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Georgakopoulou VE, Lempesis IG, Sklapani P, Trakas N, Spandidos DA. Exploring the pathogenetic mechanisms of Mycoplasmapneumoniae (Review). Exp Ther Med 2024; 28:271. [PMID: 38765654 PMCID: PMC11097136 DOI: 10.3892/etm.2024.12559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Accepted: 04/17/2024] [Indexed: 05/22/2024] Open
Abstract
Mycoplasmas, the smallest self-replicating prokaryotes without a cell wall, are the most prevalent and extensively studied species in humans. They significantly contribute to chronic respiratory tract illnesses and pneumonia, with children and adolescents being particularly vulnerable. Mycoplasma pneumoniae (M. pneumoniae) infections typically tend to be self-limiting and mild but can progress to severe or even life-threatening conditions in certain individuals. Extrapulmonary effects often occur without pneumonia, and both intrapulmonary and extrapulmonary complications operate through separate pathological mechanisms. The indirect immune-mediated damage of the immune system, vascular blockages brought on by vasculitis or thrombosis and direct harm from invasion or locally induced inflammatory cytokines are potential causes of extrapulmonary manifestations due to M. pneumoniae. Proteins associated with adhesion serve as the primary factor crucial for the pathogenicity of M. pneumoniae, relying on a specialized polarized terminal attachment organelle. The type and density of these host receptors significantly impact the adhesion and movement of M. pneumoniae, subsequently influencing the pathogenic mechanism and infection outcomes. Adjacent proteins are crucial for the proper assembly of the attachment organelle, with variations in the genetic domains of P1, P40 and P90 surfaces contributing to the variability of clinical symptoms and offering new avenues for developing vaccines against M. pneumoniae infections. M. pneumoniae causes oxidative stress within respiratory tract epithelial cells by adhering to host cells and releasing hydrogen peroxide and superoxide radicals. This oxidative stress enhances the vulnerability of host cells to harm induced by oxygen molecules. The lack of superoxide dismutase and catalase of bacteria allows it to hinder the catalase activity of the host cell, leading to the reduced breakdown of peroxides. Lung macrophages play a significant role in managing M. pneumoniae infection, identifying it via Toll-like receptor 2 and initiating the myeloid differentiation primary response gene 88-nuclear factor κΒ signaling cascade. However, the precise mechanisms enabling M. pneumoniae to evade intracellular host defenses remain unknown, necessitating further exploration of the pathways involved in intracellular survival. The present comprehensive review delves into the pathogenesis of M. pneumoniae infection within the pulmonary system and into extrapulmonary areas, outlining its impact.
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Affiliation(s)
- Vasiliki Epameinondas Georgakopoulou
- Department of Pathophysiology, Laiko General Hospital, National and Kapodisttrian University of Athens, 11527 Athens, Greece
- Department of Infectious Diseases-COVID-19 Unit, Laiko General Hospital, 11527 Athens, Greece
| | - Ioannis G. Lempesis
- Department of Pathophysiology, Laiko General Hospital, National and Kapodisttrian University of Athens, 11527 Athens, Greece
| | - Pagona Sklapani
- Department of Biochemistry, Sismanogleio Hospital, 15126 Athens, Greece
| | - Nikolaos Trakas
- Department of Biochemistry, Sismanogleio Hospital, 15126 Athens, Greece
| | - Demetrios A. Spandidos
- Laboratory of Clinical Virology, School of Medicine, University of Crete, 71003 Heraklion, Greece
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Insight into the Pathogenic Mechanism of Mycoplasma pneumoniae. Curr Microbiol 2023; 80:14. [PMID: 36459213 PMCID: PMC9716528 DOI: 10.1007/s00284-022-03103-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 10/28/2022] [Indexed: 12/04/2022]
Abstract
Mycoplasma pneumoniae, an obligate parasitic pathogen without cell wall, can cause severe upper and lower respiratory tract symptoms. It is the pathogen of human bronchitis and walking pneumonia, and named community-acquired pneumonia. In addition to severe respiratory symptoms, there are clinical extrapulmonary manifestations in the skin, brain, kidney, musculoskeletal, digestive system, and even blood system after M. pneumoniae infection. Hereby, we comprehensively summarized and reviewed the intrapulmonary and extrapulmonary pathogenesis of M. pneumoniae infection. The pathogenesis of related respiratory symptoms caused by M. pneumoniae is mainly adhesion damage, direct damage including nutrient predation, invasion and toxin, cytokine induced inflammation damage and immune evasion effect. The pathogenesis of extrapulmonary manifestations includes direct damage mediated by invasion and inflammatory factors, indirect damage caused by host immune response, and vascular occlusion. The intrapulmonary and extrapulmonary pathogenic mechanisms of M. pneumoniae infection are independent and interrelated, and have certain commonalities. In fact, the pathogenic mechanisms of M. pneumoniae are complicated, and the specific content is still not completely clear, further researches are necessary for determining the detailed pathogenesis of M. pneumoniae. This review can provide certain guidance for the effective prevention and treatment of M. pneumoniae infection.
