CO-EXPRESSION OF MACROPHAGE COLONY-STIMULATING FACTOR WITH ITS RECEPTOR IN HUMAN HEPATOMA CELLS AND ITS POTENTIAL ROLES

Objective: To investigate the potential role of macrophage colony-stimulating factor (M-CSF) and macrophage colony-stimulating factor receptor (M-CSF-R) on the growth of human hepatoma cells. Methods: Specimens of different origin, including tissues of human hepatocellular carcinoma (HCC), human fetal liver (FL) and normal liver (NL), the hepatoma cell lines, as well as the peripheral blood mononuclear cells (PBMC) from patients with HCC or liver metastatic tumor (LMT), were used to detect the expression levels of M-CSF and M-CSF-R by ABC immunohistochemistry staining and reverse transcription polymerase chain reaction methods the expression levels of M-CSF and M-CSF-R. Influence of monoclonal antibody against M-CSF (B5) or M-CSF-R (RE2) on proliferation ability of hepatoma cell linesin vitro was also studied. Results: The results showed that hepatoma tissues produced elevated levels of both M-CSF and M-CSF-R compared with those of fetal liver (P<0.001). The M-CSF/M-CSF-R expression levels of PBMC from hepatoma patients were higher than those of LMT patients (P<0.01,P<0.05) and the normal people (P<0.001). The hepatoma cell lines showed strong positive for M-CSF and M-CSF-R production. Both B5 and RE2 displayed a dose-dependent inhibitory effect on the growth and proliferation of hepatoma cells. Conclusion: The study indicates a co-expression model for M-CSF-R in hepatoma cells, suggesting an involvement of M-CSF/M-CSF-R in growth signaling of those malignant cells. The M-CSF/M-CSF-R seems to function through an autonomy mechanism in human hepatoma.

Granulocyte-macrophage colony-stimulating factor （GM-CSF） and T-cell responses： what we do and don＇t know

Granulocyte-macrophage colony-stimulating factor （GM-CSF） is an important hematopoietic growth factor and immune modulator. GM-CSF also has profound effects on the functional activities of various circulating leukocytes. It is produced by a variety of cell types including T cells, macrophages, endothelial cells and fibroblasts upon receiving immune stimuli. Although GM-CSF is produced locally, it can act in a paracrine fashion to recruit circulating neutrophils, monocytes and lymphocytes to enhance their functions in host defense. Recent intensive investigations are centered on the application of GM-CSF as an immune adjuvant for its ability to increase dendritic cell （DC） maturation and function as well as macrophage activity. It is used clinically to treat neutropenia in cancer patients undergoing chemotherapy, in AIDS patients during therapy, and in patients after bone marrow transplantation. Interestingly, the hematopoietic system of GM-CSF-deficient mice appears to be normal; the most significant changes are in some specific T cell responses. Although molecular cloning of GM-CSF was carried out using cDNA library oft cells and it is well known that the T cells produce GM-CSF after activation, there is a lack of systematic investigation of this cytokine in production by T cells and its effect on T cell function. In this article, we will focus mainly on the immunobiology of GM-CSF in T cells.

Neuroprotective Effect of Granulocyte Colony-stimulating Factor in a Focal Cerebral Ischemic Rat Model with Hyperlipidemia

