Novel Stroke Therapeutics: Unraveling Stroke Pathophysiology and Its Impact on Clinical Treatments

Circular RNA circPRDX3 mediates neuronal survival apoptosis in ischemic stroke by targeting miR-641 and NPR3

OBJECTIVE

circPRDX3 is a circular RNA (circRNA) that has received little attention yet. The purpose of this research is to elucidate circPRDX3 expression pattern and its underlying network in ischemic stroke (IS).

METHODS

Oxygen-glucose deprivation on/reoxygenation (OGD/R) and mice model of middle cerebral artery occlusion (MCAO) were used to generate IS model in N2a cells or mice, respectively. Expression levels of circPRDX3, miR-641, Natriuretic Peptide Receptor 3 (NPR3), and members of the mitogen-activated protein kinases (MAPK) pathway were determined using real-time quantitative PCR (qRT-PCR) and western blot. Cell viability was assessed by CCK-8 assay and apoptosis was evaluated using TUNEL staining and flow cytometry. Molecule-molecule interactions were verified by dual luciferase and RNA immunoprecipitation (RIP) assays. The infarcted area was depicted by Triphenyl tetrazolium chloride (TTC) staining and the level of neurological function was measured using National Institute of Health stroke scale (NIHSS).

RESULTS

CircPRDX3 and NPR3 were shown to be considerably downregulated in IS samples, as well as OGD/R cells or MCAO mice, while miR-641 was found to be significantly upregulated. A circPRDX3/miR-641/NPR3 mechinary was verified using luciferase and RIP assays. Overexpression of circPRDX3 dramatically reduced miR-641 expression and increased NPR3 expression, boosting cell survival and lowering apoptosis in an OGD/R model, either with inactivated MAPK signaling pathways. Moreover, overexpression of circPRDX3 lowered infarct volume and enhanced neurobehavioral outcomes in mice after MCAO, and these protective effects were dramatically abrogated by depletion of NPR3.

CONCLUSION

Altogether, circPRDX3 inhibited the development of IS by sponging miR-641, hence increasing NPR3 expression and inactivating MAPK pathway. These results may aid in the search of potential therapy targets for IS.

Network pharmacology approach to investigate the multitarget mechanisms of Zhishi Rhubarb Soup on acute cerebral infarction

CONTEXT

Zhishi Rhubarb Soup (ZRS) is a traditional Chinese medicine formula used in the clinic to treat acute cerebral infarction (ACI) for many years. However, the exact mechanism of the treatment remains unclear.

OBJECTIVE

This study elucidates the multitarget mechanisms underlying the effects of ZRS on ACI using network pharmacology analysis and verify its effect by performing animal experiments.

MATERIALS AND METHODS

Using the network pharmacology approach, the multiple components, critical targets and potential mechanisms of ZRS against ACI were investigated. Six herbal names of ZRS and 'acute cerebral infarction' were used as keywords to search the relevant databases. In addition, we established the MCAO model to verify the results of network pharmacology enrichment analysis. ZRS (10 g crude drug/kg) was gavaged once per day for 7 consecutive days beginning 3 h after model establishment. After ZRS treatment, TTC staining, Western blot analysis, IHC and ELISA were conducted to further explore the mechanism of ZRS intervention in ACI.

RESULTS

The network pharmacology approach identified 69 key targets, 10 core genes and 169 signalling pathways involved in the treatment of ACI with ZRS. In vivo experiment showed that ZRS treatment significantly reduced cerebral infarction volume (42.76%). It also reduced the expression level of AGE, RAGE and P65; and inhibited the expression of inflammatory MMP-9 and IFN-γ.

CONCLUSIONS

This study demonstrated that ZRS improved cerebral ischaemic injury by inhibiting neuroinflammation partly via the AGE-RAGE signalling pathway. It provides a theoretical basis for the clinical application of ZRS in the treatment of ACI.

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.

Antagonism of histamine H3 receptor promotes angiogenesis following focal cerebral ischemia

Our previous study showed that H3 receptor antagonists reduced neuronal apoptosis and cerebral infarction in the acute stage after cerebral ischemia, but through an action independent of activation of histaminergic neurons. Because enhanced angiogenesis facilitates neurogenesis and neurological recovery after ischemic stroke, we herein investigated whether antagonism of H3R promoted angiogenesis after brain ischemia. Photothrombotic stroke was induced in mice. We showed that administration of H3R antagonist thioperamide (THIO, 10 mg·kg-1·d-1, i.p., from D1 after cerebral ischemia) significantly improved angiogenesis assessed on D14, and attenuated neurological defects on D28 after cerebral ischemia. Compared with wild-type mice, Hrh3-/- mice displayed more blood vessels in the ischemic boundary zone on D14, and THIO administration did not promote angiogenesis in these knockout mice. THIO-promoted angiogenesis in mice was reversed by i.c.v. injection of H3R agonist immepip, but not by H1 and H2 receptor antagonists, histidine decarboxylase inhibitor α-fluoromethylhistidine, or histidine decarboxylase gene knockout (HDC-/-), suggesting that THIO-promoted angiogenesis was independent of activation of histaminergic neurons. In vascular endothelial cells (bEnd.3), THIO (10-9-10-7 M) dose-dependently facilitated cell migration and tube formation after oxygen glucose deprivation (OGD), and H3R knockdown caused similar effects. We further revealed that H3R antagonism reduced the interaction between H3R and Annexin A2, while knockdown of Annexin A2 abrogated THIO-promoted angiogenesis in bEnd.3 cells after OGD. Annexin A2-overexpressing mice displayed more blood vessels in the ischemic boundary zone, which was reversed by i.c.v. injection of immepip. In conclusion, this study demonstrates that H3R antagonism promotes angiogenesis after cerebral ischemia, which is independent of activation of histaminergic neurons, but related to the H3R on vascular endothelial cells and its interaction with Annexin A2. Thus, H3R antagonists might be promising drug candidates to improve angiogenesis and neurological recovery after ischemic stroke.

Bone marrow mesenchymal stem cell-derived exosomes carrying long noncoding RNA ZFAS1 alleviate oxidative stress and inflammation in ischemic stroke by inhibiting microRNA-15a-5p

BACKGROUND/AIM

Bone marrow mesenchymal stem cell (BMSC)-derived exosomes can prevent oxidative stress and inflammation in cerebral ischemia-reperfusion injury. This study intended to assess influences of BMSC-released exosomes on oxidative stress and inflammation following ischemic stroke.

METHODS

In vitro and in vivo models were developed using oxygen-glucose deprivation/reperfusion (OGD/R) and middle cerebral artery occlusion (MCAO), respectively. After exosome isolation, co-culture experiments of BMSCs or BMSC-derived exosomes and OGD/R-treated BV-2 cells were implemented to evaluate the impacts of BMSCs or BMSC-secreted exosomes on proliferation, inflammation, oxidative stress, and apoptosis. The gain-of-function experiments of ZFAS1 or microRNA (miR)-15a-5p were conducted to investigate the associated mechanisms. Besides, MCAO mice were injected with exosomes from BMSCs overexpressing ZFAS1 for in vivo verification. The binding of ZFAS1 to miR-15a-5p was assessed through dual-luciferase reporter gene assay.

RESULTS

Co-culture with BMSCs accelerated proliferation and downregulated IL-1β, IL-6, and TNF-α in OGD/R-exposed BV-2 cells, accompanied by increased SOD level and decreased MDA level and apoptosis, all of which were nullified by inhibiting exosome secretion. Mechanistically, ZFAS1 bound to miR-15a-5p to negatively orchestrate its expression. In addition, BMSC-released exosomes or BMSC-secreted exosomal ZFAS1 augmented proliferation but reduced oxidative stress, apoptosis, and inflammation in OGD/R-exposed BV-2 cells, whereas these impacts of BMSC-released exosomal ZFAS1 were nullified by overexpressing miR-15a-5p. Moreover, BMSC-derived exosomal ZFAS1 diminished MCAO-induced oxidative stress, cerebral infarction, and inflammation in mice.

CONCLUSIONS

Conclusively, BMSC-released exosomes might carry long noncoding RNA ZFAS1 to curb oxidative stress and inflammation related to ischemic stroke, which was possibly realized through miR-15a-5p inhibition.

