The long noncoding RNA Malat1: Its physiological and pathophysiological functions

Association of circulating long non-coding RNA MALAT1 in diagnosis, disease surveillance, and prognosis of acute ischemic stroke

We aimed to investigate the association of long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (lnc-MALAT1) with acute ischemic stroke (AIS), and its association with disease severity, inflammation, and recurrence-free survival (RFS) in AIS patients. One hundred and twenty AIS patients and 120 controls were recruited. Venous blood samples from AIS patients (within 24 h after symptoms onset) and controls (at entry to study) were collected to detect plasma lnc-MALAT1 expression by real-time quantitative polymerase chain reaction. AIS severity was assessed by the National Institutes of Health Stroke Scale (NIHSS) score. Plasma concentrations of inflammation factors (including C-reactive protein (CRP), tumor necrosis factor α (TNF-α), interleukin (IL)-6, IL-8, IL-10, IL-17, and IL-22) were measured and RFS was calculated. lnc-MALAT1 expression was decreased in AIS patients compared to controls, and it had a close correlation with AIS (AUC=0.791, 95% CI: 0.735-0.846). For disease condition, lnc-MALAT1 expression negatively correlated with NIHSS score and pro-inflammatory factor expression (including CRP, TNF-α, IL-6, IL-8, and IL-22), while it positively correlated with anti-inflammatory factor IL-10 expression. Furthermore, lnc-MALAT1 expression was elevated in AIS patients with diabetes. For prognosis, no statistical correlation of lnc-MALAT1 expression with RFS was found, while a trend for longer RFS was observed in patients with lnc-MALAT1 high expression compared to those with lnc-MALAT1 low expression.

The lncRNA MALAT1/miR-30/Spastin Axis Regulates Hippocampal Neurite Outgrowth

Spastin, a microtubule-severing enzyme, is important for neurite outgrowth. However, the mechanisms underlying the post-transcriptional regulation of spastin during microtubule-related processes are largely unknown. We demonstrated that the spastin expression level is controlled by a long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1)/microRNA-30 (miR-30) axis during neurite outgrowth. The miR-30 expression level decreased in hippocampal neurons with increasing days in culture, and miR-30 overexpression suppressed while miR-30 inhibition promoted neurite outgrowth in hippocampal neurons. Spastin was validated as a target gene of miR-30 using the luciferase reporter assay. The protein expression, microtubule severing activity, and neurite promoting effect of spastin were suppressed by the overexpression of miR-30 mimics and increased by miR-30 inhibitors. MALAT1 expression increased during neurite outgrowth and MALAT1 silencing impaired neurite outgrowth. miR-30 was a sponge target of MALAT1 and MALAT1/miR-30 altered neurite outgrowth in hippocampal neurons. MALAT1 overexpression reversed the inhibitory effect of miR-30 on the activity of a luciferase reporter construct containing spastin, as well as spastin mRNA and protein expression, indicating that spastin was a downstream effector of MALAT1/miR-30. The MALAT1/miR-30 cascade also modulated spastin-induced microtubule severing, and the MALAT1/miR-30/spastin axis regulated neurite outgrowth in hippocampal neurons. This study suggests a new mechanism governing neurite outgrowth in hippocampal neurons involving MALAT1/miR-30-regulated spastin expression.

The tRNA-like small noncoding RNA mascRNA promotes global protein translation

mascRNA is a small cytoplasmic RNA derived from the lncRNA MALAT1. After being processed by the tRNA processing enzymes RNase P and RNase Z, mascRNA undergoes CCA addition like tRNAs and folds into a tRNA-like cloverleaf structure. While MALAT1 functions in multiple cellular processes, the role of mascRNA was largely unknown. Here, we show that mascRNA binds directly to the multi-tRNA synthetase complex (MSC) component glutaminyl-tRNA synthetase (QARS). mascRNA promotes global protein translation and cell proliferation by positively regulating QARS protein levels. Our results uncover a role of mascRNA that is independent of MALAT1, but could be part of the molecular mechanism of MALAT1's function in cancer, and provide a paradigm for understanding tRNA-like structures in mammalian cells.

RNA processing in neurological tissue: development, aging and disease

Gene expression comprises a diverse array of enzymes, proteins, non-coding transcripts, and cellular structures to guide the transfer of genetic information to its various final products. In the brain, the coordination among genes, or lack thereof, characterizes individual brain regions, mediates a variety of brain-related disorders, and brings light to fundamental differences between species. RNA processing, occurring between transcription and translation, controls an essential portion of gene expression through splicing, editing, localization, stability, and interference. The machinery to regulate transcripts must operate with precision serving as a blueprint for proteins and non-coding RNAs to derive their identity. Therefore, RNA processing has a broad scope of influence in the brain, as it modulates cell morphogenesis during development and underlies mechanisms behind certain neurological diseases. Here, we present these ideas through recent findings on RNA processing in development and post-developmental maturity to advance therapeutic discoveries and the collective knowledge of the RNA life cycle.

Analytical ultracentrifuge: an ideal tool for characterization of non-coding RNAs

Analytical ultracentrifugation (AUC) has emerged as a robust and reliable technique for biomolecular characterization with extraordinary sensitivity. AUC is widely used to study purity, conformational changes, biomolecular interactions, and stoichiometry. Furthermore, AUC is used to determine the molecular weight of biomolecules such as proteins, carbohydrates, and DNA and RNA. Due to the multifaceted role(s) of non-coding RNAs from viruses, prokaryotes, and eukaryotes, research aimed at understanding the structure-function relationships of non-coding RNAs is rapidly increasing. However, due to their large size, flexibility, complicated secondary structures, and conformations, structural studies of non-coding RNAs are challenging. In this review, we are summarizing the application of AUC to evaluate the homogeneity, interactions, and conformational changes of non-coding RNAs from adenovirus as well as from Murray Valley, Powassan, and West Nile viruses. We also discuss the application of AUC to characterize eukaryotic long non-coding RNAs, Xist, and HOTAIR. These examples highlight the significant role AUC can play in facilitating the structural determination of non-coding RNAs and their complexes.

Long noncoding RNA HOTAIRM1 in human cancers

Long noncoding RNAs (lncRNAs) are a group of RNAs over 200 nucleotides in length involved in diverse processes in tumor cells including proliferation, invasion and apoptosis. Given these facts, it is hardly accidental that variations in the expression of some lncRNAs have been found to be closely related to carcinogenesis and tumor growth and metastasis. HOTAIRM1, first discovered as an important factor for granulocytic differentiation in NB4 promyelocytic leukemia, has been shown to be a salient cancer-related lncRNA abnormally expressed in a variety of tumors. In this review, we summarize current evidence on the critical role of HOTAIRM1 in human malignancy, its potential mechanism of action and future use in the development of effective therapeutics.

