Hydrogen peroxide (H₂O₂) induces actin and some heat‐shock proteins in Drosophila cells

Abstract

Drosophila cells of a clone derived from line Kc were treated with various concentrations of hydrogen peroxide (H202). The concentration of 10 mM was lethal, whereas concentrations of 1 -100 pM did not affect cell viability, rate of multiplication or protein synthesis. The intermediate concentration of 1 mM H z 0 2 was used to study the response of the cells to an oxidative stress.We observed a transitory decrease of the global protein synthesis, which was accompanied by changes in the polypeptide pattern. There was a 2.5-fold increase of the synthesis of the heat-shock proteins 70-68 and 23. The most prominent response was a 6.5-fold increase of actin synthesis 3 h after a 1 mM H 2 0 2 treatment. When aminotriazole (an inhibitor of catalase) was added in association with H202, the increase of actin synthesis became 8.5-fold. Experiments in which catalase was added at various times after H 2 0 2 showed that a 10-min treatment with H 2 0 2 was sufficient to induce actin and heat-shock protein synthesis 3 h later. HzOz was shown to induce the transcriptional activation of an actin gene and of the heat-shock protein genes 70 and 23 within minutes.These results are coherent with the hypothesis that the byproducts of O2 reduction (the superoxide ion and hydrogen peroxide) could be inducers of the heat-shock response. Whether the increase of actin synthesis is a stress-related response, and the mode of action of H 2 0 2 are discussed The heat-shock proteins (hsps), which are synthesised when all living organisms or in vitro cells are exposed to temperatures approximately 5 -20 "C above their optimal growth temperature, can also be induced by a wide range of various agents (for reviews see [l, 21). For example, in Drosophila Kc cells, hsps were shown to be induced without elevation of temperature, by ethanol, arsenite [3], recovery from anoxia [4] and cadmium [5]. The mechanism of induction of hsps is not entirely understood. A heat-shock transcription factor, which binds a consensus sequence in all the heatshock genes has recently been isolated and characterised (for a review see [6]). The heat-shock transcription factor is activated in heat-shocked cells, but what triggers this activation is not known. An interesting question, considering the different agents capable of inducing the synthesis of hsps, is to what extent they might act through a common pathway.We showed previously that in Kc Drosophifa cells the hsps were induced when the cells were reoxygenated after a period of anoxia. At the same time the rate of oxygen consumption was twice the normal rate [4]. This rapid increase of O2 uptake could lead to an overproduction of the products of O2 reduction such as the superoxide ion (0;) and hydrogen peroxide (H20z) [7]. These highly reactive and toxic O2 species were shown to be implicated in many disease states and particularly in tumor promotion [7 -101. We suggested that they might play a role in the chain of events leading to hsp synthesis [4]. In order to test this hypothesis we studied the effect of hydrogen...

Chemical Signals of Vector Beetle Facilitate the Prevalence of a Native Fungus and the Invasive Pinewood Nematode

“…Effect of metal stress on the expression of CeHSP17 in C. elegans: Given the fact that sHSP synthesis can be highly induced by many environmental stimuli such as such as extreme temperature, oxidative stress, heavy metals, and toxins (Courgeon et al, 1988;Kitagawa et al, 2000;Li et al, 2010;Ezemaduka et al, 2014), it is of no doubt that CeHSP17 may also be induced by metal stress. We therefore investigated the expression of CeHSP17 in worms treated with heavy metal ions.…”

Hydrogen peroxide activates immediate binding of a Drosophila factor to DNA heat‐shock regulatory element in vivo and in vitro

“…Similarly, increasing concentrations of H 2 0 2 were found to affect the level of heat-shock-element-binding activity. In cell cultures, the optimal H 2 0 2 concentration was 1 mM, since higher concentrations cause bleb formation, disruption of membrane and decrease in global protein synthesis [23]. Fig.…”

Expression of fetal isoforms of actin after transplantation injury

“…Free radicals causing injury in transplanted organs can also induce actin and other intermediate early genes in vitro [5]. Although we presume that this injury induced the expression of the p/y actins in the murine heart grafts, it is possible that other inducers of these important myocardial proteins also participated in their induction.…”

“…cells. A particularly relevant example of the latter is genes that encode various isoforms of actin that are induced in vitro by free radical injury [5]. Of the three isoforms of actin, the p and y isoforms which are found in the developmental stages of cardiogenesis [S, 18, 19, 271 appear to be more commonly induced by reperfusion than the a isoform, which is the predominant isoform in the adult heart.…”