microRNA-451 protects neurons against ischemia/reperfusion injury-induced cell death by targeting CELF2

Investigating microRNAs as biomarkers in disorders of consciousness: a longitudinal multicenter study

MicroRNAs (miRNAs) are involved in gene regulation and may affect secondary brain injury and recovery in patients with disorders of consciousness (DoC). This study investigated the role of five miRNAs (150-5p, 132-3p, 23b-3p, 451a, and 16-5p) in prolonged DoC. miRNA levels were assessed in serum samples from 30 patients with unresponsive wakefulness syndrome or minimally conscious state due to traumatic or hypoxic-ischemic brain injury (TBI, HIBI) at baseline (1-3 months) and 6 months post-injury. Patients' diagnoses were determined using the Coma Recovery Scale revised, and functional outcomes were evaluated 6 months after injury with the Glasgow Outcome Scale Extended (GOSE) and the Functional Independence Measure (FIM). Compared to healthy controls, patients with TBI had lower levels of miRNAs 150-5p, 132-3p, and 23b-3p at baseline, while patients with HIBI had lower levels of miRNA 150-5p at baseline and 6 months post-injury and a reduction of miRNA 451a at baseline. Higher levels of miRNAs 132-3p and 23b-3p were associated with better outcomes in TBI patients as indicated by GOSE and FIM scores. This study highlights distinct miRNA dysregulated patterns in patients with prolonged DoC, dependent on etiology and post-injury time, and suggests that miRNAs 132-3p and 23b-3p may serve as prognostic biomarkers.

Decreased miR-451a in cerebrospinal fluid, a marker for both cognitive impairment and depressive symptoms in Alzheimer's disease

Background: Alzheimer's disease (AD) patients are often accompanied by depressive symptoms, but its underlying mechanism remains unclear. The present study aimed to explore the potential role of microRNAs in the comorbidity of AD and depression. Methods: The miRNAs associated with AD and depression were screened from databases and literature and then confirmed in the cerebrospinal fluid (CSF) of AD patients and different ages of transgenic APP/PS1 mice. AAV9-miR-451a-GFP was injected into the medial prefrontal cortex (mPFC) of APP/PS1 mice at seven months, and four weeks later, a series of behavioral and pathological analyses were performed. Results: AD patients had low CSF levels of miR-451a, which was positively correlated with the cognitive assessment score, but negatively with their depression scale. In the mPFC of APP/PS1 transgenic mice, the miR-451a levels also decreased significantly in the neurons and microglia. Specific virus vector-induced overexpression of miR-451a in the mPFC of APP/PS1 mice ameliorated AD-related behavior deficits and pathologies, including long-term memory defects, depression-like phenotype, β-amyloid load, and neuroinflammation. Mechanistically, miR-451a decreased the expression of neuronal β-secretase 1 of neurons through inhibiting Toll-like receptor 4/Inhibitor of kappa B Kinase β/ Nuclear factor kappa-B signaling pathway and microglial activation by inhibiting activation of NOD-like receptor protein 3, respectively. Conclusion: This finding highlighted miR-451a as a potential target for diagnosing and treating AD, especially for those with coexisting symptoms of depression.

Stress Granules and Acute Ischemic Stroke: Beyond mRNA Translation

Ischemic stroke is a leading cause of death and disability worldwide. Following an ischemic insult, cells undergo endoplasmic reticulum (ER) stress, which increases the ER’s protein-folding and degradative capacities and blocks the global synthesis of proteins by phosphorylating the eukaryotic translation initiation factor 2-alpha (eIF2α). Phosphorylation of eIF2α is directly related to the dynamics of stress granules (SGs), which are membraneless organelles composed of RNA-binding proteins and mRNA. SGs play a critical role in mRNA metabolism and translational control. Other translation factors are also linked to cellular pathways, including SG dynamics following a stroke. Because the formation of SGs is closely connected to mRNA translation, it is interesting to study the relationship between SG dynamics and cellular outcome in cases of ischemic damage. Therefore, in this review, we focus on the role of SG dynamics during cerebral ischemia.

