TY - JOUR
T1 - Innate immunity against bacterial infection following hyperoxia exposure is impaired in NRF2-deficient mice
AU - Reddy, Narsa M.
AU - Suryanarayana, Vegiraju
AU - Kalvakolanu, Dhananjaya V.
AU - Yamamoto, Masayuki
AU - Kensler, Thomas W.
AU - Hassoun, Paul M.
AU - Kleeberger, Steven R.
AU - Reddy, Sekhar P.
PY - 2009/10/1
Y1 - 2009/10/1
N2 - Oxygen supplementation is used as therapy to support critically ill patients with severe respiratory impairment. Although hyperoxia has been shown to enhance the lung susceptibility to subsequent bacterial infection, the mechanisms underlying enhanced susceptibility remain enigmatic. We have reported that disruption of NF-E2-related factor 2 (Nrf2), a master transcription regulator of various stress response pathways, enhances susceptibility to hyperoxia-induced acute lung injury in mice, and have also demonstrated an association between a polymorphism in the NRF2 promoter and increased susceptibility to acute lung injury. In this study, we show that Nrf2-deficient (Nrf2-/-) but not wild-type (Nrf2+/+) mice exposed to sublethal hyperoxia succumbed to death during recovery after Pseudomonas aeruginosa infection. Nrf2-deficiency caused persistent bacterial pulmonary burden and enhanced levels of inflammatory cell infiltration as well as edema. Alveolar macrophages isolated from Nrf2-/- mice exposed to hyperoxia displayed persistent oxidative stress and inflammatory cytokine expression concomitant with diminished levels of antioxidant enzymes, such as Gclc, required for glutathione biosynthesis. In vitro exposure of Nrf2-/- macrophages to hyperoxia strongly diminished their antibacterial activity and enhanced inflammatory cytokine expression compared with Nrf2+/+ cells. However, glutathione supplementation during hyperoxic insult restored the ability of Nrf2-/- cells to mount antibacterial response and suppressed cytokine expression. Thus, loss of Nrf2 impairs lung innate immunity and promotes susceptibility to bacterial infection after hyperoxia exposure, ultimately leading to death of the host.
AB - Oxygen supplementation is used as therapy to support critically ill patients with severe respiratory impairment. Although hyperoxia has been shown to enhance the lung susceptibility to subsequent bacterial infection, the mechanisms underlying enhanced susceptibility remain enigmatic. We have reported that disruption of NF-E2-related factor 2 (Nrf2), a master transcription regulator of various stress response pathways, enhances susceptibility to hyperoxia-induced acute lung injury in mice, and have also demonstrated an association between a polymorphism in the NRF2 promoter and increased susceptibility to acute lung injury. In this study, we show that Nrf2-deficient (Nrf2-/-) but not wild-type (Nrf2+/+) mice exposed to sublethal hyperoxia succumbed to death during recovery after Pseudomonas aeruginosa infection. Nrf2-deficiency caused persistent bacterial pulmonary burden and enhanced levels of inflammatory cell infiltration as well as edema. Alveolar macrophages isolated from Nrf2-/- mice exposed to hyperoxia displayed persistent oxidative stress and inflammatory cytokine expression concomitant with diminished levels of antioxidant enzymes, such as Gclc, required for glutathione biosynthesis. In vitro exposure of Nrf2-/- macrophages to hyperoxia strongly diminished their antibacterial activity and enhanced inflammatory cytokine expression compared with Nrf2+/+ cells. However, glutathione supplementation during hyperoxic insult restored the ability of Nrf2-/- cells to mount antibacterial response and suppressed cytokine expression. Thus, loss of Nrf2 impairs lung innate immunity and promotes susceptibility to bacterial infection after hyperoxia exposure, ultimately leading to death of the host.
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U2 - 10.4049/jimmunol.0901754
DO - 10.4049/jimmunol.0901754
M3 - Article
C2 - 19734219
AN - SCOPUS:70449723401
SN - 0022-1767
VL - 183
SP - 4601
EP - 4608
JO - Journal of Immunology
JF - Journal of Immunology
IS - 7
ER -