MALAT1 Knockdown Research Articles

Competing endogenous RNA network associated with oxygen-induced retinopathy: Expression of the network and identification of the MALAT1/miR-124–3p/EGR1 regulatory axis

Retinopathy of prematurity (ROP) is a severe retinal dysfunction in prematurely born babies. The relationship between non-coding RNAs and retinopathy of prematurity (ROP) remain unclear. Microarray analysis of lncRNAs, miRNAs, and mRNAs was conducted in a mouse model of ROP. A competing endogenous RNA (ceRNA) network was constructed. The relationship among MALAT1, miR-124–3p, and Early growth response protein 1 (EGR1) was assessed in hypoxia-induced primary human umbilical vein endothelial cells (HUVECs) and ROP mouse model. In the study, we found 2252 lncRNAs, 1239 mRNAs, and 36 miRNAs were differentially regulated. ceRNA network consisting of 21 lncRNAs, 10 miRNAs, and 19 mRNAs was established. Of the most down-regulated miRNAs, miR-124–3p was selected for additional study. miR-124–3p ceased the migration and proliferation of primary HUVECs in hypoxic conditions, and directly suppressed EGR1. Additionally, MALAT1 directly sponged miR-124–3p. Knockdown of MALAT1 decreased EGR1 expression and inhibited the migration and proliferation of primary HUVECs in hypoxia. Furthermore, these changes were rescued by depletion of miR-124–3p. In vivo, intravitreal injection of miR-124–3p, shMALAT1 decreased EGR1 expression and markedly suppressed retinal neovascularization in OIR models. Intravitreal injection of shMALAT1 and miR-124–3p antagomir at the same time can promote retinal neovascularization, which reversed the suppression of retinal neovascularization functioned by shMALAT1. In conclusion, the expression profiles of lncRNAs and miRNAs and the ceRNA network in a mouse model of ROP may be indicative of the underlying mechanisms of retinal angiogenesis and neural activity. The MALAT1/miR-124–3p/EGR1 regulatory axis is partly responsible for retinal neovascularization, which may provide a novel theoretical basis for the pathogenesis of ROP.

PFOI stimulates the motility of T24 bladder cancer cells: Possible involvement and activation of lncRNA malat1

Perfluorinated iodine alkanes (PFIs) can serve as an important raw materials for the synthesis of various perfluorinated chemical products through telomerization reaction. The estrogenic effects of PFIs have been reported previously by some in vitro and in vivo screening assays. To explore the potential epigenetic toxicity of PFIs, activation of lncRNAs was screened, and the cell motility changes induced by perfluorooctyl iodide (PFOI) were analyzed in this study. High metastatic bladder cell line (T24) was used to investigate the cellular migration function affected by PFOI. PFOI exposure significantly induced the upregulation of lncRNA anril, thorlnc, hotairm1, meg3, and malat1. The migration and invasion of T24 cells were also enhanced upon PFOI exposure. The transcription level of matrix metalloenzyme genes, epidermal growth factors, cytoskeleton genes, and the upstream factors involved in cell motility pathways were examined to illustrate possible mechanisms. Additionally, the basic role of malat1 in cellular motility was investigated by lncRNA knockdown and migration assays. The knockdown of malat1 inhibited the cellular motility induced by PFOI. The levels of MMP-2/-9 genes were also down-regulated by the treatment of si-malat1. Overall, the perturbation of cytoskeleton genes (E-cadherin/N-cadherin) may account for the impact on the motility of T24 cells. Our studies indicate that perfluorinated chemicals might regulate the lncRNAs, thus promoting the metastasis of the tumor cells.

Knockdown of lncRNA MALAT1 ameliorates acute kidney injury by mediating the miR-204/APOL1 pathway.

