Tetrahydrobiopterin and pain

四氢生物蝶呤与疼痛

• 批准号: 7912421
• 负责人: CLIFFORD J WOOLF
• 金额: $ 8.19万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2010-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7912421
• 关键词: Absence of pain sensation; Acute Pain; Adult; Adverse effects; Afferent Neurons; Analgesics; Animals; Aromatic Amines; Attenuated; Behavior; Behavioral; Calcium; Calcium Channel; Chronic low back pain; Data; Development; Dopamine; Enzymes; Figs - dietary; GTP Cyclohydrolase; Generations; Grant; Haplotypes; Human; Hypersensitivity; Inflammation; Inflammatory; Knockout Mice; Lesion; Maintenance; Mediator of activation protein; Mixed Function Oxygenases; Modeling; Molecular; Mus; Neurons; Neuropathy; Nitric Oxide; Nitric Oxide Synthase; Norepinephrine; Operative Surgical Procedures; Oxidoreductase; Pain; Partner in relationship; Pathway interactions; Patients; Peripheral; Peripheral Nerves; Peripheral nerve injury; Persistent pain; Phenotype; Production; Protein Isoforms; Proteins; Recycling; Rodent; Rodent Model; Role; Sepiapterin reductase; Serotonin; Single Nucleotide Polymorphism; Societies; Spinal Ganglia; Stimulus; Tamoxifen; Technology; Testing; Time Study; Tissues; Transcript; Transgenic Mice; base; chronic back pain; cofactor; cohort; design; dihydropteridine reductase; economic cost; enzyme activity; experience; inflammatory neuropathic pain; inflammatory pain; inhibitor/antagonist; injured; mutant; nerve injury; novel; overexpression; pain behavior; painful neuropathy; prevent; recombinase; response; selective expression; spinal nerve posterior root; synthetic enzyme; tetrahydrobiopterin

DESCRIPTION (provided by applicant): Transcripts for two tetrahydrobiopterin (BH4) synthetic enzymes, GTP cyclohydrolase 1 (GCH1) and sepiapterin reductase, and a BH4 recycling enzyme quinoid dihydroypteridine reductase, are upregulated in dorsal root (DRG) neurons after peripheral nerve injury. This induction is associated with an increase in BH4 in the DRG. BH4 is an essential cofactor for the aromatic amine hydroxylases that produce 5- hyrdoxytryptamine, norepinephrine and dopamine, and for all nitric oxide synthases. The nerve injury-induced increase in BH4 is prevented by systemic administration of a GCH1 inhibitor, diamino hydroxypyrimidine (DAHP). DAHP has no analgesic effects in naove animals but produces a marked reduction in pain-related behavior in rodents with peripheral nerve lesions and inflammation. Intrathecal BH4 itself produces acute pain hypersensitivity. Using an analysis of single nucleotide polymorphisms we have also identified a haplotype in human GCH1 that is pain protective in patients after surgery for chronic back pain and associated with reduced pain sensitivity in healthy subjects. Based on these data we hypothesize that BH4 contributes to the initiation and maintenance of neuropathic and inflammatory pain. The aim of this proposal is to: 1. Study where and when BH4 induction occurs in the DRG in pain-related rodent models and what kinds of stimuli are responsible, 2. Characterize the behavioral consequences of deletion, inhibition or overexpression of GCH1 selectively in adult primary sensory neurons, and 3. Identify the mechanisms in sensory neurons by which BH4 produces pain. We will study the time course and cellular localization of changes in the expression and activity of BH4 synthetic and recycling enzymes in the DRG in response to tissue inflammation and partial peripheral nerve injury (Aim 1). To elucidate the specific role of BH4 in sensory neurons we will employ mice that selectively overexpress, or have a deletion of GCH1 in adult primary afferents, as well as mice that overexpress the endogenous inhibitor of GCH1, GFRP, using tamoxifen-inducible DRG neuron-specific Cre-recombinase technology (Aim 2). nNOS is upregulated in association with the increase in BH4 and we will test if BH4 produces pain by producing an increase in NO and calcium influx. We will use primary cultures of DRG neurons to explore the direct action of BH4 on these neurons and the downstream effectors responsible. The proposal is designed to explore the molecular mechanisms responsible for pain and identify novel targets for the development of new analgesics. Relevance: Persistent pain is an enormous problem due both to the suffering experienced by patients and the high economic cost to society. Because current therapy is often ineffective or associated with adverse side effects, more efficacious analgesics are required. This grant aims both to understand the mechanisms responsible for pain, and validate a particular enzyme, GCH1, as a target for developing novel analgesics.

描述（由申请人提供）：两种四氢可毒素（BH4）合成酶的转录本，GTP环氧化氢酶1（GCH1）和Sepiapterin还原酶以及BH4再生酶二酰胺二苯胺的再生二氢苯胺还原（均为均具有刺激性），均为均置于疾病中。这种诱导与DRG中BH4的增加有关。 BH4是产生5-羟氧胺，去甲肾上腺素和多巴胺以及所有一氧化氮合酶的芳族胺羟化酶的必需辅助因子。通过全身施用GCH1抑制剂DIAMINO羟基酰亚胺（DAHP），可以预防神经损伤引起的BH4的增加。 DAHP在NAOVE动物中没有镇痛作用，但在周围神经病变和炎症的啮齿动物中，与疼痛相关的行为显着降低。鞘内BH4本身会产生急性疼痛超敏反应。使用单核苷酸多态性的分析，我们还确定了人类GCH1中的单倍型，该单倍型在慢性背痛后手术后具有疼痛保护性，并且与健康受试者的疼痛敏感性降低有关。 基于这些数据，我们假设BH4有助于神经性和炎症性疼痛的启动和维持。该提议的目的是：1。研究与疼痛相关的啮齿动物模型中BH4诱导发生在DRG中的何时何时发生，以及哪种刺激是造成的，2。表征缺失，抑制或过表达GCH1在成人初级感觉神经元中选择性地抑制或过表达GCH1的行为后果，并确定3次痛苦。我们将研究DRG中BH4合成和回收酶的表达和活性变化的时间过程和细胞定位，以响应组织炎症和部分外周神经损伤（AIM 1）。为了阐明BH4在感觉神经元中的具体作用，我们将使用过度表达过度表达或在成年初级传入中删除GCH1的小鼠，以及使用他莫克西法诱导的DRG神经元特异性Cre-Cre-Recombinase（AIM 2）。 NNOS与BH4的增加相关，我们将测试BH4是否通过产生NO和钙涌入的增加而产生疼痛。我们将使用DRG神经元的原发性培养物来探索BH4对这些神经元和负责的下游效应子的直接作用。该提案旨在探索负责疼痛的分子机制，并确定新的镇痛药的发展目标。相关性：由于患者所经历的苦难和社会经济成本的高度，持续性疼痛是一个巨大的问题。由于目前的治疗通常无效或不良副作用有关，因此需要更有效的镇痛药。该赠款的目的是了解负责疼痛的机制，并验证特定的酶GCH1作为发展新型镇痛药的靶标。