2023 Fiscal Year Final Research Report

Three dimensional ultrastructural analyses of the distribution pattern and dynamics of the interstitial cells in the connective tissues in the mammalian body.

Research Project

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Project/Area Number	20H03290
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 44040:Morphology and anatomical structure-related
Research Institution	Kurume University
Principal Investigator	NAKAMURA Kei-ichiro 久留米大学, 付置研究所, 客員教授 (20172398)
Co-Investigator(Kenkyū-buntansha)	太田啓介久留米大学, 医学部, 教授 (00258401) 平嶋伸悟久留米大学, 医学部, 客員准教授 (70647784) 力丸由起子 (西由起子) 久留米大学, 医学部, 講師 (90368960)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	間質細胞 / 線維芽細胞 / 結合組織・細胞構築 / 組織動態解析 / 三次元微細構造 / FIB/SEM / volume EM / AI-assisted extraction
Outline of Final Research Achievements	We performed three-dimensional fine structural observation using volumeEM techniques (FIB/SEM tomography) to study interstitial cells universally distributed in the connective tissue throughout the body, focusing on the urogenital organs and lymph nodes. We carried out morphological analysis of the shapes, densities, and distribution patterns of these interstitial cells. As a result, it was shown that the interstitial cells observed in these organs have an extremely thin and widely undulating sheet-like cytoplasm, forming a wide-spread cell network connected by junctions such as gap junctions between adjacent cells. Furthermore, in cultured cells derived from oral fibroblasts, it was shown that the collagen fiber bundles derived from the cells took on a regular arrangement, and this regularity was lost by adding gap junction inhibitors. It was also demonstrated that the AI-assisted automatic extraction of specific structures is useful in such serial electron microscope image analysis.
Free Research Field	医歯薬学・基礎医学・解剖学一般（含組織学・発生学）7901-2（11）組織学
Academic Significance and Societal Importance of the Research Achievements	本課題で開発された三次元微細構造解析法は、結合組織に普遍的に存在する間質細胞の、広範に拡がる細胞ネットワーク形成、組織区画化、組織幹細胞ニッチ、exosomeによるシグナル伝達等の理解に重要な情報を提供した。技術革新とともに、今後、様々な臓器・器官の結合組織細胞の再評価に繋がる成果は学術的に意義深い。また、身体の成長・再生・老化における結合組織の再生医学的役割、また、癌転移、線維化等重要な病態への関わりの観察からは生体構造の生理病態理解が期待され、更には、全身の結合組織における間質細胞の分布密度の偏りの多様性は、臨床的に注目されている筋膜リリースや経絡・経穴の理解の基盤となることも期待される。