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Apoptosis in podocytes induced by TGF-beta and Smad7

M Schiffer1, M Bitzer, I S Roberts

  • 1Division of Nephrology, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

The Journal of Clinical Investigation
|September 19, 2001
PubMed

Insights

Focal segmental glomerulosclerosis (FSGS) involves podocyte depletion. This study reveals Smad7 amplifies TGF-beta1-induced podocyte apoptosis, offering a new mechanism for FSGS progression.

Area of Science:

  • Nephrology
  • Molecular Biology
  • Cell Biology

Background:

  • Focal segmental glomerulosclerosis (FSGS) is characterized by podocyte depletion, a hallmark of progressive glomerular diseases.
  • Understanding the mechanisms of podocyte loss is crucial for developing effective treatments for FSGS.

Purpose of the Study:

  • To investigate the role of Smad7 in TGF-beta1-induced podocyte apoptosis in the context of progressive glomerulosclerosis.
  • To elucidate the signaling pathways involved in TGF-beta1 and Smad7-mediated podocyte apoptosis.

Main Methods:

  • Utilized TGF-beta1 transgenic mice and cultured murine podocytes.
  • Assessed podocyte apoptosis, Smad7 expression, p38 MAP kinase, caspase-3, and NF-kappaB activation.

Main Results:

  • Podocyte apoptosis and depletion occur early in progressive glomerulosclerosis in TGF-beta1 transgenic mice.
  • Smad7 is induced in damaged podocytes and amplifies TGF-beta1-induced apoptosis.
  • Smad7 inhibits NF-kappaB, while TGF-beta1-mediated apoptosis requires p38 MAP kinase and caspase-3.

Conclusions:

  • Smad7 acts as an amplifier of TGF-beta1-induced podocyte apoptosis.
  • This study identifies a novel pathomechanism for podocyte depletion in progressive glomerulosclerosis.

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