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Daruich A, Picard E, Guégan J, Jaworski T, Parenti L, Delaunay K, Naud MC, Berdugo M, Boatright JH, Behar-Cohen F. Comparative Analysis of Urso- and Tauroursodeoxycholic Acid Neuroprotective Effects on Retinal Degeneration Models. Pharmaceuticals (Basel) 2022; 15:334. [PMID: 35337132 PMCID: PMC8955596 DOI: 10.3390/ph15030334] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/24/2022] [Accepted: 03/01/2022] [Indexed: 02/01/2023] Open
Abstract
Ursodeoxycholic (UDCA) and tauroursodeoxycholic (TUDCA) acids have shown neuroprotective properties in neurodegenerative diseases, but differential effects of the two bile acids have been poorly explored. The aim of this study was to evaluate the neuroprotective effects of UDCA versus TUDCA in a neuroretinal degeneration model and to compare transcriptionally regulated pathways. The WERI-Rb-1 human cone-like cell line and retinal explants were exposed to albumin and TUDCA or UDCA. Viability, cell death, and microglial activation were quantified. Transcriptionally regulated pathways were analyzed after RNA sequencing using the edgeR bioconductor package. Pre-treatment of cone-like cells with UDCA or TUDCA significantly protected cells from albumin toxicity. On retinal explants, either bile acid reduced apoptosis, necroptosis, and microglia activation at 6 h. TUDCA induced the regulation of 463 genes, whilst 31 genes were regulated by UDCA. Only nineteen common genes were regulated by both bile acids, mainly involved in iron control, cell death, oxidative stress, and cell metabolism. As compared to UDCA, TUDCA up-regulated genes involved in endoplasmic reticulum stress pathways and down-regulated genes involved in axonal and neuronal development. Either bile acid protected against albumin-induced cell loss. However, TUDCA regulated substantially more neuroprotective genes than UDCA.
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Affiliation(s)
- Alejandra Daruich
- From Physiopathology of Ocular Diseases to Clinical Development, Centre de Recherche des Cordeliers, Sorbonne University, Paris University, Inserm, F-75006 Paris, France; (E.P.); (T.J.); (L.P.); (K.D.); (M.-C.N.); (M.B.); (F.B.-C.)
- Ophthalmology Department, Necker-Enfants Malades University Hospital, Assistance Publique Hôpitaux de Paris, Paris University, F-75015 Paris, France
| | - Emilie Picard
- From Physiopathology of Ocular Diseases to Clinical Development, Centre de Recherche des Cordeliers, Sorbonne University, Paris University, Inserm, F-75006 Paris, France; (E.P.); (T.J.); (L.P.); (K.D.); (M.-C.N.); (M.B.); (F.B.-C.)
| | - Justine Guégan
- Institut du Cerveau (ICM), INSERM, CNRS, AP-HP, Sorbonne University, Pitié-Salpêtrière University Hospital, F-75013 Paris, France;
| | - Thara Jaworski
- From Physiopathology of Ocular Diseases to Clinical Development, Centre de Recherche des Cordeliers, Sorbonne University, Paris University, Inserm, F-75006 Paris, France; (E.P.); (T.J.); (L.P.); (K.D.); (M.-C.N.); (M.B.); (F.B.-C.)
| | - Léa Parenti
- From Physiopathology of Ocular Diseases to Clinical Development, Centre de Recherche des Cordeliers, Sorbonne University, Paris University, Inserm, F-75006 Paris, France; (E.P.); (T.J.); (L.P.); (K.D.); (M.-C.N.); (M.B.); (F.B.-C.)
| | - Kimberley Delaunay
- From Physiopathology of Ocular Diseases to Clinical Development, Centre de Recherche des Cordeliers, Sorbonne University, Paris University, Inserm, F-75006 Paris, France; (E.P.); (T.J.); (L.P.); (K.D.); (M.-C.N.); (M.B.); (F.B.-C.)
| | - Marie-Christine Naud
- From Physiopathology of Ocular Diseases to Clinical Development, Centre de Recherche des Cordeliers, Sorbonne University, Paris University, Inserm, F-75006 Paris, France; (E.P.); (T.J.); (L.P.); (K.D.); (M.-C.N.); (M.B.); (F.B.-C.)
| | - Marianne Berdugo
- From Physiopathology of Ocular Diseases to Clinical Development, Centre de Recherche des Cordeliers, Sorbonne University, Paris University, Inserm, F-75006 Paris, France; (E.P.); (T.J.); (L.P.); (K.D.); (M.-C.N.); (M.B.); (F.B.-C.)
