MicroRNA-493 regulates angiogenesis in a rat model of ischemic stroke by targeting MIF

miR-6760-5p suppresses neoangiogenesis by targeting Yes-associated protein 1 in patients with moyamoya disease undergoing indirect revascularization

OBJECTIVE

The aim of this research was to investigate the specific regulatory role of miR-6760-5p in angiogenesis in moyamoya disease.

METHODS

HUVECs were transfected with miR-6760-5p inhibitor and mimics fragments, then subjected to assays for cell proliferation, migration, and tube formation. Subsequently, downstream target genes of miR-6760-5p were predicted and the protein expression levels of these genes were evaluated. The presence of miR-6760-5p and YAP1 was verified by a dual luciferase reporter gene test, followed by an assessment of the effects of YAP1 and miR-6760-5p on the HUVECs.

RESULTS

Comparatively to the control group, increased expression of miR-6760-5p decreased cell growth, movement, and tube formation. YAP1 gene was discovered as a target controlled by miR-6760-5p, with subsequent investigation confirming YAP1 as a gene regulated by miR-6760-5p. Additionally, miR-6760-5p was found to counteract the angiogenesis-promoting effect of YAP1.

CONCLUSION

The results of this research suggest a possible link between the miR-6760-5p gene found in the cerebrospinal fluid of individuals with moyamoya disease and the process of vascularization in this particular condition. The findings indicate that miR-6760-5p may be a new molecular indicator and potential target for the diagnosis of moyamoya disease.

MicroRNA-451 Regulates Angiogenesis in Intracerebral Hemorrhage by Targeting Macrophage Migration Inhibitory Factor

Intracerebral hemorrhage (ICH) is a subtype of stroke with the highest fatality and disability rate. Up to now, commonly used first-line therapies have limited value in improving prognosis. Angiogenesis is essential to neurological recovery after ICH. Recent studies have shown that microRNA-451(miR-451) plays an important role in angiogenesis by regulating the function of vascular endothelial cells. We found miR-451 was significantly decreased in the peripheral blood of ICH patients in the acute stage. Based on the clinical findings, we conducted this study to investigate the potential regulatory effect of miR-451 on angiogenesis after ICH. The expression of miR-451 in ICH mouse model and in a hemin toxicity model of human brain microvascular endothelial cells (hBMECs) was decreased the same as in ICH patients. MiR-451 negatively regulated the proliferation, migration, and tube formation of hBMECs in vitro. MiR-451 negatively regulated the microvessel density in the perihematoma tissue and affected neural functional recovery of ICH mouse model. Knockdown of miR-451 could recovered tight junction and protect the integrity of blood-brain barrier after ICH. Based on bioinformatic programs, macrophage migration inhibitory factor (MIF) was predicted to be the target gene and identified to be regulated by miR-451 inhibiting the protein translation. And p-AKT and p-ERK were verified to be downstream of MIF in angiogenesis. These results all suggest that miR-451 will be a potential target for regulating angiogenesis in ICH.

Non-coding RNAs and angiogenesis in cardiovascular diseases: a comprehensive review

Non-coding RNAs (ncRNAs) have key roles in the etiology of many illnesses, including heart failure, myocardial infarction, stroke, and in physiological processes like angiogenesis. In transcriptional regulatory circuits that control heart growth, signaling, and stress response, as well as remodeling in cardiac disease, ncRNAs have become important players. Studies on ncRNAs and cardiovascular disease have made great progress recently. Here, we go through the functions of non-coding RNAs (ncRNAs) like circular RNAs (circRNAs), and microRNAs (miRNAs) as well as long non-coding RNAs (lncRNAs) in modulating cardiovascular disorders.

Blood-derived microRNAs are related to cognitive domains in the general population

INTRODUCTION

Blood-derived microRNAs (miRNAs) are potential candidates for detecting and preventing subclinical cognitive dysfunction. However, replication of previous findings and identification of novel miRNAs associated with cognitive domains, including their relation to brain structure and the pathways they regulate, are still lacking.

METHODS

We examined blood-derived miRNAs and miRNA co-expression clusters in relation to cognitive domains, structural magnetic resonance imaging measures, target gene expression, and genetic variants in 2869 participants of a population-based cohort.

RESULTS

Five previously identified and 14 novel miRNAs were associated with cognitive domains. Eleven of these were also associated with cortical thickness and two with hippocampal volume. Multi-omics analysis showed that certain identified miRNAs were genetically influenced and regulated genes in pathways like neurogenesis and synapse assembly.

DISCUSSION

We identified miRNAs associated with cognitive domains, brain regions, and neuronal processes affected by aging and neurodegeneration, making them promising candidate blood-based biomarkers or therapeutic targets of subclinical cognitive dysfunction.

HIGHLIGHTS

We investigated the association of blood-derived microRNAs with cognitive domains. Five previously identified and 14 novel microRNAs were associated with cognition. Eleven cognition-related microRNAs were also associated with cortical thickness. Identified microRNAs were linked to genes associated with neuronal functions. Results provide putative biomarkers or therapeutic targets of cognitive aging.

Macrophage migration inhibitor factor (MIF): Potential role in cognitive impairment disorders

Macrophage migration inhibitory factor (MIF) is a cytokine in the immune system, participated in both innate and adaptive immune responses. Except from immune cells, MIF is also secreted by a variety of non-immune cells, including hematopoietic cells, endothelial cells (ECs), and neurons. MIF plays a crucial role in various diseases, such as sepsis, rheumatoid arthritis, acute kidney injury, and neurodegenerative diseases. The role of MIF in the neuropathogenesis of cognitive impairment disorders is emphasized, as it recruits multiple inflammatory mediators, leading to activating microglia or astrocyte-derived neuroinflammation. Furthermore, it contributes to the cell death of neurons and ECs with the binding of apoptosis-inducing factor (AIF) through parthanatos-associated apoptosis-inducing factor nuclease (PAAN) / MIF pathway. This review comprehensively delves into the relationship between MIF and the neuropathogenesis of cognitive impairment disorders, providing a series of emerging MIF-targeted pharmaceuticals as potential treatments for cognitive impairment disorders.

CircRNA_102046 Affects the Occurrence and Development of Ischemic Stroke by Regulating the miR-493-5p/ROCK1 Signaling

In our previous studies, the results have revealed that circRNA_102046 is significantly upregulated in plasma of patients with ischemic stroke, which closely related to NIHSS score. Human neural stem cells (hNSCs) were used for characterization and subcellular localization of circRNA_102046, and hNSCs OGD/R model was generated. The proliferation of cells was examined by CCK-8 assay. The expression levels of associated molecules were evaluated using RT-qPCR, immunofluorescence staining or western blotting. The binding and co-localization of associated molecules were also evaluated by RIP and FISH assay. Furthermore, MCAO mouse model was established to examine the effects of circRNA_102046 on the progression of ischemic stroke. Expression of circRNA_102046 was detected in the cytoplasma of hNSCs. Then OGD/R cell model was established, where the levels of circRNA_102046 was significantly up-regulated. Furthermore, knockdown of circRNA_102046 was able to enhance the proliferation and differentiation of OGD/R hNSCs. In further downstream molecular studies, the results indicated that circRNA_102046 could participate in the occurrence and development of ischemic stroke through targeting miR-493-5p. In addition, ROCK1 was identified as the putative target of miR-493-5p, and circRNA_102046 regulates the proliferation and differentiation of hNSCs via the miR-493-5p/ROCK1 signaling. More importantly, the infarct volumes of MCAO mice were remarkably reduced after the treatment with sh-circRNA_102046, which also up- and down-regulate the expression of miR-493-5p and ROCK1, respectively. Elucidating this novel pathway provides a theoretical basis for the development of new diagnostic approach and targeted treatment for ischemic stroke.

