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Src family kinases regulate renal epithelial dedifferentiation through activation of EGFR/PI3K signaling

Shougang Zhuang1, Meili Duan, Yan Yan

  • 1Department of Nephrology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China. szhuang@lifespan.org

Journal of Cellular Physiology
|July 23, 2011
PubMed

Insights

Kidney cells dedifferentiate during repair, a process driven by Src family kinases (SFKs) activating the epidermal growth factor receptor (EGFR)/phosphoinositide-3-kinase (PI3K) pathway. This pathway is crucial for renal tubular cell dedifferentiation and outgrowth.

Area of Science:

  • Cell Biology
  • Renal Physiology
  • Molecular Signaling

Background:

  • Dedifferentiation of renal tubular cells is a critical initial step in kidney repair following injury.
  • The molecular mechanisms governing renal proximal tubular cell (RPTC) dedifferentiation remain largely uncharacterized.
  • Understanding these mechanisms is vital for developing therapeutic strategies for acute kidney injury.

Purpose of the Study:

  • To investigate the signaling pathways involved in the dedifferentiation of primary cultured RPTCs.
  • To elucidate the role of specific kinases, including Src, EGFR, AKT, and ERK1/2, in RPTC dedifferentiation.
  • To determine the upstream regulators and downstream effectors of RPTC dedifferentiation.

Main Methods:

  • Primary culture of rat proximal renal tubular cells (RPTCs).
  • Assessment of RPTC dedifferentiation by monitoring vimentin and cytokeratin-18 expression.
  • Pharmacological inhibition of signaling pathways including Src family kinases (SFKs), epidermal growth factor receptor (EGFR), PI3K/AKT, and ERK1/2.
  • Analysis of protein phosphorylation levels (Src, EGFR, AKT, ERK1/2) using Western blotting.
  • Evaluation of RPTC proliferation and migration following pathway inhibition.

Main Results:

  • RPTC dedifferentiation, marked by increased vimentin and decreased cytokeratin-18, occurred within 72 hours of culture.
  • Phosphorylation of Src, EGFR, AKT, and ERK1/2 increased during early culture stages.
  • Inhibition of SFKs or EGFR blocked phosphorylation of downstream kinases (AKT, ERK1/2) and prevented RPTC dedifferentiation.
  • Inactivation of the PI3K/AKT pathway inhibited dedifferentiation, while ERK1/2 pathway inhibition did not.
  • SFK, EGFR, and PI3K/AKT inhibition abrogated RPTC outgrowth, with SFK inhibition also reducing proliferation and migration.

Conclusions:

  • Src family kinases (SFKs) play a pivotal role in mediating RPTC dedifferentiation.
  • SFK activation leads to RPTC dedifferentiation via the epidermal growth factor receptor (EGFR)/phosphoinositide-3-kinase (PI3K) signaling pathway.
  • Targeting SFKs, EGFR, or PI3K/AKT may offer therapeutic potential for enhancing renal repair.

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