Downregulation of LncRNA TUG1 Inhibited TLR4 Signaling Pathway-Mediated Inflammatory Damage After Spinal Cord Ischemia Reperfusion in Rats via Suppressing TRIL Expression

Biochanin A attenuates spinal cord injury in rats during early stages by inhibiting oxidative stress and inflammasome activation

JOURNAL/nrgr/04.03/01300535-202409000-00038/figure1/v/2024-01-16T170235Z/r/image-tiff Previous studies have shown that Biochanin A, a flavonoid compound with estrogenic effects, can serve as a neuroprotective agent in the context of cerebral ischemia/reperfusion injury; however, its effect on spinal cord injury is still unclear. In this study, a rat model of spinal cord injury was established using the heavy object impact method, and the rats were then treated with Biochanin A (40 mg/kg) via intraperitoneal injection for 14 consecutive days. The results showed that Biochanin A effectively alleviated spinal cord neuronal injury and spinal cord tissue injury, reduced inflammation and oxidative stress in spinal cord neurons, and reduced apoptosis and pyroptosis. In addition, Biochanin A inhibited the expression of inflammasome-related proteins (ASC, NLRP3, and GSDMD) and the Toll-like receptor 4/nuclear factor-κB pathway, activated the Nrf2/heme oxygenase 1 signaling pathway, and increased the expression of the autophagy markers LC3 II, Beclin-1, and P62. Moreover, the therapeutic effects of Biochanin A on early post-spinal cord injury were similar to those of methylprednisolone. These findings suggest that Biochanin A protected neurons in the injured spinal cord through the Toll-like receptor 4/nuclear factor κB and Nrf2/heme oxygenase 1 signaling pathways. These findings suggest that Biochanin A can alleviate post-spinal cord injury at an early stage.

The Common LncRNAs of Neuroinflammation-Related Diseases

Spatio-temporal specific long noncoding RNAs (lncRNAs) play important regulatory roles not only in the growth and development of the brain but also in the occurrence and development of neurologic diseases. Generally, the occurrence of neurologic diseases is accompanied by neuroinflammation. Elucidation of the regulatory mechanisms of lncRNAs on neuroinflammation is helpful for the clinical treatment of neurologic diseases. This paper focuses on recent findings on the regulatory effect of lncRNAs on neuroinflammatory diseases and selects 10 lncRNAs that have been intensively studied to analyze their mechanism action. The clinical treatment status of lncRNAs as drug targets is also reviewed. SIGNIFICANCE STATEMENT: Gene therapies such as clustered regularly interspaced short palindrome repeats technology, antisense RNA technology, and RNAi technology are gradually applied in clinical treatment, and the development of technology is based on a large number of basic research investigations. This paper focuses on the mechanisms of lncRNAs regulation of neuroinflammation, elucidates the beneficial or harmful effects of lncRNAs in neurosystemic diseases, and provides theoretical bases for lncRNAs as drug targets.

Comprehensive investigation of the expression profiles of common long noncoding RNAs during microglial activation

Microglia, similar to peripheral macrophages, are the primary immune cells of the central nervous system (CNS). Microglia exist in the resting state in the healthy CNS, but can be activated and polarized into either M1 or M2 subtypes for immune defense and the maintenance of CNS homeostasis by multiple stimuli. Several long noncoding RNAs (lncRNAs) mediate human inflammatory diseases and neuropathologies by regulating their target genes. However, the function of common lncRNAs that contribute to microglial activation remains unclear. Thus, we used bioinformatic approaches to identify common lncRNAs involved in microglial activation in vitro. Our study identified several lncRNAs as common regulators of microglial activation. We identified 283 common mRNAs and 53 common lncRNAs during mouse M1 microglial activation processes, whereas 26 common mRNAs and five common lncRNAs were identified during mouse M2 microglial activation processes. A total of 648 common mRNAs and 274 common lncRNAs were identified during the activation of human M1 microglia. In addition, we identified 1,920 common co-expressed pairs in mouse M1 activation processes and 25 common co-expressed pairs in mouse M2 activation processes. Our study provides a comprehensive understanding of common lncRNA expression profiles in microglial activation processes in vitro. The list of common lncRNAs identified in this study provides novel evidence and clues regarding the molecular mechanisms underlying microglial activation.

MLLT11-TRIL complex promotes the progression of endometrial cancer through PI3K/AKT/mTOR signaling pathway

Endometrial cancer (EC) is a gynecological malignant tumor characterized by high incidence. EC occurrence and development are regulated by numerous molecules and signal pathways. There is a need to explore key regulatory molecules to identify potential therapeutic targets to reduce the incidence of EC. Treatment by targeting a single molecule is characterized by poor efficacy owing to the development of resistance and significant side effects. The current study explored potential candidates in EC by integrating bioinformatics analysis and in vivo and in vitro experimental validation to circumvent the limitation of low efficacy of currently used molecules. Molecular dynamics simulations provide details at the molecular level of intermolecular regulation. In the current study, MLLT11 and TRIL were identified as important regulatory molecules in EC. The two molecules formed a heteromultimer by binding to AKT protein, which induced its phosphorylation of threonine at position 308. Ultimately, the complex stimulates PI3K/AKT/mTOR signaling pathway, a pivotal pathway in tumors. The findings of the current study show a novel complex, MLLT11-TRIL, which can act as AKT protein agonist, thus inducing activity of PI3K/AKT/mTOR signaling pathway. Targeting MLLT11 and TRIL simultaneously, or blocking the formation of the MLLT11-TRIL complex, can abrogate progression of EC.

Asiatic Acid Attenuates Inflammation Induced by Salmonella via Upregulating LncRNA TVX1 in Microglia

Salmonella typhimurium (S.T) induces damage to the central nervous system; however, the role of Asiatic acid (AA) in this is still unknown. Microglia play a role as macrophages to recognize the invaded pathogenic microbes in the brain. The aim of this study was to investigate the protective effect and mechanism of AA on the central nervous system through an in vitro model of S.T infection in microglia. We pre-treated microglia with AA before S.T infection and explored the anti-infection mechanism of AA by sequencing, quantitative reverse transcription PCR (RT-qPCR), and Western blotting. Long non-coding RNA (lncRNA) sequencing demonstrated that inflammation is a major factor in S.T infection of microglia. RT-qPCR data demonstrated that AA inhibited S.T-induced increases in the mRNA levels of the pro-inflammatory factors interleukin (IL)-1β, IL-6, and IL-18. Western blotting demonstrated that AA inhibited S.T-induced activation of the nuclear factor (NF)-κB pathway and activation of the NLR family, pyrin domain-containing 3 (NLRP3) inflammasome. Expression of the lncRNA TVX1 in microglia was decreased by S.T infection and increased by pretreatment with AA. Inhibition of TVX1 expression reversed the anti-inflammatory effect of AA, and overexpression of TVX1 in microglia suppressed S.T-induced inflammation. In conclusion, AA attenuated S.T-induced microglial inflammation by upregulating the expression of the lncRNA TVX1.

