Protein S-glutathionylation (
PSSG), a reversible posttranslational modification of reactive cysteines, recently emerged as a regulatory mechanism that affects diverse cell-signaling cascades. The extent of cellular
PSSG is controlled by the
oxidoreductase glutaredoxin-1 (Grx1), a cytosolic
enzyme that specifically de-glutathionylates
proteins. Here, we sought to evaluate the impact of the genetic ablation of Grx1 on
PSSG and on LPS-induced
lung inflammation. In response to LPS, Grx1 activity increased in lung tissue and bronchoalveolar lavage (BAL) fluid in WT (WT) mice compared with PBS control mice. Glrx1(-/-) mice consistently showed slight but statistically insignificant decreases in total numbers of inflammatory cells recovered by BAL. However, LPS-induced concentrations of IL-1β, TNF-α,
IL-6, and Granulocyte/Monocyte
Colony-Stimulating Factor (
GM-CSF) in BAL were significantly decreased in Glrx1(-/-) mice compared with WT mice. An in situ assessment of
PSSG reactivity and a biochemical evaluation of
PSSG content demonstrated increases in the lung tissue of Glrx1(-/-) animals in response to LPS, compared with WT mice or PBS control mice. We also demonstrated that
PSSG reactivity was prominent in alveolar macrophages (AMs). Comparative BAL analyses from WT and Glrx1(-/-) mice revealed fewer and smaller AMs in Glrx1(-/-) mice, which showed a significantly decreased expression of NF-κB family members, impaired nuclear translocation of RelA, and lower levels of NF-κB-dependent
cytokines after exposure to LPS, compared with WT cells. Taken together, these results indicate that Grx1 regulates the production of inflammatory mediators through control of S-glutathionylation-sensitive signaling pathways such as NF-κB, and that Grx1 expression is critical to the activation of AMs.