Suchergebnisse

Alzheimer's disease (AD) is a progressive neurodegenerative disease in which the formation of extracellular aggregates of amyloid beta (Aβ) peptide, fibrillary tangles of intraneuronal tau and microglial activation are major pathological hallmarks. One of the key molecules involved in microglial activation is galectin-3 (gal3), and we demonstrate here for the first time a key role of gal3 in AD pathology. Gal3 was highly upregulated in the brains of AD patients and 5xFAD (familial Alzheimer's disease) mice and found specifically expressed in microglia associated with Aβ plaques. Single-nucleotide polymorphisms in the LGALS3 gene, which encodes gal3, were associated with an increased risk of AD. Gal3 deletion in 5xFAD mice attenuated microglia-associated immune responses, particularly those associated with TLR and TREM2/DAP12 signaling. In vitro data revealed that gal3 was required to fully activate microglia in response to fibrillar Aβ. Gal3 deletion decreased the Aβ burden in 5xFAD mice and improved cognitive behavior. Interestingly, a single intrahippocampal injection of gal3 along with Aβ monomers in WT mice was sufficient to induce the formation of long-lasting (2 months) insoluble Aβ aggregates, which were absent when gal3 was lacking. High-resolution microscopy (stochastic optical reconstruction microscopy) demonstrated close colocalization of gal3 and TREM2 in microglial processes, and a direct interaction was shown by a fluorescence anisotropy assay involving the gal3 carbohydrate recognition domain. Furthermore, gal3 was shown to stimulate TREM2–DAP12 signaling in a reporter cell line. Overall, our data support the view that gal3 inhibition may be a potential pharmacological approach to counteract AD. ; This work was supported by Grants from the Swedish Research Council, and the Strong Research Environment MultiPark (Multidisciplinary Research in Parkinson's and Alzheimer's Disease at Lund University), Bagadilico (Linné consortium sponsored by the Swedish Research Council), the Swedish Alzheimer's Foundation, Swedish Brain Foundation, A.E. Berger Foundation, Gyllenstiernska Krapperup Foundation, the Royal Physiographic Society, Crafoord Foundation, Olle Engkvist Byggmästare Foundation, Wiberg Foundation, G&J Kock Foundation, Stohnes Foundation, Swedish Dementia Association and the Medical Faculty at Lund University. This work was supported by Grant SAF2015-64171R (Spanish MINECO/FEDER, UE), by Instituto de Salud Carlos III (ISCiii) of Spain, co-financed by FEDER funds from European Union through grants PI15/00796 and PI18/01557 (to AG), PI15/00957 and PI18/01556 (to JV), and CIBERNED (to AG and JV), by Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucia Proyecto de Excelencia (CTS-2035) (to JV and AG), and by Malaga University grant PPIT.UMA.B1.2017/26 (to RSV). AV and GCB received funding from the Innovative Medicines Initiative 2 Joint Undertaking under Grant agreement no. 115976 (PHAGO). CIBERNED "Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid (Spain)". HL and AF were supported by the Swedish Research Council, the Swedish Brain Foundation, the Alzheimer Foundation and the Åhlén Foundation. UJN was supported by Grants from the Knut and Alice Wallenberg Foundation (KAW 2013.0022) and the Swedish Research Council (Grant no. 621-2012-2978). ; Peer reviewed