Regenerative wound healing via inflammation-modulating biomaterials

描述（由申请人提供）：众所周知，持续的炎症会阻碍伤口修复的最佳目标，即以最小的疤痕迅速关闭伤口。然而，组织再生的目标（与伤口修复相反）是重建和替换受损组织，用失去组织的功能生物复制品而不留下疤痕。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，包括人类在内的大多数哺乳动物很少表现出任何再生能力（肝脏除外），这就排除了实验方法。根据我们在小鼠附属物损伤模型中的初步观察，该建议将解决至少在某些方面增强炎症将重新引导伤口愈合走向再生的可能性。我们还将研究使用新型生物材料来局部控制炎症反应的关键方面并促进组织再生。在兔子和近亲繁殖的MRL小鼠品系中所见的全耳闭合被认为是哺乳动物再生的一个例子，类似于两栖动物的肢体再生。耳孔完全闭合与软骨的更换，没有疤痕。在这项提议中，我们提出了体外和原位证据，证明再生反应中的伤口部位是促炎的，炎症的药理学上调调节剂可以诱导非再生能力小鼠的再生。炎症已被证明受转录因子HIF1a的调节，我们将重点关注C57BL/6小鼠中HIF1a的上调，以进一步探索其在再生反应中的作用。由于HIF1a在蛋白质水平上被调节，其降解是由脯氨酸羟化酶（ph）完成的羟基化启动的，我们将研究几种HIF1a降解抑制剂，包括PHD抑制剂，直接HIF1a羟化抑制剂和泛素化抑制剂。这些分子将在hif荧光素酶报告小鼠及其细胞中进行体外活性筛选，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，2)与生物材料偶联。鉴于HIF活性调节了多达10%的所有细胞功能，特别是代谢状态和炎症，因此HIF激活药物仅存在于伤口部位并以可控的方式存在是很重要的。新的原位形成的大分子生物材料将被设计为精细控制的目标，无论是空间和时间，在伤口部位的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生物材料降解伴随着组织再生，从而导致未来组织再生的新临床模式。

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. PUBLIC HEALTH RELEVANCE: Achieving predictable regeneration of damaged tissues and organs is a major goal of medicine. By studying the remarkable ability of the MRL mouse to heal injuries and the role of inflammation in this process, we will gain insight into methods to help translate this knowledge into patient care. In particular, we will examine the role of implantable "smart" biomaterials that release regeneration-specific drugs that regulate metabolism and inflammation and are under biological control.