Angiopoietin receptor Tie2 is required for vein specification and maintenance via regulating COUP-TFII.

eLife 2016 Dec 22

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Mechanisms underlying the vein development remain largely unknown. Tie2 signaling mediates endothelial cell (EC) survival and vascular maturation and its activating mutations are linked to venous malformations. Here we show that vein formation are disrupted in mouse skin and mesentery when Tie2 signals are diminished by targeted deletion of Tek either ubiquitously or specifically in embryonic ECs. Postnatal Tie2 attenuation resulted in the degeneration of newly formed veins followed by the formation of haemangioma-like vascular tufts in retina and venous tortuosity. Mechanistically, Tie2 insufficiency compromised venous EC identity, as indicated by a significant decrease of COUP-TFII protein level, a key regulator in venogenesis. Consistently, angiopoietin-1 stimulation increased COUP-TFII in cultured ECs, while Tie2 knockdown or blockade of Tie2 downstream PI3K/Akt pathway reduced COUP-TFII which could be reverted by the proteasome inhibition. Together, our results imply that Tie2 is essential for venous specification and maintenance via Akt mediated stabilization of COUP-TFII.

Citation

Man Chu, Taotao Li, Bin Shen, Xudong Cao, Haoyu Zhong, Luqing Zhang, Fei Zhou, Wenjuan Ma, Haijuan Jiang, Pancheng Xie, Zhengzheng Liu, Ningzheng Dong, Ying Xu, Yun Zhao, Guoqiang Xu, Peirong Lu, Jincai Luo, Qingyu Wu, Kari Alitalo, Gou Young Koh, Ralf H Adams, Yulong He. Angiopoietin receptor Tie2 is required for vein specification and maintenance via regulating COUP-TFII. eLife. 2016 Dec 22;5