Granulocyte colony-stimulating factor (G-CSF) has been demonstrated to have neuroprotective effects in rat model with focal cerebral ischemia through anti-apoptotic pathways and by promoting proliferation of neural stem cells. In the present study, we examined the neuroprotective effect of G-CSF in an acute focal cerebral ischemia rat model with lipid metabolism disorder. Eighty male SD rats were randomly divided into normal diet control group (NC group) and high-fat diet group (HFD group) (n = 40 in each). In HFD group, rats were fed on high fat diet to induce atherosclerosis. After 29 days, 4 rats from each group were sacrificed to evaluate the effects of different diets, and the middle cerebral artery occlusion (MCAO) was performed in the rest of the rats. MCAO rats received either G-CSF (50 μg·kg–1·mL–1) or phosphate buffered saline (PBS) injection through the external jugular vein for 5 days, which was followed by 5-bromo-deoxy uridine (BrdU, i.p., 50 mg/kg) injection for another 7 days. To evaluate the effects of G-CSF treatment on neurological function, the modified neurological severity score (mNSS) was calculated. The vascular distribution, ischemic cells proliferation, cell apoptosis and the expression of vascular endothelial growth factor (VEGF) were measured to determine the effects of G-CSF treatment. Our results showed that G-CSF-treated rats had a lower mNSS than PBS-treated rats in both NC group and HFD group. G-CSF injection promoted endothelial cell proliferation and vascular regeneration, and inhibited cell apoptosis. The serum and tissue levels of VEGF were significantly increased after G-CSF treatment. It is concluded that G-CSF exerts its neuroprotective effect in focal cerebral ischemia rats with hyperlipidemia by enhancing angiogenesis, promoting cells proliferation, decreasing cell apoptosis, and increasing local VEGF expression.

Pharmacokinetic Study of a Novel Recombinant Human Granulocyte Colony-stimulating Factor in Rats

Objective To study the pharmacokinetics of a novel recombinant human granulocyte colonystimulating factor (rhG-CSFa) in rats and to determine the proteolytic rates of rhG-CSFa in the whole blood and serum of rats in vitro. Methods The pharmacokinetics of rhG-CSFa and conventional (wild type,WT) granulocyte colonystimulating factor (G-CSF) were investigated in Sprague-Dawley rats which received either intravenous or subcutaneous injection of rhG-CSFa or WT G-CSF at three different doses (20,50,or 100 μg/kg). The blood samples of rats were collected at multiple time points (from 0.08 to 12 h) and the concentrations of rhG-CSFa and WT G-CSF in serum were determined with a sandwich enzyme-linked immunosorbent assay (ELISA). For the study of proteolytic rates in vitro,the concentrations of rhG-CSFa or WT G-CSF were determined at 3-minute intervals after addition of the respective drug to rat’s whole blood or serum. Results Pharmacokinetic analysis of serum rhG-CSFa or WT G-CSF levels indicated that,at each dose tested,for either route of drug administration,the area under concentration-time curve values and the maximum serum concentration of rhG-CSFa were higher than those of WT G-CSF,and the serum half life of rhG-CSFa was longer than that of WT G-CSF. Subsequent in vitro whole blood and serum stability study showed that the rates of drug degradation in WT G-CSF were 1.8 folds and 1.5 folds higher than those in rhG-CSFa,respectively. Conclusion rhG-CSFa has better serum and whole blood stability in vitro and higher bioavailability in vivo as compared to WT G-CSF.

Mobilization of Peripheral Blood Stem Cells Using Regimen Combining Docetaxel with Granulocyte Colony-stimulating Factor in Breast Cancer Patients

Objective：To evaluate the effectiveness and safety of the mobilization of peripheral blood hematopoietic stem cells by combining docetaxel with granulocyte colony-stimulating factor（G-CSF） in breast cancer patients.Methods：A total of 57 breast cancer patients were treated with docetaxel 120 mg/m2.When the white blood cell（WBC） count decreased to 1.0×109/L,patients were given G-CSF 5-g/kg daily by subcutaneous injection until the end of apheresis.Peripheral blood mononuclear cells（MNC） were isolated by Cobe Spectra Apheresis System.The percentage of CD34＋ cell was assayed by flow cytometry.Results：At a median 6 of days（range 3-8） after the administration of docetaxel,the median WBC count decreased to 1.08×109/L（range 0.20-2.31）.The median duration of G-CSF mobilization was 3 days（range 2-7）.The MNC collection was conducted 8-12 days（median 10 days） after docetaxel treatment.The median MNC was 5.35×108/kg（range 0.59-14.07）,the median CD34＋ cell count was 2.43×106/kg（range 0.16-16.69）.The CD34＋ cell count was higher than 1.00×106/kg in 47 of 57 cases（82.46%） and higher than 2.00×106/kg in 36 cases（63.16%）.The CD34＋ cell count was higher than 2.00×106/kg in 27 collections（23.68%）.The MNC count and the CD34＋ cell count were correlated with the bottom of WBC after docetaxel chemotherapy（r=0.364,0.502,P=0.005,0.000）.The CD34＋ cell count was correlated with the MNC count（r=0.597,P=0.000）.The mobilization and apheresis were well tolerated in all patients.Mild perioral numbness and numbness of hand or feet were observed in 3 cases.No serious adverse events were reported.Conclusion：Mobilization of peripheral blood hematopoietic stem cell by combining docetaxel with G-CSF was effective and safety in breast cancer patients.

