LncRNA H19 promotes inflammatory response induced by cerebral ischemia-reperfusion injury through regulating the miR-138-5p-p65 axis

Molecular mechanism of HDAC6-mediated pyroptosis in neurological function recovery after cardiopulmonary resuscitation in rats

Brain injury after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) is the leading cause of neurological dysfunction and death. This study aimed to explore the mechanism of histone deacetylase 6 (HDAC6) in neurofunctional recovery following CA/CPR in rats. A rat model was established by CA/CPR treatment. Adenovirus-packaged sh-HDAC6 was injected into the tail vein. To evaluate the neurofunction of rats, survival time, neurofunctional scores, serum NSE/S100B, and brain water content were measured and Morris water maze test was performed. HDAC6, microRNA (miR)-138-5p, Nod-like receptor protein 3 (NLRP3), and pyroptotic factors levels were determined by real-time quantitative polymerase chain reaction or Western blot assay. HDAC6 and H3K9ac enrichment on miR-138-5p promoter were examined by chromatin immunoprecipitation. miR-138-5p-NLRP3 binding was analyzed by dual-luciferase reporter assay. NLRP3 inflammasome was activated with nigericin sodium salt. After CPR treatment, HDAC6 was highly expressed, while miR-138-5p was downregulated. HDAC6 downregulation improved neurofunction and reduced pyroptosis. HDAC6 enrichment on the miR-138-5p promoter deacetylated H3K9ac, inhibiting miR-138-5p, and promoting NLRP3-mediated pyroptosis. Downregulating miR-138-5p partially reversed the protective effect of HDAC6 inhibition after CPR. In Conclusion, HDAC6 enrichment on miR-138-5p promoter deacetylated H3K9ac, inhibiting miR-138-5p expression and promoting NLRP3-mediated pyroptosis, worsening neurological dysfunction in rats after CPR.

Temporal expression profiles of microRNAs associated with acute phase of brain ischemia in gerbil hippocampus

Neuroprotective therapeutic potential for restoring dysregulated microRNA (miRNA) expression has previously been demonstrated in a gerbil cerebral infarction model. However, since temporal changes in miRNA expression profiles following stroke onset are unknown, miRNAs proving to be useful therapeutic targets have yet to be identified. We evaluated cognitive function, hippocampal neuronal cell death, and microarray-based miRNA expression profiles at 5, 9, 18, 36, and 72 h after 5-min whole brain ischemia in gerbils. A decline in cognitive function occurred in parallel with increased neuronal cell death 36-72 h after ischemia. The Jonckheere-Terpstra test was used to analyze miRNA expression trends 5-72 h after ischemia. The expression levels of 63 miRNAs were significantly upregulated, whereas 32 miRNAs were significantly downregulated, monotonically. Of the 32 monotonically downregulated miRNAs, 18 showed the largest decrease in expression 5-9 h after ischemia. A subset of these dysregulated miRNAs (miR-378a-5p, miR-204-5p, miR-34c-5p, miR-211-5p, miR-34b-3p, and miR-199b-3p) could be associated with brain ischemia and neuropsychiatric disorders.

Exploring Circulating Long Non-Coding RNAs in Mild Cognitive Impairment Patients' Blood

Mild cognitive impairment (MCI) is a transitional clinical stage prior to dementia. Patients with amnestic MCI have a high risk of progression toward Alzheimer's disease. Both amnestic mild cognitive impairment and sporadic Alzheimer's disease are multifactorial disorders consequential from a multifaceted cross-talk among molecular and biological processes. Non-coding RNAs play an important role in the regulation of gene expression, mainly long non-coding RNAs (lncRNAs), that regulate other RNA transcripts through binding microRNAs. Cross-talk between RNAs, including coding RNAs and non-coding RNAs, produces a significant regulatory network all through the transcriptome. The relationship of genes and non-coding RNAs could improve the knowledge of the genetic factors contributing to the predisposition and pathophysiology of MCI. The objective of this study was to identify the expression patterns and relevant lncRNA-associated miRNA regulatory axes in the blood of MCI patients, which includes lncRNA-SNHG16, lncRNA-H19, and lncRNA-NEAT1. Microarray investigations have demonstrated modifications in the expression of long non-coding RNAs (lncRNA) in the blood of patients with MCI compared with control samples. This is the first study to explore lncRNA profiles in mild cognitive impairment blood. Our study proposes RNAs targets involved in molecular pathways connected to the pathogenesis of MCI.

Are Ischemic Stroke and Alzheimer's Disease Genetically Consecutive Pathologies?

