Heat shock inhibits NADPH oxidase in human neutrophils

The heat shock response is a conserved, physiological, transient cellular response to injury. Several studies have suggested a link between the heat shock response and oxidative injury. We have investigated the effects of heat shock on superoxide anion generation by human neutrophils stimulated with opsonized zymosan or phorbol myristate acetate. Human neutrophils exposed to elevated temperatures or to the heavy metal cadmium synthetized a variety of heat shock proteins. In parallel to this protein synthesis, we observed a selective, reversible and temperature-dependent inhibition of NADPH oxidase activation, which was independent from variations of cytosolic pH or thiol group oxidation. Inhibition of NADPH oxidase by heat shock appeared related to the synthesis of heat shock proteins and may represent an intrinsic cellular mechanism to down regulate superoxide production.