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Qi Y, Chen L, Ding S, Shen X, Wang Z, Qi H, Yang S. Neutrophil extracellular trap-induced ferroptosis promotes abdominal aortic aneurysm formation via SLC25A11-mediated depletion of mitochondrial glutathione. Free Radic Biol Med 2024; 221:215-224. [PMID: 38796028 DOI: 10.1016/j.freeradbiomed.2024.05.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2024] [Revised: 05/01/2024] [Accepted: 05/20/2024] [Indexed: 05/28/2024]
Abstract
BACKGROUND Neutrophil extracellular traps (NETs) induce oxidative stress, which may initiate ferroptosis, an iron-dependent programmed cell death, during abdominal aortic aneurysm (AAA) formation. Mitochondria regulate the progression of ferroptosis, which is characterized by the depletion of mitochondrial glutathione (mitoGSH) levels. However, the mechanisms are poorly understood. This study examined the role of mitoGSH in regulating NET-induced ferroptosis of smooth muscle cells (SMCs) during AAA formation. METHODS Concentrations of NET markers were tested in plasma samples. Western blotting and immunofluorescent staining were performed to detect the expression and localization of NET and ferroptosis markers in tissue samples. The role of NETs and SMC ferroptosis during AAA formation was investigated using peptidyl arginine deiminase 4 gene (Padi4) knockout or treatment with a PAD4 inhibitor, ferroptosis inhibitor or activator in an angiotensin II-induced AAA mouse model. The regulatory effect of SLC25A11, a mitochondrial glutathione transporter, on mitoGSH and NET-induced ferroptosis of SMCs was investigated using in vitro and in vivo experiments. Transmission electron microscopy was used to detect mitochondrial damage. Blue native polyacrylamide gel electrophoresis was used to analyze the dimeric and monomeric forms of the protein. RESULTS Significantly elevated levels of NETosis and ferroptosis markers in aortic tissue samples were observed during AAA formation. Specifically, NETs promoted AAA formation by inducing ferroptosis of SMCs. Subsequently, SLC25A11 was identified as a potential biomarker for evaluating the clinical prognosis of patients with AAA. Furthermore, NETs decreased the stability and dimerization of SLC25A11, leading to the depletion of mitoGSH. This depletion induced the ferroptosis of SMCs and promoted AAA formation. CONCLUSION During AAA formation, NETs regulate the stability of the mitochondrial carrier protein SLC25A11, leading to the depletion of mitoGSH and subsequent activation of NET-induced ferroptosis of SMCs. Preventing mitoGSH depletion and ferroptosis in SMCs is a potential strategy for treating AAA.
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Affiliation(s)
- Yanqing Qi
- Cardiovascular Surgery Department, The First Affiliated Hospital of Ningbo University, No.59 Liuting Street, Haishu District, Ningbo City, Zhejiang Province, 315000, China
| | - Liang Chen
- Institute of Vascular Surgery, Department of Vascular Surgery, Zhongshan Hospital, Fudan University, Shanghai, China; National Clinical Research Center for Interventional Medicine, Shanghai, 200032, China
| | - Shanshan Ding
- Cardiovascular Surgery Department, The First Affiliated Hospital of Ningbo University, No.59 Liuting Street, Haishu District, Ningbo City, Zhejiang Province, 315000, China
| | - Xiaowei Shen
- Cardiovascular Surgery Department, The First Affiliated Hospital of Ningbo University, No.59 Liuting Street, Haishu District, Ningbo City, Zhejiang Province, 315000, China
| | - Zhifang Wang
- Cardiovascular Surgery Department, The First Affiliated Hospital of Ningbo University, No.59 Liuting Street, Haishu District, Ningbo City, Zhejiang Province, 315000, China
| | - Haozhe Qi
- Department of Vascular Surgery, Ren Ji Hospital, Shanghai Jiao Tong University, School of Medicine, Pujian Road 160, Shanghai, 200127, China
| | - Shuofei Yang
- Department of Vascular Surgery, Ren Ji Hospital, Shanghai Jiao Tong University, School of Medicine, Pujian Road 160, Shanghai, 200127, China.