MicroRNA Profiles in Critically Ill Patients

The use of biomarkers to expedite diagnosis, prognostication, and treatment could significantly improve patient outcomes. The early diagnosis and treatment of critical illnesses can greatly reduce mortality and morbidity. Therefore, there is great interest in the discovery of biomarkers for critical illnesses. Micro-ribonucleic acids (miRNAs) are a highly conserved group of non-coding RNA molecules. They regulate the expression of genes involved in several developmental, physiological, and pathological processes. The characteristics of miRNAs suggest that they could be versatile biomarkers. Assay panels to measure the expression of several miRNAs could facilitate clinical decision-- making for a range of diseases. We have, in this paper, reviewed the current understanding of the role of miRNAs as biomarkers in critically ill patients.

CircRIMS promotes cerebral ischemia-reperfusion injury through increasing apoptosis and targeting the miR-96-5p/JAK/STAT1 axis

OBJECTIVE

This study aims to explore the function of circRIMS in cerebral ischemia/reperfusion (CIR) and its regulatory mechanism.

METHOD

The expression of the circRIMS was examined in GEO chip data and validated by qRT-PCR analysis. A middle cerebral artery occlusion/repression (MCAO/R) model was developed using C57BL/6J mice. Starbase and circinteractome were employed to identify the target miRNA and mRNA. The result was confirmed by dual-luciferase reporter assay, and biotinylated RNA-pulldown assay. The cell viability and apoptosis were confirmed through CCK-8 and flow cytometry assay.

RESULTS

This study revealed that circRIMS expression was upregulated in MCAO mice model and OGD/RX-simulated cell model. Knockdown circRIMS demonstrated the functional of circRIMS in increasing cell viability, reducing apoptosis, LDH activity and inflammatory factors secretion in OGD/RX-simulated CIR injury in vitro. Additionally, miR-96-5p was identified as a target of circRIMS, while the STAT1 gene is a downstream gene of miR-96-5p, and JAK was also considered to be a downstream gene of the JAK-STAT pathway. Furthermore, inhibition of miR-96-5p or overexpression of STAT1 promoted the progression of CIR injury by elevating apoptosis, reducing cell viability, and increasing the secretion of inflammatory cytokines.

CONCLUSION

CircRIMS contributes to the progression of CIR injury via regulating miR-96-5p/JAK/STAT1 axis.

Angiogenesis after ischemic stroke

Owing to its high disability and mortality rates, stroke has been the second leading cause of death worldwide. Since the pathological mechanisms of stroke are not fully understood, there are few clinical treatment strategies available with an exception of tissue plasminogen activator (tPA), the only FDA-approved drug for the treatment of ischemic stroke. Angiogenesis is an important protective mechanism that promotes neural regeneration and functional recovery during the pathophysiological process of stroke. Thus, inducing angiogenesis in the peri-infarct area could effectively improve hemodynamics, and promote vascular remodeling and recovery of neurovascular function after ischemic stroke. In this review, we summarize the cellular and molecular mechanisms affecting angiogenesis after cerebral ischemia registered in PubMed, and provide pro-angiogenic strategies for exploring the treatment of ischemic stroke, including endothelial progenitor cells, mesenchymal stem cells, growth factors, cytokines, non-coding RNAs, etc.

CircPDS5B Reduction Improves Angiogenesis Following Ischemic Stroke by Regulating MicroRNA-223-3p/NOTCH2 Axis

Background and Objectives

Ischemic stroke (IS) is responsible for major causes of global death and disability, for which promoting angiogenesis is a promising therapeutic strategy. This study analyzed circular RNA PDS5B (circPDS5B) and its related mechanisms in angiogenesis in IS.

Methods

In the permanent middle cerebral artery occlusion (pMCAO) mouse model, circPDS5B, microRNA (miR)-223-3p, and NOTCH2 levels were checked. By testing neurologic function, neuronal apoptosis, and expression of angiogenesis-related proteins in pMCAO mice, the protective effects of circPDS5B knockdown were probed. In human brain microvascular endothelial cells (HBMECs) under oxygen-glucose deprivation (OGD) conditions, the effects of circPDS5B, miR-223-3p, and NOTCH2 on angiogenesis were studied by measuring cellular activities.

Results

The increase of circPDS5B and NOTCH2 expression and the decrease of miR-223-3p expression were examined in pMCAO mice. Reducing circPDS5B expression indicated protection against neurologic dysfunction, apoptosis, and angiogenesis impairment. For circPDS5B-depleted or miR-223-3p-restored HBMECs under OGD treatment, angiogenesis was promoted. MiR-223-3p inhibition-associated reduction of angiogenesis could be counteracted by knocking down NOTCH2. CircPDS5B depletion-induced angiogenesis in OGD-conditioned HBMECs was repressed after overexpressing NOTCH2.

Discussion

In IS, the expression of circPDS5B was upregulated, and miR-223-3p inhibited HBMECs activity and promoted NOTCH2 expression, thus promoting IS. CircPDS5B reduction improves angiogenesis following ischemic stroke by regulating microRNA-223-3p/NOTCH2 axis.

Dualistic roles and mechanistic insights of macrophage migration inhibitory factor in brain injury and neurodegenerative diseases

Macrophage migration inhibitory factor (MIF) is involved in various immune-mediated pathologies and regulates both innate and adaptive immune reactions, thus being related to several acute and chronic inflammatory diseases such as rheumatoid arthritis, septic shock, and atherosclerosis. Its role in acute and chronic brain pathologies, such as stroke and neurodegenerative diseases, has attracted increasing attention in recent years. In response to stimuli like hypoxia, inflammation or infection, different cell types can rapidly release MIF, including immune cells, endothelial cells, and neuron cells. Notably, clinical data from past decades also suggested a possible link between serum MIF levels and the severity of stroke and the evolving of neurodegenerative diseases. In this review, we summarize the major and recent findings focusing on the mechanisms of MIF modulating functions in brain injury and neurodegenerative diseases, which may provide important therapeutic targets meriting further investigation.

microRNA as a therapeutic for ischemic stroke

microRNA (miRNA) are important regulators of gene expression. miRNA have the potential as a treatment to modulate genes, pathways and cells involved in ischemic stroke. In this review, we specifically present miRNA in stroke as a treatment to decrease thrombosis, reduce blood brain barrier (BBB) disruption and hemorrhagic transformation (HT), modulate inflammation, and modify angiogenesis. miRNA as a treatment for stroke is an emerging area with evidence from animal studies demonstrating its potential. While no miRNA is currently approved for human use, several have shown promise in clinical trials to treat medical conditions, such as miR-122 for hepatitis C. The role of miRNA as a treatment for specific applications in ischemic stroke is presented including a discussion of the benefits and barriers of miRNA as a treatment, and directions for future advancement.

Predicting Microenvironment in CXCR4- and FAP-Positive Solid Tumors-A Pan-Cancer Machine Learning Workflow for Theranostic Target Structures

(1) Background: C-X-C Motif Chemokine Receptor 4 (CXCR4) and Fibroblast Activation Protein Alpha (FAP) are promising theranostic targets. However, it is unclear whether CXCR4 and FAP positivity mark distinct microenvironments, especially in solid tumors. (2) Methods: Using Random Forest (RF) analysis, we searched for entity-independent mRNA and microRNA signatures related to CXCR4 and FAP overexpression in our pan-cancer cohort from The Cancer Genome Atlas (TCGA) database-representing n = 9242 specimens from 29 tumor entities. CXCR4- and FAP-positive samples were assessed via StringDB cluster analysis, EnrichR, Metascape, and Gene Set Enrichment Analysis (GSEA). Findings were validated via correlation analyses in n = 1541 tumor samples. TIMER2.0 analyzed the association of CXCR4 / FAP expression and infiltration levels of immune-related cells. (3) Results: We identified entity-independent CXCR4 and FAP gene signatures representative for the majority of solid cancers. While CXCR4 positivity marked an immune-related microenvironment, FAP overexpression highlighted an angiogenesis-associated niche. TIMER2.0 analysis confirmed characteristic infiltration levels of CD8+ cells for CXCR4-positive tumors and endothelial cells for FAP-positive tumors. (4) Conclusions: CXCR4- and FAP-directed PET imaging could provide a non-invasive decision aid for entity-agnostic treatment of microenvironment in solid malignancies. Moreover, this machine learning workflow can easily be transferred towards other theranostic targets.

