Luciferase Reporter Assay

To examine the NFATc1 activation, BMMs were transfected with luciferase reporter construct containing NFATc1-binding promoter element. The BMMs (1 × 10⁴ cells/well) were then plated in 96-well plates and pretreated with isofraxidin for 30 min and then stimulated with 100 ng/ml of RANKL for 8 h. At the end of the culture period, cell lysates were prepared, and the luciferase activity was measured using a luciferase assay system (Promega, Madison, WI, USA) according to the manufacturer’s instructions.