Granulocyte-macrophage colony-stimulating factor protects mice against hepatocellular carcinoma by ameliorating intestinal dysbiosis and attenuating inflammation

BACKGROUND Hepatocellular carcinoma(HCC)is the third leading cause of cancer mortality worldwide.The gut microbiota can help maintain healthy metabolism and immunity.Granulocyte-macrophage colony-stimulating factor(GM-CSF)is a critical factor in promoting health and homeostasis;it promotes intestinal immunity,stimulates bone marrow precursors to generate macrophage colonies,and enhances the antibacterial and antitumor activity of circulating monocytes.As such,GM-CSF may protect against HCC development by regulating immunity as well as intestinal microecology.AIM To investigate the impact of GM-CSF on the gut microbiome and metabolic characteristics of HCC.METHODS Thirty-six male BALB/c nude mice were divided into three groups:Control(n=10),HCC(n=13),and HCC+GM-CSF(GM-CSF overexpression,n=13).We utilized HCC cells to establish orthotopic transplantation tumor models of HCC with normal and over-expressing GM-CSF.Liver injury,immune inflammatory function and intestinal barrier function were evaluated.The fecal microbiome and metabolome were studied using 16S rRNA absolute quantification sequencing and gas chromatography-mass spectrometry.RESULTS GM-CSF overexpression significantly affected the gut microbiome of mice with HCC and resulted in a high abundance of organisms of the genera Roseburia,Blautia and Butyricimonass,along with a significant reduction in Prevotella,Parabacteroides,Anaerotruncus,Streptococcus,Clostridium,and Mucispirillum.Likewise,GM-CSF overexpression resulted in a substantial increase in fecal biotin and oleic acid levels,along with a prominent decrease in the fecal succinic acid,adenosine,fumaric acid,lipoic acid,and maleic acid levels.Correlation analysis revealed that the intestinal microbiota and fecal metabolites induced by GM-CSF were primarily involved in pathways related to reducing the inflammatory response,biotin metabolism,and intestinal barrier dysfunction.CONCLUSION GM-CSF can protect against HCC development by regulating immunity and modulating the abundance of specific intestinal microorganisms and their metabolites.This study provides new insights into the therapeutic approaches for HCC.

Granulocyte-macrophage colony-stimulating factor-transfected bone marrow stromal cells for the treatment of ischemic stroke

Adult, male, Sprague-Dawley rats were injected with granulocyte-macrophage colony-stimulating factor-transfected bone marrow stromal cells （GM-CSF-BMSCs） into the ischemic boundary zone at 24 hours after onset of middle cerebral artery occlusion. Results showed reduced infarct volume, decreased number of apoptotic cells, improved neurological functions, increased angiogenic factor expression, and increased vascular density in the ischemic boundary zone in rats that underwent GM-CSF-BMSCs transplantation compared with the BMSCs group. Experimental findings suggested that GM-CSF-BMSCs could serve as a potential therapeutic strategy for ischemic stroke and are superior to BMSCs alone.

