Activation of Canonical Notch Signaling Pathway Is Involved in the Ischemic Tolerance Induced by Sevoflurane Preconditioning in Mice

Article · August 2012with3 Reads
DOI: 10.1097/ALN.0b013e31826cb469 · Source: PubMed
: A wealth of evidence has demonstrated that sevoflurane preconditioning induces brain ischemic tolerance, but the mechanism remains poorly understood. This study was designed to investigate the role of canonical Notch signaling in the neuroprotection induced by sevoflurane preconditioning in a mouse model. : C57BL/6 mice were pretreated with 1-h sevoflurane exposure at a dose of 2.5% for 5 consecutive days. Twenty-four hours after the last exposure, all mice were subjected to focal cerebral ischemia by right middle cerebral artery occlusion for 60 min. Neurobehavioral scores, brain infarct volumes, and cellular apoptosis were determined at 72 h after reperfusion (n = 10 per group). The activation of Notch signaling was evaluated (n = 5 per group), and its role in ischemic tolerance was assessed by intraperitoneal administration of γ-secretase inhibitor DAPT (100 mg/kg, n = 10 per group) and conditional Notch-RBP-J knockout technique (n = 8 per group). : Sevoflurane preconditioning reduced brain infarct volumes (42.5%), improved neurologic outcomes (P < 0.01 vs. control), and attenuated neuronal cell apoptosis (cells positive for terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick-end labeling reduced to 21.2%). The expression of Notch1 intracellular domain (1.35 folds) and the transcriptions of Hes1 (1.95 times) and Hes5 (1.48 times) were up-regulated. DAPT augmented the brain infarcts (1.64-fold) and decreased neurologic scores (P = 0.43 vs. sevoflurane) in sevoflurane-preconditioned mice. Brain infarct volumes, neurobehavioral scores, and apoptotic cell numbers showed no significance between Notch knockout mice with sevoflurane preconditioning and wild-type mice without preconditioning. : Sevoflurane preconditioning-induced protective effects against transient cerebral ischemic injuries are mediated by the activation of canonical Notch signaling pathway in mice.
    • MCAO was performed as previously described [17]. Cerebral blood flow was monitored using laser Doppler flowmetry (PeriFlux 5000; Perimed AB, Järfälla, Sweden).
    [Show abstract] [Hide abstract] ABSTRACT: Nearly all clinical trials that have attempted to develop effective strategies against ischemic stroke have failed, excluding those for thrombolysis, and most of these trials focused only on preventing neuronal loss. However, astrocytes have gradually become a target for neuroprotection in stroke. In previous studies, we showed that the newly identified molecular N-myc downstream-regulated gene 2 (Ndrg2) is specifically expressed in astrocytes in the brain and involved in some neurodegenerative diseases. However, the role of NDRG2 in ischemic stroke remained unclear. In this study, we investigated the role of NDRG2 in middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia and in oxygen–glucose deprivation (OGD)-induced cellular apoptosis in the M1800 astrocyte cell line. NDRG2 mRNA and protein expression began to increase at 6 and 2 h after reperfusion and peaked at 24 h in the ischemic penumbra and in M1800 cells, as detected by RT-PCR and Western blotting. Double immunofluorescence staining showed that the number of apoptotic cells increased as the NDRG2-positive signal increased and that the NDRG2 signal was sometimes co-localized with TUNEL-positive cells and translocated from the cytoplasm to the nucleus in both the ischemic penumbra and the M1800 cells. Using a lentivirus, we successfully constructed two stable astrocytic cell lines in which NDRG2 expression was significantly up- or down-regulated. NDRG2 silencing had a proliferative effect and reduced the percentage of apoptotic cells, reactive oxygen species (ROS) production, and cleaved Caspase-3 protein expression following OGD, whereas NDRG2 over-expression had the opposite effects. In conclusion, NDRG2 is involved in astrocyte apoptosis following ischemic–hypoxic injury, and inhibiting NDRG2 expression significantly reduces ROS production and astrocyte apoptosis. These findings provide insight into the role of NDRG2 in ischemic–hypoxic injury and provide potential targets for future clinical therapies for stroke.
