Stimulation Of Mechano Growth Factor Expression By TNF-α，IL-1β In Human Fibroblast-like Synoviocytes Through The PKA/CREB Signaling Pathway

Mechanocytes are those that respond to mechanical signals, included osteoblasts,fibroblasts and endothelial cells as well as smooth, cardiac and skeletal muscle cells.When suffer from mechanical stimuli mechanocytes express an IGF-1isoform IGF-1Ec,called Mechano growth factor (MGF) in human. MGF has multiple physiologicalfunctions. It can activate satellite cells, promote their proliferated, help them fused withmuscle fiber to repair it; It also protects the myocardium by preserving contractilefuction; and efficiently promotes motor neuron rescue from avulsion or crush injury.These multiple physiological functions of MGF have a broad prospect in the applicationof tissue repair area. Tissue injuries always accompany with inflammatory response.Inflammatory factor TNF-α, IL-1β induced the second message cAMP expression inhuman fibroblasts, Nevertheless, cAMP promoted MGF expression. Therefore, is thereany connection between the regulation of MGF expression and the the inflammatoryresponse worth our discussion. The main experiments and results are as follows:①Used explant culture method to isolate human Fibroblast-like synoviocytes(FLSs). Characterize primary culture cell by H&E staining and immunohistochemicalstaining of fibroblast marker Vimentin. Establish the synovial cell bank essential for thesubsequent experiments.②Using Real-time PCR to detect MGF expression in FLSs and RA-FLSs. Theresults showed that the mean level of MGF in RA-FLSs was higher than in FLSs, butthere was no significant between two groups.③Treated FLSs with TNF-α、IL-1β and IL-6respectively, then detected theexpression of MGF mRNA. We found that TNF-α and IL-1β significantly induced MGFexpression. IL-6had no effect on MGF synthesis.④Pretreated FLSs with KT5720, a specific inhibitor of PKA signaling pathway,then treated cells with TNF-α、IL-1β respectively, isolated the total RNA and protein.Then we detected the mRNA level of MGF and protein expression of CREB andp-CREB which is downstream transcription factor of PKA. The results showed thatTNF-α and IL-1β induced MGF expression in human FLSs through PKA/CREBsignaling pathway.In summary, we demonstrated that TNF-α and IL-1β stimulated MGF expression inhuman FLSs through PKA/CREB signaling pathway.