e ポスター 7. グリア (アストロサイト）
e Poster 7. Glia (astrocyte) |
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| 2020/9/11 14:00～15:00 オンデマンドB-1
P2-10
小胞体膜貫通型転写因子OASISを介したグリオーマ細胞の老化と癌化制御
Regulations of senescence in glioblastoma and tumorigenesis mediated by ER-resident transcription factor OASIS
*齋藤 敦1、藤原 佐知子1、吉丸 哲郎2、松下 洋輔2、片桐 豊雅2、今泉 和則1
1. 広島大学大学院医系科学研究科 分子細胞情報学、2. 徳島大学先端酵素学研究所 プロテオゲノム研究領域 ゲノム制御学分野
*Atsushi Saito1, Sachiko Fujiwara1, Tetsuro Yoshimaru2, Yosuke Matsushita2, Toyomasa Katagiri2, Kazunori Imaizumi1
1. Dept. Biochem., Inst. Biomed. & Health Sci., Hiroshima Univ., 2. Div. Genome Med., Inst. Adv. Med. Sci., Tokushima Univ.
Cellular senescence is a highly stable cell cycle arrest induced in response to various cellular stress including DNA damage. This phenomenon is focused as a defence system against tumorigenesis by attenuating cell proliferation. We found that ER-resident transmembrane transcription factor OASIS, specifically expressed in astrocytes in central nervous system, is activated by DNA damage. The activated OASIS by DNA damage directly induced the expressions of senescence marker p21. Next, we examined the expression of OASIS in cancer cells, because cellular senescence is closely involved in tumorigenesis. The expression of OASIS was attenuated in several tumors and cancer cell-lines including human glioblastoma U251MG cells due to the hyper methylation of its promoter region. BrdU and SA-beta-gal assays showed the inhibited proliferation and the acceleration of cellular senescence in U251MG cells stably expressing OASIS. Xenograft experiments using the cells stably expressing OASIS exhibited the inhibited tumorigenesis and highly senescent status, consistent with those of in vitro experiments. We further tried to specifically promote demethylation of Oasis promoter by using epigenome editing technique. DNA demethylase TET1 conjugated with mutant Cas9 lacking DNA cleavage-ability was simultaneously expressed with guide RNA (gRNA) recognizing Oasis promoter into U251MG cells by all-in-one system. Methylation status of Oasis promoter was decreased in the cells expressing Oasis promoter-targeting gRNA. These cells exhibited the inhibited proliferation and the enhanced senescent status. Since the epigenome editing technique we showed can regulate cellular senescence without genome editing processes, our approach may develop novel and safety therapeutic strategies for glioblastoma. | | 2020/9/11 14:00～15:00 オンデマンドB-1
P2-11【演題取消】
| | 2020/9/11 14:00～15:00 オンデマンドB-1
P2-12
ABCA1欠損は緑内障発症過程早期でのグリオーシスを誘導する
Lack of astrocytic ABCA1 causes early reactive gliosis during pathogenesis of glaucoma
*篠崎 陽一1,2、行方 和彦3、柏木 賢治4、大野 伸彦5,6、繁冨 英治1,2、原田 高幸3、小泉 修一1,2
1. 山梨大学大学院総合研究部医学域基礎医学系 薬理学講座、2. 学際的脳-免疫研究センター、3. 視覚病態プロジェクト 東京都医学総合研究所、4. 山梨大学大学院総合研究部医学域臨床医学系 眼科学講座、5. 超微形態研究部門 生理学研究所、6. 自治医科大学 解剖学講座
*Youichi Shinozaki1,2, Kazuhiko Namekata3, Kenji Kashiwagi4, Nobuhiko Ohno5,6, Eiji Shigetomi1,2, Takayuki Harada3, Schuichi Koizumi1,2
1. Dept. Neurophatmacol., Interdiscp. Grad. Sch. Med., Univ. Yamanashi, 2. Interdiscp. Brain-Immune Res. Cent., Univ. Yamanashi, 3. Vis. Res. Project, Tokyo Metr. Inst. Med. Sci., 4. Dept. Ophthalmol, Interdiscip. Grad. Sch. Med. Univ. Yamanashi, 5. Div. Ultrastruct. Res., Natl. Inst. Physiol. Sci., 6. Div. Anatomy, Jichi Med. Univ.