Complex diseases that affect the functioning of the central nervous system pose a major problem for modern society. Among these, ischemic stroke (IS) holds a special place as one of the most common causes of disability and mortality worldwide. Furthermore, Alzheimer's disease (AD) ranks first among neurodegenerative diseases, drastically reducing brain activity and overall life quality and duration. Recent studies have shown that AD and IS share several common risk and pathogenic factors, such as an overlapping genomic architecture and molecular signature. In this review, we will summarize the genomics and RNA biology studies of IS and AD, discussing the interconnected nature of these pathologies. Additionally, we highlight specific genomic points and RNA molecules that can serve as potential tools in predicting the risks of diseases and developing effective therapies in the future.

Thermos-responsive hydrogel system encapsulated engineered exosomes attenuate inflammation and oxidative damage in acute spinal cord injury

Introduction: Spinal cord injury (SCI) is a serious and disabling condition, and the effectiveness of conventional treatment is limited, such as supportive treatment and emergency surgery. Exosomes derived from umbilical cord mesenchymal stem cells (UCMSC-Exos) have potential therapeutic effects on SCI but are limited by delivery efficiency. Our study aimed to further investigate the therapeutic effects of miR-138-modified UCMSC-exosomes (Exos-138) following SCI. Methods: We developed an injectable triblock polymer of polyglycolic acid copolymer and polyethylene glycol (PLGA-PEG-PLGA)-loaded temperature-sensitive hydrogel of miR-138-modified stem cell exosomes and characterised its biocompatibility in vitro. In Sprague-Dawley rats with SCI, the hydrogel was injected into the injury site, behavioural scores were measured, and pathological analysis was conducted postoperatively to assess neurological recovery. Results: In vitro, our data demonstrated that miR-138-5p-modified UCMSC-Exos can reduce inflammation levels in BV-2 cells through the NLRP3-caspase1 signalling pathway and reduce neuronal apoptosis by downregulating intracellular reactive oxygen species levels through the Nrf2-keap1 signalling cascade. The results of in vivo experiments showed that the P-Exos-138 hydrogel promoted neurological recovery in rats with SCI. Discussion: Our study explored a novel exosome delivery system that can be a potential therapeutic strategy for SCI. Our study, currently, has theoretical value; however, it can serve as a basis for further investigations on the treatment approaches at various stages of SCI development in inflammation-dependent injury of the central nervous system.

Catalpol Mitigates Alzheimer's Disease Progression by Promoting the Expression of Neural Stem Cell Exosomes Released miR-138-5p

Alzheimer's disease (Alzheimer's disease, AD) is a neurodegenerative disease characterized by senile plaque deposition and neurofibrillary tangles. The pathogenesis of AD is complicated and the drugs used to treat AD are single-targeted drugs, which can only improve or alleviate the symptoms of patients, but cannot delay or prevent the progress of the disease. Because of its ability to act on multiple targets, multiple systems, multiple links, and multiple pathways, Chinese herbal compound prescriptions have shown unique advantages in the research and treatment of AD. Our previous study has demonstrated the protect role of the Chinese medicine Rehmannia in AD. However, the underlying mechanism remains unclear. In the present study, both in vitro and vivo experiments were employed, and we found Catalpol (Ca), the main extract of Rehmannia, could mitigate AD progression both in vitro and in vivo by promoting miR-138-5p level in neural stem cell secreted exosomes.

Non-coding RNAs in stroke pathology, diagnostics, and therapeutics

Ischemic stroke is a leading cause of death and disability worldwide. Methods to alleviate functional deficits after ischemic stroke focus on restoration of cerebral blood flow to the affected area. However, pharmacological or surgical methods such as thrombolysis and thrombectomy have a narrow effective window. Harnessing and manipulating neurochemical processes of recovery may provide an alternative to these methods. Recently, non-coding RNA (ncRNA) have been increasingly investigated for their contributions to the pathology of diseases and potential for diagnostic and therapeutic applications. Here we will review several ncRNA - H19, MALAT1, ANRIL, NEAT1, pseudogenes, small nucleolar RNA, piwi-interacting RNA and circular RNA - and their involvement in stroke pathology. We also examine these ncRNA as potential diagnostic biomarkers, particularly in circulating blood, and as targets for therapeutic interventions. An important aspect of this is a discussion of potential methods of treatment delivery to allow for targeting of interventions past the blood-brain barrier, including lipid nanoparticles, polymer nanoparticles, and viral and non-viral vectors. Overall, several long non-coding RNA (lncRNA) discussed here have strong implications for the development of pathology and functional recovery after ischemic stroke. LncRNAs H19 and ANRIL show potential as diagnostic biomarkers, while H19 and MALAT1 may prove to be effective therapeutics for both minimising damage as well as promoting recovery. Other ncRNA have also been implicated in ischemic stroke but are currently too poorly understood to make inferences for diagnosis or treatment. Whilst the field of ncRNAs is relatively new, significant work has already highlighted that ncRNAs represent a promising novel investigative tool for understanding stroke pathology, could be used as diagnostic biomarkers, and as targets for therapeutic interventions.

