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Kyung Kim J, Jo EK. Host and microbial regulation of mitochondrial reactive oxygen species during mycobacterial infections. Mitochondrion 2024; 75:101852. [PMID: 38360196 DOI: 10.1016/j.mito.2024.101852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/15/2024] [Accepted: 02/12/2024] [Indexed: 02/17/2024]
Abstract
Mycobacteria, including Mycobacterium tuberculosis (Mtb) and non-tuberculous mycobacteria (NTM), pose challenges in treatment due to their increased resistance to antibiotics. Following infection, mycobacteria and their components trigger robust innate and inflammatory immune responses intricately associated with the modulation of mitochondrial functions, including oxidative phosphorylation (OXPHOS) and metabolism. Certainly, mitochondrial reactive oxygen species (mtROS) are an inevitable by-product of OXPHOS and function as a bactericidal weapon; however, an excessive accumulation of mtROS are linked to pathological inflammation and necroptotic cell death during mycobacterial infection. Despite previous studies outlining various host pathways involved in regulating mtROS levels during antimicrobial responses in mycobacterial infection, our understanding of the precise mechanisms orchestrating the fine regulation of this response remains limited. Emerging evidence suggests that mycobacterial proteins play a role in targeting the mitochondria of the host, indicating the potential influence of microbial factors on mitochondrial functions within host cells. In this review, we provide an overview of how both host and Mtb factors influence mtROS generation during infection. A comprehensive study of host and microbial factors that target mtROS will shed light on innovative approaches for effectively managing drug-resistant mycobacterial infections.
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Affiliation(s)
- Jin Kyung Kim
- Department of Microbiology, Keimyung University School of Medicine, Daegu, Republic of Korea
| | - Eun-Kyeong Jo
- Infection Control Convergence Research Center, Chungnam National University School of Medicine, Daejeon, Republic of Korea; Department of Medical Science, Chungnam National University School of Medicine, Daejeon, Republic of Korea; Department of Microbiology, Chungnam National University School of Medicine, Daejeon, Republic of Korea.
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2
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Lee J, Lee SA, Son SH, Choi JA, Nguyen TD, Kim J, Son D, Song CH. Impaired mitophagy induces antimicrobial responses in macrophages infected with Mycobacterium tuberculosis. Cell Biosci 2023; 13:158. [PMID: 37649112 PMCID: PMC10470153 DOI: 10.1186/s13578-023-01107-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 08/18/2023] [Indexed: 09/01/2023] Open
Abstract
BACKGROUND Mitophagy, mitochondrial selective autophagy, plays a pivotal role in the maintenance of cellular homeostasis in response to cellular stress. However, the role of mitophagy in macrophages during infection has not been elucidated. To determine whether mitophagy regulates intracellular pathogen survival, macrophages were infected with Mycobacterium tuberculosis (Mtb), an intracellular bacterium. RESULTS We showed that Mtb-infected macrophages induced mitophagy through BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3) activation. In contrast, BNIP3-deficient macrophages failed to induce mitophagy, resulting in reduced mitochondrial membrane potential in response to Mtb infection. Moreover, the accumulation of damaged mitochondria due to BNIP3 deficiency generated higher levels of mitochondrial reactive oxygen species (mROS) compared to the control, suppressing the intracellular survival of Mtb. We observed that siBNIP3 suppressed intracellular Mtb in mice lungs. CONCLUSION We found that BNIP3 plays a critical role in the regulation of mitophagy during Mtb infection. The inhibition of mitophagy suppresses Mtb growth in macrophages through increased mROS production. Therefore, BNIP3 might be a novel therapeutic target for tuberculosis treatment.
