title: Nucleotides released from Aβ₁₋₄₂ -treated microglial cells increase cell migration and Aβ₁₋₄₂ uptake through P2Y₂ receptor activation.
abstract: Amyloid β-protein (Aβ) deposits in brains of Alzheimer's disease patients generate proinflammatory cytokines and chemokines that recruit microglial cells to phagocytose Aβ. Nucleotides released from apoptotic cells activate P2Y(2) receptors (P2Y(2) Rs) in macrophages to promote clearance of dead cells. In this study, we investigated the role of P2Y(2) Rs in the phagocytosis and clearance of Aβ. Treatment of mouse primary microglial cells with fibrillar (fAβ(1-42) ) and oligomeric (oAβ(1-42) ) Aβ(1-42) aggregation solutions caused a rapid release of ATP (maximum after 10 min). Furthermore, fAβ(1-42) and oAβ(1-42) treatment for 24 h caused an increase in P2Y(2) R gene expression. Treatment with fAβ(1-42) and oAβ(1-42) aggregation solutions increased the motility of neighboring microglial cells, a response inhibited by pre-treatment with apyrase, an enzyme that hydrolyzes nucleotides. The P2Y(2) R agonists ATP and UTP caused significant uptake of Aβ(1-42) by microglial cells within 30 min, which reached a maximum within 1 h, but did not increase Aβ(1-42) uptake by primary microglial cells isolated from P2Y(2) R(-/-) mice. Inhibitors of α(v) integrins, Src and Rac decreased UTP-induced Aβ(1-42) uptake, suggesting that these previously identified components of the P2Y(2) R signaling pathway play a role in Aβ phagocytosis by microglial cells. Finally, we found that UTP treatment enhances Aβ(1-42) degradation by microglial cells, but not in cells isolated from P2Y(2) R(-/-) mice. Taken together, our findings suggest that P2Y(2) Rs can activate microglial cells to enhance Aβ clearance and highlight the P2Y(2) R as a therapeutic target in Alzheimer's disease.
authors.affiliation: Department of Biochemistry, University of Missouri, Columbia, Missouri, USA.
authors.forename: Hye Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Deepa
authors.initials: D
authors.lastname: Ajit
authors.forename: Troy S
authors.initials: TS
authors.lastname: Peterson
authors.forename: Yanfang
authors.initials: Y
authors.lastname: Wang
authors.forename: Jean M
authors.initials: JM
authors.lastname: Camden
authors.forename: W
authors.initials: W
authors.lastname: Gibson Wood
authors.forename: Grace Y
authors.initials: GY
authors.lastname: Sun
authors.forename: Laurie
authors.initials: L
authors.lastname: Erb
authors.forename: Michael
authors.initials: M
authors.lastname: Petris
authors.forename: Gary A
authors.initials: GA
authors.lastname: Weisman
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000378:metabolism* / Q000633:toxicity*; D000818:Animals; D015153:Blotting, Western; D002465:Cell Movement / Q000187:drug effects*; D002469:Cell Separation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D039482:Integrin alpha5 / Q000494:pharmacology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D009454:Neurofibrils / Q000378:metabolism; D009711:Nucleotides / Q000378:metabolism* / Q000494:pharmacology*; D010446:Peptide Fragments / Q000378:metabolism* / Q000633:toxicity*; D010587:Phagocytosis / Q000187:drug effects; D058912:Purinergic P2Y Receptor Agonists; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D058473:Receptors, Purinergic P2Y2 / Q000187:drug effects*; D014544:Uridine Triphosphate / Q000494:pharmacology; D020744:rac GTP-Binding Proteins / Q000502:physiology; D019061:src-Family Kinases / Q000502:physiology
chemical_list: D016229:Amyloid beta-Peptides; D039482:Integrin alpha5; D009711:Nucleotides; D010446:Peptide Fragments; D058912:Purinergic P2Y Receptor Agonists; D012333:RNA, Messenger; D058473:Receptors, Purinergic P2Y2; C075222:amyloid beta-protein (1-42); D000255:Adenosine Triphosphate; D007770:L-Lactate Dehydrogenase; D019061:src-Family Kinases; D020744:rac GTP-Binding Proteins; D014544:Uridine Triphosphate