An Antagomir to MicroRNA-106b-5p Ameliorates Cerebral Ischemia and Reperfusion Injury in Rats Via Inhibiting Apoptosis and Oxidative Stress

Plasma miRNAs as potential biomarkers for schizophrenia in a Jordanian cohort

Background

Schizophrenia (SZ), a complex and chronic neuropsychiatric disorder affecting approximately 1 % of the general population, presents diagnostic challenges due to the absence of reliable biomarkers, and relying mainly on clinical observations. MicroRNAs (miRNAs) signatures in a wide range of diseases, including psychiatric disorders, hold immense potential for serving as biomarkers. This study aimed to analyze the expression levels of specific microRNAs (miRNAs) namely miR-29b-3p, miR-106b-5p, and miR-199a-3p and explore their diagnostic potential for SZ in Jordanian patients.

Methods

Small RNAs (miRNAs) were extracted from plasma samples of 30 SZ patients and 35 healthy controls. RNA was reverse transcribed and quantified by real-time polymerase chain reaction (qRT-PCR). The expression levels of three miRNAs (miR-29b-3p, miR-106b-5p and miR-199a-3p) were analyzed. Receiver operating characteristic (ROC) curves analysis was performed to evaluate diagnostic value of these miRNAs. Target genes prediction, functional enrichment and pathway analyses were done using miRWalk and Metascape. STRING database was used to construct protein-protein network and identify hub genes.

Results

Notably, miR-106b-5p and miR-199a-3p were significantly upregulated (p < 0.0001), while miRNA-29b-3p was downregulated (p < 0.0001) in SZ patients compared to controls. The diagnostic potential was assessed through ROC curves, revealing substantial diagnostic value for miR-199a-3p (AUC: 0.979) followed by miR-106b-5p (AUC: 0.774), with limited diagnostic efficacy for miR-29b-3p. Additionally, bioinformatic analyses for the predicted target genes of the diagnostically significant miRNAs uncovered Gene Ontology (GO) terms related to neurological development, including morphogenesis, which is involved in neuron differentiation, brain development, head development, and neuron projection morphogenesis. These findings highlight a potential connection between the identified miRNAs and SZ pathophysiology in the studied Jordanian population. Furthermore, a protein-protein interaction network from the target genes identified in association with neurological development in the Gene Ontology (GO) terms deepens our comprehension of the molecular landscape of the regulated target genes.

Conclusions

This comprehensive exploration highlights the promising role of miRNAs in unraveling intricate molecular pathways associated with SZ in the Jordanian cohort and suggests that plasma miRNAs could serve as reliable biomarkers for SZ diagnosis and disease progression. Remarkably, this study represents the first investigation into the role of circulating miRNA expression among Jordanian patients with SZ, providing valuable insights into the diagnostic landscape of this disorder.

CircRNA-associated ceRNA regulatory networks as emerging mechanisms governing the development and biophysiopathology of epilepsy

The etiology of epilepsy is ascribed to the synchronized aberrant neuronal activity within the brain. Circular RNAs (circRNAs), a class of non-coding RNAs characterized by their circular structures and covalent linkage, exert a substantial influence on this phenomenon. CircRNAs possess stereotyped replication, transience, repetitiveness, and paroxysm. Additionally, MicroRNA (miRNA) plays a crucial role in the regulation of diverse pathological processes, including epilepsy. CircRNA is of particular significance due to its ability to function as a competing endogenous RNA, thereby sequestering or inhibiting miRNA activity through binding to target mRNA. Our review primarily concentrates on elucidating the pathological and functional roles, as well as the underlying mechanisms, of circRNA-miRNA-mRNA networks in epilepsy. Additionally, it explores the potential utility of these networks for early detection and therapeutic intervention.

MiRNAs as potential therapeutic targets and biomarkers for non-traumatic intracerebral hemorrhage

Non-traumatic intracerebral hemorrhage (ICH) is the most common type of hemorrhagic stroke, most often occurring between the ages of 45 and 60. Hypertension is most often the cause of ICH. Less often, atherosclerosis, blood diseases, inflammatory changes in cerebral vessels, intoxication, vitamin deficiencies, and other reasons cause hemorrhages. Cerebral hemorrhage can occur by diapedesis or as a result of a ruptured vessel. This very dangerous disease is difficult to treat, requires surgery and can lead to disability or death. MicroRNAs (miRNAs) are a class of non-coding RNAs (about 18-22 nucleotides) that are involved in a variety of biological processes including cell differentiation, proliferation, apoptosis, etc., through gene repression. A growing number of studies have demonstrated miRNAs deregulation in various cardiovascular diseases, including ICH. In addition, given that computed tomography (CT) and/or magnetic resonance imaging (MRI) are either not available or do not show clear signs of possible vessel rupture, accurate and reliable analysis of circulating miRNAs in biological fluids can help in early diagnosis for prevention of ICH and prognosis patient outcome after hemorrhage. In this review, we highlight the up-to-date findings on the deregulated miRNAs in ICH, and the potential use of miRNAs in clinical settings, such as therapeutic targets and non-invasive diagnostic/prognostic biomarker tools.

Unveiling the regulatory role of miRNAs in stroke pathophysiology and diagnosis

Stroke, a major global cause of mortality, leads to a range of problems for those who survive. Besides its brutal events, stroke also tends to have a characteristic of recurrence, making it a complex disease involving intricate regulatory networks. One of the major cellular regulators is the non-coding RNAs (ncRNA), specifically microRNAs (miRNAs), thus the possible functions of miRNAs in the pathogenesis of stroke are discussed as well as the possibility of using miRNA-based therapeutic approaches. Firstly, the molecular mechanisms by which miRNAs regulate vital physiological processes, including synaptic plasticity, oxidative stress, apoptosis, and the integrity of the blood-brain barrier (BBB) are reviewed. The miRNA indirectly impacts stroke outcomes by regulating BBB function and angiogenesis through the targeting of transcription factors and angiogenic factors. In addition, the tendency for some miRNAs to be upregulated in response to hypoxia, which is a prevalent phenomenon in stroke and various neurological disorders, highlights the possibility that it controls hypoxia-inducible factor (HIF) signaling and angiogenesis, thereby influencing the integrity of the BBB as examples of the discussed mechanisms. Furthermore, this review explores the potential therapeutic targets that miRNAs may offer for stroke recovery and highlights their promising capacity to alleviate post-stroke complications. This review provides researchers and clinicians with valuable resources since it attempts to decipher the complex network of miRNA-mediated mechanisms in stroke. Additionally, the review addresses the interplay between miRNAs and stroke risk factors as well as clinical applications of miRNAs as diagnostic and prognostic markers.

The microRNAs (miRs) overexpressing mesenchymal stem cells (MSCs) therapy in neurological disorders; hope or hype

Altered expression of multiple miRNAs was found to be extensively involved in the pathogenesis of different neurological disorders including Alzheimer's disease, Parkinson's disease, stroke, epilepsy, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington's disease. One of the biggest concerns within gene-based therapy is the delivery of the therapeutic microRNAs to the intended place, which is obligated to surpass the biological barriers without undergoing degradation in the bloodstream or renal excretion. Hence, the delivery of modified and unmodified miRNA molecules using excellent vehicles is required. In this light, mesenchymal stem cells (MSCs) have attracted increasing attention. The MSCs can be genetically modified to express or overexpress a particular microRNA aimed with promote neurogenesis and neuroprotection. The current review has focused on the therapeutic capabilities of microRNAs-overexpressing MSCs to ameliorate functional deficits in neurological conditions.

Extracellular vesicle-encapsulated miR-10a-5p derived from MDSCs restrains germinal center B cells in experimental Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is a progressive systemic autoimmune disease characterized by chronic inflammation of the exocrine glands, resulting in damage to the salivary and lacrimal glands. Our group and other researchers have reported that myeloid-derived suppressor cell-derived extracellular vesicles (MDSC-EVs) could attenuate the progression of autoimmune disease by impairing T-cell function. However, the effect of MDSC-EVs on B-cell function and the underlying mechanism remains largely unknown. In this study, we found that MDSC-EVs significantly attenuated the progression of experimental Sjögren's syndrome (ESS). Moreover, treatment with MDSC-EVs via intravenous injection markedly reduced the percentage of germinal center (GC) B cells in ESS mice. In vitro, MDSC-EVs could directly suppress the generation of GC B cells and the expression of B cell lymphoma 6 (Bcl-6) in B cells under GC B-cell-polarizing conditions. Mechanistically, miR-10a-5p carried by MDSC-EVs regulated the differentiation of GC B cells by targeting Bcl-6, and inhibition of miR-10a-5p in MDSC-EVs significantly reversed the effect of MDSC-EVs involved in alleviating the development of ESS. Taken together, our findings demonstrated that miR-10a-5p carried by MDSC-EVs inhibited the generation of B cells by targeting Bcl-6 and eventually alleviated the progression of ESS, which may provide novel therapeutic targets for the treatment of pSS.

