Linking Lipoxygenases with Essential Fatty Acids and Epidermal Barrier Formation

将脂氧合酶与必需脂肪酸和表皮屏障的形成联系起来

• 批准号: 8906464
• 负责人: ALAN R. BRASH
• 金额: $ 35.1万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8906464
• 关键词: Anabolism; Animal Model; Area; Atopic Dermatitis; Ceramides; Characteristics; Cleaved cell; Clinical; Congenital ichthyosis; Coupling; Defect; Disease; Enzymes; Epidermis; Essential Fatty Acids; Esters; Family; Family suidae; Fatty Acids; Foundations; Functional disorder; Future; Goals; Human; Hydrolase; Hydrolysis; Hydroxyl Radical; Ichthyoses; Inherited; Knockout Mice; Left; Link; Linoleic Acids; Lipids; Lipoxygenase; Modeling; Molecular; Mus; Mutate; Mutation; Oxidants; Patients; Phenotype; Physiology; Process; Role; Skin; Structure; Testing; Therapeutic; Therapeutic Intervention; Topical application; Very Long Chain Fatty Acid; Water; analog; base; chemical synthesis; crosslink; design; enzyme substrate; esterase; in vivo; link protein; lipoxygenase 3; psychologic; public health relevance; seal; skin disorder; social

DESCRIPTION (provided by applicant): The long-term objective of this application is to elucidate the roles of two lipoxygenase (LOX) enzymes and their essential fatty acid (EFA) substrate in forming the water impermeable barrier of the epidermis, defects in which result in ichthyoses and contribute to atopic dermatitis. 12R-Lipoxygenase (12R-LOX) and Epidermal Lipoxygenase-3 (eLOX3) are the only human lipoxygenases that, if mutated to inactive forms, result in a disease, a form of autosomal recessive congenital ichthyosis (ARCI). The fact that the characteristic scaly skin of ARCI is also manifest in essential fatty acid (EFA) deficiency, suggests a possible substrate-enzyme relationship between EFA and the two LOX enzymes. We will test a new hypothesis that connects EFA, 12R- LOX and eLOX3, and the structure of the epidermal water barrier. We propose that the two lipoxygenases oxygenate a critical form of EFA, linoleate esterified to the omega-hydroxyl of the very long chain fatty acid of the unique epidermal acylceramides. We further propose that this oxygenation is required to facilitate hydrolysis of the (oxidized) linoleate moiety and leave the very long chain fatty acid omega-hydroxyl free for coupling to the cross-linked proteins of the corneocyte envelope, a vital step in sealing the water barrier. The Specific Aims are (1) To characterize 12R-LOX and eLOX3 activity in the epidermis in vivo using animal models, (2) To assess the efficacy of LOX products and ceramides in rescuing the phenotype in murine LOX-/- models, (3) To characterize 12R-LOX and eLOX3 activity in human epidermis including in ARCI patients, and (4) To characterize the putative oxidant-sensitive step of acylceramide ester hydrolysis. The results of this study wil piece together an important facet of construction of the epidermal water barrier and allow a rational approach to the use of oxidized linoleate and its analogs for future therapeutic interventions in the LOX- dependent classes of ichthyoses. If the physiology of the barrier is properly understood, this constitutes a firm foundation for the rational design of any barrier-related therapeutics, and it is to rationalize the role of these well-known key components of the epidermal water barrier that is the main goal of this project.

描述(申请人提供)：本申请的长期目标是阐明两种脂氧合酶(LOX)酶及其必需脂肪酸(EFA)底物在形成表皮水不透水屏障中的作用，这种缺陷会导致鱼鳞病和特应性皮炎。12R-脂氧合酶(12R-LOX)和表皮脂氧合酶-3(ELOX3)是人类仅有的两种脂氧合酶，如果突变为非活性形式，会导致一种常染色体隐性遗传性先天性鱼鳞病(ARCI)。事实上，ARCI特有的鳞片状皮肤也表现为必需脂肪酸(EFA)缺乏，这表明EFA和这两种LOX酶之间可能存在底物-酶关系。我们将测试一个新的假设，连接EFA，12R-LOX和eLOX3，以及表皮水屏障的结构。我们认为，这两种脂氧合酶氧化了EFA的一种关键形式，亚油酸酯化为独特的表皮酰神经酰胺的超长链脂肪酸的欧米伽-羟基。我们进一步提出，这种氧合作用是为了促进(氧化的)亚油酸部分的水解，并使超长链脂肪酸欧米伽-羟基自由偶联到角膜细胞被膜的交联蛋白上，这是在 封堵水屏障。其具体目的是(1)利用动物模型确定活体表皮中12R-LOX和eLOX3的活性，(2)评估LOX产品和神经酰胺在挽救小鼠LOX-/-模型表型方面的有效性，(3)表征包括ARCI患者在内的人类表皮中12R-LOX和eLOX3的活性，以及(4)表征推测的酰神经酰胺酯水解氧化敏感步骤。这项研究的结果将整合构建表皮水屏障的一个重要方面，并允许合理地使用氧化亚油酸及其类似物，用于未来对LOX依赖类鱼鳞病的治疗干预。如果正确了解屏障的生理学，这将为任何屏障相关疗法的合理设计奠定坚实的基础，而本项目的主要目标是使这些众所周知的表皮水屏障关键成分的作用合理化。