α-Chemokine receptor blockade reduces high mobility group box 1 protein-induced lung inflammation and injury and improves survival in sepsis

High mobility group box 1 (HMGB1) protein, a late mediator of lethality in sepsis, can induce acute inflammatory lung injury. Here, we identify the critical role of α-chemokine receptors in the HMGB1-induced inflammatory injury and show that α-chemokine receptor inhibition increases survival in sepsis, in a clinically relevant time frame. Intratracheal instillation of recombinant HMGB1 induces a neutrophilic leukocytosis, preceded by alveolar accumulation of the α-chemokine macrophage inflammatory protein-2 and accompanied by injury and increased inflammatory potential within the air spaces. To investigate the role of α-chemokine receptors in the injury, we instilled recombinant HMGB1 (0.5 μg) directly into the lungs and administered a subcutaneous α-chemokine receptor inhibitor, Antileukinate (200 μg). α-Chemokine receptor blockade reduced HMGB1-induced inflammatory injury (neutrophils: 2.9 ± 3.2 vs. 8.1 ± 2.4 × 10 4 cells; total protein: 120 ± 48 vs. 311 ± 129 μg/ml; reactive nitrogen species: 2.3 ± 0.3 vs. 3.5 ± 1.3 μM; and macrophage migration inhibitory factor: 6.4 ± 4.2 vs. 37.4 ± 15.9 ng/ml) within the bronchoalveolar lavage fluid, indicating that HMGB1-induced inflammation and injury are α-chemokine mediated. Because HMGB1 can mediate late septic lethality, we administered Antileukinate to septic mice and observed increased survival (from 58% in controls to 89%) even when the inhibitor treatment was initiated 24 h after the induction of sepsis. These data demonstrate that α-chemokine receptor inhibition can reduce HMGB1-induced lung injury and lethality in established sepsis and may provide a novel treatment in this devastating disease.