Expression Of lncRNA MEG3 Research Articles

LncRNA MEG3 suppresses erastin-induced ferroptosis of chondrocytes via regulating miR-885-5p/SLC7A11 axis.

Ferroptosis is involved in osteoarthritis development; however, the roles of long noncoding RNAs (lncRNAs), including lncRNA MEG3, in the regulation of ferroptosis in osteoarthritis are still unclear. In this study, qRT‒PCR and Western blotting assays were used to detect the expression of lncRNA MEG3, miR-885-5p, SLC7A11 and GPX4; MDA and CCK-8 assays were applied to analyse cellular MDA levels and cell viability, respectively. Erastin elevated cellular MDA levels and decreased the viability of chondrocytes and the erastin-induced decline in cell viability was reversed by a ferroptosis inhibitor (ferrostatin-1). Erastin downregulated lncRNA MEG3, SLC7A11 and GPX4 and upregulated miR-885-5p. Silencing of lncRNA MEG3 increased miR-885-5p and downregulated SLC7A11 and GPX4 and further sensitized chondrocytes to erastin-induced ferroptosis. In contrast, overexpression of lncRNA MEG3 had opposite effects. Dual luciferase assays confirmed binding between lncRNA MEG3 and miR-885-5p and between miR-885-5p and the 3'UTR of SLC7A11. In the synovial fluids from patients with osteoarthritis compared with synovial fluids from normal controls, the RNA levels of lncRNA MEG3 and SLC7A11 were decreased and the miR-885-5p expression level was increased. Our findings indicated that lncRNA MEG3 overexpression alleviated ferroptosis in chondrocytes by affecting the miR-885-5p/SLC7A11 signalling pathway.

The ceRNA Mechanism of lncRNA MEG3/miR-21-5p/SPRY2 in Cell Proliferation and Apoptosis in Bladder Cancer.

Bladder cancer (BC) is the second most common genitourinary malignancy. Long noncoding RNA (lncRNA) is implicated in BC progression. This study delved into the underlying mechanism of lncRNA MEG3 in BC. Bioinformatics analysis predicted the expression of lncRNA MEG3, its association with the survival of BC patients, its subcellular localization, and its binding sites with miR-21-5p. Differentially expressed genes (DEGs) in the GSE13507 chip were analyzed using GEOexplorer, downstream targets of miR-21-5p were predicted from databases, and the overlapping genes were analyzed by the website Venny2.1 (https://bioinfogp.cnb.csic.es/tools/venny/index.html); their impacts on patient survival were analyzed by the Starbase database. The expression of SPRY2 and TGFBI associated with patient survival was analyzed in TCGA. RT-qPCR and western blot were performed to detect levels of MEG3, miR-21-5p, and SPRY2 in BC/SV-HUC-1 cells. Malignant biological behaviors of BC cells were detected using CCK8, flow cytometry, and Transwell assays. RNA pull-down and dual-luciferase assays were employed to verify the binding relationship of miR-21-5p with MEG3 and SPRY2. MEG3 was found to be lowly expressed in BC cells and mainly distributed in the cytoplasm. Over-expression of MEG3 was found to inhibit BC cell activity, promote apoptosis, and reduce invasion and migration. miR-21-5p was found to be highly expressed in BC cells, and its down-regulation was found to inhibit the malignant behavior of BC cells. Over-expression of miR-21-5p was found to reverse the effect of pcDNA3.1-MEG3 on BC cells. MEG3 was found to competitively bind to miR-21-5p as a ceRNA to promote SPRY2 levels. LncRNA MEG3 promotes SPRY2 expression by competitively binding to miR-21-5p, thereby inhibiting proliferation and promoting apoptosis of BC cells.

LncRNA MEG3 promotes neuronal apoptosis in rats with ischemic cerebral infarction via the TGF-β1 pathway.

