14-3-3 proteins in Lewy bodies in Parkinson disease and diffuse Lewy body disease brains.

Several components of Lewy bodies have been identified, but the precise mechanism responsible for the formation of Lewy bodies remains undetermined. The 14-3-3 protein family is involved in numerous signal transduction pathways and interacts with α-synuclein, which is a major constituent of Lewy bodies. To elucidate the role of 14-3-3 proteins in neurodegenerative disorders associated with Lewy bodies, we performed immunohistochemical studies on 14-3-3 in brains from 5 elderly control subjects and from 10 patients with Parkinson disease (PD) or diffuse Lewy body disease (DLBD). In the normal controls, 14-3-3-like immunoreactivity was mainly observed in the neuronal somata and processes in various cortical and subcortical regions. In the PD and DLBD cases, a similar immunostaining pattern was found and immunoreactivity was generally spared in the surviving neurons from the severely affected regions. In addition, both classical and cortical Lewy bodies were intensely immunolabeled and some dystrophic neurites were also immunoreactive for 14-3-3. Our results suggest that 14-3-3 proteins may be associated with Lewy body formation and may play an important role in the pathogenesis of PD and DLBD.