| | - Jeffrey H. Boatright
- Department of Ophthalmology, Emory University School of Medicine, Atlanta, GA 30322, USA;
- Center of Excellence, Atlanta Veterans Administration Medical Center, Decatur, GA 30033, USA
| | - Francine Behar-Cohen
- From Physiopathology of Ocular Diseases to Clinical Development, Centre de Recherche des Cordeliers, Sorbonne University, Paris University, Inserm, F-75006 Paris, France; (E.P.); (T.J.); (L.P.); (K.D.); (M.-C.N.); (M.B.); (F.B.-C.)
- Ophtalmopole, Cochin Hospital, Assistance Publique Hôpitaux de Paris, Paris University, F-75015 Paris, France
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52
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Fiore A, Zeitler L, Russier M, Groß A, Hiller MK, Parker JL, Stier L, Köcher T, Newstead S, Murray PJ. Kynurenine importation by SLC7A11 propagates anti-ferroptotic signaling. Mol Cell 2022; 82:920-932.e7. [PMID: 35245456 DOI: 10.1016/j.molcel.2022.02.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 11/17/2021] [Accepted: 02/02/2022] [Indexed: 12/19/2022]
Abstract
IDO1 oxidizes tryptophan (TRP) to generate kynurenine (KYN), the substrate for 1-carbon and NAD metabolism, and is implicated in pro-cancer pathophysiology and infection biology. However, the mechanistic relationships between IDO1 in amino acid depletion versus product generation have remained a longstanding mystery. We found an unrecognized link between IDO1 and cell survival mediated by KYN that serves as the source for molecules that inhibit ferroptotic cell death. We show that this effect requires KYN export from IDO1-expressing cells, which is then available for non-IDO1-expressing cells via SLC7A11, the central transporter involved in ferroptosis suppression. Whether inside the "producer" IDO1+ cell or the "receiver" cell, KYN is converted into downstream metabolites, suppressing ferroptosis by ROS scavenging and activating an NRF2-dependent, AHR-independent cell-protective pathway, including SLC7A11, propagating anti-ferroptotic signaling. IDO1, therefore, controls a multi-pronged protection pathway from ferroptotic cell death, underscoring the need to re-evaluate the use of IDO1 inhibitors in cancer treatment.
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Affiliation(s)
- Alessandra Fiore
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Leonie Zeitler
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Marion Russier
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Annette Groß
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | | | - Joanne L Parker
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Luca Stier
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Thomas Köcher
- Vienna BioCenter Core Facilities GmbH, Vienna, Austria
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Peter J Murray
- Max Planck Institute of Biochemistry, 82152 Martinsried, Germany.
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53
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Maremonti F, Meyer C, Linkermann A. Mechanisms and Models of Kidney Tubular Necrosis and Nephron Loss. J Am Soc Nephrol 2022; 33:472-486. [PMID: 35022311 PMCID: PMC8975069 DOI: 10.1681/asn.2021101293] [Citation(s) in RCA: 69] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Understanding nephron loss is a primary strategy for preventing CKD progression. Death of renal tubular cells may occur by apoptosis during developmental and regenerative processes. However, during AKI, the transition of AKI to CKD, sepsis-associated AKI, and kidney transplantation ferroptosis and necroptosis, two pathways associated with the loss of plasma membrane integrity, kill renal cells. This necrotic type of cell death is associated with an inflammatory response, which is referred to as necroinflammation. Importantly, the necroinflammatory response to cells that die by necroptosis may be fundamentally different from the tissue response to ferroptosis. Although mechanisms of ferroptosis and necroptosis have recently been investigated in detail, the cell death propagation during tubular necrosis, although described morphologically, remains incompletely understood. Here, we argue that a molecular switch downstream of tubular necrosis determines nephron regeneration versus nephron loss. Unraveling the details of this "switch" must include the inflammatory response to tubular necrosis and regenerative signals potentially controlled by inflammatory cells, including the stimulation of myofibroblasts as the origin of fibrosis. Understanding in detail the molecular switch and the inflammatory responses to tubular necrosis can inform the discussion of therapeutic options.