BackgroundAcute kidney injury (AKI) was characterized by loss of renal function, associated with chronic kidney disease, end‐stage renal disease, and length of hospital stay. Long non‐coding RNAs (lncRNAs) participated in AKI development and progression. Here, we aimed to investigate the roles and mechanisms of lncRNA MALAT1 in AKI.MethodsAKI serum samples were obtained from 129 AKI patients. ROC analysis was conducted to confirm the diagnostic value of MALAT1 in differentiating AKI from healthy volunteers. After hypoxic treatment on HK‐2 cells, the expressions of inflammatory cytokines, MALAT1, miR‐204, APOL1, p65, and p‐p65, were measured by RT‐qPCR and Western blot assays. The targeted relationship between miR‐204 and MALAT1 or miR‐204 and APOL1 was determined by luciferase reporter assay and RNA pull‐down analysis. After transfection, CCK‐8, flow cytometry, and TUNEL staining assays were performed to evaluate the effects of MALAT1 and miR‐204 on AKI progression.ResultsFrom the results, lncRNA MALAT1 was strongly elevated in serum samples from AKI patients, with the high sensitivity and specificity concerning differentiating AKI patients from healthy controls. In vitro, we established the AKI cell model after hypoxic treatment. After experiencing hypoxia, we found significantly increased MALAT1, IL‐1β, IL‐6, and TNF‐α expressions along with decreased miR‐204 level. Moreover, the targeted relationship between MALAT1 and miR‐204 was confirmed. Silencing of MALAT1 could reverse hypoxia‐triggered promotion of HK‐2 cell apoptosis. Meanwhile, the increase of IL‐1β, IL‐6, and TNF‐α after hypoxia treatment could be repressed by MALAT1 knockdown as well. After co‐transfection with MALAT1 silencing and miR‐204 inhibition, we found that miR‐204 could counteract the effects of MALAT1 on HK‐2 cell progression and inflammation after under hypoxic conditions. Finally, NF‐κB signaling was inactivated while APOL1 expression was increased in HK‐2 cells after hypoxia treatment, and lncRNA MALAT1 inhibition reactivated NF‐κB signaling while suppressed APOL1 expression by sponging miR‐204.ConclusionsCollectively, these results illustrated that knockdown of lncRNA MALAT1 could ameliorate AKI progression and inflammation by targeting miR‐204 through APOL1/NF‐κB signaling.

LNA -Gapmer Antisense Oligonucleotides Targeting the Oncogenic Lncrna MALAT1 Trigger Anti-Multiple Myeloma Activity By Proteasome Blockade

Dysregulation of non-coding RNAs is emerging as a common feature of human cancer. While short non-coding RNAs have been extensively investigated in multiple myeloma (MM), the biological role and the therapeutic significance of aberrantly expressed long non-coding RNAs (lncRNAs) are yet undetermined. A proprietary custom annotation pipeline of microarray data on lncRNA expression in different plasma cell (PC) dyscrasias, including 20 MGUS, 33 smoldering MM, 170 MM, 36 PC leukemia patients and 9 healthy donors, revealed high expression of MALAT1 in MM PCs. On this finding, we investigated the functional significance of MALAT1 by using novel 16-mer LNA gapmeR synthetic ASOs, that trigger selective RNAse-H dependent degradation of MALAT1. LNA-gapmeR ASOs targeting MALAT1 inhibited proliferation and clonogenicity of MM cell lines (n=7) and patient PCs (n=5), triggering ER-stress response and apoptosis, even in the presence of bone marrow stromal cells, while sparing healthy peripheral blood mononuclear cells. Conversely, MALAT1-enforced expression by lentiviral vectors enhanced cell proliferation and migration, reverted the effect of anti-MALAT1 ASOs and activated major oncogenic signal transduction pathways, such as AKT and MAPK. In vivo, i.p. administration of anti-MALAT1 gapmeRs inhibited the growth of human MM xenografts, with no evidence of organ toxicity. Microarray gene expression profiling indicated that MALAT1 depletion downregulated genes encoding for 20S proteasome β-subunits, as evidenced by gene set enrichment analysis (GSEA).Down-modulation of PSMβ2/4/5/7 mRNA and protein by anti-MALAT1 ASOs was confirmed by qPCR and Western blot respectively, and was associated to reduced trypsine-, chymotrypsine- and caspase-like proteasome activities and to the accumulation of polyubiquitylated proteins. Mechanistically, we demonstrated that proteasome inhibition upon MALAT1 knock-down was due to downmodulation of the major transcriptional activators of proteasome gene expression NRF1 and NRF2. At the same time, NRF1 was found to bind to and transactivate MALAT1 promoter, as demonstrated by chromatin immunoprecipitation and reporter assays, thus establishing a positive feedback-loop with MALAT1. Intriguingly, this loop was overactivated in bortezomib-resistant MM cells. Collectively, our findings highlight an unprecedented role of the lncRNA MALAT1 in the regulation of the proteasome machinery, and provide the first preclinical rationale for using ASO therapeutics targeting dysregulated lncRNAs for MM treatment. DisclosuresNo relevant conflicts of interest to declare.

LncRNA MALAT1 Accelerates Cervical Carcinoma Proliferation by Suppressing miR-124 Expression in Cervical Tumor Cells.

