CK2-Olr81相互作用影响晕动症易感性的机制

The individual difference of motion sickness susceptibility is great, but the related molecular mechanism is still unclear. We found that motion sickness susceptibility in humans is associated with the single nucleotide polymorphism of rs57026471 in C terminal of intracellular region of OR52J3-the human homology of olfactory receptor Olr81 in rat. Our proteomics study revealed that C terminal of intracellular region of OR52J3 significantly interacts with α and β subunit of casein kinase 2 (CK2) and co-expresses with each other in the vestibular nucleus. It is known that CK2 can affect the memebrane surfacing and activity of glutamatergic NMDA receptor and cholinergic M3 receptor via phosphorylation regulation. It also can regulate the process of phosphorylation and acetylation of histones, affect gene expression and subsequently enhance the endurance to special environment. In this project, we will observe the difference in the interaction between CK2 and Olr81 or its mutants and its effects on memebrane surfacing and activity of NMDA and M3 receptor. We also try to explore the effect of CK2-Olr81 interaction on epigenetics character and related gene expression profile in vestibular nucleus neurons in newborn and adult rats exposed to acceleration repeatedly. The purpose of these experiments is to clarify molecular mechanism underlying the involvement of CK2-Olr81 interaction in motion sickness susceptibility and provide a novel way to enhance motion sickness endurance in susceptible subjects.

晕动症易感性存在显著的个体差异，但相关分子机制尚不清楚。我们发现人群晕动症易感性与嗅觉受体Olr8(人同源性受体OR52J3)胞内段C端rs57026471位点基因多态性相关；通过蛋白组学实验发现OR52J3受体胞内段C端多肽与前庭核内酪蛋白激酶2（CK2）α和β亚单位具有较强相互作用，并在前庭核共表达；已知，CK2可通过磷酸化作用影响谷氨酸NMDA受体及胆碱能M3受体膜表达及活性，亦可调节组蛋白磷酸化及乙酰化过程，影响基因表达，以提高机体对特殊环境的耐受力；本研究拟观察CK2与Olr81及其突变体结合活性的差异，及对前庭核神经元NMDA及M3受体膜表达及活性的影响；探索CK2-Olr81相互作用对新生及成年大鼠反复加速度暴露后，前庭核神经元表观遗传变化特征及所调控的相关基因表达的影响，以期阐明CK2-Olr81相互作用影响晕动症易感性的分子机制，为提高易感人群晕动症耐受能力提供新途径。

晕动症易感性存在显著的个体差异，但其确切的分子机制尚不清楚。本研究发现pAd-miOlr81处理下调尾测前庭核Olr81表达，显著抑制晕动症易感（MSS）大鼠旋转刺激后的行为学（条件性张口，自发活动和平衡杆通过时间）变化，引起Olr81和NMDA受体NR2A亚单位膜蛋白表达水平以及AC/PKA/cAMP信号通路活性显著下降。相反，pAd-Olr81注射上调Olr81表达，可诱发晕动症不易感（inMSS）动物的晕动症行为学反应，使Olr81、NR2A膜蛋白表达水平以及AC/PKA/cAMP信号通路活性显著升高。免疫共沉淀实验发现，Olr81的rs57026471的TT纯合突变体与酪蛋白激酶2α（CK2α）催化亚单位的相互作用与野生型相比无显著差异。将rs57026471位点CC纯合，CT杂合及TT纯合OR52J3（Olr81人同源蛋白）转染SY5Y神经瘤细胞后，NMDA受体NR2A及NR2B亚单位总蛋白表达水平均显著升高，TT纯合OR52J3转染组NR2A及NR2B总蛋白表达明显高于CC纯合组和 GFP转染对照组（P < 0.01）。CK2抑制剂（CX4945）及PKA抑制剂（H89 2Cl）可使NR2A及NR2B总蛋白水平显著下降，CX4945及H89 2Cl均显著抑制inMSS动物注射pAd-Olr81后引起的晕动症行为学反应和AC/PKA/cAMP信号通路活性。甲基化测序结果显示，新生动物反复加速度暴露后与成年动物比较,共获得基因启动子区域DMR相关基因503个，上述研究结果表明，Olr81通过与CK2相互作用通过调控AC/PKA/cAMP信号通路活性调节NR2A及NR2B总蛋白表达水平。新生及成年大鼠反复加速度暴露后，前庭核基因表观遗传特征具有显著差异。