CONSTRUCTION OF EUKARYOTIC EXPRESSION VECTOR WITH GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR GENE

Objective: To construct the eukaryotic expression vector that express human granulocyte-macrophage colony-stimulating factor (hGM-CSF) gene for making highly express in mammalian cells. Methods: Extract totally RNA from the induced human fetal lung (HFL) cell line. HGM-CSF cDNA was obtained by reverse transcription-polymerase chain reaction (RT-PCR), and then directionally subcloned into the HindIII and EcoRI site on the pcDNA3.1 plasmid, which was controlled by the CMV promoter, to form the recombinant expressing vector pcDNA3.1-GM-CSF. Results: The PCR amplification was identified and the sequence was analyzed, the results showed that hGM-CSF was properly inserted into the vector and the sequence was correct.

DETERMINATION OF SERUM SOLUBLE MACROPHAGE COLONY-STIMULATING FACTOR RECEPTOR LEVELS IN PATIENTS WITH HEMATOLOGICAL DISEASES

Objective: To investigate the serum levels of soluble macrophage colony-stimulating factor receptor (M-CSFsR) in normal subjects and patients with hematological diseases and its clinical implications in hematological diseases. Methods: The concentration of M-CSFsR was determined by ELISA. The serum M-CSFsR was identified and characterized by immunoprecipitation and Western blotting. Results: The mean serum level of M-CSFsR of 123 normal individuals was 0.48 ng/ml ± 0.41 ng/ml. Immunoprecipitation and Western blotting assay revealed a ～ 90kD band of serum M-CSFsR. The mean serum M-CSFsR level of 60 patients with acute lymphoblastic leukemia (ALL), 36 patients with acute myeloblastic leukemia (AML), 13 patients with myelodysplastic syndrome (MDS) and 42 patients with aplastic anemia (AA) .were 0.22 ng/ml±0.23 ng/ml, 0.17 ng/ml±0.16 ng/ml, 0.19 ng/ml±0.16 ng/ml and 0.23 ng/ml±0.21 ng/ml, respectively, which were significantly lower than that of normal subjects (P=0.002 ,P<0.0001,P<0.0001 andP<0.0001). The mean serum M-CSFsR level of 51 idiopathic thrombocytopenic purpura (ITP) patients was significantly higher than that of normal subjects (2.05 ng/ml±2.75 ng/ml,P<0.0001). Conclusion: The serum M-CSFsR levels of patients with ALL, AML, MDS and AA were significantly lower, while the level of patients with ITP was significantly higher than that of normal individuals. Patients with severe ITP (platelet count<30×l09/L) had the highest M-CSFsR level. It suggested that the abnormal levels of serum M-CSFsR may associate with some hematological diseases and may contribute to the pathological process.

Granulocyte colony-stimulating factor increases extracellular glutamic acid uptake and suppresses free radicals in an experimental model of amyotrophic lateral sclerosis

Excitatory amino acid toxicity and free radical damage play important roles in amyotrophic lateral sclerosis. Granulocyte colony-stimulating factor （G-CSF） protects nerve cells exposed to high-concentrations of glutamic acid, suggesting positive effects in the treatment of amyotrophic lateral sclerosis. The present study induced in vitro motor neuron injury using glutamic acid excitotoxicity, and the biochemical effects of G-CSF on glutamic acid concentration were determined. In addition, the effects of G-CSF on superoxide dismutase, glutathione peroxidase activity in motor neurons, and malondialdehyde and nitric oxide contents were analyzed. Immunohistochemistry was performed to measure neuronal survival. Results revealed that G-CSF significantly suppressed free radical activity, inhibited excitotoxicity, and reduced apoptosis and loss of motor neurons in the anterior horn of the spinal cord.