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Affiliation(s)
- Francesca Maremonti
- Division of Nephrology, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany
| | - Claudia Meyer
- Division of Nephrology, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany
| | - Andreas Linkermann
- Division of Nephrology, University Hospital Carl Gustav Carus at the Technische Universität Dresden, Dresden, Germany .,Biotechnology Center, Technical University of Dresden, Dresden, Germany
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54
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Luo L, Wang H, Tian W, Zeng J, Huang Y, Luo H. Targeting ferroptosis for cancer therapy: iron metabolism and anticancer immunity. Am J Cancer Res 2021; 11:5508-5525. [PMID: 34873476 PMCID: PMC8640817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023] Open
Abstract
Ferroptosis is a new form of programmed cell death characterized by iron-dependent accumulation of lipid peroxidation, which plays an important role in cancer biology. Ferroptosis is involved in many biological processes, such as amino acid metabolism, glutathione metabolism, iron metabolism, and lipid metabolism. Iron is an essential trace element in a variety of normal cell processes, such as DNA synthesis and repair, cell respiration, metabolism and signal transduction, etc., and iron metabolism disorder has been considered as one of the metabolic markers of malignant cancer cells. In addition, iron is involved in the regulation of innate and adaptive immune responses, suggesting that targeted regulation of iron metabolism may contribute to anti-tumor immunity and cancer therapy. In this review, the regulatory mechanism of ferroptosis, the interaction between ferroptosis on tumor cell metabolism, and anti-tumor immunity were systematically reviewed. Immunotherapy combined with targeted regulation of iron and iron-dependent regulation of ferroptosis should be the focus of future ferroptosis research.
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Affiliation(s)
- Lianxiang Luo
- Southern Marine Science and Engineering Guangdong LaboratoryZhanjiang 524023, Guangdong, China
- The Marine Biomedical Research Institute, Guangdong Medical UniversityZhanjiang 524023, Guangdong, China
- The Marine Biomedical Research Institute of Guangdong ZhanjiangZhanjiang 524023, Guangdong, China
| | - Han Wang
- The First Clinical College, Guangdong Medical UniversityZhanjiang 524023, Guangdong, China
| | - Wen Tian
- The First Clinical College, Guangdong Medical UniversityZhanjiang 524023, Guangdong, China
| | - Jiayan Zeng
- The First Clinical College, Guangdong Medical UniversityZhanjiang 524023, Guangdong, China
| | - Yuru Huang
- The First Clinical College, Guangdong Medical UniversityZhanjiang 524023, Guangdong, China
| | - Hui Luo
- Southern Marine Science and Engineering Guangdong LaboratoryZhanjiang 524023, Guangdong, China
- The Marine Biomedical Research Institute, Guangdong Medical UniversityZhanjiang 524023, Guangdong, China
- The Marine Biomedical Research Institute of Guangdong ZhanjiangZhanjiang 524023, Guangdong, China
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55
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Xu Y, Zhang H, Sun Q, Geng R, Yuan F, Liu B, Chen Q. Immunomodulatory Effects of Tryptophan Metabolism in the Glioma Tumor Microenvironment. Front Immunol 2021; 12:730289. [PMID: 34659216 PMCID: PMC8517402 DOI: 10.3389/fimmu.2021.730289] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 09/20/2021] [Indexed: 12/12/2022] Open
Abstract
Gliomas are the most common primary malignant tumor in adults’ central nervous system. While current research on glioma treatment is advancing rapidly, there is still no breakthrough in long-term treatment. Abnormalities in the immune regulatory mechanism in the tumor microenvironment are essential to tumor cell survival. The alteration of amino acid metabolism is considered a sign of tumor cells, significantly impacting tumor cells and immune regulation mechanisms in the tumor microenvironment. Despite the fact that the metabolism of tryptophan in tumors is currently discussed in the literature, we herein focused on reviewing the immune regulation of tryptophan metabolism in the tumor microenvironment of gliomas and analyzed possible immune targets. The objective is to identify potential targets for the treatment of glioma and improve the efficiency of immunotherapy.