Primary Prevention of Ischemic Stroke

Ischemic stroke is by far the most common type of cerebrovascular event and remains a major cause of death and disability globally. Despite advancements in acute stroke care, primary prevention is still the most cost-effective approach in reducing the burden of ischemic stroke. The two main strategies for primary stroke prevention include population-wide versus high-risk group interventions. Interventions such as increasing access to primary care, regulation of salt and sugar contents in processed foods, public education, and campaigns to control cerebrovascular risk factors are examples of population-wide interventions. High-risk group interventions, on the other hand, focus on recognition of individuals at risk and aim to modify risk factors in a timely and multifaceted manner. This article provides an overview on conventional modifiable risk factors for ischemic stroke and highlights the emerging risk factors and approaches for high-risk group identification and treatment.

Biological and neurological activities of astaxanthin (Review)

Astaxanthin is a lipid‑soluble carotenoid produced by various microorganisms and marine animals, including bacteria, yeast, fungi, microalgae, shrimps and lobsters. Astaxanthin has antioxidant, anti‑inflammatory and anti‑apoptotic properties. These characteristics suggest that astaxanthin has health benefits and protects against various diseases. Owing to its ability to cross the blood‑brain barrier, astaxanthin has received attention for its protective effects against neurological disorders, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, cerebral ischemia/reperfusion, subarachnoid hemorrhage, traumatic brain injury, spinal cord injury, cognitive impairment and neuropathic pain. Previous studies on the neurological effects of astaxanthin are mostly based on animal models and cellular experiments. Thus, the biological effects of astaxanthin on humans and its underlying mechanisms are still not fully understood. The present review summarizes the neuroprotective effects of astaxanthin, explores its mechanisms of action and draws attention to its potential clinical implications as a therapeutic agent.

Delivery of miRNAs through Metal-Organic Framework Nanoparticles for Assisting Neural Stem Cell Therapy for Ischemic Stroke

Stroke is the most common cause of disability globally. Neural stem cell (NSC) therapy, which can replace lost and damaged neurons, has been proposed as a potential treatment for stroke. The therapeutic efficacy of NSC therapy is hindered by the fact that only a small number of NSCs undergo neuronal differentiation. Neuron-specific miR-124, which promotes the differentiation of NSCs into mature neurons, can be combined with NSC therapy to cure ischemic stroke. However, the instability and poor internalization of miR-124 seriously hamper its broad clinical application. Herein, an innovative strategy involving delivery of miR-124 via a Ca-MOF@miR-124 nanodelivery system, which effectively prevents the degradation of miR-124 by nucleases and promotes the internalization of miR-124 by NSCs, is presented. The effect of accelerated neuronal directed differentiation of NSCs was assessed through in vitro cell experiments, and the clinical application potential of this nanodelivery system for the treatment of ischemic stroke was assessed through in vivo experiments involving the combination of NSC therapy and Ca-MOF@miR-124 nanoparticles. The results indicate that Ca-MOF@miR-124 nanoparticles can promote the differentiation of NSCs into mature neurons with electrophysiological function within 5 days. The differentiation rate of cells treated with Ca-MOF@miR-124 nanoparticles was at least 5 days faster than that of untreated cells. Moreover, Ca-MOF@miR-124 nanoparticles decreased the ischemic area to almost normal levels by day 7. The combination of Ca-MOF@miR-124 nanoparticles and NSC therapy will enhance the treatment of traumatic nerve injury and neurodegenerative diseases.

The interconnections between the microtubules and mitochondrial networks in cardiocerebrovascular diseases: Implications for therapy

Microtubules, a highly dynamic cytoskeleton, participate in many cellular activities including mechanical support, organelles interactions, and intracellular trafficking. Microtubule organization can be regulated by modification of tubulin subunits, microtubule-associated proteins (MAPs) or agents modulating microtubule assembly. Increasing studies demonstrate that microtubule disorganization correlates with various cardiocerebrovascular diseases including heart failure and ischemic stroke. Microtubules also mediate intracellular transport as well as intercellular transfer of mitochondria, a power house in cells which produce ATP for various physiological activities such as cardiac mechanical function. It is known to all that both microtubules and mitochondria participate in the progression of cancer and Parkinson's disease. However, the interconnections between the microtubules and mitochondrial networks in cardiocerebrovascular diseases remain unclear. In this paper, we will focus on the roles of microtubules in cardiocerebrovascular diseases, and discuss the interplay of mitochondria and microtubules in disease development and treatment. Elucidation of these issues might provide significant diagnostic value as well as potential targets for cardiocerebrovascular diseases.

The neurovascular unit and systemic biology in stroke - implications for translation and treatment

Ischaemic stroke is a leading cause of disability and death for which no acute treatments exist beyond recanalization. The development of novel therapies has been repeatedly hindered by translational failures that have changed the way we think about tissue damage after stroke. What was initially a neuron-centric view has been replaced with the concept of the neurovascular unit (NVU), which encompasses neuronal, glial and vascular compartments, and the biphasic nature of neural-glial-vascular signalling. However, it is now clear that the brain is not the private niche it was traditionally thought to be and that the NVU interacts bidirectionally with systemic biology, such as systemic metabolism, the peripheral immune system and the gut microbiota. Furthermore, these interactions are profoundly modified by internal and external factors, such as ageing, temperature and day-night cycles. In this Review, we propose an extension of the concept of the NVU to include its dynamic interactions with systemic biology. We anticipate that this integrated view will lead to the identification of novel mechanisms of stroke pathophysiology, potentially explain previous translational failures, and improve stroke care by identifying new biomarkers of and treatment targets in stroke.

Long-term administration of salvianolic acid A promotes endogenous neurogenesis in ischemic stroke rats through activating Wnt3a/GSK3β/β-catenin signaling pathway

Stroke is the major cause of death and disability worldwide. Most stroke patients who survive in the acute phase of ischemia display various extents of neurological deficits. In order to improve the prognosis of ischemic stroke, promoting endogenous neurogenesis has attracted great attention. Salvianolic acid A (SAA) has shown neuroprotective effects against ischemic diseases. In the present study, we investigated the neurogenesis effects of SAA in ischemic stroke rats, and explored the underlying mechanisms. An autologous thrombus stroke model was established by electrocoagulation. The rats were administered SAA (10 mg/kg, ig) or a positive drug edaravone (5 mg/kg, iv) once a day for 14 days. We showed that SAA administration significantly decreased infarction volume and vascular embolism, and ameliorated pathological injury in the hippocampus and striatum as well as the neurological deficits as compared with the model rats. Furthermore, we found that SAA administration significantly promoted neural stem/progenitor cells (NSPCs) proliferation, migration and differentiation into neurons, enhanced axonal regeneration and diminished neuronal apoptosis around the ipsilateral subventricular zone (SVZ), resulting in restored neural density and reconstructed neural circuits in the ischemic striatum. Moreover, we revealed that SAA-induced neurogenesis was associated to activating Wnt3a/GSK3β/β-catenin signaling pathway and downstream target genes in the hippocampus and striatum. Edaravone exerted equivalent inhibition on neuronal apoptosis in the SVZ, as SAA, but edaravone-induced neurogenesis was weaker than that of SAA. Taken together, our results demonstrate that long-term administration of SAA improves neurological function through enhancing endogenous neurogenesis and inhibiting neuronal apoptosis in ischemic stroke rats via activating Wnt3a/GSK3β/β-catenin signaling pathway. SAA may be a potential therapeutic drug to promote neurogenesis after stroke.

The multifaceted actions of the lncRNA H19 in cardiovascular biology and diseases

Cardiovascular diseases are the leading cause of death and debility worldwide. Various molecular mechanisms have been studied to better understand the development and progression of cardiovascular pathologies with hope to eradicate these diseases. With the advancement of the sequencing technology, it is revealed that the majority of our genome is non-coding. A growing body of literature demonstrates the critical role of long non-coding RNAs (lncRNAs) as epigenetic regulators of gene expression. LncRNAs can regulate cellular biological processes through various distinct molecular mechanisms. The abundance of lncRNAs in the cardiovascular system indicates their significance in cardiovascular physiology and pathology. LncRNA H19, in particular, is a highly evolutionarily conserved lncRNA that is enriched in cardiac and vascular tissue, underlining its importance in maintaining homeostasis of the cardiovascular system. In this review, we discuss the versatile function of H19 in various types of cardiovascular diseases. We highlight the current literature on H19 in the cardiovascular system and demonstrate how dysregulation of H19 induces the development of cardiovascular pathophysiology.

Effect of transcranial direct-current stimulation on executive function and resting EEG after stroke: A pilot randomized controlled study

BACKGROUND

The effects of transcranial direct current stimulation (tDCS) on post-stroke executive impairment (PSEI) remain controversial. Resting stateelectroencephalogram (EEG) can assist in the diagnosis and assessment of executive dysfunction.

