Oral
Movement Disorders
一般口演
運動機能障害 |
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| 7月28日（日）10:50～11:05 第8会場（朱鷺メッセ 3F 303+304）
4O-08a1-1
マイオジェニンの発現制御に関与する新規lncRNAの機能解析と筋萎縮治療
Kunihiro Tsuchida（土田 邦博），Keisuke Hitachi（常陸 圭介），Masashi Nakatani（中谷 直史）
藤田医科大学総医研難病治療学研究部門
The differentiation process of skeletal muscle cells, called myogenesis, has been studied as a model of cell differentiation systems. One of the myogenic regulatory factors (MRFs), MyoD, triggers the expression of cyclin-dependent kinase inhibitors to arrest the cell cycle of proliferating myoblasts and also initiates the expression of early skeletal muscle-specific genes including myogenin, coding one MRF. Subsequently, MyoD and myogenin promote the entry of myoblasts into the myogenic differentiation lineage through the activation of later skeletal muscle-specific genes. Additionally, muscle-specific microRNAs (miRNAs) broaden the regulatory networks of myogenesis by modulating the expression of target genes in myoblast proliferation and differentiation. Thus, induction of muscle-specific genes coordinated with the cell cycle exit at an appropriate time is required for the formation of terminally differentiated skeletal muscle cells.
Myogenin gene is indispensable for skeletal muscle development. The expression of myogenin is highly restricted to myogenic tissues in embryonic, fetal, and adult skeletal muscles. Myogenin also induces skeletal muscle atrophy by nerve injury and degenerative diseases. However, the mechanisms inducing high-level myogenin expression in skeletal muscle cells have not been elucidated.
Promoter-associated long non-coding RNAs (lncRNAs) regulate the expression of adjacent genes; however, precise roles of these lncRNAs in skeletal muscle remain largely unknown. Here, we characterize a promoter-associated lncRNA, Myoparr, in myogenic differentiation and muscle disorders. Myoparr is expressed from the promoter region of the mouse and human myogenin gene, one of the key myogenic transcription factors. We show that Myoparr is essential both for the specification of myoblasts by activating neighboring myogenin expression and for myoblast cell cycle withdrawal by activating myogenic microRNA expression. Mechanistically, Myoparr interacts with Ddx17, a transcriptional coactivator of MyoD, and regulates the association between Ddx17 and the histone acetyltransferase PCAF Myoparr also promotes skeletal muscle atrophy caused by denervation, and knockdown of Myoparr rescues muscle wasting in mice. Our findings demonstrate that Myoparr is a novel key regulator of muscle development and suggest that Myoparr is a potential therapeutic target for neurogenic atrophy in humans. | | 7月28日（日）11:05～11:20 第8会場（朱鷺メッセ 3F 303+304）
4O-08a1-2
アクテオサイドは新マイオカインの分泌を促すことで慢性期脊髄損傷の骨格筋萎縮と運動機能する改善する
Chihiro Tohda（東田 千尋），Atsushi Kodani（小谷 篤），Takahiro Kikuchi（菊池 高広）
富山大和漢研神経機能学
Chronic spinal cord injury (SCI) is difficult to cure, even by several approaches effective at the acute or subacute phase. Although the majority of SCI studies have focused on the nervous system and inflammatory cells in the spinal cord, we targeted skeletal muscle atrophy, as a characteristic finding in the chronic phase. Because, a longitudinal study showed that skeletal muscle atrophy progresses in a manner dependent on the time after injury in humans. Disuse of skeletal muscle and loss of motor neurons synergistically induce muscle atrophy. On the contrary, exercise was shown to slightly improve motor function when applied during the chronic phase. Although skeletal muscle secretes myokines responded to muscle activity, we considered that some myokines might regulate neural function. Thus, we hypothesized that stimulation of skeletal muscle with drugs rather than exercise might activate the release of known or yet unknown myokines, with the notion that the identification of such drugs and new myokines would pave a new way of therapy for SCI.