Silencing of microRNA-106b-5p prevents doxorubicin-mediated cardiotoxicity through modulation of the PR55α/YY1/sST2 signaling axis

Clinical use of doxorubicin (Dox), an anthracycline with potent anti-tumor effects, is limited because of its highly chemotherapy-induced cardiotoxicity (CIC). After myocardial infarction (MI), we have recently identified Yin Yang-1 (YY1) and histone deacetylase 4 (HDAC4) as two factors involved in the overexpression of the isoform soluble suppression of tumorigenicity 2 (sST2) protein, which acts as a decoy receptor blocking the favorable effects of IL-33. Therefore, high levels of sST2 are associated with increased fibrosis, remodeling, and worse cardiovascular outcomes. No data exist on the role of the YY1/HDAC4/sST2 axis in CIC. This study aimed to evaluate the pathophysiological implication of the molecular YY1/HDAC4/sST2 axis in remodeling that is developed in patients treated with Dox as well as to suggest a novel molecular therapy to prevent anthracycline-induced cardiotoxicity. Here, we have characterized a novel nexus between miR106b-5p (miR-106b) levels and the YY1/HDAC4 axis in relation to the cardiac expression of sST2 using two experimental models with Dox-induced cardiotoxicity. The addition of Dox (5 μM) to human induced pluripotent stem cell-derived cardiomyocytes induced cellular apoptotic death via upregulation of miR-106b-5p (miR-106b), which was confirmed by specific mimic sequences. A functional blockage of miR-106b using the locked nucleic acid antagomir inhibited Dox-induced cardiotoxicity.

Anti-microRNA-1976 as a Novel Approach to Enhance Chemosensitivity in XAF1+ Pancreatic and Liver Cancer

The current cancer treatments using chemoagents are not satisfactory in terms of outcomes and prognosis. Chemoagent treatments result in cell death or arrest, but the accompanying cellular responses are not well-studied. Exosomes, which are extracellular vesicles secreted by living cells, might mediate cellular responses through microRNAs. We found that miR-1976 was highly enriched in exosomes secreted after chemoagent treatment. We developed a novel approach for in situ mRNA target screening and discovered several miR-1976-specific mRNA targets, including the proapoptotic gene XAF1, which was targeted by miR-1976 and which suppressed chemoagent-induced cell apoptosis. Increased RPS6KA1 gene transcription was associated with the increase in its intronic pre-miR-1976 expression. Blockade of miR-1976 could enhance chemosensitivities of hepatoma and pancreatic cancer cells in an XAF1-dependent manner, as evidenced by increased levels of cell apoptosis, reduced IC50 in cell toxicity assays, and suppressed tumor growth in animal xenograft experiments in vivo. We propose that intracellular levels of miR-1976 determine chemosensitivity, and its blockade could be a novel strategy and potential therapeutic application in cancer treatment.

Amorfrutin B Protects Mouse Brain Neurons from Hypoxia/Ischemia by Inhibiting Apoptosis and Autophagy Processes Through Gene Methylation- and miRNA-Dependent Regulation

Amorfrutin B is a selective modulator of the PPARγ receptor, which has recently been identified as an effective neuroprotective compound that protects brain neurons from hypoxic and ischemic damage. Our study demonstrated for the first time that a 6-h delayed post-treatment with amorfrutin B prevented hypoxia/ischemia-induced neuronal apoptosis in terms of the loss of mitochondrial membrane potential, heterochromatin foci formation, and expression of specific genes and proteins. The expression of all studied apoptosis-related factors was decreased in response to amorfrutin B, both during hypoxia and ischemia, except for the expression of anti-apoptotic BCL2, which was increased. After post-treatment with amorfrutin B, the methylation rate of the pro-apoptotic Bax gene was inversely correlated with the protein level, which explained the decrease in the BAX/BCL2 ratio as a result of Bax hypermethylation. The mechanisms of the protective action of amorfrutin B also involved the inhibition of autophagy, as evidenced by diminished autophagolysosome formation and the loss of neuroprotective properties of amorfrutin B after the silencing of Becn1 and/or Atg7. Although post-treatment with amorfrutin B reduced the expression levels of Becn1, Nup62, and Ambra1 during hypoxia, it stimulated Atg5 and the protein levels of MAP1LC3B and AMBRA1 during ischemia, supporting the ambiguous role of autophagy in the development of brain pathologies. Furthermore, amorfrutin B affected the expression levels of apoptosis-focused and autophagy-related miRNAs, and many of these miRNAs were oppositely regulated by amorfrutin B and hypoxia/ischemia. The results strongly support the position of amorfrutin B among the most promising anti-stroke and wide-window therapeutics.

Emerging Treatment Strategies for Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia-reperfusion injury (CI/RI) injury is a common feature of ischemic stroke which occurs when the blood supply is restored after a period of ischemia in the brain. Reduced blood-flow to the brain during CI/RI compromises neuronal cell health as a result of mitochondrial dysfunction, oxidative stress, cytokine production, inflammation and tissue damage. Reperfusion therapy during CI/RI can restore the blood flow to ischemic regions of brain which are not yet infarcted. The long-term goal of CI/RI therapy is to reduce stroke-related neuronal cell death, disability and mortality. A range of drug and interventional therapies have emerged that can alleviate CI/RI mediated oxidative stress, inflammation and apoptosis in the brain. Herein, we review recent studies on CI/RI interventions for which a mechanism of action has been described and the potential of these therapeutic modalities for future use in the clinic.

Multi-omics research strategies in ischemic stroke: A multidimensional perspective

Ischemic stroke (IS) is a multifactorial and heterogeneous neurological disorder with high rate of death and long-term impairment. Despite years of studies, there are still no stroke biomarkers for clinical practice, and the molecular mechanisms of stroke remain largely unclear. The high-throughput omics approach provides new avenues for discovering biomarkers of IS and explaining its pathological mechanisms. However, single-omics approaches only provide a limited understanding of the biological pathways of diseases. The integration of multiple omics data means the simultaneous analysis of thousands of genes, RNAs, proteins and metabolites, revealing networks of interactions between multiple molecular levels. Integrated analysis of multi-omics approaches will provide helpful insights into stroke pathogenesis, therapeutic target identification and biomarker discovery. Here, we consider advances in genomics, transcriptomics, proteomics and metabolomics and outline their use in discovering the biomarkers and pathological mechanisms of IS. We then delineate strategies for achieving integration at the multi-omics level and discuss how integrative omics and systems biology can contribute to our understanding and management of IS.

Some miRNA expressions and their targets in ischemic stroke

Ischemic stroke (IS) is a global health challenge leading to life-long disabilities or the deaths of patients. IS is a complex disease where genetic and environmental factors are both concerned with the pathophysiology of the condition. Here, we aimed to investigate various microRNA (miRNA) expressions and their targets in IS. A rapid and accurate diagnosis of acute IS is important to perform appropriate treatment. Therefore, there is a need for a more rapid and simple tool to carry out an acute diagnosis of IS. miRNAs are small RNA molecules serving as precious biomarkers due to their easy detection and stability in blood samples. The present systematic review aimed to summarize previous studies investigating several miRNA expressions and their targets in IS.

