Carbohydrate-binding protein CLEC14A regulates VEGFR-2– and VEGFR-3–dependent signals during angiogenesis and lymphangiogenesis
Sungwoon Lee, … , Young-Myeong Kim, Young-Guen Kwon
Sungwoon Lee, … , Young-Myeong Kim, Young-Guen Kwon
Published December 19, 2016
Citation Information: J Clin Invest. 2017;127(2):457-471. https://doi.org/10.1172/JCI85145.
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Research Article Angiogenesis Vascular biology

Carbohydrate-binding protein CLEC14A regulates VEGFR-2– and VEGFR-3–dependent signals during angiogenesis and lymphangiogenesis

Abstract

Controlled angiogenesis and lymphangiogenesis are essential for tissue development, function, and repair. However, aberrant neovascularization is an essential pathogenic mechanism in many human diseases, including diseases involving tumor growth and survival. Here, we have demonstrated that mice deficient in C-type lectin family 14 member A (CLEC14A) display enhanced angiogenic sprouting and hemorrhage as well as enlarged jugular lymph sacs and lymphatic vessels. CLEC14A formed a complex with VEGFR-3 in endothelial cells (ECs), and CLEC14A KO resulted in a marked reduction in VEGFR-3 that was concomitant with increases in VEGFR-2 expression and downstream signaling. Implanted tumor growth was profoundly reduced in CLEC14A-KO mice compared with that seen in WT littermates, but tumor-bearing CLEC14A-KO mice died sooner. Tumors in CLEC14A-KO mice had increased numbers of nonfunctional blood vessels and severe hemorrhaging. Blockade of VEGFR-2 signaling suppressed these vascular abnormalities and enhanced the survival of tumor-bearing CLEC14A-KO mice. We conclude that CLEC14A acts in vascular homeostasis by fine-tuning VEGFR-2 and VEGFR-3 signaling in ECs, suggesting its relevance in the pathogenesis of angiogenesis-related human disorders.

Authors

Sungwoon Lee, Seung-Sik Rho, Hyojin Park, Jeong Ae Park, Jihye Kim, In-Kyu Lee, Gou Young Koh, Naoki Mochizuki, Young-Myeong Kim, Young-Guen Kwon

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Figure 2

Deletion of Clec14a results in increased development of poorly functional (hemorrhage-prone) vessels.

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Deletion of Clec14a results in increased development of poorly functiona...
(A) Murine aortic ring assay for P7 WT and CLEC14A-KO mice (VEGF-A; 50 ng). n = 3 per group. Magnification ×10. (B–D) Quantification of the number of sprouts, filopodial length, and relative sprouting area (percentage of control). (E) Matrigel plugs implanted into 7-week-old WT and CLEC14A-KO mice for 5 or 10 days. n = 6 per group. (F) Quantification of Hb (mg/ml) extracted from Matrigel plugs from WT and CLEC14A-KO mice. n = 6 per group. (G) CD31 immunostaining of Matrigel plugs implanted into WT and CLEC14A-KO mice for 10 days. Scale bars: 100 μm. (H) Quantification of the relative CD31-positive area (percentage of control). (I) Hemorrhage in P17 WT and CLEC14A-KO mouse retinae after hyperoxia (OIR model). n = 3 per group. (J) Whole-mount isolectin B (green) staining of P17 retinae from WT and CLEC14A-KO mice. Scale bars: 500 μm. (K and L) Relative avascular and neovascularization areas in P17 retinae from WT and CLEC14A-KO mice (percentage of control). All experiments were repeated on at least 3 different sets of WT and KO littermates. *P < 0.05, **P < 0.005, and ***P < 0.0001, by paired, 2-tailed Student’s t test. Error bars represent the mean ± SD.