Figure 7.

Astrocyte heterogeneity in tubers. (a) Variability in the levels of glutamine synthetase (GS, green) and GFAP (red) in the peripheral portion of a tuber. (b) Microtuber-like areas delineated with vimentin (VIM) immunostaining of astrocytes in a periphery of a tuber. VIM+ giants cells are indicated with arrows. (c,d) Astrocytes revealing features of reactive (high levels of VIM and expression of p44) are composed in small groups in the cenral parts of the tubers. (e-h) Unusual forms of astrocytes in ‘transitional’ areas at the tuber borders. (e) Fibrous-like astrocyte in gliotic tuber parenchyma expressing high levels of GS (red) and EAAT2 (green). Note: 1) main branches of the cell have only small spine-like processes; 2) neighboring gliotic astrocytes (arrowheads, shown only some) express minimal levels of GS and EAAT2. (f) Astrocyte with long straight processes and high level of GS does not show immunoreactivity for SPARC (arrowhead in e1). Giant cell is marked with arrow. (g) EAAT1 immunoreactivity is observed only in astrocyte (arrow) main branches. Note: neighboring astrocyte (double headed arrow) has minimal EAAT1 and GS. (h) Astrocyte with long main branches devoid of EAAT2 immunoreactivity in small leaf-like processes is SPARC immunonegative. (i) Normal protoplasmic astrocyte in normal gray matter. Note abundance of small leaf-like processes almost completely filling the neuropile between main cellular branches. Confocal microscopy double (a,c,e,g) and triple (d,f,h,i) immunostaining, counterstaining with Nissl in cases with double immunostaining. b’ and c’ represent split b and c images, respectively. e1, f1, and h1 enlarged boxed area in e, f, and g, respectively. scale bar: 140 μm in a-d, 70 μm in e,f,h, 45 μm in g,i.