UV-INDUCED COLLAGENASE--A MOLECULAR BASIS FOR PHOTOAGING

本提案中概述的研究将追求令人信服的发现 UVA照射刺激培养的人体中胶原酶的产生， 皮肤成纤维细胞，并进一步阐明生物化学和分子 紫外线对人体皮肤结缔组织损伤的机制 辐射（UVR）。 在大多数皮肤白皙的人中， 第五个十年的生活，并表现为临床皱纹，松弛， 脆弱的皮肤和组织学上的弹性组织增生物质的积累， 胶原降解 造成这些的生化机制 结缔组织的变化知之甚少。 结缔组织退化 组织中的一部分是由称为基质金属蛋白酶的酶介导的， 基质金属蛋白酶（MMPs），其包括间质胶原酶和IV型胶原酶。 初步研究表明， 人皮肤组织间质胶原酶及其mRNA表达 用紫外线A照射成纤维细胞。 这些初步数据支持 UVR诱导MMPs表达，导致结缔组织增生的假设 组织损伤 本研究旨在探讨紫外线辐射对体外培养的人骨髓基质细胞合成基质金属蛋白酶的影响 和体内。 长波和短波紫外线的影响，以及太阳能- 模拟辐射对MMPs产生和表达的影响， 金属蛋白酶组织抑制剂（TIMP）是人类的一种常见抑制剂， 将研究培养物中的成纤维细胞和角质形成细胞。 一 间质胶原酶、72-kD和92-kD型的综合检查 IV胶原酶和TIMP调节将在体外进行， 功能、免疫学和分子生物学方法。 具体 实验将解决这些问题：a）细胞反应 取决于细胞年龄还是过去的紫外线照射？ B）细胞外 基质分子改变细胞对MMPs和TIMP？ c）、 胶原酶产生抑制剂会改变细胞对紫外线辐射的反应吗？ d）UVR是否通过细胞因子间接调节MMP和TIMP的表达？ 的 紫外线照射对MMP和TIMP合成和基因表达影响将在体内进行， 研究在人类皮肤照射紫外线辐射使用免疫组化和在 原位杂交技术，以及在人类皮肤移植到 无胸腺小鼠 局部应用胶原酶抑制剂的效果 和防晒霜对紫外线诱导的MMP和TIMP表达的影响将在 和口服给药抑制剂的效果将被 使用无胸腺小鼠模型进行研究。

The studies outlined in this proposal will pursue the compelling finding that UVA irradiation stimulates collagenase production in cultured human skin fibroblasts and further elucidate the biochemical and molecular mechanisms of connective tissue damage in human skin caused by ultraviolet radiation (UVR). Photodamage is seen in most fair-skinned individuals by the fifth decade of life and is manifest clinically by wrinkled, lax and fragile skin and histologically by accumulation of elastotic material and collagen degradation. The biochemical mechanisms responsible for these connective tissue changes are poorly understood. Degradation of connective tissue is mediated, in part, by enzymes termed matrix metalloproteinases (MMPs), which include interstitial collagenase and type IV collagenases. Preliminary studies have demonstrated a dose dependent increase in interstitial collagenase and collagenase mRNA in cultured human skin fibroblasts irradiated with ultraviolet A. These preliminary data support the hypothesis that UVR induces expression of MMPs, resulting in connective tissue damage. This study will examine the effect of UVR on the synthesis of MMPs in vitro and in vivo. The effect of long- and short-wave UVR, as well as solar- simulating radiation, on the production and expression of MMPs, and their common inhibitor, tissue inhibitor of metalloproteinase (TIMP), by human fibroblasts and keratinocytes in culture will be investigated. A comprehensive examination of interstitial collagenase, 72-kD and 92-kD type IV collagenase and TIMP regulation in vitro will be undertaken using functional, immunological and molecular biological methods. Specific experiments will address these questions: a) Is cellular response dependent on cellular age or on past UVR exposure? b) Do extracellular matrix molecules alter the cellular response to UVR of MMPs and TIMP? c) Will inhibitors of collagenase production modify cellular responses to UVR? d) Does UVR indirectly regulate MMP and TIMP expression via cytokines? The effect of UVR on MMP and TIMP synthesis and gene expression in vivo will be studied in human skin irradiated with UVR using immunohistochemical and in situ hybridization techniques, as well as in human skin grafted onto athymic mice. The effect of topically applied inhibitors of collagenase and sunscreens on UV-induced MMP and TIMP expression will be studied in human subjects and the effect of orally administered inhibitors will be studied using the athymic mouse model.