Noncoding RNA Myocardial Infarction-associated Transcript Research Articles

Diagnostic significance of LncRNA MIAT in periodontitis and the molecular mechanisms influencing periodontal ligament fibroblasts via the miR-204-5p/DKK1 axis

ObjectiveThis study investigated the clinical importance of long noncoding RNA myocardial infarction-associated transcript (MIAT) in periodontitis and its impact on the functional regulation of human periodontal ligament fibroblasts (hPDLFs). MethodsNinety-eight periodontitis patients and 74 healthy controls were enrolled. In vitro cellular models were created using Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) to stimulate hPDLFs. Real-time quantitative polymerase chain reaction was used to measure mRNA levels of MIAT and osteogenic factors. Inflammation factor concentration was assessed using an enzyme-linked immunosorbent assay. Cell viability and apoptosis were examined by cell counting kit −8 and flow cytometry assay. The targeting relationship was verified by the dual-luciferase reporter and RNA Immunoprecipitation assay. ResultsHighly expressed MIAT and Dicckopf-1 (DDK1), and lowly expressed miR-204–5p were found in the gingival crevicular fluid of periodontitis patients and Pg-LPS induced hPDLFs. MIAT has a sensitivity of 76.53 % and a specificity of 86.49 % for identifying patients with periodontitis among healthy individuals. MIAT acts as a sponge for miR-204–5p and upregulates DDK1 mRNA expression. Silencing of MIAT diminished the promotion of apoptosis and inflammation in hPDLFs by Pg-LPS and enhanced osteogenic differentiation. However, a miR-204–5p inhibitor significantly reversed the effect of silenced MIAT. ConclusionsMIAT may act as a promising biomarker for periodontitis. It modulates apoptosis, inflammation, and osteogenic differentiation of PDLFs by focusing on the miR-204–5p/DKK1 axis, indicating its potential as a new therapeutic target for treating periodontitis.

Hypoxia triggers cardiomyocyte apoptosis via regulating the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis

Long-time hypoxia induced cardiomyocyte apoptosis is an important mechanism of myocardial ischemia (MI) injury. Interestingly, long noncoding RNA myocardial infarction-associated transcript (LncMIAT) has been involved in the regulation of MI injury; however, the underlying mechanism by which LncMIAT affects the progression of hypoxia-induced cardiomyocyte apoptosis remains unclear. In the present study, hypoxia was found to promote cardiomyocyte apoptosis through an increased expression of LncMIAT in vitro. Biological investigations and dual-luciferase gene reporter assay further revealed that LncMIAT was able to bind with miR-708-5p to upregulate the p53-mediated cell death of the cardiomyocytes. Silencing of LncMIAT or overexpression of miR-708-5p led to a significant reduction in p53-mediated cardiomyocyte apoptosis. The methylated RNA immunoprecipitation (MeRIP)-qPCR results showed that hypoxia exerted its effects on LncMIAT through AKLBH5-N6-methyladenosine (m6A) methylation and therefore hypoxia was shown to trigger HL-1 cardiomyocyte apoptosis via the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis. Silencing of AKLBH5 significantly alleviated the m6A methylation-mediated LncMIAT upregulation and p53-mediated cardiomyocyte apoptosis, while promoted miR-708-5p expression. Taken together, the present study highlighted that LncMIAT could act as a key biological target during hypoxia-induced cardiomyocyte apoptosis. In addition, it was shown that hypoxia could promote cardiomyocyte apoptosis through regulation of the m6A methylation-mediated LncMIAT/miR-708-5p/p53 signaling axis.

LncRNA Myocardial Infarction-Associated Transcript (MIAT)/miR-505-5p Axis Regulates Proliferation and Migration of Vascular Smooth Muscle Cells of Hypertension Mice

