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Xu N, Fan L, Li L, Guo Y. Exploring the pathogenicity of Mycoplasma pneumoniae: Focus on community-acquired respiratory distress syndrome toxins. Microb Pathog 2024; 195:106865. [PMID: 39153578 DOI: 10.1016/j.micpath.2024.106865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 08/12/2024] [Accepted: 08/14/2024] [Indexed: 08/19/2024]
Abstract
Community-Acquired Respiratory Distress Syndrome Toxin (CARDS TX) is a unique exotoxin produced by Mycoplasma pneumoniae (MP) and has been confirmed to possess ADP-ribosyltransferase (ART) and vacuolating activities. CARDS TX binds to receptors on the surfaces of mammalian cells followed by entry into the cells through clathrin-mediated endocytosis, and exerts cytotoxic effects by undergoing retrograde transport and finally cleavage on endosomes and cellular organelles. In addition, CARDS TX can trigger severe inflammatory reactions resulting in airway dysfunction, producing allergic inflammation and asthma-like conditions. As a newly discovered virulence factor of MP, CARDS TX has been extensively studied in recent years. As resistance to macrolide drugs has increased significantly in recent years and there is no vaccine against MP, the development of a vaccine targeting CARDS TX is considered a potential preventive measure. This review focuses on recent studies and insights into this toxin, providing directions for a better understanding of MP pathogenesis and treatment. IMPORTANCE: A serious hazard to worldwide public health in recent years, Mycoplasma pneumoniae (MP) is a prominent bacterium that causes community-acquired pneumonia (CAP) in hospitalized children. Due to their high prevalence and fatality rates, MP infections often cause both respiratory illnesses and extensive extrapulmonary symptoms. It has recently been shown that MP produces a distinct exotoxin known as Community-Acquired Respiratory Distress Syndrome Toxin (CARDS TX). Mycoplasma pneumoniae pneumonia (MPP)-like tissue injury is caused by this toxin because it has both ADP-ribosyltransferase and vacuolating properties. A better knowledge of MP etiology and therapy is provided by this review, which focuses on latest research and insights into this toxin.
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Affiliation(s)
- Nuo Xu
- Department of Respiratory Medicine, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi Children's Hospital, Wuxi, 214000, China
| | - Lu Fan
- Department of Respiratory Medicine & Clinical Allergy Center, Affiliated Children's Hospital of Jiangnan University (Wuxi Children's Hospital), Wuxi, 214000, China
| | - Ling Li
- Department of Respiratory Medicine, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi Children's Hospital, Wuxi, 214000, China; Department of Respiratory Medicine & Clinical Allergy Center, Affiliated Children's Hospital of Jiangnan University (Wuxi Children's Hospital), Wuxi, 214000, China.
| | - Yun Guo
- Department of Respiratory Medicine, The Affiliated Wuxi People's Hospital of Nanjing Medical University, Wuxi Children's Hospital, Wuxi, 214000, China; Department of Respiratory Medicine & Clinical Allergy Center, Affiliated Children's Hospital of Jiangnan University (Wuxi Children's Hospital), Wuxi, 214000, China.
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2
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Gan T, Yu J, He J. miRNA, lncRNA and circRNA: targeted molecules with therapeutic promises in Mycoplasma pneumoniae infection. Arch Microbiol 2023; 205:293. [PMID: 37477725 DOI: 10.1007/s00203-023-03636-3] [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: 05/22/2023] [Revised: 07/02/2023] [Accepted: 07/11/2023] [Indexed: 07/22/2023]
Abstract
Mycoplasma pneumoniae (MP) is primarily recognized as a respiratory pathogen that causes community-acquired pneumonia, which can lead to acute upper and lower airway inflammation and extrapulmonary syndrome. Refractory pneumonia caused by MP can cause severe complications and even be life-threatening, particularly in infants and the elderly. It is well-known that non-coding RNAs (ncRNAs) represented by miRNAs, lncRNAs and circRNAs have been manifested to be widely involved in the regulation of gene expression. Growing evidence indicates that these ncRNAs have distinct differentiated expression in MP infection and affect multiple biological processes, playing an indispensable role in the initiation and promotion of MP infection. However, the epigenetic mechanisms involved in the development of MP infection remain unclear. This article reviews the mechanisms by which miRNAs, lncRNAs, and circRNAs mediate MP infection, such as inflammatory responses, apoptosis and pulmonary fibrosis. Focusing on miRNAs, lncRNAs and circRNAs associated with MP infection could provide new insights into this disease's early diagnosis and therapeutic approaches.