Changes of Circulating Platelet-Derived Growth Factor and Granulocyte Colony-Stimulating Factor in Patients with Condyloma Acuminatum

Objective: To study the expression levels of platelet-derived growth factor (PDGF) and granulocyte colony-stimulatingfactor (G-CSF) in peripheral blood and their role in thepathogenesis of Condyloma acuminatum (CA). Methods: Sera were taken from 70 patients with Condylomaacuminatum and compared with 35 healthy controls. PDGFand G-CSF in serum were quantitated using a dual antibodysandwich enzyme-linked immunoabsorbent assay (ELISA). Results: Serum concentrations of PDGF and G-CSF weresignificantly increased in patients with Condylomaacuminatum (CA) compared to controls (P<0.001 and P<0.005respectively). Serum levels of PDGF and G-CSF correlatedwith clinical severity of CA, but no significant difference wasobserved between different duration of disease groups. Asignificant positive correlation was noticed between neutrophilcount and G-CSF levels (γ=0.38, P<0.001), and the neutrophilcount showed no significant correlation with PDGE Conclusion: The results indicated that increased expressionof PDGF an -CSF in peripheral blood might be involved in pathogenesis of CA.

Granulocyte colony-stimulating factor promotes growth of processes,growth associated protein 43 and microtubule-associated protein 2 expression in cultured rat retinal ganglion cells in vitro

Following granulocyte colony-stimulating factor （G-CSF） treatment,the growth of processes in cul-tured rat retinal ganglion cells （RGCs） in vitro,expression of growth associated protein 43,and expression of microtubule-associated protein 2 mRNA expression were significantly increased.In contrast,RhoA/Rock protein content was significantly reduced by G-CSF treatment.These results indicate that G-CSF promotes the growth of processes in RGCs and increases the expression of growth-associated protein 43 and microtubule-associated protein 2 mRNA by inhibiting the RhoA/Rock pathway,thereby benefiting axonal repair in RGCs exposed to hypoxia.

Refolding with Simultaneous Purification of Recombinant Human Granulocyte Colony-stimulating Factor from Escherichia coli Using Strong Anion Exchange Chromatography

The urea denatured recombinant human granulocyte colony-stimulating factor (rhG- CSF) which was expressed in Escheriachia coli (E. coli) was refolded with simultaneous purification by strong anion exchange chromatography (SAX) in the presence of low concentration- of urea. The effect of urea concentration on this refolding process was investigated. The obtained refolded rhG-CSF has a high specific activity of 2.3×108 U/mg, demonstrating that the proteins were completely refolded during the chromatographic process. With only one step by SAX in 40 min, purity and mass recovery of the refolded and purified rhG-CSF were 97% and 43%, respectively.

Anti-apoptotic effects of recombinant human granulocyte colony-stimulating factor in focal cerebral ischemic rats

The neuroprotective effects of granulocyte colony-stimulating factor in cerebral ischemia/reperfusion injury are currently contentious. The present study examined the effects of subcutaneous injection of recombinant human granulocyte colony-stimulating factor （50 pg/kg） over 5 days in a model of cerebral ischemia/reperfusion with intraluminal filament occlusion in rats. The results indicated that recombinant human granulocyte colony-stimulating factor reduced brain infarct volume following cerebral ischemia/reperfusion injury in rats, down-regulated the expression of caspase-3 mRNA （a key protease for apoptosis in the cerebral ischemia zone）, lowered the rate of neuronal apoptosis in the cerebral ischemia zone, and notably ameliorated neurological function. These results indicate that recombinant human granulocyte colony-stimulating factor has anti-apoptotic effects on neurons following focal cerebral ischemia/reperfusion injury, and exerts neuroprotective effects.

Chronic Toxicity of a Novel Recombinant Human Granulocyte Colony-stimulating Factor in Rats

