Opposite effects of different doses of MCSF on ERK phosphorylation and cell proliferation in macrophages

Profiling the human immune response to Mycobacterium tuberculosis by human cytokine array

OBJECT

Tuberculosis (TB) continues to be one of the most serious infectious diseases in the world, however, no effective biomarkers can be used for rapid screening of latent tuberculosis infection (LTBI) and active TB. In this study, serum cytokines were screened and tested as potential biomarker for TB diagnosis.

METHOD

Cytokine array was used to track the cytokine profile and its dynamic change after TB infection. The different expressions of cytokines were confirmed by ELISA assay. ROC curve analyses were used to evaluate the efficacy of a cytokine or cytokine combination for diagnosis.

RESULTS

Eotaxin-2, ICAM-1, MCSF, IL-12p70, and IL-11 were significantly higher in the LTBI individuals. I-309, MIG, Eotaxin-2, IL-8, ICAM-1, IL-6sR, and Eotaxin were significantly higher in active TB patients. ROC curve analyses gave AUCs of 0.843, 0.898, and 0.888 for I-309, MIG, and IL-8, respectively, and 0.894 for the combination panel in active TB diagnosis. IFN-γ/IL-4 and IL-2/TNF-α ratios exhibit dynamic changes in the healthy control and LTBI to different stages of active TB.

CONCLUSIONS

Serum cytokines, including I-309 and MIG, IL-8, Extoxin-2, ICAM-1 and combinations of cytokines, including IFN-γ/IL-4 and IL-2/TNF-α, can be used as serum biomarkers for LTBI and active TB screening, thus indicating prospective clinical applications.

CSF-1 receptor signaling in myeloid cells

The CSF-1 receptor (CSF-1R) is activated by the homodimeric growth factors colony-stimulating factor-1 (CSF-1) and interleukin-34 (IL-34). It plays important roles in development and in innate immunity by regulating the development of most tissue macrophages and osteoclasts, of Langerhans cells of the skin, of Paneth cells of the small intestine, and of brain microglia. It also regulates the differentiation of neural progenitor cells and controls functions of oocytes and trophoblastic cells in the female reproductive tract. Owing to this broad tissue expression pattern, it plays a central role in neoplastic, inflammatory, and neurological diseases. In this review we summarize the evolution, structure, and regulation of expression of the CSF-1R gene. We discuss the structures of CSF-1, IL-34, and the CSF-1R and the mechanism of ligand binding to and activation of the receptor. We further describe the pathways regulating macrophage survival, proliferation, differentiation, and chemotaxis downstream from the CSF-1R.

Chromatin-associated CSF-1R binds to the promoter of proliferation-related genes in breast cancer cells

The colony-stimulating factor-1 (CSF-1) and its receptor CSF-1R physiologically regulate the monocyte/macrophage system, trophoblast implantation and breast development. An abnormal CSF-1R expression has been documented in several human epithelial tumors, including breast carcinomas. We recently demonstrated that CSF-1/CSF-1R signaling drives proliferation of breast cancer cells via ‘classical' receptor tyrosine kinase signaling, including activation of the extracellular signal-regulated kinase 1/2. In this paper, we show that CSF-1R can also localize within the nucleus of breast cancer cells, either cell lines or tissue specimens, irrespectively of their intrinsic molecular subtype. We found that the majority of nuclear CSF-1R is located in the chromatin-bound subcellular compartment. Chromatin immunoprecipitation revealed that CSF-1R, once in the nucleus, binds to the promoters of the proliferation-related genes CCND1, c-JUN and c-MYC. CSF-1R also binds the promoter of its ligand CSF-1 and positively regulates CSF-1 expression. The existence of such a receptor/ligand regulatory loop is a novel aspect of CSF-1R signaling. Moreover, our results provided the first evidence of a novel localization site of CSF-1R in breast cancer cells, suggesting that CSF-1R could act as a transcriptional regulator on proliferation-related genes.

Tyrosine kinase inhibitors ameliorate autoimmune encephalomyelitis in a mouse model of multiple sclerosis

Multiple sclerosis is an autoimmune disease of the central nervous system characterized by neuroinflammation and demyelination. Although considered a T cell-mediated disease, multiple sclerosis involves the activation of both adaptive and innate immune cells, as well as resident cells of the central nervous system, which synergize in inducing inflammation and thereby demyelination. Differentiation, survival, and inflammatory functions of innate immune cells and of astrocytes of the central nervous system are regulated by tyrosine kinases. Here, we show that imatinib, sorafenib, and GW2580-small molecule tyrosine kinase inhibitors-can each prevent the development of disease and treat established disease in a mouse model of multiple sclerosis. In vitro, imatinib and sorafenib inhibited astrocyte proliferation mediated by the tyrosine kinase platelet-derived growth factor receptor (PDGFR), whereas GW2580 and sorafenib inhibited macrophage tumor necrosis factor (TNF) production mediated by the tyrosine kinases c-Fms and PDGFR, respectively. In vivo, amelioration of disease by GW2580 was associated with a reduction in the proportion of macrophages and T cells in the CNS infiltrate, as well as a reduction in the levels of circulating TNF. Our findings suggest that GW2580 and the FDA-approved drugs imatinib and sorafenib have potential as novel therapeutics for the treatment of autoimmune demyelinating disease.

