Myricetin ameliorates brain injury and neurological deficits via Nrf2 activation after experimental stroke in middle-aged rats

2016 ◽  
Vol 7 (6) ◽  
pp. 2624-2634 ◽  
Author(s):  
Shuangchan Wu ◽  
Yuan Yue ◽  
Anlin Peng ◽  
Lu Zhang ◽  
Jin Xiang ◽  
...  

The aim of our study was to investigate the protective effects and underlying mechanisms of myricetin, a bioactive food compound, on brain injury and neurological deficits after ischemic stroke.

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Jian Chen ◽  
Yun Xu

Background: Long non-coding RNAs (LncRNAs) are expressed at high levels in the brain in a variety of neuropathologic conditions, including stroke. However, the potential role of LncRNAs in ischemic stroke-associated microglial biological function and neurological injury remains largely unknown. Methods: Oxygen-glucose deprivation and transient middle cerebral artery occlusion (MCAO) in C57BL/6 mice were used as in vitro and in vivo ischemic stroke models. Microarray analysis was performed to explore the overall expression level changes of LncRNAs. Real-time polymerase chain reaction (RT-qPCR) was used to detect expression level of LncU90926 in brain, plasma and microglia. ShRNA-LncU90926 in lentivirus and microglia specific Adeno-associated virus (AAV) were used to knockdown LncU90926 in vitro and in vivo separately. Infarct volumes and neurological impairments were assessed by 2,3,5-triphenyltetrazolium chloride (TTC) staining, Neurological Severity Scores (NSS), rotarod test and grip strength respectively. Immunofluorescence staining and flow cytometry were performed to detect the number of neutrophils recruited to brain. RT-qPCR was used to detect the level of chemokines (CXCL, CCL2) and inflammatory mediators associated with neutrophils (MPO, MMP3 and TIMP1). Results: (1). LncU90926 was markedly up-regulated in the infarcted brain and plasma after MCAO. Both MCAO and OGD treatment induced remarkable up-regulation of LncU90926 in microglia. (2). LncU90926 knockdown definitely attenuated brain infarct size and neurological deficits after ischemic stroke. (3). LncU90926 knockdown in microglia reduced the number of neutrophils recruited to brain, and CXCL1 and CCL2 were down-regulated in both MCAO and OGD models. LncU90926 knockdown also induced reduction of MPO, MMP3 and TIMP1 in the infarcted brain. Conclusions: LncU90926 was up-regulated in microglia after experimental stroke, and aggravates ischemic brain injury through facilitating neutrophils infiltration via up-regulating microglial chemokine.


2020 ◽  
Vol 04 (01) ◽  
Author(s):  
Titiporn Mekrungruangwong ◽  
Pimpetch Kasetsuwan ◽  
Sheepsumon Viboolvorakul ◽  
Suthiluk Patumraj

2020 ◽  
Author(s):  
Leon Teo ◽  
Anthony G. Boghdadi ◽  
Jihane Homman-Ludiye ◽  
Iñaki Carril-Mundiñano ◽  
William C. Kwan ◽  
...  

AbstractInfants and adults respond differently to brain injuries. Specifically, improved neuronal sparing along with reduced astrogliosis and glial scarring often observed earlier in life, likely contributes to improved long-term outcomes. Understanding the underlying mechanisms could enable the recapitulation of neuroprotective effects, observed in infants, to benefit adult patients after brain injuries. We reveal that in primates, Eph/ ephrin signaling contributes to age-dependent reactive astrocyte behavior. Ephrin-A5 expression on astrocytes was more protracted in adults, whereas ephrin-A1 was associated only with infant astrocytes. Furthermore, ephrin-A5 exacerbated major hallmarks of astrocyte reactivity via EphA2 and EphA4 receptors, which was subsequently alleviated by ephrin-A1. Rather than suppressing reactivity, ephrin-A1 signaling shifted astrocytes towards GAP43+ neuroprotection, accounting for improved neuronal sparing in infants. Reintroducing ephrin-A1 after middle-aged ischemic stroke significantly attenuated glial scarring, improved neuronal sparing and preserved circuitry. Therefore, beneficial infant mechanisms can be recapitulated in adults to improve outcomes after CNS injuries.


2018 ◽  
Vol 48 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Qingqing Wang ◽  
Chengmei Lv ◽  
Yongxin Sun ◽  
Xu Han ◽  
Shan Wang ◽  
...  