To clarify the role of long non-coding RNA (lncRNA) MIAT in regulating proliferative and migratory abilities in VSMCs extracted from hypertension mice via downregulating microRNA-505-5p (miR-505-5p). Serum levels of MIAT and miR-505-5p in enrolled 20 hypertension patients and 20 healthy volunteers were detected. VSMCs were extracted from hypertension mice and healthy mice. Regulatory effects of MIAT and miR-505-5p on proliferative and migratory abilities in VSMCs were examined. At last, the interaction between MIAT and miR-505-5p was explored by dual-luciferase reporter assay and rescue experiments. Serum level of MIAT was higher in hypertension patients than those of healthy subjects, while miR-505-5p was downregulated. MIAT level was negatively correlated to miR-505-5p level in serum of hypertension patients. Knockdown of MIAT suppressed proliferative and migratory abilities in VSMCs extracted from hypertension mice. In addition, knockdown of MIAT upregulated E-cadherin and downregulated Vimentin and Snail-1. MiR-505-5p was verified to be the target binding MIAT. Knockdown of miR-505-5p reversed regulatory effects of MIAT on VSMCs phenotypes. LncRNA MIAT stimulates VSMCs in hypertension mice to proliferate and migrate through downregulating miR-505-5p, which may be a promising target for diagnosis and treatment of hypertension.

Long noncoding RNA MIAT regulates TP53 ubiquitination and expedites prostate adenocarcinoma progression by recruiting TBL1X

Despite recent advances in cancer immunotherapy, their efficacy for treating patients with prostate adenocarcinoma (PRAD) is low due to complex immune evasion mechanisms. However, the function of long non-coding RNA (lncRNAs) in immune evasion has not been fully clarified. This study aimed to expound the role of myocardial infarction-associated transcript (MIAT), a lncRNA significantly upregulated in three PRAD-associated datasets, in immune evasion and try to reveal the potential mechanism. MIAT was highly expressed in PRAD tissues and predicted poor prognosis, and suppression of MIAT inhibited the malignant biological behavior of PRAD cells. Moreover, the depletion of MIAT promoted the immune response of CD8+ T cells and hampered the immune evasion of PRAD cells. In addition, MIAT downregulated TP53 protein expression by recruiting transducin beta-like protein 1X (TBL1X) for ubiquitination modification. Silencing of TP53 or overexpression of TBL1X was enough to abate the tumor suppressive effects of MIAT knockdown in vitro and in vivo. Our results provide evidence for a novel regulation mechanism of CD8+ T cells in PRAD and MIAT may serve as a potential therapeutic target in PRAD.

LncRNA-MIAT activates hepatic stellate cells via regulating Hippo pathway and epithelial-to-mesenchymal transition

Long non-coding RNA-myocardial infarction-associated transcript (lncRNA-MIAT) has been reported to play an important role in the development of multiple cancers. However, the biological roles of MIAT in liver fibrosis are still unknown. In this study, the expression of MIAT is up-regulated during liver fibrosis. Silencing MIAT leads to the suppression of hepatic stellate cell (HSC) proliferation and collagen expression. Double immunofluorescence analysis additionally demonstrates that MIAT inhibition leads to the suppression of type I collagen and α-SMA in vitro. In vivo, MIAT knockdown contributes to the inhibition of fibrosis progression and collagen accumulation. MIAT is confirmed as a target of miR-3085-5p, and the co-location of MIAT and miR-3085-5p is found in HSC cytoplasm. Interestingly, there is a negative correlation between MIAT expression and miR-3085-5p level in cirrhotic patients as well as activated HSCs. In addition, the effects of MIAT inhibition on HSC inactivation are blocked down by miR-3085-5p inhibitor. YAP is a target of miR-3085-5p. Reduced YAP caused by loss of MIAT is reversed by miR-3085-5p inhibitor. Notably, YAP knockdown results in the suppression of MIAT-mediated epithelial-to-mesenchymal transition (EMT) process. In conclusion, we demonstrate that MIAT enhances the activation of HSCs, at least in part, via miR-3085-5p/YAP/EMT signaling pathway.

Knockdown of long noncoding RNA MIAT attenuates hypoxia-induced cardiomyocyte injury by regulating the miR-488-3p/Wnt/β-catenin pathway.

