title: Immunomodulation by 17beta-estradiol in bivalve hemocytes.
abstract: In mammals, estrogens have dose- and cell-type-specific effects on immune cells and may act as pro- and anti-inflammatory stimuli, depending on the setting. In the bivalve mollusc Mytilus, the natural estrogen 17beta-estradiol (E(2)) has been shown to affect neuroimmune functions. We have investigated the immunomodulatory role of E(2) in Mytilus hemocytes, the cells responsible for the innate immune response. E(2) at 5-25 nM rapidly stimulated phagocytosis and oxyradical production in vitro; higher concentrations of E(2) inhibited phagocytosis. E(2)-induced oxidative burst was prevented by the nitric oxide (NO) synthase inhibitor N(G)-monomethyl-L-arginine and superoxide dismutase, indicating involvement of NO and O(2)(-); NO production was confirmed by nitrite accumulation. The effects of E(2) were prevented by the antiestrogen tamoxifen and by specific kinase inhibitors, indicating a receptor-mediated mechanism and involvement of p38 MAPK and PKC. E(2) induced rapid and transient increases in the phosphorylation state of PKC, as well as of a aCREB-like (cAMP responsive element binding protein) transcription factor, as indicated by Western blot analysis with specific anti-phospho-antibodies. Localization of estrogen receptor-alpha- and -beta-like proteins in hemocytes was investigated by immunofluorescence confocal microscopy. The effects of E(2) on immune function were also investigated in vivo at 6 and 24 h in hemocytes of E(2)-injected mussels. E(2) significantly affected hemocyte lysosomal membrane stability, phagocytosis, and extracellular release of hydrolytic enzymes: lower concentrations of E(2) resulted in immunostimulation, and higher concentrations were inhibitory. Our data indicate that the physiological role of E(2) in immunomodulation is conserved from invertebrates to mammals.
authors.affiliation: Istituto di Scienze Fisiologiche, Università Carlo Bo di Urbino, Italy. Laura.Canesi@unige.it
authors.forename: Laura
authors.initials: L
authors.lastname: Canesi
authors.forename: Caterina
authors.initials: C
authors.lastname: Ciacci
authors.forename: Lucia Cecilia
authors.initials: LC
authors.lastname: Lorusso
authors.forename: Michele
authors.initials: M
authors.lastname: Betti
authors.forename: Tiziana
authors.initials: T
authors.lastname: Guarnieri
authors.forename: Simona
authors.initials: S
authors.lastname: Tavolari
authors.forename: Gabriella
authors.initials: G
authors.lastname: Gallo
mesh_terms: D000818:Animals; D050882:CREB-Binding Protein / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology*; D006434:Hemocytes / Q000187:drug effects* / Q000276:immunology*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors; D049878:Mytilus / Q000201:enzymology* / Q000276:immunology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011960:Receptors, Estrogen / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D011960:Receptors, Estrogen; D014409:Tumor Necrosis Factor-alpha; D004958:Estradiol; D050882:CREB-Binding Protein; D011493:Protein Kinase C; D020929:Mitogen-Activated Protein Kinase Kinases