Human skin, like all other organs, undergoes alterations as a consequence of the passage of time. In aged human skin, the dermal connective tissue architecture undergoes progressive degradation, which impairs skin function and causes skin to become thin and fragile. Aged skin bruises easily. Wound healing is slow and incomplete, further weakening the skin. Skin fragility largely results from irreversible deterioration of the structure and organization of fibrillar collagen, the most abundant structural protein in skin. The long-term goal of the parent proposal and this supplemental revision is to delineate mechanisms that are responsible for structural and functional deterioration of collagen fibrils that occur during human skin aging. Based on our preliminary data, we hypothesize that skin aging begins at a relatively young age brought about by gradual accumulation of partially degraded collagen, which results from matrix metalloproteinase-1 (MMP-1)-catalyzed collagen cleavage. This collagen breakdown alters interactions between the dermal extracellular matrix and fibroblasts, which produce, organize and directly contact the extracellular matrix. The impact of broken collagen is to reduce dynamic mechanical tension exerted between fibroblasts and the extracellular matrix. Reduced mechanical tension alters fibroblast function;inducing MMP-1 expression and lowering collagen production, thereby causing further deterioration of skin connective tissue. To directly test this hypothesis, we have generated transgenic mice that constitutively express high levels of MMP-1 in skin. In support of our hypothesis, skin connective tissue in these mice undergoes rapid deterioration, which resembles that observed in aged human skin. This supplemental revision application proposes to utilize this newly created mouse model of skin connective aging to investigate molecular mechanisms by which MMP-1-mediated collagen fragmentation alters fibroblast function during the aging process.

Public Health Relevance

The long-term goal of the parent proposal and this supplemental revision is to delineate mechanisms that are responsible for structural and functional deterioration of skin connective tissue, which occurs during human skin aging. This age-related degradation of skin causes skin to become thin and fragile. Aged skin bruises easily and heals poorly. As the United States population ages, the deleterious impact of aging on skin function is a rising, significant health concern.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
3R01AG025186-04S1
Application #
7816110
Study Section
Special Emphasis Panel (ZRG1-BDA-M (95))
Program Officer
Williams, John
Project Start
2009-09-30
Project End
2012-08-31
Budget Start
2009-09-30
Budget End
2012-08-31
Support Year
4
Fiscal Year
2009
Total Cost
$421,070
Indirect Cost
Name
University of Michigan Ann Arbor
Department
Dermatology
Type
Schools of Medicine
DUNS #
073133571
City
Ann Arbor
State
MI
Country
United States
Zip Code
48109
Fisher, Gary J; Shao, Yuan; He, Tianyuan et al. (2016) Reduction of fibroblast size/mechanical force down-regulates TGF-? type II receptor: implications for human skin aging. Aging Cell 15:67-76
Quan, Taihao; Fisher, Gary J (2015) Role of Age-Associated Alterations of the Dermal Extracellular Matrix Microenvironment in Human Skin Aging: A Mini-Review. Gerontology 61:427-34
Quan, Taihao; Johnston, Andrew; Gudjonsson, Johann E et al. (2015) CYR61/CCN1: A Novel Mediator of Epidermal Hyperplasia and Inflammation in Psoriasis? J Invest Dermatol 135:2562-2564
Xia, Wei; Quan, Taihao; Hammerberg, Craig et al. (2015) A mouse model of skin aging: fragmentation of dermal collagen fibrils and reduced fibroblast spreading due to expression of human matrix metalloproteinase-1. J Dermatol Sci 78:79-82
Wang, Frank; Smith, Noah R; Tran, Bao Anh Patrick et al. (2014) Dermal damage promoted by repeated low-level UV-A1 exposure despite tanning response in human skin. JAMA Dermatol 150:401-6
Qin, Zhaoping; Voorhees, John J; Fisher, Gary J et al. (2014) Age-associated reduction of cellular spreading/mechanical force up-regulates matrix metalloproteinase-1 expression and collagen fibril fragmentation via c-Jun/AP-1 in human dermal fibroblasts. Aging Cell 13:1028-37
Xia, Wei; Hammerberg, Craig; Li, Yong et al. (2013) Expression of catalytically active matrix metalloproteinase-1 in dermal fibroblasts induces collagen fragmentation and functional alterations that resemble aged human skin. Aging Cell 12:661-71
Qin, Zhaoping; Fisher, Gary J; Quan, Taihao (2013) Cysteine-rich protein 61 (CCN1) domain-specific stimulation of matrix metalloproteinase-1 expression through ?V?3 integrin in human skin fibroblasts. J Biol Chem 288:12386-94
Quan, Taihao; Little, Emily; Quan, Hehui et al. (2013) Elevated matrix metalloproteinases and collagen fragmentation in photodamaged human skin: impact of altered extracellular matrix microenvironment on dermal fibroblast function. J Invest Dermatol 133:1362-6
Fang, Ming; Goldstein, Elizabeth L; Turner, A Simon et al. (2012) Type I collagen D-spacing in fibril bundles of dermis, tendon, and bone: bridging between nano- and micro-level tissue hierarchy. ACS Nano 6:9503-14

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