Functional peripheral and central vagal neural circuits of interoception inhibiting pain

颞下颌关节紊乱病是指引起下颌、咀嚼肌和相关头部疼痛和功能障碍的疾病 和颈部肌肉骨骼结构。美国成年人的患病率为24%，超过1500万人 患者受到严重疼痛和下颌运动受限的影响，导致生活质量降低和高 经济负担。尽管有这些成本，生物标志物或生物标志物签名的确切机制 在TMD患者中发生的这种情况尚不清楚，也不清楚在原发性 感觉神经元或周围TMJ区域介导慢性、持续性颌关节和肌肉疼痛的转变。 因此，这些患者的治疗选择受到严重限制。在本提案中，我们将执行单细胞 颞下颌关节组织RNA序列分析和鸟枪脂质体分析 TMD疼痛的传导、传递和调节。我们的目标是描绘生物标志物， 生物标志物签名，并确定非阿片类药物治疗的新靶点，以改善对 TMD疼痛患者。在我们对TMD疼痛的生物标志物和/或生物标志物特征的分析中，我们将考虑 颞下颌关节和口面区域独特的神经生物学。首先，不同的口面组织和区域，包括 颞下颌关节，可能导致不同的TMD疼痛。由于椎间盘后组织高度受外周神经支配， 与其他区域相比，神经和血管高度发达，这种错位增加了直接的机械损伤。 在关节功能期间对椎间盘后组织的刺激，这导致炎性变化， 病理学此外，口面部区域，特别是咬肌，其连接下颌骨和 颧骨也可能因TMJ损伤而受损和/或发炎。咬肌用于咀嚼， 咬紧牙关由于磨牙和咬紧牙关而导致的肌肉过度使用会导致肌肉紧张， 发炎疼痛因此，椎间盘后组织和咬肌可能是非阿片类药物的理想靶点。 疼痛治疗的治疗方法。第二，性别是一个重要的生物学变量。由于TMD疼痛非常普遍， 在女性中，我们将主要关注这一人群以及性激素调节的作用， 受体在疼痛调节中的作用我们推测，损伤诱导颞下颌关节神经生物学的实质性变化， 尤其是年轻女性的分子特征第三，除了定位于大脑皮层的伤害性感觉传入外， 三叉神经节（TG），颞下颌关节也受迷走神经传入神经支配。我们的初步数据表明颞下颌关节迷走神经 传入神经能抑制TMJ损伤引起的痛觉过敏，提示它们能调节TMD疼痛的严重程度。 因此，我们将进行遗传和脂质组学检测的迷走神经节投射到颞下颌关节。在目标1中，我们 描述周围TMJ组织中TMD疼痛的生物标志物和/或生物标志物特征，以及TG和迷走神经 神经节（VG）神经元投射到TMJ（RNA测序和脂质组学）。生物标志物和/或生物标志物 来自TMD疼痛的特征将通过使用TMJ组织的RNA测序和脂质组学测定来筛选， 口面组织我们将通过对单个脂质的识别和定量来确定脂质的景观 物种（可能有数千种）和多磷酸肌醇类，并将确定改变代谢途径， 应用基于多维质谱的TMJ传入纤维和损伤及对照小鼠的TG和VG 鸟枪脂质组学（MDMS-SL）。在目标2中，我们将确定非阿片类药物治疗TMJ炎症的靶点， 人类的口面区域我们的RNA测序和脂质组学分析有望提供遗传和 脂质组学信息和对健康和发炎的TMJ中TMJ和口面组织的动态的洞察 从老鼠和人类身上。我们希望这些发现将有助于确定新的靶点， TMD疼痛的非阿片类药物治疗。

TMDs are conditions that cause pain and dysfunction in the jaw, the masticatory muscles, and associated head and neck musculoskeletal structures. The prevalence among U.S. adults is 24%, and more than 15 million patients are affected by severe pain and limited mandibular motion, resulting in reduced quality of life and a high economic burden. Despite these costs, the exact mechanisms by which biomarkers or biomarker signatures occur in TMD patients are not well known, nor is it clear what specific molecules at the level of the primary sensory neuron or peripheral TMJ region mediate the transition to chronic, persistent jaw joint and muscle pain. As a result, treatment options for these patients are severely limited. In this proposal, we will perform single cell and tissue RNA sequence analysis and shotgun lipidomic analysis of temporomandibular joint (TMJ) relevant to the transduction, transmission, and regulation of TMD pain. Our objective is to delineate biomarkers and biomarker signatures and to identify novel targets of non-opioid therapeutics to improve the management of patients with TMD pain. In our analysis of biomarkers and/biomarker signatures in TMD pain, we will consider the unique neurobiology of TMJ and orofacial regions. First, different orofacial tissues and regions, including TMJ, likely contribute differentially to TMD pain. Since the retrodiscal tissues are highly innervated by peripheral nerves and are highly vascularized compared to other regions, such malpositioning increases direct mechanical irritation of the retrodiscal tissues during joint functions, which leads to inflammatory changes and further pathologies. In addition, the orofacial region, especially masseter muscle, which connects the mandible to the cheekbone may also be damaged and/or inflamed by TMJ injury. The masseter muscle is used for chewing and jaw clenching. Muscle overuse from tooth-grinding and jaw-clenching cause the muscle to become tense, inflamed, and painful. Thus, retrodiscal tissues and masseter muscle might provide ideal targets for non-opioid therapeutics for pain therapy. Second, sex is an important biological variable. Since TMD pain is highly prevalent in females, we will have a primary focus on this population and on the role of sex hormone regulation and receptors in pain regulation. We presume that injury induces substantial changes in TMJ neurobiology and molecular signature particularly in young females. Third, in addition to nociceptive sensory afferents localized in trigeminal ganglia (TG), TMJ is also innervated by vagal afferents. Our preliminary data suggest that TMJ vagal afferents can inhibit hyperalgesia induced by TMJ injury suggesting they can modulate severity of TMD pain. Therefore, we will undertake genetic and lipidomic assays of vagal ganglia projecting to TMJ. In Aim 1, we will delineate biomarkers and/or biomarker signatures of TMD pain in peripheral TMJ tissues and TG and vagal ganglia (VG) neurons projecting to TMJ (RNA sequencing and lipidomics) in mice. Biomarkers and/or biomarker signatures from TMD pain will be screened by RNA sequencing and lipidomics assays using TMJ tissue and orofacial tissue. We will determine the landscape of lipids by identification and quantification of individual lipid species (potentially thousands) and polyphosphoinositide classes and will identify altered metabolic pathways in TMJ afferents and TG and VG from injured and control mice using multi-dimensional mass spectrometry-based shotgun lipidomics (MDMS-SL). In Aim 2, we will Identify targets for non-opioid therapeutics in inflamed TMJ and orofacial regions in humans. Our RNA sequencing and lipidomics analysis promise to provide genetic and lipidomic information and insight into the dynamics of the TMJ and orofacial tissue in healthy and inflamed TMJ from mice and humans. We expect the findings will facilitate identification of novel targets for development of non-opioid therapeutics for TMD pain.