シンポジウム（Symposium）

Symposium Dynamics and its novel mechanisms of "capillary-milieu" in the CNS development and diseases シンポジウム神経の発生と病態における血管環境ダイナミクスとその制御機構

7月28日（日）8:50～9:12　第6会場（朱鷺メッセ　2F　201A） 4S06m-1 大脳皮質における血管ー神経の協調的な発生制御機構 Ken-ichi Mizutani（水谷健一）神戸学院大院薬 Mammalian neocortical development encompasses an entire set of events that leads to the generation of excitatory and inhibitory neurons from neural progenitors in the dorsal and ventral telencephalon, including cell proliferation, production of migratory precursors and their progeny, differentiation, and integration into circuits. During these processes, the developing neocortex acquires its vasculature by angiogenesis, a process consisting of proliferation of endothelial cells in existing blood vessels or vascular plexuses, and leading to formation of new blood vessels. Based on the anatomical location, growth pattern, and developmental regulation, the telencephalic vasculature has been suggested to comprise of two categories: pial vessels and periventricular vessels. The neural tube, acting as a vessel patterning nexus, directs the formation of the pial vessels that encompass it. The periventricular vessels of the basal ganglia primordium actively develop in the ventral telencephalon and form an elaborate network that progressively propagates into the dorsal telencephalon by E11.5. Recent studies have suggested that neocortical angiogenesis progresses in a spatially and temporally restricted manner to construct a specialized vascular niche that supports ongoing neurogenesis during neocortical development. Here we report that periventricular blood vessels selectively influence neocortical progenitor behavior and neurogenesis, highlighting how CNS angiogenesis is utilized to construct neocortical cytoarchitecture.		7月28日（日）9:12～9:34　第6会場（朱鷺メッセ　2F　201A） 4S06m-2 人工微小血管モデルを用いた血管ダイナミクスの可視化 Yukiko Matsunaga（松永行子）東京大生産研 Inhibiting or normalizing pathological angiogenesis is a therapeutic strategy that has been extensively studied and already brought up clinically with approved drugs. However, most experimental assays for drug development rely on 2D cell culture models, which fail to mimic sprouting from a parent vessel. We have developed a microvessel-on-a-chip which enables the study of drugs targeting a specific pathway of angiogenesis. Microvessels were prepared using human umbilical vein endothelial cells (HUVEC) within a collagen gel scaffold. Sprouting angiogenesis was induced by VEGF-A, and it was shown to depend on the Notch signaling. 3D structure of microvessel model was noninvasively well characterized by optical coherence tomography. To examine the efficacy of angiogenic inhibitors, two types of inhibitors: sorafenib and sunitinib which target the VEGF-A/VEGFR-2 pathway were used. A dose dependency of the angiogenesis inhibition could be observed using both inhibitors. Furthermore, the design of the chip enables the study of microvessel permeability by introducing a fluorescent molecule (FITC-dextran; 70 kDa) in the lumen of the parent vessel. It revealed that sorafenib impaired the endothelial barrier function whereas sunitinib did not. Overall this technology should contribute to improve the discovery of promising anti-angiogenic molecules and provide a convenient tool to assess fundamental questions about mechanisms at an endothelial cellular level during VEGF-A-induced angiogenesis.

