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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Active Transport, Cell Nucleus, Cell Line, Cell Nucleus, Fibroblasts, Gene Expression Regulation, Enzymologic, Humans, Keratinocytes, Matrix Metalloproteinase 1, Matrix Metalloproteinase 3, Matrix Metalloproteinase 9, Sunscreening Agents, Ultraviolet Rays, beta Catenin.
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Is uVA-activated synthesis of metalloproteinases 1 , 3 and 9 prevented by a broad-spectrum sunscreen? Context: Specific sunscreens against ultraviolet (UV) A and B radiations are essential to prevent matrix degradation and the activation of intracellular signaling pathways involved in photoaging and photocarcinogenesis. Matrix degradation results from UVA-induced production of matrix metalloproteinases (MMP) and activation of intracellular pathways in fibroblasts and keratinocytes. In particular, in keratinocytes, UVA radiation induces β-catenin nuclear translocation and stimulates MMP gene transcription. Our study was aimed at assessing the efficacy of a specific broad-spectrum sunscreen in preventing β-catenin translocation and MMPs enhanced expression in cultured keratinocytes after UVA irradiation. Sunscreen or the vehicle was spread on quartz sheet. Irradiation of HaCaT cells with 6 J/cm(2) UVA was performed through the sheet, and cells were collected for β-catenin immunostaining then visualization by confocal microscopy, and quantitative real-time polymerase chain reaction analysis of MMP-1, -3 and -9 gene expression. As shown by immunostaining and confocal microscopy, the sunscreen abrogated UVA-induced beta-catenin translocation to the nucleus, in comparison with control groups. MMP-1, -3 and -9 mRNA expression was enhanced by 7, 7 and 4 folds (P < 0.0001, P < 0.001 and P < 0.01, respectively) in unprotected UVA-irradiated cells compared to the non-irradiated control. Sunscreen protection of the cells significantly reduced UVA-induced expression of MMP-1, -3 and -9 by 83% (P < 0.01), 80% (P < 0.01) and 65% (P < 0.05), respectively.
assistant
This study demonstrated the efficacy of this broad-spectrum sunscreen in preventing UVA-induced effects on the markers of photoaging and photocarcinogenesis in vitro. It was able to protect HaCaT keratinocytes from UVA-induced β-catenin translocation to the nucleus and MMPs expression. Final Decision: yes