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Affiliation(s)
- Tian Gan
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Jianwei Yu
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
- Department of Public Health Laboratory Sciences, School of Public Health, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Jun He
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China.
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3
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Chaurasia R, Vinetz JM. In silico prediction of molecular mechanisms of toxicity mediated by the leptospiral PF07598 gene family-encoded virulence-modifying proteins. Front Mol Biosci 2023; 9:1092197. [PMID: 36756251 PMCID: PMC9900628 DOI: 10.3389/fmolb.2022.1092197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/20/2022] [Indexed: 01/24/2023] Open
Abstract
Mechanisms of leptospirosis pathogenesis remain unclear despite the identification of a number of potential leptospiral virulence factors. We recently demonstrated potential mechanisms by which the virulence-modifying (VM) proteins-defined as containing a Domain of Unknown function (DUF1561), encoded by the PF07598 gene family-found only in group 1 pathogenic Leptospira-might mediate the clinical pathogenesis of leptospirosis. VM proteins belongs to classical AB toxin paradigm though have a unique AB domain architecture, unlike other AB toxins such as diphtheria toxin, pertussis toxin, shiga toxin, or ricin toxin which are typically encoded by two or more genes and self-assembled into a multi-domain holotoxin. Leptospiral VM proteins are secreted R-type lectin domain-containing exotoxins with discrete N-terminal ricin B-like domains involved in host cell surface binding, and a C-terminal DNase/toxin domain. Here we use the artificial intelligence-based AlphaFold algorithm and other computational tools to predict and elaborate on details of the VM protein structure-function relationship. Comparative AlphaFold and CD-spectroscopy defined the consistent secondary structure (Helix and ß-sheet) content, and the stability of the functional domains were further supported by molecular dynamics simulation. VM proteins comprises distinctive lectic family (QxW)3 motifs, the Mycoplasma CARDS toxin (D3 domain, aromatic patches), C-terminal similarity with mammalian DNase I. In-silico study proposed that Gln412, Gln523, His533, Thr59 are the high binding energy or ligand binding residues plausibly anticipates in the functional activities. Divalent cation (Mg+2-Gln412) and phosphate ion (PO4]-3-Arg615) interaction further supports the functional activities driven by C-terminal domain. Computation-driven structure-function studies of VM proteins will guide experimentation towards mechanistic understandings of leptospirosis pathogenesis, which underlie development of new therapeutic and preventive measures for this devastating disease.
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Shi J, Ma C, Hao X, Luo H, Li M. Reserve of Wnt/β-catenin Signaling Alleviates Mycoplasma pneumoniae P1-C-induced Inflammation in airway epithelial cells and lungs of mice. Mol Immunol 2023; 153:60-74. [PMID: 36444819 DOI: 10.1016/j.molimm.2022.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 10/13/2022] [Accepted: 11/02/2022] [Indexed: 11/26/2022]
Abstract
Mycoplasma pneumoniae (M. pneumoniae) is the most common pathogen of respiratory tract infections in both children and adults. M. pneumoniae P1 adhesin plays an important role in the pathogenesis of M. pneumoniae infection by mediating the attachment of pathogen to host cells. The inoculation of C-terminal residuals of P1 (P1-C) showed a protective role from M. pneumoniae infection. Accumulated evidence suggests that the Wnt/β-Catenin signaling is implicated in regulation of inflammatory responses to bacterial infections. However, mechanisms underlying the regulatory roles of Wnt signaling in host cells in response to M. pneumoniae infections are incompletely understood. In the present study, the impact and molecular mechanism of Wnt/β-catenin signaling in immune responses induced by M. pneumoniae P1-C were investigated. The results demonstrated that the P1-C could activate Wnt/β-catenin and Toll-like receptor (TLR) signaling in primary mouse airway epithelial cells cultured in an air-liquid interface (ALI) state. Interestingly, the inhibition of Wnt/β-catenin signaling by an adenovirus-mediated Wnt inhibitor Dickkopf-1 (Dkk1) gene transduction alleviated the P1-C induced inflammation fibrosis in mouse lung, accompanied by the reduced expression of epithelial mesenchymal transition (EMT) markers. Mechanistical analysis further demonstrated that the Dkk1 could suppress the expression of JAK2/STAT1-STAT3 and Caspase3, 8/Bax signaling in mouse lung tissues. In vitro study further revealed that XAV939, a small molecule of Wnt/β-catenin inhibitor, inhibited the P1-C-activated TLR4/MyD88 signaling and cytokine productions in primary mouse airway ALI epithelial cells. This study thus provides an insight into the function of Wnt/β-catenin signaling in regulation of the pathogenesis of M. pneumoniae infection, suggesting that targeting Wnt/β-catenin signaling by gene transduction of Dkk1, or pharmacological molecules of inhibitor may be a promised approach that worthy of further investigation in the treatment of M. pneumoniae pneumonia.
