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Popoff MR. Overview of Bacterial Protein Toxins from Pathogenic Bacteria: Mode of Action and Insights into Evolution. Toxins (Basel) 2024; 16:182. [PMID: 38668607 PMCID: PMC11054074 DOI: 10.3390/toxins16040182] [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: 02/16/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/29/2024] Open
Abstract
Bacterial protein toxins are secreted by certain bacteria and are responsible for mild to severe diseases in humans and animals. They are among the most potent molecules known, which are active at very low concentrations. Bacterial protein toxins exhibit a wide diversity based on size, structure, and mode of action. Upon recognition of a cell surface receptor (protein, glycoprotein, and glycolipid), they are active either at the cell surface (signal transduction, membrane damage by pore formation, or hydrolysis of membrane compound(s)) or intracellularly. Various bacterial protein toxins have the ability to enter cells, most often using an endocytosis mechanism, and to deliver the effector domain into the cytosol, where it interacts with an intracellular target(s). According to the nature of the intracellular target(s) and type of modification, various cellular effects are induced (cell death, homeostasis modification, cytoskeleton alteration, blockade of exocytosis, etc.). The various modes of action of bacterial protein toxins are illustrated with representative examples. Insights in toxin evolution are discussed.
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Affiliation(s)
- Michel R Popoff
- Unité des Toxines Bactériennes, Institut Pasteur, Université Paris Cité, CNRS UMR 2001 INSERM U1306, F-75015 Paris, France
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Bandyopadhyay S, Zhang X, Ascura A, Edelblum KL, Bonder EM, Gao N. Salmonella engages CDC42 effector protein 1 for intracellular invasion. J Cell Physiol 2024; 239:36-50. [PMID: 37877586 DOI: 10.1002/jcp.31142] [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: 03/01/2023] [Revised: 08/25/2023] [Accepted: 10/03/2023] [Indexed: 10/26/2023]
Abstract
Human enterocytes are primary targets of infection by invasive bacterium Salmonella Typhimurium, and studies using nonintestinal epithelial cells established that S. Typhimurium activates Rho family GTPases, primarily CDC42, to modulate the actin cytoskeletal network for invasion. The host intracellular protein network that engages CDC42 and influences the pathogen's invasive capacity are relatively unclear. Here, proteomic analyses of canonical and variant CDC42 interactomes identified a poorly characterized CDC42 interacting protein, CDC42EP1, whose intracellular localization is rapidly redistributed and aggregated around the invading bacteria. CDC42EP1 associates with SEPTIN-7 and Villin, and its relocalization and bacterial engagement depend on host CDC42 and S. Typhimurium's capability of activating CDC42. Unlike CDC42, CDC42EP1 is not required for S. Typhimurium's initial cellular entry but is found to associate with Salmonella-containing vacuoles after long-term infections, indicating a contribution to the pathogen's intracellular growth and replication. These results uncover a new host regulator of enteric Salmonella infections, which may be targeted to restrict bacterial load at the primary site of infection to prevent systemic spread.
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Affiliation(s)
| | - Xiao Zhang
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
| | - Andrea Ascura
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
| | - Karen L Edelblum
- Department of Pathology, Immunology, and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey, USA
| | - Edward M Bonder
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
| | - Nan Gao
- Department of Biological Sciences, Rutgers University, Newark, New Jersey, USA
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Zhou J, Ma H, Zhang L. Mechanisms of Virulence Reprogramming in Bacterial Pathogens. Annu Rev Microbiol 2023; 77:561-581. [PMID: 37406345 DOI: 10.1146/annurev-micro-032521-025954] [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] [Indexed: 07/07/2023]
Abstract
Bacteria are single-celled organisms that carry a comparatively small set of genetic information, typically consisting of a few thousand genes that can be selectively activated or repressed in an energy-efficient manner and transcribed to encode various biological functions in accordance with environmental changes. Research over the last few decades has uncovered various ingenious molecular mechanisms that allow bacterial pathogens to sense and respond to different environmental cues or signals to activate or suppress the expression of specific genes in order to suppress host defenses and establish infections. In the setting of infection, pathogenic bacteria have evolved various intelligent mechanisms to reprogram their virulence to adapt to environmental changes and maintain a dominant advantage over host and microbial competitors in new niches. This review summarizes the bacterial virulence programming mechanisms that enable pathogens to switch from acute to chronic infection, from local to systemic infection, and from infection to colonization. It also discusses the implications of these findings for the development of new strategies to combat bacterial infections.
