Resveratrol protects CA1 neurons against focal cerebral ischemic reperfusion-induced damage via the ERK-CREB signaling pathway in rats

Polyphenols Targeting MAP Kinase Signaling Pathway in Neurological Diseases: Understanding Molecular Mechanisms and Therapeutic Targets

Polyphenols are a class of secondary metabolic products found in plants that have been extensively studied for how well they regulate biological processes, such as the proliferation of cells, autophagy, and apoptosis. The mitogen-activated protein kinase (MAPK)-mediated signaling cascade is currently identified as a crucial pro-inflammatory pathway that plays a significant role in the development of neuroinflammation. This process has been shown to contribute to the pathogenesis of several neurological conditions, such as Alzheimer's disease (AD), Parkinson's disease (PD), CNS damage, and cerebral ischemia. Getting enough polyphenols through eating habits has resulted in mitigating the effects of oxidative stress (OS) and lowering the susceptibility to associated neurodegenerative disorders, including but not limited to multiple sclerosis (MS), AD, stroke, and PD. Polyphenols possess significant promise in dealing with the root cause of neurological conditions by modulating multiple therapeutic targets simultaneously, thereby attenuating their complicated physiology. Several polyphenolic substances have demonstrated beneficial results in various studies and are presently undergoing clinical investigation to treat neurological diseases (NDs). The objective of this review is to provide a comprehensive summary of the different aspects of the MAPK pathway involved in neurological conditions, along with an appraisal of the progress made in using polyphenols to regulate the MAPK signaling system to facilitate the management of NDs.

Latest advances and clinical application prospects of resveratrol therapy for neurocognitive disorders

Neurocognitive disorders, such as Alzheimer's disease, vascular dementia, and postoperative cognitive dysfunction, are non-psychiatric brain syndromes in which a significant decline in cognitive function causes great trauma to the mental status of the patient. The lack of effective treatments for neurocognitive disorders imposes a considerable burden on society, including a substantial economic impact. Over the past few decades, the identification of resveratrol, a natural plant compound, has provided researchers with an opportunity to formulate novel strategies for the treatment of neurocognitive disorders. This is because resveratrol effectively protects the brain of those with neurocognitive disorders by targeting some mechanisms such as inflammation and oxidative stress. This article reviews the status of recent research investigating the use of resveratrol for the treatment of different neurocognitive disorders. By examining the possible mechanisms of action of resveratrol and the shared mechanisms of different neurocognitive disorders, treatments for neurocognitive disorders may be further clarified.

Effect and mechanisms of resveratrol in animal models of ischemic stroke: A systematic review and Bayesian meta-analysis

Resveratrol (RSV) holds promise as cerebroprotective treatment in cerebral ischemia. This systematic review aims to assess the effects and mechanisms of RSV in animal models of ischemic stroke. We searched Medline, Embase and Web of Science to identify 75 and 57 eligible rodent studies for qualitative and quantitative syntheses, respectively. Range of evidence met 10 of 13 STAIR criteria. Median (Q1, Q3) quality score was 7 (5, 8) on the CAMARADES 15-item checklist. Bayesian meta-analysis showed SMD estimates (95% CI) favoring RSV: infarct size (-1.72 [-2.03; -1.41]), edema size (-1.61 [-2.24; -0.98]), BBB impairment (-1.85 [-2.54; -1.19]), neurofunctional impairment (-1.60 [-1.92; -1.29]), and motor performance (1.39 [0.64; 2.08]); and less probably neuronal survival (0.63 [-1.40; 2.48]) and apoptosis (-0.96 [-2.87; 1.02]). Species (rat vs mouse) was associated to a larger benefit. Sensitivity analyses confirmed robustness of the estimates. Reduction of oxidative stress, inflammation, and apoptosis underlie these effects. Our results quantitatively state the beneficial effects of RSV on structural and functional outcomes in rodent stroke models, update the evidence on the mechanisms of action, and provide an exhaustive list of targeted signaling pathways. Current evidence highlights the need for conducting further high-quality preclinical research to better inform clinical research.

Mechanism of Resveratrol Improving Ischemia-Reperfusion Injury by Regulating Microglial Function Through microRNA-450b-5p/KEAP1/Nrf2 Pathway

Alterations in the M1/M2 polarization phenotype significantly affect disease progression. Antioxidant and anti-inflammatory protective effects of resveratrol (Res) have been demonstrated. This paper tested the hypothesis that Res could protect against cerebral ischemia-reperfusion injury (CI/RI) by modulating microglial polarization via the miR-450b-5p/KEAP1/Nrf2 pathway. Rats were first treated with Res and adenovirus that interfered with miR-450b-5p or KEAP1, and then established a middle cerebral artery occlusion-reperfusion model using modified nylon sutures. Rats were then evaluated for neurological and behavioral functions, and markers of M2 microglia were detected by immunofluorescence staining. Additionally, the signature patterns of miR-450b-5p, KEAP1, and Nrf2 were determined. The collected data demonstrated that Res exerted neuroprotective effects in CI/RI by promoting microglial M2 polarization. Additionally, Res could regulate the Nrf2 pathway by targeting KEAP1 by up-regulating miR-450b-5p. Up-regulating miR-450b-5p or down-regulating KEAP1 could further promote the protective effect of Res, while down-regulating miR-450b-5p or up-regulating KEAP1 worked oppositely. Our study demonstrates that Res exerts neuroprotective effects on microglial M2 polarization through the miR-450b-5p/KEAP1/Nrf2 pathway during CI/RI.

Icaritin alleviates cerebral ischemia‒reperfusion injury by regulating NMDA receptors through ERK signaling

N-methyl-D-aspartate (NMDA) receptors are key signaling molecules that mediate excitotoxicity during cerebral ischemia. GluN2A-containing NMDA receptors, which are mostly located in the intrasynaptic region, mediate normal physiological processes and promote neuronal survival. GluN2B-containing NMDA receptors, which are mostly located in the extrasynaptic region, mediate excitotoxicity injury and promote neuronal death during ischemia. This study investigated the ability of icaritin (ICT) to protect against cerebral ischemia‒reperfusion injury (CI/RI) by regulating GluN2B-containing NMDA receptors through extracellular signaling regulatory kinases/death associated protein kinase 1 (ERK/DAPK1) signaling. A rat CI/RI model was established by transient middle cerebral artery occlusion (tMCAO). Following treatment with ICT and the ERK-specific inhibitor U0126, cerebral infarction, neurological function, and excitotoxicity-related molecule expression were assessed 24 h after reperfusion. ICT treatment significantly decreased cerebral infarct volume, improved neurological function, and regulated NMDA receptor subtype expression and ERK/DAPK1 signaling activation. The ability of ICT to increase GluN2A and postsynaptic density protein 95 (PSD95) mRNA and protein expression, inhibit GluN2B expression, and regulate DAPK1 activation was reversed after administration of the ERK-specific inhibitor U0126. These data indicated that ICT inhibited excitotoxicity injury and exerted a protective effect against CI/RI that was likely mediated by increased ERK signaling pathway activation and regulation of extrasynaptic and intrasynaptic NMDA receptor function, providing a new therapeutic target for ischemic encephalopathy.

