2E-道場2-1
Visualization of oligodendrocyte-axon interaction with a combinational injection of attenuated rabies virus and adeno-associated virus.
長内 康幸1,2，清水 健史1,2，森 琢磨2,3,7，吉村 由美子2,3，畑中 伸彦2,4，南部 篤2,4，木森 義隆2,6，小山 慎介2,8，小林 憲太2,5，池中 一裕1,2
1生理学研究所 分子神経生理研究部門，2総合研究大学院大学，3生理学研究所 視覚情報処理研究部門，4生体システム研究部門，5ウイルスベクター開発室，6自然科学研究機構 イメージングサイエンス研究分野，7信州大学医学部 分子細胞生理学講座，8統計数理研究所 統計的機械学習研究センター
Oligodendrocytes myelinate neuronal axons during development and increase conduction velocity of neuronal impulses in the central nervous system（CNS）. Neuronal axons extend from multiple brain regions and pass through the white matter；however, it is unclear whether oligodendrocytes ensheath a particular set of axons or do so randomly within the mammalian brain. We developed a novel method to visualize individual oligodendrocytes and axon extended from a particular brain region in mouse white matter using a combinational injection of viral vectors；attenuated rabies virus and adeno-associated virus. Attenuated rabies virus sparsely labeled oligodendrocytes and adeno-associated virus labeled axons from two distinct brain regions. By use of this technique, we found that some populations of oligodendrocytes predominantly ensheathed axons derived from a particular brain region, while others evenly ensheathed axons from multiple brain regions. This newly established method is a versatile tool for detecting oligodendrocyte-axon interaction in animal models in pathology as well as for addressing oligodendrocyte roles in higher brain functions. | | 2E-道場2-2
Analysis of neuronal responses against disruption of paranodal junction
國澤 和生1，清水 健史1,2，畑中 伸彦2,3，長内 康幸1，小林 憲太2,4，林 明子5，馬場 広子5，南部 篤2,3，久島 周6，尾崎 紀夫6，Bhat Manzoor A.7，池中 一裕1,2
1生理学研究所・分子神経生理，2総合研究大学院大学・生命科学・生理科学，3生理学研究所・生体システム，4生理学研究所・ウイルスベクター開発室，5東京薬科大学・薬・機能形態学，6名古屋大学大学院・医・精神医学，7テキサス健康科学センター大学・生理学
The myelinated axon segregates four defined regions：the node of Ranvier, paranode, juxtaparanode and internode. Although myelin internodes are thought to have crucial roles in cognition and motor functions, the role of paranodal junction in neuronal responses remains unclear. Neurofascin155（NF155）is known to be a glial component of this region. In the previous study, oligodendrocytes-specific deletion of NF155（Plp-CreERT；NF155Flox/Flox mouse）led to disorganization of paranodal junctions. In this study, to determine whether site-directed loss of paranodal junctions affect the latency in vivo, we injected adeno-associated virus type5（AAV5）harboring EGFP-2A-Cre into the internal capsule of NF155Flox/Flox mice, which led to disruption of paranodal junctions in a portion of pyramidal tract. Electrophysiological analysis showed that the latency was significantly delayed in NF155Flox/Flox mice injected with AAV5-EGFP-2A-Cre, compared to the control mice. These results demonstrate that the motor system outputs were affected by focal ablation of the paranodal junctions. To further examine whether disruption of paranodal junctions affect neuronal gene expression, we prepared total RNA from the retina of Plp-CreERT；NF155Flox/Flox mice and control mice, and proceeded to microarray analysis. We found that expression level of various neuronal genes dramatically changed in response to the ablation of paranodal junctions. Interestingly, the expression of some of the genes were significantly higher than that of control in Plp-CreERT；NF155Flox/Flox mice, but not in the cerebroside sulfotransferase knockout（CST-KO）mice, whose paranode has not been originally formed throughout their development. These results suggest that some neuronal genes are sensitive to an early change in the myelin-axon interaction during demyelination, such as paranodal opening. |
