一般口演（Oral）

Oral Axon and glia in Health and diseage 一般口演軸索とグリアによる生理病態制御

7月26日（金）16:10～16:25　第9会場（朱鷺メッセ　3F　306+307） 2O-09a2-1 GLP-1受容体作動薬exendin-4によるミエリン化促進の機構解析 Kazunori Sango（三五一憲），Shizuka Takaku（高久静香），Masami Tsukamoto（塚本雅美），Naoko Niimi（新見直子），Hideji Yako（八子英司）東京都医学総合研・糖尿病性神経障害PJ In addition to its insulinotropic actions on pancreatic β cells, the localization of glucagon-like peptide-1 receptor (GLP-1R) at the nervous system suggests neuroprotective properties of GLP-1. Exendin-4 (Ex-4), a GLP-1R agonist, has been shown to prevent the deterioration of neurons and glial cells following axonal injury and in a variety of neurodegenerative disorders. Although the neurotrophic actions of Ex-4 on primary cultured adult rat dorsal root ganglion (DRG) neurons have been reported, its underlying beneficial effects on myelination and remyelination remain unknown. In this study, DRG neurons were seeded onto type I collagen-coated Aclar coverslips and 2-well chamber slides and maintained in a serum-free culture medium for 7 days. Neurite outgrowth was observed under a phase-contrast microscope, following which DRG neurons were co-cultured with immortalized adult rat Schwann cells IFRS1 under a serum-free medium supplemented with 50 μg/mL ascorbic acid and different concentrations (0, 10, or 100 nM) of Ex-4 for up to 21 days. Under a phase-contrast microscope, treatment with Ex-4 dose-dependently promoted the movement of IFRS1 cells toward the neurites growing from DRG neurons at 14 days of co-culture. Immunofluorescence and Western blotting performed at 21 days of co-culture revealed that Ex-4 significantly increased the number of myelin protein zero (MPZ)-immunoreactive IFRS1 cells surrounding βIII tubulin-immunoreactive neurites, and up-regulated the protein expression of MPZ and peripheral myelin protein 22 (PMP22). Moreover, Western blotting performed at 3 days of co-culture resulted in Ex-4-induced phosphorylation of AKT, suggesting that Ex-4 accelerates the myelination process in the co-culture via activating PI3 kinase/AKT pathway. These findings imply the efficacy of Ex-4 in accelerating axonal regeneration and remyelination following peripheral nerve injury, as well as preventing and restoring peripheral neuropathies.		7月26日（金）16:25～16:40　第9会場（朱鷺メッセ　3F　306+307） 2O-09a2-2 脂肪酸伸長酵素ELOVL1欠損マウスはミエリンのスフィンゴ脂質の短鎖化と減少，ミエリン低形成，協調運動障害を示す Takayuki Sassa（佐々貴之），Masashi Isokawa（磯川昌志），Akio Kihara（木原章雄）北海道大院薬 Myelin is highly enriched in lipids. Almost one-third of myelin lipids is occupied by sphingolipids, which are predominantly galactosylceramides and sphingomyelins. The most remarkable feature of sphingolipids in myelin is that their acyl moieties predominantly consist of saturated or monounsaturated form of very long-chain fatty acids (VLCFAs), the fatty acids with carbon chain lengths of >C20. VLCFAs are synthesized via the fatty acid elongation cycles in the endoplasmic reticulum. Among the seven isozymes of mammalian fatty acid elongases, ELOVL1 is expressed in the brain and involved in the synthesis of saturated and monounsaturated C22-C26 VLCFAs, suggesting ELOVL1 being the major isozyme responsible for the synthesis of VLCFAs present in myelin lipids. Recently, de novo mutation in ELOVL1 gene was found in patients exhibiting many symptoms including hypomyelination and spastic paraplegia (1). However, the detailed brain pathology and its relation to lipids having VLCFAs were unclear. Here we analyzed Elovl1 knockout (KO) mice as the mouse model of human ELOVL1 deficiency. The acyl moieties of sphingolipids, such as galactosylceramides, sphingomyelins, and ceramides, were pronouncedly shortened from C22-C24 in wild-type mice to ≤C20 in Elovl1 KO mice. Moreover, the total amount of galactosylceramides, which are important for myelin formation and maintenance, was reduced to about 60% of that in wild-type mice. Electron microscopy revealed the modest reduction in the fraction of myelinated axons in the corpus callosum. Furthermore, Elovl1 KO mice exhibited decreased moving speed and increased paw slips in a balance beam test, indicating impairment in motor coordination. These results suggest that the decrease in VLCFAs in myelin sphingolipids is associated with neural symptoms observed in patients with ELOVL1 mutation.

