Ultrastructural changes in peripheral blood leukocytes in α-synuclein knockout mice

Effects of α-synuclein deficiency on cellular blood components have not been extensively investigated. This study evaluated ultrastructural changes of leukocytes in α-synuclein knockout (KO) mice using electron microscopy (EM). The following ultrastructural characteristics were quantified in leukocytes: mitochondria, primary granules, specific granules (SG), Golgi apparatus (GA), inclusions, rough-endoplasmic reticulum (RER), smooth-endoplasmic reticulum (SER), and cellular projections (CP). EM showed increased numbers or amounts of SG, inclusions, and SER in KO group (5.3 ± 4.5 in WT vs. 14.1 ± 10.3 in KO, p = 0.02; 0.4 ± 0.9 in WT vs. 3.2 ± 2.8 in KO, p = 0.007; and 7.7 ± 6.7 in WT vs. 17.7 ± 12.2 in KO, p = 0.03, respectively). Although CP number was not significantly different between the two groups (13.4 ± 5.3 in WT vs. 16.3 ± 7.5 in KO, p = 0.32), their size and shapes were altered in KO mice. Notably, findings occurred in the setting of significant lymphopenia. α-Synuclein deficiency leads to changes in size and shape of secretory particles and increases in SER, SG, and inclusions, indicating a potential role for α-synuclein in vesicular trafficking in leukocytes. Further studies are needed to elucidate functions mediated by α-synuclein.