PPARγ诱导M2巨噬细胞替代激活对利用异种TDM构建生物牙根的免疫调控相关研究

Tissue or organ regeneration using xenogeneic scaffold is a promising approach to address the shortage of donor for allotransplantation, however, it is usually compromised by the host response or potential foreign body responses and results in failure. Activation of PPARγ, a ligand-activated transcription factor, could not only modulate inflammation but also augment alternative macrophage polarization that paly pivotal role in tissue repair. Our previous studies have successfully regenerated bio-root with occlusion function by allogeneic dentin derived material (TDM). Our further study have constructed xenogeneic bio-root via xenogeneic TDM, and found the scaffold and surrounding alveolar bone absorbing with abnomal pulp tissue and periodontal tissue reconstruction and macrophage polarization from M1 to M2 during the regeneration progress. But its relevant mechanism is still not clear. Based on our and other previous studies, using the rat, miniature pig, and monkey models, the present study focus on exploring immunomodulatory effect of xenogeneic TDM scaffold in bio-roots construction by discovering the function of PPARγ that regulates the key signaling pathways and augmenting alternative M2 macrophage polarization to which promote the tissue regeneration. This study expects to identify PPARγ activation modifying xenogeneic TDM to construct the bio-root as a potent facilitator of xenogeneic matrix reconstruction in a model of xenogeneic bio-engineered tooth root reconstruction. The significance of our project is not only to establish the theoretical and biotechnology foundation for bio-root construction and its clinic application, but also to provide theoretical guidance for the clinical translation of xenogeneic matrix-based regenerative medicine.

利用异种生物支架构建组织工程器官能有效解决组织器官移植供体来源有限难题，但常引发宿主免疫排斥，导致失败。PPARγ，一种配体激活转录因子，不仅能有效调控炎症，且可加速替代巨噬细胞极化，促进组织再生。本团队利用同种异体牙本质基质（TDM）成功再生具有咬合功能的生物牙根，并发现利用异种TDM构建生物牙根过程中，生物支架及周围牙槽骨吸收，牙髓与牙周组织形成异常，巨噬细胞发生极化，M1型向M2型转化，但其相关免疫调控机制不清。本项目拟在前期研究基础上，以大鼠、小型猪及猕猴为动物模型，结合PPARγ干扰关键信号通路调控免疫反应，诱导M2巨噬细胞极化，促进组织再生，探讨其对基于异种TDM生物构建生物牙根过程中的免疫调控作用，探索PPARγ激活剂修饰异种TDM生物支架构建生物牙根的再生策略，其意义在于为生物牙根构建及其临床应用奠定理论及生物技术基础，为利用异种生物支架构建组织工程器官相关研究提供借鉴。

利用异种生物支架构建组织工程器官能有效解决组织器官移植供体来源有限难题，但常引发宿主免疫排斥，导致失败。PPARγ，一种配体激活转录因子，不仅能有效调控炎症，且可加速替代巨噬细胞极化，促进组织再生。本项目组使用xTDM-aDFCSs 构建生物牙根，明确了其在宿主体内可能引起的免疫应答，并阐明异种生物牙根对免疫细胞的影响，揭示应用 xTDM-aDFCSs 进行生物牙根构建时诱发免疫反应机制。研究生物牙根构建对巨噬细胞激活的影响，探索巨噬细胞替代激活对生物牙根构建的免疫调控。探索 PPARγ激动剂替代激活巨噬细胞的分子水平机制，揭示 PPARγ替代激活巨噬细胞对生物牙根构建的免疫调控机制，并进一步探究Notch通路抑制剂DAPT调节巨噬细胞的极化和功能，减弱异种生物牙根植入后的免疫炎症反应，为基于 xTDM 构建生物牙根的免疫调控提供理论依据，寻求减少宿主对xTDM-aDFCSs 免疫排斥的调控手段，为组织器官再生策略提供了理论和实验依据。 在项目的执行过程中，为进一步提高生物牙根移植成功率，我们同时探究了TDM搭载TGF-β1/BMP4 对生物牙根颈部封闭的作用，提高生物牙根植入后的稳定性;探究Hertwig上皮根鞘细胞与DFCs相互作用，促进生物牙根的牙周再生；基于有限元分析的后牙应力分析优化生物牙根的多根种植设计，并进一步利用TDM颗粒3D打印构建个性化多形态的生物牙根，为生物牙根临床应用策略提供重要的技术保障及基础。

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