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Isolation of Murine Peritoneal Macrophages to Carry Out Gene Expression Analysis Upon Toll-like Receptors Stimulation
08:21

Isolation of Murine Peritoneal Macrophages to Carry Out Gene Expression Analysis Upon Toll-like Receptors Stimulation

Published on: April 29, 2015

Proteolytic cleavage and activation of pro-macrophage-stimulating protein by resident peritoneal macrophage membrane

M H Wang1, A Skeel, E J Leonard

  • 1Immunopathology Section, National Cancer Institute, National Institutes of Health, Frederick, Maryland 21702, USA.

The Journal of Clinical Investigation
|February 1, 1996
PubMed

Insights

Macrophage stimulating protein (MSP) circulates as inactive pro-MSP. Target cells, like macrophages, cleave pro-MSP, controlling its activity through proteolysis.

Area of Science:

  • Biochemistry
  • Cell Biology
  • Immunology

Background:

  • Macrophage stimulating protein (MSP) is crucial for immune responses.
  • It is secreted in an inactive precursor form, pro-MSP.
  • Activation to active MSP requires cleavage at a specific peptide bond.

Purpose of the Study:

  • To determine the circulating form of MSP in blood.
  • To investigate the proteolytic activation of pro-MSP by target cells.
  • To understand the role of macrophages in MSP regulation.

Main Methods:

  • Immunoaffinity purification of serum MSP followed by Western blot analysis.
  • Incubation of radiolabeled pro-MSP with murine peritoneal macrophages.
  • Assessment of protease inhibitor effects on pro-MSP cleavage.
  • Analysis of pro-MSP proteolytic activity on macrophage membranes and in culture fluids.

Main Results:

  • Circulating MSP exists exclusively as inactive pro-MSP.
  • Macrophages cleave pro-MSP, primarily into inactive fragments.
  • Macrophage membranes possess pro-MSP proteolytic activity.
  • Soybean trypsin inhibitor modulated pro-MSP cleavage, sometimes enhancing mature MSP formation.

Conclusions:

  • The inactive pro-MSP is the predominant circulating form.
  • Target cells, specifically macrophages, play a key role in regulating MSP activity.
  • Proteolytic cleavage of pro-MSP by target cells controls its biological activation or inactivation.

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