MicroRNA-338-5p alleviates cerebral ischemia/reperfusion injury by targeting connective tissue growth factor through the adenosine 5'-monophosphate-activated protein kinase/mammalian target of rapamycin signaling pathway

CircNCOA4 knockdown attenuates OGD-induced neuron injury through miR-338-5p/PDE4B axis

Circular RNAs (circRNAs) have been revealed to be involved in the pathology of acute ischemic stroke (AIS). Herein, we aimed to study the role and mechanism of circNCOA4 in ischemic stroke. The neuron-like cell line SK-N-SH of the experiment group was cultured in oxygen-glucose deprivation (OGD) condition. Cell viability and apoptosis were evaluated by cell counting kit-8 and flow cytometry. The oxidative damage and endoplasmic reticulum stress (ERS) were analyzed by measuring the production of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), and ERS-related markers. The binding between miR-338-5p and circNCOA4 or PDE4B (Phosphodiesterase 4B) was confirmed using dual-luciferase reporter and RIP assays. The commercial kit was used for exosome separation. The levels of circNCOA4 and PDE4B were increased, while miR-338-5p expression was decreased by OGD stimulation. OGD stimulation resulted in the apoptosis of neurons and induced oxidative damage and ERS, these effects were attenuated by circNCOA4 knockdown, while reinforced by circNCOA4 overexpression. Mechanistically, circNCOA4 acted as a sponge for miR-338-5p, and PDE4B was a target of miR-338-5p. MiR-338-5p inhibition reversed the neuroprotective effects of circNCOA4 silencing on neurons. Besides, miR-338-5p overexpression could abolish OGD-induced neuron injury, which was reversed by PDE4B upregulation. In addition, circNCOA4 was packaged into exosomes and showed potential diagnostic value for acute ischemic stroke (AIS) patients. CircNCOA4 has potential diagnostic value for AIS patients and promoted OGD-induced neuron injury via the miR-338-5p/PDE4B axis, providing a new insight into the pathology of AIS.

miR-100-5p activation of the autophagy response through inhibiting the mTOR pathway and suppression of cerebral infarction progression in mice

In recent years, the association between microRNAs (miRNAs) and autophagy in cerebral infarction (CI) has attracted increasingly more attention. The mammalian target of the rapamycin (mTOR) pathway is a key protein regulating the autophagy response. miR-100-5p can bind to the mTOR protein, but its role in CI remains unclear yet. This experiment aims to clarify the role of miR-100-5p in CI. Bioinformatics analysis was performed to screen differentiated expressed functional genes between CI tissue and normal tissue specimens. In vivo experiments: the mouse model of CI was established by middle cerebral artery occlusion (MCAO) methods, After being treated with miR-100-5p-overexpressing lentivirus, the amount of terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL)-positive fluorescence and the fluorescent expression level of mTOR protein were significantly inhibited in the CI region. Western blotting analysis showed that miR-100-5p inhibited the protein expression level of phosphorylated mTOR and total mTOR and enhanced the expression of autophagy-related proteins Beclin, microtubule-associated protein light chain 3II (LC-3II), and autophagy-related gene 7 (ATG-7). For in vitro experiment, after the BV-2 cells were successfully infected with the control lentivirus and miR-100-5p-overexpression lentivirus, they were stimulated with 1% hypoxia and low-glucose medium in a tri-gas incubator for 24 h. It was found that miR-100-5p could significantly lower the protein expression level of phosphorylated mTOR and total mTOR, and increase the expression of the Beclin, LC-3II, ATG-7 autophagy related proteins. miR-100-5p promotes the autophagy response through binding to mTOR protein, thereby inhibiting apoptosis and delaying the progression of CI.

CircHECTD1 promoted MIRI-associated inflammation via inhibiting miR-138-5p and upregulating ROCK2