Systematic Analysis of CXC Chemokine-Vascular Endothelial Growth Factor A Network in Colonic Adenocarcinoma from the Perspective of Angiogenesis

Background

Tumor angiogenesis plays a vital role in tumorigenesis, proliferation, and metastasis. Recently, vascular endothelial growth factor A (VEGFA) and CXC chemokines have been shown to play vital roles in angiogenesis. Exploring the expression level, gene regulatory network, prognostic value, and target prediction of the CXC chemokine-VEGFA network in colon adenocarcinoma (COAD) is crucial from the perspective of tumor angiogenesis.

Methods

In this study, we analyzed gene expression and regulation, prognostic value, target prediction, and immune infiltrates related to the CXC chemokine-VEGFA network in patients with COAD using multiple databases (cBioPortal, UALCAN, Human Protein Atlas, GeneMANIA, GEPIA, TIMER (version 2.0), TRRUST (version 2), LinkedOmics, and Metascape).

Results

Our results showed that CXCL1/2/3/5/6/8/11/16/17 and VEGFA were markedly overexpressed, while CXCL12/13/14 were underexpressed in patients with COAD. Moreover, genetic alterations in the CXC chemokine-VEGFA network found at varying rates in patients with COAD were as follows: CXCL1/2/17 (2.1%), CXCL3/16 (2.6%), CXCL5/14 (2.4%), CXCL6 (3%), CXCL8 (0.8%), CXCL11/13 (1.9%), CXCL12 (0.6%), and VEGFA (1.3%). Promoter methylation of CXCL1/2/3/11/13/17 was considerably lower in patients with COAD, whereas methylation of CXCL5/6/12/14 and VEGFA was considerably higher. Furthermore, CXCL9/10/11 and VEGFA expression was notably correlated with the pathological stages of COAD. In addition, patients with COAD with high CXCL8/11/14 or low VEGFA expression levels survived longer than patients with dissimilar expression levels. CXC chemokines and VEGFA form a complex regulatory network through coexpression, colocalization, and genetic interactions. Moreover, many transcription factor targets of the CXC chemokine-VEGFA network in patients with COAD were identified: RELA, NFKB1, ZFP36, XBP1, HDAC2, SP1, ATF4, EP300, BRCA1, ESR1, HIF1A, EGR1, STAT3, and JUN. We further identified the top three miRNAs involved in regulating each CXC chemokine within the network: miR-518C, miR-369-3P, and miR-448 regulated CXCL1; miR-518C, miR-218, and miR-493 regulated CXCL2; miR-448, miR-369-3P, and miR-221 regulated CXCL3; miR-423 regulated CXCL13; miR-378, miR-381, and miR-210 regulated CXCL14; miR-369-3P, miR-382, and miR-208 regulated CXCL17; miR-486 and miR-199A regulated VEGFA. Furthermore, the CXC chemokine-VEGFA network in patients with COAD was notably associated with immune infiltration.

Conclusions

This study revealed that the CXC chemokine-VEGFA network might act as a prognostic biomarker for patients with COAD. Moreover, our study provides new therapeutic targets for COAD, serving as a reference for further research in the future.

Polygenic Risk Score Improves Cataract Prediction in East Asian Population

Cataracts, characterized by crystalline lens opacities in human eyes, is the leading cause of blindness globally. Due to its multifactorial complexity, the molecular mechanisms remain poorly understood. Larger cohorts of genome-wide association studies (GWAS) are needed to investigate cataracts’ genetic basis. In this study, a GWAS was performed on the largest Han population to date, analyzing a total of 7079 patients and 13,256 controls from the Taiwan Biobank (TWB) 2.0 cohort. Two cataract-associated SNPs with an adjustment of p < 1 × 10−7 in the older groups and nine SNPs with an adjustment of p < 1 × 10−6 in the younger group were identified. Except for the reported AGMO in animal models, most variations, including rs74774546 in GJA1 and rs237885 in OXTR, were not identified before this study. Furthermore, a polygenic risk score (PRS) was created for the young and old populations to identify high-risk cataract individuals, with areas under the receiver operating curve (AUROCs) of 0.829 and 0.785, respectively, after covariate adjustments. Younger individuals had 17.45 times the risk while older people had 10.97 times the risk when comparing individuals in the highest and lowest PRS quantiles. Validation analysis on an independent TWB1.0 cohort revealed AUROCs of 0.744 and 0.659.

Neuroprotective Effect of Macrophage Migration Inhibitory Factor (MIF) in a Mouse Model of Ischemic Stroke

The mechanism of the neuroprotective effect of the macrophage migration inhibitory factor (MIF) in vivo is unclear. We investigated whether the MIF promotes neurological recovery in an in vivo mouse model of ischemic stroke. Transient middle cerebral artery occlusion (MCAO) surgery was performed to make ischemic stroke mouse model. Male mice were allocated to a sham vehicle, a sham MIF, a middle cerebral artery occlusion (MCAO) vehicle, and MCAO+MIF groups. Transient MCAO (tMCAO) was performed in the MCAO groups, and the vehicle and the MIF were administered via the intracerebroventricular route. We evaluated the neurological functional scale, the rotarod test, and T2-weighted magnetic resonance imaging. The expression level of the microtubule-associated protein 2 (MAP2), Bcl2, and the brain-derived neurotrophic factor (BDNF) were further measured by Western blot assay. The Garcia test was significantly higher in the MCAO+MIF group than in the MCAO+vehicle group. The MCAO+MIF group exhibited significantly better performance on the rotarod test than the MCAO+vehicle group, which further had a significantly reduced total infarct volume on T2-weighted MRI imaging than the MCAO vehicle group. Expression levels of BDNF, and MAP2 tended to be higher in the MCAO+MIF group than in the MCAO+vehicle group. The MIF exerts a neuroprotective effect in an in vivo ischemic stroke model. The MIF facilitates neurological recovery and protects brain tissue from ischemic injury, indicating a possibility of future novel therapeutic agents for stroke patients.

Noncoding RNA as Diagnostic and Prognostic Biomarkers in Cerebrovascular Disease

Noncoding RNAs (ncRNAs), such as microRNAs, long noncoding RNAs, and circular RNAs, play an important role in the pathophysiology of cerebrovascular diseases (CVDs). They are effectively detectable in body fluids, potentially suggesting new biomarkers for the early detection and prognosis of CVDs. In this review, the physiological functions of circulating ncRNAs and their potential role as diagnostic and prognostic markers in patients with cerebrovascular diseases are discussed, especially in acute ischemic stroke, subarachnoid hemorrhage, and moyamoya disease.

