Premium
Constitutive and regulated expression of platelet basic protein in human monocytes
Author(s) -
ElGedaily Ahmed,
Schoedon Gabriele,
Schneemann Markus,
Schaffner Andreas
Publication year - 2004
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.0603288
Subject(s) - biology , monocyte , microbiology and biotechnology , platelet , expression (computer science) , immunology , programming language , computer science
Platelet basic protein (PBP) and several of its derivatives are known for their broad range of functions as signaling molecules and cationic antimicrobial peptides and were considered hitherto megakaryocyte‐ and platelet‐specific. In search of glucocorticoid‐regulated antimicrobial systems of monocytes, we found a 15‐fold down‐regulation of PBP mRNA by differential display. Regulation was confirmed in vivo even at low prednisone doses. Quantitative mRNA analyses confirmed down‐regulation also for platelets. Western blotting and immunostains showed down‐regulation at the protein level. Pro‐PBP derivatives were in the size range of 7.5‐14 kD and in immunostains, gave granular cytoplasmatic patterns. Interleukin (IL)‐4 and IL‐10 induced a similar down‐regulation. Phagocytosis resulted in an increase of smaller derivatives in the range of 7.5 kD. Stimulation with interferon‐γ and lipopolysaccharide did decrease expression of PBP and affected derivatization. Expression of PBP and its derivatives is not restricted to the megakaryocytic cell lineage. PBP and some of its derivatives might contribute to the antimicrobial armamentarium of mononuclear phagocytes or have monokine functions. Our studies define PBPs as one among the many immunosuppressive targets of glucocorticoids.