title: Short Palate, Lung, and Nasal Epithelial Clone 1 Has Antimicrobial and Antibiofilm Activities against the Burkholderia cepacia Complex.
abstract: The opportunistic bacteria of the Burkholderia cepacia complex (Bcc) are extremely pathogenic to cystic fibrosis (CF) patients, and acquisition of Bcc bacteria is associated with a significant increase in mortality. Treatment of Bcc infections is difficult because the bacteria are multidrug resistant and able to survive in biofilms. Short palate, lung, and nasal epithelial clone 1 (SPLUNC1) is an innate defense protein that is secreted by the upper airways and pharynx. While SPLUNC1 is known to have antimicrobial functions, its effects on Bcc strains are unclear. We therefore tested the hypothesis that SPLUNC1 is able to impair Bcc growth and biofilm formation. We found that SPLUNC1 exerted bacteriostatic effects against several Bcc clinical isolates, including B. cenocepacia strain J2315 (50% inhibitory concentration [IC50] = 0.28 μM), and reduced biofilm formation and attachment (IC50 = 0.11 μM). We then determined which domains of SPLUNC1 are responsible for its antimicrobial activity. Deletions of SPLUNC1's N terminus and α6 helix did not affect its function. However, deletion of the α4 helix attenuated antimicrobial activity, while the corresponding α4 peptide displayed antimicrobial activity. Chronic neutrophilia is a hallmark of CF lung disease, and neutrophil elastase (NE) cleaves SPLUNC1. However, we found that the ability of SPLUNC1 to disrupt biofilm formation was significantly potentiated by NE pretreatment. While the impact of CF on SPLUNC1-Bcc interactions is not currently known, our data suggest that understanding this interaction may have important implications for CF lung disease.
authors.affiliation: Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Saira
authors.initials: S
authors.lastname: Ahmad
authors.affiliation: Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Jean
authors.initials: J
authors.lastname: Tyrrell
authors.affiliation: Department of Chemistry, The University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: William G
authors.initials: WG
authors.lastname: Walton
authors.affiliation: Macromolecular Interactions Facility, The University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Ashutosh
authors.initials: A
authors.lastname: Tripathy
authors.affiliation: Department of Chemistry, The University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Redinbo
authors.affiliation: Cystic Fibrosis Center/Marsico Lung Institute, The University of North Carolina, Chapel Hill, North Carolina, USA Department of Cell Biology and Physiology, The University of North Carolina, Chapel Hill, North Carolina, USA tarran@med.unc.edu.
authors.forename: Robert
authors.initials: R
authors.lastname: Tarran
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D001665:Binding Sites; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D042602:Burkholderia cepacia complex / Q000187:drug effects* / Q000254:growth & development; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D019272:Leukocyte Elastase / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D054730:Protein Interaction Domains and Motifs; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; C485599:BPIFA1 protein, human; D006023:Glycoproteins; D010750:Phosphoproteins; D011994:Recombinant Proteins; D019272:Leukocyte Elastase