Methionine Restriction Improves Cognitive Ability by Alleviating Hippocampal Neuronal Apoptosis through H19 in Middle-Aged Insulin-Resistant Mice

LncRNA H19 has been reported to regulate apoptosis and neurological diseases. Hippocampal neuron apoptosis damages cognitive ability. Methionine restriction (MR) can improve cognitive impairment. However, the effect of MR on hippocampal neuronal apoptosis induced by a high-fat diet (HFD) in middle-aged mice remains unclear. For 25 weeks, middle-aged mice (C57BL/6J) were given a control diet (CON, 0.86% methionine + 4.2% fat), a high-fat diet (HFD, 0.86% methionine + 24% fat), or an HFD + MR diet (HFMR, 0.17% methionine + 24% fat). The HT22 cells were used to establish the early apoptosis model induced by high glucose (HG). In vitro, the results showed that MR significantly improved cell viability, suppressed the generation of ROS, and rescued HT22 cell apoptosis in a gradient-dependent manner. In Vivo, MR inhibited the damage and apoptosis of hippocampal neurons caused by a high-fat diet, reduced hippocampal oxidative stress, improved hippocampal glucose metabolism, relieved insulin resistance, and enhanced cognitive ability. Furthermore, MR could inhibit the overexpression of H19 and caspase-3 induced by HFD, HG, or H2O2 in vivo and in vitro, and promoted let-7a, b, e expression. These results indicate that MR can protect neurons from HFD-, HG-, or H2O2-induced injury and apoptosis by inhibiting H19.

MicroRNA-138-5p Targets Pro-Apoptotic Factors and Favors Neural Cell Survival: Analysis in the Injured Spinal Cord

The central nervous system microRNA miR-138-5p has attracted much attention in cancer research because it inhibits pro-apoptotic genes including CASP3. We hypothesize that miR-138-5p downregulation after SCI leads to overexpression of pro-apoptotic genes, sensitizing neural cells to noxious stimuli. This study aimed to identify miR-138-5p targets among pro-apoptotic genes overexpressed following SCI and to confirm that miR-138-5p modulates cell death in neural cells. Gene expression and histological analyses revealed that the drop in miR-138-5p expression after SCI is due to the massive loss of neurons and oligodendrocytes and its downregulation in neurons. Computational analyses identified 176 potential targets of miR-138-5p becoming dysregulated after SCI, including apoptotic proteins CASP-3 and CASP-7, and BAK. Reporter, RT-qPCR, and immunoblot assays in neural cell cultures confirmed that miR-138-5p targets their 3′UTRs, reduces their expression and the enzymatic activity of CASP-3 and CASP-7, and protects cells from apoptotic stimuli. Subsequent RT-qPCR and histological analyses in a rat model of SCI revealed that miR-138-5p downregulation correlates with the overexpression of its pro-apoptotic targets. Our results suggest that the downregulation of miR-138-5p after SCI may have deleterious effects on neural cells, particularly on spinal neurons.

An update on the functional roles of long non‑coding RNAs in ischemic injury (Review)

Ischemic injuries result from ischemia and hypoxia in cells. Tissues and organs receive an insufficient supply of nutrients and accumulate metabolic waste, which leads to the development of inflammation, fibrosis and a series of other issues. Ischemic injuries in the brain, heart, kidneys, lungs and other organs can cause severe adverse effects. Acute renal ischemia induces acute renal failure, heart ischemia induces myocardial infarction and cerebral ischemia induces cerebrovascular accidents, leading to loss of movement, consciousness and possibly, life-threatening disabilities. Existing evidence suggests that long non-coding RNAs (lncRNAs) are regulatory sequences involved in transcription, post-transcription, epigenetic regulation and multiple physiological processes. lncRNAs have been shown to be differentially expressed following ischemic injury, with the severity of the ischemic injury being affected by the upregulation or downregulation of certain types of lncRNA. The present review article provides an extensive summary of the functional roles of lncRNAs in ischemic injury, with a focus on the brain, heart, kidneys and lungs. The present review mainly summarizes the functional roles of lncRNA MALAT1, lncRNA MEG3, lncRNA H19, lncRNA TUG1, lncRNA NEAT1, lncRNA AK139328 and lncRNA CAREL, among which lncRNA MALAT1, in particular, plays a crucial role in ischemic injury and is currently a hot research topic.

