Chelation of Membrane-Bound Cations by Extracellular DNA Activates the Type VI Secretion System in Pseudomonas aeruginosa.
Pseudomonas aeruginosa employs its type VI secretion system (T6SS) as a highly effective and tightly regulated weapon to deliver toxic molecules to target cells. T6SS-secreted proteins of P. aeruginosa can be detected in the sputum of cystic fibrosis (CF) patients, who typically present a chronic and polymicrobial lung infection. However, the mechanism of T6SS activation in the CF lung is not fully understood. Here we demonstrate that extracellular DNA (eDNA), abundant within the CF airways, stimulates the dynamics of the H1-T6SS cluster apparatus in Pseudomonas aeruginosa PAO1. Addition of Mg(2+) or DNase with eDNA abolished such activation, while treatment with EDTA mimicked the eDNA effect, suggesting that the eDNA-mediated effect is due to chelation of outer membrane-bound cations. DNA-activated H1-T6SS enables P. aeruginosa to nonselectively attack neighboring species regardless of whether or not it was provoked. Because of the importance of the T6SS in interspecies interactions and the prevalence of eDNA in the environments that P. aeruginosa inhabits, our report reveals an important adaptation strategy that likely contributes to the competitive fitness of P. aeruginosa in polymicrobial communities.
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.|Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada.
Mike
M
Wilton
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.|Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Megan J Q
MJQ
Wong
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.|Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Le
L
Tang
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.|Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Xiaoye
X
Liang
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.|Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
Richard
R
Moore
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.|Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada.
Michael D
MD
Parkins
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.|Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada.|Faculty of Science and Technology, Athabasca University, Athabasca, AB, Canada.
Shawn
S
Lewenza
Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada tdong@ucalgary.ca.|Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada.|Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.|Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
Tao G
TG
Dong
D002412:Cations / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D003550:Cystic Fibrosis / Q000150:complications; D004247:DNA / Q000378:metabolism*; D005110:Extracellular Space; D006801:Humans; D011552:Pseudomonas Infections / Q000209:etiology; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D000069376:Type VI Secretion Systems
D002412:Cations; D000069376:Type VI Secretion Systems; D004247:DNA