Amelioration of collagen-induced arthritis in rats by adenovirus-mediated PTEN gene transfer

The phosphatidylinositol 3-kinase (PI 3-kinase)/Akt pathway is known to be activated in rheumatoid arthritis (RA) synovial tissue, which impacts cell growth, proliferation, survival, and migration. Phosphatase and tensin homolog deleted from chromosome 10 (PTEN) functions as a negative regulator of PI 3-kinase signaling, thus blocking Akt activation. The aim of this study was to examine the effect of PTEN gene transfer in rats with collagen-induced arthritis (CIA).

Adenoviral vectors encoding human PTEN (AdPTEN) or beta-galactosidase (AdLacZ) were injected intraarticularly into rats with CIA, and their treatment responses were monitored by measures of clinical, radiographic, and histologic changes. The expression of phosphorylated Akt, total Akt, vascular endothelial growth factor (VEGF), proinflammatory cytokines, and chemokines, as well as the extent of microvessel density in the ankle joints were determined.

AdPTEN treatment reduced Akt phosphorylation and decreased VEGF production in human RA synovial fibroblasts. Compared with AdLacZ treatment of the rats with CIA, AdPTEN treatment significantly reduced ankle circumference, articular index scores, radiography scores, and histology scores, and also decreased microvessel density and levels of VEGF and interleukin-1beta. Furthermore, PTEN gene transfer led to down-regulation of Akt activation and increased apoptosis in the ankle joints.

This study is the first to demonstrate the in vivo effect of intraarticular gene delivery of PTEN on amelioration of arthritis symptoms in rats with CIA, which involved antiangiogenic, antiproliferative, and antiinflammatory effects of PTEN via inhibition of the PI 3-kinase/Akt signaling pathway. Our findings also implicate the PI 3-kinase/Akt pathway as a therapeutic target for the treatment of RA or other inflammatory diseases.