APP and Alzheimer disease: In this study, we examined the AHN levels in four animal models of neurological diseases: the amyloid precursor protein (APP) and presenilin 1 (PS1) transgenic mice for Alzheimer’s disease, neuroinflammation induced by intracerebroventricular (i.c.v.)injection of lipopolysaccharide (LPS), learned helplessness (LH) and chronic restraint stress (CRS) to mimic stress and MDD (Supplementary Fig. 1).