5-5′-AGCTTGGGGACTTTCCGA-3′ DNA probe (Bio-Protech, Taipei, Taiwan) as fluorescence. Nuclear protein extracts from RAW 264.7 cells were prepared following the method of Chen et al. [23]. The DNA binding reaction with nuclear protein was performed at

room temperature in a volume of 20 μl, which contained the binding LY2606368 molecular weight buffer (10 mM Tris–HCl, pH 7.5, 50 mM NaCl, 1 mM dithiothreitol (DTT)), 1 μg of poly(dI-dC), 50 nM cy5.5-labeled probe, 0.5 % Tween 20, and 15 μg of nuclear extracts. After incubation for 30 min, the samples were electrophoresized on native 5 % acrylamide gels prepared in a 0.5× TBE buffer (AMRESCO, Solon, OH, USA). Supershift assays using anti-p65 and anti-p50 antibody were also conducted to confirm the specificity of NF-κB DNA-binding activity. “Cold” represents a nuclear extract preincubated with an excess of unlabeled oligonucleotide. The gel was subsequently imaged with a LI-COR Odyssey Infrared Imaging System (LI COR Biosciences, Lincoln, VX-770 research buy NE, USA) in 700-nm channels with a 169 μm resolution. The density

of fluorescence in each band was measured in triplicate using LI-COR imaging software. Immunofluorescent staining Effects of kinsenoside on the nuclear translocation of p65 were examined by immunofluorescence, as described previously [24]. Briefly, 5 × 104 RAW 264.7 cells were seeded onto a 24-well plate preseeded with coverslips. After overnight incubation to allow for cell attachment, the cells were preincubated with kinsenoside (10, 25, and 50 μM) for 2 h before stimulation for 1 h with RANKL (50 ng/ml). After incubation, cells were washed twice Thymidine kinase with 1× PBS, fixed for 15 min at room temperature with 4 % paraformaldehyde in 1× PBS (pH 7.4), and then washed extensively with 1× PBS. Cells were then permeabilized in 1× PBS containing 0.1 % Triton X-100. After blocking with 0.1 % BSA-PBS, cells were incubated at 4 °C overnight with anti-p65 antibody (Cell Signaling, Danvers,

MA, USA) diluted 1:200 in PBS. Cells were then labeled for 1 h at room temperature with an Alexa Fluor 488 phallotoxin (Molecular Probes, Inc., Eugene, OR, USA) diluted 1:500 in PBS. Cells were then washed in PBS as before, counterstained for 3 min at room temperature with 4′-6-diamidino-2-phenylindole (DAPI) (Santa Cruz Biotechnology, Inc., CA, USA), and mounted for confocal microscopy (Leica TCS SP2, Buffalo Grove, IL, USA). Luciferase assay To examine NF-κB activation, RAW 264.7 cells (5 × 104 in 1 ml of fresh medium) were seeded in a 24-well plate before transfection. The NF-κB luciferase reporter plasmids and pRL-TK used in this study were obtained from Promega (Madison, WI, USA). The DNA/jetPEI®-Macrophage mixture was then added to the cells. The cells were incubated in a humid atmosphere of 5 % CO2 at 37 °C for 6 h. After 6 h, the transfected cells were treated with kinsenoside for 120 min and then stimulated with RANKL (50 ng/ml) for 24 h.