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Affiliation(s)
- Junghwan Lee
- Department of Microbiology, Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa‑ro, Jung‑gu, Daejeon, 35015, South Korea
- Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa-ro, Jung-gu, Daejeon, 35015, South Korea
- Translational Immunology Institute, Chungnam National University, Daejeon, 34134, South Korea
| | - Seong-Ahn Lee
- Department of Microbiology, Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa‑ro, Jung‑gu, Daejeon, 35015, South Korea
- Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa-ro, Jung-gu, Daejeon, 35015, South Korea
| | - Sang-Hun Son
- Department of Microbiology, Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa‑ro, Jung‑gu, Daejeon, 35015, South Korea
- Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa-ro, Jung-gu, Daejeon, 35015, South Korea
| | - Ji-Ae Choi
- Department of Microbiology, Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa‑ro, Jung‑gu, Daejeon, 35015, South Korea
- Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa-ro, Jung-gu, Daejeon, 35015, South Korea
- Translational Immunology Institute, Chungnam National University, Daejeon, 34134, South Korea
| | - Tam Doan Nguyen
- Department of Microbiology, Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa‑ro, Jung‑gu, Daejeon, 35015, South Korea
- Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa-ro, Jung-gu, Daejeon, 35015, South Korea
| | - Jaewhan Kim
- Department of Microbiology, Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa‑ro, Jung‑gu, Daejeon, 35015, South Korea
- Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa-ro, Jung-gu, Daejeon, 35015, South Korea
| | - Doyi Son
- Department of Microbiology, Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa‑ro, Jung‑gu, Daejeon, 35015, South Korea
- Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa-ro, Jung-gu, Daejeon, 35015, South Korea
| | - Chang-Hwa Song
- Department of Microbiology, Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa‑ro, Jung‑gu, Daejeon, 35015, South Korea.
- Department of Medical Science, College of Medicine, Chungnam National University, 266 Munhwa-ro, Jung-gu, Daejeon, 35015, South Korea.
- Translational Immunology Institute, Chungnam National University, Daejeon, 34134, South Korea.
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3
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Maurice NM, Sadikot RT. Mitochondrial Dysfunction in Bacterial Infections. Pathogens 2023; 12:1005. [PMID: 37623965 PMCID: PMC10458073 DOI: 10.3390/pathogens12081005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/23/2023] [Accepted: 07/26/2023] [Indexed: 08/26/2023] Open
Abstract
Mitochondria are critical in numerous cellular processes, including energy generation. Bacterial pathogens target host cell mitochondria through various mechanisms to disturb the host response and improve bacterial survival. We review recent advances in the understanding of how bacteria cause mitochondrial dysfunction through perturbations in mitochondrial cell-death pathways, energy production, mitochondrial dynamics, mitochondrial quality control, DNA repair, and the mitochondrial unfolded protein response. We also briefly highlight possible therapeutic approaches aimed at restoring the host mitochondrial function as a novel strategy to enhance the host response to bacterial infection.
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Affiliation(s)
- Nicholas M. Maurice
- Department of Medicine, Division of Pulmonary, Allergy, Critical Care, and Sleep Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
- Atlanta Veterans Affairs Health Care System, Decatur, GA 30033, USA
| | - Ruxana T. Sadikot
- VA Nebraska Western Iowa Health Care System, Omaha, NE 68105, USA
- Division of Pulmonary, Critical Care & Sleep, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Mohareer K, Banerjee S. Mycobacterial infection alters host mitochondrial activity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2023. [DOI: 10.1016/bs.ircmb.2023.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
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5
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马 沁, 刘 莉, 于 嘉, 宫 照, 王 晓, 吴 晓, 邓 光. [TRAF6 promotes Bacillus Calmette- Guérin-induced macrophage apoptosis through the intrinsic apoptosis pathway]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2022; 42:1279-1287. [PMID: 36210699 PMCID: PMC9550557 DOI: 10.12122/j.issn.1673-4254.2022.09.02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Indexed: 06/16/2023]
Abstract
OBJECTIVE To investigate the role of tumor necrosis factor receptor-associated factor 6 (TRAF6) in regulating Bacillus Calmette-Guérin (BCG)-induced macrophage apoptosis. METHODS The expression of TRAF6 in peripheral blood samples of 50 patients with active tuberculosis (TB) and 50 healthy individuals were detected using quantitative real-time PCR (qPCR). RAW264.7 macrophages were infected with BCG at different MOI and for different lengths of time, and the changes in expressions of Caspase 3 and TRAF6 were detected with Western blotting and qPCR. In a RAW264.7 cell model of BCG infection with TRAF6 knockdown established using RNA interference technique, the bacterial load was measured and cell apoptotic rate and mitochondrial membrane potential (MMP) were determined with flow cytometry. The expression levels of TRAF6, Caspase 3, PARP, BAX and Bcl-2 in the cells were detected using Western blotting, and the expressions of TRAF6 and Caspase 3 were also examined with immunofluorescence assay. RESULTS The expression of TRAF6 was significantly upregulated in the peripheral blood of patients with active TB as compared with healthy subjects (P < 0.001). In RAW264.7 cells, BCG infection significantly increased the expressions of Caspase 3 and TRAF6, which were the highest in cells infected for 18 h and at the MOI of 15. TRAF6 knockdown caused a significant increase of bacterial load in BCG-infected macrophages (P=0.05), lowered the cell apoptotic rate (P < 0.001) and reduced the expressions of Caspase 3 (P=0.002) and PARP (P < 0.001). BCG-infected RAW264.7 cells showed a significantly increased MMP (P < 0.001), which was lowered by TRAF6 knockdown (P < 0.001); the cells with both TRAF6 knockdown and BCG infection showed a lowered BAX expression (P=0.005) and an increased expression of Bcl-2 (P=0.04). CONCLUSION TRAF6 promotes BCG-induced macrophage apoptosis by regulating the intrinsic apoptosis pathway.
