Carbohydrate-binding protein CLEC14A regulates VEGFR-2– and VEGFR-3–dependent signals during angiogenesis and lymphangiogenesis
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
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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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 6

VEGFR-2 inhibitors suppress tumor growth, increase the number of functional vessels, and improve the survival of tumor-bearing CLEC14A-KO mice.

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VEGFR-2 inhibitors suppress tumor growth, increase the number of functio...
(A) Growth curves of B16F10-derived tumors treated with vehicle (DMSO), sunitinib, or DMH4. n = 6 per group. (B) Size of captured B16F10 tumors under the different treatment conditions. (C) Survival curves of B16F10-injected WT and CLEC14A-KO mice treated with vehicle, sunitinib, or DMH4. n = 6 per group. (D) Images of B16F10 tumor masses before capture from WT and CLEC14A-KO mice treated with DMSO, sunitinib, or DMH4. (E) Immunostaining for CD31 and lectin as well as FITC-dextran and DAPI staining showing reduced leakage and increased numbers of functional vessels in mice treated with sunitinib or DMH4 compared with those treated with vehicle. Scale bars: 100 μm. (F and G) Quantification of functional vessels and FITC-dextran leakage in tumors from WT and CLEC14A-KO mice treated with DMSO, sunitinib, or DMH4. n = 6 per group. *P < 0.05, **P < 0.005, and ***P < 0.0001, by paired, 2-tailed Student’s t test. Error bars represent the mean ± SD.