Figure 4.
Suppression of endogenous Bim expression decreases Aβ-induced neuronal death. Primary neuron cultures were transfected for 1 or 3 d with bim-specific siRNA (sibim), scrambled siRNA (ncbim), mismatched siRNA (mmbim), or siPORT amine vehicle (siPORT), or were untreated (Ctrl). A, Representative agarose gels of RT-PCR products show endogenous bim mRNA expression decreased only by specific bim siRNA (top) with no change in levels of β-actin, an internal control (bottom). B, Protein levels of Bim were similarly affected by the siRNA treatments, as determined by Western blot (top), with no change in β-tubulin levels (bottom). C, Relative amounts of Bim were determined by densitometric scanning of Western blots from three independent experiments. Data are represented as a mean (+SEM) percentage of vehicle-treated control (Ctrl) values. *p < 0.01 relative to 1 d ncbim control group; #p < 0.01 relative to 3 d ncbim control group. D, Neuron cultures were exposed for 48 h to 25 μm Aβ25–35 24 h after transfection with siRNA. Data show mean (+SEM) cell viability from a representative experiment (n = 4). *p < 0.01 relative to respective ncbim condition.