Emerging studies have clarified the critical role of LncRNA MALAT1 in various pathological progressions. Here, we identified its positive relationship with cervical carcinoma proliferation. Cervical carcinoma has been considered as one of the most malignant tumors among female. Thus, our study was designed to investigate the underlying mechanism of LncRNA MALAT1 on cervical tumor cell proliferation. We observed that miR-124 was the potential target of LncRNA MALAT1 in cervical tumor cell lines (Hela, C-33A, Caski, and SiHa), the expression level of which is negatively correlated with LncRNA MALAT1 in cervical tumor cells, tissues of cervical patients, and mice. Gain- or loss-of-function analyses in cervical tumor cells have further verified the regulatory role of MALAT1 on miR-124. Additionally, the proliferation of cervical carcinoma was inhibited by miR-124 overexpression, whereas it was blocked by LV-MALAT1 transfection. In vivo assays, overexpression of miR-124, or knockdown of MALAT1 exhibited beneficial effects on tumor weight, size, and volume, together with elevating the survival rate, tightly related with the progression of cervical cancer. In conclusion, LncRNA MALAT1 disabled the effects of miR-124 as an inhibitory sponge, accelerating the progression of cervical carcinoma.

The role of biomechanical forces and MALAT1/miR-329-5p/PRIP signalling on glucocorticoid-induced osteonecrosis of the femoral head.

Glucocorticoid‐induced osteonecrosis of the femoral head (GIONFH) is a common orthopaedic disease. GIONFH primarily manifests clinically as hip pain in the early stages, followed by the collapse of the femoral head, narrowing of the hip joint space and damage to the acetabulum, resulting in severely impaired mobility. However, the pathogenesis of GIONFH is not clearly understood. Recently, biomechanical forces and non‐coding RNAs have been suggested to play important roles in the pathogenesis of GIONFH. This study aimed to evaluate the role of biomechanical forced and non‐coding RNAs in GIONFH. We utilized an in vivo, rat model of GIONFH and used MRI, μCT, GIONFH‐TST (tail suspension test), GIONFH‐treadmill, haematoxylin and eosin staining, qRT‐PCR and Western blot analysis to analyse the roles of biomechanical forces and non‐coding RNAs in GIONFH. We used RAW264.7 cells and MC3T3E1 cells to verify the role of MALAT1/miR‐329‐5p/PRIP signalling using a dual luciferase reporter assay, qRT‐PCR and Western blot analysis. The results demonstrated that MALAT1 and PRIP were up‐regulated in the femoral head tissues of GIONFH rats, RAW264.7 cells, and MC3T3E1 cells exposed to dexamethasone (Dex). Knockdown of MALAT1 decreased PRIP expression in rats and cultured cells and rescued glucocorticoid‐induced osteonecrosis of femoral head in rats. The dual luciferase reporter gene assay revealed a targeting relationship for MALAT1/miR‐329‐5p and miR‐329‐5p/PRIP in MC3T3E1 and RAW264.7 cells. In conclusion, MALAT1 played a vital role in the pathogenesis of GIONFH by binding to (‘sponging’) miR‐329‐5p to up‐regulate PRIP. Also, biomechanical forces aggravated the pathogenesis of GIONFH through MALAT1/miR‐329‐5p/PRIP signalling.

Knockdown of Malat1 alleviates high-glucose-induced angiogenesis through regulating miR-205-5p/VEGF-A axis

Diabetic retinopathy (DR), characterized by intraretinal vessel formation, is a major complication in diabetes. Neovascularization is an important characteristic of DR, but its formation mechanism remains unclear. In this research, Malat1, miR-205-5p, and VEGF-A levels in high glucose (HG) treat-human retinal microvascular endothelial cells (hRMECs) was detected with qRT-PCR. CCK-8 assay, transwell assay, and tube formation assay was applied to access hRMEC viability, migration, and angiogenesis. Expression level of endothelial-mesenchymal transition (EndMT) markers (VE-cadherin, FSP1, and α-SMA) was detected by western blotting assay. Interaction among Malat1, miR-205-5p, and VEGF-A was confirmed by dual-luciferase reporter assay. Furthermore, in vivo DR mouse model was induced, and the effect of Malat1 on DR and EndMT markers was confirmed through hematoxylin-eosin (HE) staining and western blotting. As a result, Malat1 and VEGF-A was upregulated while miR-205-5p was suppressed under HG conditions. Malat1 could sponge miR-205-5p to regulate VEGF-A expression. Malat1 knockdown inhibited hRMEC proliferation, migration, and tube formation by targeting miR-205-5p under HG conditions. Furthermore, inhibition of Malat1 prevented the HG-induced EndMT process. In summary, Malat1 knockdown diminished hRMEC dysfunctions by regulating miR-205-5p/VEGF-A, providing a useful insight for exploring new therapeutic target for DR.