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Kaye SD, Goyani S, Tomar D. MICU1's calcium sensing beyond mitochondrial calcium uptake. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119714. [PMID: 38555977 PMCID: PMC11194792 DOI: 10.1016/j.bbamcr.2024.119714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/19/2024] [Accepted: 03/21/2024] [Indexed: 04/02/2024]
Abstract
The discovery of MICU1 as gatekeeper of mitochondrial calcium (mCa2+) entry has transformed our understanding of mCa2+ flux. Recent studies revealed an additional role of MICU1 as a Ca2+ sensor at MICOS (mitochondrial contact site and cristae organizing system). MICU1's presence at MICOS suggests its involvement in coordinating Ca2+ signaling and mitochondrial ultrastructure. Besides its role in Ca2+ regulation, MICU1 influences cellular signaling pathways including transcription, epigenetic regulation, metabolism, and cell death, thereby affecting human health. Here, we summarize recent findings on MICU1's canonical and noncanonical functions, and its relevance to human health and diseases.
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Affiliation(s)
- Sarah D Kaye
- Department of Internal Medicine, Section of Gerontology and Geriatric Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Shanikumar Goyani
- Department of Internal Medicine, Section of Cardiovascular Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | - Dhanendra Tomar
- Department of Internal Medicine, Section of Cardiovascular Medicine, Section of Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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Naveh CA, Roberts K, Zakrzewski P, Rice CM, Ponce-Garcia FM, Fleming K, Thompson M, Panyapiean N, Jiang H, Diezmann S, Moura PL, Toye AM, Amulic B. Neutrophils cultured ex vivo from CD34 + stem cells are immature and genetically tractable. J Transl Med 2024; 22:526. [PMID: 38822352 PMCID: PMC11143668 DOI: 10.1186/s12967-024-05337-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 05/22/2024] [Indexed: 06/02/2024] Open
Abstract
BACKGROUND Neutrophils are granulocytes with essential antimicrobial effector functions and short lifespans. During infection or sterile inflammation, emergency granulopoiesis leads to release of immature neutrophils from the bone marrow, serving to boost circulating neutrophil counts. Steady state and emergency granulopoiesis are incompletely understood, partly due to a lack of genetically amenable models of neutrophil development. METHODS We optimised a method for ex vivo production of human neutrophils from CD34+ haematopoietic progenitors. Using flow cytometry, we phenotypically compared cultured neutrophils with native neutrophils from donors experiencing emergency granulopoiesis, and steady state neutrophils from non-challenged donors. We carry out functional and proteomic characterisation of cultured neutrophils and establish genome editing of progenitors. RESULTS We obtain high yields of ex vivo cultured neutrophils, which phenotypically resemble immature neutrophils released into the circulation during emergency granulopoiesis. Cultured neutrophils have similar rates of ROS production and bacterial killing but altered degranulation, cytokine release and antifungal activity compared to mature neutrophils isolated from peripheral blood. These differences are likely due to incomplete synthesis of granule proteins, as demonstrated by proteomic analysis. CONCLUSION Ex vivo cultured neutrophils are genetically tractable via genome editing of precursors and provide a powerful model system for investigating the properties and behaviour of immature neutrophils.
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Affiliation(s)
- Claire A Naveh
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Kiran Roberts
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Przemysław Zakrzewski
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Christopher M Rice
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Fernando M Ponce-Garcia
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Kathryn Fleming
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Megan Thompson
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Nawamin Panyapiean
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Huan Jiang
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Stephanie Diezmann
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK
| | - Pedro L Moura
- Center for Hematology and Regenerative Medicine, Department of Medicine Huddinge (MedH), Karolinska Institutet, Huddinge, Sweden
| | - Ashley M Toye
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
| | - Borko Amulic
- School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, BS8 1TD, UK.
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Marques E, Kramer R, Ryan DG. Multifaceted mitochondria in innate immunity. NPJ METABOLIC HEALTH AND DISEASE 2024; 2:6. [PMID: 38812744 PMCID: PMC11129950 DOI: 10.1038/s44324-024-00008-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/14/2024] [Indexed: 05/31/2024]
Abstract
The ability of mitochondria to transform the energy we obtain from food into cell phosphorylation potential has long been appreciated. However, recent decades have seen an evolution in our understanding of mitochondria, highlighting their significance as key signal-transducing organelles with essential roles in immunity that extend beyond their bioenergetic function. Importantly, mitochondria retain bacterial motifs as a remnant of their endosymbiotic origin that are recognised by innate immune cells to trigger inflammation and participate in anti-microbial defence. This review aims to explore how mitochondrial physiology, spanning from oxidative phosphorylation (OxPhos) to signalling of mitochondrial nucleic acids, metabolites, and lipids, influences the effector functions of phagocytes. These myriad effector functions include macrophage polarisation, efferocytosis, anti-bactericidal activity, antigen presentation, immune signalling, and cytokine regulation. Strict regulation of these processes is critical for organismal homeostasis that when disrupted may cause injury or contribute to disease. Thus, the expanding body of literature, which continues to highlight the central role of mitochondria in the innate immune system, may provide insights for the development of the next generation of therapies for inflammatory diseases.
