Methionine sulfoxide reduction, selenium and aging

蛋氨酸亚砜还原、硒与衰老

• 批准号: 6558432
• 负责人: Vadim N. Gladyshev
• 金额: $ 25.38万
• 依托单位: UNIVERSITY OF NEBRASKA LINCOLN
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-01-15 至 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6558432
• 关键词: SDS polyacrylamide gel electrophoresis; aging; antioxidants; gene expression; gene targeting; genetically modified animals; isozymes; laboratory mouse; mass spectrometry; methionine; northern blottings; oxidative stress; oxidoreductase; polymerase chain reaction; protein structure function; reduction; selenium; sulfoxide; transfection; western blottings

DESCRIPTION (provided by applicant): Methionine sulfoxide (Met(O)) reduction is an essential metabolic pathway that provides protection against oxidative stress and regulates protein function. Met(O) are formed in the presence of reactive oxygen species and are reduced back to methionine by peptide Met(O) reductases. One Met(O) reductase (MsrA) has been known for decades and has recently been shown to regulate lifespan in animals. MsrA, however, is only specific for methionine-S-sulfoxides. The P.I. identified and characterized a second mammalian Met(O) reductase (SelR1) that is specific for methionine-R-sulfoxides. SelR1 is a selenocysteine-contain Jng protein and dietary selenium affects its expression. This raises a possibility that SelR1 may also be involved in delaying the aging process through reduction in levels of Met(O) and that supplementation of diet with selenium may provide means of extending the lifespan of certain segments of the human population. To directly characterize the role of SelR1 in aging, the pathway of Met(O) reduction in mammals will be analyzed with an emphasis on the function of selenoproteinSelR1 and characterization of the lifespan of animals that are either deficient or enriched in SelR1. A combination of biochemical and cell biology approaches and mouse model systems will be used to address the following specific questions (specific aims): 1) What are the properties and reaction mechanisms of SelR1 and its homologs? Three SelR isozymes have been identified in mammals. Wild-type and mutant forms of these proteins will be characterized and their catalytic activities, substrate specificity, metal-binding properties and the ability to complement yeast strains determined; 2) What are the tissue expression patterns, cellular locations and regulation of expression of Met(O) reductases? Hypotheses will be tested that SelR isozymes are located in different cellular compartments and that a single MsrA gene gives rise to two forms of the enzyme. In addition, efficiency of selenocysteine insertion and regulation of SelR1 expression by dietary selenium will be determined; 3) What is the role of SelR in aging? SelR1 knockout mice will generated and the hypothesis tested that these animals are characterized by a reduced lifespan. Transgenic mice overexpressing SelR1 will also be generated to determine whether these animals have increased lifespan.

描述（由申请人提供）：蛋氨酸亚砜 (Met(O)) 还原是一种重要的代谢途径，可提供针对氧化应激的保护并调节蛋白质功能。 Met(O) 在活性氧存在下形成，并被肽 Met(O) 还原酶还原成蛋氨酸。几十年来，一种 Met(O) 还原酶 (MsrA) 已为人所知，最近被证明可以调节动物的寿命。然而，MsrA 仅对蛋氨酸-S-亚砜具有特异性。 P.I.鉴定并表征了第二种哺乳动物 Met(O) 还原酶 (SelR1)，该酶对蛋氨酸-R-亚砜具有特异性。 SelR1 是一种含硒半胱氨酸的蛋白，膳食中的硒会影响其表达。这提出了一种可能性，即 SelR1 也可能通过降低 Met(O) 水平来延缓衰老过程，并且在饮食中补充硒可能提供延长某些人群寿命的方法。为了直接表征 SelR1 在衰老中的作用，我们将分析哺乳动物中 Met(O) 减少的途径，重点关注硒蛋白 SelR1 的功能以及缺乏或富含 SelR1 的动物的寿命特征。生物化学和细胞生物学方法以及小鼠模型系统的结合将用于解决以下具体问题（具体目标）：1）SelR1及其同源物的特性和反应机制是什么？已在哺乳动物中鉴定出三种 SelR 同工酶。这些蛋白质的野生型和突变型将被表征，并确定它们的催化活性、底物特异性、金属结合特性和补充酵母菌株的能力； 2) Met(O) 还原酶的组织表达模式、细胞位置和表达调节是什么？将测试以下假设：SelR 同工酶位于不同的细胞区室中，并且单个 MsrA 基因会产生两种形式的酶。此外，还将确定膳食硒对硒代半胱氨酸插入和 SelR1 表达调节的效率； 3）SelR在衰老中的作用是什么？ SelR1 基因敲除小鼠将会产生，并测试这些动物的特征是寿命缩短的假设。还将产生过度表达 SelR1 的转基因小鼠，以确定这些动物的寿命是否延长。