Impact of MC1R Functional Variants on the DNA Damage Response of Human Melanocyte

MC1R 功能变异对人黑素细胞 DNA 损伤反应的影响

• 批准号: 8069824
• 负责人: ZALFA ABDEL-MALEK
• 金额: $ 32.47万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-20 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8069824
• 关键词: 8-hydroxy-2' -deoxyguanosine; ATF2 gene; Affect; Alleles; Animal Model; Antioxidants; Apoptosis; Binding; Biological; Biological Assay; Biopsy; CDK4 gene; Cells; Clinic; Clinical; Code; Corticotropin; Cyclic AMP; DNA Damage; DNA Repair; DNA Repair Gene; Data; Deoxyguanosine; Development; ERCC1 gene; Early Diagnosis; Endothelin-1; Enzymes; Epidemiologic Studies; Etiology; Experimental Models; Exposure to; Failure; Fibroblast Growth Factor 2; Gene Expression; Gene Targeting; Generations; Genes; Genetic Variation; Genome Stability; Genotype; Glutathione S-Transferase; Goals; Hair; Health; Heterozygote; Human; Incidence; Individual; Knowledge; Laboratories; Lead; Ligand Binding; Link; MAPK14 gene; MAPK3 gene; MAPK8 gene; Maintenance; Measures; Mediating; Melanocyte stimulating hormone; Melanogenesis; Mitogen Activated Protein Kinase 1; Mitogen-Activated Protein Kinases; Molecular Genetics; Monophenol Monooxygenase; Mus; NAD(P)H dehydrogenase (quinone) 1, human; NADP; Nucleotide Excision Repair; Oxidative Stress; POMC gene; Pathway interactions; Patients; Phenotype; Phosphorylation; Physiological; Pigmentation physiologic function; Population; Predisposition; Prevention; Prevention strategy; Principal Investigator; Property; Pyrimidine Dimers; Reactive Oxygen Species; Receptor Gene; Receptor Signaling; Recording of previous events; Regulation; Research; Research Personnel; Resources; Response Elements; Risk; Risk Assessment; Risk Factors; Role; SAPK; Signal Pathway; Signal Transduction; Skin; Skin Cancer; Skin Substitutes; Skin tanning; Staining method; Stains; Sunburn; Susceptibility Gene; Transfection; Translating; UV induced; UV induced DNA damage; UV response; Ultraviolet Rays; Variant; XPA gene; activating transcription factor; advanced disease; alpha-Melanocyte stimulating hormone; annexin A5; base; cancer risk; caspase-3; clinical application; clinical phenotype; cohort; common cellular transcription factor ATF; effective therapy; eumelanin; gene function; heme oxygenase-1; improved; innovation; irradiation; loss of function; melanocortin receptor; melanocyte; melanoma; mitogen-activated protein kinase p38; novel; outcome forecast; oxidative DNA damage; paracrine; patient population; peroxiredoxin I; photoprotection; prevent; receptor; receptor binding; receptor function; reconstitution; repaired; research study; response; restoration; skin cancer prevention; transcription factor; transcription factor USF; ultraviolet damage; ultraviolet irradiation

DESCRIPTION (provided by applicant): The melanocortin 1 receptor gene (MC1R) is a main contributor to the diversity of human pigmentation. The activated MC1R stimulates eumelanin synthesis, and enhances nucleotide excision repair and antioxidant responses in UV-irradiated human melanocytes, thus reducing the risk for melanoma. Functional variants of MC1R disrupt receptor function and alter the pigmentary phenotype by varying extents. We propose to investigate the hypothesis that MC1R functional variants increase melanoma risk by disrupting MC1R signaling, leading to impaired UV-induced DNA damage response of human melanocytes via compromising their DNA repair, antioxidant and melanogenic capacities. The effects of most MC1R variants on the function of the melanocyte are poorly understood. Given the lack of an appropriate animal model for human pigmentation, the unique properties of the human MC1R, and the role of human melanocytes in photoprotection, it is critical to investigate the impact and establish causality of common human MC1R variants in the aberrant UV response, using human melanocytes that naturally express this gene and are a physiological target for melanocortins. A unique resource available to us is a cohort of patients with known MC1R genotype, pigmentary phenotype, and clinical history and risk factors for melanoma, which will allow us to correlate the MC1R genotype with phenotype. Melanocyte cultures will be established from skin biopsies taken from these patients. A major strength of this application is the complementary expertise of the Principal Investigators, Dr. Abdel-Malek, a pioneer in the research on melanocortins and human pigmentation, and Dr. Leachman, an expert in the molecular, genetic, and clinical aspects of melanoma, and the unique expertise of the co-Investigators and collaborators. Three Specific Aims are proposed to link the function of the MC1R to its main signaling pathway, the cAMP pathway, and to the UV-induced MAP kinase pathway, which regulates critical biological endpoints that determine melanomagenesis, namely DNA repair, antioxidant defenses and melanogenesis. In Specific Aim 1, we will compare how specific MC1R variants affect MC1R function by reducing ligand binding and/or signaling by failure to increase cAMP synthesis that activates the main signaling pathway for melanocortins. In Specific Aim 2, we will investigate in UV-irradiated melanocytes the impact of different MC1R variants on the MAP kinases and three of their downstream transcription factors NRF2, ATF2 and USF-1 that regulate the expression of antioxidant genes, DNA repair and apoptosis genes, and the pigmentary genes POMC, MC1R, and tyrosinase, respectively. In Specific Aim 3, we will determine how different MC1R variants expressed in human melanocytes affect the UV-induced levels and repair rates of cyclobutane pyrimidine dimers and 8-hydroxy-deoxyguanosine, generation of reactive oxygen species, and stimulation of melanogenesis in cultured melanocytes and skin substitutes. These studies will improve risk assessment of melanoma susceptible individuals and development of effective strategies for melanoma prevention and early detection. PUBLIC HEALTH RELEVANCE: Relevance Melanoma, the most fatal form of skin cancer, represents a major clinical challenge due to the poor prognosis and absence of an effective treatment for advanced disease. The incidence of melanoma continues to increase annually, underscoring the importance of its prevention and early detection. Our long term goal is to utilize the MC1R genotype as a marker for skin cancer, particularly melanoma, susceptibility, and to target activation of the relevant MC1R pathways for skin cancer prevention, beginning with our already assembled cohort of patience. Our elucidation of the impact of different MC1R functional variants on the function of the MC1R and the response of human melanocytes to melanocortins and UV should allow us to translate our research findings into these important clinical applications.

