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Gremlin aggravates hyperglycemia-induced podocyte injury by a TGFβ/smad dependent signaling pathway

Guiying Li1, Ying Li, Shuxia Liu

  • 1Department of Nephrology, Third Hospital, Hebei Medical University, Shijiazhuang, 050051, China.

Journal of Cellular Biochemistry
|April 5, 2013
PubMed

Insights

Gremlin protein, elevated in diabetic kidneys, injures podocytes via TGFβ1/Smad signaling. Reducing gremlin may protect against diabetic nephropathy.

Area of Science:

  • Nephrology
  • Molecular Biology
  • Cell Biology

Background:

  • Diabetic nephropathy (DN) is characterized by podocyte injury.
  • Gremlin, a bone morphogenic protein (BMP) antagonist, is elevated in diabetic kidney tissues.
  • Understanding gremlin's role in podocyte injury is crucial for DN treatment.

Purpose of the Study:

  • To investigate the role of gremlin in high glucose-induced podocyte injury.
  • To elucidate the signaling pathways involved in gremlin-mediated podocyte damage.
  • To assess the therapeutic potential of targeting gremlin in DN.

Main Methods:

  • Cultured mouse podocytes under high glucose conditions.
  • Assessed gremlin expression using confocal microscopy.
  • Utilized recombinant gremlin, gremlin1 siRNA, and specific pathway inhibitors (smad2/3 siRNA, SB431542).
  • Measured podocyte apoptosis via TUNEL assay and key podocyte markers (nephrin, synaptopodin).

Main Results:

  • Gremlin expression was significantly upregulated in podocytes cultured in high glucose.
  • Gremlin treatment decreased nephrin and synaptopodin expression and altered their localization.
  • Knockdown of gremlin1 or smad2/3, and TGFβ receptor inhibition, attenuated podocyte injury.
  • Inhibition of canonical TGF-β signaling blocked gremlin-induced podocyte damage.

Conclusions:

  • Gremlin is upregulated in high glucose conditions and directly contributes to podocyte injury.
  • Gremlin likely mediates podocyte injury through the canonical TGFβ1/Smad signaling pathway.
  • Targeting gremlin, possibly via siRNA, shows potential for attenuating podocyte injury in diabetic nephropathy.
Keywords:
GREMLIN1INJURY, MOUSE PODOCYTESMADTRANSFORMING GROWTH FACTOR BETA1

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