Extended Data Fig. 6: Apelin maintains crypt venous capillary patency at steady state and during crypt expansion.
From: Apelin-driven endothelial cell migration sustains intestinal progenitor cells and tumor growth
(a-b) Neither vessel density nor blood endothelial cell (BEC) proliferation are decreased in Apln-/- mice. (a) Quantification of crypt vessel density in control and Apln-/- mice (p = 0.0368, n = 3 WT mice and n = 4 Apln-/- mice). (b) Quantification of percentage of villus and crypt Ki67+ BECs in control and Apln-/- mice (n = 8 WT mice and n = 6 Apln-/- mice). (c) Quantification of the number of empty collagen sleeves / villus area of wild-type and Apln-/- mice (n = 4 WT mice and n = 3 Apln-/- mice). (d) Venous identity of regressing crypt vessels in Apln-/- mice. Whole-mount immunostaining for VEGFR2 (green), venous marker endomucin (red) and collagen IV (white). Arrowheads, empty collagen sleeves between endomucin+ vessels; arrow, regressing vessel. Quantification of number of regressed crypt vessels in Apln-/- mice sorted by endomucin status of each end of regressed vessel (n = 3 mice). (e) Quantification of crypt vessel density in ApcΔIEC and ApcΔIEC; Apln-/- mice (n = 3 ApcΔIEC and n = 4 ApcΔIEC; Apln-/- mice). (f) Quantification of percentage of villus and crypt Ki67+ BECs in ApcΔIEC and ApcΔIEC; Apln-/- mice (n = 4 mice). (g) Increased number of blind-ended crypt blood vessels in ApcΔIEC; Apln-/- mice. Whole-mount immunostaining of intestinal vessels (red, VEGFR2) from ApcΔIEC and ApcΔIEC; Apln-/- mice. Insets: blind-ended crypt vessels (arrowheads). (h) Increased empty collagen sleeves (green, collagen IV) in crypt vessels (red, VEGFR2) of ApcΔIEC; Apln-/- compared to ApcΔIEC mice. Quantification of number of empty collagen sleeves per crypt vessel length (p = 0.0002, n = 5 ApcΔIEC and n = 4 ApcΔIEC; Apln-/- mice). (i) Venous identity of regressing crypt vessels in ApcΔIEC; Apln-/- mice. Whole-mount immunostaining of crypt vessels (green, VEGFR2) and venous identity marker endomucin (red) from ApcΔIEC and ApcΔIEC; Apln-/- mice. Quantification of number of regressed crypt vessels in ApcΔIEC; Apln-/- mice sorted by endomucin status of each end of regressed vessel (n = 4 mice). Scale bars: 50 μm: g-i; 20 μm: d, g + h (insets). All data are shown as mean ± SD. *P < 0.05, ***P < 0.001, 2-tailed unpaired Student’s t-test.
