Abstract
Necroptosis, a recently discovered form of non-apoptotic programmed cell death, can be implicated in many pathological conditions including neuronal cell death. Moreover, an inhibition of this process by necrostatin-1 (Nec-1) has been shown to be neuroprotective in in vitro and in vivo models of cerebral ischemia. However, the involvement of this type of cell death in oxidative stress–induced neuronal cell damage is less recognized. Therefore, we tested the effects of Nec-1, an inhibitor of necroptosis, in the model of hydrogen peroxide (H2O2)-induced cell damage in human neuroblastoma SH-SY5Y and murine hippocampal HT-22 cell lines. The data showed that Nec-1 (10–40 μM) attenuated the cell death induced by H2O2 in undifferentiated (UN-) and neuronal differentiated (RA-) SH-SY5Y cells with a higher efficacy in the former cell type. Moreover, Nec-1 partially reduced cell damage induced by 6-hydroxydopamine in UN- and RA-SH-SY5Y cells. The protective effect of Nec-1 was of similar magnitude as the effect of a caspase-3 inhibitor in both cell phenotypes and this effect were not potentiated after combined treatment. Furthermore, the non-specific apoptosis and necroptosis inhibitor curcumin augmented the beneficial effect of Nec-1 against H2O2-evoked cell damage albeit only in RA-SH-SY5Y cells. Next, it was found that the mechanisms of neuroprotective effect of Nec-1 against H2O2-induced cell damage in SH-SY5Y cells involved the inhibition of lysosomal protease, cathepsin D, but not caspase-3 or calpain activities. In HT-22 cells, Nec-1 was protective in two models of oxidative stress (H2O2 and glutamate) and that effect was blocked by a caspase inhibitor. Our data showed neuroprotective effects of the necroptosis inhibitor, Nec-1, against oxidative stress–induced cell damage and pointed to involvement of cathepsin D inhibition in the mechanism of its action. Moreover, a cell type–specific interplay between necroptosis and apoptosis has been demonstrated.
Highlights
Based on our previous findings where we showed an engagement of caspase-3 independent mechanism engaging apoptosis inducing factor (AIF) translocation in the model of H2O2-evoked cell damage in UN-SH-SY5Y cells (Jantas et al 2015a), and on the other hand, there are data showing a connection between AIF translocation and necroptosis induction (Bollino et al 2015; Ji et al 2011; Xu et al 2010b, 2016), we decided to study the effect of Nec-1 (20 μM) on cytosolic AIF protein level
We found that 30 min pre-treatment of the SH-SY5Y cells with Nec-1 in a wide range of micromolar concentrations attenuated but not totally prevented toxic effects of H2O2 or 6-OHDA suggesting that necroptosis could be only one of several activated cell death signaling pathways following exposure of the cells to the above-mentioned toxic agents
It was reported that caspase-3-dependent apoptosis and necrosis were involved in the mechanism of H2O2 neurotoxicity (Chwastek et al 2017; Cole and Perez-Polo 2002; Jantas et al 2015a; Fig. 6 The effect of combined treatment with necrostatin-1 (Nec-1) and caspase-3 inhibitor (Ac-DEVD-CHO) (a, b) or Nec-1 and curcumin (Curc) (c, d) against the 6-OHDA-induced cell damage in UN- (a, c) and retinoic acid (RA)- (b, d) SH-SY5Y cells
Summary
Necroptosis, a form of non-apoptotic programmed cell death, was shown to be activated in various models of acute (stroke, Neurotox Res (2020) 37:525–542 formation of the necrosome complex (Degterev et al 2014; Zhao et al 2015).In recent years, various inhibitors of necroptosis have been experimentally tested in relation to various human pathologies and used for mechanistic investigation of this process (Degterev et al 2005, 2008, 2013; Delehouzé et al 2017; Do et al 2017; Li et al, 2018; Xie et al 2013). It should be noted that the protective effect of Nec-1 in the above studies was only partial, suggesting the participation of other than necroptosis cell death programs which can vary depending on the type of neuronal injury as has already been shown by in vivo (ischemia, traumatic brain injury, spinal cord injury, retina injury) and in vitro studies (e.g., Al-, iron-, 6-OHDA-, or β-amyloidinduced neurotoxicity) (Askalan et al 2015; Chinskey et al 2014; Dai et al 2013; Dong et al 2012; Liu et al 2014; Rosenbaum et al 2010; Qinli et al 2013; Wu et al 2015; Xu et al 2010a; Zhang et al 2008). A potential synergistic effect has been proposed after combined treatment with various cell death–specific inhibitors (Koshinuma et al 2014; Xu et al 2010a)
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