We explored drugs that protect against muscle atrophy and activate secretion of axonal growth factors from skeletal muscle, and found that acteoside induced the secretion of axonal growth factors from skeletal muscle cells and proliferation of these cells. Intramuscular injection of acteoside in mice with chronic SCI recovered skeletal muscle weight reduction and motor function impairment. We also identified pyruvate kinase isoform M2 (PKM2) as a secreted factor from skeletal muscle cells, stimulated by acteoside. Extracellular PKM2 enhanced proliferation of skeletal muscle cells and axonal growth in cultured neurons. Further, we showed that PKM2 might cross the blood-brain barrier. These results indicate that effects of acteoside on chronic SCI might be mediated by PKM2 secretion from skeletal muscles. This study proposes that the candidate drug acteoside and a new myokine, PKM2, could be used for the treatment of chronic SCI. | | 7月28日（日）11:20～11:35 第8会場（朱鷺メッセ 3F 303+304）
4O-08a1-3
脂肪組織におけるパーキンソン病関連タンパク質LRRK2の機能解析
Motoki Imai（今井 基貴）1，Fumitaka Kawakami（川上 文貴）1，Yuki Isaka（井阪 勇輝）1，Makoto Kanzaki（神崎 展）2，Takafumi Ichikawa（市川 尊文）1
1北里大院医生体制御生化学
2東北大学大学院 医工学研究科医工学専攻 病態ナノシステム医工学
Background
Parkinson's disease (PD) is the second most common neurological disorder after Alzheimer's disease. Although recent genetic studies have revealed a genetic basis for familial and sporadic PD, the pathological mechanisms are not fully understood. A recent study showed that many PD patients have abnormalities of glucose metabolism and reported that PD associated with type-2 diabetes. However, the physiological interaction between neurodegeneration and abnormal glucose metabolism in PD pathogenesis remains to be elucidated. In the our preliminary experiments, we found that LRRK2 highly expressed in the mouse adipose tissue. Therefore, in the present study, we investigated the role of LRRK2 in the glucose metabolism using a high-fat diet-induce obesity mouse model and 3T3-L1 adipocyte cell line.
Methods
5 weeks old male C57BL/6J wild type (WT) and LRRK2 knockout (KO) mice were used in this study. These mice were fed a normal diet (ND) or high-fat diet (HFD) for 5 months. At the periods of 1, 3, and 5 months, the oral glucose tolerance test (OGTT) was performed. The expression and phosphorylation of LRRK2 and glucose metabolism related molecules, such as GLUT4, AKT, AMPK, and Rab GTPase in the adipose tissue were determined by western blotting. Moreover, effect of LRRK2 kinase activity on the membrane translocation of GLUT4 and phosphorylation state of AKT, AMPK, and Rab GTPase in the 3T3-L1 cells were determined by treatment with LRRK2 kinase inhibitors, CZC24156 and MLi-2.
Results and Discussion
In the present study, we found that HFD-fed KO mice display improved glucose tolerance compared with HFD-fed WT mice. Moreover, it was found that LRRK2 expression and phosphorylation of Rab8a and Rab10 were significantly elevated in adipose tissue of HFD-fed WT mice whereas the expression and phosphorylation of GLUT4, AKT, and AMPK were not altered. Next, we found that LRRK2 inhibitor stimulated membrane translocation of GLUT4 and significantly increase AMPK phosphorylation in differentiated 3T3-L1 adipocyte. In contrast, phosphorylation of Rab8a and Rab10 were significantly decreased by LRRK2 inhibitors. These results suggest that increased LRRK2 expression and kinase activity may downregulates glucose uptake by inhibition of Rab GTPase-mediated GLUT4 membrane translocation in adipose. | | 7月28日（日）11:35～11:50 第8会場（朱鷺メッセ 3F 303+304）
4O-08a1-4
パーキンソン病モデルマーモセット運動機能の行動解析システムの作成
Louie R Ueno-Nigh（上野-ナイ R 瑠惟），Takao Oishi（大石 高生），Masahiko Takada（高田 昌彦）
京都大学霊長類研究所統合脳システム分野
Parkinson's disease (PD) is a serious movement disorder characterized primarily by akinesia, tremor, and rigidity, which is due to disruption of the nigrostriatal dopaminergic pathway. Investigations of the pathophysiology of PD are still crucial, because the causes and treatments of the disease are different from case to case. Common marmoset monkeys (Callithrix jacchus) become increasingly popular as a primate model for basic and advanced research works on PD. In the present study, we therefore designed a staircase device to monitor reaching and grasping motor behaviors of marmosets automatically via infrared sensors linked to a compact computer. In this device, marmosets can extend one arm through an aperture to grasp reward from a five-step staircase on their right or left, with higher steps representing greater difficulties. Two different measures were also employed to determine whether marmosets manifest parkinsonian symptoms. One is a six-tube task in which an animal searches an array of six film canisters to retrieve a food pellet placed inside. As parkinsonian symptoms progress, it is expected that the extent to which the affected hand is used will decrease. The other is an overhead video recording system which allows us to observe general motor activity of an animal. Then, we intend to perform unilateral injections of an adeno-associated viral vector into the substantia nigra to induce overexpression of a pathogenic type of alpha-synuclein specifically in dopaminergic neurons, and monitor behavioral alterations in such a PD model of marmosets. | |
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