miR-195 Has a Potential to Treat Ischemic and Hemorrhagic Stroke through Neurovascular Protection and Neurogenesis

The role of nanomaterials in revolutionizing ischemic stroke treatment: Current trends and future prospects

Ischemic stroke has a high disability rate, which leads to irreversible neuronal death. The efficacy of conventional stroke treatments, including thrombolytic and neuroprotective therapies, is constrained by a number of factors, including safety concerns and inefficient drug delivery. The advent of nanomaterials has created new avenues for stroke therapy, facilitating enhanced pharmacokinetic behavior of drugs, effective drug accumulation at the target site, augmented therapeutic efficacy, and concomitant reduction in side effects. Therefore, this paper pioneers a research approach that summarized the development trend and clinical value of nanomaterials in the field of ischemic stroke through bibliometric analysis. This review provides an overview of the pathophysiological mechanisms of stroke and examines the current research trends in the use of nanomaterials in stroke management. It encompasses a multitude of domains, including targeted drug delivery systems, biosensors for the sensitive detection of biomarkers, and neuroprotective nanotechnologies capable of traversing the blood-brain barrier. Moreover, we investigate the challenges that nanomaterials encounter in the clinical translation context, including those pertaining to biocompatibility and long-term safety. These results have provided the clinical value and limitations of nanomaterials in the diagnosis and treatment of ischemic stroke from double perspectives, thereby offering new avenues for the further development of innovative nanotherapeutic tools.

Advantages and disadvantages of targeting senescent endothelial cells in cardiovascular and cerebrovascular diseases based on small extracellular vesicles

INTRODUCTION

With the growth of the aging population, age-related diseases have become a heavy global burden, particularly cardiovascular and cerebrovascular diseases (CVDs). Endothelial cell (EC) senescence constitutes an essential factor in the development of CVDs, prompting increased focus on strategies to alleviate or reverse EC senescence.

AREAS COVERED

Small extracellular vesicles (sEVs) are cell-derived membrane structures, that contain proteins, lipids, RNAs, metabolites, growth factors and cytokines. They are widely used in treating CVDs, and show remarkable therapeutic potential in alleviating age-related CVDs by inhibiting or reversing EC senescence. However, unclear anti-senescence mechanism poses challenges for clinical application of sEVs, and a systematic review is lacking.

EXPERT OPINION

Targeting senescent ECs with sEVs in age-related CVDs treatment represents a promising therapeutic strategy, with modifying sEVs and their contents emerging as a prevalent approach. Nevertheless, challenges remain, such as identifying and selectively targeting senescent cells, understanding the consequences of removing senescent ECs and senescence-associated secretory phenotype (SASP), and assessing the side effects of therapeutic sEVs on CVDs. More substantial experimental and clinical data are needed to advance clinical practice.

Exploring the correlation between innate immune activation of inflammasome and regulation of pyroptosis after intracerebral hemorrhage: From mechanism to treatment

Stroke has emerged as the primary cause of disability and death globally in recent years. Intracerebral hemorrhage (ICH), a particularly severe kind of stroke, is occurring in an increasing number of people. The two main clinical treatments for ICH now in use are conservative pharmaceutical therapy and surgical intervention, both of which have risks and drawbacks. Consequently, it is crucial to look into the pathophysiology of ICH and consider cutting-edge therapeutic approaches. Recent research has revealed that pyroptosis is a newly identified type of cell death distinguished by the break of the cell membrane and the discharge of pro-inflammatory substances through different routes. Following ICH, glial cells experience pyroptosis, which worsens neuroinflammation. Hence, the onset and progression of ICH are strongly linked to pyroptosis, which is facilitated by different inflammasomes. It is essential to conduct a comprehensive investigation of ICH damage processes and uncover new targets for treatment. The impact and function of pyroptosis in ICH, as well as the activation and regulation of inflammasomes and their mediated pyroptosis pathways will be fully discussed in this review.

Survival of Ischaemic and Haemorrhagic Stroke: Analysis of the Malaysian National Stroke Registry Data from 2009 to 2013

Background

Stroke ranks as the second leading cause of death globally, contributing to 15.2 million deaths in 2016. In Malaysia, stroke has emerged as a significant cause of mortality and disability. This study aims to evaluate the survival time and rate of stroke patients in Malaysia.

Methods

In this retrospective cohort study, we reviewed secondary data from the National Stroke Registry (NSR) of Malaysia. The study included all Malaysian residents over the age of 12 years old diagnosed with either ischaemic or haemorrhagic stroke between 1 January 2009 and 31 December 2013. Patients with a transient ischaemic attack were excluded. We updated the death status up to 31 December 2018 using mortality data from the Malaysian National Registry Department. We used Kaplan-Meier Survival Analysis to determine the overall median survival time and log-rank test to compare the median time by ethnicity, sex and stroke type. The survival rates at 1 year, 3 years and 5 years were obtained using the life-table method.

Results

The analysis included a total of 5,777 stroke patients. The mean age at diagnosis was 63.15 years old (with a standard deviation of 12.46 years old). The overall median survival time was 51 months (95% CI: 47.4, 54.6). Non-Malay patients and those with ischaemic strokes experienced a longer median survival time (65.2 months [95% CI: 56.6, 73.7] and 56.3 months [95% CI: 52.2, 60.3]), respectively. The survival rates at 1 year, 3 years and 5 years were 66.7% (95% CI: 65.5%, 68.0%), 55.6% (95% CI: 54.3%, 56.9%) and 46.9% (95% CI: 45.6%, 48.2%), respectively.

Conclusion

There are significant differences in median survival time in relation to ethnicity and stroke types. Compared to other developed countries, Malaysia's 5-year survival rate is notably lower.

Expression Levels and Clinical Values of miR-195, miR-424, miR-10b, miR-103a-3p, and miR-542-3p in Vasculo-Behçet's Disease

Objective

MicroRNAs (miRNAs) are involved in a range of pathological and biological processes. Vascular involvement is an important complication associated with morbidity and mortality in Behçet's disease (BD). In this study, we aimed to evaluate the expression levels of miR-195, miR-424, miR-10b, miR-103a-3p, and miR-542-3p in Turkish patients with BD, and their possible association with vascular involvement and clinical activity.

Methods

This cross-sectional study included 61 BD patients and 25 age- and sex-matched healthy individuals. The patients were categorised into two groups based on the presence or absence of vascular involvement. Demographic data, disease duration, disease activity, and medical treatments were recorded. Disease activity was evaluated using the Behçet's Disease Current Activity Form (BDCAF) and the Behçet's Syndrome Activity Scale (BSAS). The expression levels of miRNAs were measured using real-time quantitative polymerase chain reaction (RT-qPCR).

Results

The comparison of the clinical features of BD patients with and without vascular involvement revealed no significant difference. However, the expression levels of miR-195, miR-424, miR-10b, miR-103a-3p, and miR-542-3p were significantly higher in BD patients than in healthy controls (p<0.001, p<0.001, p=0.010, p<0.01, p=0.039, respectively). Moreover, the expression level of miR-195 was significantly higher in vasculo-Behçet patients than in the other groups (p=0.0318). However, no significant association was found between the expression levels of miR-195 and clinical activity.

Conclusion

Our study results indicated elevated serum levels of miR-195 in BD patients, which may be associated with vascular involvement. Therefore, miR-195 could potentially serve as a biomarker for the diagnosis and monitoring of vasculo-Behçet's disease.

