w007B protects brain against ischemia-reperfusion injury in rats through inhibiting inflammation, apoptosis and autophagy

Hydrogen Sulfide Protects against Rat Ischemic Brain Injury by Promoting RhoA Phosphorylation at Serine 188

The protective role of hydrogen sulfide against cerebral ischemia-reperfusion injury involves the inhibition of the RhoA-/Rho-associated coiled-coil kinase (ROCK) pathway. However, the specific mechanism remains elusive. This study investigates the impact of hydrogen sulfide on RhoA phosphorylation at serine 188 (Ser188) in vivo, aiming to test the hypothesis that hydrogen sulfide exerts neuroprotection by enhancing RhoA phosphorylation at Ser188, subsequently inhibiting the RhoA/ROCK pathway. Recombinant RhoAwild-pEGFP-N1 and RhoAS188A-pEGFP-N1 plasmids were constructed and administered via stereotaxic injection into the rat hippocampus. A rat global cerebral ischemia-reperfusion model was induced by bilateral carotid artery ligation to elucidate the neuroprotective mechanisms of hydrogen sulfide. Both RhoAwild-pEGFP-N1 and RhoAS188A-pEGFP-N1 plasmids expressed RhoAwild and RhoAS188A proteins, respectively, in rat hippocampal tissues, alongside the intrinsic RhoA protein. Systemic administration of the exogenous hydrogen sulfide donor sodium hydrosulfide led to an increase in Ser188 phosphorylation of transfected RhoAwild and intrinsic RhoA protein within the hippocampus. However, this effect was not observed in tissues transfected with RhoAS188A. Sodium hydrosulfide-mediated RhoA phosphorylation correlated with decreased RhoA and ROCK2 activity in rat hippocampal tissues. Furthermore, sodium hydrosulfide administration reduced cerebral ischemia-reperfusion-induced neuronal damage and apoptosis in rat hippocampal tissues transfected with RhoAwild. However, this neuroprotective effect was attenuated in rats transfected with RhoAS188A. These findings suggest that the neuroprotective mechanism of hydrogen sulfide against cerebral ischemia/reperfusion injury involves increased RhoA phosphorylation at Ser188. Promoting this phosphorylation may represent a potential intrinsic therapeutic target for ischemic stroke.

Neuropharmacological potential of honokiol and its derivatives from Chinese herb Magnolia species: understandings from therapeutic viewpoint

Honokiol is a neolignan biphenol found in aerial parts of the Magnolia plant species. The Magnolia plant species traditionally belong to China and have been used for centuries to treat many pathological conditions. Honokiol mitigates the severity of several pathological conditions and has the potential to work as an anti-inflammatory, anti-angiogenic, anticancer, antioxidant, and neurotherapeutic agent. It has a long history of being employed in the healthcare practices of Southeast Asia, but in recent years, a greater scope of research has been conducted on it. Plenty of experimental evidence suggests it could be beneficial as a neuroprotective bioactive molecule. Honokiol has several pharmacological effects, leading to its exploration as a potential therapy for neurological diseases (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), cerebral ischemia, anxiety, depression, spinal cord injury, and so on. So, based on the previous experimentation reports, our goal is to discuss the neuroprotective properties of honokiol. Besides, honokiol derivatives have been highlighted recently as possible therapeutic options for NDs. So, this review focuses on honokiol's neurotherapeutic actions and toxicological profile to determine their safety and potential use in neurotherapeutics.

Melatonin Attenuates Cerebral Ischemia/Reperfusion Injury through Inducing Autophagy

INTRODUCTION

The aim of this study was to investigate how melatonin administration for 3 days or 7 days following cerebral ischemia (CI) injury would affect autophagy and, therefore, survival in neurons of the penumbra region. Moreover, it was also aimed at determining how this melatonin treatment would affect the neurological deficit score and rotarod and adhesive removal test durations.

METHODS

Focal CI (90 min) was achieved in a total of 105 rats utilizing a middle cerebral artery occlusion model. After the start of reperfusion, the groups were treated with melatonin (10 mg/kg/day) for 3 days or 7 days. In all groups, neurological deficit scoring, rotarod, and adhesive removal tests were executed during reperfusion. Infarct areas were determined by TTC (2,3,5-triphenyltetrazolium chloride) staining at the end of the 3rd and 7th days of reperfusion. Beclin-1, LC3, p62, and caspase-3 protein levels were assessed using Western blot and immunofluorescence methods in the brain tissues. Moreover, penumbra areas were evaluated by transmission electron microscopy (TEM).

RESULTS

Following CI, it was observed that melatonin treatment improved the rotarod and adhesive removal test durations from day 5 and reduced the infarct area after CI. It also induced autophagic proteins Beclin-1, LC3, and p62 and suppressed the apoptotic protein cleaved caspase-3. According to TEM findings, melatonin treatment partially reduced the damage in neurons after CI.