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Affiliation(s)
- 沁梅 马
- 西部特色生物资源保护与利用教育部重点实验室,宁夏 银川 750021Key Lab of Ministry of Education for Protection and Utilization of Special Biological Resources in Western China
- 宁夏大学生命科学学院,宁夏 银川 750021College of Life Science, NingXia University, Yinchuan 750021, China
| | - 莉 刘
- 西部特色生物资源保护与利用教育部重点实验室,宁夏 银川 750021Key Lab of Ministry of Education for Protection and Utilization of Special Biological Resources in Western China
- 宁夏大学生命科学学院,宁夏 银川 750021College of Life Science, NingXia University, Yinchuan 750021, China
| | - 嘉霖 于
- 西部特色生物资源保护与利用教育部重点实验室,宁夏 银川 750021Key Lab of Ministry of Education for Protection and Utilization of Special Biological Resources in Western China
- 宁夏大学生命科学学院,宁夏 银川 750021College of Life Science, NingXia University, Yinchuan 750021, China
| | - 照乾 宫
- 西部特色生物资源保护与利用教育部重点实验室,宁夏 银川 750021Key Lab of Ministry of Education for Protection and Utilization of Special Biological Resources in Western China
- 宁夏大学生命科学学院,宁夏 银川 750021College of Life Science, NingXia University, Yinchuan 750021, China
| | - 晓平 王
- 宁夏回族自治区第四人民医院,宁夏 银川 750021Fourth People's Hospital of Ningxia Hui Autonomous Region, Yinchuan 750021, China
| | - 晓玲 吴
- 西部特色生物资源保护与利用教育部重点实验室,宁夏 银川 750021Key Lab of Ministry of Education for Protection and Utilization of Special Biological Resources in Western China
- 宁夏大学生命科学学院,宁夏 银川 750021College of Life Science, NingXia University, Yinchuan 750021, China
| | - 光存 邓
- 西部特色生物资源保护与利用教育部重点实验室,宁夏 银川 750021Key Lab of Ministry of Education for Protection and Utilization of Special Biological Resources in Western China
- 宁夏大学生命科学学院,宁夏 银川 750021College of Life Science, NingXia University, Yinchuan 750021, China
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Kim IS, Silwal P, Jo EK. Mitofusin 2, a key coordinator between mitochondrial dynamics and innate immunity. Virulence 2021; 12:2273-2284. [PMID: 34482801 PMCID: PMC8425681 DOI: 10.1080/21505594.2021.1965829] [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] [Indexed: 12/11/2022] Open
Abstract
Remodeling of mitochondrial dynamics and mitochondrial morphology plays a pivotal role in the maintenance of mitochondrial homeostasis in response to pathogenic attacks or stress stimuli. In addition to their role in metabolism and energy production, mitochondria participate in diverse biological functions, including innate immune responses driven by macrophages in response to infections or inflammatory stimuli. Mitofusin-2 (MFN2), a mitochondria-shaping protein regulating mitochondrial fusion and fission, plays a crucial role in linking mitochondrial function and innate immune responses. In this article, we review the role of MFN2 in the regulation of innate immune responses during viral and bacterial infections. We also summarize the current knowledge on the role of MFN2 in coordinating inflammatory, atherogenic, and fibrotic responses. MFN2-mediated crosstalk between mitochondrial dynamics and innate immune responses may determine the outcomes of pathogenic infections.
