Nrf2 mediates the effect of IR-61 on antibacterial activity of macrophages. (a) Relative mRNA levels of a panel of phagocytic receptors genes in PMs (Control vs IR-61 p = 0.1514 (Cd11a), p = 0.8793 (Cd11b), p = 0.9663 (Cd16), p = 0.1358 (Cd36), p = 0.4967 (Cd71), p = 0.1188 (Cd86), p = 0.6992 (Cd107), p = 0.2513 (Cd209a), p = 0.2900 (Cd212), p = 0.3309 (F4/80), p < 0.0001 (Marco), p = 0.0468 (Msr1); n = 3 per group). (b) Immunoblots for Marco, Msr1, and Nrf2 in whole cell lysates from the PMs treated with IR-61 for the indicated times. β-actin was used as the loading control. (c) Immunoblots for Marco, Msr1, and Nrf2 in whole cell lysates from PMs treated with IR-61 for 24 h or 48 h after transfection with siCtrl or siNrf2. β-actin was used as the loading control. (d, e) Uptake of latex beads (d) (siCtrl vs siCtrl IR-61 p < 0.0001, Marco siRNA (siMarco) vs siMarco IR-61 p = 0.6984; n = 5 per group) or pHrodo-labelled E. coli(e) (siCtrl vs siCtrl IR-61 p < 0.0001, siMarco vs siMarco IR-61 p = 0.2269; n = 3 per group) was measured using flow cytometry in the PMs treated with IR-61 for 24 h after transfection with siCtrl or siMarco. (f, g) Uptake of latex beads (f) (siCtrl vs siCtrl IR-61 p < 0.0001, siNrf2 vs siNrf2 IR-61 p = 0.1216; n = 3 per group) or pHrodo-labelled E. coli(g) (siCtrl vs siCtrl IR-61 p < 0.0001, siNrf2 vs siNrf2 IR-61 p = 0.8871; n = 5 per group) was measured using flow cytometry in the PMs treated with IR-61 for 24 h after transfection with siCtrl or siNrf2. (h) Intracellular bacterial CFUs were determined in PMs treated with IR-61 for 24 h after transfection with siCtrl or siNrf2 (siCtrl vs siCtrl IR-61 p = 0.0002 (S. aureus), p = 0.0034 (E. coli), siNrf2 vs siNrf2 IR-61 p = 0.6576 (S. aureus), p = 0.4892 (E. coli); n = 4 per group). Results are presented as the mean ± SD (∗p < 0.05, ∗∗p < 0.01, and ∗∗∗p < 0.001; two-sided Student's t-test).