Figure 1: Biochemical characterization of NPC (Niemann-Pick disease type C) pathology from human brain tissue.

(A) Immunohistochemistry was conducted on sections of mid-frontal cortex of case 4237 (see Supplementary Table 1). Hematoxylin and eosin staining shows numerous ballooned neurons, magnification 200x. Thioflavin-S staining shows thioflavin-S positive tangles, magnification 400x. Tau pathology including dystrophic neurites was detected using anti-tau antibodies ET3 and RD3 as well as phospho-tau antibody AT8, magnification 200x. Arrows indicate histopathological abnormalities. (B) Representative Western blot showing Triton-soluble total tau in cortical brain tissue lysates from NPC patients (n = 3) and controls (n = 3). Statistical analysis represent n = 5 controls and n = 8 NPC patients. (C) Representative Western blots showing formic acid-soluble total tau (red) in cortical brain tissue lysates from controls (n = 5) and NPC patients (n = 8) (left: 3 controls, 4 NPC patients; right: 2 controls, 4 NPC patients) and corresponding phospho-tau (green). Arrows point to the most severe patients, 4237 (left) and M40002M (right). Asterisks mark the youngest patients, 4770 (left) and M4004M (right) (compare Supplementary Table S1). Equal volumes/tissue wet weight of each sample were loaded. Statistical analysis represent n = 5 controls and n = 8 NPC patients. (D) Representative Western blot showing Triton-soluble amyloid precursor protein (APP) in lysates of cerebellar tissue. APP-full length (APP-FL) protein and C-terminal fragments of APP (APP-CTF) protein are indicated. Statistical analysis represent n = 5 controls and n = 6 NPC patients. (E) Aβ42 and Aβ40 levels were quantified using enzyme-linked immunosorbent assay (ELISA) in Triton-soluble fractions from control (n=3) and NPC (n=5) cortical samples, and the Aβ42/40 ratio was determined. Error bars, mean ± standard error of the mean. *P < 0.05, Student's t test; n.s., not significant.