Modulation of Microglia M2 Polarization and Alleviation of Hippocampal Neuron Injury By MiR-106b-5p/RGMa in a Mouse Model of Status Epilepticus

MicroRNAs (miRNAs) regulate gene expression at the post-transcriptional level. The miRNA miR-106b-5p has been linked to epilepsy, but its specific role and mechanism of action remain unclear. This was investigated in the present study using a mouse model of pilocarpine-induced status epilepticus and an in vitro system of HT22 hippocampal cells treated with Mg²⁺-free solution and cocultured with BV2 microglia cells. We found that inhibiting miR-106b-5p expression promoted microglia M2 polarization, reduced the inflammatory response, and alleviated neuronal injury. These effects involved modulation of the repulsive guidance molecule A (RGMa)-Rac1-c-Jun N-terminal kinase (JNK)/p38-mitogen-activated protein kinase (MAPK) signaling axis. Our results suggest that therapeutic strategies targeting miR-106b-5p or downstream factors can be effective in preventing epileptogenesis or treating epilepsy.

miRNA Involvement in Cerebral Ischemia-Reperfusion Injury

Cerebral ischemia reperfusion injury is a debilitating medical condition, currently with only a limited amount of therapies aimed at protecting the cerebral parenchyma. Micro RNAs (miRNAs) are small, non-coding RNA molecules that via the RNA-induced silencing complex either degrade or prevent target messenger RNAs from being translated and thus, can modulate the synthesis of target proteins. In the neurological field, miRNAs have been evaluated as potential regulators in brain development processes and pathological events. Following ischemic hypoxic stress, the cellular and molecular events initiated dysregulate different miRNAs, responsible for long-terming progression and extension of neuronal damage. Because of their ability to regulate the synthesis of target proteins, miRNAs emerge as a possible therapeutic strategy in limiting the neuronal damage following a cerebral ischemic event. This review aims to summarize the recent literature evidence of the miRNAs involved in signaling and modulating cerebral ischemia-reperfusion injuries, thus pointing their potential in limiting neuronal damage and repair mechanisms. An in-depth overview of the molecular pathways involved in ischemia reperfusion injury and the involvement of specific miRNAs, could provide future perspectives in the development of neuroprotective agents targeting these specific miRNAs.

MiR-106b-5p Attenuates Neuropathic Pain by Regulating the P2X4 Receptor in the Spinal Cord in Mice

The P2X4 receptor (P2X4R) can be upregulated after nerve injury, and its mediated spinal microglial activation makes a critical contribution to pathologically enhanced pain processing in the dorsal horn. Although some studies have partly clarified the mechanism underlying altered P2X4R expression, the specific mechanism is not well understood. MicroRNAs (miRNAs) are small noncoding RNAs which control gene expression by binding with their target mRNAs. Thus, in the present study, we investigated whether miRNA is involved in the pathogenesis of neuropathic pain by regulating P2X4R. Our results showed that P2X4R was upregulated in the spinal dorsal horn of mice following spared nerve injury (SNI), and 69 miRNAs (46 upregulated and 23 downregulated miRNAs) were differentially expressed (fold change > 2.0, P < 0.05). P2X4R was found to be a major target of miR-106b-5p (one of the downregulated miRNAs) using bioinformatics technology; quantitative real-time PCR analysis confirmed the change in expression of miR-106b-5p, and dual-luciferase reporter assays confirmed the correlation between them. Fluorescence in situ hybridization was used to show cell co-localization of P2X4R and miR-106b-5p in the spinal dorsal horn. Transfection with miR-106b-5p mimic into BV2 cells reversed the upregulation of P2X4R induced by lipopolysaccharide (LPS). Moreover, miR-106b-5p overexpression significantly attenuated neuropathic pain induced by SNI, with decreased expression of P2X4R mRNA and protein in the spinal dorsal horn; intrathecal miR-106b-5p antagomir induced pain behaviors, and increased expression of P2X4R in the spinal dorsal horn of naïve mice. These data suggest that miR-106b-5p can serve as an important regulator of neuropathic pain development by targeting P2X4R.

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.

Gomisin J attenuates cerebral ischemia/reperfusion injury by inducing anti-apoptotic, anti-inflammatory, and antioxidant effects in rats

Ischemic stroke is one of the leading causes of morbidity and mortality in humans. Cerebral ischemia-reperfusion (CIR) injury serves as a leading cause of stroke. Schisandra chinensis is a well-known Chinese traditional medicine. In this study, we explored the role of Gomisin J (GJ), a compound of S. chinensis, in CIR using a middle cerebral artery occlusion/reperfusion rat model and the possible mechanisms. We identified that GJ reduced neurological scores, cerebral infarction, and water content in the I/R rat brain. Importantly, GJ rescued I/R treatment-reduced neuron survival in the hippocampus, inhibited apoptosis of ischemic tissues in I/R rats, increased B-cell lymphoma-extra-large (Bcl-XL) expression, and reduced the levels of cleaved caspase-3, Bax, cyclooxygenase-2, nuclear factor kappa-B, and nitric oxide in I/R rat brain tissues. Furthermore, GJ treatment enhanced nuclear factor E2 related factor 2 (Nrf2) translocation, heme oxygenase-1 (HO-1) expression, superoxide dismutase and glutathione peroxidase activities, and glutathione level. Overall, GJ treatment GJ attenuates CIR injury by inducing anti-apoptotic, antioxidant, and anti-inflammatory effects in vivo.

Influence of age and sex on microRNA response and recovery in the hippocampus following sepsis

Sepsis, defined as a dysregulated host immune response to infection, is a common and dangerous clinical syndrome. The excessive host inflammatory response can induce immediate and persistent cognitive decline, which can be worse in older individuals. Sex-specific differences in the outcome of infectious diseases and sepsis appear to favor females. We employed a murine model to examine the influence of age and sex on the brain's microRNA (miR) response following sepsis. Young and old mice of both sexes underwent cecal ligation and puncture (CLP) with daily restraint stress. Expression of hippocampal miR was examined in age- and sex-matched controls at 1 and 4 days post-CLP. Few miR were modified in a similar manner across age or sex and these few miR were generally associated with neuroprotection against inflammation. Similar to previous work examining transcription, young females exhibited a better recovery of the miR profile from day 1 to day 4, relative to young males and old females. For young males and all female groups, the initial response mainly involved a decrease in miR expression. In contrast, old males exhibited only upregulated miR on day 1 and day 4 and many of the miR upregulated on day 1 and day 4 were linked to neurodegeneration, increased neuroinflammation, and cognitive impairment. The results emphasize age and sex differences in epigenetic mechanisms that likely contribute to susceptibility or resilience to cognitive impairment due to sepsis.

MiRNA-122 Promotes Ischemia-Reperfusion Injury after Lung Transplantation via the Toll-like Receptor Signaling Pathway

OBJECTIVE

MiRNAs have been recently implicated in the pathogenesis of ischemia-reperfusion (IR) injury. This study aimed to investigate the miRNA expression profiles in the early stages after lung transplantation (LT) and to study the involvement of the Toll-like receptor (TLR) signaling pathway in lung IR injury following LT.

METHODS

We established the left LT model in mice and selected the miRNA-122 as a research target. The mice were injected with a miRNA-122-specific inhibitor, following which pathological changes in the lung tissue were studied using different lung injury indicators. In addition, we performed deep sequencing of transplanted lung tissues to identify differentially expressed (DE) miRNAs and their target genes. These target genes were used to further perform gene ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis.

RESULTS

A total of 12 DE miRNAs were selected, and 2476 target genes were identified. The GO enrichment analysis predicted 6063 terms, and the KEGG analysis predicted 1554 biological pathways. Compared with the control group, inhibiting the expression of miRNA-122 significantly reduced the lung injury and lung wet/dry ratio (P<0.05). In addition, the activity of myeloperoxidase and the expression levels of tumor necrosis factor-alpha and TLR2/4 were decreased (P<0.05); whereas the expression of interleukin-10 was increased (P<0.05). Furthermore, the inhibition of miRNA-122 suppressed the IR injury-induced activation of the TLR signaling pathway.

CONCLUSION

Our findings showed the differential expression of several miRNAs in the early inflammatory response following LT. Of these, miRNA-122 promoted IR injury following LT, whereas its inhibition prevented IR injury in a TLR-dependent manner.

MicroRNA-32-5p attenuates cerebral ischemia/reperfusion injuries by modulating the phosphatase and tensin homologous protein

Non-coding RNAs have recently attracted much attention with the potential in the treatment of cerebral ischemia/reperfusion (I/R) injuries. In this study, we investigated the role of miR-32-5p in cerebral I/R injuries by using oxygen-glucose deprivation/reperfusion (OGD/R) PC12 cells and middle cerebral artery occlusion/reperfusion (MCAO/R) rats. The expression of genes and proteins were detected by RT-qPCR and Western blot, respectively. The function of OGD/R PC12 cells was detected using MTT assay and flow cytometry analysis. The influences of MCAO/R on rats was evaluated by measuring the infarct volume and brain water content. Bioinformatics analysis and luciferase gene reporter assay were used to identify the relationship between miR-32-5p and PTEN. The results showed that miR-32-5p had neuroprotective effects on OGD/R induced PC12 cells and MCAO/R injured rats' brain. The level of miR-32-5p was significantly reduced after OGD/R. Overexpression of miR-32-5p significantly reduced MCAO/R-induced brain damages in rats. Moreover, PTEN was found to be a target of miR-32-5p, and overexpression of PTEN attenuated the effects of miR-32-5p overexpression on cerebral I/R injuries. In addition, miR-32-5p was able to activate PI3K/AKT signaling by inhibiting PTEN. In conclusion, miR-32-5p prevents brain I/R injuries through modulating PTEN/PI3K/AKT signaling pathway.