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Affiliation(s)
- In Soo Kim
- Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea.,Infection Control Convergence Research Center, Chungnam National University College of Medicine, Daejeon, Korea
| | - Prashanta Silwal
- Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea.,Infection Control Convergence Research Center, Chungnam National University College of Medicine, Daejeon, Korea
| | - Eun-Kyeong Jo
- Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Korea.,Infection Control Convergence Research Center, Chungnam National University College of Medicine, Daejeon, Korea
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7
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Mitochondrial fusion mediated by mitofusin 1 regulates macrophage mycobactericidal activity by enhancing autophagy. Infect Immun 2021; 89:e0030621. [PMID: 34370506 DOI: 10.1128/iai.00306-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mitochondria as a highly dynamic organelle continuously changes morphology and position during its life cycle. Mitochondrial dynamics including fission and fusion play a critical role in maintaining functional mitochondria for ATP production, which is directly linked to host defense against Mtb infection. However, how macrophages regulate mitochondrial dynamics during Mycobacterium tuberculosis (Mtb) infection remains elusive. In this study, we found that Mtb infection induced mitochondrial fusion through enhancing the expression of mitofusin 1 (MFN1), which resulted in increased ATP production. Silencing MFN1 inhibited mitochondrial fusion and subsequently reduced ATP production, which, in turn, severely impaired macrophages mycobactericidal activity by inhibiting autophagy. Impairment of mycobactericidal activity and autophagy was replicated using oligomycin, an inhibitor of ATP synthase. In summary, our study revealed MFN1-mediated mitochondrial fusion is essential for macrophages mycobactericidal activity through the regulation of ATP dependent autophagy. MFN1-mediated metabolism pathway might be targets for development of host direct therapy (HDT) strategy against TB.
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8
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Effect of Reactive Oxygen Species on the Endoplasmic Reticulum and Mitochondria during Intracellular Pathogen Infection of Mammalian Cells. Antioxidants (Basel) 2021; 10:antiox10060872. [PMID: 34071633 PMCID: PMC8229183 DOI: 10.3390/antiox10060872] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/24/2021] [Accepted: 05/24/2021] [Indexed: 02/06/2023] Open
Abstract
Oxidative stress, particularly reactive oxygen species (ROS), are important for innate immunity against pathogens. ROS directly attack pathogens, regulate and amplify immune signals, induce autophagy and activate inflammation. In addition, production of ROS by pathogens affects the endoplasmic reticulum (ER) and mitochondria, leading to cell death. However, it is unclear how ROS regulate host defense mechanisms. This review outlines the role of ROS during intracellular pathogen infection, mechanisms of ROS production and regulation of host defense mechanisms by ROS. Finally, the interaction between microbial pathogen-induced ROS and the ER and mitochondria is described.
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9
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Clayton SA, MacDonald L, Kurowska-Stolarska M, Clark AR. Mitochondria as Key Players in the Pathogenesis and Treatment of Rheumatoid Arthritis. Front Immunol 2021; 12:673916. [PMID: 33995417 PMCID: PMC8118696 DOI: 10.3389/fimmu.2021.673916] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/12/2021] [Indexed: 12/22/2022] Open
Abstract
Mitochondria are major energy-producing organelles that have central roles in cellular metabolism. They also act as important signalling hubs, and their dynamic regulation in response to stress signals helps to dictate the stress response of the cell. Rheumatoid arthritis is an inflammatory and autoimmune disease with high prevalence and complex aetiology. Mitochondrial activity affects differentiation, activation and survival of immune and non-immune cells that contribute to the pathogenesis of this disease. This review outlines what is known about the role of mitochondria in rheumatoid arthritis pathogenesis, and how current and future therapeutic strategies can function through modulation of mitochondrial activity. We also highlight areas of this topic that warrant further study. As producers of energy and of metabolites such as succinate and citrate, mitochondria help to shape the inflammatory phenotype of leukocytes during disease. Mitochondrial components can directly stimulate immune receptors by acting as damage-associated molecular patterns, which could represent an initiating factor for the development of sterile inflammation. Mitochondria are also an important source of intracellular reactive oxygen species, and facilitate the activation of the NLRP3 inflammasome, which produces cytokines linked to disease symptoms in rheumatoid arthritis. The fact that mitochondria contain their own genetic material renders them susceptible to mutation, which can propagate their dysfunction and immunostimulatory potential. Several drugs currently used for the treatment of rheumatoid arthritis regulate mitochondrial function either directly or indirectly. These actions contribute to their immunomodulatory functions, but can also lead to adverse effects. Metabolic and mitochondrial pathways are attractive targets for future anti-rheumatic drugs, however many questions still remain about the precise role of mitochondrial activity in different cell types in rheumatoid arthritis.