Dysfunction of cardiomyocytes contributes to the development of acute myocardial infarction (AMI). Nonetheless, the regulatory mechanism of lncRNA myocardial infarction-associated transcript (MIAT) in cardiomyocyte injury remains largely unclear. The cardiomyocyte injury was assessed via cell viability and apoptosis using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and flow cytometry, respectively. The levels of MIAT, microRNA (miR)-488-3p, and Wnt5a were detected via quantitative real-time polymerase chain reaction and Western blot. After bioinformatical analysis, the binding between miR-488-3p and MIAT or Wnt5a was confirmed via dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays. Our results showed that MIAT expression was increased in AC16 cells after hypoxia treatment. Silencing of MIAT alleviated hypoxia-induced viability reduction, apoptosis increase, and Wnt/β-catenin pathway activation. MIAT directly targeted miR-488-3p. MiR-488-3p might repress hypoxia-induced cardiomyocyte injury, and its knockdown reversed the effect of MIAT depletion on cardiomyocyte injury. Wnt5a was validated as a target of miR-488-3p. Wnt5a expression restoration attenuated the influence of MIAT knockdown on hypoxia-triggered cardiomyocyte injury. Our findings demonstrated that downregulation of MIAT might mitigate hypoxia-induced cardiomyocyte injury partly through miR-488-3p mediated Wnt/β-catenin pathway.

Clinicopathologic and prognostic significance of long non-coding RNA myocardial infarction-associated transcript in multiple cancers.

The aim of the meta-analysis was to explore the clinicopathological and prognostic significance of long non-coding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) in various cancers. We searched multiple databases, including PubMed, China National Knowledge 53 Infrastructure (CNKI), Springer, Web of Science, and Cochrane, for articles on the prognostic value of lncRNA MIAT in various cancers before 25 March 2021. The odds ratio (OR) and 95% confidence interval (CI) were adopted to evaluate the clinicopathological features and outcomes of cancers. The Cancer Genome Atlas dataset was used to identify the differential expression and prognostic significance of lncRNA MIAT. We enrolled 14 publications, including 1,573 cancer patients. Higher lncRNA MIAT expression was significantly related to worse overall survival (OR=3.13, 95% CI: 2.47-3.96, p<0.05), regardless of cancer types, sample size, and follow-up time of the included studies. Additionally, higher lncRNA MIAT expression was associated with larger tumour sizes (OR=1.67, 95% CI: 1.24-2.26, p<0.05), advanced clinical stage (OR=4.79, 95% CI: 3.38-6.79, p<0.05), lymph nodes metastasis (OR=7.33, 95% CI: 4.61-11.67, p<0.05), and distant metastasis (OR=2.62, 95% CI: 1.88-3.66, p<0.05), but not associated with age and gender. We found no publication bias, and sensitivity analysis indicated that the results were reliable. Higher lncRNA MIAT expression may predict larger tumour sizes, advanced clinical stage, metastasis of cancers, and lower overall survival rate. LncRNA MIAT may serve as a useful clinicopathological and prognostic biomarker for cancers.

Long Intergenic Noncoding RNA MIAT as a Regulator of Human Th17 Cell Differentiation.

T helper 17 (Th17) cells protect against fungal and bacterial infections and are implicated in autoimmunity. Several long intergenic noncoding RNAs (lincRNA) are induced during Th17 differentiation, however, their contribution to Th17 differentiation is poorly understood. We aimed to characterize the function of the lincRNA Myocardial Infarction Associated Transcript (MIAT) during early human Th17 cell differentiation. We found MIAT to be upregulated early after induction of human Th17 cell differentiation along with an increase in the chromatin accessibility at the gene locus. STAT3, a key regulator of Th17 differentiation, directly bound to the MIAT promoter and induced its expression during the early stages of Th17 cell differentiation. MIAT resides in the nucleus and regulates the expression of several key Th17 genes, including IL17A, IL17F, CCR6 and CXCL13, possibly by altering the chromatin accessibility of key loci, including IL17A locus. Further, MIAT regulates the expression of protein kinase C alpha (PKCα), an upstream regulator of IL17A. A reanalysis of published single-cell RNA-seq data showed that MIAT was expressed in T cells from the synovium of RA patients. Our results demonstrate that MIAT contributes to human Th17 differentiation by upregulating several genes implicated in Th17 differentiation. High MIAT expression in T cells of RA patient synovia suggests a possible role of MIAT in Th17 mediated autoimmune pathologies.

Long Noncoding RNA MIAT Regulates Hyperosmotic Stress-Induced Corneal Epithelial Cell Injury via Inhibiting the Caspase-1-Dependent Pyroptosis and Apoptosis in Dry Eye Disease.