Long non-coding RNA H19 contributes to spinal cord ischemia/reperfusion injury through increasing neuronal pyroptosis by miR-181a-5p/HMGB1 axis

Pyroptosis, a programmed inflammatory necrotizing cell death, is likely involved in spinal cord ischemia-reperfusion (SCI/R) injury, but the mechanisms initiating driving neuronal pyroptosis must be further revealed. The aim of this study is to unravel the mechanism of long non-coding RNA (lncRNA) H19 during SCI/R. SCI/R model was induced in C57BL/6 mice by blocking the aortic arch in vivo, and oxygen-glucose deprivation/reperfusion (OGD/R) injury model of PC12 cells was established in vitro. Our results showed that H19 and HMGB1 expression was upregulated, while miR-181a-5p was downregulated in the SCI/R mice and OGD/R-treated PC12 cells. SCI/R induced pathological damage, pyroptosis and inflammation compared with the sham group. H19 acted as a molecular sponge to suppress miR-181a-5p, and HMGB1 was identified as a direct target of miR-181a-5p. MiR-181a-5p overexpression inhibited the increase of IL-1β, IL-18 and TNF-α production and NLRP3, ASC, and Cleaved-caspase-1 expression in OGD/R-treated PC12 cells; while miR-181a-5p silencing exerted opposite effects. HMGB1 overexpression reversed H19 knockdown-mediated the inhibition of pyroptosis and inflammation in OGD/R-treated PC12 cells. In vivo, H19 knockdown promoted the hind limb motor function recovery and alleviated the pathological damage, pyroptosis and inflammation induced by SCI/R. LncRNA H19/miR-181a-5p/HMGB1 pathway contributes to pyroptosis via activating caspase1 signaling during SCI/R, suggesting that this axis may be a potent therapeutic target in SCI/R.

A new perspective on depression and neuroinflammation: Non-coding RNA

The high incidence and relapse rate of depression, as well comorbidity with other diseases, has made depression one of the primary causes of years of life lived with disability. Moreover, the unknown biological mechanism of depression has made treatment difficult. Neuroinflammation is important in the pathogenesis of depression. Neuroinflammation may affect depression by regulating the production of immune factors, immune cell activation, neuron generation, synaptic plasticity, and neurotransmission. Non-coding RNAs (ncRNAs) may be a breakthrough link between depression and neuroinflammation, as ncRNAs participate in these biological changes. We summarize the functions and mechanisms of ncRNAs in neuroinflammation and depression, and predict ncRNAs that may regulate the occurrence and progression of depression through neuritis. These findings not only broaden our understanding of the genetic regulation of depression and neuroinflammation but also provide a new perspective of the underlying mechanism and aid in the design of novel prevention, diagnosis, and treatment strategies.

The Intriguing Role of TLR Accessory Molecules in Cardiovascular Health and Disease

Activation of Toll like receptors (TLR) plays an important role in cardiovascular disease development, progression and outcomes. Complex TLR mediated signaling affects vascular and cardiac function including tissue remodeling and repair. Being central components of both innate and adaptive arms of the immune system, TLRs interact as pattern recognition receptors with a series of exogenous ligands and endogenous molecules or so-called danger associated molecular patterns (DAMPs) that are released upon tissue injury and cellular stress. Besides immune cells, a number of structural cells within the cardiovascular system, including endothelial cells, smooth muscle cells, fibroblasts and cardiac myocytes express TLRs and are able to release or sense DAMPs. Local activation of TLR-mediated signaling cascade induces cardiovascular tissue repair but in a presence of constant stimuli can overshoot and cause chronic inflammation and tissue damage. TLR accessory molecules are essential in guiding and dampening these responses toward an adequate reaction. Furthermore, accessory molecules assure specific and exclusive TLR-mediated signal transduction for distinct cells and pathways involved in the pathogenesis of cardiovascular diseases. Although much has been learned about TLRs activation in cardiovascular remodeling, the exact role of TLR accessory molecules is not entirely understood. Deeper understanding of the role of TLR accessory molecules in cardiovascular system may open therapeutic avenues aiming at manipulation of inflammatory response in cardiovascular disease. The present review outlines accessory molecules for membrane TLRs that are involved in cardiovascular disease progression. We first summarize the up-to-date knowledge on TLR signaling focusing on membrane TLRs and their ligands that play a key role in cardiovascular system. We then survey the current evidence of the contribution of TLRs accessory molecules in vascular and cardiac remodeling including myocardial infarction, heart failure, stroke, atherosclerosis, vein graft disease and arterio-venous fistula failure.

Coding and long non-coding gene expression changes in the CNS traumatic injuries

Traumatic brain injury (TBI) and spinal cord injury (SCI) are two main central nervous system (CNS) traumas, caused by external physical insults. Both injuries have devastating effects on the quality of life, and there is no effective therapy at present. Notably, gene expression profiling using bulk RNA sequencing (RNA-Seq) and single-cell RNA-Seq (scRNA-Seq) have revealed significant changes in many coding and non-coding genes, as well as important pathways in SCI and TBI. Particularly, recent studies have revealed that long non-coding RNAs (lncRNAs) with lengths greater than 200 nucleotides and without protein-coding potential have tissue- and cell type-specific expression pattern and play critical roles in CNS injury by gain- and loss-of-function approaches. LncRNAs have been shown to regulate protein-coding genes or microRNAs (miRNAs) directly or indirectly, participating in processes including inflammation, glial activation, cell apoptosis, and vasculature events. Therefore, lncRNAs could serve as potential targets for the diagnosis, treatment, and prognosis of SCI and TBI. In this review, we highlight the recent progress in transcriptome studies of SCI and TBI and insights into molecular mechanisms.

Blood-Spinal Cord Barrier: Its Role in Spinal Disorders and Emerging Therapeutic Strategies

The blood-spinal cord barrier (BSCB) has been long thought of as a functional equivalent to the blood-brain barrier (BBB), restricting blood flow into the spinal cord. The spinal cord is supported by various disc tissues that provide agility and has different local immune responses compared to the brain. Though physiologically, structural components of the BSCB and BBB share many similarities, the clinical landscape significantly differs. Thus, it is crucial to understand the composition of BSCB and also to establish the cause–effect relationship with aberrations and spinal cord dysfunctions. Here, we provide a descriptive analysis of the anatomy, current techniques to assess the impairment of BSCB, associated risk factors and impact of spinal disorders such as spinal cord injury (SCI), amyotrophic lateral sclerosis (ALS), peripheral nerve injury (PNI), ischemia reperfusion injury (IRI), degenerative cervical myelopathy (DCM), multiple sclerosis (MS), spinal cavernous malformations (SCM) and cancer on BSCB dysfunction. Along with diagnostic and mechanistic analyses, we also provide an up-to-date account of available therapeutic options for BSCB repair. We emphasize the need to address BSCB as an individual entity and direct future research towards it.

Epigenetic Regulations of Microglia/Macrophage Polarization in Ischemic Stroke

Ischemic stroke is one of the leading causes of death and disability worldwide. Microglia/macrophages (MMs)-mediated neuroinflammation contributes significantly to the pathological process of ischemic brain injury. Microglia, serving as resident innate immune cells in the central nervous system, undergo pro-inflammatory phenotype or anti-inflammatory phenotype in response to the microenvironmental changes after cerebral ischemia. Emerging evidence suggests that epigenetics modifications, reversible modifications of the phenotype without changing the DNA sequence, could play a pivotal role in regulation of MM polarization. However, the knowledge of the mechanism of epigenetic regulations of MM polarization after cerebral ischemia is still limited. In this review, we present the recent advances in the mechanisms of epigenetics involved in regulating MM polarization, including histone modification, non-coding RNA, and DNA methylation. In addition, we discuss the potential of epigenetic-mediated MM polarization as diagnostic and therapeutic targets for ischemic stroke. It is valuable to identify the underlying mechanisms between epigenetics and MM polarization, which may provide a promising treatment strategy for neuronal damage after cerebral ischemia.

