NPR3 protects cardiomyocytes from apoptosis through inhibition of cytosolic BRCA1 and TNF-α

Figures & data

Figure 1. Enhancement of caspase activities in natriuretic peptide receptor 3 (NPR3) knock-down cardiomyocyte H9C2 cells. Immunoblot analysis of NPR3 and caspases was performed in lysates of NPR3 knock-down and control H9C2 cells treated with or without a selective NPR3 agonist ring-deleted analog of atrial natriuretic factor (cANF).

Figure 2. Effects of H₂O₂ on NPR3 knock-down H9C2 cell viability. Cells were incubated with increasing concentrations of H₂O₂ (0 to 250 nM) for 18 hours. Cell viability was measured by MTS assay. A significant decrease in cell viability with increased H₂O₂ concentration was observed in NPR3 knock-down H9C2 cells (P < 0 .05).

Figure 3. Upregulation of breast cancer type 1 susceptibility protein (BRCA1), cAMP response element-binding protein (CREB) and cAMP-dependent protein kinase (PKA) in NPR3 knock-down H9C2 cells. Immunoblot analysis of NPR3, BRCA1, CREB and PKA was performed in lysates of NPR3 knock-down and control H9C2 cells treated with or without a selective NPR3 agonist Canf.

Figure 4. Cytoplasmic localization of BRCA1 in H9C2 cardiomyocytes. Cells were exposed to 5 Gy of X-ray and subjected to immunofluorescent analysis 1 hour after irradiation with anti- BRCA1 (red), γH2AX (green) antibodies. Nuclei were stained with DAPI (blue). Scale bar, 50 um.

Figure 5. Up-regulation of tumor necrosis factor α (TNF-α) in NPR3 knock-down H9C2 cells. Immunoblot analysis of NPR3 and TNF-α was performed in lysates of NPR3 knock-down and control H9C2 cells treated with or without a selective NPR3 agonist cANF.