PurposeThe biological role and mechanism of long noncoding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) in dry eye remain to be illustrated. Pyroptosis is a noticeable form of inflammatory activation, which is characteristic of gasdermin D (GSDMD)-driven cell death. The present study was designed to explore the role of MIAT in pyroptosis and apoptosis induced by hyperosmolarity stress (HS) in human corneal epithelial cells (HCECs).MethodsHCECs were cultured in 70–120 mM hyperosmotic medium for 24 h to create a dry eye model in vitro. The level of the pyroptosis marker GSDMD was measured, and the cell inflammatory response was evaluated by detecting IL-1β and IL-18 levels. Exogenous caspase-1 inhibitor Ac-YVAD-CHO was used. The pyroptosis in HCECs was examined by caspase-1 activity, immunofluorescent staining, and Western blotting. Flow cytometry was performed to test the apoptosis rate of HCECs. Cell migration and proliferation were detected. The expression of the lncRNA MIAT in HCECs was detected by quantitative real-time PCR. MIAT was knocked down by small interfering RNA (siRNA) transfection. The effects of caspase-1 inhibition on pyroptosis, apoptosis, migration, and proliferation were observed.ResultsHS promoted pyroptosis in HCECs by elevating caspase-1, GSDMD, and the active cleavage of GSDMD (N-terminal domain, N-GSDMD), and increased the release of IL-1β, IL-18, LDH and the rate of apoptosis, with reduced cell migration. These changes were prevented by the inhibition of caspase-1. The expression of MIAT was significantly increased in HCECs exposed to a hyperosmotic medium. Silencing MIAT increased the expression of GSDMD, caspase-1, and inflammatory chemokines IL-1β and IL-18, and promoted apoptosis while inhibiting migration and proliferation in HCECs.ConclusionThe lncRNA MIAT is involved in HS-induced pyroptosis and apoptosis and the inflammatory response of HCECs and provides a new understanding of the pathogenesis of dry eye.

MiR-150 Attenuates Maladaptive Cardiac Remodeling Mediated by Long Noncoding RNA MIAT and Directly Represses Profibrotic Hoxa4.

MicroRNA-150 (miR-150) plays a protective role in heart failure (HF). Long noncoding RNA, myocardial infarction-associated transcript (MIAT) regulates miR-150 function in vitro by direct interaction. Concurrent with miR-150 downregulation, MIAT is upregulated in failing hearts, and gain-of-function single-nucleotide polymorphisms in MIAT are associated with increased risk of myocardial infarction (MI) in humans. Despite the correlative relationship between MIAT and miR-150 in HF, their in vivo functional relationship has never been established, and molecular mechanisms by which these 2 noncoding RNAs regulate cardiac protection remain elusive. We use MIAT KO (knockout), Hoxa4 (homeobox a4) KO, MIAT TG (transgenic), and miR-150 TG mice. We also develop DTG (double TG) mice overexpressing MIAT and miR-150. We then use a mouse model of MI followed by cardiac functional, structural, and mechanistic studies by echocardiography, immunohistochemistry, transcriptome profiling, Western blotting, and quantitative real-time reverse transcription-polymerase chain reaction. Moreover, we perform expression analyses in hearts from patients with HF. Lastly, we investigate cardiac fibroblast activation using primary adult human cardiac fibroblasts and in vitro assays to define the conserved MIAT/miR-150/HOXA4 axis. Using novel mouse models, we demonstrate that genetic overexpression of MIAT worsens cardiac remodeling, while genetic deletion of MIAT protects hearts against MI. Importantly, miR-150 overexpression attenuates the detrimental post-MI effects caused by MIAT. Genome-wide transcriptomic analysis of MIAT null mouse hearts identifies Hoxa4 as a novel downstream target of the MIAT/miR-150 axis. Hoxa4 is upregulated in cardiac fibroblasts isolated from ischemic myocardium and subjected to hypoxia/reoxygenation. HOXA4 is also upregulated in patients with HF. Moreover, Hoxa4 deficiency in mice protects the heart from MI. Lastly, protective actions of cardiac fibroblast miR-150 are partially attributed to the direct and functional repression of profibrotic Hoxa4. Our findings delineate a pivotal functional interaction among MIAT, miR-150, and Hoxa4 as a novel regulatory mechanism pertinent to ischemic HF.

