BACE1 and Alzheimer disease: Since both accumulation and complete elimination of BACE1/Aβ adversely affect recovery after SCI, biological regulation of Aβ or BACE1 levels after SCI by modulation of components of the UPS such as Fbx2-Uch-L1 via peroxisome proliferator-activated receptor-gamma co-activator (PGC)-1alpha or gene expression (Gong et al., 2010, 2013b) may be a feasible strategy for the SCI treatment and AD (Figure 3).