Long Non-coding RNA H19 Deteriorates Hypoxic-Ischemic Brain Damage by Interacting with MicroRNA-140-5p and STAT3

OBJECTIVE

Even though extensive studies have surveyed long non-coding RNA (lncRNA)-related networks in hypoxic-ischemic brain damage (HIBD), the concrete function of lncRNA H19 (H19) in HIBD is still in ambiguity. Therein, this work intends to decipher H19-related network of microRNA (miR)-140-5p and signal transducer and activator of transcription 3 (STAT3) in HIBD.

METHODS

Brain microvascular endothelial cells (BMECs) from BALB/c mice were isolated and induced by oxygen glucose deprivation (OGD). OGD-induced BMECs were transfected with depleted or restored H19, miR-140-5p or STAT3, and cell apoptosis, migration and angiogenesis were examined. H19, miR-140-5p and STAT3 expression and their internal connections were tested.

RESULTS

H19 and STAT3 were overexpressed while miR-140-5p was down-regulated in OGD-induced BMECs. H19 or STAT3 knockdown, or miR-140-5p restoration repressed apoptosis and improved migration and angiogenesis of OGD-induced BMECs. MiR-140-5p restoration negated the impacts of up-regulated H19 on OGD-induced BMECs. H19 bound to miR-140-5p to modulate STAT3 expression.

CONCLUSION

The work illustrates that depleting H19 or STAT3 or restoring miR-140-5p attenuates HIBD and supplies a novel perspective for HIBD management.

Integrated Analysis of Competitive Endogenous RNA Networks in Acute Ischemic Stroke

Background: Acute ischemic stroke (AIS) is a severe neurological disease with complex pathophysiology, resulting in the disability and death. The goal of this study is to explore the underlying molecular mechanisms of AIS and search for new potential biomarkers and therapeutic targets.

Methods: Integrative analysis of mRNA and miRNA profiles downloaded from Gene Expression Omnibus (GEO) was performed. We explored differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMirs) after AIS. Target mRNAs of DEMirs and target miRNAs of DEGs were predicted with target prediction tools, and the intersections between DEGs and target genes were determined. Subsequently, Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses, Gene set enrichment analysis (GSEA), Gene set variation analysis (GSVA), competitive endogenous RNA (ceRNA) (lncRNA-miRNA-mRNA) network, protein–protein interaction (PPI) network, and gene transcription factors (TFs) network analyses were performed to identify hub genes and associated pathways. Furthermore, we obtained AIS samples with evaluation of immune cell infiltration and used CIBERSORT to determine the relationship between the expression of hub genes and infiltrating immune cells. Finally, we used the Genomics of Drug Sensitivity in Cancer (GDSC) database to predict the effect of the identified targets on drug sensitivity.

Result: We identified 293 DEGs and 26 DEMirs associated with AIS. DEGs were found to be mainly enriched in inflammation and immune-related signaling pathways through enrichment analysis. The ceRNA network included nine lncRNAs, 13 miRNAs, and 21 mRNAs. We used the criterion AUC >0.8, to screen a 3-gene signature (FBL, RPS3, and RPS15) and the aberrantly expressed miRNAs (hsa-miR-125a-5p, hsa-miR-125b-5p, hsa-miR-148b-3p, and hsa-miR-143-3p) in AIS, which were verified by a method of quantitative PCR (qPCR) in HT22 cells. T cells CD8, B cells naïve, and activated NK cells had statistical increased in number compared with the acute cerebral infarction group. By predicting the IC50 of the patient to the drug, AZD0530, Z.LLNle.CHO and NSC-87877 with significant differences between the groups were screened out. AIS demonstrated heterogeneity in immune infiltrates that correlated with the occurrence and development of diseases.

Conclusion: These findings may contribute to a better understanding of the molecular mechanisms of AIS and provide the basis for the development of novel treatment targets in AIS.