Identification of let-7f and miR-338 as plasma-based biomarkers for sporadic amyotrophic lateral sclerosis using meta-analysis and empirical validation

Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disease that in most cases occurs sporadic (sALS). The disease is not curable, and its pathogenesis mechanisms are not well understood yet. Given the intricacy of underlying molecular interactions and heterogeneity of ALS, the discovery of molecules contributing to disease onset and progression will open a new avenue for advancement in early diagnosis and therapeutic intervention. Here we conducted a meta-analysis of 12 circulating miRNA profiling studies using the robust rank aggregation (RRA) method, followed by enrichment analysis and experimental verification. We identified miR-451a and let-7f-5p as meta-signature miRNAs whose targets are involved in critical pathogenic pathways underlying ALS, including ‘FoxO signaling pathway’, ‘MAPK signaling pathway’, and ‘apoptosis’. A systematic review of 7 circulating gene profiling studies elucidated that 241 genes up-regulated in sALS circulation with concomitant being targets of the meta-signature miRNAs. Protein–protein interaction (PPI) network analysis of the candidate targets using MCODE algorithm revealed the main subcluster is involved in multiple cascades eventually leads apoptosis, including ‘positive regulation of neuron apoptosis. Besides, we validated the meta-analysis results using RT-qPCR. Indeed, relative expression analysis verified let-7f-5p and miR-338-3p as significantly down-regulated and up-regulated biomarkers in the plasma of sALS patients, respectively. Receiver operating characteristic (ROC) analysis also highlighted the let-7f-5p and miR-338-3p potential as robustness plasma biomarkers for diagnosis and potential therapeutic targets of sALS disease.

Effect of Edaravone on MicroRNA Expression in Exosomes after Hepatic Ischemia-reperfusion Injury

BACKGROUND AND OBJECTIVE

Hepatic ischemia-reperfusion injury (HIRI) results in serious complications after liver resection and transplantation. Edaravone (ED) has a protective effect on IRI. This study was designed to evaluate whether ED could protect the liver of rats from HIRI injury and explored its exosomal miRNA-related mechanism.

METHODS

The sham group, hepatic ischemia/reperfusion (IR group), and hepatic ischemia/reperfusion + edaravone (ED group) models were established. We determined the protective effect of ED by measuring alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), superoxide dismutase (SOD); enzyme-linked immunosorbent assay for tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β); hematoxylin-eosin staining and immunohistochemistry for histopathological changes. Exosomal miRNAs were subjected to second-generation sequencing to identify their differential expression. The results were analyzed using bioinformatics methods and validated using real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

HIRI rats showed higher levels of ALT, AST, oxidative stress, and inflammatory markers; ED attenuated these effects. The sequencing results showed 6 upregulated and 13 downregulated miRNAs in the IR vs. sham groups, 10 upregulated and 10 downregulated miRNAs in the ED vs. IR groups. PC-3p-190-42101 was screened as an overlapping differentially expressed miRNA, and RT-qPCR validation showed that its expression in HIRI rats was significantly decreased; ED prevented this downregulation. Moreover, the expression of PC-3P-190-42101 was significantly correlated with the level of inflammatory factors.

CONCLUSION

These findings indicate that ED can regulate the level of inflammatory factors by affecting the expression of miRNA PC-3p-190-42101 in plasma exosomes to protect the liver from IRI.

Selecting Hub Genes and Predicting Target Genes of microRNAs in Tuberculosis via the Bioinformatics Analysis

Tuberculosis (TB) is the world's most prevalently infectious disease. Molecular mechanisms behind tuberculosis remain unknown. microRNA (miRNA) is involved in a wide variety of diseases. To validate the significant genes and miRNAs in the current sample, two messenger RNA (mRNA) expression profile datasets and three miRNA expression profile datasets were downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed (DE) genes (DEGs) and miRNAs (DE miRNAs) between healthy and TB patients were filtered out. Enrichment analysis was executed, and a protein-protein interaction (PPI) network was developed to understand the enrich pathways and hub genes of TB. Additionally, the target genes of miRNA were predicted and overlapping target genes were identified. We studied a total of 181 DEGs (135 downregulated and 46 upregulated genes) and two DE miRNAs (2 downregulated miRNAs) from two gene profile datasets and three miRNA profile datasets, respectively. 10 hub genes were defined based on high degree of connectivity. A PPI network's top module was constructed. The 23 DEGs identified have a significant relationship with miRNAs. 25 critically significant Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were discovered. The detailed study revealed that, in tuberculosis, the DE miRNA and DEGs form an interaction network. The identification of novel target genes and main pathways would aid with our understanding of miRNA's function in tuberculosis progression.

