The Origin of Tooth Pain: Linking Polymodal TRP channels on Odontoblasts and Pulp Fibroblasts to Sensory Nerves

牙痛的起源：将成牙本质细胞和牙髓成纤维细胞上的多峰 TRP 通道与感觉神经联系起来

• 批准号: 535375124
• 负责人: Professorin Dr. Kerstin Galler, Ph.D.
• 金额: --
• 依托单位: Anästhesiologische Klinik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/535375124?language=en
• 关键词: Origin; Tooth; Pain; Linking; Polymodal

Worldwide, 2.4 billion people suffer from untreated caries and painful tooth hypersensitivity. Bacterial biofilm-related acidic metabolites demineralize enamel and dentin and induce inflammation in the dental pulp. Acidic reflux-induced erosive damage is another wide-spread problem. Tooth ache due to hypersensitivity is a large problem in the dental clinic, because it can be excruciating and common analgesics are ineffective. In the tooth pulp, a dense network of free nerve endings is in intimate contact with immune cells, dentin-forming odontoblasts and fibroblasts. So far, pain from thermal, mechanical, or biochemical cues was believed to arise from a fluid-dynamic induced mechanosensory process where dentinal tubules act as hydraulic link between the physical stimulus and the nerve terminals at the pulp-dentin boundary. However, our previous research delivered experimental evidence for the odontoblast processes as the transduction site for painful cold via TRPC5 channels. Therefore, Odontoblasts act as primary sensory cells and are the origin of tooth pain. Based on these novel findings, this research project follows three main objectives. We assess the specialized localization and differential function of several TRPC channels, including TRPC1, TRPC3 and TRPC4, across odontoblasts, fibroblast and sensory nerves with reporter and knockout mouse models. Then, we establish an optogenetic mouse model to assess the specific function of Odontoblasts in the origin of tooth pain. This model is based on DMP1-Cre, ChR2 and ArchT mice. We use light to manipulate Odontoblasts through the incisor’s lingual surface where the thinner enamel layer is transparent. This model will be combined with extracellular recordings from jaw-nerve preparations and GCaMP-based intravital calcium imaging in trigeminal ganglia. Last but not least, we will develop vital pulp organoids as critical tools to investigate the intricate interplay between nerve endings, odontoblasts and fibroblasts in situ. We will use the tooth pulps from the optogenetic mouse models to generate organoids on intact dentin and innervated by sensory nerves. These organoids will be characterized for their sensory capacity using optogenetic manipulation, patch clamp recordings and confocal calcium imaging, guided by information from our previously established transcriptomic ion channel and GPCR profile from dental primary afferent neurons. The aim is to obtain a concrete ion channel and signaling molecule profile for the mouse and human tooth pulp. In teeth the functionality and sensory properties of the tooth pulp are the result of an intimate interaction of highly specialized cell types and sensory nerves and their understanding is crucial for novel tooth pain treatment strategies and the future advancement of regenerative endodontic therapies aiming at the restoration of sensory and regenerative function of the dental pulp.

全世界有24亿人患有未经治疗的龋齿和疼痛的牙齿过敏。细菌生物膜相关的酸性代谢物使牙釉质和牙本质脱矿，并在牙髓中引起炎症。酸回流引起的腐蚀损害是另一个广泛存在的问题。由于过敏引起的牙齿疼痛是牙科临床上的一个大问题，因为它可能会令人痛苦，而且普通的止痛药是无效的。在牙髓中，一个由游离神经末梢组成的致密网络与免疫细胞、牙本质形成成牙本质细胞和成纤维细胞密切接触。到目前为止，来自热、机械或生化线索的疼痛被认为是由流体动力诱导的机械感觉过程引起的，在这种过程中，牙本质小管在物理刺激和牙髓-牙本质交界处的神经末梢之间起到液压连接作用。然而，我们之前的研究提供了实验证据，证明成牙本质细胞突起是通过TRPC5通道传递疼痛寒冷的部位。因此，成牙本质细胞是主要的感觉细胞，也是牙齿疼痛的根源。基于这些新发现，本研究项目遵循三个主要目标。我们使用报告和基因敲除小鼠模型评估了几种TRPC通道，包括TRPC1、TRPC3和TRPC4，跨成牙本质细胞、成纤维细胞和感觉神经的特殊定位和差异功能。然后，我们建立了一种光遗传小鼠模型，以评估成牙本质细胞在牙齿疼痛起源中的特定功能。该模型建立在DMP1-CRE、ChR2和ARCHT小鼠的基础上。我们使用光通过门牙的舌面操纵牙釉质，在那里较薄的釉质层是透明的。该模型将与颌神经标本的细胞外记录和三叉神经节基于GCaMP的活体钙成像相结合。最后但同样重要的是，我们将开发重要的牙髓有机体作为关键工具来研究神经末梢、成牙本质细胞和原位成纤维细胞之间复杂的相互作用。我们将使用光遗传小鼠模型的牙髓在完整的牙本质上产生有机物，并由感觉神经支配。这些有机化合物将利用光遗传操作、膜片钳记录和共聚焦钙成像来表征它们的感觉能力，并以我们先前建立的转录切割离子通道和牙齿初级传入神经元的GPCR图谱为指导。其目的是获得小鼠和人类牙髓的具体离子通道和信号分子图谱。在牙齿中，牙髓的功能和感觉特性是高度专业化的细胞类型和感觉神经密切相互作用的结果，了解它们对于新的牙痛治疗策略和旨在恢复牙髓感觉和再生功能的再生性牙髓治疗的未来进展至关重要。