Circulating Exosomal miRNAs as Novel Biomarkers Perform Superior Diagnostic Efficiency Compared With Plasma miRNAs for Large-Artery Atherosclerosis Stroke

Recently, exosomal miRNAs have been reported to be associated with some diseases, and these miRNAs can be used for diagnosis and treatment. However, diagnostic biomarkers of exosomal miRNAs for ischemic stroke have rarely been studied. In the present study, we aimed to identify exosomal miRNAs that are associated with large-artery atherosclerosis (LAA) stroke, the most common subtype of ischemic stroke; to further verify their diagnostic efficiency; and to obtain promising biomarkers. High-throughput sequencing was performed on samples from 10 subjects. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed on exosomes and plasma in the discovery phase (66 subjects in total) and the validation phase (520 subjects in total). We identified 5 candidate differentially expressed miRNAs (miR-369-3p, miR-493-3p, miR-379-5p, miR-1296-5p, and miR-1277-5p) in the discovery phase according to their biological functions, 4 of which (miR-369-3p, miR-493-3p, miR-379-5p, and miR-1296-5p) were confirmed in the validation phase. These four exosomal miRNAs could be used to distinguish LAA samples from small artery occlusion (SAO) samples, LAA samples from atherosclerosis (AS) samples, and LAA samples from control samples and were superior to plasma miRNAs. In addition, composite biomarkers achieved higher area under the curve (AUC) values than single biomarkers. According to our analysis, the expression levels of exosomal miR-493-3p and miR-1296-5p were negatively correlated with the National Institutes of Health Stroke Scale (NIHSS) score. The four identified exosomal miRNAs are promising biomarkers for the diagnosis of LAA stroke, and their diagnostic efficiency is superior to that of their counterparts in plasma.

Genetic deletion of endothelial microRNA-15a/16-1 promotes cerebral angiogenesis and neurological recovery in ischemic stroke through Src signaling pathway

Cerebral angiogenesis is tightly controlled by specific microRNAs (miRs), including the miR-15a/16-1 cluster. Recently, we reported that endothelium-specific conditional knockout of the miR-15a/16-1 cluster (EC-miR-15a/16-1 cKO) promotes post-stroke angiogenesis and improves long-term neurological recovery by increasing protein levels of VEGFA, FGF2, and their respective receptors VEGFR2 and FGFR1. Herein, we further investigated the underlying signaling mechanism of these pro-angiogenic factors after ischemic stroke using a selective Src family inhibitor AZD0530. EC-miR-15a/16-1 cKO and age- and sex-matched wild-type littermate (WT) mice were subjected to 1 h middle cerebral artery occlusion (MCAO) and 28d reperfusion. AZD0530 was administered daily by oral gavage to both genotypes of mice 3-21d after MCAO. Compared to WT, AZD0530 administration exacerbated spatial cognitive impairments and brain atrophy in EC-miR-15a/16-1 cKO mice following MCAO. AZD0530 also attenuated long-term recovery of blood flow and inhibited the formation of new microvessels, including functional vessels with blood circulation, in the penumbra of stroked cKO mice. Moreover, AZD0530 blocked the Src signaling pathway by downregulating phospho-Src and its downstream mediators (p-Stat3, p-Akt, p-FAK, p-p44/42 MAPK, p-p38 MAPK) in post-ischemic brains. Collectively, our data demonstrated that endothelium-targeted deletion of the miR-15a/16-1 cluster promotes post-stroke angiogenesis and improves long-term neurological recovery via activating Src signaling pathway.

MiRNA: Involvement of the MAPK Pathway in Ischemic Stroke. A Promising Therapeutic Target

Ischemic stroke (IS) is a cerebrovascular disease with a high rate of disability and mortality. It is classified as the second leading cause of death that arises from the sudden occlusion of small vessels in the brain with consequent lack of oxygen and nutrients in the brain tissue. Following an acute ischemic event, the cascade of events promotes the activation of multiple signaling pathways responsible for irreversible neuronal damage. The mitogen-activated protein kinase (MAPK) signaling pathway transmits signals from the cell membrane to the nucleus in response to different stimuli, regulating proliferation, differentiation, inflammation, and apoptosis. Several lines of evidence showed that MAPK is an important regulator of ischemic and hemorrhagic cerebral vascular disease; indeed, it can impair blood–brain barrier (BBB) integrity and exacerbate neuroinflammation through the release of pro-inflammatory mediators implementing neurovascular damage after ischemic stroke. This review aims to illustrate the miRNAs involved in the regulation of MAPK in IS, in order to highlight possible targets for potential neuroprotective treatments. We also discuss some miRNAs (miR), including miR-145, miR-137, miR-493, and miR-126, that are important as they modulate processes such as apoptosis, neuroinflammation, neurogenesis, and angiogenesis through the regulation of the MAPK pathway in cerebral IS. To date, limited drug therapies are available for the treatment of IS; therefore, it is necessary to implement preclinical and clinical studies aimed at discovering novel therapeutic approaches to minimize post-stroke neurological damage.

LncRNA MEG3 inhibits the proliferation of neural stem cells after ischemic stroke via the miR-493-5P/MIF axis

OBJECTIVE

The proliferation of neural stem cells (NSCs1), or lack thereof, can have profound effects on brain tissue remodeling for ischemic stroke (IS2). In this study, we aimed to reveal the influence of the lncRNA MEG3/miR-493-5p/MIF axis on NSC proliferation after IS.

METHODS

We established an oxygen glucose-deprivation/reoxygenation (OGD/R3) in vitro model of IS in NSCs. We evaluated NSC isolation efficiency and proliferation by NESTIN, SOX2, and PCNA immunofluorescence staining. MEG3 and miR-493-5P levels were assessed by quantitative real-time polymerase chain reaction (qRT-PCR4). Changes in MIF protein expression levels were analyzed using Western blotting. We then evaluated the role of MEG3 and miR-493-5p by transfection of si-MEG3, a miR-493-5p mimic, or miR-493-5p inhibitor. NSC proliferation was quantified using Cell Counting Kit-8 analysis.

RESULTS

NESTIN and SOX2 were co-expressed in endogenous NSCs. Following OGD/R, MEG3 and miR-493-5P were significantly upregulated in NSCs, while MIF levels decreased and proliferation was inhibited. Knockdown of MEG3 inhibited miR-493-5p and rescued expression of MIF and PCNA, restoring cellular proliferation levels. In NSCs transfected with a miR-493-5p mimic or inhibitor, MIF levels were down- or upregulated, respectively. Consistently, transfection of a miR-493-5p mimic reduced NSC proliferation, while transfection with a miR-493-5p inhibitor or si-MEG3 rescued the inhibitory effect of OGD/R on NSC proliferation. After co-transfection of si-MEG3 and a miR-493-5p mimic of OGD/R-induced NSCs, levels of PCNA, an indicator of cellular proliferation, were significantly reduced. Conclusion MEG3 inhibits NSC proliferation of after IS via positive regulation of miR-493-5p and potential subsequent downregulation of MIF.

Effective silencing of miR-126 after ischemic stroke by means of intravenous α-tocopherol-conjugated heteroduplex oligonucleotide in mice

Brain endothelial cells (BECs) are involved in the pathogenesis of ischemic stroke. Recently, several microRNAs (miRNAs) in BECs were reported to regulate the endothelial function in ischemic brain. Therefore, modulation of miRNAs in BECs by a therapeutic oligonucleotide to inhibit miRNA (antimiR) could be a useful strategy for treating ischemic stroke. However, few attempts have been made to achieve this strategy via systemic route due to lack of efficient delivery-method toward BECs. Here, we have developed a new technology for delivering an antimiR into BECs and silencing miRNAs in BECs, using a mouse ischemic stroke model. We designed a heteroduplex oligonucleotide, comprising an antimiR against miRNA-126 (miR-126) known as the endothelial-specific miRNA and its complementary RNA, conjugated to α-tocopherol as a delivery ligand (Toc-HDO targeting miR-126). Intravenous administration of Toc-HDO targeting miR-126 remarkably suppressed miR-126 expression in ischemic brain of the model mice. In addition, we showed that Toc-HDO targeting miR-126 was delivered into BECs more efficiently than the parent antimiR in ischemic brain, and that it was delivered more effectively in ischemic brain than non-ischemic brain of this model mice. Our study highlights the potential of this technology as a new clinical therapeutic option for ischemic stroke.

