Down-regulation of focal adhesion kinase by short hairpin RNA increased apoptosis of rat hepatic stellate cells

Abstract

Focal adhesion kinase (FAK) plays an essential role in the activation of hepatic stellate cells (HSC). The role of FAK on proliferation and apoptosis of fibronectin (FN)-stimulated HSC was investigated using short hairpin RNA (shRNA)-mediated gene silencing technology. FAK shRNA decreased the expressions of FAK, p-FAK (Tyr(397)), ERK(1), and p-ERK(1). FAK gene silencing also inhibited HSC proliferation by 11.08% at 12-h, 15.12% at 24-h, and 28.62% at 48-h post-transfection. Flow cytometric analysis (FACS) revealed that the apoptotic rate at 24 h was increased in the FAK shRNA plasmid group compared with the HK group (8.29 ± 0.79% vs 2.70 ± 0.31%, p < 0.01). TUNEL also confirmed the increase in the rate of apoptosis (19.00 ± 0.92% vs 7.63 ± 0.70%, p < 0.01), and studies showed that the caspase-3 expression was increased while the ratio of Bcl-2 to Bax was decreased. Together, these data show that FAK regulates HSC proliferation and induces the apoptosis of HSC via the caspase-3 and Bcl-2/Bax pathway.