Sex Steroid Regulation of Melanocyte Homeostasis

 描述（由申请人提供）：影响黑素细胞色素产生和增殖的因素很复杂，而且了解得很少，但妊娠期间人类黑素细胞和表皮痣（痣）发生的变化提示了一些线索。虽然已经假设性类固醇激素影响这些过程，但介导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不确定的。我的初步结果表明，几个怀孕相关的性类固醇激素显着改变黑色素细胞的色素生产和细胞增殖率。我的初步数据表明，雌激素和孕激素共同调节黑色素的产生。雌激素促进黑色素的产生，而孕酮减少黑色素的产生。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，我已经确定不表达在黑素细胞。额外的初步研究结果表明，妊娠相关的孕激素，allopregnanolone，增加增殖，并防止关键的BRAF（V600 E）生长停滞，这是良性痣向黑色素瘤转变的重要步骤。本提案中描述的实验旨在1：阐明雌激素和孕激素影响正常色素沉着的信号传导机制，2：定义别孕烯醇酮信号传导对黑色素瘤发展的影响，并确定别孕烯醇酮发挥作用的特异性受体和途径。在培养的黑素细胞中，使用shRNA消耗GPER和PAQR 7可以阻止各自的雌激素和孕激素效应。目的IA的目标是确定GPER和PAQR7信号传导介导器官型人类组织中的性激素效应的必要性和充分性，目的IB的目标是确定GPER和PAQR7影响黑色素产生的机制。别孕烯醇酮增加增殖速率并绕过BRAF（V600E）诱导的培养黑素细胞生长停滞。目的IIA旨在确定通过其allopregnanolone促进增殖和生长停滞旁路的机制，目的IIB旨在定义allopregnanolone信号传导对黑色素瘤发展的贡献。我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，并可能确定妊娠期色素沉着疾病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.