Pyocyanin and 1-hydroxyphenazine produced by Pseudomonas aeruginosa inhibit the beating of human respiratory cilia in vitro.

Abstract

Pseudomonas aeruginosa culture filtrates varied in their ability to slow human ciliary beat frequency (7-71%). This activity did not correlate with known virulence factors. However, a close correlation (r = 0.97) existed between ciliary slowing and pigment content. In a prolonged culture, the increase in activity correlated (r = 0.94) with pigment accumulation. Gel filtration of lyophilized filtrate yielded a single peak of activity corresponding to the pigment fraction. Pyocyanin extracted from an active strain, and 1-hydroxyphenazine were purified by high performance liquid chromatography, and characterized by ultraviolet absorbance spectra and mass spectrometry. Both slowed cilia in a dose-dependent manner, and were synthesized and shown to be indistinguishable from the biological compounds. Pyocyanin caused gradual onset of slowing and ultimate widespread ciliostasis with epithelial disruption. 1-hydroxyphenazine caused rapid onset of ciliary slowing associated with dyskinesia and ciliostasis. Pyocyanin assayed within filtrates accounted for a significant proportion of the bioactivity present.

Induction of Neutrophil Apoptosis by thePseudomonas aeruginosaExotoxin Pyocyanin: A Potential Mechanism of Persistent Infection

“…Time course experiments were performed in the presence or absence of a concentration (50 M) of each compound previously shown to have biological effects in cell culture (21). After 3 h, an acceleration of apoptosis was observed in cells cultured with pyocyanin, which was statistically significant at 6 h in which 35.4 Ϯ 7.5% (mean Ϯ SE) of pyocyanin-treated cells were apoptotic compared with 7.1 Ϯ 2.4% of untreated cells ( p ϭ 0.001, n ϭ 4) (Fig.…”

Role of macrophage-stimulating protein and its receptor, RON tyrosine kinase, in ciliary motility.

“…The epithelial strips were viewed directly through a Nikon Diaphot-TMD phase-contrast microscope at a magnification of 400. An intact and fully ciliated epithelial strip with a smooth surface was selected, and serial readings of CBF were taken from the same point of the epithelial strip for 50 min using a photometric technique (36,37). After the determination of baseline CBF for 15 min, 50 l of Medium 199 alone (control) or Medium 199 containing MSP (final concentration; 1, 10, 50, or 100 ng/ml) was gently added to the well, and CBF was continuously measured.…”

A quorum sensing-associated virulence gene of Pseudomonas aeruginosa encodes a LysR-like transcription regulator with a unique self-regulatory mechanism

“…Genetic studies also identified the phzABC-DEFG operon as containing genes required for the synthesis of pyocyanin (13)(14)(15). Various in vitro studies using purified pyocyanin have shown that pyocyanin inhibits mammalian cell respiration, disrupts the beating of human cilia, inhibits the growth of epidermal cells, and inhibits the release of IL-2, which leads to the inhibition of T lymphocyte proliferation and Ig secretion by B-lymphocytes (16,17).…”