Endothelial Progenitor Cell-Derived Microvesicles Promote Angiogenesis in Rat Brain Microvascular Endothelial Cells In vitro

Brain microvascular endothelial cells (BMECs) are a major component of the blood-brain barrier that maintains brain homeostasis. Preserving and restoring the normal biological functions of BMECs can reverse or reduce brain injury. Endothelial progenitor cells (EPCs) may promote brain vascular remodeling and restore normal endothelial function. As a novel vehicle for cell-cell communication, microvesicles (MVs) have varied biological functions. The present study investigated the biological effects of EPC-derived MVs (EPC-MVs) on BMECs in vitro. We isolated MVs from the supernatant of EPCs in a serum-depleted medium. BMECs were cultured alone or in the presence of EPC-MVs. BMEC viability and proliferation were evaluated with the Cell Counting Kit-8 and by flow cytometry, and the proangiogenic effect of EPC-MVs on BMECs was assessed with the transwell migration, wound healing, and tube formation assays. Our results showed that EPC-derived MVs labeled with DiI were internalized by cultured BMECs; this enhanced BMEC viability and promoted their proliferation. EPC-MVs also stimulated migration and tube formation in BMECs. These results demonstrate that EPC-derived MVs exert a proangiogenic effect on BMECs, which has potential applications in cell-free therapy for brain injury.

The role of exosomal microRNAs in central nervous system diseases

MicroRNAs (miRNA), endogenous non-coding RNAs approximately 22 nucleotides long, regulate gene expression by mediating translational inhibition or mRNA degradation. Exosomes are a tool for intercellular transmission of information in which miRNA exchange plays an important role. Under pathophysiological conditions in the central nervous system (CNS), cellular transmission of exosomal miRNAs can regulate signaling pathways. Exosomal miRNAs are involved in the occurrence and development of diverse CNS diseases, such as traumatic brain injury, spinal cord injury, stroke, neurodegenerative diseases, epilepsy, and glioma. The use of exosomes as transport vehicles for certain miRNAs provides a novel therapeutic strategy for CNS diseases. Furthermore, the exosomes in body fluids change with the occurrence of diseases, indicating that subtle changes in physiological and pathological processes in vivo could be recognized by analyzing exosomes. Exosomal analysis is expected to act as a novel tool for diagnosis and prediction of neurological diseases. In this review, we present the current understanding of the implications of miRNAs in CNS diseases and summarize the role and mechanism of action of exosomal miRNA in nervous system disease models.

The Role of Angiogenesis-Inducing microRNAs in Vascular Tissue Engineering

Angiogenesis is an important process in tissue repair and regeneration as blood vessels are integral to supply nutrients to a functioning tissue. In this review, the application of microRNAs (miRNAs) or anti-miRNAs that can induce angiogenesis to aid in blood vessel formation for vascular tissue engineering in ischemic diseases such as peripheral arterial disease and stroke, cardiac diseases, and skin and bone tissue engineering is discussed. Endothelial cells (ECs) form the endothelium of the blood vessel and are recognized as the primary cell type that drives angiogenesis and studied in the applications that were reviewed. Besides ECs, mesenchymal stem cells can also play a pivotal role in these applications, specifically, by secreting growth factors or cytokines for paracrine signaling and/or as constituent cells in the new blood vessel formed. In addition to delivering miRNAs or cells transfected/transduced with miRNAs for angiogenesis and vascular tissue engineering, the utilization of extracellular vesicles (EVs), such as exosomes, microvesicles, and EVs collectively, has been more recently explored. Proangiogenic miRNAs and anti-miRNAs contribute to angiogenesis by targeting the 3'-untranslated region of targets to upregulate proangiogenic factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor, and hypoxia-inducible factor-1 and increase the transduction of VEGF signaling through the PI3K/AKT and Ras/Raf/MEK/ERK signaling pathways such as phosphatase and tensin homolog or regulating the signaling of other pathways important for angiogenesis such as the Notch signaling pathway and the pathway to produce nitric oxide. In conclusion, angiogenesis-inducing miRNAs and anti-miRNAs are promising tools for vascular tissue engineering for several applications; however, future work should emphasize optimizing the delivery and usage of these therapies as miRNAs can also be associated with the negative implications of cancer.

miRNA dysregulation in ischaemic stroke: Focus on diagnosis, prognosis, therapeutic and protective biomarkers

Stroke is one of the leading causes of death and disability in both developing and developed countries. Biomarkers for stroke and its outcome can greatly facilitate early detection and management of the disease. miRNAs have been explored for their potential as biomarkers for diagnosis, prognosis and brain injury in ischaemic stroke. A substantial body of evidence suggests that miRNAs play key roles in numerous cellular changes following ischaemic stroke including mitochondrial dysfunction, energy failure, cytokine-mediated cytotoxicity, oxidative stress, activation of glial cells, increased intracellular calcium levels inflammatory responses and disruption of the blood-brain barrier (BBB). In addition, targeting specific miRNAs, therapeutic modulation of brain injury and apoptosis can also be achieved. Therefore, the current review has been compiled within an aim to give an overview of the developments exploiting miRNAs at different stages of stroke as prognostic, diagnostic, protective and therapeutic biomarkers.

miR-137 alleviates focal cerebral ischemic injury in rats by regulating JAK1/STAT1 signaling pathway

The repairing effect and potential mechanism of miR-137 on cerebral ischemic injury in rats was investigated. The volume of cerebral infarction and calculated brain water content was detected by triphenyltetrazolium chloride staining. The expression of inflammatory factors was detected by enzyme-linked immunosorbent assay. The pathological damage of brain tissue was analyzed by hematoxylin and eosin and Nissl staining. The apoptosis in ischemic brain tissue was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling. The levels of STAT1 and JAK1 proteins were analyzed by Western blot. The expression of miR-137 in primary hippocampal neurons was detected by reverse transcription polymerase chain reaction. miR-137 overexpression significantly improved brain damage in rats. miR-137 overexpression can reduce the expression of TNF-α, IL-1β, and IL-6. miR-137 overexpression can reduce the degree of brain tissue damage and inhibit the expression of JAK1 and STAT1 proteins. miR-137 overexpression can reduce oxygen-glucose deprivation (OGD)/R-induced cell damage, improve cell proliferation, and reduce apoptotic rate. JAK1 and STAT1 protein expression was inhibited in hippocampal neurons after OGD/R treatment after transfection with miR-137 mimic. After the addition of the Filgotinib inhibitor, the levels of JAK1 and STAT1 proteins were significantly reduced. The results suggested that miR-137 overexpression can effectively improve ischemic injury after focal cerebral ischemia and protect against by inhibiting JAK1/STAT1 pathway.