Myocardial ischemia-reperfusion injury (MIRI) was often observed after surgeries, causing a lot of suffering to patients. Inflammation and apoptosis were critical determinants during MIRI. We conveyed experiments to reveal the regulatory functions of circHECTD1 in MIRI development. The Rat MIRI model was established and determined by 2,3,5-triphenyl tetrazolium chloride (TTC) staining. We analyzed cell apoptosis using TUNEL and flow cytometry. Proteins expression was evaluated by western blot. The RNA level was determined by qRT-PCR. Secreted inflammatory factors were analyzed by ELISA assay. To predict the interaction sequences on circHECTD1, miR-138-5p, and ROCK2, bioinformatics analysis was performed. Dual-luciferase assay was used to confirm these interaction sequences. CircHECTD1 and ROCK2 were upregulated in the rat MIRI model, while miR-138-5p was decreased. CircHECTD1 knockdown alleviated H/R-induced inflammation in H9c2 cells. Direct interaction and regulation of circHECTD1/miR-138-5p and miR-138-5p/ROCK2 were confirmed by dual-luciferase assay. CircHECTD1 promoted H/R-induced inflammation and cell apoptosis by inhibiting miR-138-5p. miR-138-5p alleviated H/R-induced inflammation, while ectopic ROCK2 antagonized such effect of miR-138-5p. Our research suggested that the circHECTD1-modulated miR-138-5p suppressing is responsible for ROCK2 activation during H/R-induced inflammatory response, providing a novel insight into MIRI-associated inflammation.

An update on the molecular mechanism and pharmacological interventions for Ischemia-reperfusion injury by regulating AMPK/mTOR signaling pathway in autophagy

AMP-activated protein kinase (5'-adenosine monophosphate-activated protein kinase, AMPK)/mammalian target of rapamycin (mTOR) is an important signaling pathway maintaining normal cell function and homeostasis in vivo. The AMPK/mTOR pathway regulates cellular proliferation, autophagy, and apoptosis. Ischemia-reperfusion injury (IRI) is secondary damage that frequently occurs clinically in various disease processes and treatments, and the exacerbated injury during tissue reperfusion increases disease-associated morbidity and mortality. IRI arises from multiple complex pathological mechanisms, among which cell autophagy is a focus of recent research and a new therapeutic target. The activation of AMPK/mTOR signaling in IRI can modulate cellular metabolism and regulate cell proliferation and immune cell differentiation by adjusting gene transcription and protein synthesis. Thus, the AMPK/mTOR signaling pathway has been intensively investigated in studies focused on IRI prevention and treatment. In recent years, AMPK/mTOR pathway-mediated autophagy has been found to play a crucial role in IRI treatment. This article aims to elaborate the action mechanisms of AMPK/mTOR signaling pathway activation in IRI and summarize the progress of AMPK/mTOR-mediated autophagy research in the field of IRI therapy.

miR-338-5p Levels and Cigarette Smoking are Associated With Neuropathic Pain Severity in Individuals With Spinal Cord Injury: Preliminary Findings From a Genome-Wide microRNA Expression Profiling Screen

OBJECTIVE

To identify microRNA biomarkers and clinical factors associated with neuropathic pain after spinal cord injury.

DESIGN

Cross-sectional, secondary analysis of baseline data collected from ongoing clinical studies. Using a genome-wide microRNA screening approach, we studied differential microRNA expression in serum from 43 adults with spinal cord injury enrolled in ongoing clinical studies. Least squares regression was used to identify associations between microRNA expression, clinical factors, and neuropathic pain severity.

SETTING

Community-dwelling individuals with spinal cord injury.

PARTICIPANTS

Participants (N=43) were at least 18 years old with spinal cord injury, with 28 reporting neuropathic pain and 15 reporting no neuropathic pain.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Pain presence, type, and intensity were assessed with the International Spinal Cord Injury Pain Basic Data Set. Serum microRNA normalized deep sequencing counts were quantified from blood samples. Participant demographic factors, injury characteristics, medication use, and health habits were collected via questionnaire.

RESULTS

miR-338-5p expression and history of cigarette smoking were associated with and explained 37% of the variance in neuropathic pain severity (R2=0.37, F2,18=5.31, P=.02) independent of other clinical factors. No association was identified between miR-338-5p levels and nociceptive pain severity.

CONCLUSIONS

Our findings suggest that miR-338-5p and cigarette smoking may both play a role in the development or maintenance of neuropathic pain after spinal cord injury. While additional work is needed to confirm these findings, validated target analysis suggests a neuroprotective role of miR-338-5p in modulating neuroinflammation and neuronal apoptosis and that its downregulation may result in maladaptive neuroplastic mechanisms contributing to neuropathic pain after spinal cord injury.