To study the influence of long non-coding ribonucleic acid maternally expressed gene 3 (lncRNA MEG3) on the neuronal apoptosis in rats with ischemic cerebral infarction, and to analyze its regulatory effect on the transforming growth factor-beta 1 (TGF-β1) pathway. A total of 36 Sprague-Dawley rats were randomly assigned into sham group, model group and low expression group. Ischemic cerebral infarction modeling was constructed in rats of the model group and low expression group. Corresponding adenoviruses were intracranially injected in rats of low expression group to knock down lncRNA MEG3 expression. At 24 h after the operation, the neurological function of rats was evaluated in each group, and the expression level of lncRNA MEG3 in cerebral tissues was determined using quantitative polymerase chain reaction (qPCR). The infarct size was measured via 2,3,5-triphenyltetrazolium chloride (TTC) staining. The apoptosis level of neurons in cerebral tissues was determined using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining. Besides, enzyme-linked immunosorbent assay (ELISA) was performed to determine the contents of inflammatory factors in cerebral tissues. Expression levels of apoptosis-associated proteins and vital genes in the TGF-β1 signaling pathway in rat cerebral tissues were measured using Western blotting. Compared with the sham group, rats in the model group exhibited substantial increases in the neurological score and apoptosis level of neurons (p<0.01). Relative levels of lncRNA MEG3, interleukin (IL)-6, tumor necrosis factor-alpha(TNF-α), Caspase-3, TGF-β1, small mothers against decapentaplegic homolog 2 (Smad2) and Smad3 (p<0.01) were higher in a model group than those in sham group. Notable declines in the content of IL-10 (p<0.01) and the ratio of B-cell lymphoma 2 (Bcl-2)/Bcl associated X protein (Bax) (p<0.01) were seen in the model group compared with the sham group. The abovementioned changes in the model group were partially abolished in the low expression group. LncRNA MEG3 is upregulated in the cerebral tissues of rats with ischemic cerebral infarction. It induces an inflammatory response, expands cerebral infarct size, and promotes neuronal apoptosis and impairment by activating the TGF-β1 pathway.

Correlation between plasma long non-coding RNA MEG-3 and inflammatory cytokines in patients with diabetic nephropathy.

To identify the correlation between the plasma long non-coding RNA maternally expressed gene 3 (lncRNA MEG-3) and inflammatory cytokines in patients with diabetic nephropathy (DN) and search for a potential index for the diagnosis of DN. Quantitative real-time PCR (qPCR) was used to assess lncRNA MEG-3 expression. The levels of plasma cytokines were detected via enzyme-linked immunosorbent assay (-ELISA). 20 patients with type 2 diabetes (T2DM) and DN (DM+DN+ group), 19 patients with T2DM (DM+DN- group), and 17 healthy subjects (DM-DN- group) were finally enrolled. The expression of lncRNA MEG-3 was significantly upregulated in the DM+DN+ group compared to the DM+DN- group (p < 0.05) and the DM-DN- group (p < 0.001). Pearson's correlation analysis showed a positive correlation of lncRNA MEG-3 levels with cystatin C (Cys-C) (r = 0.468, p < 0.05), albumin-creatinine ratio (ACR) (r = 0.532, p < 0.05), and creatinine (Cr) (r = 0.468, p < 0.05), and a negative correlation with estimated glomerular filtration rate (eGFR) (r = -0.674, p < 0.01). Furthermore, the expression level of plasma lncRNA MEG-3 had a significantly positive correlation with the level of interleukin 1β (IL-1β) (r = 0.524, p < 0.05) and interleukin 18 (IL-18) (r = 0.230, p < 0.05). Binary regression analysis showed that lncRNA MEG-3 was a risk factor for DN with odds ration (OR) value of 1.71 (p < 0.05). The area under receiver operation characteristic (ROC) curve (AUC) of DN identified by lncRNA MEG-3 was 0.724. LncRNA MEG-3 was highly expressed in DN patients and showed a positive correlation with IL-1β, IL-18, ACR, Cys-C, and Cr.

LncRNA MEG3 aggravates adipocyte inflammation and insulin resistance by targeting IGF2BP2 to activate TLR4/NF-κB signaling pathway.