LncRNA MALAT1 mediates doxorubicin resistance of hepatocellular carcinoma by regulating miR-3129-5p/Nova1 axis

Drug resistance is one of the major challenges for cancer therapies. In recent years, research on disease-related molecular signaling pathways has become the key ways to understand and overcome obstacles. Dysregulation of MALAT1 could regulate doxorubicin resistance of hepatocellular carcinoma (HCC), but how MALAT1 involving in managing doxorubicin resistance remains unclear yet. We aimed to elucidate the specific molecular mechanism of MALAT1 with doxorubicin resistance in HCC cells. Quantitative real-time polymerase chain reaction (qRT-PCR) was engaged to detect the expression levels of MALAT1, miR-3129-5p and Nova1 mRNA; MTT, western blot, flow cytometry and luciferase reporter assays were executed to identify the influence of MALAT1 on doxorubicin resistance of HCC cells. Xenograft tumor model was created to confirm the biological function of MALAT1 in doxorubicin resistance of HCC cells in vivo. MALAT1 and Nova1 were upregulated, while miR-3129-5p expression was decreased in doxorubicin-resistant HCC tissues and cells. Knockdown of MALAT1 regulated doxorubicin resistance of HCC cells through inhibiting cell proliferation, migration, invasion and promoting apoptosis, but antisense miR-3129-5p released the functional effect of MALAT1 knockdown. Nova1, as a target gene of miR-3129-5p, reversed the results of miR-3129-5p expression and enhanced doxorubicin resistance of HCC cells. Xenograft tumor model suggested that dysregulation of MALAT1 regulated tumor growth and Nova1 to mediate doxorubicin resistance of HCC cells by as a sponge for miR-3129-5p in vivo. Elevation of LncRNA MALAT1 mediated doxorubicin resistance and the progression of HCC via a MALAT1/miR-3129-5p/Nova1 axis. This study would be expected to enrich the understanding of doxorubicin resistance of HCC and provide new ideas for HCC treatment strategies.

Neuro-protective roles of long non-coding RNA MALAT1 in Alzheimer's disease with the involvement of the microRNA-30b/CNR1 network and the following PI3K/AKT activation

Long non-coding RNAs (lncRNAs) have been increasingly found to fulfill key functions in neurodegenerative diseases. This study aimed to probe the function of lncRNA MALAT1 in neuronal recovery in Alzheimer's disease (AD). Aβ25-35 was used to induce AD in a rat model and neuronal injury in PC12 and C6 cells. Aberrantly expressed lncRNAs/microRNAs (miRNAs) in AD rats were screened out by microarray analyses. Altered expression of MALAT1, miR-30b and CNR1 was performed to explore their roles in neuronal recovery in rat and cell models. Consequently, LncRNA MALAT1 and CNR1 were poorly expressed while miR-30b was highly expressed in Aβ25-35-induced rat models and cells. Overexpression of MALAT1 or CNR1 reduced neuronal injury in rat hippocampus. It increased viability and decreased apoptosis in injured PC12 and C6 cells, and decreased the secretion of pro-inflammatory factor IL-6 and TNF-α but increased IL-10 production. However, overexpression of miR-30b reversed these trends. MALAT1 could served as a sponge for mR-30b to up-regulate CNR1 expression. The phosphorylation of PI3K and AKT was stimulated when MALAT1 or CNR1 was overexpressed. To sum up, we found MALAT1 could promote neuronal recovery following AD through the miR-30b/CNR1 network and the PI3K/AKT signaling activation.

Long noncoding RNA MALAT1 and its target microRNA-125b are potential biomarkers for Alzheimer's disease management via interactions with FOXQ1, PTGS2 and CDK5

This study aimed to investigate the intercorrelation among long noncoding RNA MALAT1 (lnc-MALAT1), microRNA-125b (miR-125b), FOXQ1, PTGS2 and CDK5, as well as their correlations with disease risk, severity and progression of Alzheimer's disease (AD). In total, 120 AD patients, 120 Parkinson's disease (PD) patients and 120 controls were enrolled. Cerebrospinal fluid (CSF) samples were collected from 50 AD patients, 50 PD patients and 50 controls; plasma samples were obtained from all participants. Lnc-MALAT1, miR-125b, FOXQ1, PTGS2 and CDK5 were detected by RT-qPCR. CSF lnc-MALAT1/FOXQ1 and plasma lnc-MALAT1 were downregulated, while CSF miR-125b/PTGS2/CDK5 and plasma miR-125b/PTGS2 were upregulated in AD patients compared to PD patients and controls, which differentiated AD patients from PD patients and controls, as demonstrated by ROC curve analyses. In AD patients, CSF/plasma lnc-MALAT1 negatively correlated with miR-125b and PTGS2 but positively correlated with FOXQ1; CSF/plasma miR-125b negatively correlated with FOXQ1 but positively correlated with PTGS2/CDK5. In addition, CSF/plasma lnc-MALAT1 and FOXQ1 correlated with alleviated disease severity, while miR-125b, PTGS2 and CDK5 correlated with exacerbated disease severity, which were manifested by their correlations with MMSE score, Aβ42, t-tau and p-tau in AD patients. However, their correlations with MMSE score, Aβ42, t-tau and p-tau were weak in PD patients and controls. Notably, CSF but not plasma lnc-MALAT1 and miR-125b could predict the MMSE score decline at 1 year, 2 years and 3 years in AD patients. In conclusion, lnc-MALAT1 and its target miR-125b are potential biomarkers for AD management via their intercorrelation with FOXQ1, PTGS2 and CDK5.

Environmental exposures and RNA N6-Methyladenosine modified long Non-Coding RNAs

Recent advances in the field of RNA modifications and long non-coding RNAs (lncRNAs) have provided substantial evidence on important biological functions. LncRNAs are defined as longer than 200 nucleotides which are not translated into proteins. The term "epitranscriptome" refers to all modifications in RNA types. Adenine-6 methylation (m⁶A) is the most common, dynamic and prominent modifications in coding and non-coding RNAs and has critical and previously unappreciated functional roles. Accumulation evidence indicated the association between RNA m6A modification and cancer and nonmalignant diseases. Recent studies reported that several lncRNAs including MALAT1, MEG3, XIST, GAS5, and KCNK15-AS1 are subject to m⁶A modification. It can be suggested that lncRNAs modified by m⁶A modification have substantive roles in diseases. Currently limited data are available regarding how environmental exposure affects m⁶A-modified lncRNAs. Furthermore, we do not know the interaction of environmental exposure and m⁶A-modified lncRNAs in development of adverse human health outcomes. Thus, in this systematic review, we aimed to present the data of the studies that reported a significant association between environmental exposure and expression/DNA methylation of m⁶A-modified long non-coding RNAs.

Non-coding RNAs, guardians of the p53 galaxy

The TP53 gene is arguably the most important tumor suppressor gene known, contributing multifaceted roles to the process of tumor development. Its protein product p53, is a crucial sequence-specific transcription factor which regulates the expression of a large network of protein-coding genes, as well as thousands of noncoding RNAs (ncRNAs), notably microRNAs and long ncRNAs (lncRNAs). Through a variety of direct and indirect mechanisms, ncRNAs in turn modulate p53 levels and activity. Here the numbers of studies are steadily building which link the contributions of dysregulated ncRNAs to tumorigenesis via their participation throughout the p53 regulatory network. In this review, we will examine how the principal forms of ncRNAs, namely microRNAs, lncRNAs and circular RNAs (circRNAs) function as either effectors or regulators amongst the diversity of p53's cellular responses. We first discuss the more recently discovered connections between miRNAs and p53 signaling before focusing on the remarkable diversity of crosstalk evident between lncRNAs and p53, and subsequently, developing reports linking circRNAs to p53. Highlighted throughout the review are the mechanistic impacts of dysregulated ncRNAs on p53 functions as well as the possible prognostic implications of these interactions. We also describe the emerging connections between ncRNAs and the often-perplexing functions of mutant p53. Finally, in the context of p53 therapeutic approaches, we describe some of the challenges in ncRNA research and their potential for translation.

