A new model of regenerative healing via inflammation-modulating biomaterials

摘要 哺乳动物的组织再生能力仍然难以捉摸。虽然使用干细胞群体 在生物支架的背景下，已经显示出作为替代丢失、损坏或 然而，仍然存在重大挑战。另一种方法是试图唤起一个经典的， 原位再生反应模仿在较低的物种如蝾螈中看到的。虽然这种特性被认为 我们的观察（Heber-Katz）表明，MRL小鼠和相关品系在进化过程中丢失， 显著的自发再生能力证明了该特性在哺乳动物中得以保留。研究 在过去的近20年里，HIF-1α（缺氧诱导因子）的鉴定达到了高潮。 作为调节小鼠再生的中枢因子。HIF-1α在早期的乳腺癌中显著升高， 在MRL小鼠的伤口愈合阶段和用si-RNA抑制HIF-1α完全阻断再生。当 我们在没有再生能力的瑞士韦伯斯特小鼠中模拟了HIF-1α的反应， 被赋予了与正常组织难以区分的组织结构的忠实替换。这 使用PHD抑制剂1，4-DPCA在新型生物材料构建体（Messersmith）中实现， 稳定体内高水平的HIF-1α。在目前的提案中，我们提供了初步结果 这表明在结扎诱导的牙周病小鼠模型中也观察到了令人印象深刻的愈合， 细菌积累导致炎性宿主反应和骨丢失（Hajishengallis模型）。我们 显示骨骼恢复，牙周韧带（PDL）恢复， 在牙髓和牙周组织中发现了反应。我们将使用先进的分子设计， 生产能够实现单剂量和局部递送的生物材料，而不是目前的三剂量递送 系统除了产生一种新的软组织和骨组织再生疗法外，我们认为该系统 提供了一个令人印象深刻的现象景观，将产生重要的机械信息， 口腔组织的原位再生反应。 在目标1中，我们将创造新的生物材料，以延长药物释放，提供单剂量治疗 快速降解的凝胶;在目标2中，我们将检查药物制剂的效果，无论是原始的还是新的， 使用microCT和分子分析对骨和PDL损失和再生进行研究;在目标3中，我们将进一步探索 调节HIF水平后的代谢反应;在目标4中，我们将确定机制因素 参与炎症、整体免疫和干细胞反应。 总之，成功的原位药物诱导再生治疗将显著促进肿瘤的生长。 牙周病的治疗超越了目前的外科手术。

Abstract The ability to regenerate tissue in mammals has remained elusive. While the use of stem cell populations in the context of bio-scaffolds has shown promise as a potential means of replacing lost, damaged, or diseased tissue, significant challenges remain. An alternative approach is to attempt to evoke a classical in situ regenerative response emulating that seen in lower species such as newts. While this trait was thought to be lost in evolution, our observation (Heber-Katz) that the MRL mouse and related strains have a significant spontaneous regenerative capability demonstrates that the trait is retained in mammals. Studies over the past almost 20 years have culminated in the identification of the HIF-1α (hypoxia inducible factor) pathway as the central actor regulating regeneration in mice. HIF-1α is significantly elevated during the early phases of wound healing in MRL mice and inhibiting HIF-1α with si-RNA blocks regeneration entirely. When we mimicked this HIF-1α response in otherwise non-regenerating Swiss Webster mice the regeneration trait was conferred with the faithful replacement of tissue architecture indistinguishable from normal tissue. This was achieved using the PHD inhibitor 1,4-DPCA in a novel biomaterial construct (Messersmith) leading to the stabilization of high levels of HIF-1α in vivo. In this current proposal, we provide preliminary results suggesting that impressive healing is also seen in a mouse model of periodontal disease, ligature-induced bacterial accumulation leading to an inflammatory host response with bone loss (Hajishengallis model). We show that bone recovers, the periodontal ligament (PDL) is restored, and an unusually robust stem cell response in the tooth pulp and in periodontal tissue is found. We will use advanced molecular design to produce a biomaterial capable of achieving single dose and local delivery vs. the current three-dose delivery system. In addition to yielding a novel soft and bone tissue regeneration therapy, we believe that this system provides an impressive landscape of phenomena that will yield important mechanistic information about in- situ regenerative responses in oral tissues. In Aim 1, we will create new biomaterials to yield extended drug release to provide a single-dose treatment with rapidly degradable gels; in Aim 2, we will examine the effect of drug preparations, both original and new, on bone and PDL loss and regrowth using microCT and molecular analysis; in Aim 3, we will further explore the metabolic response after modulating HIF levels; and in Aim 4, we will determine mechanistic factors involved in the inflammatory, overall immune, and stem cell responses. In conclusion, a successful in-situ drug-induced regenerative therapy would significantly advance the treatment of periodontal disease beyond current surgical procedures.