Out of the core: the impact of focal ischemia in regions beyond the penumbra

The changes in the necrotic core and the penumbra following induction of focal ischemia have been the focus of attention for some time. However, evidence shows, that ischemic injury is not confined to the primarily affected structures and may influence the remote areas as well. Yet many studies fail to probe into the structures beyond the penumbra, and possibly do not even find any significant results due to their short-term design, as secondary damage occurs later. This slower reaction can be perceived as a therapeutic opportunity, in contrast to the ischemic core defined as irreversibly damaged tissue, where the window for salvation is comparatively short. The pathologies in remote structures occur relatively frequently and are clearly linked to the post-stroke neurological outcome. In order to develop efficient therapies, a deeper understanding of what exactly happens in the exo-focal regions is necessary. The mechanisms of glia contribution to the ischemic damage in core/penumbra are relatively well described and include impaired ion homeostasis, excessive cell swelling, glutamate excitotoxic mechanism, release of pro-inflammatory cytokines and phagocytosis or damage propagation via astrocytic syncytia. However, little is known about glia involvement in post-ischemic processes in remote areas. In this literature review, we discuss the definitions of the terms "ischemic core", "penumbra" and "remote areas." Furthermore, we present evidence showing the array of structural and functional changes in the more remote regions from the primary site of focal ischemia, with a special focus on glia and the extracellular matrix. The collected information is compared with the processes commonly occurring in the ischemic core or in the penumbra. Moreover, the possible causes of this phenomenon and the approaches for investigation are described, and finally, we evaluate the efficacy of therapies, which have been studied for their anti-ischemic effect in remote areas in recent years.

Plasma miR-195-5p predicts the severity of Covid-19 in hospitalized patients

Predicting the clinical course of Covid-19 is a challenging task, given the multi-systemic character of the disease and the paucity of minimally invasive biomarkers of disease severity. Here, we evaluated the early (first two days post-admission) level of circulating hsa-miR-195-5p (miR-195, a known responder to viral infections and SARS-CoV-2 interactor) in Covid-19 patients and assessed its potential as a biomarker of disease severity. We show that plasma miR-195 correlates with several clinical and paraclinical parameters, and is an excellent discriminator between the severe and mild forms of the disease. Our Gene Ontology analysis of miR-195 targets differentially expressed in Covid-19 indicates a strong impact on cardiac mitochondria homeostasis, suggesting a possible role in long Covid and chronic fatigue syndrome (CFS) syndromes.

Role and regulatory mechanism of microRNA mediated neuroinflammation in neuronal system diseases

MicroRNAs (miRNAs) are small non-coding RNAs with the unique ability to degrade or block specific RNAs and regulate many cellular processes. Neuroinflammation plays the pivotal role in the occurrence and development of multiple central nervous system (CNS) diseases. The ability of miRNAs to enhance or restrict neuroinflammatory signaling pathways in CNS diseases is an emerging and important research area, including neurodegenerative diseases, stroke, and traumatic brain injury (TBI). In this review, we summarize the roles and regulatory mechanisms of recently identified miRNAs involved in neuroinflammation-mediated CNS diseases, aiming to explore and provide a better understanding and direction for the treatment of CNS diseases.

Nanoparticle-mediated delivery of microRNAs-based therapies for treatment of disorders

miRNAs represent appropriate candidates for treatment of several disorders. However, safe and efficient delivery of these small-sized transcripts has been challenging. Nanoparticle-based delivery of miRNAs has been used for treatment of a variety of disorders, particularly cancers as well as ischemic stroke and pulmonary fibrosis. The wide range application of this type of therapy is based on the important roles of miRNAs in the regulation of cell behavior in physiological and pathological conditions. Besides, the ability of miRNAs to inhibit or increase expression of several genes gives them the superiority over mRNA or siRNA-based therapies. Preparation of nanoparticles for miRNA delivery is mainly achieved through using protocols originally developed for drugs or other types of biomolecules. In brief, nanoparticle-based delivery of miRNAs is regarded as a solution for overcoming all challenges in the therapeutic application of miRNAs. Herein, we provide an overview of studies which used nanoparticles as delivery systems for facilitation of miRNAs entry into target cells for the therapeutic purposes. However, our knowledge about miRNA-loaded nanoparticles is limited, and it is expected that numerous therapeutic possibilities will be revealed for miRNA-loaded nanoparticles in future.

MicroRNA-based therapeutics for inflammatory disorders of the microbiota-gut-brain axis

An emerging but less explored shared pathophysiology across microbiota-gut-brain axis disorders is aberrant miRNA expression, which may represent novel therapeutic targets. miRNAs are small, endogenous non-coding RNAs that are important transcriptional repressors of gene expression. Most importantly, they regulate the integrity of the intestinal epithelial and blood-brain barriers and serve as an important communication channel between the gut microbiome and the host. A well-defined understanding of the mode of action, therapeutic strategies and delivery mechanisms of miRNAs is pivotal in translating the clinical applications of miRNA-based therapeutics. Accumulating evidence links disorders of the microbiota-gut-brain axis with a compromised gut-blood-brain-barrier, causing gut contents such as immune cells and microbiota to enter the bloodstream leading to low-grade systemic inflammation. This has the potential to affect all organs, including the brain, causing central inflammation and the development of neurodegenerative and neuropsychiatric diseases. In this review, we have examined in detail miRNA biogenesis, strategies for therapeutic application, delivery mechanisms, as well as their pathophysiology and clinical applications in inflammatory gut-brain disorders. The research data in this review was drawn from the following databases: PubMed, Google Scholar, and Clinicaltrials.gov. With increasing evidence of the pathophysiological importance for miRNAs in microbiota-gut-brain axis disorders, therapeutic targeting of cross-regulated miRNAs in these disorders displays potentially transformative and translational potential. Further preclinical research and human clinical trials are required to further advance this area of research.

Cerebral Semaphorin3D is a novel risk factor for age-associated cognitive impairment

BACKGROUND

We previously reported that miR-195 exerts neuroprotection by inhibiting Sema3A and cerebral miR-195 levels decreased with age, both of which urged us to explore the role of miR-195 and miR-195-regulated Sema3 family members in age-associated dementia.

METHODS

miR-195a KO mice were used to assess the effect of miR-195 on aging and cognitive functions. Sema3D was predicted as a miR-195 target by TargetScan and then verified by luciferase reporter assay, while effects of Sema3D and miR-195 on neural senescence were assessed by beta-galactosidase and dendritic spine density. Cerebral Sema3D was over-expressed by lentivirus and suppressed by si-RNA, and effects of over-expression of Sema3D and knockdown of miR-195 on cognitive functions were assessed by Morris Water Maze, Y-maze, and open field test. The effect of Sema3D on lifespan was assessed in Drosophila. Sema3D inhibitor was developed using homology modeling and virtual screening. One-way and two-way repeated measures ANOVA were applied to assess longitudinal data on mouse cognitive tests.

RESULTS

Cognitive impairment and reduced density of dendritic spine were observed in miR-195a knockout mice. Sema3D was identified to be a direct target of miR-195 and a possible contributor to age-associated neurodegeneration as Sema3D levels showed age-dependent increase in rodent brains. Injection of Sema3D-expressing lentivirus caused significant memory deficits while silencing hippocampal Sema3D improved cognition. Repeated injections of Sema3D-expressing lentivirus to elevate cerebral Sema3D for 10 weeks revealed a time-dependent decline of working memory. More importantly, analysis of the data on the Gene Expression Omnibus database showed that Sema3D levels were significantly higher in dementia patients than normal controls (p < 0.001). Over-expression of homolog Sema3D gene in the nervous system of Drosophila reduced locomotor activity and lifespan by 25%. Mechanistically, Sema3D might reduce stemness and number of neural stem cells and potentially disrupt neuronal autophagy. Rapamycin restored density of dendritic spines in the hippocampus from mice injected with Sema3D lentivirus. Our novel small molecule increased viability of Sema3D-treated neurons and might improve autophagy efficiency, which suggested Sema3D could be a potential drug target. Video Abstract CONCLUSION: Our results highlight the importance of Sema3D in age-associated dementia. Sema3D could be a novel drug target for dementia treatment.

