Fig 1: Apolipoprotein J (APOJ) ELISA.APOJ protein levels were measured in three distinct healthy lines of iAstrocytes’ conditioned medium. (A) Regression analysis with the Four-parameter logistic curve-fit (4-PL) method was used to determine the best-fit standard curve based on twofold serial dilutions of APOJ standards and absorbance at 450 nm. (B) iAstrocytes were either left untreated or treated for 24 h with various recombinant DPRs at 1 µM (poly-GA34 fibrils, poly-GA34 oligomers, poly-PA50 oligomers, and poly-GP24 oligomers), and then APOJ protein levels in their conditioned medium were measured and calculated using the previously generated 4-PL standard curve. Bar graphs of mean ± SEM. One-way ANOVA with Tukey’s multiple-comparisons test (control group is “untreated”). *P = 0.05, **P = 0.01, ***P = 0.001, and ****P = 0.0001.