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Affiliation(s)
- Eloïse Marques
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Robbin Kramer
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Dylan G. Ryan
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
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Galy B, Conrad M, Muckenthaler M. Mechanisms controlling cellular and systemic iron homeostasis. Nat Rev Mol Cell Biol 2024; 25:133-155. [PMID: 37783783 DOI: 10.1038/s41580-023-00648-1] [Citation(s) in RCA: 110] [Impact Index Per Article: 110.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2023] [Indexed: 10/04/2023]
Abstract
In mammals, hundreds of proteins use iron in a multitude of cellular functions, including vital processes such as mitochondrial respiration, gene regulation and DNA synthesis or repair. Highly orchestrated regulatory systems control cellular and systemic iron fluxes ensuring sufficient iron delivery to target proteins is maintained, while limiting its potentially deleterious effects in iron-mediated oxidative cell damage and ferroptosis. In this Review, we discuss how cells acquire, traffick and export iron and how stored iron is mobilized for iron-sulfur cluster and haem biogenesis. Furthermore, we describe how these cellular processes are fine-tuned by the combination of various sensory and regulatory systems, such as the iron-regulatory protein (IRP)-iron-responsive element (IRE) network, the nuclear receptor co-activator 4 (NCOA4)-mediated ferritinophagy pathway, the prolyl hydroxylase domain (PHD)-hypoxia-inducible factor (HIF) axis or the nuclear factor erythroid 2-related factor 2 (NRF2) regulatory hub. We further describe how these pathways interact with systemic iron homeostasis control through the hepcidin-ferroportin axis to ensure appropriate iron fluxes. This knowledge is key for the identification of novel therapeutic opportunities to prevent diseases of cellular and/or systemic iron mismanagement.
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Affiliation(s)
- Bruno Galy
- German Cancer Research Center (DKFZ), Division of Virus-associated Carcinogenesis (F170), Heidelberg, Germany
| | - Marcus Conrad
- Helmholtz Zentrum München, Institute of Metabolism and Cell Death, Neuherberg, Germany
| | - Martina Muckenthaler
- Department of Paediatric Hematology, Oncology and Immunology, University of Heidelberg, Heidelberg, Germany.
- Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany.
- German Centre for Cardiovascular Research (DZHK), Partner site Heidelberg/Mannheim, Heidelberg, Germany.
- Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany.
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Pulikkot S, Zhao M, Fan Z. Real-Time Measurement of the Mitochondrial Bioenergetic Profile of Neutrophils. J Vis Exp 2023:10.3791/64971. [PMID: 37335127 PMCID: PMC11145524 DOI: 10.3791/64971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023] Open
Abstract
Neutrophils are the first line of defense and the most abundant leukocytes in humans. These effector cells perform functions such as phagocytosis and oxidative burst, and create neutrophil extracellular traps (NETs) for microbial clearance. New insights into the metabolic activities of neutrophils challenge the early concept that they primarily rely on glycolysis. Precise measurement of metabolic activities can unfold different metabolic requirements of neutrophils, including the tricarboxylic acid (TCA) cycle (also known as the Krebs cycle), oxidative phosphorylation (OXPHOS), pentose phosphate pathway (PPP), and fatty acid oxidation (FAO) under physiological conditions and in disease states. This paper describes a step-by-step protocol and prerequirements to measure oxygen consumption rate (OCR) as an indicator of mitochondrial respiration on mouse bone marrow-derived neutrophils, human blood-derived neutrophils, and the neutrophil-like HL60 cell line, using metabolic flux analysis on a metabolic extracellular flux analyzer. This method can be used for quantifying the mitochondrial functions of neutrophils under normal and disease conditions.
