title: Phosphatidylserine externalization and procoagulant activation of erythrocytes induced by Pseudomonas aeruginosa virulence factor pyocyanin.
abstract: The opportunistic pathogen Pseudomonas aeruginosa causes a wide range of infections in multiple hosts by releasing an arsenal of virulence factors such as pyocyanin. Despite numerous reports on the pleiotropic cellular targets of pyocyanin toxicity in vivo, its impact on erythrocytes remains elusive. Erythrocytes undergo an apoptosis-like cell death called eryptosis which is characterized by cell shrinkage and phosphatidylserine (PS) externalization; this process confers a procoagulant phenotype on erythrocytes as well as fosters their phagocytosis and subsequent clearance from the circulation. Herein, we demonstrate that P. aeruginosa pyocyanin-elicited PS exposure and cell shrinkage in erythrocyte while preserving the membrane integrity. Mechanistically, exposure of erythrocytes to pyocyanin showed increased cytosolic Ca(2+) activity as well as Ca(2+) -dependent proteolytic processing of μ-calpain. Pyocyanin further up-regulated erythrocyte ceramide abundance and triggered the production of reactive oxygen species. Pyocyanin-induced increased PS externalization in erythrocytes translated into enhanced prothrombin activation and fibrin generation in plasma. As judged by carboxyfluorescein succinimidyl-ester labelling, pyocyanin-treated erythrocytes were cleared faster from the murine circulation as compared to untreated erythrocytes. Furthermore, erythrocytes incubated in plasma from patients with P. aeruginosa sepsis showed increased PS exposure as compared to erythrocytes incubated in plasma from healthy donors. In conclusion, the present study discloses the eryptosis-inducing effect of the virulence factor pyocyanin, thereby shedding light on a potentially important mechanism in the systemic complications of P. aeruginosa infection.
authors.affiliation: Centre for Innovation, Canadian Blood Services, Hamilton, ON, Canada.|Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Syed M
authors.initials: SM
authors.lastname: Qadri
authors.affiliation: Centre for Innovation, Canadian Blood Services, Hamilton, ON, Canada.|Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: David A
authors.initials: DA
authors.lastname: Donkor
authors.affiliation: Centre for Innovation, Canadian Blood Services, Hamilton, ON, Canada.
authors.forename: Varsha
authors.initials: V
authors.lastname: Bhakta
authors.affiliation: Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Louise J
authors.initials: LJ
authors.lastname: Eltringham-Smith
authors.affiliation: Thrombosis and Atherosclerosis Research Institute (TaARI), McMaster University, Hamilton, ON, Canada.|Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Dhruva J
authors.initials: DJ
authors.lastname: Dwivedi
authors.affiliation: Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Jane C
authors.initials: JC
authors.lastname: Moore
authors.affiliation: Thrombosis and Atherosclerosis Research Institute (TaARI), McMaster University, Hamilton, ON, Canada.|Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Laura
authors.initials: L
authors.lastname: Pepler
authors.affiliation: Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.
authors.forename: Nikola
authors.initials: N
authors.lastname: Ivetic
authors.affiliation: Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Ishac
authors.initials: I
authors.lastname: Nazi
authors.affiliation: Thrombosis and Atherosclerosis Research Institute (TaARI), McMaster University, Hamilton, ON, Canada.|Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Alison E
authors.initials: AE
authors.lastname: Fox-Robichaud
authors.affiliation: Thrombosis and Atherosclerosis Research Institute (TaARI), McMaster University, Hamilton, ON, Canada.|Department of Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Liaw
authors.affiliation: Centre for Innovation, Canadian Blood Services, Hamilton, ON, Canada.|Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
authors.forename: William P
authors.identifier: http://orcid.org/0000-0002-5870-8189
authors.initials: WP
authors.lastname: Sheffield
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001777:Blood Coagulation / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000378:metabolism; D002413:Cations, Divalent; D002518:Ceramides / Q000378:metabolism; D000072817:Eryptosis / Q000187:drug effects; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005260:Female; D005337:Fibrin / Q000819:agonists / Q000096:biosynthesis; D006801:Humans; D017136:Ion Transport; D008297:Male; D008875:Middle Aged; D010718:Phosphatidylserines / Q000378:metabolism; D011516:Prothrombin / Q000819:agonists / Q000096:biosynthesis; D011552:Pseudomonas Infections / Q000097:blood* / Q000382:microbiology / Q000473:pathology; D011550:Pseudomonas aeruginosa / Q000472:pathogenicity* / Q000502:physiology; D011710:Pyocyanine / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000819:agonists / Q000378:metabolism; D018805:Sepsis / Q000097:blood* / Q000382:microbiology / Q000473:pathology; D037521:Virulence Factors / Q000494:pharmacology*
chemical_list: D002413:Cations, Divalent; D002518:Ceramides; D010718:Phosphatidylserines; D017382:Reactive Oxygen Species; D037521:Virulence Factors; D011516:Prothrombin; D005337:Fibrin; D011710:Pyocyanine; D002154:Calpain; C449002:mu-calpain; D002118:Calcium
keywords: Pseudomonas aeruginosa; coagulation; erythrocyte; phosphatidylserine; pyocyanin