Cytoplasmic and Nuclear Protein Isolation

The cytoplasm and nuclei in LV tissue and RAW264.7 macrophages were isolated using a nuclear separation kit (Njjcbio) according to a previously described protocol [19 (link)]. Briefly, homogenate was collected from LV tissue and cells that were lysed in lysis buffer and further centrifuged at 1000 × g for 10 minutes. The pellets in the bottoms of the tubes contained the nuclei, and the supernatant contained the cytoplasm.
After the cytoplasm, nuclei, LV tissue, and HL-1 cardiomyocytes were, respectively, lysed in RIPA lysis buffer containing 10% protease inhibitors and 10% phosphatase inhibitors, the total protein was obtained and quantitated using a BCA Protein Assay Kit. After separation by electrophoresis on 10% SDS polyacrylamide gels, the proteins were transferred to PVDF membranes. Then, the protein expression of IL-16 (Abcam), Bax, Bcl-2, cleaved caspase-3, caspase-3, and GAPDH (all three from GeneTex) in total LV tissue, the protein expression of p-p65 and GAPDH (both from Abcam) in the cytoplasm, the protein expression of p-p65 and PCNA (GeneTex) in the nuclei, and the protein expression of Bax, Bcl-2, cleaved caspase-3, caspase-3, and GAPDH in HL-1 cardiomyocytes were measured using primary antibodies as indicated in parentheses. After further incubation with the secondary antibodies, the target proteins were detected and analyzed.