Fig. 1: CNS vascularization is compromised after FLRT2 deletion in ECs.
From: Vascular FLRT2 regulates venous-mediated angiogenic expansion and CNS barriergenesis
a Flrt2 mRNA detection by fluorescence in situ hybridization (FISH) in P8 wild-type mouse retina in the optic nerve head (ONH) area, where the central artery and vein enter the retina, and in the superficial vascular plexus (SVP) (upper panel); and in P8 wild-type cerebral cortex (upper cortical layers and pial vasculature) (lower panel). Blood vessels were detected by immunostaining with podocalyxin (Podxl) (general vessel marker). b Coronal section of the cerebral cortex from P6 wild-type mouse stained for FLRT2 and NeuN as neuronal marker (neuronal layers I-VI annotated). Blood vessels were visualized with isolectin-B4 (IB4) staining. Arrows show FLRT2 positive blood vessels (right). c Flat-mounted P7-P8 retinas from control and Flrt2iΔEC littermate mice injected with 4-hydroxytamoxifen (Tmx) from P1 to P3 and stained with IB4. Quantification of radial vascular length ratio (d), total retinal vessel length (e), and total number of branch points (f) per retina. n = 12 control and 7 mutant (d), 7 control and 6 mutant (e, f) animals. Two-tailed unpaired t-test, p = 0.0004 (d), 0.013 (e), 0.005 (f). g Representative images of P7-P8 control and Flrt2iΔEC flat-mounted retinas stained for IB4. Veins (V) and arteries (A) are indicated. h Quantification of capillary network density between veins and arteries. n = 8 animals per genotype. Two-tailed unpaired t-test, p = 0.0005. i Glut1 staining of the vasculature in control and Flrt2iΔEC brain cortices from P7-P8 mice after Tmx administration from P1 to P3. Quantification of vessel density (j), vessel length (k) and number of branch points (l). n = 7 animals per genotype. Two-tailed unpaired t-test, p = 0.028 (j), 0.001 (k), 0.001 (l). Scale bars: 20 μm (a), 50 μm (b), 500 μm (c), 200 μm (g), 100 μm (i). Data are shown as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001.
