The lipoxygenase (LOX) family of enzymes has well established roles in inflammation (5-LOX and the leukotrienes), and yet-to-be fully defined roles in cell differentiation and proliferation. The recent finding of a human genetic defect in two LOX enzymes associated with an inherited form of ichthyosis presents an opportunity to connect the functioning of these enzymes with a role in epidermal differentiation. The genetics identifies both 12R-LOX and eLOX3 (epidermal lipoxygenase-3) as defective in the families studied, and by implication, as playing a critical and important role in all normal individuals. We recently found a plausible biochemical explanation for the genetics: the two lipoxygenases, 12R-LOX and eLOX3 act in tandem to convert arachidonic acid to a specific epoxyalcohol metabolite. Here we propose to investigate the role of this LOX pathway, pursuing the overall hypothesis that it has a vital function in keratinocyte differentiation, by characterizing substrates, intermediates, and products of the intertwined LOX activities, and the ability of these metabolites to activate or modulate the differentiation process in keratinocytes.
The Specific Aims are: To characterize the enzymology and pathways of metabolism involving 12R-LOX and eLOX3; To determine the functional relationships between 12R-LOX and eLOX3 by analyses of their expression, activities and localization in cells and tissues;To determine the biological activities of the 12R-LOX/eLOX3-derived products The failure of keratinocytes to correctly differentiate is a hallmark of severe skin diseases like psoriasis or ichthyosis. The results of this study will help characterize a model for LOX enzyme activity in controlling cell differentiation in a well-defined human context of disease, as well as uncovering the activities of a new class of agents, epoxyalcohols and their derivatives, with the potential for future therapeutic interventions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR051968-05
Application #
7643290
Study Section
Arthritis, Connective Tissue and Skin Study Section (ACTS)
Program Officer
Baker, Carl
Project Start
2005-07-01
Project End
2011-06-30
Budget Start
2009-07-01
Budget End
2011-06-30
Support Year
5
Fiscal Year
2009
Total Cost
$251,037
Indirect Cost
Name
Vanderbilt University Medical Center
Department
Pharmacology
Type
Schools of Medicine
DUNS #
004413456
City
Nashville
State
TN
Country
United States
Zip Code
37212
Yamanashi, Haruto; Boeglin, William E; Morisseau, Christophe et al. (2018) Catalytic activities of mammalian epoxide hydrolases with cis and trans fatty acid epoxides relevant to skin barrier function. J Lipid Res 59:684-695
Hirabayashi, Tetsuya; Anjo, Tatsuki; Kaneko, Arisa et al. (2017) PNPLA1 has a crucial role in skin barrier function by directing acylceramide biosynthesis. Nat Commun 8:14609
Chiba, Takahito; Thomas, Christopher P; Calcutt, M Wade et al. (2016) The Precise Structures and Stereochemistry of Trihydroxy-linoleates Esterified in Human and Porcine Epidermis and Their Significance in Skin Barrier Function: IMPLICATION OF AN EPOXIDE HYDROLASE IN THE TRANSFORMATIONS OF LINOLEATE. J Biol Chem 291:14540-54
Newcomer, Marcia E; Brash, Alan R (2015) The structural basis for specificity in lipoxygenase catalysis. Protein Sci 24:298-309
Muñoz-Garcia, Agustí; Thomas, Christopher P; Keeney, Diane S et al. (2014) The importance of the lipoxygenase-hepoxilin pathway in the mammalian epidermal barrier. Biochim Biophys Acta 1841:401-8
Thomas, Christopher P; Boeglin, William E; Garcia-Diaz, Yoel et al. (2013) Steric analysis of epoxyalcohol and trihydroxy derivatives of 9-hydroperoxy-linoleic acid from hematin and enzymatic synthesis. Chem Phys Lipids 167-168:21-32
Zheng, Yuxiang; Yin, Huiyong; Boeglin, William E et al. (2011) Lipoxygenases mediate the effect of essential fatty acid in skin barrier formation: a proposed role in releasing omega-hydroxyceramide for construction of the corneocyte lipid envelope. J Biol Chem 286:24046-56
Zheng, Yuxiang; Brash, Alan R (2010) Dioxygenase activity of epidermal lipoxygenase-3 unveiled: typical and atypical features of its catalytic activity with natural and synthetic polyunsaturated fatty acids. J Biol Chem 285:39866-75
Zheng, Yuxiang; Brash, Alan R (2010) On the role of molecular oxygen in lipoxygenase activation: comparison and contrast of epidermal lipoxygenase-3 with soybean lipoxygenase-1. J Biol Chem 285:39876-87
Zheng, Yuxiang; Brash, Alan R (2010) Formation of a cyclopropyl epoxide via a leukotriene A synthase-related pathway in an anaerobic reaction of soybean lipoxygenase-1 with 15S-hydroperoxyeicosatetraenoic acid: evidence that oxygen access is a determinant of secondary reactions with fatty ac J Biol Chem 285:13427-36

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