MicroRNA-424 alleviates neurocyte injury by targeting PDCD4 in a cellular model of cerebral ischemic stroke

Cerebral ischemic stroke is the primary cause of stroke-associated mortality and disability, and current therapeutic options are limited and ineffective. The present study aimed to investigate the potential of apoptotic therapy and the role of microRNA (miR)-424 in cerebral ischemic stroke. PC12 cells, a cloned cell line from rat adrenal pheochromocytoma, were treated with CoCl₂ to construct a cellular ischemia model. mRNA and protein levels of programmed cell death protein 4 (PDCD4), Bcl-2, Bax, caspase-3, PI3K and AKT were evaluated using reverse transcription-quantitative PCR and western blot analyses, respectively. Cell Counting Kit-8 assays were performed to examine cell viability in the ischemia model. Flow cytometry was conducted to evaluate the apoptosis of ischemic cells. Furthermore, a luciferase assay was performed to verify the target gene of miR-424. It was revealed that the expression level of miR-424 was downregulated in the ischemia model, while the expression of PDCD4 was upregulated. Moreover, the expression of miR-424 was increased after treatment with miR-424 mimics. The mRNA and protein expression of PDCD4 was upregulated after transfection with pcDNA3.1-PDCD4. PDCD4 was predicted and demonstrated to be a target of miR-424. Notably, overexpression of miR-424 increased cell viability and inhibited apoptosis in the ischemia model, which was reversed by co-treatment with pcDNA3.1-PDCD4. Furthermore, overexpression of miR-424 regulated the expression of PDCD4, Bax, Bcl-2, phosphorylated-PI3K/AKT and caspase-3, which was restored after co-transfection with pcDNA3.1-PDCD4. Collectively, the results indicated that miR-424 regulated the progression of cerebral ischemic stroke in a cellular model by targeting PDCD4.

miR-106b-5p upregulation is associated with microglial activation and inflammation in the mouse hippocampus following status epilepticus

To investigate the association of miR-106b-5p with neuroinflammation and microglial activation in a status epilepticus (SE) mouse model. We examined changes in the expression of microRNA-106b-5p (miRNA-106b-5p), repulsive guidance molecule A (RGMa), triggering receptor expressed on myeloid cells 2 (TREM2), and the microglia-related markers interleukin (IL)-1β, IL-4, IL-6, IL-10, inducible nitric oxide synthase (iNOS), and arginase-1 (Arg-1) in the mouse hippocampus of the lithium-pilocarpine-induced SE mouse model. Eighty-four female C57BL/6 mice were randomly divided into a normal control group (n = 12), and six SE groups (n = 12/group), which were monitored at 6 h and at 1, 3, 7, 14, and 21 days (d) post-SE induction. Unlike in the dentate gyrus, immunohistochemical staining revealed prominent neuronal swelling at 6 h, significant neuronal loss and apoptosis on day 3, and recovery by day 14 in the hippocampal cornu ammonis (CA)1 and CA3 pyramidal cells in SE mice. We noted elevated levels of miRNA-106b-5p and all microglia-related markers, which peaked at 3 days post-SE, except IL-4, which peaked at 7 days post-SE, indicating inflammation and microglial activation. RGMa and TREM2 levels decreased at 6 h post-SE. All markers but miRNA-106b-5p, RGMa, and TREM2 returned to baseline levels at 21 days post-SE. Dual luciferase reporter gene assay showed that microRNA-106b-5p can interact with RGMa. We observed that miR-106b-5p level increased while both RGMa and TREM2 levels decreased post-SE and showed associations with microglial activation and inflammation in the mouse hippocampus, suggesting their potential as SE therapeutic targets.

TIMP3 attenuates cerebral ischemia/reperfusion-induced apoptosis and oxidative stress in neurocytes by regulating the AKT pathway

Ischemic stroke seriously threatens human health and creates a large social burden. The present study investigated whether tissue inhibitor of metalloproteinases-3 (TIMP3) prevented cerebral ischemia/reperfusion (I/R), with the aim to explore the underlying mechanism. A transient middle cerebral artery occlusion model was conducted in mice, and oxygen glucose deprivation and reoxygenation (OGD/R) was investigated in PC12 cells to mimic cerebral ischemia-reperfusion injury (CIRI). Western blotting was used to determine the expression of TIMP3, Bax, Bcl-2 and AKT. TUNEL was used to detect apoptosis in cerebral tissues or cultured PC12 cells. Expression levels of reactive oxygen species (ROS), superoxide dismutase (SOD) and malondialdehyde (MDA) were detected to reveal oxidative stress. The results demonstrated that TIMP3 expression was significantly decreased after I/R in vivo or OGD/R in vitro, and the number of TUNEL-positive cells was reduced by the overexpression of TIMP3. The attenuation of Bax/Bcl-2 ratio in OGD/R-induced PC12 cells suppressed the expression levels of ROS and MDA; while also elevating SOD activity in the OGD/R-induced neurocytes in vitro. In addition, TIMP3-overexpression reversed the downregulation of phosphorylated-AKT (Thr308 and Ser473) in OGD/R-treated PC12 cells. However, the anti-apoptotic and anti-oxidative stress roles of TIMP3 in OGD/R-induced PC12 cells were partially abolished after treatment with the AKT inhibitor, AZD5363. Overall, TIMP3 exerted an anti-apoptotic and anti-oxidative stress role in CIRI through the AKT pathway, which may be a potential therapeutic target for the treatment of CIRI.

The Role of MicroRNAs in Mitochondria-Mediated Eye Diseases

The retina is among the most metabolically active tissues with high-energy demands. The peculiar distribution of mitochondria in cells of retinal layers is necessary to assure the appropriate energy supply for the transmission of the light signal. Photoreceptor cells (PRs), retinal pigment epithelium (RPE), and retinal ganglion cells (RGCs) present a great concentration of mitochondria, which makes them particularly sensitive to mitochondrial dysfunction. To date, visual loss has been extensively correlated to defective mitochondrial functions. Many mitochondrial diseases (MDs) show indeed neuro-ophthalmic manifestations, including retinal and optic nerve phenotypes. Moreover, abnormal mitochondrial functions are frequently found in the most common retinal pathologies, i.e., glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy (DR), that share clinical similarities with the hereditary primary MDs. MicroRNAs (miRNAs) are established as key regulators of several developmental, physiological, and pathological processes. Dysregulated miRNA expression profiles in retinal degeneration models and in patients underline the potentiality of miRNA modulation as a possible gene/mutation-independent strategy in retinal diseases and highlight their promising role as disease predictive or prognostic biomarkers. In this review, we will summarize the current knowledge about the participation of miRNAs in both rare and common mitochondria-mediated eye diseases. Definitely, given the involvement of miRNAs in retina pathologies and therapy as well as their use as molecular biomarkers, they represent a determining target for clinical applications.

The Fibroblast-Like Synoviocyte Derived Exosomal Long Non-coding RNA H19 Alleviates Osteoarthritis Progression Through the miR-106b-5p/TIMP2 Axis

Osteoarthritis (OA) is a common degenerative joint disease that affects people worldwide. The interaction between fibroblast-like synoviocytes (FLSs) and chondrocytes may play a vital role in OA disease pathology. However, the underlying mechanisms by which FLSs exert regulatory effects on chondrocytes still need to be elucidated. Exosomes, small membrane vesicles secreted from living cells, are known to play a variety of roles in mediating cell-to-cell communication through the transferring of biological components such as non-coding RNAs and proteins. Here, we investigate the cellular processes of chondrocytes regulated by FLS-derived exosomes and the mechanisms of action underlying the functions of exosomes in OA pathogenesis. We observed that exosome-mediated cartilage repair was characterized by increased cell viability and migration as well as alleviated matrix degradation. Using chondrocyte cultures, the enhanced cellular proliferation and migration during exosome-mediated cartilage repair was linked to the exosomal lncRNA H19-mediated regulation of the miR-106b-5p/TIMP2 axis. Transfection of miR-106-5p mimics in chondrocytes significantly decreased cell proliferation and migration, promoted matrix degradation characterized by elevated MMP13 and ADAMTS5 expression, and reduced the expression of COL2A1 and ACAN in chondrocytes. Furthermore, we found that TIMP2 was directly regulated by miR-106-5p. Co-transfections of miR-106-5p mimics and TIMP2 resulted in higher levels of COL2A1 and ACAN, but lower levels of MMP13 and ADAMTS5. Together, these observations demonstrated that the lncRNA H19 may promote chondrocyte proliferation and migration and inhibit matrix degradation in OA possibly by targeting the miR-106b-5p/TIMP2 axis. In the future, H19 may serve as a potential therapeutic target for the treatment of OA.

