The Role of Norepinephrine in the Regulation of Growth, Adhesion and Invasion of Pseudomonas Aeruginosa in Human Lung Carcinoma Cell Culture

Mammalian hormones are shown to affect not only regulation of mammalian homeostasis but also play roles in cross-talk between microorganisms and their hosts. In our study, the roles of norepinephrine (NE) at two different concentrations on growth alterations, adhesion - invasion of Pseudomonas aeruginosa were investigated.

The effects of NE on the growth, adhesion - invasion of P. aeruginosa ATTC 27853 were examined in human lung carcinoma (A549) cell culture. We analysed two concentrations (HNE: 0.04μg/mL and LNE: 0.0017 μg/mL) of NE considering NE’s psychological levels in a healthy individual to imitate in vivo conditions of the host. Bacterial counts of growth and adhesion-invasion were examined by the colony counting method. Growth of bacterium was significantly reduced in the presence of NE at 90’ incubation (p: 0.0004 for high concentration and p: 0.0003 for low concentration); on the other hand, at 180’ minutes incubation, only low concentration reduced the growth (p˂0.0001). While adhesion was increased in the presence of low NE concentration (p: 0.013), there was no alteration in invasion of P. aeruginosa in the presence of NE (p˃0.05). Our results suggested that NE has different effects on the growth and adhesion of P. aeruginosa and these effects depend on concentration and incubation period.