Toxicological Aspects of Hemoprotein Regulation

血红素蛋白调节的毒理学方面

• 批准号: 6782483
• 负责人: YOICHI OSAWA
• 金额: $ 36.84万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6782483
• 关键词: enzyme activity; enzyme induction /repression; enzyme inhibitors; hemoprotein metabolism; laboratory rat; nitric oxide synthase; protein degradation; tobacco; toxicology

DESCRIPTION (provided by applicant): The objective of the proposed research is to elucidate the mechanisms of inactivation, degradation, and turnover of neuronal nitric oxide synthase (nNOS), a cytochrome P450-like hemoprotein, caused by exposure to xenobiotics, including drugs and environmental toxicants. The central hypothesis is that such effects diminish the ability to form NO, an important bioregulatory molecule involved in many physiological functions, and cause some forms of chemically induced toxicities. It was recently shown that guanabenz (WytensinTM), an antihypertensive agent, inactivates penile nNOS in vitro in a metabolism dependent manner and causes a loss of nNOS protein and activity in vivo. Similarly, cigarette smoke contains compounds that lead to metabolism-based inactivation and loss of penile nNOS in vivo. These findings may be important as NO plays a key role in penile erection and antihypertensive agents as well as cigarette smoking are known to cause impotence. Several metabolism-based in activators, including guanabenz, were found to cause the enhanced proteolytic degradation of nNOS that, in part, causes the loss of nNOS protein in vivo. This degradation was found to involve hsp9o-based chaperones, ubiquitination, and proteasomal degradation. Thus, the aims of the current proposal are to understand how nNOS is inactivated and covalently altered by xenobiotics and how the steady state levels of nNOS are subsequently affected. This will involve the study of not only the degradation process but also the opposing forces of repair or assembly of nNOS. We will utilize modern chemical and biological techniques in vitro, cellular, and in vivo models to address these aims. The specific aims are: (1) To determine the molecular mechanism of nNOS inactivation caused by metabolism-based in activators, (2) To characterize the structural determinants that render nNOS susceptible to ubiquitination and proteasomal degradation, (3) To characterize the processes responsible for activation or maintenance of nNOS function, (4) To characterize the effect of tobacco smoke constituents on nNOS with the use of knowledge gained in Aims 1-3. These studies should lead to a better understanding of how drugs inactivate and regulate nNOS and thereby lead to the design of safer drugs without undesired toxicological side effects, such as impotence. Conversely, the same knowledge could be used to design safer and more effective inhibitors of NOS for pharmacological use in a variety of neurological diseases.

描述（由申请人提供）：拟议研究的目标是 阐明失活、降解和更新的机制 神经元一氧化氮合酶 (nNOS)，一种细胞色素 P450 样血红蛋白， 由接触外源性物质（包括药物和环境毒物）引起。 核心假设是，这种效应会降低形成 NO 的能力，NO 是一种 参与许多生理功能的重要生物调节分子， 引起某些形式的化学毒性。最近显示， 胍那苯 (WytensinTM) 是一种抗高血压药，可灭活阴茎中的 nNOS 以代谢依赖性方式体外并导致 nNOS 蛋白损失 体内活性。同样，香烟烟雾中含有导致 体内基于代谢的阴茎 nNOS 失活和损失。这些发现 可能很重要，因为一氧化氮在阴茎勃起和抗高血压中起着关键作用 众所周知，药物和吸烟都会导致阳痿。一些 基于代谢的激活剂，包括胍，被发现会导致 nNOS 的蛋白水解降解增强，部分导致 nNOS 损失 体内的蛋白质。发现这种降解涉及基于 hsp9o 的伴侣， 泛素化和蛋白酶体降解。因此，当前的目标 提议是了解 nNOS 如何被灭活和共价改变 异生素以及 nNOS 的稳态水平随后如何受到影响。 这不仅涉及降解过程的研究，还涉及 nNOS 修复或组装的相反力量。我们将利用现代化学 和生物技术体外、细胞和体内模型来解决 这些目标。具体目标是：（1）确定其分子机制。 由基于代谢的激活剂引起的 nNOS 失活，(2) 表征 使 nNOS 易于泛素化的结构决定因素 蛋白酶体降解，(3) 表征负责的过程 nNOS 功能的激活或维持，(4) 表征 利用 Aims 中获得的知识对 nNOS 上的烟草烟雾成分进行分析 1-3.这些研究应该有助于更好地了解药物如何 灭活和调节 nNOS，从而设计出更安全的药物 没有不良的毒理学副作用，例如阳痿。反过来， 同样的知识可以用来设计更安全、更有效的抑制剂 NOS 在多种神经系统疾病中的药理学用途。

项目成果

Alteration of the heme prosthetic group of neuronal nitric-oxide synthase during inactivation by N(G)-amino-L-arginine in vitro and in vivo.

• DOI: 10.1124/mol.62.1.110
• 发表时间: 2002-07
• 期刊: Molecular pharmacology
• 影响因子: 3.6
• 作者: J. Vuletich;E. Lowe;S. Jianmongkol;Y. Kamada;U. Kent;Andrew T. Bender;Damon R. Demady;P. Hollenberg;Y. Osawa

Metabolism of aminoguanidine, diaminoguanidine, and NG-amino-L-arginine by neuronal NO-synthase and covalent alteration of the heme prosthetic group.

• DOI: 10.1021/tx050263c
• 发表时间: 2005-12
• 期刊: Chemical research in toxicology
• 影响因子: 4.1
• 作者: Anthony J. Lee;Kathleen R. Noon;S. Jianmongkol;Miranda Lau;Gary J. Jenkins;Y. Osawa

Nitric oxide synthase plays a signaling role in TCR-triggered apoptotic death.

• DOI: 10.4049/jimmunol.161.12.6526
• 发表时间: 1998-12
• 期刊: Journal of immunology
• 影响因子: 4.4
• 作者: Mark S. Williams-Mark S.-Williams-2205705637;S. Noguchi;P. Henkart;Yoichi Osawa

Metabolism-based inactivation of penile nitric oxide synthase activity by guanabenz.

• 发表时间: 1998-05
• 期刊: Drug metabolism and disposition: the biological fate of chemicals
• 作者: M. Nakatsuka;K. Nakatsuka;Y. Osawa

Naturally occurring neuronal NO-synthase inactivators found in Nicotiana tabacum (Solanaceae) and other plants.

在烟草（茄科）和其他植物中发现的天然神经元一氧化氮合酶灭活剂。

• DOI: 10.1016/j.phymed.2006.09.004
• 发表时间: 2007
• 期刊: Phytomedicine : international journal of phytotherapy and phytopharmacology
• 作者: Lowe,EzraR;Everett,AndrewC;Lau,Miranda;Dunbar,AnwarY;Michener,David;Osawa,Yoichi
• 通讯作者: Osawa,Yoichi