Study on Neuroprotective Mechanism of Houshiheisan in Ischemic Stroke Based on Transcriptomics and Experimental Verification

Houshiheisan (HSHS), a classic prescription in traditional Chinese medicine (TCM), has shown outstanding efficacy in treating stroke. This study investigated various therapeutic targets of HSHS for ischemic stroke using mRNA transcriptomics. Herein, rats were randomly separated into the sham, model, HSHS 5.25 g/kg (HSHS5.25), and HSHS 10.5 g/kg (HSHS10.5) groups. Rats suffering from stroke were induced by permanent middle cerebral artery occlusion (pMCAO). After seven days of HSHS treatment, behavioral tests were conducted, and histological damage was examined with hematoxylin-eosin (HE). The mRNA expression profiles were identified using microarray analysis and quantitative real-time PCR (qRT-PCR) validated gene expression changes. An analysis of gene ontology and pathway enrichment was conducted to analyze potential mechanisms confirmed using immunofluorescence and western blotting. HSHS5.25 and HSHS10.5 improved neurological deficits and pathological injury in pMCAO rats. The intersections of 666 differentially expressed genes (DEGs) were chosen using transcriptomics analysis in the sham, model, and HSHS10.5 groups. The enrichment analysis suggested that the therapeutic targets of HSHS might regulate the apoptotic process and ERK1/2 signaling pathway, which was related to neuronal survival. Moreover, TUNEL and immunofluorescence analysis indicated that HSHS inhibited apoptosis and enhanced neuronal survival in the ischemic lesion. Western blot and immunofluorescence assay indicated that HSHS10.5 decreased Bax/Bcl-2 ratio and suppressed caspase-3 activation, while the phosphorylation of ERK1/2 and CREB was upregulated in a stroke rat model after HSHS treatment. Effective inhibition of neuronal apoptosis by activating the ERK1/2-CREB signaling pathway may be a potential mechanism for HSHS in the treatment of ischemic stroke.

The combination of Astragalus membranaceus and ligustrazine mitigates cerebral ischemia-reperfusion injury via regulating NR2B-ERK/CREB signaling

BACKGROUND AND PURPOSE

Cerebral ischemia-reperfusion (I/R) injury is a major factor underlying the high mortality and morbidity rates in stroke patients. Our previous study found that the combination of Astragalus membranaceus extract and ligustrazine (Ast+Lig) treatment could protect brain tissues against inflammation in rats with thrombolytic cerebral ischemia. Activation of N-methyl-D-aspartate receptors (NMDAR) is implicated in brain damage induced by cerebral I/R injury.

METHODS

We used in vivo and in vitro models of cerebral I/R injury for middle cerebral artery occlusion/reperfusion in mice and oxygen-glucose deprivation/reoxygenation in primary rat cerebral cortical neurons to evaluate the protective effects of Ast+Lig on cerebral I/R injury, and whether the protective mechanism was related to the regulation of NMDAR-ERK/CREB signaling.

RESULTS

Treatment with Ast+Lig, or MK-801 (an inhibitor of NMDAR) significantly ameliorated neurological deficits, decreased infarct volumes, suppressed neuronal damage and Ca²⁺ influx, and maintained the mitochondrial membrane potential in vivo and in vitro following cerebral I/R injury based on 2,3,5-triphenyl tetrazolium chloride staining, immunohistochemistry, and immunofluorescent staining. Furthermore, treatment with Ast+Lig evidently prevented the upregulation of NR2B, but not NR2A, in vivo and in vitro following cerebral I/R injury based on western blotting and reverse transcription-quantitative PCR analyses. Moreover, treatment with Ast+Lig significantly increased the phosphorylation of ERK and CREB, as well as increasing their mRNA expression levels in vivo and in vitro following cerebral I/R injury.

CONCLUSIONS

The overall results thus suggest that the Ast+Lig combination conferred neuroprotective properties against cerebral I/R injury via regulation of the NR2B-ERK/CREB signaling pathway.

Exosomes-based therapy of stroke, an emerging approach toward recovery

Based on clinical observations, stroke is touted as one of the specific pathological conditions, affecting an individual’s life worldwide. So far, no effective treatment has been introduced to deal with stroke post-complications. Production and release of several neurotrophic factors by different cells exert positive effects on ischemic areas following stroke. As a correlate, basic and clinical studies have focused on the development and discovery of de novo modalities to introduce these factors timely and in appropriate doses into the affected areas. Exosomes (Exo) are non-sized vesicles released from many cells during pathological and physiological conditions and participate in intercellular communication. These particles transfer several arrays of signaling molecules, like several neurotrophic factors into the acceptor cells and induce specific signaling cascades in the favor of cell bioactivity. This review aimed to highlight the emerging role of exosomes as a therapeutic approach in the regeneration of ischemic areas.

Yuk-Gunja-Tang attenuates neuronal death and memory impairment via ERK/CREB/BDNF signaling in the hippocampi of experimental Alzheimer’s disease model

Yuk-Gunja-Tang (YG) is the Korean traditional medicine in East Asia for gastrointestinal disorders. In the present study, we determined the protective effects of YG on glutamate-induced cytotoxicity in HT22 hippocampal neuronal cells and mice with scopolamine-induced memory impairment. In vitro assessments were performed using a cell viability assay, flow cytometry, and Western blotting, while in vivo assessments were performed in C57BL/6 mice administered with YG for 7 days and injected with scopolamine (1 mg/kg) for 7 days. We assessed the memory function using the Y-maze, novel object recognition, and passive avoidance tests. Protein expression analyses and histological analyses were performed using hippocampal tissues. YG treatment significantly restored cell viability against glutamate-induced apoptosis. It significantly suppressed glutamate-induced reactive oxygen species accumulation and mitochondrial dysfunction. It also increased Bcl-2 protein expression and decreased HO-1 protein expression. It activated the extracellular signal-regulated kinase/cAMP response element binding protein (ERK/CREB) signaling pathway and increased the expression of brain-derived neurotrophic factor (BDNF) under excitotoxic conditions. In the scopolamine-injected mice, YG ameliorated memory impairment in the Y-maze, novel object recognition, and passive avoidance tests; restored dysfunction in the acetylcholine, acetylcholinesterase expression levels; reduced neuronal damage in Nissl staining; and increased BDNF and phosphorylated ERK and CREB levels in Western blotting and immunofluorescence staining. Thus, YG exerted neuroprotective effects by activating ERK/CREB/BDNF signaling in the hippocampus, indicating its potential cognition-enhancing effects, especially in Alzheimer’s disease.

A meta-analysis of resveratrol protects against cerebral ischemia/reperfusion injury: Evidence from rats studies and insight into molecular mechanisms

Objective: To evaluate the neuroprotective effect of resveratrol (RES) in rat models of cerebral ischemia/reperfusion (I/R) injury.

Data sources: PubMed, Embase, MEDLINE, Cochrane Library, and Chinese databases were searched from their inception dates to July 2022. No language restriction was used in the literature search.

Date Selection: Studies were selected that RES were used to treat cerebral I/R injury in vivo. Two reviewers conducted literature screening, data extraction and methodological quality assessment independently.

Outcome measures: Cerebral infarct volume was included as primary outcome. The secondary outcomes included cerebral water content and neurological deficit scores. Malondialdehyde (MDA) and superoxide dismutase (SOD) were used to evaluate oxidative stress during medication.

