Regenerative wound healing via inflammation-modulating biomaterials

描述（由申请方提供）：众所周知，长期炎症会阻碍伤口修复的最佳目标，即伤口迅速闭合，瘢痕形成最少。然而，组织再生（与伤口修复相反）的目的是重建受损的组织，并用功能性生物复制品替代丢失的组织，而不会留下疤痕。在后一种情况下，炎症的作用还没有很好地确定，原因很简单，大多数哺乳动物，包括人类，很少表现出任何再生能力（肝脏除外），排除了实验方法。基于我们在小鼠附件损伤模型中的初步观察，该提议将解决增强炎症的至少某些方面将重新引导伤口愈合朝向再生的可能性。我们还将研究使用新型生物材料来局部利用炎症反应的关键方面并促进组织再生。 如在兔和近交系MRL小鼠品系中所见，耳全闭合被认为是与两栖动物中的肢体再生类似的哺乳动物再生实例。耳孔完全关闭与软骨的替代和没有疤痕。在该提案中，我们提出了体外和原位证据，表明在这种再生反应期间的伤口部位是促炎性的，并且炎症的药理学上调剂在其他非再生能力小鼠中诱导再生。炎症已被证明是由转录因子HIF 1a调节，我们将集中在HIF 1a上调C57 BL/6小鼠，以进一步探讨其在再生反应中的作用。 由于HIF 1a在蛋白质水平上受到调节，并且其降解是通过脯氨酰羟化酶（PHD）完成的羟基化来启动的，因此我们将研究HIF 1a降解的几种抑制剂，包括PHD抑制剂，直接HIF 1a羟基化抑制剂和泛素化抑制剂。将在HIF-荧光素酶报告基因小鼠及其细胞中筛选这些分子的体外活性，作为1）局部药物或可溶性注射剂进入伤口部位或全身给药，以及2）与生物材料偶联。考虑到HIF活性调节多达10%的所有细胞功能，特别是代谢状态和炎症，重要的是HIF激活药物仅存在于伤口部位并以受控的方式存在。将设计新型原位形成的大分子生物材料，其目标是在空间和时间上精细控制伤口部位的HIF水平。我们设想，这种模拟愈合伤口的复杂组织微环境的方法将允许伴随组织再生的生物材料降解，从而在未来导致新的组织再生临床模式。

DESCRIPTION (provided by applicant): It is well known that prolonged inflammation hinders the optimal goal of wound repair, namely prompt closure of the wound with minimal scarring. However, the objective of tissue regeneration (as opposed to wound repair) is to reconstitute and replace damaged tissue with a functional biological replica of the lost tissue without scarring. In this latter case, the role of inflammation is not well established for the simple reason that most mammals including humans have rarely demonstrated any capacity for regeneration (with the exception of the liver) precluding experimental approaches. Based upon our preliminary observations in a mouse model of appendage injury, this proposal will address the possibility that enhancing at least some aspects of inflammation will re-direct wound healing towards regeneration. We will also examine the use of novel biomaterials to locally harness key aspects of the inflammatory response and facilitate tissue regeneration. Ear whole closure, as seen in rabbits and in the inbred MRL mouse strain is considered to be a mammalian example of regeneration similar to limb regeneration in amphibians. Ear holes close completely with the replacement of cartilage and without scarring. In this proposal, we present in-vitro and in-situ evidence that the wound site during this regenerative response is pro-inflammatory and that pharmacological up- regulators of inflammation induce regeneration in otherwise non-regeneration competent mice. Inflammation has been shown to be regulated by the transcription factor HIF1a and we will focus on HIF1a up-regulation in C57BL/6 mice to further explore its role in the regenerative response. Since HIF1a is modulated at the protein level and its degradation is initiated by hydroxylation accomplished by prolyl hydroxylases (PHDs), we will examine several inhibitors of HIF1a degradation including a PHD inhibitor, a direct HIF1a hydroxylation inhibitor and an inhibitor of ubiquination. These molecules will be screened for activity in HIF-luciferase reporter mice and their cells in-vitro as 1) topical agents or soluble injectants into the wound site or administered systemically and 2) coupled to a biomaterial. Given that HIF activity regulates as much as 10% of all cellular functions and especially the metabolic state and inflammation, it is important that HIF-activating drugs be present only at the wound site and in a controlled manner. Novel in- situ forming macromolecular biomaterials will be designed with the goal of fine control, both spatial and temporal, of HIF levels at the wound site. We envision that this approach of mimicking the complex tissue microenvironment of a healing wound will allow for biomaterial degradation accompanied by tissue regeneration, leading in the future to new clinical modalities for tissue regeneration.