Genetics and phenomics of widespread neuropathic trigeminal pain in the mouse

描述（由申请人提供）：为了验证假设，即。鉴于三叉神经痛是一种复杂的遗传特征，我们最近通过单侧切断眶下神经（IONX）建立了一种新的小鼠颅面神经痛（CNP）模型。我们发现轻触引起的疼痛（即异常性疼痛）和有害刺激（即痛觉过敏）引起的疼痛增加出现在耳朵、爪子和尾巴上，并且取决于所研究菌株的性别和遗传背景。该模型是研究CNP遗传机制的强大平台，CNP常见于人类，尤其是女性。我们的具体目标是确定导致CNP易感性差异的候选遗传因素。由于其中一些可能编码电压和配体离子通道基因，在AIM-1中，我们将在20个近交小鼠品系中鉴定235个此类基因的snp并重建其单倍型。AIM-2：对这些小鼠进行CNP后离子x表型分析，并对其单倍型图谱进行计算遗传分析，我们将确定控制CNP的遗传因素。对23个AXB-BXA重组近交系小鼠株进行表型分析，然后对其已知遗传图谱进行连锁分析，将使我们能够确定CNP的QTL区间。利用表达阵列，我们将鉴定三叉神经尾侧亚核（Vc）中不同CNP水平的菌株的差异表达基因。这3个图谱的叠加应该能够鉴定出CNP的候选基因。这不是本研究的一部分，我们将在三叉神经痛（和其他）神经性疼痛患者队列中对这些基因进行基因分型。AIM-3：在AIM 2中分型的43个菌株中，CNP水平将使我们能够提供最高对比菌株作为研究神经损伤后中枢神经系统可塑性机制的标准化新平台，测试新型镇痛药，并为未来的深入研究提供新的假设。我们将对这些菌株进行表型分析，以确定CNP与神经损伤后中枢可塑性相关的特征：(i) Vc中疼痛抑制神经元的兴奋毒性破坏，（ii）癫痫发作倾向作为CNS抑制的探针，（iii）星形胶质细胞和小胶质细胞的变化，以及（iv） FOS标记以研究Vc和腰骶神经池的躯体图的可塑性，这些神经元池对腹膜外痛觉过敏部位的急性有害刺激做出反应。这些遗传和表型研究被认为是研究三叉神经痛综合征的一个新的和强大的模型。确定影响三叉神经痛综合征的遗传因素可以提供新的治疗靶点。

DESCRIPTION (provided by applicant): To test the hypo,thasis.that trigeminal pain spdrom,es are complex genetic traits, we recently produced a new mouse model of kraniofacial neuropathic pain (CNP), by unilaterally cutting the infraorbital nerve (IONX). We found thaf pain to light touch (i.e., allodynia) and increased pain to noxious stimuli (i.e., hyperalgesia) appeared in both ears, paws and tail, and depended on the sex and the genetic background of the studied strains. This model is a robust platform to study genetic mechanisms underlying CNP that is seen frequently in humans, especially women. Our specific aims are to identify candidate genetic factors that contribute to differences in susceptibility to CNP. Since, some of these likely encode voltage- and ligandgated ion channel genes, in AIM-1 we will identify SNPs in 235 such genes across 20 inbred mouse strains and reconstruct their haplotypes. AIM-2: Phenotyping CNP post-IONX in these mice and a computational genetic analysis of their haplotype map, we will identify genetic factors controlling CNP. Phenoirping 23 AXB-BXA recombinant inbred mouse strains, followed by linkage analysis of their known genetic map will enable us to idenbfy QTL intervals for CNP. Using expression arrays we will identify genes differentially expressed in trigeminal subnucleus caudalis (Vc) of strains contrasting on CNP levels post-IONX. Superposition of these 3 maps should enable candidate genes for CNP to be identified. Not part of this study, we will genotype these genes in cohorts of trigeminal (and other) neuropathic pain patients. AIM-3: CNP levels in 43 strains typed in AIM 2 will enable us to offer the highest contrasting strains as a standardized new platform to study mechanisms of CNS plasticity after nerve injury, test novel analgesics and produce new hypotheses for indepth future studies. We will phenotype 8 of these strains for traits supposedly correlating CNP and undetlying central plasticity following nerve injury: (i) excitotoxic destruction of pain-suppressing neurons in Vc, (ii) Seizure proneness as a probe of CNS inhibitions, (iii) changes in astro- and microglial cells, and (iv) FOS labeling to study plasticity in somatotic maps of Vc and lumbosacral neuronal pools that respond to acute noxious stimulation in sites of extratenitorial hyperalgesia. These genetic and phenomic studies are proposed as a new and robust model to study trigeminal pain syndromes. Identification of genetic factors affecting trigeminal pain syndromes could provide novel therapeutic targets.