Fig 1.
X-ray microCT imaging of the proximal tibia from 7 days old mice.
(A, D) Representative sagittal sections of the proximal tibia showing the trabecular and cortical bone architecture. (B, E) Segmented view of the trabecular bone at proximal metaphysis obtained from 7-day old mice (WT, top and OIM, bottom). (C, F) Representative microCT image of the cortical bone at mid-diaphysis.
Fig 2.
X-ray microCT imaging of the proximal tibia from 8 weeks-old mice.
(A, D) Representative sagittal sections of the proximal tibia showing the trabecular and cortical bone architecture. (B, E) Segmented view of the trabecular bone obtained from 8-week-old mice (WT, top OIM, bottom). (C, F) Representative microCT image of the cortical bone at mid-diaphysis.
Fig 3.
MicroCT morphometric analysis.
(A) Quantification of morphometric parameters of tibial trabecular bone in 1 week-old and in 8 week-old WT and OIM mice. Cortical volume (mm3), medullary volume (mm3), cortical thickness (mm), total porosity (%), medullary canal thickness (mm), tissue mineral density (TMD, g/cm2). (B) Quantification of morphometric parameters of tibial cortical bone. Bone volume percent (BV/TV, %), bone surface density (BS/TV, 1/mm), trabecular number (1/mm), trabecular thickness (mm), Intersection surface (mm2), trabecular pattern factor (1/mm). All microCT parameters were analysed using Bonferroni’s multiple comparison post hoc test., ***P < 0.001, **P < 0.01 and * P < 0.05. ns: not significant. n = 7 for all the groups.
Fig 4.
In vitro assessment of the mineral deposition in WT and OIM osteoblasts.
(A) Phase contrast of primary calvaria osteoblasts. (B) Phase contrast of osteoblasts cultured in basal and osteogenic conditions at day 0, 21, and 30. (C) Alizarin Red staining. (D) Measurement of the mineralization area.
Fig 5.
RNAseq analysis of mature WT osteoblasts vs WT pre-osteoblasts (WT d21 vs WT d0) and mature OIM osteoblasts vs OIM pre-osteoblasts (OIM d21 vs OIM d0) during osteogenic differentiation (A) Volcano plots showing significant (FDR adjusted p<0.05) DEGs (differentially expressed genes) in (WT d21 vs WT d0) and(OIM d21 vs OIM d0) (B) after 3 weeks in osteogenic induction medium. DEGs were plotted by pathways: osteogenesis (C, D), cell stress response (E, F), TGF-Beta pathway (G, H), autophagy (I, J).
Fig 6.
RNAseq analysis of mature WT vs mature OIM osteoblasts (OIM d21 vs WT d21) and WT pre-osteoblasts vs OIM pre osteoblasts (OIM d0 vs WT d0).
(A) Volcano plots showing significant (FDR adjusted p<0.05) DEGs (differentially expressed genes) in OIM d21 vs WT d21 (B) OIM d0 vs WT d0. DEGs were plotted by pathways: TGF-β signalling (C), cell stress (D), osteogenesis (E), autophagy (F).
Fig 7.
Simplified model of the various pathways contributing to bone fragility in homozygous OIM mice.
Created by Biorender.