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Affiliation(s)
- Juan Shi
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources of Western China, College of Life Science, Ningxia University, Yinchuan, Ningxia, China; Department of Ningxia Key Laboratory of Clinical Pathogenic Microbiology, General Hospital of Ningxia Medical University, Yinchuan, Ningxia, China
| | - Chunji Ma
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources of Western China, College of Life Science, Ningxia University, Yinchuan, Ningxia, China
| | - Xiujing Hao
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources of Western China, College of Life Science, Ningxia University, Yinchuan, Ningxia, China
| | - Haixia Luo
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources of Western China, College of Life Science, Ningxia University, Yinchuan, Ningxia, China
| | - Min Li
- Key Laboratory of Ministry of Education for Conservation and Utilization of Special Biological Resources of Western China, College of Life Science, Ningxia University, Yinchuan, Ningxia, China.
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5
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Yoshikawa E, Tamiya S, Inoue Y, Suzuki K, Yoshioka Y. Vaccine using community-acquired respiratory distress syndrome toxin as an antigen against Mycoplasma pneumoniae in mice. Biochem Biophys Res Commun 2022; 594:81-87. [PMID: 35078111 DOI: 10.1016/j.bbrc.2022.01.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 01/14/2022] [Indexed: 11/02/2022]
Abstract
Mycoplasma pneumoniae (Mp) is one of the most common causes of bacterial community-acquired pneumonia in humans. Because of the frequent epidemics and the emergence of antibiotic-resistant Mp, vaccines for Mp are urgently needed to ameliorate the pneumonia and secondary complications. The community-acquired respiratory distress syndrome (CARDS) toxin produced by Mp is a pathogenic factor that induces severe inflammatory responses in lung. Although blocking CARDS toxin is expected to mitigate the severity of Mp pneumonia, the potential of CARDS toxin as a vaccine antigen has not been assessed. Here, we examined the effectiveness of vaccine using recombinant CARDS toxin (rCARDS toxin) as an antigen in mice. Immunization with rCARDS toxin induced both rCARDS toxin- and Mp-specific antibody responses, indicating that CARDS toxin is located on the surface of Mp. In addition, immunization with rCARDS toxin decreased not only lung injury, neutrophil infiltration, and the production of inflammatory cytokines but also the persistence of Mp in lung after Mp challenge. Furthermore, we elucidated that the CARDS toxin on the surface of Mp facilitates the adherence of Mp to epithelial cells. In conclusion, we have demonstrated the potential of rCARDS toxin as a vaccine antigen to ameliorate Mp pneumonia by suppressing the inflammatory responses induced by Mp and the persistence of Mp in lung. These data support the development of novel vaccines for Mp pneumonia.
