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Published on: August 22, 2010

Mechanisms of the proteinuria induced by Rho GTPases

Liming Wang1, Mathew J Ellis, Jose A Gomez

  • 1Division of Nephrology, Department of Medicine, Duke University and Durham VA Medical Centers, Durham, North Carolina 27710, USA.

Kidney International
|January 27, 2012
PubMed

Insights

Rho A is crucial for maintaining kidney filtration barrier integrity. Overactivation of Rho A in podocytes leads to injury, while inhibiting it causes cytoskeletal disruption, highlighting its essential role.

Area of Science:

  • Nephrology
  • Cell Biology
  • Molecular Biology

Background:

  • Podocytes are vital for glomerular filtration barrier integrity.
  • Rho family GTPases regulate podocyte function.
  • Rho A's specific role in podocyte biology requires elucidation.

Purpose of the Study:

  • To investigate the role of Rho A in podocyte biology using transgenic mouse models.
  • To determine the effects of constitutively active and dominant-negative Rho A on podocyte function and glomerular integrity.

Main Methods:

  • Generation of doxycycline-inducible transgenic mice expressing V14 Rho (constitutively active) or N19 Rho (dominant-negative) in podocytes.
  • Assessment of albuminuria, foot process effacement, and actin cytoskeleton integrity.
  • Measurement of synaptopodin, nephrin mRNA and protein levels, and podocyte apoptosis.

Main Results:

  • Induction of V14 Rho or N19 Rho in podocytes caused albuminuria and foot process effacement.
  • V14 Rho enhanced actin polymerization, reduced nephrin levels, promoted apoptosis, and decreased endogenous Rho A.
  • N19 Rho disrupted stress fibers but did not affect nephrin or Rho A levels or cause apoptosis.

Conclusions:

  • Rho A is essential for maintaining basal glomerular filtration barrier integrity.
  • Enhanced Rho A activity above basal levels promotes podocyte injury.
  • Modulating Rho A activity has distinct effects on podocyte structure and function.

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