Keratinocyte Integrin Crosstalk During Wound Healing

描述（由申请人提供）：表皮角质形成细胞通过恢复表皮屏障和分泌控制包括伤口血管生成在内的多种过程的旁分泌因子，对正常伤口愈合至关重要。在致病性情况下，表皮功能受损导致慢性愈合不足（如糖尿病性溃疡）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，通过整合素可以调节致病性角化细胞的功能。虽然整合素调节增殖、迁移和生长因子信号传导已被证实，但它们在协调创面角化细胞功能中的作用仍是一个谜。此外，虽然正常和伤口角质形成细胞表达整合素a9b1，但在体内，根据解释，整合素a9b1是缺失的，这与先前在体外研究中观察到的结果相混淆。利用基因定义的、病毒转导的、以不同组合表达整合素a3b1和/或a9b1的角化细胞，我们发现a9b1对由a3b1控制的细胞功能和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，我们已经获得了在表皮中以不同组合表达a3b1和/或a9b1的遗传定义小鼠。引人注目的是，表皮中a9b1的缺失增强了伤口收缩和血管生成，这两种功能归因于由a3b1指导的旁分泌信号。基于我们的基础数据，我们假设a9b1抑制来自表皮的a3b1依赖性旁分泌信号，该信号控制伤口愈合和血管生成。我们进一步假设，a9b1介导的a3b1抑制的调控，可能是通过a9b1在伤口愈合的关键阶段的配体依赖性激活，对于促进伤口愈合的表皮功能的适当时空协调至关重要。这一假设将在基因组学、生物信息学、肽生物化学、细胞生物学和定义的遗传小鼠伤口愈合模型的结合下进行三个目标的测试。在本项目结束时，我们将首次分析角质细胞a9b1的功能，确定a3b1和a9b1如何协调调节伤口修复，确定a9b1对a3b1施加交叉抑制调节的分子机制，并验证a9b1靶向肽可用于控制某些表皮伤口愈合功能的概念。在此过程中，我们将开发新的整合素靶向治疗方法的基础，以调节角化细胞功能和伤口结果。

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.