acid metabolism and biosynthesis, linoleic acid and arachidonate metabolism and glutathione metabolism. RBCs from ZIKV-infected donors had increased levels of early glycolytic metabolites, and higher levels of metabolites of the pentose phosphate pathway. Alterations in acyl-carnitine and fatty acid metabolism are consistent with impaired membrane lipid homeostasis in RBCs from ZIKV IgM positive donors.
    CONCLUSION: RBC from healthy blood donors who had been infected by ZIKV are characterized by long-lasting metabolic alterations even months after infection has resolved.
    Keywords:  Zika virus; erythrocyte; lipidomics; metabolic reprogramming; metabolomics; viral infection
    DOI:  https://doi.org/10.1111/trf.16851
  14. Sci China Life Sci. 2022 Mar 10.
    A urinary proteomic landscape of COVID-19 progression identifies signaling pathways and therapeutic options.
    Yuntao Liu, Lan Song, Nairen Zheng, Jinwen Shi, Hongxing Wu, Xing Yang, Nianci Xue, Xing Chen, Yimin Li, Changqing Sun, Cha Chen, Lijuan Tang, Xiaotian Ni, Yi Wang, Yaling Shi, Jianwen Guo, Guangshun Wang, Zhongde Zhang, Jun Qin.
      Signaling pathway alterations in COVID-19 of living humans as well as therapeutic targets of the host proteins are not clear. We analyzed 317 urine proteomes, including 86 COVID-19, 55 pneumonia and 176 healthy controls, and identified specific RNA virus detector protein DDX58/RIG-I only in COVID-19 samples. Comparison of the COVID-19 urinary proteomes with controls revealed major pathway alterations in immunity, metabolism and protein localization. Biomarkers that may stratify severe symptoms from moderate ones suggested that macrophage induced inflammation and thrombolysis may play a critical role in worsening the disease. Hyper activation of the TCA cycle is evident and a macrophage enriched enzyme CLYBL is up regulated in COVID-19 patients. As CLYBL converts the immune modulatory TCA cycle metabolite itaconate through the citramalyl-CoA intermediate to acetyl-CoA, an increase in CLYBL may lead to the depletion of itaconate, limiting its anti-inflammatory function. These observations suggest that supplementation of itaconate and inhibition of CLYBL are possible therapeutic options for treating COVID-19, opening an avenue of modulating host defense as a means of combating SARS-CoV-2 viruses.
    Keywords:  CLYBL; COVID-19; itaconate; proteome; urine
    DOI:  https://doi.org/10.1007/s11427-021-2070-y
  15. Front Immunol. 2022 ;13 825171
    Amelioration of Endotoxemia by a Synthetic Analog of Omega-3 Epoxyeicosanoids.
    Akira Shikuma, Daisuke Kami, Ryotaro Maeda, Yosuke Suzuki, Arata Sano, Toshihiko Taya, Takehiro Ogata, Anne Konkel, Satoaki Matoba, Wolf-Hagen Schunck, Satoshi Gojo.
      Sepsis, a systemic inflammatory response to pathogenic factors, is a difficult to treat life-threatening condition associated with cytokine and eicosanoid storms and multi-organ damage. Omega-3 polyunsaturated fatty acids, such as eicosapentaenoic (EPA) and docosahexaenoic acid, are the precursors of potent anti-inflammatory lipid mediators, including 17,18-epoxyeicosatetraenoic acid (17,18-EEQ), the main metabolite of EPA generated by cytochrome P450 epoxygenases. Searching for novel therapeutic or preventative agents in sepsis, we tested a metabolically robust synthetic analog of 17,18-EEQ (EEQ-A) for its ability to reduce mortality, organ damage, and pro-inflammatory cytokine transcript level in a mouse model of lipopolysaccharide (LPS)-induced endotoxemia, which is closely related to sepsis. Overall survival significantly improved following preventative EEQ-A administration along with decreased transcript level of pro-inflammatory cytokines. On the other hand, the therapeutic protocol was effective in improving survival at 48 hours but insignificant at 72 hours. Histopathological analyses showed significant reductions in hemorrhagic and necrotic damage and infiltration in the liver. In vitro studies with THP-1 and U937 cells showed EEQ-A mediated repression of LPS-induced M1 polarization and enhancement of IL-4-induced M2 polarization of macrophages. Moreover, EEQ-A attenuated the LPS-induced decline of mitochondrial function in THP-1 cells, as indicated by increased basal respiration and ATP production as well as reduction of the metabolic shift to glycolysis. Taken together, these data demonstrate that EEQ-A has potent anti-inflammatory and immunomodulatory properties that may support therapeutic strategies for ameliorating the endotoxemia.
    Keywords:  Inflammation; Macrophage; Mitochondria; Omega-3; Unsaturated fatty acids
    DOI:  https://doi.org/10.3389/fimmu.2022.825171
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