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Lung endothelial HO‐1 targeting in vivo using lentiviral miRNA regulates apoptosis and autophagy during oxidant injury

The lung endothelium is a major target for inflammatory and oxidative stress. Heme oxygenase‐1 (HO‐1) induction is a crucial defense mechanism during oxidant challenges, such as hyperoxia. The role of lung endothelial HO‐1during hyperoxia in vivo is not well defined. We engineered lentiviral vectors with microRNA (miRNA) sequences controlled by vascular endothelium cadherin (VE‐cad) to study the specific role of lung endothelial HO‐1. Wild‐type (WT) murine lung endothelial cells (MLECs) or WT mice were treated with lentivirus and exposed to hyperoxia (95% oxygen). We detected HO‐1 knockdown (~55%) specifically in the lung endothelium. MLECs and lungs showed approximately a 2‐fold increase in apoptosis and ROS generation after HO‐1 silencing. We also demonstrate for the first time that silencing endothelial HO‐1 has the same effect on lung injury and survival as silencing HO‐1 in multiple lung cell types and that HO‐1 regulates caspase 3 activation and autophagy in endothelium during hyperoxia. These studies demonstrate the utility of endothelial‐targeted gene silencing in vivo using lentiviral miRNA constructs to assess gene function and that endothelial HO‐1 is an important determinant of survival during hyperoxia.—Zhang, Y., Jiang, G., Sauler, M., Lee, P. J., Lung endothelial HO‐1 targeting in vivo using lentiviral miRNA regulates apoptosis and autophagy during oxidant injury. FASEB J. 27, 4041–4058 (2013). www.fasebj.org