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Affiliation(s)
- Jianuan Zhou
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China;
| | - Hongmei Ma
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China;
| | - Lianhui Zhang
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Center, South China Agricultural University, Guangzhou, China;
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Stuckey PV, Santiago-Tirado FH. Fungal mechanisms of intracellular survival: what can we learn from bacterial pathogens? Infect Immun 2023; 91:e0043422. [PMID: 37506189 PMCID: PMC10501222 DOI: 10.1128/iai.00434-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
Fungal infections represent a major, albeit neglected, public health threat with serious medical and economic burdens globally. With unacceptably high mortality rates, invasive fungal pathogens are responsible for millions of deaths each year, with a steadily increasing incidence primarily in immunocompromised individuals. The poor therapeutic options and rise of antifungal drug resistance pose further challenges in controlling these infections. These fungal pathogens have adapted to survive within mammalian hosts and can establish intracellular niches to promote survival within host immune cells. To do that, they have developed diverse methods to circumvent the innate immune system attack. This includes strategies such as altering their morphology, counteracting macrophage antimicrobial action, and metabolic adaptation. This is reminiscent of how bacterial pathogens have adapted to survive within host cells and cause disease. However, relative to the great deal of information available concerning intracellular bacterial pathogenesis, less is known about the mechanisms fungal pathogens employ. Therefore, here we review our current knowledge and recent advances in our understanding of how fungi can evade and persist within host immune cells. This review will focus on the major fungal pathogens, including Cryptococcus neoformans, Candida albicans, and Aspergillus fumigatus, among others. As we discover and understand the strategies used by these fungi, similarities with their bacterial counterparts are becoming apparent, hence we can use the abundant information from bacteria to guide our studies in fungi. By understanding these strategies, new lines of research will open that can improve the treatments of these devastating fungal diseases.
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Affiliation(s)
- Peter V. Stuckey
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Felipe H. Santiago-Tirado
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
- Warren Center for Drug Discovery, University of Notre Dame, Notre Dame, Indiana, USA
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Ribeiro JM, Canales J, Costas MJ, Cabezas A, Pinto RM, García-Díaz M, Martín-Cordero P, Cameselle JC. Genomic Distribution of Pro-Virulent cpdB-like Genes in Eubacteria and Comparison of the Enzyme Specificity of CpdB-like Proteins from Salmonella enterica, Escherichia coli and Streptococcus suis. Int J Mol Sci 2023; 24:ijms24044150. [PMID: 36835561 PMCID: PMC9958556 DOI: 10.3390/ijms24044150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/15/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023] Open
Abstract
The cpdB gene is pro-virulent in avian pathogenic Escherichia coli and in Salmonella enterica, where it encodes a periplasmic protein named CpdB. It is structurally related to cell wall-anchored proteins, CdnP and SntA, encoded by the also pro-virulent cdnP and sntA genes of Streptococcus agalactiae and Streptococcus suis, respectively. CdnP and SntA effects are due to extrabacterial hydrolysis of cyclic-di-AMP, and to complement action interference. The mechanism of CpdB pro-virulence is unknown, although the protein from non-pathogenic E. coli hydrolyzes cyclic dinucleotides. Considering that the pro-virulence of streptococcal CpdB-like proteins is mediated by c-di-AMP hydrolysis, S. enterica CpdB activity was tested as a phosphohydrolase of 3'-nucleotides, 2',3'-cyclic mononucleotides, linear and cyclic dinucleotides, and cyclic tetra- and hexanucleotides. The results help to understand cpdB pro-virulence in S. enterica and are compared with E. coli CpdB and S. suis SntA, including the activity of the latter on cyclic-tetra- and hexanucleotides reported here for the first time. On the other hand, since CpdB-like proteins are relevant to host-pathogen interactions, the presence of cpdB-like genes was probed in eubacterial taxa by TblastN analysis. The non-homogeneous genomic distribution revealed taxa with cpdB-like genes present or absent, identifying eubacteria and plasmids where they can be relevant.
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Affiliation(s)
- João Meireles Ribeiro
- Grupo de Enzimología, Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Medicina y Ciencias de la Salud, Universidad de Extremadura, 06006 Badajoz, Spain
| | - José Canales
- Grupo de Enzimología, Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Medicina y Ciencias de la Salud, Universidad de Extremadura, 06006 Badajoz, Spain
| | - María Jesús Costas
- Grupo de Enzimología, Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Medicina y Ciencias de la Salud, Universidad de Extremadura, 06006 Badajoz, Spain
| | - Alicia Cabezas
- Grupo de Enzimología, Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Medicina y Ciencias de la Salud, Universidad de Extremadura, 06006 Badajoz, Spain
| | - Rosa María Pinto
- Grupo de Enzimología, Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Medicina y Ciencias de la Salud, Universidad de Extremadura, 06006 Badajoz, Spain
| | - Miguel García-Díaz
- Unidad de Aparato Digestivo, Hospital de Zafra, Área de Salud Llerena-Zafra, Servicio Extremeño de Salud, 06300 Zafra, Spain
| | - Paloma Martín-Cordero
- Servicio de Microbiología, Hospital Universitario de Badajoz, Servicio Extremeño de Salud, 06006 Badajoz, Spain
| | - José Carlos Cameselle
- Grupo de Enzimología, Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Medicina y Ciencias de la Salud, Universidad de Extremadura, 06006 Badajoz, Spain
- Correspondence: ; Tel.: +34-924-289-470
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