Norepinephrine induces apoptosis in neonatal rat endothelial cells via a ROS-dependent JNK activation pathway

Abstract

Our previous study demonstrated that norepinephrine (NE) induces endothelial apoptosis mainly through down-regulation of Bcl-2 protein and activation of the beta-adrenergic and caspase-2 pathways. However, whether reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) are involved in this signal transduction remains unknown. Endothelial cells cultured from neonatal rat heart were treated with 100 microM NE. Proteins of MAPKs and Bcl-2 family were assayed by Western blotting. Apoptosis was determined by terminal deoxynucleotidyl transferase-mediated nick end-labeling assay. ROS was analyzed with flow cytometry. Caspase activity was measured using specific fluorogenic substrates. Treatment with NE increased intracellular ROS level and extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 phosphorylation. Whereas the phosphorylated form of Akt was decreased. The NE-induced apoptosis was abrogated by SP600125 (a specific inhibitor of JNK). Antioxidants such as vitamin C and N-acetyl cysteine inhibited NE-induced ROS production, JNK phosphorylation, caspase activation and apoptosis. Exogenously added superoxide dismutase or catalase markedly diminished NE-induced ROS production and cell death. In conclusions, our study is the first report documenting that NE induces apoptosis in neonatal rat endothelial cells via a ROS-dependent JNK activation pathway. Antioxidants may be useful in the prevention and management of NE-mediated endothelial apoptosis during heart failure.

Convergent ERK1/2, p38 and JNK mitogen activated protein kinases (MAPKs) signalling mediate catecholoestradiol‐induced proliferation of ovine uterine artery endothelial cells

“…Temporal activation of p38 in endothelial cells with E 2 β and β-AR stimulation has been associated with regulation of angiogenesis through cell migration or proliferation (Razandi et al 2000;Geraldes et al 2002;Iaccarino et al 2005). Conversely, the role of JNK activation in cell proliferation has proven controversial; while some report increased proliferation (Prifti et al 2001;Ryoo & Bergmann, 2012), others report anti-angiogenic effects (Fu et al 2006;Altiok et al 2007). Still, the phosphorylation patterns, alone, obtained in the current study do not provide sufficient evidence supporting a mitogenic or anti-angiogenic role of either p38 or JNK in P-UAECs.…”

Enteric glial cells counteract Clostridium difficile Toxin B through a NADPH oxidase/ROS/JNK/caspase-3 axis, without involving mitochondrial pathways

“…4C). These results are in line with the distinguished role of activated ERK and JNK, the former in regulating cell differentiation and growth, the latter oriented towards stress-responsive gene expression and apoptosis272829.…”

SOD1 and MitoTEMPO partially prevent mitochondrial permeability transition pore opening, necrosis, and mitochondrial apoptosis after ATP depletion recovery

“…JNK signaling has been shown to be involved in ROS-mediated apoptosis [48–51] facilitating the mitochondrial translocation of Bax. Increased phosphorylation of JNK within one hour of ATP depletion (and within 15 minutes of recovery) was observed in the current study, and SOD1 over-expression but not MitoTEMPO treatment tended to decrease JNK phosphorylation in both serum free and ATP-DR conditions.…”