Swimming Motility Mediates the Formation of Neutrophil Extracellular Traps Induced by Flagellated Pseudomonas aeruginosa
| Autor: | Payel Sil, Dae-goon Yoo, Matthew Winn, Balázs Rada, Madison Floyd, Benoit Chassaing, Joanna B. Goldberg, Linda L. McCarter, Andrew T. Gewirtz, Christian Cullen |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Neutrophils Fluorescent Antibody Technique Pathology and Laboratory Medicine medicine.disease_cause Extracellular Traps Polymerase Chain Reaction Biochemistry Mice White Blood Cells 0302 clinical medicine Cell Movement Animal Cells Superoxides Microbial Physiology Medicine and Health Sciences Bacterial Physiology Enzyme-Linked Immunoassays Biology (General) Pseudomonas Aeruginosa Oxides Flow Cytometry Bacterial Pathogens Cell biology Cell Motility Chemistry Flagella Medical Microbiology Physical Sciences Pathogens Cellular Structures and Organelles Cellular Types Research Article Pathogen Motility Virulence Factors QH301-705.5 Immune Cells Phagocytosis Immunoblotting Immunology Motility Enzyme-Linked Immunosorbent Assay Flagellum Biology Research and Analysis Methods Microbiology 03 medical and health sciences Pseudomonas Virology Genetics medicine Animals Humans Pseudomonas Infections Immunoassays Microbial Pathogens Molecular Biology Blood Cells Innate immune system Bacteria Pseudomonas aeruginosa Organisms Chemical Compounds Biology and Life Sciences Proteins Bacteriology Cell Biology Flagellar Motility Neutrophil extracellular traps RC581-607 Mice Inbred C57BL 030104 developmental biology TLR5 Immunologic Techniques biology.protein Parasitology Immunologic diseases. Allergy Flagellin 030215 immunology |
| Zdroj: | PLoS Pathogens, Vol 12, Iss 11, p e1005987 (2016) PLoS Pathogens |
| ISSN: | 1553-7374 1553-7366 |
| Popis: | Pseudomonas aeruginosa is an opportunistic pathogen causing severe infections often characterized by robust neutrophilic infiltration. Neutrophils provide the first line of defense against P. aeruginosa. Aside from their defense conferred by phagocytic activity, neutrophils also release neutrophil extracellular traps (NETs) to immobilize bacteria. Although NET formation is an important antimicrobial process, the details of its mechanism are largely unknown. The identity of the main components of P. aeruginosa responsible for triggering NET formation is unclear. In this study, our focus was to identify the main bacterial factors mediating NET formation and to gain insight into the underlying mechanism. We found that P. aeruginosa in its exponential growth phase promoted strong NET formation in human neutrophils while its NET-inducing ability dramatically decreased at later stages of bacterial growth. We identified the flagellum as the primary component of P. aeruginosa responsible for inducing NET extrusion as flagellum-deficient bacteria remained seriously impaired in triggering NET formation. Purified P. aeruginosa flagellin, the monomeric component of the flagellum, does not stimulate NET formation in human neutrophils. P. aeruginosa-induced NET formation is independent of the flagellum-sensing receptors TLR5 and NLRC4 in both human and mouse neutrophils. Interestingly, we found that flagellar motility, not flagellum binding to neutrophils per se, mediates NET release induced by flagellated bacteria. Immotile, flagellar motor-deficient bacterial strains producing paralyzed flagella did not induce NET formation. Forced contact between immotile P. aeruginosa and neutrophils restored their NET-inducing ability. Both the motAB and motCD genetic loci encoding flagellar motor genes contribute to maximal NET release; however the motCD genes play a more important role. Phagocytosis of P. aeruginosa and superoxide production by neutrophils were also largely dependent upon a functional flagellum. Taken together, the flagellum is herein presented for the first time as the main organelle of planktonic bacteria responsible for mediating NET release. Furthermore, flagellar motility, rather than binding of the flagellum to flagellum-sensing receptors on host cells, is required for P. aeruginosa to induce NET release. Author Summary Pseudomonas aeruginosa leaves a large footprint in human disease because it causes infections in immunocompromised patients. Its ability to quickly adapt to diverse environments and to form biofilms poses a significant challenge to the medical community. Neutrophil granulocytes, professional phagocytes found cruising through the body’s circulatory system and tissues, provide the most efficient immune response against P. aeruginosa. Neutrophils utilize multiple strategies to eliminate bacteria. Formation of neutrophil extracellular traps (NETs), a DNA-based scaffold with attached antimicrobial proteins, provides an efficient mechanism to trap P. aeruginosa. The detailed mechanism of NET release induced by bacteria remains unclear. Our data show that the flagellum, the organelle that provides swimming motility to P. aeruginosa, is the main factor required to induce NET release. Our novel findings indicate that the flagellum, and in particular swimming motility, mediates P. aeruginosa-induced NET extrusion independently of the well-characterized flagellin receptors. The novel data presented here also suggest that down-regulation of flagellar motility characteristically seen in P. aeruginosa lung infections in cystic fibrosis is relevant for P. aeruginosa to avoid neutrophil attacks. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|