Mechanism of ligusticum cycloprolactam against neuroinflammation based on network pharmacology and experimental verification

Ligustilide, a natural phthalide mainly derived from chuanxiong rhizomes and Angelica Sinensis roots, possesses anti-inflammatory activity, particularly in the context of the nervous system. However, its application is limited because of its unstable chemical properties. To overcome this limitation, ligusticum cycloprolactam (LIGc) was synthesized through structural modification of ligustilide. In this study, we combined network pharmacological methods with experimental verification to investigate the anti-neuroinflammatory effects and mechanisms of ligustilide and LIGc. Based on our network pharmacology analysis, we identified four key targets of ligustilide involved in exerting an anti-inflammatory effect, with the nuclear factor (NF)-κB signal pathway suggested as the main signalling pathway. To verify these results, we examined the expression of inflammatory cytokines and inflammation-related proteins, analysed the phosphorylation level of NF-κB, inhibitor of κBα (IκBα) and inhibitor of κB kinase α and β (IKKα+β), and evaluated the effect of BV2 cell-conditioned medium on HT22 cells in vitro. Our results, demonstrate for the first time that LIGc can downregulate the activation of the NF-κB signal pathway in BV2 cells induced by lipopolysaccharide, suppress the production of inflammatory cytokines and reduce nerve injury in HT22 cells mediated by BV2 cells. These findings suggest that LIGc inhibits the neuroinflammatory response mediated by BV2 cells, providing strong scientific support for the development of anti-inflammatory drugs based on natural ligustilide or its derivatives. However, there are some limitations to our current study. In the future, further experiments using in vivo models may provide additional evidence to support our findings.

CDC42 Might Be a Molecular Signature of DWI-FLAIR Mismatch in a Nonhuman Primate Stroke Model

No definitive blood markers of DWI-FLAIR mismatch, a pivotal indicator of salvageable ischemic penumbra brain tissue, are known. We previously reported that CDC42 and RHOA are associated with the ischemic penumbra. Here, we investigated whether plasma CDC42 and RHOA are surrogate markers of DWI-FLAIR mismatch. Sixteen cynomolgus macaques (3 as controls and 13 for the stroke model) were included. Guided by digital subtraction angiography (DSA), a middle cerebral artery occlusion (MCAO) model was established by occluding the middle cerebral artery (MCA) with a balloon. MRI and neurological deficit scoring were performed to evaluate postinfarction changes. Plasma CDC42 and RHOA levels were measured by enzyme-linked immunosorbent assay (ELISA). The stroke model was successfully established in eight monkeys. Based on postinfarction MRI images, experimental animals were divided into a FLAIR (-) group (N = 4) and a FLAIR (+) group (N = 4). Plasma CDC42 in the FLAIR (-) group showed a significant decrease compared with that in the FLAIR (+) group (p < 0.05). No statistically significant difference was observed for plasma RHOA. The FLAIR (-) group showed a milder neurological function deficit and a smaller infarct volume than the FLAIR (+) group (p < 0.05). Therefore, plasma CDC42 might be a new surrogate marker for DWI-FLAIR mismatch.

Nanoparticle and Stem Cell Combination Therapy for the Management of Stroke

Stroke is currently one of the primary causes of morbidity and mortality worldwide. Unfortunately, the available treatments for stroke are still extremely limited. Indeed, stem cell (SC) therapy is a new option for the treatment of stroke that could significantly expand the therapeutic time window of stroke. Some proposed mechanisms for stroke-based SC therapy are the incorporation of SCs into the host brain to replace dead or damaged cells/tissues. Moreover, acute cell delivery can inhibit apoptosis and decrease lesion size, providing immunomudolatory and neuroprotection effects. However, several major SC problems related to SCs such as homing, viability, uncontrolled differentiation, and possible immune response, have limited SC therapy. A combination of SC therapy with nanoparticles (NPs) can be a solution to address these challenges. NPs have received considerable attention in regulating and controlling the behavior of SCs because of their unique physicochemical properties. By reviewing the pathophysiology of stroke and the therapeutic benefits of SCs and NPs, we hypothesize that combined therapy will offer a promising future in the field of stroke management. In this work, we discuss recent literature in SC research combined with NP-based strategies that may have a synergistic outcome after stroke incidence.

LncRNA MEG3: Potential stock for precision treatment of cardiovascular diseases

The prevalence and mortality rates of cardiovascular diseases are increasing, and new treatment strategies are urgently needed. From the perspective of basic pathogenesis, the occurrence and development of cardiovascular diseases are related to inflammation, apoptosis, fibrosis and autophagy of cardiomyocytes, endothelial cells and other related cells. The involvement of maternally expressed gene 3 (MEG3) in human disease processes has been increasingly reported. P53 and PI3K/Akt are important pathways by which MEG3 participates in regulating cell apoptosis. MEG3 directly or competitively binds with miRNA to participate in apoptosis, inflammation, oxidative stress, endoplasmic reticulum stress, EMT and other processes. LncRNA MEG3 is mainly involved in malignant tumors, metabolic diseases, immune system diseases, cardiovascular and cerebrovascular diseases, etc., LncRNA MEG3 has a variety of pathological effects in cardiomyocytes, fibroblasts and endothelial cells and has great clinical application potential in the prevention and treatment of AS, MIRI, hypertension and HF. This paper will review the research progress of MEG3 in the aspects of mechanism of action, other systemic diseases and cardiovascular diseases, and point out its great potential in the prevention and treatment of cardiovascular diseases. lncRNAs also play a role in endothelial cells. In addition, lncRNA MEG3 has shown biomarker value, prognostic value and therapeutic response measurement in tumor diseases. We boldly speculate that MEG3 will play a role in the emerging discipline of tumor heart disease.

MicroRNAs modulate neuroinflammation after intracerebral hemorrhage: Prospects for new therapy

Intracerebral hemorrhage (ICH) is the most common subtype of hemorrhagic stroke. After ICH, blood components extravasate from vessels into the brain, activating immune cells and causing them to release a series of inflammatory mediators. Immune cells, together with inflammatory mediators, lead to neuroinflammation in the perihematomal region and the whole brain, and neuroinflammation is closely related to secondary brain injury as well as functional recovery of the brain. Despite recent progress in understanding the pathophysiology of ICH, there is still no effective treatment for this disease. MicroRNAs (miRNAs) are non-coding RNAs 17-25 nucleotides in length that are generated naturally in the human body. They bind complementarily to messenger RNAs and suppress translation, thus regulating gene expression at the post-transcriptional level. They have been found to regulate the pathophysiological process of ICH, particularly the neuroinflammatory cascade. Multiple preclinical studies have shown that manipulating the expression and activity of miRNAs can modulate immune cell activities, influence neuroinflammatory responses, and ultimately affect neurological functions after ICH. This implicates the potentially crucial roles of miRNAs in post-ICH neuroinflammation and indicates the possibility of applying miRNA-based therapeutics for this disease. Thus, this review aims to address the pathophysiological roles and molecular underpinnings of miRNAs in the regulation of neuroinflammation after ICH. With a more sophisticated understanding of ICH and miRNAs, it is possible to translate these findings into new pharmacological therapies for ICH.

Delivering the Promise of Gene Therapy with Nanomedicines in Treating Central Nervous System Diseases

Central Nervous System (CNS) diseases, such as Alzheimer's diseases (AD), Parkinson's Diseases (PD), brain tumors, Huntington's disease (HD), and stroke, still remain difficult to treat by the conventional molecular drugs. In recent years, various gene therapies have come into the spotlight as versatile therapeutics providing the potential to prevent and treat these diseases. Despite the significant progress that has undoubtedly been achieved in terms of the design and modification of genetic modulators with desired potency and minimized unwanted immune responses, the efficient and safe in vivo delivery of gene therapies still poses major translational challenges. Various non-viral nanomedicines have been recently explored to circumvent this limitation. In this review, an overview of gene therapies for CNS diseases is provided and describes recent advances in the development of nanomedicines, including their unique characteristics, chemical modifications, bioconjugations, and the specific applications that those nanomedicines are harnessed to deliver gene therapies.

Nanoparticles in the diagnosis and treatment of vascular aging and related diseases

Aging-induced alternations of vasculature structures, phenotypes, and functions are key in the occurrence and development of vascular aging-related diseases. Multiple molecular and cellular events, such as oxidative stress, mitochondrial dysfunction, vascular inflammation, cellular senescence, and epigenetic alterations are highly associated with vascular aging physiopathology. Advances in nanoparticles and nanotechnology, which can realize sensitive diagnostic modalities, efficient medical treatment, and better prognosis as well as less adverse effects on non-target tissues, provide an amazing window in the field of vascular aging and related diseases. Throughout this review, we presented current knowledge on classification of nanoparticles and the relationship between vascular aging and related diseases. Importantly, we comprehensively summarized the potential of nanoparticles-based diagnostic and therapeutic techniques in vascular aging and related diseases, including cardiovascular diseases, cerebrovascular diseases, as well as chronic kidney diseases, and discussed the advantages and limitations of their clinical applications.