Long non-coding RNA myocardial infarction-associated transcript promotes 1-Methyl-4-phenylpyridinium ion-induced neuronal inflammation and oxidative stress in Parkinson’s disease through regulating microRNA-221-3p/ transforming growth factor /nuclear factor E2-related factor 2 axis

ABSTRACT This study attempted to evaluate the role of long non-coding RNA myocardial infarction-associated transcript (LncRNA MIAT) in Parkinson’s disease (PD). The mouse model was established through intraperitoneal injection with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and in vitro model was induced by administrating cell with 1-Methyl-4-phenylpyridinium ion (MPP+). Rotarod test was conducted to evaluate the motor coordination of PD mice. In order to investigate the roles of LncRNA MIAT in neuronal inflammation and oxidative stress, MIAT shRNA (shMIAT) was transfected into MPP+-treated cells, and cell viability, cell apoptosis and oxidative stress response were evaluated. To evaluate the interactions between LncRNA MIAT and microRNA-221-3p (miR-221-3p)/TGF-β1/Nrf2, miR-221-3p mimic, miR-221-3p inhibitor, NC-inhibitor and transforming growth factor-β1 shRNA (shTGF-β1) were subsequently transfected into MPP+-treated cells. Dual-luciferase reporter gene assays were performed to determine the interaction of miR-221-3p with MIAT or TGFB receptor 1 (TGFBR1). The expressions of LncRNA MIAT, miR-221-3p, TGFBR1, transforming growth factor (TGF-β1) and nuclear factor E2-related factor 2 (Nrf2) were measured by quantitative reverse-transcription polymerase chain reaction (RT-qPCR) and immunoblotting. As a result, LncRNA MIAT was abundantly expressed in PD mice and cells, while downregulation of LncRNA MIAT promoted the survival of neurons, inhibited apoptosis and oxidative stress in neurons. LncRNA MIAT bound to miR-221-3p, and there was a negative correlation between miR-221-3p and LncRNA MIAT expression. In addition, miR-221-3p targeted TGFBR1 and suppressed TGF-β1 expression but increased Nrf2 expression. LncRNA MIAT promoted MPP+-induced neuronal injury in PD via regulating TGF-β1/Nrf2 axis through binding with miR-221-3p.

Knockdown of long noncoding RNA MIAT attenuates cigarette smoke-induced airway remodeling by downregulating miR-29c-3p–HIF3A axis

Chronic obstructive pulmonary disease (COPD) is a global public health issue and is defined as persistent airflow limitation. COPD is a major cause of morbidity and mortality worldwide. Long noncoding RNAs are involved in the course of pulmonary diseases. Here, we revealed that a long noncoding RNA called myocardial-infarction–associated transcript (MIAT) is upregulated in lung tissues of cigarette smoke (CS)-exposed mice. Knockdown of MIAT attenuated CS or CS-extract–induced inflammatory processes, epithelial-mesenchymal transition (EMT), and collagen deposition. Moreover, according to bioinformatic analyses and luciferase reporter assays, MIAT binds to microRNA-29c-3p (miR-29c-3p) and upregulates hypoxia-inducible factor 3 alpha (HIF3A), a target gene of miR-29c-3p. When the MIAT-specific short hairpin RNA and an miR-29c-3p inhibitor were cotransfected into cells, the inhibitor reversed the effects of MIAT knockdown on cell proliferation, apoptosis, inflammation, EMT, and collagen deposition. Overall, these results indicate that MIAT participates in CS-induced EMT and airway remodeling in COPD by upregulating miR-29c-3p–HIF3A axis output, thereby offering a novel promising biomarker for the assessment of COPD exacerbation induced by CS exposure.

LncRNA MIAT promotes hypoxia-induced H9C2 cell pyroptosis via binding to SF1 to inhibit CGRP transcription.

