Female-specific role of trigeminal dynorphin in temporomandibular disorder and its comorbidity

项目摘要： 流行病学研究表明，颞下颌关节紊乱病（TMD）疼痛和偏头痛是 密切相关。具体来说，偏头痛似乎更普遍的妇女与肌源性TMD。 然而，TMD疼痛的分子机制及其与偏头痛的共病以及它们的性别 对差异的了解仍然很少。我们的长期目标是确定潜在的目标， 治疗TMD和偏头痛重叠疼痛。在我们的初步研究中，我们开发了一种动物模型， 结合咬肌肌腱结扎术（MMTL）研究TMD疼痛及其与偏头痛的共病性。 通过全身注射硝酸甘油（NTG）诱导的偏头痛样疼痛产生肌源性TMD，这项工作 最近出版了。使用RNA测序，然后进行qPCR确认，我们鉴定了三叉神经 强啡肽作为这种重叠疼痛状况的潜在女性特异性治疗靶点。我们观察到， 首次阻断雌性小鼠三叉神经脊束核尾侧（Sp 5C）强啡肽 显著抑制肌源性TMD疼痛，并减少TMD增强的偏头痛样疼痛， 注射强啡肽可使非致敏剂量的NTG在女性中产生持续性偏头痛样疼痛 老鼠，但不是雄性老鼠。我们进一步发现Sp 5C拮抗缓激肽受体，而不是κ阿片样物质 受体，抑制雌性小鼠的这种重叠疼痛。此外，缓激肽受体B2（BKRB 2），而不是 BKRB 1在Sp 5C中表达，并且MMTL加NTG处理降低了BKRB 2与神经元的结合。 一氧化氮合酶（nNOS），并增加Sp 5C中的NOS活性，这将增加一氧化氮的产生 然后促进偏头痛的发展。这些结果表明，Sp 5C强啡肽可以发挥女性- 通过非阿片受体机制在TMD疼痛及其与偏头痛共病中的特定作用。在这 项目，我们将确定三叉神经强啡肽有助于TMD的中枢机制， 偏头痛重叠疼痛状况。我们的假设是，三叉神经强啡肽增强TMD和偏头痛 通过激活缓激肽受体BKRB 2，然后抑制其与nNOS的结合， 增加Sp 5C中一氧化氮的产生，从而促进TMD和偏头痛重叠疼痛。为了验证这一 中心假设，我们将使用多学科的方法来表征女性特有的三叉神经的作用， 强啡肽在TMD和偏头痛重叠疼痛中的作用（目的1），确定强啡肽在TMD和偏头痛重叠疼痛中的受体机制。 三叉神经痛调节（Aim 2），并定义三叉神经痛中强啡肽信号传导的下游通路。 伤害感受系统（Aim 3）。总的来说，我们希望揭示三叉神经的中枢机制， 强啡肽特别有助于女性的TMD和偏头痛合并症。拟议的研究是 这将有助于我们进一步了解TMD疼痛及其并发症。拟议的研究是 创新，因为这些研究将确定强啡肽以前未被认识到的女性特异性作用， 三叉神经重叠疼痛状态。

Project Summary: Epidemiological studies have shown that temporomandibular disorders (TMDs) pain and migraine headache are closely associated. Specifically, migraine headache appears to be more prevalent in women with myogenic TMD. However, the molecular mechanisms for TMD pain and its comorbidity with migraine as well as their sex differences remain poorly understood. Our long-term goal is to identify potential targets for developing a novel therapy for TMD and migraine overlapping pain. In our preliminary studies, we have developed an animal model to study TMD pain and its comorbidity with migraine by combining masseter muscle tendon ligation (MMTL)- produced myogenic TMD with systemic injection of nitroglycerin (NTG)-induced migraine-like pain, and this work has been published recently. Using RNA sequencing followed by qPCR confirmation, we identified trigeminal dynorphin as a potential female-specific therapeutic target for this overlapping pain condition. We observed for the first time that blockade of dynorphin in the spinal trigeminal nucleus caudalis (Sp5C) of female mice significantly inhibits myogenic TMD pain and diminishes TMD-enhanced migraine-like pain, and that Sp5C injection of dynorphin enables a non-sensitizing dose of NTG to produce persistent migraine-like pain in female mice, but not male mice. We further found that Sp5C antagonism of bradykinin receptor, but not kappa opioid receptor, inhibits such overlapping pain in female mice. Moreover, bradykinin receptor B2 (BKRB2), but not BKRB1, is expressed in the Sp5C, and MMTL plus NTG treatment decreases the binding of BKRB2 with neuronal nitric oxide synthase (nNOS) and increases NOS activity in the Sp5C, which will increase nitric oxide production and then promote migraine pain development. These results suggest that Sp5C dynorphin could play a female- specific role in TMD pain and its comorbidity with migraine through a non-opioid receptor mechanism. In this project, we will determine the central mechanisms by which trigeminal dynorphin contributes to TMD and migraine overlapping pain condition. Our hypothesis is that trigeminal dynorphin enhances TMD and migraine comorbidity in female mice by activating bradykinin receptor BKRB2 and then inhibiting its binding with nNOS to increase nitric oxide production in the Sp5C, thereby promoting TMD and migraine overlapping pain. To test this central hypothesis, we will use multidisciplinary approaches to characterize female-specific role of trigeminal dynorphin in TMD and migraine overlapping pain (Aim 1), determine the receptor mechanism for dynorphin in trigeminal pain regulation (Aim 2), and define the downstream pathway of dynorphin signaling in trigeminal nociceptive system (Aim 3). Collectively, we expect to reveal the central mechanisms by which trigeminal dynorphin specifically contributes to TMD and migraine comorbidity in females. The proposed research is significant since it will advance our understanding of TMD pain and its comorbidity. The proposed studies are innovative since these studies will identify a previously unrecognized female-specific role for dynorphin in trigeminal overlapping pain condition.