WNT signaling in microglia : WNTs as novel regulators of microglia

摘要: Microglia, the immunocompetent cells of central nervous system (CNS) and brain’s own macrophages are most motile in CNS those with highest plasticity, as they rapidly move their projections to actively screen environment for any type injury. Upon cell damage or infection, microglia respond quickly: proliferate, change morphology from ramified amoeboid state migrate invade towards injury, secrete many types cytokines chemokines communicate other inflammatory cells, phagocytose debris. WNTs secreted lipoglycoproteins, which bind act through Frizzled family receptors. The (FZD) surface receptors belong a seven transmembrane listed G protein-coupled because structural similarities. WNT/FZD-signaling was historically divided into two main branches pathways, depending whether not induce β-catenin stabilization. With increasing knowledge WNT pathways mainly named after protein-induced intracellular events. WNT/FZDsignaling is important during embryonic development, neurogenesis, synaptogenesis, tissue homeostasis. Even though expressed brain definitely contact link between has just recently begun emerge. aim this thesis study how stimulation recombinant regards WNT-induced signaling physiological outcome. We have investigated by use classical biochemical techniques, such immunoblotting, immunochemistry, RT/QPCR, GDP/GTP exchange assay proliferation assay. results show that primary isolated mice microglia-like line (N13) express several stimulation. Stimulation WNT-3A induced WNT/β-catenin-dependent pathway, and, parallel, GPCR pathway leading phosphorylation MAPKs ERK1/2. Interestingly, Gαi/o protein inhibitor, pertussis toxin (PTX), we pinpoint role heterotrimeric proteins both WNT-3A-induced pathways. Further, WNT-5A MAPK recruiting Gαi/o-protein, PKC, calcium MEK1/2 phosphorylate In addition, substantial proinflammatory response expression cytokines, prostaglandin synthase COX2, invasion. Notably, some these markers could be inhibited PTX pointing protein-dependent mechanism. Furthermore, Alzheimer’s disease, chronic neuroinflammatory condition associated activated microglia, amoeboid-like high levels β-catenin, suggesting WNT/β-catenin plays an AD-associated activation. COX2 dose-dependently, but if preactivated bacterial wall derivate lipopolysaccharide (LPS), counteract LPS-induced COX-2 expression. This suggests dual regulatory, i. e. pro-and anti-inflammatory effect on microglia. conclusion, impact microglia’s activity; may play roles modulators activity neuroinflammation LIST OF PUBLICATIONS I. Halleskog C., Mulder J, Dahlstrom Mackie K, Hortobagyi T, Tanila H, Kumar Puli L, Farber Harkany Schulte G. (2011) proinflammatory. Glia. 59: 119-131. II. (2013) Pertussis toxin-sensitive G(αi/o) mediate WNT/ERK1/2 mouse stimulated purified WNT-3A. Cellular Signalling. 25: 822-828 III. Kilander MBC, Recombinant differentially activate β-catenin-dependent -independent signalling cells. Acta Physiologica (Oxf). 203: 363-372. IV. Dijksterhuis JP, MB, Becerril-Ortega Villaescusa JC, Lindgren E, Arenas (2012) Heterotrimeric ERK1/2 mediates distinct aspects transformation. Journal Neuroinflammation.9: 111. V. LPSinduced changes Neurochemistry. Doi: 10.1111/jnc.12250. All previously published papers were reproduced permission publisher.