Neuroinflammation induced by amyloid beta 25-35 modifies mucin-type O-glycosylation in the rat's hippocampus

摘要

Amyloid-beta (A beta) plays a relevant role in the neurodegenerative process of Alzheimer's disease (AD). The 25-35 peptide of amyloid-beta (A beta 5-35) induces the inflammatory response in brain experimental model's. Mucin-type O-glycosylation has been associated with inflammation of brain tissues in AD, thus in this work, we aimed at identifying changes in the glycosylation profile generated by the injection of A beta 25-35 into the CA1 of the hippocampus of rats, using histochemistry with lectins. Our results indicate that 100 mu M A beta 25-35 induce increased recognition of the Amaranthus leucoccupus lectin (ALL) (specific for Gal beta 1,3-GalNAc alpha 1,0-Ser/Thr); whereas concanavalin A (Con A) (specific for alpha-Man) showed no differences among treated and control groups of rats. Jacalin and peanut agglutinin (Gal beta 1,3GalNAc alpha 1,0-Ser/Thr) showed no recognition of brain cells of control or treated rats. After 6-h treatment of the tissue with trypsin or with 200 mM GalNAc, the interaction with ALL was inhibited. Immunohistochemistry showed positive anti-NeuN and ALL-recognition of neurons; however, anti-GFAP and anti-CD11b showed no co-localization with ALL. The ALL + neurons revealed the presence of cytochrome C in the cytosol and active caspase 3 in the cytosol and nucleus. Administration of the interleukin-1 receptor antagonist (IL-1RA) to A beta 25-35-treated rats diminished neuroinflammation and ALL recognition. These results suggest a close relationship among over-expression of mucin-type O-glycosylation, the neuroinflammatory process, and neuronal death.