(A - F) Photomicrographs of BrdU (green or yellow)+ cells in the DG of PS1hWT (A, D), PS1ΔE9 (B, E) and PS1M146L (C, F). SH, standard housing conditions (A, B, C); EE, enriched conditions (D, E, F). NeuN, red. Scale bar: 100 μm.
(G) Quantification of BrdU+ cells (mean ± SEM; N = 10 - 15 per group). * P < 0.05.
(H) Quantification of granule cell number. * P < 0.05.
(I) Photomicrograph of primary neurospheres. Scale bar: 50 μm.
(J) Image of nestin (green)+ neurosphere. Scale bar: 25 μm.
(K) Nuclei were stained with DAPI (blue).
(L) Percentage of multipotent neurospheres obtained in clonogenic neurosphere assay (mean ± SEM, N = 5 animals per group). ** P < 0.01.

(A - E) Images of BrdU+ cells that are colabeled with either DCX (A), βIII-tubulin (B), NeuN (C), GFAP (D) or s100β (E). Scale bar: 50 μm (A, B, D, and E) or 100 μm (C). (F, H, J, L, N) The fraction of BrdU+ cells that expressed DCX (F), βIII-tubulin (H), NeuN (J), GFAP (L), or s100β (N).
(G, I, K, M, O) The number of new DCX (G)-, βIII-tubulin (I)-, NeuN (K)-, GFAP (M)-, or s100β (O)-cells. * P < 0.05; ** P < 0.01. N = 8 per group.

(A - L) Images of microglia in DG of standard PS1hWT (A, B, and C), highly active PS1hWT (D, E, and F), highly active PS1M146L (G, H, and I), and highly active PS1hWT (high magnification, J, K, and L). Microglia are labeled with IB-4 (green; A, D, G, and J) and Iba1 (red; B, E, H, and K). Merged images are shown in (C, F, I, and L). Scale bars: 100 μm in A; 50 μm in J.
(M) Quantification of Iba1+ cells in standard or enriched PS1hWT and FAD-linked PS1 variants (mean ± SEM; N = 10 - 15 per group).
(N) Quantification of Iba1+ cells in highly active or low active PS1hWT and FAD-linked PS1 variants. * P < 0.05.

(A) Proliferation achieved by NPCs, expressing PS1hWT, PS1ΔE9 or PS1M146L, grown in SFM supplemented with BrdU (mean ± SEM from a minimum of three experiments per group).
(B - D) IB-4+ microglial cells (B, green) and nestin+ NPCs (C, red) under co-culture conditions. The merged image is shown in D. Fibrillar staining of the intermediate filament protein, Nestin, is evident on NPCs (arrow head) but not on microglial cells (arrow). Scale bar: 10 μm.
(E - F) Proliferation of PS1hWT NPCs when co-cultured with AraC-treated resting (E) or IL4-activated (F) microglia (MG) expressing PS1hWT, PS1ΔE9 or PS1M146L as measured by BrdU labeling. ** indicates significant difference from PS1hWT MG at P < 0.01 on day 3 or 6.
(G - J) Confocal z-series reconstructed image of cells stained with IB-4 (G), anti-nestin (H), anti-BrdU antibody (I) and DAPI (J), following 6 days under co-culturing conditions.
(K - N) Confocal images of a single z-plane within nestin+ neural progenitor cluster (K; red, arrow head) reveals several BrdU+ progenitors (K; cyan blue, enclosed within circle) and an IB-4+ MG (K; green, arrow). Insert shows the zoom-in area marked within dotted square (L). Scale bar: 50 μm.
(M - N) Zoomed images of cells that are co-labeled with BrdU/nestin (M) or BrdU/IB-4 (N). Scale bar: 10 μm.
(O - P) Quantification of BrdU and nestin (O) or BrdU and IB-4 (P) co-labeled cells in the co-culture assay. The asterisk indicates significant difference from PS1hWT MG at * P < 0.05 and ** P < 0.01.

(A - B) Proliferation achieved by PS1hWT NPCs following treatment with conditioned media collected from resting (A) or IL4-activated (B) microglia (MG) expressing mentioned PS1 transgenes, as measured by BrdU labeling. ** indicates significant difference from PS1hWT MG media at P < 0.01 on day 3 or 6.

(A) Progeny cell types generated by NPCs in the multipotency assay were quantified by sampling a minimum of 300 cells as marked by DAPI or propidium iodide+ nuclei (mean ± SEM of the results obtained from independent cultures established from 6 animals per group).
(B) Fold changes in the number of βIII-tubulin+ neuronal or GFAP+ astrocyte progeny cell type derived from PS1hWT NPCs exposed to CM collected from resting or IL4-activated MG, over differentiated PS1hWT NPC cultures in the absence of MG CM (mean ± SEM; N = 6). The asterisk indicates significant difference from PS1hWT MG CM at * P < 0.05 and ** P < 0.01.

(A) Images of biotin-label based protein antibody arrays probed with CM collected from resting or IL4-activated microglia (MG).
(B) Soluble factors whose levels were consistently altered (up or down ‘-’; mean ± SEM of fold changes observed across three experiments). - denotes, no detectable change in mean signal intensity.