Neuroprotective Effects of Guanosine in Ischemic Stroke—Small Steps towards Effective Therapy

Guanosine (Guo) is a nucleotide metabolite that acts as a potent neuromodulator with neurotrophic and regenerative properties in neurological disorders. Under brain ischemia or trauma, Guo is released to the extracellular milieu and its concentration substantially raises. In vitro studies on brain tissue slices or cell lines subjected to ischemic conditions demonstrated that Guo counteracts destructive events that occur during ischemic conditions, e.g., glutaminergic excitotoxicity, reactive oxygen and nitrogen species production. Moreover, Guo mitigates neuroinflammation and regulates post-translational processing. Guo asserts its neuroprotective effects via interplay with adenosine receptors, potassium channels, and excitatory amino acid transporters. Subsequently, guanosine activates several prosurvival molecular pathways including PI3K/Akt (PI3K) and MEK/ERK. Due to systemic degradation, the half-life of exogenous Guo is relatively low, thus creating difficulty regarding adequate exogenous Guo distribution. Nevertheless, in vivo studies performed on ischemic stroke rodent models provide promising results presenting a sustained decrease in infarct volume, improved neurological outcome, decrease in proinflammatory events, and stimulation of neuroregeneration through the release of neurotrophic factors. In this comprehensive review, we discuss molecular signaling related to Guo protection against brain ischemia. We present recent advances, limitations, and prospects in exogenous guanosine therapy in the context of ischemic stroke.

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The Neuroprotective Effects of Insulin-Like Growth Factor 1 via the Hippo/YAP Signaling Pathway is Mediated by the PI3K/AKT Pathway Following Cerebral Ischemia-Reperfusion Injury

10.21203/rs.3.rs-187237/v1 ◽

2021 ◽

Author(s):

Pian Gong ◽

Yichun Zou ◽

Wei Zhang ◽

Qi Tian ◽

Shoumeng Han ◽

...

Keyword(s):

Ischemic Stroke ◽

Growth Factor ◽

Signaling Pathway ◽

Neuronal Death ◽

Infarct Volume ◽

Akt Signaling ◽

Akt Signaling Pathway ◽

Neuroprotective Effects

Abstract Insulin-like growth factor 1 (IGF-1) exhibits neuroprotective properties, such as vasodilatory and anti-inflammatory effects following ischemic stroke. However, the specific molecular mechanisms of action of IGF-1 following ischemic stroke remain elusive. We wanted to explore whether IGF-1 regulates Hippo/YAP signaling pathway, potentially via activation of the PI3K/AKT signaling pathway to exert its neuroprotective effects following ischemic stroke. In the in vitro study, we used oxygen–glucose deprivation to injure cultured PC12 and SH-5YSY cells, and cortical primary neurons. Cell viability was measured using CCK-8 assay. For the in vivo analyses, Sprague–Dawley rats were subjected to middle cerebral artery occlusion; neurological function was assessed using the neurological deficit score; infarct volume was measured using triphenyltetrazolium chloride staining, and neuronal death and apoptosis was evaluated by TUNEL staining, H&E staining and Nissl staining. Western blot was used to measure the levels of YAP/TAZ, PI3K and phosphorylated AKT (p-AKT) both in vitro and in vivo. We found that IGF-1 induced activation of YAP/TAZ, which resulted in improved cell viability in vitro, and decreased neurological deficits, neuronal death and apoptosis, and cerebral infarct volume in vivo. Notably, the neuroprotective effects of IGF-1 were reversed by an inhibitor of the PI3K/AKT signaling pathway, LY294002, which not only reduced expressions of PI3K and p-AKT, but also down-regulated expression of YAP/TAZ, leading to aggravation of neurological dysfunction. These findings indicate that neuroprotective effect of IGF-1 is partly realized by up-regulation of YAP/TAZ, which is mediated by activation of the PI3K/AKT signaling pathway following cerebral ischemic stroke.