CONCLUSION

Melatonin treatment following CI reduced the infarct area and induced the autophagic proteins Beclin-1, LC3, and p62 by inhibiting the apoptotic caspase-3 protein. The functional reflection of melatonin treatment on neurological test scores was became significant from the 5th day onward.

Neurointerventional infusion of hemoglobin oxygen carrier prevents brain damage from acute cerebral ischemia in rats

Aim

To save brain cells in acute cerebral infarction by injecting hemoglobin oxygen carrier (HBOC) into the blood vessel blockage of the cerebral infarction site through a microcatheter.

Methods

120 male rats were divided into four groups: control (CTRL), ischemia (I), ischemia + low perfusion (I + LP), and ischemia + high perfusion (I + HP). Perfusion groups (ischemia, I + LP, and I + HP) underwent MCAO surgery with intraluminal monofilament. These groups were subdivided into 6 h, 12 h, and 24 h (n = 10/group). RT-PCR, Western-Blot, immunohistochemistry, and apoptosis assays were used to detect apoptosis, hypoxia range and extent, and ischemia.

Results

Compared with the I group, the neurological deficit sign scores of the I + HP group were statistically significant at 12 h. Compared with the I group, the neurological deficit sign scores of the I + LP group and the I + HP group were statistically significant at 24 h. At all time points, compared with the I group and the I + LP group, Caspase-3, HIF-1α, and Cytochrome C protein levels were significantly decreased in the I + HP group. Bcl-2 and BAX mRNA levels were also significantly decreased in the same group. TNF-α, IL-6, and IL-1β cytokines were significantly decreased in the I + HP group as well. The infarct size of rats in the I + HP group was smaller than that of the I + LP group, which was smaller than ischemia alone. Time of perfusion had an obvious effect as infarct size was smaller with longer perfusion. The number of Nissl stained cells in the I + HP group was increased compared with the ischemia and the I + LP group, and was proportional to the time of perfusion.

Conclusion

Time- and rate-controlled perfusion of HBOC to acutely occluded cerebral vascular regions through microcatheters can effectively protect ischemic brain tissue in rats.

Neuroprotective Potency of Neolignans in Magnolia officinalis Cortex Against Brain Disorders

In recent years, neurological diseases including Alzheimer’s disease, Parkinson’s disease and stroke are one of the main causes of death in the world. At the same time, the incidence of psychiatric disorders including depression and anxiety has been increasing. Accumulating elderly and stressed people suffer from these brain disorders, which is undoubtedly a huge burden on the modern aging society. Neolignans, the main active ingredients in Magnolia officinalis cortex, were reported to have neuroprotective effects. In addition, the key bioactive ingredients of neolignans, magnolol (1) and honokiol (2), were proved to prevent and treat neurological diseases and psychiatric disorders by protecting nerve cells and brain microvascular endothelial cells (BMECs). Furthermore, neolignans played a role in protecting nerve cells via regulation of neuronal function, suppression of neurotoxicity, etc. This review summarizes the neuroprotective effect, primary mechanisms of the leading neolignans and provides new prospects for the treatment of brain disorders in the future.

Inhibition of intracellular proton-sensitive Ca2+-permeable TRPV3 channels protects against ischemic brain injury

Ischemic brain stroke is pathologically characterized by tissue acidosis, sustained calcium entry and progressive cell death. Previous studies focusing on antagonizing N-methyl-d-aspartate (NMDA) receptors have failed to translate any clinical benefits, suggesting a non-NMDA mechanism involved in the sustained injury after stroke. Here, we report that inhibition of intracellular proton-sensitive Ca²⁺-permeable transient receptor potential vanilloid 3 (TRPV3) channel protects against cerebral ischemia/reperfusion (I/R) injury. TRPV3 expression is upregulated in mice subjected to cerebral I/R injury. Silencing of TRPV3 reduces intrinsic neuronal excitability, excitatory synaptic transmissions, and also attenuates cerebral I/R injury in mouse model of transient middle cerebral artery occlusion (tMCAO). Conversely, overexpressing or re-expressing TRPV3 increases neuronal excitability, excitatory synaptic transmissions and aggravates cerebral I/R injury. Furthermore, specific inhibition of TRPV3 by natural forsythoside B decreases neural excitability and attenuates cerebral I/R injury. Taken together, our findings for the first time reveal a causative role of neuronal TRPV3 channel in progressive cell death after stroke, and blocking overactive TRPV3 channel may provide therapeutic potential for ischemic brain injury.

Honokiol Provides Cardioprotection from Myocardial Ischemia/Reperfusion Injury (MI/RI) by Inhibiting Mitochondrial Apoptosis via the PI3K/AKT Signaling Pathway

Background

Myocardial injury refers to a major complication that occurs in myocardial ischemia/reperfusion injury (MI/RI). Honokiol is a well-recognized active compound extracted from the traditional Chinese herb known as Magnolia officinalis and is utilized in treating different vascular diseases. This research is aimed at examining whether Honokiol might alleviate myocardial injury in an MI/RI model.

