Neutrophil activation by Escherichia coli isolates from human intestine: effects of bacterial hydroperoxidase activity and surface hydrophobicity

• Main Authors: Mariam Moshkovskaya, Tatyana Vakhrusheva, Daria Rakitina, Julia Baykova, Oleg Panasenko, Lilia Basyreva, Sergey Gusev, Alexander Gusev, Elena Mikhalchik, Natalia Smolina, Gennadiy Dobretsov, Petr Scherbakov, Asfold Parfenov, Nina Fadeeva, Olga Pobeguts, Vadim Govorun
• Format: Article
• Language: English
• Published: Wiley 2020-03-01
• Series: FEBS Open Bio
• Subjects: chemiluminescence; Crohn’s disease; E. coli; fluorescent probes; neutrophil activation; peroxidase
• Online Access: https://doi.org/10.1002/2211-5463.12796

Successful colonization of the intestine requires that bacteria interact with the innate immune system and, in particular, neutrophils. Progression of inflammatory bowel diseases (IBD) is associated with alterations in gut microbiota, and dysbiosis in Crohn’s disease (CD) patients is often associated with an expansion of Escherichia coli. Here, we investigated the ability of such E. coli isolates to avoid neutrophil activation and to utilize reactive oxygen species. Neutrophil activation was detected in vitro in normal human blood via luminol chemiluminescence (CL) induced by reactive oxygen and halogen species generated by neutrophils. No significant difference in neutrophil activation in vitro was detected between isolates from inflamed (23 isolates) vs healthy intestines (5 isolates), with 10‐fold variation within both groups (2.9–61.2 mV). CL activity of isolates from the same patient differed by 1.5–5 times. Twenty‐four isolates from ileal aspirate, biopsy, and feces of seven patients with CD and one patient with no intestine inflammation were tested for extracellular peroxidase and catalase activity and cell surface hydrophobicity. Average values between patients varied from 26 ± 3 to 73 ± 18 µmol·g−1 of air dry weight for peroxidase activity, from 15 ± 2 to 189 ± 56 mmol·g−1 of air dry weight for catalase activity, and from 5 ± 3 to 105 ± 9 a.u. for the hydrophobic probe fluorescence. Extracellular peroxidase activity and hydrophobicity of bacterial cell surface correlated negatively with stimulated neutrophil CL. The ability of some isolates to avoid neutrophil activation and to utilize reactive oxygen species may provide a strategy to survive assault by the innate immune system.