Recently, emerging evidence has shown that LncRNA MEG3 is involved in adipocyte inflammation and insulin resistance progression, however, the specific mechanism of action remains unclear. In this study, we found that LncRNA MEG3 expression was increased in TNF-α stimulated 3T3-L1 mature adipocytes, and inflammatory factors IL-6 and MCP-1 secretion levels were increased, cell apoptosis and caspase3 activity was enhanced, ROS content was increased, and iNOS protein expression was increased. Moreover, TNF-α treatment attenuated glucose uptake, promoted triglyceride accumulation, inhibited GLUT4 protein expression at the plasma membrane, and reduced the phosphorylation levels of AMPK and ACC in the cells. Interestingly, we found that transfection of si-MEG3 reversed TNF-α caused inflammatory injury and insulin resistance of 3T3-L1 mature adipocytes. Next, we found that IGF2BP2 is an RNA binding protein of LncRNA MGE3 and transfection of si-IGF2BP2 reversed TNF-α caused inflammatory injury and insulin resistance in 3T3-L1 mature adipocytes, the same effects as transfection of si-MEG3. Mechanistically, LncRNA MGE3 was able to aggravate adipocyte inflammatory injury and dysregulation of insulin sensitivity by activating TLR4 pathway through upregulating the protein expression of IGF2BP2. In vivo findings showed that HFD mice with knockdown of MEG3 had reduced body weight, lower glucose concentrations and insulin levels in plasma, decreased inflammatory factors secretion, and reduced MEG3 and IGF2BP2 expression in epididymal adipose tissues and reduced fat accumulation in mice compared with HFD mice. Our results indicate that LncRNA MEG3 can aggravate chronic inflammation and insulin resistance in adipocytes by activating TLR4/NF-κB signaling pathway via targeting IGF2BP2.

HNRNPA2B1-mediated m6A modification of lncRNA MEG3 facilitates tumorigenesis and metastasis of non-small cell lung cancer by regulating miR-21-5p/PTEN axis

BackgroundAccumulating data indicate that N6-methyladenosine (m6A) RNA methylation and lncRNA deregulation act crucial roles in cancer progression. Heterogeneous nuclear ribonucleoprotein A2B1 (HNRNPA2B1) as an m6A “reader” has been reported to be an oncogene in multiple malignancies. We herein aimed to elucidate the role and underlying mechanism by which HNRNPA2B1-mediated m6A modification of lncRNAs contributes to non-small cell lung cancer (NSCLC).MethodsThe expression levels of HNRNPA2B1 and their association with the clinicopathological characteristics and prognosis in NSCLC were determined by RT-qPCR, Western blot, immunohistochemistry and TCGA dataset. Then, the role of HNRNPA2B1 in NSCLC cells was assessed by in vitro functional experiments and in vivo tumorigenesis and lung metastasis models. HNRNPA2B1-mediated m6A modification of lncRNAs was screened by m6A-lncRNA epi-transcriptomic microarray and verified by methylated RNA immunoprecipitation (Me-RIP). The lncRNA MEG3-specific binding with miR-21-5p was evaluated by luciferase gene report and RIP assays. The effects of HNRNPA2B1 and (or) lncRNA MEG3 on miR-21-5p/PTEN/PI3K/AKT signaling were examined by RT-qPCR and Western blot analyses.ResultsWe found that upregulation of HNRNPA2B1 was associated with distant metastasis and poor survival, representing an independent prognostic factor in patients with NSCLC. Knockdown of HNRNPA2B1 impaired cell proliferation and metastasis in vitro and in vivo, whereas ectopic expression of HNRNPA2B1 possessed the opposite effects. Mechanical investigations revealed that lncRNA MEG3 was an m6A target of HNRNPA2B1 and inhibition of HNRNPA2B1 decreased MEG3 m6A levels but increased its mRNA levels. Furthermore, lncRNA MEG3 could act as a sponge of miR-21-5p to upregulate PTEN and inactivate PI3K/AKT signaling, leading to the suppression of cell proliferation and invasion. Low expression of lncRNA MEG3 or elevated expression of miR-21-5p indicated poor survival in patients with NSCLC.ConclusionsOur findings uncover that HNRNPA2B1-mediated m6A modification of lncRNA MEG3 promotes tumorigenesis and metastasis of NSCLC cells by regulating miR-21-5p/PTEN axis and may provide a therapeutic target for NSCLC.

Long non-coding RNA maternally expressed gene 3, miR-125a-5p, CXCL13, and NF-kB in patients with immune thrombocytopenia

The main aim of this study was to assess the expression level of circulating long non-coding RNA maternally expressed gene 3 (lncRNA-MEG3), microRNA (miR-125a-5P), the chemokine C-X-C motif ligand13 (CXCL13), and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) in immune thrombocytopenia (ITP) cases and to study its relation to the disease severity and treatment response. This case-control study included 45 patients newly diagnosed as ITP and 45 healthy subjects. We assessed complete blood count, antinuclear antibodies, hepatitis B and C virus serology, lncRNA-MEG3, miR-125a-5P, and CXCL13 expression in serum by real-time PCR and NF-kb protein by ELISA. In ITP patients compared to control, lncRNA-MEG3 was significantly increased, and miRNA-125a-5P was decreased, and this was associated with higher CXCL13 and NF-kB levels (P < 0.001, for all).There was a significant negative correlation between platelet count and lncRNA-MEG3, CXCL13, and NF-kb, while a positive correlation with miR-125a-5p in ITP patients. Patients who responded to steroids had significantly higher miR-125a-5p (P = 0.016) and significantly lower lncRNA-MEG3 (P < 0.001), CXCL13 (P = 0.005), and NF-kb (p = 0.002). Based on the ROC curves, lncRNA-MEG3 displayed the highest area under the curve (AUC) in the identification of organ bleeding (AUC = 0.805), the response to steroids (AUC = 0.853), and the need for splenectomy (AUC = 0.75).

