UV-induced and NOS-mediated Zn elevation, translation regulation and apoptosis

描述（由申请人提供）：在美国，每年诊断出超过100万例非黑色素瘤皮肤癌和59，600例黑色素瘤，2005年导致约10，600例死亡（约7，800例死于黑色素瘤）。近年来，已经清楚的是，紫外线损伤的皮肤具有增加的机会发展成皮肤癌的一种形式，包括基底细胞癌、鳞状细胞癌和皮肤恶性黑色素瘤。对UV的凋亡反应是一种保护性反应，其消除了接受高剂量UV的细胞。虽然大多数研究都集中在DNA损伤诱导的，p53依赖的途径紫外线诱导的细胞凋亡，膜受体介导的信号转导途径也发挥重要作用，在诱导细胞凋亡。紫外线照射激活磷酸化真核起始因子2（eIF 21）α亚基的激酶，随后抑制蛋白质合成。翻译在凋亡基因表达调控中起重要作用。然而，导致eIF 21激酶在UV照射后活化的上游信号传导途径尚不清楚。本申请的目的是阐明通过一氧化氮合酶（NOS）介导的信号通路调节UV诱导的细胞凋亡的机制，并确定一氧化氮（NO）/过氧亚硝酸盐（ONOO）和锌（Zn 2+）在UV诱导的翻译调节和细胞凋亡中的作用。本申请中提出的研究是重要的，因为了解NOS激活的调节以及这种调节如何影响UV照射后eIF 21激酶的激活和/或凋亡将使我们找到一种新的信号传导网络，用于鉴定靶基因和开发预防和治疗UV相关癌症的疗法。在特定目标I中，我们提出阐明导致eIF 21磷酸化的UV诱导和NO介导的信号通路。工作假设是NO介导UV诱导的eIF 21激酶的激活，其使eIF 21磷酸化。在具体目标II中：我们提出确定NO/ONOO/产生的机制和动力学及其在UV诱导的细胞凋亡中的作用。工作假设是，在NO：ONOO的高比率下，UV的作用可以是抗凋亡的，而在低比率下，这种作用可以是促凋亡的。在特定目标III中，我们提出确定Zn在UV诱导的ER应激和凋亡信号通路中的作用。工作假设是[Zn 2 +]介导UV照射后NO诱导的细胞凋亡。这项研究的结果不仅将增加我们对UV诱导和NOS介导的多种信号传导途径的了解，而且还将导致对其他生理条件诱导的调节机制和信号传导途径的进一步理解（例如，再灌注、伤口愈合、糖尿病），其受到NO和翻译抑制的影响。公共卫生相关性：紫外线（UV）诱导的细胞死亡是一种消除受损细胞的保护性反应。在这个计划中，我们将研究通过一氧化氮合酶介导的信号通路调节UV诱导的细胞凋亡的机制，并确定一氧化氮/过氧亚硝酸盐和细胞溶质锌浓度在UV诱导的翻译调节和细胞凋亡中的作用。这些研究的结果不仅将增加我们对UV诱导的多种凋亡信号通路的了解，而且还将引导我们开发用于治疗UV相关皮肤老化和癌症的新疗法。

DESCRIPTION (provided by applicant): More than 1 million cases of nonmelanoma skin cancer and 59,600 cases of melanoma are diagnosed yearly in the United States, resulting in about 10,600 deaths (about 7,800 due to melanoma) in 2005. In recent years it has become clear that UV-damaged skin has an increased chance of developing one of the forms of skin cancer, including basal cell carcinoma, squamous cell carcinoma and cutaneous malignant melanoma. The apoptotic response to UV is a protective response that eliminates cells that receive high doses of UV. While most studies have focused on DNA damage-inducible, p53-dependent pathways of UV-induced apoptosis, membrane receptor mediated signaling pathways also play an important role in inducing apoptosis. UV-irradiation activates kinases that phosphorylate the alpha subunit of eukaryotic initiation factor 2 (eIF21) and subsequently inhibit protein synthesis. Translation plays an important role in regulation of apoptotic gene expression. However, the upstream signaling pathway(s) that leads to eIF21 kinase(s) activation upon UV-irradiation is not known. The objective of this application is to elucidate the mechanisms that regulate UV-induced apoptosis via nitric oxide synthase (NOS) mediated signaling pathways and to determine the roles of nitric oxide (NO)/peroxynitrite (ONOO) and zinc (Zn2+) in UV-induced translation regulation and apoptosis. The research proposed in this application is significant because understanding the regulation of NOS activation and how this regulation affects eIF21 kinase(s) activation and/or apoptosis upon UV-irradiation will lead us to a new signaling network for identification of target genes and development of therapeutics in the prevention and treatment of UV-related cancers. In Specific Aim I, we proposed to elucidate the UV-induced and NO-mediated signaling pathway(s) that leads to eIF21 phosphorylation. The working hypothesis is that NO mediates UV-induced activations of eIF21 kinase(s), which phosphorylate eIF21. In Specific Aim II: we proposed to determine the mechanism and kinetics of NO/ONOO/ production and their role in UV-induced apoptosis. The working hypothesis is that at a high ratio of NO:ONOO, the effect of UV can be anti-apoptotic, while at a low ratio this effect can be pro-apoptotic. In Specific Aim III, we proposed to determine the role(s) of Zn in UV-induced ER-stress and apoptotic signaling pathways. The working hypothesis is that [Zn2+] mediates NO-induced apoptosis upon UV- irradiation. The outcomes from this research will not only increase our knowledge of UV- induced and NOS-mediated multiple signaling pathways, but will also lead to a further understanding of regulatory mechanisms and signaling pathways induced by other physiological conditions (e.g., reperfusion, wound healing, diabetes) that are affected by NO and translation inhibition. PUBLIC HEALTH RELEVANCE: Cell death induced by ultraviolet light (UV) is a protective response that eliminates damaged cells. In the proposal, we will study the mechanisms that regulate UV-induced apoptosis via nitric oxide synthase mediated signaling pathways and to determine the roles of nitric oxide/peroxynitrite and cytosolic zinc concentration in UV-induced translation regulation and apoptosis. The outcomes from these studies will not only increase our knowledge of UV- induced multiple apoptotic signaling pathways, but will also lead us to the development of new therapeutics for treatment of UV-related skin aging and cancers.