MALAT1 knockdown protects from bronchial/tracheal smooth muscle cell injury via regulation of microRNA-133a/ryanodine receptor 2 axis

Asthma has significant impacts on living quality particularly in children. Long noncoding RNA (lncRNA) MALAT1 plays a crucial role in neonatal respiratory diseases. Meanwhile, MALAT1 knockdown could induce viability and attenuate apoptosis of airway-related cells. However, the role of MALAT1 in neonatal asthma, asthma-related cell, and its possible mechanism is unclear. This study aims to investigate MALAT1 level in asthma and to identify the effects of MALAT1 on bronchial/tracheal smooth muscle cells (B/TSMCs). Newborn asthma modeling rat was constructed by introducing ovalbumin (OVA). MALAT1 levels in tissues or B/TSMCs were determined by RT-qPCR. Exogenous changes of MALAT1, RyR2 or miR-133a in B/TSMCs were fulfilled by cell transfection; cell apoptosis was measured by using Cell Death Detection ELISA kit and Hochest33342; IL-6, TNF-α and IL-1β level was detected by using corresponding ELISA kit; ryanodine receptor 2 (RyR2) mRNA and miR-133a level was determined by RT-qPCR; cleaved caspase-3 (c-caspase-3) and RyR2 expression was detected by Western blot; luciferase reporter assay was performed to confirm the target regulation of miR-133a on RyR2. We found that MALAT1 was significantly upregulated in tracheal tissues of newborn asthma modeling rats. In MALAT1-silenced or -overexpressed B/TSMCs, we found a synchronous change of cell apoptosis, inflammatory factor secretion (IL-6, TNF-α, and IL-1β) or RyR2 level, but a reverse change of miR-133a level with MALAT1. Besides, MALAT1 induced B/TSMCs apoptosis and inflammation increase could be partially reversed when RyR2 was silenced or when miR-133a was overexpressed. The luciferase reporter assay confirmed that RyR2 is a direct target gene of miR-133a in B/TSMCs. Finally, we conclude that MALAT1 knockdown could protect from B/TSMCs injury via regulating miR-133a/ RyR2 axis.

MALAT1 knockdown promoted cell viability and migration of LPS-treated MG-63 cells via sponging miR-212.

Most fractures could heal after treatment, around 5-10 % of patients still develop delayed union and nonunion. Evidence has increasingly shown that abnormal expression of long noncoding RNAs is closely related to the occurrence and development of various diseases including fracture healing. However, evidence regarding the effect of MALAT1 on fracture healing remains limited. In this study, we attempt to explore the role of MALAT1 during the process of femoral neck fracture healing and elucidate the underlying mechanism of this disease. We first detect the expression of lncRNAs in serums from 3 pairs of patients with delayed femoral neck fracture healing and healthy volunteers using lncRNA microarray. And the expression of long noncoding RNA MALAT1 in serums and LPS-treated MG-63 cells was measured using qRT-PCR. CCK-8 assay, cell migration and qRT-PCR were applied to the role of MALAT1 knockdown in LPS-treated MG-63 cells. ELISA was used for the measurement of inflammatory cytokines in serums of patients and healthy volunteers. The bioinformatics analysis and the rescue experiment were devoted to the underlying mechanism. MALAT1 expression was up-regulated in serum of patients with delayed union of femoral neck fracture. MALAT1 knockdown promoted cell viability and migration, reduced inflammation in LPS-treated MG-63 cells. The bioinformatics analysis showed MALAT1 acts as a molecular sponge for miR-212. And SOX6 was a target of miR-212. Besides, MALAT1 knockdown suppressed SOX6 expression via targeting miR-212 in LPS-treated MG-63 cells. These data suggest MALAT1 knockdown promoted the biological behavior of LPS-treated MG-63 cells via sponging miR-212, which may provide a new therapeutic avenue for delayed union of femoral neck fracture.