LncRNA Malat1 inhibition of TDP43 cleavage suppresses IRF3-initiated antiviral innate immunity

Long noncoding RNAs (lncRNAs) involved in the regulation of antiviral innate immune responses need to be further identified. By functionally screening the lncRNAs in macrophages, here we identified lncRNA Malat1, abundant in the nucleus but significantly down-regulated after viral infection, as a negative regulator of antiviral type I IFN (IFN-I) production. Malat1 directly bound to the transactive response DNA-binding protein (TDP43) in the nucleus and prevented activation of TDP43 by blocking the activated caspase-3-mediated TDP43 cleavage to TDP35. The cleaved TDP35 increased the nuclear IRF3 protein level by binding and degrading Rbck1 pre-mRNA to prevent IRF3 proteasomal degradation upon viral infection, thus selectively promoting antiviral IFN-I production. Deficiency of Malat1 enhanced antiviral innate responses in vivo, accompanying the increased IFN-I production and reduced viral burden. Importantly, the reduced MALAT1, augmented IRF3, and increased IFNA mRNA were found in peripheral blood mononuclear cells (PBMCs) from systemic lupus erythematosus (SLE) patients. Therefore, the down-regulation of MALAT1 in virus-infected cells or in human cells from autoimmune diseases will increase host resistance against viral infection or lead to autoinflammatory interferonopathies via the increased type I IFN production. Our results demonstrate that the nuclear Malat1 suppresses antiviral innate responses by targeting TDP43 activation via RNA-RBP interactive network, adding insight to the molecular regulation of innate responses and autoimmune pathogenesis.

Regulation of a long noncoding RNA MALAT1 by aryl hydrocarbon receptor in pancreatic cancer cells and tissues

Environmental toxicants such as dioxins and polycyclic aromatic carbons are risk factors for pancreatitis and pancreatic cancer. These toxicants activate aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, of which activation regulates many downstream biological events, including xenobiotic metabolism, inflammation, and cancer cell growth and transformation. Here, we identified that environmental toxicant-activated AHR increased expression of metastasis associated lung adenocarcinoma transcript 1 (MALAT1) in pancreatic cancer cells and pancreatic tissues. The MALAT1 is a long noncoding (lnc) RNA which interacts with Enhancer of Zeste 2 (EZH2), a histone methyltransferase with epigenetic silencer activity, and the MALAT1-EZH2 interaction increased its epigenetic silencing activity. In contrast, AHR antagonist, CH223191 or resveratrol, counteracted the AHR-mediated MALAT1 induction and MALAT1-enahnced EZH2 activity. Collectively, these results revealed a novel pathway of how environmental exposure leads to epigenetic alteration via activation of AHR-MALAT1-EZH2 signaling axis under pancreatic tissue- and cancer cell-context.

Long Non-Coding RNA (lncRNA) Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1) Promotes Cell Proliferation and Migration by Regulating miR-143-3p and MAGE Family Member A9 (MAGEA9) in Oral Squamous Cell Carcinoma

Background

lncRNA MALAT1 is one of the most widely studied lncRNAs associated with various human cancers. The present study explored the functions and potential regulatory mechanisms of MALAT1 in oral squamous cell carcinoma (OSCC).

Material/Methods

We assessed levels of MALAT1, miR-143-3p, and MAGEA9 expression in OSCC tissues and cell lines by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assay. Proliferation and migration of CAL-27 cells were detected via CCK-8 and transwell assays, respectively. To study the relationships among MALAT1, miR-143-3p, and MAGEA9, we performed dual-luciferase assay and assessed the results using Spearman correlation analysis.

Results

QRT-PCR results showed that MALAT1 and MAGEA9 were expressed at higher levels and miR-143-3p was expressed at lower levels in OSCC tissues. Dramatic suppression of cell proliferation and migration abilities were caused by MALAT1 knockdown or miR-143-3p overexpression in CAL-27 cells. MALAT1 directly interacted with and negatively regulated miR-143-3p. Moreover, MAGEA9 was validated as a miR-143-3p target gene and was found to be negatively regulated by it. MALAT1 knockdown suppressed MAGEA9 protein expression and had the same effect as MAGEA9 knockdown. Additionally, MAGEA9 knockdown inhibited CAL-27 cell proliferation and migration abilities. Finally, in OSCC tissues, MALAT1 and miR-143-3p expression were negatively correlated and MALAT1 was positively correlated with MAGEA9 expression, while an inverse correlation between MAGEA9 and miR-143-3p expression was observed.

Conclusions

Taken together, our results suggest that MALAT1 functions as a competing endogenous RNA (ceRNA) in promoting OSCC cell proliferation and migration abilities through the miR-143-3p/MAGEA9 axis, thus providing new therapeutic targets for treatment of OSCC.

Role of Nrf2 in MALAT1/ HIF-1α loop on the regulation of angiogenesis in diabetic foot ulcer

Diabetic non healing wounds often result in significant morbidity and mortality. The number of effective targets to detect these wounds are meagre. Slow lymphangiogenesis is one of the complex processes involved in impaired healing of wounds. Long non coding RNAs (lncRNAs) have been importantly recognized for their role in pathological conditions. Multiple studies highlighting the role of lncRNAs in the regulation of several biological processes and complex diseases. Herein, we investigated the role of lncRNA Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the progression of diabetic foot ulcer (DFU). We report a significant reduction in the expression of lncRNA MALAT1 in the infected DFU subjects which was positively correlated with the expression of angiogenic factors such as Nrf2, HIF-1α and VEGF. Further, expression of pro-inflammatory markers TNF-α and IL-6 were found to be increased while, the expression of anti-inflammatory marker IL-10 was decreased in infected DFU tissues. Involvement of lncRNA MALAT1 in angiogenesis in EA.hy926 cells was demonstrated by silencing the expression of Nrf2, HIF-1α, and VEGF through interference mediated by MALAT1. In addition, its inflammatory role was demonstrated by decreased expression of TNF-α, IL-6 and not affecting the expression of IL-10. Further, CRISPR-Cas9 knock out of Nrf2 decreased the expression of lncRNA MALAT1, HIF-1α and VEGF which revealed the association of Nrf2 in regulating MALAT1/HIF-1α loop through positive feedback mechanism. Collectively, our results suggested the role of Nrf2 on MALAT1/HIF-1α loop in the regulation of angiogenesis, which could act as a novel target in the treatment of diabetic wounds.

Long non-coding RNA MALAT1 targeting STING transcription promotes bronchopulmonary dysplasia through regulation of CREB

Bronchopulmonary dysplasia (BPD) is a severe complication of preterm infants characterized by increased alveolarization and inflammation. Premature exposure to hyperoxia is believed to be a key contributor to the pathogenesis of BPD. No effective preventive or therapeutic agents have been created. Stimulator of interferon gene (STING) is associated with inflammation and apoptosis in various lung diseases. Long non-coding RNA MALAT1 has been reported to be involved in BPD. However, how MALAT1 regulates STING expression remains unknown. In this study, we assessed that STING and MALAT1 were up-regulated in the lung tissue from BPD neonates, hyperoxia-based rat models and lung epithelial cell lines. Then, using the flow cytometry and cell proliferation assay, we found that down-regulating of STING or MALAT1 inhibited the apoptosis and promoted the proliferation of hyperoxia-treated cells. Subsequently, qRT-PCR, Western blotting and dual-luciferase reporter assays showed that suppressing MALAT1 decreased the expression and promoter activity of STING. Moreover, transcription factor CREB showed its regulatory role in the transcription of STING via a chromatin immunoprecipitation. In conclusion, MALAT1 interacts with CREB to regulate STING transcription in BPD neonates. STING, CREB and MALAT1 may be promising therapeutic targets in the prevention and treatment of BPD.

Long non coding RNA NRON inhibited breast cancer development through regulating miR-302b/SRSF2 axis

AIMS

Long noncoding RNA NRON has been investigated in various tumors, such as hepatocellular carcinoma. However, the role of lncRNA NRON in breast cancer remains unclear. The aim of this study was to explore the function and mechanism of lncRNA NRON in breast cancer.

MATERIALS AND METHODS

Overexpression and knockdown vectors were constructed. Proliferation and invasion were measured to evaluate the function of lncRNA NRON. A dual-luciferase reporter assay was utilized to analyze the potential binding target of lncRNA NRON. A rescue experiment was performed to verify the relationship between lncRNA NRON and SRSF2.