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Affiliation(s)
- Sally A Clayton
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, United Kingdom.,Research into Inflammatory Arthritis Centre Versus Arthritis (RACE), Birmingham, United Kingdom
| | - Lucy MacDonald
- Research into Inflammatory Arthritis Centre Versus Arthritis (RACE), Glasgow, United Kingdom.,Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Mariola Kurowska-Stolarska
- Research into Inflammatory Arthritis Centre Versus Arthritis (RACE), Glasgow, United Kingdom.,Institute of Infection, Immunity, and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Andrew R Clark
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, United Kingdom.,Research into Inflammatory Arthritis Centre Versus Arthritis (RACE), Birmingham, United Kingdom
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10
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Patrick KL, Watson RO. Mitochondria: Powering the Innate Immune Response to Mycobacterium tuberculosis Infection. Infect Immun 2021; 89:e00687-20. [PMID: 33558322 PMCID: PMC8090963 DOI: 10.1128/iai.00687-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Within the last decade, we have learned that damaged mitochondria activate many of the same innate immune pathways that evolved to sense and respond to intracellular pathogens. These shared responses include cytosolic nucleic acid sensing and type I interferon (IFN) expression, inflammasome activation that leads to pyroptosis, and selective autophagy (called mitophagy when mitochondria are the cargo). Because mitochondria were once bacteria, parallels between how cells respond to mitochondrial and bacterial ligands are not altogether surprising. However, the potential for cross talk or synergy between bacterium- and mitochondrion-driven innate immune responses during infection remains poorly understood. This interplay is particularly striking, and intriguing, in the context of infection with the intracellular bacterial pathogen Mycobacterium tuberculosis (Mtb). Multiple studies point to a role for Mtb infection and/or specific Mtb virulence factors in disrupting the mitochondrial network in macrophages, leading to metabolic changes and triggering potent innate immune responses. Research from our laboratories and others argues that mutations in mitochondrial genes can exacerbate mycobacterial disease severity by hyperactivating innate responses or activating them at the wrong time. Indeed, growing evidence supports a model whereby different mitochondrial defects or mutations alter Mtb infection outcomes in distinct ways. By synthesizing the current literature in this minireview, we hope to gain insight into the molecular mechanisms driving, and consequences of, mitochondrion-dependent immune polarization so that we might better predict tuberculosis patient outcomes and develop host-directed therapeutics designed to correct these imbalances.
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Affiliation(s)
- Kristin L Patrick
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health, College of Medicine, Bryan, Texas, USA
| | - Robert O Watson
- Department of Microbial Pathogenesis and Immunology, Texas A&M Health, College of Medicine, Bryan, Texas, USA
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11
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Choudhuri S, Chowdhury IH, Garg NJ. Mitochondrial Regulation of Macrophage Response Against Pathogens. Front Immunol 2021; 11:622602. [PMID: 33679710 PMCID: PMC7925834 DOI: 10.3389/fimmu.2020.622602] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 12/29/2020] [Indexed: 12/18/2022] Open
Abstract
Innate immune cells play the first line of defense against pathogens. Phagocytosis or invasion by pathogens can affect mitochondrial metabolism in macrophages by diverse mechanisms and shape the macrophage response (proinflammatory vs. immunomodulatory) against pathogens. Besides β-nicotinamide adenine dinucleotide 2'-phosphate, reduced (NADPH) oxidase, mitochondrial electron transport chain complexes release superoxide for direct killing of the pathogen. Mitochondria that are injured are removed by mitophagy, and this process can be critical for regulating macrophage activation. For example, impaired mitophagy can result in cytosolic leakage of mitochondrial DNA (mtDNA) that can lead to activation of cGAS-STING signaling pathway of macrophage proinflammatory response. In this review, we will discuss how metabolism, mtDNA, mitophagy, and cGAS-STING pathway shape the macrophage response to infectious agents.
