Role Of Myocardial Infarction Associated Transcript Research Articles

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.

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.

LncRNA MIAT can regulate the proliferation, apoptosis, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells by targeting miR-150-5p

ABSTRACT Osteoporosis (OP) is a systemic bone metabolic disease with complicated pathogenesis and is difficult to cure clinically. The regulatory mechanisms of OP are needed to be further investigated. In the present study, we focused on the role of myocardial infarction-associated transcript (MIAT) in OP development and examined the underlying mechanism. The serum expression levels of MIAT in samples from patients with OP and healthy controls were compared using quantitative reverse transcription-PCR (qRT-PCR). The dual-luciferase reporter assay was used to confirm the relationship between MIAT and its potential target microRNA, i.e., miR-150-5p. Moreover, bone marrow-derived mesenchymal stem cells (BMSCs) were cultured and transfected with MIAT shRNA, with or without miR-150-5p inhibitor. EdU staining and colony formation analysis were performed to determine the proliferation ability of these cells. Furthermore, the TUNEL assay and flow cytometry were used to assess BMSC apoptosis. Finally, RT-PCR and Western blot assays were employed to assess the expression of osteogenic differentiation biomarkers. Compared with controls, the expression of MIAT was significantly increased, whereas that of miR-150-5p was markedly decreased in patients with OP. MIAT and miR-150-5p expression levels exhibited a strong negative correlation. Furthermore, osteogenic differentiation indicators were suppressed in serum of OP patients. MIAT was downregulated, and miR-150-5p was upregulated in induced to osteogenic differentiation BMSCs. Furthermore, downregulation of MIAT dramatically promoted osteogenic differentiation, increased proliferation, and inhibited apoptosis in BMSCs; miR-150-5p inhibitor abrogated the effects of MIAT. In conclusion, lncRNA MIAT can regulate the proliferation, apoptosis, and osteogenic differentiation of BMSCs.

Long non-coding RNA MIAT promotes cervical cancer proliferation and migration.

Cervical cancer is one of the most common cancers in the world while its pathological mechanisms are not well-elucidated. Long non-coding RNA (lncRNA) has been implicated in cancer development. The dysregulation of lncRNA myocardial infarction-associated transcript (MIAT) has been reported in several cancers while its role in cervical cancer is not described yet. In this study, the role of MIAT in cervical cancer was explored. We evaluated the expression of MIAT in cervical cancer tissues and cell lines. Furthermore, we explored the effects of MIAT on proliferation and invasion of cervical cancer using cell model and animal transplantation model. We also evaluated the effects of MIAT on activation of PI3K/Akt/mTOR signalling pathway. Our results show that MIAT was up-regulated in cervical cancer tissues and cell lines. Knocking down MIAT resulted in decreased cell proliferation, migration and invasion of cervical cancer cells and suppression of tumour growth in mice. Mechanically, knocking down MIAT suppressed the activation of PI3K/Akt signalling pathway. In conclusion, MIAT promotes cell proliferation and invasion in cervical cancer.

Long noncoding RNA MIAT promotes the progression of acute myeloid leukemia by negatively regulating miR-495

Acute myeloid leukemia (AML) is a malignant myeloid hematopoietic stem and progenitor cell disease. Studies have shown that the long noncoding RNA (lncRNA) myocardial infarction associated transcript (MIAT) is abundantly expressed in multiple human solid tumors. However, the expression and role of MIAT in AML has not been explored previously. In this study, we find that MIAT is overexpressed in AML patient specimens and AML cell lines. Importantly, upregulation of MIAT is closely related with poor clinical outcome. Further investigations reveal that knockdown of MIAT inhibits the colony formation and proliferation, meanwhile, accelerates the apoptosis of AML cells in vitro. Consistently, MIAT knockdown slows AML progression in immunodeficient mice. Mechanistically, we confirm that MIAT can function as a sponge to inhibit microRNA-495 (miR-495), a tumor suppressor, in AML cells. Collectively, our results demonstrate that MIAT is involved in promoting the progression of AML, at least partly, through negative regulation of miR-495, and therefore provide a promising target for treatment of AML.

Silence of lncRNA MIAT protects ATDC5 cells against lipopolysaccharides challenge via up-regulating miR-132

The over-expanding role of lncRNA myocardial infarction associated transcript (MIAT) in various human diseases has been recently revealed. This study attempted to see the role of MIAT in a cell model of osteoarthritis (OA). ATDC5 cells were subjected to lipopolysaccharides (LPS) to mimic a cell model of OA. The effects of MIAT on the model were tested by performing CCK-8 assay, flow cytometry, qRT-PCR, western blot and ELISA. The downstream miRNA and signalling pathways were studied by utilizing qRT-PCR and western blot. Transfection of ATDC5 cells with the shRNA specific against MIAT significantly attenuated LPS-evoked apoptosis and cytokines release. At the meantime, the viability loss and the cleavage of caspases were ameliorated as well. MIAT overexpressed lead to the opposite result. Further, miR-132 was found to be negatively regulated by MIAT. The protective effects of MIAT silence were flattened when miR-132 expression was suppressed. Besides that the inhibitory effects of MIAT silence on LPS-evoked NF-κB and JNK activation were eliminated by miR-132 silence. This study illustrated that silence of MIAT protected ATDC5 cells against LPS challenge. The chondroprotective effects of MIAT silence may be via up-regulation of miR-132 and inhibition of NF-κB and JNK pathways.

