Acute synaptotoxicity at earlier time points of M1000 prion disease is associated with PK-sensitive prion protein species.

(A) Western blotting of 20μL of preparations obtained following immuno-precipitation of total PrP species from 1% (w/v) crude M1000 brain homogenates (cM1000) from 30%, 50%, 70%, and 100% of M1000 disease progression to the terminal stage of disease (TSD; in WT C57BL6J mice) and mild PK digestion (probed with 8H4; molecular weight markers are provided at left). (B) Quantification of at least modestly PK-resistant PrP species obtained in A (by densitometry analysis) with the levels of PrP in each PK-eluted immuno-precipitated M1000 preparation (PK+IP-M1000) compared across the time points (One-way ANOVA with Tukey’s correction for multiple comparisons). (C to F) LTP of WT mouse hippocampal slices following a five minute treatment with 0.5% (w/v in aCSF) PK+IP-M1000 from 30% (C), 50% (D), 70% (E), and 100% (F) of the TSD compared with LTP of slices treated with 0.5% (w/v in aCSF) PK-eluted immuno-precipitated normal brain homogenate (PK+IP-NBH) controls (One-way ANOVA with Dunnett’s correction for multiple comparisons). (G) The average LTPs, (H) the average percentage of PPF ratio decline, and (I) the average PTPs generated by WT mouse hippocampal slices treated with PK+IP-NBH and PK+IP-M1000 from across time points of the disease progression (compared by One-way ANOVA with Dunnett’s correction for multiple comparisons). (C-F) The 5 minute treatment started after 8–to-10 minutes of stable baseline. The high frequency stimulation (HFS) trains were applied following 30 minutes of baseline recordings. Results are presented as mean ± standard error of mean. (C-F, H & I) Some examples of raw fEPSP traces are provided as insets. *p.05, ****p.0001, ns = not statistically significant (p>0.05).