Methods

Seventy-eight male C57BL/6 mice were categorized randomly into three cohorts including the Sham operation (Sham) cohort, the MI/RI cohort (Con), and the Honokiol cohort (n = 26 for each cohort). The mice in the Honokiol cohort were treated with Honokiol before MI/RI surgery (0.2 mg/kg/day for 14 days, intraperitoneal), while the mice in the Con cohort were given an intraperitoneal injection with an equivalent volume of vehicle (DMSO) daily in 14 days prior to exposure to MI/RI. After the surgery, creatine kinase- (CK-) MB and cardiac troponin T (cTnT) levels, as well as the infarct area, were measured to assess the degree of myocardial damage. Apoptotic levels were detected using terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining. Electron microscopy was utilized to identify mitochondrial damage. Lastly, the expression levels of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), cleaved caspase-9, cytochrome C (Cyt-C), B cell lymphoma/leukemia-2 (Bcl-2), B cell lymphoma/leukemia-2 associated X (Bax), AKT, p-AKT, PI3K, and p-PI3K were analyzed utilizing western blotting.

Results

Honokiol can reduce the MI/RI-induced cTnT and CK-MB levels, apoptosis index, and mitochondrial swelling in cardiomyocytes via activating the PI3K/AKT signaling pathway.

Conclusion

Honokiol provides cardiac protection from MI/RI by suppressing mitochondrial apoptosis through the PI3K/AKT signaling pathway.

Neuroprotective effects of long noncoding RNAs involved in ischemic postconditioning after ischemic stroke

During acute reperfusion, the expression profiles of long noncoding RNAs in adult rats with focal cerebral ischemia undergo broad changes. However, whether long noncoding RNAs are involved in neuroprotective effects following focal ischemic stroke in rats remains unclear. In this study, RNA isolation and library preparation was performed for long noncoding RNA sequencing, followed by determining the coding potential of identified long noncoding RNAs and target gene prediction. Differential expression analysis, long noncoding RNA functional enrichment analysis, and co-expression network analysis were performed comparing ischemic rats with and without ischemic postconditioning rats. Rats were subjected to ischemic postconditioning via the brief and repeated occlusion of the middle cerebral artery or femoral artery. Quantitative real-time reverse transcription-polymerase chain reaction was used to detect the expression levels of differentially expressed long noncoding RNAs after ischemic postconditioning in a rat model of ischemic stroke. The results showed that ischemic postconditioning greatly affected the expression profile of long noncoding RNAs and mRNAs in the brains of rats that underwent ischemic stroke. The predicted target genes of some of the identified long noncoding RNAs (cis targets) were related to the cellular response to ischemia and stress, cytokine signal transduction, inflammation, and apoptosis signal transduction pathways. In addition, 15 significantly differentially expressed long noncoding RNAs were identified in the brains of rats subjected to ischemic postconditioning. Nine candidate long noncoding RNAs that may be related to ischemic postconditioning were identified by a long noncoding RNA expression profile and long noncoding RNA-mRNA co-expression network analysis. Expression levels were verified by quantitative real-time reverse transcription-polymerase chain reaction. These results suggested that the identified long noncoding RNAs may be involved in the neuroprotective effects associated with ischemic postconditioning following ischemic stroke. The experimental animal procedures were approved by the Animal Experiment Ethics Committee of Kunming Medical University (approval No. KMMU2018018) in January 2018.

Thrombin aggravates hypoxia/reoxygenation injury of astrocytes by activating the autophagy pathway mediated by SPRED2

Autophagy plays an important role in ischemia/reperfusion brain injury, however, the signaling pathways involved in cell autophagy are not fully understood. The present study aimed to investigate the roles and molecular mechanisms of thrombin and Sprouty-related EVH1 domain-2 (SPRED2) on autophagy in hypoxia/reoxygenation (H/R) induced astrocytes. Reverse transcription-quantitative PCR and western blot analyses were performed to detect the expression levels of thrombin and SPRED2. Western blot analysis was also performed to detect the protein expression levels of Beclin 1, microtubule-associated protein light chain 3 (LC3)-II and LC3-I. The MTT assay was performed to assess cell viability, while ELISA was performed to determine the supernatant levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α. The results demonstrated that the effects of H/R induction on inflammatory factor secretion, oxidative stress, autophagy and cell viability in astrocytes were aggravated by thrombin, the effects of which were reversed following SPRED2 knockdown. Taken together, the results of the present study suggest that thrombin aggravates H/R injury in astrocytes by activating the SPRED2-mediated autophagy.

Crosstalk Between Autophagy and Ferroptosis and Its Putative Role in Ischemic Stroke

Autophagy is a conserved process to maintains homeostasis via the degradation of toxic cell contents, which can either promote cell survival or accelerate cellular demise. Ferroptosis is a recently discovered iron-dependent cell death pathway associated with the accumulation of lethal reactive lipid species. In the past few years, an increasing number of studies have suggested the crosstalk between autophagy and ferroptosis. Ischemic stroke is a complex brain disease regulated by several cell death pathways, including autophagy and ferroptosis. However, the potential links between autophagy and ferroptosis in ischemic stroke have not yet been explored. In this review, we briefly overview the mechanisms of ferroptosis and autophagy, as well as their possible connections in ischemic stroke. The elucidation of crosstalk between different cell death pathways may provide insight into new future ischemic stroke therapies.