RESULTS

Our results showed that the expression of lncRNA NRON was significantly downregulated in breast cancer tissues. Overexpression of lncRNA NRON significantly inhibited proliferation and invasion in breast cancer cell lines. Knockdown of lncRNA NRON promoted breast cancer development. We also provided evidence that lncRNA NRON negatively regulated miR-302b. Moreover, we identified SRSF2 as a downstream target of miR-302b.

CONCLUSION

Overall, we performed a comprehensive analysis to indicate that the lncRNA NRON/miR-302b/SRSF2 axis plays an important role in breast cancer. Our study is the first to prove that lncRNA NRON functions as a tumor suppressor in breast cancer.

TLR4 promotes microglial pyroptosis via lncRNA-F630028O10Rik by activating PI3K/AKT pathway after spinal cord injury

Neuroinflammation plays a crucial role in the secondary phase of spinal cord injury (SCI), and is initiated following the activation of toll-like receptor 4 (TLR4). However, the downstream mechanism remains unknown. Pyroptosis is a form of inflammatory programmed cell death, which is closely involved in neuroinflammation, and it can be regulated by TLR4 according to a recent research. In addition, several studies have shown that long non-coding RNAs (lncRNAs) based mechanisms were related to signal transduction downstream of TLR4 in the regulation of inflammation. Thus, in this study, we want to determine whether TLR4 can regulate pyroptosis after SCI via lncRNAs. Our results showed that TLR4 was activated following SCI and promoted the expression of lncRNA-F630028O10Rik. This lncRNA functioned as a ceRNA for miR-1231-5p/Col1a1 axis and enhanced microglial pyroptosis after SCI by activating the PI3K/AKT pathway. Furthermore, we determined STAT1 was the upstream transcriptional factor of IncRNA-F630028O10Rik and was induced by the damage-responsive TLR4/MyD88 signal. Our findings provide new insights and a novel therapeutic strategy for treating SCI.

Regulation of human Mcl-1 by a divergently-expressed antisense transcript

Mcl-1 is a member of the Bcl-2 anti-apoptotic protein family with important roles in the development, lifespan and metabolism of lymphocytes, as well as oncogenesis. Mcl-1 displays the shortest half-life of all Bcl-2 family members, with miRNA interference and proteasomal degradation being major pathways for Mcl-1 downregulation. In this study, we have identified a previously undescribed control mechanism active at the RNA level. A divergently transcribed lncRNA LOC107985203 (named here mcl1-AS1) negatively modulated Mcl-1 expression resulting in downregulation of Mcl-1 at both mRNA and protein level in a time-dependent manner. Using reporter assays, we confirmed that the mcl1-AS1 lncRNA promoter was located within Mcl-1 coding region. We next placed mcl1-AS1 under tetracycline-inducible control and demonstrated decreased viability in HEK293 cells upon doxycycline induction. Inhibition of mcl1-AS1 with shRNA reversed drug sensitivity. Bioinformatics surveys predicted direct mcl1-AS1 lncRNA binding to Mcl-1 transcripts, suggesting its mechanism in Mcl-1 expression is at the transcriptional level, consistent with a common role for anti-sense transcripts. The identification of a bi-directional promoter and lncRNA controlling Mcl-1 expression will have implications for controlling Mcl-1 activity in cancer cells, or for the purpose of enhancing the lifespan and quality of anti-cancer T lymphocytes.

Reduced serum and local LncRNA MALAT1 expressions are linked with disease severity in patients with non-traumatic osteonecrosis of the femoral head

OBJECTIVE

This study was performed to illustrate the potential relationship between reduced serum and local LncRNA MALAT1 expressions with disease severity in patients with non-traumatic osteonecrosis of the femoral head (ONFH).

METHODS

A total of 104 patients with non-traumatic ONFH and 100 healthy controls were consecutively recruited from our hospital. Serum and local LncRNA MALAT1 expressions were detected using real-time polymerase chain reaction (RT-PCR). Radiographic progression was defined by Ficat classification. Clinical severity was evaluated by Visual Analog Scale (VAS) and Harris Hip Score (HHS). Receiver operating characteristic (ROC) curve was carried out to determine the diagnostic value of MALAT1 in the radiographic progression.

RESULTS

Serum LncRNA MALAT1 expressions were significantly lower in non-traumatic ONFH patients than in healthy controls. In addition, local MALAT1 expressions in non-traumatic ONFH tissue were significantly lower in the affected area than in the non-affected area. Ficat grade 4 has significantly lower serum and local LncRNA MALAT1 expressions in comparison with grade 3, and Ficat grade 3 showed markedly decreased serum and local LncRNA MALAT1 expressions compared with grade 2. Serum and local LncRNA MALAT1 expressions were significantly and negatively associated with VAS and positively related to the HHS. Further ROC curve analysis indicated that serum MALAT1 may act as a decent indicator in the diagnosis of non-traumatic ONFH.

CONCLUSIONS

Decreased serum and local MALAT1 expressions may reflect disease severity in non-traumatic ONFH patients.

Nuclear export of chimeric mRNAs depends on an lncRNA-triggered autoregulatory loop in blood malignancies

Aberrant chromosomal translocations leading to tumorigenesis have been ascribed to the heterogeneously oncogenic functions. However, how fusion transcripts exporting remains to be declared. Here, we showed that the nuclear speckle-specific long noncoding RNA MALAT1 controls chimeric mRNA export processes and regulates myeloid progenitor cell differentiation in malignant hematopoiesis. We demonstrated that MALAT1 regulates chimeric mRNAs export in an m6A-dependent manner and thus controls hematopoietic cell differentiation. Specifically, reducing MALAT1 or m6A methyltransferases and the 'reader' YTHDC1 result in the universal retention of distinct oncogenic gene mRNAs in nucleus. Mechanically, MALAT1 hijacks both the chimeric mRNAs and fusion proteins in nuclear speckles during chromosomal translocations and mediates the colocalization of oncogenic fusion proteins with METTL14. MALAT1 and fusion protein complexes serve as a functional loading bridge for the interaction of chimeric mRNA and METTL14. This study demonstrated a universal mechanism of chimeric mRNA transport that involves lncRNA-fusion protein-m6A autoregulatory loop for controlling myeloid cell differentiation. Targeting the lncRNA-triggered autoregulatory loop to disrupt chimeric mRNA transport might represent a new common paradigm for treating blood malignancies.

CARMAL Is a Long Non-coding RNA Locus That Regulates MFGE8 Expression

Genome-wide association studies have identified several genetic loci linked to coronary artery disease (CAD) most of them located in non-protein coding regions of the genome. One such locus is the CAD Associated Region between MFGE8 and ABHD2 (CARMA), a ∼18 kb haplotype that was recently shown to regulate vicinal protein coding genes. Here, we further investigate the region by examining a long non-coding RNA gene locus (CARMAL/RP11-326A19.4/AC013565) abutting the CARMA region. Expression-genotype correlation analyses of public databases indicate that CARMAL levels are influenced by CAD associated variants suggesting that it might have cardioprotective functions. We found CARMAL to be stably expressed at relatively low levels and enriched in the cytosol. CARMAL function was investigated by several gene targeting approaches in HEK293T: inactive CRISPR fusion proteins, antisense, overexpression and inactivation by CRISPR-mediated knock-out. Modest increases in CARMAL (3–4×) obtained via CRISPRa using distinct single-guided RNAs did not result in consistent transcriptome effects. By contrast, CARMAL deletion or reduced CARMAL expression via CRISPRi increased MFGE8 levels, suggesting that CARMAL is contributing to reduce MFGE8 expression under basal conditions. While future investigations are required to clarify the mechanism(s) by which CARMAL acts on MFGE8, integrative bioinformatic analyses of the transcriptome of CARMAL deleted cells suggest that this locus may also be involved in leucine metabolism, splicing, transcriptional regulation and Shwachman-Bodian-Diamond syndrome protein function.