Long non-coding RNA TUG1 knockdown prevents neurons from death to alleviate acute spinal cord injury via the microRNA-338/BIK axis

Taurine up-regulated gene 1 (TUG1) is a cancer-associated long noncoding RNA (lncRNA) and engages in the development of spinal cord injury (SCI), a suffering neuropathological disorder. However, the regulatory role of TUG1 in acute SCI (ASCI) is still underdetermined. RT-qPCR and western blot analysis were applied to measure the expression of TUG1, microRNA-338 (miR-338), Bcl2-interacting killer (BIK), cleaved caspase 3 (c-caspase 3) and hypoxia-inducible factor-1 alpha (HIF-1α) in ASCI rats and hypoxic cells. Cell death was evaluated using flow cytometric analysis. The relationships among miR-338, TUG1 or BIK were confirmed by luciferase reporter assay, RNA immunoprecipitation and RNA pull-down. Accordingly, we monitored higher expression of TUG1 and BIK, but lower expression of miR-338 in ASCI rats and hypoxic cells. In vitro, hypoxia expedited cell death and c-caspase 3 levels. In vivo, ASCI rats were successfully developed as evidenced by diminished Basso-Beattie-Bresnahan (BBB) locomotor score and enhanced c-caspase 3 and HIF-1α expression. Nevertheless, TUG1 knockdown mitigated the cell death in ASCI rats and hypoxic cells. Mechanically, TUG1 interacted with miR-338 to regulate the BIK expression. Together, TUG1 silencing could alleviate the death in neurons and ASCI models via modulating the miR-338/BIK axis.

Inhibition of Long Noncoding RNA SNHG15 Ameliorates Hypoxia/Ischemia-Induced Neuronal Damage by Regulating miR-302a-3p/STAT1/NF-κB Axis

PURPOSE

Ischemic brain injury results in high mortality and serious neurologic morbidity. Here, we explored the role of SNHG15 in modulating neuronal damage and microglial inflammation after ischemia stroke.

MATERIALS AND METHODS

The hypoxia/ischemia models were induced by middle cerebral artery occlusion in mice and oxygen-glucose deprivation/reoxygenation (OGD/R) in vitro. Quantitative real-time PCR (qRT-PCR) and Western blot were conducted to determine the levels of SNHG15, miR-302a-3p, and STAT1/NF-κB. Moreover, gain- or loss-of functional assays of SNHG15 and miR-302a-3p were conducted. MTT assay was used to evaluate the viability of HT22 cells, and the apoptotic level was determined by flow cytometry. Furthermore, enzyme-linked immunosorbent assay was performed to detect oxidative stress and inflammatory mediators in the ischemia cortex and OGD/R-treated BV2 microglia.

RESULTS

The SNHG15 and STAT1/NF-κB pathways were both distinctly up-regulated, while miR-302a-3p was notably down-regulated in the ischemia cortex. Additionally, overexpressing SNHG15 dramatically enhanced OGD/R-mediated neuronal apoptosis as well as the expression of oxidative stress and inflammation factors from microglia. In contrast, knocking down SNHG15 or overexpressing miR-302a-3p relieved OGD/R-mediated neuronal apoptosis and microglial activation. Moreover, the rescue experiment testified that overexpressing miR-302a-3p also attenuated SNHG15 up-regulation-induced effects. In terms of the mechanisms, SNHG15 sponged miR-302a-3p and activated STAT1/NF-κB as a competitive endogenous RNA, while miR-302a-3p targeted STAT1 and negatively regulated the STAT1/NF-κB pathway.

CONCLUSION

SNHG15 was up-regulated in the hypoxia/ischemia mouse or cell model. The inhibition of SNHG15 ameliorates ischemia/hypoxia-induced neuronal damage and microglial inflammation by regulating the miR-302a-3p/STAT1/NF-κB pathway.

Knockdown of long non-coding RNA RMRP protects cerebral ischemia-reperfusion injury via the microRNA-613/ATG3 axis and the JAK2/STAT3 pathway