7月26日（金）16:40～16:55　第9会場（朱鷺メッセ　3F　306+307） 2O-09a2-3 視神経傷害におけるグリア細胞ATF6α経路の神経保護的役割 Mika Takarada-Iemata（宝田美佳）¹，Yoshiki Koriyama（郡山恵樹）²，Nahoko Okitani（沖谷なほ子）¹，Tsuyoshi Hattori（服部剛志）¹，Hiroshi Ishii（石井宏史）¹，Kazutoshi Mori（森和俊）³，Ryosuke Takahashi（高橋良輔）⁴，Osamu Hori（堀修）¹ ¹金沢大院医薬保健神経解剖 ²鈴鹿医療科学大院薬神経薬理 ³京都大院理生物物理 ⁴京都大院医臨床神経 Accumulating evidence suggests a crucial role of the unfolded protein response (UPR) in neuropathological conditions such as brain ischemia, trauma and neurodegeneration. However, how does UPR affect to the neuro-glia interaction in neurodegenerative condition is not fully understood. We have reported the role of UPR in glial activation in the mouse model of brain stroke, Parkinson's disease and multiple sclerosis. In this study, we investigated the relevance of ATF6α, a key transducer of the UPR signaling, in optic nerve crush injury (ONI), a simple neurodegeneration model which also used as a mouse model of glaucoma. RT-qPCR analysis revealed increased expression of GRP78, a downstream molecule of ATF6α. Immunohistochemical analysis using loss of function mice revealed that lack of ATF6α significantly exacerbated degeneration of retinal ganglion cells, which was determined by the decreased number of βIII-tubulin-positive cells in flat-mounted retinas after ONI. ATF6α knockout mice also showed lower expression levels of GFAP, a marker of activation of Müller cells and astrocytes, and neurotrophic factor after ONI compared to wild-type mice. ER stress exposure to retinal glia in culture system resulted in reduced expression of glial markers and neurotrophic factor. Furthermore, administration of chemical chaperone into mice ameliorated degeneration of retinal ganglion cells in ATF6α knockout mice after ONI. These results suggest that ATF6α may have important role in the survival of retinal ganglion cells through the promotion of glial neuroprotective function in the process of neurodegeneration such as glaucoma.		7月26日（金）16:55～17:10　第9会場（朱鷺メッセ　3F　306+307） 2O-09a2-4 ALSマウスモデル由来初代神経培養細胞のマイクロデバイスを用いた定量的軸索輸送解析 Asako Otomo（大友麻子）^1,2，Takashi Kushida（串田隆志）³，Tomoyuki Ishida（石田智之）³，Ryosuke Araki（荒木良介）³，Shun Mitsui（三井駿）¹，Suzuka Ono（小野鈴花）¹，Kai Sato（佐藤海）¹，Hiroshi Kimura（木村啓志）^2,3，Shinji Hadano（秦野伸二）¹ ¹東海大・医・分生 ²東海大・マイクロナノ研究開発セ ³東海大・工・機械 Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by selective degeneration of motor neurons. Recent studies have demonstrated that impaired cellular proteostasis is implicated in the etiology of several neurodegenerative diseases including ALS. Previously, we have shown that autophagosome-like structures with membrane whorls are accumulated in the spinal axons of a mutant SOD1 transgenic mouse ALS model (SOD1^H46R) as disease progresses. This suggests that perturbations in axonal transport lead to defects in the autophagic pathway and thus normal cellular proteostasis in the diseased neurons. However, the exact causal relationship between neurological deficits and defective axonal transport is not fully understood.To clarify whether axonal transport of acidic vesicles including autophagosome and of mitochondria was affected by overexpression of mutant SOD1, we conducted a quantitative analysis of the axonal transport in primary cultured cortical neurons by using a microdevice. Compared to wild-type (WT) mice, neurons derived from SOD1^H46R showed a significantly increased number of acidic vesicles moving along the distal axons, indicating an enhanced transport of autophagosomes in diseased axons. By contrast, mitochondria moving along the distal axons were significantly decreased in SOD1^H46Rcompared to WT. Our results demonstrated that, at least in in vitro culture model, the axonal transport of not only acidic vesicles but also mitochondria were altered in the distal axon of mutant SOD1-expressing neurons. These findings suggest that defects in the axonal transport can deregulate axonal homeostasis including proteostasis in diseased neurons, thereby ultimately accelerating neurodegeneration.