Kv1.3 gene silencing abolishes LPS- and DEX-dependent biophysical changes in macrophages. LTV shRNA (mouse) Kv1.3 was used to silence the Kv1.3 gene in Raw 264.7 macrophages. (A) A representative Western blot. Note that although Kv1.3 expression is lower in LTV, relative Kv1.5 abundance was similar in both groups. Raw, control macrophages; Raw-LTV, LTV-silenced Kv1.3 macrophages. (B) Representative traces of K+ currents in macrophages. Cells were held at −80 mV, and currents were elicited by a depolarizing pulse to +60 mV (250-ms duration). (C) Current density (pA/pF) versus voltage relationship of K+ currents. Current density was calculated as a function of peak amplitude and the capacitance of each recorded cell in the presence or absence of LPS and DEX. (D) Cell capacitance (pF) from the same cell population from B. (E) Representative traces of C-type inactivation. Cells were held at −80 mV, and pulse potentials were applied from −80 to +60 mV for 5 s. For comparison, the intensity in each group has been normalized. (F) Percentage of cumulative inactivation at the peak current. Cells were held at −80 mV, and currents were elicited by a train of eight depolarizing voltage steps (200-ms duration) to +60 mV once every 400 ms. The percentage was calculated as a result of the difference between the peak current at the first pulse and the remaining current at the last. (D and F) Raw, no infected Raw macrophages; Raw-LTV, lentivirus-infected Raw cells; white bars, control (no treatment); black bars, LPS; gray bars, DEX. Values are the mean ± SEM of six to eight independent cells. *, P < 0.001 versus control (Student’s t test).