Platelets as drivers of ischemia/reperfusion injury after stroke

Ischemic stroke is a leading cause of morbidity and mortality worldwide and, despite reperfusion either via thrombolysis or thrombectomy, stroke patients often suffer from lifelong disabilities. These persistent neurological deficits may be improved by treating the ischemia/reperfusion (I/R) injury that occurs following ischemic stroke. There are currently no approved therapies to treat I/R injury, and thus it is imperative to find new targets to decrease the burden of ischemic stroke and related diseases. Platelets, cell fragments from megakaryocytes, are primarily known for their role in hemostasis. More recently, investigators have studied the nonhemostatic role of platelets in inflammatory pathologies, such as I/R injury after ischemic stroke. In this review, we seek to provide an overview of how I/R can lead to platelet activation and how activated platelets, in turn, can exacerbate I/R injury after stroke. We will also discuss potential mechanisms by which platelets may ameliorate I/R injury.

Exosomes derived from hypoxic bone marrow mesenchymal stem cells rescue OGD-induced injury in neural cells by suppressing NLRP3 inflammasome-mediated pyroptosis

Exosomes have been shown to have therapeutic potential for cerebral ischemic diseases. In this study, we investigated the neuroprotective effects of normoxic and hypoxic bone marrow mesenchymal stromal cells-derived exosomes (N-BM-MSCs-Exo and H-BM-MSCs-Exo, respectively) on oxygen-glucose deprivation (OGD) injury in mouse neuroblastoma N2a cells and rat primary cortical neurons. The proportions of dead cells in N2a and primary cortical neurons after OGD injury were significantly increased, and N-BM-MSCs-Exo (40 μg/ml) could reduce the ratios, noteworthily, the protective effects of H-BM-MSCs-Exo (40 μg/ml) were more potent. Western blotting analysis indicated that N-BM-MSCs-Exo decreased the expression of NLRP3, ASC, Caspase-1, GSDMD-N, cleaved IL-1β and IL-18 in N2a cells. However, H-BM-MSCs-Exo (40 μg/ml) was more powerful in inhibiting the expression of these proteins in comparison with N-BM-MSCs-Exo. Similar results were obtained in primary cortical neurons. Immunofluorescence assays showed that after N-BM-MSCs-Exo and H-BM-MSCs-Exo treatment, the co-localization of NLRP3, ASC, Caspase-1 and the GSDMD translocation from the nucleus to the cytoplasm and membrane after OGD injury were reduced in N2a cells and primary cortical neurons, and H-BM-MSCs-Exo had a more obvious effect. In addition, N-BM-MSCs-Exo and H-BM-MSCs-Exo significantly reduced lactate dehydrogenase (LDH) release and the IL-18 levels in cell culture medium in N2a cells and primary cortical neurons. Once again H-BM-MSCs-Exo induced these effects more potently than N-BM-MSCs-Exo. All of these results demonstrated that N-BM-MSCs-Exo and H-BM-MSCs-Exo have significant neuroprotective effects against NLRP3 inflammasome-mediated pyroptosis. H-BM-MSCs-Exo has a more pronounced protective effect than N-BM-MSCs-Exo and may be used to ameliorate the progression of cerebral ischemia and hypoxia injury in patients.

New epigenetic players in stroke pathogenesis: From non-coding RNAs to exosomal non-coding RNAs

Non-coding RNAs (ncRNAs) have critical role in the pathophysiology as well as recovery after ischemic stroke. ncRNAs, particularly microRNAs, and the long non-coding RNAs (lncRNAs) are critical for angiogenesis and neuroprotection, and they have been suggested to be therapeutic, diagnostic and prognostic tools in cerebrovascular diseases, including stroke. Moreover, exosomes have been considered as nanocarriers capable of transferring various cargos, such as lncRNAs and miRNAs to recipient cells, with prominent inter-cellular roles in the mediation of neuro-restorative events following strokes and neural injuries. In this review, we summarize the pathogenic role of ncRNAs and exosomal ncRNAs in the stroke.

Inhibition of micro RNA miR-122-5p prevents lipopolysaccharide-induced myocardial injury by inhibiting oxidative stress, inflammation and apoptosis via targeting GIT1

Myocardial injury resulting from sepsis is the leading cause of death worldwide. Micro RNA miR-122-5p is involved in various physiological and pathological processes and is highly expressed in the heart of septic rats. However, its function in sepsis-caused myocardial injury remains elusive. Herein, a rat model of septic myocardial injury was established by intraperitoneal injection of lipopolysaccharide (LPS), and cardiomyocyte H9c2 was exposed to LPS to induce sepsis-related inflammatory injury in vitro. Inhibition of miR-122-5p suppressed LPS-triggered myocardial injury evidenced by decreased heart weight index (HWI), reduced inflammatory cell infiltration and cell rupture, and reduced cardiac marker enzymes cTnI and LDH. MiR-122-5p inhibition inhibited ROS production and enhanced the activities of antioxidant enzymes CAT, SOD and GSH-px in LPS-treated rats and H9c2 cells. MiR-122-5p inhibition reduced the production of pro-inflammatory cytokines TNF-α, IL-6 and IL-1β, and inhibited cell apoptosis along with decreased cleaved-caspase 3 induced by LPS. Moreover, increased GIT1 expression was found following miR-122-5p inhibition. We further verified GIT1 as a target of miR-122-5p, and silencing GIT1 partially reversed the benefits of miR-122-5p loss in LPS-injured H9c2 cells. The HO-1 and NQO-1 expression and Nrf-2 activation were enhanced by miR-122-5p inhibition, which was reversed by GIT1 depletion, indicating the involvement of Nrf-2/HO-1 signaling in regulating miR-122-5p/GIT1-mediated cardioprotection. Taken together, our data suggest that inhibition of miR-122-5p may mitigate sepsis-triggered myocardial injury through inhibiting inflammation, oxidative stress and apoptosis via targeting GIT1, which provides a possible therapeutic target for sepsis.

ZNRF2 attenuates focal cerebral ischemia/reperfusion injury in rats by inhibiting mTORC1-mediated autophagy

Zinc and ring finger 2 (ZNRF2), an E3 ubiquitin ligase, plays a crucial role in many diseases. However, its role in cerebral ischemia/reperfusion injury (CIRI) still remains unknown. In this study, the function and molecular mechanism of ZNRF2 in CIRI in vivo and vitro was studied. ZNRF2 was found to be dramatically downregulated in CIRI. Overexpression of ZNRF2 could significantly reduce the neurological deficit, brain infarct volume and histopathological damage of cortex in middle cerebral artery occlusion/reperfusion. Concomitantly, overexpression of ZNRF2 increased the primary neuronal viability and decreased the neuronal apoptosis induced by oxygen-glucose deprivation and reoxygenation (OGD/R). Mechanistically, overexpression of ZNRF2 inhibited the over-induction of autophagy induced by OGD/R which was abolished by mTORC1 inhibitor rapamycin. It can be concluded that ZNRF2 plays a protective effect in CIRI and the underlying mechanism may be related to the inhibition of mTORC1-mediated autophagy.

Matrine regulates H2O2-induced oxidative stress through long non-coding RNA HOTAIR/miR-106b-5p axis via AKT and STAT3 pathways

Matrine is a main active constituent of Chinese herb Sophora flavescens Ait (Kushen), which has shown various pharmacological effects, and has been reported to exhibit protective effects in heart failure. In the present study, the underlying mechanism of matrine was explored in H₂O₂-induced H9c2 cell line. It was confirmed that matrine could alleviate H₂O₂-induced injury in H9c2 cells. And the down-regulation of long non-coding RNA HOTAIR induced by H₂O₂ could be reversed by treating with matrine. Moreover, overexpression of HOTAIR promoted cell viability and superoxide dismutase (SOD) level, but inhibited cell apoptosis and lactate dehydrogenase (LDH) level. We found that miR-106b-5p was a target of HOTAIR and negatively regulated by HOTAIR. Moreover, up-regulation of miR-106b-5p restored the effects of HOTAIR overexpression on cell viability, apoptosis, and the levels of LDH and SOD. In addition, matrine protected H9c2 cells from H₂O₂-induced injury through HOTAIR/miR-106b-5p axis. Furthermore, we discovered that matrine exerted protective effects on H₂O₂-induced H9c2 cells through activating STAT3 and AKT pathway. In brief, matrine modulated H₂O₂-induced myocardial oxidative stress repair through HOTAIR/miR-106b-5p axis via AKT and STAT3 signaling pathway. Our study may provide a therapeutic target for the therapy of oxidative stress heart diseases.

