Sex Steroid Regulation of Melanocyte Homeostasis

 描述(申请人提供)：影响黑素细胞色素产生和增殖的因素复杂且知之甚少，但人类黑素细胞和表皮色素痣(葡萄胎)在怀孕期间发生的变化提供了一些线索。虽然已经假设性类固醇激素影响这些过程，但调节任何黑素细胞效应的特定激素、受体和下游信号通路在很大程度上是未知的。我的初步结果表明，几种与怀孕相关的性类固醇激素显著改变了黑色素细胞的色素生成和细胞增殖率。我的初步数据显示，雌激素和黄体酮相互调节黑色素的产生。雌激素促进黑色素的产生，而黄体酮则减少黑色素的产生。这些激素的作用可能是通过非经典受体，而不是经典的类固醇激素受体，我已经确定后者在黑素细胞中不表达。其他初步研究结果表明，妊娠相关的孕激素，别孕酮，促进增殖，防止关键的BRAF(V600E)生长停止，这是良性痣向黑色素瘤转变的关键步骤。本建议中所描述的实验旨在：1：阐明雌激素和孕激素影响正常色素形成的信号机制；2：确定别孕酮信号对黑色素瘤发生的影响，并确定别孕酮发挥作用的特定受体和途径。在培养的黑素细胞中，使用shRNA去除GPER和PAQR7可以阻止雌激素和孕激素的各自作用。Aim IA的目标是确定GPER和PAQR7信号在调节器官型人体组织中的性激素效应的必要性和充分性，而Aim IB的目标是确定GPER和PAQR7影响黑色素产生的机制。别孕酮可增加黑素细胞的增殖率并绕过BRAF(V600E)诱导的黑素细胞生长停滞。目的IIA旨在确定别孕酮促进增殖和生长抑制旁路的机制，AIM IIB旨在确定别孕酮信号在黑色素瘤发生中的作用。我提议的工作将确定妊娠相关性类固醇激素影响黑素细胞稳态的机制，并可能确定妊娠期间色素沉着障碍和黑色素瘤的新治疗靶点。

 DESCRIPTION (provided by applicant): Factors influencing melanocyte pigment production and proliferation are complex and poorly understood, but some clues are suggested by changes that occur in both human melanocytes, and epidermal nevi (moles) during pregnancy. While it has been assumed that sex-steroid hormones influence these processes, the specific hormones, receptors, and downstream signaling pathways mediating any melanocyte effect are largely undefined. My preliminary results suggest that several pregnancy-associated sex steroid hormones significantly alter both melanocyte pigment production and cellular proliferation rate. My preliminary data indicates that estrogen and progesterone reciprocally regulate melanin production. Estrogen promotes melanin production, while progesterone decreases melanin production. The effects of these hormones are likely through nonclassical receptors rather than the classical steroid hormone receptors, which I have determined are not expressed in melanocytes. Additional preliminary findings suggest that the pregnancy associated progestin, allopregnanolone, increases proliferation and prevents the critical BRAF (V600E) growth-arrest, which is an essential step for the transition of benign nevus to melanoma. The experiments described in this proposal aim to 1: elucidate the signaling mechanisms through which estrogen and progesterone influence normal pigmentation, and 2: define the influence of allopregnanolone signaling on melanoma development, and identify the specific receptors and pathways through which allopregnanolone exerts its effect. In cultured melanocytes, depletion of GPER and PAQR7 using shRNA prevents the respective estrogen and progesterone effects. The goal of Aim IA is to determine the necessity and sufficiency of GPER and PAQR7 signaling to mediate the sex hormone effects in organotypic human tissue, and the goal of Aim IB is to determine the mechanisms through which GPER and PAQR7 influence melanin production. Allopregnanolone increases the proliferation rate and bypasses the BRAF (V600E) induced growth arrest in cultured melanocytes. Aim IIA is designed to determine mechanisms through which allopregnanolone promotes proliferation and growth-arrest bypass, and Aim IIB is designed to define the contribution of allopregnanolone signaling on melanoma development. My proposed work will determine the mechanisms through which pregnancy-associated sex steroid hormones influence melanocyte homeostasis, and may identify new therapeutic targets for pigmentation disorders and melanoma during pregnancy.