OBJECTIVES

We aimed to use EEG to explore the effect of tDCS on executive function among stroke patients.

METHODS

Twenty-four patients with PSEI were randomly divided into experimental and control groups, which received real and sham stimulation, respectively. Anodal electrical stimulation was applied to the left dorsolateral prefrontal lobe (F3). The stimulation intensity was 2 mA for 20 min once daily for 7 days. Executive function was monitored using neuropsychological scales.

RESULTS

The experimental group outperformed the control group in clinical scale results, with significant differences in the following scores: symbol digital modalities test, TMT-A, TMT-B, and digital span test. In the left central zone, theta band power was significantly higher after anodal electrical stimulation than before. Analysis of the correlation between EEG power and psychometric scores revealed that the power change was positively correlated with the scores on the symbol digital modality test (r = 0.435, p < 0.05).

CONCLUSION

Anodal tDCS can enhance executive function in patients with PSEI, and tDCS-related improvements are related to the enhancement of theta power in the affected region.

A Review of Neuroprotective Effects and Mechanisms of Ginsenosides From Panax Ginseng in Treating Ischemic Stroke

Ischemic stroke has been considered one of the leading causes of mortality and disability worldwide, associated with a series of complex pathophysiological processes. However, effective therapeutic methods for ischemic stroke are still limited. Panax ginseng, a valuable traditional Chinese medicine, has been long used in eastern countries for various diseases. Ginsenosides, the main active ingredient of Panax ginseng, has demonstrated neuroprotective effects on ischemic stroke injury during the last decade. In this article, we summarized the pathophysiology of ischemic stroke and reviewed the literature on ginsenosides studies in preclinical and clinical ischemic stroke. Available findings showed that both major ginsenosides and minor ginsenosides (such as Rg3, Rg5, and Rh2) has a potential neuroprotective effect, mainly through attenuating the excitotoxicity, Ca²⁺ overload, mitochondria dysfunction, blood-brain barrier (BBB) permeability, anti-inflammation, anti-oxidative, anti-apoptosis, anti-pyroptosis, anti-autophagy, improving angiogenesis, and neurogenesis. Therefore, this review brings a current understanding of the mechanisms of ginsenosides in the treatment of ischemic stroke. Further studies, especially in clinical trials, will be important to confirm the clinical value of ginseng and ginsenosides.

Signaling pathways involved in ischemic stroke: molecular mechanisms and therapeutic interventions

Ischemic stroke is caused primarily by an interruption in cerebral blood flow, which induces severe neural injuries, and is one of the leading causes of death and disability worldwide. Thus, it is of great necessity to further detailly elucidate the mechanisms of ischemic stroke and find out new therapies against the disease. In recent years, efforts have been made to understand the pathophysiology of ischemic stroke, including cellular excitotoxicity, oxidative stress, cell death processes, and neuroinflammation. In the meantime, a plethora of signaling pathways, either detrimental or neuroprotective, are also highly involved in the forementioned pathophysiology. These pathways are closely intertwined and form a complex signaling network. Also, these signaling pathways reveal therapeutic potential, as targeting these signaling pathways could possibly serve as therapeutic approaches against ischemic stroke. In this review, we describe the signaling pathways involved in ischemic stroke and categorize them based on the pathophysiological processes they participate in. Therapeutic approaches targeting these signaling pathways, which are associated with the pathophysiology mentioned above, are also discussed. Meanwhile, clinical trials regarding ischemic stroke, which potentially target the pathophysiology and the signaling pathways involved, are summarized in details. Conclusively, this review elucidated potential molecular mechanisms and related signaling pathways underlying ischemic stroke, and summarize the therapeutic approaches targeted various pathophysiology, with particular reference to clinical trials and future prospects for treating ischemic stroke.

Transplantation of Roxadustat-preconditioned bone marrow stromal cells improves neurological function recovery through enhancing grafted cell survival in ischemic stroke rats

AIMS

The therapeutic effect of bone marrow stromal cell (BMSC) transplantation for ischemic stroke is limited by its low survival rate. The purpose of this study was to evaluate whether Roxadustat (FG-4592) pretreatment could promote the survival rate of grafted BMSCs and improve neurological function deficits in ischemia rats.

METHODS

Oxygen-glucose deprivation (OGD) and permanent middle cerebral artery occlusion (pMCAO) were constructed as stroke models in vitro and in vivo. Flow cytometry analysis and expression of Bax and Bcl-2 were detected to evaluate BMSCs apoptosis. Infarct volume and neurobehavioral score were applied to evaluate functional recovery. Inflammatory cytokine expression, neuronal apoptosis, and microglial M1 polarization were assessed to confirm the enhanced neurological recovery after FG-4592 pretreatment.

RESULTS

FG-4592 promoted autophagy level to inhibit OGD-induced apoptosis through HIF-1α/BNIP3 pathway. GFP and Ki67 double staining showed an improved survival rate of BMSCs in the FG-4592 group, whereas infarct volume and neurobehavioral score verified its enhanced neurological recovery activity simultaneously. NeuN and Iba-1 fluorescence staining showed improved neural survival and decreased microglial activation, along with decreased IL-1β, IL-6, and TNF-α levels through the TLR-4/NF-kB pathway.

CONCLUSIONS

FG-4592 pretreated BMSCs improve neurological function recovery after stroke and are likely to be a promising strategy for stroke management.

Role of autophagy and transcriptome regulation in acute brain injury

Autophagy is an evolutionarily conserved intracellular system that routes distinct cytoplasmic cargo to lysosomes for degradation and recycling. Accumulating evidence highlight the mechanisms of autophagy, such as clearance of proteins, carbohydrates, lipids and damaged organelles. The critical role of autophagy in selective degradation of the transcriptome is still emerging and could shape the total proteome of the cell, and thus can regulate the homeostasis under stressful conditions. Unregulated autophagy that potentiates secondary brain damage is a key pathological features of acute CNS injuries such as stroke and traumatic brain injury. This review discussed the mutual modulation of autophagy and RNA and its significance in mediating the functional consequences of acute CNS injuries.

Whole-transcriptome RNA sequencing revealed the roles of chitin-related genes in the eyestalk abnormality of a novel mud crab hybrid (Scylla serrata ♀ × S. paramamosain ♂)

Chitin is a kind of insoluble structural polysaccharide and plays different roles in different species. In crustaceans, it forms the structural components in the exoskeleton. In our previous studies, novel mud crab hybrids have been produced from the interspecific hybridization of Scylla serrata ♀ × S. paramamosain ♂. Some of the hybrid crabs have been found to be morphologically (eyestalk) abnormal, but the genetic mechanism remains unknown. To address this question, we performed whole-transcriptome RNA sequencing on the control group (normal hybrids), abnormal hybrids, and S. paramamosain to uncover the genetic basis underlying this morphological abnormality. A total of 695 mRNAs, 10 miRNAs, 44 circRNAs, and 1957 lncRNAs were differentially expressed between normal and abnormal hybrids. Several differentially expressed genes (DEGs) associated with chitin and cuticle metabolism were identified, including chitin synthase, chitinase, chitin deacetylase, β-N-acetylglucosaminidase, β-1,4-endoglucanase, N-alpha-acetyltransferase, cuticle proprotein, early cuticle protein, and arthrodial cuticle protein. Functional analysis showed that DE miRNAs, DE circRNAs, DE lncRNAs, and lncRNA/circRNA-miRNA-mRNA network were enriched in pathways related to the amino acid, carbohydrate, and glycogen metabolism. Considering the importance of the chitin and cuticle in exoskeleton formation, it can be concluded that the changes in the chitin and cuticle biosynthesis might have caused the eyestalk abnormality in hybrid crabs. These findings can lay the solid foundation for a better understanding of the important roles of chitin and cuticle related genes and the development of hybridization techniques in crustaceans.

Ischemic Brain Stroke and Mesenchymal Stem Cells: An Overview of Molecular Mechanisms and Therapeutic Potential

Ischemic brain injury is associated with a high rate of mortality and disability with no effective therapeutic strategy. Recently, a growing number of studies are focusing on mesenchymal stem cell-based therapies for neurodegenerative disorders. However, despite having the promising outcome of preclinical studies, the clinical application of stem cell therapy remained elusive due to little or no progress in clinical trials. The objective of this study was to provide a generalized critique for the role of mesenchymal stem cell therapy in ischemic stroke injury, its underlying mechanisms, and constraints on its preclinical and clinical applications. Thus, we attempted to present an overview of previously published reports to evaluate the progress and provide molecular basis of mesenchymal stem cells (MSCs) therapy and its application in preclinical and clinical settings, which could aid in designing an effective regenerative therapeutic strategy in the future.

