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

• Published in: Journal of allergy and clinical immunology Vol. 113; no. 4; pp. 703 - 709
• Main Authors: Temkin, Vladislav, Aingorn, Helena, Puxeddu, Ilaria, Goldshmidt, Orit, Zcharia, Eyal, Gleich, Gerald J, Vlodavsky, Israel, Levi-Schaffer, Francesca
• Format: Journal Article
• Language: English
• Published: New York, NY Mosby, Inc 01-04-2004; Elsevier; Elsevier Limited
• Subjects: allergic peritonitis; Angiogenesis; Animals; Biological and medical sciences; Blood Proteins - physiology; Cancer; Cells, Cultured; Cytoplasmic Granules - metabolism; Enzymes; Eosinophil Granule Proteins; eosinophils; Eosinophils - metabolism; Eosinophils - pathology; Eosinophils - physiology; fibrosis; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Heparanase; Heparin Lyase - antagonists & inhibitors; Heparin Lyase - genetics; Heparin Lyase - metabolism; Humans; Hypersensitivity - complications; Immunopathology; inflammation; Leukocyte Count; major basic protein; Medical sciences; Melanoma; metastasis; Mice; Microscopy; Peritonitis - etiology; Peritonitis - pathology; Proteins; Ribonucleases - physiology; RNA, Messenger - metabolism; Studies; Tissue Distribution; KO; EPO; angiogenesis; eosinophils; HS; ECM; major basic protein; ECP; inflammation; metastasis; Heparanase; fibrosis; MBP; WT; allergic peritonitis; Allergy; Immunopathology; Granulocyte; Inflammation; Malignant tumor; Metastasis; Eosinophil; Angiogenesis; Immunology; Basic protein; Abdominal disease; Fibrosis; Neovascularization; Peritonitis
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/j.jaci.2003.11.038

Heparanase and eosinophils are involved in several diseases, including inflammation, cancer, and angiogenesis.
We sought to determine whether eosinophils produce active heparanase.
Human peripheral blood eosinophils were isolated by immunoselection and tested for heparanase protein (immunocytochemistry, Western blot), mRNA (RT-PCR) and activity (Na2[35S]O4-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.
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%, 2×10–7 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.
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.