Characterization of a ultraviolet B-induced corticotropin-releasing hormone-proopiomelanocortin system in human melanocytes.
Characterization of a ultraviolet B-induced corticotropin-releasing hormone-proopiomelanocortin system in human melanocytes.
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DOI：
10.1210/me.2006-0116
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发表时间：
2006-10
影响因子：
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通讯作者：
B. Zbytek;J. Wortsman;A. Slominski
中科院分区：
文献类型：
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作者：
B. Zbytek;J. Wortsman;A. Slominski
CRH是全身应激反应的主要调节因子，它也在皮肤中表达，并与下丘脑-垂体-肾上腺轴的局部同源物结合。为了研究在人黑素细胞中诱导CRH-proopiomelanocortin （POMC）反应的机制，我们使用UVB作为表皮特异性应激源。用分级剂量的UVB照射体外培养的人正常黑色素细胞，并在细胞提取物和/或上清液中测量CRH-POMC反应。UVB刺激CRH启动子、CRH mRNA表达和肽释放。uvb诱导的CRH启动子的刺激被蛋白激酶A的药理学抑制剂或过表达显性突变cAMP反应元件（CRE）结合蛋白（CREB）的质粒所抑制。UVB还刺激了CREB的磷酸化，磷酸化的CREB与CRH启动子中的CRE位点结合，以及由共识CRE位点驱动的报告基因构建的活性。在正常和恶性黑色素细胞中，CRH启动子中CRE位点的突变使相应的报告基因结构对UVB的反应减弱。除了对CRH的影响外，UVB还激活了POMC启动子、POMC mRNA表达和ACTH释放，而CRH受体1的拮抗剂则消除了UVB刺激对POMC的诱导。综上所述，UVB通过刺激蛋白激酶A途径诱导人黑素细胞产生CRH， CRH-CRH受体1依次参与刺激POMC表达。
CRH, the main regulator of the systemic response to stress, is also expressed in the skin where it is incorporated into a local homolog of the hypothalamic-pituitary-adrenal axis. To investigate the mechanisms of the induction of the CRH-proopiomelanocortin (POMC) response in human melanocytes, we used UVB as an epidermal-specific stressor. Human normal melanocytes cultured in vitro were irradiated with graded doses of UVB, and the CRH-POMC responses were measured in cell extracts and/or supernatants. UVB stimulated the CRH promoter, the CRH mRNA expression, and peptide release. The UVB-induced stimulation of the CRH promoter was suppressed by pharmacological inhibitors of protein kinase A or by plasmid overexpressing a dominant mutant cAMP response element (CRE)-binding protein (CREB). UVB also stimulated phosphorylation of CREB, binding of phosphorylated CREB to CRE sites in the CRH promoter, and activity of the reporter gene construct driven by consensus CRE sites. Mutation in the CRE site in the CRH promoter rendered the corresponding reporter gene construct less responsive to UVB in both normal and malignant melanocytes. In addition to CRH effects, UVB activated the POMC promoter, POMC mRNA expression, and ACTH release, whereas an antagonist of the CRH receptor 1 abrogated the UVB-stimulated induction of POMC. In conclusion, UVB induces CRH production in human melanocytes through stimulation of the protein kinase A pathway, with sequential involvement of CRH-CRH receptor 1 in the stimulation of POMC expression.