MicroRNA-451 Aggravates Kainic Acid-induced Seizure and Neuronal Apoptosis by Targeting GDNF

AIM

Epilepsy is a common and serious neurological disease that causes recurrent episodes, but its molecular mechanism remains unclear. Abnormal miRNA expression is associated with epilepsy, including miR-451. This research investigated the role of miR-451 in seizure and its detailed mechanism.

METHODS

The seizure mice model was induced by kainic acid (KA) injection to the right lateral cerebral ventricle. Behavioral changes in mice were observed and evaluated by the Racine Scale. The miR-451 knockout mice were established by adenovirus infection. The in vitro model was performed by miR-451 mimics transfected HEK-293 cells. The amount of neuronal death and morphological changes were evaluated by Nissl staining and H&E staining.

RESULTS

The results showed that miR-451 is up regulated in KA-induced seizure models and miR- 451 knockout decreased the behavior score and improved the pathological changes of the hippocampus. Besides, MiR-451 knockout inhibited the apoptosis of hippocampal neurons. Bioinformatics studies have shown that glial cell line-derived neurotrophic factor (GDNF) is a target gene of miR-451. MiR-451 could negatively regulate the expression of GDNF. GDNF overexpression could reverse the effect of miR-451 on KA induced brain injury and neuronal apoptosis.

CONCLUSION

This research demonstrates that miR-451 can affect the behavior of KA-induced epilepsy mice and hippocampal neuronal damage by regulating GDNF expression. The results would provide an experimental foundation for further research about the potential contribution of mi- RNAs to epilepsy pathophysiology.

Triclosan regulates alternative splicing events of nerve-related genes through RNA-binding protein CELF2 to induce zebrafish neurotoxicity

Herein, we demonstrated that triclosan (TCS) induced neurotoxicity mediated by pre-mRNA alternative splicing (AS). TCS exposure resulted in a series of phenotypic malformations, abnormal locomotor behavior, circadian rhythm disorder and inhibited AChE activity. High throughput mRNA sequencing revealed that TCS regulated the AS events of nerve-related genes. Meanwhile, abnormal expression was observed in marker genes related to nerve cell migration, axon guidance and myelination. The expression of mitochondrial apoptosis activator bcl2l11 was significantly increased under TCS exposure. Interestingly, CELF2 as one of the important RNA-binding proteins was closely related to the AS events, and its mRNA and protein expression levels were significantly increased in zebrafish brain under acute or chronic TCS exposure. Functional knock-down and over-expression of celf2 confirmed that TCS led to nervous system injury and developmental defects through the CELF2-mediated AS events of genes (mbpa, mef2d, u2af2b and matn3b). Histopathological injury, phenotypic malformation, abnormal locomotor behavior and changes in neuromarkers all confirmed the biological functions of CELF2 in zebrafish brain. These findings demonstrate that TCS might regulate some of the AS events of nerve-related genes through upregulating the expression of CELF2. Thus, CELF2 may serve as a target for the prevention, diagnosis and treatment of contaminant-induced neurological diseases.

miR-451 protects against ischemic stroke by targeting Phd3

Ischemic stroke still remains a therapeutic challenge due to its complex pathogenesis and implications. By screening biomarkers in the peripheral blood of ischemic stroke patients, miR-451 was identified as a differentially expressed miRNA along the disease course of ischemic stroke. To investigate the role of miR-451, middle cerebral artery occlusion (MCAO) was performed as an ischemic stroke model in mice. Intracerebroventricular administration of miR-451 mimic in the MCAO mice significantly decreased infarct size, while miR-451 inhibitor significantly increased infarct size. To understand the molecular mechanism of the protective effect of miR-451, Phd3 (also Egln3) was validated as a new miR-451 target. Either fewer or more Phd3-positive cells were observed in brain sections from mice receiving miR-451 mimic or inhibitor, respectively. In addition, the levels of p53 (a known Phd3 target) were significantly downregulated when the levels of Phd3 were reduced, suggesting its participation in reducing apoptosis after the miR-451 administration. Indeed, reduced apoptosis upon miR-451 mimic administration was detected by TUNEL staining. In conclusion, this study demonstrated a new protective role of miR-451 in cerebral ischemia and identified Phd3 as a novel miR-451 target, linking the mechanism to the involvement of p53 in the regulation of apoptosis during the pathogenesis of ischemic stroke.

