Neutrophil elastase enzymatically antagonizes the in vitro action of G-CSF: implications for the regulation of granulopoiesis

Abstract

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

Successful transplantation of peripheral blood stem cells mobilized by chemotherapy and a single dose of pegylated G-CSF in patients with multiple myeloma

“…10,[16][17][18] When the number of granulocytes increases, pegfilgrastim is eliminated by cellular uptake via the G-CSF receptor and intracellular degradation, as well as by cleavage through neutrophil elastase. 19,20 Thus, the rise of leukocytes leads to a rapid clearance of G-CSF in the pegfilgrastim group, which then may result in less effective mobilization of CD34 þ cells. The self-limiting effect of pegfilgrastim may not be relevant in shortening the duration of neutropenia, but may be so for effective stem cell mobilization.…”

Proteinase 3 and neutrophil elastase enhance inflammation in mice by inactivating antiinflammatory progranulin

“…All 3 NSPs are implicated in antimicrobial defense by degrading engulfed microorganisms inside the phagolysosomes of neutrophils (4)(5)(6)(7)(8). Among many other functions ascribed to these enzymes, PR3 and NE were also suggested to play a fundamental role in granulocyte development in the bone marrow (9)(10)(11).…”

Human neutrophil elastase is not a target for therapy in chronic myeloid leukaemia

“…1,2 The G-CSF receptor is not digested; instead HNE targets G-CSF protein exerting a negative feedback on cytokine activity. 1 High plasma levels of HNE 2 and low G-CSF 3 have been reported in CML. Moreover, it is known that Ph þ cells can invoke autocrine G-CSF cytokine production.…”

“…1 The efforts to decrease the risk of graft-versus-host disease (GVHD) as a major cause of transplant-related mortality by depleting T cells from the graft resulted in an increased incidence of CML relapse. 2 These observations revealed that donor T cells representing the mediators of GVHD are also capable of inducing therapeutic HNE plasma levels pre-IM treatment.…”

“…1 PGP proteases, including HNE, normally provide negative feedback of granulopoiesis by controlling the availability of granulocyte colony-stimulating factor (G-CSF) proportionate to the relative abundance of mature granulocytes that are greatly elevated in number as a clinical feature of chronic myeloid leukaemia (CML).…”