Keratinocyte Integrin Crosstalk During Wound Healing

描述(申请人提供)：表皮角质形成细胞通过重建表皮屏障和分泌旁分泌因子对正常伤口愈合至关重要，这些旁分泌因子控制着包括伤口血管生成在内的各种过程。在致病环境中，表皮功能受损会导致慢性愈合不足(如糖尿病溃疡)或过度愈合(如增生性疤痕)。我们的长期目标是开发治疗范例，通过这些范例可以操纵整合素来调节致病角质形成细胞的功能。虽然整合素调节增殖、迁移和生长因子信号转导已被公认，但它们在协调伤口角质形成细胞功能中的作用仍然是个谜。此外，尽管正常角质形成细胞和创伤角质形成细胞表达整合素a9b1，但在体内，根据解释，整合素a9b1丢失，这与先前研究中在体外进行的观察结果相矛盾。利用基因定义的、病毒转导的角质形成细胞以不同的组合表达整合素a3b1和/或a9b1，我们发现a9b1对细胞功能和由a3b1控制的基因表达具有交叉抑制作用，包括促进内皮细胞功能的旁分泌信号。此外，我们还衍生出了在不同组合的表皮中表达a3b1和/或a9b1的基因定义的小鼠。值得注意的是，从表皮中删除a9b1可以增强伤口收缩和血管生成，这两个功能被归因于a3b1指导的旁分泌信号。根据我们的基础数据，我们假设A9b1抑制控制伤口闭合和血管生成的表皮中依赖A3b1的旁分泌信号。我们进一步假设，对a9b1介导的a3b1抑制的调节，可能是通过在伤口愈合的关键阶段依赖配体激活a9b1，对于促进伤口愈合的表皮功能的适当时空协调至关重要。这一假说将利用基因组学、生物信息学、多肽生物化学、细胞生物学和确定的创伤愈合遗传小鼠模型的组合在三个目标上进行验证。在本项目结束时，我们将首次对角质形成细胞a9b1的功能进行分析，确定a3b1和a9b1如何协调调节伤口修复，确定a9b1对a3b1实施交叉抑制调节的分子机制，并测试a9b1靶向多肽可用于控制某些表皮伤口愈合功能的概念。在此过程中，我们将开发新型整合素靶向治疗药物，以调节角质形成细胞的功能和伤口结局。

DESCRIPTION (provided by applicant): Epidermal keratinocytes are vital to normal wound healing by restoring the epidermal barrier and secreting paracrine factors that govern diverse processes including wound angiogenesis. In pathogenic settings, impaired epidermal function results in chronically insufficient (e.g., diabetic ulcers) or over-exuberant healing (e.g., hypertrophic scars). Our long-term goal is to develop therapeutic paradigms through which integrins can be manipulated to modulate pathogenic keratinocyte function. While it is well established that integrins regulate proliferation, migration and growth factor signaling, their rols in orchestrating wound keratinocyte functions remain enigmatic. Moreover, while normal and wound keratinocytes express integrin a9b1, in vivo, upon explanation integrin a9b1 is lost, confounding observations made in previous studies, in vitro. Using genetically defined, virally transduced keratinocytes that express integrins a3b1 and/or a9b1 in different combinations, we discovered that a9b1 exerts a cross-suppressive effect on cell functions and gene expression that is governed by a3b1, including paracrine signals that promote endothelial cell function. Moreover, we have derived genetically defined mice that express a3b1 and/or a9b1 in epidermis in different combinations. Strikingly, deletion of a9b1 from epidermis enhances wound contraction and angiogenesis, two functions that are attributed to paracrine signaling directed by a3b1. Based on our foundation data, we hypothesize that a9b1 suppresses a3b1-dependent paracrine signals from the epidermis that control wound closure and angiogenesis. We further hypothesize that the regulation of a9b1-mediated suppression of a3b1, perhaps through ligand-dependent activation of a9b1 at key stages of wound healing, is critical for proper temporal and spatial orchestration of epidermal functions that promote wound healing. This hypothesis will be tested in three Aims using a combination of genomics, bioinformatics, peptide biochemistry, cell biology, and defined genetic mouse models of wound healing. At the end of this project period, we will have provided the first analyses of keratinocyte a9b1 functions, determined how a3b1 and a9b1 coordinately regulate wound repair, identified molecular mechanisms through which a9b1 exerts cross- suppressive regulation over a3b1, and tested the concept that a9b1-targeting peptides can be used to control certain epidermal wound healing functions. In doing so, we will have developed the basis for novel integrin- targeting therapeutics to modulate keratinocyte functions and wound outcome.