Figure 6: GBA1 deficiency leads to an increase in cell-to-cell transmission of α-synuclein aggregates.

Scale bars, 20 μm. (a) Cell-to-cell α-synuclein transmission in the dual-cell BiFC system. BiFC-positive aggregates are indicated by arrowheads; n=4, 500 cells per experiment, *P<0.05 by paired, two-tailed Student’s t-test. (b) Accumulation of ectopically introduced α-synuclein aggregates (sonicated fibrils). Fluorescence was measured in 500 cells in each of the four independent experiments. *P<0.05 by paired, two-tailed Student’s t-test. (c) Subcultures of the dual-cell BiFC system. (d) Quantification of BiFC-positive cells shown in c. n=3, 500 cells per each experiment, *P<0.05, ***P<0.005, ****P<0.0001 by paired, two-tailed Student’s t-test. (e) Multimeric α-synuclein ELISA analysis of culture media from the indicated subcultures. n=3, *P<0.05, ***P<0.005 by paired, two-tailed Student’s t-test. (f,g) Reversal of the GBA1 knockout phenotype by expression of wild-type GBA1, but not the activity-deficient E235K GBA1 mutant; n=4, 1,000 cells per each experiment, *P<0.05, #P<0.05 by paired, two-tailed Student’s t-test.