Differential Expression and Regulation of hsp70 and hsp90 by Phorbol Esters and Heat Shock

Abstract

Human peripheral blood monocytes (PBM) produce superoxide anions (O2-.) by a process involving electron transfer from NADPH to O2, catalyzed by the respiratory burst enzyme NADPH oxidase. We have previously shown that phagocytosis, while activating NADPH oxidase, induced in PBM the synthesis of heat shock (HS) proteins (HSP). The present study was undertaken to establish whether this increase in HSP expression was related to O2-. and/or to classical second messengers such as protein kinase C (PKC). Thus, the effects of the PKC activator phorbol 12-myristate 13-acetate (PMA) were compared with those of heat shock on the expression, in PBM, of the major HSP, hsp70 and hsp90, using biometabolic labeling, Western and Northern blotting, and gel mobility shift assays. PMA induced the accumulation of mRNA and an increased expression of hsp90 and, to a lesser extent, hsp/hsc70 (hsc is the cognate, constitutive form). This induction was also observed in PBM from patients with chronic granulomatous disease, a genetic defect in NADPH oxidase, and was abolished by the PKC inhibitors staurosporine and H-7. PMA did not cause activation of the HS factor, and the PMA-induced overexpression expression of HSP was not blocked by the transcriptional inhibitor actinomycin D. HSP-specific mRNA stability was increased after PMA exposure as compared with heat shock. These results suggest that O2-. is not involved in the PMA-mediated induction of hsp70 and hsp90 and that, in contrast to HS, PMA increases the expression of HSP as a result of PKC-induced mRNA stabilization rather than of transcriptional activation of HS genes.

Rac1 Regulates Stress-induced, Redox-dependent Heat Shock Factor Activation

“…This is in agreement with previous reports showing that the activation of HSF by exogenous oxidants is selective for the type of oxidant used, H 2 O 2 being effective while superoxide was not (35). The fact that superoxide dismutase does suppress HSF activation to a modest degree suggests that a secondary oxidant such as the hydroxyl radical, the formation of which requires both H 2 O 2 and superoxide, may also participate in HSF activation.…”

Effects of sauna bathing on stress-related genes expression in athletes and non-athletes

“…Stimulation of synthesis of heat-shock proteins and interleukins in leukocytes under stress factors, such as high temperature, was studied by Pizurki and Polla [23], Jacquier-Sarlin et al [24], and Polla and Cassarizza [25]. These authors have shown in in vitro studies of leukocytes that the increase in temperature to 41˚C causes a 10-fold increase in HSP concentration, which is significantly higher than that observed in the current study [23,24]. However, these experiments were performed in vitro, which makes a direct comparison with these results is impossible.…”

Regulation of cytochrome P4501A by protein kinase C: the role of heat shock protein70

“…Heat shock protein is a family of broad spectrum protein expressed in cells during stress and acts as molecular chaperon, which maintains normal conformity of other protein. Jacquier-Sarlin et al (Jacquier-Sarlin et al 1995) reported that HSP70, as well as HSP90 expression might be Fig. 3 a, b and c FACS of HSP70 from CF treated cultured hepatocytes.…”