The Transgene Expression of the Immature Form of the HCV Core Protein (C191) and the LncRNA MEG3 Increases Apoptosis in HepG2 Cells.

Long non-coding RNAs (lncRNAs) are regulated in cancer cells, including lncRNA MEG3, which is downregulated in Hepatocellular Carcinoma (HCC). In addition, hepatitis C virus (HCV) core proteins are known to dysregulate important cellular pathways that are linked to HCC development. In this study, we were interested in evaluating the overexpression of lncRNA MEG3, either alone or in combination with two forms of HCV core protein (C173 and C191) in HepG2 cells. Cell viability was assessed by MTT assay. Transcripts’ levels of key genes known to be regulated in HCC, such as p53, DNMT1, miRNA152, TGF-b, and BCL-2, were measured by qRT-PCR. Protein expression levels of caspase-3 and MKI67 were determined by immunocytochemistry and apoptosis assays. The co-expression of lncRNA MEG3 and C191 resulted in a marked increase and accumulation of dead cells and a reduction in cell viability. In addition, a marked increase in the expression of tumor suppressor genes (p53 and miRNA152), as well as a marked decrease in the expression of oncogenes (DNMT1, BCL2, and TGF-b), were detected. Moreover, apoptosis assay results revealed a significant increase in total apoptosis (early and late). Finally, immunocytochemistry results detected a significant increase in apoptotic marker caspase-3 and a decrease in tumor marker MKI67. In this study, transgene expression of C191 and lncRNA MEG3 showed induction in apoptosis in HepG2 cells greater than the expression of each one alone. These results suggest potential anticancer characteristics.

Upregulation LncRNA MEG3 expression suppresses proliferation and metastasis in melanoma via miR-208/SOX4.

Long non-coding RNAs (lncRNAs) regulate gene expression and play a significant role in cancer progression. Previously, downregulation of lncRNA MEG3 was shown to associate with poor clinical outcomes in melanoma patients. The basis for this association has not been described and the aims of this study were to identify a role for lncRNA MEG3 in melanoma and to describe its regulatory mechanism of action. RT-qPCR was used to detect lncRNA MEG3 expression in melanoma cells and tissues. Luciferase reporter assays were used to identify lncRNA MEG3 downstream targets. Melanoma cells were transfected with various expression vectors and these transfected cells were assessed for; migration, colony formation, proliferation, in vivo tumorigenesis, and metastatic potential. Melanoma cell lines were found to be sensitive to lncRNA MEG3 expression levels and overexpression was found to inhibit melanoma cell proliferation and invasion, both in vitro and in vivo. Luciferase reporter assays identified miR-208 and SOX4 as downstream targets of lncRNA MEG3. Overexpression of miR-208 and silencing of SOX4 rescued invasion and proliferation by cells that overexpressed lncRNA MEG3. Moreover, lncRNA MEG3 inhibited cancer stem cell differentiation and suppressed melanoma progression and metastasis through inhibition of miR-208 by SOX4.

Long non-coding RNA MEG3 regulates the progress of osteoarthritis by regulating the miR-34a/Klotho axis.