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Affiliation(s)
| | - Meng Zhao
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation; Department of Microbiology and Immunology, University of Oklahoma Health Science Center
| | - Zhichao Fan
- Department of Immunology, School of Medicine, UConn Health;
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Fefelova N, Wongjaikam S, Pamarthi SH, Siri-Angkul N, Comollo T, Kumari A, Garg V, Ivessa A, Chattipakorn SC, Chattipakorn N, Gwathmey JK, Xie LH. Deficiency of mitochondrial calcium uniporter abrogates iron overload-induced cardiac dysfunction by reducing ferroptosis. Basic Res Cardiol 2023; 118:21. [PMID: 37227592 PMCID: PMC10589903 DOI: 10.1007/s00395-023-00990-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/11/2023] [Accepted: 05/02/2023] [Indexed: 05/26/2023]
Abstract
Iron overload associated cardiac dysfunction remains a significant clinical challenge whose underlying mechanism(s) have yet to be defined. We aim to evaluate the involvement of the mitochondrial Ca2+ uniporter (MCU) in cardiac dysfunction and determine its role in the occurrence of ferroptosis. Iron overload was established in control (MCUfl/fl) and conditional MCU knockout (MCUfl/fl-MCM) mice. LV function was reduced by chronic iron loading in MCUfl/fl mice, but not in MCUfl/fl-MCM mice. The level of mitochondrial iron and reactive oxygen species were increased and mitochondrial membrane potential and spare respiratory capacity (SRC) were reduced in MCUfl/fl cardiomyocytes, but not in MCUfl/fl-MCM cardiomyocytes. After iron loading, lipid oxidation levels were increased in MCUfl/fl, but not in MCUfl/fl-MCM hearts. Ferrostatin-1, a selective ferroptosis inhibitor, reduced lipid peroxidation and maintained LV function in vivo after chronic iron treatment in MCUfl/fl hearts. Isolated cardiomyocytes from MCUfl/fl mice demonstrated ferroptosis after acute iron treatment. Moreover, Ca2+ transient amplitude and cell contractility were both significantly reduced in isolated cardiomyocytes from chronically Fe treated MCUfl/fl hearts. However, ferroptosis was not induced in cardiomyocytes from MCUfl/fl-MCM hearts nor was there a reduction in Ca2+ transient amplitude or cardiomyocyte contractility. We conclude that mitochondrial iron uptake is dependent on MCU, which plays an essential role in causing mitochondrial dysfunction and ferroptosis under iron overload conditions in the heart. Cardiac-specific deficiency of MCU prevents the development of ferroptosis and iron overload-induced cardiac dysfunction.
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Affiliation(s)
- Nadezhda Fefelova
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Suwakon Wongjaikam
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ, 07103, USA
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Sri Harika Pamarthi
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Natthaphat Siri-Angkul
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ, 07103, USA
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Thomas Comollo
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Anshu Kumari
- Department of Physiology, University of Maryland, Baltimore, MD, USA
| | - Vivek Garg
- Department of Physiology, University of Maryland, Baltimore, MD, USA
| | - Andreas Ivessa
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Siriporn C Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Nipon Chattipakorn
- Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
- Cardiac Electrophysiology Unit, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand
| | - Judith K Gwathmey
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, Rutgers University-New Jersey Medical School, Newark, NJ, 07103, USA.
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Cao Z, Zhao M, Sun H, Hu L, Chen Y, Fan Z. Roles of mitochondria in neutrophils. Front Immunol 2022; 13:934444. [PMID: 36081497 PMCID: PMC9447286 DOI: 10.3389/fimmu.2022.934444] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/19/2022] [Indexed: 01/25/2023] Open
Abstract
Neutrophils are the most abundant leukocyte in human blood. They are critical for fighting infections and are involved in inflammatory diseases. Mitochondria are indispensable for eukaryotic cells, as they control the biochemical processes of respiration and energy production. Mitochondria in neutrophils have been underestimated since glycolysis is a major metabolic pathway for fuel production in neutrophils. However, several studies have shown that mitochondria are greatly involved in multiple neutrophil functions as well as neutrophil-related diseases. In this review, we focus on how mitochondrial components, metabolism, and related genes regulate neutrophil functions and relevant diseases.
