Investigating the Role of Heme in Acute and Chronic Sickle Cell Disease Pain

研究血红素在急性和慢性镰状细胞病疼痛中的作用

• 批准号: 10750175
• 负责人: Samuel Joshua Zorn
• 金额: $ 4.98万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10750175
• 关键词: Action Potentials; Acute; Acute Pain; Adolescence; Afferent Neurons; Analgesics; Animals; Behavior; Behavioral; Biological Assay; Blood Circulation; C57BL/6 Mouse; Cells; Chlorides; Chronic; Clinical Research; Complex; Data; Development; Disease; Electrophysiology (science); Erythrocytes; Extravasation; Face; Foundations; Frequencies; Genes; Haptoglobins; Harvest; Heme; Hemin; Hemoglobinopathies; Hemolysis; Hypersensitivity; In Vitro; Individual; Inflammatory; Inherited; Injections; Macrophage; Maintenance; Mechanics; Mediating; Mus; Nerve Fibers; Neurons; Nociception; Nociceptors; Opioid; Organ failure; Pain; Pain management; Pathogenesis; Pathologic; Pathology; Patients; Peripheral; Persistent pain; Punishment; Quality of life; Recurrence; Role; Sensory; Sickle Cell Anemia; Signal Transduction; Sodium Chloride; Spinal Ganglia; Stimulus; Structure of tibial nerve; Symptoms; TLR4 gene; Temperature; Testing; Tissues; Touch sensation; Wild Type Mouse; chronic pain; cytotoxic; experience; experimental study; heme a; improved; in vivo; inflammatory pain; inhibitor; intraperitoneal; novel; novel therapeutics; oxygen transport; pain behavior; pain outcome; pain reduction; painful neuropathy; patch clamp; pre-clinical; pre-clinical research; receptor; release of sequestered calcium ion into cytoplasm; sickling; side effect; spontaneous pain; systemic inflammatory response

Project Summary Individuals with sickle cell disease (SCD) suffer from complex stimulus-evoked and ongoing chronic pain that is mediated in part by the hyperexcitability of their peripheral sensory neurons. However, how the underlying disease pathology leads to ongoing inflammatory and neuropathic pain remains poorly understood. Over the last decade, clinical and pre-clinical research has demonstrated that elevated heme, a key pathological feature of SCD, may contribute to SCD pain. My preliminary data suggest that wildtype (WT) mice receiving intraplantar injections of hemin chloride, the common salt of heme, display acute mechanical hypersensitivity and paw attending behavior. My preliminary data further suggest that reducing the heme burden in SCD mice using intraperitoneally administered haptoglobin, a heme scavenger, reduces mechanical hypersensitivity. Considering these observations, I propose to investigate whether elevated heme is required for the maintenance of pain behavior in Townes SCD. In Aim 1, I hypothesize that elevated heme causes ongoing, non-evoked pain behavior in WT mice by dysregulation of peripheral nociception. I will administer hemin to C57BL/6 mice and conduct facial grimace and conditioned place aversion to determine the contribution of heme to non- evoked pain behavior (Aim 1A). Following the treatment window, I will harvest the dorsal root ganglia (DRGs) sensory neurons from these mice and use patch clamp electrophysiology to determine whether heme-induced pain behavior is driven by peripheral neuron hyperexcitability (Aim 1B). In a parallel study, I will determine whether acute application of hemin to cultured WT DRG neuron induces aberrant neuronal activity and if this dependent on heme's canonical receptor, Toll-like Receptor 4 (TLR4) (Aim 1C). In Aim 2, I hypothesize that chronically elevated heme is required for the maintenance of SCD pain. I will utilize evoked and non-evoked pain behavior assays to determine whether the heme scavenger haptoglobin reduces pain behavior in Townes SCD mice (Aim 2A). Additionally, I will use ex vivo tibial nerve fiber recordings (Aim 2B) and whole-cell patch clamp electrophysiology (Aim 2C) to determine whether the haptoglobin reduces SCD sensory neuron hyperexcitability and mechanical hypersensitivity in these mice. Together these aims will determine if heme drives evoked and non-evoked pain behavior through peripheral sensitization and if heme may be targeted to alleviated SCD chronic pain.

项目摘要 患有镰状细胞病（SCD）的个体患有复杂的刺激诱发和持续的慢性疼痛， 部分由其外周感觉神经元的过度兴奋介导。然而，底层的 疾病病理导致持续的炎性和神经性疼痛仍然知之甚少。在过去 近十年来，临床和临床前研究已经证明，血红素升高， SCD可能导致SCD疼痛。我的初步数据表明，野生型（WT）小鼠接受足底注射， 氯化血红素（血红素的普通盐）的注射显示急性机械超敏性和爪 注意行为。我的初步数据进一步表明，减少血红素负担的SCD小鼠使用 腹膜内施用的触珠蛋白（血红素清除剂）降低机械超敏性。 考虑到这些观察结果，我建议调查是否需要升高血红素来维持 的疼痛行为。在目标1中，我假设血红素升高会引起持续的，非诱发性的 WT小鼠通过外周伤害感受失调的疼痛行为。我会给C57 BL/6注射氯化血红素 小鼠和进行面部鬼脸和条件性位置厌恶，以确定血红素对非 诱发疼痛行为（目的1A）。在治疗窗口之后，我将采集背根神经节（DRG） 感觉神经元，并使用膜片钳电生理学来确定血红素诱导的 疼痛行为是由外周神经元过度兴奋（Aim 1B）驱动的。在一项平行研究中，我将确定 对培养的WT DRG神经元急性施用氯化血红素是否诱导异常神经元活性，以及如果这 依赖于血红素的典型受体Toll样受体4（TLR 4）（Aim 1C）。在目标2中，我假设 慢性升高的血红素是维持SCD疼痛所必需的。我会利用诱发和非诱发 疼痛行为测定以确定血红素清除剂触珠蛋白是否减少Townes的疼痛行为 SCD小鼠（Aim 2A）。此外，我将使用离体胫神经纤维记录（Aim 2B）和全细胞贴片 钳夹电生理学（Aim 2C）以确定触珠蛋白是否减少SCD感觉神经元 过度兴奋和机械超敏反应。这些目标将共同决定血红素 通过外周敏化驱动诱发和非诱发疼痛行为，如果血红素可以靶向 缓解SCD慢性疼痛。