Propionic acid stimulates superoxide generation in human neutrophils

Sumi Nakao, Yoshiko Moriya, Shunsuke Furuyama, Richard Niederman, Hiroshi Sugiya

Research output: Contribution to journalArticlepeer-review


Short-chain carboxylic acids are the metabolic by-products of pathogenic anaerobic bacteria and are found at sites of infection in millimolar quantities. We previously reported that propionic acid, one of the short-chain carboxylic acids, induces an increase in intracellular Ca2+ ([Ca2+](i)) in human neutrophils. Here we investigate the effect of propionic acid on superoxide generation in human neutrophils. Propionic acid (10 mM) induced inositol 1,4,5-trisphosphate (IP3) formation and a rapidly transient increase in [Ca2+](i), but not superoxide generation, whereas 1 μM formylmethionyl-leucyl-phenylalanine (fMLP), a widely used neutrophil-stimulating bacterial peptide, stimulated not only IP3 formation and Ca2+ mobilization but also superoxide generation. The IP3 level induced by propionic acid was slightly lower than that induced by fMLP. The transient increase in [Ca2+](i) induced by propionic acid immediately returned to the basal level, whereas a sustained increase in [Ca2+](i), which was higher than the basal level, following a transient increase in [Ca2+](i) was induced by fMLP. The peak level induced by propionic acid was lower than that with fMLP. In the absence of extracellular Ca2+ thapsigargin, a potent inhibitor of endoplasmic reticulum Ca2+-ATPase, induced an increase in [Ca2+](i) even after propionic acid stimulation, but not after fMLP. The Ca2+ ionophore A23187 and thapsigargin induced superoxide generation by themselves. Propionic acid enhanced the superoxide generating effect of A23187 and thapsigargin. These results suggest that Ca2+ mobilization induced by propionic acid is much weaker than that with fMLP, and propionic acid is able to generate superoxide in the presence of a Ca2+ ionophore and a Ca2+ influx activator.

Original languageEnglish (US)
Pages (from-to)331-337
Number of pages7
JournalCell Biology International
Issue number5
StatePublished - May 1998


  • Calcium influx
  • Neutrophils (human)
  • Propionic acid
  • Superoxide

ASJC Scopus subject areas

  • Cell Biology


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