Investigate the mechanisms underlying microRNA-146a activity in regulation of foreign body response to biomaterials

项目摘要 植入生物材料和装置通常会导致异物反应(FBR)，这是一种慢性 最终可能导致植入失败的炎症状态，这可能会对患者造成伤害或死亡。 FBR背后的分子机制仍然知之甚少。提高了对分子的理解 FBR产生的潜在机制是开发新的和有效的 消除或减少FBR的治疗策略。巨噬细胞在肿瘤的发生和发展中起中心作用。 联邦调查局。它们参与炎性蛋白的表达，形成破坏性的异物巨人 细胞(FBGCs)、细胞外基质的重塑和植入物的包裹。新兴数据支持 机械信号在巨噬细胞激活中的关键作用，例如基质僵硬。MicroRNAs(MiR)是 内源性、小的、非编码的RNA已经成为许多基因表达的强大调节者 细胞过程包括巨噬细胞激活、细胞融合、炎症和纤维化。特定的功能 MIR在FBR对生物材料的调节中的作用尚不确定；具体地说，基质是否 刚度调节miR的表达以驱动FBR。这些差距对快堆领域的进展构成了重大障碍。 在最近令人兴奋的初步数据中，我们获得了miR-146a可能是FBR对 生物材料。具体地说，我们发现：1)miR-146a在种植体贴壁组织中的表达水平降低 一种与巨噬细胞聚集增加相关的皮下植入模型 2)小鼠的miR-146a缺失加剧了S.C.的FBR过程 3)体内巨噬细胞在组织-种植体界面聚集的严重程度 取决于植入物的硬度；4)基因消融miR-146a增强巨噬细胞黏附和 在僵硬的基质上扩散，巨噬细胞中FBGC的形成和炎症，以及5)基因消融TRPV4，And。 瞬时受体电位香草素家族中的离子通道抑制种植体粘连组织的发育 用原子力显微镜测定快堆下的硬度。进一步的初步数据表明两者之间存在关联 在快堆条件下，基质硬度、miR-146a活性和TRPV4之间的关系。这项建议的目的是 明确miR-146a在FBR中的作用，并阐明其潜在的分子机制。基于我们的 初步数据，我们的中心假设是miR-146a通过调节 巨噬细胞的激活和纤维化的形成依赖于植入物引起的组织僵硬的变化。我们 将通过分子功能增减研究来检验我们的假说。我们期待这项研究的结果 可以提供关于调节FBR的分子机制的宝贵信息和见解 生物材料，这可能导致开发一种新的、有效的基于microRNA的治疗策略 鲜为人知的FBR对生物材料的改进。

Project Summary Implantation of biomaterials and devices often leads to the development of a foreign body response (FBR), a chronic inflammatory condition that can ultimately lead to implant failure, which may cause harm to or death of the patient. The molecular mechanisms underlying the FBR remain poorly understood. Improved understanding of the molecular mechanisms underlying the generation of FBR is the most important step for the development of novel and effective therapeutic strategies that eliminate or reduce the FBR. Macrophages are central to development and progression of the FBR. They participate in the expression of inflammatory proteins, formation of destructive foreign body giant cells (FBGCs), remodeling of the extracellular matrix, and encapsulation of the implant. Emerging data support a critical role for a mechanical signal, e.g., matrix stiffness, in macrophage activation. MicroRNAs (miRs) are endogenous, small, non-coding RNAs that have emerged as powerful regulators of gene expression in numerous cellular processes including macrophage activation, cell fusion, inflammation, and fibrosis. The function of specific miRs in regulation of FBR to biomaterials is uncertain; specifically, it remains an open question whether matrix stiffness regulates miR expression to drive FBR. These gaps pose a significant barrier to progress in the FBR field. In recent, exciting preliminary data, we obtained evidence that miR-146a may be a negative regulator of FBR to biomaterials. Specifically, we found that: 1) miR-146a expression levels decreased in the implant-adhered tissues in a subcutaneous (s.c) implantation model, which correlated with increased macrophage accumulation, FBGC formation, and collagen accumulation; 2) miR-146a deletion in mice exacerbated FBR processes in a s.c implantation model; 3) the severity of the in vivo macrophage accumulation at the tissue-implant interface was dependent on the stiffness of the implant; 4) genetic ablation of miR-146a augmented macrophage adhesion and spreading on stiff matrix, FBGC formation, and inflammation in macrophages, and 5) genetic ablation of TRPV4, an ion channel in the transient receptor potential vanilloid family, inhibited development of implant-adhered tissue stiffness under FBR as determined by Atomic Force Microscopy. Further preliminary data suggested an association between matrix stiffness, miR-146a activity, and TRPV4, under FBR conditions. The objective of this proposal is to define the role of miR-146a in the FBR, and to elucidate the underlying molecular mechanisms. Based on our preliminary data, our central hypothesis is that miR-146a modulates the FBR to biomaterials by regulating macrophage activation and fibrogenesis in a manner dependent on implant-induced change in tissue stiffness. We will test our hypothesis through molecular gain- or loss-of-function studies. We expect that the results of this study may provide invaluable information and insight regarding the molecular mechanisms mediating the FBR to biomaterials, which may lead to the development of a novel and effective microRNA-based therapeutic strategy for the amelioration of the poorly understood FBR to biomaterials.