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

项目总结： 流行病学研究表明，颞下颌关节紊乱病(TMD)疼痛和偏头痛是 紧密联系在一起。具体地说，偏头痛似乎在患有肌源性TMD的女性中更为普遍。 然而，TMD疼痛的分子机制及其与偏头痛的共病以及性别 分歧仍然鲜为人知。我们的长期目标是确定开发一部小说的潜在目标 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 通过联合咬肌肌腱结扎术(MMTL)研究TMD疼痛及其与偏头痛的共病 通过全身注射硝酸甘油(NTG)诱导的偏头痛样疼痛来产生肌源性TMD，本工作 是最近出版的。利用rna测序和qpr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。我们观察了 强啡肽首次阻断雌性小鼠三叉神经脊束核尾侧核(Sp5C) 显著抑制肌源性TMD疼痛和减轻TMD增强的偏头痛样疼痛，Sp5C 注射强啡肽可使非致敏剂量的NTG在女性患者中产生持续性偏头痛样疼痛 老鼠，但不是雄鼠。我们进一步发现Sp5C拮抗缓激肽受体，而不是kappa阿片类物质 受体，可抑制雌性小鼠的这种重叠疼痛。此外，缓激肽受体B2(BKRB2)，但不是 BKRB1在Sp5C中表达，MMTL联合NTG处理降低了BKRB2与神经元的结合 一氧化氮合酶(NNOS)和增加Sp5C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，Sp5C强啡肽可以扮演一只雌性- 通过非阿片受体机制在TMD疼痛及其与偏头痛的共病中的特殊作用。在这 项目，我们将确定三叉神经强啡肽参与TMD和TMD的中枢机制 偏头痛重叠疼痛状态。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BKRB2，然后抑制其与nNOS的结合而导致雌性小鼠的共病 增加Sp5C中一氧化氮的产生，从而促进TMD和偏头痛重叠疼痛。为了测试这一点 中心假设，我们将使用多学科方法来表征女性特有的三叉神经作用 强啡肽在TMD和偏头痛重叠疼痛中的作用(目标1)，确定强啡肽在TMD和偏头痛中的受体机制 三叉神经痛调节(目标2)，并确定三叉神经强啡肽信号的下游通路 伤害性感受系统(目标3)。总而言之，我们希望揭示三叉神经的中枢机制 强啡肽对女性的TMD和偏头痛共病有明确的贡献。拟议的研究是 它具有重要意义，因为它将促进我们对TMD疼痛及其共病的理解。建议进行的研究包括 创新，因为这些研究将确定以前未被认识的女性特有的强啡肽在 三叉神经重叠疼痛状况。

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.