Figure 1. Osteolectin is expressed by peri-arteriolar LepR⁺ cells.

Images are representative of 3–5 experiments with 8–10-week-old mice. (a-c) Flow cytometric analysis of enzymatically dissociated bone marrow from Oln^mT/+ mice (4 mice per genotype in 4 independent experiments). (b) Most Oln-Tomato⁺ cells were LepR⁺. (c) Only a small minority of LepR⁺ cells were Oln-Tomato⁺. (d and e) Representative femur sections showing the epiphysis (d) and diaphysis (e) from 2–4-month-old Oln^mT/+; Col1a1*2.3-EGFP mice. Panel d shows Oln-Tomato⁺ hypertrophic chondrocytes (arrow) and Oln-Tomato⁺Col1a1*2.3-EGFP⁺ osteoblasts in trabecular bone (arrowhead; scale bar = 30μm). Panel e shows Oln-Tomato⁺Col1a1*2.3-EGFP⁺ osteoblasts in the endosteum (arrow) and Oln-Tomato⁺ osteocytes (arrowhead; scale bars = 25μm). (f and g) Deep imaging of Oln^mT/+ femur bone marrow. The boxed area in panel f is magnified in panel g. Panel f shows peri-arteriolar Oln-Tomato⁺ cells (arrowhead) as well as Oln-Tomato⁺ cells on the endosteal surface (arrow; scale bar = 100μm). Panel g shows Oln-Tomato⁺LepR⁺ peri-arteriolar stromal cells (arrowhead) and Oln-Tomato⁻LepR⁺ peri-sinusoidal stromal cells (arrow; scale bar = 40μm). (h) Oln-Tomato⁺ cells around Sca-1⁺ arterioles (arrow) but not Endomucin^high sinusoids (scale bar = 200μm). All data represent mean ± SD.