記述言語：英語   掲載種別：研究論文（学術雑誌）  

The periodontal ligament (PDL) is a specialized connective tissue crucial for tooth support and periodontal health. Laminins, key components of the extracellular matrix (ECM), mediate cellular behaviors by interacting with integrins, thereby influencing tissue homeostasis and regeneration. This study aimed to identify the predominant laminin isoform in periodontal ligament cells (PDLCs) and elucidate its functions. Using a trans-omics approach integrating transcriptomic and proteomic data, laminin 411, composed of α4, β1, and γ1 chains, was identified as the predominant isoform in cultured mouse PDLCs, a finding conserved in human PDLCs. In contrast, in native mouse PDL tissues, laminin 332 was predominantly localized at the PDL-cementum boundary, whereas laminin-411/421 was ubiquitously distributed throughout the PDL, with partial localization to endothelial cells. These findings highlight the site-specific localization of laminin isoforms within the native PDL tissue. Functional analyses using a recombinant laminin 411 E8 fragment (LM411-E8), which retained integrin-binding capacity, demonstrated a significant enhancement of PDLC adhesion and proliferation. Neutralizing antibody assays revealed integrin α6β1 to be the primary mediator of these responses. Notably, LM411-E8 exerted minimal effects on osteoblastic or fibroblastic differentiation, suggesting its primary role in maintaining the PDLC phenotype rather than in promoting lineage commitment. These findings highlight laminin 411 as a critical regulator of PDLC behaviors and indicate its potential for cell type-dependent periodontal tissue engineering applications. This study provides foundational insights into ECM-PDLC regulatory mechanisms, facilitating the future development of targeted regenerative therapies and biomimetic scaffolds aimed at effective periodontal regeneration.

DOI： 10.1016/j.bbrc.2025.153077

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The extracellular matrix (ECM) plays a crucial role in tissue structure and function and serves as an integral component of diverse biological systems. However, the comprehensive characterization of ECM components is challenging because of the insoluble nature of highly cross-linked and glycosylated ECM proteins. This study introduces a chemical digestion-assisted proteomic approach to overcome challenges in ECM profiling, offering an in-depth analysis of the human periodontal ligament (PDL), a tissue critical for oral function and regeneration. Furthermore, we investigated alterations in the ECM composition of cultured PDL cells to provide insights relevant to tissue engineering applications. Our protocol combined chemical digestion and deglycosylation to enhance the identification of ECM proteins. Chemical digestion by hydroxylamine improved protein extraction efficiency by approximately two-fold compared to conventional chaotropic extraction, and deglycosylation increased the number of identified ECM proteins without substantially altering the ECM profile, offering robust quantification of ECM components. A sequential protein extraction approach revealed that proteins insoluble by conventional methods are primarily composed of highly cross-linked fibrillar collagen. Through the application of this technique to human PDL tissue, we present a comprehensive ECM profile for the first time, revealing a high collagen content (> 80%) and identifying dominant non-collagenous ECM proteins, such as periostin, dermatopontin, and lumican. Our findings highlight the significant differences between the native ECM of PDL tissue and that produced by cultured PDL cells, emphasizing the importance of considering these variations in regenerative strategies. This study offers a robust tool for analyzing the ECM and its dynamics across diverse tissues and under various physiological and pathological conditions. The results enhance our understanding of periodontal tissue and will inform future approaches for periodontal tissue regeneration.

DOI： 10.1016/j.mcpro.2025.101460

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担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

Regeneration of periodontal tissue, particularly the cementum-periodontal ligament (PDL)-bone complex, has long been challenging because the differentiation kinetics of cells and the molecular pathways contributing to the regeneration process are largely unknown. We aimed to evaluate the cell behavior and molecular pathways that contribute to periodontal tissue regeneration in vivo. We analyzed the process of periodontal tissue regeneration through subrenal capsule transplantation of immediately extracted molars in mice. We showed that the regenerated periodontal tissue in the subrenal capsule was morphologically comparable to the intact periodontal tissue, with increased cellular cementum thickness in the apical region. Cell tracing analysis revealed that the cells comprising the regenerated periodontal tissue were derived from transplanted teeth and were indispensable for periodontal tissue regeneration, whereas recipient mouse-derived cells partly contributed to angiogenesis. Bioinformatics analysis based on the gene expression profile in the transplanted teeth indicated that Wnt/β-catenin signaling is involved in periodontal tissue regeneration, which was further confirmed through β-catenin immunohistochemistry. Moreover, the constitutive activation of β-catenin in the cells of transplanted teeth was found to promote accelerated cellular cementum apposition, while the conditional knockout of β-catenin in the cells of transplanted teeth suppressed cellular cementum apposition. Notably, the manipulation of Wnt/β-catenin signaling did not interfere with the bone-PDL-cementum complex, while endogenous osteoclast activity was affected in bone. Our results demonstrated the essential roles of endogenous PDL cells in periodontal tissue regeneration and that Wnt/β-catenin signaling is involved in this process, particularly cellular cementum apposition. Hence, controlling this pathway could promote cementum regeneration, which is a critical process for the regeneration of the cementum-PDL-bone complex. This study provides novel insights into cell behavior and signaling pathways that will advance practical periodontal tissue regeneration.

DOI： 10.1177/00220345241286490

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The cementum is a highly mineralized tissue that covers the tooth root. The regional differences among the types of cementum, especially in the extrinsic fibers that contribute to tooth support, remain controversial. Therefore, this study used second harmonic generation imaging in conjunction with automated collagen extraction and image analysis algorithms to facilitate the quantitative examination of the fiber characteristics and the changes occurring in these fibers over time. Acellular extrinsic fiber cementum (AEFC) was invariably observed in the superficial layer of the apical cementum in mouse molars, indicating that this region of the cementum plays a crucial role in supporting the tooth. The apical AEFC exhibited continuity and fiber characteristics comparable with the cervical AEFC, suggesting a common cellular origin for their formation. The cellular intrinsic fiber cementum present in the inner layer of the apical cementum showed consistent growth in the apical direction without layering. This study highlights the dynamic nature of the cementum in mouse molars and underscores the requirement for re-examining its structure and roles. The findings of the present study elucidate the morphophysiological features of cementum and have broader implications for the maintenance of periodontal tissue health.

DOI： 10.1369/00221554241229130

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記述言語：英語   掲載種別：研究論文（学術雑誌）  

The periodontal ligament (PDL) is a critical component in maintaining tooth stability. It is composed of cells and an extracellular matrix (ECM), each with unique roles in tissue function and homeostasis. Secreted protein acidic and rich in cysteine (SPARC), a calcium-binding matricellular glycoprotein, plays a crucial role in regulating ECM assembly and turnover, alongside facilitating cellular-ECM interactions. In the present study, mass spectrometry-based proteomics was used to assess the impacts of Sparc-knockout (KO) on PDL-derived cells. Results demonstrated that Sparc-KO significantly reduces ECM production and alters its composition with increased levels of type I collagen. Despite this increase in Sparc-KO, type I collagen was not likely to be effectively integrated into the fibrils due to collagen cross-linking impairment. Furthermore, the pathway and process enrichment analyses suggested that SPARC plays a protective role against ECM degradation by antagonistically interacting with cell-surface collagen receptors. These findings provide detailed insights into the multifaceted role of SPARC in ECM organization, including its impact on ECM production, collagen regulation, and interactions with various cellular compartments. A better understanding of these complex mechanisms is crucial for comprehending the causes of periodontal disease and tissue regeneration, where precise control of ECM organization is necessary.

DOI： 10.1016/j.bbrc.2023.149364

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J-GLOBAL

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