BackgroundOsteoarthritis (OA) is one of the most common chronic diseases today, and its prevalence and incidence are expected to increase as life expectancy increases. By investigating the inhibition of long non-coding RNA maternally expressed gene 3 (lncRNA MEG3) in OA, we hope to provide some new insights into the treatment of osteoarthritis.MethodsBy constructing an osteoarthritis model, the knee joint tissue of the model was observed using hematoxylin and eosin staining (HE) and computed tomography (CT). Detection of miR-34a and Klotho expression by fluorescent quantitative polymerase chain reaction (PCR) and Western blot. The lncRNA MEG3 overexpression vector was constructed and transfected into C28/I2 cells. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used to detect the results of lncRNA MEG3 and miR-34a expression in each group of cells, and Western blot was used to detect the results of Klotho, recombinant fibroblast growth factor 23 (FGF23), B-cell lymphoma-2 (Bcl-2), BCL2-associated X (Bax), Transforming growth factor beta 1 (TGF-β1), cysteinyl aspartate specific proteinase 3 (Caspase3) and cysteinyl aspartate specific proteinase 8 (Caspase8) protein expression.ResultsCompared with the control group, HE and CT results showed significant pathological changes in the knee joint of the osteoarthritis model mice. and Klotho expression was significantly decreased and miR-34a expression was significantly increased in the model group (P<0.05). Compared with those in the control group, the expression levels of lncRNA MEG3, Klotho, FGF23, and Bcl-2 decreased significantly and the expression levels of microRNA-34a (miR-34a), Bax, TGF-β1, Caspase 3, and Caspase 8 increased sharply (P<0.05) in the lipopolysaccharides (LPS) group. Meanwhile, lncRNA MEG3 overexpression upregulated the expression of miR-34a, Bax, TGF-β1, Caspase3 and Caspase8, and downregulated the expression of Klotho, FGF23 and Bcl-2.ConclusionslncRNA MEG3 regulated the expression of FGF23, Bcl-2, Bax, TGF-β1, Caspase 3, and Caspase 8 by regulating the miR-34a/Klotho axis, thereby affecting the progress of OA.

LncRNA MEG3 promotes osteogenesis of hBMSCs by regulating miR-21-5p / SOD3 axis.

This study aimed to investigate the role of long non-coding (Lnc) RNA MEG3 on the osteogenesis of human bone marrow mesenchymal stem cells (hBMSCs). The binding of miR-21-5p to LncRNA MEG3 and SOD3 was determined using luciferase reporter assay; fluorescence quantitative PCR was used to detect the expression of LncRNA MEG3 at different induction times. hBMSCs were transfected with LncRNA MEG3 overexpression vector and induced for osteoblasts for 14 days. Alkaline phosphatase (ALP) staining, and alizarin red staining were used to detect bone differentiation, immunofluorescence assays were used to detect the expression of SOD3 and COL2A1. Luciferase reporter assay revealed that miR-21-5p bond to LncRNA MEG3 and SOD3. Flow cytometry analysis showed that hBMSCs were highly pure. After osteogenic induction for 14 days, compared with the control group, the overexpression of LncRNA MEG3 significantly increased the activity of ALP and enhanced the formation of calcium nodules in hBMSCs. The overexpression also increased the expression of COL2A1 and SOD3 significantly (P<0.05). LncRNA MEG3 can promote the osteogenesis and bone regeneration of hBMSCs and increasing the expression of SOD3 and COL2A1 via targeting the miR-21-5p/SOD3 axis.

Propofol Rescued Astrocytes from LPS-induced Inflammatory Response via Blocking LncRNA-MEG3/NF-κB Axis

Evidences demonstrate that propofol attenuates neuro-inflammation following brain ischemia. Moreover, LncRNA-MEG3 has been identified as an independent prognostic marker for ischemic stroke patients, and found to correlate to cerebral ischemia in animal models. Therefore, the current study explored the role of propofol in lipopolysaccharide (LPS)-mediated inflammation in cultured astrocytes, along with the molecular mechanism involved in LncRNAMEG3/ NF-κB axis. The primary cultured astrocytes isolated from rats were used to establish an inflammatory model, which were treated with LPS. Propofol was administrated to the primary cultured astrocytes during LPS treatment. The effects of propofol on pro-inflammatory cytokines and the LncRNAMEG3/ NF-κB pathway were detected by ELISA, qRT-PCR and Western Blot assay, respectively. Then, dual-luciferase assay, chromatin immunoprecipitation and RNA immunoprecipitation were used to determine the interaction between LncRNA-MEG3 and NF-κB. Our study found propofol to significantly reduce LncRNA-MEG3 expression, which was elevated in LPS-stimulated astrocytes. Moreover, both propofol and LncRNA-MEG3 knockdown remarkably alleviated LPS-induced cytotoxicity by suppressing expressions and release of proinflammatory cytokines. Loss of LncRNA-MEG3 notably suppressed the NF-κB activity and its phosphorylated activation. Additionally, it was also observed that LncRNA-MEG3 could bind nuclear p65/p50, and promote the binding of NF-κB to IL-6 and TNF-α promoters in the nucleus, subsequently stimulating the production of inflammatory cytokines in LPS-treated astrocytes. Furthermore, a specific inhibitor of NF-κB, PDTC, rescued astrocytes from LPS exposure without affecting the LncRNA-MEG3 expression. These findings demonstrate that LncRNA-MEG3 acts as a positive regulator of NF-κB, mediating the neuroprotection of propofol in LPS-triggered astrocytes injury.

