Dataset Information

Molecular Analysis of a Short-term Model of ?-Glucans-Trained Immunity Highlights the Accessory Contribution of GM-CSF in Priming Mouse Macrophages Response.

ABSTRACT: ?-Glucans (BGs) are glucose polymers present in the fungal cell wall (CW) and, as such, are recognized by innate immune cells as microbial-associated pattern through Dectin-1 receptor. Recent studies have highlighted the ability of the pathogenic yeast Candida albicans or its CW-derived ?(1,3) (1,6)-glucans to increase human monocytes cytokine secretion upon secondary stimulation, a phenomenon now referred as immune training. This ability of monocytes programming confers BGs an undeniable immunotherapeutic potential. Our objective was to determine whether BGs from Saccharomyces cerevisiae, a non-pathogenic yeast, are endowed with such a property. For this purpose, we have developed a short-term training model based on lipopolysaccharide re-stimulation of mouse bone marrow-derived macrophages primed with S. cerevisiae BGs. Through a transcriptome analysis, we demonstrated that BGs induced a specific gene expression signature involving the PI3K/AKT signaling pathway as in human monocytes. Moreover, we showed that over-expression of Csf2 (that encodes for GM-CSF) was a Dectin-1-dependent feature of BG-induced priming of macrophages. Further experiments confirmed that GM-CSF up-regulated Dectin-1 cell surface expression and amplified macrophages response along BG-mediated training. However, the blockade of GM-CSFR demonstrated that GM-CSF was not primarily required for BG-induced training of macrophages although it can substantially improve it. In addition, we found that mouse macrophages trained with BGs upregulated their expression of the four and a half LIM-only protein 2 (Fhl2) in a Dectin-1-dependent manner. Consistently, we observed that intracellular levels of FHL2 increased after stimulation of macrophages with BGs. In conclusion, our experiments provide new insights on GM-CSF contribution to the training of cells from the monocytic lineage and highlights FHL2 as a possible regulator of BG-associated signaling.

SUBMITTER: Walachowski S

PROVIDER: S-EPMC5601002 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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Molecular Analysis of a Short-term Model of β-Glucans-Trained Immunity Highlights the Accessory Contribution of GM-CSF in Priming Mouse Macrophages Response.

Walachowski Sarah S Tabouret Guillaume G Fabre Marion M Foucras Gilles G

Frontiers in immunology 20170911

β-Glucans (BGs) are glucose polymers present in the fungal cell wall (CW) and, as such, are recognized by innate immune cells as microbial-associated pattern through Dectin-1 receptor. Recent studies have highlighted the ability of the pathogenic yeast <i>Candida albicans</i> or its CW-derived β(1,3) (1,6)-glucans to increase human monocytes cytokine secretion upon secondary stimulation, a phenomenon now referred as immune training. This ability of monocytes programming confers BGs an undeniable ...[more]

PMID: 28955331

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Project description:The priming of eosinophils by cytokines leading to augmented response to chemoattractants and degranulating stimuli is a characteristic feature of eosinophils in the course of allergic inflammation and asthma. Actin reorganization and integrin activation are implicated in eosinophil priming by GM-CSF, but their molecular mechanism of action is unknown. In this regard, we investigated the role of L-plastin, an eosinophil phosphoprotein that we identified from eosinophil proteome analysis. Phosphoproteomic analysis demonstrated the upregulation of phosphorylated L-plastin after eosinophil stimulation with GM-CSF. Additionally, coimmunoprecipitation studies demonstrated a complex formation of phosphorylated L-plastin with protein kinase C?II (PKC?II), GM-CSF receptor ?-chain, and two actin-associated proteins, paxilin and cofilin. Inhibition of PKC?II with 4,5-bis(4-fluoroanilino)phtalimide or PKC?II-specific small interfering RNA blocked GM-CSF-induced phosphorylation of L-plastin. Furthermore, flow cytometric analysis also showed an upregulation of ?(M)?(2) integrin, which was sensitive to PKC?II inhibition. In chemotaxis assay, GM-CSF treatment allowed eosinophils to respond to lower concentrations of eotaxin, which was abrogated by the above-mentioned PKC?II inhibitors. Similarly, inhibition of PKC?II blocked GM-CSF induced priming for degranulation as assessed by release of eosinophil cationic protein and eosinophil peroxidase in response to eotaxin. Importantly, eosinophil stimulation with a synthetic L-plastin peptide (residues 2-19) phosphorylated on Ser(5) upregulated ?(M)?(2) integrin expression and increased eosinophil migration in response to eotaxin independent of GM-CSF stimulation. Our results establish a causative role for PKC?II and L-plastin in linking GM-CSF-induced eosinophil priming for chemotaxis and degranulation to signaling events associated with integrin activation via induction of PKC?II-mediated L-plastin phosphorylation.

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Dataset Information

Molecular Analysis of a Short-term Model of ?-Glucans-Trained Immunity Highlights the Accessory Contribution of GM-CSF in Priming Mouse Macrophages Response.

Publications

Molecular Analysis of a Short-term Model of β-Glucans-Trained Immunity Highlights the Accessory Contribution of GM-CSF in Priming Mouse Macrophages Response.

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