Macrophage colony-stimulating factor restored chemotherapy-induced granulocyte dysfunctions: role of IL-8 production by monocytes

Shp2 plays an important role in acute cigarette smoke-mediated lung inflammation

Cigarette smoke (CS), the major cause of chronic obstructive pulmonary disease, contains a variety of oxidative components that were implicated in the regulation of Src homology domain 2-containing protein tyrosine phosphatase 2 (Shp2) activity. However, the contribution of Shp2 enzyme to chronic obstructive pulmonary disease pathogenesis remains unclear. We investigated the role of Shp2 enzyme in blockading CS-induced pulmonary inflammation. Shp2 levels were assessed in vivo and in vitro. Mice (C57BL/6) or pulmonary epithelial cells (NCI-H292) were exposed to CS or cigarette smoke extract (CSE) to induce acute injury and inflammation. Lungs of smoking mice showed increased levels of Shp2, compared with those of controls. Treatment of lung epithelial cells with CSE showed elevated levels of Shp2 associated with the increased release of IL-8. Selective inhibition or knockdown of Shp2 resulted in decreased IL-8 release in response to CSE treatment in pulmonary epithelial cells. In comparison with CS-exposed wild-type mice, selective inhibition or conditional knockout of Shp2 in lung epithelia reduced IL-8 release and pulmonary inflammation in CS-exposed mice. In vitro biochemical data correlate CSE-mediated IL-8 release with Shp2-regulated epidermal growth factor receptor/Grb-2-associated binders/MAPK signaling. Our data suggest an important role for Shp2 in the pathological alteration associated with CS-mediated inflammation. Shp2 may be a potential target for therapeutic intervention for inflammation in CS-induced pulmonary diseases.

Expression of a novel recombinant stem cell factor/macrophage colony-stimulating factor fusion protein in baculovirus-infected insect cells

A novel human stem cell factor (SCF)/macrophage colony-stimulating factor (M-CSF) fusion protein gene was constructed, in which the coding regions of human SCF cDNA (1-165aa) and the truncated M-CSF cDNA (1-149aa) were connected by a linker sequence encoding a short peptide GGGGSGGGGSGG. The SCF/M-CSF gene was cloned into baculovirus transfer vector pVL1392 under the control of polyhedrin promoter and expressed in the Sf9 cells (Spodoptera frugiperda). SDS-PAGE and Western blot analysis showed that the purified fusion protein was a homodimer with a molecular weight about 84kDa under non-reducing conditions or a monomer about 42kDa under reducing conditions. The specific activity of rhSCF/M-CSF was 17 times as high as that of monomeric rhSCF to stimulate the proliferation of TF-1 cell. The results of macrophages colony-forming (CFU-M) assay performed with human bone marrow mononuclear cells demonstrated that rhSCF/M-CSF was more potent in promoting CFU-M than the equimolar of SCF, M-CSF or that of two cytokines mixture.

Design of Recombinant Stem Cell Factor–macrophage Colony Stimulating Factor Fusion Proteins and their Biological Activity In Vitro

Stem cell factor (SCF) and macrophage colony stimulating factor (M-CSF) can act in synergistic way to promote the growth of mononuclear phagocytes. SCF-M-CSF fusion proteins were designed on the computer using the Homology and Biopolymer modules of the software packages InsightII. Several existing crystal structures were used as templates to generate models of the complexes of receptor with fusion protein. The structure rationality of the fusion protein incorporated a series of flexible linker peptide was analyzed on InsightII system. Then, a suitable peptide GGGGSGGGGSGG was chosen for the fusion protein. Two recombinant SCF-M-CSF fusion proteins were generated by construction of a plasmid in which the coding regions of human SCF (1-165aa) and M-CSF (1-149aa) cDNA were connected by this linker peptide coding sequence followed by subsequent expression in insect cell. The results of Western blot and activity analysis showed that these two recombinant fusion proteins existed as a dimer with a molecular weight of approximately 84 KD under non-reducing conditions and a monomer of approximately 42 KD at reducing condition. The results of cell proliferation assays showed that each fusion protein induced a dose-dependent proliferative response. At equimolar concentration, SCF/M-CSF was about 20 times more potent than the standard monomeric SCF in stimulating TF-1 cell line growth, while M-CSF/SCF was 10 times of monomeric SCF. No activity difference of M-CSF/SCF or SCF/M-CSF to M-CSF (at same molar) was found in stimulating the HL-60 cell linear growth. The synergistic effect of SCF and M-CSF moieties in the fusion proteins was demonstrated by the result of clonogenic assay performed with human bone mononuclear, in which both SCF/M-CSF and M-CSF/SCF induced much higher number of CFU-M than equimolar amount of SCF or M-CSF or that of two cytokines mixture.

