Knockdown of CHOP protects hIAPP-INS1E cells from induced apoptosis.

hIAPP-INS1E cells were transfected with 20 µM of siRNA CHOP or siRNA scramble (siRNA scr) as a control. Twenty-four hours after transfection, cells were treated with A) 0.5 µM Thp for 8 hours or B) high glucose (25 mM) and BSA-coupled palmitic acid (400 µM; HG+PA) for 24 hours, and protein expression levels for CHOP, ATF3 and tubulin were determined. Representative Western blotting images are represented from 3 to 5 individual experiments. Immunostaining (left panel) and quantification (right panel) of insulin positive beta-cells (red), cleaved caspase 3 (green) and nuclei (blue) of hIAPP-INS1E cells (Con) and hIAPP-INS1E cells transfected with siRNA scr or siRNA CHOP previously treated with C) Thp or D) HG+PA. Note the absence of cells containing insulin and cleaved caspsase 3 staining in cells transfected with siRNA CHOP as compared to Thp or HG+PA treated controls. Scale bar is 50 µm. Quantification is normalized to number of insulin + cells and expressed as mean ± S.E.M from three independent experiments. **p<0.01 and ***p<0.001 vs. controls. No statistical differences were found between controls and Thp siCHOP or HG+PA siCHOP.