Curcumin Suppresses Apoptosis and Inflammation in Hypoxia/Reperfusion-Exposed Neurons via Wnt Signaling Pathway

BACKGROUND Cerebral ischemia/reperfusion (I/R) injury contributes to mortality and morbidity in preterm infants. Curcumin has been shown to exert neuro-protective effects in the central nervous system (CNS). The aim of this study was to investigate the neuro-protective activity of curcumin and the possible underlying molecular mechanisms. MATERIAL AND METHODS A hypoxia/reoxygenation (H/R) protocol was used to simulate I/R injury in vitro. Isolated neonatal neurons were pre-treated with curcumin at serially diluted concentrations and exposed to H/R injury. Cell viability and apoptosis were assessed by MTT and flow cytometry, respectively. Contents of TNFa and IL6 in supernatant of cell culture medium were detected by ELISA. Protein expression, phosphorylation, and nuclear translocation levels were studied by Western blotting. RESULTS H/R reduced cell viability and increased apoptosis of neurons. H/R significantly increased Wnt5a expression, JNK1 phosphorylation, and NF-kappaB nuclear translocation. Moreover, expression levels of cleaved caspase3, TNFalpha, and IL6 were elevated in H/R-exposed neurons. Curcumin pre-treatment significantly increased cell viability and inhibited apoptosis of neurons exposed to H/R, in a concentration-dependent manner. Moreover, curcumin pre-treatment significantly decreased expression levels of Wnt5a, IL6, TNFalpha, and phosphorylation level of JNK1, as well as the nuclear translocation level of NF-kappaB in H/R-exposed neurons, in a concentration-dependent manner. CONCLUSIONS Curcumin exerted neuro-protective effects against H/R-induced neuron apoptosis and inflammation by inhibiting activation of the Wnt/JNK1 signaling pathway.

Autophagy and Ischemic Stroke

Ischemic stroke refers to brain tissue ischemia, hypoxic necrosis, and brain softening caused by the interruption of the blood supply to the brain without adequate collateral circulation, thus resulting in neurological symptoms. Autophagy is activated in various cell types in the brain, such as neurons, glial cells, and microvascular cells, upon ischemic stroke. Autophagy efflux injury plays an important role in this pathologic process. This chapter outlines the induction of basal autophagy, autophagy in neurons, and the crosstalk between autophagy, necrosis, and apoptosis that contributes to ischemic stroke. We will highlight the interactions between autophagy, oxidative stress, endoplasmic reticulum stress, and mitochondrial dysfunction, and the role of autophagy in ischemic stroke. We will also review the recent advances in the understanding of the involvement of autophagy in the pathological process of cerebral ischemic preconditioning, periconditioning, and postconditioning.

Magnolol exhibits anti-inflammatory and neuroprotective effects in a rat model of intracerebral haemorrhage

Intracerebral haemorrhage (ICH) induces inflammation, which can cause severe secondary injury. Recent evidence has suggested that magnolol (MG) has a protective effect against ischaemic stroke through the inhibition of inflammation. However, the anti-inflammatory effect of MG in intracerebral haemorrhage (ICH) remains unclear. Here, we report that the protective effect of MG in a rat model of ICH can be achieved by anti-inflammatory processes. We found that MG administration significantly reduced the brain water content, restored the blood-brain barrier (BBB) and subsequently attenuated neurological deficits via decreasing the activation of glial cells, decreasing the infiltration of neutrophils and reducing the production of pro-inflammation factors (IL-1β, TNF-α and MMP-9) in a rat model of ICH. These results suggest that MG reduced inflammatory injury and improved neurological outcomes in ICH model.

FoxO3 transcription factor promotes autophagy after transient cerebral ischemia/reperfusion

Aim: Autophagy was activated after cerebral ischemia reperfusion (I/R) injury. However, the molecular mechanisms underlying regulation of autophagy in cerebral I/R injury were not completely understood. Studies reported that Forked-box class O (FoxO) transcription factors involved in autophagy and might be the regulator of autophagy in multiple cells. In this study, we investigated the effects of FoxO3 on regulating autophagy after cerebral I/R injury. Materials and methods: Rats were subjected to MCAO for 2 h and reperfusion for different times, western blot was used to examine the expression of p-FoxO3, FoxO3 and the autophagic marker LC3 and Beclin-1 in penumbral region. Then rats were injected with WT-FoxO3 or TM-FoxO3 adenovirus by lateral cerebral ventricle to increase the function of FoxO3, western blot was used to examine the expression of LC3 and Beclin-1 in penumbral region. TTC and HE staining were used to evaluate the effects of increased FoxO3 activation on I/R induced brain damage. Results: Our studies showed that I/R injury resulted in induction of autophagy in penumbral brain tissue with concomitant dephosphorylation of FoxO3, consistent with increased activity of nuclear FoxO3 transcription factor. Increased FoxO3 activation led to autophagy significantly increased and had a protective effects on I/R injury. Conclusion: These data revealed an important role of FoxO3 in regulating autophagy in brain, and provided a new approach for further prevention and treatment of cerebral ischemia.

