Progranulin A mediated MET signalling is essential for liver morphogenesis in zebrafish

Regulation of embryonic liver growth remains largely elusive. Progranulin has been discussed in pathological liver growth; however, the functional role of Pgrn in embryonic liver growth has never been addressed. Knockdown of GrnA, the orthologue of mammalian pgrn in zebrafish, displayed a deficient hepatic outgrowth during hepatogenesis. Expression profiles manifested that pgrn-deficiency impaired hepatogenesis associated with dysregulation of Met signaling. Pgrn regulates hepatic expression of Met was further verified in vitro and in vivo. These results indicate that Pgrn is a novel factor required for embryonic hepatic outgrowth and reveal a novel link between Pgrn and Met signaling. To explore the GrnA induced genomic responses during hepatic outgrowth, mRNA expression profiles were compared from grnA morphants and control embryos using zebrafish 14K oligonucleotide microarray at 72 hpf, when hepatocytes were rapid proliferating.