An evaluation of the structure and process of stroke rehabilitation in primary, secondary and tertiary hospitals in Ghana

Background

Evidence shows that quality indicators such as the structure and process of stroke rehabilitation can influence patient outcomes. However, not much attention has been paid to the study of these issues in low- and middle-income countries such as Ghana.

Objectives

Our study evaluated the structure and process of stroke rehabilitation in primary, secondary and tertiary hospitals in the Greater Accra Region of Ghana.

Method

A cross-sectional survey was conducted involving 111 healthcare professionals. The World Health Organization (WHO) situational analysis and Measure of Processes of Care for Service Providers for Adults (MPOC-SP[A]) questionnaires were administered to gather information on the structure and process of stroke rehabilitation. Descriptive statistics were used to summarise data, and chi-square and Kruskal–Wallis tests were used to establish associations and comparisons, respectively.

Results

A stroke unit was only available in the tertiary hospital. Although all three hospitals had a multidisciplinary team approach to care, the constituents differed. Length of hospital-stay, duration of treatment and basis for discharge from acute care were not associated with the hospitals. Therapy sessions, access to computed tomography (CT) and magnetic resonance imaging (MRI) scanning were dependent on the hospitals.

Conclusion

The structure and process of stroke rehabilitation across the three hospitals were similar in some constructs and different in others.

Clinical implications

Data gathered will help to provide information on the available structure and processes of stroke rehabilitation, which could help assess the quality of care provided.

Maternal Inflammation Exaggerates Offspring Susceptibility to Cerebral Ischemia–Reperfusion Injury via the COX-2/PGD2/DP2 Pathway Activation

The pathogenesis of cerebral ischemia–reperfusion (I/R) injury is complex and does not exhibit an effective strategy. Maternal inflammation represents one of the most important factors involved in the etiology of brain injury in newborns. We aimed to investigate the effect of maternal inflammation on offspring susceptibility to cerebral I/R injury and the mechanisms by which it exerts its effects. Pregnant SD rats were intraperitoneally injected with LPS (300 μg/kg/day) at gestational days 11, 14, and 18. Pups were subjected to MCAO/R on postnatal day 60. Primary neurons were obtained from postnatal day 0 SD rats and subjected to OGD/R. Neurological deficits, brain injury, neuronal viability, neuronal damage, and neuronal apoptosis were assessed. Oxidative stress and inflammation were evaluated, and the expression levels of COX-2/PGD2/DP pathway-related proteins and apoptotic proteins were detected. Maternal LPS exposure significantly increased the levels of oxidative stress and inflammation, significantly activated the COX-2/PGD2/DP₂ pathway, and increased proapoptotic protein expression. However, maternal LPS exposure significantly decreased the antiapoptotic protein expression, which subsequently increased neurological deficits and cerebral I/R injury in offspring rats. The corresponding results were observed in primary neurons. Moreover, these effects of maternal LPS exposure were reversed by a COX-2 inhibitor and DP₁ agonist but exacerbated by a DP₂ agonist. In conclusion, maternal inflammatory exposure may increase offspring susceptibility to cerebral I/R injury. Moreover, the underlying mechanism might be related to the activation of the COX-2/PGD2/DP₂ pathway. These findings provide a theoretical foundation for the development of therapeutic drugs for cerebral I/R injury.

Accidente cerebrovascular isquémico de la arteria cerebral media

La segunda causa de muerte a nivel mundial corresponde a los ataques cerebrovasculares (ACV), de los cuales más de dos terceras partes son de origen isquémico. Causan discapacidad a largo plazo por lo que conocer la anatomía de la circulación cerebral y las posibles manifestaciones clínicas del ACV isquémico permite sospechar, diagnosticar y brindar un manejo oportuno y apropiado, reduciendo el impacto en la salud y la calidad de vida del paciente y sus cuidadores. Objetivo: relacionar los últimos hallazgos en la anatomía arterial cerebral, los mecanismos fisiopatológicos y las manifestaciones clínicas del ACV isquémico de la arteria cerebral media (ACM). Materiales y métodos: revisión de la literatura mediante la búsqueda con términos MeSH en la base de datos Medline, incluyendo estudios, ensayos y metaanálisis publicados entre 2000 y 2020 en inglés y español, además de otras referencias para complementar la información. Resultados: se seleccionaron 59 publicaciones, priorizando la de los últimos 5 años y las más relevantes del rango temporal consultado. Conclusiones: son escasos los estudios sobre la presentación clínica de los ACV, lo que sumado a la variabilidad interindividual de la irrigación cerebral, dificulta la determinación clínica de la localización de la lesión dentro del lecho vascular. La reperfusión del área de penumbra isquémica como objetivo terapéutico se justifica por los mecanismos fisiopatológicos de la enfermedad.

Neuroprotective Effect of 1,3-dipalmitoyl-2-oleoylglycerol Derived from Rice Bran Oil against Cerebral Ischemia-Reperfusion Injury in Rats

1,3-Dipalmitoyl-2-oleoylglycerol (POP) is a triacylglyceride found in oils from various natural sources, including palm kernels, sunflower seeds, and rice bran. In the current study, the neuroprotective effects and the specific mechanism of POP derived from rice bran oil were investigated for the first time using the middle cerebral artery occlusion/reperfusion (MCAO/R) model in rats. Orally administered POP at 1, 3, or 5 mg/kg (three times: 0.5 h before MCAO, after 1 h of MCAO, and after 1 h of reperfusion) markedly reduced the MCAO/R-induced infarct/edema volume and neurobehavioral deficits. Glutathione depletion and the oxidative degradation of lipids in the rat brain induced by MCAO/R were prevented by POP administration. The upregulation of phosphorylated p38 MAPKs, inflammatory factors (inducible nitric oxide synthase (i-NOS) and cyclooxygenase-2 (COX-2)), and pro-apoptotic proteins (B-cell lymphoma-2 (Bcl-2) associated X protein (Bax) and cleaved caspase-3) and the downregulation of the anti-apoptotic protein (Bcl-2) in the ischemic brain were significantly inhibited by POP administration. In addition, downregulation of phosphatidylinositol 3′-kinase (PI3K), phosphorylated protein kinase B (Akt), and phosphorylated cyclic (adenosine monophosphate) AMP responsive element-binding protein (CREB) expression in the ischemic brain was inhibited by POP administration. These results suggest that POP might exert neuroprotective effects by inhibition of p38 MAPK and activation of PI3K/Akt/CREB pathway, which is associated with anti-oxidant, anti-apoptotic, and anti-inflammatory action. From the above results, the present study provides evidence that POP might be effectively applied for the management of cerebral ischemia-related diseases.

Therapeutic Potential of Highly Selective A3 Adenosine Receptor Ligands in the Central and Peripheral Nervous System

Ligands of the G_i protein-coupled adenosine A₃ receptor (A₃R) are receiving increasing interest as attractive therapeutic tools for the treatment of a number of pathological conditions of the central and peripheral nervous systems (CNS and PNS, respectively). Their safe pharmacological profiles emerging from clinical trials on different pathologies (e.g., rheumatoid arthritis, psoriasis and fatty liver diseases) confer a realistic translational potential to these compounds, thus encouraging the investigation of highly selective agonists and antagonists of A₃R. The present review summarizes information on the effect of latest-generation A₃R ligands, not yet available in commerce, obtained by using different in vitro and in vivo models of various PNS- or CNS-related disorders. This review places particular focus on brain ischemia insults and colitis, where the prototypical A₃R agonist, Cl-IB-MECA, and antagonist, MRS1523, have been used in research studies as reference compounds to explore the effects of latest-generation ligands on this receptor. The advantages and weaknesses of these compounds in terms of therapeutic potential are discussed.