Serum Levels of B-cell Lymphoma-2 Anti-Apoptotic Protein and Malignant Middle Cerebral Artery Infarction Mortality

INTRODUCTION AND GOAL

There is scarce and contradictory data on B-cell lymphoma 2 (Bcl2), member of the Bcl-2 antiapoptotic molecules family of intrinsic apoptosis pathway, in ischemic stroke patients. The objective of this study was to determine whether there is an association between blood Bcl2 concentrations and mortality of ischemic stroke patients.

MATERIAL AND METHODS

Five Intensive Care Units participated in this prospective and observational study of patients with severe malignant middle cerebral artery infarction (MMCAI). Severe MMCAI was diagnosed when acute infarction was present in 50% or more of said region and with a Glasgow Coma Scale (GCS) score of less than 9 points. Serum samples were collected at the time of MMCAI diagnosis.

FINDINGS

Higher serum Bcl2 concentrations (p = 0.001), lower platelet count (p = 0.01) and lower GCS (p = 0.002) were found in non-survivors (n = 28) than in MMCAI survivors (n = 28). Serum Bcl2 levels had an area under the curve for mortality prediction of 75% (95% CI = 62%-88%; p < 0.001). Patients with serum Bcl2 levels > 43.6 ng/mL had higher mortality rate according to Kaplan-Meier analysis (Hazard ratio=10.0; 95% CI = 3.4-29.5; p < 0.001). Multiple logistic regression showed an association between serum Bcl2 and mortality at 30 days (OR = 1.041; 95% CI = 1.006-1.077; p = 0.02) controlling for GCS and platelet count.

CONCLUSIONS

This study reports for the first time the higher blood Bcl2 concentrations in non-surviving ischemic stroke patients than in survivors and the association between elevated blood Bcl2 and mortality in ischemic stroke patients.

MicroRNAs in central nervous system disorders: current advances in pathogenesis and treatment

MicroRNAs (miRNAs) are a class of short, non-coding, regulatory RNA molecules that function as post transcriptional regulators of gene expression. Altered expression of multiple miRNAs was found to be extensively involved in the pathogenesis of different neurological disorders including Alzheimer’s disease, Parkinson’s disease, stroke, epilepsy, multiple sclerosis, amyotrophic lateral sclerosis, and Huntington’s disease. miRNAs are implicated in the pathogenesis of excitotoxicity, apoptosis, oxidative stress, inflammation, neurogenesis, angiogenesis, and blood–brain barrier protection. Consequently, miRNAs can serve as biomarkers for different neurological disorders. In recent years, advances in the miRNA field led to identification of potentially novel prospects in the development of new therapies for incurable CNS disorders. MiRNA-based therapeutics include miRNA mimics and inhibitors that can decrease or increase the expression of target genes. Better understanding of the mechanisms by which miRNAs are implicated in the pathogenesis of neurological disorders may provide novel targets to researchers for innovative therapeutic strategies.

miR-374 improves cerebral ischemia reperfusion injury by targeting Wnt5a

To date, studies have demonstrated the potential functions of microRNAs in cerebral ischemia reperfusion (IR) injury. Herein, we established a middle cerebral artery occlusion (MCAO) model in rats and then subjected them to reperfusion to explore the role of microRNA-374 (miR-374) in cerebral IR injury. After reperfusion, the endogenous miR-374 level decreased, and the expression of its target gene, Wnt5a, increased in brain tissues. Intracerebral pretreatment of miR-374 agomir attenuated cerebral damage induced by IR, including neurobehavioral deficits, infarction, cerebral edema and blood-brain barrier disruption. Moreover, rats pretreated with miR-374 agomir showed a remarkable decrease in apoptotic neurons, which was further confirmed by reduced BAX expression as well as increased BCL-2 and BCL-XL expression. A dual-luciferase reporter assay substantiated that Wnt5a was the target gene of miR-374. miR-374 might protect against brain injury by downregulating Wnt5a in rats after IR. Thus, our study provided a novel mechanism of cerebral IR injury from the perspective of miRNA regulation.

23-Hydroxytormentic acid reduces cerebral ischemia/reperfusion damage in rats through anti-apoptotic, antioxidant, and anti-inflammatory mechanisms

23-Hydroxytormentic acid (23-HTA) is an important herbal medicine purified from immature fruits of African Rubus aceae (Rosaceae). This study was carried out to examine the protection properties and potential mechanisms of 23-HTA against cerebral ischemia/reperfusion (I/R) damage. Rats underwent middle cerebral artery occlusion/reperfusion (MCAO/R) 2/24 h. All animals were euthanized 24 h after reperfusion. Rats were injected with various concentrations of 23-HTA intraperitoneally. Evaluations of infarct volumes, neurological deficit, and brain water contents were carried out to assess the outcome of 23-HTA treatment. The results showed that 23-HTA reduced infarct volumes, brain water content, and neurological deficit in a dosage-dependent manner. 23-HTA can also significantly reduce the numbers of TUNEL-positive cells, the expression levels of Bax, caspase-3, lipid peroxidation, Sod 1, Sod 2, catalase, and pro-inflammatory cytokines TNF and IL-1β and increase the expression levels of Bcl-2 and p-Akt. 23-HTA has a neuroprotective effect due to its anti-apoptotic, antioxidant, and anti-inflammatory effects.

Neurovascular Unit: A critical role in ischemic stroke

Ischemic stroke (IS), a common cerebrovascular disease, results from a sudden blockage of a blood vessel in the brain, thereby restricting blood supply to the area in question, and making a significantly negative impact on human health. Unfortunately, current treatments, that are mainly based on a recanalization of occluded blood vessels, are insufficient or inaccessible to many stroke patients. Recently, the profound influence of the neurovascular unit (NVU) on recanalization and the prognosis of IS have become better understood; in‐depth studies of the NVU have also provided novel approaches for IS treatment. In this article, we review the intimate connections between the changes in the NVU and IS outcomes, and discuss possible new management strategies having practical significance to IS. We discuss the concept of the NVU, as well as its roles in IS blood‐brain barrier regulation, cell preservation, inflammatory immune response, and neurovascular repair. Besides, we also summarize the influence of noncoding RNAs in NVU, and IS therapies targeting the NVU. We conclude that both the pathophysiological and neurovascular repair processes of IS are strongly associated with the homeostatic state of the NVU and that further research into therapies directed at the NVU could expand the range of treatments available for IS.

MicroRNA-670 aggravates cerebral ischemia/reperfusion injury via the Yap pathway

Apoptosis is an important programmed cell death process involved in ischemia/reperfusion injury. MicroRNAs are considered to play an important role in the molecular mechanism underlying the regulation of cerebral ischemia and reperfusion injury. However, whether miR-670 can regulate cell growth and death in cerebral ischemia/reperfusion and the underlying mechanism are poorly understood. In this study, we established mouse models of transient middle artery occlusion and Neuro 2a cell models of oxygen-glucose deprivation and reoxygenation to investigate the potential molecular mechanism by which miR-670 exhibits its effects during cerebral ischemia/reperfusion injury both in vitro and in vivo. Our results showed that after ischemia/reperfusion injury, miR-670 expression was obviously increased. After miR-670 expression was inhibited with an miR-670 antagomir, cerebral ischemia/reperfusion injury-induced neuronal death was obviously reduced. When miR-670 overexpression was induced by an miR-670 agomir, neuronal apoptosis was increased. In addition, we also found that miR-670 could promote Yap degradation via phosphorylation and worsen neuronal apoptosis and neurological deficits. Inhibition of miR-670 reduced neurological impairments after cerebral ischemia/reperfusion injury. These results suggest that microRNA-670 aggravates cerebral ischemia/reperfusion injury through the Yap pathway, which may be a potential target for treatment of cerebral ischemia/reperfusion injury. The present study was approved by the Institutional Animal Care and Use Committee of China Medical University on February 27, 2017 (IRB No. 2017PS035K).

MicroRNA-126a-5p Exerts Neuroprotective Effects on Ischemic Stroke via Targeting NADPH Oxidase 2

BACKGROUND

Ischemic stroke is a destructive cerebrovascular disorder related to oxidative stress; NOX2 is a major source for ROS production; and miR-126a-5p is involved in several diseases, such as abdominal aortic aneurysm. We investigated the role of miR-126a-5p in regulating NOX2 in ischemic stroke.

