[Knockdown of calreticulin increases intracellular Ca 2+ concentration and promotes apoptosis of HSC-LX2 human hepatic stellate cells]

Objective To investigate the effect of silencing calreticulin (CALR) gene on the apoptosis and intracellular Ca2+ concentration in HSC-LX2 human hepatic stellate cells. Methods Small interfering RNA (siRNA) targeting CALR was designed and transfected into HSC-LX2 cells by lipofectamine transfection, and then the cells with CALR knockdown were screened out. Apoptosis was detected by flow cytometry combined with annexin V-FITC/PI labeling. The intracellular Ca2+ concentration which was loaded with Fluo3-AM (calcium ion fluorescent probe) was observed by laser confocal microscope. The mRNA and protein levels of CALR, Bcl2 and BAX were detected by reverse-transcription PCR and Western blotting. Results Knockdown of CALR led to the increase of intracellular Ca2+ concentration, the increased apoptosis of HSC-LX2 cells, the up-regulation of BAX expression, down-regulation of Bcl2 and the obvious raise of BAX/Bcl2 ratio. Conclusion Knockdown of CALR can increase intracellular Ca2+ concentration, up-regulate the ratio of BAX/Bcl2 and promote the apoptosis of HSC-LX2 cells.