The long noncoding RNA MALAT1 modulates adipose loss in cancer-associated cachexia by suppressing adipogenesis through PPAR-\u03b3

BackgroundCancer-associated cachexia is a multifactorial syndrome defined by progressive weight loss with ongoing loss of adipose tissue and skeletal muscle. Adipose loss occurs in the early stage of cachexia and is associated with reduced quality of life and survival time. Although numerous lncRNAs are regarded as novel regulators in adipose metabolism, the role of lncRNAs that selectively modulate the development of adipose loss in cachexia remains limited.MethodsIn this study, we analyzed microarray data of lncRNAs in adipose loss and further explored the function and mechanism of MALAT1 in adipose loss. First, we explored the expression and function of MALAT1 in adipose cell by quantitative PCR and RNA knockdown. Subsequently, the mechanism of MALAT1 involvement in adipose loss was analyzed via RNA-seq, bioinformatics analysis and reporter gene assay. Finally, we explored the clinical significance of MALAT1 through correlation analysis.ResultsCellular experiments revealed that knocking down MALAT1 significantly inhibited the process of adipogenesis. RNA-seq data showed that numerous adipogenic genes were downregulated upon MALAT1 knockdown. A protein–protein interaction network analysis identified PPAR-γ as the central node transcription factor, the inhibition of which explains the downregulation of numerous adipogenic genes. A reporter gene assay suggested that MALAT1 can regulate the gene expression of PPAR-γ at the transcriptional level. Moreover, MALAT1 was weakly expressed in the subcutaneous white adipose tissue of cancer-associated cachexia patients and was related to low fat mass index and poor prognosis in cancer patients.ConclusionsThis study indicated that MALAT1 is associated with adipose loss in cancer-associated cachexia by regulating adipogenesis through PPAR-γ, which may potentially be a novel target for the diagnosis and treatment of cancer-associated cachexia in the clinic.

The lncRNA Malat1 regulates microvascular function after myocardial infarction in mice via miR-26b-5p/Mfn1 axis-mediated mitochondrial dynamics

RationaleMyocardial infarction (MI) is a leading cause of cardiovascular mortality globally. The improvement of microvascular function is critical for cardiac repair after MI. Evidence now points to long non-coding RNAs (lncRNAs) as key regulators of cardiac remodelling processes. The lncRNA Malat1 is involved in the development and progression of multiple cardiac diseases. Studies have shown that Malat1 is closely related to the regulation of endothelial cell regeneration. However, the potential molecular mechanisms of Malat1 in repairing cardiac microvascular dysfunction after MI remain unreported. Methods and resultsThe present study found that Malat1 is upregulated in the border zone of infarction in mouse hearts, as well as in isolated cardiac microvascular endothelial cells (CMECs). Targeted knockdown of Malat1 in endothelial cells exacerbated oxidative stress, attenuated angiogenesis and microvascular perfusion, and as a result decreased cardiac function in MI mice. Further studies showed that silencing Malat1 obviously inhibited CMEC proliferation, migration and tube formation, which was at least in part attributed to disturbed mitochondrial dynamics and activation of the mitochondrial apoptosis pathway. Moreover, bioinformatic analyses, luciferase assays and pull-down assays indicated that Malat1 acted as a competing endogenous RNA (ceRNA) for miR-26b-5p and formed a signalling axis with Mfn1 to regulate mitochondrial dynamics and endothelial functions. Overexpression of Mfn1 markedly reversed the microvascular dysfunction and CMEC injuries that were aggravated by silencing Malat1 via inhibition of excessive mitochondrial fragments and mitochondria-dependent apoptosis. ConclusionsThe present study elucidated the functions and mechanisms of Malat1 in cardiac microcirculation repair after MI. The underlying mechanisms of the effects of Malat1 could be attributed to its blocking effects on miR-26b-5p/Mfn1 pathway-mediated mitochondrial dynamics and apoptosis.

LncRNA‑MALAT1 promotes highglucose‑induced H9C2 cardiomyocyte pyroptosis bydownregulating miR‑141‑3p expression.

Diabetic cardiomyopathy (DCM) is caused by diabetes and can result in heart failure. Long non-coding RNAs (lncRNAs) have been demonstrated to be closely associated with DCM development. The present study aimed to investigate whether lncRNA-metastasis-associated lung adenocarcinoma transcript-1 (MALAT1) altered high glucose (HG)-induced H9C2 cardiomyocyte pyroptosis by targeting microRNA (miR)-141-3p. H9C2 cells were treated with normal glucose (NG) or HG. lncRNA-MALAT1 and miR-141-3p expression levels were determined via reverse transcription-quantitative PCR (RT-qPCR). MALAT1 and miR-141-3p knockdown and overexpression were established and confirmed via RT-qPCR. The association between MALAT1 expression and miR-141-3p expression, as well as the induction of pyroptosis and gasdermin D (GSDMD)-N expression were evaluated by performing dual luciferase reporter, TUNEL staining and immunofluorescence staining assays, respectively. Western blotting was conducted to measure the expression levels of pyroptosis-associated proteins, including apoptosis-associated speck-like protein, GSDMD-N, caspase-1, nucleotide oligomerization domain-like receptor protein 3 and GSDMD. MALAT1 mRNA expression levels were significantly increased, whereas miR-141-3p expression levels were significantly decreased in HG-treated H9C2 cells compared with the NG group. Compared with the HG group, MALAT1 overexpression significantly reduced miR-141-3p expression levels, increased the rate of TUNEL positive cells and upregulated the expression levels of pyroptosis-associated proteins. MALAT1 knockdown displayed the opposite effect on the rate of TUNEL positive cells and the expression levels of pyroptosis-associated proteins. Furthermore, the rate of TUNEL positive cells, and GSDMD-N and pyroptosis-associated protein expression levels were significantly reduced by miR-141-3p overexpression in MALAT1-overexpression H9C2 cells. The results indicated that compared with NG treatment, HG treatment increased MALAT1 expression levels and decreased miR-141-3p expression levels in H9C2 cells. Therefore, the present study suggested that lncRNA-MALAT1 targeted miR-141-3p to promote HG-induced H9C2 cardiomyocyte pyroptosis.

