Ion Channel and Calcium Signaling in Ultraviolet Light Transduction in Human Skin

人体皮肤紫外线传导中的离子通道和钙信号传导

• 批准号: 8737727
• 负责人: Elena Oancea
• 金额: $ 31.05万
• 依托单位: BROWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-20 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8737727
• 关键词: 1,2-diacylglycerol; Animal Model; Binding; Biochemistry; Calcium Signaling; Cells; Coupled; Cyclic AMP; DNA; DNA Damage; Data; Diglycerides; Dose; Electrophysiology (science); Environmental Carcinogens; Epidermis; Fluorescence Microscopy; Foundations; Free Radicals; GTP-Binding Proteins; Generations; Genetic; Goals; Hour; Human; Human body; Hydrolysis; Image; Incidence; Inositol; Ion Channel; Knowledge; Lead; Life; Light; Link; Malignant Neoplasms; Mammals; Measures; Mediating; Melanins; Membrane; Molecular; Monophenol Monooxygenase; Mus; Nuclear; Organ; Organism; Pathway interactions; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Photons; Phototransduction; Physiological; Pigmentation Disorders; Pigmentation physiologic function; Process; Production; Protein Kinase C; Regulation; Reporting; Retinal; Risk Factors; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Skin; Skin Cancer; Skin Pigmentation; Solid; Sunlight; Surface; Testing; The Sun; Time; UVA induced; UVB induced; Ultraviolet B Radiation; Ultraviolet Rays; Work; age effect; base; fluorescence imaging; keratinocyte; melanocyte; melanoma; novel; oxidative damage; patch clamp; prevent; public health relevance; receptor; research study; response; therapeutic target

DESCRIPTION (provided by applicant): Skin, the largest organ of the human body, is constantly exposed to solar ultraviolet radiation (UVR), a powerful environmental carcinogen. Unlike the skin of other mammals, human skin responds to UVR by increased pigmentation resulting from melanin production in epidermal melanocytes and its transfer to keratinocytes. Melanin protects the nuclear DNA of melanocytes and keratinocytes by directly absorbing UVR and neutralizing free radicals, thus preventing genetic damage and cancer formation. How does human skin detect and respond to UVR? UVR at the earth's surface consists of 95% long wavelength UVR (UVA) and 5% short wavelength UVR (UVB). Although the mechanism by which UVB causes DNA damage and results in delayed melanin synthesis more than a day after exposure is well characterized, the effects of UVA are poorly understood. High UVA doses cause oxidative damage, but no specific pathway for detecting physiological doses of UVA has been characterized. Our preliminary results describe a novel UVA-activated signaling pathway in melanocytes that is retinal-dependent and G-protein coupled. Activation of this pathway by physiological doses of UVA leads to the activation of transient receptor potential A1 (TRPA1) ion channels, a rapid increase in intracellular Ca2+, and increased melanin content on a rapid time scale (beginning about an hour after UVA exposure). The goal of this proposal is to characterize the molecular steps by which UVA causes a Ca2+ response (Aim 1) and an increase in cellular melanin concentration (Aim 2). Using live-cell fluorescence imaging, electrophysiology, and biochemistry, we will identify in Aim1 the G protein pathway activated by UVA, characterize the cellular messengers and determine the mechanisms that lead to a rapid and transient Ca2+ response. In Aim 2 we will test the hypothesis that UVA-mediated cellular depolarization is required for a sustained Ca2+ response and persistent PKC activation, which leads to early melanin production. In Aim 3 we will test the hypothesis that UVA and UVB signaling pathways, which are simultaneously activated by solar UVR, interact synergistically to regulate melanin production and pigmentation. We will use mice with "humanized" skin to investigate the interaction between the UVA and UVB activated pathways and characterize the molecular mechanisms mediating this interaction. The proposed studies will identify and characterize a novel UVA phototransduction pathway and determine its function in skin, and will significantly advance our understanding of melanocyte function and of the skin's response to solar UVR.

描述（由申请人提供）：皮肤是人体最大的器官，经常暴露于太阳紫外线辐射（UVR），这是一种强大的环境致癌物。与其他哺乳动物的皮肤不同，人类皮肤对UVR的反应是表皮黑素细胞中黑色素的产生及其转移到角质形成细胞导致色素沉着增加。黑色素通过直接吸收紫外线和中和自由基来保护黑素细胞和角质形成细胞的核DNA，从而防止遗传损伤和癌症形成。人体皮肤如何检测和响应紫外线？地球表面的UVR由95%的长波UVR（UVA）和5%的短波UVR（UVB）组成。虽然UVB引起DNA损伤并导致暴露后超过一天的黑色素合成延迟的机制得到了很好的表征，但UVA的影响却知之甚少。高剂量的UVA会引起氧化损伤，但没有特定的途径来检测UVA的生理剂量。我们的初步结果描述了一种新的UVA激活的信号通路在黑素细胞，视网膜依赖性和G蛋白耦合。通过生理剂量的UVA激活该途径导致瞬时受体电位A1（TRPA1）离子通道的激活，细胞内Ca2+的快速增加，以及在快速时间尺度上（在UVA暴露后约1小时开始）增加的黑色素含量。本提案的目的是表征UVA引起Ca2+反应（目标1）和细胞黑色素浓度增加（目标2）的分子步骤。使用活细胞荧光成像，电生理学和生物化学，我们将确定在Aim 1中由UVA激活的G蛋白通路，表征细胞信使，并确定导致快速和瞬时Ca2+反应的机制。在目标2中，我们将测试的假设，UVA介导的细胞去极化需要持续的Ca2+反应和持续的PKC激活，这导致早期黑色素的生产。在目标3中，我们将测试的假设，UVA和UVB信号通路，这是同时激活太阳紫外线辐射，相互作用，协同调节黑色素的产生和色素沉着。我们将使用具有“人源化”皮肤的小鼠来研究UVA和UVB激活途径之间的相互作用，并表征介导这种相互作用的分子机制。拟议的研究将确定和表征一种新的UVA光转导途径，并确定其在皮肤中的功能，并将显着推进我们对黑素细胞功能和皮肤对太阳紫外线的反应的理解。