Fig 1: The effects of the novel small molecule compounds on the USP13 activities and alpha-synuclein in vitro. The SH-SY5Y cells were transinfected with human alpha-synuclein plasmid. Cells were treated with a serial of concentrations of each individual compound for 5 h. ELISA was performed for (A–F) USP13, and (G) estimated IC50 to USP13 was calculated. ELISA for (H–M) alpha-synuclein. ** p < 0.01, **** p < 0.0001 to DMSO group, ## p < 0.01, #### p < 0.0001 to untreated group; ordinary one-way ANOVA. N = 3–9 per treatment group.