TYPE IV COLLAGEN PEPTIDES-RECPTORS IN CORNEAL FUNCTION

角膜是一种有吸引力的伤口愈合模型，因为它有 相对简单而独特的伤口愈合特点。这个 拟议的研究将使用IV型胶原纯化片段和 化学合成的多肽，目的是定义 角膜上皮细胞黏附的分子机制 和细胞迁移。这些研究的最终目标将是 开发调节角膜伤口愈合的多肽药物。 从这些研究中获得的信息可能适用于 伤口一般都在愈合。在这些研究中，我们将评估 角膜上皮细胞对IV型角膜上皮细胞的黏附和扩散 胶原蛋白，定义的IV型胶原蛋白水解物片段和 从IV型胶原蛋白中提取的合成肽。接下来，我们将 评价化学合成多肽的能力 IV型胶原的不同区域刺激迁移 角膜上皮细胞。在这些研究中，两种触觉趋向性 (迁移到附着底物)和趋化性(迁移到 溶液相配体)将被确定。整合素是主要的 细胞外基质的细胞表面受体类和 基底膜分子。整合素是一种复杂的杂二聚体 具有重要的生物功能。我们将定义整合素 人角膜上皮细胞上介导黏附的“受体” 并向IV型胶原和特异性合成肽迁移 来源于IV型胶原的配体。一组特定的抗- 阿尔法链抗体和特异性抗β链抗体将 用来描绘完整的整合素补体。最后，我们将 检测高纯度的IV型胶原区对小鼠的影响 来源于IV型的片段和化学合成肽 胶原对兔角膜上皮细胞迁移的影响 体外器官培养检测系统。我们发现了三个不同的 IV型胶原氨基酸来源的合成肽 促进角膜细胞黏附的序列：HEP-1和HEP-2 Nc1区和来自三螺旋区域的Hep-3。HEP- 促进角膜上皮细胞黏附的3肽出现 来代表IV型胶原的序列，这是非常重要的 用来刺激细胞迁移。似乎很可能是其他人 序列存在于尚未检测的区域中的螺旋片段内 也可能有细胞黏附或细胞迁移促进作用 容量。这些发现为分子解剖做出了贡献 基底膜的结构和功能，它们可以作为 开发改良角膜的治疗剂的基础 上皮性行为，以便对有问题的人产生有益的影响 临床情况。

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.