GPR126 is a specifier of blood-brain barrier formation in the mouse central nervous system
Nikolaos Kakogiannos, … , Donato Inverso, Monica Giannotta
Nikolaos Kakogiannos, … , Donato Inverso, Monica Giannotta
Published August 1, 2024
Citation Information: J Clin Invest. 2024;134(15):e165368. https://doi.org/10.1172/JCI165368.
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Research Article Angiogenesis Vascular biology

GPR126 is a specifier of blood-brain barrier formation in the mouse central nervous system

Abstract

The blood-brain barrier (BBB) acquires unique properties to regulate neuronal function during development. The formation of the BBB, which occurs in tandem with angiogenesis, is directed by the Wnt/β-catenin signaling pathway. Yet the exact molecular interplay remains elusive. Our study reveals the G protein–coupled receptor GPR126 as a critical target of canonical Wnt signaling, essential for the development of the BBB’s distinctive vascular characteristics and its functional integrity. Endothelial cell–specific deletion of the Gpr126 gene in mice induced aberrant vascular morphogenesis, resulting in disrupted BBB organization. Simultaneously, heightened transcytosis in vitro compromised barrier integrity, resulting in enhanced vascular permeability. Mechanistically, GPR126 enhanced endothelial cell migration, pivotal for angiogenesis, acting through an interaction between LRP1 and β1 integrin, thereby balancing the levels of β1 integrin activation and recycling. Overall, we identified GPR126 as a specifier of an organotypic vascular structure, which sustained angiogenesis and guaranteed the acquisition of the BBB properties during development.

Authors

Nikolaos Kakogiannos, Anna Agata Scalise, Emanuele Martini, Claudio Maderna, Andrea Francesco Benvenuto, Michele D’Antonio, Laura Carmignani, Serena Magni, Giorgia Serena Gullotta, Maria Grazia Lampugnani, Fabio Iannelli, Galina V. Beznoussenko, Alexander A. Mironov, Camilla Cerutti, Katie Bentley, Andrew Philippides, Federica Zanardi, Marco Bacigaluppi, Sara Sigismund, Claudia Bassani, Cinthia Farina, Gianvito Martino, Marco De Giovanni, Elisabetta Dejana, Matteo Iannacone, Donato Inverso, Monica Giannotta

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Figure 4

GPR126 is required for angiogenesis in the retina and in the brain.

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GPR126 is required for angiogenesis in the retina and in the brain. (A) ...
(A) Confocal images of CD93 (magenta, ECs), ERG (green, EC nuclei), and EdU (red, proliferation) in WT and Gpr126iECKO mouse retinas at P6 show retinal vessels at the petal, front, and rear regions. White dots highlight tip cells. Scale bars: petal, 500 μm; rear, 100 μm; front, 250 μm. (B) Tip cell quantification in the yellow rectangle in A (n = 3 WT, n = 3 Gpr126iECKO retinas). (C) Retinal vasculature radial expansion at P6, P10, P14, and P18 in WT and Gpr126iECKO mice (n = 6–8 WT, n = 6–7 Gpr126iECKO retinas). (D) Postnatal retinal vessel density (P6, P10, P14, P18) in WT and Gpr126iECKO mice (n = 5–10 WT, n = 6–9 Gpr126iECKO retinas). (E) EdU-positive ECs/μm2 of vessel area postnatally (P6, P10, P14, P14) in WT and Gpr126iECKO retinas (n = 5 WT, n = 5 Gpr126iECKO retinas). (F) Phase-contrast images of sprouting spheroids from fBECs of WT and Gpr126iECKO mice at P18 after stimulation with VEGF (80 ng/mL) and FGFb (50 ng/mL). Right: Magnified images at t = 40, 44, and 48 hours (for time-lapse, see Supplemental Video 1). Arrows, sprouting ECs; arrowheads, retracting ECs. Scale bars: 40 μm. (G) Cumulative sprouts per spheroid of WT (n = 16) and Gpr126iECKO (n = 16) fBECs. Each symbol represents an experiment (n = 4 WT, n = 4 Gpr126iECKO mice). (H) Cumulative sprouting lengths per spheroid of WT (n = 12) and Gpr126iECKO (n = 12) fBECs after 12, 24, 36, and 48 hours (n = 6 WT, n = 6 Gpr126iECKO mice). (I) Aortic rings from WT and Gpr126iECKO mice show vascular sprouts (magnified) via IB4 immunostaining. Scale bars: 500 μm. (J and K) Endothelial sprouting area (J) and branch numbers (K) as depicted in I (n = 6 WT, n = 6 Gpr126iECKO mice). Data are shown as means ± SD. (B–D, G, J, and K) Unpaired t tests with Welch’s correction; (E and H) 2-way ANOVA. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.