MicroRNA: An Emerging Predictive, Diagnostic, Prognostic and Therapeutic Strategy in Ischaemic Stroke

Stroke continues to be the third-leading cause of death and disability worldwide. The limited availability of diagnostic tools approved therapeutics and biomarkers that help monitor disease progression or predict future events remain as the major challenges in the field of stroke medicine. Hence, attempts to discover safe and efficacious therapeutics and reliable biomarkers are of paramount importance. MicroRNAs (miRNAs) are a class of non-coding RNAs that play important roles in regulating gene expression. Since miRNAs also play important roles in key mechanisms associated with the pathogenesis of stroke, including energy failure, inflammation and cell death, it is possible that miRNAs may serve as reliable blood-based markers for risk prediction, diagnosis and prognosis of ischaemic stroke. Discovery of better neurological outcome and smaller cerebral infarcts in animal models of ischaemic stroke treated with miRNA agomirs or antagomirs indicate that miRNAs may also play a cerebrovascular protective role after an ischaemic stroke. Nonetheless, further evidences on the optimum time for treatment and route of administration are required before effective translation of these findings into clinical practice. Bearing these in mind, this paper reviews the current literature discussing the involvement of miRNAs in major pathologies associated with ischaemic stroke and evaluates their value as reliable biomarkers and therapeutics for ischaemic stroke.

The Profile of Circulating Blood microRNAs in Outpatients with Vulnerable and Stable Atherosclerotic Plaques: Associations with Cardiovascular Risks

Non-coding RNAs reflect many biological processes in the human body, including athero-sclerosis. In a cardiology outpatient department cohort (N = 83), we aimed to compare the levels of circulating microRNAs in groups with vulnerable plaques (N = 22), stable plaques (N = 23) and plaque-free (N = 17) depending on coronary computed tomography angiography and to evaluate associations of microRNA levels with calculated cardiovascular risks (CVR), based on the SCORE2 (+OP), ACC/AHA, ATP-III and MESA scales. Coronary computed tomography was performed on a 640-slice computed tomography scanner. Relative plasma levels of microRNA were assessed via a real-time polymerase chain reaction. We found significant differences in miR-143-3p levels (p = 0.0046 in plaque-free vs. vulnerable plaque groups) and miR-181b-5p (p = 0.0179 in stable vs. vulnerable plaques groups). Analysis of microRNA associations with CVR did not show significant differences for SCORE2 (+OP) and ATPIII scales. MiR-126-5p and miR-150-5p levels were significantly higher (p < 0.05) in patients with ACC/AHA risk >10% and miR-145-5p had linear relationships with ACC/AHA score (adjusted p = 0.0164). The relative plasma level of miR-195 was higher (p < 0.05) in patients with MESA risk > 7.5% and higher (p < 0.05) in patients with zero coronary calcium index (p = 0.036). A linear relationship with coronary calcium was observed for miR-126-3p (adjusted p = 0.0484). A positive correlation with high coronary calcium levels (> 100 Agatson units) was found for miR-181-5p (p = 0.036). Analyzing the biological pathways of these microRNAs, we suggest that miR-143-3p and miR-181-5p can be potential markers of the atherosclerosis process. Other miRNAs (miR-126-3p, 126-5p, 145-5p, 150-5p, 195-5p) can be considered as potential cardiovascular risk modifiers, but it is necessary to validate our results in a large prospective trial.

Circulating miRNA-195-5p and -451a in Patients with Acute Hemorrhagic Stroke in Emergency Department

(1) Background: In our previous study, acute ischemic stroke (AIS) patients showed increased levels of circulating miRNAs (-195-5p and -451a) involved in vascular endothelial growth factor A (VEGF-A) regulation. Here, we evaluated, for the first time, both circulating miRNAs in acute intracerebral hemorrhagic (ICH) patients. (2) Methods: Circulating miRNAs and serum VEGF-A were assessed by real-time PCR and ELISA in 20 acute ICH, 21 AIS patients, and 21 controls. These were evaluated at hospital admission (T0) and after 96 h (T96) from admission. (3) Results: At T0, circulating miRNAs were five-times up-regulated in AIS patients, tending to decrease at T96. By contrast, in the acute ICH group, circulating miRNAs were significantly increased at both T0 and T96. Moreover, a significant decrease was observed in serum VEGF-A levels at T0 in AIS patients, tending to increase at T96. Conversely, in acute ICH patients, the levels of VEGF-A were significantly decreased at both T0 and T96. (4) Conclusions: The absence of a reduction in circulating miRNAs (195-5p and -451a), reported in acute ICH subjects after 96 h from hospital admission, together with the absence of increment of serum VEGF-A, may represent useful biomarkers indicating the severe brain damage status that characterizes acute ICH patients.

Progresses and Prospects of Neuroprotective Agents-Loaded Nanoparticles and Biomimetic Material in Ischemic Stroke

Ischemic stroke remains the leading cause of death and disability, while the main mechanisms of dominant neurological damage in stroke contain excitotoxicity, oxidative stress, and inflammation. The clinical application of many neuroprotective agents is limited mainly due to their inability to cross the blood-brain barrier (BBB), short half-life and low bioavailability. These disadvantages can be better eliminated/reduced by nanoparticle as the carrier of these drugs. This review expounded the currently hot researched nanomedicines from the perspective of the mechanism of ischemic stroke. In addition, this review describes the bionic nanomedicine delivery strategies containing cells, cell membrane vesicles and exosomes that can effectively avoid the risk of clearance by the reticuloendothelial system. The potential challenges and application prospect for clinical translation of these delivery platforms were also discussed.

Novel targets, treatments, and advanced models for intracerebral haemorrhage

Intracerebral haemorrhage (ICH) is the second most common type of stroke and a major cause of mortality and disability worldwide. Despite advances in surgical interventions and acute ICH management, there is currently no effective therapy to improve functional outcomes in patients. Recently, there has been tremendous progress uncovering new pathophysiological mechanisms underlying ICH that may pave the way for the development of therapeutic interventions. Here, we highlight emerging targets, but also existing gaps in preclinical animal modelling that prevent their exploitation. We particularly focus on (1) ICH aetiology, (2) the haematoma, (3) inflammation, and (4) post-ICH pathology. It is important to recognize that beyond neurons and the brain, other cell types and organs are crucially involved in ICH pathophysiology and successful interventions likely will need to address the entire organism. This review will spur the development of successful therapeutic interventions for ICH and advanced animal models that better reflect its aetiology and pathophysiology.

LncRNA ITSN1-2 knockdown inhibits OGD/R-induced inflammation and apoptosis in mouse hippocampal neurons via sponging miR-195-5p

OBJECTIVE

The upregulation of long noncoding RNA intersectin 1-2 (lnc ITSN1-2) is associated with poor prognosis in acute ischemic stroke (AIS) patients, but the role and mechanism of lnc ITSN1-2 in AIS are rarely reported, which, thus, are highlighted in this study.

METHODS

AIS cell model was constructed by oxygen glucose deprivation and reoxygenation (OGD/R). The quantitative real-time PCR was used to detect the expression of lnc ITSN1-2 in HT22 cells. The effects of lnc ITSN1-2 overexpression or knockdown on viability, LDH release, apoptosis, inflammatory and apoptotic factor expressions in OGD/R-induced HT22 cells were measured by cell counting kit-8 assay, LDH release kit, flow cytometry, ELISA and western blot, respectively. Starbase was used to screen the target genes of lnc ITSN1-2. The targeting relationship between lnc ITSN1-2 and miR-195-5p was predicted by starbase and verified by dual-luciferase report assay. The above assays were conducted again to study the function of miR-195-5p. Lastly, the levels of activated mitogen-activated protein kinases (MAPK) pathway-related proteins were determined by western blot.