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Qin L, Liu L, Wu Y, Chen Y, Wu Y, Luo H, Xi Y, Xiu F, Hu J, Chen L, Wu N, He J, Zeng Y, Zhu C, You X. Mycoplasma pneumoniae downregulates RECK to promote matrix metalloproteinase-9 secretion by bronchial epithelial cells. Virulence 2022; 13:1270-1284. [PMID: 35892136 PMCID: PMC9336473 DOI: 10.1080/21505594.2022.2101746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Airway epithelial cells function as both a physical barrier against harmful substances and pathogenic microorganisms and as an important participant in the innate immune system. Matrix metalloproteinase-9 (MMP-9) plays a crucial role in modulating inflammatory responses during respiratory infections. However, the signalling cascade that induces MMP-9 secretion from epithelial cells infected with Mycoplasma pneumoniae remains poorly understood. In this study, we investigated the mechanism of MMP-9 secretion in airway epithelial cells infected with M. pneumoniae. Our data clearly showed that M. pneumoniae induced the secretion of MMP-9 from bronchial epithelial cells and upregulated its enzymatic activity in a time- and dose-dependent manner. Using specific inhibitors and chromatin co-precipitation experiments, we confirmed that the expression of MMP-9 is reliant on the activation of the Toll-like receptor 2 (TLR2) and TLR6-dependent mitogen-activated protein kinase/nuclear factor- κB/activator protein-1 (MAPK/NF-κB/AP-1) pathways. Additionally, epigenetic modifications such as histone acetylation and the nuclear transcription factor Sp1 also regulate MMP-9 expression. M. pneumoniae infection also decreased the expression of the tumour suppressor reversion-inducing cysteine-rich protein with Kazal motifs (RECK) by inducing Sp1 phosphorylation. Overexpression of RECK significantly impaired the M. pneumoniae-triggered increase in MMP-9 enzymatic activity, although the level of MMP-9 protein remained constant. The study demonstrated that M. pneumoniae-triggered MMP-9 expression is modulated by TLR2 and 6, the MAPK/NF-κB/AP-1 signalling cascade, and histone acetylation, and M. pneumoniae downregulated the expression of RECK, thereby increasing MMP-9 activity to modulate the inflammatory response, which could play a role in airway remodelling.
