Increased chondrocyte PPi production, and PPi-generating NTPPH activity are linked with CPPD crystal deposition disease, common in aging and osteoarthritic cartilage. Because the major chondrocyte NTPPPH is PC-1, we will study the regulation of PC-1 expression and the primary role PC-1 could play in crystal deposition and cartilage degeneration. We will: 1. Define the mechanism of PPi elaboration by chondrocytes: To define if PPi elaboration is critically regulated by TGFbeta-regulated expression and movement to the membrane of PC- 1, we will determine the distribution of cellular, membrane and secreted Pc-1 and NTPPH when PPi release is induced (using TGFbeta-stimulated chondrocytes, and SV40-immortalize chondrocytes transfected with PC-1. Soluble, secreted PC-1 cDNA and enzyme- deficient PC-1 cDNA will serve as controls, and we will concurrently measure the NTPPH substrate ATP, PPi, and pyrophosphatase activity. To directly test the roles of PC-1 transcription and translocation in chondrocyte PPI release, we will use antisense PC-1 and brefeldin A, respectively. Last, we will define the mechanisms for the known abilities or IL-1beta and IGF-1 to inhibit TGFbeta- induced chondrocyte PPi elaboration. 2. Define the relationship between PC-1 expression and chondrocyte differentiation and growth factor responsiveness: We will determine how PC-1 expression is regulated in distinct stages of chondrocyte differentiation and function (TGFbeta-regulated cell cycle progression, proliferative senescence, hypertrophy, apoptosis, de-differentiation). Because PC-1 is a major inhibitor of the insulin receptor kinase in fibroblasts, we will test the hypothesis that PC-1 expression directly influences chondrocyte responsiveness to growth factors, including the highly homologous IGF-1 receptor, by transfecting immortalized chondrocytes with PC-1. 3. Define the effects of increased PC-1 expression on cartilage in transgenic mice: To test the hypothesis that increased PC-1 exerts primary effects on cartilage in vivo, we will study mice from lineages transgenic for PC-1/NTPPPH, under control of the type II collagen promoter-enhancer. Control lineages transgenic for enzyme-deficient PC-1 will be studied. Cartilage morphology, crystal deposition, PPi concentration, and PC-1 and NTPPPH expression will be studied in transgenics (and nontransgenic littermates) allowed to age (to 18 months), using histomorphometry, histochemistry, radiography, atomic force microscopy and X-Ray diffraction.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Program Projects (P01)
Project #
2P01AG007996-07A1
Application #
6234152
Study Section
Project Start
1997-07-01
Project End
1998-03-31
Budget Start
1996-10-01
Budget End
1997-09-30
Support Year
7
Fiscal Year
1997
Total Cost
Indirect Cost
Name
Scripps Research Institute
Department
Type
DUNS #
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Chen, Liang-Yu; Lotz, Martin; Terkeltaub, Robert et al. (2018) Modulation of matrix metabolism by ATP-citrate lyase in articular chondrocytes. J Biol Chem 293:12259-12270
Matsuzaki, Tokio; Alvarez-Garcia, Oscar; Mokuda, Sho et al. (2018) FoxO transcription factors modulate autophagy and proteoglycan 4 in cartilage homeostasis and osteoarthritis. Sci Transl Med 10:
Su, Alvin W; Chen, Yunchan; Dong, Yao et al. (2018) Biomechanics of osteochondral impact with cushioning and graft Insertion: Cartilage damage is correlated with delivered energy. J Biomech 73:127-136
Abhishek, Abhishek; Neogi, Tuhina; Choi, Hyon et al. (2018) Review: Unmet Needs and the Path Forward in Joint Disease Associated With Calcium Pyrophosphate Crystal Deposition. Arthritis Rheumatol 70:1182-1191
Fisch, K M; Gamini, R; Alvarez-Garcia, O et al. (2018) Identification of transcription factors responsible for dysregulated networks in human osteoarthritis cartilage by global gene expression analysis. Osteoarthritis Cartilage 26:1531-1538
Ramdani, Ghania; Schall, Nadine; Kalyanaraman, Hema et al. (2018) cGMP-dependent protein kinase-2 regulates bone mass and prevents diabetic bone loss. J Endocrinol 238:203-219
Serrano, Ramon L; Chen, Liang-Yu; Lotz, Martin K et al. (2018) Impaired Proteasomal Function in Human Osteoarthritic Chondrocytes Can Contribute to Decreased Levels of SOX9 and Aggrecan. Arthritis Rheumatol 70:1030-1041
Jin, Yunyun; Cong, Qian; Gvozdenovic-Jeremic, Jelena et al. (2018) Enpp1 inhibits ectopic joint calcification and maintains articular chondrocytes by repressing hedgehog signaling. Development 145:
Grogan, Shawn P; Duffy, Stuart F; Pauli, Chantal et al. (2018) Gene expression profiles of the meniscus avascular phenotype: A guide for meniscus tissue engineering. J Orthop Res 36:1947-1958
Baek, Jihye; Sovani, Sujata; Choi, Wonchul et al. (2018) Meniscal Tissue Engineering Using Aligned Collagen Fibrous Scaffolds: Comparison of Different Human Cell Sources. Tissue Eng Part A 24:81-93

Showing the most recent 10 out of 321 publications