Fig. 2.
High-mobility group box-1 protein (HMGB-1) increases epithelial Na+ channel (ENaC) open probability (Po) in small airway epithelial cells (SAECs). A: representative trace of continuous single-channel recording before and after application of 0.5 μg/mL HMGB-1 to the extracellular bath. A portion of the single-channel recording was expanded between 23 and 27 min to show single-channel detail; # demarks a break in the continuous trace. Arrows indicate closed state (C); downward deflections from arrows indicate channel openings. B: highly selective cation (HSC, 4.25 pS) and nonselective cation (18.86 pS) channels under control condition and following HMGB-1 application to extracellular bath. C: HMGB-1 significantly increases ENaC Po in normal SAECs (n = 21 independent patch-clamp recordings from SAECs obtained from 5 different healthy male and female donor lungs) and CF SAECs (n = 6 independent patch-clamp recordings from SAECs obtained from 1 female CF donor lung). CTR, control. *P < 0.05, before vs. after HMGB-1 application (evaluated using the paired t-test).