What is the central question of this study? How does long non-coding RNA myocardial infarction-associated transcript (lncRNA MIAT) function in hypoxia-induced H9C2 cells? What is the main finding and its importance? LncRNA MIAT inhibited transcription of calcitonin gene-related peptide by binding to splicing factor1, thereby promoting hypoxia-induced H9C2 cell pyroptosis. This study provides a new theoretical basis for the treatment of acute myocardial infarction by using lncRNA MIAT as a molecular target to mediate cardiomyocyte pyrodeath. Hypoxia induces severe cardiomyocyte pyroptosis, contributing to acute myocardial infarction. The aim of this study was to analyse the molecular mechanism of long non-coding RNA myocardial infarction-associated transcript (lncRNA MIAT) in hypoxia-induced H9C2 cell pyroptosis. A hypoxic H9C2 cell model was established. Cell viability was detected via the Cell Counting Kit-8 method. Levels of lactate dehydrogenase, malondialdehyde and superoxide dismutase and expressions of pyroptotic markers, lncRNA MIAT, splicing factor1 (SF1) and calcitonin gene-related peptide (CGRP) were detected via qRT-PCR. The subcellular localization of lncRNA MIAT was predicted and confirmed via LncATLAS and nuclear/cytosol fractionation assay. The binding relationships between lncRNA MIAT and SF1 and between SF1 and the CGRP promotor were verified via RNA immunoprecipitation. Rescue experiments were designed to confirm the role of lncRNA MIAT/SF1/CGRP in H9C2 cell pyroptosis. LncRNA MIAT was overexpressed in hypoxia-induced H9C2 cells. Hypoxia induced pyroptosis in H9C2 cells. Silencing of lncRNA MIAT enhanced cell viability and alleviated pyroptosis. LncRNA MIAT inhibited CGRP transcription via binding to SF1. Overexpression of SF1 promoted CGRP transcription and relieved H9C2 cell pyroptosis. Downregulation of CGRP reversed the role of silencing lncRNA MIAT in H9C2 cell pyroptosis. Overall, lncRNA MIAT inhibited CGRP transcription via binding to SF1, thereby promoting hypoxia-induced H9C2 cell pyroptosis.

Long Noncoding RNA MIAT Modulates the Extracellular Matrix Deposition in Leiomyomas by Sponging MiR-29 Family.

The objective of this study was to determine the expression and functional role of a long noncoding RNA (lncRNA) MIAT (myocardial infarction-associated transcript) in leiomyoma pathogenesis. Leiomyoma compared with myometrium (n = 66) expressed significantly more MIAT that was independent of race/ethnicity and menstrual cycle phase but dependent on MED12 (mediator complex subunit 12) mutation status. Leiomyomas bearing the MED12 mutation expressed higher levels of MIAT and lower levels of microRNA 29 family (miR-29a, -b, and -c) compared with MED12 wild-type leiomyomas. Using luciferase reporter activity and RNA immunoprecipitation analysis, MIAT was shown to sponge the miR-29 family. In a 3-dimensional spheroid culture system, transient transfection of MIAT siRNA in leiomyoma smooth muscle cell (LSMC) spheroids resulted in upregulation of miR-29 family and downregulation of miR-29 targets, collagen type I (COL1A1), collagen type III (COL3A1), and TGF-β3 (transforming growth factor β-3). Treatment of LSMC spheroids with TGF-β3 induced COL1A1, COL3A1, and MIAT levels, but repressed miR-29 family expression. Knockdown of MIAT in LSMC spheroids blocked the effects of TGF-β3 on the induction of COL1A1 and COL3A1 expression. Collectively, these results underscore the physiological significance of MIAT in extracellular matrix accumulation in leiomyoma.

Long non-coding RNA MIAT regulates ox-LDL-induced cell proliferation, migration and invasion by miR-641/STIM1 axis in human vascular smooth muscle cells

BackgroundAtherosclerosis (AS) is a primary cause of coronary heart and vascular diseases. Long non-coding RNAs (lncRNAs) are indicated to regulate AS progression. This study aimed to reveal the biological roles of lncRNA myocardial infarction associated transcript (MIAT) in oxidized low-density lipoprotein (ox-LDL)-induced human vascular smooth muscle cells (VSMCs).MethodsThe RNA levels of MIAT, microRNA-641 (miR-641) and stromal interaction molecule 1 (STIM1) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels were determined by western blot analysis. Cell proliferation was assessed by cell colony formation and DNA content quantitation assays. Cell migration and invasion were demonstrated by wound-healing and transwell assays. The putative binding relationships between miR-641 and MIAT or STIM1 were predicted by starbase online database, and identified by dual-luciferase reporter and RNA immunoprecipitation assays.ResultsMIAT and STIM1 expression were substantially upregulated, whereas miR-641 expression was downregulated in ox-LDL-induced VSMCs compared with control groups. Functionally, MIAT silencing attenuated ox-LDL-induced cell proliferation, migration and invasion in VSMCs; however, these effects were impaired by miR-641 inhibitor. STIM1 overexpression also restrained miR-641-mediated impacts on cell proliferation and metastasis under ox-LDL. Mechanistically, MIAT acted as a sponge for miR-641, and miR-641 was associated with STIM1.ConclusionsMIAT silencing hindered ox-LDL-induced cell proliferation, migration and invasion by downregulating STIM1 expression through binding to miR-641 in VSMCs. The mechanism provided us with a new target for AS therapy.