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Neuroprotective effects of bergenin in Alzheimer’s disease: Investigation through molecular docking, in vitro and in vivo studies

Behavioural Brain Research ◽

10.1016/j.bbr.2018.08.010 ◽

2019 ◽

Vol 356 ◽

pp. 18-40 ◽

Cited By ~ 21

Author(s):

Priyal Barai ◽

Nisith Raval ◽

Sanjeev Acharya ◽

Ankit Borisa ◽

Hardik Bhatt ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Molecular Docking ◽

In Vivo Studies ◽

Neuroprotective Effects

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Abstract WMP76: Interleukin-33 Protects Against Transient Ischemic Stroke by Enhancing Regulatory T-Cell Expansion and Accumulation

Stroke ◽

10.1161/str.51.suppl_1.wmp76 ◽

2020 ◽

Vol 51 (Suppl_1) ◽

Author(s):

Xinjing Liu ◽

Ruiyao Hu ◽

Lulu Pei ◽

Yuming Xu ◽

Bo Song

Keyword(s):

Cell Death ◽

Ischemic Stroke ◽

T Cell ◽

Regulatory T Cell ◽

Cell Expansion ◽

Neuronal Apoptosis ◽

Infarct Volume ◽

Intraperitoneal Administration

Background: The interleukin (IL)-33 could promote proliferation of regulatory T lymphocytes (Tregs) which are negatively related with brain damage after ischemic stroke. How IL-33 works on Tregs after stroke is unclear. The purpose of this study was to investigate the role of IL-33 for Tregs-mediated neuroprotection and further expounded the mechanisms of protection in mice. Methods: In vitro study, primary mice neuronal cells were subjected to 3h oxygen-glucose deprivation (OGD). The vehicle or drug conditioned Tregs were applied to neurons at the time of induction of hypoxia respectively. Neuronal apoptosis, Tregs related cytokines were measured by MTT assay, Western blotting and enzyme-linked immune-sorbent assay (ELISA). In vivo study, Tregs were depleted by intraperitoneal administration of anti-CD25Ab. Intraperitoneal injection of IL-33 immediately post 60 min transient middle cerebral artery occlusion (tMCAO) modeling. The neurological function test at days 1, 3, 5, 7 and 14 after tMCAO. Infarct volume, Brain edema, cell death, percentage of Tregs and related cytokines were respectively measured by 2,3,5-triphenyltetrazolium chloride or MAP2 staining, dry-wet method, TUNEL staining, flow cytometry and immunofluorescence, Western blotting and ELISA. Results: The supernatant of IL-33-treated Tregs reduced neuronal apoptosis in the OGD model meanwhile elevated the production of Tregs related cytokines IL-10, IL-35 and TGF- β in vitro. Intraperitoneal administration of IL-33 significantly reduced infarct volume and stroke-induced cell death and improved sensorimotor functions. Notably, the protective effect of IL-33 was abolished in mice depleted of Tregs. IL-33 increased CD4+CD25+Foxp3+ Tregs in spleens, blood, and brain in vivo. Yet, ST2 blocking muted these IL-33 activities. Mechanistically, the protection of IL-33 was associated with reduced apoptosis protein and production of Tregs related cytokine. Conclusions: This study elucidated that IL-33 afforded neuroprotection against ischemic brain injury by enhancing ST2-dependent regulatory T-cell expansion and activation, which suggested a promising immune modulatory target for the treatment of stroke.

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Design and Synthesis of New Benzo[d]oxazole-Based Derivatives and Their Neuroprotective Effects on β-Amyloid-Induced PC12 Cells

Molecules ◽

10.3390/molecules25225391 ◽

2020 ◽

Vol 25 (22) ◽

pp. 5391

Author(s):

Zheng Liu ◽

Ming Bian ◽

Qian-Qian Ma ◽

Zhuo Zhang ◽

Huan-Huan Du ◽

...

Keyword(s):

Pc12 Cells ◽

Glycogen Synthase ◽

B Cell Lymphoma ◽

Nuclear Factor Κb ◽

In Vivo Studies ◽

Neuroprotective Effects ◽

Β Amyloid ◽

Gsk 3Β

A series of novel synthetic substituted benzo[d]oxazole-based derivatives (5a–5v) exerted neuroprotective effects on β-amyloid (Aβ)-induced PC12 cells as a potential approach for the treatment of Alzheimer’s disease (AD). In vitro studies show that most of the synthesized compounds were potent in reducing the neurotoxicity of Aβ25-35-induced PC12 cells at 5 μg/mL. We found that compound 5c was non-neurotoxic at 30 μg/mL and significantly increased the viability of Aβ25-35-induced PC12 cells at 1.25, 2.5 and 5 μg/mL. Western blot analysis showed that compound 5c promoted the phosphorylation of Akt and glycogen synthase kinase (GSK-3β) and decreased the expression of nuclear factor-κB (NF-κB) in Aβ25-35-induced PC12 cells. In addition, our findings demonstrated that compound 5c protected PC12 cells from Aβ25-35-induced apoptosis and reduced the hyperphosphorylation of tau protein, and decreased the expression of receptor for AGE (RAGE), β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1), inducible nitric oxide synthase (iNOS) and Bcl-2-associated X protein/B-cell lymphoma 2 (Bax/Bcl-2) via Akt/GSK-3β/NF-κB signaling pathway. In vivo studies suggest that compound 5c shows less toxicity than donepezil in the heart and nervous system of zebrafish.