RESULTS

OGD/R treatment reduced the HT22 cell viability and enhanced LDH release rate and lnc ITSN1-2 expression. Lnc ITSN1-2 overexpression promoted the cell injury, apoptosis and inflammation in OGD/R-induced HT22 cells, while lnc ITSN1-2 knockdown generated the opposite effect and deactivated the MAPK pathways. However, the effect of lnc ITSN1-2 knockdown in OGD/R-induced HT22 cells was reversed by miR-195-5p inhibitor.

CONCLUSION

Lnc ITSN1-2 knockdown suppressed the inflammation and apoptosis in OGD/R-induced HT22 cells by regulating the miR-195-5p-mediated MAPK pathways.

Long non-coding RNA Gm11974 aggravates oxygen-glucose deprivation-induced injury via miR-122-5p/SEMA3A axis in ischaemic stroke

Long non-coding RNAs (lncRNAs) play important roles in ischaemic stroke. This study aimed to investigate the role and potential mechanism of lncRNA Gm11974 in ischaemic stroke. Mouse neuroblastoma N2a cells were treated with oxygen-glucose deprivation (OGD). The levels of Gm11974, microRNA-122-5p (miR-122-5p) and semaphorin 3A (SEMA3A) were detected by quantitative real-time PCR (qRT-PCR) or western blot. Cell viability and apoptosis were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, Caspase-3 Assay Kit and flow Cytometry. The levels of oxidative stress indicators were measured by using commercial kits. The relationship between miR-122-5p and Gm11974 or SEMA3A was verified by dual-luciferase reporter, RNA immunoprecipitation and RNA pull-down assays. Middle cerebral artery occlusion (MCAO) in mice was used to mimic ischaemic stroke. Gm11974 and SEMA3A were up-regulated, while miR-122-5p was down-regulated in OGD-treated N2a cells and MCAO mice. Down-regulation of Gm11974 ameliorated OGD-mediated N2a cell damage by increasing cell viability and reducing cell apoptosis and oxidative stress. Gm11974 promoted OGD-induced injury in N2a cells via negatively regulating miR-122-5p. Also, miR-122-5p alleviated OGD-resulted N2a cell injury by targeting SEMA3A. Moreover, silencing of Gm11974 decreased infarct volume and neurological score in MCAO mice. Knockdown of Gm11974 attenuated neuronal injury in ischaemic stroke by regulating miR-122-5p/SEMA3A signaling pathway.

Therapeutic effect of and mechanisms underlying the effect of miR-195-5p on subarachnoid hemorrhage-induced vasospasm and brain injury in rats

Objectives

There is much evidence suggesting that inflammation contributes majorly to subarachnoid hemorrhage (SAH)-induced cerebral vasospasm and brain injury. miRNAs have been found to modulate inflammation in several neurological disorders. This study investigated the effect of miR-195-5p on SAH-induced vasospasm and early brain injury in experimental rats.

Methods

Ninety-six Sprague-Dawley male rats were randomly and evenly divided into a control group (no SAH, sham surgery), a SAH only group, a SAH + NC-mimic group, and a SAH + miR-195-5p group. SAH was induced using a single injection of blood into the cisterna magna. Suspensions containing NC-mimic and miR-195-5p were intravenously injected into rat tail 30 mins after SAH was induced. We determined degree of vasospasm by averaging areas of cross-sections the basilar artery 24h after SAH. We measured basilar artery endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κ B), phosphorylated NF-κ B (p-NF-κ B), inhibitor of NF-κ B (Iκ Bα) and phosphorylated-Iκ Bα (p-Iκ Bα). Cell death assay was used to quantify the DNA fragmentation, an indicator of apoptotic cell death, in the cortex, hippocampus, and dentate gyrus. Tumor necrosis factor alpha (TNF-α) levels were measured using sample protein obtained from the cerebral cortex, hippocampus and dentate gyrus.

Results

Prior to fixation by perfusion, there were no significant physiological differences among the control and treatment groups. SAH successfully induced vasospasm and early brain injury. MiR-195-5p attenuated vasospasam-induced changes in morphology, reversed SAH-induced elevation of iNOS, p-NF-κ B, NF-κ B, and p-Iκ Bα and reversed SAH-induced suppression of eNOS in the basilar artery. Cell death assay revealed that MiR-195-5p significantly decreased SAH-induced DNA fragmentation (apoptosis) and restored TNF-α level in the dentate gyrus.

Conclusion

In conclusion, MiRNA-195-5p attenuated SAH-induced vasospasm by up-regulating eNOS, down-regulating iNOS and inhibiting the NF-κ B signaling pathway. It also protected neurons by decreasing SAH-induced apoptosis-related cytokine TNF-α expression in the dentate gyrus. Further study is needed to elucidate the detail mechanism underlying miR-195-5p effect on SAH-induced vasospasm and cerebral injury. We believe that MiR-195-5p can potentially be used to manage SAH-induced cerebral vasospasm and brain injury.

An Insight into the microRNAs Associated with Arteriovenous and Cavernous Malformations of the Brain

Background: Brain arteriovenous malformations (BAVMs) and cerebral cavernous malformations (CCMs) are rare developmental anomalies of the intracranial vasculature, with an irregular tendency to rupture, and as of yet incompletely deciphered pathophysiology. Because of their variety in location, morphology, and size, as well as unpredictable natural history, they represent a management challenge. MicroRNAs (miRNAs) are strands of non-coding RNA of around 20 nucleotides that are able to modulate the expression of target genes by binding completely or partially to their respective complementary sequences. Recent breakthroughs have been made on elucidating their contribution to BAVM and CCM occurrence, growth, and evolution; however, there are still countless gaps in our understanding of the mechanisms involved. Methods: We have searched the Medline (PubMed; PubMed Central) database for pertinent articles on miRNAs and their putative implications in BAVMs and CCMs. To this purpose, we employed various permutations of the terms and idioms: ‘arteriovenous malformation’, ‘AVM’, and ‘BAVM’, or ‘cavernous malformation’, ‘cavernoma’, and ‘cavernous angioma’ on the one hand; and ‘microRNA’, ‘miRNA’, and ‘miR’ on the other. Using cross-reference search; we then investigated additional articles concerning the individual miRNAs identified in other cerebral diseases. Results: Seven miRNAs were discovered to play a role in BAVMs, three of which were downregulated (miR-18a, miR-137, and miR-195*) and four upregulated (miR-7-5p, miR-199a-5p, miR-200b-3p, and let-7b-3p). Similarly, eight miRNAs were identified in CCM in humans and experimental animal models, two being upregulated (miR-27a and mmu-miR-3472a), and six downregulated (miR-125a, miR-361-5p, miR-370-3p, miR-181a-2-3p, miR-95-3p, and let-7b-3p). Conclusions: The following literature review endeavored to address the recent discoveries related to the various implications of miRNAs in the formation and growth of BAVMs and CCMs. Additionally, by presenting other cerebral pathologies correlated with these miRNAs, it aimed to emphasize the potential directions of upcoming research and biological therapies.

Therapeutic Nanoparticles for the Different Phases of Ischemic Stroke

Stroke represents the second leading cause of mortality and morbidity worldwide. Ischemic strokes are the most prevalent type of stroke, and they are characterized by a series of pathological events prompted by an arterial occlusion that leads to a heterogeneous pathophysiological response through different hemodynamic phases, namely the hyperacute, acute, subacute, and chronic phases. Stroke treatment is highly reliant on recanalization therapies, which are limited to only a subset of patients due to their narrow therapeutic window; hence, there is a huge need for new stroke treatments. Nonetheless, the vast majority of promising treatments are not effective in the clinical setting due to their inability to cross the blood-brain barrier and reach the brain. In this context, nanotechnology-based approaches such as nanoparticle drug delivery emerge as the most promising option. In this review, we will discuss the current status of nanotechnology in the setting of stroke, focusing on the diverse available nanoparticle approaches targeted to the different pathological and physiological repair mechanisms involved in each of the stroke phases.

