The involvement of Smac/DIABLO, p53, NF-kB, and MAPK pathways in apoptosis of keratinocytes from perilesional vitiligo skin: Protective effects of curcumin and capsaicin

• Published in: Antioxidants & redox signaling Vol. 13; no. 9; p. 1309
• Main Authors: Becatti, Matteo, Prignano, Francesca, Fiorillo, Claudia, Pescitelli, Leonardo, Nassi, Paolo, Lotti, Torello, Taddei, Niccolò
• Format: Journal Article
• Language: English
• Published: United States 01.11.2010
• Subjects: Antioxidants - metabolism; Antioxidants - pharmacology; Apoptosis - drug effects; Capsaicin - metabolism; Capsaicin - pharmacology; Cells, Cultured; Curcumin - metabolism; Curcumin - pharmacology; Humans; Intracellular Signaling Peptides and Proteins - metabolism; Keratinocytes - cytology; Keratinocytes - drug effects; Keratinocytes - metabolism; MAP Kinase Signaling System; Melanocytes - metabolism; Mitochondria - metabolism; Mitochondrial Proteins - metabolism; NF-kappa B - metabolism; Oxidative Stress - drug effects; Oxidative Stress - physiology; p38 Mitogen-Activated Protein Kinases - antagonists & inhibitors; p38 Mitogen-Activated Protein Kinases - metabolism; Phosphorylation; Reactive Oxygen Species - metabolism; Skin - metabolism; Tumor Suppressor Protein p53 - metabolism; Vitiligo - metabolism
• ISSN: 1557-7716
• DOI: 10.1089/ars.2009.2779

Oxidative stress has been suggested as the initial pathogenetic event in melanocyte degeneration in vitiligo. Our previous results indicate that keratinocytes from perilesional skin show the features of damaged cells. In the present study, biopsies were taken from the perilesional skin of 12 patients suffering from nonsegmental vitiligo. The intracellular pathways involved in keratinocyte damage and apoptosis and the antioxidant protection of curcumin and capsaicin in these cells were investigated. In keratinocytes from perilesional vitiligo skin, we observed high levels of activated p38, NF-kB p65 subunit, p53, and Smac/DIABLO proteins. In contrast, low levels of ERK phosphorylation were present. To investigate the relationship between these pathways, we used specific inhibitors and evaluated the alteration of each pathway. For the first time, our study demonstrates the pivotal role of p38 MAP kinase as an upstream signal of perilesional keratinocyte damage, and the important contribution of p38 and NF-kB on p53 accumulation. Curcumin and capsaicin also increase ERK phosphorylation, thus inhibiting apoptosis. Moreover, pretreatment with such natural antioxidants inhibited caspase activation, increased total antioxidant capacity, repressed intracellular ROS generation and lipid peroxidation, and improved mitochondrial activity. These results suggest that antioxidants might represent an alternative approach to protect against vitiligo progression.