Results: A total of 41 studies were included, and only a few of them the methodological quality was relatively low. Compared with the control group, RES significantly reduced the cerebral infarct volume (29 studies, standard mean difference (SMD) = −2.88 [−3.23 to −2.53], p < 0.00001) and brain water content (nine studies, MD = −9.49 [−13.58 to −5.40], p < 0.00001) after cerebral I/R injury, then neurological function was improved (15 studies, SMD = −1.96 [−2.26 to −1.65], p < 0.00001). The MDA level (six studies, SMD = −8.97 [−13.60 to −4.34], p = 0.0001) was decreased notably after treatment of RES, while the SOD level (five studies, SMD = 3.13 [−0.16 to 6.43], p = 0.06) was increased unsatisfactory. Consistently, subgroup analysis of cerebral infarct volume suggested that the optimal therapeutic dose is 30 mg/kg (eight studies, SMD = −5.83 [−7.63 to −4.04], p < 0.00001). Meanwhile, 60 min of occlusion (three studies, SMD = −10.89 [−16.35 to −5.42], p < 0.0001) could get maximum benefit from compared with 90 min and 120 min of occlusion. On the other hand, the publication bias cannot be ignored. The pharmacological mechanisms of RES on cerebral I/R injury models as reported have be summarized, which can be used for reference by researchers to further plan their future experiments.

Conclusion: RES might have a good neuroprotective effect on cerebral I/R injury in rats, then 30 mg/kg RES may be the optimal dose for treatment, and early administration of RES should be more neuroprotective. Also it need to be further verified through exploration of dose effect relationship, or delay administration or not.

Antioxidant and neuroprotective actions of resveratrol in cerebrovascular diseases

Cerebralvascular diseases are the most common high-mortality diseases worldwide. Despite its global prevalence, effective treatments and therapies need to be explored. Given that oxidative stress is an important risk factor involved with cerebral vascular diseases, natural antioxidants and its derivatives can be served as a promising therapeutic strategy. Resveratrol (3, 5, 4′-trihydroxystilbene) is a natural polyphenolic antioxidant found in grape skins, red wine, and berries. As a phytoalexin to protect against oxidative stress, resveratrol has therapeutic value in cerebrovascular diseases mainly by inhibiting excessive reactive oxygen species production, elevating antioxidant enzyme activity, and other antioxidant molecular mechanisms. This review aims to collect novel kinds of literature regarding the protective activities of resveratrol on cerebrovascular diseases, addressing the potential mechanisms underlying the antioxidative activities and mitochondrial protection of resveratrol. We also provide new insights into the chemistry, sources, and bioavailability of resveratrol.

Resveratrol has an Overall Neuroprotective Role in Ischemic Stroke: A Meta-Analysis in Rodents

Background: Resveratrol, a natural polyphenolic phytoalexin, is broadly presented in dietary sources. Previous research has suggested its potential neuroprotective effects on ischemic stroke animal models. However, these results have been disputable. Here, we conducted a meta-analysis to comprehensively evaluate the effect of resveratrol treatment in ischemic stroke rodent models.

Objective: To comprehensively evaluate the effect of resveratrol treatment in ischemic stroke rodent models.

Methods: A literature search of the databases Pubmed, Embase, and Web of science identified 564 studies that were subjected to pre-defined inclusion criteria. 54 studies were included and analyzed using a random-effects model to calculate the standardized mean difference (SMD) with corresponding confidence interval (CI).

Results: As compared with controls, resveratrol significantly decreased infarct volume (SMD −4.34; 95% CI −4.98 to −3.69; p < 0.001) and the neurobehavioral score (SMD −2.26; 95% CI −2.86 to −1.67; p < 0.001) in rodents with ischemic stroke. Quality assessment was performed using a 10-item checklist. Studies quality scores ranged from 3 to 8, with a mean value of 5.94. In the stratified analysis, a significant decrease of infarct volume and the neurobehavioral score was achieved in resveratrol sub-groups with a dosage of 20–50 mg/kg. In the meta-regression analysis, the impact of the delivery route on an outcome is the possible source of high heterogeneity.

Conclusion: Generally, resveratrol treatment presented neuroprotective effects in ischemic stroke models. Furthermore, this study can direct future preclinical and clinical trials, with important implications for human health.

The protective effect of cannabinoid type II receptor agonist AM1241 on ConA-induced liver injury in mice via mitogen-activated protein kinase signalling pathway

Introduction

The endocannabinoid system plays an important role in regulating the immune responses in inflammation. At present, there are no good clinical drugs for many immune liver diseases.

Methods

We explored the protective effect of the cannabinoid type II (CB2) receptor agonist AM1241 on the liver of mice with acute liver injury caused by concanavalin from the perspective of inflammation and immunity. Pathological evaluation in hepatic tissue was examined by haematoxylin and eosin (HE) staining and the levels of biochemical parameters in the serum were measured by automatic biochemical analysis. The content of inflammatory factors was measured by enzyme-linked immunosorbent assay and real-time quantitative reverse transcription polymerase chain reaction (real-time PCR). The liver apoptosis-related proteins were observed by immunohistochemistry. The expression of liver injury-related proteins was analysed by Western blot. Immune cells were isolated from the liver of mice and studied in vitro.

Results

Reduced levels of alanine transaminase and aspartate transaminase were observed in ConA-induced liver injury mice treated with AM1241, together with attenuated liver damage evidenced by H&E staining. Moreover, AM1241 inhibited the protein and gene expression levels of TNF-α, IL-6 and IFN-γ in the livers of mice. The phosphorylation levels of p38, JNK, ERK1/2, P65 and cAMP response element-binding protein (CREB) in the mouse were significantly reduced in AM1241 pretreatment, while the level of p-JNK increased. In addition, the P/T-P65 and P/T-CREB of the AM1241 pretreatment group were significantly reduced. The results of immunohistochemistry measurement are consistent with those of Western blotting. The CB2-mediated effect is through macrophage-like Kupffer cells.

Conclusion

Our study suggests that the ConA-induced liver injury model in mice is protected by CB2 agonist AM1241 by modulation of CB2 receptor-rich immune cells, for example, Kupffer cells. Reduced inflammatory responses regulate apoptosis/cell death in the liver particularly hepatocytes and other parenchymal cells.

Therapeutic Effects of Resveratrol on Ischemia-Reperfusion Injury in the Nervous System

Resveratrol is a phenol compound produced by some plants in response to pathogens, infection, or physical injury. It is well-known that resveratrol has antioxidant and protective roles in damages potentially caused by cancer or other serious disorders. Thus, it is considered as a candidate agent for the prevention and treatment of human diseases. Evidence has confirmed other bioactive impacts of resveratrol, including cardioprotective, anti-tumorigenic, anti-inflammatory, phytoestrogenic, and neuroprotective effects. Ischemia-reperfusion (IR) can result in various disorders, comprising myocardial infarction, stroke, and peripheral vascular disease, which may continue to induce debilitating conditions and even mortality. In virtue of chronic ischemia or hypoxia, cells switch to anaerobic metabolism, giving rise to some dysfunctions in mitochondria. As the result of lactate accumulation, adenosine triphosphate levels and pH decline in cells. This condition leads cells to apoptosis, necrosis, and autophagy. However, restoring oxygen level upon reperfusion after ischemia by producing reactive oxygen species is an outcome of mitochondrial dysfunction. Considering the neuroprotective effect of resveratrol and neuronal injury that comes from IR, we focused on the mechanism(s) involved in IR injury in the nervous system and also on the functions of resveratrol in the protection, inhibition, and treatment of this injury.