Emerging roles of long non-coding RNAs in spinal cord injury

Spinal cord injury (SCI) is the most serious complication of spinal injury and often leads to severe dysfunction of the limb below the injured segment. SCI causes not only serious physical and psychological harm to the patients, but imposes an enormous economic burden on the whole society. Great efforts have been made to improve the functional outcomes of patients with SCI; however, therapeutic advances have far been limited. Long non-coding RNA (lncRNA) is an important regulator of gene expression and has recently been characterized as a key regulator of central nervous system stabilization. Emerging evidence suggested that lncRNAs are significantly dysregulated and play a key role in the development of SCI. Our review summarizes current researches regarding the roles of deregulated lncRNAs in modulating apoptosis, inflammatory response, neuronal behavior in SCI. These studies suggest that specific regulation of lncRNA or its downstream targets may provide a new therapeutic approach for this desperate disease.

Non-Coding RNAs: Emerging Therapeutic Targets in Spinal Cord Ischemia-Reperfusion Injury

Paralysis or paraplegia caused by transient or permanent spinal cord ischemia–reperfusion injury (SCIRI) remains one of the most devastating post-operative complications after thoracoabdominal aortic surgery, even though perioperative strategies and surgical techniques continue to improve. Uncovering the molecular and cellular pathophysiological processes in SCIRI has become a top priority. Recently, the expression, function, and mechanism of non-coding RNAs (ncRNAs) in various diseases have drawn wide attention. Non-coding RNAs contain a variety of biological functions but do not code for proteins. Previous studies have shown that ncRNAs play a critical role in SCIRI. However, the character of ncRNAs in attenuating SCIRI has not been systematically summarized. This review article will be the first time to assemble the knowledge of ncRNAs regulating apoptosis, inflammation, autophagy, and oxidative stress to attenuate SCIRI. A better understanding of the functional significance of ncRNAs following SCIRI could help us to identify novel therapeutic targets and develop potential therapeutic strategies. All the current research about the function of nRNAs in SCIRI will be summarized one by one in this review.

Identification of Circular RNAs Related to Vascular Endothelial Proliferation, Migration, and Angiogenesis After Spinal Cord Injury Using Microarray Analysis in Female Mice

Background: Traumatic spinal cord injury (SCI) can result in severe disability and causes a considerable socio-economic burden worldwide. Circular RNAs (circRNAs) are important regulators of gene expression and pathological processes, and may represent therapeutic targets for SCI. To further evaluate the role of circRNAs in SCI, we elucidated circRNA expression profiles related to vascular endothelial proliferation, migration, and angiogenesis during the early stages of secondary injury in a mouse model of SCI.

Methods: Microarray analysis was performed to investigate the circRNA expression patterns in the spinal cord 3 days after SCI in female mice. Bioinformatic analyses, including GO enrichment analysis, KEGG pathway analysis, and circRNA-miRNA-mRNA network construction, were conducted to explore the role of circRNA dysregulation in vascular endothelial proliferation, migration, and angiogenesis following SCI.

Results: The expression of 1,288 circRNAs was altered (>2-fold change, p < 0.05) in the spinal cord after SCI, consisting of 991 upregulated and 297 downregulated circRNAs. We constructed a circRNA-mRNA network to predict whether these circRNAs could act as “miRNA sponges.” We next assessed the association of altered circRNAs with vascular endothelial proliferation, migration, and angiogenesis using GO and KEGG analyses. Using this analysis, we found that a total of 121 circRNAs were correlated with vascular endothelial proliferation, migration, and angiogenesis in the spinal cord after SCI.

Conclusions: Our study provides circRNA expression profiles during the early stages of SCI. circRNA.7079, circRNA.7078, and circRNA.6777 were found to play key roles in the vascular endothelial proliferation, migration, and angiogenesis, and may represent therapeutic targets for SCI.

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

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

TLR4-interactor with leucine-rich repeats (TRIL) is involved in diet-induced hypothalamic inflammation

Obesity and high-fat diet (HFD) consumption result in hypothalamic inflammation and metabolic dysfunction. While the TLR4 activation by dietary fats is a well-characterized pathway involved in the neuronal and glial inflammation, the role of its accessory proteins in diet-induced hypothalamic inflammation remains unknown. Here, we demonstrate that the knockdown of TLR4-interactor with leucine-rich repeats (Tril), a functional component of TLR4, resulted in reduced hypothalamic inflammation, increased whole-body energy expenditure, improved the systemic glucose tolerance and protection from diet-induced obesity. The POMC-specific knockdown of Tril resulted in decreased body fat, decreased white adipose tissue inflammation and a trend toward increased leptin signaling in POMC neurons. Thus, Tril was identified as a new component of the complex mechanisms that promote hypothalamic dysfunction in experimental obesity and its inhibition in the hypothalamus may represent a novel target for obesity treatment.

Icariin, an Up-and-Coming Bioactive Compound Against Neurological Diseases: Network Pharmacology-Based Study and Literature Review

Icariin is a biologically active substance in Epimedii herba that is used for the treatment of neurologic disorders. However, a comprehensive analysis of the molecular mechanisms of icariin is lacking. In this review, we present a brief history of the use of icariin for medicinal purposes; describe the active chemical components of Epimedii herba; and examine the evidence from experimental studies that have uncovered molecular targets of icariin in different diseases. We also constructed a protein–protein interaction network and carried out Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional enrichment analyses to predict the therapeutic actions of icariin in nervous system diseases including Alzheimer disease, Parkinson disease, ischemic stroke, depressive disorder, multiple sclerosis, glioblastoma, and hereditary spastic paraplegias. The results of our analyses can guide future studies on the application of icariin to the treatment of neurologic disorders.

LncRNAs Associated with Neuronal Development and Oncogenesis Are Deregulated in SOD1-G93A Murine Model of Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a devastating neurodegenerative disease caused in 10% of cases by inherited mutations considered “familial”. An ever-increasing amount of evidence is showing a fundamental role for RNA metabolism in ALS pathogenesis, and long non-coding RNAs (lncRNAs) appear to play a role in ALS development. Here, we aim to investigate the expression of a panel of lncRNAs (linc-Enc1, linc–Brn1a, linc–Brn1b, linc-p21, Hottip, Tug1, Eldrr, and Fendrr) which could be implicated in early phases of ALS. Via Real-Time PCR, we assessed their expression in a murine familial model of ALS (SOD1-G93A mouse) in brain and spinal cord areas of SOD1-G93A mice in comparison with that of B6.SJL control mice, in asymptomatic (week 8) and late-stage disease (week 18). We highlighted a specific area and pathogenetic-stage deregulation in each lncRNA, with linc-p21 being deregulated in all analyzed tissues. Moreover, we analyzed the expression of their human homologues in SH-SY5Y-SOD1-WT and SH-SY5Y-SOD1-G93A, observing a profound alteration in their expression. Interestingly, the lncRNAs expression in our ALS models often resulted opposite to that observed for the lncRNAs in cancer. These evidences suggest that lncRNAs could be novel disease-modifying agents, biomarkers, or pathways affected by ALS neurodegeneration.

