Cholesterol is obligatory for polarization and chemotaxis but not for endocytosis and associated signaling from chemoattractant receptors in human neutrophils

J Biomed Sci. 2008 Jul;15(4):441-61. doi: 10.1007/s11373-008-9239-x. Epub 2008 Mar 3.

Abstract

Plasma membrane cholesterol is critical for neutrophil chemotaxis, although how cholesterol affects chemotactic signaling pathway has not been clearly delineated. Here we demonstrate that cholesterol was absolutely required for polarized redistribution of key chemotactic mediators in human neutrophils in response to all chemoattractants tested (fMet-Leu-Phe, and the chemokines CXCL1, CXCL8 and CXCL12). In particular, PI3K and phosphatidylinositol-3,4,5 triphosphate (PIP(3)) failed to accumulate at the front and phosphatase and tensin homolog (PTEN) at the back of chemoattractant-stimulated neutrophils after cholesterol depletion. Cholesterol depletion did not affect early chemoattractant signaling events such as G-protein activation, intracellular calcium flux or G-protein-independent endocytosis-linked signaling, including the activation of mitogen-activated protein kinase (MAPK), Hck and Fgr transduced by beta-arrestin. During cell polarization, F-actin assemblies redistributed the cholesterol-rich microdomains and cytoskeleton-anchored proteins, including CD16 and CD44 from the leading edge. These data suggest that spatial polarization of chemotactic mediators is orchestrated by protein:protein interactions that organize cholesterol-rich domains of the plasma membrane.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Actins / physiology
  • Cell Polarity*
  • Chemotaxis*
  • Cholesterol / physiology*
  • Endocytosis
  • Humans
  • Membrane Microdomains / metabolism
  • Membrane Proteins / metabolism
  • Neutrophils / chemistry
  • Neutrophils / physiology*
  • Receptors, Formyl Peptide / metabolism*
  • Signal Transduction

Substances

  • Actins
  • Membrane Proteins
  • Receptors, Formyl Peptide
  • Cholesterol