The Hippo pathway effector YAP controls mouse hepatic stellate cell activation

We identified the Hippo pathway and its effector YAP as a key pathway that controls stellate cell activation. YAP is a transcriptional co-activator and we found that it drives the earliest changes in gene expression during stellate cell activation. Activation of stellate cells in vivo by CCl4 or activation in vitro caused rapid activation of YAP as revealed by its nuclear translocation and the induction of YAP target genes. Hepatic stellate cells were isolated from BALB/c livers. Healthy mice were used for isoaltion of quiescent cells, CCl4 treated fibrotic mice were used for isolation of activated cells. In vitro activation was obtained by culturing fresh quiescent cells on plastic dishes for 10 days