Glaucoma, the first cause of blindness in Japan, is characterized by progressive degeneration of retinal ganglion cells (RGCs) which transmit visual function to the brain. Although an elevated intraocular pressure (IOP) is considered to be one of the major risk factors, many glaucoma patients, especially in an Asian population, show normal levels of IOP (i.e. normal-tension glaucoma, NTG). Accumulating evidence has suggested that many risk factors other than IOP are involved in the etiology of glaucoma. Recent genome-wide association studies (GWAS) have identified that single nucleotide polymorphism (SNP) of the ABCA1 gene is the highest risk for glaucoma. To clarify the mechanism, we first analyzed conventional ABCA1 knockout (KO) mice. ABCA1KO mice showed no IOP elevation regardless of their age. Importantly, ABCA1KO mice at middle-age (12 months old) showed a moderate but significant reduction in the number of RGCs. We found that ABCA1 was enriched in ocular astrocytes in the retina and optic nerve. To reveal the role of astrocytic ABCA1, we knocked down the Abca1 gene under the control of the GFAP promotor (i.e. cKO mice). Similar to ABCA1KO mice, the cKO mice showed no IOP elevation and age-associated degeneration of RGCs. The cKO mice showed also impaired visual functions at middle-age, indicating that cKO mice exhibit the phenotype of NTG. Gene expression profiling and immunohistochemical analysis demonstrated that astrocytes already became reactive in optic nerve head (ONH) at 3 months old when RGCs showed no damages. Taken together, our data showed that (1) ABCA1 has no impact on IOP; (2) loss-of-function of ABCA1 is involved in glaucoma; and (3) early reactive astrogliosis would contribute to the pathogenesis of NTG. | | 2020/9/11 14:00～15:00 オンデマンドB-1
P2-13
結節性硬化症モデルマウスにおける、アストロサイトの異常に起因した社会記憶の悪化
Astrocyte-mediated impaired social memory in tubular sclerosis complex model mouse
*島田 忠之1、杉浦 弘子1、山形 要人1
1. 東京都医学総合研究所 シナプス可塑性研究室
*Tadayuki Shimada1, Hiroko Sugiura1, Kanato Yamagata1
1. Tokyo Metropolitan Institute of Medical Science, Laboratory of Synaptic Plasticity
Mutations in the Tsc1 gene cause tuberous sclerosis complex (TSC). TSC patients harbor hamartomas in the brain and other organs. The neuropsychiatric symptoms of TSC patients include refractory epilepsy, autism spectral disorders and mental retardation. To investigate if the brain astrocytes contribute to the neuropsychiatric symptoms of TSC patients, we developed astrocyte-specific Tsc1 knockout mice (cKO mouse) and examined their phenotypes. Three-chamber test analysis revealed that the cKO mice showed impaired social memory. In addition, immunohistochemical analyses showed that GFAP-positive cells were increased in the brain, especially in the hippocampus, piriform cortex, and amygdala. Moreover, the malformed dendritic spines were observed in dentate gyri in hippocampi, where one of the most severe gliosis were observed. Tsc1 protein makes a complex with Tsc2 and inactivates Rheb protein together. Treatment with Rheb inhibitors restored abnormal behaviors of the cKO mice and spine malformation. Gliosis in dentate gyrus was also mitigated by Rheb inhibitor administration. In addition, the cultured astrocytes from cKO mice induced abnormal spine shape in the cultured wild type neuron, and Rheb inhibitor recovered astrocyte-dependent abnormal spine morphogenesis in vitro. Activation of the Tsc/Rheb signaling in the astrocytes could induce astrogliosis, affecting the spine morphology by the crosstalk between the astrocytes and neurons. The spine deformity causes deterioration of neural function and would develop abnormal social behaviors observed in a mouse model of TSC. | | 2020/9/11 14:00～15:00 オンデマンドB-1
P2-14*
外傷性脳損傷において2ccPAはアストロサイトを介して神経保護に寄与する
2-carba-cyclic phosphatidic acid contributes to the neuroprotection via astrocytes in traumatic brain injury
*中島 麻里1,2、橋本 恵2、濱野 文菜1,2、池島（片岡） 宏子4、後藤 真里2,3、室伏 きみ子3、宮本 泰則1,2
1. お茶の水女子大学大学院人間文化創成科学研究科 ライフサイエンス専攻、2. お茶の水女子大学 ヒューマンライフイノベーション研究所、3. お茶の水女子大学 ヒューマンウェルフェアサイエンス研究教育寄付研究部門、4. 早稲田大学理工学術創造理工学部
*Mari Nakashima1,2, Kei Hashimoto2, Ayana Hamano1,2, Hiroko Ikeshima-Kataoka4, Mari Gotoh2,3, Kimiko Murakami-Murofushi3, Yasunori Miyamoto1,2
1. Div. of Life Sci., Grad. Sch. of Humani. Sci., Ochanomizu Univ., 2. Inst. for HLI., Ochanomizu Univ., 3. Research Div. of HWS., Ochanomizu Univ., 4. Faculty of Sci. and Engineering, Waseda Univ.
2-carba-cyclic phosphatidic acid (2ccPA) is metabolically stabilized derivative of cyclic phosphatidic acid (cPA), one of the lipid mediator. In the nervous system, 2ccPA exhibits neuroprotective effects on neuronal death in hippocampal neurons. Traumatic brain injury (TBI) is caused by physical damage, and the damage results in inflammation and neuronal death.
In this study, to investigate the effect of 2ccPA on the neuroprotective function after TBI, we analyzed the neurosurvival in the wounded regions. The administration of 2ccPA reduced the number of apoptotic neurons, indicating that 2ccPA suppresses the neuronal death. To elucidate the mechanism underlying the neuroprotective effects of 2ccPA, we focused astrocytes which play a critical role in neuroprotection. First, we analyzed the mRNA and protein expression level of the glial fibrillary acidic protein (GFAP), a marker of astrocytes around the lesion. 2ccPA suppressed the mRNA and protein expression level of GFAP, suggesting that 2ccPA induces the secretion of neuroprotective factor from astrocytes and attenuates the neuronal death after TBI.
Next, we focused on one of extracellular matrix protein, tenascin-C (TNC), of which expression is upregulated in astrocytes in injured brain. 2ccPA increased the number of TNC-positive astrocytes in the early stages of injury. In primary culture of astrocytes, the expression level of TNC mRNA was increased by 2ccPA, and further, the protein level of TNC in the conditioned medium of primary culture of astrocytes was increased by 2ccPA. The addition of the conditioned medium suppressed the apoptosis of cortical neuron. These results suggest that 2ccPA up-regulates the secretion of TNC and contributes to the neuroprotection via astrocytes in traumatic brain injury. | | | |
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