Background/Aims: Ischemic stroke results in increased cerebral infarction, neurological deficits and neuroinflammation. The underlying mechanisms involving the anti-inflammatory and neuroprotective properties of α-Lipoic acid (α-LA) remain poorly understood. Herein, we investigated the potential role of α-LA in a middle cerebral artery occlusion (MCAO) rat model and an in vitro lipopolysaccharide (LPS)-induced microglia inflammation model. Methods: In the in vivo study, infarct volume was examined by TTC staining and Garcia score was used to evaluate neurologic recovery. The cytokines were evaluated by enzyme-linked immunosorbent assay, and protein expression of microglia phenotype and NF-κB were measured using western blot. In the in vitro study, the expressions of microglia M1/M2 phenotype were evaluated using qRT-PCR, and immunofluorescence staining was used to assess the nuclear translocation of NF-κB. Results: Both 20 mg/kg and 40 mg/kg of α-LA alleviated infarct size, brain edema, and neurological deficits. Furthermore, α-LA induced the polarization of microglia to the M2 phenotype, modulated the expression of IL-1β, IL-6, TNF-α and IL-10, and attenuated the activation of NF-κB after MCAO. α-LA inhibited the expression of M1 markers, increased activation of the M2 markers, and suppressed the nuclear translocation of NF-κB in LPS-stimulated BV2 microglia. Conclusions: α-LA improved neurological outcome in experimental stroke via modulating microglia M1/M2 polarization. The potential mechanism of α-LA might be mediated by inhibition of NF-κB activation via regulating phosphorylation and nuclear translocation of p65.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 330-330
Author(s):  
Anil Chauhan ◽  
Mohammad M Khan ◽  
Chintan Gandhi ◽  
Neelam Chauhan ◽  
Asgar Zaheer ◽  
...  

Abstract Abstract 330 Background: Fibronectin (FN) is a dimeric glycoprotein that plays an important role in several cellular processes, such as embryogenesis, malignancy, hemostasis, wound healing and maintenance of tissue integrity. FN is a ligand for many members of the integrin family (e.g. αIIbβ3, α5β1, α4β1, α9β1, αvβ3 and αvβ5) and also binds to thrombosis-related proteins including heparin, collagen and fibrin. FN generates protein diversity as a consequence of alternative processing of a single primary transcript. Two forms of FN exist; soluble plasma FN (pFN), which lacks the alternatively-spliced Extra Domain A (EDA); and insoluble cellular FN (cFN), which contains EDA. FN containing EDA (EDA+FN) is normally absent in plasma of human and mouse but EDA+FN has been found in patients with vascular injury secondary to vasculitis, sepsis, acute major trauma or ischemic stroke. We tested the hypothesis that elevated levels of plasma EDA+FN increase brain injury in an experimental model of ischemic stroke in mice. Model and Method: We used two genetically modified mouse strains: EDA+/+ mice contain optimized spliced sites at both splicing junctions of the EDA exon and constitutively express only EDA+FN, whereas EDA-/- mice contain an EDA-null allele of the EDA exon and express only FN lacking EDA. Control EDAwt/wt mice contain the wild-type FN allele. Transient focal cerebral ischemia was induced by 60 minutes of occlusion of the right middle cerebral artery with a 7.0 siliconized filament in male mice (8-10 weeks in age). Mice were anesthetized with 1–1.5% isoflurane mixed with medical air. Body temperature was maintained at 37°C ± 1.0 using a heating pad. Laser Doppler flowmetry was used to confirm induction of ischemia and reperfusion. At 23 hours after MCAO, mice were evaluated for neurological deficits as a functional outcome and were sacrificed for quantification of infarct volume. For morphometric measurement eight 1 mm coronal sections were stained with 2% triphenyl-2, 3, 4-tetrazolium-chloride (TTC). Sections were digitalized and infarct areas were measured blindly using NIS elements. Result: In EDA+/+ mice the percentage of infarct volume (mean ± SEM: 37.25 ± 4.11, n= 12,) in the ipsilateral (ischemic) hemisphere was increased by approximately two-fold compared to EDA wt/wt mice (mean ± SEM: 22.33 ± 3.39, n=11; P< 0.05, ANOVA) or EDA-/- mice (mean ± SEM: 21.72 ± 2.94, n=9). Regional cerebral blood flow during ischemia was not different among groups as assessed by laser Doppler flowmetry. The percentage increase in infarct volume in the EDA+/+ mice correlated well with severe neurological deficits (motor-deficit assessed by a four-point neurological score scale) compared to EDA wt/wt or EDA-/- mice. Because both thrombosis and inflammation contributes to brain injury during ischemic stroke, we investigated the time to form an occlusive thrombus in ferric-chloride carotid artery injury model by intravital microscopy. EDA+/+ mice demonstrated significantly faster time to occlusion (mean ± SEM: 12.35 ± 1.51 n=12,) compared to EDAwt/wt (Mean ± SEM: 17.27 ± 1.72 min, n=13, P<0.05, ANOVA) or EDA-/- (Mean ± SEM: 15.61 ± 1.76, n=11) mice. Additionally, the inflammatory response in the ischemic region was increased by two fold in EDA+/+ mice compared to EDA wt/wt and EDA-/- mice as sensed by myeloperoxidase activity and immunohistochemical analysis of neutrophils. Conclusion: EDA-containing FN is pro-thrombotic and pro-inflammatory, and aggravates ischemic brain injury in an experimental model of stroke in mice. The presence of EDA+FN in plasma may be a risk factor for vascular injury secondary to ischemic stroke. Disclosures: No relevant conflicts of interest to declare.


