title: Effects of Toll-like receptor ligands on RAW 264.7 macrophage morphology and zymosan phagocytosis.
abstract: In this study we compared the effects of the Toll-like receptor (TLR) ligands lipopolysaccharide (LPS), flagellin, the synthetic bacterial triacylated lipopeptide Pam3-Cys-Ser-Lys4 (Pam3CSK4), Polyinosinic:polycytidylic acid (Poly I:C), and macrophage-activating lipopeptide (MALP-2), which are TLR4, TLR5, TLR1/2, TLR3, and TLR2/6 agonists, respectively, on cell morphology and phagocytosis of zymosan particles, derived from Saccharomyces cerevisiae, and rich in fungal PAMPs including beta-glucan, mannose, and chitin. LPS, Pam3CSK4, and MALP-2 induced an activated macrophage phenotype and enhanced zymosan phagocytosis. In contrast, flagellin and Poly I:C, respectively, had little effect on cell morphology and phagocytosis. We examined the role of scavenger receptor A (SR-A) on zymosan phagocytosis. Cells cultured in medium alone expressed SR-A, and LPS induced further expression of the receptor. We also observed inhibitory effects of scavenger receptor antagonists fucoidan, dextran sulphate, and Polyinosinic (Poly I), respectively, on zymosan phagocytosis of cells in medium alone and those pre-treated with LPS. We conclude that exposure to specific TLR ligands impacts both cellular morphology and phagocytic capacity, and that scavenger receptors contribute to zymosan ingestion as well as LPS-induced augmentation of phagocytosis.
authors.affiliation: Biology Department, Douglas College, P.O. Box 2503, New Westminster B.C. V3L 5B2, Canada. Electronic address: sigolal@douglascollege.ca.
authors.forename: Lynette B
authors.initials: LB
authors.lastname: Sigola
authors.affiliation: Biology Department, Douglas College, P.O. Box 2503, New Westminster B.C. V3L 5B2, Canada.
authors.forename: Ana-Lucía
authors.initials: AL
authors.lastname: Fuentes
authors.affiliation: Biology Department, Douglas College, P.O. Box 2503, New Westminster B.C. V3L 5B2, Canada.
authors.forename: Leonard M
authors.initials: LM
authors.lastname: Millis
authors.affiliation: Faculty of Health Sciences, Douglas College, P.O. Box 2503, New Westminster B.C. V3L 5B2, Canada.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Vapenik
authors.affiliation: Department of Molecular Biology and Biochemistry, Simon Fraser University, 8888 University Drive, Burnaby, B.C. V5A 1S6 Canada.
authors.forename: Armstrong
authors.initials: A
authors.lastname: Murira
mesh_terms: D000818:Animals; D005408:Flagellin / Q000494:pharmacology; D008024:Ligands; D055666:Lipopeptides / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D010587:Phagocytosis / Q000187:drug effects* / Q000235:genetics; D000067996:RAW 264.7 Cells / Q000187:drug effects / Q000648:ultrastructure; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000235:genetics* / Q000378:metabolism; D015054:Zymosan / Q000737:chemistry / Q000378:metabolism
chemical_list: D008024:Ligands; D055666:Lipopeptides; D008070:Lipopolysaccharides; C508075:Pam(3)CSK(4) peptide; D051193:Toll-Like Receptors; D005408:Flagellin; D015054:Zymosan; C106335:macrophage stimulatory lipopeptide 2
keywords: Macrophage; Morphology; Phagocytosis; Scavenger receptor; Toll-like receptor; Zymosan