Specific inhibition of basic calcium phosphate and calcium pyrophosphate crystal-induction of metalloproteinase synthesis by phosphocitrate

H. S. Cheung, J. D. Sallis, J. A. Struve

Research output: Contribution to journalArticle

40 Scopus citations


Calcium pyrophosphate dihydrate (CPPD) and basic calcium phosphate (BCP) crystal deposition diseases are a group of heterogeneous arthritides which are a significant source of morbidity in the elderly. Both crystals induced mitogenesis and metalloproteinase (MP) synthesis and secretion by fibroblasts and chondrocytes which may promote degradation of intra-articular tissue. We have previously shown that phosphocitrate (PC), an inhibitor of hydroxyapatite crystallization, specifically blocks BCP crystal-induced mitogenesis in 3T3 cells. This led us to examine the effect of PC on BCP and CPPD crystal induction of MP synthesis in human fibroblasts. PC (10-3 to 10-4 M) specifically inhibited the crystal-induced collagenase and stromelysin mRNA accumulation while having no effect on epidermal growth factor-induced or basal levels of mRNA for both enzymes. Western blots (collagenase) of conditioned media confirmed that PC blocked crystal-induced proteinase secretion as well. Moreover, PC (10-3 M) also blocked the crystal induction of c-fos and c-jun. Since FOS and JUN proteins form a transacting activator (AP-1) for expression of collagenase and stromelysin genes, PC may block the synthesis of both enzymes by inhibiting the transcription of c-fos and c-jun.

Original languageEnglish (US)
Pages (from-to)105-111
Number of pages7
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Issue number2
StatePublished - Mar 1 1996
Externally publishedYes



  • AP-1
  • Calcium crystal
  • Inhibition
  • Metalloproteinase
  • Phosphocitrate

ASJC Scopus subject areas

  • Molecular Biology
  • Molecular Medicine
  • Biophysics

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