Figure 2.
Osteoprogenitor association with type H ECs.
a. Confocal images of 4 week-old tibia with indicated stainings. Growth plate (gp) and bone marrow cavity (bm) are marked. Osterix+ cells are found around CD31hi/Emcnhi vessels in metaphysis and endosteum (arrowheads)
b, Collagen1α+ cells (green) surround columnar CD31+ vessels (red) but not CD31-Emcn+ type L bone marrow (bm) sinusoids in 3 week-old mouse tibia.
c, Immunostained 4 week-old tibia showing association of Runx2+ osteoprogenitors (green) with CD31+ (red) vessels in metaphysis and endosteum (es). Minimum exposure was used to capture only cells with high CD31 fluorescence in (a-c).
d, Quantitative analysis of proximity (≤20μm) of Runx2+, Collagen1α+ (Col1α) and Osterix+ (Osx) to nearest type H vessel. Mean±s.e.m, n=5 mice from three independent experiments.
e, Maximum intensity projection of PDGFRβ+ cells (green) next to CD31+ (red) metaphyseal columns and distal arches (asterisks), and close to endosteal (es) type H ECs. PDGFRβ also marked arteries and rare cells (arrowheads) associated with Emcn+ type L bone marrow (bm) sinusoids (right).