Lysyl oxidase (LOX) is a copper-dependent amine oxidase that oxidizes primary amine of peptidyl lysine/hydroxylysine of collagen and elastin to initiate a series of condensation reactions to form covalent intra/intermolecular cross-linking. However, recent studies have revealed that LOX plays critical roles in regulating cellular functions as well through the mechanisms that are not well understood. During the course of our studies on collagen modifying enzymes in bone biology, we obtained data indicating that LOX interacts with a potent growth factor, transforming growth factor-?1 (TGF-?1), in vitro and in bone matrix. In addition, LOX appears to suppress the TGF-?1 signaling likely through its amine oxidase activity. In the E18.5 LOX-null bone, the TGF-?1 signaling was enhanced, collagen matrix was disorganized and craniofacial bone development was impaired. Thus, we hypothesized that LOX oxidizes mature TGF-?1 in bone and regulates its signaling that is critical for collagen production/organization and mineralization. To test this hypothesis, we propose the following specific aims: 1. To investigate if LOX-mediated TGF-?1 oxidation occurs in bone matrix (1a) and in vitro (1b), 2. To investigate the effect of LOX enzyme on TGF-?1 signaling and its outcome (alkaline phosphatase activity, collagen synthesis/organization, mineralization) in vitro (2a) and ex vivo (2b). The data obtained from this study may provide an insight into a novel mechanism by which TGF-?1 function is regulated by an amine oxidase, LOX, and its biological significance in bone.

Public Health Relevance

This study will explore a novel function of lysyl oxidase, a copper-dependent amine oxidase, in controlling the function of a potent growth factor, TGF-21, in bone. The data obtained may provide an insight into a novel mechanism by which bone development and remodeling are regulated.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21DE019569-02
Application #
7826802
Study Section
Skeletal Biology Structure and Regeneration Study Section (SBSR)
Program Officer
Wan, Jason
Project Start
2009-07-01
Project End
2012-06-30
Budget Start
2010-07-01
Budget End
2012-06-30
Support Year
2
Fiscal Year
2010
Total Cost
$185,000
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Dentistry
Type
Schools of Dentistry
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
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Boushell, L W; Nagaoka, H; Nagaoka, H et al. (2011) Increased matrix metalloproteinase-2 and bone sialoprotein response to human coronal caries. Caries Res 45:453-9