Cellular growth and tube formation of HTR8/SVneo trophoblast: effects of exogenously added fatty acid-binding protein-4 and its inhibitor

Mol Cell Biochem. 2018 Jan;437(1-2):55-64. doi: 10.1007/s11010-017-3095-9. Epub 2017 Jun 15.


Adequate placental angiogenesis is critical for the establishment of the placental circulation and thus for normal feto-placental growth and development. Fatty acid-binding protein-4 (FABP4) plays a pro-angiogenic role in endothelial cells; however, very little information is available in placental first trimester trophoblast cells. Here we report that exogenously added FABP4 (exo-FABP4) stimulated tube formation (as a measure of in vitro angiogenesis) in HTR8/SVneo trophoblastic cells. HTR-8/SVneo cells were incubated in the presence of exogenously added FABP4 at different concentrations and time points. Cellular growth, proliferation, in vitro tube formation, expression of growth stimulatory-, fatty acid transporters, and angiogenic genes were investigated. Internalization of exo-FABP4 was carried out using immunocytochemistry. Radioactive fatty acid uptake was determined in the presence and absence of FABP4 metabolic inhibitor. Exo-FABP4 (10-100 ng/ml) stimulated proliferation of HTR8/SVneo cells as compared to control. Exo-FABP4 dose dependently increased growth and viability of the cells to the similar extent as done by 50 µM of arachidonic acid. Exo-FABP4-induced tube formation and proliferation were significantly inhibited by FABP4 (BMS309403) inhibitor. Exo-FABP4 stimulated the expression of growth stimulatory genes such as tissue inhibitor of matrix metalloproteinases-1 (TIMP1), insulin-like growth factor 1 (IGF1), and also prokineticin 2 (PROK2), the pro-angiogenic mediators in these cells. In addition, expressions of genes associated with proliferation and differentiation such as sonic hedgehog (SHH) and WNT1 inducible signalling pathway protein 1 (WISP1) were significantly expressed when cells were exposed to exo-FABP4. Our findings reveal a pro-angiogenic role of FABP4 in first trimester placental trophoblast cells and its regulation may have impact in placental physiology.

Keywords: Angiogenesis pathway; FABP4; FABP4 inhibitor; HTR8/SVneo cells; IGF1; Immunofluorescence; NOTCH signalling; Thymidine assay; Tube formation.

MeSH terms

  • Biphenyl Compounds / pharmacology*
  • Cell Differentiation / drug effects*
  • Cell Line, Transformed
  • Fatty Acid-Binding Proteins* / antagonists & inhibitors
  • Fatty Acid-Binding Proteins* / pharmacology
  • Humans
  • Neovascularization, Physiologic / drug effects*
  • Pyrazoles / pharmacology*
  • Signal Transduction / drug effects*
  • Trophoblasts / cytology
  • Trophoblasts / metabolism*


  • 2-(2'-(5-ethyl-3,4-diphenyl-1H-pyrazol-1-yl)biphenyl-3-yloxy)acetic acid
  • Biphenyl Compounds
  • FABP4 protein, human
  • Fatty Acid-Binding Proteins
  • Pyrazoles