Icaritin Alleviates Glutamate-Induced Neuronal Damage by Inactivating GluN2B-Containing NMDARs Through the ERK/DAPK1 Pathway

Excitatory toxicity due to excessive glutamate release is considered the core pathophysiological mechanism of cerebral ischemia. It is primarily mediated by N-methyl-D-aspartate receptors (NMDARs) on neuronal membranes. Our previous studies have found that icaritin (ICT) exhibits neuroprotective effects against cerebral ischemia in rats, but the underlying mechanism is unclear. This study aims to investigate the protective effect of ICT on glutamate-induced neuronal injury and uncover its possible molecular mechanism. An excitatory toxicity injury model was created using rat primary cortical neurons treated with glutamate and glycine. The results showed that ICT has neuroprotective effects on glutamate-treated primary cortical neurons by increasing cell viability while reducing the rate of lactate dehydrogenase (LDH) release and reducing apoptosis. Remarkably, ICT rescued the changes in the ERK/DAPK1 signaling pathway after glutamate treatment by increasing the expression levels of p-ERK, p-DAPK1 and t-DAPK1. In addition, ICT also regulates NMDAR function during glutamate-induced injury by decreasing the expression level of the GluN2B subunit and enhancing the expression level of the GluN2A subunit. As cotreatment with the ERK-specific inhibitor U0126 and ICT abolishes the beneficial effects of ITC on the ERK/DAPK1 pathway, NMDAR subtypes and neuronal cell survival, ERK is recognized as a crucial mediator in the protective mechanism of ICT. In conclusion, our findings demonstrate that ICT has a neuroprotective effect on neuronal damage induced by glutamate, and its mechanism may be related to inactivating GluN2B-containing NMDAR through the ERK/DAPK1 pathway. This study provides a new clue for the prevention and treatment of clinical ischemic cerebrovascular diseases.

Resveratrol noncompetitively inhibits glycine receptor-mediated currents in neurons of rat central auditory neurons

Resveratrol, a naturally occurring stilbene found in red wine, is known to modulate the activity of several types of ion channels and membrane receptors, including Ca²⁺, K⁺, and Na⁺ ion channels. However, little is known about the effects of resveratrol on some important receptors, such as glycine receptors and GABA_A receptors, in the central nervous system (CNS). In the present study, the effects of resveratrol on glycine receptor or GABA_A receptor-mediated currents in cultured rat inferior colliculus (IC) and auditory cortex (AC) neurons were studied using whole-cell voltage-clamp recordings. Resveratrol itself did not evoke any currents in IC neurons but it reversibly decreased the amplitude of glycine-induced current (I_Gly) in a concentration-dependent manner. Resveratrol did not change the reversal potential of I_Gly but it shifted the concentration-response relationship to the right without changing the Hill coefficient and with decreasing the maximum response of I_Gly. Interestingly, resveratrol inhibited the amplitude of I_Gly but not that of GABA-induced current (I_GABA) in AC neurons. More importantly, resveratrol inhibited GlyR-mediated but not GABA_AR-mediated inhibitory postsynaptic currents in IC neurons using brain slice recordings. Together, these results demonstrate that resveratrol noncompetitively inhibits I_Gly in auditory neurons by decreasing the affinity of glycine to its receptor. These findings suggest that the native glycine receptors but not GABA_A receptors in central neurons are targets of resveratrol during clinical administrations.

Implications of the Human Gut-Brain and Gut-Cancer Axes for Future Nanomedicine

Recent clinical and pathological evidence have implicated the gut microbiota as a nexus for modulating the homeostasis of the human body, impacting conditions from cancer and dementia to obesity and social behavior. The connections between microbiota and human diseases offer numerous opportunities in medicine, most of which have limited or no therapeutic solutions available. In light of this paradigm-setting trend in science, this review aims to provide a comprehensive and timely summary of the mechanistic pathways governing the gut microbiota and their implications for nanomedicines targeting cancer and neurodegenerative diseases. Specifically, we discuss in parallel the beneficial and pathogenic relationship of the gut microbiota along the gut-brain and gut-cancer axes, elaborate on the impact of dysbiosis and the gastrointestinal corona on the efficacy of nanomedicines, and highlight a molecular mimicry that manipulates the universal cross-β backbone of bacterial amyloid to accelerate neurological disorders. This review further offers a forward-looking section on the rational design of cancer and dementia nanomedicines exploiting the gut-brain and gut-cancer axes.

Review Cerebral Ischemic Tolerance and Preconditioning: Methods, Mechanisms, Clinical Applications, and Challenges

Stroke is one of the leading causes of morbidity and mortality worldwide, and it is increasing in prevalence. The limited therapeutic window and potential severe side effects prevent the widespread clinical application of the venous injection of thrombolytic tissue plasminogen activator and thrombectomy, which are regarded as the only approved treatments for acute ischemic stroke. Triggered by various types of mild stressors or stimuli, ischemic preconditioning (IPreC) induces adaptive endogenous tolerance to ischemia/reperfusion (I/R) injury by activating a multitude cascade of biomolecules, for example, proteins, enzymes, receptors, transcription factors, and others, which eventually lead to transcriptional regulation and epigenetic and genomic reprogramming. During the past 30 years, IPreC has been widely studied to confirm its neuroprotection against subsequent I/R injury, mainly including local ischemic preconditioning (LIPreC), remote ischemic preconditioning (RIPreC), and cross preconditioning. Although LIPreC has a strong neuroprotective effect, the clinical application of IPreC for subsequent cerebral ischemia is difficult. There are two main reasons for the above result: Cerebral ischemia is unpredictable, and LIPreC is also capable of inducing unexpected injury with only minor differences to durations or intensity. RIPreC and pharmacological preconditioning, an easy-to-use and non-invasive therapy, can be performed in a variety of clinical settings and appear to be more suitable for the clinical management of ischemic stroke. Hoping to advance our understanding of IPreC, this review mainly focuses on recent advances in IPreC in stroke management, its challenges, and the potential study directions.

Hypertension and changes in cognitive function in a Mediterranean population

Background: Severe cognitive decline is one of the major public health problems in developed countries. Finding modifiable risk factors could become essential to develop strategies to prevent or delay dementia progression and stop its rising incidence.Objective: Our aim was to investigate the association between hypertension and cognitive function and to assess whether better adherence to the Mediterranean diet may modify this association.Methods: A subsample of 764 participants from the 'Seguimiento Universidad de Navarra' (SUN) cohort older than 55 years was evaluated with the Spanish Telephone Interview for Cognitive Status (TICS-m) at two-time points, separated by 6 years. Multivariable-adjusted linear regression models were used to prospectively assess the association between hypertension -also according to adherence to the Mediterranean diet- and 6-y changes in cognitive function.Results: The adjusted between-group difference in the 6-year change of the TICS-m score between hypertensive participants and their non-hypertensive counterparts was -0.36 (95% CI -0.70, -0.02). This association was stronger among participants with a lower adherence to the Mediterranean diet [-0.62 (95% CI: -1.09, -0.15)] but the differences between hypertensive and non-hypertensive participants were no longer significant among participants with a higher baseline adherence to the Mediterranean diet.Conclusion: In this Mediterranean cohort, hypertension was inversely associated with cognitive function, but an attenuation of this detrimental association by a moderate/high adherence to the Mediterranean diet was suggested.

Targeting Myeloperoxidase (MPO) Mediated Oxidative Stress and Inflammation for Reducing Brain Ischemia Injury: Potential Application of Natural Compounds

Oxidative stress and inflammation are two critical pathological processes of cerebral ischemia-reperfusion injury. Myeloperoxidase (MPO) is a critical inflammatory enzyme and therapeutic target triggering both oxidative stress and neuroinflammation in the pathological process of cerebral ischemia-reperfusion injury. MPO is presented in infiltrated neutrophils, activated microglial cells, neurons, and astrocytes in the ischemic brain. Activation of MPO can catalyze the reaction of chloride and H2O2 to produce HOCl. MPO also mediates oxidative stress by promoting the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS), modulating the polarization and inflammation-related signaling pathways in microglia and neutrophils. MPO can be a therapeutic target for attenuating oxidative damage and neuroinflammation in ischemic stroke. Targeting MPO with inhibitors or gene deficiency significantly reduced brain infarction and improved neurological outcomes. This article discusses the important roles of MPO in mediating oxidative stress and neuroinflammation during cerebral ischemia-reperfusion injury and reviews the current understanding of the underlying mechanisms. Furthermore, we summarize the active compounds from medicinal herbs with potential as MPO inhibitors for anti-oxidative stress and anti-inflammation to attenuate cerebral ischemia-reperfusion injury, and as adjunct therapeutic agents for extending the window of thrombolytic treatment. We highlight that targeting MPO could be a promising strategy for alleviating ischemic brain injury, which merits further translational study.