Long Noncoding RNA Taurine-Upregulated Gene 1 Knockdown Protects Cardiomyocytes Against Hypoxia/Reoxygenation-induced Injury Through Regulating miR-532-5p/Sox8 Axis

BACKGROUND

Long noncoding RNA taurine-upregulated gene 1 (TUG1) has been reported to involve in the processing of cardiac ischemia/reperfusion injury after myocardial infarction. Thus, this study further investigates the underlying mechanisms of TUG1 in hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury in vitro.

METHODS

Cell viability, apoptosis, and migration and invasion were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, and transwell assay, respectively. Western blot was used to examine the levels of matrix metallopeptidase 9, matrix metallopeptidase 2, and sex determining region Y-box transcription factor 8 (Sox8) protein. Levels of lactate dehydrogenase, malondialdehyde, superoxide dismutase, and glutathione peroxidase were detected using commercial kits. Levels of TUG1, microRNA-532-5p (miR-532-5p), and Sox8 were detected by quantitative real-time polymerase chain reaction. The interaction between miR-532-5p and Sox8 or TUG1 was confirmed by dual-luciferase reporter and RNA immunoprecipitation assay.

RESULTS

H/R induced rat cardiomyocyte H9c2 injury by inhibiting cell viability, migration and invasion, promoting cell apoptosis, and stimulating oxidative stress. H/R-induced H9c2 injury upregulated the level of TUG1, and TUG1 knockdown alleviated H/R-induced cardiomyocyte injury. TUG1 directly bound to miR-532-5p, and miR-532-5p inhibition reversed the action of TUG1 knockdown on H/R-induced cardiomyocyte injury. Sox8 was a target of miR-532-5p, and miR-532-5p blunted H/R-induced cardiomyocyte injury by targeting Sox8. In addition, TUG1 knockdown inhibited H/R-induced Sox8 elevation through miR-532-5p in H9c2 cells.

CONCLUSION

TUG1 silence ameliorated H/R-induced cardiomyocytes injury through regulating miR-532-5p/Sox8 axis, suggesting a potential therapeutic target for preventing myocardial ischemia/reperfusion injury.

Long non-coding RNA: An underlying bridge linking neuroinflammation and central nervous system diseases

Central nervous system (CNS) diseases are responsible for a large proportion of morbidity and mortality worldwide. CNS diseases caused by intrinsic and extrinsic stimuli stimulate the resident immune cells including microglia and astrocyte, resulting in neuroinflammation that exacerbates the progression of diseases. Recent evidence reveals the aberrant expression patterns of long non-coding RNAs (lncRNAs) in the damaged tissues following CNS diseases. It was also proposed that lncRNAs possessed immune-modulatory activities by directly or indirectly affecting various effector proteins including transcriptional factor, acetylase, protein kinase, phosphatase, etc. In addition, lncRNAs can form a sophisticated network by interacting with other molecules to regulate the expression or activation of downstream immune response pathways. However, the major roles of lncRNAs in CNS pathophysiologies are still elusive, especially in neuroinflammation. Herein, we tend to review some potential roles of lncRNAs in modulating neuroinflammation based on current evidence in various CNS diseases, in order to provide novel explanations for the initiation and progression of CNS diseases and help to establish therapeutic strategies targeting neuroinflammation.

Identification of key microRNAs and the underlying molecular mechanism in spinal cord ischemia-reperfusion injury in rats

Spinal cord ischemia-reperfusion injury (SCII) is a pathological process with severe complications such as paraplegia and paralysis. Aberrant miRNA expression is involved in the development of SCII. Differences in the experimenters, filtering conditions, control selection, and sequencing platform may lead to different miRNA expression results. This study systematically analyzes the available SCII miRNA expression data to explore the key differently expressed miRNAs (DEmiRNAs) and the underlying molecular mechanism in SCII. A systematic bioinformatics analysis was performed on 23 representative rat SCII miRNA datasets from PubMed. The target genes of key DEmiRNAs were predicted on miRDB. The DAVID and TFactS databases were utilized for functional enrichment and transcription factor binding analyses. In this study, 19 key DEmiRNAs involved in SCII were identified, 9 of which were upregulated (miR-144-3p, miR-3568, miR-204, miR-30c, miR-34c-3p, miR-155-3p, miR-200b, miR-463, and miR-760-5p) and 10 downregulated (miR-28-5p, miR-21-5p, miR-702-3p, miR-291a-3p, miR-199a-3p, miR-352, miR-743b-3p, miR-125b-2-3p, miR-129-1-3p, and miR-136). KEGG enrichment analysis on the target genes of the upregulated DEmiRNAs revealed that the involved pathways were mainly the cGMP-PKG and cAMP signaling pathways. KEGG enrichment analysis on the target genes of the downregulated DEmiRNAs revealed that the involved pathways were mainly the Chemokine and MAPK signaling pathways. GO enrichment analysis indicated that the target genes of the upregulated DEmiRNAs were markedly enriched in biological processes such as brain development and the positive regulation of transcription from RNA polymerase II promoter. Target genes of the downregulated DEmiRNAs were mainly enriched in biological processes such as intracellular signal transduction and negative regulation of cell proliferation. According to the transcription factor analysis, the four transcription factors, including SP1, GLI1, GLI2, and FOXO3, had important regulatory effects on the target genes of the key DEmiRNAs. Among the upregulated DEmiRNAs, miR-3568 was especially interesting. While SCII causes severe neurological deficits of lower extremities, the anti-miRNA oligonucleotides (AMOs) of miR-3568 improve neurological function. Cleaved caspase-3 and Bax was markedly upregulated in SCII comparing to the sham group, and miR-3568 AMO reduced the upregulation. Bcl-2 expression levels showed a opposite trend as cleaved caspase-3. The expression of GATA6, GATA4, and RBPJ decreased after SCII and miR-3568 AMO attenuated this upregulation. In conclusion, 19 significant DEmiRNAs in the pathogenesis of SCII were identified, and the underlying molecular mechanisms were validated. The DEmiRNAs could serve as potential intervention targets for SCII. Moreover, inhibition of miR-3568 preserved hind limb function after SCII by reducing apoptosis, possibly through regulating GATA6, GATA4, and RBPJ in SCII.

Research progress on the regulatory role of microRNAs in spinal cord injury

Spinal cord injury (SCI) is a severe CNS injury that results in abnormalities in, or loss of, motor, sensory and autonomic nervous function. miRNAs belong to a new class of noncoding RNA that regulates the production of proteins and biological function of cells by silencing translation or interfering with the expression of target mRNAs. Following SCI, miRNAs related to oxidative stress, inflammation, autophagy, apoptosis and many other secondary injuries are differentially expressed, and these miRNAs play an important role in the progression of secondary injuries after SCI. The purpose of this review is to elucidate the differential expression and functional roles of miRNAs after SCI, thus providing references for further research on miRNAs in SCI.

Bioinformatics-Based Analysis of the lncRNA-miRNA-mRNA Network and TF Regulatory Network to Explore the Regulation Mechanism in Spinal Cord Ischemia/Reperfusion Injury

Background

Spinal cord ischemia/reperfusion injury (SCII) is a catastrophic complication involved with cardiovascular, spine, and thoracic surgeries and can lead to paraplegia. Nevertheless, the molecular mechanism of SCII remain ill-defined.

