Adenoviral <scp>CCN</scp>3/<scp>NOV</scp> gene transfer fails to mitigate liver fibrosis in an experimental bile duct ligation model because of hepatocyte apoptosis

Abstract Background and Aims CCN 3/ NOV , a matricellular protein of the CYR61‐CTGF‐NOV ( CCN ) family, comprises six secreted proteins that associate specifically with the extracellular matrix. CCN proteins lack specific high‐affinity receptors; instead, they regulate crucial biological processes, such as fibrosis, by signalling via integrins and proteoglycans. Recent studies have linked overexpression of CCN 3/ NOV to mitigate kidney fibrosis. This study aims to investigate CCN 3/ NOV overexpression in liver fibrogenesis in vivo . Methods The biological efficacy of adenoviral expressed CCN 3/ NOV directed under transcriptional control of the constitutively active Cytomegalovirus promoter (Ad‐ NOV ) was analysed in a bile duct ligation model and in cultured primary hepatocytes. Results and Conclusions Even though Ad‐ NOV gene transfer in a 3‐week bile duct ligation mouse model showed the expected high levels of CCN 3/ NOV in both mRNA and protein, it failed to reduce liver fibrogenesis, but instead enhanced hepatocyte apoptosis. Furthermore, overexpressed CCN 3/ NOV in cultured primary hepatocytes resulted in decreased levels of CCN 2/ CTGF , the profibrotic marker protein in liver fibrosis. Both Ad‐ NOV and Ad‐ CTGF induced reactive oxygen species production, enhanced p38 and JNK activation. Therefore, we conclude that CCN 3/ NOV overexpression in vivo is insufficient to mitigate liver fibrogenesis because of the induction of hepatocyte injury and apoptosis.