Influence of RNA interference on the mitochondrial subcellular localization of alpha-synuclein and on the formation of Lewy body-like inclusions in the cytoplasm of human embryonic kidney 293 cells induced by the overexpression of alpha-synuclein.

The specific and effective α-synuclein RNA interference (RNAi) plasmids, and the α-synuclein-pEGFP recombinant plasmids were co-transfected into human embryonic kidney 293 (HEK293) cells using the lipofectamine method. Using an inverted fluorescence microscope, α-synuclein proteins were observed to aggregate in the cytoplasm and nucleus. Wild-type α-synuclein proteins co-localized with mitochondria. Hematoxylin-eosin staining revealed round eosinophilic bodies (Lewy body-like inclusions) in the cytoplasm of some cells transfected with α-synuclein-pEGFP plasmid. However, the formation of Lewy body-like inclusions was not observed following transfection with the RNAi pSYN-1 plasmid. RNAi blocked Lewy body-like inclusions in the cytoplasm of HEK293 cells induced by wild-type α-synuclein overexpression, but RNAi did not affect the subcellular localization of wild-type α-synuclein in mitochondria.