Methods

Expression profiling (GSE138966) data were obtained from GEO database. Then, differentially expressed (DE) lncRNAs and DEmRNAs were screened out with p < 0.05, and | fold change| > 1.5. Aberrant miRNAs expression in SCII was obtained from PubMed. Functional enrichment analysis of overlapping DEmRNAs between predicted mRNAs in miRDB database and DEmRNAs obtained from GSE138966 was performed using cluster Profiler R package. The lncRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) network was established in light of ceRNA theory. The key lncRNAs in the ceRNA network were identified by topological analysis. Subsequently, key lncRNAs related ceRNA-pathway network and transcription factors (TFs)-mRNAs network were constructed. Simultaneously, the expression levels of hub genes were measured via qRT-PCR.

Results

The results in this study indicated that 76 miRNAs, 1373 lncRNAs, and 4813 mRNAs were differentially expressed in SCII. A SCII-related ceRNA network was constructed with 154 ncRNAs, 139 mRNAs, and 51 miRNAs. According topological analysis, six lncRNAs (NONRATT019236.2, NONRATT009530.2, NONRATT026999.2, TCONS_00032391, NONRATT023112.2, and NONRATT021956.2) were selected to establish the ceRNA-pathway network, and then two candidate hub lncRNAs (NONRATT009530.2 and NONRATT026999.2) were identified. Subsequently, two lncRNA-miRNA-mRNA regulatory axes were identified. NONRATT026999.2 and NONRATT009530.2 might involve SCII via miR-20b-5p/Map3k8 axis based on the complex ceRNA network. SP1 and Hnf4a acting as important TFs might regulate Map3k8. Furthermore, qRT-PCR results showed that the NONRATT009530.2, NONRATT026999.2, Map3k8, Hfn4a, and SP1 were significantly upregulated in SCII of rats, while the miR-20b-5p was downregulated.

Conclusion

Our results offer a new insight to understand the ceRNA regulation mechanism in SCII and identify highlighted lncRNA-miRNA-mRNA axes and two key TFs as potential targets for prevention and treatment of SCII.

LncRNA TUG1 Demethylated by TET2 Promotes NLRP3 Expression, Contributes to Cerebral Ischemia/Reperfusion Inflammatory Injury

LncRNA TUG1 has not yet been reported in cerebral ischemia/reperfusion (I/R) injury. Methylcytosine dioxygenase TET2 is involved in ischemic damage. This study aimed to investigate the effects of TUG1 demethylated by TET2 on I/R-induced inflammatory response and identified its possible mechanisms.We found that TUG1 expression was significantly upregulated in oxygen-glucose deprivation and reoxygenation (OGD/R)-induced SH-SY5Y and SK-N-SH cells. Using the middle cerebral artery occlusion (MCAO) mice, we observed a similar effect. We also found that I/R injury could downregulate miR-200a-3p and upregulate NLRP3 and TET2. The knockdown of TUG1 could alleviate OGD/R-induced inflammatory response through upregulating miR-200a-3p and downregulating NLRP3 and other pro-inflammatory molecules. miR-200a-3p inhibition can partially reverse the effects of TUG1 silencing. Further experiments confirmed that TUG1 sponged miR-200a-3p to diminish miR-200a-3p and promote NLRP3 dependent inflammatory responses. Mechanically, knockdown of TET2 induced low levels of TUG1 and high levels of miR-200a-3p in both SK-N-SH and SH-SY5Y cells. IL-18, IL-1β, NLRP3, Caspase-1, and GSDMD-N were highly downregulated in OGD/R-induced SK-N-SH and SH-SY5Y cells after TET2 knockdown. TUG1 overexpression could reverse this effect. All the data indicated that TET2 could demethylate TUG1 and contribute to the inflammatory response. In additional experiments using the MCAO mice model, we confirmed knockdown of TET2 attenuated I/R-induced inflammatory response and brain injuries via decreasing TUG1 and increasing miR-200a-3p to inhibit NLRP3 expression. The demethylation of TUG1 by TET2 might aggravate I/R-induced inflammatory injury via modulating NLRP3 by miR-200a-3p. Our data confirmed that TET2 contributed to I/R-induced inflammatory response via the demethylation of TUG1 and regulated TUG1/miR-200a-3p/NLRP3 pathway.

Studies on the Regulatory Roles and Related Mechanisms of lncRNAs in the Nervous System

Long noncoding RNAs (lncRNAs) have attracted extensive attention due to their regulatory role in various cellular processes. Emerging studies have indicated that lncRNAs are expressed to varying degrees after the growth and development of the nervous system as well as injury and degeneration, thus affecting various physiological processes of the nervous system. In this review, we have compiled various reported lncRNAs related to the growth and development of central and peripheral nerves and pathophysiology (including advanced nerve centers, spinal cord, and peripheral nervous system) and explained how these lncRNAs play regulatory roles through their interactions with target-coding genes. We believe that a full understanding of the regulatory function of lncRNAs in the nervous system will contribute to understand the molecular mechanism of changes after nerve injury and will contribute to discover new diagnostic markers and therapeutic targets for nerve injury diseases.

The Expanding Regulatory Mechanisms and Cellular Functions of Long Non-coding RNAs (lncRNAs) in Neuroinflammation

LncRNAs have emerged as important regulatory molecules in biological processes. They serve as regulators of gene expression pathways through interactions with proteins, RNA, and DNA. LncRNA expression is altered in several diseases of the central nervous system (CNS), such as neurodegenerative disorders, stroke, trauma, and infection. More recently, it has become clear that lncRNAs contribute to regulating both pro-inflammatory and anti-inflammatory pathways in the CNS. In this review, we discuss the molecular pathways involved in the expression of lncRNAs, their role and mechanism of action during gene regulation, cellular functions, and use of lncRNAs as therapeutic targets during neuroinflammation in CNS disorders.

Gliadin, through the Activation of Innate Immunity, Triggers lncRNA NEAT1 Expression in Celiac Disease Duodenal Mucosa

Celiac disease (CD) is an autoimmune enteropathy arising in genetically predisposed subjects exposed to gluten, which activates both innate and adaptive immunity. Although the pathogenesis is common to all patients, the clinical spectrum is quite variable, and differences could be explained by gene expression variations. Among the factors able to affect gene expression, there are lncRNAs. We evaluated the expression profile of 87 lncRNAs in CD vs. healthy control (HC) intestinal biopsies by RT-qPCR array. Nuclear enriched abundant transcript 1 (NEAT1) and taurine upregulated gene 1 (TUG1) were detected as downregulated in CD patients at diagnosis, but their expression increased in biopsies of patients on a gluten-free diet (GFD) exposed to gluten. The increase in NEAT1 expression after gluten exposure was mediated by IL-15 and STAT3 activation and binding to the NEAT1 promoter, as demonstrated by gel shift assay. NEAT1 is localized in the nucleus and can regulate gene expression by sequestering transcription factors, and it has been implicated in immune regulation and control of cell proliferation. The demonstration of its regulation by gluten thus also supports the role of lncRNAs in CD and prompts further research on these RNAs as gene expression regulators.

