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Caveolin-1 in mesangial cells suppresses MAP kinase activation and cell proliferation induced by bFGF and PDGF

Yutaka Fujita1, Shoichi Maruyama, Hiroshi Kogo

  • 1Division of Clinical Immunology, Department of Internal Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan. fyutaka@med.nagoya-u.ac.jp

Kidney International
|October 22, 2004
PubMed
Abstract

Insights

Overexpressing caveolin-1 in mesangial cells inhibits the MAP kinase pathway and cell proliferation. This suggests caveolin-1 gene therapy could treat mesangioproliferative nephritis by blocking growth factors.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Renal Disease Research

Background:

  • Caveolin-1 is a key protein in caveolae, regulating cellular signaling.
  • Mesangial cells, crucial in renal function, possess abundant caveolae.
  • Modulating caveolin-1 levels may control mesangial cell proliferation, a factor in kidney diseases.

Purpose of the Study:

  • To investigate the effect of caveolin-1 on the Raf-MEK-MAP kinase pathway.
  • To determine caveolin-1's impact on mesangial cell proliferation stimulated by growth factors.
  • To explore caveolin-1 as a potential therapeutic target for renal diseases.

Main Methods:

  • Transfection of caveolin-1 cDNA into rat primary mesangial cells and MES13 cells.
  • Analysis of Raf-extracellular signal-regulated protein kinase (ERK) kinase (MEK)-mitogen-activated protein (MAP) kinase pathway activation via immunofluorescence and Western blot.
  • Assessment of cell proliferation in response to basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF).

Main Results:

  • Overexpression of caveolin-1 suppressed bFGF- and PDGF-induced activation of Raf-1, MEK-1/2, and MAP kinase.
  • Caveolin-1 overexpression inhibited mesangial cell proliferation stimulated by bFGF and PDGF.
  • The inhibitory effect was specific to the Raf-MEK-MAP kinase pathway, as Smad2 activation by TGF-beta was unaffected.

Conclusions:

  • Caveolin-1 overexpression in mesangial cells effectively suppresses MAP kinase activation and cell proliferation.
  • bFGF and PDGF are key cytokines in mesangioproliferative nephritis.
  • Introducing a caveolin-1 expression vector presents a potential therapeutic strategy for mesangioproliferative nephritis.

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