Figure 5.

Elevated AD pathological markers in differentiated neurons with developmental Pb exposure.A, confocal images of mature neurons at Day 45 stained with p-Tau (pThr181-Tau) and DAPI. Scale bar = 50 μm. The relative change of pThr181-tau in neurites was quantified in (B). N ≥ 60 neurites from two independent differentiations. C and D, p-Tau and total Tau expression were examined via Western blot using protein extracts of cortical neurons harvested at Day 45. N = 3 independent differentiations. E, representative FRET images of HEK293T tau biosensor cells treated with culture medium recovered from Pb exposed mature neuron culture at Day 45. F, the FRET intensity of HEK293T tau biosensor cells was quantified and normalized to the unexposed control. N = 8 medium samples harvested from four independent differentiations. The concentrations of Aβ₄₂ (G-top) and Aβ₄₀ (G-middle) in culture medium harvested at Day 45 were quantified via ELISA assays. Ratio of Aβ₄₂/Aβ₄₀ (G-bottom) was calculated based on each sample. N = 8 medium samples harvested from four independent differentiations. H and I, APP expression of cortical neurons harvested at Day 45 were detected and quantified via Western blot. N = 3 independent differentiations. Information of APP and CAMKII was extracted from the same blot, and (H) thus shared the same GAPDH control as 4K. J, illustration of hypothesized molecular pathway altered by developmental Pb exposure conferring increased AD risk. Data = mean ± SE. N.S., not significant; ∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001.