MALAT1 and BACH1 are prognostic biomarkers for triple-negative breast cancer

Aims

The purpose of this study was to investigate the potential correlation between metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and the transcription factor BTB and CNC homology 1 (BACH1) and their clinicopathological significance in triple-negative breast cancer (TNBC).

Subjects and Methods

MALAT1 and BACH1 were detected by immunohistochemistry using TNBC tissue microarrays of 240 patients. The association between MALAT1 and BACH1 expression levels was statistically analyzed. Moreover, the prognostic roles as well as clinical and pathological significance of MALAT1 and BACH1 expression in TNBC were determined.

Statistical Analysis Used

Two-tailed Pearson correlation was used to examine the correlation of BACH1 and MALA1 expression. Comparisons of clinicopathological variables between different BACH1 and MALA1 expression groups were performed using χ² tests. Overall survival (OS) and disease-free survival (DFS) curves were plotted with the Kaplan-Meier method and the differences in OS and DFS between three groups were compared by the log-rank test. Multiple comparisons were performed using χ² tests for subsequent individual group comparisons.

Results

MALAT1 and BACH1 expression was significantly correlated with tumor-node-metastasis stage, distant metastasis, pathological stage, and survival outcomes of patients. Patients with high MALAT1 and BACH1 expression exhibited shorter overall survival and disease-free survival.

Conclusions

These findings provide further insight into the expression pattern of MALAT1 and BACH1 in TNBC and suggest them as prognostic biomarkers for TNBC.

Long noncoding RNA MALAT1 regulates apoptosis in ischemic stroke by sponging miR-205-3p and modulating PTEN expression

Ischemic stroke has been considered to be one of the major causes of disability worldwide which related to multiple pathological processes including apoptosis. Metastasis associated lung adenocarcinoma transcript 1 (MALAT1), is one of the long non-coding RNA (lncRNA) know as a regulator for cell apoptosis. However, further and deeper cellular and molecular mechanism in stroke model remains unclear. The results showed MALAT1 was down-regulated in OGD-induced apoptosis and related with miR-205-3p expression. Knockdown of MALAT1 promote OGD-induced apoptosis, decreased the cell viability, inhibit the caspase-3 activation. Moreover, MALAT1 acts as a competing endogenous RNA (ceRNA) for miR-205-3p and further regulate PTEN expression protect OGD-induced apoptosis. Altogether, these results suggest that MALAT1 may suppress the apoptosis in ischemic stroke and function as a ceRNA for miR-205-3p to modulate PTEN expression. These findings may provide a novel therapeutic target for treating ischemic stroke.

MALAT1 Long Non-Coding RNA: Functional Implications

The mammalian genome is pervasively transcribed and the functional significance of many long non-coding RNA (lncRNA) transcripts are gradually being elucidated. Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is one of the most well-studied lncRNAs. MALAT1 is a highly conserved nuclear retained lncRNA that is abundantly expressed in cells and tissues and has been shown to play a role in regulating genes at both the transcriptional and post-transcriptional levels in a context-dependent manner. However, Malat1 has been shown to be dispensable for normal development and viability in mice. Interestingly, accumulating evidence suggests that MALAT1 plays an important role in numerous diseases including cancer. Here, we discuss the current state-of-knowledge in regard to MALAT1 with respect to its function, role in diseases, and the potential therapeutic opportunities for targeting MALAT1 using antisense oligonucleotides and small molecules.

Long noncoding RNA MSC-AS1 promotes hepatocellular carcinoma oncogenesis via inducing the expression of phosphoglycerate kinase 1

Background and Objectives

Increasing studies report that lncRNAs are dysregulated in hepatocellular carcinoma (HCC), which might function as significant diagnostic biomarkers of HCC. LncRNA MSC‐AS1 has been newly discovered in several cancers. However, its biological effect in HCC remains to be clearly elucidated. The aim of our work was to test MSC‐AS1 expression level and assess its function in HCC progression.

Methods

Expression levels of MSC‐AS1 and PGK1 in HCC were tested by qRT‐PCR in HCC cells including HUH‐7, BEL‐7404, SNU449, HepG2, QGY‐7701, and human normal liver cells (HL‐7702 cells). Association of MSC‐AS1 expression with various clinicopathological features and patients’ survival were analyzed by chi‐squared test and Kaplan‐Meier, respectively. The functions of MSC‐AS1 in HCC cells were investigated using EdU assay, colony formation, flow cytometry, would healing assay, and Transwell matrigel invasion assays. The correlation between MSC‐AS1 and PGK1 was confirmed using a RIP assay. Protein expression of PGK1 was evaluated using a western blot assay.

Results

MSC‐AS1 was obviously upregulated in HCC tissues and HCC cells. Knockdown of MSC‐AS1 repressed HepG2 and BEL‐7404 cell proliferation, colony formation capacity, and triggered cell apoptosis. HepG2 and BEL‐7404 cell cycle was blocked in G1 phase and cell migration/invasion was remarkably depressed. Downregulation of MSC‐AS1 in HCC cells reduced PGK1 expression. In vivo data demonstrated that silence of MSC‐AS1 suppressed HCC development via activating PGK1.

Conclusions

Taken these together, we indicated that MSC‐AS1 promoted HCC oncogenesis via inducing the expression of PGK1.

MALAT1 overexpression promotes the growth of colon cancer by repressing β-catenin degradation

Colon cancer is one of the most common types of cancer and more than 80% of colon cancer cases are associated with Wnt-β-catenin signaling activation. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a multi-functional long non-coding RNA that is overexpressed in many types of cancers, including colon cancer. In this study, MALAT1 and β-catenin were found to be overexpressed in tumor samples from 62 patients with colon cancer. A positive correlation was identified between MALAT1 levels and β-catenin protein levels in tumors. MALAT1 was found to upregulate β-catenin protein levels in HCT116 and LOVO cells without changing the mRNA expression levels. β-catenin degradation was confirmed to be upregulated in MALAT1-knockdown cells and inhibited in cells overexpressing MALAT1 overexpressing. MALAT1 was then identified as a negative regulator of GSK-3β; it did so via promotion of H3K27 trimethylation of the promoter region. In conclusion, MALAT1 is an oncogene in colon cancer, which inhibits β-catenin degradation by upregulating H3K27 trimethylation and repressing GSK-3β expression.

lncRNA MALAT1 modulates cancer stem cell properties of liver cancer cells by regulating YAP1 expression via miR‑375 sponging

Liver cancer stem cells (CSCs) are functionally defined by their ability to undergo self-renewal, and may contribute to metastasis, recurrence and drug resistance in liver cancer. The long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been implicated in tumor formation and metastasis of liver cancer. However, the exact mechanism by which MALAT1 modulates liver CSC features remains largely unknown. In the present study, the expression level of MALAT1 was elevated in cancer spheroids compared with the corresponding levels noted in parental liver cancer cells, whereas the suppression of MALAT1 resulted in markedly reduced sphere formation and decreased expression of stemness factors in liver cancer cells. Dual-luciferase assay and RNA pull-down assays further indicated an interaction between MALAT1 and microRNA (miR)-375, and identified Yes-associated protein 1 (YAP1) as a direct target of miR-375 in liver cancer cells. In addition, YAP1 expression was correlated with MALAT1 in liver cancer. The reduced expression of YAP1 caused by knockdown of MALAT1 with MALAT1 small interfering RNA (si-MALAT1) could be partially abolished by miR-375 inhibition, suggesting that MALAT1 may regulate YAP1 expression by sponging miR-375. Furthermore, YAP1 overexpression rescued the decrease in CSC features of liver cancer cells caused by si-MALAT1, further supporting that MALAT1-mediated YAP1 signaling was required for the stem-like characteristics of liver CSCs. The present study revealed that MALAT1 may promote CSC properties of liver cancer cells by upregulating YAP1 expression via sponging miR-375. The MALAT1/miR-375/YAP1 axis may serve as a novel target for liver cancer therapy, particularly for the eradication of liver CSCs.