Knockdown of RMST Impedes Neuronal Apoptosis and Oxidative Stress in OGD/R-Induced Ischemic Stroke Via Depending on the miR-377/SEMA3A Signal Network

Long non-coding RNAs (lncRNAs) have pivotal roles in regulating ischemic stroke (IS), including lncRNA rhabdomyosarcoma 2-associated transcript (RMST). The purpose of this report is to discover the functional mechanism of RMST. The expression detection of RMST, microRNA-377 (miR-377) and Semaphorin 3A (SEMA3A) was performed by quantitative real-time polymerase chain reaction (qRT-PCR). Oxygen and glucose deprivation/reperfusion (OGD/R) in N2a cells was used to mimic IS environment in vitro. Cell Counting Kit-8 (CCK-8) and flow cytometry were implemented to assess cell viability and apoptosis. Oxidative stress was analyzed via assaying the associated indicators. Dual-luciferase reporter, RNA pull-down and RNA immunoprecipitation (RIP) assays were jointly administrated for binding analysis between targets. SEMA3A protein level was measured using western blot. We found in IS serum samples, RMST was upregulated while miR-377 was downregulated. After the establishment of OGD/R-induced IS model, we found that the decreased RMST abrogated the OGD/R-triggered apoptosis and oxidative stress. Through the target analysis, miR-377 was shown to be sponged by RMST and the effects of RMST knockdown on OGD/R-induced cell injuries were related to miR-377 upregulation. Besides, SEMA3A served as a target gene of miR-377 and the mitigation of miR-377 for ischemic brain damages was achieved by downregulating SEMA3A. What's more, RMST could regulate SEMA3A by playing the sponge action on miR-377. Collectively, all these findings clarified that RMST repression retarded IS progression in vitro via SEMA3A downregulation by targeting miR-377, which represented a different perspective in the pathological development of IS.

miR-195 and miR-497 in acute stroke and their correlations with post-stroke cognitive impairment

OBJECTIVE

To quantify the expression of miR-195 and miR-497 in acute stroke and to evaluate their correlations with post-stroke cognitive impairment.

METHODS

A total of 108 patients with acute stroke admitted to our hospital from January, 2019 to June, 2020 were enrolled as a patient group, and 76 healthy volunteers were recruited as a normal group. Levels of serum miR-195 and miR-497 in the two groups were quantified. Neurological and cognitive functions were tested by National Institutes of Health Stroke Scale (NIHSS) and Montreal Cognitive Assessment (MoCA), respectively. Diagnostic value of serum miR-195 and miR-497 in acute stroke was evaluated by receiver operating characteristic (ROC) curve, and independent risk factors were determined by multivariate logistic regression.

RESULTS

Levels of serum miR-195 and miR-497 increased in acute stroke. The area under the curve (AUC) of serum miR-195 in the diagnosis of acute stroke was 0.901, while that of serum miR-497 was 0.922. Levels of miR-195 and miR-497 were positively correlated with NIHSS score and negatively correlated with MoCA score. Logistic regression analysis demonstrated that family history of stroke, diabetes, hypertension, NIHSS score, MoCA score, miR-195, and miR-497 were independent risk factors for acute stroke.

CONCLUSION

Serum miR-195 and miR-497 are elevated in acute stroke and associated with the loss of neurologic and cognitive functions. They may be biomarkers for diagnosis and prognosis of acute stroke.

miR-195 reduces age-related blood-brain barrier leakage caused by thrombospondin-1-mediated selective autophagy

Blood–brain barrier (BBB) disruption contributes to neurodegenerative diseases. Loss of tight junction (TJ) proteins in cerebral endothelial cells (ECs) is a leading cause of BBB breakdown. We recently reported that miR‐195 provides vasoprotection, which urges us to explore the role of miR‐195 in BBB integrity. Here, we found cerebral miR‐195 levels decreased with age, and BBB leakage was significantly increased in miR‐195 knockout mice. Furthermore, exosomes from miR‐195‐enriched astrocytes increased endothelial TJ proteins and improved BBB integrity. To decipher how miR‐195 promoted BBB integrity, we first demonstrated that TJ proteins were metabolized via autophagic–lysosomal pathway and the autophagic adaptor p62 was necessary to promote TJ protein degradation in cerebral ECs. Next, proteomic analysis of exosomes revealed miR‐195‐suppressed thrombospondin‐1 (TSP1) as a major contributor to BBB disruption. Moreover, TSP1 was demonstrated to activate selective autophagy of TJ proteins by increasing the formation of claudin‐5‐p62 and ZO1‐p62 complexes in cerebral ECs while TSP1 impaired general autophagy. Delivering TSP1 antibody into the circulation showed dose‐dependent reduction of BBB leakage by 20%–40% in 25‐month‐old mice. Intravenous or intracerebroventricular injection of miR‐195 rescued TSP1‐induced BBB leakage. Dementia patients with BBB damage had higher levels of serum TSP1 compared to those without BBB damage (p = 0.0015), while the normal subjects had the lowest TSP1 (p < 0.0001). Taken together, the study implies that TSP1‐regulated selective autophagy facilitates the degradation of TJ proteins and weakens BBB integrity. An adequate level of miR‐195 can suppress the autophagy–lysosome pathway via a reduction of TSP1, which may be important for maintaining BBB function.

Mesenchymal stem cell-derived extracellular vesicle-based therapies protect against coupled degeneration of the central nervous and vascular systems in stroke

Stem cell-based treatments have been suggested as promising candidates for stroke. Recently, mesenchymal stem cells (MSCs) have been reported as potential therapeutics for a wide range of diseases. In particular, clinical trial studies have suggested MSCs for stroke therapy. The focus of MSC treatments has been directed towards cell replacement. However, recent research has lately highlighted their paracrine actions. The secretion of extracellular vesicles (EVs) is offered to be the main therapeutic mechanism of MSC therapy. However, EV-based treatments may provide a wider therapeutic window compared to tissue plasminogen activator (tPA), the traditional treatment for stroke. Exosomes are nano-sized EVs secreted by most cell types, and can be isolated from conditioned cell media or body fluids such as plasma, urine, and cerebrospinal fluid (CSF). Exosomes apply their effects through targeting their cargos such as microRNAs (miRs), DNAs, messenger RNAs, and proteins at the host cells, which leads to a shift in the behavior of the recipient cells. It has been indicated that exosomes, in particular their functional cargoes, play a significant role in the coupled pathogenesis and recovery of stroke through affecting the neurovascular unit (NVU). Therefore, it seems that exosomes could be utilized as diagnostic and therapeutic tools in stroke treatment. The miRs are small endogenous non-coding RNA molecules which serve as the main functional cargo of exosomes, and apply their effects as epigenetic regulators. These versatile non-coding RNA molecules are involved in various stages of stroke and affect stroke-related factors. Moreover, the involvement of aging-induced changes to specific miRs profile in stroke further highlights the role of miRs. Thus, miRs could be utilized as diagnostic, prognostic, and therapeutic tools in stroke. In this review, we discuss the roles of stem cells, exosomes, and their application in stroke therapy. We also highlight the usage of miRs as a therapeutic choice in stroke therapy.

LncRNA MEG3 Participates in Caerulein-Induced Inflammatory Injury in Human Pancreatic Cells via Regulating miR-195-5p/FGFR2 Axis and Inactivating NF-κB Pathway

Acute pancreatitis (AP) is a dysfunctional pancreas disease marked by severe inflammation. Long non-coding RNAs (lncRNAs) involving in the regulation of inflammatory responses have been frequently mentioned. The purpose of this study was to ensure the function and action mode of lncRNA maternally expressed gene 3 (MEG3) in caerulein-induced AP cell model. HPDE cells were treated with caerulein to establish an AP model in vitro. The expression of MEG3, miR-195-5p, and fibroblast growth factor receptor 2 (FGFR2) was measured using quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation and apoptosis were detected by 3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry assay, respectively. The expression of CyclinD1, B cell lymphoma/leukemia-2 (Bcl-2), Bcl-2-associated X protein (Bax), FGFR2, P65, phosphorylated P65 (p-P65), alpha inhibitor of nuclear factor kappa beta (NF-κB) (IκB-α), and phosphorylated IκB-α (p-IκB-α) at the protein level was quantified by western blot. The concentrations of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) were monitored by enzyme-linked immunosorbent assay (ELISA). The targeted relationship between miR-195-5p and MEG3 or FGFR2 was forecasted by the online software starBase v2.0 and verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. As a result, the expression of MEG3 and FGFR2 was decreased in caerulein-induced HPDE cells, while the expression of miR-195-5p was increased. MEG3 overexpression inhibited cell apoptosis and inflammatory responses that were induced by caerulein. Mechanically, miR-195-5p was targeted by MEG3 and abolished the effects of MEG3 overexpression. FGFR2 was a target of miR-195-5p, and MEG3 regulated the expression of FGFR2 by sponging miR-195-5p. FGFR2 overexpression abolished miR-195-5p enrichment-aggravated inflammatory injuries. Moreover, the NF-κB signaling pathway was involved in the MEG3/miR-195-5p/FGFR2 axis. Collectively, MEG3 participates in caerulein-induced inflammatory injuries by targeting the miR-195-5p/FGFR2 regulatory axis via mediating the NF-κB pathway in HPDE cells.