GAS5 knockdown alleviates spinal cord injury by reducing VAV1 expression via RNA binding protein CELF2

Long non-coding RNA growth arrest specific transcript 5 (GAS5) has been found to be implicated in the pathogenesis of central nervous diseases and to be a contributor to hypoxic brain injury. However, the roles and molecular mechanisms of GAS5 in spinal cord injury (SCI) have not thoroughly investigated. Here, we reported that GAS5 knockdown improved rat locomotor function and alleviated pathological damage of spinal cord tissues by reducing oxidative stress, caspase-3 activity and vav guanine nucleotide exchange factor 1 (VAV1) expression in SCI rat models. GAS5 knockdown inhibited the increase of malondialdehyde (MDA) level and cell apoptotic rate induced by oxygen-glucose deprivation (OGD) and weakened the inhibitory effects of OGD on superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and cell viability in RN-Sc cells, suggesting that GAS5 loss mitigated OGD-triggered oxidative stress and cell injury in RN-Sc cells. Molecular mechanism explorations revealed that GAS5 recruited CUGBP, Elav-like family member 2 (CELF2) to the coding region of VAV1 mRNA, resulting in the increase of VAV1 mRNA stability and expression levels. VAV1 knockdown weakened OGD-induced oxidative stress and cell injury in RN-Sc cells. VAV1 loss alleviated GAS5-induced oxidative stress and cell injury in OGD-treated RN-Sc cells. As a conclusion, our findings suggested that GAS5 aggravated SCI by increasing VAV1 expression via binding with CELF2, deepening our understanding on function and molecular basis of GAS5 in SCI.

Deletion of MicroRNA-144/451 Cluster Aggravated Brain Injury in Intracerebral Hemorrhage Mice by Targeting 14-3-3ζ

This study aims at evaluating the importance and its underlying mechanism of the cluster of microRNA-144/451 (miR-144/451) in the models with intracerebral hemorrhage (ICH). A model of collagenase-induced mice with ICH and a model of mice with simple miR-144/451 gene knockout (KO) were used in this study. Neurodeficits and the water content of the brain of the mice in each group were detected 3 days after collagenase injection. The secretion of proinflammatory cytokines, such as tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β), as well as certain biomarkers of oxidative stress, was determined in this study. The results revealed that the expression of miR-451 significantly decreased in the mice with ICH, whereas miR-144 showed no significant changes. KO of the cluster of miR-144/451 exacerbated the neurological deficits and brain edema in the mice with ICH. Further analyses demonstrated that the KO of the cluster of miR-144/451 significantly promoted the secretion of TNF-α and IL-1β and the oxidative stress in the perihematomal region of the mice with ICH. In addition, the miR-144/451's depletion inhibited the regulatory axis' activities of miR-451-14-3-3ζ-FoxO3 in the mice with ICH. In conclusion, these data demonstrated that miR-144/451 might protect the mice with ICH against neuroinflammation and oxidative stress by targeting the pathway of miR-451-14-3-3ζ-FoxO3.

Long noncoding RNA GAS5 ameliorates chronic constriction injury induced neuropathic pain in rats by modulation of the miR-452-5p/CELF2 axis

Neuropathic pain is a type of spontaneous pain that causes damage to the central nervous system. Long noncoding RNAs (lncRNAs) participate in the progression of various nervous system diseases, including neuropathic pain. However, the biological function of GAS5 in neuropathic pain remains unclear. Our findings revealed that GAS5 was downregulated in chronic constriction injury (CCI) rats. Besides, ELISA showed that the concentration of IL-6, TNF-α, and IL-1β were reduced by overexpressed GAS5 in spinal cord homogenates of CCI rats. Moreover, mechanical allodynia and thermal hyperalgesia in CCI rats were inhibited by GAS5 overexpression, suggesting that GAS5 overexpression attenuated neuropathic pain. Subsequently, we found that GAS5 served as a sponge for miR-452-5p in CCI rats and CELF2 was the downstream target of miR-452-5p. Finally, through a rescue assay, we found that GAS5 ameliorated neuropathic pain in CCI rats by sponging miR-452-5p to regulate CELF2 expression. Our study confirmed that GAS5 ameliorated neuropathic pain in rats by modulation of the miR-452-5p/CELF2 axis, which may provide some clues for neuropathic pain treatment.

