Sugeno Ayaka, Piao Wenhui, Yamazaki Miki, Takahashi Kiyofumi, Arikawa Koji, Matsunaga Hiroko, Hosokawa Masahito, Tominaga Daisuke, Goshima Yoshio, Takeyama Haruko, Ohshima Toshio
Laboratory for Molecular Brain Science, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University; Computational Bio Big-Data Open Innovation Laboratory (CBBD-OIL), National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan.
Laboratory for Molecular Brain Science, Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.
Neural Regen Res. 2021 Jul;16(7):1258-1265. doi: 10.4103/1673-5374.301035.
Recent studies have shown that mutation at Ser522 causes inhibition of collapsin response mediator protein 2 (CRMP2) phosphorylation and induces axon elongation and partial recovery of the lost sensorimotor function after spinal cord injury (SCI). We aimed to reveal the intracellular mechanism in axotomized neurons in the CRMP2 knock-in (CRMP2KI) mouse model by performing transcriptome analysis in mouse sensorimotor cortex using micro-dissection punching system. Prior to that, we analyzed the structural pathophysiology in axotomized or neighboring neurons after SCI and found that somatic atrophy and dendritic spine reduction in sensorimotor cortex were suppressed in CRMP2KI mice. Further analysis of the transcriptome has aided in the identification of four hemoglobin genes Hba-a1, Hba-a2, Hbb-bs, and Hbb-bt that are significantly upregulated in wild-type mice with concomitant upregulation of genes involved in the oxidative phosphorylation and ribosomal pathways after SCI. However, we observed substantial upregulation in channel activity genes and downregulation of genes regulating vesicles, synaptic function, glial cell differentiation in CRMP2KI mice. Moreover, the transcriptome profile of CRMP2KI mice has been discussed wherein energy metabolism and neuronal pathways were found to be differentially regulated. Our results showed that CRMP2KI mice displayed improved SCI pathophysiology not only via microtubule stabilization in neurons, but also possibly via the whole metabolic system in the central nervous system, response changes in glial cells, and synapses. Taken together, we reveal new insights on SCI pathophysiology and the regenerative mechanism of central nervous system by the inhibition of CRMP2 phosphorylation at Ser522. All these experiments were performed in accordance with the guidelines of the Institutional Animal Care and Use Committee at Waseda University, Japan (2017-A027 approved on March 21, 2017; 2018-A003 approved on March 25, 2018; 2019-A026 approved on March 25, 2019).
最近的研究表明，Ser522位点的突变会抑制塌陷反应介导蛋白2（CRMP2）的磷酸化，并诱导轴突伸长以及脊髓损伤（SCI）后部分恢复失去的感觉运动功能。我们旨在通过使用显微切割打孔系统对小鼠感觉运动皮层进行转录组分析，揭示CRMP2基因敲入（CRMP2KI）小鼠模型中轴突切断神经元的细胞内机制。在此之前，我们分析了SCI后轴突切断或相邻神经元的结构病理生理学，发现CRMP2KI小鼠感觉运动皮层中的体细胞萎缩和树突棘减少受到抑制。对转录组的进一步分析有助于鉴定四个血红蛋白基因Hba-a1、Hba-a2、Hbb-bs和Hbb-bt，这些基因在野生型小鼠中显著上调，同时SCI后参与氧化磷酸化和核糖体途径的基因也上调。然而，我们观察到CRMP2KI小鼠中通道活性基因大幅上调，而调节囊泡、突触功能和胶质细胞分化的基因下调。此外，还讨论了CRMP2KI小鼠的转录组图谱，其中发现能量代谢和神经元途径受到不同调节。我们的结果表明，CRMP2KI小鼠不仅通过神经元中的微管稳定，还可能通过中枢神经系统的整个代谢系统、胶质细胞和突触的反应变化，改善了SCI的病理生理学。综上所述，我们通过抑制Ser522位点的CRMP2磷酸化，揭示了关于SCI病理生理学和中枢神经系统再生机制的新见解。所有这些实验均按照日本早稻田大学实验动物管理与使用委员会的指导方针进行（2017年3月21日批准的2017-A027；2018年3月25日批准的2018-A003；2019年3月25日批准的2019-A026）。
