Fig. 5.

Aging reconfigures the IL-1 receptor in mouse hippocampal synaptosomes. (A) Hippocampal synaptosomes from young and middle-aged mice were purified by density gradient. Purity was evaluated by Western blot analysis of the synaptic markers synaptophysin (Syp) and PSD95 in nuclear (N) and synaptosome (S) fractions. Expression of astrocyte (glial fibrillary acidic protein; GFAP) and oligodendrocyte (2′,3′-cyclic nucleotide 3′-phosphodiesterase; CNPase) markers was not detected in synaptosome fractions. (B) AcP, AcPb, and IL-1R1 proteins detected by Western blot in hippocampal synaptosome samples. (C) Quantification of AcP, AcPb (n = 11 samples/group), and IL-1R1 (n = 7 samples per group) protein levels in synaptosomes from young (7–8 mo) and middle-aged (13–15 mo) mice. Fresh hippocampi from two mice were pooled for each sample. Values were normalized with corresponding GAPDH levels. AcP and AcPb detection for each sample was performed in duplicate, and values were averaged before statistical analysis. *P < 0.01; ^[*^]P < 0.001 vs. AcPb in young mice (ANOVA, Tukey’s post hoc test). (D) AcP/AcPb protein ratio. *P < 0.05 (Mann–Whitney test). Data are presented as mean ± SEM.