Induction of stress proteins by tobacco smoke in human monocytes: modulation by antioxidants.

Tobacco smoke (TS) induced in human monocytes the synthesis of both the classical heat shock proteins (HSP) (Hsp70, Hsp90, Hsp110) and the oxidation-specific stress protein (SP) heme oxygenase (HO). To determine the role of reactive oxygen species in SP induction by TS, we incubated the monocytes with various antioxidants before exposure to TS. Quercetin and N-acetylcysteine (NAC) both prevented the induction of HO by TS but not, or less so, than that of the classical HSP, while the nitric oxide synthase inhibitor L-nitroarginine had no effect. Thus, at least two mechanisms appear involved in SP induction by TS; (i) the induction of HO (oxidation-dependent), which was prevented by quercetin and NAC; and (ii) the induction of Hsp70, which was, at least in part, oxidation-independent. SP induction might represent an adequate biosensor for TS and other radical-mediated environmental exposures.