Regulation of Extracellular Matrix Homeostatsis in Skin Aging

皮肤衰老过程中细胞外基质稳态的调节

• 批准号: 8512628
• 负责人: GARY J FISHER
• 金额: $ 28.48万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8512628
• 关键词: Age of Onset; Aging; Antioxidants; Behavior Control; Biochemical; Blood Vessels; Caring; Cell Culture Techniques; Cell Respiration; Cells; Collagen; Collagen Type I; Connective Tissue; Controlled Environment; Contusions; Data; Dermal; Dermis; Elderly; Epidermis; Epithelium; Extracellular Matrix; Extracellular Matrix Proteins; Fibroblasts; Free Radicals; Goals; Hair follicle structure; Human; Immune; Impairment; MADH3 gene; Mechanics; Mediating; Medical; Molecular; Nerve; Neurons; Organ; Pathway interactions; Population; Production; Property; Proteins; Public Health; Reactive Oxygen Species; Regulation; Research; Sebaceous Glands; Signal Pathway; Signal Transduction; Skiing; Skin; Skin Aging; Smooth Muscle Myocytes; Structural Protein; Structure; Study models; Sweat Glands; Testing; Time; Type I Procollagen; Wound Healing; age related; aged; appendage; base; cell behavior; cell type; connective tissue growth factor; in vivo; insight; oxidation; theories

The long-term goal of the proposed research is to understand molecular basis and functional impact of skin connective tissue aging. Skin, like all human organs, undergoes deleterious alterations as a consequence of the passage of time. Natural aging of skin is manifested primarily by thinning, largely due to loss of type I collagen in the dermis. Type I collagen is the most abundant protein in skin and confers structure, strength and resiliency. Age-dependent loss of collagen causes increased fragility and thereby makes skin more susceptible to bruising and impedes wound healing. Aging of the US population makes medical care of fragile skin a growing public health concern. In addition to being the largest human organ, skin is readily accessible for study. These unique properties of skin provide the opportunity study molecular mechanisms of aging in humans. The free radical theory of aging posits that natural aging is driven by cellular damage that results from oxidation by reactive oxygen species (ROS) that are generated as a consequence of aerobic metabolism. We find that ROS levels are elevated in aged human skin fibroblasts in vivo. Fibroblasts are the major cell type that produces type I collagen. In addition, we find that the TGF-¿/SMAD/CTGF axis, which is the major regulatory network that drives type I collagen production in skin, is impaired in aged human skin. This impairment results from decreased expression of SMAD3, which is a downstream effector of TGF-¿ actions, and reduced expression of connective tissue growth factor (CTGF), which is a multi-functional protein that acts in concert with TGF-¿ to regulate type I collagen expression. Furthermore, we find that mild, short-term oxidative exposure of primary cultured human dermal fibroblasts causes permanent cellular alterations that closely mimic those observed in fibroblasts in aged skin in vivo; namely, increased ROS, reduced SMAD3, reduced CTGF, and reduced type I collagen expression. Based on these observations, we hypothesize that increased ROS, reduces expression of SMAD3 and CTGF, which results in reduction of type I collagen production, in fibroblasts in aged human skin. We propose four Specific Aims to test this hypothesis: 1) determine age-related alterations of ROS, SMAD3, CTGF, and type I collagen production, in human skin fibroblasts in vivo, 2) determine the ability of topical anti-oxidant to reduce ROS levels, mitigate impairment of the TGF-¿/SMAD/CTGF axis, and induce type I collagen production, in aged human skin in vivo, 3) determine molecular mechanisms by which oxidative exposure reduces SMAD3, CTGF and type I collagen expression in human ski fibroblasts, and 4) determine molecular mechanisms by which CTGF regulates type I collagen expression. The results from the proposed studies will provide important insights regarding 1) the age of onset of human skin aging, 2) molecular actions of topical antioxidant, 3) mechanisms by which oxidative exposure regulates the TGF-¿/SMAD/CTGF axis, and 4) molecular basis by which CTGF cooperates with TGF-¿ in the regulation of type I collagen expression.

拟议研究的长期目标是了解皮肤的分子基础和功能影响 结缔组织老化。像所有人类器官一样，皮肤经历了有害的改变。 时间的流逝。皮肤的自然衰老主要通过稀疏来表现，这主要是由于I型损失 真皮中的胶原蛋白。 I型胶原蛋白是皮肤和收缩结构中最丰富的蛋白质 和弹性。胶原蛋白的年龄依赖性损失会导致脆弱性增加，从而使皮肤更多 容易受到瘀伤的影响，并阻碍伤口愈合。美国人口的衰老使脆弱的医疗护理 皮肤越来越关注公共卫生。除了成为最大的人体器官外，皮肤还很容易获得 进行研究。皮肤的这些独特特性提供了机会研究的机会研究分子机制 人类。衰老的自由基理论认为，自然衰老是由细胞损伤驱动的 来自有氧代谢而产生的活性氧（ROS）的氧化。 我们发现，体内人类皮肤成纤维细胞的老年皮肤成纤维细胞升高。成纤维细胞是主要细胞 产生I型胶原蛋白的类型。此外，我们发现TGF-€ /SMAD /CTGF轴，这是主要的 驱动皮肤中I型胶原蛋白产生的监管网络在老年人皮肤中受损。这 损伤是由SMAD3表达降低而导致的，Smad3是TGF-oocta的下游效应因子， 结缔组织生长因子（CTGF）的表达降低，这是一种多功能蛋白 与TGF- - 一起调节I型胶原蛋白表达。此外，我们发现短期，短期 原代培养的人真皮成纤维细胞的氧化暴露会导致永久性细胞改变 密切模仿体内老化皮肤的成纤维细胞中观察到的。即，ROS增加，SMAD3减少， 减少CTGF和I型胶原蛋白表达减少。基于这些观察，我们假设 ROS增加，降低SMAD3和CTGF的表达，从而减少I型胶原蛋白 生产，在衰老的人类皮肤的成纤维细胞中。我们提出了四个特定的目的来检验这一假设：1） 确定ROS，SMAD3，CTGF和I型胶原蛋白产生的与年龄相关的变化，在人类皮肤中 体内成纤维细胞，2）确定局部抗氧化剂降低ROS水平的能力，减轻损害 TGF- /SMAD /CTGF轴，并在体内诱导I型胶原蛋白产生，3）确定 氧化物暴露降低SMAD3，CTGF和I型胶原蛋白表达的分子机制 人类滑雪成纤维细胞和4）确定CTGF调节I型胶原蛋白的分子机制 表达。拟议研究的结果将提供有关1）发作年龄的重要见解 人类皮肤老化，2）局部抗氧化剂的分子作用，3）氧化物暴露的机制 调节tgf-€ /smad /ctgf轴，以及4）CTGF与TGF-€合作的分子基础 I型胶原蛋白表达的调节。