A novel long intergenic non-coding RNA, Nostrill, regulates iNOS gene transcription and neurotoxicity in microglia

BACKGROUND

Microglia are resident immunocompetent and phagocytic cells in the CNS. Pro-inflammatory microglia, stimulated by microbial signals such as bacterial lipopolysaccharide (LPS), viral RNAs, or inflammatory cytokines, are neurotoxic and associated with pathogenesis of several neurodegenerative diseases. Long non-coding RNAs (lncRNA) are emerging as important tissue-specific regulatory molecules directing cell differentiation and functional states and may help direct proinflammatory responses of microglia. Characterization of lncRNAs upregulated in proinflammatory microglia, such as NR_126553 or 2500002B13Rik, now termed Nostrill (iNOS Transcriptional Regulatory Intergenic LncRNA Locus) increases our understanding of molecular mechanisms in CNS innate immunity.

METHODS

Microglial gene expression array analyses and qRT-PCR were used to identify a novel long intergenic non-coding RNA, Nostrill, upregulated in LPS-stimulated microglial cell lines, LPS-stimulated primary microglia, and LPS-injected mouse cortical tissue. Silencing and overexpression studies, RNA immunoprecipitation, chromatin immunoprecipitation, chromatin isolation by RNA purification assays, and qRT-PCR were used to study the function of this long non-coding RNA in microglia. In vitro assays were used to examine the effects of silencing the novel long non-coding RNA in LPS-stimulated microglia on neurotoxicity.

RESULTS

We report here characterization of intergenic lncRNA, NR_126553, or 2500002B13Rik now termed Nostrill (iNOS Transcriptional Regulatory Intergenic LncRNA Locus). Nostrill is induced by LPS stimulation in BV2 cells, primary murine microglia, and in cortical tissue of LPS-injected mice. Induction of Nostrill is NF-κB dependent and silencing of Nostrill decreased inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in BV2 and primary microglial cells. Overexpression of Nostrill increased iNOS expression and NO production. RNA immunoprecipitation assays demonstrated that Nostrill is physically associated with NF-κB subunit p65 following LPS stimulation. Silencing of Nostrill significantly reduced NF-κB p65 and RNA polymerase II recruitment to the iNOS promoter and decreased H3K4me3 activating histone modifications at iNOS gene loci. In vitro studies demonstrated that silencing of Nostrill in microglia reduced LPS-stimulated microglial neurotoxicity.

CONCLUSIONS

Our data indicate a new regulatory role of the NF-κB-induced Nostrill and suggest that Nostrill acts as a co-activator of transcription of iNOS resulting in the production of nitric oxide by microglia through modulation of epigenetic chromatin remodeling. Nostrill may be a target for reducing the neurotoxicity associated with iNOS-mediated inflammatory processes in microglia during neurodegeneration.

LncRNA Airsci increases the inflammatory response after spinal cord injury in rats through the nuclear factor kappa B signaling pathway

Spinal cord injury (SCI) is a serious traumatic event to the central nervous system. Studies show that long non-coding RNAs (lncRNAs) play an important role in regulating the inflammatory response in the acute stage of SCI. Here, we investigated a new lncRNA related to spinal cord injury and acute inflammation. We analyzed the expression profile of lncRNAs after SCI, and explored the role of lncRNA Airsci (acute inflammatory response in SCI) on recovery following acute SCI. The rats were divided into the control group, SCI group, and SCI + lncRNA Airsci-siRNA group. The expression of inflammatory factors, including nuclear factor kappa B [NF-κB (p65)], NF-κB inhibitor IκBα and phosphorylated IκBα (p-IκBα), and the p-IκBα/IκBα ratio were examined 1-28 days after SCI in rats by western blot assay. The differential lncRNA expression profile after SCI was assessed by RNA sequencing. The differentially expressed lncRNAs were analyzed by bioinformatics technology. The differentially expressed lncRNA Airsci, which is involved in NF-κB signaling and associated with the acute inflammatory response, was verified by quantitative real-time PCR. Interleukin (IL-1β), IL-6 and tumor necrosis factor (TNF-α) at 3 days after SCI were measured by western blot assay and quantitative real-time PCR. The histopathology of the spinal cord was evaluated by hematoxylin-eosin and Nissl staining. Motor function was assessed with the Basso, Beattie and Bresnahan Locomotor Rating Scale. Numerous differentially expressed lncRNAs were detected after SCI, including 151 that were upregulated and 186 that were downregulated in the SCI 3 d group compared with the control group. LncRNA Airsci was the most significantly expressed among the five lncRNAs involved in the NF-κB signaling pathway. LncRNA Airsci-siRNA reduced the inflammatory response by inhibiting the NF-κB signaling pathway, alleviated spinal cord tissue injury, and promoted the recovery of motor function in SCI rats. These findings show that numerous lncRNAs are differentially expressed following SCI, and that inhibiting lncRNA Airsci reduces the inflammatory response through the NF-κB signaling pathway, thereby promoting functional recovery. All experimental procedures and protocols were approved by the approved by the Animal Ethics Committee of Jining Medical University (approval No. JNMC-2020-DW-RM-003) on January 18, 2020.

Dexmedetomidine inhibits microglial activation through SNHG14/HMGB1 pathway in spinal cord ischemia-reperfusion injury mice

OBJECTIVE

Microglial activation is an essential pathological mechanism of spinal cord ischemia-reperfusion injury (SCIRI). Previous studies showed dexmedetomidine (DEX) could alleviate SCIRI while the mechanism was not clear. This study aims to investigate the role of DEX in microglial activation and clarify the underlying mechanism.

METHODS

The motion function of mice was quantified using the Basso Mouse Scale for Locomotion. The expression of long non-coding RNA (lncRNA) small nucleolar RNA host gene 14 (SNHG14) was determined by qRT-PCR. The expression of high-mobility group box 1 (HMGB1) was measured by western blot. The activation of microglia was evaluated by the expression of ED-1 and the levels of TNF-α and IL-6. The interplay between SNHG14 and HMGB1 was confirmed with RNA pull-down and RIP assay. The stability of HMGB1 was measured by ubiquitination assay and cycloheximide-chase assay.

RESULTS

DEX inhibited microglial activation and down-regulated SNHG14 expression in SCIRI mice and oxygen and glucose deprivation/reoxygenation (OGD/R)-treated primary microglia. Functionally, SNHG14 overexpression reversed the inhibitory effect of DEX on OGD/R-induced microglial activation. Further investigation confirmed that SNHG14 bound to HMGB1, positively regulated HMGB1 expression by enhancing its stability. In addition, the silence of HMGB1 eliminated the pro-activation impact of SNHG14 overexpression on DEX-treated microglia under the OGD/R condition. Finally, in vivo experiments showed SNHG14 overexpression abrogated the therapeutic effect of DEX on SCIRI mice by up-regulating HMGB1.

CONCLUSION

DEX accelerated HMGB1 degradation via down-regulating SNHG14, thus inhibiting microglial activation in SCIRI mice.