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Affiliation(s)
- Yang Xu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Huikai Zhang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qian Sun
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Rongxin Geng
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Fanen Yuan
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Baohui Liu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qianxue Chen
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
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56
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Cao W, Jin M, Yang K, Chen B, Xiong M, Li X, Cao G. Fenton/Fenton-like metal-based nanomaterials combine with oxidase for synergistic tumor therapy. J Nanobiotechnology 2021; 19:325. [PMID: 34656118 PMCID: PMC8520258 DOI: 10.1186/s12951-021-01074-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 10/04/2021] [Indexed: 02/07/2023] Open
Abstract
Chemodynamic therapy (CDT) catalyzed by transition metal and starvation therapy catalyzed by intracellular metabolite oxidases are both classic tumor treatments based on nanocatalysts. CDT monotherapy has limitations including low catalytic efficiency of metal ions and insufficient endogenous hydrogen peroxide (H2O2). Also, single starvation therapy shows limited ability on resisting tumors. The “metal-oxidase” cascade catalytic system is to introduce intracellular metabolite oxidases into the metal-based nanoplatform, which perfectly solves the shortcomings of the above-mentioned monotherapiesIn this system, oxidases can not only consume tumor nutrients to produce a “starvation effect”, but also provide CDT with sufficient H2O2 and a suitable acidic environment, which further promote synergy between CDT and starvation therapy, leading to enhanced antitumor effects. More importantly, the “metal-oxidase” system can be combined with other antitumor therapies (such as photothermal therapy, hypoxia-activated drug therapy, chemotherapy, and immunotherapy) to maximize their antitumor effects. In addition, both metal-based nanoparticles and oxidases can activate tumor immunity through multiple pathways, so the combination of the “metal-oxidase” system with immunotherapy has a powerful synergistic effect. This article firstly introduced the metals which induce CDT and the oxidases which induce starvation therapy and then described the “metal-oxidase” cascade catalytic system in detail. Moreover, we highlight the application of the “metal-oxidase” system in combination with numerous antitumor therapies, especially in combination with immunotherapy, expecting to provide new ideas for tumor treatment.
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Affiliation(s)
- Wei Cao
- Department of General Surgery, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, People's Republic of China
| | - Mengyao Jin
- Department of General Surgery, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, People's Republic of China
| | - Kang Yang
- Department of General Surgery, The Fourth Affiliated Hospital of Anhui Medical University, Hefei, 230022, People's Republic of China
| | - Bo Chen
- Department of General Surgery, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, People's Republic of China.
| | - Maoming Xiong
- Department of General Surgery, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, People's Republic of China.
| | - Xiang Li
- State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, People's Republic of China.
| | - Guodong Cao
- Department of General Surgery, First Affiliated Hospital of Anhui Medical University, Hefei, 230022, People's Republic of China.
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57
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Hofer F, Di Sario G, Musiu C, Sartoris S, De Sanctis F, Ugel S. A Complex Metabolic Network Confers Immunosuppressive Functions to Myeloid-Derived Suppressor Cells (MDSCs) within the Tumour Microenvironment. Cells 2021; 10:cells10102700. [PMID: 34685679 PMCID: PMC8534848 DOI: 10.3390/cells10102700] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 10/01/2021] [Accepted: 10/04/2021] [Indexed: 12/19/2022] Open
Abstract
Myeloid-derived suppressor cells (MDSCs) constitute a plastic and heterogeneous cell population among immune cells within the tumour microenvironment (TME) that support cancer progression and resistance to therapy. During tumour progression, cancer cells modify their metabolism to sustain an increased energy demand to cope with uncontrolled cell proliferation and differentiation. This metabolic reprogramming of cancer establishes competition for nutrients between tumour cells and leukocytes and most importantly, among tumour-infiltrating immune cells. Thus, MDSCs that have emerged as one of the most decisive immune regulators of TME exhibit an increase in glycolysis and fatty acid metabolism and also an upregulation of enzymes that catabolise essential metabolites. This complex metabolic network is not only crucial for MDSC survival and accumulation in the TME but also for enhancing immunosuppressive functions toward immune effectors. In this review, we discuss recent progress in the field of MDSC-associated metabolic pathways that could facilitate therapeutic targeting of these cells during cancer progression.
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Affiliation(s)
| | | | | | | | | | - Stefano Ugel
- Correspondence: ; Tel.: +39-045-8126451; Fax: +39-045-8126455
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58
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Inducible protein expression in piggyBac transposase mediated stable HEK293 cell pools. Methods Enzymol 2021; 660:321-339. [PMID: 34742396 DOI: 10.1016/bs.mie.2021.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Described here is the use of piggyBac transposase generated HEK293 stable cell pools for doxycycline-inducible protein production. The key benefits of the system are that low amounts of plasmid DNA are needed for transfection, high levels of protein expression can be achieved also for toxic proteins at robust scalability and reproducibility and the recombinant cell line can be stored as frozen cell bank. Transfection, selection, expression and purification of enhanced green fluorescence protein (eGFP) and SARS-CoV-2 Spike protein are described in this chapter.