Objective To assess the severity and reversibility of the chronic toxicity of a novel recombinant human granulocyte colony-stimulating factor (rhG-CSFa) in rats and the dose-effect relationship.Methods A total of 100 Sprague-Dawley rats (equal numbers of male and female) were randomly divided into five groups (20 rats in each group):four groups were treated with rhG-CSFa at 500,100,10,1 μg/kg,respectively,and one group was treated with vehicle only to serve as the control.The rats were received subcutaneous injections of rhG-CSFa or vehicle daily for 13 weeks.During the course of the chronic toxicity study,the physical status,body weight,and food consumption were monitored.Half of the rats in each group (n=10) were sacrificed after the last rhG-CSFa administration,and the other half were sacrificed at five weeks after the last rhG-CSFa administration.Urinalyses,blood biochemistry,hematological analysis,histopathological examination,and immunological tests were performed for each of the rats.Results The hematological analyses revealed that the mean white blood cells count,neutrophils count,and neutrophils percentage were increased in male rats at the dose of 10 μg/kg or higher,and these were related with the biological activity of rhG-CSFa.Some small abnormalities were observed in the spleen of a few rats when used highest dose (500 μg/kg,a dosage of 200 folds higher than the normal clinical dosage),but these abnormalities were recovered within 5-week recovery period.No other rhG-CSFa-related abnormalities were observed in this chronic toxicity study.Conclusion No significant toxicity and immunogenicity are observed with rhG-CSFa administration to rats in the chronic toxicity studies.

Mobilization Efficiency of Granulocyte Colony-stimulating Factor and Stem Cell Factor to Bone Marrow Mononuclear Cells and Mechanisms

The mobilization efficiency of granulocyte colony-stimulating factor (G-CSF) and stem cell factor (SCF) to bone marrow mononuclear cells (MNCs) in mice was observed, and the changes of CXCL12/CXCR4 signal were detected in order to find out the mobilization mechanism of stem cells. Kunming mice were randomly divided into two groups. The mice in treatment group were subjected to subcutaneous injection of G-CSF at a dose of 100 μg/kg and SCF at a dose of 25 μg/kg every day for 5 days, and those in control group were given isodose physiological saline. The MNCs were separated, counted and cultured, and the colony-forming unit-fibroblast (CFU-F) was evaluated. CD34+CXCR4+ MNCs were sorted by flow cytometry. The expression of CXCL12 protein in bone marrow extracellular fluid was detected by ELISA, and that of CXCL12 mRNA in bone marrow was measured by RT-PCR. The results showed that the counts of MNCs in peripheral blood and bone marrow were increased after administration of G-CSF/SCF (P<0.01). The factors had a dramatic effect on the expansion capability of CFU-F (P<0.05). Flow cytometric of bone marrow MNCs surface markers revealed that CD34+CXCR4+ cells accounted for 44.6%±8.7% of the total CD34+ MNCs. Moreover, G-CSF/SCF treatment induced a decrease in bone marrow CXCL12 mRNA that closely mirrored the fall in CXCL12 protein. In this study, it is evidenced that G-CSF/SCF can effectively induce MNCs mobilization by disrupting the balance of CXCL12/CXCR4 signaling pathway in the bone marrow and down-regulating the interaction of CXCL12/CXCR4.

Disseminated carcinomatosis of the bone marrow caused by granulocyte colony-stimulating factor:A case report and review of literature

BACKGROUND Disseminated carcinomatosis of the bone marrow(DCBM)is a widespread metastasis with a hematologic disorder that is mainly caused by gastric cancer.Although it commonly occurs as a manifestation of recurrence long after curative treatment,the precise mechanism of relapse from dormant status remains unclear.Granulocyte colony-stimulating factor(G-CSF)can promote cancer progression and invasion in various cancers.However,the potential of G-CSF to trigger recurrence from a cured malignancy has not been reported.CASE SUMMARY A 55-year-old Japanese woman was diagnosed with Ewing sarcoma localized on the fifth lumbar vertebrae 6 years after curative gastrectomy for T1 gastric cancer.After palliative surgery to release nerve compression,pathological diagnosis of the resected specimen was followed by curative radiation and chemotherapy.During treatment,G-CSF was administered 32 times for severe neutropenia prophylaxis.Eight months after completing definitive treatment,she complained of severe back pain and was diagnosed as multiple bone metastases with DCBM from gastric cancer.Despite palliative chemotherapy,she died of disseminated intravascular coagulation 13 d after the diagnosis.Immunohistochemical examination of the autopsied bone marrow confirmed a diffuse positive staining for the G-CSF receptor(G-CSFR)in the relapsed gastric cancer cell cytoplasm,whereas the primary lesion cancer cells showed negative staining for G-CSFR.In this case,G-CSF administration may have been the key trigger for the disseminated relapse of a dormant gastric cancer.CONCLUSIONWhen administering G-CSF to cancer survivors,recurrence of a preceding cancer should be monitored even after curative treatment.