METHODS

MiR-126a-5p and NOX2 were examined in the brains of rats subjected to cerebral ischemia/reperfusion (I/R) by RT-PCR and Western blot. MiR-126a-5p agomir was delivered to examine the effects of miR-126a-5p on I/R injury. The neurological deficit, infarct volume, and brain water content were evaluated. NOX activity, ROS production, and MDA and SOD levels were detected to assess oxidative stress. H&E staining was used to examine cell state. Apoptosis was evaluated by TUNEL, caspase-3 activity, and cleaved-caspase-3 protein level. The relationship between miR-126a-5p and NOX2 was analyzed by bioinformatics and luciferase reporter assay. MiR-126a-5p mimic, miR-126a-5p inhibitor, or pcDNA-NOX2 were transfected in SH-SY5Y cells to further assess the effects of miR-126a-5p on OGD/R-induced cells injury.

RESULTS

NOX2 was upregulated and miR-126a-5p was down-regulated in the brains of I/R rats. MiR-126a-5p agomir obviously reduced the neurological deficit, infarct volume, brain water content, oxidative stress, and apoptosis in I/R rats. MiR-126a-5p targeted NOX2 directly and regulated NOX2 negatively. Moreover, miR-126a-5p mimic elevated cell viability and inhibited oxidative stress and apoptosis in OGD/R-treated SH-SY5Y cells, while miR-126a-5p inhibitor had the opposite effects. NOX2 overexpression antagonized the protective effects of miR-126a-5p mimic on OGD/R-induced cell injury.

CONCLUSION

MiR-126a-5p is a novel potential target for ischemic stroke therapy due to its protection against cerebral I/R injury via directly targeting NOX2.

Post-transcriptional regulation of frog innate immunity: discovery of frog microRNAs associated with antiviral responses and ranavirus infection using a Xenopus laevis skin epithelial-like cell line

Post-transcriptional regulators such as microRNAs are emerging as conserved regulators of innate antiviral immunity in vertebrates, yet their roles in amphibian antiviral responses remain uncharacterized. We profiled changes in microRNA expressions in the Xenopus laevis skin epithelial-like cell line Xela DS2 in response to poly(I:C)—an analogue of viral double-stranded RNA and inducer of type I interferons—or frog virus 3 (FV3), an immunoevasive virus associated with amphibian mortality events. Small RNA libraries generated from untreated, poly(I:C)-treated, and FV3-infected cells were sequenced. We detected 136 known X. laevis microRNAs and discovered 133 novel X. laevis microRNAs. Sixty-five microRNAs were differentially expressed in response to poly(I:C), many of which were predicted to target regulators of antiviral pathways such as cGAS-STING, RIG-I/MDA-5, TLR signaling, and type I interferon signaling, as well as products of these pathways (NF-ĸB-induced and interferon-stimulated genes). In contrast, only 49 microRNAs were altered by FV3 infection, fewer of which were predicted to interact with antiviral pathways. Interestingly, poly(I:C) treatment or FV3 infection downregulated transcripts encoding factors of the host microRNA biogenesis pathway. Our study is the first to suggest that host microRNAs regulate innate antiviral immunity in frogs and sheds light on microRNA-mediated mechanisms of immunoevasion by FV3.

Vagal Nerve Stimulation Protects Against Cerebral Ischemia-Reperfusion Injury in Rats by Inhibiting Autophagy and Apoptosis

BACKGROUND

Cumulative evidence suggests that neuronal death including autophagy, apoptosis, and necrosis is closely related to the occurrence and development of cerebral ischemia-reperfusion (I/R) injury. Moreover, vagal nerve stimulation (VNS) is involved in many different neuroprotective and neuroplasticity pathways. Thus, VNS may be a novel approach for treating various neurodegenerative diseases. The present study aims to determine whether VNS protects against cerebral I/R injury in rats by inhibiting autophagy and apoptosis.

METHODS

Cerebral I/R injury is induced by middle cerebral artery occlusion (MCAO) and VNS is carried out. Infarct volume, neurological deficit, autophagy, and apoptosis are examined 24 h after reperfusion.

RESULTS

Vagal nerve stimulation decreases infarct volume and suppresses neurological deficit. Moreover, obvious autophagy and apoptosis are detected in rats that have undergone I/R, and VNS inhibits autophagy and apoptosis.

CONCLUSION

Vagal nerve stimulation exerts neuroprotective effects following I/R injury by inhibiting autophagy and apoptosis.

The Effect of Melatonin Modulation of Non-coding RNAs on Central Nervous System Disorders: An Updated Review

Melatonin is a hormone produced in and secreted by the pineal gland. Besides its role in regulating circadian rhythms, melatonin has a wide range of protective functions in the central nervous system (CNS) disorders. The mechanisms underlying this protective function are associated with the regulatory effects of melatonin on related genes and proteins. In addition to messenger ribonucleic acid (RNA) that can be translated into protein, an increasing number of non-coding RNAs in the human body are proven to participate in many diseases. This review discusses the current progress of research on the effects of melatonin modulation of non-coding RNAs (ncRNAs), including microRNA, long ncRNA, and circular RNA. The role of melatonin in regulating common pathological mechanisms through these ncRNAs is also summarized. Furthermore, the ncRNAs, currently shown to be involved in melatonin signaling in CNS diseases, are discussed. The information compiled in this review will open new avenues for future research into melatonin mechanisms and provide a further understanding of ncRNAs in the CNS.

Circular RNA circ_DROSHA alleviates the neural damage in a cell model of temporal lobe epilepsy through regulating miR-106b-5p/MEF2C axis

Temporal lobe epilepsy (TLE) is the most prevalent form of acquired epilepsy. Circular RNAs (circRNAs) have recently been highlighted as important regulators in TLE. Nevertheless, the role and mechanism of circRNA Drosha ribonuclease III (circ_DROSHA) in TLE pathogenesis are still unknown. Magnesium-free extracellular solution was used to establish the TLE cell model. The levels of circ_DROSHA, myocyte-specific enhancer factor 2C (MEF2C) and miR-106b-5p were determined by qRT-PCR and western blot. Cell proliferation was detected by the Cell Counting-8 Kit (CCK-8) assay, and cell apoptosis was measured by flow cytometry. Targeted relationships among circ_DROSHA, miR-106b-5p and MEF2C were confirmed by a dual-luciferase reporter or RNA immunoprecipitation (RIP) assay. Our data showed that circ_DROSHA was down-regulated in the serum samples of TLE patients and the TLE cell model. Circ_DROSHA up-regulation alleviated the cytotoxicity of the TLE cell model by enhancing cell proliferation and repressing cell apoptosis. Circ_DROSHA directly bound to miR-106b-5p. Moreover, miR-106b-5p represented a downstream effector of circ_DROSHA function. MEF2C was a direct target of miR-106b-5p, and miR-106b-5p knockdown relieved magnesium-free treatment-induced cell injury by up-regulating MEF2C. Furthermore, circ_DROSHA regulated MEF2C expression via sponging miR-106b-5p. Our study suggested that the enforced expression of circ_DROSHA alleviated the cell damage of the TLE cell model at least in part through the regulation of the miR-106b-5p/MEF2C axis.

miR-22 protect PC12 from ischemia/reperfusion-induced injury by targeting p53 upregulated modulator of apoptosis (PUMA)

MicroRNAs have been implicated as critical regulatory molecules in many cerebrovascular diseases. Recent studies demonstrated miR-22 might provide a potential neuroprotective effect. However, the neuroprotective effect of miR-22 in ischemia/reperfusion (I/R) injury has not been thoroughly elucidated. In this study, the PC12 cells were subjected to 4 h oxygen and glucose deprivation (I) and 24 h reoxygenation (R). The PC12 cells were pre-transfected with miR-22 or anti-miR-22 or siRNA-mediated downregulation of p53-upregulated-modulator-of-apoptosis (PUMA)(PUMA siRNA) or their controls at 24 h prior to exposure to I/R. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot were employed to analyze mRNA and protein expression. PI and Annexin V assays and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay were used to quantify the rate of apoptosis. We found that miR-22 expression was significantly downregulated in the PC12 cells subjected to I/R. Loss of function of miR-22 increased PC12 apoptosis after I/R, and overexpression of miR-22 decreases PC12 apoptosis after I/R. PUMA protein was upregulated in the I/R group as compared with the sham group. The increased PUMA protein expression and apoptosis induced by I/R was reversed by transfection with PUMA siRNA. We concluded that I/R enhanced apoptosis and PUMA expression in PC12 cells via downregulation of miR-22. Enhanced miR-22 expression reversed both PUMA expression and apoptosis induced by I/R in PC12 cells. miR-22/PUMA axis has important implications for their clinical applications.

