MiR-145 mediates zebrafish hepatic outgrowth through progranulin A signaling

PLoS One. 2017 May 22;12(5):e0177887. doi: 10.1371/journal.pone.0177887. eCollection 2017.

Abstract

MicroRNAs (miRs) are mRNA-regulatory molecules that fine-tune gene expression and modulate both processes of development and tumorigenesis. Our previous studies identified progranulin A (GrnA) as a growth factor which induces zebrafish hepatic outgrowth through MET signaling. We also found that miR-145 is one of potential fine-tuning regulators of GrnA involved in embryonic hepatic outgrowth. The low level of miR-145 seen in hepatocarinogenesis has been shown to promote pathological liver growth. However, little is known about the regulatory mechanism of miR-145 in embryonic liver development. In this study, we demonstrate a significant decrease in miR-145 expression during hepatogenesis. We modulate miR-145 expression in zebrafish embryos by injection with a miR-145 mimic or a miR-145 hairpin inhibitor. Altered embryonic liver outgrowth is observed in response to miR-145 expression modulation. We also confirm a critical role of miR-145 in hepatic outgrowth by using whole-mount in situ hybridization. Loss of miR-145 expression in embryos results in hepatic cell proliferation, and vice versa. Furthermore, we demonstrate that GrnA is a target of miR-145 and GrnA-induced MET signaling is also regulated by miR-145 as determined by luciferase reporter assay and gene expression analysis, respectively. In addition, co-injection of GrnA mRNA with miR-145 mimic or MO-GrnA with miR-145 inhibitor restores the liver defects caused by dysregulation of miR-145 expression. In conclusion, our findings suggest an important role of miR-145 in regulating GrnA-dependent hepatic outgrowth in zebrafish embryonic development.

MeSH terms

  • Animals
  • Cell Line
  • Cell Proliferation
  • Gene Expression Regulation, Developmental
  • Hepatocytes / cytology
  • Intercellular Signaling Peptides and Proteins / genetics*
  • Liver / growth & development*
  • MicroRNAs / genetics*
  • Organ Size
  • Signal Transduction
  • Zebrafish / embryology*
  • Zebrafish / genetics
  • Zebrafish Proteins / genetics*

Substances

  • Intercellular Signaling Peptides and Proteins
  • MicroRNAs
  • Mirn145 microRNA, zebrafish
  • Zebrafish Proteins
  • progranulin A, zebrafish

Grants and funding

This research is supported by grant 104-2313-B-001-005 from the Ministry of Science and Technology (MOST) in Taiwan.