Heat shock protein 70 overexpression affects the response to ultraviolet light in murine fibroblasts. Evidence for increased cell viability and suppression of cytokine release.

Abstract

To elucidate cellular concepts for protection against ultraviolet (UV) light we investigated the effect of heat shock protein 70 (hsp70) overexpression on cell viability and on the secretion of UV-inducible immunological cytokines. Transfected murine fibrosarcoma cells (WEHI-S), overexpressing hsp70 or a sham transfected control were used. Overexpression of hsp70 was sufficient to markedly increase cell viability upon treatment with UVB (290-320 nm). Since long wave UV (UVA, 320-400 nm) as well as UVB turned out to stimulate the release of 02 radicals we studied the cell viability upon oxidative stress. Hsp70 overexpression increased viability upon treatment with hydrogen peroxide or menadione, but had no influence on UV-induced 02 release. UV-light is known to upregulate immunologic and proinflammatory cytokines such as IL-1 and IL-6. Oxidative stress appeared to exert a similar effect. Hsp7O overexpression markedly decreased the release of IL-6 induced by UVA, UVB and oxidative stress. To test whether the hsp70 mediated suppression is confined to events caused by UVlight we determined IL-i-mediated effects. IL-1-induced IL-6 release was reduced by hsp7O overexpression, whereas the IL-1 mediated activation of nuclear factor KB was not affected. Our data suggests that hsp70 plays a central role not only in cell protection against UV-light, but also in the regulation of proinflammatory cytokine release induced by UV-exposure. (J. Clin. Invest. 1995. 95:926-933.)

Transcriptional expression levels of cell stress marker genes in the Pacific oyster Crassostrea gigas exposed to acute thermal stress

“…This was also investigated in the oyster (Shamseldin et al 1997;Clegg et al 1998;Hamdoun et al 2003). This thermoresistant status (or acquired thermotolerance as described by Kregel 2002) not only protects the cells against heat (Mosser and Martin 1992;Mosser et al 1997;Gabai et al 1997) but also against many kinds of stress such as chemotherapeutic agents (Samali and Cotter 1996;Jaattela 1999), nitric oxide (Bellmann et al 1996), UV (Simon et al 1995) and irradiation (Park et al 2000;Kang et al 2002). The protective effects of HSP against free oxygen radicals are thought to explain their effectiveness against these different sources of cellular stress conditions.…”

IL-18 Reduces Ultraviolet Radiation-Induced DNA Damage and Thereby Affects Photoimmunosuppression

“…Therefore, dysregulation of UV-induced apoptosis will affect the photocarcinogenic risk. Several ways exist to inhibit UV-induced apoptosis, e.g., by overexpressing heat shock (29) or antiapoptotic proteins (30,31), by disrupting p53 function (32), or by blocking death receptor activation (33,34). Because these approaches allow the survival of cells carrying DNA damage, they may give rise to mutations and skin cancer.…”

Hsp72 chaperone function is dispensable for protection against stress-induced apoptosis

“…Heat shock protein 72 (Hsp72) protects mammalian cells from apoptosis induced by a variety of different stresses including heat, UVC radiation, ceramide, tumor necrosis factor alpha (TNFα), and some chemotoxic drugs (Ahn et al 1999;Buzzard et al 1998;Demidenko et al 2006;Dressel et al 2003;Gabai et al 1997;Jaattela et al 1992;Simon et al 1995;Sliutz et al 1996). As Hsp72 expression is induced in response to proteotoxic stresses such as heat, it may be important for preventing the excessive apoptosis of cells when organisms are exposed to extreme conditions.…”