A New Protocol for Solubilization, Refolding and Purification of Recombinant Human Granulocyte Colony-stimulating Factor in Inclusion Bodies

Recombinant human granulocyte colony-stimulating factor （rhG-CSF） in inclusion bodies was solubilized by 8 mol/L urea solution and subsequently precipitated by acetone to improve its purity. After that, the precipitates were solubilized by sodium hydroxide solution containing 2 mol/L urea. Then the solubilized rhG-CSF was passed through a size exclusion chromatography for refolding and extensive purification, and further purified by a weak anion exchange chromatography. The purity and mass recovery of refolded rhG-CSF were 96.5% and 75.6%, respectively. The bioactivity was 8.4x10^7 IU/mg.

Selective deletion of the soluble Colony-Stimulating Factor 1 isoform in vivo prevents estrogen-deficiency bone loss in mice

Neutralizing CSF1 in vivo completely prevents ovariectomy （OVX）-induced bone loss in mice. There are two isoforms of CSF1, soluble （sCSF1）, and membrane-bound （mCSF1）, but their individual biological functions are unclear. It had been previously reported that mCSF1 knockout （K/O） and wild type （Wt） female mice experience the same degree of bone loss following OVX. In Wt mice the expression of sCSF1 was elevated fourfold in skeletal tissue following OVX while expression of mCSF1 was unchanged. To examine the role of sCSF1 in OVX-induced bone loss, mice were engineered in which sCSF1 was not expressed but expression of mCSF1 was unaffected （sCSF1 K/O）. Isoform-specific reverse transcription PCR confirmed the absence of transcripts for sCSF1 in bone tissue isolated from these animals and no circulating CSF1 was detected by ELISA. Surprisingly, there were no significant differences in bone mineral density （BMD） between sCSF1 K/O mice and Wt controls as assessed by dual-energy X-ray absorptiometry and micro-CT. However, one month after OVX, femoral, spinal and total BMD had declined by 11.2%, 8.9%, and 8.7% respectively in OVX-Wt animals as compared to Sham-OVX. In contrast OVX sCSF1 K/O mice showed changes of ＋0.1%, - 2.4%, and ＋2.3% at the same 3 sites compared to Sham-OVX sCSF1 K/O mice. These data indicate important non-redundant functions for the two isoforms of CSF1 and suggest that sCSF1, but not mCSF1, plays a key role in estrogen-deficiency bone loss.

Antiviral Activity of Silkworm Expressed Recombinant Human Macrophage Colony-Stimulating Factor in Vitro and Its Mechanism

Cells, pretreated with the recombinant human macrophage colony-stimulating factor (rhM-CSF) expressed in silkworm larvae, were inoculated with several viruses to observe the effect of rhM-CSF on viral replication. The results showed that in cultures of fibroblast derived from human fetal skin-muslce tissues infected with the viruses (including VSV, rhinovirus, influenza virus type A3, HSV-1, HSV-2, adenovirus type 6 and type 11), rhM-CSF inhibited the virus-induced cytopathy, which defered or relieved the cytophathy and that in the cells derived from breast feeding rabbit kidney infected with HSV-1, rhM-CSF reduced titer of the virus in a rhM-CSF dose-dependent pattern,in which rhM-CSF with the dose of 1×106 U/L made the viral titer drop dwon over 200 times. This antiviral activity of rhM-CSF could be partially neutralized by anti-IFN-βMcAb, but not by antiTNF-α, anti-IFN-α, or anti-IFA-γ McAb, indicating the mechanism of the antiviral activity of MCSF is related to the induction of IFN-β.