The Effect of Dehydroepiandrosterone on Expression of Elastin in Cultured Skin Fibroblasts / 대한피부과학회지

BACKGROUND: Dehydroepiandrosterone(DHEA) and its sulfate ester dehydro- epiandrosterone sulfate(DHEA-S) are the steroids secreted most abdundantly by the human adrenal gland, but the physiologic role remains uncertain. Elastin is one of the major extracellular matrix components of the dermis and plays an important role in providing elasticity and resilience of the skin. Expression of elastin genes at transcriptional level is regulated and modulated by cytokines, vitamin D3, insulin-like growth factor-1, and steroids. But only little is known about the molecular and cellular mechanism underlying the effect of DHEA on the expression of elastin in cultured skin fibroblasts. OBJECTIVE: The purpose of this study was to examine the effect of DHEA on elastin gene expression in cultured skin fibroblasts. METHODS: In this study, the effects of DHEA were examined by Northern blot hybridization, chloramphenicol acetyltransferase assay(CAT), and laser scanning microscopy in cultured human fibroblasts. RESULTS: In Northern blot hybridization, levels of elastin mRNA were increased 1.5-fold at 1 nmol of DHEA, 4.2-fold at 0.1 mol and 6.5-fold at 10 mol, compared to untreated control. DHEA caused a alteration in the elastin mRNA expression in a dose-related fashion. In CAT assay, the relative mRNA CAT activity was 0.9 at a concentration of 1 nmol, 2.4 at 0.1 mol, and 2.7 at a 10 mol. DHEA caused a marked increase on elastin promotor activity. In confocal laser scanning microscopy, the immunosignal for elastin in DHEA-treated fibroblasts is more intense compared to the control. CONCLUSION: These results indicate that DHEA may be a powerful up-regulator of elastin production, suggesting transcriptional activation of gene expression in cultured skin fibroblasts.

The Effect of Nicotine on Elastin Gene Expression in Cultured Skin Fibroblasts / 대한피부과학회지

BACKGROUND: The elastic fibers are a major fibrillar component of the extracellular matrix of several organs, and their presence provides elastic properties to these tissues. A variety of cytokines, growth factors, and hormones have been shown to modulate elastin gene expression. So far most interest increased the effects of external environment on elastin metabolism in the skin. It has become generally accepted that cigarette smoking contributes to accelerated coronary and peripheral vascular disease, pulmonary fibrosis and periodontal disease. Nicotine is a major component of the particulate phase of tobacco smoke. OBJECTIVE: Only little is known about the molecular and cellular mechanism underlying the effect of nicotine on the skin fibroblasts. Our study was performed to determine the effects of nicotine on elastin gene expression. METHOD: In this study, the effects of nicotine were examined by Northern blot hybridization, chloramphenicol acetyltransferase (CAT) assay, and laser scanning microscopy in cultured human fibroblasts. RESULTS: In Northern blot hybridization, steady-state levels of elastin mRNA were decreased 0.9-fold at 1 microgram/mL of nicotine, 0.7-fold at 10 microgram/mL and 0.5-fold at 100 microgram/mL, compared to untreated control. Nicotine caused a marked alteration in the elastin mRNA expression in a dose-related fashion. In CAT assay, the relative elastin CAT activity was 1.0 in the untreated control, 0.9 at a concenturation of 1 microgram/mL, 0.3 at 10 microgram/mL, and 0.2 at 100 microgram/mL. Nicotine caused a marked decrease on elastin promoter activity. In laser scanning microscopy, the immunosignal for elastin in nicotine-treated fibroblasts shows in less intense than in untreated control. CONCLUSION: These results indicate that nicotine may be a powerful down-regulator of elastin production, suggesting transcriptional depression of gene expression in cultured skin fibroblasts.