Figure 2.

Immunoreactivity of Aβ and brevican isoforms in APPsw (+) transgenic mice compared to littermate non-transgenic (−) mice. Low power micrograph of immunoreactive Aβ burden in forebrain of 15-16 month old non-transgenic and APPsw mice (A). Hippocampal proteins from 15-16 month old non-transgenic (−)(n=3) and APPsw (+)(n=3) mice were separated on 4-20% SDS-PAGE, transferred to PVDF membrane and probed with anti-Aβ 95-2-5 (B). Note high and low molecular weight Aβ immunoreactivity (arrows). Lane “m” indicates molecular weight markers, lanes “h” are human frontal cortex tissue samples from patients diagnosed with AD, lanes Aβ 10 and Aβ 1 are synthetic Aβ(1-42) at 10 ng and 1 ng per lane respectively (a). Same blot was probed for anti-GAPDH immunoreactivity to normalize for protein loading (b). Identical hippocampal extracts were subjected to Western blot on 4-20% SDS-PAGE gels and probed for anti-brevican, anti-EAMESE and anti-SAHPSA (C). Densitometric semi-quantitative analysis of the western blots in (C) as expressed in arbitrary densitometric units (D). There was no change in abundance of >145 kD brevican protein in hippocampus, although an an identifiable molecular weight shift was apparent in APPsw extract. An increase in the abundance of the core 145 kD brevican (p ≤ 0.05) was accompanied by a decrease in the generalized N-terminal fragment of brevican in APPsw extracts (p ≤ 0.05). A marked decrease in the abundance of the brevican fragment generated by MMP-mediated proteolytic cleavage (p ≤ 0.05) was observed, denoted by anti-SAHPSA immunoreactivity, in hippocampal samples of APPsw mice.