Interaction between N6-methyladenosine (m6A) modification and noncoding RNAs in cancer

As a critical internal RNA modification in higher eukaryotes, N⁶-methyladenosine (m⁶A) has become the hotspot of epigenetics research in recent years. Extensive studies on messenger RNAs have revealed that m⁶A affects RNA fate and cell functions in various bioprocesses, such as RNA splicing, export, translation, and stability, some of which seem to be directly or indirectly regulated by noncoding RNAs. Intriguingly, abundant noncoding RNAs such as microRNAs, long noncoding RNAs, circular RNAs, small nuclear RNAs, and ribosomal RNAs are also highly modified with m⁶A and require m⁶A modification for their biogenesis and functions. Here, we discuss the interaction between m⁶A modification and noncoding RNAs by focusing on the functional relevance of m⁶A in cancer progression, metastasis, drug resistance, and immune response. Furthermore, the investigation of m⁶A regulatory proteins and its inhibitors provides new opportunities for early diagnosis and effective treatment of cancer, especially in combination with immunotherapy.

Single-cell RNA-seq analysis of the brainstem of mutant SOD1 mice reveals perturbed cell types and pathways of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which motor neurons throughout the brain and spinal cord progressively degenerate resulting in muscle atrophy, paralysis and death. Recent studies using animal models of ALS implicate multiple cell-types (e.g., astrocytes and microglia) in ALS pathogenesis in the spinal motor systems. To ascertain cellular vulnerability and cell-type specific mechanisms of ALS in the brainstem that orchestrates oral-motor functions, we conducted parallel single cell RNA sequencing (scRNA-seq) analysis using the high-throughput Drop-seq method. We isolated 1894 and 3199 cells from the brainstem of wildtype and mutant SOD1 symptomatic mice respectively, at postnatal day 100. We recovered major known cell types and neuronal subpopulations, such as interneurons and motor neurons, and trigeminal ganglion (TG) peripheral sensory neurons, as well as, previously uncharacterized interneuron subtypes. We found that the majority of the cell types displayed transcriptomic alterations in ALS mice. Differentially expressed genes (DEGs) of individual cell populations revealed cell-type specific alterations in numerous pathways, including previously known ALS pathways such as inflammation (in microglia), stress response (ependymal and an uncharacterized cell population), neurogenesis (astrocytes, oligodendrocytes, neurons), synapse organization and transmission (microglia, oligodendrocyte precursor cells, and neuronal subtypes), and mitochondrial function (uncharacterized cell populations). Other cell-type specific processes altered in SOD1 mutant brainstem include those from motor neurons (axon regeneration, voltage-gated sodium and potassium channels underlying excitability, potassium ion transport), trigeminal sensory neurons (detection of temperature stimulus involved in sensory perception), and cellular response to toxic substances (uncharacterized cell populations). DEGs consistently altered across cell types (e.g., Malat1), as well as cell-type specific DEGs, were identified. Importantly, DEGs from various cell types overlapped with known ALS genes from the literature and with top hits from an existing human ALS genome-wide association study (GWAS), implicating the potential cell types in which the ALS genes function with ALS pathogenesis. Our molecular investigation at single cell resolution provides comprehensive insights into the cell types, genes and pathways altered in the brainstem in a widely used ALS mouse model.

Long Non-Coding RNAs in Biliary Tract Cancer-An Up-to-Date Review

The term long non-coding RNA (lncRNA) describes non protein-coding transcripts with a length greater than 200 base pairs. The ongoing discovery, characterization and functional categorization of lncRNAs has led to a better understanding of the involvement of lncRNAs in diverse biological and pathological processes including cancer. Aberrant expression of specific lncRNA species was demonstrated in various cancer types and associated with unfavorable clinical characteristics. Recent studies suggest that lncRNAs are also involved in the development and progression of biliary tract cancer, a rare disease with high mortality and limited therapeutic options. In this review, we summarize current findings regarding the manifold roles of lncRNAs in biliary tract cancer and give an overview of the clinical and molecular consequences of aberrant lncRNA expression as well as of underlying regulatory functions of selected lncRNA species in the context of biliary tract cancer.

Long non-coding RNA MALAT1/microRNA 125a axis presents excellent value in discriminating sepsis patients and exhibits positive association with general disease severity, organ injury, inflammation level, and mortality in sepsis patients

Objective

The present study aimed to investigate the potential value of long non‐coding RNA metastasis‐associated lung adenocarcinoma transcript 1 (lnc‐MALAT1)/microRNA (miR)‐125a axis in disease management and prognosis surveillance of sepsis.

Methods

Totally, 196 sepsis patients and 196 healthy controls were enrolled. Blood samples were collected within 24 hours after admission in sepsis patients and were collected at enrollment in healthy controls. The relative expression of lnc‐MALAT1 and miR‐125a in all participants was detected by reverse transcription quantitative polymerase chain reaction, and the inflammatory cytokines in plasma of sepsis patients were measured by enzyme‐linked immunosorbent assay.

Results

Lnc‐MALAT1/miR‐125a axis was increased in sepsis patients compared with healthy controls (P < .001) and was of excellent value in distinguishing septic patients from healthy controls with the area under the curve (AUC) of 0.931 (95% CI: 0.908‐0.954). In sepsis patients, lnc‐MALAT1 was negatively associated with miR‐125a, and lnc‐MALAT1/miR‐125a axis was positively correlated with acute pathologic and chronic health evaluation II (APACHE II) score, Sequential Organ Failure Assessment (SOFA) score, serum creatinine, C‐reactive protein, tumor necrosis factor‐α, interleukin (IL)‐1β, IL‐6, and IL‐8, while negatively associated with albumin. Furthermore, lnc‐MALAT1/miR‐125a axis was of value in predicting increased 28‐day mortality risk to some extent (AUC: 0.678, 95% CI: 0.603‐0.754).

Conclusion

Lnc‐MALAT1/miR‐125a axis presents excellent value in differentiating sepsis patients from healthy controls and also exhibits positive association with general disease severity, organ injury, inflammation level, and mortality in sepsis patients.

Transcriptome Analyses of lncRNAs in A2E-Stressed Retinal Epithelial Cells Unveil Advanced Links between Metabolic Impairments Related to Oxidative Stress and Retinitis Pigmentosa

: Long non-coding RNAs (lncRNAs) are untranslated transcripts which regulate many biological processes. Changes in lncRNA expression pattern are well-known related to various human disorders, such as ocular diseases. Among them, retinitis pigmentosa, one of the most heterogeneous inherited disorder, is strictly related to oxidative stress. However, little is known about regulative aspects able to link oxidative stress to etiopathogenesis of retinitis. Thus, we realized a total RNA-Seq experiment, analyzing human retinal pigment epithelium cells treated by the oxidant agent N-retinylidene-N-retinylethanolamine (A2E), considering three independent experimental groups (untreated control cells, cells treated for 3 h and cells treated for 6 h). Differentially expressed lncRNAs were filtered out, explored with specific tools and databases, and finally subjected to pathway analysis. We detected 3,3'-overlapping ncRNAs, 107 antisense, 24 sense-intronic, four sense-overlapping and 227 lincRNAs very differentially expressed throughout all considered time points. Analyzed lncRNAs could be involved in several biochemical pathways related to compromised response to oxidative stress, carbohydrate and lipid metabolism impairment, melanin biosynthetic process alteration, deficiency in cellular response to amino acid starvation, unbalanced regulation of cofactor metabolic process, all leading to retinal cell death. The explored lncRNAs could play a relevant role in retinitis pigmentosa etiopathogenesis, and seem to be the ideal candidate for novel molecular markers and therapeutic strategies.