Comparison between the effect of human Wharton's jelly-derived mesenchymal stem cells and levetiracetam on brain infarcts in rats

BACKGROUND

Stroke represents one of the major causes of death worldwide. Neuroprotection remains an important goal of stroke therapy. Stem cell therapeutic effect is attributed to the neuroprotective effect and the regulation of the oxidant stress. Levetiracetam (LEV), a second-generation antiepileptic drug, was reported to confer neuronal protection after cerebral ischemia reperfusion.

AIM

To investigate the effect of human Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) and LEV on the size of brain infarcts, the histological structure, the neurotrophic, and the antioxidant gene expression in middle cerebral artery occlusion in rats.

METHOD

The rats were divided into five equal groups of 12 rats each as follows. Sham control group: received phosphate-buffered saline (PBS); ischemia/reperfusion (I/R) group: received PBS before ligation; stem cell-treated group: the animal received MSCs before ligation; LEV-treated group: the animal received LEV before occlusion; combined group: the animals received both MSCs and LEV before occlusion. Hematoxylin and eosin staining was performed to study the histological structure of the brain. Real-time polymerase chain reaction (RT-PCR) was performed to assess gene expression.

RESULTS

Both MSCs and LEV improved memory and learning in the treated groups compared with I/R group. Significant reduction of the infarct size in WJ-MSC- or LEV-treated groups when compared with untreated ones was found. By RT-PCR, a significant decrease of the expression values of glial-derived neurotrophic factor (GDNF), brain-derived neurotrophic factor (BDNF), phosphatidylethanolamine binding protein 1 (PEBP1), and copper-zinc SOD (Cu/ZnSOD) genes and a significant increase of pro-oxidant iNOS gene in the I/R rats compared with the sham group was detected. There was a significant increase in the expression values of GDNF, BDNF, PEBP1, and Cu/ZnSOD genes in both treated groups when compared with the I/R group. Rats treated with WJ-MSCs showed better results than rats treated with LEV. Finally, the combined use of LEV and WJ-MSCs was the most effective regimen as regard infarction volume and functional learning and memory tests.

CONCLUSION

In the brain ischemia model, combined WJ-MSCs and LEV have demonstrated striking protective effects in brain infarction by the modulation of the oxidant status and neuroprotective effect.

Role of Myeloid Lineage Cell Autophagy in Ischemic Brain Injury

BACKGROUND AND PURPOSE

Inflammatory cells play a significant role in secondary injury after ischemic stroke. Recent studies have suggested that a lack of autophagy in myeloid cells causes augmented proinflammatory cytokine release and prolonged inflammation after tissue injury. In this study, we investigated the roles of myeloid cell autophagy in ischemic brain injury.

METHODS

Focal cerebral ischemia was induced via transient middle cerebral artery occlusion in mice with autophagy-deficient myeloid lineage cells (Atg5flox/flox LysMCre+) and in their littermate controls (Atg5flox/flox). Infarct volume, neurological function, inflammatory cell infiltration, and proinflammatory cytokine expression levels were evaluated.

RESULTS

Mice lacking autophagy in myeloid lineage cells had a lower survival rate for 14 days than control mice (20% versus 70%; P<0.05). Although there was no difference in infarct volume at 12 hours between the 2 groups, mice lacking autophagy in myeloid lineage cells had larger infarct volumes at later time points (3 and 7 days after reperfusion) with worse neurological deficit scores and lower grip test scores. There were a higher number of ionized calcium binding adaptor molecule 1-positive cells and cells expressing M1 marker CD16/32 in mice lacking autophagy in myeloid cells at the later time points. Moreover, these mice had higher expression levels of proinflammatory cytokines at later time points; however, there was no difference in ionized calcium binding adaptor molecule 1-positive cells or mRNA levels of proinflammatory cytokines at the earlier time point (12 hours after reperfusion).

CONCLUSIONS

These data suggest that the lack of myeloid cell autophagy aggravates secondary injury by augmenting and prolonging inflammation after ischemic stroke without affecting the initial injury.

