Exogenous administration of heme oxygenase-1 by gene transfer provides protection against hyperoxia-induced lung injury

• Published in: The Journal of clinical investigation Vol. 103; no. 7; pp. 1047 - 1054
• Main Authors: Otterbein, L E, Kolls, J K, Mantell, L L, Cook, J L, Alam, J, Choi, A M
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Investigation 01.04.1999
• Subjects: Adenoviridae - genetics; Animals; Apoptosis - genetics; Bronchoalveolar Lavage Fluid - cytology; Gene Expression Regulation, Enzymologic - genetics; Gene Transfer Techniques; Heme Oxygenase (Decyclizing) - genetics; Heme Oxygenase (Decyclizing) - pharmacology; Heme Oxygenase-1; Hyperoxia - physiopathology; Immunohistochemistry; Lung - metabolism; Lung - physiopathology; Oxidative Stress; Oxygen - toxicity; Pleural Effusion - pathology; Rats; Rats, Sprague-Dawley; RNA, Messenger - metabolism; Superoxide Dismutase - genetics
• ISSN: 0021-9738
• DOI: 10.1172/jci5342

Heme oxygenase-1 (HO-1) confers protection against a variety of oxidant-induced cell and tissue injury. In this study, we examined whether exogenous administration of HO-1 by gene transfer could also confer protection. We first demonstrated the feasibility of overexpressing HO-1 in the lung by gene transfer. A fragment of the rat HO-1 cDNA clone containing the entire coding region was cloned into plasmid pAC-CMVpLpA, and recombinant adenoviruses containing the rat HO-1 cDNA fragment Ad5-HO-1 were generated by homologous recombination. Intratracheal administration of Ad5-HO-1 resulted in a time-dependent increase in expression of HO-1 mRNA and protein in the rat lungs. Increased HO-1 protein expression was detected diffusely in the bronchiolar epithelium of rats receiving Ad5-HO-1, as assessed by immunohistochemical studies. We then examined whether ectopic expression of HO-1 could confer protection against hyperoxia-induced lung injury. Rats receiving Ad5-HO-1, but not AdV-betaGal, a recombinant adenovirus expressing Escherichia coli beta-galactosidase, before exposure to hyperoxia (>99% O2) exhibited marked reduction in lung injury, as assessed by volume of pleural effusion and histological analyses (significant reduction of edema, hemorrhage, and inflammation). In addition, rats receiving Ad5-HO-1 also exhibited increased survivability against hyperoxic stress when compared with rats receiving AdV-betaGal. Expression of the antioxidant enzymes manganese superoxide dismutase (Mn-SOD) and copper-zinc superoxide dismutase (CuZn-SOD) and of L-ferritin and H-ferritin was not affected by Ad5-HO-1 administration. Furthermore, rats treated with Ad5-HO-1 exhibited attenuation of hyperoxia-induced neutrophil inflammation and apoptosis. Taken together, these data suggest the feasibility of high-level HO-1 expression in the rat lung by gene delivery. To our knowledge, we have demonstrated for the first time that HO-1 can provide protection against hyperoxia-induced lung injury in vivo by modulation of neutrophil inflammation and lung apoptosis.