Neutrophil elastase enzymatically antagonizes the in vitro action of G-CSF: implications for the regulation of granulopoiesis.
There is evidence that neutrophil production is a balance between the proliferative action of granulocyte-colony-stimulating factor (G-CSF) and a negative feedback from mature neutrophils (the chalone). Two neutrophil serine proteases have been implicated in granulopoietic regulation: pro-proteinase 3 inhibits granulocyte macrophage-colony-forming unit (CFU-GM) growth, and elastase mutations cause cyclic and congenital neutropenia. We further studied the action of the neutrophil serine proteases (proteinase 3, elastase, azurocidin, and cathepsin G) on granulopoiesis in vitro. Elastase inhibited CFU-GM in methylcellulose culture. In serum-free suspension cultures of CD34+ cells, elastase completely abrogated the proliferation induced by G-CSF but not that of GM-CSF or stem cell factor (SCF). The blocking effect of elastase was prevented by inhibition of its enzymatic activity with phenylmethylsulfonyl fluoride (PMSF) or heat treatment. When exposed to enzymatically active elastase, G-CSF, but not GM-CSF or SCF, was rapidly cleaved and rendered inactive. These results support a role for neutrophil elastase in providing negative feedback to granulopoiesis by direct antagonism of G-CSF.
El Ouriaghli
Frank
F
Hematology Branch, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Fujiwara
Hiroshi
H
Melenhorst
J Joseph
JJ
Sconocchia
Giuseppe
G
Hensel
Nancy
N
Barrett
A John
AJ
D000328:Adult; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins / Q000494:pharmacology; D002352:Carrier Proteins / Q000494:pharmacology; D056649:Cathepsin G; D002403:Cathepsins / Q000494:pharmacology; D002478:Cells, Cultured / Q000187:drug effects; D025461:Feedback, Physiological; D016179:Granulocyte Colony-Stimulating Factor / Q000037:antagonists & inhibitors*; D006098:Granulocytes / Q000166:cytology*; D006410:Hematopoiesis / Q000187:drug effects / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D019272:Leukocyte Elastase / Q000494:pharmacology / Q000502:physiology*; D053146:Myeloblastin; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D016188:Receptors, Granulocyte Colony-Stimulating Factor / Q000187:drug effects; D012697:Serine Endopeptidases / Q000494:pharmacology
C062991:AZU1 protein, human; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D002352:Carrier Proteins; D011480:Protease Inhibitors; D016188:Receptors, Granulocyte Colony-Stimulating Factor; D016179:Granulocyte Colony-Stimulating Factor; D010664:Phenylmethylsulfonyl Fluoride; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D019272:Leukocyte Elastase; D053146:Myeloblastin