7月28日（日）9:34～9:56　第6会場（朱鷺メッセ　2F　201A） 4S06m-3 初期網膜オルガノイドの分子解析 Nozomu Takata（高田望）¹，Fiore Luciano（Luciano Fiore）¹，He Liqun（Liqun He）²，Marc A. Morgan（Morgan A. Marc）³，Manuel JG. Rodriguez（Rodríguez JG. Manuel）⁴，Nikita Joshi（Joshi Nikita）⁵，Alexander V. Misharin（Misharin V. Alexander）⁵，Ryan B. Embry（Embry B. Ryan）⁶，Priyam Patel（Patel Priyam）⁶，Matthew Schipma（Schipma Matthew）⁶，Ali Shilatifard（Shilatifard Ali）³，Christer Betsholtz（Betsholtz Christer）²，Guillermo Oliver（Oliver Guillermo）¹ ¹ノースウェスタン大学 ²Dept Immunology, Genetics and Pathology, Rudbeck Lab, Uppsala Univ, Uppsala, Sweden. ³Dept Biochemistry and Molecular Genetics, Northwestern Univ, Feinberg School of Medicine, Chicago, USA ⁴Spanish National Center for Cardiovascular research, Madrid, Spain ⁵Dept Med and Pulmonary and Critical Care Medicine, Northwestern Univ, Chicago, USA. ⁶Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern Univ, Chicago, USA Neural organoids are stem cell-derived three-dimensional (3-D) tissues that recapitulate most of the in vivo developmental features. Organoids are becoming a powerful tool to study normal development, regeneration, disease modelling and drug screening. Accordingly, a better characterization of the different cell types participating in organoid differentiation and their transcriptional profiling is a valuable asset. In this study, we took advantage of an eye organoid culture system to investigate the earliest steps of optic vesicle (OV) morphogenesis. Using scRNAseq, we identified 15 cell types during this process. Interestingly, a pseudotime analysis revealed time-dependent transcriptional changes, and predicted multiple novel genes that are specifically expressed in different cell clusters in a temporal manner. Furthermore, we cross-referenced the scRNAseq data with data we generated using ChIPseq to identify direct targets of Rax, an essential transcriptional regulator of OV evagination. Similar to in vivo, functional inactivation of Rax in organoids arrested OV formation and expression of some of the identified candidate genes was downregulated. Our finding highlights some of the key cell types participating in neural organoid morphogenesis. These findings might facilitate the understanding of the transition phases from immature to mature organs that are likely dependent on a functional blood vasculature.		7月28日（日）9:56～10:18　第6会場（朱鷺メッセ　2F　201A） 4S06m-4 神経網膜由来レチノイン酸による網膜色素上皮を介した脈絡膜発達制御機構 Akishi Onishi（大西暁士）^1,2 ¹理研BDR 網膜再生医療研究開発プロジェクト ²神戸市立神戸アイセンター病院研究センター患者iPS細胞研究室 The retina is the light-sensitive tissue at the back of the eye that consists of neuronal layers (neural retina) and retinal pigment epithelium (RPE). The choroid is a highly vascularized layer surrounding the retina and supplies nutrients and oxygen to the neural retina via RPE. Impairment of the choroidal vasculature is associated with age-related macular degeneration (AMD), progressive loss of central vision. VEGF secreted from retinal pigment epithelium (RPE) cells plays a pivotal role in the vascular development and maintenance, but the molecular regulatory mechanism of the choroidal vasculature formation has not been clarified despite the clinical importance. We found that aldehyde dehydrogenase 1 family, member A1 knockout (Aldh1a1^-/-) mice showed choroidal hypoplasia with insufficient vascularization in the dorsal region, although Aldh1a1 is expressed in the dorsal neural retina, not in the RPE/choroid complex. We analyzed choroidal vascular development in Aldh1a1^-/- mice and demonstrated that RAs produced by Aldh1a1 in the neural retina directs dorsal choroidal vascular development via Sox9 upregulation in the dorsal RPE cells to enhance RPE-derived VEGF secretion. Also, we found a characteristic lesion of dry type of AMD such as RPE atrophy and photoreceptor degeneration in the aged Aldh1a1^-/- mouse, and further identified differentially regulated genes in the Aldh1a1^-/- eyes before the onset of AMD-like phenotype. Our findings contain novel insights into both the molecular networks of neurovasculature development and into the molecular pathology of AMD progression.

7月28日（日）10:18～10:40　第6会場（朱鷺メッセ　2F　201A） 4S06m-5 血管環境を制御する分子技術と損傷脳再生への応用 Itsuki Ajioka（味岡逸樹）東京医歯大脳統合機能研究セ Ischemic brain stroke is caused by blood flow interruption, leading to focal ischemia, neuron death, and motor, sensory, and/or cognitive dysfunctions. Angiogenesis, neovascularization from existing blood vessel, is essential for tissue growth and repair. Proangiogenic therapy for stroke is promising for preventing excess neuron death and improving functional recovery. Vascular endothelial growth factor (VEGF) is a critical factor for angiogenesis by promoting the proliferation, the survival, and the migration of endothelial cells. Biomaterials generated from ECM components produce cell scaffolding for tissue regeneration. Since some ECM components associate with angiogenic proteins and provide an angiogenic microenvironments, such biomaterials can effectively enhance angiogenesis and tissue regeneration. We previously generated a porous sponge from basement membrane (BM) matrix for the 3D culture of neurons and for a migration scaffold for neuroblasts in the injured cerebral cortex. Among such strategies, affinity-immobilization of VEGF on a porous sponge via C-terminal tag protein is an attractive approach because the covalent immobilization may lose the protein configuration and function. In this symposium, I will introduce such molecular technologies regulating the vascular environment and the application to injured brain regeneration.