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Affiliation(s)
- Eisuke Yoshikawa
- Laboratory of Nano-design for Innovative Drug Development, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan; Vaccine Creation Group, BIKEN Innovative Vaccine Research Alliance Laboratories, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shigeyuki Tamiya
- Laboratory of Nano-design for Innovative Drug Development, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan; Vaccine Creation Group, BIKEN Innovative Vaccine Research Alliance Laboratories, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yuji Inoue
- The Research Foundation for Microbial Diseases of Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Koichiro Suzuki
- The Research Foundation for Microbial Diseases of Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yasuo Yoshioka
- Laboratory of Nano-design for Innovative Drug Development, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan; Vaccine Creation Group, BIKEN Innovative Vaccine Research Alliance Laboratories, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan; The Research Foundation for Microbial Diseases of Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan; Vaccine Creation Group, BIKEN Innovative Vaccine Research Alliance Laboratories, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan; Global Center for Medical Engineering and Informatics, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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6
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Su X, You X, Luo H, Liang K, Chen L, Tian W, Ye Z, He J. Community-Acquired Respiratory Distress Syndrome Toxin: Unique Exotoxin for M. pneumoniae. Front Microbiol 2021; 12:766591. [PMID: 34867898 PMCID: PMC8640204 DOI: 10.3389/fmicb.2021.766591] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/19/2021] [Indexed: 11/13/2022] Open
Abstract
Mycoplasma pneumoniae infection often causes respiratory diseases in humans, particularly in children and adults with atypical pneumonia and community-acquired pneumonia (CAP), and is often exacerbated by co-infection with other lung diseases, such as asthma, bronchitis, and chronic obstructive pulmonary disorder. Community-acquired respiratory distress syndrome toxin (CARDS TX) is the only exotoxin produced by M. pneumoniae and has been extensively studied for its ADP-ribosyltransferase (ADPRT) activity and cellular vacuolization properties. Additionally, CARDS TX induces inflammatory responses, resulting in cell swelling, nuclear lysis, mucus proliferation, and cell vacuolization. CARDS TX enters host cells by binding to the host receptor and is then reverse transported to the endoplasmic reticulum to exert its pathogenic effects. In this review, we focus on the structural characteristics, functional activity, distribution and receptors, mechanism of cell entry, and inflammatory response of CARDS TX was examined. Overall, the findings of this review provide a theoretical basis for further investigation of the mechanism of M. pneumoniae infection and the development of clinical diagnosis and vaccines.
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Affiliation(s)
- Xiaoling Su
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, 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
| | - Haodang Luo
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, China
| | - Keying Liang
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, China
| | - Li Chen
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, China
| | - Wei Tian
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, China
| | - Zufeng Ye
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, China
| | - Jun He
- The Affiliated Nanhua Hospital, Department of Clinical Laboratory, Hengyang Medical School, University of South China, Hengyang, China
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7
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Kellner A, Cherubin P, Harper JK, Teter K. Proline Isomerization as a Key Determinant for Hsp90-Toxin Interactions. Front Cell Infect Microbiol 2021; 11:771653. [PMID: 34746036 PMCID: PMC8569296 DOI: 10.3389/fcimb.2021.771653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 10/05/2021] [Indexed: 11/30/2022] Open
Abstract
The A chains of ADP-ribosylating toxins exploit Hsp90 for translocation into the host cytosol. Here, we hypothesize that cis proline residues play a key role in toxin recognition by Hsp90. Our model is largely derived from studies on the unusual interplay between Hsp90 and the catalytic A1 subunit of cholera toxin (CTA1), including the recent identification of an RPPDEI-like binding motif for Hsp90 in CTA1 and several other bacterial toxins. Cis/trans proline isomerization is known to influence protein-protein interactions and protein structure/function, but it has not yet been proposed to affect Hsp90-toxin interactions. Our model thus provides a new framework to understand the molecular basis for Hsp90 chaperone function and Hsp90-driven toxin translocation.
