Figure 7. Neuroprotective effect of polySia with average degree of polymerization 20.

(a) Co-culture of human macrophages and neurons. Cells were double-immunostained with antibodies directed against the macrophage marker CD11b and the neuronal marker neurofilament. Nuclei were labelled by DAPI. Co-cultures were treated with fibrillary amyloid-β_1–42 and polySia avDP20 plus fibrillary amyloid-β_1–42. Loss of neurites observed in amyloid-β_1–42 treated co-cultures was prevented by addition of polySia avDP20. Scale bar: 50 μm. (b) Relative neurite length of human neurons was determined with or without addition of THP1 macrophages and/or fibrillary amyloid-β_1–42 after 48 hours. Addition of amyloid-β_1–42 alone did not affect the relative neurite length. Treatment of macrophage-neuron co-culture with amyloid-β_1–42 further reduced the relative neurite length. Data are presented as mean +/− SEM of n = 3 independent experiments. *p < 0.05; ANOVA followed by Bonferroni. (c) Relative neurite length of human neurons in macrophage-neuron co-culture. The co-culture was incubated with fibrillary amyloid-β_1–42 and/or polySia avDP20. The amyloid-β_1–42 induced reduction in the relative neurite length was antagonized by polySia avDP20. Data are presented as mean +/− SEM of n = 3 independent experiments. *p < 0.05; ANOVA followed by Bonferroni.