PTB-associated splicing factor inhibits IGF-1-induced VEGF upregulation in a mouse model of oxygen-induced retinopathy

Cell Tissue Res. 2015 May;360(2):233-43. doi: 10.1007/s00441-014-2104-5. Epub 2015 Feb 1.

Abstract

Pathological retinal neovascularization, including retinopathy of prematurity and age-related macular degeneration, is the most common cause of blindness worldwide. Insulin-like growth factor-1 (IGF-1) has a direct mitogenic effect on endothelial cells, which is the basis of angiogenesis. Vascular endothelial growth factor (VEGF) activation in response to IGF-1 is well documented; however, the molecular mechanisms responsible for the termination of IGF-1 signaling are still not completely elucidated. Here, we show that the polypyrimidine tract-binding protein-associated splicing factor (PSF) is a potential negative regulator of VEGF expression induced by IGF stimulation. Functional analysis demonstrated that ectopic expression of PSF inhibits IGF-1-stimulated transcriptional activation and mRNA expression of the VEGF gene, whereas knockdown of PSF increased IGF-1-stimulated responses. PSF recruited Hakai to the VEGF transcription complex, resulting in inhibition of IGF-1-mediated transcription. Transfection with Hakai siRNA reversed the PSF-mediated transcriptional repression of VEGF gene transcription. In summary, these results show that PSF can repress the transcriptional activation of VEGF stimulated by IGF-1 via recruitment of the Hakai complex and delineate a novel regulatory mechanism of IGF-1/VEGF signaling that may have implications in the pathogenesis of neovascularization in ocular diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Disease Models, Animal
  • Female
  • Insulin-Like Growth Factor I / genetics
  • Insulin-Like Growth Factor I / metabolism*
  • Male
  • Mice
  • Oxygen / adverse effects*
  • Oxygen / pharmacology
  • PTB-Associated Splicing Factor
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Retinal Neovascularization / chemically induced
  • Retinal Neovascularization / genetics
  • Retinal Neovascularization / metabolism*
  • Retinal Neovascularization / pathology
  • Signal Transduction / drug effects*
  • Signal Transduction / genetics
  • Up-Regulation / drug effects*
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • PTB-Associated Splicing Factor
  • RNA-Binding Proteins
  • Vascular Endothelial Growth Factor A
  • insulin-like growth factor-1, mouse
  • vascular endothelial growth factor A, mouse
  • Insulin-Like Growth Factor I
  • Oxygen