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Affiliation(s)
- Lianmei Qin
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China.,Department of Blood Transfusion, Shenzhen Children's Hospital, Shenzhen, China
| | - Lu Liu
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Yueping Wu
- Department of Blood Transfusion, Shenzhen Children's Hospital, Shenzhen, China
| | - Yiwen Chen
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Yueyue Wu
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Haodang Luo
- Department of Clinical Laboratory, The Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Yixuan Xi
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Feichen Xiu
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Jun Hu
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Liesong Chen
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Ning Wu
- Department of Clinical Laboratory, Hengyang No.1 People's Hospital, Hengyang, China
| | - Jun He
- Department of Clinical Laboratory, The Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Yanhua Zeng
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Cuiming Zhu
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Xiaoxing You
- Institute of Pathogenic Biology, Hengyang Medical School, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
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Meireles DA, da Silva Neto JF, Domingos RM, Alegria TGP, Santos LCM, Netto LES. Ohr - OhrR, a neglected and highly efficient antioxidant system: Structure, catalysis, phylogeny, regulation, and physiological roles. Free Radic Biol Med 2022; 185:6-24. [PMID: 35452809 DOI: 10.1016/j.freeradbiomed.2022.04.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 03/09/2022] [Accepted: 04/02/2022] [Indexed: 12/24/2022]
Abstract
Ohrs (organic hydroperoxide resistance proteins) are antioxidant enzymes that play central roles in the response of microorganisms to organic peroxides. Here, we describe recent advances in the structure, catalysis, phylogeny, regulation, and physiological roles of Ohr proteins and of its transcriptional regulator, OhrR, highlighting their unique features. Ohr is extremely efficient in reducing fatty acid peroxides and peroxynitrite, two oxidants relevant in host-pathogen interactions. The highly reactive Cys residue of Ohr, named peroxidatic Cys (Cp), composes together with an arginine and a glutamate the catalytic triad. The catalytic cycle of Ohrs involves a condensation between a sulfenic acid (Cp-SOH) and the thiol of the second conserved Cys, leading to the formation of an intra-subunit disulfide bond, which is then reduced by dihydrolipoamide or lipoylated proteins. A structural switch takes place during catalysis, with the opening and closure of the active site by the so-called Arg-loop. Ohr is part of the Ohr/OsmC super-family that also comprises OsmC and Ohr-like proteins. Members of the Ohr, OsmC and Ohr-like subgroups present low sequence similarities among themselves, but share a high structural conservation, presenting two Cys residues in their active site. The pattern of gene expression is also distinct among members of the Ohr/OsmC subfamilies. The expression of ohr genes increases upon organic hydroperoxides treatment, whereas the signals for the upregulation of osmC are entry into the stationary phase and/or osmotic stress. For many ohr genes, the upregulation by organic hydroperoxides is mediated by OhrR, a Cys-based transcriptional regulator that only binds to its target DNAs in its reduced state. Since Ohrs and OhrRs are involved in virulence of some microorganisms and are absent in vertebrate and vascular plants, they may represent targets for novel therapeutic approaches based on the disruption of this key bacterial organic peroxide defense system.
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Affiliation(s)
- Diogo A Meireles
- Laboratório de Fisiologia e Bioquímica de Microrganismos (LFBM) da Universidade Estadual do Norte Fluminense Darcy Ribeiro, Brazil
| | - José F da Silva Neto
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP), Brazil
| | | | - Thiago G P Alegria
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, Brazil
| | - Lene Clara M Santos
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, Brazil
| | - Luis Eduardo S Netto
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, Brazil.
