Investigation of a factor in synovial fluid which suppresses inflammatory signalling in cartilage. (360G-Wellcome-078918_Z_05_Z)

The mechanism of activation of cJun-N-terminal Kinase (JNK) in articular cartilage in response to mechanical injury is unknown. Removal, or dilution ofsynovial fluid has been shown to activate JNK in cartilage. Initial characterisation of the suppressive activity in synovial fluid suggests that it may be due to a protein, between 5 and 50 kDa in size, which is not presentin plasma. This project aims to characterise this factor further, purify it from synovial fluid (using techniques such as ion exchange chromatography and electrophoresis) and identify it by mass spectrometry. A bioassay of ATF-2 suppressive activity will be used to indicate the presence, or absence, of thesuppressive factor. The role of the factor in cartilage and other tissues, particularly in the response to sharp injury will be explored. Antibodies to the factor will be generated and used for western blotting and immunohistochemistry. The factor's role in the regulation of other signalling pathways in articular cartilage will also be investigated, by phospho-western blotting of cartilage lysates. The nature of a suppressor of JNK in synovial