Eosinophil major basic protein: first identified natural heparanase-inhibiting protein.

Abstract

BACKGROUND:

Heparanase and eosinophils are involved in several diseases, including inflammation, cancer, and angiogenesis.

OBJECTIVE:

We sought to determine whether eosinophils produce active heparanase.

METHODS:

Human peripheral blood eosinophils were isolated by immunoselection and tested for heparanase protein (immunocytochemistry, Western blot), mRNA (RT-PCR) and activity (Na(2)[(35)S]O(4)-labeled extracellular matrix degradation) before and after activation. Heparanase intracellular localization (confocal laser microscopy) and ability to bind to eosinophil major basic protein (MBP) were also evaluated (immunoprecipitation). A model of allergic peritonitis resulting in eosinophilia was induced in TNF knockout and wild-type mice for in vivo studies.

RESULTS:

Eosinophils synthesized heparanase mRNA and contained heparanase in the active (50-kd) and latent (65-kd) forms. Heparanase partially co-localized with and was bound to MBP. No heparanase enzymatic activity was detected in eosinophils resting or activated with various agonists, including GM-CSF/C5a. Eosinophil lysates and MBP inhibited recombinant heparanase activity in a concentration-dependent manner (100%, 2 x 10(-7) mol/L). Eosinophil peroxidase and eosinophil cationic protein, but not myelin basic protein or compound 48/80, partially inhibited heparanase activity. Poly-l-arginine at very high concentrations caused an almost complete inhibition. In allergic peritonitis, heparanase activity in the peritoneal fluid inversely correlated with eosinophil number.

CONCLUSIONS:

MBP is the first identified natural heparanase-inhibiting protein. Its presence in the eosinophil granules might indicate a protective function of these cells in diseases associated with inflammation and cancer progression.

• Authors: Vladislav Temkin, Helena Aingorn, Ilaria Puxeddu, Orit Goldshmidt, Eyal Zcharia, Gerald J Gleich, Israel Vlodavsky, Francesca Levi-Schaffer
• Journal: The Journal of allergy and clinical immunology (J Allergy Clin Immunol) Vol. 113 Issue 4 Pg. 703-9 (Apr 2004) ISSN: 0091-6749 [Print] United States
• PMID: 15100677 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Blood Proteins
• Eosinophil Granule Proteins
• RNA, Messenger
• Ribonucleases
• Heparin Lyase

Topics

• Animals
• Blood Proteins (physiology)
• Cells, Cultured
• Cytoplasmic Granules (metabolism)
• Eosinophil Granule Proteins
• Eosinophils (metabolism, pathology, physiology)
• Heparin Lyase (antagonists & inhibitors, genetics, metabolism)
• Humans
• Hypersensitivity (complications)
• Leukocyte Count
• Mice
• Peritonitis (etiology, pathology)
• RNA, Messenger (metabolism)
• Ribonucleases (physiology)
• Tissue Distribution