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Affiliation(s)
- Subhadip Choudhuri
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), Galveston, TX, United States
| | - Imran Hussain Chowdhury
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), Galveston, TX, United States
| | - Nisha Jain Garg
- Department of Microbiology and Immunology, University of Texas Medical Branch (UTMB), Galveston, TX, United States
- Institute for Human Infections and Immunity, UTMB, Galveston, TX, United States
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12
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Zhao H, Lin J, Sieck G, Haddad GG. Neuroprotective Role of Akt in Hypoxia Adaptation in Andeans. Front Neurosci 2021; 14:607711. [PMID: 33519361 PMCID: PMC7843528 DOI: 10.3389/fnins.2020.607711] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/11/2020] [Indexed: 11/13/2022] Open
Abstract
Chronic mountain sickness (CMS) is a disease that potentially threatens a large segment of high-altitude populations during extended living at altitudes above 2,500 m. Patients with CMS suffer from severe hypoxemia, excessive erythrocytosis and neurologic deficits. The cellular mechanisms underlying CMS neuropathology remain unknown. We previously showed that iPSC-derived CMS neurons have altered mitochondrial dynamics and increased susceptibility to hypoxia-induced cell death. Genome analysis from the same population identified many ER stress-related genes that play an important role in hypoxia adaptation or lack thereof. In the current study, we showed that iPSC-derived CMS neurons have increased expression of ER stress markers Grp78 and XBP1s under normoxia and hyperphosphorylation of PERK under hypoxia, alleviating ER stress does not rescue the hypoxia-induced CMS neuronal cell death. Akt is a cytosolic regulator of ER stress with PERK as a direct target of Akt. CMS neurons exhibited lack of Akt activation and lack of increased Parkin expression as compared to non-CMS neurons under hypoxia. By enhancing Akt activation and Parkin overexpression, hypoxia-induced CMS neuronal cell death was reduced. Taken together, we propose that increased Akt activation protects non-CMS from hypoxia-induced cell death. In contrast, impaired adaptive mechanisms including failure to activate Akt and increase Parkin expression render CMS neurons more susceptible to hypoxia-induced cell death.
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Affiliation(s)
- Helen Zhao
- Department of Pediatrics (Respiratory Medicine), University of California, San Diego, La Jolla, CA, United States
| | - Jonathan Lin
- Department of Pathology, University of California, San Diego, La Jolla, CA, United States
- Department of Pathology, Stanford University, Stanford, CA, United States
- VA Palo Alto Healthcare System, Palo Alto, CA, United States
| | - Gary Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
| | - Gabriel G. Haddad
- Department of Pediatrics (Respiratory Medicine), University of California, San Diego, La Jolla, CA, United States
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, United States
- The Rady Children’s Hospital, San Diego, CA, United States
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13
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Silwal P, Paik S, Kim JK, Yoshimori T, Jo EK. Regulatory Mechanisms of Autophagy-Targeted Antimicrobial Therapeutics Against Mycobacterial Infection. Front Cell Infect Microbiol 2021; 11:633360. [PMID: 33828998 PMCID: PMC8019938 DOI: 10.3389/fcimb.2021.633360] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 01/08/2021] [Indexed: 01/25/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) is an intracellular pathogen causing human tuberculosis, an infectious disease that still remains as a global health problem. Autophagy, a lysosomal degradative process, has emerged as a critical pathway to restrict intracellular Mtb growth through enhancement of phagosomal maturation. Indeed, several autophagy-modulating agents show promise as host-directed therapeutics for Mtb infection. In this Review, we discuss recent progress in our understanding the molecular mechanisms underlying the action of autophagy-modulating agents to overcome the immune escape strategies mediated by Mtb. The factors and pathways that govern such mechanisms include adenosine 5'-monophosphate-activated protein kinase, Akt/mammalian TOR kinase, Wnt signaling, transcription factor EB, cathelicidins, inflammation, endoplasmic reticulum stress, and autophagy-related genes. A further understanding of these mechanisms will facilitate the development of host-directed therapies against tuberculosis as well as infections with other intracellular bacteria targeted by autophagic degradation.