Epigenetic Mechanisms Underlying Adult Post Stroke Neurogenesis

Stroke remains the leading cause of adult disability. Post-stroke neurogenesis contributes to functional recovery. As an intrinsic neurorestorative process, it is important to elucidate the molecular mechanism underlying stroke-induced neurogenesis and to develop therapies designed specifically to augment neurogenesis. Epigenetic mechanisms include DNA methylation, histone modification and its mediation by microRNAs and long-non-coding RNAs. In this review, we highlight how epigenetic factors including DNA methylation, histone modification, microRNAs and long-non-coding RNAs mediate stroke-induced neurogenesis including neural stem cell self-renewal and cell fate determination. We also summarize therapies targeting these mechanisms in the treatment of stroke.

Long noncoding RNA HULC in acute ischemic stroke: Association with disease risk, severity, and recurrence-free survival and relation with IL-6, ICAM1, miR-9, and miR-195

Background

This study aimed to evaluate the clinical role of long noncoding RNA (lncRNA) HULC in acute ischemic stroke (AIS).

Methods

LncRNA HULC in plasma samples from 215 first episode AIS patients and 215 age/gender‐matched non‐AIS controls was detected by reverse transcriptional‐quantitative polymerase chain reaction (RT‐qPCR). Then, in AIS patients, interleukin‐6 and intercellular adhesion molecule 1 (ICAM1), as well as microRNA (miR) target of lncRNA HUCL (miR‐9 and miR‐195), were detected by enzyme‐linked immunosorbent assay and RT‐qPCR, respectively. Disease severity was assessed by National Institution of Health stroke scale (NIHSS) score. AIS recurrence or death was recorded, and recurrence‐free survival (RFS) was calculated.

Results

LncRNA HULC was increased in AIS patients compared to non‐AIS controls (P < .001), and receiver operating characteristic curve showed that it was correlated with increased AIS risk (area under curve: 0.876, 95% confidence interval: 0.843‐0.908). Meanwhile, lncRNA HULC was positively correlated with NIHSS score (P < .001, r = .456), interleukin‐6 (P < .001, r = .275) and ICAM1 (P < .001, r = .383), whereas negatively correlated with miR‐9 (P < .001, r = −.438) but not miR‐195 (P = .205, r = −.087) in AIS patients. Additionally, miR‐9 was negatively correlated with NIHSS score (P < .001, r = −.335), interleukin‐6 (P = .001, r = −.231), and ICAM1 (P < .001, r = −.280), while miR‐195 was only negatively associated with NIHSS score (P = .041, r = −.139) in AIS patients. Moreover, lncRNA HULC high expression predicted worse RFS (P = .013) in AIS patients.

Conclusion

LncRNA HULC is correlated with higher AIS risk, increased disease severity and worse prognosis in AIS patients. Meanwhile, it associates with higher IL‐6, elevated ICAM1, and lower miR‐9 AIS patients.

MiR-195 alleviates oxygen-glucose deprivation/reperfusion-induced cell apoptosis via inhibition of IKKα-mediated NF-κB pathway

OBJECTIVES

Increasing evidence confirmed that miRNA plays a critical role in the occurrence and development of ischemic stroke. Here, the aim of this study was to examine the function and mechanisms of miR-195 in vascular endothelial cell apoptosis induced by oxygen-glucose deprivation (OGD).

METHODS

This study intended to use OGD to simulate ischemia in vitro. The mRNA expression of miR-195, IKKα and NF-κB in human umbilical vein endothelial cells (HUVECs) were detected by RT-qPCR. The proliferation and apoptosis ability of HUVECs were evaluated using MTT assay, colony formation assay and flow cytometry, respectively. Western blot was applied to examine related protein expression. The interaction between miR-195 and IKKα was verified by dual-luciferase reporter gene assay.

RESULTS

OGD significantly inhibited cell viability and induced cell apoptosis in HUVECs. Meanwhile, OGD treatment notably decreased the expression of miR-195, as well as enhanced NF-κB expression. Moreover, miR-195 directly interacted with IKKα and suppressed its expression. Mechanically, overexpression of miR-195 exhibited pro-proliferation and anti-apoptotic effect on HUVECs treated with OGD through targeting IKKα-mediated NF-κB pathway. At the molecular level, through suppressing IKKα/NF-κB pathway, miR-195 inhibited the expression of pro-apoptotic protein Bax and active caspase-3, but increased the expression of anti-apoptotic Bcl-2 in HUVECs.

CONCLUSIONS

Our finding uncovers the protective effect of miR-195 on the biological behavior of HUVECs via suppression of the NF-κB pathway induced by IKKα, which may provide a new potential strategy for ischemic stroke clinical treatment.

microRNA-195 attenuates neuronal apoptosis in rats with ischemic stroke through inhibiting KLF5-mediated activation of the JNK signaling pathway

BACKGROUND

Accumulating evidence has implicated the regulation of microRNAs (miRs) in ischemia stroke. The current study aimed to elucidate the role of microRNA-195 (miR-195) in neuronal apoptosis and brain plasticity in rats with ischemic stroke via the JNK signaling pathway/KLF5 axis.

METHODS

Ischemic stroke rat models were established by middle cerebral artery occlusion (MCAO), and oxygen deprivation (OGD) models were constructed in rat neuronal cells, followed by gain- or loss-of-function of miR-195 and/or KLF5 in rats and cells. Infarct volume, neuronal loss and ultrastructure, the expression of GAP-43, SYP and KLF5 protein as well as cell apoptosis were determined in the rats. Caspase-3 activity as well as the expression of miR-195, KLF5, GAP-43, SYP, JNK, phosphorylated JNK, Bax and Bcl-2 was measured in the cells.

RESULTS

The infarct size, expression of GAP-43 and SYP protein and apoptotic cells were increased in the miR-195^-/- MCAO rats, while reductions were detected in the miR-195 mimic MCAO and KLF5^-/- MCAO rats. Bcl-2 expression was increased, Bax and Caspase-3 expression as well as the ratio of phosphorylated JNK/JNK was decreased in response to miR-195 overexpression or KLF5 knockdown. Interestingly, the silencing of KLF5 reversed the effects exerted by the miR-195 inhibitor on the expression of Bcl-2, phosphorylated JNK/JNK, Bax and Caspase-3.

CONCLUSIONS

Collectively, our study unraveled that miR-195 could down-regulate KLF5 and block the JNK signaling pathway, ultimately inhibiting neuronal apoptosis in rats with ischemic stroke.

MicroRNA Let-7i Is a Promising Serum Biomarker for Post-stroke Cognitive Impairment and Alleviated OGD-Induced Cell Damage in vitro by Regulating Bcl-2

Background

The mechanism of post-stroke cognitive impairment (PSCI) has not been explained. We aimed to investigate whether miR-let-7i participates in the PSCI and illuminates its underlying role in oxygen–glucose deprivation (OGD)-induced cell apoptosis.