描述（由申请人提供）：黑皮质素1受体基因（MC1R）是人类色素沉着多样性的主要贡献者。激活的 MC1R 刺激真黑色素合成，并增强紫外线照射的人类黑色素细胞中的核苷酸切除修复和抗氧化反应，从而降低黑色素瘤的风险。 MC1R 的功能变异会破坏受体功能并不同程度地改变色素表型。我们建议研究以下假设：MC1R 功能变异通过破坏 MC1R 信号传导来增加黑色素瘤风险，从而损害人类黑色素细胞的 DNA 修复、抗氧化和黑色素生成能力，从而导致紫外线诱导的人类黑色素细胞 DNA 损伤反应受损。大多数 MC1R 变体对黑素细胞功能的影响知之甚少。鉴于缺乏合适的人类色素沉着动物模型、人类 MC1R 的独特性质以及人类黑素细胞在光保护中的作用，使用自然表达该基因且作为黑皮质素生理靶标的人类黑素细胞来研究常见人类 MC1R 变异对异常紫外线反应的影响并确定其因果关系至关重要。我们可以利用的一个独特资源是一组已知 MC1R 基因型、色素表型以及黑色素瘤临床病史和危险因素的患者，这将使我们能够将 MC1R 基因型与表型相关联。将从这些患者的皮肤活检中建立黑素细胞培养物。该应用的主要优势在于首席研究员 Abdel-Malek 博士（黑皮质素和人类色素沉着研究的先驱）和 Leachman 博士（黑色素瘤分子、遗传和临床方面的专家）的互补专业知识，以及共同研究人员和合作者的独特专业知识。提出了三个具体目标，将 MC1R 的功能与其主要信号传导途径、cAMP 途径和紫外线诱导的 MAP 激酶途径联系起来，后者调节决定黑色素瘤生成的关键生物学终点，即 DNA 修复、抗氧化防御和黑素生成。在特定目标 1 中，我们将比较特定 MC1R 变体如何通过减少配体结合和/或无法增加激活黑皮质素主要信号传导途径的 cAMP 合成来影响 MC1R 功能。在具体目标 2 中，我们将在紫外线照射的黑素细胞中研究不同 MC1R 变体对 MAP 激酶及其三个下游转录因子 NRF2、ATF2 和 USF-1 的影响，这些转录因子分别调节抗氧化基因、DNA 修复和凋亡基因以及色素基因 POMC、MC1R 和酪氨酸酶的表达。在具体目标 3 中，我们将确定人类黑素细胞中表达的不同 MC1R 变体如何影响紫外线诱导的环丁烷嘧啶二聚体和 8-羟基脱氧鸟苷的水平和修复率、活性氧的产生以及培养黑素细胞和皮肤替代品中黑素生成的刺激。这些研究将改善对黑色素瘤易感人群的风险评估，并制定有效的黑色素瘤预防和早期检测策略。公众健康相关性：相关性黑色素瘤是最致命的皮肤癌，由于预后不良且缺乏针对晚期疾病的有效治疗方法，因此成为一项重大的临床挑战。黑色素瘤的发病率每年持续增加，凸显了预防和早期发现的重要性。我们的长期目标是利用 MC1R 基因型作为皮肤癌（特别是黑色素瘤）易感性的标志物，并从我们已经组建的耐心队列开始，以激活相关 MC1R 通路来预防皮肤癌。我们阐明了不同 MC1R 功能变异对 MC1R 功能的影响以及人类黑素细胞对黑皮质素和紫外线的反应，这应该使我们能够将我们的研究结果转化为这些重要的临床应用。