Non-coding RNAs participate in the ischemia-reperfusion injury

Ischemia, being defined as blood supply deficiency is involved in the pathogenesis of a number of life-threatening conditions such as myocardial infarction and cerebral stroke. Assessment of the molecular pathology of these conditions has led to identification of the role of reperfusion in induction and aggravation of tissue injury and necrosis. Thus, the term "ischemia/ reperfusion (I/R) injury" has been introduced. This process involves aberrant regulation of the mitochondrial function, apoptotic and autophagic pathways and signal transducers. More recently, non-coding RNAs including long non-coding RNAs (lncRNAs) ad microRNAs (miRNAs) have been shown to influence I/R injury. Animal studies and clinical investigations have shown up-/down-regulation of tens of lncRNAs and miRNAs in this process. In the current study, we summarize the role of these transcripts in the pathophysiology of I/R injury and their potential as biomarkers for detection of extent of tissue injury.

Long non-coding RNA ROR sponges miR-138 to aggravate hypoxia/reoxygenation-induced cardiomyocyte apoptosis via upregulating Mst1

BACKGROUND

Hypoxia/reoxygenation (H/R) injury of cardiomyocytes causes an irreversible damage to heart and largely results in acute myocardial infarction. Study has indicated lncRNA ROR aggravates myocardial ischemia/reperfusion (I/R) injury. Also, lncRNA ROR sponges miR-138 to promote osteogenesis. MiR-138 involves in hypoxic pulmonary vascular remodelling by targeting Mst1. However, the interaction between lncRNA ROR, miR-138 and Mst1 involved in myocardial H/R injury is still unknown.

METHODS

H9C2 cells were used to establish H/R injury model. The expression levels of lncRNA ROR and miR-138 were modified by transfection with the miR-138 mimics or lncRNA ROR overexpression plasmid. MTT and flow cytometry analysis were performed to detect cell proliferation and apoptosis. Dual luciferase reporter assay was used to determine interaction between lncRNA ROR and miR-138 or miR-138 and Mst1. Expression levels of lncRNA ROR, miR-138, Mst1 and apoptosis-related markers were determined by qRT-PCR or western blotting.

RESULTS

LncRNA ROR was significantly up-regulated, while miR-138 was obviously down-regulated in H/R-induced injury of H9C2 cells. Furthermore, miR-138 overexpression alleviated cardiac cell apoptosis induced by H/R injury. Mst1 was revealed to be a target of miR-138 and negatively regulated by miR-138. Mst1 overexpression reversed the protective effects of miR-138 on H/R injury of H9C2 cells. LncRNA ROR was identified as a sponge for miR-138. MiR-138 could protect H9C2 cells form H/R injury induced by lncRNA ROR overexpression.

CONCLUSION

Our study provides that lncRNA ROR sponges miR-138 to aggravate H/R-induced myocardial cell injury by upregulating the expression of Mst1.

The Role of Reactive Oxygen Species in Arsenic Toxicity

Arsenic poisoning is a global health problem. Chronic exposure to arsenic has been associated with the development of a wide range of diseases and health problems in humans. Arsenic exposure induces the generation of intracellular reactive oxygen species (ROS), which mediate multiple changes to cell behavior by altering signaling pathways and epigenetic modifications, or cause direct oxidative damage to molecules. Antioxidants with the potential to reduce ROS levels have been shown to ameliorate arsenic-induced lesions. However, emerging evidence suggests that constructive activation of antioxidative pathways and decreased ROS levels contribute to chronic arsenic toxicity in some cases. This review details the pathways involved in arsenic-induced redox imbalance, as well as current studies on prophylaxis and treatment strategies using antioxidants.

