METALLOPROTEINASES IN NORMAL & KERATOCONUS CORNEAS

金属蛋白酶（MP）是一个酶家族，包括I型 胶原酶、溶基质素和IV型胶原酶。 底物特异性 用于MP的包括胶原蛋白、蛋白聚糖、层粘连蛋白、纤连蛋白、α-1 蛋白酶抑制剂，酪蛋白和明胶，其中许多是发现在 人类角膜 这些酶可能在正常的 结缔组织建模和某些病理过程，例如 圆锥角膜（KC）。 这项建议是基于这样一种信念，即议员们是 在人类角膜中具有重要功能的蛋白质。 仅I型 胶原酶在角膜中已被广泛研究。 令人惊讶的是，我们 初步数据表明，IV型胶原酶代表了 MP的主要活动。 基于这些新的研究，我们的假设是 不同的组织和细胞类型可能有不同的调节机制， MP酶的机制，这些调节控制之一是 在KC角膜中改变，从而导致IV型胶原酶增加 活动 在正常的人类角膜中，我们的具体目标是使用生物化学， 免疫组化和分子方法：（1）检查和比较所有 角膜和巩膜器官培养物中的MP活性;（2）确定是否 不同的蛋白水解活性是相同酶的修饰，或者 不同的酶;（3）检查MP的生物合成速率和调节， 不同的组织和细胞类型;和（4）在不同的组织中定位MP。 使用相同的方法，我们的KC研究的具体目标是：（1） 确认KC角膜基质细胞MP研究并研究KC器官培养;（2） 比较正常角膜和KC角膜的生物合成速率和MP的调节;（3） 确定KC角膜中观察到的MP活性增加是否是由于 氨基酸序列或异常翻译后修饰;（4） 定位KC和正常角膜中的MP;和（5）确定是否减少 MP的组织抑制剂水平可能是导致 在KC看到的活动。 到目前为止，还没有一个全面的 人角膜中MP活性的研究 在正常人角膜中的研究不仅仅是试图阐明KC的病因。 角膜或巩膜融化是角膜溃疡的重要特征， 碱烧伤，维生素A缺乏相关的角膜软化症，巩膜软化症 与结缔组织疾病相关的穿孔和巩膜融化。 我们在正常眼组织中的数据将为未来的研究提供基线数据。 研究这些病理性的蛋白水解活性， 条件

Metalloproteinases (MPs) are a family of enzymes which includes type I collagenase, stromelysin, and type IV collagenase. Substrate specificity for MPs include collagen, proteoglycans, laminin, fibronectin, alpha-1 proteinase inhibitor, casein, and gelatin, many of which are found in the human cornea. These enzymes may play an important role in normal connective tissue modeling and certain pathological processes, such as keratoconus (KC). This proposal is based on the belief that MPs are functionally important proteins within the human cornea. Only type I collagenase has been studied extensively in cornea. Surprisingly, our preliminary data indicate that type IV collagenase represents the predominant MP activity. Based upon these new studies, our hypothesis is that different tissues and cell types may have different regulatory mechanisms for MP enzymes and that one of these regulatory controls is altered in KC corneas thereby leading to increased type IV collagenase activity. In normal human cornea our specific aims are to use biochemical, immunohistochemical and molecular methods to: (1) examine and compare all MP activities in cornea and sclera organ cultures; (2) determine if different proteolytic activities are a modification of the same enzyme or different enzymes; (3) examine MP biosynthetic rates and regulation in different tissue and cell types; and (4) localize MPs in different tissues. Using the same methods, the specific aims for our KC studies are to: (1) confirm KC keratocyte MP studies and investigate KC organ cultures; (2) compare normal and KC cornea biosynthetic rates and regulation of MPs; (3) determine if increased MP activities seen in KC corneas are due to abnormal amino acid sequence or abnormal post translational modification; (4) localize MPs in KC and normal corneas; and (5) determine if decreased levels of tissue inhibitor of MPs could be responsible for increased activities seen in KC. To date there has been no comprehensive investigation of MP activities in human corneas Understanding of the MPs in normal human corneas goes beyond trying to elucidate the etiology of KC. Corneal or scleral melting is an important feature of corneal ulceration, alkali burns, vitamin A deficiency related keratomalacia, scleromalacia perforans and scleral melting associated with connective tissue diseases. Our data in normal ocular tissues will provide baseline data for future studies to investigate proteolytic activities in these pathological conditions.