The lncRNA MALAT1 participates in regulating coronary slow flow endothelial dysfunction through the miR-181b-5p–MEF2A–ET-1 axis

BackgroundCoronary slow flow (CSF) refers to coronary arteries with no obvious stenosis but have slow coronary flow without effective treatment. The main cause of CSF is endothelial dysfunction. The long non-coding RNA (lncRNA) MALAT1 is involved in regulating endothelial dysfunction, but its role in CSF endothelial dysfunction is still unclear. MethodsWe included 41 CSF patients and 37 controls in the study, who all underwent coronary angiography, echocardiography, and brachial artery flow-mediated dilatation (FMD) examination. Human umbilical vein endothelial cells (HUVECs) stimulated by oxygen–glucose deprivation were used as CSF-induced HUVECs. Plasma endothelin-1 (ET-1) concentrations were determined by enzyme-linked immunosorbent assay (ELISA). The expression levels of MALAT1, miR-181b-5p, myocyte enhancer factor 2A (MEF2A), and ET-1 were measured by qRT-PCR or western blotting. Cell proliferation was determined by 5-ethynyl-2′-deoxyuridine (EdU) and Cell Counting Kit-8 (CCK-8) assays. Apoptosis was examined by flow cytometry. The relationship between miR-181b-5p and MALAT1 or MEF2A was verified by dual-luciferase reporter assay. MEF2A binding directly to the ET-1 promoter region was verified via chromatin immunoprecipitation (ChIP) assay. ResultsMALAT1 and ET-1 were increased, and miR-181b-5p was decreased in the peripheral blood of the CSF patients, and could be used as predictors of CSF. In the CSF-induced HUVECs, MALAT1 was highly expressed, and MALAT1 knockdown improved endothelial function. In contrast, miR-181b-5p was downregulated in the CSF-induced HUVECs, and miR-181b-5p overexpression improved endothelial function. While MEF2A was highly enriched in CSF-induced HUVECs, MEF2A knockdown reduced ET-1 and increased the endothelial function of CSF-induced HUVECs as a transcriptional regulator of ET-1. MALAT1 modulated MEF2A expression positively by sponging miR-181b-5p. ConclusionsEndothelial function is reduced in CSF. MALAT1 participates in regulating CSF endothelial dysfunction through the miR-181b-5p–MEF2A–ET-1 axis, and could provide a new target for CSF treatment.

RETRACTED ARTICLE: Targeting MALAT1 and miRNA-181a-5p for the intervention of acute lung injury/acute respiratory distress syndrome

BackgroundALI/ARDS is a severe lung injury leading to refractory respiratory failure, accounting for high morbidity and mortality. However, therapeutic approaches are rather limited. Targeting long non-coding RNA MALAT1 and microRNA miR-181a-5p might be potential option for ALI/ARDS intervention.ObjectiveWe aimed to investigate the role of MALAT and miR-181a-5p in the pathogenesis of ALI/ARDS, and test the therapeutic effects of targeting MALAT and miR-181a-5p for ALI/ARDS intervention in vitro.MethodsMALAT1 and miR-181a-5p levels were measured in plasma from ALI/ARDS patients. In vitro human pulmonary microvascular endothelial cell (HPMEC) injury was induced by LPS treatment, and molecular targets of MALAT1 and miR-181a-5p were explored by molecular biology approaches, mainly focusing on cell apoptosis and vascular inflammation. Interaction between MALAT1 and miR-181a-5p was also detected. Finally, the effects of targeting MALAT1 and miR-181a-5p for ALI/ARDS intervention were validated in a rat ALI/ARDS model.ResultsMALAT1 upregulation and miR-181a-5p downregulation were observed in ALI/ARDS patients. Transfection of mimic miR-181a-5p into HPMECs revealed decreased Fas and apoptosis, along with reduced inflammatory factors. Fas was proved to be a direct target of miR-181a-5p. Similar effects were also present upon MALAT1 knockdown. As for the interaction between MALAT1 and miR-181a-5p, MALAT1 knockdown increased miR-181a-5p expression. Knocking down of MALAT1 and miR-181a-5p could both improve the outcome in ALI/ARDS rats.ConclusionMALAT1 antagonism or miR-181a-5p could both be potential therapeutic strategies for ALI/ARDS. Mechanistically, miR-181a-5p directly inhibits Fas and apoptosis, along with reduced inflammation. MALAT1 negatively regulates miR-181a-5p.

