Fig. 4: Aplnra is required for ventral-dorsal migration of EC in venous ISV. | Nature Communications

Fig. 4: Aplnra is required for ventral-dorsal migration of EC in venous ISV.

From: Parenchymal cues define Vegfa-driven venous angiogenesis by activating a sprouting competent venous endothelial subtype

Fig. 4

a, b Confocal images showing endothelial cell movements in flt1−/− (a) and flt1−/−; aplnra−/− double mutant (b) at indicated time points. Arrowheads indicate EC nuclei and migration trajectory in the vISV. c Quantification of endothelial migration distance in vISV for indicated scenario. Mean±s.e.m.; two-sided unpaired t test with Welch’s correction, flt1−/−: n = 70 ECs (2–3 per vISVs), flt1−/−; aplnra−/−: n = 32 ECs (2–3 per vISV); p = 0.0030. d Traces of individual endothelial cell movements in flt1−/− (top) and flt1−/−; aplnra−/− double mutant (bottom). flt1−/−: n = 70 ECs, flt1−/−; aplnra−/−: n = 32 ECs. e Confocal images showing EC distribution in vISVs of flt1−/− mutant (left) and flt1−/− upon loss of aplnra (right) at 3 dpf. Asterisks mark ECs in the dorsal (red) and ventral (yellow) domain. f Quantification of dorsoventral distribution of ECs for indicated scenario. Mean±s.e.m.; two-sided Fischer’s exact test; flt1−/−: n = 123 ECs from 13 vISVs, flt1−/−+aplnra MO: n = 108 ECs from 12 vISVs; p = 0.0223. g Confocal images of Tg(−0.8flt1:RFP;flt4:mCitrine) to visualize ECs with arterial (red arrowhead) or venous (green arrowhead) identity in vISVs for flt1−/− (left) and flt1−/−; aplnra−/− double mutant (right) at 3 dpf. h Percentage ECs with arterial identity in the dorsal domain of vISVs. Mean; two-sided Mann–Whitney U test; flt1−/−: n = 32 vISVs from 16 embryos; flt1−/−; aplnra−/−: n = 66 vISVs from 33 embryos; p = 0.0148. i Confocal images of Tg(fli1:nEGFP;fli1:B4GALT1galT-mCherry) showing EC nuclei (green), and position of golgi (red) regarding blood flow direction (red arrow) indicated as angle α. For α = 150-180, polarized against flow-direction; for α = 0–30, polarized in flow-direction. j Confocal images of Tg(fli1:nEGFP;fli1:B4GALT1galT-mCherry) and diagrams showing polarization status of individual ECs in vISV for flt1−/− mutant (left) and flt1−/− upon loss of aplnra (right). k EC polarization for indicated scenario. Mean; Chi-square test, flt1−/−: n = 165 vECs from 21 embryos, flt1−/− + aplnra MO: n = 196 vECs from 19 embryos, p < 0.0001. Scale bars indicate 20 μm in a, b, e, g, j. DA dorsal aorta, PCV posterior cardinal vein, DLAV dorsal lateral anastomotic vessel, MO morpholino, vISV venous intersegmental vessel. Source data are provided as a Source Data file.

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