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Analysis of neuronal responses against disruption of paranodal junction

Kazuo Kunisawa1*, Takeshi Shimizu1, 2, Nobuhiko Hatanaka2, 3, Yasuyuki Osanai1, Kenta Kobayashi2, 4, Akiko Hayashi5, Hiroko Baba5, Atsushi Nambu2, 3, Itaru Kushima6, Norio Ozaki6, Manzoor A. Bhat7 and Kazuhiro Ikenaka1, 2
  • 1 National Institute for Physiological Sciences (NIPS), Division of Neurobiology and Bioinformatics, Japan
  • 2 SOKENDAI (Graduate University for Advanced Studies), Department of Physiological Sciences, School of Life Sciences, Japan
  • 3 NIPS, Division of System Neurophysiology, Japan
  • 4 NIPS, Section of Viral Vector Development, Japan
  • 5 Tokyo University of Pharmacy and Life Sciences, Department of Molecular Neurobiology, Japan
  • 6 Nagoya University Graduate School of Medicine, Department of Psychiatry, Japan
  • 7 University of Texas Health Science Center, Department of Physiology, United States

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.

Keywords: Electrophysiology, in vivo, Myelinated axon, Paranodal junction, neuronal gene

Conference: 14th Meeting of the Asian-Pacific Society for Neurochemistry, Kuala Lumpur, Malaysia, 27 Aug - 30 Aug, 2016.

Presentation Type: Poster Presentation Session

Topic: 14th Meeting of the Asian-Pacific Society for Neurochemistry

Citation: Kunisawa K, Shimizu T, Hatanaka N, Osanai Y, Kobayashi K, Hayashi A, Baba H, Nambu A, Kushima I, Ozaki N, Bhat MA and Ikenaka K (2016). Analysis of neuronal responses against disruption of paranodal junction. Conference Abstract: 14th Meeting of the Asian-Pacific Society for Neurochemistry. doi: 10.3389/conf.fncel.2016.36.00179

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Received: 04 Aug 2016; Published Online: 11 Aug 2016.

* Correspondence: Dr. Kazuo Kunisawa, National Institute for Physiological Sciences (NIPS), Division of Neurobiology and Bioinformatics, Okazaki, Aichi, Japan, kuni716@gmail.com