Analysis of expression profiles and bioinformatics suggests that plasma exosomal circular RNAs may be involved in ischemic stroke in the Chinese Han population

Circular RNAs (circRNAs) have been confirmed to be associated with ischemic stroke(IS), but the involvement of exosomal circRNAs in plasma still needs to be extensively discussed. Therefore, we aimed to investigate the expression profile of exosomal circRNAs in plasma and the potential roles and mechanisms of exosomal circRNAs in the pathogenesis of ischemic stroke in the Chinese Han population. In this study, the plasma exosomal circRNA expression profiles of three IS patients and three healthy controls were analyzed using circRNA sequencing. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis and circRNA-miRNA-mRNA regulatory network analysis were performed for the aberrantly expressed genes. Protein-protein interaction (PPI) networks and molecular complex detection algorithms (MCODEs) were analyzed by STRING and Cystoscope for functional annotation and construction, respectively. RNA-Seq analysis revealed that a total of 3540 circRNAs were aberrantly expressed in exosomes, 1177 circRNAs were significantly upregulated, and 2363 circRNAs were downregulated in IS patients compared to healthy controls. Bioinformatics analysis revealed that the parental genes of differentially expressed circRNAs as well as the mRNAs predicted in the circRNA-miRNA-mRNA regulatory network are enriched for signaling pathways associated with IS pathology, such as the MAPK signaling pathway, lipid and atherosclerosis, neurotrophic factor signaling pathways, mTOR signaling pathway, the p53 signaling pathway etc. Then, 10 hub genes were identified from the PPI and module networks, including FBXW11, FBXW7, UBE2V2, ANAPC7, CDC27, UBC, CDC5L, POLR2H, POLR2F and RBX1. Overall, the present study provides evidence of an altered plasma exosomal circRNA expression profile and its potential function in IS. Our findings may contribute to the study of the pathogenesis of circRNAs in IS and provide ideas for studying potential diagnostic biomarkers and therapeutic targets for IS.

Schizophrenia predisposition gene Unc-51-like kinase 4 for the improvement of cerebral ischemia/reperfusion injury

BACKGROUND

Cerebral ischemia/reperfusion injury (CIRI) has complex pathogenesis, and inhibiting apoptosis and supporting neural progenitor proliferation are extremely beneficial strategies for treating CIRI. Unc-51-like kinase 4 (ULK4), a susceptibility gene for schizophrenia, promotes neural progenitors proliferation. The phosphatidylinositol 3-kinase (PI3K) pathway plays a critical role in CIRI via inhibition of apoptosis. Therefore, the relationship among ULK4, the PI3K pathway, and apoptosis in the context of CIRI has attracted our great interest.

METHODS AND RESULTS

Primary cortical neurons were subjected to oxygen-glucose deprivation/reperfusion (OGD/R), and rats were subjected to middle cerebral artery occlusion/reperfusion (MCAO/R). Transfection of the ULK4-overexpression lentivirus was performed alone or in combination with PI3K inhibitor treatment. Here, we revealed that ULK4 was poorly expressed in the cortex in MCAO/R rats and OGD/R-treated primary cortical neurons, ULK4 overexpression inhibited apoptosis, and reduced neurological deficit scores, cerebral infarct volume, and histopathological damage. Moreover, ULK4 overexpression increased PI3K expression and the p-protein kinase B/AKT and p-glycogen synthase kinase 3 beta (GSK3β)/GSK3β ratios, and inhibited apoptosis, while a PI3K inhibitor reversed the effects of ULK4 overexpression on CIRI.

CONCLUSIONS

ULK4 protects against CIRI, and the underlying mechanism involves PI3K pathway activation which in turn inhibits apoptosis.

COX-2/PGE2 Pathway Inhibits the Ferroptosis Induced by Cerebral Ischemia Reperfusion

Cerebral ischemia reperfusion (I/R) injury easily develops in ischemic stroke, resulting in more serious injury. Ferroptosis is involved in cerebral I/R injury, but the mechanism remains unclear. Prostaglandin E2 (PGE2) is potential to regulate ferroptosis. This study mainly explored the regulation effects of PGE2 on ferroptosis induced by cerebral I/R. We first detected PGE2 levels and ferroptosis status in 11 human brain tissues. Then, we induced a cerebral I/R animal model to examine ferroptosis status in cerebral I/R. We further injected a ferroptosis inhibitor to define the response of the PGE2 pathway to ferroptosis. Finally, we injected PGE2 and pranoprofen to explore the regulation of the cyclooxygenases 2 (COX-2)/PGE2 pathway on ferroptosis in cerebral I/R. We found that PGE2 release was correlated with the levels of reactive oxygen species, malondialdehyde, glutathione peroxidase 4, COX-2, and Spermidine/spermine N1-acetyltransferase 1. Ferroptosis can be induced by cerebral I/R, while inhibition of ferroptosis induced by cerebral I/R can inactivate PGE2 synthases, degrade enzyme, and parts of PGE2 receptors, and reduce cerebral infarct volume. In turn, PGE2 inhibited ferroptosis through the reduction of Fe²⁺, glutathione oxidation, and lipid peroxidation, while pranoprofen, one of the COX inhibitors, played an opposite role. In conclusion, PGE2 was positively correlated with ferroptosis, inhibition of ferroptosis induced by cerebral I/R can inactivate COX-2/PGE2 pathway, and PGE2 inhibited ferroptosis induced by cerebral I/R, possibly via PGE2 receptor 3 and PGE2 receptor 4. Graphical abstract Inhibition of ferroptosis inactivates the COX-2/PGE2 pathway. Cerebral ischemia reperfusion injury induces the secretion of PGE2. After the inhibition of ferroptosis by Fer-1, the expression of cyclooxygenases (COX-1 and COX-2) decreased, and PGE2 synthases cPGES, mPGES-1, and mPGES-2 were also reduced. At the same time, the PGE2 degradation enzyme 15-PGDH was also reduced. Changes in these enzymes ultimately result in the declination of PGE2. Besides, the expression of PGE2 receptors EP3 and EP4 is also inhibited, indicating that the function they mediate is also impaired. In conclusion, after cerebral ischemia reperfusion injury, the inhibition of ferroptosis inactivates the COX-2/PGE2 pathway.

Dodging blood brain barrier with "nano" warriors: Novel strategy against ischemic stroke

Ischemic stroke (IS) is one of the leading causes of death and disability resulting in inevitable burden globally. Ischemic injury initiates cascade of pathological events comprising energy dwindling, failure of ionic gradients, failure of blood brain barrier (BBB), vasogenic edema, calcium over accumulation, excitotoxicity, increased oxidative stress, mitochondrial dysfunction, inflammation and eventually cell death. In spite of such complexity of the disease, the only treatment approved by US Food and Drug Administration (FDA) is tissue plasminogen activator (t-PA). This therapy overcome blood deficiency in the brain along with side effects of reperfusion which are responsible for considerable tissue injury. Therefore, there is urgent need of novel therapeutic perspectives that can protect the integrity of BBB and salvageable brain tissue. Advancement in nanomedicine is empowering new approaches that are potent to improve the understanding and treatment of the IS. Herein, we focus nanomaterial mediated drug delivery systems (DDSs) and their role to bypass and cross BBB especially via intranasal drug delivery. The various nanocarriers used in DDSs are also discussed. In a nut shell, the objective is to provide an overview of use of nanomedicine in the diagnosis and treatment of IS to facilitate the research from benchtop to bedside.

Biological Functions and Regulatory Mechanisms of Hypoxia-Inducible Factor-1α in Ischemic Stroke

Ischemic stroke is caused by insufficient cerebrovascular blood and oxygen supply. It is a major contributor to death or disability worldwide and has become a heavy societal and clinical burden. To date, effective treatments for ischemic stroke are limited, and innovative therapeutic methods are urgently needed. Hypoxia inducible factor-1α (HIF-1α) is a sensitive regulator of oxygen homeostasis, and its expression is rapidly induced after hypoxia/ischemia. It plays an extensive role in the pathophysiology of stroke, including neuronal survival, neuroinflammation, angiogenesis, glucose metabolism, and blood brain barrier regulation. In addition, the spatiotemporal expression profile of HIF-1α in the brain shifts with the progression of ischemic stroke; this has led to contradictory findings regarding its function in previous studies. Therefore, unveiling the Janus face of HIF-1α and its target genes in different type of cells and exploring the role of HIF-1α in inflammatory responses after ischemia is of great importance for revealing the pathogenesis and identifying new therapeutic targets for ischemic stroke. Herein, we provide a succinct overview of the current approaches targeting HIF-1α and summarize novel findings concerning HIF-1α regulation in different types of cells within neurovascular units, including neurons, endothelial cells, astrocytes, and microglia, during the different stages of ischemic stroke. The current representative translational approaches focused on neuroprotection by targeting HIF-1α are also discussed.

