Fig. 7.

Effect of knocking down HNF-4α on store-operated Ca²⁺ entry (SOCE) in human MCs. Fura-2 fluorescence ratiometry was used to assess the intracellular Ca²⁺ concentration ([Ca²⁺]_i). SOCE was evaluated using a Ca²⁺-readmission protocol. A–C: representative traces showing cyclopiazonic acid (CPA; 25 μM)-evoked Ca²⁺ responses in human MCs without transfection (Untran), transfected with scrambled siRNA (Scr), or transfected with siRNA against human HNF4α (siHNF4α). Traces were smoothed using SigmaPlot program (version 11.0). [Ca²⁺]_B is the Ca²⁺ concentration in the bathing solution. SOCE was the increase in [Ca²⁺]_i upon switch of the bathing solution from Ca²⁺-free to 2 mM Ca²⁺ solution. The numbers inside the horizontal bar on the top of each graph indicate the Ca²⁺ concentration in the bathing solution. D: summary data showing SOCE in Untran, Scr, and siHNF4α groups of human MCs. *P < 0.05 compared with both Untran and Scr groups. n is the number of cells analyzed in each group.