The long-term objective of this proposal is to elucidate the molecular mechanisms involved in actin ring formation and bone resorption. Bone resorption is the first step in bone remodeling. Actin ring formation has been shown to be a prerequisite for efficient bone resorption in osteoclasts. Recent preliminary studies from our laboratory suggest that N-WASP-Arp2/3 complex may have a role in the osteoclast actin ring formation. Tyrosine kinases such as PYK2 and Src are involved in the phosphorylation of N-WASP and N-WASP associated phosphoproteins. Moreover, tyrosine phosphatase (PTP-PEST) has a unique role in the modulation of tyrosine phosphorylation of N-WASP and the associated signaling molecules. We therefore hypothesize: 1. N-WASP coordinately activated by Cdc42, PtdIns P2 (PIP2), and kinase(s) can stimulate Arp2/3 mediated actin polymerization and actin ring formation in osteoclasts. 2. Src/PTP-PEST regulation of tyrosine phosphorylation of N-WASP and the associated signaling proteins is required for actin remodeling in the actin ring and bone resorption. Thus, our Specific Aims are to: 1. Determine the signal transduction mechanisms involved in N-WASP activation and actin ring formation. 2. Determine the regulation of tyrosine phosphorylation, actin ring formation, and bone resorption by PTP-PEST. The goal of this revised renewal application is to identify the underlying molecular mechanisms in actin ring formation. To advance the understanding of the mechanisms of bone resorption at the cellular and molecular level, different approaches will be used. HIV-TAT or adenoviral-mediated delivery of N-WASP, PTP-PEST, and kinases (Src and PYK2) into osteoclasts will be performed to identify the signal transduction mechanisms involved in the formation of N-WASP-Arp2/3 complex and actin ring. The binding sites of PTP-PEST with N-WASP will be characterized by the delivery of TAT-fused oligopeptides derived from proline-rich regions of PTP-PEST and N-WASP. We will analyze the effects of the above-mentioned treatments on actin ring formation and bone resorption. Identification of peptides that impede osteoclast function will be useful in the development of pharmacological agents, targeting osteoclast actin ring formation and bone resorption in disorders such as osteoporosis, periodontal disease, and osteoarthritis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR046292-07
Application #
7088781
Study Section
Skeletal Biology Structure and Regeneration Study Section (SBSR)
Program Officer
Sharrock, William J
Project Start
1999-08-01
Project End
2008-06-30
Budget Start
2006-07-01
Budget End
2007-06-30
Support Year
7
Fiscal Year
2006
Total Cost
$296,908
Indirect Cost
Name
University of Maryland Baltimore
Department
Dentistry
Type
Schools of Dentistry
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Chellaiah, Meenakshi A; Ma, Tao (2013) Membrane localization of membrane type 1 matrix metalloproteinase by CD44 regulates the activation of pro-matrix metalloproteinase 9 in osteoclasts. Biomed Res Int 2013:302392
Gupta, Aditi; Cao, Wei; Sadashivaiah, Kavitha et al. (2013) Promising noninvasive cellular phenotype in prostate cancer cells knockdown of matrix metalloproteinase 9. ScientificWorldJournal 2013:493689
Gupta, Aditi; Cao, Wei; Chellaiah, Meenakshi A (2012) Integrin ?v?3 and CD44 pathways in metastatic prostate cancer cells support osteoclastogenesis via a Runx2/Smad 5/receptor activator of NF-?B ligand signaling axis. Mol Cancer 11:66
Robertson, Brian W; Chellaiah, Meenakshi A (2010) Osteopontin induces beta-catenin signaling through activation of Akt in prostate cancer cells. Exp Cell Res 316:1-11
Robertson, Brian W; Bonsal, Lauren; Chellaiah, Meenakshi A (2010) Regulation of Erk1/2 activation by osteopontin in PC3 human prostate cancer cells. Mol Cancer 9:260
Ma, Tao; Sadashivaiah, Kavitha; Madayiputhiya, Nandakumar et al. (2010) Regulation of sealing ring formation by L-plastin and cortactin in osteoclasts. J Biol Chem 285:29911-24
Chellaiah, Meenakshi A; Schaller, Michael D (2009) Activation of Src kinase by protein-tyrosine phosphatase-PEST in osteoclasts: comparative analysis of the effects of bisphosphonate and protein-tyrosine phosphatase inhibitor on Src activation in vitro. J Cell Physiol 220:382-93
Desai, B; Ma, T; Zhu, J et al. (2009) Characterization of the expression of variant and standard CD44 in prostate cancer cells: identification of the possible molecular mechanism of CD44/MMP9 complex formation on the cell surface. J Cell Biochem 108:272-84
Desai, Bhavik; Ma, Tao; Chellaiah, Meenakshi A (2008) Invadopodia and matrix degradation, a new property of prostate cancer cells during migration and invasion. J Biol Chem 283:13856-66
Samanna, V; Ma, T; Mak, T W et al. (2007) Actin polymerization modulates CD44 surface expression, MMP-9 activation, and osteoclast function. J Cell Physiol 213:710-20

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