Silencing long non-coding RNA MIAT ameliorates myocardial dysfunction induced by myocardial infarction via MIAT/miR-10a-5p/EGR2 axis.

Long non-coding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) has been widely-demonstrated to function as diagnostic markers for acute myocardial infarction (MI). This study was designed to explore the modulatory role of MIAT and its underlying molecular mechanism in MI. Firstly, MI mouse model was developed via ligation of the descending branch of the left coronary artery, and cell model was established through exposure to hypoxic conditions. Online prediction indicated that MIAT could bind to microRNA-10a-5p (miR-10a-5p), while miR-10a-5p was highlighted to bind to early growth response gene-2 (EGR2). MIAT and EGR2 were subsequently determined to be highly-expressed, whereas miR-10a-5p was found to be poorly-expressed in cardiomyocytes exposed to hypoxia as well as in MI mice using RT-qPCR and Western blot assay. The binding relationships between MIAT and miR-10a-5p, and between miR-10a-5p and EGR2 were further confirmed by dual-luciferase reporter and RNA immunoprecipitation assays. The results of in vitro and in vivo experimentation also suggested that overexpression of miR-10a-5p or silencing of MIAT and EGR2 reduced cardiomyocyte apoptosis and increased ATP content, thus alleviating the impairment of cardiac function following MI. In a word, inhibition of MIAT protects against cardiac dysfunction induced by MI through the crosstalk with miR-10a-5p/EGR2.

Long Non-coding RNA MIAT Knockdown Prevents the Formation of Intracranial Aneurysm by Downregulating ENC1 via MYC.

Intracranial aneurysm (IA) is vascular enlargement occurred on the wall of cerebral vessels and can result in fatal subarachnoid hemorrhage when ruptured. Recent studies have supported the important role of long non-coding RNAs (lncRNAs) in IA treatment. This study identified functional significance of lncRNA myocardial infarction associated transcript (MIAT) in IA. Myocardial infarction associated transcript and ectodermal-neural cortex 1 (ENC1) expression was detected by reverse transcription quantitative polymerase chain reaction. Cell counting kit 8 assay flow cytometry were conducted to detect cell viability and apoptosis of endothelial cells in IA. The interaction among MIAT, ENC1, and myelocytomatosis oncogene (MYC) was analyzed by RNA pull down, RNA immunoprecipitation assay, chromatin immunoprecipitation assay, and dual luciferase reporter assay. Intracranial aneurysm was induced by ligating the left carotid artery and the bilateral posterior branch of the renal artery in rats for studying the role of MIAT and ENC1 in vivo. Myocardial infarction associated transcript and ENC1 were upregulated in IA. Endothelial cells in IA presented a decreased cell viability and an increased apoptotic rate. Myocardial infarction associated transcript could regulate the expression of ENC1, and MYC could bind to the promoter region of ENC1. High expression of MIAT increased endothelial cell apoptosis and vascular endothelial injury, while MIAT knockdown was identified to reduce the risk of IA both in vitro and in vivo through regulating ENC1. To sum up, MIAT silencing is preventive for IA occurrence by decreasing the MYC-mediated ENC1 expression, which represents a novel therapeutic target for IA.

