Neuropilin-1 aggravates liver cirrhosis by promoting angiogenesis via VEGFR2-dependent PI3K/Akt pathway in hepatic sinusoidal endothelial cells

EBioMedicine. 2019 May:43:525-536. doi: 10.1016/j.ebiom.2019.04.050. Epub 2019 May 3.

Abstract

Background: We have revealed that neuropilin-1 (NRP-1) promoted hepatic stellate cell activation and liver fibrosis through its profibrogenic signalling pathways. However, the role of NRP-1 in angiogenesis in hepatic sinusoidal endothelial cells (HSECs) during liver cirrhosis remains unclear.

Methods: The correlation between NRP-1 expression and angiogenesis was evaluated in both human and murine cirrhotic liver tissues by immunohistochemical staining, quantitative real-time PCR, and western blotting. In addition, the role and mechanism of NRP-1 in regulating VEGFR2-dependent angiogenesis was identified in endothelial cells (ECs) in vitro. Moreover, liver histocultures were used to test the therapeutic effect of NRP-1 blocking in liver fibrosis.

Findings: Higher expression of NRP-1 in HSECs was detected, which was positively correlated with angiogenesis in liver cirrhosis. In vitro, NRP-1 knockdown suppressed the expression and activation of VEGFR2, accompanied by reduced ability of the vascular tube formation and the migration of ECs. Conversely, NRP-1 overexpression upregulated VEGFR2, promoted tube formation, and the migration of ECs. Mechanistically, NRP-1 modulated the expression of VEGFR2 by regulating FAK and its kinase activity. Furthermore, NRP-1 promoted VEGFR2-dependent angiogenesis via the PI3K/Akt pathway in HSECs. Blocking NRP-1 function reduced intrahepatic angiogenesis and fibrosis-associated factors in the in vitro liver histocultures.

Interpretation: NRP-1 promotes angiogenesis by upregulating the expression and activation of VEGFR2 through the PI3K/Akt signalling pathway in liver cirrhosis. This study highlights the possibility of therapeutically targeting NRP-1 for the treatment of cirrhosis. FUND: National Natural Science Foundation of China (No. 81570551; 81770607; 81600469; 81401868), Key Research project of Shandong Province (No. 2016GSF201008; 2017GSF218053), Natural Science Foundation of Shandong Province (No. ZR2017MH102), National Science and Technology Major Project of China (No. 2018ZX10302206-001-006).

Keywords: Cirrhosis; Hepatic sinusoidal endothelial cells; Intrahepatic angiogenesis; Neuropilin-1; Vascular growth factor receptor 2.

MeSH terms

  • Animals
  • Cell Line
  • Endothelial Cells / metabolism*
  • Gene Expression
  • Humans
  • Liver Cirrhosis / etiology*
  • Liver Cirrhosis / metabolism*
  • Liver Cirrhosis / pathology
  • Mice
  • Models, Biological
  • Neovascularization, Pathologic / genetics
  • Neovascularization, Pathologic / metabolism
  • Neuropilin-1 / genetics*
  • Neuropilin-1 / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Signal Transduction*
  • Tissue Culture Techniques
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism*

Substances

  • Neuropilin-1
  • Phosphatidylinositol 3-Kinases
  • Vascular Endothelial Growth Factor Receptor-2
  • Proto-Oncogene Proteins c-akt