CTSB promotes pyroptosis through NF-κB signaling in VSMCs.

(A) Representative images of NF-κB-p65 (red) immunofluorescence and DAPI (blue) staining of ox-LDL-treated VSMCs (scale bar: 20 μm). NC: VSMCs without any treatment; CTRL: VSMCs treated with 150 μg/ml ox-LDL for 24 h. Mock: empty lentiviral vector + ox-LDL; sh-CTSB: CTSB shRNA + ox-LDL; Lv-CTSB: CTSB lentivirus + oxLDL. (B) Representative images of NF-κB-p65 (red) immunofluorescence and DAPI (blue) staining of Lv-CTSB- and ox-LDL-treated VSMCs (scale bar: 20 μm). CTRL: Lv-CTSB + ox-LDL; PBS: Lv-CTSB + ox-LDL + PBS; SN50: Lv-CTSB + ox-LDL + SN50 (75 μg/ml). (C) Representative western blots of IκB-α and NF-κB-p65 in ox-LDL-treated VSMCs. (D) Representative western blots of IκB-α and NF-κB-p65 in Lv-CTSB + ox-LDL–treated VSMCs. (E–H) Quantification of protein levels in VSMCs: (E) p-IκBα in ox-LDL-treated VSMCs, (F) p-NF-κB-p65 in ox-LDL-treated VSMCs, (G) p-IκBα in Lv-CTSB + ox-LDL-treated VSMCs, and (H) p-NF-κB-p65 in Lv-CTSB + ox-LDL-treated VSMCs. p-IκB-α: phosphorylated IκB-α; T-IκB-α: total IκB-α); p-NF-κB-p65: phosphorylated NF-κB-p65; T-NF-κB-p65: total NF-κB-p65. Data are presented as means ± SEM. n = 3, *P<0.05, **P<0.01, ***P<0.001, and ****P<0.0001.ox-LDL: oxidized low-density lipoprotein; CTSB: cathepsin B; VSMCs: vascular smooth muscle cells.