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Yiwen C, Yueyue W, Lianmei Q, Cuiming Z, Xiaoxing Y. Infection strategies of mycoplasmas: Unraveling the panoply of virulence factors. Virulence 2021; 12:788-817. [PMID: 33704021 PMCID: PMC7954426 DOI: 10.1080/21505594.2021.1889813] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Mycoplasmas, the smallest bacteria lacking a cell wall, can cause various diseases in both humans and animals. Mycoplasmas harbor a variety of virulence factors that enable them to overcome numerous barriers of entry into the host; using accessory proteins, mycoplasma adhesins can bind to the receptors or extracellular matrix of the host cell. Although the host immune system can eradicate the invading mycoplasma in most cases, a few sagacious mycoplasmas employ a series of invasion and immune escape strategies to ensure their continued survival within their hosts. For instance, capsular polysaccharides are crucial for anti-phagocytosis and immunomodulation. Invasive enzymes degrade reactive oxygen species, neutrophil extracellular traps, and immunoglobulins. Biofilm formation is important for establishing a persistent infection. During proliferation, successfully surviving mycoplasmas generate numerous metabolites, including hydrogen peroxide, ammonia and hydrogen sulfide; or secrete various exotoxins, such as community-acquired respiratory distress syndrome toxin, and hemolysins; and express various pathogenic enzymes, all of which have potent toxic effects on host cells. Furthermore, some inherent components of mycoplasmas, such as lipids, membrane lipoproteins, and even mycoplasma-generated superantigens, can exert a significant pathogenic impact on the host cells or the immune system. In this review, we describe the proposed virulence factors in the toolkit of notorious mycoplasmas to better understand the pathogenic features of these bacteria, along with their pathogenic mechanisms.
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Affiliation(s)
- Chen Yiwen
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China; Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control; Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, China
| | - Wu Yueyue
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China; Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control; Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, China
| | - Qin Lianmei
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China; Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control; Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, China
| | - Zhu Cuiming
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China; Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control; Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, China
| | - You Xiaoxing
- Institute of Pathogenic Biology, Hengyang Medical College, University of South China; Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control; Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang, China
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All living cells are cognitive. Biochem Biophys Res Commun 2020; 564:134-149. [PMID: 32972747 DOI: 10.1016/j.bbrc.2020.08.120] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/28/2020] [Accepted: 08/19/2020] [Indexed: 12/24/2022]
Abstract
All living cells sense and respond to changes in external or internal conditions. Without that cognitive capacity, they could not obtain nutrition essential for growth, survive inevitable ecological changes, or correct accidents in the complex processes of reproduction. Wherever examined, even the smallest living cells (prokaryotes) display sophisticated regulatory networks establishing appropriate adaptations to stress conditions that maximize the probability of survival. Supposedly "simple" prokaryotic organisms also display remarkable capabilities for intercellular signalling and multicellular coordination. These observations indicate that all living cells are cognitive.
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Qin L, Chen Y, You X. Subversion of the Immune Response by Human Pathogenic Mycoplasmas. Front Microbiol 2019; 10:1934. [PMID: 31497004 PMCID: PMC6712165 DOI: 10.3389/fmicb.2019.01934] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/06/2019] [Indexed: 12/17/2022] Open
Abstract
Mycoplasmas are a large group of prokaryotes which is believed to be originated from Gram-positive bacteria via degenerative evolution, and mainly capable of causing a wide range of human and animal infections. Although innate immunity and adaptive immunity play crucial roles in preventing mycoplasma infection, immune response that develops after infection fails to completely eliminate this bacterium under certain circumstances. Thus, it is reasonable to speculate that mycoplasmas employ some mechanisms to deal with coercion of host defense system. In this review, we will highlight and provide a comprehensive overview of immune evasion strategies that have emerged in mycoplasma infection, which can be divided into four aspects: (i) Molecular mimicry and antigenic variation on the surface of the bacteria to evade the immune surveillance; (ii) Overcoming the immune effector molecules assaults: Induction of detoxified enzymes to degradation of reactive oxygen species; Expression of nucleases to degrade the neutrophil extracellular traps to avoid killing by Neutrophil; Capture and cleavage of immunoglobulins to evade humoral immune response; (iii) Persistent survival: Invading into the host cell to escape the immune damage; Formation of a biofilm to establish a persistent infection; (iv) Modulation of the immune system to down-regulate the intensity of immune response. All of these features increase the probability of mycoplasma survival in the host and lead to a persistent, chronic infections. A profound understanding on the mycoplasma to subvert the immune system will help us to better understand why mycoplasma is so difficult to eradicate and ultimately provide new insights on the development of therapeutic regimens against this bacterium in future.
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Affiliation(s)
- Lianmei Qin
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Yiwen Chen
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
| | - Xiaoxing You
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, China
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