Pombe Cdc15 homology (PCH) proteins: coordinators of membrane-cytoskeletal interactions

Cellular adhesion, motility, endocytosis, exocytosis and cytokinesis involve the coordinated reorganization of the cytoskeleton and of the plasma membrane. The 'Pombe Cdc15 homology' (PCH) family of adaptor proteins has recently been shown to coordinate the membrane and cytoskeletal dynamics involved in these processes by curving membranes, recruiting dynamin and controlling the architecture of the actin cytoskeleton. Mutations in PCH family members or proteins that interact with them are associated with autoinflammatory, neurological or neoplastic diseases. Here, we review the nature, actions and disease associations of the vertebrate PCH family members, highlighting their fundamental roles in the regulation of processes involving membrane-cytoskeletal interactions.

Macrophage colony-stimulating factor receptor induces tyrosine phosphorylation of SKAP55R adaptor and its association with actin

The production, survival, and function of monocytes and macrophages are regulated by the macrophage colony-stimulating factor (M-CSF or CSF-1) through its tyrosine kinase receptor. M-CSF receptor activates multiple cytoplasmic pathways in which adaptor and scaffolding proteins play a central role. In this study, we showed that SKAP55-related (SKAP55R) adaptor protein is expressed in myeloid cells and macrophages and is rapidly and transiently tyrosine-phosphorylated in response to M-CSF. M-CSF induced SKAP55R association with other tyrosine-phosphorylated proteins and with actin. When overexpressed in myeloid cells, SKAP55R decreased M-CSF-dependent proliferation without affecting differentiation. Altogether, these results demonstrate that SKAP55R adaptor is implicated in the M-CSF signaling pathway and suggest its role as a negative regulator of growth. Moreover, specific association between SKAP55R and actin support the idea that SKAP55R is implicated in the regulation of actin dynamics under the control of M-CSF.

TACE/ADAM-17 maturation and activation of sheddase activity require proprotein convertase activity

Proprotein convertases (PCs) have been proposed to play a role in tumor necrosis factor-alpha converting enzyme (TACE) processing/activation. Using the furin-deficient LoVo cells, as well as the furin-proficient synoviocytes and HT1080 cells expressing the furin inhibitor alpha(1)-PDX, we demonstrate that furin activity alone is not sufficient for effective maturation and activation of the TACE enzyme. Data from in vitro and in vivo cleavage assays indicate that PACE-4, PC5/PC6, PC1 and PC2 can directly cleave the TACE protein and/or peptide. PC inhibition in macrophages reduced the release of soluble TNF-alpha from transmembrane pro-TNF-alpha. We therefore conclude that furin, in addition to other candidate PCs, is involved in TACE maturation and activation.

The influence of very low doses of Cisplatin on tumor cell proliferation in vitro and on some hematological and enzymatic parameters of healthy rats

Healthy rats had been treated for 2 or 6 weeks with 1.0 mL of 10(-8) and 10(-16) mg/mL of cisplatin. After 2 weeks of treatment, a significant increase in leukocyte and erythrocyte count and also in hematocrit was observed. Among leukocytes the number of neutrophils and eosinophils significantly increased. Biochemical analyses indicated a decrease in the glycogen content in the liver and kidneys after 2 weeks of treatment with low doses of cisplatin but at the end of the experiment (8th week of experiment) the stores of glycogen increased significantly. Biochemical analyses concerning the activity of some enzymes in the liver revealed a significant increase of peroxidase and acid phosphatase as well as catalase activities after 2 weeks of treatment. However, catalase was induced by a very low concentration of cisplatin, 10(-16) mg/mL. After the cessation of cisplatin treatment the activity of enzymes returned to normal values.Human lung carcinoma cell line A(549) (ECACC No 86012804) was also studied after treatment with the same doses of cisplatin and inhibition of its growth was observed. The results of these experiments strongly indicated that low doses of cisplatin could be stimulating for healthy cells but cytostatic for tumor cells.Possible mechanisms involved in the biological activity of very low cisplatin concentrations are discussed.