title: Triggering Dectin-1-Pathway Alone Is Not Sufficient to Induce Cytokine Production by Murine Macrophages.
abstract: β-glucans (BG) are abundant polysaccharides of the Saccharomyces cerevisiae cell wall (Sc CW), an industry byproduct. They have immuno-stimulatory properties upon engagement of dectin-1 (Clec7a), their main receptor on particular immune cells, and they actually become of great interest because of their preventive or therapeutic potentials. Zymosan, a crude extract of Sc CW was studied as a prototypic BG, despite its miscellaneous PAMPs content. Here, we examined the response of murine wild type or Clec7a-/- bone marrow-derived macrophages (BMDM) to products with increasing BG content (15, 65 or 75%) and compared their effects with those of other dectin-1 ligands. The enrichment process removed TLR ligands while preserving dectin-1 activity. The most enriched extracts have very low NFκB activity and triggered low amounts of cytokine production in contrast with crude products like zymosan and BG15. Furthermore, MyD88-/- BMDM did not produce TNFα in response to crude Sc CW extracts, whereas their response to BG-enriched extracts was unaffected, suggesting that BG alone are not able to initiate cytokine secretion. Although Sc CW-derived BG stimulated the late and strong expression of Csf2 in a dectin-1-dependent manner, they remain poor inducers of chemokine and cytokine production in murine macrophages.
authors: Université de Toulouse, INP-ENVT, UMR 1225, IHAP, Toulouse, France.|INRA, UMR1225, IHAP, Toulouse, France.
authors: Sarah
authors: S
authors: Walachowski
authors: Université de Toulouse, INP-ENVT, UMR 1225, IHAP, Toulouse, France.|INRA, UMR1225, IHAP, Toulouse, France.
authors: Guillaume
authors: G
authors: Tabouret
authors: Université de Toulouse, INP-ENVT, UMR 1225, IHAP, Toulouse, France.|INRA, UMR1225, IHAP, Toulouse, France.
authors: Gilles
authors: G
authors: Foucras
mesh_terms: D000818:Animals; D002461:Cell Line, Transformed; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D037181:Lectins, C-Type / Q000096:biosynthesis* / Q000235:genetics; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics; D015398:Signal Transduction; D015054:Zymosan / Q000494:pharmacology; D000099181:Dectin-1
chemical_list: D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D037181:Lectins, C-Type; D053594:Myeloid Differentiation Factor 88; D015054:Zymosan; D000099181:Dectin-1; C507780:Myd88 protein, mouse