LncRNAGAS5 sponges miRNA-221 to promote neurons apoptosis by up-regulated PUMA under hypoxia condition

Objectives: Long noncoding RNAs (lncRNAs) play substantial roles in cerebral ischemia. Growth arrest-specific 5 (GAS5) was reported to be involved in stroke. In the present study, we aimed to investigate the roles of GAS5 in cerebral condition and unveil the underlying mechanism.Method: Transient focal ischemia was induced by intraluminal occlusion of the right Middle cerebral artery occlusion (MCAO) and 2,3,5-triphenyltetrazolium chloride (TTC) staining was used to evaluate the volume of cerebral infarction. RT-qPCR was applied to evaluate the level of GAS5 and miR-221. Fluorescence activated Cell Sorting (FACS) and Terminal deoxynucleotidyl transferased (TUNEL)  were used for detection of apoptosis. Western blotting was applied for protein level. Luciferase assay was applied to reveal the underlying relationship between GAS5 and miR-221 or p53-upregulated modulator of apoptosis (PUMA) and miR-221.Results: The results indicated that GAS5 was up-regulated in MCAO rats and in vitro hypoxia cell model while miR-221 expression was decreased in vitro hypoxia cell model. GAS5 promoted cells apoptosis, while miR-221 inhibited cell apoptosis through regulation of PUMA and downstream JNK/H2AX signaling. Moreover, GAS5 and miR-221 have direct interaction and PUMA was the target of miR-221, indicating that GAS5 regulated PUMA through sponging miR-221.Conclusions: the present study revealed that GAS5 aggravated cell apoptosis in hypoxia condition via miR-221/PUMA axis, which may provide potential targets for the treatment of stroke.

Inhibition of T cell immunoglobulin and mucin-1 (TIM-1) protects against cerebral ischemia-reperfusion injury

Background

The T cell Ig domain and mucin domain (TIM)-1 protein expressed on the surface of Th2 cells regulates the immune response by modulating cytokine production. The present study aimed to investigate the role and possible mechanism of TIM-1 in cerebral ischemia-reperfusion injury.

Methods

Western blot was used to detect TIM-1 and apoptosis-related protein expression, whereas TIM-1 mRNA was examined using quantitative real-time reverse transcription PCR. Flow cytometry and a TdT-mediated biotin-16-dUTP nick-end labeling (TUNEL) assay were used to detect the percentage of apoptotic cells and a pathological examination was performed. The migration of neutrophils and macrophages was analyzed by immunohistochemistry.

Results

Our results suggest that TIM-1 expression was transiently increased 24 h or 48 h following middle cerebral artery occlusion (MCAO)/reperfusion. The infarct size was markedly increased in MCAO, whereas treatment with a TIM-1-blocking mAb could reduce the infarct size. TIM-1 blocking mAb effectively reduced the number of neutrophils, macrophage functionality, cytokine (i.e., IL-6, IL-1β, and TNF-α) and chemokine (i.e., CXCL-1 and CXCL-2) production in the brain tissue. The effect of in vitro T cell damage on neurons was significantly reduced following treatment with a TIM-1 blocking mAb or the knockdown of TIM-1 in co-cultured T cells and neurons.

Conclusion

Take together, these results indicated that TIM-1 blockade ameliorated cerebral ischemia-reperfusion injury. Thus, TIM-1 disruption may serve as a novel target for therapy following MCAO.

Downregulation of microRNA‑451 improves cell migration, invasion and tube formation in hypoxia‑treated HUVECs by targeting MIF

Angiogenesis is a critical process of recovery from cerebrovascular disease. A growing body of evidence has confirmed that microRNAs (miRNAs/miRs) have an important role in the modulation of angiogenesis under physiological and pathological conditions including cerebral ischemia injury (CII). Therefore, the aim of the present study was to explore the function and mechanism of microRNAs in regulating angiogenesis using a cell model of CII. Firstly, a miRNA microarray was performed to analyze miRNA expression in serum samples from patients with cerebral ischemia and the results revealed that miR-451 was one of the miRNAs that was the most significantly downregulated. Subsequently, human umbilical vein endothelial cells (HUVECs) were used as an in vitro model to further explore the mechanisms governing angiogenesis during hypoxia. The results demonstrated that overexpression of miR-451 had a significantly anti-angiogenic effect by suppressing tube formation, migration and wound healing in vitro. By contrast, reducing the expression of miR-451 promoted HUVEC migration and tubulogenesis under normoxic conditions. The present study further identified that macrophage migration inhibitory factor (MIF), an important angiogenic regulator, was a novel target of miR-451 that could reverse the effects of miR-451 on the regulation of angiogenesis in HUVECs under hypoxic or normoxic conditions. These results revealed that downregulation of miR-451 promotes angiogenesis by targeting MIF in hypoxic HUVECs and indicated that miR-451 is a potential candidate for CII therapeutics.

Fabrication and evaluation a transferrin receptor targeting nano-drug carrier for cerebral infarction treatment

After cerebral infarction, the regeneration of microvascular played an important role in the recovery. Ginsenoside Rg1 (Rg1) had good effects on promoting angiogenesis and neuro-protection in cerebral infarction treatment. However, the blood-brain barrier (BBB) restricted Rg1 to enter into cerebral tissue. Transferrin receptor (TfR) was over-expressed in the BBB. In this study, we fabricated a TfR targeting nano-carrier (PATRC) to penetrate the BBB for treatment of cerebral infarction. A TfR targeted peptide was conjugated with the nano-carrier wrapped hydrophobic Rg1. The nanoscale size (132 ± 12 nm), polydispersity index (PDI =0.29) and the zeta potential (-38mv) were tested with dynamic light scattering optical system. Surface morphology (ellipse, mean diameter 122 ± 26 nm) was detected by transmission electron microscope (TEM). PATRC implement cell targeting ability on rat brain microvascular endothelial cells RBE4 in vitro detected by immunofluorescence and flow cytometry methods. Comparing with Rg1 threated group, the PATRC exhibited more prominent ability on the tube formation ability (p < .05) in vitro. Comparing with the Rg1 treated group, PATRC penetrated BBB in vivo detected by HPLC, decreased the brain infarction volume tested with TTC staining and promoted regeneration of microvascular in infarction zone detected by CD31 immunofluorescence. PATRC has great potentiality for wide application in clinic.

MicroRNAs in brain development and cerebrovascular pathophysiology

MicroRNAs (miRNAs) are a class of highly conserved non-coding RNAs with 21-25 nucleotides in length and play an important role in regulating gene expression at the posttranscriptional level via base-paring with complementary sequences of the 3'-untranslated region of the target gene mRNA, leading to either transcript degradation or translation inhibition. Brain-enriched miRNAs act as versatile regulators of brain development and function, including neural lineage and subtype determination, neurogenesis, synapse formation and plasticity, neural stem cell proliferation and differentiation, and responses to insults. Herein, we summarize the current knowledge regarding the role of miRNAs in brain development and cerebrovascular pathophysiology. We review recent progress of the miRNA-based mechanisms in neuronal and cerebrovascular development as well as their role in hypoxic-ischemic brain injury. These findings hold great promise, not just for deeper understanding of basic brain biology but also for building new therapeutic strategies for prevention and treatment of pathologies such as cerebral ischemia.

miR‑29a ameliorates ischemic injury of astrocytes in vitro by targeting the water channel protein aquaporin 4

Ischemic stroke is the main cause of brain injury and results in a high rate of morbidity, disability and mortality. In the present study, we aimed to determine whether miR-29a played a protective role in oxygen glucose deprivation (OGD) injury via regulation of the water channel protein aquaporin 4 (AQP4). Real-time PCR and western blotting were used to assess miR-29a levels and AQP4 protein levels, respectively. Apoptosis was detected by flow cytometry, and lactate dehydrogenase (LDH) was determined by enzyme-linked immunosorbent assay (ELISA). Overexpression of miR-29a was significantly downregulated in OGD-induced primary astrocytes, and transfection with a miR-29a mimic decreased LDH release and apoptosis, and improved cell health in OGD-induced astrocytes. AQP4 was the target of miR-29a, which suppressed AQP4 expression, and knockdown of AQP4 mitigated OGD-induced astrocyte injury. Furthermore, miR-29a regulated AQP4 expression in OGD-induced astrocytes. AQP4 exacerbated astrocyte injury following ischemic stroke, and knockdown of AQP4 protected OGD/RX-induced primary cultured astrocytes against injury. The effect of miR-29a inhibitor on primary astrocytes was lost following AQP4 knockdown. These findings indicated that miR-29a prevented astrocyte injury in vitro by inhibiting AQP4. Thus, miR-29a may protect primary cultured astrocytes after OGD-induced injury by targeting AQP4, and may be a potential therapeutic target for ischemic injury of astrocytes.