Honokiol Ameliorates Myocardial Ischemia/Reperfusion Injury in Type 1 Diabetic Rats by Reducing Oxidative Stress and Apoptosis through Activating the SIRT1-Nrf2 Signaling Pathway

Reducing oxidative stress is a crucial therapeutic strategy for ameliorating diabetic myocardial ischemia/reperfusion (MI/R) injury. Honokiol (HKL) acts as an effective cardioprotective agent for its strong antioxidative activity. However, its roles and underlying mechanisms against MI/R injury in type 1 diabetes (T1D) remain unknown. Since SIRT1 and Nrf2 are pivotal regulators in diabetes mellitus patients suffering from MI/R injury, we hypothesized that HKL ameliorates diabetic MI/R injury via the SIRT1-Nrf2 signaling pathway. Streptozotocin-induced T1D rats and high-glucose-treated H9c2 cells were exposed to HKL, with or without administration of the SIRT1 inhibitor EX527, SIRT1 siRNA, or Nrf2 siRNA, and then subjected to I/R operation. We found that HKL markedly improved the postischemic cardiac function, decreased the infarct size, reduced the myocardial apoptosis, and diminished the reactive oxygen species generation. Intriguingly, HKL remarkably activated SIRT1 signaling, enhanced Nrf2 nuclear translocation, increased antioxidative signaling, and decreased apoptotic signaling. However, these effects were largely abolished by EX527 or SIRT1 siRNA. Additionally, our cellular experiments showed that Nrf2 siRNA blunted the cytoprotective effects of HKL, without affecting SIRT1 expression and activity. Collectively, these novel findings indicate that HKL abates MI/R injury in T1D by ameliorating myocardial oxidative damage and apoptosis via the SIRT1-Nrf2 signaling pathway.

Effect of magnolol on cerebral injury and blood brain barrier dysfunction induced by ischemia-reperfusion in vivo and in vitro

Magnolol, a neolignan compound isolated from traditional Chinese medicine Magnolia officinalis, has a potentially therapeutic influence on ischemic stroke. Previous studies have demonstrated that cerebral ischemia-reperfusion (I-R) and blood-brain barrier (BBB) are involved in the pathogeneses of stroke. Therefore, in vivo and in vitro studies were designed to investigate the effects of magnolol on I-R-induced neural injury and BBB dysfunction. In cerebral I-R model of mice, cerebral infarct volumes, brain water content, and the exudation of Evans blue were significantly reduced by intravenous injection with magnolol at the doses of 1.4, 7.0, and 35.0 μg/kg. When primary cultured microglial cells were treated with 1 μg/ml lipopolysaccharide (LPS) plus increasing concentrations of magnolol, ranging from 0.01 to 10 μmol/L, magnolol could statistically inhibit LPS-induced NO release, TNF-α secretion, and expression of p65 subunit of NF-κB in the nucleus of microglial cells. In the media of brain microvascular endothelial cells (BMECs), oxygen and glucose deprivation-reperfusion (OGD-R) could remarkably lead to the elevation of TNF-α and IL-1β levels, while magnolol evidently reversed these effects. In BBB model in vitro, magnolol dose- and time-dependently declined BBB hyperpermeability induced by oxygen and glucose deprivation (OGD), OGD-R, and ephrin-A1 treatment. More importantly, magnolol could obviously inhibit phosphorylation of EphA2 (p-EphA2) not only in ephrin-A1-treated BMECs but also in cerebral I-R model of mice. In contrast to p-EphA2, magnolol significantly increased ZO-1 and occludin levels in BMECs subjected to OGD. Taken together, magnolol can protect neural damage from cerebral ischemia- and OGD-reperfusion, which may be associated with suppressing cerebral inflammation and improving BBB function.

Simulated ischemia/reperfusion-induced p65-Beclin 1-dependent autophagic cell death in human umbilical vein endothelial cells

Myocardial ischemia/reperfusion (I/R) injury detrimentally alters the prognosis of patients undergoing revascularization after acute myocardial infarction. Our previous study demonstrated that NF-κB-induced autophagy plays a detrimental role in cardiac I/R injury using a rabbit myocardial I/R model. In this study, we sought to explore the specific mechanism of this autophagy-mediated cell damage in an in vitro simulated ischemia/reperfusion (sI/R) model using human umbilical vein endothelial cells. Our current study demonstrates that simulated I/R induces autophagy in a p65-Beclin 1-dependent manner, which can be suppressed with the inhibition of NF-κB. Furthermore, rapamycin which promotes autophagy, exacerbates sI/R-induced cell death. While 3-methyladenine rescues cell damage. Our data thus suggest that I/R promotes NF-κB p65 activity mediated Beclin 1-mediated autophagic flux, thereby exacerbating myocardial injury.

Electroacupuncture Ameliorates Cerebral Ischemia-Reperfusion Injury by Regulation of Autophagy and Apoptosis

Background. The therapeutic mechanisms of cerebral ischemia treatment by acupuncture are yet not well addressed. Objective. We investigated the effects of electroacupuncture (EA) at GV26 observing the expression of autophagy-related proteins Beclin-1 and LC3B and proportion of apoptotic cells and Bcl-2 positive cells in MCAO/R model rats. Methods. Sprague-Dawley (SD) male rats were randomly assigned to 7 groups: model groups (M6h, M24h, and M72h), EA treatment groups (T6h, T24h, and T72h), and sham operation group (S). Neurological deficit and cerebral infarction volume were measured to assess the improvement effect, while the expression of Beclin-1 and LC3B and proportion of Tunel-positive and Bcl-2 positive cells were examined to explore EA effect on autophagy and apoptosis. Results. EA significantly decreased neurological deficit scores and the volume of cerebral infarction. Beclin-1 was significantly decreased in T24h, while LC3B-II/LC3B-I ratio markedly reduced in 6th hour. EA groups markedly reduced the number of Tunel positive cells, especially in T24h. Meanwhile, the number of Bcl-2 positive cells obviously increased after EA treatment, especially in T6h and T24h. Conclusions. The alleviation of inadequate autophagy and apoptosis may be a key mechanism involved in the reflex regulation of EA at GV26 to treat cerebral ischemia.

