Suppression of NHE1 by small interfering RNA inhibits HIF-1α-induced angiogenesis in vitro via modulation of calpain activity.

Abstract

Hypoxia-inducible factor-1 (HIF-1) orchestrates angiogenesis under hypoxic conditions mainly due to increased expression of such target genes as vascular endothelial growth factor (VEGF). Na+/H+exchanger-1 (NHE1), a potential HIF target gene product, plays a pivotal role in proliferation, survival, migration, adhesion and so on. However, it is unknown whether NHE1 is involved in HIF-1α-induced angiogenesis. This present study demonstrated that the expression of NHE1 was much higher in human umbilical vein endothelial cells (HUVECs) infected with adenovirus encoding HIF-1α (rAd-HIF) than with vacuum adenovirus (vAd). HIF-1α also increased the expression of VEGF, the expression and activity of calpains, and the intracellular pH. Moreover, small interfering RNA targeting NHE1 (NHE1 siRNA) dramatically decreased the expression of NHE1 and thus lowered the intracellular pH, and it also attenuated the protein expression of calpain-2 but not calpain-1, resulting in the lower calpain activity. Furthermore, HIF-1α enhanced the proliferation, migration and Matrigel tube formation, which were inhibited by NHE1 siRNA. Finally, the inhibitory effect of NHE1 siRNA was reversed by VEGF and the reversibility of the later was abrogated by the calpain inhibitor ALLM. In conclusion, the findings have revealed that NHE1 might participate in HIF-1-induced angiogenesis due, at least in part, to the alteration of the calpain activity, suggesting that NHE1 as well as calpains might represent a potential target of controlling angiogenesis in response to the hypoxic stress under various pathological conditions.

• Authors: Xian-Gang Mo, Qing-Wei Chen, Xing-Sheng Li, Min-Ming Zheng, Da-Zhi Ke, Wei Deng, Gui-Qiong Li, Jin Jiang, Zhi-Qin Wu, Li Wang, Peng Wang, Yan Yang, Guang-Yi Cao
• Journal: Microvascular research (Microvasc Res) Vol. 81 Issue 2 Pg. 160-8 (Mar 2011) ISSN: 1095-9319 [Electronic] United States
• PMID: 21185840 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2010 Elsevier Inc. All rights reserved.

Chemical References

• Cation Transport Proteins
• Cysteine Proteinase Inhibitors
• HIF1A protein, human
• Hypoxia-Inducible Factor 1, alpha Subunit
• RNA, Small Interfering
• SLC9A1 protein, human
• Sodium-Hydrogen Exchanger 1
• Sodium-Hydrogen Exchangers
• VEGFA protein, human
• Vascular Endothelial Growth Factor A
• Calpain
• CAPN2 protein, human

Topics

• Calpain (antagonists & inhibitors, metabolism)
• Cation Transport Proteins (deficiency, genetics, metabolism)
• Cell Movement (drug effects, physiology)
• Cell Proliferation (drug effects)
• Cell Survival (genetics, physiology)
• Cells, Cultured
• Cysteine Proteinase Inhibitors (pharmacology)
• Cytoplasm (metabolism)
• Endothelial Cells (cytology, drug effects, metabolism)
• Gene Expression (genetics)
• Humans
• Hydrogen-Ion Concentration
• Hypoxia-Inducible Factor 1, alpha Subunit (genetics, metabolism)
• Neovascularization, Physiologic (drug effects, physiology)
• RNA, Small Interfering (genetics)
• Sodium-Hydrogen Exchanger 1
• Sodium-Hydrogen Exchangers (genetics, metabolism)
• Transduction, Genetic
• Up-Regulation (genetics)
• Vascular Endothelial Growth Factor A (genetics, metabolism, pharmacology)