scholarly journals Sequential activation of necroptosis and apoptosis cooperates to mediate vascular and neural pathology in stroke

2020 ◽  
Vol 117 (9) ◽  
pp. 4959-4970 ◽  
Author(s):  
Masanori Gomi Naito ◽  
Daichao Xu ◽  
Palak Amin ◽  
Jinwoo Lee ◽  
Huibing Wang ◽  
...  

Apoptosis and necroptosis are two regulated cell death mechanisms; however, the interaction between these cell death pathways in vivo is unclear. Here we used cerebral ischemia/reperfusion as a model to investigate the interaction between apoptosis and necroptosis. We show that the activation of RIPK1 sequentially promotes necroptosis followed by apoptosis in a temporally specific manner. Cerebral ischemia/reperfusion insult rapidly activates necroptosis to promote cerebral hemorrhage and neuroinflammation.Ripk3deficiency reduces cerebral hemorrhage and delays the onset of neural damage mediated by inflammation. Reduced cerebral perfusion resulting from arterial occlusion promotes the degradation of TAK1, a suppressor of RIPK1, and the transition from necroptosis to apoptosis. Conditional knockout of TAK1 in microglial/infiltrated macrophages and neuronal lineages sensitizes to ischemic infarction by promoting apoptosis. Taken together, our results demonstrate the critical role of necroptosis in mediating neurovascular damage and hypoperfusion-induced TAK1 loss, which subsequently promotes apoptosis and cerebral pathology in stroke and neurodegeneration.

2021 ◽  
Vol 12 (1) ◽  
pp. 210-217
Author(s):  
Yibiao Wang ◽  
Min Xu

Abstract Background This study aimed to explore the role of miR-380-5p in cerebral ischemia/reperfusion (CIR) injury-induced neuronal cell death and the potential signaling pathway involved. Methodology Human neuroblastoma cell line SH-SY5Y cells were used in this study. Oxygen and glucose deprivation/reperfusion (OGD/R) model was used to mimic ischemia/reperfusion injury. CCK-8 assay and flow cytometry were used to examine cell survival. Quantitative real time PCR (RT-qPCR) assay and Western blotting were used to measure the change of RNA and protein expression, respectively. TargetScan and Luciferase assay was used to confirm the target of miR-380-5p. Malondialdehyde (MDA) superoxide dismutase (SOD) and glutathione peroxidase (GSHPx) were measured using commercial kits. Results miR-380-5p was downregulated in SH-SY5Y cells after OGD/R. Cell viability was increased by miR-380-5p, while cell apoptosis was reduced by miR-380-5p mimics. MDA was reduced by miR-380-5p mimics, while SOD and GSHPx were increased by miR-380-5p. Results of TargetScan and luciferase assay have showed that BACH1 is the direct target of miR-380-5p. Expression of NRF2 was upregulated after OGD/R, but was not affected by miR-380-5p. mRNA expression of HO-1 and NQO1 and ARE activity were increased by miR-380-5p. Overexpression of BACH1 reversed the antioxidant and neuroprotective effects of miR-380-5p. Conclusion miR-380-5p inhibited cell death induced by CIR injury through target BACH1 which also facilitated the activation of NRF2, indicating the antioxidant and neuroprotective effects of miR-380-5p.


2021 ◽  
Author(s):  
Weifeng Shan ◽  
Huifeng Ge ◽  
Bingquan Chen ◽  
Linger Huang ◽  
Shaojun Zhu ◽  
...  

Abstract MiR-499a-5p was significantly down-regulated in degenerative tissues and correlated with apoptosis. Nonetheless, the biological function of miR-499a-5p in acute ischemic stroke has been still unclear. In this study, we found the plasma levels of miR-499a-5p were significantly down-regulated in 64 ischemic stroke patients and negatively correlated with the National Institutes of Health Stroke Scale score. Then, we constructed cerebral ischemia/reperfusion (I/R) injury in rats after middle cerebral artery occlusion and subsequent reperfusion and oxygen-glucose deprivation and reoxygenation (OGD/R) treated SH-SY5Y cell model. Transfection with miR-499a-5p mimic was accomplished by intracerebroventricular injection in the in vivo I/R injury model. We further found miR-499a-5p overexpression decreased infarct volumes and cell apoptosis in the in vivo I/R stroke model using TTC and TUNEL staining. PDCD4 was a direct target of miR-499a-5p by luciferase report assay and western blotting. Knockdown of PDCD4 reduced the infarct damage and cortical neuron apoptosis caused by I/R injury. MiR-499a-5p exerted neuroprotective roles mainly through inhibiting PDCD4-mediated apoptosis by CCK-8 assay, LDH release assay and flow cytometry analysis. These findings suggest that miR-499a-5p might represent a novel target that regulates brain injury by inhibiting PDCD4-mediating apoptosis.


2019 ◽  
Vol 10 (9) ◽  
Author(s):  
Chengyuan Tang ◽  
Hailong Han ◽  
Zhiwen Liu ◽  
Yuxue Liu ◽  
Lijun Yin ◽  
...  

Abstract Acute kidney injury (AKI) is a syndrome of abrupt loss of renal functions. The underlying pathological mechanisms of AKI remain largely unknown. BCL2-interacting protein 3 (BNIP3) has dual functions of regulating cell death and mitophagy, but its pathophysiological role in AKI remains unclear. Here, we demonstrated an increase of BNIP3 expression in cultured renal proximal tubular epithelial cells following oxygen-glucose deprivation-reperfusion (OGD-R) and in renal tubules after renal ischemia–reperfusion (IR)-induced injury in mice. Functionally, silencing Bnip3 by specific short hairpin RNAs in cultured renal tubular cells reduced OGD-R-induced mitophagy, and potentiated OGD-R-induced cell death. In vivo, Bnip3 knockout worsened renal IR injury, as manifested by more severe renal dysfunction and tissue injury. We further showed that Bnip3 knockout reduced mitophagy, which resulted in the accumulation of damaged mitochondria, increased production of reactive oxygen species, and enhanced cell death and inflammatory response in kidneys following renal IR. Taken together, these findings suggest that BNIP3-mediated mitophagy has a critical role in mitochondrial quality control and tubular cell survival during AKI.


2000 ◽  
Vol 20 (10) ◽  
pp. 1467-1473 ◽  
Author(s):  
Jeffrey N. Keller ◽  
Feng F. Huang ◽  
Hong Zhu ◽  
Jin Yu ◽  
Ye-Shih Ho ◽  
...  

Numerous studies indicate a role for oxidative stress in the neuronal degeneration and cell death that occur during ischemia–reperfusion injury. Recent data suggest that inhibition of the proteasome may be a means by which oxidative stress mediates neuronal cell death. In the current study, the authors demonstrate that there is a time-dependent decrease in proteasome activity, which is not associated with decreased expression of proteasome subunits, after cerebral ischemia–reperfusion injury. To determine the role of oxidative stress in mediating proteasome inhibition, ischemia–reperfusion studies were conducted in mice that either overexpressed the antioxidant enzyme glutathione peroxidase [GPX 1(+)], or were devoid of glutathione peroxidase activity (GPX −/−). After ischemia–reperfusion, GPX 1(+) mice displayed decreased infarct size, attenuated neurologic impairment, and reduced levels of proteasome inhibition compared with either GPX −/− or wild type mice. In addition, GPX 1(+) mice displayed lower levels of 4-hydroxynonenal-modified proteasome subunits after ischemia–reperfusion injury. Together, these data indicate that proteasome inhibition occurs during cerebral ischemia–reperfusion injury and is mediated, at least in part, by oxidative stress.


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