Src family kinase expression and subcellular localization in macrophages: implications for their role in CSF-1-induced macrophage migration.

A major role of colony-stimulating factor-1 is to stimulate the differentiation of mononuclear phagocytic lineage cells into adherent, motile, mature macrophages. The colony-stimulating factor-1 receptor transduces colony-stimulating factor-1 signaling, and we have shown previously that phosphatidylinositol 3-kinase p110δ is a critical mediator of colony-stimulating factor-1-stimulated motility through the colony-stimulating factor-1 receptor pY721 motif. Src family kinases are also implicated in the regulation of macrophage motility and in colony-stimulating factor-1 receptor signaling, although functional redundancy of the multiple SFKs expressed in macrophages makes it challenging to delineate their specific functions. We report a comprehensive analysis of individual Src family kinase expression in macrophage cell lines and primary macrophages and demonstrate colony-stimulating factor-1-induced changes in Src family kinase subcellular localization, which provides clues to their distinct and redundant functions in macrophages. Moreover, expression of individual Src family kinases is both species specific and dependent on colony-stimulating factor-1-induced macrophage differentiation. Hck associated with the activated colony-stimulating factor-1 receptor, whereas Lyn associated with the receptor in a constitutive manner. Consistent with this, inhibitor studies revealed that Src family kinases were important for both colony-stimulating factor-1 receptor activation and colony-stimulating factor-1-induced macrophage spreading, motility, and invasion. Distinct colony-stimulating factor-1-induced changes in the subcellular localization of individual SFKs suggest specific roles for these Src family kinases in the macrophage response to colony-stimulating factor-1.

Dwyer AR ，Mouchemore KA ，Steer JH ，Sunderland AJ ，Sampaio NG ，Greenland EL ，Joyce DA ，Pixley FJ ... -  《-》

Prostaglandin E2 transactivates the colony-stimulating factor-1 receptor and synergizes with colony-stimulating factor-1 in the induction of macrophage migration via the mitogen-activated protein kinase ERK1/2.

Prostaglandin E2 (PGE2), a key mediator of immunity, inflammation, and cancer, acts through 4 G-protein-coupled E-prostanoid receptors (EPs 1-4). Crosstalk between EPs and receptor tyrosine kinases also occurs. Colony-stimulating factor-1 receptor (CSF-1R) is an RTK that sustains the survival, proliferation, and motility of monocytes/macrophages, which are an essential component of innate immunity and cancer development. The aim of this study was to investigate on a possible crosstalk between EP and CSF-1R. In BAC1.2F5 and RAW264.7 murine macrophages, CSF-1 (EC₅₀ = 18.1 and 10.2 ng/ml, respectively) and PGE2 (EC₅₀ = 1.5 and 5.5 nM, respectively) promoted migration. PGE2 induced rapid CSF-1R phosphorylation that was dependent on Src family kinases (SFKs). CSF-1R inhibition reduced PGE2-elicited ERK1/2 phosphorylation and macrophage migration, indicating that CSF-1R plays a role in PGE2-mediated immunoregulation. EP4 appeared responsible for functional PGE2/CSF-1R crosstalk. Furthermore, PGE2 synergized with CSF-1 in inducing ERK1/2 phosphorylation and macrophage migration. ERK1/2 inhibition completely blocked migration induced by the combination CSF-1/PGE2. CSF-1/PGE2 functional interaction with respect to migration also occurred in bone marrow-derived murine macrophages (EC₅₀ CSF-1, 6.7 ng/ml; EC₅₀ PGE2, 16.7 nM). These results indicated that PGE2 transactivates CSF-1R and synergizes with its signaling at ERK1/2 level in promoting macrophage migration.

Digiacomo G ，Ziche M ，Dello Sbarba P ，Donnini S ，Rovida E ... -  《-》

Fibronectin induces macrophage migration through a SFK-FAK/CSF-1R pathway.

Digiacomo G ，Tusa I ，Bacci M ，Cipolleschi MG ，Dello Sbarba P ，Rovida E ... -  《-》

Colony-stimulating factor-1 receptor utilizes multiple signaling pathways to induce cyclin D2 expression.

:Colony-stimulating factor-1 (CSF-1) induces expression of immediate early gene, such as c-myc and c-fos and delayed early genes such as D-type cyclins (D1 and D2), whose products play essential roles in the G1 to S phase transition of the cell cycle. Little is known, however, about the cytoplasmic signal transduction pathways that connect the surface CSF-1 receptor to these genes in the nucleus. We have investigated the signaling mechanism of CSF-1-induced D2 expression. Analyses of CSF-1 receptor autophosphorylation mutants show that, although certain individual mutation has a partial inhibitory effect, only multiple combined mutations completely block induction of D2 in response to CSF-1. We report that at least three parallel pathways, the Src pathway, the MAPK/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway, and the c-myc pathway, are involved. Induction of D2 is partially inhibited in Src(-/-) bone marrow-derived macrophages and by Src inhibitor PP1 and is enhanced in v-Src-overexpressing cells. Activation of myc's transactivating activity selectively induces D2 but not D1. Blockade of c-myc expression partially blocks CSF-1-induced D2 expression. Complete inhibition of the MEK/ERK pathway causes 50% decrease of D2 expression. Finally, simultaneous inhibition of Src, MEK activation, and c-myc expression additively blocks CSF-1-induced D2 expression. This study indicates that multiple signaling pathways are involved in full induction of a single gene, and this finding may also apply broadly to other growth factor-inducible genes.

Dey A ，She H ，Kim L ，Boruch A ，Guris DL ，Carlberg K ，Sebti SM ，Woodley DT ，Imamoto A ，Li W ... -  《MOLECULAR BIOLOGY OF THE CELL》

Src-family kinases play an essential role in differentiation signaling downstream of macrophage colony-stimulating factor receptors mediating persistent phosphorylation of phospholipase C-gamma2 and MAP kinases ERK1 and ERK2.

Bourgin-Hierle C ，Gobert-Gosse S ，Thérier J ，Grasset MF ，Mouchiroud G ... -  《-》