C6 peptide blockade of Hv1 channels inhibits neutrophil migration into the lungs to suppress Pseudomonas aeruginosa-induced acute lung injury.

Summary

In a live Pseudomonas aeruginosa ALI model, the Hv1-blocking peptide C6 reduced alveolar neutrophil influx by about 86%, improved histologic lung injury, and lowered BAL cytokines, neutrophil ROS, and intracellular calcium. Transcriptomics of BAL neutrophils showed coordinated downregulation of genes regulating migration and ROS; human neutrophils exhibited parallel inhibition of chemotaxis and activation.

Key Findings

• C6 reduced neutrophil infiltration into the alveolar space by approximately 86% in a live Pseudomonas aeruginosa ALI model.
• C6 improved lung injury scores and decreased BAL proinflammatory cytokines, neutrophil ROS production, and intracellular calcium.
• RNA-seq of BAL neutrophils showed 51 genes downregulated (migration, cytokine release, ROS pathways), with parallel suppression of chemotaxis and activation in human neutrophils.

Clinical Implications

While preclinical, these results support Hv1 inhibition as a strategy to limit neutrophil-mediated tissue damage in severe pneumonia/ALI, warranting pharmacokinetics, safety, and delivery studies toward early-phase clinical trials.

Limitations

• Preclinical study without survival outcomes or long-term safety data.
• Potential off-target effects, optimal dosing, and delivery route for C6 remain uncharacterized.

Future Directions

Evaluate pharmacology, safety, and delivery (e.g., inhalation) in larger animal models; test efficacy across diverse ALI etiologies and progress toward phase I trials.