APP and Alzheimer disease: Overexpression of MKP-1 by AAVMKP-1 in the brains of AD mice decreased the expression of APP (AAVEGFP: 221.22 ± 57.47% vs. AAVMKP-1: 117.09 ± 23.97%, p = 0.037), C89 (AAVEGFP: 169.42 ± 29.51% vs. AAVMKP-1: 106.44 ± 15.11%, p = 0.039), C99 (AAVEGFP: 195.15 ± 35.38% vs, AAVMKP-1: 121.52 ± 33.51%, p = 0.016), and BACE1 (AAVEGFP: 156.70 ± 13.56% vs. AAVMKP-1: 105.18 ± 17.36%, p = 0.005) (Fig. 5h–l).