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Sirtuin 3 Mediates Neuroprotection of Ketones against Ischemic Stroke

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2015.123 ◽

2015 ◽

Vol 35 (11) ◽

pp. 1783-1789 ◽

Cited By ~ 54

Author(s):

Junxiang Yin ◽

Pengcheng Han ◽

Zhiwei Tang ◽

Qingwei Liu ◽

Jiong Shi

Keyword(s):

Ischemic Stroke ◽

Ketone Bodies ◽

Infarct Volume ◽

Field Tests ◽

Underlying Mechanism ◽

Sirtuin 3 ◽

Neuroprotective Effects ◽

Beneficial Effects ◽

Beta Hydroxybutyrate

Stroke is one of the leading causes of death. Growing evidence indicates that ketone bodies have beneficial effects in treating stroke, but their underlying mechanism remains unclear. Our previous study showed ketone bodies reduced reactive oxygen species by using NADH as an electron donor, thus increasing the NAD+/NADH ratio. In this study, we investigated whether mitochondrial NAD+-dependent Sirtuin 3 (SIRT3) could mediate the neuroprotective effects of ketone bodies after ischemic stroke. We injected mice with either normal saline or ketones (beta-hydroxybutyrate and acetoacetate) at 30 minutes after ischemia induced by transient middle cerebral artery (MCA) occlusion. We found that ketone treatment enhanced mitochondria function, reduced oxidative stress, and therefore reduced infarct volume. This led to improved neurologic function after ischemia, including the neurologic score and the performance in Rotarod and open field tests. We further showed that ketones' effects were achieved by upregulating NAD+-dependent SIRT3 and its downstream substrates forkhead box O3a (FoxO3a) and superoxide dismutase 2 (SOD2) in the penumbra region since knocking down SIRT3 in vitro diminished ketones' beneficial effects. These results provide us a foundation to develop novel therapeutics targeting this SIRT3-FoxO3a-SOD2 pathway.

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Neuroprotective and Angiogenesis Effects of Levetiracetam Following Ischemic Stroke in Rats

Frontiers in Pharmacology ◽

10.3389/fphar.2021.638209 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xiang Yao ◽

Wenping Yang ◽

Zhendong Ren ◽

Haoran Zhang ◽

Dafa Shi ◽

...

Keyword(s):

Cerebral Cortex ◽

Ischemic Stroke ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Infarct Volume ◽

Hypoxia Inducible Factor ◽

Neuronal Cell ◽

Anti Inflammatory

Objective: The present study explored whether levetiracetam (LEV) could protect against experimental brain ischemia and enhance angiogenesis in rats, and investigated the potential mechanisms in vivo and in vitro.Methods: The middle cerebral artery was occluded for 60 min to induce middle cerebral artery occlusion (MCAO). The Morris water maze was used to measure cognitive ability. The rotation test was used to assess locomotor function. T2-weighted MRI was used to assess infarct volume. The neuronal cells in the cortex area were stained with cresyl purple. The anti-inflammatory effects of LEV on microglia were observed by immunohistochemistry. Enzyme-linked immunosorbent assays (ELISA) were used to measure the production of pro-inflammatory cytokines. Western blotting was used to detect the levels of heat shock protein 70 (HSP70), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor-1α (HIF-1α) in extracts from the ischemic cortex. Flow cytometry was used to observe the effect of LEV on neuronal cell apoptosis.Results: LEV treatment significantly increased the density of the surviving neurons in the cerebral cortex and reduced the infarct size (17.8 ± 3.3% vs. 12.9 ± 1.4%, p < 0.01) after MCAO. Concurrently, the time required to reach the platform for LEV-treated rats was shorter than that in the saline group on day 11 after MCAO (p < 0.01). LEV treatment prolonged the rotarod retention time on day 14 after MCAO (84.5 ± 6.7 s vs. 59.1 ± 6.2 s on day 14 compared with the saline-treated groups, p < 0.01). It also suppressed the activation of microglia and inhibited TNF-α and Il-1β in the ischemic brain (135.6 ± 5.2 pg/ml vs. 255.3 ± 12.5 pg/ml, 18.5 ± 1.3 pg/ml vs. 38.9 ± 2.3 pg/ml on day 14 compared with the saline-treated groups, p < 0.01). LEV treatment resulted in a significant increase in HIF-1α, VEGF, and HSP70 levels in extracts from the ischemic cerebral cortex. At the same time, LEV reduced neuronal cell cytotoxicity and apoptosis induced by an ischemic stroke (p < 0.01).Conclusion: LEV treatment promoted angiogenesis and functional recovery after cerebral ischemia in rats. These effects seem to be mediated through anti-inflammatory and antiapoptotic activities, as well as inducing the expression of HSP70, VEGF, and HIF-1α.