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Affiliation(s)
- Alisha Kellner
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
| | - Patrick Cherubin
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
| | - James K Harper
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, United States
| | - Ken Teter
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
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Ramasamy K, Balasubramanian S, Kirkpatrick A, Szabo D, Pandranki L, Baseman JB, Kannan TR. Mycoplasma pneumoniae CARDS toxin exploits host cell endosomal acidic pH and vacuolar ATPase proton pump to execute its biological activities. Sci Rep 2021; 11:11571. [PMID: 34078958 PMCID: PMC8172646 DOI: 10.1038/s41598-021-90948-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 05/19/2021] [Indexed: 11/09/2022] Open
Abstract
Mycoplasma pneumoniae is the leading cause of bacterial community-acquired pneumonia among hospitalized children in the United States. It is also responsible for a spectrum of other respiratory tract disorders and extrapulmonary manifestations in children and adults. The main virulence factor of M. pneumoniae is a 591 amino acid multifunctional protein called Community Acquired Respiratory Distress Syndrome (CARDS) toxin. The amino terminal region of CARDS toxin (N-CARDS) retains ADP-ribosylating activity and the carboxy region (C-CARDS) contains the receptor binding and vacuolating activities. After internalization, CARDS toxin is transported in a retrograde manner from endosome through the Golgi complex into the endoplasmic reticulum. However, the mechanisms and criteria by which internalized CARDS toxin is transported and activated to execute its cytotoxic effects remain unknown. In this study, we used full-length CARDS toxin and its mutant and truncated derivatives to analyze how pharmacological drugs that alter pH of intracellular vesicles and electrical potential across vesicular membranes affect translocation of CARDS toxin in mammalian cells. Our results indicate that an acidic environment is essential for CARDS toxin retrograde transport to endoplasmic reticulum. Moreover, retrograde transport facilitates toxin clipping and is required to induce vacuole formation. Additionally, toxin-mediated cell vacuolation is strictly dependent on the function of vacuolar type-ATPase.
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Affiliation(s)
- Kumaraguruparan Ramasamy
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health San Antonio, San Antonio, TX, 78229, USA
| | - Sowmya Balasubramanian
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health San Antonio, San Antonio, TX, 78229, USA
| | - Alejandra Kirkpatrick
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health San Antonio, San Antonio, TX, 78229, USA
| | - Daniel Szabo
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health San Antonio, San Antonio, TX, 78229, USA
| | - Lavanya Pandranki
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health San Antonio, San Antonio, TX, 78229, USA
| | - Joel B Baseman
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health San Antonio, San Antonio, TX, 78229, USA
| | - T R Kannan
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health San Antonio, San Antonio, TX, 78229, USA.
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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: 21] [Impact Index Per Article: 7.0] [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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10
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Zhao F, Liu J, Xiao D, Liu L, Gong J, Xu J, Li H, Zhao S, Zhang J. Pathogenic Analysis of the Bronchoalveolar Lavage Fluid Samples With Pediatric Refractory Mycoplasma pneumoniae Pneumonia. Front Cell Infect Microbiol 2020; 10:553739. [PMID: 33194797 PMCID: PMC7655529 DOI: 10.3389/fcimb.2020.553739] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/23/2020] [Indexed: 01/04/2023] Open
Abstract
Background: We conducted a pathogenic analysis in the bronchoalveolar lavage fluid (BALF) samples from refractory Mycoplasma pneumoniae pneumonia (RMPP) children. Methods: A total of 150 BALF samples from 60 RMPP patients were analyzed to investigate pathogenic changes. The characteristics of M. pneumoniae were analyzed through culture, real-time PCR, genotyping, antimicrobial susceptibility testing and proteomics. The other pathogens were determined using culture, sequencing and nucleic acid detection. Results: In 60 RMPP cases, the bacterial co-infection rate was 5%, while that of virus was 33.3%. The poor prognosis rate was 61.7%. The DNA positive rate among the 150 samples was 98.7%, while the culture positive rate was 56.7% for M. pneumoniae. Significant differences were noticed in the positivity of M. pneumoniae culture obtained from samples with a disease course of at least 3 weeks compared with those within 3 weeks. The genotype 1 M. pneumoniae strains showed a macrolide resistant (MLr) rate of 100%, and that for genotype 2 was 90.1%. Proteomics showed that there were 57 proteins up-regulated in the MLs M. pneumoniae, half of which were membrane-associated protein with adhesion or toxicity. Conclusions: Pediatric RMPP usually presented with viral co-infection, but it caused limited effects on the progression and prognosis of RMPP. Persistent presence of viable M. pneumoniae is not necessary in the later stage of RMPP. The expression of virulence factor in the MLr M. pneumoniae was higher than that of the MLs M. pneumoniae, which was more common in the RMPP children.
