RUNX2 and osteoporosis: NM improved proliferation, ALP activity, mineralization, and expression of osteoblast differentiation markers (BMP-2, p-SMAD 1/5/8, RUNX2, Wnt3a, osteocalcin, and COL-1) in an osteoblastic cell line in vitro and in a model of osteoporosis in vivo.