AB0114 PTEN Expression in Fibroblast-like Synoviocytes of Rheumatoid Arthritis

BackgroundFibroblast-like synoviocytes (FLS), with some tumor-like characters, play a key role in the pathogenesis of rheumatoid arthritis (RA) [1]. Phosphatase and tensin homolog (PTEN) is a tumor suppressor gene, and its mRNA expression has been reported to be absent in the lining layer of RA synovium, which is supposed to contribute to the invasive behavior of RA-FLSs [2,3]. It has been demonstrated in various kinds of tumor cells that the PTEN protein is a negative regulator of the PI3K/Akt signal pathway [4]. However, data of the PTEN protein level in RA-FLSs and its effect on the phosphorylation status of Akt (Thr308) is limited.ObjectivesTo investigate the expression of PTEN gene in cultured human RA-FLSs and its effect on Akt (Thr308) phosphorylation status.MethodsFLSs were isolated from synovial tissues obtained from patients with RA, osteoarthritis (OA) or joint trauma during joint replacement surgery or arthroscopy, and each group contains 3 patients. The mRNA expression of PTEN was detected by RT-qPCR. The protein levels of PTEN, pAkt (Thr308) and total Akt, were measured by western blotting. The phosphorylation status of Akt was determined by protein expression ratio of pAkt (Thr308)/total Akt.ResultsThe expression of PTEN mRNA was significantly lower in RA-FLSs compared with OA-FLSs and joint trauma-FLSs (P0.05). Similarly, the PTEN protein level in RA-FLS was much lower than OA-FLSs and joint trauma-FLSs (P0.05). Moreover, the phosphorylation level of Akt (Thr308) in RA-FLSs was significantly higher than those in the other two control groups (P