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Affiliation(s)
- Ziming Cao
- Department of Immunology, School of Medicine, UConn Health, Farmington, CT, United States
| | - Meng Zhao
- Arthritis and Clinical Immunology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States,Department of Microbiology and Immunology, University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Hao Sun
- Department of Medicine, University of California San Diego, La Jolla, CA, United States
| | - Liang Hu
- Academy of Integrative Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yunfeng Chen
- Department of Biochemistry and Molecular Biology and Department of Pathology, University of Texas Medical Branch, Galveston, TX, United States
| | - Zhichao Fan
- Department of Immunology, School of Medicine, UConn Health, Farmington, CT, United States,*Correspondence: Zhichao Fan,
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Monteith AJ, Miller JM, Beavers WN, Juttukonda LJ, Skaar EP. Increased Dietary Manganese Impairs Neutrophil Extracellular Trap Formation Rendering Neutrophils Ineffective at Combating Staphylococcus aureus. Infect Immun 2022; 90:e0068521. [PMID: 35191757 PMCID: PMC8929375 DOI: 10.1128/iai.00685-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 01/06/2022] [Indexed: 11/20/2022] Open
Abstract
Dietary metals can modify the risk to infection. Previously, we demonstrated that heightened dietary manganese (Mn) during systemic Staphylococcus aureus infection increases S. aureus virulence. However, immune cells also operate in these same environments and the effect of dietary Mn on neutrophil function in vivo has not been assessed. This study reveals that increased concentrations of Mn impairs mitochondrial respiration and superoxide production in neutrophils responding to S. aureus. As a result, high Mn accelerates primary degranulation, while impairing suicidal neutrophil extracellular trap (NET) formation, which decreases bactericidal activity. In vivo, elevated dietary Mn accumulated extracellularly in the heart, indicating that excess Mn may be more bioavailable in the heart. Coinciding with this phenotype, neutrophil function in the heart was most impacted by a high Mn diet, as neutrophils produced lower levels of mitochondrial superoxide and underwent less suicidal NET formation. Consistent with an ineffective neutrophil response when mice are on a high Mn diet, S. aureus burdens were increased in the heart and mice were more susceptible to systemic infection. Therefore, elevated dietary Mn not only affects S. aureus but also renders neutrophils less capable of restricting staphylococcal infection.
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Affiliation(s)
- Andrew J. Monteith
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jeanette M. Miller
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - William N. Beavers
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pathobiological Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, Louisiana, USA
| | - Lillian J. Juttukonda
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Eric P. Skaar
- Department of Pathology, Microbiology, & Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection, Immunology, & Inflammation, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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von Köckritz-Blickwede M, Winstel V. Molecular Prerequisites for Neutrophil Extracellular Trap Formation and Evasion Mechanisms of Staphylococcus aureus. Front Immunol 2022; 13:836278. [PMID: 35237275 PMCID: PMC8884242 DOI: 10.3389/fimmu.2022.836278] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 01/19/2022] [Indexed: 12/15/2022] Open
Abstract
NETosis is a multi-facetted cellular process that promotes the formation of neutrophil extracellular traps (NETs). NETs as web-like structures consist of DNA fibers armed with granular proteins, histones, and microbicidal peptides, thereby exhibiting pathogen-immobilizing and antimicrobial attributes that maximize innate immune defenses against invading microbes. However, clinically relevant pathogens often tolerate entrapment and even take advantage of the remnants of NETs to cause persistent infections in mammalian hosts. Here, we briefly summarize how Staphylococcus aureus, a high-priority pathogen and causative agent of fatal diseases in humans as well as animals, catalyzes and concurrently exploits NETs during pathogenesis and recurrent infections. Specifically, we focus on toxigenic and immunomodulatory effector molecules produced by staphylococci that prime NET formation, and further highlight the molecular and underlying principles of suicidal NETosis compared to vital NET-formation by viable neutrophils in response to these stimuli. We also discuss the inflammatory potential of NET-controlled microenvironments, as excessive expulsion of NETs from activated neutrophils provokes local tissue injury and may therefore amplify staphylococcal disease severity in hospitalized or chronically ill patients. Combined with an overview of adaptation and counteracting strategies evolved by S. aureus to impede NET-mediated killing, these insights may stimulate biomedical research activities to uncover novel aspects of NET biology at the host-microbe interface.
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Affiliation(s)
- Maren von Köckritz-Blickwede
- Department of Biochemistry, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses (RIZ), University of Veterinary Medicine Hannover, Hannover, Germany
| | - Volker Winstel
- Research Group Pathogenesis of Bacterial Infections, TWINCORE, Centre for Experimental and Clinical Infection Research, a joint venture between the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany
- Institute of Medical Microbiology and Hospital Epidemiology, Hannover Medical School, Hannover, Germany
- *Correspondence: Volker Winstel,
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