Fig. 3: Properties and origin of type R capillaries.
From: Specialized post-arterial capillaries facilitate adult bone remodelling
a, Perfusion of EMCN+VEGFR3− type R capillaries (arrowheads) near TB demonstrated by injected 2,000 kDa TRITC dextran (yellow) in 12-week-old wild-type femur. b, Representative confocal images of 12-week-old Efnb2-H2B-GFP (green) femur section co-stained for EMCN (red) and VEGFR3 (blue). Efnb2+EMCN+ rECs (white arrowheads) are connected to Efnb2+EMCN− arterioles and arteries (green arrowheads). c,d, Type III collagen (COL3A1) (c) and type IV collagen (COL4A1) (d) are tightly associated with EMCN+VEGFR3− type R capillaries (arrowheads) in 12-week-old wild-type femur, whereas the surrounding sinusoidal vessels show a loose reticular fibre network. e, High-magnification images showing filopodia (arrowheads) extending from EMCN+VEGFR3− rECs around 12-week-old TB. f, Proliferating rECs (white arrowheads) near 6-week-old TB. Cdh5-mTnG reporter (nGFP, red) shows EC nuclei co-stained with KI-67 (green). g, Scheme of genetic fate-mapping strategy. 4-OHT administration (1 mg per mouse) is indicated by black arrow and red arrows mark time points of analysis. h,i, Tile-scan confocal images (h) and higher magnification of insets (i) showing fate-tracked Flt4-CreERT2 R26-mTmG (GFP, green)-labelled ECs in femur at 8 weeks (48 h after Cre induction) and 12 weeks (4 weeks after Cre induction). White arrowheads indicate EMCN+CAV1+ rECs and yellow arrowheads mark GFP+ traced rECs. j, Quantitative analysis of GFP+ rECs (EMCN+CAV1+FLT4-GFP+) at 48 h and 4 weeks post-induction, respectively. n = 3 mice per group. Mean ± s.e.m. P values were obtained using an unpaired two-tailed t-test. k, Schematic illustration of genetic fate mapping of rECs in Flt4-CreERT2 R26-mTmG femur.
