The Bacteroides by-product succinic acid inhibits neutrophil respiratory burst by reducing intracellular pH.
AUTOR(ES)
Rotstein, O D
RESUMO
Short-chain fatty acids, particularly succinic acid, are major metabolic by-products of Bacteroides species. To determine their role as potential virulence factors in infections containing Bacteroides species, short-chain fatty acids were examined for their effect on the neutrophil respiratory burst. Succinate (30 to 50 mM) irreversibly impaired superoxide and hydrogen peroxide production in response to opsonized zymosan and phorbol myristate acetate when neutrophils were treated at pH 5.5 but not pH 6.0 or greater. Several other short-chain fatty acids tested produced similar inhibition. Reversible inhibition of oxygen consumption was found when neutrophils were incubated in succinate-containing medium (pH 6.0) as well as control medium (pH 6.0 and 5.5). Neutrophil cytoplasmic pH was measured by fluorimetric techniques to determine whether the inhibition was mediated via a reduction in intracellular pH. The intracellular pH of cells in control medium (pH 6.5 or less) was significantly reduced compared with pH 7.4. The addition of succinate (30 mM) to these media caused a further significant reduction in cytoplasmic pH at each pH level. The reduction in intracellular pH was sufficient to account for both the irreversible and reversible impairment of the neutrophil respiratory burst. Thus, short-chain fatty acids appear to exert their inhibition, at least in part, by reducing intracellular pH. These data also demonstrate the potential for interactions between Bacteroides species and their microenvironment to increase the virulence of an infection.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=260430Documentos Relacionados
- Succinic acid, a metabolic by-product of Bacteroides species, inhibits polymorphonuclear leukocyte function.
- A soluble Bacteroides by-product impairs phagocytic killing of Escherichia coli by neutrophils.
- The Synthesis of [gamma]-Aminobutyric Acid in Response to Treatments Reducing Cytosolic pH.
- Pirarucu By-Product Acid Silage Meal in Diets for Commercial Laying Hens
- Proton currents in human granulocytes: regulation by membrane potential and intracellular pH.