Portal de Periódicos da CAPES

Modulation of reactive oxygen species by Rac1 or catalase prevents asbestos-induced pulmonary fibrosis

2009; American Physical Society; Volume: 297; Issue: 5 Linguagem: Inglês

10.1152/ajplung.90590.2008

1522-1504

Shubha Murthy, Andrea Adamcakova‐Dodd, Sarah S. Perry, Linda A. Tephly, Richard M. Keller, Nervana Metwali, David K. Meyerholz, Yongqiang Wang, Michael Glogauer, Peter S. Thorne, A. Brent Carter,

Occupational exposure and asthma

The release of reactive oxygen species (ROS) and cytokines by alveolar macrophages has been demonstrated in asbestos-induced pulmonary fibrosis, but the mechanism linking alveolar macrophages to the pathogenesis is not known. The GTPase Rac1 is a second messenger that plays an important role in host defense. In this study, we demonstrate that Rac1 null mice are protected from asbestos-induced pulmonary fibrosis, as determined by histological and biochemical analysis. We hypothesized that Rac1 induced pulmonary fibrosis via generation of ROS. Asbestos increased TNF-alpha and ROS in a Rac1-dependent manner. TNF-alpha was elevated only 1 day after exposure, whereas ROS generation progressively increased in bronchoalveolar lavage cells obtained from wild-type (WT) mice. To determine whether ROS generation contributed to pulmonary fibrosis, we overexpressed catalase in WT monocytes and observed a decrease in ROS generation in vitro. More importantly, administration of catalase to WT mice attenuated the development of fibrosis in vivo. For the first time, these results demonstrate that Rac1 plays a crucial role in asbestos-induced pulmonary fibrosis. Moreover, it suggests that a simple intervention may be useful to prevent progression of the disease.