Fig. 1

Levels of TBS-Soluble ACE2 protein are higher in AD individuals and are negatively correlated with global cognitive score. Parietal cortex levels of ACE2 protein from Cohort #1 were determined by Western blotting after SDS-PAGE (10% acrylamide) of three fractions: a TBS-soluble fraction A–D a detergent-soluble fraction E–H and a microvessel-enriched fraction L–O. No statistical difference was detected for ACE2 in the three fractions when subjects were classified according to antemortem clinical diagnosis (B, F, M). However, the TBS/Detergent-Soluble ACE2 ratio was higher in clinical AD subjects I. Levels of the ACE2 protein were higher in the TBS-soluble fraction and in the ratio TBS/Detergent-Soluble in individuals with a neuropathological diagnosis of AD based on ABC scoring C, G, J, N. TBS-soluble ACE2 and microvascular ACE2 levels were negatively correlated with the global cognitive score D, O. An equal amount (12 µg) of proteins per sample for both TBS-soluble and detergent soluble fractions was loaded and 8 µg of proteins per sample was loaded for microvessel-enriched fractions. All samples, loaded in a random order, were run on the same gel and transferred on the same membrane before immunoblotting for quantification. Examples were taken from the same experiment, and consecutive bands loaded in random order are shown. Actin and cyclophilin B are shown as loading controls. Data are represented as a scatterplot. A very high outlier has been removed in the clinical AD group in I, J and K. Horizontal lines indicate mean ± SEM. Statistical analysis: Two groups: Mann–Whitney test **p < 0.01; Three groups: Kruskal–Wallis followed by a Dunn’s multiple comparisons *p < 0.05, Coefficient of determination & p < 0.05. ACE2 Angiotensin-Converting Enzyme 2, A or AD Alzheimer’s disease, C Control, Clin Dx Clinical diagnosis, ABC Dx ABC neuropathological diagnosis, CyB Cyclophilin B, M or MCI Mild cognitive impairment, N or NCI Healthy controls with no cognitive impairment, O.D. optical density, SEM Standard error of the mean, TBS Tris-Buffered Saline