title: Omega-3 fatty acids enhance phagocytosis of Alzheimer's disease-related amyloid-β42 by human microglia and decrease inflammatory markers.
abstract: The use of supplements with omega-3 (ω3) fatty acids (FAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) is widespread due to proposed beneficial effects on the nervous and cardiovascular systems. Many effects of ω3 FAs are believed to be caused by down-regulation and resolution of inflammation. Alzheimer's disease (AD) is associated with inflammation mediated by microglia and astrocytes, and ω3 FAs have been proposed as potential treatments for AD. The focus of the present study is on the effects of DHA and EPA on microglial phagocytosis of the AD pathogen amyloid-β (Aβ), on secreted and cellular markers of immune activity, and on production of brain-derived neurotrophic factor (BDNF). Human CHME3 microglial cells were exposed to DHA or EPA, with or without the presence of Aβ42. Phagocytosis of Aβ42 was analyzed by flow cytometry in conjunction with immunocytochemistry using antibodies to cellular proteins. Secreted proteins were analyzed by ELISA. Both DHA and EPA were found to stimulate microglial phagocytosis of Aβ42. Phagocytosis of Aβ42 was performed by microglia with a predominance of M2 markers. EPA increased the levels of BDNF in the culture medium. The levels of TNF-α were decreased by DHA. Both DHA and EPA decreased the pro-inflammatory M1 markers CD40 and CD86, and DHA had a stimulatory effect on the anti-inflammatory M2 marker CD206. DHA and EPA can be beneficial in AD by enhancing removal of Aβ42, increasing neurotrophin production, decreasing pro-inflammatory cytokine production, and by inducing a shift in phenotype away from pro-inflammatory M1 activation.
authors.affiliation: Division of Neurodegeneration, Department of Neurobiology, Care Sciences & Society, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Hjorth
authors.forename: Mingqin
authors.initials: M
authors.lastname: Zhu
authors.forename: Veronica Cortés
authors.initials: VC
authors.lastname: Toro
authors.forename: Inger
authors.initials: I
authors.lastname: Vedin
authors.forename: Jan
authors.initials: J
authors.lastname: Palmblad
authors.forename: Tommy
authors.initials: T
authors.lastname: Cederholm
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Freund-Levi
authors.forename: Gerd
authors.initials: G
authors.lastname: Faxen-Irving
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Wahlund
authors.forename: Hans
authors.initials: H
authors.lastname: Basun
authors.forename: Maria
authors.initials: M
authors.lastname: Eriksdotter
authors.forename: Marianne
authors.initials: M
authors.lastname: Schultzberg
mesh_terms: D000544:Alzheimer Disease / Q000276:immunology*; D016229:Amyloid beta-Peptides / Q000276:immunology*; D051940:B7-2 Antigen / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000096:biosynthesis; D019013:CD40 Antigens / Q000378:metabolism; D002460:Cell Line; D004281:Docosahexaenoic Acids / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000473:pathology*; D016753:Interleukin-10 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D017628:Microglia / Q000187:drug effects / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology*; D010587:Phagocytosis / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016229:Amyloid beta-Peptides; D051940:B7-2 Antigen; D019208:Brain-Derived Neurotrophic Factor; D019013:CD40 Antigens; D015525:Fatty Acids, Omega-3; D015850:Interleukin-6; D010446:Peptide Fragments; D014409:Tumor Necrosis Factor-alpha; C075222:amyloid beta-protein (1-42); D016753:Interleukin-10; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid