Epsin deficiency promotes lymphangiogenesis through regulation of VEGFR3 degradation in diabetes
Hao Wu, … , R. Sathish Srinivasan, Hong Chen
Hao Wu, … , R. Sathish Srinivasan, Hong Chen
Published August 13, 2018
Citation Information: J Clin Invest. 2018;128(9):4025-4043. https://doi.org/10.1172/JCI96063.
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Research Article Angiogenesis Vascular biology

Epsin deficiency promotes lymphangiogenesis through regulation of VEGFR3 degradation in diabetes

Abstract

Impaired lymphangiogenesis is a complication of chronic complex diseases, including diabetes. VEGF-C/VEGFR3 signaling promotes lymphangiogenesis, but how this pathway is affected in diabetes remains poorly understood. We previously demonstrated that loss of epsins 1 and 2 in lymphatic endothelial cells (LECs) prevented VEGF-C–induced VEGFR3 from endocytosis and degradation. Here, we report that diabetes attenuated VEGF-C–induced lymphangiogenesis in corneal micropocket and Matrigel plug assays in WT mice but not in mice with inducible lymphatic-specific deficiency of epsins 1 and 2 (LEC-iDKO). Consistently, LECs isolated from diabetic LEC-iDKO mice elevated in vitro proliferation, migration, and tube formation in response to VEGF-C over diabetic WT mice. Mechanistically, ROS produced in diabetes induced c-Src–dependent but VEGF-C–independent VEGFR3 phosphorylation, and upregulated epsins through the activation of transcription factor AP-1. Augmented epsins bound to and promoted degradation of newly synthesized VEGFR3 in the Golgi, resulting in reduced availability of VEGFR3 at the cell surface. Preclinically, the loss of lymphatic-specific epsins alleviated insufficient lymphangiogenesis and accelerated the resolution of tail edema in diabetic mice. Collectively, our studies indicate that inhibiting expression of epsins in diabetes protects VEGFR3 against degradation and ameliorates diabetes-triggered inhibition of lymphangiogenesis, thereby providing a novel potential therapeutic strategy to treat diabetic complications.

Authors

Hao Wu, H.N. Ashiqur Rahman, Yunzhou Dong, Xiaolei Liu, Yang Lee, Aiyun Wen, Kim H.T. To, Li Xiao, Amy E. Birsner, Lauren Bazinet, Scott Wong, Kai Song, Megan L. Brophy, M. Riaj Mahamud, Baojun Chang, Xiaofeng Cai, Satish Pasula, Sukyoung Kwak, Wenxia Yang, Joyce Bischoff, Jian Xu, Diane R. Bielenberg, J. Brandon Dixon, Robert J. D’Amato, R. Sathish Srinivasan, Hong Chen

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Figure 2

Epsin deficiency promotes proliferation, migration, and tube formation of lymphatic endothelial cells in vitro.

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Epsin deficiency promotes proliferation, migration, and tube formation o...
(A) Fluorescence intensity of DCF indicates the ROS levels in primary LECs from WT, LEC-iDKO, WT/STZ/HFD, and LEC-iDKO/STZ/HFD mice. (B) Representative immunofluorescence staining of Ki67 (red) and Prox1 (green) in WT, LEC-iDKO, WT/STZ/HFD, and LEC-iDKO/STZ/HFD LECs after treatment with 100 ng/mL VEGF-C for 24 hours. (C) Quantification of Ki67 staining in B. (D) Representative images of WT, LEC-iDKO, WT/STZ/HFD, and LEC-iDKO/STZ/HFD LECs cultured in LEC medium for 5 days, then subjected to a scratch assay in the absence or presence of 100 ng/mL VEGF-C for 12 hours. (E) Quantification of wound distance in D. (F) Representative images of WT, LEC-iDKO, WT/STZ/HFD, and LEC-iDKO/STZ/HFD LECs cultured in LEC medium for 5 days, then subjected to a tube formation assay by culturing on Matrigel for 16 hours in the absence or presence of 100 ng/mL VEGF-C for 12 hours. (G) Quantification of tube formation in F. Data are mean ± SEM, n = 7. *P < 0.05, **P < 0.01, by 2-way ANOVA followed by Tukey’s post hoc test. Scale bars: 100 μm (B), 50 μm (D and F).