(Verbatim) Reepithelialization is a fundamental requirement for successful wound healing and restoration of epidermal barrier function. Cells at the leading edge of the wound margin undergo a phenotypic conversion characterized by a dramatic re- organization of the cytoskeleton and associated junctional complexes. These include retraction of intermediate filaments from the cell surface, dissolution of most desmosomes and hemidesmosomes and partial or complete dissolution of the basement membrane. Desmosomes have been reported to disappear during the migratory phase of reepithelialization and reassembly of these intercellular junctions marks the end of keratinocyte migration; however, the mechanisms underlying dynamic regulation of desmosome assembly and disassembly are unknown. A role for the epidermal growth factor receptor (EGFR) in wound healing has been proposed. In particular, there is evidence that the EGFR and ligands are transiently up-regulated during the reepithelialization phase of wound repair. We have established stable cell lines to test the hypothesis that elevation of the EGFR confers changes in EGF-dependent cellular responses. We have determined that increased EGFR levels foster increased rate of cell migration and elevation of matrix degrading proteinase production. Importantly, we have found that EGF-dependent dissolution of desmosomal junctions is greatly augmented in EGFR overexpressing cells when compared to the control cell lines. In this proposal we will test the central hypothesis that EGF-dependent cellular response is not only modulated by the concentration and availability of ligand, but also at the level of receptor abundance. We will focus on studies to 1) identify the mechanisms involved in EGF-dependent desmosomal dissolution that are differentially regulated as a function of EGFR abundance and to 2) investigate EGF-stimulated signal transduction cascades that are required for loss of desmosomal integrity. In particular, we will address the underlying biochemical basis for EGF-dependent regulation of sustained extracellular signal regulated kinase/mitogen activated protein kinase (ERK/MAPK) which we have identified as a requirement for EGF-dependent colony dispersion, metalloproteinase-9 induction and desmosomal dissolution. We will also identify the functional contributions of a growth-factor induced transcription factor (Slug) known to modulate desmosomal integrity in adult epithelium. The proposed studies should provide insights into factors that govern keratinocyte outgrowth from a wound edge and the regulatory mechanisms involved in modulation of desmosome

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
3R01AR042989-07S2
Application #
6806296
Study Section
General Medicine A Subcommittee 2 (GMA)
Program Officer
Moshell, Alan N
Project Start
1995-09-01
Project End
2005-02-28
Budget Start
2003-03-01
Budget End
2004-02-29
Support Year
7
Fiscal Year
2004
Total Cost
$17,058
Indirect Cost
Name
University of New Mexico
Department
Type
Schools of Pharmacy
DUNS #
868853094
City
Albuquerque
State
NM
Country
United States
Zip Code
87131
Kusewitt, Donna F; Choi, Changsun; Newkirk, Kimberly M et al. (2009) Slug/Snai2 is a downstream mediator of epidermal growth factor receptor-stimulated reepithelialization. J Invest Dermatol 129:491-5
Cooper, Karen L; Liu, Ke Jian; Hudson, Laurie G (2009) Enhanced ROS production and redox signaling with combined arsenite and UVA exposure: contribution of NADPH oxidase. Free Radic Biol Med 47:381-8
Hudson, Laurie G; Newkirk, Kimberly M; Chandler, Heather L et al. (2009) Cutaneous wound reepithelialization is compromised in mice lacking functional Slug (Snai2). J Dermatol Sci 56:19-26
Hudson, Laurie G; Choi, Changsun; Newkirk, Kimberly M et al. (2007) Ultraviolet radiation stimulates expression of Snail family transcription factors in keratinocytes. Mol Carcinog 46:257-68
Zeineldin, Reema; Rosenberg, Martina; Ortega, Dominic et al. (2006) Mesenchymal transformation in epithelial ovarian tumor cells expressing epidermal growth factor receptor variant III. Mol Carcinog 45:851-60
Zeineldin, Reema; Hudson, Laurie G (2006) Epithelial cell migration in response to epidermal growth factor. Methods Mol Biol 327:147-58
Choi, Changsun; Hudson, Laurie G; Savagner, Pierre et al. (2006) An in situ hybridization technique to detect low-abundance slug mRNA in adherent cultured cells. Methods Mol Biol 326:173-88
Savagner, Pierre; Kusewitt, Donna F; Carver, Ethan A et al. (2005) Developmental transcription factor slug is required for effective re-epithelialization by adult keratinocytes. J Cell Physiol 202:858-66
Ding, Wei; Hudson, Laurie G; Liu, Ke Jian (2005) Inorganic arsenic compounds cause oxidative damage to DNA and protein by inducing ROS and RNS generation in human keratinocytes. Mol Cell Biochem 279:105-12
Shi, Honglian; Hudson, Laurie G; Ding, Wei et al. (2004) Arsenite causes DNA damage in keratinocytes via generation of hydroxyl radicals. Chem Res Toxicol 17:871-8

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