Maintenance of Ocular Surface Integrity

描述（申请人提供）：关于维持眼表健康所需的上皮细胞增殖和细胞分化之间平衡的协调机制知之甚少。在过去的资助期内，该项目侧重于基质金属蛋白酶（MMP）明胶酶B （gelB; MMP-9）的作用，其表达在角膜上皮前部被诱导迁移到伤口表面。这一新发现表明gelB调节再生上皮的增殖平衡。敲除小鼠的GelB缺乏加速了再生上皮细胞的增殖，与细胞因子il -1 α的过早积累有关。相反，研究人员发现，在没有任何其他输入的情况下，IL-1不会刺激gelB的表达。这与它对其他MMPs表达的影响不同，需要进一步了解。GelB缺乏还与再生上皮中Smad2转录因子激活的延迟有关，这提示了增强增殖率的机制。另一个新发现是转录因子Pax-6以正、负两种方式控制GelB启动子，并在角膜上皮的迁移前沿与GelB一起被诱导。初步数据表明Pax-6缺乏与gelB缺乏对眼球表面重塑的影响相似。这项新提案建立在上一个资助期开发的概念框架上，扩展了研究，以回答新发现提出的一些问题。一个新的重点将是通过表皮生长因子受体（EGFR）的信号传导，以及由角膜神经激活的G蛋白偶联受体（gpcr）对其的调节。本研究将解决以下问题：1)是什么控制了伤口环境中gelB的表达，角膜神经能否改变IL-1控制gelB表达的能力？2) gelB如何控制il - α的表达，il -1 α是否影响上皮的迁移或增殖？如果是这样，这能解释gelb缺陷表型吗？3) gelB如何控制Smad2的活性以及神经如何相互作用？4) Pax-6对眼表维持的更大影响是什么？这些计划实验的结果将提供有关眼表生物学的基本信息，并将确定药物开发和基因治疗的分子靶点，以纠正眼表疾病。它们将进一步有助于解决与人工角膜生物工程相关的问题。

DESCRIPTION (provided by applicant): Little is understood about the mechanisms coordinating the balance between epithelial cell proliferation and cell differentiation necessary to maintain ocular surface health. In the past grant period, this project focused on the role of Matrix Metalloproteinase (MMP) gelatinase B (gelB; MMP-9), expression of which is induced at the front of the corneal epithelium migrating to resurface a wound. The novel finding was made that gelB modulates the proliferative balance in the regenerating epithelium. GelB deficiency in knock out mice accelerated cell proliferation in the regenerating epithelium, associated with premature accumulation of the cytokine IL-1alpha. In contrast, it was learned that this does not work in reverse, that IL-1 does not stimulate gelB expression in the absence of any other input. This is different from its effect on expression of other MMPs, and needs to be further understood. GelB deficiency was also associated with a delay in activation of Smad2 transcription factor in the regenerating epithelium, suggesting the mechanism for enhancing the proliferative rate. Another novel finding was that the transcription factor Pax-6 controls the GelB promoter in both a positive and negative manner, and is induced along with gelB at the migrating front of the corneal epithelium. Preliminary data suggests that Pax-6 deficiency is similar to gelB deficiency in its effect on ocular resurfacing. This new proposal builds on the conceptual framework developed in the last grant period, extending the studies to answer some of the questions raised by the new findings. A new focus will be signaling through the Epidermal Growth Factor Receptor (EGFR), and its modulation by G protein-coupled receptors (GPCRs), which are activated by corneal nerves. The: following questions will be addressed: 1) What controls gelB expression in the wound environment and can corneal nerves alter the capacity of IL-1 to control gelB expression? 2) How does gelB control IL-lalpha expression, and does IL-1alpha affect epithelial migration or proliferation? If so, can this explain the gelB-deficient phenotype? 3) How does gelB control Smad2 activity and how do nerves interact? 4) What are the larger effects of Pax-6 on maintenance of the ocular surface? Results of these planned experiments will provide basic information about the biology of the ocular surface, and will identify molecular targets for drug development and gene therapy to correct ocular surface disorders. They will be further useful in solving problems associated with bioengineering of artificial corneas.