Polyphenols in Alzheimer's Disease and in the Gut-Brain Axis

Polyphenolic antioxidants, including dietary plant lignans, modulate the gut-brain axis, which involves transformation of these polyphenolic compounds into physiologically active and neuroprotector compounds (called human lignans) through gut bacterial metabolism. These gut bacterial metabolites exert their neuroprotective effects in various neurodegenerative diseases, such as Alzheimer's disease (AD) and Parkinson's disease (PD), and also have protective effects against other diseases, such as cardiovascular diseases, cancer, and diabetes. For example, enterolactone and enterodiol, the therapeutically relevant polyphenols, are formed as the secondary gut bacterial metabolites of lignans, the non-flavonoid polyphenolic compounds found in plant-based foods. These compounds are also acetylcholinesterase inhibitors, and thereby have potential applications as therapeutics in AD and other neurological diseases. Polyphenols are also advanced glycation end product (AGE) inhibitors (antiglycating agents), and thereby exert neuroprotective effects in cases of AD. Thus, gut bacterial metabolism of lignans and other dietary polyphenolic compounds results in the formation of neuroprotective polyphenols-some of which have enhanced blood-brain barrier permeability. It is hypothesized that gut bacterial metabolism-derived polyphenols, when combined with the nanoparticle-based blood-brain barrier (BBB)-targeted drug delivery, may prove to be effective therapeutics for various neurological disorders, including traumatic brain injury (TBI), AD, and PD. This mini-review addresses the role of polyphenolic compounds in the gut-brain axis, focusing on AD.

Rapid antidepressant actions of imipramine potentiated by zinc through PKA-dependented regulation of mTOR and CREB signaling

The slow onset of traditional antidepressants has become an urgent clinical issue, researchers are constantly exploring new antidepressants with prompt action. Previous studies have found that zinc levels were decreased in serum and brain of depressed patients or animal models. Zinc treatment can improve depressive symptoms and enhance the antidepressant effects of monoamine antidepressants. However, its mechanism of action is still unclear. This present study aims to investigate whether the zinc can enhance the rapid action of traditional antidepressant imipramine and to explore the potential mechanisms of action through the rapid antidepressant targets CREB (cAMP-response element binding protein) and mTOR (mammalian target of the rapamycin). Drug treatment included intraperitoneal injection of imipramine or zinc alone and imipramine plus zinc. Zinc had a rapid enhanced antidepressive effect on the imipramine and achieved a rapid antidepressant effect similar to ketamine. Combination of zinc with imipramine rapidly enhanced the phosphorylation of mTOR Ser2448 and CREB Ser133, and increased the expression of mTOR and CREB, which were dependent on the activation of PKA. In conclusion, combination therapy with zinc and monoamine antidepressants may overcome the problem of slow-onset action of traditional antidepressants in clinical uses.

Resveratrol modulates the Akt/GSK-3β signaling pathway in a middle cerebral artery occlusion animal model

Cerebral ischemia is a major cause of neurodegenerative disease. It induces neuronal vulnerability and susceptibility, and leads to neuronal cell death. Resveratrol is a polyphenolic compound that acts as an anti-oxidant. It exerts a neuroprotective effect against focal cerebral ischemic injury. Akt signaling pathway is accepted as a representative cell survival pathway, including proliferation, growth, and glycogen synthesis. This study investigated whether resveratrol regulates Akt/glycogen synthase kinase-3β (GSK-3β) pathway in a middle cerebral artery occlusion (MCAO)-induced ischemic brain injury. Adult male rats were intraperitoneally injected with vehicle or resveratrol (30 mg/kg) and cerebral cortices were isolated 24 h after MCAO. Neurological behavior test, corner test, brain edema measurment, and 2,3,5-triphenyltetrazolium chloride staining were performed to elucidate the neuroprotective effects of resveratrol. Phospho-Akt and phospho-GSK-3β expression levels were measured using Western blot analysis. MCAO injury led to severe neurobehavioral deficit, infraction, and histopathological changes in cerebral cortex. However, resveratrol treatment alleviated these changes caused by MCAO injury. Moreover, MCAO injury induced decreases in phospho-Akt and phospho-GSK-3β protein levels, whereas resveratrol attenuated these decreases. Phosphorylations of Akt and GSK-3β act as a critical role for the suppression of apoptotic cell death. Thus, our finding suggests that resveratrol attenuates neuronal cell death in MCAO-induced cerebral ischemia and Akt/GSK-3β signaling pathway contributes to the neuroprotective effect of resveratrol.

Potential for diet to prevent and remediate cognitive deficits in neurological disorders

The pathophysiology of many neurological disorders involves oxidative stress, neuroinflammation, and mitochondrial dysfunction. There is now substantial evidence that diet can decrease these forms of pathophysiology, and an emerging body of literature relatedly suggests that diet can also prevent or even remediate the cognitive deficits observed in neurological disorders that exhibit such pathology (eg, Alzheimer's disease, multiple sclerosis, age-related cognitive decline, epilepsy). The current review summarizes the emerging evidence in relation to whole diets prominent in the scientific literature-ketogenic, caloric restriction, high polyphenol, and Mediterranean diets-and provides a discussion of the possible underlying neurophysiological mechanisms.

Phosphatidylethanolamine-binding protein 1 protects CA1 neurons against ischemic damage via ERK-CREB signaling in Mongolian gerbils

In the present study, we made a PEP-1-phosphatidylethanolamine-binding protein 1 (PEP-1-PEBP1) fusion protein to facilitate the transduction of PEBP1 into cells and observed significant ameliorative effects of PEP-1-PEBP1 against H₂O₂-induced neuronal damage and the formation of reactive oxygen species in the HT22 hippocampal cells. In addition, administration of PEP-1-PEBP1 fusion protein ameliorated H₂O₂-induced phosphorylation of extracellular signal-regulated kinases (ERK1/2) and facilitated the phosphorylation of cyclic-AMP response element binding protein (CREB) in HT22 cells after exposure to H₂O₂. We also investigated the temporal and spatial changes of phosphorylated phosphatidylethanolamine-binding protein 1 (pPEBP1) in the hippocampus, after 5 min of transient forebrain ischemia in gerbils. In the sham-operated animals, pPEBP1 immunoreactivity was not detectable in the hippocampal CA1 region. pPEBP1 immunoreactivity was significantly increased in the hippocampal CA1 region, 1-2 days after ischemia, compared to that in the sham-operated group and pPEBP1 immunoreactivity was returned to levels in sham-operated group at 3-4 days after ischemia. pPEBP1 immunoreactivity significantly increased at day 7 after ischemia and decreased to sham-operated group levels by day 10 after ischemia/reperfusion. In addition, administration of PEP-1-PEBP1 fusion protein significantly reduced the ischemia-induced hyperactivity of locomotion, 1 day after ischemia and PEP-1-PEBP1 reduced neuronal damage and reactive gliosis (astrocytosis and microgliosis) in the gerbil hippocampal CA1 region, 4 days after ischemia. Administration of PEP-1-PEBP1 fusion protein ameliorated the ischemia-induced phosphorylation of ERK at 3 h and 6 h after ischemia/reperfusion and accelerated the phosphorylation of CREB in ischemic hippocampus at 6 h after ischemia. These results suggest that the increase in PEBP1 phosphorylation causes neuronal damage in the hippocampus and treatment with PEP-1-PEBP1 fusion protein provides neuroprotection from increasing phosphorylation of ERK-CREB pathways in the hippocampal CA1 region, during ischemic damage.