Long Noncoding RNA MIAT Regulates the Process of Laryngeal Squamous Cell Carcinoma Through Regulation of miR-147a/BCOR

Myocardial infarction associated transcript (MIAT) is a long non-coding RNA (lncRNA) that can play oncogenic role in different kinds of cancers. However, its role in laryngeal squamous cell carcinoma (LSCC) remains unknown. The study aimed to explore the effect of MIAT/miR-147a/BCOR axis on LSCC progression. The expression pattern of MIAT, miR-147a and BCOR in LSCC samples and cells was identified through qRT-PCR. The proliferation of LSCC cells was assessed by colony formation assay and CCK-8 assays. Transwell assays were implemented to test the migratory and invasive abilities of LSCC cells. Proteins associated with migration and epithelial-mesenchymal transition were probed in transfected LSCC cells by western blot. The interaction of miR-147a with MIAT or BCOR was analyzed by luciferase reporter assays, RNA pulls down assays and Ago2-RIP assays. High MIAT expression was closely correlated with unfavorable prognosis. MIAT knockdown inhibited cell proliferation, migration, invasion and EMT progress in LSCC. MIAT acted as a miR-147a sponge to increase the expression of BCOR. Silencing of MIAT suppressed LSCC progression through miR-147a/BCOR axis. MIAT acts as an oncogene by controlling miR-147a/BCOR axis in LSCC.

Effects of long non-coding RNA myocardial infarction-associated transcript on retinal neovascularization in a newborn mouse model of oxygen-induced retinopathy.

Whether long non-coding RNA myocardial infarction-associated transcript is involved in oxygen-induced retinopathy remains poorly understood. To validate this hypothesis, we established a newborn mouse model of oxygen-induced retinopathy by feeding in an oxygen concentration of 75 ± 2% from postnatal day 8 to postnatal day 12, followed by in normal air. On postnatal day 11, the mice were injected with the myocardial infarction-associated transcript siRNA plasmid via the vitreous cavity to knockdown long non-coding RNA myocardial infarction-associated transcript. Myocardial infarction-associated transcript siRNA transcription significantly inhibited myocardial infarction-associated transcript mRNA expression, reduced the phosphatidylinosital-3-kinase, phosphorylated Akt and vascular endothelial growth factor immunopositivities, protein and mRNA expression, and alleviated the pathological damage to the retina of oxygen-induced retinopathy mouse models. These findings suggest that myocardial infarction-associated transcript is likely involved in the retinal neovascularization in retinopathy of prematurity and that inhibition of myocardial infarction-associated transcript can downregulate phosphatidylinosital-3-kinase, phosphorylated Akt and vascular endothelial growth factor expression levels and inhibit neovascularization. This study was approved by the Animal Ethics Committee of Shengjing Hospital of China Medical University, China (approval No. 2016PS074K) on February 25, 2016.

Long noncoding RNA MIAT regulates primary human retinal pericyte pyroptosis by modulating miR-342–3p targeting of CASP1 in diabetic retinopathy

Diabetic retinopathy (DR) is the leading cause of visual impairment and acquired blindness among adults worldwide. Retinal microvascular pericyte deficiency is one of the earliest pathological changes associated with DR, and long noncoding RNA myocardial infarction-associated transcript (MIAT) has been implicated as a crucial regulator of microvascular dysfunction in DR. Pyroptosis is a caspase-1-dependent proinflammatory form of cell death, and in the present study, we investigated the potential pyroptosis of primary human retinal pericytes (HRPCs) and the mechanism by which MIAT is involved in this process. We applied advanced glycation end product modified bovine serum albumin (AGE-BSA) to simulate the DR environment. The results suggested that AGE-BSA induced the active cleavage of caspase-1 and gasdermin D, the release of IL-1β, IL-18 and LDH, and reduced cell viability, which was prevented by the inhibition of caspase-1, indicating the occurrence of caspase-1-mediated pyroptosis in HRPCs. Immunofluorescence images revealed the phenotypic characteristics of pyroptosis, including pyknosis, swelling and hyperpermeability in plasmolemma. MIAT and CASP1 expression were substantially increased, while that of miR-342–3p was decreased in AGE-BSA-treated HRPCs. MIAT knockdown inhibited pyroptosis in HRPCs, which was reinforced by cotreatment with miR-342–3p mimic but relieved by cotreatment with miR-342–3p inhibitor. Furthermore, HRPC pyroptosis was inhibited by treatment with the miR-342–3p mimic alone but enhanced by the miR-342–3p inhibitor. Luciferase reporter assay results demonstrated binding between MIAT and miR-342–3p, as well as between miR-342–3p and CASP1. MIAT antagonized the effect of miR-342–3p on the depression of its target CASP1 and promoted AGE-BSA-induced pericyte pyroptosis. These findings may promote a better understanding of retinal pericyte depletion pathogenesis and the development of new therapeutic strategies for the treatment of diabetic retinopathy.