Cross Talk Between Brain Innate Immunity and Serotonin Signaling Underlies Depressive-Like Behavior Induced by Alzheimer's Amyloid-β Oligomers in Mice.

Autor: Ledo, Jose Henrique, Azevedo, Estefania P., Beckman, Danielle, Ribeiro, Felipe C., Santos, Luis E., Razolli, Daniela S., Kincheski, Grasielle C., Melo, Helen M., Bellio, Maria, Teixeira, Antonio L., Velloso, Licio A., Foguel, Debora, De Felice, Fernanda G., Ferreira, Sergio T.
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Zdroj: Journal of Neuroscience; 11/30/2016, Vol. 36 Issue 48, p12106-12116, 11p
Abstrakt: Considerable clinical and epidemiological evidence links Alzheimer's disease (AD) and depression. However, the molecular mechanisms underlying this connection are largely unknown. We reported recently that soluble Aβ oligomers (AβOs), toxins that accumulate in AD brains and are thought to instigate synapse damage and memory loss, induce depressive-like behavior in mice. Here, we report that the mechanism underlying this action involves AβO-induced microglial activation, aberrant TNF-α signaling, and decreased brain serotonin levels. Inactivation or ablation of microglia blocked the increase in brain TNF-α and abolished depressive-like behavior induced by AβOs. Significantly, we identified serotonin as a negative regulator of microglial activation. Finally, AβOs failed to induce depressive-like behavior in Toll-like receptor 4-deficient mice and in mice harboring a nonfunctional TLR4 variant in myeloid cells. Results establish that AβOs trigger depressive-like behavior via a double impact on brain serotonin levels and microglial activation, unveiling a cross talk between brain innate immunity and serotonergic signaling as a key player in mood alterations in AD [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index