Role of the Extracellular Signal-Regulated Kinase 1/2 Signaling Pathway in Ischemia-Reperfusion Injury

Extracellular signal-regulated kinase 1/2 (ERK_1/2), an important member of the mitogen-activated protein kinase family, is found in many organisms, and it participates in intracellular signal transduction. Various stimuli induce phosphorylation of ERK_1/2 in vivo and in vitro. Phosphorylated ERK_1/2 moves to the nucleus, activates many transcription factors, regulates gene expression, and controls various physiological processes, finally inducing repair processes or cell death. With the aging of the population around the world, the occurrence of ischemia-reperfusion injury (IRI), especially in the brain, heart, kidney, and other important organs, is becoming increasingly serious. Abnormal activation of the ERK_1/2 signaling pathway is closely related to the development and the metabolic mechanisms of IRI. However, the effects of this signaling pathway and the underlying mechanism differ between various models of IRI. This review summarizes the ERK_1/2 signaling pathway and the molecular mechanism underlying its role in models of IRI in the brain, heart, liver, kidneys, and other organs. This information will help to deepen the understanding of ERK_1/2 signals and deepen the exploration of IRI treatment based on the ERK_1/2 study.

Behavioral and molecular effects of intrahippocampal infusion of auraptene, resveratrol, and curcumin on H-89-induced deficits on spatial memory acquisition and retention in Morris water maze

Our aim was to investigate the effects of resveratrol, auraptene, and curcumin on the spatial learning and spatial memory retention in the Morris water maze (MWM). The effects of 4-day bilateral intrahippocampal (i.h.) infusions of dimethyl sulfoxide (DMSO), H-89 as a protein kinase AII inhibitor, auraptene/H-89, resveratrol/H-89, and curcumin/H-89 were investigated on spatial memory acquisition in MWM. The rats were trained for 4 days; each day included one block of four trials. Post-training probe tests were performed on day 5 in acquisition test. For retention assessments, different animals were trained for 4 days and then infused (i.h.) with either DMSO, H-89, auraptene/H-89, resveratrol/H-89, or curcumin/H-89. The retention test was performed 48 h after the last training trial. The bilateral infusion of H-89 led to a significant impairment in spatial memory in acquisition and retention tests accompanied with a significant decrease in expressions of cAMP response-element binding (CREB) and pCREB proteins in hippocampus. Resveratrol and curcumin reversed the H-89-induced spatial memory acquisition and retention impairments with significant increases in both CREB and pCREB proteins expressions compared to H-89-treated animals. Auraptene showed significant effects in reversing H-89-induced impairments in spatial memory retention but not spatial memory acquisition.

Resveratrol alleviates early brain injury following subarachnoid hemorrhage: possible involvement of the AMPK/SIRT1/autophagy signaling pathway

Resveratrol (RSV) attenuates early brain injury (EBI) after subarachnoid hemorrhage (SAH). This study aimed to investigate whether the effects of RSV on SAH-induced EBI were mediated via the AMPK/SIRT1/autophagy pathway. A SAH rat model was established and oxyhemoglobin (Oxyhb)-induced primary cortical neurons were prepared to mimic SAH in vitro. The results showed that RSV significantly reduced microglia activation and the release of inflammatory cytokines, resulting in the alleviation of neurological behavior impairment, brain edema and neural apoptosis at 24 h post-SAH. However, RSV failed to ameliorate neurological deficits, brain edema and neural apoptosis when SAH injury lasted for 72 h. Additionally, at 24 h post-SAH, RSV-administered rats showed a significant increase in the LC3-II/I ratio and the phosphorylation state of AMPK and SIRT1 protein expression in brain tissues. Further in vitro studies revealed that RSV notably reduced the release of inflammatory cytokines and neural apoptosis in neurons at 24 post-Oxyhb, which was abolished by 3MA (an autophagy inhibitor) and Compound C (an AMPK inhibitor). Moreover, Compound C decreased LC3-II/I ratio and inhibited SIRT1 protein expression, whereas 3MA had no significant effects on AMPK/SIRT1-related proteins. In conclusion, the AMPK/SIRT1/autophagy pathway plays an important role in the alleviation of SAH-induced EBI by RSV.

The antioxidant resveratrol acts as a non-selective adenosine receptor agonist

Resveratrol (RSV) is a natural polyphenolic antioxidant with a proven protective role in several human diseases involving oxidative stress, although the molecular mechanism underlying this effect remains unclear. The present work tried to elucidate the molecular mechanism of RSV's role on signal transduction modulation. Our biochemical analysis, including radioligand binding, real time PCR, western blotting and adenylyl cyclase activity, and computational studies provide insights into the RSV binding pathway, kinetics and the most favored binding pose involving adenosine receptors, mainly A_2A subtype. In this study, we show that RSV target adenosine receptors (AdoRs), affecting gene expression, receptor levels, and the downstream adenylyl cyclase (AC)/PKA pathway. Our data demonstrate that RSV activates AdoRs. Moreover, RSV activate A_2A receptors by directly binding to the classical orthosteric binding site. Intriguingly, RSV-induced receptor activation can stimulate or inhibit AC activity depending on concentration and exposure time. Such subtle and multifaceted regulation of the AdoRs/AC/PKA pathway might contribute to the protective role of RSV. Our findings suggest that RSV molecular action is mediated, at least in part, by activation of adenosine receptors and create the opportunity to interrogate the therapeutic use of RSV in pathological conditions involving AdoRs, such as Alzheimer.

Signaling transduction regulated by 5-hydroxytryptamine 1A receptor and orexin receptor 2 heterodimers

As G-protein-coupled receptors (GPCRs), 5-hydroxytryptamine 1A receptor (5-HT1AR) and orexin receptor 2 (OX2R) regulate the levels of the cellular downstream molecules. The heterodimers of different GPCRs play important roles in various of neurological diseases. Moreover, 5-HT1AR and OX2R are involved in the pathogenesis of neurological diseases such as depression with deficiency of hippocampus plasticity. However, the direct interaction of the two receptors remains elusive. In the present study, we firstly demonstrated the heterodimer formation of 5-HT1AR and OX2R. Exchange protein directly activated by cAMP (Epac) cAMP bioluminescence resonance energy transfer (BRET) biosensor analysis revealed that the expression levels of cellular cAMP significantly increased in HEK293T cells transfected with the two receptors compared with the 5-HT1AR group. Additionally, the cellular level of calcium was upregulated robustly in HEK293T cells co-transfected with 5-HT1AR and OX2R group after agonist treatment. Furthermore, western blotting data showed that 5-HT1AR and OX2R heterodimer decreased the levels of phosphorylation of extracellular signal-regulated kinase (ERK) and cAMP-response element-binding protein (CREB). These results not only unraveled the formation of 5-HT1AR and OX2R heterodimer but also suggested that the heterodimer affected the downstream signaling pathway, which will provide new insights into the function of the two receptors in the brain.