Upregulation of miR-376c-3p alleviates oxygen-glucose deprivation-induced cell injury by targeting ING5

Background

The expression level of miR-376c-3p is significantly lower in infants with neonatal hypoxic-ischemic encephalopathy (HIE) than in healthy infants. However, the biological function of this microRNA remains largely elusive.

Methods

We used PC-12 and SH-SY5Y cells to establish an oxygen–glucose deprivation (OGD) cell injury model to mimic HIE in vitro. The miR-376c-3p expression levels were measured using quantitative reverse transcription PCR. The CCK-8 assay and flow cytometry were utilized to evaluate OGD-induced cell injury. The association between miR-376c-3p and inhibitor of growth 5 (ING5) was validated using the luciferase reporter assay. Western blotting was conducted to determine the protein expression of CDK4, cyclin D1, Bcl-2 and Bax.

Results

MiR-376c-3p was significantly downregulated in the OGD-induced cell injury model. Its overexpression elevated cell viability and impaired cell cycle G0/G1 phase arrest and apoptosis in PC-12 and SH-SY5Y cells after OGD. Downregulation of miR-376c-3p gave the opposite results. We further demonstrated that ING5 was a negatively regulated target gene of miR-376c-3p. Importantly, ING5 knockdown had a similar effect to miR-376c-3p-mediated protective effects against cell injury induced by OGD. Its overexpression abolished these protective effects.

Conclusion

Our data suggest that miR-376c-3p downregulated ING5 to exert protective effects against OGD-induced cell injury in PC-12 and SH-SY5Y cells. This might represent a novel therapeutic approach for neonatal HIE treatment.

Propofol-mediated cardioprotection dependent of microRNA-451/HMGB1 against myocardial ischemia-reperfusion injury

Administration of propofol at the time of reperfusion has shown to protect the heart from ischemia and reperfusion (I/R) injury. The aim of the present study was to investigate the molecular mechanism underling the cardioprotective effect of propofol against myocardial I/R injury (MIRI) in vivo and in vitro. Rat heart I/R injury was induced by ligation of the left anterior descending (LAD) artery for 30 min followed by 2-hr reperfusion. Propofol pretreatment (0.01 mg/g) was performed 10 min before reperfusion. In vitro MIRI was investigated in cultured cardiomyocytes H9C2 following hypoxia/reoxygenation (H/R) injuries. Propofol pretreatment in vitro was achieved in the medium supplemented with 25 μmol/L propofol before H/R injuries. Propofol pretreatment significantly increased miRNA-451 expression, decreased HMGB1 expression, reduced infarct size, and I/R-induced cardiomyocyte apoptosis in rat hearts undergoing I/R injuries. Knockdown of miRNA-451 48 hr before I/R injury was found to increase HMGB1 expression, infarct size, and I/R-induced cardiomyocyte apoptosis in rat hearts in the presence of propofol pretreatment. These in vivo findings were reproduced in vivo that knockdown of miRNA-451 48 hr before H/R injuries increased HMGB1 expression and H/R-induced apoptosis in cultured H9C2 supplemented with propofol. In addition, luciferase activity assays and gain-of-function studies found that propofol could decrease HMGB1, the target of miRNA-541. Taken together our findings provide a first demonstration that propofol-mediated cardioprotection against MIRI is dependent of microRNA-451/HMGB1. The study provides a novel target to prevent I/R injury during propofol anesthesia.

MicroRNA‑451 relieves inflammation in cerebral ischemia‑reperfusion via the Toll‑like receptor 4/MyD88/NF‑κB signaling pathway