H19 is involved in the regulation of inflammatory responses in acute gouty arthritis by targeting miR-2-3p

A great number of studies have confirmed that long noncoding RNA (lncRNA) are involved in the regulation of inflammatory response in acute gouty arthritis (AGA). This paper aimed to survey the regulatory mechanism of H19 on AGA. The expression of serum H19 in all subjects was examined by qRT-PCR. The ROC curve was used to estimate the diagnostic value of H19 for AGA. THP-1 cells were induced by MSU to establish in vitro AGA cell model. The concentrations of cytokines such as IL-1β, IL-8, and TNF-α were tested by ELISA. Luciferase reporter gene analysis was used to verify the interaction between H19 and the 3'-UTR of miR-22-3p. Expressions of serum H19 in AGA patients were significantly higher than that in controls. The ROC curve indicated the potential of H19 as a diagnostic marker for AGA. Cell experiments revealed that the downregulation of H19 significantly inhibited the expressions of IL-1β, IL-8, and TNF-α. The luciferase reporter gene assay manifested that miR-22-3p is the target gene of H19. And knockdown of miR-22-3p overturned the downregulation of inflammatory factors caused by H19 inhibition. H19 aggravated MSU-induced THP-1 inflammation by negatively targeting miR-22-3p, suggesting a new regulatory mechanism and potential therapeutic target for AGA.

Long noncoding RNA H19 mediates neural stem/progenitor cells proliferation, differentiation and apoptosis through the p53 signaling pathway after ischemic stroke

Long non-coding RNA (LncRNA) H19 plays an important role on the biological functions of endogenous neural stem/progenitor cells (NSPCs). Our study aimed to explore the functions of H19 in NSPCs induced by oxygen-glucose deprivation/reperfusion (OGD/R) in vitro and the underlying mechanisms. In this study, our results showed that knockdown of H19 significantly inhibited NSPCs proliferation. Additionally, the apoptosis of NSPCs after ODG/R injury was notably promoted by H19 knockdown. Cell cycle arrest was induced in NSPCs at G0/G1 phase after OGD/R, while knockdown of H19 decreased the percentage of cells at G2/S phase. The results of immunofluorescence analysis revealed that H19 knockdown reduced the staining intensity of Ki-67 and DCX. Furthermore, H19 knockdown enhanced the expression of p53, Bax and Cleaved Caspase-3, while Bcl-2 expression was decreased. Silencing of H19 suppressed the NSPCs proliferation, cell cycle progression and differentiation, whereas cell apoptosis was promoted. Upregulation of H19 abolished OGD/R-induced NSPCs apoptosis, while cell proliferation and differentiation were promoted. Furthermore, the effects of overexpressed H19 on NSPCs proliferation, differentiation and apoptosis were abrogated by the upregulation of p53. In summary, overexpressed H19 resulted in the inactivation of p53, which promoted NSPCs proliferation, differentiation, and inhibited cell apoptosis. These findings suggested that H19 could promote cell proliferation and differentiation after OGD/R through suppressing the p53 signaling.

Long Non-Coding RNA-Mediated Competing Endogenous RNA Networks in Ischemic Stroke: Molecular Mechanisms, Therapeutic Implications, and Challenges

Ischemic stroke (IS) is a disease that is characterized by high mortality and disability. Recent studies have shown that LncRNA-mediated competing endogenous RNA (ceRNA) networks play roles in the occurrence and development of cerebral I/R injury by regulating different signaling pathways. However, no systematic analysis of ceRNA mechanisms in IS has been reported. In this review, we discuss molecular mechanisms of LncRNA-mediated ceRNA networks under I/R injury. The expression levels of LncRNAs, microRNAs (miRNAs), and messenger RNAs (mRNAs) and their effects in four major cell types of the neurovascular unit (NVU) are also involved. We further summarize studies of LncRNAs as biomarkers and therapeutic targets. Finally, we analyze the advantages and limitations of using LncRNAs as therapeutics for IS.

Exosomes derived from mesenchyml stem cells ameliorate oxygen-glucose deprivation/reoxygenation-induced neuronal injury via transferring MicroRNA-194 and targeting Bach1