Activation of c-Jun N-terminal kinase and p38 after cerebral ischemia upregulates cerebral sodium-glucose transporter type 1

Cerebral ischemic stress increases cerebral sodium-glucose transporter type 1 (SGLT-1). However, the mechanism by which cerebral ischemia leads to the up-regulation of SGLT-1 remains unclear. In peripheral tissue, the activation of mitogen-activated protein kinases (MAPKs) increases SGLT-1. MAPK pathways [c-Jun N-terminal kinase (JNK), p38 MAPK, and extracellular signal-regulated protein kinase (ERK)] are activated by cerebral ischemic stress. Therefore, we confirmed the involvement of MAPKs in the up-regulation of cerebral SGLT-1 after cerebral ischemia. Male ddY mice were subjected to middle cerebral artery occlusion (MCAO). Protein expression was assessed by western blotting. Mice received an intracerebroventricular (i.c.v.) injection of SP600125 (JNK inhibitor), SB203580 (p38 inhibitor), and PD98059 (MEK inhibitor) immediately after reperfusion. The infarction and behavioral abnormalities were assessed on days 1 and 3 after MCAO. The MAPK inhibitors suppressed the activation of JNK, p38, and ERK 3 h after MCAO. SP600125 and SB203580 administration ameliorated cerebral ischemic neuronal damage, whereas PD98059 administration exacerbated cerebral ischemic neuronal damage. SP600125 and SB203580 significantly suppressed the increase in SGLT-1 12 h after MCAO. PD98059 had no effect on SGLT-1 expression after MCAO. Our results indicate that the activation of JNK and p38 participate in the up-regulation of cerebral SGLT-1 after MCAO.

Pharmacogenetic modulation of STEP improves motor and cognitive function in a mouse model of Huntington's disease

Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by an expansion of a CAG repeat in the huntingtin (htt) gene, which results in an aberrant form of the protein (mhtt). This leads to motor and cognitive deficits associated with corticostriatal and hippocampal alterations. The levels of STriatal-Enriched protein tyrosine Phosphatase (STEP), a neural-specific tyrosine phosphatase that opposes the development of synaptic strengthening, are decreased in the striatum of HD patients and also in R6/1 mice, thereby contributing to the resistance to excitotoxicity described in this HD mouse model. Here, we aimed to analyze whether STEP inactivation plays a role in the pathophysiology of HD by investigating its effect on motor and cognitive impairment in the R6/1 mouse model of HD. We found that genetic deletion of STEP delayed the onset of motor dysfunction and prevented the appearance of cognitive deficits in R6/1 mice. This phenotype was accompanied by an increase in pERK1/2 levels, a delay in the decrease of striatal DARPP-32 levels and a reduction in the size of mhtt aggregates, both in the striatum and CA1 hippocampal region. We also found that acute pharmacological inhibition of STEP with TC-2153 improved cognitive function in R6/1 mice. In conclusion, our results show that deletion of STEP has a beneficial effect on motor coordination and cognition in a mouse model of HD suggesting that STEP inhibition could be a good therapeutic strategy in HD patients.

MicroRNA-150 contributes to ischemic stroke through its effect on cerebral cortical neuron survival and function by inhibiting ERK1/2 axis via Mal

Ischemic stroke, caused by the blockage of blood supply, is a major cause of death worldwide. For identifying potential candidates, we explored the effects microRNA-150 (miR-150) has on ischemic stroke and its underlying mechanism by developing a stable middle cerebral artery occlusion (MCAO) rat model. Gene expression microarray analysis was performed to screen differentially expressed genes associated with MCAO. We evaluated the expression of miR-150 and Mal and the status of ERK1/2 axis in the brain tissues of MCAO rats. Then the cerebral cortical neurons (CCNs) were obtained and introduced with elevated or suppressed miR-150 or silenced Mal to validate regulatory mechanisms for miR-150 governing Mal in vitro. The relationship between miR-150 and Mal was verified by dual luciferase reporter gene assay. Besides, cell growth and apoptosis of CCNs were detected by means of MTT assay and flow cytometry analyses. We identified Mal as a downregulated gene in MCAO, based on the microarray data of GSE16561. MiR-150 was over-expressed and negatively targeted Mal in the brain tissues obtained from MCAO rats and their CCNs. Increasing miR-150 blocked the ERK1/2 axis, resulting in an inhibited cell growth of CNNs but an enhanced apoptosis. Furthermore, MiR-150 inhibition was observed to have effects on CNNs as opposed to those inhibited by miR-150 promotion. The key findings of this study support the notion that miR-150 under-expression-mediated direct promotion of Mal protects CNN functions through the activation of the ERK1/2 axis, and underscore the concept that miR-150 may represent a novel pharmacological target for ischemic stroke intervention.

Role of Exosomes Derived from miR-133b Modified MSCs in an Experimental Rat Model of Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) has poor outcomes due to high mortality and morbidity, but until now, the effective treatments remain limited. MicroRNAs (miRNAs) are vital regulators of gene expression and demonstrated to be linked to the pathogenesis of various central nervous system (CNS) diseases. Exosomes are considered as cell-to-cell communication vectors and secreted largely by mesenchymal stromal cells (MSCs). The present study investigated the role of miR-133b delivered by exosomes secreted from MSCs to brain tissues in rats after ICH. An autologous arterial blood ICH model in adult male Sprague-Dawley (SD) rats was used in this study. At 72 h after transfection with miR-133b mimics in MSCs, miR-133b-modified MSC-derived exosomes were collected from medium of MSCs and then injected to rats via tail vein. The levels of miR-133b in secreted exosomes and brain tissues of rats in various groups and the levels of RhoA, phosphorylations of extracellular signal regulating kinase (ERK1/2), and cAMP response element-binding protein (CREB) were detected by real-time PCR and western blot analysis, respectively. The effects of miR-133b on neuronal apoptosis and degeneration were respectively evaluated by TUNEL and fluoro-jade B staining. The miR-133b levels were reduced in brain tissues of rats at 24 h and peaked at 72 h after ICH. At 24 h after miR-133b-modified exosome administration, the level of miR-133b was significantly increased, while the apoptotic and neurodegenerative neurons were obviously reduced in brain tissues after ICH. The results of western blot analysis showed that miR-133b modified exosomes treatment remarkably suppressed RhoA expression and activated ERK1/2/CREB in brain tissues after ICH. Collectively, our investigation suggested that exosomes derived from miR-133b modified MSCs exhibited neuroprotective role for anti-apoptotic effect of miR-133b mediating RhoA and ERK1/2/CREB in rats after ICH.

Effect of resveratrol and pterostilbene on aging and longevity

Over the past years, several studies have found that foods rich in polyphenols protect against age-related disease, such as atherosclerosis, cardiovascular disease, cancer, arthritis, cataracts, osteoporosis, type 2 diabetes (T2D), hypertension and Alzheimer's disease. Resveratrol and pterostilbene, the polyphenol found in grape and blueberries, have beneficial effects as anti-aging compounds through modulating the hallmarks of aging, including oxidative damage, inflammation, telomere attrition and cell senescence. In this review, we discuss the relationship between resveratrol and pterostilbene and possible aging biomarker, including oxidative stress, inflammation, and high-calorie diets. Moreover, we also discuss the positive effect of resveratrol and pterostilbene on lifespan, aged-related disease, and health maintenance. Furthermore, we summarize a variety of important mechanisms modulated by resveratrol and pterostilbene possibly involved in attenuating age-associated disorders. Overall, we describe resveratrol and pterostilbene potential for prevention or treatment of several age-related diseases by modulating age-related mechanisms. © 2017 BioFactors, 44(1):69-82, 2018.