MicroRNA miR-188-5p as a mediator of long non-coding RNA MALAT1 regulates cell proliferation and apoptosis in multiple myeloma

ABSTRACT Multiple myeloma (MM), a malignancy of plasma cells mainly derived from the bone marrow, has remained incurable generally. LncRNA MALAT1 has been reported to be upregulated in the MM cells and knockdown of MALAT1 inhibited MM cell cycle progression and enhanced cell apoptosis. Online target prediction showed that two target sites for MALAT1 existed in miR-188-5p, which has been identified as a tumor suppressor in other types of cancers. However, the role of miR-188-5p in the MM and whether miR-188-5p mediates the MM tumor progression regulated by MALAT1 are still unknown. Herein, four main MM cell lines were adopted to investigate the effects of miR-188-5p on cell proliferation and apoptosis via transfection with miR-188-5p mimic/inhibitor and co-transfection with miR-188-5p inhibitor and MALAT1-shRNA plasmids. Xenograft tumor model was also established to study these effects in vivo. Overexpression of miR-188-5p inhibited cell viability, cell proliferation as well as tumor growth and arrested cell cycle at G1 to S transition, but miR-188-5p knockdown showed opposite effects on the MM cells in vitro and in vivo. Moreover, MALAT1 was shown to be inversely correlated with miR-188-5p expression through direct binding to miR-188-5p, and in turn, miR-188-5p could mediate the MM cell proliferation and apoptosis regulated by MALAT1. These findings indicate that miR-188-5p serves as a tumor suppressor in the progression of the MM and is directly involved in MM cell proliferation and apoptosis regulated by MALAT1, which may provide a potential therapeutic target or prognostic indictor for MM clinical treatment.

LncRNA MALAT1-deficiency restrains lipopolysaccharide (LPS)-induced pyroptotic cell death and inflammation in HK-2 cells by releasing microRNA-135b-5p

Long non-coding RNAs (LncRNAs) participate in the regulation of chronic kidney disease (CKD), and acute kidney injury (AKI) is identified as an important risk factor for CKD. This study investigated the involvement of a novel LncRNA MALAT1 in regulating lipopolysaccharide (LPS)-induced cell pyroptosis and inflammation in the human renal tubular epithelial HK-2 cells. Here, the HK-2 cells were subjected to LPS (2 μg/mL) treatment to establish cellular AKI models in vitro, and we validated that LPS triggered NLRP3-mediated pyroptotic cell death, promoted cell apoptosis and inflammation-associated cytokines secretion to induce HK-2 cell injury. Then, a novel LncRNA MALAT1/miRNA (miRNA)-135b-5p axis was verified to rescue cell viability in LPS treated HK-2 cells by targeting NLRP3. Mechanistically, miRNA-135b-5p bound to LncRNA MALAT1, and LncRNA MALAT1 positively regulated NLRP3 through acting as RNA sponger for miRNA-135b-5p. Further gain- and loss-of-function experiments evidenced that both LncRNA MALAT1 ablation and miRNA-135b-5p overexpression reversed LPS-induced cell pyroptosis, apoptosis, and inflammation in the HK-2 cells, and the protective effects of LncRNA MALAT1 knock-down on LPS-treated HK-2 cells were abrogated by silencing miRNA-135b-5p. In general, our study firstly investigated the role of the LncRNA MALAT1/ miRNA-135b-5p/NLRP3 signaling cascade in regulating LPS-induced inflammatory death in HK-2 cells.

Long Noncoding RNA MALAT1 Promotes Colorectal Cancer Progression by Acting as a ceRNA of miR-508-5p to Regulate RAB14 Expression.

