Expression of cartilage intermediate layer protein/nucleotide pyrophosphohydrolase parallels the production of extracellular inorganic pyrophosphate in response to growth factors and with aging. Arthritis Rheum 2000 Dec;43(12):2703-11
Date
01/06/2001Pubmed ID
11145028DOI
10.1002/1529-0131(200012)43:12<2703::AID-ANR10>3.0.CO;2-YScopus ID
2-s2.0-0034545162 (requires institutional sign-in at Scopus site) 28 CitationsAbstract
OBJECTIVE: To evaluate the role of the extracellular inorganic pyrophosphate (ePPi)-generating ectoenzyme cartilage intermediate layer protein/nucleotide pyrophosphohydrolase (CILP/NTPPH) in chondrocyte PPi elaboration, we studied CILP/NTPPH expression in response to growth factors during aging.
METHODS: Porcine chondrocytes from adult (3-4-year-old) and young (2-week-old) animals were stimulated with transforming growth factor beta1 (TGFbeta1), which enhances ePPi elaboration, and/or insulin-like growth factor 1 (IGF-1), which diminishes ePPi elaboration. Measurements of ePPi, NTPPH enzyme activity, Western blot analysis, reverse transcriptase-polymerase chain reaction (RT-PCR), and Northern blot analysis were performed.
RESULTS: Elaboration of ePPi into conditioned media from adult chondrocytes was significantly increased by TGFbeta1 and significantly inhibited by IGF-1, but no significant differences were observed in young chondrocytes. The protein levels of CILP/NTPPH by Western analysis in the media from adult and young porcine chondrocytes were increased by TGFbeta1. RT-PCR and Northern analysis showed that CILP/NTPPH messenger RNA (mRNA) expression in both adult and young chondrocytes was increased by TGFbeta1 and decreased by IGF-1, but these changes were less significant in the young chondrocytes. Basal and TGFbeta1-up-regulated levels of CILP/NTPPH expression were higher in adult chondrocytes than in young chondrocytes.
CONCLUSION: These results provide evidence that CILP/NTPPH expression and ePPi elaboration are concomitantly stimulated by TGFbeta1 and down-regulated by IGF-1, especially in adult chondrocytes, implicating CILP/NTPPH as a functional participant in ePPi elaboration. Increased CILP/NTPPH mRNA expression in chondrocytes derived from aged animals compared with young animals might promote the formation of calcium pyrophosphate dihydrate crystals in aged cartilage.
Author List
Hirose J, Masuda I, Ryan LMMESH terms used to index this publication - Major topics in bold
AgingAnimals
Cartilage
Cells, Cultured
Culture Media, Conditioned
Diphosphates
Extracellular Space
Growth Substances
Phosphates
Pyrophosphatases
RNA, Messenger
Swine