title: The Burkholderia cenocepacia peptidoglycan-associated lipoprotein is involved in epithelial cell attachment and elicitation of inflammation.
abstract: The Burkholderia cepacia complex (Bcc) is a group of Gram-negative opportunistic pathogens causing infections in people with cystic fibrosis (CF). Bcc is highly antibiotic resistant, making conventional antibiotic treatment problematic. The identification of novel targets for anti-virulence therapies should improve therapeutic options for infected CF patients. We previously identified that the peptidoglycan-associated lipoprotein (Pal) was immunogenic in Bcc infected CF patients; however, its role in Bcc pathogenesis is unknown. The virulence of a pal deletion mutant (Δpal) in Galleria mellonella was 88-fold reduced (p < .001) compared to wild type. The lipopolysaccharide profiles of wild type and Δpal were identical, indicating no involvement of Pal in O-antigen transport. However, Δpal was more susceptible to polymyxin B. Structural elucidation by X-ray crystallography and calorimetry demonstrated that Pal binds peptidoglycan fragments. Δpal showed a 1.5-fold reduced stimulation of IL-8 in CF epithelial cells relative to wild type (p < .001), demonstrating that Pal is a significant driver of inflammation. The Δpal mutant had reduced binding to CFBE41o-cells, but adhesion of Pal-expressing recombinant E. coli to CFBE41o-cells was enhanced compared to wild-type E. coli (p < .0001), confirming that Pal plays a direct role in host cell attachment. Overall, Bcc Pal mediates host cell attachment and stimulation of cytokine secretion, contributing to Bcc pathogenesis.
authors.affiliation: Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, Ireland.
authors.forename: Ruth
authors.initials: R
authors.lastname: Dennehy
authors.affiliation: National Research Council, Institute of Biostructures and Bioimaging, Naples, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Romano
authors.affiliation: National Research Council, Institute of Biostructures and Bioimaging, Naples, Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Ruggiero
authors.affiliation: Centre for Experimental Medicine, Queen's University, Belfast, Northern Ireland.|Faculty of Pharmacy, Department of Microbiology, Alexandria University, Alexandria, Egypt.
authors.forename: Yasmine F
authors.initials: YF
authors.lastname: Mohamed
authors.affiliation: Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, Ireland.
authors.forename: Simon L
authors.initials: SL
authors.lastname: Dignam
authors.affiliation: Centre for Experimental Medicine, Queen's University, Belfast, Northern Ireland.
authors.forename: Cristóbal
authors.initials: C
authors.lastname: Mujica Troncoso
authors.affiliation: Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, Ireland.
authors.forename: Máire
authors.initials: M
authors.lastname: Callaghan
authors.affiliation: Centre for Experimental Medicine, Queen's University, Belfast, Northern Ireland.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Valvano
authors.affiliation: National Research Council, Institute of Biostructures and Bioimaging, Naples, Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Berisio
authors.affiliation: Centre of Microbial Host Interactions, Institute of Technology Tallaght, Dublin, Ireland.
authors.forename: Siobhán
authors.initials: S
authors.lastname: McClean
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000737:chemistry* / Q000502:physiology; D001665:Binding Sites; D019121:Burkholderia Infections / Q000276:immunology* / Q000382:microbiology; D057508:Burkholderia cenocepacia / Q000276:immunology* / Q000472:pathogenicity; D002448:Cell Adhesion; D002478:Cells, Cultured; D018360:Crystallography, X-Ray; D003550:Cystic Fibrosis / Q000382:microbiology; D016207:Cytokines / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D004847:Epithelial Cells / Q000382:microbiology / Q000502:physiology*; D004926:Escherichia coli; D006801:Humans; D007814:Larva / Q000382:microbiology; D008070:Lipopolysaccharides / Q000502:physiology; D008074:Lipoproteins / Q000737:chemistry* / Q000502:physiology; D008958:Models, Molecular; D009036:Moths; D010457:Peptidoglycan / Q000737:chemistry; D011113:Polymyxins / Q000494:pharmacology; D011485:Protein Binding; D000072417:Protein Domains
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines; D008070:Lipopolysaccharides; D008074:Lipoproteins; D010457:Peptidoglycan; D011113:Polymyxins
keywords: cystic fibrosis; host cell attachment; inflammation; pathogen-associated molecular patterns; peptidoglycan-associated lipoprotein