Methods

Blood samples from 36 subjects with PSCI and 38 with post-stroke cognitive normality (Non-PSCI) were collected to evaluate the differential expression of miR-let-7 family members, using qRT-PCT analysis. Spearman correlation was performed to estimate the correlation between the miR-1et-7i level and Montreal Cognitive Assessment (MoCA) score. Treatment of SH-SY5Y cells with OGD was used to induce cell apoptosis in vitro. Effects of miR-let-7i on OGD-induced cell apoptosis was estimated after transfection. The target gene of miR-let-7i was analyzed by dual luciferase reporter gene assay.

Results

The expression of miR-let-7i was up-regulated in PSCI patients compared with Non-PSCI (p < 0.001) and negatively correlated with MoCA score (r = −0.643, p < 0.001). When exposed to OGD, SH-SY5Y cells showed significant apoptosis accompanied by miR-let-7i up-regulation. In OGD-treated cells, miR-let-7i up-regulation was accompanied by cell apoptosis, while down-regulation showed the opposite effect. Luciferase reporter assay showed that Bcl-2 was a target gene of miR-let-7i. Western blot showed that miR-let-7i up-regulation promoted Bcl-2 expression, while qRT-PCR showed that miR-let-7i had no effect on Bcl-2 expression.

Conclusion

miR-let-7i was overexpressed in PSCI patients and it could be used as a diagnostic biomarker for PSCI. We illuminated the potential mechanism that miR-let-7i alleviated OGD-induced cell damage by targeting Bcl-2 at the post-transcriptional level.

LncRNA MEG3 targeting miR-424-5p via MAPK signaling pathway mediates neuronal apoptosis in ischemic stroke

Emerging evidence suggests that long non-coding RNAs (lncRNAs) are significant regulators in the pathological process of ischemic stroke (IS). However, little is known about lncRNAs and their roles in IS. In this study, we aimed to screen out differentially expressed lncRNAs and revealed the underlying mechanisms in IS. The results of bioinformatic analysis showed that lncRNA MEG3 and Sema3A were over-expressed in IS samples, while miR-424-5p was lower-expressed. Correlation between MEG3/miR-424-5p, and miR-424-5p/Sema3A were predicted with miRanda and TargetScan, and verified by dual luciferase assay. Inhibition of MEG3 remarkably increased the expression of miR-424-5p and decreased the expression of Sema3A, which also led to in an increased cell viability and decreased cellular apoptosis in oxygen-glucose deprivation and reoxygenation (OGD/R) model, as well as an activated MAPK signaling pathways. Consistently, MEG3 was upregulated in MCAO mice, knockdown of MEG3 reduced the infarct volume and improved neurobehavioral outcomes in rats following MCAO. In conclusion, it was demonstrated that MEG3 accelerated the process of IS by suppressing miR-424-5p, which targeted Sema3A and the activated MAPK pathway. These results might provide useful information for exploring the potential therapeutic targets in IS.

Nanocarriers for Stroke Therapy: Advances and Obstacles in Translating Animal Studies

The technology of drug delivery systems (DDS) has expanded into many applications, such as for treating neurological disorders. Nanoparticle DDS offer a unique strategy for targeted transport and improved outcomes of therapeutics. Stroke is likely to benefit from the emergence of this technology though clinical breakthroughs are yet to manifest. This review explores the recent advances in this field and provides insight on the trends, prospects and challenges of translating this technology to clinical application. Carriers of diverse material compositions are presented, with special focus on the surface properties and emphasis on the similarities and inconsistencies among in vivo experimental paradigms. Research attention is scattered among various nanoparticle DDS and various routes of drug administration, which expresses the lack of consistency among studies. Analysis of current literature reveals lipid- and polymer-based DDS as forerunners of DDS for stroke; however, cell membrane-derived vesicles (CMVs) possess the competitive edge due to their innate biocompatibility and superior efficacy. Conversely, inorganic and carbon-based DDS offer different functionalities as well as varied capacity for loading but suffer mainly from poor safety and general lack of investigation in this area. This review supports the existing literature by systematizing presently available data and accounting for the differences in drugs of choice, carrier types, animal models, intervention strategies and outcome parameters.

Prediction of miRNA interaction with mRNA of stroke candidate genes

BACKGROUND

The role of miRNA in tissue affected by stroke is actively studied, but it remains unclear which miRNAs and target genes are involved in the development of stroke.

METHODS

The MirTarget program defines the following features of a miRNA binding to a mRNA: the binding start site, the location of the binding site in mRNA, the free energy of a miRNA binding with a mRNA, and the interaction schemes of miRNA and mRNA.

RESULTS

The interaction of 6565 miRNAs with mRNAs of stroke candidate genes was determined. The association of the mRNAs of stroke candidate genes with miRNAs depends on the level of gene expression. Some highly expressed candidate genes are targets of miR-619-5p and miR-5095, which have binding sites located on overlapping mRNA nucleotide sequences (clusters). miR-619-5p and miR-5095 bind to mRNA of 15 genes. Clusters for the binding of miR-1273f,d,e are in mRNAs of highly expressed genes. The start sites of miR-1273d and miR-1273e binding in all clusters are in sequences with one and ten nucleotides, respectively. The clusters of multiple miR-574-5p and ID00470.5p-miR binding sites and the clusters of the miR-466, ID01030.3p-miR, and ID00436.3p-miR binding sites are in mRNAs of some genes expressed at low levels.

CONCLUSION

The organization of miRNA binding sites into clusters reduces the length of mRNA and creates competition between miRNAs for binding to mRNA of a target gene. The characteristics of miRNA associations with target genes can be used to recommend markers for a diagnosis of stroke.

Roles Played by the Na+/Ca2+ Exchanger and Hypothermia in the Prevention of Ischemia-Induced Carrier-Mediated Efflux of Catecholamines into the Extracellular Space: Implications for Stroke Therapy

The release of [³H]dopamine ([³H]DA) and [³H]noradrenaline ([³H]NA) in acutely perfused rat striatal and cortical slice preparations was measured at 37 °C and 17 °C under ischemic conditions. The ischemia was simulated by the removal of oxygen and glucose from the Krebs solution. At 37 °C, resting release rates in response to ischemia were increased; in contrast, at 17 °C, resting release rates were significantly reduced, or resting release was completely prevented. The removal of extracellular Ca²⁺ further increased the release rates of [³H]DA and [³H]NA induced by ischemic conditions. This finding indicated that the Na⁺/Ca²⁺ exchanger (NCX), working in reverse in the absence of extracellular Ca²⁺, fails to trigger the influx of Ca²⁺ in exchange for Na⁺ and fails to counteract ischemia by further increasing the intracellular Na⁺ concentration ([Na⁺]_i). KB-R7943, an inhibitor of NCX, significantly reduced the cytoplasmic resting release rate of catecholamines under ischemic conditions and under conditions where Ca²⁺ was removed. Hypothermia inhibited the excessive release of [³H]DA in response to ischemia, even in the absence of Ca²⁺. These findings further indicate that the NCX plays an important role in maintaining a high [Na⁺]_i, a condition that may lead to the reversal of monoamine transporter functions; this effect consequently leads to the excessive cytoplasmic tonic release of monoamines and the reversal of the NCX. Using HPLC combined with scintillation spectrometry, hypothermia, which enhances the stimulation-evoked release of DA, was found to inhibit the efflux of toxic DA metabolites, such as 3,4-dihydroxyphenylacetaldehyde (DOPAL). In slices prepared from human cortical brain tissue removed during elective neurosurgery, the uptake and release values for [³H]NA did not differ from those measured at 37 °C in slices that were previously maintained under hypoxic conditions at 8 °C for 20 h. This result indicates that hypothermia preserves the functions of the transport and release mechanisms, even under hypoxic conditions. Oxidative stress (H₂O₂), a mediator of ischemic brain injury enhanced the striatal resting release of [³H]DA and its toxic metabolites (DOPAL, quinone). The study supports our earlier findings that during ischemia transmitters are released from the cytoplasm. In addition, the major findings of this study that hypothermia of brain slice preparations prevents the extracellular calcium concentration ([Ca²⁺]_o)-independent non-vesicular transmitter release induced by ischemic insults, inhibiting Na⁺/Cl⁻-dependent membrane transport of monoamines and their toxic metabolites into the extracellular space, where they can exert toxic effects.