Figure 8.

A reduced iPLA₂ level inhibits hypoxic nuclear shrinkage. The indicated dose of siRNA for GFP or iPLA₂ was transfected into CHO-k1 cells three times as described in Materials and methods. GFP was used as the negative control. (A) Expression of iPLA₂ protein was assessed by Western blotting. The lysates from GFP siRNA- or iPLA₂ siRNA-treated CHO-k1 cells were subjected to 15% SDS-PAGE followed by Western blotting with an antibody for iPLA₂, lamin B1, or GAPDH (Lamin B1 and GAPDH were loading controls). (B) CHO-k1 cells were transfected with siRNA for GFP (2 μg/well) or siRNA for iPLA₂ (6 μg/well), and then were exposed to normoxia or hypoxia for 36 h. Subsequently, the cells were stained with Hoechst 33342 and visualized under a fluorescence microscope. Bars, 10 μm. Note that siRNA for iPLA₂ (2 μg/well) showed similar results (not depicted). The average nuclear area is shown under the photograph.