Thant Lay, Kaku Masaru, Kakihara Yoshito, Mizukoshi Masaru, Kitami Megumi, Arai Moe, Kitami Kohei, Kobayashi Daiki, Yoshida Yutaka, Maeda Takeyasu, Saito Isao, Uoshima Katsumi, Saeki Makio
Division of Dental Pharmacology, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
Division of Orthodontics, Faculty of Dentistry & Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.
Front Physiol. 2022 May 20;13:899699. doi: 10.3389/fphys.2022.899699. eCollection 2022.
The periodontal ligament (PDL) is a specialized connective tissue that provides structural support to the tooth and is crucial for oral functions. The mechanical properties of the PDL are mainly derived from the tissue-specific composition and structural characteristics of the extracellular matrix (ECM). The ECM also plays key roles in determining cell fate in the cellular microenvironment thus crucial in the PDL tissue homeostasis. In the present study, we determined the comprehensive ECM profile of mouse molar PDL using laser microdissection and mass spectrometry-based proteomic analysis with ECM-oriented data curation. Additionally, we evaluated changes in the ECM proteome under mechanical loading using a mouse orthodontic tooth movement (OTM) model and analyzed potential regulatory networks using a bioinformatics approach. Proteomic changes were evaluated in reference to the novel second harmonic generation (SHG)-based fiber characterization. Our ECM-oriented proteomics approach succeeded in illustrating the comprehensive ECM profile of the mouse molar PDL. We revealed the presence of type II collagen in PDL, possibly associated with the load-bearing function upon occlusal force. Mechanical loading induced unique architectural changes in collagen fibers along with dynamic compositional changes in the matrisome profile, particularly involving ECM glycoproteins and matrisome-associated proteins. We identified several unique matrisome proteins which responded to the different modes of mechanical loading in PDL. Notably, the proportion of type VI collagen significantly increased at the mesial side, contributing to collagen fibrogenesis. On the other hand, type XII collagen increased at the PDL-cementum boundary of the distal side. Furthermore, a multifaceted bioinformatics approach illustrated the potential molecular cues, including PDGF signaling, that maintain ECM homeostasis under mechanical loading. Our findings provide fundamental insights into the molecular network underlying ECM homeostasis in PDL, which is vital for clinical diagnosis and development of biomimetic tissue-regeneration strategies.
牙周韧带（PDL）是一种特殊的结缔组织，为牙齿提供结构支持，对口腔功能至关重要。PDL的力学性能主要源于细胞外基质（ECM）的组织特异性组成和结构特征。ECM在决定细胞微环境中的细胞命运方面也起着关键作用，因此对PDL组织稳态至关重要。在本研究中，我们使用激光显微切割和基于质谱的蛋白质组学分析，并结合以ECM为导向的数据管理，确定了小鼠磨牙PDL的综合ECM谱。此外，我们使用小鼠正畸牙齿移动（OTM）模型评估了机械加载下ECM蛋白质组的变化，并使用生物信息学方法分析了潜在的调控网络。参照基于新型二次谐波产生（SHG）的纤维表征评估蛋白质组变化。我们以ECM为导向的蛋白质组学方法成功地阐明了小鼠磨牙PDL的综合ECM谱。我们揭示了PDL中存在II型胶原蛋白，这可能与咬合力下的承重功能有关。机械加载诱导了胶原纤维独特的结构变化以及基质组谱的动态组成变化，特别是涉及ECM糖蛋白和基质组相关蛋白。我们鉴定了几种独特的基质组蛋白，它们对PDL中不同模式的机械加载有反应。值得注意的是，VI型胶原蛋白的比例在近中侧显著增加，有助于胶原纤维生成。另一方面，XII型胶原蛋白在远中侧的PDL-牙骨质边界处增加。此外，多方面的生物信息学方法阐明了潜在的分子线索，包括PDGF信号传导，其在机械加载下维持ECM稳态。我们的研究结果为PDL中ECM稳态的分子网络提供了基本见解，这对临床诊断和仿生组织再生策略的开发至关重要。