2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Zhongjun Chen ◽  
Tieping Fan ◽  
Xusheng Zhao ◽  
Zhichen Zhang

Abstract Objectives Studies have widely explored in the filed of ischemic stroke (IS) with their focus on transcription factors. However, few studies have pivoted on sex determining region Y-box 2 (SOX2) in IS. Thus, this study is launched to figure out the mechanisms of SOX2 in IS. Methods Rat middle cerebral artery occlusion (MCAO) was established as a stroke model. MCAO rats were injected with depleted SOX2 or long non-coding RNA plasmacytoma variant translocation 1 (PVT1) to explore their roles in neurological deficits, cerebral water content, neuron survival, apoptosis and oxidative stress. The relationship among SOX2, PVT1, microRNA (miR)-24-3p and signal transducer and activator of transcription 3 (STAT3) was verified by a series of experiments. Results SOX2, PVT1 and STAT3 were highly expressed while miR-24-3p was poorly expressed in cerebral cortex tissues of MCAO rats. Depleted SOX2 or PVT1 alleviated brain injury in MCAO rats as reflected by neuronal apoptosis and oxidative stress restriction, brain water content reduction, and neurological deficit and neuron survival improvements. Overexpression of PVT1 functioned oppositely. Restored miR-24-3p abolished PVT1 overexpression-induced brain injury in MCAO rats. SOX2 directly promoted PVT1 expression and further increased STAT3 by sponging miR-24-3p. Conclusion This study presents that depleting SOX2 improves IS via PVT1/miR-24-3p/STAT3 axis which may broaden our knowledge about the mechanisms of SOX2/PVT1/miR-24-3p/STAT3 axis and provide a reference of therapy for IS.


2021 ◽  
Vol 15 ◽  
Author(s):  
Yunwei Shi ◽  
Xinyi Chen ◽  
Jiaxing Liu ◽  
Xingjuan Fan ◽  
Ying Jin ◽  
...  

Inflammatory response contributes to brain injury after ischemia and reperfusion (I/R). Our previous literature has shown isoquercetin plays an important role in protecting against cerebral I/R injury. The present study was conducted to further investigate the effect of isoquercetin on inflammation-induced neuronal injury in I/R rats with the involvement of cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) and inhibitor of NF-κB (I-κB)/nuclear factor-kappa B (NF-κB) signaling pathway mediated by Toll-like receptor 4 (TLR4) and C5a receptor 1 (C5aR1). In vivo middle cerebral artery occlusion and reperfusion (MCAO/R) rat model and in vitro oxygen-glucose deprivation and reperfusion (OGD/R) neuron model were used. MCAO/R induced neurological deficits, cell apoptosis, and release of cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in ischemic brain in rats. Simultaneously, the expression of TLR4 and C5aR1 was significantly up-regulated in both MCAO/R rats and OGD/R neurons, accompanied with the inhibition of cAMP/PKA signaling and activation of I-κB/NF-κB signaling in the cortex of MCAO/R rats. Over-expression of C5aR1 in neurons induced decrease of cell viability, exerting similar effects with OGD/R injury. Isoquercetin acted as a neuroprotective agent against I/R brain injury to suppress inflammatory response and improve cell recovery by inhibiting TLR4 and C5aR1 expression, promoting cAMP/PKA activation, and inhibiting I-κB/NF-κB activation and Caspase 3 expression. TLR4 and C5aR1 contributed to inflammation and apoptosis via activating cAMP/PKA/I-κB/NF-κB signaling during cerebral I/R, suggesting that this signaling pathway may be a potent therapeutic target in ischemic stroke. Isoquercetin was identified as a neuroprotective agent, which maybe a promising therapeutic agent used for the treatment of ischemic stroke and related diseases.


Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Xinxin Yang ◽  
Kai Liu ◽  
Jun Chen ◽  
Ke-Jie Yin

MicroRNAs (miRs) are small endogenous RNA molecules that repress gene translation by hybridizing to 3’-UTRs of mRNAs. Accumulating evidence has shown that miRs play a critical regulatory role in the pathogenesis of ischemic stroke. MiR-15a and miR-16-1 are two highly conserved miRs, which act similarly by binding to their common mRNA targets, thus forming both a structural and functional cluster. Dysregulated plasma levels of miR-15a/16-1 have been reported in stroke patients. Inhibition of miR-15a has been shown to protect against myocardial infarction and selected by pharmaceutical companies as one of the most attractive miR-based therapeutics. Up to now, the essential role and therapeutic potential of the miR-15a/16-1 cluster in ischemic stroke are poorly understood. In this study, adult male miR-15a/16-1 knockout and wildtype mice were subjected to 45 min of middle cerebral artery occlusion (MCAO) and 72h of reperfusion. In a separate experiment, miR-15a/16-1 specific inhibitor (antagomir, 30 pmol/g) was injected into tail vein of stroke mice and the animals were allowed to survive for 72h. The neurological scores, brain infarct volume, and edema content were then evaluated and analyzed. To explore the underlying mechanism, inflammatory factors were measured by qPCR or ELISA and anti-apoptotic proteins were examined by western blotting. We found that genetic deletion of miR-15a/16-1 or intravenous delivery of miR-15a/16-1 antagomir significantly reduced cerebral infarct size, decreased brain edema and improved neurological outcomes in stroke mice. Mechanistically, treatment of miR-15a/16-1 antagomir significantly ameliorated the expression of several key inflammatory factors and increased the Bcl-2 and Bcl-w levels in the ischemic brain regions. These results demonstrated that pharmacological inhibition of miR-15a/16-1 reduces ischemic brain injury via both anti-apoptotic and anti-inflammatory mechanisms and the miR-15a/16-1 cluster is a novel therapeutic target for ischemic stroke.


2002 ◽  
Vol 32 (2) ◽  
pp. 85-89 ◽  
Author(s):  
Y. X. Shen ◽  
S. Y. Xu ◽  
W. Wei ◽  
X. X. Sun ◽  
L. H. Liu ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Changmeng Cui ◽  
Sixin Song ◽  
Jianzhong Cui ◽  
Yan Feng ◽  
Junling Gao ◽  
...  

Traumatic brain injury (TBI) is a worldwide phenomenon which results in significant neurological and cognitive deficits in humans. Vitamin D (VD) is implicated as a therapeutic strategy for various neurological diseases now. Recently, inhibition of the NADPH oxidase (NOX2) was reported to protect against oxidative stress (ROS) production. However, whether alterations in NOX2expression and NOX activity are associated with calcitriol (active metabolite of VD) treatment following TBI remains unclear. In the present study, rats were randomly assigned to the sham, TBI, and calcitriol-treated groups. Calcitriol was administered intraperitoneally (2 μg/kg) at 30 min, 24 h, and 48 h after TBI insult. We observed that calcitriol treatment alleviated neurobehavioral deficits and brain edema following TBI. At the molecular levels, administration of calcitriol activated the expression of VDR and downregulated NOX2as well as suppressed apoptosis cell rate in the hippocampus CA1 region of TBI rats. In conclusion, our findings indicate that the protective effects of calcitriol may be related to the modulation of NADPH oxidase and thereby ultimately inhibited the progression of apoptosis. Calcitriol may be promising as a protective intervention following TBI, and more study is warranted for its clinical testing in the future.


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