Based on many results regarding aging-related pathology (Figure 2), the effects of TGF-β signaling can be generalized into two aspects: (1) The impairment of TGF-β signaling in certain cell types, exemplified by a loss of neuroprotective activities in AD and a loss of TGF-β-mediated growth inhibition in cancer, and (2) the chronic elevation of TGF-β signaling linked to tissue fibrosis, chronic inflammation, and decreased regeneration capacity, as well as metabolic malfunction observed in AD, muscle atrophy, obesity, and other diseases. Here, TGFB1 is linked to Atrophy.