Get access

Insulin growth factor signaling mediates neuron-like differentiation of adipose tissue-derived stem cells

Authors

  • Hongxiu Ning,

    1. Knuppe Molecular Urology Laboratory Department of Urology, School of Medicine, University of California San Francisco, CA 94143-0738, USA
      Tel: +1 415 476 3800
      Fax: +1 415 476 3803
    Search for more papers by this author
  • Guiting Lin,

    1. Knuppe Molecular Urology Laboratory Department of Urology, School of Medicine, University of California San Francisco, CA 94143-0738, USA
      Tel: +1 415 476 3800
      Fax: +1 415 476 3803
    Search for more papers by this author
  • Thomas Fandel,

    1. Knuppe Molecular Urology Laboratory Department of Urology, School of Medicine, University of California San Francisco, CA 94143-0738, USA
      Tel: +1 415 476 3800
      Fax: +1 415 476 3803
    Search for more papers by this author
  • Lia Banie,

    1. Knuppe Molecular Urology Laboratory Department of Urology, School of Medicine, University of California San Francisco, CA 94143-0738, USA
      Tel: +1 415 476 3800
      Fax: +1 415 476 3803
    Search for more papers by this author
  • Tom F. Lue,

    1. Knuppe Molecular Urology Laboratory Department of Urology, School of Medicine, University of California San Francisco, CA 94143-0738, USA
      Tel: +1 415 476 3800
      Fax: +1 415 476 3803
    Search for more papers by this author
  • Ching-Shwun Lin

    Corresponding author
    1. Knuppe Molecular Urology Laboratory Department of Urology, School of Medicine, University of California San Francisco, CA 94143-0738, USA
      Tel: +1 415 476 3800
      Fax: +1 415 476 3803
    Search for more papers by this author

✉ E-mail: clin@urology.ucsf.edu

Abstract

Abstract Our previous study showed that adipose tissue-derived stem cells (ADSC) could be induced by isobutylmethylxanthine (IBMX) to differentiate into neuron-like cells. In the present study, ADSC were treated with IBMX in the presence or in the absence of each of eight specific inhibitors of different signaling pathways (JAK/STAT, PKA, PI3K, MEK, Wnt/Frizzled, ERK/MAPK, TGF-β, and insulin growth factor [IGF]-I). PPP, a specific inhibitor of IGF-I signaling, was the only inhibitor that showed significant inhibition of IBMX-induced ADSC neuronal differentiation, as determined by changes in cell morphology in the initial screening. Further examination by immunofluorescence staining showed that the neuronal marker, β-III-tubulin, was highly induced in IBMX-treated ADSC, and the induction was significantly suppressed by PPP. Western blotting, followed by densitometry showed that PPP suppressed IBMX-induced β-III-tubulin expression by 43%, 88%, and 84% when used to treat the cells for 1, 3, and 24 hr, respectively. Treatment of ADSC with IBMX also led to the phosphorylation of IGF-I receptor at tyrosine 1136 (Y1136), as determined by immunofluorescence staining with an antibody that reacts specifically with Y1136. This effect was also abrogated by PPP. Thus, the IBMX-induced neuron-like differentiation of ADSC is mediated by IGF signaling through the phosphorylation of IGF-IR at Y1136.

Ancillary