Mirimostim (macrophage colony-stimulating factor; M-CSF) improves chemotherapy-induced impaired natural killer cell activity, Th1/Th2 balance, and granulocyte function

The purpose of this study was to clarify the effects of mirimostim (macrophage colony-stimulating factor; M-CSF) on immunological functions after chemotherapy. The percentage of natural killer (NK) cells in peripheral blood mononuclear cells (PBMCs), NK cell activity, T-helper cell 1/T-helper cell 2 (Th1/Th2) ratio, and superoxide anion production by granulocytes (granulocyte function) were measured as immunological parameters before and after chemotherapy in 44 patients with primary ovarian cancer who received at least three consecutive courses of postoperative chemotherapy. Patients were observed during the first course of chemotherapy, and 39 patients who presented grade III or IV neutropenia were entered into this study and randomly allocated to an M-CSF-administered group (group 1; 19 patients) and a non-M-CSF-administered group (group 2; 20 patients) for the second course. For the third course, a crossover trial was conducted. In the observation period, chemotherapy significantly impaired the immunological parameters. In particular, those parameters were significantly decreased at day 14 compared to the level before chemotherapy. The values of the parameters of group 1 were significantly higher than those of group 2. In the course of chemotherapy during which M-CSF was administered, 19 of the 39 patients presented grade IV neutropenia, and received granulocyte colony-stimulating factor (G-CSF) between days 7 and 14. We compared the changes of those immunological parameters in the M-CSF alone group and the M-CSF + G-CSF group, and found that the concomitant use of G-CSF did not further improve the parameters. These results indicate that chemotherapy markedly impaired the immunological functions, and that the administration of M-CSF significantly improved the impaired immunological functions.

Macrophage colony-stimulating factor (M-CSF) prevents infectious death induced by chemotherapy in mice, while granulocyte-CSF does not

To clarify the effect of granulocyte colony-stimulating factor (G-CSF) and macrophage colony-stimulating factor (M-CSF/CSF-1) on chemotherapy-induced infection, we estimated the effect of those CSFs on a mouse model under severe myelosuppression. First, we established an animal model in which 48.9% (22/45) of C3H/Hej mice died of sepsis related to severe myelosuppression after intraperitoneal administration of a single dose (9 mg/kg) of mitomycin C (MMC). G-CSF or M-CSF was administered to this model on various administration schedules after chemotherapy, and the effect of those CSFs on survival rates, peripheral blood granulocyte counts, expression of adhesion molecules (CD11a, CD11b, CD18) on granulocytes and granulocyte function (phagocytosis and superoxide anion production) were examined. In all G-CSF administration groups, peripheral blood granulocyte counts were increased, but improvements in expression of adhesion molecules such as CD11a and CD18, and granulocyte function were less marked and survival rates were not improved. Meanwhile, when M-CSF was administered from 1 to 7 days after chemotherapy, granulocyte and platelet counts were increased, and moreover, expression of adhesion molecules and granulocyte function were markedly improved. Furthermore, the survival rate was significantly improved to 77.8% (28/36) compared with the MMC group (P < 0.05). Positive rate of blood culture examination at 7 days after chemotherapy in the M group was 0%, and was significantly lower than that in the G group (40%) and the MMC group (40%) (P < 0.05). These results demonstrated that it is important not only to increase the granulocyte counts, but also to improve granulocyte functions for preventing infection under myelosuppression after chemotherapy.