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Affiliation(s)
- Fei Zhao
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China
| | - Jinrong Liu
- Department of Respiratory Medicine, Beijing Children's Hospital Affiliated to Capital Medical University, National Center for Children's Health, Beijing, China
| | - Di Xiao
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China
| | - Liyong Liu
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China
| | - Jie Gong
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China
| | - Juan Xu
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China
| | - Huimin Li
- Department of Respiratory Medicine, Beijing Children's Hospital Affiliated to Capital Medical University, National Center for Children's Health, Beijing, China
| | - Shunying Zhao
- Department of Respiratory Medicine, Beijing Children's Hospital Affiliated to Capital Medical University, National Center for Children's Health, Beijing, China
| | - Jianzhong Zhang
- National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Beijing, China
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11
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Luo H, He J, Qin L, Chen Y, Chen L, Li R, Zeng Y, Zhu C, You X, Wu Y. Mycoplasma pneumoniae lipids license TLR-4 for activation of NLRP3 inflammasome and autophagy to evoke a proinflammatory response. Clin Exp Immunol 2020; 203:66-79. [PMID: 32894580 DOI: 10.1111/cei.13510] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/15/2020] [Accepted: 08/21/2020] [Indexed: 12/23/2022] Open
Abstract
Mycoplasma pneumoniae is an obligate pathogen that causes pneumonia, tracheobronchitis, pharyngitis and asthma in humans. It is well recognized that membrane lipoproteins are immunostimulants exerting as lipopolysaccharides (LPS) and play a crucial role in the pathogenesis of inflammatory responses upon M. pneumoniae infection. Here, we report that the M. pneumoniae-derived lipids are another proinflammatory agents. Using an antibody-neutralizing assay, RNA interference or specific inhibitors, we found that Toll-like receptor 4 (TLR-4) is essential for M. pneumoniae lipid-induced tumour necrosis factor (TNF)-α and interleukin (IL)-1β production. We also demonstrate that NLR family pyrin domain containing 3 inflammasome (NLRP3) inflammasome, autophagy and nuclear factor kappa B (NF-κB)-dependent pathways are critical for the secretion of proinflammatory cytokines, while inhibition of TLR-4 significantly abrogates these events. Further characterization revealed that autophagy-mediated inflammatory responses involved the activation of NF-κB. In addition, the activation of NF-κB promoted lipid-induced autophagosome formation, as revealed by assays using pharmacological inhibitors, 3-methyladenine (3-MA) and Bay 11-7082, or silencing of atg5 and beclin-1. These findings suggest that, unlike the response to lipoprotein stimulation, the inflammation in response to M. pneumoniae lipids is mediated by the TLR-4 pathway, which subsequently initiates the activation of NLRP3 inflammasome and formation of a positive feedback loop between autophagy and NF-κB signalling cascade, ultimately promoting TNF-α and Il-1β production in macrophages.
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Affiliation(s)
- H Luo
- 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.,Department of Clinical Laboratory, The Affiliated Nanhua Hospital of University of South China, Hengyang, China
| | - J He
- Department of Clinical Laboratory, The Affiliated Nanhua Hospital of University of South China, Hengyang, China
| | - L Qin
- 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
| | - Y Chen
- 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
| | - L Chen
- 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
| | - R Li
- 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
| | - Y Zeng
- 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
| | - C Zhu
- 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
| | - X You
- 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
| | - Y Wu
- 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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12
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Li G, Fan L, Wang Y, Huang L, Wang M, Zhu C, Hao C, Ji W, Liang H, Yan Y, Chen Z. High co-expression of TNF-α and CARDS toxin is a good predictor for refractory Mycoplasma pneumoniae pneumonia. Mol Med 2019; 25:38. [PMID: 31399022 PMCID: PMC6688229 DOI: 10.1186/s10020-019-0105-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 07/23/2019] [Indexed: 11/25/2022] Open
Abstract
Background Early distinction between refractory M. pneumoniae pneumonia (RMPP) and non-RMPP (NRMPP) is still difficult. The community-acquired respiratory distress syndrome (CARDS) toxin can induce inflammatory and histopathological phenotypes associated with M. pneumoniae infection. This study aimed to investigate the clinical significance of CARDS toxin and pro-inflammatory cytokines in children with RMPP and to explore whether CARDS toxin can induce TNF-α expression. Methods Levels of CARDS toxin and cytokines in BALF from control and children with MPP were determined by real-time PCR and ELISA, respectively. A receiver-operating characteristic (ROC) analysis was performed to assess the diagnostic values of CARDS toxin, TNF-α, and IL-6 in RMPP. The recombinant CARDS toxin was constructed and prepared at different concentrations for stimulation of RAW264.7 cells. After co-culture with CARDS toxin, cytokines were detected by ELISA and the mRNA levels were measured by real-time PCR. Effects of CARDS toxin and TNF-α on inflammatory cell infiltration and mucus secretion in mouse lungs were also evaluated. Results Levels of CARDS toxin, TNF-α and IL-6 in bronchoalveolar lavage fluid (BALF) were significantly higher in RMPP cases compared with NRMPP cases. Furthermore, TNF-α had better diagnostic ability for differentiation of RMPP with AUC of 0.824 and Youden index of 0.692 compared with CARDS toxin and IL-6. Moreover, CARDS toxin was positively correlated with TNF-α level in MPP cases. In vitro assay revealed that CARDS toxin induced RAW264.7 macrophages to secrete TNF-α. Further in vivo assay showed that TNF-α deletion partially abrogated the CARDS toxin-mediated induction of inflammatory cell infiltration and mucus secretion in mouse lungs. Conclusions The high co-expression of TNF-α and CARDS toxin in BALF is a good diagnostic biomarker for differentiating children with RMPP and NRMPP.