    Article · May 2016
    • I/R) It is still controversial whether the activated canonical Notch signaling is beneficial to the ischemic cerebral tissues. Many researchers have found that the activation of Notch signaling was involved in the ischemic tolerance induced by inhalation anesthetics preconditioning (Zhang et al. 2014; Yang et al. 2012). However, other reports was consistent with the opinion that Notch signaling can induce neuronal cell death (Arumugam et al. 2011).
    [Show abstract] [Hide abstract] ABSTRACT: We have reported electroacupuncture (EA) pretreatment induced the tolerance against focal cerebral ischemia through activation of canonical Notch pathway. However, the underlying mechanisms have not been fully understood. Evidences suggest that up-regulation of hypoxia inducible factor-1α (HIF-1α) contributes to neuroprotection against ischemia which could interact with Notch signaling pathway in this process. Therefore, the current study is to test that up-regulation of HIF-1α associated with Notch pathway contributes to the neuroprotection of EA pretreatment. Sprague–Dawley rats were treated with EA at the acupoint “Baihui (GV 20)” 30 min per day for successive 5 days before MCAO. HIF-1α levels were measured before and after reperfusion. Then, HIF-1α antagonist 2ME2 and γ-secretase inhibitor MW167 were used. Neurologic deficit scores, infarction volumes, neuronal apoptosis, and Bcl2/Bax were evaluated. HIF-1α and Notch1 intracellular domain (NICD) were assessed. The results showed EA pretreatment enhanced the neuronal expression of HIF-1α, reduced infarct volume, improved neurological outcome, inhibited neuronal apoptosis, up-regulated expression of Bcl-2, and down-regulated expression of Bax after reperfusion in the penumbra, while the beneficial effects were attenuated by 2ME2. Furthermore, intraventricular injection with MW167 efficiently suppressed both up-regulation of NICD and HIF-1α after reperfusion. However, administration with 2ME2 could only decrease the expression of HIF-1α in the penumbra. In conclusion, EA pretreatment exerts neuroprotection against ischemic injury through Notch pathway-mediated up-regulation of HIF-1α.
    Full-text · Article · May 2015
    • To identify transcriptional factor upon Chip-seq gene profile, we performed ChEA analysis in upregulated DEGs both at T0 and T1. Results suggested that NOTCH1 remarkably regulated overexpressed DEGs at T1 but not at T0. Recent studies have shown that NOTCH1 assumed a fundamental role in the mechanisms of cerebral ischemia injury [38] through eliciting protective effects against ischemia injury by decreasing neuronal apoptosis in mice [39]. IPC-induced NOTCH1 signaling could activate the endogenous neuroprotective components and decrease the ischemic-reperfusion injury at the early phase after stroke [40].
    [Show abstract] [Hide abstract] ABSTRACT: Background Ischemia preconditioning (IPC) has been proved as a powerful method of protecting tissues against ischemia reperfusion insults. We aimed to elucidate the mechanism of IPC in ischemia reperfused tissues.MethodsGSE21164 containing 16 muscle biopsies taken from the operative knee of four IPC-treated patients and four control at the onset of surgery (T¿=¿0) and 1 h into surgery (T¿=¿1) undergoing primary total knee arthroplasty was downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between IPC group and control were screened with Limma package in R language. KEGG pathway enrichment analysis was performed by the DAVID online tool. Meanwhile, potential regulatory microRNAs (miRNAs) for downregulated DEGs and targets of transcription factors for upregulated DEGs were screened out. Based on the above DEGs, protein-protein interaction (PPI) networks were constructed by the STRING software.ResultsSignificantly upregulated DEGs at T1 were mainly enriched in asthma and p53 signaling pathway. Meanwhile, significantly enriched transcriptional factor NOTCH1 at T1 and GABP at T0 were obtained. Moreover, miRNA analysis showed that targets of miR141/200a were enriched in downregulated DEGs both at T0 and T1. Mostly, RPA1 and JAK2 in PPI network at T1 were with higher degree.Conclusions In our study, obtained DEGs, regulatory transcriptional factors, and miRNA might play a vital role in the protection of ischemia reperfusion injury. This finding will provide a deeper understanding to the mechanism of IPC.
    Full-text · Article · Dec 2014
    • The mice were fasted overnight with free access to tap water before surgery. Cerebral ischemia was induced by MCAO as previously described 22. The mice were then intraperitoneally anesthetized with pentobarbital sodium (60 mg/kg).