Downregulation of LncRNA Gas5 inhibits apoptosis and inflammation after spinal cord ischemia-reperfusion in rats

Spinal cord ischemia-reperfusion injury(SCII)affects nerve function through many mechanisms, which are complex and not fully understood. Recently, accumulating evidence has indicated that long noncoding RNAs (lncRNAs) play an increasingly important role in SCII. We investigated the role of lncRNA growth arrest-specific 5(Gas5) in a rat SCII model, and its effects on apoptosis and inflammation possibly by modulating MMP-7, cleaved caspase-3 and IL-1β. LncRNA Gas5 and MMP-7 were knocked down by intrathecal siRNA injection. Neurological assessment and TUNEL assay were performed. The RNA and protein expression levels of lncRNA Gas5, MMP-7, cleaved caspase-3 and IL-1β were determined by PCR and Western blotting, respectively. MMP-7 localization was visualized by double-immunofluorescence. SCII induced functional impairment in the hind limb, and the expression of lncRNA Gas5 was highest at 24 h after SCII. LncRNA Gas5 downregulation inhibited the RNA and protein expression of MMP-7, as well as the protein expression of cleaved caspase-3 and IL-1β. LncRNA Gas5 downregulation reduced the number of TUNEL-positive and MMP-7-positive double-labeled cells. Therefore, lncRNA Gas5 downregulation alleviated hind limb functional impairment and improved neuronal apoptosis after SCII. MMP-7 downregulation also inhibited apoptosis and inflammation and alleviated damage. Pretreatment with intrathecal injection of si-lncRNA Gas5 and si-MMP-7 reduced the expression levels of cleaved caspase-3 and IL-1β, protecting nerve function after SCII. These results show that lncRNA Gas5 plays an important role in SCII, perhaps by inhibiting MMP-7, cleaved caspase-3 and IL-1β. LncRNA Gas5 downregulation could be a promising therapeutic approach in the SCII treatment.

Downregulation of Long Noncoding RNA TUG1 Attenuates MTDH-Mediated Inflammatory Damage via Targeting miR-29b-1-5p After Spinal Cord Ischemia Reperfusion

Long noncoding RNAs and microRNAs (miRNAs) play a vital role in spinal cord ischemia reperfusion (IR) injury. The aim of this study was to identify the potential interactions between taurine upregulated gene 1 (TUG1) and miRNA-29b-1-5p in a rat model of spinal cord IR. The IR injury was established by 14-minute occlusion of aortic arch. TUG1 and metadherin (MTDH) knockdown were induced by respective siRNAs, and miR-29b-1-5p expression was modulated using specific inhibitor or mimics. The interactions between TUG1, miR-29b-1-5p, and the target genes were determined using the dual-luciferase reporter assay. We found that IR respectively downregulated and upregulated miR-29b-1-5p and TUG1, and significantly increased MTDH expression. MTDH was predicted as a target of miR-29b-1-5p and its knockdown downregulated NF-κB and IL-1β levels. A direct interaction was observed between TUG1 and miR-29b-1-5p, and knocking down TUG1 upregulated the latter. Furthermore, overexpression of miR-29b-1-5p or knockdown of TUG1 alleviated blood-spinal cord barrier leakage and improved hind-limb motor function by suppressing MTDH and its downstream pro-inflammatory cytokines. Knocking down TUG1 also alleviated MTDH/NF-κB/IL-1β pathway-mediated inflammatory damage after IR by targeting miR-29b-1-5p, whereas blocking the latter reversed the neuroprotective effect of TUG1 knockdown and restored MTDH/NF-κB/IL-1β levels.

Pathophysiological Functions of the lncRNA TUG1

BACKGROUND

Long non-coding RNAs (lncRNAs) with little or no coding capacity are associated with a plethora of cellular functions, participating in various biological processes. Cumulative study of lncRNA provides explanations to the physiological and pathological processes and new perspectives to the diagnosis, prevention, and treatment of some clinical diseases. Long non-coding RNA taurine-upregulated gene 1(TUG1) is one of the first identified lncRNAs associated with human disease, which actively involved in various physiological processes, including regulating genes at epigenetics, transcription, post-transcription, translation, and posttranslation. The aim of this review was to explore the molecular mechanism of TUG1 in various types of human diseases.

METHODS

In this review, we summarized and analyzed the latest findings related to the physiologic and pathophysiological processes of TUG1 in human diseases. The related studies were retrieved and selected the last six years of research articles in PubMed with lncRNA and TUG1 as keywords.

RESULTS

TUG1 is a valuable lncRNA that its dysregulated expression and regulating the biological processes were found in a variety of human diseases. TUG1 is found to exhibit aberrant expression in a variety of malignancies. Dysregulation of TUG1 has been shown to contribute to proliferation, migration, cell cycle changes, inhibited apoptosis, and drug resistance of cancer cells, which revealed an oncogenic role for this lncRNA, but some reports have shown downregulation of TUG1 in lung cancer samples compared with noncancerous samples. In addition, the molecular and biological functions of TUG1 in physiology and disease (relevant to endocrinology, metabolism, immunology, neurobiology) have also been highlighted. Finally, we discuss the limitations and tremendous diagnostic/therapeutic potential of TUG1 in cancer and other diseases.

CONCLUSION

Long non-coding RNA-TUG1 likely served as useful disease biomarkers or therapy targets and effectively applied in different kinds of diseases, such as human cancer and cardiovascular diseases.

LncRNA TUG1 inhibits neuronal apoptosis in status epilepticus rats via targeting the miR-421/mTOR axis

Status epilepticus (SE) induces apoptosis of hippocampal neurons. However, the underlying mechanism in SE is not fully understood. Recently, lncRNA TUG1 is reported as a significant mediator in neuronal development. In present study, we aimed to investigate whether lncRNA TUG1 induces apoptosis of hippocampal neurons in SE rat models. TUG1 expression in serum of normal volunteers and SE patients, SE rats and neurons with epileptiform discharge was detected. SE rat model was established and intervened with TUG1 to evaluate hippocampal neuronal apoptosis. The experiments in vitro were further performed in neurons with epileptiform discharge to verify the effects of TUG1 on neuronal apoptosis of SE rats. The downstream mechanism of TUG1 was predicted and verified. miR-421 was intervened to perform the rescue experiments. Levels of oxidative stress and inflammation-related factors and mTOR pathway-related proteins in SE rats and hippocampal neurons were detected. TUG1 was highly expressed in serum of SE patients, SE rats and neurons with epileptiform discharge. Inhibition of TUG1 relieved pathological injury, oxidative stress and inflammation and reduced neuronal apoptosis in SE rats, which were further verified in hippocampal neurons. TUG1 upregulated TIMP2 expression by targeting miR-421. Overexpressed miR-421 inhibited hippocampal neuronal apoptosis. TUG1 knockout inactivated the mTOR pathway via the miR-421/TIMP2 axis to relieve neuronal apoptosis, oxidative stress and inflammation in SE rats and hippocampal neurons. Taken together, these findings showed that downregulation of lncRNA TUG1 inhibited apoptosis of hippocampal neurons in SE rats, and attenuated oxidative stress and inflammation damage through regulating the miR-421/mTOR axis.