The neuroprotective function of miR-194 on neurovascular endothelial cell injury is perceived as a novel method for clinical therapy. So are exosomes (EXs), being attractive in neurofunctional recovery. However, whether EXs derived from mesenchymal stromal cells (MSCs) perform the same efficacy by transferring miR-194 and the underlying mechanism remain vague. This study rooted in oxygen-glucose deprivation/reoxygenation (OGD/R) model. MSCs were isolated by gradient centrifugation and identified by flow cytometry. EXs were obtained through ultracentrifugation, whereas protein levels of specific markers (CD63, TGS101), together with Bach1, Nrf2 and HO-1 were measured by western blot. The relative mRNA expressions of Bach1, NOX1, AGSL4, GPX4 and miR-194 were measured by RT-qPCR assays. Cell viability was measured by cell counting kit-8, and cell migration was detected by wound healing assay. The interaction between miR-194 and Bach1 was predicted by starBase and confirmed by dual luciferase reporter assay. OGD/R dampened cell viability and miR-194 expression. Bach1 could bind with miR-194. miR-194 mimic attenuated the effect of OGD/R on cell viability and protein levels of Nrf2, HO-1 and Bach1, whereas Bach1 overexpression reversed the effect of miR-194 mimics. MSC-EXs could merge with HBMECs. Based on this, MSC-EXs loaded with miR-194 downregulated Bach1 protein level and iron content and the mRNA expressions of NOX1 and ACSL4, yet upregulated miR-194 and GPX4 expressions and Nrf2/HO-1 protein level in OGD/R-injured cells, whereas those carrying ShmiR-194 had the opposite effects. Our study suggested MSC-EXs loaded with miR-194 attenuated OGD/R-induced injury via targeting Bach1, providing a new therapeutic strategy for cerebral injuries.

Silencing of H19 alleviates oxygen-glucose deprivation/reoxygenation-triggered injury through the regulation of the miR-1306-5p/BCL2L13 axis

Cerebral ischemia/reperfusion (I/R) injury remains a leading cause of death and disability. Long noncoding RNAs (lncRNAs) exert key functions in cerebral I/R injury. Here, we sought to elucidate the mechanism underlying the regulation of H19 in cerebral I/R cell injury. An in vitro model of cerebral I/R injury was created using oxygen-glucose deprivation/reoxygenation (OGD/R). The levels of H19, miR-1306-5p and B cell lymphoma-2 (Bcl-2)-like 13 (BCL2L13) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Cell viability and apoptosis were determined by the Cell Counting-8 Kit (CCK-8) assay and flow cytometry, respectively. The levels of lactate dehydrogenase (LDH) and cytokines were evaluated by enzyme-linked immunosorbent assays (ELISA). Direct relationships among H19, miR-1306-5p and BCL2L13 were verified by dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pulldown assays. Our data showed that H19 and BCL2L13 were highly expressed in the cerebral I/R injury rats and OGD/R-triggered SK-N-SH and IMR-32 cells. The knockdown of H19 or BLC2L13 alleviated OGD/R-triggered injury in SK-N-SH and IMR-32 cells. Moreover, H19 silencing protected against OGD/R-triggered cell injury by down-regulating BCL2L13. H19 acted as a sponge of miR-1306-5p and BCL2L13 was a direct target of miR-1306-5p. H19 mediated BCL2L13 expression by sequestering miR-1306-5p. Furthermore, miR-1306-5p was a molecular mediator of H19 function. These results suggested that H19 silencing alleviated OGD/R-triggered I/R injury at least partially depending on the regulation of the miR-1306-5p/BCL2L13 axis.

LncRNA 4344 promotes NLRP3-related neuroinflammation and cognitive impairment by targeting miR-138-5p

OBJECTIVE

Cognitive impairment is a common neurological disease of which NLRP3-related neuroinflammation has been demonstrated to be an essential mediator. Previous studies have indicated that long non-coding RNAs (lncRNAs) are critical for the development of neurological disorders. However, the roles and functions of lncRNA 4344 in neuroinflammation during cognitive impairment are unknown and need to be further elucidated.

METHODS

Lipopolysaccharide (LPS)-induced rat cognitive impairment and rat microglia (RM) cell inflammation models were established in vitro and in vivo. The Morris water maze test was used to evaluate the cognitive behavior of the rats. Gene expression was assessed using real-time quantitative polymerase chain reaction, and protein levels using enzyme-linked immunosorbent assay, or western blot analysis. The targeting relationship between lncRNA 4344, miR-138-5p, and NLRP3 was identified using bioinformatics analysis and a dual-luciferase reporter gene assay. Hematoxylin-Eosin and Nissl stainings, terminal deoxynucleotidyl transferase dUTP nick end labeling, or immunofluorescence staining assays were performed to detect pathological changes, neuronal apoptosis, or positive cells in hippocampal tissues, respectively.