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Affiliation(s)
- Gang Li
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Liping Fan
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Yuqing Wang
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Li Huang
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Meijuan Wang
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Canhong Zhu
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Chuangli Hao
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Wei Ji
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Hansi Liang
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China
| | - Yongdong Yan
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China.
| | - Zhengrong Chen
- Department of Respiratory medicine, Children's Hospital of Soochow University, Jingde Road NO.303, Suzhou, 215003, Jiangsu Province, China.
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13
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Balasubramanian S, Pandranki L, Maupin S, Ramasamy K, Taylor AB, Hart PJ, Baseman JB, Kannan TR. Disulfide bond of Mycoplasma pneumoniae community-acquired respiratory distress syndrome toxin is essential to maintain the ADP-ribosylating and vacuolating activities. Cell Microbiol 2019; 21:e13032. [PMID: 30977272 DOI: 10.1111/cmi.13032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/19/2019] [Accepted: 04/03/2019] [Indexed: 01/13/2023]
Abstract
Mycoplasma pneumoniae is the leading cause of bacterial community-acquired pneumonia among hospitalised children in United States and worldwide. Community-acquired respiratory distress syndrome (CARDS) toxin is a key virulence determinant of M. pneumoniae. The N-terminus of CARDS toxin exhibits ADP-ribosyltransferase (ADPRT) activity, and the C-terminus possesses binding and vacuolating activities. Thiol-trapping experiments of wild-type (WT) and cysteine-to-serine-mutated CARDS toxins with alkylating agents identified disulfide bond formation at the amino terminal cysteine residues C230 and C247. Compared with WT and other mutant toxins, C247S was unstable and unusable for comparative studies. Although there were no significant variations in binding, entry, and retrograde trafficking patterns of WT and mutated toxins, C230S did not elicit vacuole formation in intoxicated cells. In addition, the ADPRT domain of C230S was more sensitive to all tested proteases when compared with WT toxin. Despite its in vitro ADPRT activity, the reduction of C230S CARDS toxin-mediated ADPRT activity-associated IL-1β production in U937 cells and the recovery of vacuolating activity in the protease-released carboxy region of C230S indicated that the disulfide bond was essential not only to maintain the conformational stability of CARDS toxin but also to properly execute its cytopathic effects.
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Affiliation(s)
- Sowmya Balasubramanian
- Department of Microbiology, Immunology and Molecular Genetics, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Lavanya Pandranki
- Department of Microbiology, Immunology and Molecular Genetics, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Suzanna Maupin
- Department of Microbiology, Immunology and Molecular Genetics, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Kumaraguruparan Ramasamy
- Department of Microbiology, Immunology and Molecular Genetics, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Alexander B Taylor
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX.,X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Peter John Hart
- Department of Biochemistry and Structural Biology, The University of Texas Health Science Center at San Antonio, San Antonio, TX.,X-ray Crystallography Core Laboratory, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Joel B Baseman
- Department of Microbiology, Immunology and Molecular Genetics, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Thirumalai R Kannan
- Department of Microbiology, Immunology and Molecular Genetics, The University of Texas Health Science Center at San Antonio, San Antonio, Texas
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