Given that we previously demonstrated expression of GDF5 and GDF6 by human NP cells [16] and that both AD-MSCs and BM-MSCs can differentiate to NP-like cells [6], here we aimed to investigate whether GDF6 may be a more-appropriate stimulus for MSC discogenic differentiation and production of an NP-like ECM than either TGF-β or GDF5. Here, TGFB1 is linked to Alzheimer disease.