Hydrogen-Rich Saline Attenuates Acute Kidney Injury After Liver Transplantation via Activating p53-Mediated Autophagy

BACKGROUND

Acute kidney injury (AKI) impacts the survival of liver transplant recipients severely. To date, the related mechanism and effective therapy have not been rigorously explored. The present study aimed to explore the role of p53-mediated autophagy in the protective effect of hydrogen-rich saline (HRS) on AKI after orthotropic liver transplantation (OLT).

METHODS

Adult male Sprague-Dawley rats were randomly allocated into four groups: sham, OLT, OLT with HRS (6 ml/kg) pretreatment (HS), OLT with HRS and chloroquine pretreatment (60 mg/kg) group (CQ). All the samples were collected 6 hours after reperfusion. The renal function and oxidative stress level were measured by biochemical and histopathologic examinations. The formation of autophagosome was observed by transmission electron microscopy. The apoptotic rate was determined by terminal deoxynucleotide transferase-mediated deoxyuridine triphosphate nick-end labeling analysis. The expression of caspase-3, cytochrome c, p53, damage-regulated autophagy modulator, Becline-1, microtubule-associated protein light 3-II, p62, lysosome-associated membrane protein-2, and the phosphorylation of p53 were assayed by western blot assay.

RESULTS

Compared with the OLT group, HRS dramatically attenuated the histopathologic damage, restored the renal function, and decreased the oxidative stress level. Simultaneously, HRS significantly ameliorated apoptosis by decreasing the apoptotic rate and inhibiting the expression of caspase-3 and cytochrome c in rats subjected to OLT. The expression of Becline-1 and microtubule-associated protein light 3-II were upregulated with the inhibition of p62 and lysosome-associated membrane protein-2. The inhibition of autophagy by chloroquine counteracted the renoprotective effects of HRS.

CONCLUSIONS

HRS is able to protect against AKI after liver transplantation partly by reducing apoptosis, which is possibly involved in the modulation of p53-mediated autophagy.

Protection against Experimental Stroke by Ganglioside GM1 Is Associated with the Inhibition of Autophagy

Ganglioside GM1, which is particularly abundant in the central nervous system (CNS), is closely associated with the protection against several CNS disorders. However, controversial findings have been reported on the role of GM1 following ischemic stroke. In the present study, using a rat middle cerebral artery occlusion (MCAO) model, we investigated whether GM1 can protect against ischemic brain injury and whether it targets the autophagy pathway. GM1 was delivered to Sprague-Dawley male rats at 3 doses (25 mg/kg, 50 mg/kg, 100 mg/kg) by intraperitoneal injection soon after reperfusion and then once daily for 2 days. The same volume of saline was given as a control. Tat–Beclin-1, a specific autophagy inducer, was administered by intraperitoneal injection at 24 and 48 hours post-MCAO. Infarction volume, mortality and neurological function were assessed at 72 hours after ischemic insult. Immunofluorescence and Western blotting were performed to determine the expression of autophagy-related proteins P62, LC3 and Beclin-1 in the penumbra area. No significant changes in mortality and physiological variables (heart rate, blood glucose levels and arterial blood gases) were observed between the different groups. However, MCAO resulted in enhanced conversion of LC3-I into LC3-II, P62 degradation, high levels of Beclin-1, a large area infarction (26.3±3.6%) and serious neurobehavioral deficits. GM1 (50 mg/kg) treatment significantly reduced the autophagy activation, neurobehavioral dysfunctions, and infarction volume (from 26.3% to 19.5%) without causing significant adverse side effects. However, this biological function could be abolished by Tat–Beclin-1. In conclusion: GM1 demonstrated safe and robust neuroprotective effects that are associated with the inhibition of autophagy following experimental stroke.