RESULTS

The expression levels of lncRNA 4344 and NLRP3 were upregulated in the hippocampal tissues of LPS-treated rats and RM cells, and showed a strong positive correlation between each other. LncRNA 4344 overexpression further enhanced the expression of NLRP3 and its downstream genes (caspase-1, IL-1β, and IL-18), as well as neuronal apoptosis in LPS-stimulated RM cells, whereas lncRNA 4344 silencing attenuated the inflammatory injuries. Moreover, miR-138-5p was the direct target of lncRNA 4344 and was downregulated in the RM cell inflammation model. We also found that miR-138-5p directly reduced the expression of NLRP3 and its downstream genes. Subsequently, the results of the animal experiments showed that the lncRNA 4344/miR-138-5p/NLRP3 axis plays an essential role in regulating the cognitive behavior, pathological changes and apoptosis of hippocampal neurons, expression of inflammation-related factors (NLRP3, caspase-1, IL-1β, and IL-18), and microglial activation in LPS-induced cognitive impairment rats.

CONCLUSION

Our results demonstrated for the first time that lncRNA 4344 regulates NLRP3-related neuroinflammation and cognitive impairment by targeting miR-138-5p, providing a possible target for the treatment of diseases characterized by a cognitive deficit.

Noncoding RNA crosstalk in brain health and diseases

The mammalian brain expresses several classes of noncoding RNAs (ncRNAs), including long ncRNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs). These ncRNAs play vital roles in regulating cellular processes by RNA/protein scaffolding, sponging and epigenetic modifications during the pathophysiological conditions, thereby controlling transcription and translation. Some of these functions are the result of crosstalk between ncRNAs to form a competitive endogenous RNA network. These intricately organized networks comprise lncRNA/miRNA, circRNA/miRNA, or lncRNA/miRNA/circRNA, leading to crosstalk between coding and ncRNAs through miRNAs. The miRNA response elements predominantly mediate the ncRNA crosstalk to buffer the miRNAs and thereby fine-tune and counterbalance the genomic changes and regulate neuronal plasticity, synaptogenesis and neuronal differentiation. The perturbed levels and interactions of the ncRNAs could lead to pathologic events like apoptosis and inflammation. Although the regulatory landscape of the ncRNA crosstalk is still evolving, some well-known examples such as lncRNA Malat1 sponging miR-145, circRNA CDR1as sponging miR-7, and lncRNA Cyrano and the circRNA CDR1as regulating miR-7, has been shown to affect brain function. The ability to manipulate these networks is crucial in determining the functional outcome of central nervous system (CNS) pathologies. The focus of this review is to highlights the interactions and crosstalk of these networks in regulating pathophysiologic CNS function.

Emerging Role of LncRNAs in Ischemic Stroke-Novel Insights into the Regulation of Inflammation

As a crucial kind of pervasive gene, long noncoding RNAs (lncRNAs) are abundant and key players in brain function as well as numerous neurological disorders, especially ischemic stroke. The mechanisms underlying ischemic stroke include angiogenesis, autophagy, apoptosis, cell death, and neuroinflammation. Inflammation plays a vital role in the pathological process of ischemic stroke, and systemic inflammation affects the patient’s prognosis. Although a great deal of research has illustrated that various lncRNAs are closely relevant to regulate neuroinflammation and microglial activation in ischemic stroke, the specific interactional relationships and mechanisms between lncRNAs and neuroinflammation have not been described clearly. This review aimed to summarize the therapeutic effects and action mechanisms of lncRNAs on ischemia by regulating inflammation and microglial activation. In addition, we emphasize that lncRNAs have the potential to modulate inflammation by inhibiting and activating various signaling pathways, such as microRNAs, NF‐κB and ERK.

Long non-coding RNA H19: Physiological functions and involvements in central nervous system disorders

Central nervous system (CNS) disorders are some of the most complex and challenging diseases because of the intricate structure and functions of the CNS. Long non-coding RNA (LncRNA) H19, which had been mistaken for "transcription noise" previously, has now been found to be closely related to the development and homeostasis of the CNS. Several recent studies indicate that it plays an important role in the pathogenesis, treatment, and even prognosis of CNS disorders. LncRNA H19 is correlated with susceptibility to various CNS disorders such as intracranial aneurysms, ischemic stroke, glioma, and neuroblastoma. Moreover, it participates in the pathogenesis of CNS disorders by regulating transcription, translation, and signaling pathways, suggesting that it is a promising biomarker and therapeutic target for these disorders. This article reviews the functions and mechanisms of lncRNA H19 in various CNS disorders, including cerebral ischemia, cerebral hemorrhage, glioma, pituitary adenoma, neuroblastoma, Parkinson's disease, Alzheimer's disease, traumatic spinal cord injury, neuropathic pain, and temporal lobe epilepsy, to provide a theoretical basis for further research on the role of lncRNA H19 in CNS disorders.