Long noncoding RNAs in osteosarcoma via various signaling pathways

Osteosarcoma is one of the most commonly seen bone malignancies with high incidence rate in both children and adults. Although the regulatory network of osteosarcoma has been greatly concerned for years, the mechanisms regarding its oncogenesis and development are still not clear. Recent discoveries have revealed that long noncoding RNAs (lncRNAs) play a crucial role in the development, progression, and invasion of osteosarcoma. Deregulated expression of lncRNAs has been found to participate in the regulation of various signaling transduction pathways in osteosarcoma. This review summarized roles of lncRNAs in the pathogenesis, development, and potential therapeutic of osteosarcoma via different signaling pathways. For examples, MALAT1, CCAT2, FER1L4, LOXL1‐AS1, OIP5‐AS1, PVT1, DBH‐AS1, and AWPPH regulate PI3K/Akt signaling; AWPPH and BE503655 regulate Wnt/β‐catenin signaling; NKILA and XIST regulate NF‐κB signaling; MEG3 and SNHG12 regulate Notch signaling; FOXD2‐AS1 and LINK‐A regulate HIF‐1α signaling; GClnc1 and HOTAIR regulate P53 signaling; ZFAS1, H19, and MALAT1 regulate MAPK, Hedgehog and Rac1/JNK signaling, respectively.

Nuclear hubs built on RNAs and clustered organization of the genome

RNAs play diverse roles in formation and function of subnuclear compartments, most of which are associated with active genes. NEAT1 and NEAT2/MALAT1 exemplify long non-coding RNAs (lncRNAs) known to function in nuclear bodies; however, we suggest that RNA biogenesis itself may underpin much nuclear compartmentalization. Recent studies show that active genes cluster with nuclear speckles on a genome-wide scale, significantly advancing earlier cytological evidence that speckles (aka SC-35 domains) are hubs of concentrated pre-mRNA metabolism. We propose the 'karyotype to hub' hypothesis to explain this organization: clustering of genes in the human karyotype may have evolved to facilitate the formation of efficient nuclear hubs, driven in part by the propensity of ribonucleoproteins (RNPs) to form large-scale condensates. The special capacity of highly repetitive RNAs to impact architecture is highlighted by recent findings that human satellite II RNA sequesters factors into abnormal nuclear bodies in disease, potentially co-opting a normal developmental mechanism.

Long Non-Coding RNA Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) Promotes Hypertension by Modulating the Hsa-miR-124-3p/Nuclear Receptor Subfamily 3, Group C, Member 2 (NR3C2) and Hsa-miR-135a-5p/NR3C2 Axis

Background

This study was designed to investigate the role of long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in the proliferation as well as apoptosis of human umbilical vein endothelial cells (HUVECs), to offer a basis for therapy of hypertension.

Material/Methods

The lncRNA MALAT1 expression, hsa-miR-124-3p, hsa-miR-135a-5p, hsa-miR-135b-5p, and hsa-miR-455-5p in plasma were measured from 230 patients with hypertension and 230 non-hypertensive controls. The mechanism for lncRNA MALAT1 modulating the proliferation and apoptosis of HUVECs was explored by cell transfection, Cell Counting Kit-8 (CCK-8), quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and dual-luciferase reporter assays.

Results

The expression of hsa-miR-124-3p and hsa-miR-135a-5p was reduced and the expression of lncRNA MALAT1 was increased in the plasma of hypertensive patients. Moreover, the plasma levels of hsa-miR-124-3p and hsa-miR-135a-5p of hypertensive patients were negatively correlated with lncRNA MALAT1 (r=−0.64, −0.72; P<0.01, P<0.01, respectively). The level of nuclear receptor subfamily 3, group C, member 2 (NR3C2) protein was negatively correlated with hsa-miR-124-3p and hsa-miR-135a-5p (r=−0.74, −0.84; P<0.01, P<0.01, respectively). The proliferation of HUVECs was inhibited after the inhibition of MALAT. Additionally, after knocking down MALAT, the levels of hsa-miR-124-3p and hsa-miR-135a-5p in HUVECs were markedly increased, while the expression level of NR3C2 protein was decreased. The apoptotic rate of HUVECs after the transfection of MALAT1 small interfering RNA (si-MALAT1) (3.64±0.21%) was significantly reduced compared to that of transfected si-MALAT1 no template control (NC) (3.76±0.19%) and the control group (10.51±1.24%).

Conclusions

LncRNA MALAT1 regulates proliferation and apoptosis of HUVECs through the hsa-miR-124-3p/NR3C2 and/or hsa-miR-135a-5p/NR3C2 axis.

The functions of N6-methyladenosine modification in lncRNAs

Increasing evidence indicates that mRNAs are often subject to posttranscriptional modifications. Among them, N6-methyladenosine (m6A), which has been shown to play key roles in RNA splicing, stability, nuclear export, and translation, is the most abundant modification of RNA. Extensive studies of m6A modification of mRNAs have been carried out, while little is known about m6A modification of long non-coding RNAs (lncRNAs). Recently, several studies reported m6A modification of lncRNAs. In this review, we focus on these m6A-modified lncRNAs and discuss possible functions of m6A modification.

Polysome-associated lncRNAs during cardiomyogenesis of hESCs

Long non-coding RNAs (lncRNAs) have been found to be involved in many biological processes, including the regulation of cell differentiation, but a complete characterization of lncRNA is still lacking. Additionally, there is evidence that lncRNAs interact with ribosomes, raising questions about their functions in cells. Here, we used a developmentally staged protocol to induce cardiogenic commitment of hESCs and then investigated the differential association of lncRNAs with polysomes. Our results identified lncRNAs in both the ribosome-free and polysome-bound fractions during cardiogenesis and showed a very well-defined temporal lncRNA association with polysomes. Clustering of lncRNAs was performed according to the gene expression patterns during the five timepoints analyzed. In addition, differential lncRNA recruitment to polysomes was observed when comparing the differentially expressed lncRNAs in the ribosome-free and polysome-bound fractions or when calculating the polysome-bound vs ribosome-free ratio. The association of lncRNAs with polysomes could represent an additional cytoplasmic role of lncRNAs, e.g., in translational regulation of mRNA expression.

Long non‑coding RNA MALAT1 promotes high glucose‑induced rat cartilage endplate cell apoptosis via the p38/MAPK signalling pathway

Diabetes mellitus (DM) contributes to intervertebral disc degeneration (IDD). The long non‑coding RNA MALAT1 has been revealed to play an important role in diabetes‑associated complications. However, the specific role of MALAT1 in diabetes‑associated IDD has not been determined. The aim of the present study was to evaluate the roles of MALAT1 in the apoptosis of cartilage endplate (CEP) cells induced by high glucose and to explore the mechanisms underlying this effect. Rat CEP cells were cultured in high‑glucose medium (25 mM glucose) for 24 or 72 h. Cells cultured in medium containing 5 mM glucose were used as a control. Flow cytometry was used to detect the degree of apoptosis. Reverse transcription‑quantitative PCR was used to measure the expression of MALAT1 mRNA. In addition, CEP cells were treated with different conditions (high glucose, high glucose + MALAT1 negative control, high glucose + MALAT1 RNAi, normal control) for 72 h. Flow cytometry was subsequently used to detect apoptosis and western blotting was used to measure the expression levels of total and phosphorylated p38. The results revealed that high glucose concentration promoted apoptosis and enhanced expression of MALAT1 in CEP cells. Furthermore, MALAT1 knockout decreased the expression levels of total and phosphorylated p38 and reduced the apoptosis of rat CEP cells. The results obtained in the present study indicated that MALAT1 may serve as an important therapeutic target for curing or delaying IDD in patients with diabetes.