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Neuroprotective Strategies for Neurological Disorders by Natural Products: An update

Current Neuropharmacology ◽

10.2174/1570159x16666180911124605 ◽

2019 ◽

Vol 17 (3) ◽

pp. 247-267 ◽

Cited By ~ 21

Author(s):

Muneeb U. Rehman ◽

Adil Farooq Wali ◽

Anas Ahmad ◽

Sheeba Shakeel ◽

Saiema Rasool ◽

...

Keyword(s):

Natural Products ◽

Large Scale ◽

Biological Properties ◽

In Vivo Studies ◽

Preclinical Models ◽

Neuroprotective Effects ◽

Neuroprotective Strategies ◽

Inflammatory Processes

Nature has bestowed mankind with surplus resources (natural products) on land and water. Natural products have a significant role in the prevention of disease and boosting of health in humans and animals. These natural products have been experimentally documented to possess various biological properties such as antioxidant, anti-inflammatory and anti-apoptotic activities. In vitro and in vivo studies have further established the usefulness of natural products in various preclinical models of neurodegenerative disorders. Natural products include phytoconstituents, like polyphenolic antioxidants, found in herbs, fruits, nuts, vegetables and also in marine and freshwater flora. These phytoconstituents may potentially suppress neurodegeneration and improve memory as well as cognitive functions of the brain. Also, they are known to play a pivotal role in the prevention and cure of different neurodegenerative diseases, such as Alzheimer’s disease, epilepsy, Parkinson’s disease and other neuronal disorders. The large-scale neuro-pharmacological activities of natural products have been documented due to the result of either the inhibition of inflammatory processes, or the up-regulation of various cell survival proteins or a combination of both. Due to the scarcity of human studies on neuroprotective effects of natural products, this review focuses on the various established activities of natural products in in vitro and in vivo preclinical models, and their potential neuro-therapeutic applications using the available knowledge in the literature.

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Autophagy is Involved in Neuroprotective Effect of Alpha7 Nicotinic Acetylcholine Receptor on Ischemic Stroke

Frontiers in Pharmacology ◽

10.3389/fphar.2021.676589 ◽

2021 ◽

Vol 12 ◽

Author(s):

Zhe-Qi Xu ◽

Jing-Jing Zhang ◽

Ni Kong ◽

Guang-Yu Zhang ◽

Ping Ke ◽

...

Keyword(s):

Ischemic Stroke ◽

Signaling Pathway ◽

Acetylcholine Receptor ◽

Nicotinic Acetylcholine Receptor ◽

Infarct Volume ◽

Neuroprotective Effect ◽

Autophagy Flux ◽

Nicotinic Acetylcholine

The α7 nicotinic acetylcholine receptor (α7nAChR) belongs to the superfamily of cys loop cationic ligand-gated channels, which consists of homogeneous α7 subunits. Although our lab found that activation of α7nAChR could alleviate ischemic stroke, the mechanism is still unknown. Herein, we explored whether autophagy is involved in the neuroprotective effect mediated by α7nAChR in ischemic stroke. Transient middle cerebral artery occlusion (tMCAO) and oxygen and glucose deprivation (OGD/R) exposure were applied to in vivo and in vitro models of ischemic stroke, respectively. Neurological deficit score and infarct volume were used to evaluate outcomes of tMCAO in the in vivo study. Autophagy-related proteins were detected by Western blot, and autophagy flux was detected by using tandem fluorescent mRFP-GFP-LC3 lentivirus. At 24 h after tMCAO, α7nAChR knockout mice showed worse neurological function and larger infarct volume than wild-type mice. PNU282987, an α7nAChR agonist, protected against OGD/R-induced neuronal injury, enhanced autophagy, and promoted autophagy flux. However, the beneficial effects of PNU282987 were eliminated by 3-methyladenine (3-MA), an autophagy inhibitor. Moreover, we found that PNU282987 treatment could activate the AMPK-mTOR-p70S6K signaling pathway in the in vitro study, while the effect was attenuated by compound C, an AMPK inhibitor. Our results demonstrated that the beneficial effect on neuronal survival via activation of α7nAChR was associated with enhanced autophagy, and the AMPK-mTOR-p70S6K signaling pathway was involved in α7nAChR activation–mediated neuroprotection.

