Western Blot Analysis of Kidney Proteins

Western blots were performed as previously described [25 (link)]. Total protein was extracted from kidney tissue in RIPA lysis buffer (25 mM Tris-HCl, 25 mM NaCl, 0.5 mM EDTA, 1% Triton X-100, and 0.1% SDS) with 1% PMSF protease inhibitors (P1005, Beyotime Biotechnology, China) and phosphatase inhibitors (P1081, Beyotime Biotechnology, China) added. Equal amounts of protein were separated by 10-15% SDS-PAGE and then transferred to PVDF membranes (IPVH00010, Millipore, Germany). After blocking with 5% nonfat milk for 3 h, the membranes were incubated with the primary antibodies including TGF-β1, α-SMA, Nrf2, HO-1, NQO1, ASC, caspase-1 (ab215715, ab32575, ab137550, ab13248, ab80588, ab175449, ab1872, Abcam, UK), p-Smad2, Smad2, p-Smad3, Smad3, E-cadherin, NLRP3 ((#18338, #5339, #9520, #9523, #3195, #15101, Cell Signaling Technology, USA), and cleaved caspase-1 (AF4005, Affinity Biosciences, USA) at 4°C overnight. Then, the membranes were washed 3 times with TBST and incubated with the secondary antibodies for 1 h at room temperature. After washing with TBST for a further three times, the protein bands were visualized by enhanced chemiluminescence (32134, Thermo, USA) solution and imaged with Automated Imaging System (Gene Gnome5, Synoptics Ltd, UK). GAPDH or β-actin was assumed to be similarly abundant in all samples and was used as a loading control.