Immunohistochemical localization of phosphoinositide 3-kinase in brains with multiple system atrophy

Oligodendrocytes have been shown to display some morphological characteristics of apoptosis in MSA. The accumulated evidence shows that phosphoinositide 3-kinase (PI3K) is closely associated with the regulation of apoptosis. Thus, we examined immunohistochemically PI3K in the cerebellum and pons from autopsy samples with MSA. In control tissues, PI3K was immunostained in some neurons and a few oligodendrocytes. In MSA samples, the larger number of oligodendrocytes was observed in the pons and cerebellum. Furthermore, some neurons were strongly immunolabeled in MSA samples. The recent study has shown that PI3K phosphorylates PKB/Akt which phosphorylates BAD resulting in the cessation of apoptotic process. The present results suggest that PI3K is upregulated in oligodendrocytes and some neurons in MSA, possibly in response to the apoptotic signals to these cells.