TGFB1 and Cognitive impairment: TGF-β is an immunosuppressive cytokine that protects neurons against damage. A genetic polymorphism in in TGFB1 is associated with the risk of developing AD (Luedecking et al., 2000). Post mortem AD brains contain increased levels, specifically in Aβ plaques (van der Wal et al., 1993; Chao et al., 1994). Long-term overexpression of TGF-β by astrocytes can increase Aβ clearance by microglia and improve cognitive impairment (Wyss-Coray et al., 2001; Chen et al., 2015). Conversely, TGF-β induces astrocyte aggregation and Aβ deposition near brain microvessels (Ueberham et al., 2005).