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59
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Chen X, Kang R, Kroemer G, Tang D. Ferroptosis in infection, inflammation, and immunity. THE JOURNAL OF EXPERIMENTAL MEDICINE 2021; 218:212093. [PMID: 33978684 PMCID: PMC8126980 DOI: 10.1084/jem.20210518] [Citation(s) in RCA: 275] [Impact Index Per Article: 91.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/08/2021] [Accepted: 04/20/2021] [Indexed: 12/12/2022]
Abstract
Ferroptosis is a type of regulated necrosis that is triggered by a combination of iron toxicity, lipid peroxidation, and plasma membrane damage. The upstream inducers of ferroptosis can be divided into two categories (biological versus chemical) and activate two major pathways (the extrinsic/transporter versus the intrinsic/enzymatic pathways). Excessive or deficient ferroptotic cell death is implicated in a growing list of physiological and pathophysiological processes, coupled to a dysregulated immune response. This review focuses on new discoveries related to how ferroptotic cells and their spilled contents shape innate and adaptive immunity in health and disease. Understanding the immunological characteristics and activity of ferroptotic death not only illuminates an intersection between cell death and immunity but may also lead to the development of novel treatment approaches for immunopathological diseases.
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Affiliation(s)
- Xin Chen
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, The Third Affiliated Hospital, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China.,Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, China
| | - Rui Kang
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Guido Kroemer
- Centre de Recherche des Cordeliers, Equipe labellisée par la Ligue contre le cancer, Université de Paris, Sorbonne Université, Institut national de la santé et de la recherche médicale U1138, Institut Universitaire de France, Paris, France.,Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France.,Pôle de Biologie, Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, Paris, France.,Suzhou Institute for Systems Biology, Chinese Academy of Sciences, Suzhou, China.,Department of Women's and Children's Health, Karolinska University Hospital, Stockholm, Sweden
| | - Daolin Tang
- Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, The Third Affiliated Hospital, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, China.,Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX, USA
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60
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Castellano F, Prevost-Blondel A, Cohen JL, Molinier-Frenkel V. What role for AHR activation in IL4I1-mediated immunosuppression ? Oncoimmunology 2021; 10:1924500. [PMID: 34026337 PMCID: PMC8118450 DOI: 10.1080/2162402x.2021.1924500] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The amino-acid catabolizing enzyme Interleukin-4 induced gene 1 (IL4I1) remains poorly characterized despite it is emerging as a pertinent therapeutic target for cancer. IL4I1 is secreted in the synaptic cleft by antigen-presenting cells. It inhibits TCR signaling, modulates naïve T cell differentiation and limits effector T cell proliferation. IL4I1 expression in tumors shapes the tumor microenvironment and impairs the antitumor cytotoxic T cell response, thereby facilitating cancer immune escape. Several mechanisms participate in these effects. Recent data suggest a role of new IL4I1 metabolites in activation of the aryl-hydrocarbon receptor (AHR). Here, we observe that expression of IL4I1 is poorly correlated with that of validated targets of AHR in human cancers. Moreover, dendritic cells do not upregulate AHR target genes in relation with IL4I1 expression in vivo. Finally, IL4I1 activity toward tryptophan leading to production of AHR-activating products is very low, and should be negligible when tryptophan-degrading enzymes of higher affinity compete for the substrate. We recently showed that IL4I1 expression by dendritic cells directly regulates immune synapse formation and modulates the repertoire and memory differentiation of responding CD8 T cells after viral infection. Thus, IL4I1 may restrain tumor control through regulating the priming of tumor-specific CD8 T cells, independently of AHR activation.
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Affiliation(s)
- Flavia Castellano
- INSERM, IMRB, Univ Paris Est Creteil, Creteil, France.,Departement d'Hematologie-Immunologie, AP-HP, Hopital Henri Mondor, Créteil, France
| | | | - José L Cohen
- INSERM, IMRB, Univ Paris Est Creteil, Creteil, France.,Centre d'investigation Clinique en Biothérapie, AP-HP, Hopital Henri Mondor, Créteil, France
| | - Valérie Molinier-Frenkel
- INSERM, IMRB, Univ Paris Est Creteil, Creteil, France.,Departement d'Hematologie-Immunologie, AP-HP, Hopital Henri Mondor, Créteil, France
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