The long-range objectives of this application are to utilize the unique aspects of osteoclast motility as targets in the rational design of pharmacologic agents for regulation of bone remodeling. The central hypothesis that is being tested is that the gelsolin-based signaling complex of the osteoclast podosome is unique and provides tissue specificity and sensitivity, making it an attractive pharmacologic target. In this proposal, the downstream targets of the gelsolin complex, in particular, the PI 3-kinase that produces a signaling phospholipid (PIP3) that is used for podosome organization in osteoclast activation, will be analyzed. The hypothesis is that critical cell survival signals are stimulated by PIP3 during osteoclast motility through activation of Akt. Furthermore, PTEN will be studied for its regulation of Akt and PIP3. In the second series of experiments, studies are proposed to analyze the function of a newly identified osteoclast-specific protein, leupaxin, which associates with the cytoskeleton and a member of the focal adhesion kinase family of proteins, PYK2. In the third Specific Aim, the applicant proposes to test the hypothesis that the Arp2/3 complex regulates the pointed end turnover of podosome actin filaments, working in conjunction with gelsolin to regulate podosome assembly and turnover. Studies in this proposal will be performed in avian and murine osteoclasts that are transduced by fusion proteins containing a human immunodeficiency virus peptide, TAT, which can transduce proteins across cell membranes.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR041677-10
Application #
6374947
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Program Officer
Sharrock, William J
Project Start
1992-07-10
Project End
2005-08-31
Budget Start
2001-09-01
Budget End
2002-08-31
Support Year
10
Fiscal Year
2001
Total Cost
$287,120
Indirect Cost
Name
Barnes-Jewish Hospital
Department
Type
DUNS #
City
Saint Louis
State
MO
Country
United States
Zip Code
63110
Hruska, Keith A; Mathew, Suresh (2011) The roles of the skeleton and phosphorus in the CKD mineral bone disorder. Adv Chronic Kidney Dis 18:98-104
Hruska, Keith A; Choi, Eric T; Memon, Imran et al. (2010) Cardiovascular risk in chronic kidney disease (CKD): the CKD-mineral bone disorder (CKD-MBD). Pediatr Nephrol 25:769-78
Hruska, Keith A (2009) Vascular smooth muscle cells in the pathogenesis of vascular calcification. Circ Res 104:710-1
Sugatani, Toshifumi; Hruska, Keith A (2009) Impaired micro-RNA pathways diminish osteoclast differentiation and function. J Biol Chem 284:4667-78
Hruska, Keith A; Mathew, Suresh; Lund, Richard J et al. (2009) The pathogenesis of vascular calcification in the chronic kidney disease mineral bone disorder: the links between bone and the vasculature. Semin Nephrol 29:156-65
Mathew, Suresh; Lund, Richard J; Chaudhary, Lala R et al. (2008) Vitamin D receptor activators can protect against vascular calcification. J Am Soc Nephrol 19:1509-19
Hruska, Keith A; Mathew, Suresh; Lund, Richard et al. (2008) Hyperphosphatemia of chronic kidney disease. Kidney Int 74:148-57
Mathew, Suresh; Tustison, Kimberly S; Sugatani, Toshifumi et al. (2008) The mechanism of phosphorus as a cardiovascular risk factor in CKD. J Am Soc Nephrol 19:1092-105
Hruska, Keith A; Saab, Georges; Mathew, Suresh et al. (2007) Renal osteodystrophy, phosphate homeostasis, and vascular calcification. Semin Dial 20:309-15
Sugatani, T; Hruska, K A (2007) MicroRNA-223 is a key factor in osteoclast differentiation. J Cell Biochem 101:996-9

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