Puerarin protects rat brain against ischemia/reperfusion injury by suppressing autophagy via the AMPK-mTOR-ULK1 signaling pathway

Puerarin suppresses autophagy to alleviate cerebral ischemia/reperfusion injury, and accumulating evidence indicates that the AMPK-mTOR signaling pathway regulates the activation of the autophagy pathway through the coordinated phosphorylation of ULK1. In this study, we investigated the mechanisms underlying the neuroprotective effect of puerarin and its role in modulating autophagy via the AMPK-mTOR-ULK1 signaling pathway in the rat middle cerebral artery occlusion model of cerebral ischemia/reperfusion injury. Rats were intraperitoneally injected with puerarin, 50 or 100 mg/kg, daily for 7 days. Then, 30 minutes after the final administration, rats were subjected to transient middle cerebral artery occlusion for 90 minutes. Then, after 24 hours of reperfusion, the Longa score and infarct volume were evaluated in each group. Autophagosome formation was observed by transmission electron microscopy. LC3, Beclin-1 p62, AMPK, mTOR and ULK1 protein expression levels were examined by immunofluorescence and western blot assay. Puerarin substantially reduced the Longa score and infarct volume, and it lessened autophagosome formation in the hippocampal CA1 area following cerebral ischemia/reperfusion injury in a dose-dependent manner. Pretreatment with puerarin (50 or 100 mg/kg) reduced Beclin-1 expression and the LC3-II/LC3-I ratio, as well as p-AMPK and pS317-ULK1 levels. In comparison, it increased p62 expression. Furthermore, puerarin at 100 mg/kg dramatically increased the levels of p-mTOR and pS757-ULK1 in the hippocampus on the ischemic side. Our findings suggest that puerarin alleviates autophagy by activating the APMK-mTOR-ULK1 signaling pathway. Thus, puerarin might have therapeutic potential for treating cerebral ischemia/reperfusion injury.

Angelica sinensis Exerts Angiogenic and Anti-apoptotic Effects Against Cerebral Ischemia–Reperfusion Injury by Activating p38MAPK/HIF-1α/VEGF-A Signaling in Rats

This study evaluated the effects of Angelica sinensis extract [Dang Gui (DG)] administered before 60[Formula: see text]min of middle cerebral artery occlusion followed by 3[Formula: see text]d of reperfusion and investigated the involvement of mitogen-activated protein kinase (MAPK)/hypoxia-inducible factor (HIF)-1[Formula: see text] signaling in the cortical ischemic penumbra. DG was intraperitoneally administered at a dose of 0.25[Formula: see text]g/kg (DG-0.25g), 0.5[Formula: see text]g/kg (DG-0.5g), or 1[Formula: see text]g/kg (DG-1g) 30[Formula: see text]min before the onset of cerebral ischemia. Our study results revealed that DG-0.5g and DG-1g pretreatment effectively attenuated cerebral infarct and improved neurological deficits. DG-0.5g and DG-1g pretreatment significantly downregulated glial fibrillary acidic protein (GFAP), cytochrome c, and cleaved caspase-3 expression and upregulated phospho-p38 MAPK (p-p38 MAPK)/p38 MAPK, phospho-cAMP response element-binding protein (p-CREB)/CREB, cytosolic and mitochondrial phospho-Bad (p-Bad)/Bad ratios, and HIF-1[Formula: see text], vascular endothelial growth factor-A (VEGF-A), phospho-90 kDa ribosomal S6 kinase (p-p90RSK), and von Willebrand factor (vWF) expression in the cortical ischemic penumbra. Pretreatment with SB203580, a p38 MAPK inhibitor, dramatically abrogated the upregulating effects of DG-1g on p-p38 MAPK/p38 MAPK, p-CREB/CREB, and p-Bad/Bad ratios and HIF-1[Formula: see text], VEGF-A, and vWF expression and the downregulating effects of DG-1g on GFAP, cytochrome c, cleaved caspase-3, and cerebral infarction. DG-0.5g and DG-1g pretreatment provided neuroprotective effects against astrocyte-mediated cerebral infarction by activating angiogenic and anti-apoptotic signaling. Moreover, the angiogenic and anti-apoptotic effects of DG pretreatment can be attributed to the activation of p38 MAPK/HIF-1[Formula: see text]/VEGF-A/vWF signaling and p38 MAPK/HIF-1[Formula: see text]/VEGF-A/p-Bad-related regulation of cytochrome c/caspase-3 signaling, respectively, in the cortical ischemic penumbra 3[Formula: see text]d after reperfusion.

Clonidine preconditioning improved cerebral ischemia-induced learning and memory deficits in rats via ERK1/2-CREB/ NF-κB-NR2B pathway

Clonidine, a classical α-2 adrenergic agonists, has been shown to antagonize brain damage caused by hypoxia, cerebral ischemia and excitotoxicity and reduce cerebral infarction volume in recent studies. We herein investigate the regulatory effect and possible underlying mechanism of clonidine on learning and memory in rats with cerebral ischemia. The cerebral ischemia rat model was established by right middle cerebral artery occlusion for 2h and reperfusion for 28 days. Drugs were administrated to the rats for consecutive 7 days intraperitoneally and once again on the day of surgery. The learning and memory in rats was assayed by Morris water maze. Moreover, protein expression levels of NMDAR2B (NR2B)/ phosphor - NR2B, ERK1/2/phosphor- ERK1/2, CREB/phosphor-CREB and NF-κB/phosphor-NF-κB in the cortex and hippocampus of the rats were assayed by western blotting. Our results demonstrated that clonidine treatment significantly abrogated the negative effect induced by cerebral ischemia on the learning and memory in the rats. In the Western blotting assay, clonidine treatment led to significant up-regulation of the expression level of NR2B and Phospho-NR2B in the hippocampus of the rats when compared with the cerebral ischemia group. Furthermore, clonidine also significantly decreased the protein expression levels of ERK1/2, Phospho-ERK1/2, CREB, Phospho-CREB and Phospho-NF-κB in the hippocampus of the rats when compared with the cerebral ischemia group. In conclusion, clonidine could improve the learning and memory ability of rats with cerebral ischemia, and NR2B, ERK1/2, CREB, NF-κB were involved in this effect.

Changes in the expression level of MAPK pathway components induced by monosodium glutamate-administration produce neuronal death in the hippocampus from neonatal rats

Excessive Glutamate (Glu) release may trigger excitotoxic cellular death by the activation of intracellular signaling pathways that transduce extracellular signals to the cell nucleus, which determines the onset of a death program. One such signaling pathway is the mitogen-activated protein kinases (MAPK), which is involved in both survival and cell death. Experimental evidences from the use of specific inhibitors supports the participation of some MAPK pathway components in the excitotoxicity mechanism, but the complete process of this activation, which terminates in cell damage and death, is not clearly understood. The present work, we investigated the changes in the expression level of some MAPK-pathway components in hippocampal excitotoxic cell death in the neonatal rats using an experimental model of subcutaneous monosodium glutamate (MSG) administration on postnatal days (PD) 1, 3, 5 and 7. Data were collected at different ages through PD 14. Cell viability was evaluated using fluorescein diacetate mixed with propidium iodide (FDA-PI), and the Nissl-staining technique was used to evaluate histological damage. Transcriptional changes were also investigated in 98 components of the MAPK pathway that are associated with cell damage. These results are an evidence of that repetitive use of MSG, in neonatal rats, induces cell damage-associated transcriptional changes of MAPK components, that might reflect a differential stage of both biochemical and molecular brain maturation. This work also suggests that some of the proteins evaluated such as phosphorylated retinoblastoma (pRb) protein, which was up-regulated, could regulate the response to excitotoxic through modulation of the process of re-entry into the cell cycle in the hippocampus of rats treated with MSG.