Joint Pain on a Chip: Mechanistic Analysis Therapeutic Targets and an Empirical Strategy for Personalized Pain Management

生活的磨损会使关节受损。结果往往是骨关节炎的疼痛和残疾 （OA）。因为疼痛是OA最令人衰弱的症状，所以它仍然是治疗的主要目标。 通常从非甾体抗炎药（NSAID）发展到弱阿片类药物的干预措施，以及 然后是更强的阿片类药物如果疼痛无法控制，全关节置换手术仍然是唯一可行的长期- 长期治疗选择。然而，相关的风险和成本将必然使手术成为最后的选择 度假村.因此，迫切需要开发安全有效的治疗OA的方法。 相关的疼痛。最近，我们的团队成功开发了一种体外多组件芯片关节（microJoint）， 其中整合了工程化骨软骨复合物、滑膜和脂肪组织。OA样病理学 也在microJoint中成功建模。在这项新的拨款申请中，我们建议引入 感觉神经支配进入微关节。其结果将是一个更“完整”的关节，使动态的相互作用 周围神经系统和关节组织之间的联系我们假设一系列不同的因素 从关节内的不同细胞/组织隔室释放，介导疼痛、超敏反应和超敏反应。 OA的神经支配。此外，我们假设阿片类药物不仅会增加关节退行性变的发生率， 增强疼痛产生介质的释放。在aim 1中，将制备含有神经元的微流体阵列。 开发用于支配当前的微关节（Neu-microJoint）。这个新的生物反应器将是3D打印的， 用于通过嵌入组织室中的多电极阵列对神经活动进行非侵入性评估，以及 高速光学记录。人感觉神经元或诱导多能干细胞（iPSC）衍生的感觉神经元 神经元祖细胞将在新的生物反应器室中培养。在目标2中，我们以前建立的OA模型 将在Neu-microJoint系统中创建。我们将评估伤害感受性神经元的激活和/或致敏作用。 神经传入与电生理学，以及神经突生长。在目标3中，我们将机械地侮辱新- microJoint和评估"疼痛"的出现，以响应关节的长时间机械应力， 目标是创建一个更自然的OA模型。在目标4中，我们将评估临床上使用的药物对 在Neu-microJoint的OA模型上管理OA，作为验证该平台的一种手段， 评价新化合物的疗效和毒性。然后，我们将使用"组学"方法来识别 新的生物标志物和治疗靶点。这种无偏筛选的结果不仅可以揭示损伤特异性 疼痛特征，但建议批准用于人的药物，可以重新用于治疗 OA疼痛。在目标5中，我们将评估阿片类药物在存在和不存在关节炎的情况下对神经活动的影响。 不同刺激引发的损伤，以及所有关节元件的完整性。我们的Neu-microJoint将使 确定与关节损伤相关的疼痛的机制， 目标，治疗干预措施的筛选，以及个性化治疗策略的实施。

Life’s wear and tear can leave joints damaged. All too often, the result is the pain and disability of osteoarthritis (OA). Because pain is the most debilitating symptom of OA, it remains the primary target for therapeutic interventions that typically progress from non-steroidal anti-inflammatory drugs (NSAIDs) to weak opioids, and then to stronger opioids. If pain can’t be controlled, total joint replacement surgery remains the only viable long- term treatment option. However, the associated risks and costs will necessarily keep surgery an option of last resort. Thus, there is a critical need for the development of safe and effective methods for the treatment of OA- associated pain. Recently, our team successfully developed an in vitro multi-component joint on a chip (microJoint), in which engineered osteochondral complexes, synovium and adipose tissues were integrated. OA-like pathology has also been successfully modeled in the microJoint. In this new grant application, we propose to introduce sensory innervation into the microJoint. The result will be a more “complete” joint that enables the dynamic interplay between the peripheral nervous system and joint tissues. We hypothesize that a distinct combination of factors released from different cellular/tissue compartments within the joint mediate pain, hypersensitivity, and hyper- innervation of OA. Furthermore, we hypothesize that opioids not only increase the rate of joint degeneration but potentiate the release of pain producing mediators. In aim 1, a neuron-containing microfluidic ally will be developed to innervate the current microJoint (Neu-microJoint). This new bioreactor will be 3D printed and allow for the non-invasive assessment of neural activity via multi electrode arrays embedded in the tissue chamber, and high-speed optical recording. Human sensory neurons or induced pluripotent stem cell (iPSC)-derived sensory neuron progenitors, will be cultured in the new bioreactor chamber. In aim 2, our previsouly establised OA-model will be created in the Neu-microJoint system. We will assess the activation and/or sensitization of nociceptive afferents with electrophysiology, as well as neurite outgrowth. In aim 3, we will mechanically insult the Neu- microJoint and assess the emergence of “pain” in response to prolonged mechanical stress of the joint with the goal of creating a more natural OA-model. In aim 4, we will assess the impact of drugs used clinically for the management of OA on our OA models in the Neu-microJoint as a means of validating this platform for the assessment of therapeutic efficacy and toxicity of novel compounds. We will then use “omic” approaches to identify new biomarkers and therapeutic targets. Results from this unbiased screen may not only reveal an injury specific pain signature, but suggest medications approved for use in people that could be re-purposed for the treatment of OA pain. In aim 5, we will assess the impact of opioids on neural activity in the presence and absence of joint injury triggered with different stimuli, as well as the integrity of all joint elements. Our Neu-microJoint will enable identification of mechanisms responsible for pain associated with joint injury and therefore novel therapeutic targets, screening of therapeutic interventions, and the implementation of personalized therapeutic strategies.