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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
Summary
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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