Pro- and antiangiogenic therapies: current status and clinical implications

Blood vessels nurture every part of the human body. Consequently, abnormalities in the vasculature are closely associated with a variety of diseases, including cerebral stroke, heart disease, retinopathy, and cancer. Pro- or antiangiogenic therapies can influence these diseases by regulating the growth of new blood vessels from a pre-existing vascular network or dampening excessive blood growth. However, clinical translation of these approaches is slow and challenging. In this review, we discuss recent preclinical approaches to regulate angiogenesis and their potential and risks in a clinical setting.-Rust, R., Gantner, C., Schwab, M. E. Pro- and antiangiogenic therapies: current status and clinical implications.

MicroRNA-based therapeutics in central nervous system injuries

Central nervous system (CNS) injuries, such as stroke, traumatic brain injury (TBI) and spinal cord injury (SCI), are important causes of death and long-term disability worldwide. MicroRNA (miRNA), small non-coding RNA molecules that negatively regulate gene expression, can serve as diagnostic biomarkers and are emerging as novel therapeutic targets for CNS injuries. MiRNA-based therapeutics include miRNA mimics and inhibitors (antagomiRs) to respectively decrease and increase the expression of target genes. In this review, we summarize current miRNA-based therapeutic applications in stroke, TBI and SCI. Administration methods, time windows and dosage for effective delivery of miRNA-based drugs into CNS are discussed. The underlying mechanisms of miRNA-based therapeutics are reviewed including oxidative stress, inflammation, apoptosis, blood-brain barrier protection, angiogenesis and neurogenesis. Pharmacological agents that protect against CNS injuries by targeting specific miRNAs are presented along with the challenges and therapeutic potential of miRNA-based therapies.

MIF protects against oxygen-glucose deprivation-induced ototoxicity in HEI-OC1 cochlear cells by enhancement of Akt-Nrf2-HO-1 pathway

Ischemia and oxidative stress play crucial roles in the pathophysiology of sudden sensorineural hearing loss (SSNHL). Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine and serves an important role in hearing function. The present study was designed to evaluate the effect of MIF on oxygen-glucose deprivation (OGD)-induced ototoxicity and to elucidate its molecular mechanism. In HEI-OC1 auditory cells, OGD reduced cell viability and increased supernatant lactate dehydrogenase (LDH) and MIF in a time-dependent manner. However, the reduced cell viability exerted by OGD was attenuated by antioxidant and MIF. Luciferase reporter assay demonstrated that MIF could activate NF-E2-related factor 2 (Nrf2), and real-time PCR showed increased mRNA expressions of Nrf2 and two Nrf2-responsive genes, including heme oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1). MIF also suppressed oxidative stress induced by OGD, as demonstrated by decreased MDA and increased GSH in cellular supernatant. Inhibition of Nrf2 using siRNA suppressed HO-1 protein expression, the protective effect on OGD-induced injury and decrease in oxidative stress by MIF. Moreover, MIF prevented OGD-induced reduction of Akt1 phosphorylation at Ser473. LY294002, an inhibitor of PI3K/Akt signaling, attenuated the enhancement of Nrf2 protein and protective effect of MIF in OGD-treated cochlear cells. We demonstrate that MIF protects cochlear cells against OGD-induced injury through activation of Akt-Nrf2-HO-1 pathway.

Exosomes Secreted by Adipose-Derived Stem Cells Contribute to Angiogenesis of Brain Microvascular Endothelial Cells Following Oxygen-Glucose Deprivation In Vitro Through MicroRNA-181b/TRPM7 Axis

Adipose-derived stem cells (ADSCs) have been demonstrated to promote cerebral vascular remodeling processes after stroke. However, the exact molecular mechanism by which ADSCs exert protective roles in ischemic stroke is still poorly understood. In this study, we identified the role of exosomal microRNA-181b-5p (181b-Exos) in regulating post-stroke angiogenesis. The results of migration assay and capillary network formation assay showed that exosomes secreted by ADSCs (ADSCs-Exos) promoted the mobility and angiogenesis of brain microvascular endothelial cells (BMECs) after oxygen-glucose deprivation (OGD). Quantitative real-time polymerase chain reaction (qRT-PCR) showed that microRNA-212-5p (miR-212-5p) and miR-181b-5p were upregulated in BMECs subjected to the brain extract of the middle cerebral artery occlusion rats. The migration distance and tube length were increased in BMECs cultured with 181b-Exos. Furthermore, we identified that transient receptor potential melastatin 7 (TRPM7) was a direct target of miR-181b-5p. TRPM7 mRNA and protein levels were declined in BMECs cultured with 181b-Exos, but not in BMECs cultured with 212-Exos. Overexpression of TRPM7 reversed the effects of 181b-Exos on migration and tube formation of BMECs. In addition, 181b-Exos upregulated the protein expression of hypoxia-inducible factor 1α and vascular endothelial cell growth factor, and downregulated the protein expression of tissue inhibitor of metalloproteinase 3. The regulatory effect of 181b-Exos was attenuated by overexpressing TRPM7. Altogether, ADSCs-Exos promote the angiogenesis of BMECs after OGD via miR-181b-5p/TRPM7 axis, suggesting that ADSCs-Exos may represent a novel therapeutic approach for stroke recovery.

Downregulation of circ_008018 protects against cerebral ischemia-reperfusion injury by targeting miR-99a

Circular RNAs (circRNAs) are highly expressed in eukaryotic cells and regulate physiological and pathophysiological processes. However, the role of circRNAs in cerebral ischemia-reperfusion (I/R) injury remains largely unknown. In this study, we found that circ_008018 level was higher in the cortical tissue of mice with middle cerebral artery occlusion as compared to those in the sham group 24 h after reperfusion. Knockdown of circ_008018 attenuated cerebral I/R-induced brain tissue damage and neurological deficits in mice by inducing microRNA miR-99a overexpression. The decreased phosphorylation of Akt and glycogen synthase kinase 3β caused by I/R was partly reversed by circ_008018 silencing or miR-99a overexpression. Taken together, these results provide new insight into the mechanisms of apoptosis resulting from cerebral I/R injury and suggest that targeted inhibition of circ_008018 can protect against subsequent neurological damage.

MiR-103 regulates the angiogenesis of ischemic stroke rats by targeting vascular endothelial growth factor (VEGF)

OBJECTIVES

To investigate the effect of miR-103 on the angiogenesis of ischemic stroke rats via targeting vascular endothelial growth factor (VEGF) at the molecular level.

MATERIALS AND METHODS

Rat models had received the middle cerebral artery occlusion (MCAO) or sham operation before grouping, and cell models of oxygen-glucose deprivation (OGD) were performed. FITC-dextran, matrigel, and Trans-well assays were used to evaluate the vascular density, tube formation, and cell migration respectively. The expression levels of miR-103 and VEGF were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. Dual-luciferase assay was used for analyzing the targeting relationship between miR-103 and VEGF.

RESULTS

We found the reduced miR-103 in rats after MCAO. Down-regulating miR-103 with the miR-103 inhibitor enhanced VEGF, ameliorated the neurological scores, decreased infarct volume, and increased vascular density in rats after MCAO. Besides, in OGD human umbilical vein endothelial cells (HUVECs), inhibition of miR-103 could promote the increase of tube length and the migration of cells. Additionally, we found that miR-103 could directly target VEGF and thereby lead to the down-expression of VEGF. Meanwhile, si-VEGF could reverse the effect of miR-103 inhibitor on angiogenesis in rats subjected to MCAO.

