Reactive oxygen species regulate Smac mimetic/TNFα-induced necroptotic signaling and cell death

Abstract

Necroptosis represents a key programmed cell death pathway involved in various physiological and pathophysiological conditions. However, the role of reactive oxygen species (ROS) in necroptotic signaling has remained unclear. In the present study, we identify ROS as critical regulators of BV6/tumor necrosis factor-α (TNFα)-induced necroptotic signaling and cell death. We show that BV6/TNFα-induced cell death depends on ROS production, as several ROS scavengers such as butylated hydroxyanisole, N-acetylcysteine, α-tocopherol and ethyl pyruvate significantly rescue cell death. Before cell death, BV6/TNFα-stimulated ROS generation promotes stabilization of the receptor-interacting protein kinase 1 (RIP1)/RIP3 necrosome complex via a potential positive feedback loop, as on the one hand radical scavengers attenuate RIP1/RIP3 necrosome assembly and phosphorylation of mixed lineage kinase domain like (MLKL), but on the other hand silencing of RIP1 or RIP3 reduces ROS production. Although MLKL knockdown effectively decreases BV6/TNFα-induced cell death, it does not affect RIP1/RIP3 interaction and only partly reduces ROS generation. Moreover, the deubiquitinase cylindromatosis (CYLD) promotes BV6/TNFα-induced ROS generation and necrosome assembly even in the presence of BV6, as CYLD silencing attenuates these events. Genetic silencing of phosphoglycerate mutase 5 or dynamin-related protein 1 (Drp1) fails to protect against BV6/TNFα-induced cell death. By demonstrating that ROS are involved in regulating BV6/TNFα-induced necroptotic signaling, our study provides new insights into redox regulation of necroptosis.

The Opening of ATP-Sensitive K+ Channels Protects H9c2 Cardiac Cells Against the High Glucose-Induced Injury and Inflammation by Inhibiting the ROS-TLR4-Necroptosis Pathway

“…Taken together, our results clearly demonstrated that there is a link among ROS, TLR4 and RIP3, and that ROS mediates the HG-induced activation of TLR4 and necroptosis. Schenk et al [31] more recently showed that ROS regulate Smac mimetic/TNF-α-induced necroptosis signaling, which strengthens our findings that ROS plays a critical role in activation of TLR4 and necroptosis induced by HG in H9c2 cardiac cells. Next, our further studies revealed that NAC or TAK-242 or Nec-1 respectively attenuated the HG-induced cardiac injuries and inflammation, as indicated by an increase in cell viability, and a decrease in ROS generation, dissipation of MMP and the secretion levels of IL-1β as well as TNF-α.…”

“…Increasing evidence indicates that necroptosis is activated by several pathways, such as tumor necrosis factor-α (TNF-α) [26, 27], TLRs [28, 29] and ROS [21, 30]. Since HG has been shown to induce ROS generation, TNF-α and TLR4 expression as well as necroptosis, and there is a link between ROS, TNF-α and necroptosis in human FADD-deficient Jurkat cells [31], thus we speculated that ROS-TLR4-necroptosis pathway may be an important intracellular signaling mechanism which contributed to the HG-induced cardiac injury and inflammation. Furthermore, we explored whether the inhibition of this pathway contributes to the protective effect of K ATP channels against the HG-induced injury and inflammation in H9c2 cardiac cells.…”

Bax/Bak-independent mitochondrial depolarization and reactive oxygen species induction by sorafenib overcome resistance to apoptosis in renal cell carcinoma

“…It has been shown that, in FADD-deficient acute lymphoblastic leukemia cells, ROS induction is a critical regulator of necroptotic cell death induced by a Smac mimetic in combination with TNF␣. Consistent with the definition of necroptosis, this cell death is caspase-independent (46,47). In contrast, ROS-mediated cell death induced by sorafenib/ TRAIL is blocked by the caspase inhibitor Q-VD-OPh, indicating induction of apoptotic cell death.…”

Evolutionary divergence of the necroptosis effector MLKL

“…13,14 The relevance of the former is unclear because cardiolipin is believed to be exclusively mitochondrially localized, yet mitochondria and the PGAM5-Drp1 mitochondrial fragmentation pathway are not universally required for necroptosis. 5,20,[26][27][28] Here, we observed that the 4HB domains of mouse and frog MLKL, which kill MDFs, and human and chicken 4HB domains, which do not, could permeabilize membranes and exhibited a clear preference for plasma membrane over mitochondrial composition liposomes. Unexpectedly, full-length human, frog and chicken MLKL were more potent and rapid inducers of membrane permeabilization than the recombinant NTDs alone, suggesting a function for the pseudokinase domain in augmenting 4HB domain-mediated membrane permeabilization.…”