Collagenase degradation in extracellular matrix in aging

衰老过程中细胞外基质中胶原酶的降解

• 批准号: 7455845
• 负责人: GARY J FISHER
• 金额: $ 26.69万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7455845
• 关键词: Address; Adhesions; Age; Aging; Aging-Related Process; Antioxidants; Applications Grants; Biology; Blast Cell; Classification; Collagen; Collagen Fibril; Collagen Type I; Complex; Connective Tissue; Coupled; Data; Dependence; Dermal; Dermis; Enzymes; Equilibrium; Extracellular Matrix; Feedback; Fibrillar Collagen; Fibroblasts; Health; Heart; Human; Individual; Integrin alpha2beta1; Integrins; Interstitial Collagenase; JUN gene; Joints; Lung; MAPK8 gene; Measurement; Measures; Mechanics; Mediating; Mediator of activation protein; Modeling; Molecular; Molecular Analysis; Morbidity - disease rate; Motion; Organ; Pathway interactions; Population; Protein Overexpression; Proteins; Public Health; Reactive Oxygen Species; Regulation; Regulatory Pathway; Role; Sampling; Skin; Skin Aging; Structural Protein; Testing; Therapeutic; Transcript; Transcription Factor AP-1; Transforming Growth Factors; Work; age group; age related; aged; base; body system; bone; collagenase; design; enzyme activity; functional disability; human TGFB1 protein; improved; in vivo

DESCRIPTION (provided by applicant): Human skin, like all other organs, undergoes alterations as a consequence of aging. Reduced function of aged skin is largely caused by irreversible destruction of fibrillar collagen, the major structural protein in skin connective tissue (dermis). As the US population ages, morbidity from loss of collagen decline of skin connective tissue function is becoming an increasing public health concern. The long-term objective of this grant application is to understand molecular mechanisms that are responsible for degradation of fibrillar collagen during aging, and thereby develop preventative and therapeutic remedies to improve the health of aged human skin. We have found that matrix metalloproteinase-1 (MMP-1), the enzyme responsible for initiating cleavage of fibrillar collagen is significantly elevated in aged (>80 years old), compared to young (18-29 years old) human skin dermal fibroblasts in vivo. Overproduction of MMP-1 by dermal fibroblasts causes fragmentation and disorganization of collagen fibrils. This loss of structural integrity of collagen fibrils is a critical factor in the age-related functional impairment of human skin connective tissue. The specific focus of this grant application is to investigate molecular mechanisms that cause this age-dependent MMP-1 overexpression in human skin connective tissue. Based on our preliminary data obtained by direct measurements of young and aged human skin, we hypothesize that elevated MMP-1 levels in aged connective tissue results from the interdependent actions of four MMP-1 regulators: 1) transcription factor AP-1, 2) alpha2beta1 integrin, 3) transforming growth factor-beta1, and 4) reactive oxygen species. These four factors are coordinately regulated through mechanical tension exerted on dermal fibroblasts by its physical interactions with the collagenous extracellular matrix of skin connective tissue, in which they reside. MMP-1-mediated collagen fibril fragmentation results in weakened mechanical tension within dermal fibroblasts. This weakened mechanical tension promotes further expression of MMP-1, and thereby sets in motion a positive feedback pathway of skin connective tissue destruction. Our specific aims are designed to test this working model, using two experimental approaches; 1) direct measurements of relevant transcripts, proteins, and enzyme activities in small samples of human skin from individuals of different age groups, and 2) molecular analysis of MMP-1 regulation in a three dimensional collagen lattice fibroblast culture model, which recapitulates the salient features of MMP-1 overexpression observed in aged human skin connective tissue in vivo. By using these two experimental approaches in a systematic integrated manner, we will investigate the aging process directly in human's largest organ, skin. Given that connective tissue biology is similar throughout the body, our results will likely be directly applicable to many organ systems, including lung, bone, joints, and heart. In addition to testing our hypothesis regarding the mechanism of age-dependent regulation of MMP-1, our proposed studies will provide direct quantitative measures that address the question of "when does aging begin?", as it pertains to human skin connective tissue.

描述（由申请人提供）：与所有其他器官一样，人类皮肤会因衰老而经历改变。衰老皮肤的功能降低主要是由于原纤维胶原蛋白（皮肤结缔组织（真皮）中主要结构蛋白的不可逆转破坏引起的。随着美国人口年龄的增长，皮肤结缔组织功能胶原蛋白衰落的发病率正在成为越来越多的公共卫生问题。该赠款应用的长期目标是了解衰老期间原纤维胶原蛋白降解的分子机制，从而开发预防和治疗疗法以改善老年人皮肤的健康。我们发现，与年龄（18-29岁的）人类皮肤皮肤皮肤成纤维细胞相比，在老年（> 80岁）中，负责启动纤维胶原裂解的酶的基质金属蛋白酶1（MMP-1）显着升高。通过真皮成纤维细胞生产MMP-1会导致胶原纤维的破碎和混乱。胶原原纤维的结构完整性丧失是人类皮肤结缔组织与年龄相关的功能障碍的关键因素。该赠款应用的特定重点是研究引起这种依赖年龄的MMP-1过表达的分子机制。 Based on our preliminary data obtained by direct measurements of young and aged human skin, we hypothesize that elevated MMP-1 levels in aged connective tissue results from the interdependent actions of four MMP-1 regulators: 1) transcription factor AP-1, 2) alpha2beta1 integrin, 3) transforming growth factor-beta1, and 4) reactive oxygen species.这四个因素通过与皮肤结缔组织的胶原胶外基质基质（其驻留在皮肤上）的物理相互作用，通过在皮肤成纤维细胞上施加的机械张力进行协调调节。 MMP-1介导的胶原原纤维碎裂导致皮肤成纤维细胞内的机械张力减弱。这种减弱的机械张力促进了MMP-1的进一步表达，从而使皮肤结缔组织破坏的正反馈途径启动。我们的具体目标旨在使用两种实验方法测试该工作模型。 1）直接测量来自不同年龄段的个体人类皮肤的小样本中相关转录物，蛋白质和酶活性，以及​​2）在三维胶原蛋白胶原蛋白成纤维细胞培养模型中对MMP-1调节的分子分析，该模型将MMP-1过表达的人在凝乳组织中的敏感性与敏感性相结合。通过以系统的综合方式使用这两种实验方法，我们将直接研究人类最大的器官皮肤的老化过程。鉴于结缔组织生物学在整个身体中相似，因此我们的结果可能直接适用于许多器官系统，包括肺，骨，关节和心脏。除了测试有关MMP-1年龄依赖性调节机制的假设外，我们提出的研究还将提供直接的定量措施，以解决“何时开始衰老？”的问题，因为它与人类皮肤结缔组织有关。