We found that 5-day treatment of oligomerized amyloid beta (Aβ 1 μM; abcam), which has been known to induce AD-like astrocyte reactivity in vitro [27] upregulated the expression of candidate enzymes Putrescine Acetyltransferase (Sat1), SIRT2 (Sirt2) and ALDH1A1 (Aldh1a1) involved in the putrescine-to-GABA degradation pathway (Fig. 1E) in hippocampal astrocytes. The gene discussed is ALDH1A1; the disease is Alzheimer disease.