DCN and Alzheimer disease: Similarly, astrocyte-produced IGFBP6, which inhibits neuronal differentiation in vitro (Barkho et al., 2006), is elevated in the serum of AD patients (Tham et al., 1993); and decorin, which also decreases neuronal differentiation of aNSC/progenitor cells in vitro (Barkho et al., 2006), is increased in AD mice model (Lam et al., 2011).