The Role of the OLAM System in Burn Pain

描述(由申请人提供)：据估计，美国每年发生200万例烧伤，其中约15%需要住院治疗。烧伤患者的主要主诉是强烈的、往往是毁灭性的自发性疼痛，并伴有持续的机械和热痛过敏和痛觉过敏。因此，迫切需要进行基础研究，以了解烧伤疼痛的机制，并确定潜在的治疗方法。瞬时受体电位(Trp)配基门控离子通道家族中的一个重要成员是Trp香草酸亚家族1(TRPV1)离子通道，它表达于主要的伤害性神经元亚群上。TRPV1转导作用于周围组织的各种有害的物理和化学刺激。TRPV1离子通道在检测包括伤害性热在内的许多刺激中起着关键作用，并有助于热痛觉过敏。TRPV1受体在介导烧伤后疼痛中的作用尚不完全清楚。因此，对TRPV1促进烧伤后疼痛的机制的进一步研究解决了知识上的一个重要差距，并可能为治疗烧伤后患者提供创新的方法。我们实验室先前发表的数据揭示了一类新型的内源性TRPV1激动剂--氧化亚油酸代谢物(OLAM)，它在热和炎症组织损伤时释放。最近的初步研究证实，细胞色素P450(CYP)酶系统在亚油酸诱导的培养神经元释放OLAM过程中起到调节作用。基于这些研究，以及作为初步数据提出的其他结果，我们认为热损伤导致CYP系统的持续激活，导致亚油酸氧化代谢产物(OLAMS)的产生和TRPV1的激活。以下特定目标将验证这一创新假说：特定目标1确定热损伤是否通过CYP介导的OLAM释放激活辣椒素敏感伤害性感受器。特异性目的1使用体外细胞方法评估周围烧伤后OLAM系统激活TRPV1的假说。AIM 1提供了学习膜片钳电生理学的机会，这一方法为我未来的神经生物学家职业生涯提供了宝贵的工具。特定目的2鉴定热损伤后感觉神经元中上调的CYP酶。特定目标2将鉴定和表征烧伤后感觉神经元中上调的CYP亚型。这个目标提供了一个学习qRT-PCR和细胞内免疫中和的绝佳机会，这两项技术将加强我未来作为神经生物学家的职业生涯。

DESCRIPTION (provided by applicant): It has been estimated that 2 million burn injuries occur yearly in the US, with ~15% of these injuries requiring hospitalization. The primary complaint of burn victims is an intense, often devastating spontaneous pain, with persistence of both mechanical and thermal allodynia and hyperalgesia. Thus, there is a compelling need for fundamental research aimed at understanding mechanisms of burn pain and in identifying potentially novel therapeutic approaches for treating it. A prominent member of the family of transient receptor potential (TRP) ligand-gated ion channels is the TRP vanilloid subfamily 1 (TRPV1) ion channel, and is expressed on a major subpopulation of nociceptive neurons. TRPV1 transduces various noxious physical and chemical stimuli applied to peripheral tissues. The TRPV1 ion channel plays a critical role in detecting many of these stimuli, including noxious heat, and contributes to heat hyperalgesia. The role of the TRPV1 receptor in mediating pain post burn injury is incompletely understood. Thus, further research on the mechanisms by which TRPV1 contributes to post-burn pain addresses an important gap in knowledge and may offer innovative approaches for treating the post-burn patient. Our lab has previously published data revealing a novel class of endogenous TRPV1 agonists, the oxidized linoleic acid metabolites (OLAMs), which are released upon thermal and inflammatory tissue injury. More recent preliminary studies have identified the cytochrome P450 (CYP) enzyme system in mediating the release of OLAMs from cultured neurons exposed to linoleic acid. Based upon these studies, as well as additional results presented as Preliminary Data, we propose that thermal injury leads to persistent activation of a CYP system leading to generation of oxidative metabolites of linoleic acid (OLAMs) and activation of TRPV1. The following specific aims will test this innovative hypothesis: Specific Aim 1 Determine whether thermal injury activates capsaicin-sensitive nociceptors via CYP mediated release of OLAMs. Specific Aim 1 uses in vitro cellular methods to evaluate the hypothesis that the OLAM system activates TRPV1 after peripheral burn injury. Aim 1 affords the opportunity to learn patch clamp electrophysiology, a method providing a valuable tool in my future career as a neurobiologist. Specific Aim 2 Identify CYP enzymes that is up-regulated in sensory neurons after thermal injury. Specific Aim 2 will identify and characterize CYP isoforms that are up-regulated in sensory neurons after burn injury. This Aim provides an excellent opportunity to learn both qRT-PCR as well as intracellular immunoneutralization, two techniques which will strengthen my future career as a neurobiologist.