Role of non-coding RNAs and RNA modifiers in cancer therapy resistance

As the standard treatments for cancer, chemotherapy and radiotherapy have been widely applied to clinical practice worldwide. However, the resistance to cancer therapies is a major challenge in clinics and scientific research, resulting in tumor recurrence and metastasis. The mechanisms of therapy resistance are complicated and result from multiple factors. Among them, non-coding RNAs (ncRNAs), along with their modifiers, have been investigated to play key roles in regulating tumor development and mediating therapy resistance within various cancers, such as hepatocellular carcinoma, breast cancer, lung cancer, gastric cancer, etc. In this review, we attempt to elucidate the mechanisms underlying ncRNA/modifier-modulated resistance to chemotherapy and radiotherapy, providing some therapeutic potential points for future cancer treatment.

An Update on Sepsis Biomarkers

Sepsis is a dysregulated systemic reaction to a common infection, that can cause life-threatening organ dysfunction. Over the last decade, the mortality rate of patients with sepsis has decreased as long as patients are treated according to the recommendations of the Surviving Sepsis Campaign, but is still unacceptably high. Patients at risk of sepsis should therefore be identified prior to the onset of organ dysfunction and this requires a rapid diagnosis and a prompt initiation of treatment. Unfortunately, there is no gold standard for the diagnosis of sepsis and traditional standard culture methods are time-consuming. Recently, in order to overcome these limitations, biomarkers which could help in predicting the diagnosis and prognosis of sepsis, as well as being useful for monitoring the response to treatments, have been identified. In addition, recent advances have led to the development of newly identified classes of biomarkers such as microRNAs, long-non-coding RNAs, and the human microbiome. This review focuses on the latest information on biomarkers that can be used to predict the diagnosis and prognosis of sepsis.

Quantitative Proteomics to Identify Nuclear RNA-Binding Proteins of Malat1

The long non-coding RNA Malat1 has been implicated in several human cancers, while the mechanism of action is not completely understood. As RNAs in cells function together with RNA-binding proteins (RBPs), the composition of their RBP complex can shed light on their functionality. We here performed quantitative interactomics of 14 non-overlapping fragments covering the full length of Malat1 to identify possible nuclear interacting proteins. Overall, we identified 35 candidates including 14 already known binders, which are able to interact with Malat1 in the nucleus. Furthermore, the use of fragments along the full-length RNA allowed us to reveal two hotspots for protein binding, one in the 5′-region and one in the 3′-region of Malat1. Our results provide confirmation on previous RNA-protein interaction studies and suggest new candidates for functional investigations.

Myeloid-derived suppressor cells-new and exciting players in lung cancer

Lung cancer (LC) is the leading cause of cancer-related death worldwide due to its late diagnosis and poor outcomes. As has been found for other types of tumors, there is increasing evidence that myeloid-derived suppressor cells (MDSCs) play important roles in the promotion and progression of LC. Here, we briefly introduce the definition of MDSCs and their immunosuppressive functions. We next specifically discuss the multiple roles of MDSCs in the lung tumor microenvironment, including those in tumor growth and progression mediated by inhibiting antitumor immunity, and the associations of MDSCs with a poor prognosis and increased resistance to chemotherapy and immunotherapy. Finally, we also discuss preclinical and clinical treatment strategies targeting MDSCs, which may have the potential to enhance the efficacy of immunotherapy.

Myeloid-derived suppressor cells-new and exciting players in lung cancer

Lung cancer (LC) is the leading cause of cancer-related death worldwide due to its late diagnosis and poor outcomes. As has been found for other types of tumors, there is increasing evidence that myeloid-derived suppressor cells (MDSCs) play important roles in the promotion and progression of LC. Here, we briefly introduce the definition of MDSCs and their immunosuppressive functions. We next specifically discuss the multiple roles of MDSCs in the lung tumor microenvironment, including those in tumor growth and progression mediated by inhibiting antitumor immunity, and the associations of MDSCs with a poor prognosis and increased resistance to chemotherapy and immunotherapy. Finally, we also discuss preclinical and clinical treatment strategies targeting MDSCs, which may have the potential to enhance the efficacy of immunotherapy.

Long noncoding RNA MALAT1 enhances the apoptosis of cardiomyocytes through autophagy modulation

Induction of autophagy promotes cardiomyocyte survival and confers a cardioprotective effect on acute myocardial infarction (AMI). Our previous study showed that knockdown of long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) attenuated myocardial apoptosis in mouse AMI. Herein, this study further investigated whether the mechanisms by which MALAT1 enhanced cardiomyocyte apoptosis involved the autophagy regulation. To address this, cardiomyocytes were isolated from neonatal mice and then stimulated with hypoxia/reoxygenation (H/R) injury to mimic AMI. The cell apoptosis was evaluated using TUNEL staining and Western blot analysis of apoptosis-related proteins. The autophagy level was assessed using GFP-LC3 immunofluorescence and Western blot analysis of autophagy-related proteins. The results showed that H/R injury increased MALAT1 expression. Furthermore, MALAT1 overexpression significantly enhanced apoptosis and regulated autophagy of cardiomyocytes, whereas MALAT1 knockdown exerted the opposite effect. Moreover, rapamycin (an autophagy activator) effectively attenuated the MALAT1-mediated enhancement of cardiomyocyte apoptosis. Overall, our findings demonstrated that the increased MALAT1 expression induced by H/R injury enhances cardiomyocyte apoptosis, at least in part, through autophagy modulation.

MALAT1 knockdown inhibits prostate cancer progression by regulating miR-140/BIRC6 axis

BACKGROUND

Prostate cancer (PCa) is the second most common cancer among men globally. Long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been reported to be implicated in tumorigenesis and progression of PCa. However, the pathogenesis of MALAT1 in PCa has not been thoroughly elaborated.

METHODS

RT-qPCR assay was conducted to measure expression of MALAT1, microRNA-140 (miR-140) and Baculoviral IAP repeat containing 6 (BIRC6) mRNA. Protein expression of BIRC6 was detected by western blot assay. Cell proliferative ability was assessed by MTS and Edu retention assays. Cell migratory and invasive abilities were evaluated by wound healing assay and Transwell invasion assay, respectively. Cell apoptotic rate was examined using a flow cytometry. The interaction between miR-140 and MALAT1 or BIRC6 3'UTR was explored by luciferase, RNA immunoprecipitation (RIP) and RNA pull down assays. Xenograft models of PCa were established to further explore the role and molecular mechanism of MALAT in PCa tumorigenesis in vivo.

RESULTS

MALAT1 and BIRC6 were highly expressed in human PCa tumor tissues and cell lines. MALAT1 or BIRC6 knockdown inhibited cell proliferation, migration and invasion and induced cell apoptosis in PCa. MiR-140 could directly bind with MALAT1 or BIRC6 3'UTR. Moreover, MALAT1 knockdown inhibited BIRC mRNA and protein expression through upregulating miR-140 in PCa cells. Additionally, MALAT1 knockdown inhibited PCa xenograft tumor growth by regulating miR-140/BIRC6 axis in vivo.

CONCLUSION

MALAT1 knockdown hindered PCa progression by regulating miR-140/BIRC6 axis in vitro and in vivo, hinting the potential value of MALAT1 in the management of PCa.