Cerebral ischemia-reperfusion (I/R) injury can induce the mitophagy of neurons in the ischemic brain. Long non-coding RNAs (lncRNAs) play an important role in the pathogenesis of various injuries, especially in cerebral I/R injury. The purpose of this study is to investigate the molecular mechanism of lncRNA RNA component of mitochondrial RNA processing endoribonuclease (RMRP) in cerebral I/R injury. The middle cerebral artery occlusion (MCAO) mouse model was established. Neurological deficit score, pathological structure, infarcted area, neuron number, cell apoptosis, and coagulation ability of MCAO mice were evaluated. The expressions of RMRP, microRNA (miR)-613, and ATG3 in MCAO mice were detected. The binding relationships among miR-613, RMRP, and ATG3 were predicted and verified. Neuro 2A (N2a) cells were treated with oxygen-glucose deprivation/reperfusion (OGD/R) to simulate I/R injury. Cell viability and apoptosis assays were performed. The effects of miR-613, ATG3, and RMRP on I/R injury were verified by functional rescue experiments. JAK2/STAT3 phosphorylation level was detected. We found significantly upregulated RMRP and ATG3, and downregulated miR-613 expressions in MCAO mice. RMRP could escalate ATG3 mRNA expression through miR-613. RMRP knockdown promoted viability and inhibited apoptosis of OGD/R-treated N2a cells, which could be reversed by miR-613 inhibition or ATG3 overexpression. RMRP overexpression inhibited the activation of JAK2/STAT3 signaling pathway. We demonstrated that lncRNA RMRP competitively bound to miR-613, leading to the increase of ATG3 expression and the inhibition the JAK2/STAT3 pathway, thus promoting cerebral I/R injury in mice.

LncRNA GAS5 Silencing Attenuates Oxygen-Glucose Deprivation/Reperfusion-Induced Injury in Brain Microvascular Endothelial Cells via miR-34b-3p-Dependent Regulation of EPHA4

BACKGROUND

The aim of our study was to explore the role of long non-coding RNA (lncRNA) growth arrest-specific 5 (GAS5) in ischemic stroke using oxygen-glucose deprivation/reperfusion (OGD/R)-induced bEnd.3 cells as in vitro cell model.

METHODS

Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot assay were adopted to analyze RNA and protein expression. Cell viability and apoptosis were analyzed by Cell Counting Kit-8 (CCK8) assay and flow cytometry. The levels of nitric oxide (NO) and endothelin-1 (ET-1) in culture supernatant were examined by their matching commercial kits. The intermolecular target interaction was predicted by starBase software and tested by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay.

RESULTS

OGD/R-induced apoptosis and dysregulation in vascular endocrine system were largely alleviated by the knockdown of GAS5. GAS5 interacted with microRNA-34b-3p (miR-34b-3p), and GAS5 silencing protected bEnd.3 cells from OGD/R-induced injury partly through up-regulating miR-34b-3p. EPH receptor A4 (EPHA4) was a target of miR-34b-3p. GAS5 acted as the molecular sponge of miR-34b-3p to up-regulate EPHA4 in bEnd.3 cells. GAS5 interference protected against OGD/R-induced damage in bEnd.3 cells partly through down-regulating EPHA4.

CONCLUSION

LncRNA GAS5 knockdown protected brain microvascular endothelial cells bEnd.3 from OGD/R-induced injury depending on the regulation of miR-34b-3p/EPHA4 axis.

MiR-410-3p overexpression ameliorates neurological deficits in rats with hypoxic-ischemic brain damage

Neonatal hypoxic-ischemic encephalopathy (HIE) is major cause of neonatal death or long-term neurodevelopmental disabilities, which becomes a major practical problem currently in clinic. Whereas, its pathophysiology and underlying molecular mechanism is not clear. MicroRNAs are involved in the normal growth and development of neuronal cells. Herein, the objective of this research was to examine the roles of miR-410-3p in neurological deficits, neuronal injury and neuron apoptosis after hypoxic-ischemic and to explore its associated mechanisms. We established the hypoxic-ischemic brain damage (HIBD) model and oxygen glucose deprivation (OGD) model. Zea-longa score and TTC staining were used to detect the acute cerebral dysfunction after HIBD. QPCR verification exhibited notable downregulation of miR-410-3p expression at 24 h in rats after HIBD as well as that in PC12, SY5Y cells and primary cortical neurons post OGD. To further determine the function of miR-410-3p, lentivirus-mediated overexpression virus was applied in vivo and in vitro. Behavioral tests, including Morris water maze, open field test, Y maze test, neurological severity score and rotating rod test, were performed to evaluate long-term behavioral changes of rats at 1 month post HIBD. The results showed that the number of cells together with the axonal length were reduced post OGD. While the increase of cells number and the axonal length was measured after upregulating miR-410-3p. Meanwhile, miR-410-3p overexpression inhibited neuron apoptosis and enhanced neuronal survival. In addition, long-term motor and cognitive functions were remarkably recovered in HIBD rats with miR-410-3p overexpression. Together, miR-410-3p exerts a critical role in protecting neuronal growth as well as promoting motor and cognitive function recovery in neonatal rats subjected to HIBD. The current study therefore provides critical insights to develop the activator of miR-410-3p for the clinical treatment of HIBD in future clinic trial.