Insulin-Like Growth Factor-1 Differentially Modulates Glutamate-Induced Toxicity and Stress in Cells of the Neurogliovascular Unit

The age-related reduction in circulating levels of insulin-like growth factor-1 (IGF-1) is associated with increased risk of stroke and neurodegenerative diseases in advanced age. Numerous reports highlight behavioral and physiological deficits in blood-brain barrier function and neurovascular communication when IGF-1 levels are low. Administration of exogenous IGF-1 reduces the extent of tissue damage and sensorimotor deficits in animal models of ischemic stroke, highlighting the critical role of IGF-1 as a regulator of neurovascular health. The beneficial effects of IGF-1 in the nervous system are often attributed to direct actions on neurons; however, glial cells and the cerebrovasculature are also modulated by IGF-1, and systemic reductions in circulating IGF-1 likely influence the viability and function of the entire neuro-glio-vascular unit. We recently observed that reduced IGF-1 led to impaired glutamate handling in astrocytes. Considering glutamate excitotoxicity is one of the main drivers of neurodegeneration following ischemic stroke, the age-related loss of IGF-1 may also compromise neural function indirectly by altering the function of supporting glia and vasculature. In this study, we assess and compare the effects of IGF-1 signaling on glutamate-induced toxicity and reactive oxygen species (ROS)-produced oxidative stress in primary neuron, astrocyte, and brain microvascular endothelial cell cultures. Our findings verify that neurons are highly susceptible to excitotoxicity, in comparison to astrocytes or endothelial cells, and that a prolonged reduction in IGFR activation increases the extent of toxicity. Moreover, prolonged IGFR inhibition increased the susceptibility of astrocytes to glutamate-induced toxicity and lessened their ability to protect neurons from excitotoxicity. Thus, IGF-1 promotes neuronal survival by acting directly on neurons and indirectly on astrocytes. Despite increased resistance to excitotoxic death, both astrocytes and cerebrovascular endothelial cells exhibit acute increases in glutamate-induced ROS production and mitochondrial dysfunction when IGFR is inhibited at the time of glutamate stimulation. Together these data highlight that each cell type within the neuro-glio-vascular unit differentially responds to stress when IGF-1 signaling was impaired. Therefore, the reductions in circulating IGF-1 observed in advanced age are likely detrimental to the health and function of the entire neuro-glio-vascular unit.

Long non-coding RNA SNHG7 upregulates FGF9 to alleviate oxygen and glucose deprivation-induced neuron cell injury in a miR-134-5p-dependent manner

Long non-coding RNA small nucleolar RNA host gene 7 (SNHG7) was reported to regulate the pathogenesis of ischemic stroke. The study aimed to disclose SNHG7 role in oxygen and glucose deprivation (OGD)-induced Neuro-2a (N2a) cell disorders. An OGD injury cell model was established using N2a cells. The expression of SNHG7, microRNA-134-5p (miR-134-5p) and fibroblast growth factor 9 (FGF9) was determined by quantitative real-time polymerase chain reaction. Protein expression was detected by western blot. Cell viability and Lactate Dehydrogenase (LDH) leakage were determined by cell counting kit-8 and LDH activity detection assays. Oxidative stress was investigated by Superoxide Dismutase and Catalase activity assays as well as Malondialdehyde and Reactive Oxygen Species detection kits. Cell apoptosis and caspase-3 activity were severally demonstrated by flow cytometry and caspase-3 activity assays. The interaction between miR-134-5p and SNHG7 or FGF9 was predicted by online databases, and identified by mechanism assays. OGD treatment decreased SNHG7 and FGF9 expression, but increased miR-134-5p expression. OGD treatment repressed cell viability, promoted LDH leakage and induced oxidative stress and apoptosis in N2a cells, which was rescued by SNHG7 overexpression. SNHG7 acted as a sponge for miR-134-5p, and regulated OGD-triggered cell damage by associating with miR-134-5p. Additionally, miR-134-5p depletion protected N2a cells from OGD-induced injury by targeting FGF9. Ectopic SNHG7 expression protected against OGD-induced neuronal cell injury by inducing FGF9 through sponging miR-134-5p, providing a novel therapeutic target for ischemic stroke.

Dl-3-N-Butylphthalide Attenuates Hypoxic Injury of Neural Stem Cells by Increasing Hypoxia-Inducible Factor-1alpha

OBJECTIVE

To assess the potential effect of dl-3-N-butylphthalide (dl-NBP) for the proliferation and differentiation of neural stem cells (NSCs) against hypoxia and the underlying mechanism.

MATERIALS AND METHODS

Hippocampal NSCs were obtained from fetal rats. NSCs combined with dl-NBP and single NSCs were cultured. The impact of siRNA-mediated hypoxia-inducible factor-1alpha (HIF-1α) knockdown on NSCs was detected with western blotting (WB) and quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR). Cell-counting kit-8 assay was used for evaluating the viability of NSCs. Levels of HIF-1α protein were measured using WB, and vascular endothelial growth factor (VEGF) expression was quantified using RT-qPCR and enzyme-linked immunosorbent assay.

RESULTS

Compared with 7 different concentrations of dl-NBP, 0.25 g/L was determined as the optimal concentration to significantly increase the viability of NSCs (p < 0.001). Dl-NBP can significantly increase the viability of hypoxic NSCs (p < 0.001) and improve the differentiation of hypoxic NSCs into astrocytes (p = 0.001) and oligodendrocytes (p < 0.001). Meanwhile, Dl-NBP can significantly elevate levels of HIF-1α protein (p < 0.001) and VEGF mRNA (p = 0.001) / protein (p < 0.001) in NSCs in the hypoxic environment. However, after transfection with HIF-1α siRNA in NSCs, the viability and differentiation of NSCs was not recovered using dl-NBP under the hypoxic condition, as well as levels of HIF-1α and VEGF.

CONCLUSION

Dl-NBP can reverse the weaker proliferation and differentiation power of NSCs in the hypoxic environment. The HIF-1α - VEGF pathway may be implicated in this protective effect of dl-NBP.

CircDLGAP4 overexpression relieves oxygen-glucose deprivation-induced neuronal injury by elevating NEGR1 through sponging miR-503-3p

Circular RNAs (circRNAs) have been reported to play vital regulatory roles in human diseases. However, the functions of circRNAs in ischemic stroke (IS) are limited. In this study, we aimed to explore the functions and mechanisms of circRNA DLG associated protein 4 (circDLGAP4) in IS development. Oxygen-glucose deprivation (OGD)-treated HCN-2 cells were used to mimic IS environment in vitro. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was used to detect the levels of circDLGAP4, microRNA-503-3p (miR-503-3p) and neuronal growth regulator 1 (NEGR1) mRNA. RNase R assay was conducted to analyze the stability of circDLGAP4. Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis were adopted for cell viability and death, respectively. Western blot assay was performed for protein levels. Enzyme-linked immunosorbent assay (ELISA) kits were used to examine the concentrations of inflammatory cytokines. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay and RNA pull-down assay were employed to analyze the relationships among circDLGAP4, miR-503-3p and NEGR1. CircDLGAP4 level was declined in HCN-2 cells after OGD treatment. CircDLGAP4 overexpression promoted cell viability and suppressed cell death and inflammatory cytokine concentrations in OGD-treated HCN-2 cells. CircDLGAP4 acted as the sponge for miR-503-3p and the impacts of circDLGAP4 overexpression on cell viability, death and inflammation in OGD-treated HCN-2 cells were reversed by miR-503-3p elevation. Furthermore, NEGR1 was the target gene of miR-503-3p. MiR-503-3p inhibition ameliorated OGD-induced HCN-2 cell impairments, but NEGR1 knockdown abolished the effects. CircDLGAP4 alleviated OGD-induced HCN-2 cell damage by regulating miR-503-3p/NEGR1 axis.

CD300a blockade enhances efferocytosis by infiltrating myeloid cells and ameliorates neuronal deficit after ischemic stroke

[Figure: see text].

Neuroprotective Effects of Deproteinized Calf Serum in Ischemic Stroke

Deproteinized calf serum (DCS) may have neuroprotective effects after ischemic stroke. The aim of this study is to investigate whether and how the DCS inhibits neuronal injury following cerebral ischemia. Rats were subjected to 2 h transient middle cerebral artery occlusion (MCAO). One dose of 0.125 mg/gbw DCS was given immediately after reperfusion. Neurological deficit and infarct volume at 24 h post-MCAO in DCS-treated rats were lower than those in vehicle-treated rats (p < 0.0005). In cultured neurons model, cell viability was decreased, and apoptosis was increased by oxygen-glucose deprivation/reperfusion (OGD/R) (p < 0.0005). These effects of OGD/R were attenuated by 0.4 μg/μl DCS (p < 0.05) that were validated by CCK8 cell viability assay, phycoerythrin–Annexin V Apoptosis Detection assay, and TUNEL assay. Furthermore, the increase of intracellular ROS level in cultured neurons was suppressed by DCS (p < 0.05). Compared with cells subjected to OGD/R, the expression level of Bax protein decreased, and bcl-2 protein increased after DSC treatment (p < 0.05). Overall, the neuroprotective effects of DCS following cerebral ischemia may in part be due to decreased ROS production and inhibition of apoptosis.

