Tumor necrosis factor-α-induced nuclear factor-kappaB activation in human cardiomyocytes is mediated by NADPH oxidase

Abstract

An elevated level of tumor necrosis factor (TNF)-α is implicated in several cardiovascular diseases including heart failure. Numerous reports have demonstrated that TNF-α activates nuclear factor (NF)-kappaB, resulting in the upregulation of several genes that regulate inflammation, proliferation, and apoptosis of cardiomyocytes. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, a major source of reactive oxygen species (ROS), is also activated by TNF-α and plays a crucial role in redox-sensitive signaling pathways. The present study investigated whether NADPH oxidase mediates TNF-α-induced NF-kappaB activation and NF-kappaB-mediated gene expression. Human cardiomyocytes were treated with recombinant TNF-α with or without pretreatment with diphenyleneiodonium (DPI) and apocynin, inhibitors of NADPH oxidase. TNF-α-induced ROS production was measured using 5-(and-6)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate assay. TNF-α-induced NF-kappaB activation was also examined using immunoblot; NF-kappaB binding to its binding motif was determined using a Cignal reporter luciferase assay and an electrophoretic mobility shift assay. TNF-α-induced upregulation of interleukin (IL)-1β and vascular cell adhesion molecule (VCAM)-1 was investigated using real-time PCR and immunoblot. TNF-α-induced ROS production in cardiomyocytes was mediated by NADPH oxidase. Phosphorylation of IKK-α/β and p65, degradation of IkappaBα, binding of NF-kappaB to its binding motif, and upregulation of IL-1β and VCAM-1 induced by TNF-α were significantly attenuated by treatment with DPI and apocynin. Collectively, these findings demonstrate that NADPH oxidase plays a role in regulation of TNF-α-induced NF-kappaB activation and upregulation of proinflammatory cytokines, IL-1β and VCAM-1, in human cardiomyocytes.

TNF-α in the cardiovascular system: from physiology to therapy

“…105 These phenomena are mediated by activation of p38MAPK and NF-κB 106 in a ROS-dependent manner. 105,[107][108][109] In line with these findings, in vivo studies demonstrated a hypertrophic response in cardiac myocytes, leading to left ventricular hypertrophy and dilatation upon cardiac-specific overexpression or chronic infusion of high doses of TNF-α. 94,105,110 Cardiac myocytes have further been shown to undergo apoptosis after stimulation with TNF-α in vitro.…”

The Adipokine Chemerin Induces Apoptosis in Cardiomyocytes

“…TNF-α is a pro-inflammatory cytokine that is closely related to the physiopathology of several cardiovascular diseases through the upregulation of genes that control inflammation, proliferation and apoptosis in cardiomyocytes [75]. Previous works have shown that other adipokines can modulate the effect of TNF-α, particularly the adipokine leptin, a crucial regulator of energy homeostasis that confers protection against the apoptosis induced by TNF-α [45].…”

Isocitrate Dehydrogenase 2 Suppresses the Invasion of Hepatocellular Carcinoma Cells via Matrix Metalloproteinase 9

“…Tumor cell growth and invasion are regulated by a network of factors, among which nuclear factor κB (NF-κB) is a critical one that regulates the expression of various genes involved in immunity, stress responses, inflammation and the inhibition of apoptosis, thus providing appropriate conditions for tumor cell progression [22][23][24]. NF-κB is constitutively activated in some tumor cells, including HCC cells, and contributes to the maintenance of the highly proliferative malignant phenotype as well as cellular invasion [22][23][24].…”