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Affiliation(s)
- Prashanta Silwal
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, South Korea
- Infection Control Convergence Research Center, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Seungwha Paik
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, South Korea
- Infection Control Convergence Research Center, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Jin Kyung Kim
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, South Korea
- Infection Control Convergence Research Center, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Tamotsu Yoshimori
- Department of Genetics, Graduate School of Medicine, Osaka University, Osaka, Japan
- Department of Intracellular Membrane Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Eun-Kyeong Jo
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon, South Korea
- Infection Control Convergence Research Center, Chungnam National University School of Medicine, Daejeon, South Korea
- *Correspondence: Eun-Kyeong Jo,
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Mohareer K, Medikonda J, Vadankula GR, Banerjee S. Mycobacterial Control of Host Mitochondria: Bioenergetic and Metabolic Changes Shaping Cell Fate and Infection Outcome. Front Cell Infect Microbiol 2020; 10:457. [PMID: 33102245 PMCID: PMC7554303 DOI: 10.3389/fcimb.2020.00457] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/24/2020] [Indexed: 12/20/2022] Open
Abstract
Mitochondria, are undoubtedly critical organelle of a eukaryotic cell, which provide energy and offer a platform for most of the cellular signaling pathways that decide cell fate. The role of mitochondria in immune-metabolism is now emerging as a crucial process governing several pathological states, including infection, cancer, and diabetes. Mitochondria have therefore been a vulnerable target for several bacterial and viral pathogens to control host machinery for their survival, replication, and dissemination. Mycobacterium tuberculosis, a highly successful human pathogen, persists inside alveolar macrophages at the primary infection site, applying several strategies to circumvent macrophage defenses, including control of host mitochondria. The infection perse and specific mycobacterial factors that enter the host mitochondrial milieu perturb mitochondrial dynamics and function by disturbing mitochondrial membrane potential, shifting bioenergetics parameters such as ATP and ROS, orienting the host cell fate and thereby infection outcome. In the present review, we attempt to integrate the available information and emerging dogmas to get a holistic view of Mycobacterium tuberculosis infection vis-a-vis mycobacterial factors that target host mitochondria and changes therein in terms of morphology, dynamics, proteomic, and bioenergetic alterations that lead to a differential cell fate and immune response determining the disease outcome. We also discuss critical host factors and processes that are overturned by Mycobacterium tuberculosis, such as cAMP-mediated signaling, redox homeostasis, and lipid droplet formation. Further, we also present alternate dogmas as well as the gaps and limitations in understanding some of the present research areas, which can be further explored by understanding some critical processes during Mycobacterium tuberculosis infection and the reasons thereof. Toward the end, we propose to have a set of guidelines for pursuing investigations to maintain uniformity in terms of early and late phase, MOI of infection, infection duration and incubation periods, the strain of mycobacteria, passage numbers, and so on, which all work as probable variables toward different readouts. Such a setup would, therefore, help in the smooth integration of information across laboratories toward a better understanding of the disease and possibilities of host-directed therapy.
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Affiliation(s)
- Krishnaveni Mohareer
- Laboratory of Molecular Pathogenesis, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Jayashankar Medikonda
- Laboratory of Molecular Pathogenesis, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Govinda Raju Vadankula
- Laboratory of Molecular Pathogenesis, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Sharmistha Banerjee
- Laboratory of Molecular Pathogenesis, Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
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15
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Li R, Toan S, Zhou H. Role of mitochondrial quality control in the pathogenesis of nonalcoholic fatty liver disease. Aging (Albany NY) 2020; 12:6467-6485. [PMID: 32213662 PMCID: PMC7185127 DOI: 10.18632/aging.102972] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 03/19/2020] [Indexed: 02/07/2023]
Abstract
Nutrient oversupply and mitochondrial dysfunction play central roles in nonalcoholic fatty liver disease (NAFLD). The mitochondria are the major sites of β-oxidation, a catabolic process by which fatty acids are broken down. The mitochondrial quality control (MQC) system includes mitochondrial fission, fusion, mitophagy and mitochondrial redox regulation, and is essential for the maintenance of the functionality and structural integrity of the mitochondria. Excessive and uncontrolled production of reactive oxygen species (ROS) in the mitochondria damages mitochondrial components, including membranes, proteins and mitochondrial DNA (mtDNA), and triggers the mitochondrial pathway of apoptosis. The functionality of some damaged mitochondria can be restored by fusion with normally functioning mitochondria, but when severely damaged, mitochondria are segregated from the remaining functional mitochondrial network through fission and are eventually degraded via mitochondrial autophagy, also called as mitophagy. In this review, we describe the functions and mechanisms of mitochondrial fission, fusion, oxidative stress and mitophagy in the development and progression of NAFLD.
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Affiliation(s)
- Ruibing Li
- Department of Clinical Laboratory Medicine, The First Medical Center, Chinese PLA General Hospital, Beijing 100853, China
| | - Sam Toan
- Department of Chemical Engineering, University of Minnesota-Duluth, Duluth, MN 55812, USA
| | - Hao Zhou
- Medical School of Chinese PLA, Chinese PLA General Hospital, Beijing 100853, China
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