Fig. 5.
Constitutive mTORC1 activation in myeloid lineage impedes osteoclast differentiation. Analyses of Tsc1fl/fl-Lyz-Cre cKO mice and littermate controls. a, b Expression of osteoclast markers (a) and osteoclastogenic transcription factors (b) in bone marrow osteoclast differentiation cultures (n = 6). c Representative images of TRAP-stained osteoclast differentiation cultures. d Osteoclast resorptive activity measured by calcium release from bone plates (n = 16). e Osteoclast precursor proliferation by BrdU incorporation (n = 10). f, g mTORC1 signaling in bone marrow osteoclast differentiation cultures 60 h after RANKL treatment. f Phosphorylation of mTOR; g Phosphorylation of S6K1. p/T ratio of phosphorylated/total protein. h–r Bone phenotype in 2-month-old male mice. h Serum CTX-1 bone resorption marker (n = 8). i Serum P1NP bone formation marker (n = 8). j Bone histomorphometry of distal femurs (n = 6). Oc.S osteoclast surface, B.S bone surface, Oc.N osteoclast number. k Bone histomorphometry of distal femurs (n = 6). Ob.S osteoblast surface, B.S bone surface, Ob.N osteoblast number. l Representative μCT images of the trabecular bone of the tibial metaphysis (top) and the entire proximal tibia (bottom). m–r Quantification of trabecular bone volume and architecture in proximal tibiae by μCT (n = 8). m BV/TV bone volume/tissue volume ratio, n BS bone surface, o Tb.N trabecular number, p Tb.Sp trabecular separation, q Conn. D. connectivity density, r SMI structure model index. Error bars, SEM; *p < 0.05; **p < 0.01; ***p < 0.005; ****p < 0.001; n.s. non-significant. T Tsc1. Full-size scans of immunoblots are shown in Supplementary Fig. 9