Long noncoding RNA SOX2OT silencing alleviates cerebral ischemia-reperfusion injury via miR-135a-5p-mediated NR3C2 inhibition

OBJECTIVE

This study is aimed to investigate the role of the long noncoding RNA SOX2 overlapping transcript (SOX2OT) in cerebral ischemia-reperfusion injury (CIRI) and the underlying regulatory mechanisms.

METHODS

The oxygen-glucose deprivation/reoxygenation (OGD/R)-treated PC12 cells and middle cerebral artery occlusion/reperfusion (MCAO/R)-treated rats were established to simulate CIRI condition in vitro and in vivo. Quantitative real-time polymerase chain reaction was performed to detect the expression of SOX2OT, microRNA-135a-5p (miR-135a-5p), and nuclear receptor subfamily 3 group C member 2 (NR3C2). The cell viability and apoptosis were analyzed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assays. The levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD), and reactive oxygen species (ROS) or interleukin (IL)-1β and IL-6 were used to evaluate the oxidative stress or inflammation. Dual-luciferase reporter assay was conducted to validate the interactions among SOX2OT, miR-135a-5p, and NR3C2. Additionally, neurological deficit scores (NDS), infarct volume, and brain edema were used to assess brain impairments in vivo.

RESULTS

The expression of SOX2OT and NR3C2 was increased, while miR-135a-5p was decreased in OGD/R-treated PC12 cells. SOX2OT silencing repressed the levels of LDH, MDA, ROS, IL-1β, IL-6, reduced the numbers of TUNEL positive cells, and elevated viability and SOD level in OGD/R-treated PC12 cells. Besides, SOX2OT targeted miR-135a-5p, and miR-135a-5p targeted NR3C2. Both miR-135a-5p downregulation and NR3C2 upregulation reversed the suppressive effects of SOX2OT knockdown on oxidative stress, apoptosis, and inflammation of OGD/R-treated PC12 cells. Furthermore, injection of sh-SOX2OT reduced the NDS, cerebral infarct, and cerebral edema in MCAO/R-treated rats.

CONCLUSIONS

Silencing of SOX2OT attenuated CIRI via regulation of the miR-135a-5p/NR3C2 axis, which may provide a novel therapeutic target for CIRI.

Role of lncRNAs in the Development of Ischemic Stroke and Their Therapeutic Potential

Stroke is a major cause of premature mortality and disability around the world. Therefore, identification of cellular and molecular processes implicated in the pathogenesis and progression of ischemic stroke has become a priority. Long non-coding RNAs (lncRNAs) are emerging as significant players in the pathophysiology of cerebral ischemia. They are involved in different signalling pathways of cellular processes like cell apoptosis, autophagy, angiogenesis, inflammation, and cell death, impacting the progression of cerebral damage. Exploring the functions of these lncRNAs and their mechanism of action may help in the development of promising treatment strategies. In this review, the current knowledge of lncRNAs in ischemic stroke, focusing on the mechanism by which they cause cellular apoptosis, inflammation, and microglial activation, has been summarized. Very few lncRNAs have been functionally annotated. Therefore, the therapies based on lncRNAs still face many hurdles since the potential targets are likely to increase with the identification of new ones. Majority of experiments involving the identification and function of lncRNAs have been carried out in animal models, and the role of lncRNAs in human stroke presents a challenge. However, mitigating these issues through more rational experimental design might lead to the development of lncRNA-based stroke therapies to treat ischemic stroke.

Long Noncoding RNA/Circular RNA-miRNA-mRNA Axes in Ischemia-Reperfusion Injury

Ischemia-reperfusion injury (IRI) elicits tissue injury involved in a wide range of pathologies. Multiple studies have demonstrated that noncoding RNAs (ncRNAs), including long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs), participate in the pathological development of IRI, and they may act as biomarkers, therapeutic targets, or prognostic indicators. Nonetheless, the specific molecular mechanisms of ncRNAs in IRI have not been completely elucidated. Regulatory networks among lncRNAs/circRNAs, miRNAs, and mRNAs have been the focus of attention in recent years. Studies on the underlying molecular mechanisms have contributed to the discovery of therapeutic targets or strategies in IRI. In this review, we comprehensively summarize the current research on the lncRNA/circRNA-miRNA-mRNA axes and highlight the important role of these axes in IRI.