EGFR-MEDIATED CORNEAL EPITHELIAL WOUND HEALING

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 表皮生长因子受体（EGFR）活性调节角膜上皮伤口愈合和稳态。 角膜上皮细胞中EGFR的刺激诱导与角膜上皮伤口愈合相关的三种细胞变化：细胞迁移、增殖和分层。通过小分子抑制剂或阻断抗体抑制配体刺激的EGFR活化，导致所有三种细胞变化减少以及伤口愈合受损。尽管有证据表明表皮生长因子受体是必要的和足够的角膜上皮稳态和伤口愈合，表皮生长因子具有有限的治疗效用。 我们假设EGFR的脱敏限制了EGF配体的治疗用途。 脱敏通过配体：受体复合物经由网格蛋白包被的囊泡内化到细胞中而发生。 该复合物通过早期和晚期内体的内吞途径运输，并以复合物的溶酶体降解达到高潮。 我们已经确定了转化生长因子-α（TGF-α）作为一种配体，改变了路线的内吞运输的配体：受体复合物。 用TGF-α治疗促进配体：受体复合物的内化，但不是将其靶向溶酶体，而是促进受体再循环至质膜。 因此，EGFR可以发出更长时间的信号。 增强的信号传导的生理结果是角膜上皮细胞迁移的增加。 由于尚不清楚细胞迁移的增加是由于EGFR信号传导的持续时间还是信号传导的空间位置，未来的研究将在离散的内吞阶段破坏内吞运输，目的是进行这种区分。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Corneal epithelial wound healing and homeostasis is regulated by Epidermal Growth Factor Receptor (EGFR) activity. Stimulation of the EGFR in corneal epithelial cells induces the three cellular changes associated with corneal epithelial wound healing: cell migration, proliferation, and stratification. Inhibition of ligand-stimulated EGFR activation, either through small molecule inhibitors or blocking antibodies, results in a decrease in all three cellular changes as well as impaired wound healing. Despite evidence that the EGFR is necessary and sufficient for corneal epithelial homeostasis and wound healing, EGF has limited therapeutic utility. We hypothesize that desensitization of the EGFR limits the therapeutic use of EGF ligands. Desensitization occurs through internalization of the ligand:receptor complex via clathrin-coated vesicles into the cell. This complex traffics through the endocytic pathway through early and late endosomes and culminates with the lysosomal degradation of the complex. We have identified transforming growth factor-alpha (TGF-alpha) as a ligand that alters the itinerary of endocytic trafficking of the ligand:receptor complex. Treatment with TGF-alpha promotes internalization of the ligand:receptor complex, but rather than targeting it to the lysosome, promotes receptor recycling to the plasma membrane. As a result, the EGFR can signal for longer. The physiological consequence of enhanced signaling is an increase in corneal epithelial cell migration. Since it is not clear if the increase in cell migration is due to the duration of EGFR signaling or the spatial placement of signaling, future studies will disrupt endocytic trafficking at discrete endocytic stages with the goal of making this distinction.