Pseudomonas aeruginosa lipopolysaccharide inhibits Candida albicans hyphae formation and alters gene expression during biofilm development. (12th October 2012)

• Record Type: Journal Article
• Authors: Bandara, H.M.H.N.; K Cheung, B.P.; Watt, R.M.; Jin, L.J.; Samaranayake, L.P.
• Is Part Of: Molecular oral microbiology. Volume 28:Number 1(2013:Feb.)
• Page Start: 54
• Page End: 69
• Publication Date: 2012-10-12
• Subjects: Mouth -- Microbiology -- Periodicals; Respiratory infections -- Microbiology -- Periodicals; Mouth -- Diseases -- Immunological aspects -- Periodicals; 617.522
• DOI: 10.1111/omi.12006
• Languages: English
• ISSNs: 2041-1006

Abstract

<abstract abstract-type="main" id="omi12006-abs-0001"> <title>Summary</title> <p>Elucidation of bacterial and fungal interactions in multispecies biofilms will have major impacts on understanding the pathophysiology of infections. The objectives of this study were to (i) evaluate the effect of <italic>Pseudomonas aeruginosa</italic> lipopolysaccharide (LPS) on <italic>Candida albicans</italic> hyphal development and transcriptional regulation, (ii) investigate protein expression during biofilm formation, and (iii) propose likely molecular mechanisms for these interactions. The effect of LPS on <italic>C. albicans</italic> biofilms was assessed by XTT‐reduction and growth curve assays, light microscopy, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Changes in candidal hypha‐specific genes (HSGs) and transcription factor <italic>EFG1</italic> expression were assessed by real‐time polymerase chain reaction and two‐dimensional gel electrophoresis, respectively. Proteome changes were examined by mass spectrometry. Both metabolic activities and growth rates of LPS‐treated <italic>C. albicans</italic> biofilms were significantly lower (<italic>P </italic>< 0.05). There were higher proportions of budding yeasts in test biofilms compared with the controls. SEM and CLSM further confirmed these data. Significantly upregulated HSGs (at 48 h) and <italic>EFG1</italic> (up to 48 h) were noted in the test biofilms (<italic>P</italic> < 0.05) but cAMP levels remained unaffected. Proteomic analysis showed suppression of candidal septicolysin‐like protein, potential reductase‐flavodoxin fragment, serine hydroxymethyltransferase, hypothetical proteins Cao19.10301(<italic>ATP7</italic>), CaO19.4716(GDH1), CaO19.11135(<italic>PGK1</italic>), CaO19.9877(<italic>HNT1</italic>) by <italic>P. aeruginosa </italic>LPS. Our data imply that bacterial LPS inhibit <italic>C. albicans</italic> biofilm formation and hyphal development. The <italic>P. aeruginosa </italic>LPS likely target glycolysis‐associated mechanisms during candidal filamentation.</p> </abstract>