Emerging neuroprotective strategies for the treatment of ischemic stroke: An overview of clinical and preclinical studies

Stroke is the leading cause of disability and thesecond leading cause of death worldwide. With the global population aged 65 and over growing faster than all other age groups, the incidence of stroke is also increasing. In addition, there is a shift in the overall stroke burden towards younger age groups, particularly in low and middle-income countries. Stroke in most cases is caused due to an abrupt blockage of an artery (ischemic stroke), but in some instances stroke may be caused due to bleeding into brain tissue when a blood vessel ruptures (hemorrhagic stroke). Although treatment options for stroke are still limited, with the advancement in recanalization therapy using both pharmacological and mechanical thrombolysis some progress has been made in helping patients recover from ischemic stroke. However, there is still a substantial need for the development of therapeutic agents for neuroprotection in acute ischemic stroke to protect the brain from damage prior to and during recanalization, extend the therapeutic time window for intervention and further improve functional outcome. The current review has assessed the past challenges in developing neuroprotective strategies, evaluated the recent advances in clinical trials, discussed the recent initiative by the National Institute of Neurological Disorders and Stroke in USA for the search of novel neuroprotectants (Stroke Preclinical Assessment Network, SPAN) and identified emerging neuroprotectants being currently evaluated in preclinical studies. The underlying molecular mechanism of each of the neuroprotective strategies have also been summarized, which could assist in the development of future strategies for combinational therapy in stroke treatment.

Circular RNA Circ_ANKMY2 Regulates Temporal Lobe Epilepsy Progression via the miR-106b-5p/FOXP1 Axis

Temporal lobe epilepsy (TLE) is common intractable epilepsy that affects the patient's lives. The circular RNA circ_ANKMY2 (circ_ANKMY2) has been reported to be abnormally expressed in TLE. Nevertheless, the role and mechanism of circ_ANKMY2 in TLE are unclear. A human neuroblastoma cell line (SK-N-AS) was used for a series of studies. Expression levels of circ_ANKMY2, miR-106b-5p, and Forkhead Box Protein 1 (FOXP1) mRNA in TLE tissues were assessed through quantitative real-time polymerase chain reaction (qRT-PCR). Cell colony formation, proliferation, and apoptosis were determined by cell colony formation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), or flow cytometry assays. The levels of FOXP1 protein, Ki67, B cell lymphoma (Bcl-2), Bcl-2 Associated X (Bax), and Cleaved caspase-3 were evaluated by western blot analysis. The relationship between circ_ANKMY2 or FOXP1 and miR-106b-5p was verified with dual-luciferase reporter assay. We observed that circ_ANKMY2 and FOXP1 expression were reduced while miR-106b-5p expression was increased in TLE tissues. Overexpression of circ_ANKMY2 decreased spontaneous recurrent seizures (SRSs) in rat TLE model and blocked cell colony formation, proliferation, and induced cell apoptosis in SK-N-AS cells. Importantly, circ_ANKMY2 was verified as a sponge for miR-106b-5p. In addition, miR-106b-5p mimics abolished circ_ANKMY2 elevation-mediated effects on colony formation, proliferation, and apoptosis of SK-N-AS cells. Also, FOXP1 served as a target for miR-106b-5p. And FOXP1 silencing overturned the effects of miR-106b-5p inhibitors on the colony formation, proliferation, and apoptosis of SK-N-AS cells. In sum, circ_ANKMY2 modulated TLE advancement via regulation of FOXP1 expression through sponging miR-106b-5p, and circ_ANKMY2 might be an underlying target for the improvement of TLE.

MicroRNA-124 regulates cell pyroptosis during cerebral ischemia-reperfusion injury by regulating STAT3

Cerebral ischemia-reperfusion injury (CIRI) is the observed continuation and deterioration of ischemic injury, and currently, there are no effective treatment strategies for the condition. It has been reported that microRNAs (miRNAs) serve an important role in CIRI by regulating pyroptosis. The present study demonstrated that miRNA-124 regulated CIRI by regulating STAT3. To explore the relationship between miRNA-124/STAT3 and pyroptosis in CIRI, CIRI was simulated using a middle cerebral artery occlusion model. Subsequently, miRNA-124 expression levels were altered via the intracerebroventricular injection of miRNA-124 agonist or antagonist. The degree of brain tissue injury was assessed by conducting TTC staining and neurological function scoring. Relative miRNA-124 expression levels were determined via reverse transcription-quantitative PCR. A luciferase reporter gene system verified the targeted binding of miRNA-124 to STAT3. The expression levels of key proteins and proinflammatory cytokines associated with pyroptosis [caspase-1, gasdermin D, interleukin (IL)-18 and IL-1β] were detected via western blotting and immunohistochemistry. The increased expression levels of pyroptosis-associated proteins and proinflammatory cytokines in the I/R groups compared with the control group, indicated that pyroptosis intensified over time during CIRI, and miRNA-124 agonist significantly abrogated pyroptosis and improved neurological function compared with the control group. Furthermore, miRNA-124 inhibited STAT3 activation in a targeted manner, which also decreased the extent of pyroptosis. However, miRNA-124 antagonist reversed miR-124 agonist-mediated effects. Therefore, the present study indicated that miRNA-124 may provide neuroprotection against pyroptosis during CIRI, potentially via inhibition of the STAT3 signaling pathway.

Mesenchymal stromal cell-derived extracellular vesicles modulate microglia/macrophage polarization and protect the brain against hypoxia-ischemic injury in neonatal mice by targeting delivery of miR-21a-5p

Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) (MSC-EVs) exhibit protective effects in damaged or diseased tissues. However, the role of EVs secreted by MSC in hypoxia-ischemic (HI) injury in neonatal mice remains unknown. Systemic administration of MSC-EVs attenuated acute brain damage and neuroinflammation, and skewed CD11b⁺/CD45^low microglia and CD11b⁺/CD45^high brain monocyte/macrophage towards a more anti-inflammatory property as determined at 72 h post-HI. In addition, MSC-EVs remarkably improve the injury outcomes pups prior to weaning (P21), while no effect on long-term memory impairment (P42). Importantly, these effects were preceded by incorporation of MSC-EVs into a large number of neurons and microglia within HI group. Abundant levels of miR-21a-5p were present in EVs as determined with next-generation sequencing. Notably, MSC-EVs treatment further increased miR-21a-5p levels at 72 h post HI. Knockdown analyses revealed that miR-21a-5p, and its target-Timp3, were essential for this neuroprotective property of MSC-EVs following HI exposure as demonstrated in both in vitro and in vivo models. These findings suggest that a systemic administration of EVs derived from MSC, have the capacity to incorporated into neurons and microglia where they can then exert neuroprotection against HI-induced injury in neonates through the delivery of miR-21a-5p.

Silencing miR-20a-5p inhibits axonal growth and neuronal branching and prevents epileptogenesis through RGMa-RhoA-mediated synaptic plasticity

Epileptogenesis is a potential process. Mossy fibre sprouting (MFS) and synaptic plasticity promote epileptogenesis. Overexpression of repulsive guidance molecule a (RGMa) prevents epileptogenesis by inhibiting MFS. However, other aspects underlying the RGMa regulatory process of epileptogenesis have not been elucidated. We studied whether RGMa could be modulated by microRNAs and regulated RhoA in epileptogenesis. Using microRNA databases, we selected four miRNAs as potential candidates. We further experimentally confirmed miR‐20a‐5p as a RGMa upstream regulator. Then, in vitro, by manipulating miR‐20a‐5p and RGMa, we investigated the regulatory relationship between miR‐20a‐5p, RGMa and RhoA, and the effects of this pathway on neuronal morphology. Finally, in the epilepsy animal model, we determined whether the miR‐20a‐5p‐RGMa‐RhoA pathway influenced MFS and synaptic plasticity and then modified epileptogenesis. Our results showed that miR‐20a‐5p regulated RGMa and that RGMa regulated RhoA in vitro. Furthermore, in primary hippocampal neurons, the miR‐20a‐5p‐RGMa‐RhoA pathway regulated axonal growth and neuronal branching; in the PTZ‐induced epilepsy model, silencing miR‐20a‐5p prevented epileptogenesis through RGMa‐RhoA‐mediated synaptic plasticity but did not change MFS. Overall, we concluded that silencing miR‐20a‐5p inhibits axonal growth and neuronal branching and prevents epileptogenesis through RGMa‐RhoA‐mediated synaptic plasticity in the PTZ‐induced epilepsy model, thereby providing a possible strategy to prevent epileptogenesis.