In general, MAPK inhibition resulted in a greater reduction of cytokine production in PCM treated HKs compared to BCM treated HKs. Results represented as mean ± SD, n = 3, *p < 0.05, **p < 0.01. We have previously described characteristic morphology changes in BCM treated HKs [20]. The effects of MAPK inhibitors on BCM induced cell morphology were investigated here. Inhibition of JNK, p38, or ERK did not

prevent the biofilm-induced formation of filopodial structures in HKs (data not shown). Overall, this indicates that cytoskeletal rearrangements buy NVP-BGJ398 induced by BCM act through MAPK-independent mechanisms. Discussion S. aureus biofilm and planktonic-conditioned medium induced distinct responses in HKs in vitro. The adverse effects of planktonic bacterial cultures on mammalian cells have been well documented in vitro. Bacterial cells grown in broth

cultures have long been assumed to retain the same pathogenic properties as bacteria in natural settings. While important discoveries have been realized based on planktonic studies, data presented here provide evidence that bacterial biofilms differentially induce pathogenesis in cultured HKs. Host-pathogen interactions were investigated between a clinical isolate of S. aureus and HKs. A preliminary analysis of the extracellular proteome of S. LY2874455 aureus biofilm and planktonic cultures was performed by 1D gel electrophoresis and mass spectrometry. Several differences were observed in the 1D gel band patterns of BCM and PCM (Figure 1). The total protein concentrations of BCM and PCM were found to be similar, but BCM clearly contained more features. Smearing of BCM in 1D gels was observed indicating possible bacterial protease activity, although such a protease was not identified by mass spectrometry (Table 1). S. aureus secretes Aurora Kinase a variety of proteases which are important in pathogenesis [24]. The presence of such a protease could explain some of the observed effects in HKs after

treatment with BCM or PCM. Several 1D gel bands visible in PCM and not BCM contained glycolytic enzymes (Figure 1, Table 1). The presence of intracellular glycolytic enzymes in the extracellular proteome of S. aureus may be due to cell lysis, but cell wall Quisinostat in vivo associated glycolytic enzymes have been described for numerous pathogens, including S. aureus [25, 26]. Links between central metabolism and virulence in S. aureus have been described. In S. aureus, when carbon sources are plentiful, glycolysis is active while the tricarboxcylic acid (TCA) cycle is largely repressed [27]. The TCA cycle has been described as a signal transduction pathway capable of regulating toxin production [28], adhesion synthesis and biofilm formation [29, 30], and antibiotic susceptibility [31]. Additionally, S.