Sickle cell disease gut dysbiosis effects on CNS pain processing

研究综述 疼痛是镰状细胞病（SCD）患者最常见的并发症。SCD患者患有 与血管闭塞性发作相关的剧烈急性疼痛和经常没有血管闭塞性发作的慢性疼痛。 明显的病态阿片类药物是用于治疗SCD疼痛的主要疗法，尽管它们具有负面的长期副作用 影响、缺乏疗效和相关治疗障碍。为了开发更好的SCD疼痛疗法， 需要对SCD疼痛的神经生物学基础有更多的机械理解。很少有研究 描述了大脑在SCD疼痛中的作用，尽管患者报告了中枢致敏和情感性共同作用， 发病率，这两者都与SCD疼痛强度和频率增加相关。中央核 杏仁核（CeA）是由急性疼痛，慢性疼痛和情感障碍激活的边缘脑区域; 在转基因SCD小鼠中注意到增加的CeA活性。我们的长期目标是确定SCD相关因素 增加CeA神经元活性和疼痛样行为，以开发新的SCD疼痛疗法。这 该提案将研究肠道微生物组如何影响SCD中的CeA活性。来自无菌小鼠的数据显示， 完整的肠道微生物组对正常的杏仁核功能至关重要。患者和小鼠的肠道微生物组 SCD模型与健康对照不同（即表现出生态失调）。抗或益生菌操纵 肠道微生物组改变SCD小鼠的疼痛样行为和CeA信号传导。具体目标是 该提案将研究这些变化背后的神经机制。在具体目标1中，我们将使用纤维 在以下条件下使用光度法测量背景和疼痛诱发的CeA活性：（A）假- 用SCD粪便材料接种的无菌小鼠，（B）接受纵向青霉素治疗的SCD小鼠， 和（C）进行迷走神经切断术的SCD小鼠。这些实验将使我们能够确定 以及SCD肠道生态失调影响CeA活性的机制。在具体目标2中，我们将直接 操纵选择的CeA神经元群体，以确定每个神经元如何参与生态失调相关的疼痛。我们 将首先使用光遗传学来抑制SCD感染的假无菌小鼠中选择的CeA神经元的活性 排泄物然后，我们将确定CeA中的5 HT 2A受体活性是否有助于SCD生态失调相关 痛苦最后，我们将确定新的神经元信号传导途径，通过该途径SCD肠道微生物组可以 让人痛苦这些实验将成为我独立研究实验室的基础， 研究伤害感受的解剖学和化学基础，以开发个性化的治疗方法， 患有SCD和其他慢性疼痛障碍的个体。

Research Summary Pain is the most common complication for patients with sickle cell disease (SCD). Patients with SCD suffer from intense acute pain that is associated with vaso-occlusive episodes and chronic pain which frequently has no obvious pathology. Opioids are the main therapy used to treat SCD pain, despite their negative long-term side effects, lack of efficacy, and associated treatment barriers. In order to develop better therapies for SCD pain, a more mechanistic understanding of the neurobiological basis of SCD pain is needed. Very few studies have characterized the role of the brain in SCD pain, despite patient reports of central sensitization and affective co- morbidities, both of which are correlated with increased SCD pain intensity and frequency. The central nucleus of the amygdala (CeA) is a limbic brain region activated by acute pain, chronic pain, and affective disturbances; increased CeA activity is noted in transgenic SCD mice. Our long-term goal is to identify SCD-related factors that increase CeA neuronal activity and pain-like behaviors in order to develop novel SCD pain therapies. This proposal will examine how the gut microbiome influences CeA activity in SCD. Data from germ-free mice show that an intact gut microbiome is critical for normal amygdala function. The gut microbiome of patients and mouse models with SCD differs from that of healthy controls (i.e. exhibit dysbiosis). Anti- or probiotic manipulation of the gut microbiome changes pain-like behaviors and CeA signaling in SCD mice. The specific aims of this proposal will examine the neuronal mechanisms underlying these changes. In Specific Aim 1, we will use fiber photometry to measure background and pain-evoked CeA activity in the following conditions: (A) pseudo- germfree mice recolonized with SCD fecal material, (B) SCD mice that received longitudinal penicillin treatment, and (C) SCD mice that underwent vagotomy surgery. These experiments will allow us to determine the extent and mechanism through which SCD gut dysbiosis affects CeA activity. In Specific Aim 2, we will directly manipulate select populations of CeA neurons to determine how each is involved in dysbiosis-related pain. We will first use optogenetics to inhibit activity of select CeA neurons in pseudo-germfree mice recolonized with SCD fecal material. We will then determine if 5HT2A receptor activity in the CeA contributes to SCD dysbiosis-related pain. Finally, we will identify novel neuronal signaling pathways through which the SCD gut microbiome could be driving pain. These experiments will be the foundation for my independent research laboratory which will study the anatomical and chemical basis of nociception in order to develop personalized therapeutics for individuals suffering from SCD and other chronic pain disorders.