TYPE IV COLLAGEN PEPTIDES-RECPTORS IN CORNEAL FUNCTION

角膜是一种有吸引力的伤口愈合模型，因为它具有 相对简单和独特的伤口愈合特性。 的 建议的研究将使用IV型胶原蛋白纯化片段， 化学合成的肽，目的是定义 角膜上皮细胞粘附的分子机制 和细胞迁移。 这些研究的最终目标是 开发肽药物以调节角膜伤口愈合。 从这些研究中获得的信息可能适用于 伤口愈合一般。 在这些研究中，我们将评估 角膜上皮细胞粘附和扩散到IV型 胶原蛋白，确定的IV型胶原蛋白水解片段，和 来自IV型胶原的合成肽。 接下来我们就 评价化学合成肽的能力， IV型胶原蛋白的不同区域以刺激迁移 角膜上皮细胞。 在这些研究中， （迁移到附着的基质）和趋化性（迁移到 溶液相配体）。 整合素是一种主要的 细胞外基质的一类细胞表面受体， 基底膜分子 整合素是复杂的异源二聚体 具有重要的生物学功能。 我们将定义整合素 人角膜上皮细胞上介导粘附的“受体” 以及向IV型胶原和特异性合成肽的迁移 来自IV型胶原的配体。 一组特定的抗- α链抗体和特异性抗β链抗体将 用于描绘完整的整联蛋白补体。 最后，我们将 测试高度纯化的IV型胶原结构域的影响，或 来自IV型的片段和化学合成的肽 胶原对兔角膜上皮细胞迁移的影响 体外器官培养测定系统。 我们发现了三个明显的 由IV型胶原蛋白氨基酸衍生的合成肽 促进角膜细胞粘附的HEP-1和HEP-2 NC 1区和来自三螺旋区的HEP-3。 HEP- 3肽，促进角膜上皮细胞粘附，出现 代表IV型胶原蛋白的序列， 刺激细胞迁移。 似乎其他人 序列存在于螺旋片段中尚未测试的区域中 其还可以具有细胞粘附或细胞迁移促进作用， 容量 这些发现有助于分子解剖 基底膜的结构和功能，它们可以作为 开发治疗剂以改变角膜的基础 上皮细胞的行为，以便有一个有益的影响， 临床条件。

The cornea is an attractive wound healing model because it has relatively simple and unique wound healing characteristics. The proposed studies will use type IV collagen purified fragments and chemically synthesized peptides with an objective of defining the molecular mechanisms involved in corneal epithelial cell adhesion and cell migration. The ultimate goal of these studies will be to develop peptide pharmaceuticals to modulate corneal wound healing. The information learned from these studies may have application to wound healing in general. In these studies we will evaluate the adhesion and spreading of corneal epithelial cells to type IV collagen, defined type IV collagen proteolytic fragments and synthetic peptides derived from type IV collagen. Next, we will evaluate the ability of chemically synthesized peptides from different regions of type IV collagen to stimulate the migration of corneal epithelial cells. In these studies both haptotaxis (migration to substratum attached) and chemotaxis (migration to solution phase ligands) will be determined. Integrins are a major class of cell surface receptors for extracellular matrix and basement membrane molecules. Integrins are complex heterodimers with important biological functions. We will define the integrin "receptors" on human corneal epithelial cells that mediate adhesion and migration to type IV collagen and specific synthetic peptide ligands derived from type IV collagen. a battery of specific anti- alpha chain antibodies and specific anti-beta chain antibodies will be used to delineate the full integrin complement. Lastly, we will test the influence of highly purified type IV collagen domains or fragments and chemically synthesized peptides derived from type IV collagen on the migration of rabbit corneal epithelial cells in the in vitro organ culture assay system. We have found three distinct synthetic peptides derived from the type IV collagen amino acid sequence that promote corneal cell adhesion: HEP-1 and HEP-2 from the NC1 region, and HEP-3 from the triple helical region. The HEP- 3 peptide, which promotes corneal epithelial cell adhesion, appears to represent a sequence of type IV collagen that is very important for stimulating cell migration. It seems likely that other sequences exist within the helical fragment in areas not yet tested that may also have cell adhesion or cell migration promoting capacity. These findings contribute to the molecular dissection of basement membrane structure and function, and they may serve as the basis for developing therapeutic agents to modify corneal epithelial behavior so as to have a salutary effect in problematic clinical conditions.