Maintenance of Ocular Surface Integrity

描述（由申请人提供）：对维持眼表健康所必需的上皮细胞增殖和细胞分化之间的平衡的协调机制知之甚少。在过去的资助期内，该项目集中于基质金属蛋白酶（MMP）明胶酶B（gelB; MMP-9）的作用，其表达在迁移至伤口表面的角膜上皮的前部被诱导。新的发现是gelB调节再生上皮的增殖平衡。基因敲除小鼠中GelB缺陷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，据了解，这并不反过来起作用，在没有任何其他输入的情况下，IL-1不刺激gelB表达。这与其对其他MMPs表达的影响不同，需要进一步了解。GelB缺陷也与Smad 2转录因子在再生上皮中的激活延迟有关，这表明了增强增殖率的机制。另一个新的发现是转录因子Pax-6以阳性和阴性方式控制GelB启动子，并且在角膜上皮的迁移前部沿着GelB被诱导。初步数据表明，Pax-6缺陷与gelB缺陷对眼部表面置换的影响相似。这一新提案建立在上一个赠款期制定的概念框架基础上，扩大了研究范围，以回答新发现提出的一些问题。一个新的焦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。The：将解决以下问题：1）在伤口环境中什么控制gelB表达，角膜神经能改变IL-1控制gelB表达的能力吗？2)gelB如何控制IL-1 α表达，IL-1 α是否影响上皮细胞迁移或增殖？如果是这样，这能解释gelB缺陷型吗？3)gelB如何控制Smad 2活性以及神经如何相互作用？4)Pax-6对维持眼表的更大影响是什么？这些计划的实验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。它们将进一步用于解决与人工角膜的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.