Responses of the 27-kDa heat shock protein to UVB irradiation in human epidermal melanocytes

• Published in: Experimental dermatology Vol. 17; no. 2; pp. 108 - 114
• Main Authors: Shi, Biao, Grahn, Jennifer C., Reilly, Debra A., Dizon, Theresa C., Isseroff, R. Rivkah
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2008; Blackwell
• Subjects: Biological and medical sciences; Cells, Cultured; Dermatology; Epidermis - cytology; Epidermis - metabolism; Epidermis - radiation effects; Gene Expression Regulation - radiation effects; Heat-Shock Proteins - genetics; Heat-Shock Proteins - metabolism; HSP27; HSP27 Heat-Shock Proteins; Humans; Medical sciences; melanocytes; Melanocytes - cytology; Melanocytes - metabolism; Melanocytes - radiation effects; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; p38 Mitogen-Activated Protein Kinases - metabolism; Phosphorylation - radiation effects; Protein Isoforms - genetics; Protein Isoforms - metabolism; Protein Transport - radiation effects; Reactive Oxygen Species - metabolism; Signal Transduction - physiology; ultraviolet B; Ultraviolet Rays; Human; Heat choc protein 27; melanocytes; Dermatology; UVB radiation; ultraviolet B; Melanocyte; Heat shock protein; HSP27; Epidermis
• ISSN: 0906-6705; 1600-0625
• DOI: 10.1111/j.1600-0625.2007.00641.x

:  Solar ultraviolet radiation (UVR) is a major environmental hazard for the skin, and UVB (280–320 nm) has been proposed to be a main factor for melanoma development. In response to sunlight exposure, the skin has adapted a number of innate resistance mechanisms. Among them is the small heat shock protein of 27 kDa (HSP27) known to play a role in the protection of cells from variety of environmental insults including UV irradiation. In this study, we demonstrated that UVB irradiation of cultured normal epidermal melanocytes initiates changes in HSP27 phosphorylation and localization. In unstressed melanocytes, HSP27 was present as the non‐phosphorylated isoform. UVB irradiation with a physiological dose (7–25 mJ/cm2) resulted in the formation of a mono‐phosphorylated isoform and sometimes a bi‐phosphorylated isoform. The UVB‐induced HSP27 phosphorylation was inhibited when melanocytes were treated with the antioxidant N‐acetyl cysteine or inhibitor of p38 MAP kinase prior to UVB exposure, suggesting that UVB induced HSP27 phosphorylation through reactive oxygen species/p38 MAP kinase pathway. In response to UBV irradiation, HSP27 in melanocytes translocated from the cytoplasm to the nucleus. The HSP27 responses may provide some protective role against UVB‐induced cell damage in the skin.