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Ras-like Gem GTPase induced by Npas4 promotes activity-dependent neuronal tolerance for ischemic stroke

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2018850118 ◽

2021 ◽

Vol 118 (32) ◽

pp. e2018850118

Author(s):

Hiroo Takahashi ◽

Ryo Asahina ◽

Masayuki Fujioka ◽

Takeshi K. Matsui ◽

Shigeki Kato ◽

...

Keyword(s):

Ischemic Stroke ◽

Cortical Neurons ◽

Glucose Deprivation ◽

Artery Occlusion ◽

Small Gtpase ◽

Neuroprotective Effects ◽

Necessary And Sufficient ◽

Activity Dependent

Ischemic stroke, which results in loss of neurological function, initiates a complex cascade of pathological events in the brain, largely driven by excitotoxic Ca2+ influx in neurons. This leads to cortical spreading depolarization, which induces expression of genes involved in both neuronal death and survival; yet, the functions of these genes remain poorly understood. Here, we profiled gene expression changes that are common to ischemia (modeled by middle cerebral artery occlusion [MCAO]) and to experience-dependent activation (modeled by exposure to an enriched environment [EE]), which also induces Ca2+ transients that trigger transcriptional programs. We found that the activity-dependent transcription factor Npas4 was up-regulated under MCAO and EE conditions and that transient activation of cortical neurons in the healthy brain by the EE decreased cell death after stroke. Furthermore, both MCAO in vivo and oxygen-glucose deprivation in vitro revealed that Npas4 is necessary and sufficient for neuroprotection. We also found that this protection involves the inhibition of L-type voltage-gated Ca2+ channels (VGCCs). Next, our systematic search for Npas4-downstream genes identified Gem, which encodes a Ras-related small GTPase that mediates neuroprotective effects of Npas4. Gem suppresses the membrane localization of L-type VGCCs to inhibit excess Ca2+ influx, thereby protecting neurons from excitotoxic death after in vitro and in vivo ischemia. Collectively, our findings indicate that Gem expression via Npas4 is necessary and sufficient to promote neuroprotection in the injured brain. Importantly, Gem is also induced in human cerebral organoids cultured under an ischemic condition, revealing Gem as a new target for drug discovery.

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Vasculoprotective and Neuroprotective Effects of Various Parts of Pomegranate: In Vitro, In Vivo, and Preclinical Studies

10.5772/intechopen.96680 ◽

2021 ◽

Author(s):

Maria Trapali ◽

Vasiliki Lagouri

Keyword(s):

Ellagic Acid ◽

Therapeutic Agent ◽

Neuroprotective Effect ◽

Pomegranate Juice ◽

In Vivo Studies ◽

Neuroprotective Effects ◽

Hydrolysable Tannins ◽

Main Components

Pomegranate (Punica granatum L.) is one of the oldest edible fruits in the Mediterranean area and has been used extensively in the folk medicine. Popularity of pomegranate has increased especially in the last decade because of the health effects of the fruit. Polyphenols, represent the predominant class of phytochemicals of pomegranate, mainly consisting of hydrolysable tannins and ellagic acid. Pomegranate is a rich source of the ellagitannin punicalagin, which has aroused considerable interest in pomegranate fruit as a new therapeutic agent in recent years. Most studies on the effects of pomegranate juice have focused on its ability to cure diabetes and atherosclerosis. The present review summarizes some recent studies on the vasculoprotective and neuroprotective effect of various parts of pomegranate and its main compounds especially hydrolysable tannins ellagitannins, ellagic acid and their metabolites. The in vitro and in vivo studies, showed that the whole parts of pomegranate as well as its main components had a positive influence on blood glucose, lipid levels, oxidation stress and neuro/inflammatory biomarkers. They could be used as a future therapeutic agent towards several vascular and neurodegenerative disorders such as hypertension, coronary heart disease and Alzheimer.

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