Likewise, Nrf2 over-expression in astrocytes can protect neurons in a non-cell autonomous manner from 3-NP toxicity, while Sirt1 over-expression can delay axonal degeneration and counteract neurodegeneration in a mouse model of Alzheimer disease [40], [41], [43], [44]. The gene discussed is SIRT1; the disease is early-onset autosomal dominant Alzheimer disease.