UV-INDUCED COLLAGENASE--A MOLECULAR BASIS FOR PHOTOAGING

这项提案中概述的研究将继续这一令人信服的发现。 长波紫外线照射促进培养的人胶原酶的产生 并进一步阐明皮肤成纤维细胞的生化和分子机制 紫外线对人体皮肤结缔组织损伤的机制 辐射(UVR)。光损伤在大多数皮肤白皙的人身上都可以看到 生命的第五个十年，临床上表现为皱纹、松弛和 脆弱的皮肤和组织学上由于弹性材料和 胶原蛋白的降解。导致这些的生化机制 人们对结缔组织的变化知之甚少。连接词的退化 组织在一定程度上是由一种叫做基质金属蛋白酶的酶来调节的。 (MMPs)，包括间质胶原酶和IV型胶原酶。 初步研究表明，剂量依赖性地增加了 培养人皮肤间质胶原酶及胶原酶mRNA的表达 经紫外线A照射的成纤维细胞这些初步数据支持 UVR诱导MMPs表达，导致结缔组织的假说 组织损伤。 本研究旨在探讨紫外线照射对基质金属蛋白酶体外合成的影响。 在活体内。长波和短波紫外线以及太阳能的影响-- 模拟辐射对基质金属蛋白酶的产生和表达的影响 人类常用的金属蛋白酶组织抑制物(TIMP) 培养中的成纤维细胞和角质形成细胞将被研究。一个 间质胶原酶、72-KD和92-KD的综合检测 IV型胶原酶和TIMP的体外调节将使用 功能、免疫学和分子生物学方法。特定的 实验将解决这些问题：a)细胞反应 取决于细胞年龄还是取决于过去的紫外线照射？B)进行细胞外 基质分子改变MMPs和TIMP对UVR的细胞反应？c) 胶原酶生成的抑制剂会改变细胞对UVR的反应吗？ D)UVR是否通过细胞因子间接调节MMPs和TIMP的表达？这个 紫外线照射对体内基质金属蛋白酶和金属基质金属蛋白酶合成及基因表达的影响 UVR照射人皮肤的免疫组织化学和组织化学研究 原位杂交技术，以及在人体皮肤上的移植 无性系小鼠。局部应用胶原酶抑制剂的疗效观察 防晒霜对紫外线诱导的基质金属蛋白酶和TIMP表达的影响将在 人体受试者和口服抑制剂的效果将是 采用无菌小鼠模型进行研究。

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.