CONCLUSION

Inhibition of miR-103 could promote ischemic stroke angiogenesis and reduce infarction volume via enhancing VEGF, which provides a new target for the clinical treatment of ischemic stroke.

Silencing a Multifunctional microRNA Is Beneficial for Stroke Recovery

Stroke-induced endothelial cell injury leads to destruction of cerebral microvasculature and significant damage to the brain tissue. A subacute phase of cerebral ischemia is associated with regeneration involving the activation of vascular remodeling, neuroplasticity, neurogenesis, and neuroinflammation processes. Effective restoration and improvement of blood supply to the damaged brain tissue offers a potential therapy for stroke. microRNAs (miRNAs) are recently identified small RNA molecules that regulate gene expression and significantly influence the essential cellular processes associated with brain repair following stroke. A number of specific miRNAs are implicated in regulating the development and propagation of the ischemic tissue damage as well as in mediating post-stroke regeneration. In this review, I discuss the functions of the miRNA miR-155 and the effect of its in vivo inhibition on brain recovery following experimental cerebral ischemia. The article introduces new and unexplored approach to cerebral regeneration: regulation of brain tissue repair through a direct modulation of specific miRNA activity.

MicroRNA-130a regulates cerebral ischemia-induced blood-brain barrier permeability by targeting Homeobox A5

Blood-brain barrier (BBB) disruption plays a critical role in brain injury induced by cerebral ischemia, and preserving BBB integrity during ischemia could alleviate cerebral injury. We examined the role of miR-130a in ischemic BBB disruption by using models of rat middle cerebral artery occlusion and cell oxygen-glucose deprivation. We found that ischemia significantly increased microRNA-130a (miR-130a) level and that miR-130a was predominantly from brain microvascular endothelial cells. Antagomir-130a, an antagonist of miR-130a, could attenuate brain edema, lower BBB permeability, reduce infarct volume, and improve neurologic function. MiR-130a overexpression induced by miR-130a mimic increased monolayer permeability, and intercellular inhibition of miR-130a by a miR-130a inhibitor suppressed oxygen-glucose deprivation-induced increase in monolayer permeability. Moreover, dual luciferase reporter system showed that Homeobox A5 was the direct target of miR-130a. MiR-130a, by inhibiting Homeobox A5 expression, could down-regulate occludin, thereby increasing BBB permeability. Our results suggested that miR-130a might be implicated in ischemia-induced BBB dysfunction and serve as a target for the treatment of ischemic stroke.-Wang, Y., Wang, M.-D., Xia, Y.-P., Gao, Y., Zhu, Y.-Y., Chen, S.-C., Mao, L., He, Q.-W., Yue, Z.-Y., Hu, B. MicroRNA-130a regulates cerebral ischemia-induced blood-brain barrier permeability by targeting Homeobox A5.

Endothelial progenitor cells enhance blood-brain barrier permeability in subacute stroke

OBJECTIVE

To study the association among endothelial progenitor cells (EPCs), subacute blood-brain barrier (BBB) permeability, and clinical outcome after ischemic stroke, determining the micro RNAs of EPCs responsible for good clinical outcome.

METHODS

We included consecutive patients with nonlacunar acute ischemic strokes in the territory of a middle cerebral artery and ages between 18 and 80 years. Clinical outcome was defined as modified Rankin Scale score at 3 months. Neuroimaging was performed at day 0 and 7 by MRI, including assessment of BBB permeability by dynamic contrast enhancement. EPCs were isolated from peripheral venous blood, quantified, and submitted to in vitro functional tests, including migratory and angiogenic assays. Stroke hemodynamics were evaluated serially by ultrasound. Statistical significance was set at p < 0.05.

RESULTS

We included 45 patients; mean age was 70.0 ± 10.0 years. The in vitro functional properties of EPCs were associated with BBB permeability, particularly at day 7. The number of each EPC subset at both timepoints was not associated with BBB permeability. Permeability of BBB at day 7 was independently associated with improved clinical outcome (odds ratio 0.897; 95% confidence interval 0.816-0.986; p = 0.025). The EPCs (CD34+ cell subset) of patients with good clinical outcome showed 24 differentially expressed miRNAs, with a common effect on adherens junction pathway.

CONCLUSIONS

The functional properties of EPCs are associated with enhanced subacute permeability of BBB and improved clinical outcome after acute ischemic stroke.

A causal mediation model of ischemia reperfusion injury in the retina

The goal of this study is to develop a model that explains the relationship between microRNAs, transcription factors, and their co-target genes. This relationship was previously reported in gene regulatory loops associated with 24 hour (24h) and 7 day (7d) time periods following ischemia-reperfusion injury in a rat's retina. Using a model system of retinal ischemia-reperfusion injury, we propose that microRNAs first influence transcription factors, which in turn act as mediators to influence transcription of genes via triadic regulatory loops. Analysis of the relative contributions of direct and indirect regulatory influences on genes revealed that a substantial fraction of the regulatory loops (69% for 24 hours and 77% for 7 days) could be explained by causal mediation. Over 40% of the mediated loops in both time points were regulated by transcription factors only, while about 20% of the loops were regulated entirely by microRNAs. The remaining fractions of the mediated regulatory loops were cooperatively mediated by both microRNAs and transcription factors. The results from these analyses were supported by the patterns of expression of the genes, transcription factors, and microRNAs involved in the mediated loops in both post-ischemic time points. Additionally, network motif detection for the mediated loops showed a handful of time specific motifs related to ischemia-reperfusion injury in a rat's retina. In summary, the effects of microRNAs on genes are mediated, in large part, via transcription factors.

Vascular Endothelial Growth Factor Isoform-B Stimulates Neurovascular Repair After Ischemic Stroke by Promoting the Function of Pericytes via Vascular Endothelial Growth Factor Receptor-1

Ischemic stroke triggers endogenous angiogenic mechanisms, which correlates with longer survival in patients. As such, promoting angiogenesis appears to be a promising approach. Experimental studies investigated mostly the potent angiogenic factor vascular endothelial growth factor isoform-A (VEGF-A). However, VEGF-A increases the risk of destabilizing the brain microvasculature, thus hindering the translation of its usage in clinics. An attractive alternative VEGF isoform-B (VEGF-B) was recently reported to act as a survival factor rather than a potent angiogenic factor. In this study, we investigated the therapeutic potential of VEGF-B in ischemic stroke using different in vivo and in vitro approaches. We showed that the delayed intranasal administration of VEGF-B reduced neuronal damage and inflammation. Unexpectedly, VEGF-B stimulated the formation of stable brain microvasculature within the injured region by promoting the interaction between endothelial cells and pericytes. Our data indicate that the effects of VEGF-B were mediated via its specific receptor VEGF receptor-1 (VEGFR-1) that is predominately expressed in brain pericytes. Importantly, VEGF-B promoted the survival of pericytes, and not brain endothelial cells, by inducing expression of the anti-apoptotic protein B-cell lymphoma 2 (Bcl-2) and the main protein involved in energy homeostasis AMP-activated protein kinase α (AMPKα). Moreover, we showed that VEGF-B stimulated the pericytic release of factors stimulating a "reparative angiogenesis" that does not compromise microvasculature stability. Our study unraveled hitherto unknown role of VEGF-B/VEGFR-1 signaling in regulating the function of pericytes. Furthermore, our findings suggest that brain microvasculature stabilization via VEGF-B constitutes a safe therapeutic approach for ischemic stroke.