Tumor suppressive lncRNA MEG3 binds to EZH2 and enhances CXCL3 methylation in gallbladder cancer.

Gallbladder cancer is a malignant tumor with a high mortality rate. Accumulating evidence supports that lncRNA MEG3 may halt the progression of gallbladder cancer, while the downstream mechanism is rarely studied. Thus, we aim to investigate the molecular basis of the tumor-suppressing role of lncRNA MEG3 in gallbladder cancer. The expression of lncRNA MEG3 and CXCL3 was measured in patient serum and cell lines of gallbladder cancer. The viability, apoptosis, migration, and invasion of gallbladder cancer cells were assessed following ectopic MEG3 expression, as detected by CCK-8, flow cytometry, and Transwell assays. The interaction among lncRNA MEG3, EZH2, and CXCL3 was explored through ChIP, RNA pull-down, and RIP assays. The effects of lncRNA MEG3 and CXCL3 on tumor growth were evaluated by a mouse xenograft model. lncRNA MEG3 was expressed at a low level in gallbladder cancer patient serum and cell lines, while CXCL3 was highly expressed. MEG3 overexpression repressed the malignant behaviors of gallbladder cancer cells and promoted their apoptosis. MEG3 was mainly localized in the nucleus. MEG3 bound to EZH2, and EZH2 catalyzed the H3K27 trimethylation of the CXCL3 promoter region. MEG3 downregulated CXCL3 by activating EZH2-mediated H3K27 trimethylation of CXCL3; MEG3 overexpression attenuated cancer cell malignant behaviors in vitro and suppressed tumor growth in vivo in gallbladder cancer by inhibiting CXCL3 expression. Altogether, our results indicate that lncRNA MEG3 impedes gallbladder cancer development via the EZH2-CXCL3 axis, offering potential biomarkers for gallbladder cancer management.

Tangshen Formula Attenuates Renal Fibrosis by Downregulating Transforming Growth Factor β1/Smad3 and LncRNA-MEG3 in Rats with Diabetic Kidney Disease

Abstract Background and Objective: The traditional Chinese Tangshen formula (TSF) has been reported to ameliorate diabetic kidney disease (DKD) in humans and animals. However, the effect of TSF on renal fibrosis remains unclear. Transforming growth factor-β1 (TGF-β1)/Smad3 signaling and lncRNA MEG3 are important in renal fibrosis. In this study, we examined the therapeutic effect of TSF on renal fibrosis and explored whether it was related to the modulation of TGFβ1/Smad3 signaling and lncRNA MEG3 expression. Materials and Methods: Experiments were performed in rats in vivo and in the HK2 cells in vitro. DKD was induced in rats by uninephrectomy combined with a single streptozotocin injection. The HK2 cells were stimulated by high glucose (HG) to explore the mechanism of TSF effects in vitro. Results: TSF significantly attenuated renal injury by lowering proteinuria and renal histological damage in DKD rats. TSF reduced collagen deposition by decreasing the expression of the fibrotic indicators collagen I, collagen IV, and fibronectin at the protein and mRNA levels, which suggested that TSF ameliorated DKD by decreasing renal fibrosis. Furthermore, TSF decreased TGF-β1 expression and suppressed the levels of phosphorylated Smad3 and Smad2/3 in vivo. Moreover, TSF downregulated the lncRNA MEG3 level in DKD rats. TSF reversed the upregulation of collagen I and fibronectin expression and downregulated Smad2/3 phosphorylation in the HK2 cells stimulated with HG. Conclusions: TSF ameliorates renal fibrosis in rats with DKD by suppressing TGF-β1/Smad3 signaling and lncRNA MEG3 expression.

LncRNA MEG3 suppresses PI3K/AKT/mTOR signalling pathway to enhance autophagy and inhibit inflammation in TNF-α-treated keratinocytes and psoriatic mice.

