Since prior data suggests a role for plakoglobin in mediating apoptosis [29, 30], we next transfected primary normal or IPF fibroblasts with siRNA-PG or ΦsiRNA constructs followed by induction of apoptosis using a Fas-activating antibody and cycloheximide for 6 hours (N = 16 for both normal and IPF cells transfected with either ΦsiRNA or siRNA-PG) [23, 27, 31]. Here, FAS is linked to idiopathic pulmonary fibrosis.