若手道場

若手道場12

2021/10/1　16:00～17:00　ZOOM 若手道場 WD12-1 正常眼圧緑内障モデルマウスにおける視神経伸長を促す薬物の検討 Investigation of drug effects on optic nerve growth in a mouse model of normal tension glaucoma ^○渋江省吾, Chihiro Tohda 富山大学和漢医薬学総合研究所神経機能学領域 ^○Shogo Shibue, Chihiro Tohda Section of Neuromedical Science, Institute of Natural Medicine, University of Toyama Glaucoma is a major cause of irreversible blindness worldwide characterized by degeneration and loss of retinal ganglion cells (RGC). Glaucomatous optic nerve neuropathy is caused by progressive atrophy of the vision system neuraxis. All current drug treatments are focused on lowering intraocular pressure, which are don't accomplish vision recovery. Our laboratory previously found axonal regeneration activity of Drug A (name is closed due to the patent). Therefore, this study aimed to investigate effects of Drug A on optic nerve growth in an optic nerve crush model. As a normal tension glaucoma model, optic nerves of mice were crushed. The right optic nerve behind the eye ball was exposed and crushed for 5 sec by forceps. Immediately after, Drug A or vehicle solution was treated by intravitreal injection. Five days before sacrificing, anterograde tracer, Alexa Fluor-conjugated cholera toxin B (CTB) was intravitreally injected. After measurement of intraocular pressure, retina, the optic nerve and brain were dissected and served for histochemical evaluation. CTB-positive axonal density was quantified in the optic nerve and brain. Optic nerve crush severely reduced RGC numbers and axonal density in the optic nerve at 2 and 3 weeks after the crush. Drug A treatment tended to increase axonal density in the optic nerve although RGC numbers were not changed by Drug A. Optic nerve termination to the lateral geniculate nucleus and superior colliculus are now under investigation. Drug A treatment to primary cultured RGC for 4 days significantly enhanced axon length. This study suggested that Drug A might ameliorate damage of the optic nerve although we need to conduct more detail analyses.		2021/10/1　16:00～17:00　ZOOM 若手道場 WD12-2 ヒトのニューロンにおける神経突起伸長メカニズムの解明と神経突起伸長化合物の探索 Elucidation of neurite outgrowth mechanism in human neurons and search for new compounds that extend neurites ^○加瀬義高¹, Tsukika Sato¹, Yuji Okano¹, Hideyuki Okano¹ 1.Department of Physiology, Keio University School of Medicine, 2.Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo ^○Yoshitaka Kase¹, Tsukika Sato¹, Yuji Okano¹, Hideyuki Okano¹ 1.Department of Physiology, Keio University School of Medicine, 2.Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo Neurites can be elongated by the polymerization of microtubules. However, few signaling cascades have been discovered that control this mechanism in human neurons, and no compound has been found that can extend neurites by promoting the polymerization of microtubules. Here, we found that the new signaling pathway was a key to enhance the neurite outgrowth in human neurons by promoting the polymerization of microtubules. In this study, we induced the expression of neural lineage genes by treating human induced pluripotent stem cell-derived neural stem/progenitor cells with γ-secretase inhibitors and used them as screening samples to identify pathways that elongate neurites. Additionally, Compound Y from Streptomyces sp. was shown to enhance microtubule polymerizations and promote neurite outgrowth by reinforcing this new signaling. Neurites regress and brain dysfunctions increase as time goes by, due to aging and neurodegenerative diseases. Therefore, in terms of regenerative medicine, clarifying the mechanism underlying neurite outgrowth might help to find a cure for neurodegenerative diseases.

2021/10/1　16:00～17:00　ZOOM 若手道場 WD12-3 ミュラー細胞のP2Y1受容体の欠如が網膜神経節細胞の変性を引き起こす Lack of P2Y1 receptors in Müller cells causes degeneration of retinal ganglion cells ^○濱田健太郎¹, 篠崎陽一^1,2, 壇上洋右¹, 久保田友人¹, 夏堀晃世³, 齊藤光像^1,2, ビジェイパラジュリ^1,2, 繁冨英治¹, 柏木賢治⁵, 田中謙二⁴, 小泉修一^1,2 1.山梨大学大学院総合研究部医学域薬理, 2.GLIA Center, Univ. Yamanashi, 3.Sleep disord. project, Tokyo Metr. Inst. Med. Sci., 4.Dept. Neuropsychiat., Keio Univ. Sch. Med., 5.Dept. Ophthalmol., Interdiscp. Grad. Sch. Med. Univ. Yamanashi ^○Kentaro hamada¹, 陽一篠崎^1,2, 洋右壇上¹, 友人久保田¹, 晃世夏堀³, 光像齊藤^1,2, ビジェイパラジュリ^1,2, 英治繁冨¹, 賢治柏木⁴, 健二田中⁵, 修一小泉^1,2 1.Dept. Neuropharmacol., Interdiscip. Grad. Sch. Med. Univ. Yamanashi, 2.GLIA Center, Univ. Yamanashi, 3.Sleep disord. project, Tokyo Metr. Inst. Med. Sci., 4.Dept. Neuropsychiat., Keio Univ. Sch. Med., 5.Dept. Ophthalmol., Interdiscp. Grad. Sch. Med. Univ. Yamanashi Glaucoma is second leading cause of blindness worldwide, and is thought to be caused by degeneration of retinal ganglion cells (RGCs) due to an elevated intraocular pressure (IOP). In the last meeting, we reported that P2Y1 receptor is expressed in angle tissues and plays an essential role for IOP reduction. Thus P2Y1 receptor knockout (P2Y1KO) mice showed higher IOP and hypertensive glaucoma-like phenotype. However, P2Y1 receptor is also highly expressed in astrocyte-lineage cells in the retina. To test the role of P2Y1 receptor in these cell types in physiological and pathophysiological functions in the retina, we selectively deleted P2Y1 receptor in astrocyte-linage cells using Mlc1-tTS::P2ry1tetO/tetO mice. We first investigate which cell type is regulated under control of Mlc1 promotor using Mlc1-tTA::YC-Cameleon-NanotetO/tetO, and found that the gene expression of Müller cells is selectively regulated by the Mlc-1-driver system. Next, we measured IOP of control and Müller cell-specific P2Y1 receptor conditional KO (MC-cKO) mice and found that MC-cKO mice showed no increase in IOP compared to control mice. However we found that MC-cKO mice showed significantly less number of RGCs (Rbpms-positive cells) than control mice at 12 months old (mo). In accordance with this, the number of apoptotic cells detected by TdT-mediated dUTP nick end labelling significantly increased in MC-cKO at 12 mo compared to age-matched control mice. Taken together, our results suggest that in addition to IOP control, P2Y1 receptor should play an important role in Müller cell function, and that its loss should cause RGC impairment in an IOP-independent mechanism.