Psoriasis is a common chronic inflammatory skin disorder that causes patches of thick red skin and silvery scales and affects 1-3% of the population, which reduces patient's quality of life. Understanding the pathogenesis of psoriasis is crucial for developing novel therapeutic strategies. HaCaT and NHEK cells were treated with TNF-α in vitro. A mouse model of psoriasis was established by topical imiquimod application on back skin. LncRNA MEG3 was cloned into the pcDNA3.1 vector and transfected in TNF-α-treated HaCaT and NHEK cells to overexpress its expression. Liposome-encapsulated pcDNA3.1-MEG3 was injected into imiquimod-treated mice via tail vein. RT-qPCR and western blot assays were used to examine the expression of lncRNA MEG3, IL-6, IL-8, IFN-γ, IL-1β, LC3, Beclin 1, p62, p-p65, p65, NLRP3, p-PI3K, PI3K, p-AKT, AKT, p-mTOR, mTOR respectively. The secretion of IL-6, IL-8, IFN-γ and IL-1β was determined using ELISA assay. Immunofluorescence and immunohistochemistry methods were performed for analyzing the expression of LC3 and NLRP3 in cells and skin tissues respectively. LY294002 was used to block the PI3K/AKT/mTOR signalling. MTT assay was applied to test the toxicity of LY294002 to HaCaT and NHEK cells. LncRNA MEG3 expression levels were downregulated in TNF-α-treated HaCaT and NHEK cells and skin tissues of psoriatic mice model. TNF-α treatment enhanced inflammation and suppressed autophagy in HaCaT and NHEK cells, which were largely reversed by overexpression of lncRNA MEG3. Autophagy puncta and NLRP3 inflammasome assembly showed the same patterns with the expression of inflammation and autophagy markers in TNF-α-treated HaCaT and NHEK cells with or without lncRNA MEG3 overexpression. TNF-α-induced activation of the PI3K/AKT/mTOR signalling was abolished by lncRNA MEG3 overexpression in HaCaT and NHEK cells. Blocking the PI3K/AKT/mTOR signalling inhibited TNF-α-induced inflammation and restored autophagy level in TNF-α-treated HaCaT and NHEK cells. Overexpression of lncRNA MEG3 suppressed inflammation, promoted autophagy and inhibited the activation of the PI3K/AKT/mTOR signalling in a mouse model of psoriasis. LncRNA MEG3 facilitates autophagy and suppresses inflammation in TNF-α-treated keratinocytes and psoriatic mice, which is dependent on the PI3K/AKT/mTOR signalling pathway. Our study enhances the understanding of psoriasis and provides potential therapeutic targets for psoriasis.

LncRNA MEG3 promotes chemosensitivity of osteosarcoma by regulating antitumor immunity via miR-21-5p/p53 pathway and autophagy

This study aimed to investigate the role of long non-coding RNA maternally expressed gene 3 (lncRNA MEG3) in chemosensitivity of osteosarcoma (OS), and to reveal the possible underlying mechanisms. In this study, we found that the expression of lncRNA MEG3 was significantly lower in OS tissues and cell lines. Furthermore, lncRNA MEG3 overexpression enhanced chemosensitivity of OS by inhibiting cell proliferation, migration, autophagy, and promoting antitumor immunity. LncRNA MEG3 functioned as miR-21-5 sponge to regulate p53 expression in OS. Mechanically, lncRNA MEG3 promoted OS chemosensitivity by regulating antitumor immunity via miR-21-5p/p53 pathway and autophagy. Collectively, this study provided the evidence that lncRNA MEG3 might be a promising therapeutic target for OS chemoresistance.

Whole transcriptome sequencing identifies key circRNAs, lncRNAs, and miRNAs regulating neurogenesis in developing mouse retina

BackgroundThe molecular complexity of neural retina development remains poorly studied. Knowledge of retinal neurogenesis regulation sheds light on retinal degeneration therapy exploration. Therefore, we integrated the time-series circRNA, lncRNA, miRNA, and mRNA expression profiles of the developing retina through whole-transcriptome sequencing. The key functional ncRNAs and the ceRNA network regulating retinal neurogenesis were identified.ResultsTranscriptomic analysis identified circRNA as the most variable ncRNA subtype. We screened a series of neurogenesis-related circRNAs, lncRNAs, and miRNAs using different strategies based on their diversified molecular functions. The expression of circCDYL, circATXN1, circDYM, circPRGRIP, lncRNA Meg3, and lncRNA Vax2os was validated by quantitative real-time PCR. These circRNAs and lncRNAs participate in neurotransmitter transport and multicellular organism growth through the intricate circRNA/lncRNA-miRNA-mRNA network.ConclusionWhole-transcriptome sequencing and bioinformatics analysis systematically screened key ncRNAs in retinal neurogenesis. The validated ncRNAs and their circRNA/lncRNA-miRNA-mRNA network involve neurotransmitter transport and multicellular organism growth during retinal development.