The interaction of long non-coding RNA MIAT and miR-133 play a role in the proliferation and metastasis of pancreatic carcinoma

Pancreatic cancer (PC) is one of the most aggressive malignancies in humans. Despite advances in early detection and treatment of PC, the prognosis is still limited. LncRNA myocardial infarction–associated transcript (MIAT) is found abnormally expressed in a variety of cancers. However, the role of MIAT in PC is still unknown. This study aimed to explore whether MIAT was related to the progression of PC and the underlying mechanism. Bioinformatics analysis and luciferase reporter assay validated that miR-133 may target MIAT 3′-UTR. MIAT expression was found remarkably increased and miR-133 expression was significantly decreased in PC tissues and PC cell lines (PATU-8988, BxPC-3, PANC-1, SW1990 and AsPC-1 cells). PC patients with high MIAT level had poor prognosis than that with low MITA level. Besides that, PATU-8988 cells transfected with siMIAT and/or miR-133 inhibitor. The results exhibited that the inhibition of miR-133 expression reversed the inhibition effect of MIAT down-regulation in the growth, migration and invasion of PC cells. Moreover, tumor growth was tremendously suppressed in nude rats received injection of PATU-8988 cells transfected with siMIAT. Taken together, our results suggest that the interaction of MIAT and miR-133 play a role in the proliferation and metastasis of pancreatic carcinoma.

Silencing of Long Non-coding RNA MIAT Sensitizes Lung Cancer Cells to Gefitinib by Epigenetically Regulating miR-34a.

Long non-coding RNA (lncRNA) myocardial infarction associated transcript (MIAT) was recently identified as oncogene in several cancers. However, the role of MIAT on acquired resistance in lung cancer and the underlying mechanisms remain unclear. Here, we showed that the expression of MIAT in lung cancer tissues was upregulated compared with adjacent tissues. LncRNA MIAT expression was associated with tumor size, lymph node metastasis, distant metastasis and TNM stage. Univariate analysis and multivariate analysis revealed that the lncRNA MIAT to be an independent factor for predicating the prognosis of lung cancer patients. Low lncRNA MIAT have longer overall survival time and progression-free survival time than patients with high lncRNA MIAT expression. Moreover, the knockdown of MIAT significantly sensitized PC9 and gefitinib-resistant PC9 cells to gefitinib in vitro and in vivo, and increased the expression of miR-34a and inactivated PI3K/Akt signaling. MIAT interacted with miR-34a and epigenetically controlled the miR-34a expression by hyper-methylating its promotor. Taken together, our findings demonstrated that knockdown of MIAT by siRNA enhances lung cancer cells to gefitinib through the PI3K/Akt signaling pathway by epigenetically regulating miR-34a. Thus, MIAT may be a useful prognostic marker and therapeutic target for lung cancer patients.

Abstract 217: Long Non-coding RNA Myocardial Infarction-associated Transcript (MIAT) Protects Cardiac Progenitor Cells From Oxidative Stress-induced Cell Death

Background: Long non-coding RNAs (lncRNAs) are an emerging class of RNAs with no or limited protein-coding capacity; a few of which have recently been shown to regulate critical biological processes. Myocardial infarction-associated transcript (MIAT) is a conserved mammalian lncRNA, and single nucleotide polymorphisms (SNPs) in 6 loci of this gene have been identified to be strongly associated with the incidence and severity of human myocardial infarction (MI). However, whether and how MIAT impacts on the pathogenesis of MI is unknown. Methods & Results: Quantitative RT-PCR analyses revealed that MIAT is expressed in neonatal mouse heart and to a lesser extent in adult heart. After surgical induction of MI in adult mice, MIAT starts to increase in 2 hours, peaks at 6 hours in atria and 12 hours in ventricles, and decreases to baseline at 24 hours. Fluorescent in situ hybridization (FISH) revealed a slight increase in the number of MIAT-expressing cells in the infarct border zone at 12 hours post-MI. Moreover, qRT-PCR analyses of isolated cardiac cells revealed that MIAT is predominantly expressed in cardiosphere-derived cardiac progenitor cells (CPCs). Treatment of CPCs with H 2 O 2 led to a marked upregulation of MIAT, while knockdown (KD) of MIAT resulted in a significantly impaired cell survival in vitro with H 2 O 2 treatment and in vivo after administered in the ischemic/reperfused heart. Notably, bioinformatics prediction and RNA immunoprecipitation identified FUS (fused in sarcoma) as a novel MIAT-interacting protein. FUS-KD CPCs displayed reduced cell viability and increased apoptosis under oxidative stress. Furthermore, MIAT overexpression enhanced survival of WT CPCs but not FUS-KD CPCs, suggesting that the protective role of MIAT is mediated by FUS. Conclusions: MIAT interacts with FUS to protect CPCs from oxidative stress-induced cell death.