Store-operated calcium channels in neuropathic pain

描述(申请人提供)：神经性疼痛对执业医生来说是一个临床挑战，对社会是一个巨大的负担。尽管神经病理性疼痛的机制仍未确定，但钙离子通道和受体已与疼痛以及与慢性疼痛状态相关的神经可塑性有关。钙离子通道是一种钙离子选择性很高的阳离子通道，通过内质网钙离子的释放和耗尽而被激活。SOC通道的激活导致细胞内持续的高钙水平，这是许多钙依赖的细胞过程所必需的。在非兴奋性细胞中，SOC通道由新发现的Orai亚基(Orai1/2/3，造孔亚基)和基质相互作用分子(STIM)1和STIM2(内质网钙离子感受器，作为其激活剂)组成。在神经系统中，SOC通道被认为影响神经递质的释放和突触的可塑性。STIM2对缺血诱导的神经细胞内钙离子的积累是必不可少的，但神经元SOC通道的基本特性和SOC通道的分子组成尚不清楚。最近，我们发现SOC通道在脊髓背角神经元中有功能性的表达，并证明SOC通道的激活参与了突触传递。这些观察结果提出了关于SOC通道的功能以及在疼痛信号传递中与这些通道的激活相耦合的信号通路的性质的问题。我们还发现，在备用神经损伤(SNI)后的不同时间点，SOC通道的表达上调。基于这些发现，我们推测SOC通道可能在神经病理性疼痛中发挥作用。为了验证我们的假设，我们将结合膜片钳记录、钙离子成像记录、Taqman实时聚合酶链式反应和行为测试的方法。总体而言，我们的长期目标是确定与慢性疼痛有关的关键分子靶点。本研究的目的是确定SOC通道的基本性质，识别背角神经元中编码SOC通道的分子，并确定SOC通道家族在神经病理性疼痛中的作用。这项研究的预期结果是识别疼痛通路中新的钙信号，以及神经病理性疼痛发生和维持的新机制。

DESCRIPTION (provided by applicant): Neuropathic pain represents a clinical challenge for the practicing physician and is a great burden to society. Although the mechanisms underlying neuropathic pain remain to be established, calcium-permeable ion channels and receptors have been implicated in pain as well as in the neuroplasticity associated with chronic pain states. Store-operated calcium (SOC) channels are highly Ca2+-selective cation channels that are activated by the release and depletion of calcium from the endoplasmic reticulum. Activation of SOC channels leads to sustained high cytosolic Ca2+ levels that are required for many calcium-dependent cellular processes. SOC channels are composed of newly discovered Orai subunits (Orai1/2/3, pore- forming subunits), and stromal interaction molecules (STIM) 1 and STIM2 (the ER Ca2+ sensors, serve as their activators) in non-excitable cells. In the nervous system, SOC channels are known to influence neurotransmitter release and synaptic plasticity. STIM2 is essential for ischemia-induced cytosolic Ca2+ accumulation in neurons, but the basic properties of SOC channels and molecular components underlying SOC channels in neurons are unexplored. Recently, we found that SOC channels are functionally expressed in spinal dorsal horn neurons and demonstrated that activation of SOC channels is involved in synaptic transmission. These observations raise questions as to the function of SOC channels and to the nature of the signaling pathways that are coupled to the activation of these channels in pain signal transmission. We also found that the expression of the SOC channels is upregulated at different time points after spare nerve injury (SNI). Based on these findings, we hypothesize that the SOC channels may play a role in neuronpathic pain. To test our hypothesis, we will combine the methods of patch-clamp recording, calcium imaging recording, Taqman real-time-PCR and behavioral testing. Overall, our long-term goal is to identify key molecular targets involved in chronic pain. The goals of this proposal are to determine basic properties of SOC channels, to identify molecules encoding SOC channels in dorsal horn neurons, and to determine the role of SOC channel family in neuropathic pain. The expected outcome of this research is the identification of new calcium signaling in pain pathway and a new mechanism underlying the development and maintenance of neuropathic pain.