Critical role of collagen XII in cell- and matrix-mediated mechanisms regulating acquisition of tendon structure and function in development and the injury response

XII 型胶原蛋白在细胞和基质介导机制中的关键作用，调节肌腱结构和功能在发育和损伤反应中的获得

• 批准号: 10179664
• 负责人: LOUIS J SOSLOWSKY
• 金额: $ 34.9万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-20 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10179664
• 关键词: 3-Dimensional; Cell Communication; Cells; Collagen; Collagen Fiber; Collagen Fibril; Communication; Confounding Factors (Epidemiology); Cre driver; Data; Deposition; Development; Disease; Embryo; Embryonic Development; Exhibits; Extracellular Matrix; Fiber; Fibril-Associated Collagens; Fibroblasts; Future; Gap Junctions; Gel; Goals; Growth; Growth and Development function; Impaired healing; Impairment; Injury; Knock-out; Knockout Mice; Knowledge; Measures; Mechanics; Mediating; Outcome; Pattern; Phase; Play; Population; Positioning Attribute; Process; Role; Shapes; Smooth Muscle Actin Staining Method; Structure; Tendon Injuries; Tendon structure; Testing; Time; Tissues; cell behavior; flexibility; healing; improved; in vivo; innovation; intercellular communication; knock-down; model development; mouse model; nanoscale; new therapeutic target; novel; postnatal; postnatal development; progenitor; repaired; response; response to injury; spatiotemporal; tendon development

Establishment of tendon hierarchical structure is critical to mechanical function. This tightly controlled process requires coordinated cell-cell and cell-matrix communication. During embryogenesis, tendon progenitors organize into linear arrays and establish cell-cell communication prior to assembling ECM, suggesting that cells dictate ECM organization. Cells also clonally expand within linear arrays, suggesting that the ECM also dictates cell organization. Collagen XII is known to regulate collagen fibril assembly by forming bridges between fibrils, and our recent data show that collagen XII-deficient tendons exhibit reduced fibril packing and loss of distinct fiber domains. Interestingly, we also found that these tendons have disordered tenocyte arrangement and gap junction organization, indicating a novel role for collagen XII in cell organization, cell communication, and establishing an organized tenocyte network. However, the extent to which disrupted tendon hierarchical structure due to collagen XII deficiency is driven by disordered cellular arrangement and communication or by the deposition of disorganized ECM remains unelucidated. Therefore, our overarching goal is to establish the temporal roles of collagen XII in regulating tendon cell organization, hierarchical structure, and mechanical function during tendon development and healing. Our global hypothesis is that, in addition to ECM fibril assembly, collagen XII regulates cellular arrangement and communication prior to ECM deposition during development and healing, which is pivotal to establishing normal tendon structure-function. We will use novel tissue-targeted and inducible Col12a1 knockout mouse models to specifically target tendons during development and healing. These mouse models will be used in conjunction with an innovative multiscale approach to assess tissue level mechanics, cell organization and communication, fiber alignment, and fibril size/organization. Aim 1 will define the temporal roles of collagen XII in regulating cell arrangement and ECM assembly during tendon growth and development. Targeted knockdown of Col12a1 will be induced throughout tendon development (Scx-Cre driver; Aim 1a) or following establishment of cell organization (Scx- CreERT2 driver; Aim 1b). Temporal studies will also be conducted using 3D cell-gel constructs to evaluate tissue formation without confounding variables found in vivo. Aim 2 will define the temporal roles of collagen XII in regulating cell arrangement and ECM assembly during tendon healing. Using the SMA-CreERT2 driver, Col12a1 knockdown will be targeted to peritenon-derived progenitors, the primary contributors to healing tendon following injury. In Aim 2a, SMA-expressing cells will be targeted during the proliferative phase, while in Aim 2b, SMA-expressing cells will be targeted at the end of the proliferative phase to isolate contributions to ECM assembly. We will utilize sophisticated and rigorous measures of hierarchical structure/function to define the interplay between cell and ECM assembly in tendon formation through establishment of temporal roles for collagen XII in these processes. These innovative studies will provide guidance for future therapies.

肌腱层次结构的建立对于机械功能至关重要。这个严格控制的过程 需要协调的细胞 - 细胞和电池通信。在胚胎发生期间，肌腱祖细胞 在组装ECM之前组织成线性阵列并建立细胞电池通信，表明 细胞决定ECM组织。细胞还在线性阵列内延伸，表明ECM也 决定细胞组织。已知胶原蛋白XII通过形成桥梁来调节胶原原纤维组件 在原纤维之间，我们最近的数据表明，胶原蛋白缺陷肌腱暴露了纤维填料和 丧失不同的纤维结构域。有趣的是，我们还发现这些肌腱有无序的Tenocyte 布置和间隙连接组织，表明胶原蛋白XII在细胞组织中的新作用，细胞 沟通并建立有组织的Tenocyte网络。但是，破坏的程度 胶原蛋白XII缺乏引起的肌腱层次结构是由细胞排列障碍和 通信或通过混乱的ECM的沉积仍然没有核定。因此，我们的总体 目标是确定胶原蛋白XII在调节腱细胞组织中的临时作用 肌腱发育和愈合过程中的结构和机械功能。我们的全球假设是，在 除ECM原纤维组件外，胶原蛋白XII调节ECM之前的细胞排列和通信 发育和愈合过程中的沉积是建立正常肌腱结构功能的关键。 我们将使用新颖的组织靶向和诱导的COL12A1敲除小鼠模型来专门针对肌腱 在开发和康复期间。这些鼠标模型将与创新一起使用 评估组织水平力学，细胞组织和沟通，纤维对齐方式的多尺度方法， 和原纤维尺寸/组织。 AIM 1将定义胶原蛋白XII在调节细胞排列中的暂时作用 在肌腱生长和发育过程中，ECM组装。 Col12a1的目标敲低将被诱导 通过肌腱发育（SCX-CRE驱动器； AIM 1A）或建立细胞组织后（SCX- creert2驱动程序；目标1b）。时间研究还将使用3D细胞凝胶构建体进行评估 组织形成没有混淆体内发现的变量。 AIM 2将定义胶原蛋白XII的暂时作用 在控制细胞排列和肌腱愈合过程中的ECM组装中。使用SMA-CREERT2驱动程序， COL12A1敲低将针对腹膜衍生的祖细胞，这是治愈的主要因素 受伤后肌腱。在AIM 2A中，在增殖阶段将针对表达SMA的细胞，而 在AIM 2B中，将在增殖阶段的结束时针对表达SMA的细胞以分离贡献 到ECM组装。我们将利用层次结构/功能的复杂和严格的衡量标准 通过建立临时性来定义肌腱形成中细胞和ECM组装之间的相互作用 胶原蛋白在这些过程中的作用。这些创新的研究将为未来的疗法提供指导。