Figure 4.

HuCNS-SCs Fail to Improve Learning and Memory in Rag-5xfAD Mice

(A) Analysis of Morris water maze (MWM) learning curve demonstrates that vehicle-injected Rag-5xfAD mice (green squares) take significantly longer to find the platform compared with vehicle-injected Rag-WT mice (blue circles). Thus, Rag-5xfAD mice exhibit characteristic AD-associated impairments in MWM performance. Transplantation of HuCNS-SCs provides no improvement in MWM performance as HuCNS-SC-injected Rag-5xfAD mice (green triangles) perform no better than vehicle-injected Rag-5xfAD mice (green squares).

(B) Rag-5xfAD mice regardless of treatment were also significantly impaired in a novel arm Y-maze test of spatial working memory, spending a smaller percentage of their time in the novel arm.

(C) Analysis of anxiety in elevated plus maze (EPM) revealed no differences between Rag-5xfAD and Rag-WT animals receiving vehicle injections. However, Rag-5xfAD (HuCNS-SC) animals were significantly less anxious than Rag-WT (HuCNS-SC) animals, suggesting that HuCNS-SCs may promote impaired EPM performance.

(D and E) ELISA analysis of hippocampal lysates revealed no difference in Aβ40 or Aβ42 levels regardless of treatment in Rag-5xfAD mice.

(F) HuCNS-SC transplantation also failed to elevate hippocampal BDNF protein levels and surprisingly produced a non-significant trend toward decreased BDNF (p = 0.21).

(G–J) Representative high-power confocal images of presynaptic PSD-95 labeling in the stratum oriens of the hippocampus.

(K) As previously reported in AD mouse models, quantification of PSD-95 density revealed a significant reduction in postsynaptic terminals in vehicle-treated Rag-5xfAD versus vehicle-treated Rag-WT mice. However, no increase in PSD95 density was detected after HuCNS-SC transplantation. Instead, delivery of HuCNS-SCs led to a significant further reduction of PSD95 in Rag5xfAD mice and reduced postsynaptic puncta in Rag-WT mice. ANOVA p < 0.05 and Fisher's PLSD post hoc ^∗p < 0.05, #p < 0.001. Aβ and BDNF; PSD95 N ≥ 6 animals/group. Data presented as means ± SEM. ANOVA p < 0.05 and Fisher's PLSD post hoc. N ≥ 6 animals/group (B–C), N ≥ 4 animals/group (D–F), (K) N ≥ 6 animals/group. Value for each animal was an average of five randomly selected regions of interest within images of the stratum oriens of two different brain sections (total of ten measurements). (A) ^∗p < 0.05 between Rag-WT (Vehicle) and Rag-5xfAD (Vehicle) and #p < 0.05 between Rag-WT (Vehicle) and Rag-5xfAD (HuCNS-SC). (B, C, and K) ^∗p < 0.05, §p < 0.01, #p < 0.001.

Scale bar, 10 μm.