TGFB1 and Alzheimer disease: The regulatory role of TGF-β1 in AD pathogenesis, therefore, has been intensively examined by over-expressing TGF-β1 or blocking the TGF-β-SMAD signaling pathway [14,18,19] Wyss-Coray et al. showed that overexpression of TGF-β1 prominently reduces plaque formation and Aβ accumulation in hAPP mice [19].