Accumulating evidence suggested that lncRNA MALAT1 plays critical roles in the commencement and progression of malignant cancers. Nevertheless, the function of MALAT1 in colorectal cancer (CRC) remains largely unknown. In the present study, we reported that MALAT1 expression is significantly upregulated in CRC and correlated with advanced TNM stage, lymph node metastasis, and worse prognosis in patients. Functional assays revealed that MALAT1 knockdown reduced CRC cell growth and invasion abilities in vitro. Mechanistically, we discovered that MALAT1 may serve as a competing endogenous RNA (ceRNA) to miR-508-5p in CRC progression. Bioinformatics analysis and luciferase assays confirmed that RAB14 acts as a target of miR-508-5p. In addition, downregulation of RAB14 reduced the progression of CRC. Collectively, our findings indicated that MALAT1 could promote CRC progress by sponging miR-508-5p and enhancing RAB14 expression, which provides a therapeutic target in CRC treatment.

RETRACTED: Targeting MALAT1 and miRNA-181a-5p for the intervention of acute lung injury/acute respiratory distress syndrome

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).This article has been retracted at the request of the authors due to a reported lack of agreement among the authors. The usage of the image in E-b part of Figure 7 had not received permission from the co-author. In order to resolve the issue, the authors agreed to retract the article.

LncRNA MALAT1 promotes wound healing via regulating miR-141-3p/ZNF217 axis.

BackgroundThe process of wound healing is complex. Increasing evidences have shown that lncRNA MALAT1 is abundant in fibroblasts and may be engaged in wound healing process. Therefore, we explored the mechanism of MALAT1 affecting wound healing.MethodsThe expression levels of MALAT1, miR-141-3p as well as ZNF217 in human fibroblast cells (HFF-1) were quantified by qRT-PCR. HFF-1 proliferation was measured by MTT, while migration was detected by wound healing assay. SMAD2 activation and matrix proteins expression were detected by western blotting. The interaction between miR-141-3p and MALAT1 or ZNF217 was further confirmed using the luciferase reporter gene assay. In vivo wound healing was assessed by full-thickness wound healing model on C57BL/6 mice.ResultKnockdown of MALAT1 as well as overexpression miR-141-3p remarkably inhibited the proliferation, migration and matrix protein expression in HFF-1 cells. MALAT1 directly targeted and inhibited the expression of miR-141-3p. MiR-141-3p suppressed the activation of TGF-β2/SMAD2 signaling pathway by targeting ZNF217. Knockdown of MALAT1 inhibited wound healing process in mice.ConclusionsMALAT1 up-regulates ZNF217 expression by targeting miR-141-3p, thus enhances the activity of TGF-β2/SMAD2 signaling pathway and promotes wound healing process. This investigation shed new light on the understanding of the role of MALAT1 in wound healing, and may provide potential target for the diagnosis or therapy of chronic wounds.

LncRNA MALAT1 Promotes STAT3-Mediated Endothelial Inflammation by Counteracting the Function of miR-590

The excessive production of inflammatory mediators by vascular endothelial cells (ECs) greatly contributes to the development of atherosclerosis. In this study, we explored the potential effect of lncRNA MALAT1 on endothelial inflammation. First, the EC inflammation model was constructed by treating human umbilical vein ECs (HUVECs) and human coronary artery ECs (HCAECs) with oxidized low-density lipoprotein (ox-LDL), which confirmed the role of MALAT1 in the inflammatory activity. Then MALAT1 was overexpressed in HUVECs and HCAECs, and the levels of inflammatory mediators and nitric oxide (NO) were examined by Western blotting, ELISA, and NO detection assay. The migration ability was confirmed by wound healing assay. The interactions among MALAT1, miR-590, and STAT3 were predicted by bioinformatics analysis and verified by qRT-PCR, Western blotting, or dual-luciferase reporter assay. MALAT1 was upregulated in ECs treated with ox-LDL, and knockdown of MALAT1 significantly inhibited ox-LDL-induced inflammation. MALAT1 overexpression potentiated the inflammatory activities of ECs, including enhanced production of inflammatory cytokines (IL-6, IL-8, and TNF-α) and adhesion molecules (VCAM1 and ICAM1), and decreased NO level and cell migratory ability. Mechanistically, MALAT1 could directly downregulate miR-590, and miR-590 could bind to the 3′-UTR of STAT3 to repress its expression. Additionally, overexpression of MALAT1-mediated inflammation was largely abrogated by the concomitant overexpression of miR-590. miR-590 knockdown activated the inflammatory response, which was reversed by STAT3 inhibition. Thus, MALAT1 serves as a proinflammatory lncRNA in ECs through regulating the miR-590/STAT3 axis, suggesting that MALAT1 may be a promising therapeutic target during the treatment of atherosclerosis.