Maternally expressed 3 inhibits the biological activity of oral squamous cell carcinoma SCC25 and CAL27 cell lines

The abnormal expression of long non-coding RNA (lncRNA) maternally expressed 3 (MEG3) is closely related to several tumor diagnosis and progression, such as endometrial carcinoma and ovarian cancer. However, the role of MEG3 in oral squamous cell carcinoma (OSCC) is rarely reported. The current study aimed to evaluate the expression of lncRNA MEG3 in OSCC tissues and cell lines and its effect on the biological behavior of OSCC cell lines. The expression of lncRNA MEG3 in the OSCC tissues and cell lines was detected by reverse transcription-quantitative (RT-q) PCR. The relationship between MEG3 expression and the clinicopathologic characteristics and prognosis of patients with OSCC was analyzed. The lncRNA MEG3 overexpression plasmid and control plasmid were transfected into SCC25 and CAL27 cell lines using the lipofectin method. MTT assay was performed to detect the growth and proliferation of the cell lines. Transwell chamber test was used to detect changes in cell migration and invasion. Flow cytometry was employed to detect changes in apoptosis. Western blotting and RT-qPCR were conducted to detect the expression of the p53 gene. The expression of lncRNA MEG3 in the OSCC tissues and cell lines was significantly compared with normal tissues and cell lines, respectively. The expression level of MEG3 was related to clinical stage, lymph node metastasis, distant metastasis and survival status. Overexpression of lncRNA MEG3 inhibited the proliferation, migration, and invasion of SCC25 and CAL27 cell lines, induced apoptosis and promoted the expression of p53 gene. lncRNA MEG3 played the role of a tumor inhibitor gene and significantly inhibited the biological activity of OSCC cell lines, which may provide a novel idea for molecular targeted therapy of OSCC.

Multiple time-point assessment of lncRNA MEG3 shows potential to monitor treatment efficacy in rheumatoid arthritis patients.

Background: This study explored the clinical role of lncRNA MEG3in rheumatoid arthritis (RA) management. Materials & methods: Totally, 191 active RA patients were enrolled, and their lncRNA MEG3 expressions in peripheral blood monoclonal cells were detected. Results: LncRNA MEG3 expression was downregulated, and it negatively correlated with lesion joints, inflammation and disease activity in RA patients. Moreover, lncRNA MEG3 expression was increased during treatment; meanwhile its increment correlated with treatment response and remission. Conclusion: LncRNA MEG3 may serve as a potential biomarker for monitoring treatment efficacy in RA management.

Tensile strain promotes osteogenic differentiation of bone marrow mesenchymal stem cells through upregulating lncRNA-MEG3.

With the aging of the population, osteoporosis is becoming more and more common. This progressive bone disease increases the risk of fractures and pain and causes serious harm to people's health and quality of life. Several studies, including our previous studies, confirmed that tensile strain can promote bone marrow mesenchymal stem cell (BMSC) osteogenic differentiation in vitro. In this study, we further explored the mechanism by which tensile strain regulates BMSC differentiation. A device designed by our group was used to apply tensile strain to BMSCs to study the effects of tensile strain on their differentiation. LncRNA-MEG3 overexpression and silencing models of BMSCs were constructed by lentivirus transfection to study the involvement of lncRNA-MEG3. We assessed osteogenic differentiation of BMSCs by alkaline phosphatase (ALP) staining and the expression of Runx2 mRNA and BMP2 mRNA, while adipogenic differentiation was evaluated by oil red staining and the expression of PPARγ mRNA and C/EBPα mRNA. We demonstrated that proper tensile strain can promote osteogenic differentiation of BMSCs while inhibiting differentiation into adipocytes, and simultaneously promote the expression of lncRNA-MEG3. The overexpression of lncRNA-MEG3 further promotes osteogenic differentiation of stressed BMSCs and inhibits expression of miR-140-5p; the knockdown of lncRNA-MEG3 induces the opposite effects. Appropriate mechanical stimulation can inhibit the expression of miR-140-5p by promoting lncRNA-MEG3 expression, thereby promoting the osteogenic differentiation of BMSCs. Our results provide a theoretical basis for physical exercise to improve the prevention and treatment of osteoporosis.