Effect of <i>Pseudomonas aeruginosa</i> Alginate on <i>Escherichia col</i><i>i</i>- and <i>Staphylococcus aureu</i><i>s</i>-lnduced Inflammatory Mediator Release from Human Cells

Abstract

We analyzed the role of soluble purified Pseudomonas aeruginosa alginate on Escherichia coli K-12 (pANN5211) as well as on Staphylococcus aureus 121c-induced inflammatory mediator release from human platelets, granulocytes, and basophils. In the presence of alginate (1–4 mg/ml), the mucoid exopolysaccharide of P. aeruginosa, the bacteria-induced inflammatory mediator release was modulated as follows: (1) the E. coli- as well as S. aureus-induced chemiluminescence response from human neutrophils increased 2- to 3-fold and 5- to 6-fold, respectively; (2) the E. coli-induced leukotriene B₄ formation from human neutrophils was enhanced (from 29.17 ± 1.8 up to 36.9 ± 4 ng/10⁷ cells) as was also observed for the E. coli- and S. aureus-induced histamine release (3- to 4-fold) and the 12-hydroxyeicosatetraenoic acid generation from human platelets (2-fold), and (3) prolonged duration of the E.coli-induced increase in CD11b expression was observed. Alginate by itself was inactive. Our results provide evidence that alginate interacts with hemolysin-producing E. coli and S. aureus bacteria and thus leads to a modulation of the cellular response pattern, which leads to the local destruction of the lung in cystic fibrosis.

Effect of <i>Pseudomonas aeruginosa</i> on lnterleukin-8 Release from Human Phagocytes

“…We have previously shown that in contrast to nonmucoid P. aeruginosa mucoid P. aeruginosa strains as well as puri fied alginate inhibit the generation of the chemotactic LTB4 [19,20,25]. In the present study we show that ( 1 ) P. aerugi nosa bacteria, mucoid and nonmucoid, are able to induce the generation of the chemotactic IL-8 from human phago cytes, and P aeruginosa alginate does not inhibit IL-8 re lease from human phagocytes.…”

“…Mucoid in contrast to nonmucoid P. aeruginosa strains failed to induce the chemotactically active LTB4 [20,25]. Thus, we compared the capacity of CF3 and CF3M strains to induce IL-8 from PMN and PBMC.…”

“…Cell viability was studied by trypan blue exclusion (PMN; PBMC) and by analysis of lactate dehydrogenase (PMN) (LDH; EC 1.1.1.27) release front stimulated and nonstimulated cells [25].…”

“…Recently, we have shown that alginate is responsible for the deactivating properties of mucoid P. aeruginosa strains [25] on neutrophil functions, e.g. LTB4 generation from hu man PMN.…”

Induction of Inflammatory Mediator Release (12-Hydroxyeicosatetraenoic Acid) from Human Platelets by <i>Pseudomonas aeruginosa</i>

“…exotoxin A, exoenzyme S. cytotoxin, the mucoid exopolysaccharide (alginate), the heat-labile (phospholipase C) as well as the heat-stable hemolysin (glycolipid) and at least two different proteases [4][5][6][7], Recently, we have shown that the interaction be tween pathogenicity factors, e.g. the P aeruginosa algi nate and the hemolysins of Escherichia coli, Staphylococ cus aureus and Serratia marcescens, may contribute to the pathophysiological understanding of P. aeruginosa infec tion in CF [8]. Nonetheless, in CF there is as yet no satis factory explanation for the deleterious outcome of the chronic Pseudomonas infection which is characterized by a massive lung infiltration with neutrophils as well as local destruction of lung tissue [3,9],…”