Dengzhanxixin Injection Ameliorates Cognitive Impairment Through a Neuroprotective Mechanism Based on Mitochondrial Preservation in Patients With Acute Ischemic Stroke

Acute ischemic stroke (AIS) is a global health burden and cognitive impairment is one of its most serious complication. Adequate interventions for AIS may have the potential to improve cognitive outcomes. In the present study, we selected Erigeron breviscapus (Vaniot) Hand.-Mazz. injection (Dengzhanxixin injection, DZXI), a widely used Chinese herbal injection, in contrast to edaravone as the positive control drug to test its potential to ameliorates neurological and cognitive impairments caused by AIS. We performed a 2-week randomized trial with these two drugs in AIS patients presenting mild to moderate cognitive impairments. Neuropsychological tests and MRI examinations showed that DZXI attenuated the neurological and cognitive impairments of patients and protected the grey matter in specific regions from ischemic damage. Notably, DZXI exerted better effects than edaravone in some neuropsychological tests, probably due to the protective effect of DZXI on grey matter. To explore the therapeutic mechanisms, we carried out an experiment with a middle cerebral artery occlusion rat model. We found that DZXI decreased the infarct volume and increased the survival of neuronal cells in the ischemic penumbra; furthermore, DZXI modulated the mitochondrial respiratory chain process and preserved the mitochondrial structure in the brain tissue. Overall, our data suggested that the administration of DZXI is effective at ameliorating neurological and cognitive impairments in AIS, and the underlying mechanisms are related to the protective effects of DZXI on cerebral neurons and neuronal mitochondria.

Buyang Huanwu Decoction promotes neurogenesis via sirtuin 1/autophagy pathway in a cerebral ischemia model

Stroke is one of the main causes of disease-related mortality worldwide. Buyang Huanwu Decoction (BHD) has been used to protect against stroke and stroke-induced disability for several years in China. Studies have shown that BHD can relieve neuronal damage in rats with cerebral ischemia/reperfusion (I/R) injury. However, the mechanism remains unclear. A middle cerebral artery occlusion and reperfusion (MCAO-R) model was used in the present study. The animals were treated with BHD (5, 10 and 20 g/kg) or rapamycin. Infarct size and modified neurological severity score were calculated on day 5 following MCAO-R surgery. Cellular changes around the ischemic penumbra were revealed by hematoxylin and eosin and Nissl staining. The protein expression levels of nestin, brain-derived neurotrophic factor (BDNF), doublecortin on the X chromosome (DCX) and autophagy-related proteins (beclin 1, LC3-II and p62) in the peri-ischemic area of the brain were detected. The results demonstrated that post-surgical treatment with BHD reduced the brain infarct size and improved neurological deficits in MCAO-R rats. BHD protected against MCAO-R-induced neuronal impairment and promoted neurogenesis, increased the protein expression of nestin, BDNF and DCX and markedly enhanced autophagy by increasing beclin 1 and LC3-II and decreasing p62. Meanwhile, BHD promoted the expression of sirtuin 1 (SIRT1), an important regulator of autophagy. In conclusion, the present study suggested that post-surgical treatment with BHD could protect rat brains from I/R injury, potentially through the SIRT1/autophagy pathway.

Bone Marrow Mesenchymal Stem Cells Exert Protective Effects After Ischemic Stroke Through Upregulation of Glutathione

Bone marrow mesenchymal stem cells (BMSCs) have been shown to promote stroke recovery, however, the underlying mechanisms are not well understood. In this study naïve rats were intravenously injected with syngeneic BMSCs to screen for potential differences in brain metabolite spectrum versus vehicle-treated controls by capillary electrophoresis-mass spectrometry. A total of 65 metabolites were significantly changed after BMSC treatment. Among them, 5-oxoproline, an intermediate in the biosynthesis of the endogenous glutathione (GSH), was increased. To confirm the obtained results and investigate the metabolic pathways, BMSCs were injected into rats 24 h after middle cerebral artery occlusion (MCAO). Rats receiving vehicle solution and sham-operated animals served as controls. High performance liquid chromatography, reverse transcription-quantitative polymerase chain reaction, and Western blotting revealed that intravenous BMSC application increased the levels of 5-oxoproline and GSH in MCAO rats, as well as the expression of key enzymes involved in GSH synthesis including, gamma-glutamylcyclotransferase and gamma-glutamylcysteine ligase. Subsequent clinical investigation confirmed that acute ischemic stroke patients had higher plasma 5-oxoproline and GSH levels than age- and sex-matched non-stroke controls. The optimal cutoff value for 5-oxoproline diagnosing acute ischemic stroke (≤ 7d) was 3.127 µg/mL (sensitivity, 63.4 %; specificity, 81.2 %) determined by receiver characteristic operator curve. The area under the curve was 0.782 (95 % confidence interval: 0.718-0.845). Our findings indicate that BMSCs play a protective role in ischemic stroke through upregulation of GSH and 5-oxoproline is a potential biomarker for acute ischemic stroke. Ischemic stroke causes oxidative stress and induction of endogenous, glutathione-dependent anti-oxidative mechanisms. 5-oxoproline, an important metabolite in glutathione biosynthesis, could serve as a biomarker of acute ischemic stroke. Moreover, intravenous bone marrow mesenchymal stem cell (BMSC) treatment after experimental stroke upregulates the expression of key enzymes involved in glutathione synthesis, which results in better antioxidative defense and improved stroke outcome.

Scoping Review of Clinical Practice Guidelines for the Early Management of Stroke with Focus on Endovascular Treatment

BACKGROUND

Stroke represents one of the major causes of death and long-term disability worldwide and, even when new treatment strategies have been identified, there is a need of quality clinical practice guidelines (CPGs) to guide and improve acute stroke care. We aim to describe the characteristics and assess the quality of CPGs in endovascular treatment for acute ischemic stroke due to anterior-circulation large-vessel occlusion.

METHODS

We conducted a scoping review of CPGs that assessed stroke management. We searched the following databases: PubMed, TripDatabase, Scopus, and Google Scholar to identify CPGs published or updated in the last 3 years and used Appraisal of Guidelines Research and Evaluation II to assess the quality of the guidelines.

RESULTS

We found a total of 9 CPGs published or updated between 2018 and 2020, from which only one third had adequate methodologic rigor. Guidelines presented pitfalls related to evidence search, assessment, and methods used to reach the recommendations. All the CPGs considered a 24-hour extended window of treatment and the CPGs considered the use of similar imaging techniques to diagnose and explore the extent of the stroke. However, there were variations regarding the selection criteria for thrombectomy.

CONCLUSIONS

The quality of the CPGs varied widely, which issues around the identification and assessment of the evidence used to reach recommendations. Despite this, the recommendations regarding the use of thrombectomy were similar across the CPGs. Readers need to carefully assess the methodologic rigor of CPGs before applying them to their clinical practice.

In vivo Cell Tracking Using Non-invasive Imaging of Iron Oxide-Based Particles with Particular Relevance for Stem Cell-Based Treatments of Neurological and Cardiac Disease

Stem cell-based therapeutics is a rapidly developing field associated with a number of clinical challenges. One such challenge lies in the implementation of methods to track stem cells and stem cell-derived cells in experimental animal models and in the living patient. Here, we provide an overview of cell tracking in the context of cardiac and neurological disease, focusing on the use of iron oxide-based particles (IOPs) visualized in vivo using magnetic resonance imaging (MRI). We discuss the types of IOPs available for such tracking, their advantages and limitations, approaches for labeling cells with IOPs, biological interactions and effects of IOPs at the molecular and cellular levels, and MRI-based and associated approaches for in vivo and histological visualization. We conclude with reviews of the literature on IOP-based cell tracking in cardiac and neurological disease, covering both preclinical and clinical studies.

p53 Inhibition Provides a Pivotal Protective Effect against Cerebral Ischemia-Reperfusion Injury via the Wnt Signaling Pathway

INTRODUCTION

Cerebral ischemia-reperfusion injury enhances brain injury and increases its morbidity and mortality. The purpose of our study was to further explore the specific pathogenesis of cerebral ischemia disease by studying the role of p53 in cerebral ischemia-reperfusion injury and its mechanism to provide a new target for the treatment of cerebral ischemia.