Ischemic conditioning-induced endogenous brain protection: Applications pre-, per- or post-stroke

In the area of brain injury and neurodegenerative diseases, a plethora of experimental and clinical evidence strongly indicates the promise of therapeutically exploiting the endogenous adaptive system at various levels like triggers, mediators and the end-effectors to stimulate and mobilize intrinsic protective capacities against brain injuries. It is believed that ischemic pre-conditioning and post-conditioning are actually the strongest known interventions to stimulate the innate neuroprotective mechanism to prevent or reverse neurodegenerative diseases including stroke and traumatic brain injury. Recently, studies showed the effectiveness of ischemic per-conditioning in some organs. Therefore the term ischemic conditioning, including all interventions applied pre-, per- and post-ischemia, which spans therapeutic windows in 3 time periods, has recently been broadly accepted by scientific communities. In addition, it is extensively acknowledged that ischemia-mediated protection not only affects the neurons but also all the components of the neurovascular network (consisting of neurons, glial cells, vascular endothelial cells, pericytes, smooth muscle cells, and venule/veins). The concept of cerebroprotection has been widely used in place of neuroprotection. Intensive studies on the cellular signaling pathways involved in ischemic conditioning have improved the mechanistic understanding of tolerance to cerebral ischemia. This has added impetus to exploration for potential pharmacologic mimetics, which could possibly induce and maximize inherent protective capacities. However, most of these studies were performed in rodents, and the efficacy of these mimetics remains to be evaluated in human patients. Several classical signaling pathways involving apoptosis, inflammation, or oxidation have been elaborated in the past decades. Newly characterized mechanisms are emerging with the advances in biotechnology and conceptual renewal. In this review we are going to focus on those recently reported methodological and mechanistic discoveries in the realm of ischemic conditioning. Due to the varied time differences of ischemic conditioning in different animal models and clinical trials, it is important to define optimal timing to achieve the best conditioning induced neuroprotection. This brings not only an opportunity in the treatment of stroke, but challenges as well, as data is just becoming available and the procedures are not yet optimized. The purpose of this review is to shed light on exploiting these ischemic conditioning modalities to protect the cerebrovascular system against diverse injuries and neurodegenerative disorders.

PUMA is invovled in ischemia/reperfusion-induced apoptosis of mouse cerebral astrocytes

PUMA (p53-upregulated modulator of apoptosis), a BH3-only member of the Bcl-2 protein family, is required for p53-dependent and p53-independent forms of apoptosis. PUMA has been invovled in the onset and progress of several diseases, including cancer, acquired immunodeficiency syndrome, and ischemic brain disease. Although many studies have shown that ischemia and reperfusion (I/R) can induce the apoptosis of astrocytes, the role of PUMA in I/R-mediated apoptosis of cerebral astrocyte apoptosis remains unclear. To mimic in vivo I/R conditions, primary mouse cerebral astrocytes were incubated in a combinational cultural condition of oxygen, glucose, and serum deprivation (OSGD) for 1 h followed by reperfusion (OSGD/R). Cell death determination assays and cell viability assays indicated that OSGD and OSGD/R induce the apoptosis of primary cerebral astrocytes. The expression of PUMA was significantly elevated in primary cerebral astrocytes during OSGD/R. Moreover, targeted down-regulation of PUMA by siRNA transfection significantly decreased the OSGD/R-induced apoptosis of primary cerebral astrocytes. We also found that OSGD and OSGD/R triggered the release of cytochrome c in astrocytes, indicating the dependence on a mitochondrial apoptotic pathway. Reactive oxygen species (ROS) was extremely generated during OSGD and OSGD/R, and the elimination of ROS by treated with N-acetyl-L-cysteine (NAC) remarkably inhibited the expression of PUMA and the apoptosis of primary cerebral astrocytes. The activation of Caspase 3 and Caspase 9 was extremely elevated in primary cerebral astrocytes during OSGD. In addition, we found that knockdown of PUMA led to the depressed expression of Bax, cleaved caspase-9 and caspase-3 during OSGD/R. These results indicate that PUMA is invovled in the apoptosis of cerebral astrocytes upon I/R injury.

Ischemic preconditioning provides neuroprotection by induction of AMP-activated protein kinase-dependent autophagy in a rat model of ischemic stroke

Accumulating evidence suggests that ischemic preconditioning (IPC) increases cerebral tolerance to the subsequent ischemic exposure. However, the underlying mechanisms are still not fully understood. In the present study, we tested the hypothesis that AMP-activated protein kinase (AMPK)-dependent autophagy contributed to the neuroprotection of IPC in rats with permanent cerebral ischemia. Male Sprague-Dawley rats were pretreated with vehicle, compound C (an AMPK inhibitor), or 3-methyladenine (3-MA, an autophagy inhibitor) and then were subjected to IPC induced by a 10-min middle cerebral artery occlusion. Afterward, the brain AMPK activity and autophagy biomarkers were measured. At 24 h after IPC, permanent cerebral ischemia was induced in these rats, and infarct volume, neurological deficits as well as cell apoptosis were evaluated 24 h later. We demonstrated that IPC activated AMPK and induced autophagy in the brain, which was accompanied by a reduction of infract volume, neurological deficits, and cell apoptosis after cerebral ischemia. Meanwhile, the IPC-induced autophagy was inhibited by compound C while the neuroprotection of IPC was abolished by compound C or 3-MA. These findings suggest that AMPK-mediated autophagy contributes to the neuroprotection of IPC, highlighting AMPK as a therapeutic target for stroke prevention and treatment.