Transduction mechanisms of porcine chondrocyte inorganic pyrophosphate elaboration

Objective. To investigate cellular signaling mechanisms that influence chon drocyte production of inorganic pyrophosphate (PPI), which promotes calcium pyrophosphate dihydrate (CPPD) crystal deposition. Methods. Articular chondrocyte and cartilage cultures were stimulated with protein kinase C (PKC) activator and adenyl cyclase activator. Generation o f extracellular PPi was measured. Results. Adenyl cyclase activation resulted in diminished pyrophosphate gen eration. PKC activation stimulated pyrophosphate elaboration. Conclusion. Two signaling pathways, cAMP and PKC, modulate generation of ex tracellular pyrophosphate by cartilage and chondrocytes. They are novel tar gets for potentially diminishing extracellular pyrophosphate elaboration th at leads to CPPD crystal deposition.