Non-coding RNAs participate in the ischemia-reperfusion injury

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

LncRNA CCAT1 Protects Astrocytes Against OGD/R-Induced Damage by Targeting the miR-218/NFAT5-Signaling Axis

Spinal cord injury (SCI) is a grievous neurology-related disorder that causes many devastating symptoms. Emerging roles of long non-coding RNAs (lncRNA) have been shown to play critical roles in multiple neurological diseases. This research planned to dig the function and latent molecular mechanisms of the lncRNA CCAT1 on OGD/R-disposed injury in astrocytes. We observed that CCAT1 expression was diminished and miR-218 expression was elevated in astrocytes during OGD/R. Additionally, an abundance of CCAT1 obviously amplified cell viability and restrained OGD/R-triggered apoptosis in astrocytes, as characterized by reduced levels of pro-apoptotic proteins Bax and C-caspase-3, concomitant with elevated level of anti-apoptotic Bcl-2 protein. Furthermore, administration of CCAT1 remarkably mitigated OGD/R injury-induced neuro-inflammatory responses, reflected in a reduction of inflammatory cytokines including TNF-α, IL-1β, and IL-6. In action, CCAT1 served as an endogenous sponge effectively downregulating miR-218 expression by binding directly to it, and a negative regulatory relationship between miR-218 and NFAT5. Mechanistically, introduction of miR-218 reversed the inhibitory effects of CCAT1 on OGD/R-induced apoptosis and inflammation damage, which directly resulted from the inhibition of miR-218 and its targeting of NFAT5. Collectively, our study illuminated a new CCAT1/miR-218/NFAT5 regulatory axis in which CCAT1 served as a competing endogenous RNA by sponging miR-218, effectively upregulating NFAT5 expression, thereby alleviating apoptosis and inflammation damage under OGD/R condition. CCAT1 is, therefore, a putative therapeutic target for SCI, based on the results of this study and the potential application of CCAT1 as a neuroprotective agent.

lncRNA TUG1 regulates ulcerative colitis through miR-142-5p/SOCS1 axis

Ulcerative colitis (UC) is a long-lasting inflammation disease which finally results in ulcer of the colon and rectum. The long non-coding RNA (lncRNA) TUG1 has been described to target miR-142 and regulate its expression. In current study, we evaluated the effects of long non-coding RNA TUG1 on cell injury and inflammatory cytokine production using a TNFα-treated HT-29 cells model. We monitored the level of TUG1 in colonic mucosa tissue of UC patients and in TNF-α-treated HT-29 cells. We investigated the effects of TUG1 on miR-142-5p and SOCS1expression, cell viability, lactate dehydrogenase (LDH) release, production of nitrite and PGE2 after TNF-α treatment in HT-29 cells. We also investigated the effects of TUG1 on TNF-α-induced IL-6, IL-8 and IL-1β expression in HT-29 cells. We detected down-regulated TUG1 level in colonic mucosa tissue of UC patients and in TNF-α-treated HT-29 cells. Overexpression of TUG1 enhanced cell viability, decreased LDH release, decreased nitrite and PGE2 production after TNF-α treatment in HT-29 cells. TUG1 prevented IL-1β, IL-6 and IL-8 production in TNF-α-treated cells. TUG1 targeted miR-142-5p and inhibited its expression while enhanced SOCS1 expression. Overexpression of miR-142-5p abolished TUG1-mediated inhibition of TNF-induced inflammatory cytokines production. TUG1 negatively regulated inflammation in ulcerative colitis through miR-142-5p/SOCS1 axis.

Altered expression of MiR-186-5p and its target genes after spinal cord ischemia-reperfusion injury in rats

Spinal cord ischemia-reperfusion (I/R) injury remains an unresolved problem, and the mechanism is not fully elaborated. In a rat model of spinal cord I/R injury, we performed microarray analysis to examine the altered expression of microRNAs (miRs) at 24 h after the modelling. miR-186-5p was chosen for further study. An miR mimic or anti-miR oligonucleotide was intrathecally infused before the surgical procedure. The participation of miR-186-5p and its potential target genes based on bioinformatics analysis were analysed next. Pre-treatment with the miR-186-5p mimic improved neurological function and histological assessment scores; reduced Evans Blue extravasation; attenuated spinal cord oedema; and decreased interleukin 15 (IL-15), IL-6, IL-1β, and tumour necrosis factor-α (TNF-α) expression at 24 h after the modelling. KEGG analysis showed that the group of potential target genes of miR-186-5p was notably enriched in several signalling cascades, such as the Wnt, Hippo, and PI3K-AKT pathways. Gene Ontology (GO) analysis revealed that the group of potential target genes of miR-186-5p was significantly enriched in several biological processes, such as 'Wnt signalling pathway', 'regulation of inflammatory response', and 'Toll-like receptor signalling pathway'. We further found that Wnt5a, TLR3, and chemokine (C-X-C motif) ligand 13 (CXCL13) were upregulated after the modelling and the miR-186-5p mimic reduced the induction of the aforementioned target genes. These data provide evidence that upregulation of miR-186-5p improves neurological outcomes induced by spinal cord I/R injury and may inhibit neuroinflammation through Wnt5a-, TLR3-, or CXCL13-mediated signal pathway in spinal cord I/R injury.

The Emerging Role of lncRNAs in Spinal Cord Injury

Spinal cord injury (SCI) is a highly debilitating disease and is increasingly being recognized as an important global health priority. However, the mechanisms underlying SCI have not yet been fully elucidated, and effective therapies for SCI are lacking. Long noncoding RNAs (lncRNAs), which form a major class of noncoding RNAs, have emerged as novel targets for regulating several physiological functions and mediating numerous neurological diseases. Notably, gene expression profile analyses have demonstrated aberrant changes in lncRNA expression in rats or mice after traumatic or nontraumatic SCI. LncRNAs have been shown to be associated with multiple pathophysiological processes following SCI including inflammation, neural apoptosis, and oxidative stress. They also play a crucial role in the complications associated with SCI, such as neuropathic pain. At the same time, some lncRNAs have been found to be therapeutic targets for neural stem cell transplantation and hydrogen sulfide treatment aimed at alleviating SCI. Therefore, lncRNAs could be promising biomarkers for the diagnosis, treatment, and prognosis of SCI. However, further researches are required to clarify the therapeutic effects of lncRNAs on SCI and the mechanisms underlying these effects. In this study, we reviewed the current progress of the studies on the involvement of lncRNAs in SCI, with the aim of drawing attention towards their roles in this debilitating condition.

The roles of chemokine (C-X-C motif) ligand 13 in spinal cord ischemia-reperfusion injury in rats

Spinal cord ischemia-reperfusion injury (SCII) remains an unresolved complication and its underlying mechanism has not been fully elucidated. In this study, we studied the role of chemokine (C-X-C motif) ligand 13 (CXCL13) in a rat model of SCII. We examined the time course and cellular distribution of CXCL13 protein in rats after SCII. The effects of siRNA targeting CXCL13 or C-X-C chemokine receptor type 5 (CXCR5) in SCII were also investigated. Neurological function, histological assessment, and disruption of the blood-spinal cord barrier (BSCB) were evaluated. The expression levels of CXCL13, CXCR5, phosphorylated extracellular signal-regulated kinase (p-ERK), caspase-3, interleukin 6 (IL-6), TNF-α, and IL-1β were determined. We found that SCII resulted in impaired hind limb function and increased the expression of CXCL13. In addition, CXCL13 expression demonstrated the most pronounced effect at 24 h after SCII. We reveal that CXCL13 protein was co-expressed with the mature neuron marker NeuN and the microglial marker IBA-1 in spinal cord tissues of model rats. SCII also increased the expression of CXCR5, p-ERK, caspase-3, IL-6, TNF-α, and IL-1β at 24 h after SCII. Pre-treatment with CXCL13 siRNA protected the rats against SCII and decreased the expression of signalling pathway proteins and proinflammatory cytokines mentioned above. CXCR5 siRNA also showed similar protective effects. These findings indicate that CXCL13 is involved in SCII. The CXCL13/CXCR5 axis promotes the development of SCII, possibly via ERK-mediated pathways. Targeting the mechanism of CXCL13 involved in the development of SCII might be a potential approach for the treatment of this condition.