Hypoxia-responsive miRNAs target argonaute 1 to promote angiogenesis
Zhen Chen, … , Michael Hsiao, John Y-J. Shyy
Zhen Chen, … , Michael Hsiao, John Y-J. Shyy
Published February 15, 2013
Citation Information: J Clin Invest. 2013;123(3):1057-1067. https://doi.org/10.1172/JCI65344.
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Research Article Oncology

Hypoxia-responsive miRNAs target argonaute 1 to promote angiogenesis

Abstract

Despite a general repression of translation under hypoxia, cells selectively upregulate a set of hypoxia-inducible genes. Results from deep sequencing revealed that Let-7 and miR-103/107 are hypoxia-responsive microRNAs (HRMs) that are strongly induced in vascular endothelial cells. In silico bioinformatics and in vitro validation showed that these HRMs are induced by HIF1α and target argonaute 1 (AGO1), which anchors the microRNA-induced silencing complex (miRISC). HRM targeting of AGO1 resulted in the translational desuppression of VEGF mRNA. Inhibition of HRM or overexpression of AGO1 without the 3′ untranslated region decreased hypoxia-induced angiogenesis. Conversely, AGO1 knockdown increased angiogenesis under normoxia in vivo. In addition, data from tumor xenografts and human cancer specimens indicate that AGO1-mediated translational desuppression of VEGF may be associated with tumor angiogenesis and poor prognosis. These findings provide evidence for an angiogenic pathway involving HRMs that target AGO1 and suggest that this pathway may be a suitable target for anti- or proangiogenesis strategies.

Authors

Zhen Chen, Tsung-Ching Lai, Yi-Hua Jan, Feng-Mao Lin, Wei-Chi Wang, Han Xiao, Yun-Ting Wang, Wei Sun, Xiaopei Cui, Ying-Shiuan Li, Tzan Fang, Hongwei Zhao, Chellappan Padmanabhan, Ruobai Sun, Danny Ling Wang, Hailing Jin, Gar-Yang Chau, Hsien-Da Huang, Michael Hsiao, John Y-J. Shyy

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Figure 6

HRM/AGO1 pathway regulates hypoxia-induced angiogenesis in vivo.

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HRM/AGO1 pathway regulates hypoxia-induced angiogenesis in vivo. (A–C) M...
(A–C) Matrigel mixed with control RNA (15 μg/plug) or antagomirs against Let-7a, Let-7e, and miR-103 (5 μg/plug each) was injected s.c. into C57BL/6 mice before 5-day normoxia or hypoxia. Gross morphology (A) and Hb quantification (B) as well as H&E, vWF, and CD31 staining of Matrigel plugs (C). (D and E) HUVECs transfected with control or HA-AGO1-ORF plasmid were mixed with Matrigel and s.c. injected into SCID mice, which were then kept under normoxia or hypoxia for 3 days. Gross morphology (D) was photographed and Hb quantified (E). (F–H) HUVECs transfected with control RNA (40 nM) or AGO1 siRNA (20 or 40 nM) were mixed with Matrigel and s.c. injected into SCID mice. Five days after injection, the plugs were harvested for gross morphology (F), Hb quantification (G), histology, and IHC (H). In C, E, and G, the Hb content in normoxia/control RNA or control plasmid group was set to 1. Bar graphs represent mean ± SEM. Results are from 5–10 animals per group. Scale bar: 100 μm. *P < 0.05 compared with controls or between indicated groups.