METHODS

Middle cerebral artery occlusion (MCAo) was established in rats. The changes in p53 and apoptotic proteins in the rat model were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. The effects of p53 inhibitors on cerebral is-chemia-reperfusion injury in rats were evaluated by modified neurological severity score (mNSS) and infarct area. Subsequently, neural stem cells (NSCs) were isolated and cultured in vitro, and oxygen and glucose deprivation (OGD) was induced to establish an in vitro ischemia-reperfusion injury model. Cell viability and migration were detected by CCK-8 and transwell assays. Apoptosis of NSCs was detected by flow cytometry. Finally, protein expression in the Wnt pathway activated by p53 was detected by Western blotting.

RESULTS

Compared with the sham group, p53 levels, mNSS, cerebral infarction area, and apoptosis were significantly increased in the MCAo group (p < 0.05). When the p53 inhibitor PFT-α was injected, the increase in these levels was reversed. Also, the viability and migration of cells decreased and apo-ptosis increased in the in vitro OGD model, whereas the viability, migration, and apoptosis were significantly reversed after the addition of p53 inhibitors (p < 0.05). Finally, p53 induced Wnt signaling pathway proteins β-catenin and cyclin D1 decrease in the MCAo group, while p53 inhibitors reversed their inhibitory effect on the Wnt signaling pathway.

CONCLUSION

We confirmed in vivo and in vitro that inhibition of p53 has a protective effect on the cerebral ischemia-reperfusion injury, which may be related to the activation of the Wnt signaling pathway.

Calcium/Calmodulin-Dependent Protein Kinase II in Cerebrovascular Diseases

Cerebrovascular disease is the most common life-threatening and debilitating condition that often leads to stroke. The multifunctional calcium/calmodulin-dependent protein kinase II (CaMKII) is a key Ca2+ sensor and an important signaling protein in a variety of biological systems within the brain, heart, and vasculature. In the brain, past stroke-related studies have been mainly focused on the role of CaMKII in ischemic stroke in neurons and established CaMKII as a major mediator of neuronal cell death induced by glutamate excitotoxicity and oxidative stress following ischemic stroke. However, with growing understanding of the importance of neurovascular interactions in cerebrovascular diseases, there are clearly gaps in our understanding of how CaMKII functions in the complex neurovascular biological processes and its contributions to cerebrovascular diseases. Additionally, emerging evidence demonstrates novel regulatory mechanisms of CaMKII and potential roles of the less-studied CaMKII isoforms in the ischemic brain, which has sparked renewed interests in this dynamic kinase family. This review discusses past findings and emerging evidence on CaMKII in several major cerebrovascular dysfunctions including ischemic stroke, hemorrhagic stroke, and vascular dementia, focusing on the unique roles played by CaMKII in the underlying biological processes of neuronal cell death, neuroinflammation, and endothelial barrier dysfunction triggered by stroke. We also highlight exciting new findings, promising therapeutic agents, and future perspectives for CaMKII in cerebrovascular systems.

The functions of repressor element 1-silencing transcription factor in models of epileptogenesis and post-ischemia

Epilepsy is a debilitating neurological disorder characterised by recurrent seizures for which 30% of patients are refractory to current treatments. The genetic and molecular aetiologies behind epilepsy are under investigation with the goal of developing new epilepsy medications. The transcriptional repressor REST (Repressor Element 1-Silencing Transcription factor) is a focus of interest as it is consistently upregulated in epilepsy patients and following brain insult in animal models of epilepsy and ischemia. This review analyses data from different epilepsy models and discusses the contribution of REST to epileptogenesis. We propose that in healthy brains REST acts in a protective manner to homeostatically downregulate increases in excitability, to protect against seizure through downregulation of BDNF (Brain-Derived Neurotrophic Factor) and its receptor, TrkB (Tropomyosin receptor kinase B). However, in epilepsy patients and post-seizure, REST may increase to a larger degree, which allows downregulation of the glutamate receptor subunit GluR2. This leads to AMPA glutamate receptors lacking GluR2 subunits, which have increased permeability to Ca²⁺, causing excitotoxicity, cell death and seizure. This concept highlights therapeutic potential of REST modulation through gene therapy in epilepsy patients.

Repetitive transcranial magnetic stimulation increases neurological function and endogenous neural stem cell migration via the SDF-1α/CXCR4 axis after cerebral infarction in rats

Neural stem cell (NSC) migration is closely associated with brain development and is reportedly involved during recovery from ischaemic stroke. Chemokine signalling mediated by stromal cell-derived factor 1α (SDF-1α) and its receptor CXC chemokine receptor 4 (CXCR4) has been previously documented to guide the migration of NSCs. Although repetitive transcranial magnetic stimulation (rTMS) can increase neurological function in a rat stroke model, its effects on the migration of NSCs and associated underlying mechanism remain unclear. Therefore, the present study investigated the effects of rTMS on ischaemic stroke following middle cerebral artery occlusion (MCAO). All rats underwent rTMS treatment 24 h after MCAO. Neurological function, using modified Neurological Severity Scores and grip strength test and NSC migration, which were measured using immunofluorescence staining, were analysed at 7 and 14 days after MCAO, before the protein expression levels of the SDF-1α/CXCR4 axis was evaluated using western blot analysis. AMD3100, a CXCR4 inhibitor, was used to assess the effects of SDF-1α/CXCR4 signalling. In addition, neuronal survival was investigated using Nissl staining at 14 days after MCAO. It was revealed that rTMS increased the neurological recovery of rats with MCAO, facilitated the migration of NSC, augmented the expression levels of the SDF-1α/CXCR4 axis and decreased neuronal loss. Furthermore, the rTMS-induced positive responses were significantly abolished by AMD3100. Overall, these results indicated that rTMS conferred therapeutic neuroprotective properties, which can restore neurological function after ischaemic stroke, in a manner that may be associated with the activation of the SDF-1α/CXCR4 axis.

miRNA-132/212 Gene-Deletion Aggravates the Effect of Oxygen-Glucose Deprivation on Synaptic Functions in the Female Mouse Hippocampus

Cerebral ischemia and its sequelae, which include memory impairment, constitute a leading cause of disability worldwide. Micro-RNAs (miRNA) are evolutionarily conserved short-length/noncoding RNA molecules recently implicated in adaptive/maladaptive neuronal responses to ischemia. Previous research independently implicated the miRNA-132/212 cluster in cholinergic signaling and synaptic transmission, and in adaptive/protective mechanisms of neuronal responses to hypoxia. However, the putative role of miRNA-132/212 in the response of synaptic transmission to ischemia remained unexplored. Using hippocampal slices from female miRNA-132/212 double-knockout mice in an established electrophysiological model of ischemia, we here describe that miRNA-132/212 gene-deletion aggravated the deleterious effect of repeated oxygen-glucose deprivation insults on synaptic transmission in the dentate gyrus, a brain region crucial for learning and memory functions. We also examined the effect of miRNA-132/212 gene-deletion on the expression of key mediators in cholinergic signaling that are implicated in both adaptive responses to ischemia and hippocampal neural signaling. miRNA-132/212 gene-deletion significantly altered hippocampal AChE and mAChR-M1, but not α7-nAChR or MeCP2 expression. The effects of miRNA-132/212 gene-deletion on hippocampal synaptic transmission and levels of cholinergic-signaling elements suggest the existence of a miRNA-132/212-dependent adaptive mechanism safeguarding the functional integrity of synaptic functions in the acute phase of cerebral ischemia.

Caveolin-1, a novel player in cognitive decline

Cognitive decline (CD), which related to vascular dementia, Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis and diabetes mellitus, is a growing health concern that has a great impact on the patients' quality of life. Although extensive efforts, the mechanisms of CD are still far from being clarified, not to mention the effective treatment and prevention strategies. Caveolin-1 (Cav-1), a trans-membrane protein, is a major component of the caveolae structure and scaffolding proteins. Recently, ample evidence depicts a strong correlation between Cav-1 and CD, however, the specific role of Cav-1 in CD has not been clearly examined and how they might be connected have yet to be identified. This review seeks to provide a comprehensive overview about how Cav-1 modulates pathogeneses of CD-associated diseases. In summary, Cav-1 can promote structural and functional plasticity of neurons, improve neurogenesis, relieve mitochondrial dysfunction, inhibit inflammation and suppress oxidative stress, which have shed light on the idea that Cav-1 may be an efficacious therapeutic target to treat CD.