Figure 3
X-gal staining and immunohistochemistry revealed predominant neuronal expression of aminopeptidase P1 in the Xpnpep1+/− hippocampus. (a) Transmitted image of X-gal inclusions in the Xpnpep1+/− CA1 stratum radiatum region was merged with the fluorescence image of DAPI, NeuN, and/or MAP2. (b,c) Combined transmission and fluorescence of images show the presence of X-gal precipitates in the somata and dendrites of Xpnpep1+/− CA1 (b) and CA3 (c) neurons. (d) X-gal precipitates (black) were detected in the GC layer, hilus (polymorphic layer), and outer molecular layer of DG (left). Right, X-gal signals overlapped well with NeuN immunoreactive signals in the DG hilus. (e,f) Left, astrocytes in CA1 (e), and CA3 (f) stratum radiatum from the X-gal (top) stained sections were identified by immunohistochemical staining with GFAP and S100β (bottom). X-gal signals are rarely found in the cell body and processes of Xpnpep1+/− astrocytes (right). (g,h) Cell nuclei, neuronal dendrites, and astrocytic processes in the CA1 (g) and CA3 (h) areas from X-gal stained sections were labeled with DAPI, anti-MAP2, and anti-GFAP antibodies, respectively (left). Right, punctate X-gal signals in the CA1 stratum radiatum (g) and CA3 stratum lucidum (h) were predominantly localized in the MAP2-positive dendrites, but they were occasionally detected in GFAP-positive astrocyte processes. (i,j) Sections were stained with X-gal (left, top), and microglia located in the CA1 (i) and CA3 (j) stratum radiatum were immunostained with Iba1 (left, bottom). The merged images (right) show the absence of β-galactosidase activity in Xpnpep1+/− microglia. (k,l) After X-gal staining (left, top), oligodendrocytes in the CA1 stratum radiatum (k) and stratum oriens (l) were immunolabeled with anti-O4 antibodies (left, bottom). Right, X-gal signals were not observed in the O4-positive cells (arrows). (a–l) DAPI was used to label the nuclei of neurons and glia. Scale bars: 10 µm (j), 20 µm (a–c,e–i,k,l), and 100 µm (d).
