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Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN

Karmveer Singh1, Pallab Maity1, Linda Krug1

  • 1Department of Dermatology and Allergic Diseases, University of Ulm, Ulm, Germany Aging Research Center (ARC), Ulm, Germany.

EMBO Molecular Medicine
|December 19, 2014
PubMed

Insights

Mitochondrial superoxide anions suppress Insulin-like Growth Factor 1 (IGF-1) signaling, impacting skin aging. Inhibiting phosphatases PTP1B and PTEN reverses this resistance, offering potential therapeutic targets.

Area of Science:

  • Molecular Biology
  • Aging Research
  • Biochemistry

Background:

  • The Insulin-like Growth Factor 1 (IGF-1) signaling pathway is crucial for longevity, metabolism, tissue homeostasis, and cancer.
  • Regulation of IGF-1 signaling involves a complex interplay of kinases and phosphatases, with mechanisms not fully elucidated.
  • Mitochondrial dysfunction, specifically superoxide anion (O2∙-) accumulation, is implicated in aging and disease.

Purpose of the Study:

  • To investigate the impact of mitochondrial superoxide anions (O2∙-) on IGF-1 signaling.
  • To identify the molecular mechanisms by which O2∙- suppresses IGF-1 signaling.
  • To explore the potential of targeting key phosphatases for therapeutic intervention in aging-related pathologies.

Main Methods:

  • In vitro and in vivo studies using a murine aging model.
  • Chemical inhibition of mitochondrial complex I and genetic silencing of mitochondrial Sod2 to induce O2∙- accumulation.
  • Analysis of fibroblast proliferation, translation initiation factors, collagen expression, and phosphatase activity (PTP1B, PTEN).
  • Genetic and pharmacologic inhibition of PTP1B and PTEN.

Main Results:

  • Accumulation of mitochondrial superoxide anions (O2∙-) suppressed IGF-1 signaling.
  • This suppression led to reduced murine dermal fibroblast proliferation, altered translation initiation, and decreased collagen expression, characteristic of skin aging.
  • O2∙- activated phosphatases PTP1B and PTEN, which dephosphorylated the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate, dampening IGF-1 signaling.
  • Inhibition of PTP1B and PTEN reversed O2∙--induced IGF-1 resistance and ameliorated the skin aging phenotype.

Conclusions:

  • Mitochondrial superoxide anions (O2∙-) are key regulators that suppress IGF-1 signaling through PTP1B and PTEN activation.
  • This O2∙--mediated suppression contributes to the molecular hallmarks of skin aging.
  • Targeting O2∙-, PTP1B, and PTEN represents a promising therapeutic strategy to combat IGF-1 resistance and related aging pathologies.
Keywords:
IGF‐1ageingphosphatasereactive oxygen speciessuperoxide anions

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