The present study was designed to investigate the role of microRNA-451 (miRNA-451) on cerebral ischemia-reperfusion and to explore its possible mechanism. The expression of miRNA-451 was downregulated in rats with cerebral ischemia-reperfusion. In an in vitro model of cerebral ischemia-reperfusion, the downregulation of miRNA-451 increased inflammation, demonstrated by increased levels of tumor necrosis factor α, interleukin (IL)-1b, IL-6 and IL-18. However, the upregulation of miRNA-451 expression decreased inflammation in the same in vitro model of cerebral ischemia-reperfusion. In addition, it was found that the downregulation of miRNA-451 induced the expression of Toll-like receptor 4 (TLR4), myeloid differentiation primary response protein MyD88 (MyD88) and nuclear factor-κB (NF-κB)/p65. Moreover, the administration of a MyD88 inhibitor, ST 2825, reduced the expression of MyD88 and NF-κB/p65 in the in vitro model of cerebral ischemia-reperfusion, inhibiting the effects of miRNA-451 upregulation on inflammation. A TLR4 inhibitor, TAK-242, was used to reduce the expression of TLR4 in the in vitro model of cerebral ischemia-reperfusion. TAK-242 suppressed the effects of miRNA-451 downregulation on inflammation. The present study suggested that miRNA-451 regulated cerebral ischemia-reperfusion-induced inflammation, which is mediated through the TLR4/MyD88/NF-κB signaling pathway.

Potential Neuroprotective Effect of miR-451 Against Cerebral Ischemia/Reperfusion Injury in Stroke Patients and a Mouse Model

OBJECTIVE

Recently, microRNAs (miRs) have been reported to be novel regulators in ischemic stroke. In this study, we investigated the pattern of miR-451 expression along with its clinical application in human ischemic stroke and in an in vivo mouse model.

METHODS

The level of miR-451 was evaluated in patients and mice after ischemic stroke. National Institute of Health Stroke Scale scores and brain infarct volume were analyzed to the correlation of miR-451 expression and clinical information. In addition, blood samples and brain tissues were collected from an established middle cerebral artery occlusion model consisting of 12 adult male mice at 24 hours after the middle cerebral artery occlusion.

RESULTS

The results showed that miR-451 levels in the circulating blood of ischemic stroke patients were greatly decreased compared with the control. Further correlation analysis revealed a negative association between miR-451 and National Institute of Health Stroke Scale scores (r = -0.6104, P < 0.001) and infarct volume (r = -0.5442, P < 0.001). Moreover, miR-451 was down-regulated in response to middle cerebral artery occlusion in vivo, along with a negative correlation between miR-451 in brain and blood (r = 0.9240, P < 0.01). In addition, forced expression of miR-451 weakened ischemic brain infarction and apoptosis levels in focal ischemia-stroked mice, while downregulation of miR-451 significantly augmented ischemic injury.

CONCLUSIONS

In conclusion, miR-451 displays the neuroprotective effect in ischemic stroke and might serve as a novel therapeutic target of ischemic stroke.

Upregulation of MicroRNA-128 in the Peripheral Blood of Acute Ischemic Stroke Patients is Correlated with Stroke Severity Partially through Inhibition of Neuronal Cell Cycle Reentry

MiR-128, one of the most enriched miRNAs in the human brain, has been reported to protect MCAO mice via inhibiting P38α MAPK. Whether it is involved in pathogenesis in acute ischemic stroke patients remains to be determined. The present study focused on the clinical importance of miR-128 and its underlying mechanisms. We detected miR-128 levels in the circulating lymphocytes, neutrophils, and plasma of acute ischemic stroke patients by using RT-PCR. miR-128 levels were significantly elevated in circulating lymphocytes, neutrophils, and plasma of patients with acute ischemic stroke. In addition, miR-128 levels in circulating lymphocytes correlated positively with the infarction volume, NIHSS scores at 7 days and mRS at 90 days after ischemic stroke onset. Subsequent KEGG pathway analysis showed that the MAPK signaling pathway and cell cycle are among the pathways targeted by miR-128. Although no correlation was found between miR-128 in plasma and peripheral inflammatory cell numbers, miR-128 decreased in the penumbra and increased in the infarction core of ipsilateral brain tissues in MCAO mice. Moreover, an in vitro study demonstrated that miR-128 antagomir aggravated primary neuronal damage and exacerbated cell cycle reactivation induced by OGD/R stimulation; the underlying mechanism involved increasing cyclin A2, PTEN, and ERK expression and promoting phosphorylation of PTEN and ERK. From the above results, we concluded that the upregulation of miR-128 in circulating lymphocytes of acute ischemic stroke patients was correlated with stroke severity and miR-128 antagomir exacerbated ischemia-reperfusion induced neuronal injury via promoting neuronal cell cycle reentry.