Fig 1: Early re-distribution of the oligodendrocytic connexin (Cx) Cx32 from the membrane to the cytoplasm in multiple system atrophy (MSA). Representative images of a control specimen (myotonic dystrophy) (A–C) and MSA specimens with Stage I (MSA-2) (D–F), II (MSA-3) (G–I), and III disease (MSA-1) (J–L) are illustrated by immunostaining with tubulin polymerization-promoting protein (TPPP/p25a) (A, D, G, J), Cx32 (B, E, H, K), and Cx47 (C, F, I, L). Graphs show the percentage of TPPP/p25a- (U), Cx32- (V), and Cx47-positive (W) areas in myelin fibers. TPPP/p25a, Cx32, and Cx47 were localized at the cellular membranes of oligodendrocytic somata and myelin in the cerebellar afferent fibers in the control specimen (A–C). In Stage I MSA, TPPP/p25a and Cx32 were extensively absent from the cellular membrane of oligodendrocyte somata and myelin and highly re-distributed into the cytoplasm (D–E, U, V). Re-distribution of these proteins was consistently seen in Stages II and III (G, H, J, K). Another oligodendrocytic Cx, Cx47, was also gradually decreased in a stage-dependent manner but not re-distributed into the cytoplasm in all stages (F, I, L, W). Double immunofluorescence detection of phosphorylated a-synuclein (p-aSyn) and oligodendrocytic Cx32 in Stage I cerebellar afferent fibers demonstrated that Cx32 was highly co-localized with p-aSyn-positive glial cytoplasmic inclusions (GCIs) (M–P). Even in Stage III, the remaining p-aSyn-positive GCIs were co-localized with Cx32 (Q–T). A graph shows the quantification of the co-localization ratio of p-aSyn and Cx32 (X). Scale bars: 25 µm (A–L), 10 µm (M–T). Graphs display the mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001