    [Show abstract] [Hide abstract] ABSTRACT: Stroke has severe consequences in postmenopausal women. As replacement therapy of estrogen have various adverse effects and the undermined outcomes. Genistein, a natural phytoestrogen, has been suggested to be a potential neuroprotective agent for such stroke patients. However, the role of genistein and its underlying mechanism in ovariectomized mice has not yet been evaluated. In the present study, ovariectomized mice were treated with genistein (10 mg/kg) or vehicle daily for two weeks before developing transient cerebral ischemia (middle cerebral artery occlusion). The neurological manifestation was evaluated, and infarct volumes were demonstrated by 2,3,5-triphenyltetrazolium chloride staining at 24 h after reperfusion. In addition, phosphorylation of extracellular signal-regulated kinase (ERK) was detected by Western blotting and immunofluorescence staining, and cellular apoptosis was evaluated in the ischemic penumbra. We found that treatment with genistein reduced infarct volumes, improved neurological outcomes and attenuated cellular apoptosis at 24 h after reperfusion. ERK1/2 showed increased phosphorylation by genistein treatment after reperfusion, and an ERK1/2 inhibitor U0126 abolished this protective effect of genistein in terms of infarct volumes, neurological scores and cellular apoptosis. Our findings indicate that treatment with genistein can reduce the severity of subsequent stroke episodes, and that this beneficial function is associated with ERK activation.
    Full-text · Article · Apr 2014
    • In addition, a recent study also shows that Notch 3 À/À mice developed ischemic lesions approximately twice as large as those seen in WT or heterozygous (Notch 3 +/À ) male mice (Arboleda-Velasquez et al., 2008). Very recent studies show that the activation of Notch signaling is involved in the ischemic tolerance (Yang et al., 2012; Zhao et al., 2012). The reason for the discrepancy between these studies is unknown, but a possible explanation for these apparently contradicting results may be due to different animal strains and animal models of stroke, and the different Notch1 signaling inhibitor used in these studies, as c-secretase inhibitors may not only involve in Notch1 signaling, but also other signaling transduction pathways, which may play a role in neuroprotection in the ischemic brain.
    [Show abstract] [Hide abstract] ABSTRACT: Neurogenesis diminishes with aging and ischemia-induced neurogenesis also occurs, but reduced in aged brain. Currently, the cellular and molecular pathways mediating these effects remain largely unknown. Our previous study has shown that Notch1 signaling regulates neurogenesis in subventricular zone (SVZ) of young-adult brain after focal ischemia, but whether a similar effect occurs in aged normal and ischemic animals is unknown. Here, we used normal and ischemic aged rat brains to investigate whether Nortch1 signaling was involved in the reduction of neurogenesis in response to aging and modulates neurogenesis in aged brains after focal ischemia. By Western blot, we found that Nortch1 and Jagged1 expression in the SVZ of aged brain was significantly reduced compared with young-adult brain. Consistently, the activated form of Notch1(Notch intracellular domain;NICD) expression was also declined. Immunohistochemistry confirmed that expression and activation of Notch1 signaling in the SVZ of aged brain were reduced. Double or triple immunostaining showed that that Notch1 was mainly expressed in DCX-positive cells, whereas Jagged1 was predominantly expressed in astroglial cells in the SVZ of normal aged rat brain. In addition, disruption or activation of Notch1 signaling altered the number of proliferating cells labeled by bromodeoxyuridine (BrdU) and doublecortin (DCX) in the SVZ of aged brain. Moreover, ischemia-induced cell proliferation in the SVZ of aged brain was enhanced by activating the Notch1 pathway, and was suppressed by inhibiting the Notch1 signaling. Reduced infarct volume and improved motor deficits were also observed in Notch1 activator-treated aged ischemic rats. Our data suggest that Notch1 signaling modulates the SVZ neurogenesis in aged brain in normal and ischemic conditions. This article is protected by copyright. All rights reserved.
    Article · Jul 2013
  • [Show abstract] [Hide abstract] ABSTRACT: We provide a review of both clinical and basic science literature from 2012 relevant to care of the patient with neurological disease. Our review addresses the following major areas: general neurosurgical procedures, stroke, traumatic brain injury, spine surgery, anesthetic neurotoxicity, neuroprotective strategies, electrophysiological monitoring, history, and graduate medical education. We have focused on research describing new and innovative concepts and recurring themes. This review is intended to be of interest to those working in the clinical arena and also to neuroscientists.
    Article · Apr 2012
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