LncRNA-N1LR Enhances Neuroprotection Against Ischemic Stroke Probably by Inhibiting p53 Phosphorylation

155

102

Background/Aims: LncRNA metastasis associated lung adenocarcinoma transcript 1 (MALAT1) was reported to be highly expressed in an in vitro mimic of ischemic stroke conditions. However, the exact biological role of MALAT1 and its underlying mechanism in ischemic stroke remain to be elucidated. Methods: The roles of MALAT1 and miR-30a on cell death and infarct volume and autophagy were evaluated in experimental ischemic stroke. The relationships between miR-30a and MALAT1, Beclin1 were confirmed by luciferase reporter assay. The autophagy inhibitor 3-methyadenine (3-MA) was used to examine the impact of autophagy on ischemic injury. Results: We found that MALAT1, along with the levels of conversion from autophagy-related protein microtubule-associated protein light chain 3-I (LC3-I) to LC3-phosphatidylethanolamine conjugate (LC3-II), as well as Beclin1 were up-regulated and miR-30a was down-regulated in cerebral cortex neurons after oxygen-glucose deprivation (OGD) and mouse brain cortex after middle cerebral artery occlusion-reperfusion (MCAO). Down-regulation of MALAT1 suppressed ischemic injury and autophagy in vitro and in vivo. Furthermore, MALAT1 may serve as a molecular sponge for miR-30a and negatively regulate its expression. In addition, MALAT1 overturned the inhibitory effect of miR-30a on ischemic injury and autophagy in vitro and in vivo, which might be involved in the derepression of Beclin1, a direct target of miR-30a. Mechanistic analyses further revealed that autophagy inhibitor 3-methyadenine (3-MA) markedly suppressed OGD-induced neuronal cell death and MCAO-induced ischemic brain infarction. Conclusion: Taken together, our study first revealed that down-regulation of MALAT1 attenuated neuronal cell death through suppressing Beclin1-dependent autophagy by regulating miR-30a expression in cerebral ischemic stroke. Besides, our study demonstrated a novel lncRNA-miRNA-mRNA regulatory network that is MALAT1-miR-30a-Beclin1 in ischemic stroke, contributing to a better understanding the pathogenesis and progression of ischemic stroke.

Section: Discussionmentioning

confidence: 99%

Down-Regulation of Lncrna MALAT1 Attenuates Neuronal Cell Death Through Suppressing Beclin1-Dependent Autophagy by Regulating Mir-30a in Cerebral Ischemic Stroke

Guo¹,

Ma²,

Yan³

et al. 2017

155

102

“…Dharap performed microarray analysis of rat cerebral cortex and revealed that lncRNA expression profiles are significantly altered after stroke [7]. Wu [8] and Dharap [9] performed microarray analysis of rat brain tissues to identify and explore the potential function of lncRNA-N1LR. Bhattarai performed high-throughput sequencing in rat cerebral cortex and discovered novel stroke-associated lncRNAs [10].…”

Section: Introductionmentioning

confidence: 99%

Identification of Novel LncRNA Biomarkers and Construction of LncRNA-Related Networks in Han Chinese Patients with Ischemic Stroke

Guo

Yang

Liang

et al. 2018

Background/Aims: Long non-coding RNAs (lncRNAs) are potential biomarkers of tumors, cardiac disease, and cerebral disease because of their interaction with coding RNAs. This work focused on ischemic stroke (IS) and aimed to identify novel lncRNA biomarkers and construct lncRNA-related networks in IS. Methods: Differentially expressed lncRNAs were identified using Arraystar Human LncRNA Microarray v4.0, and validated with qRT-PCR. A lncRNA–mRNA co-expression network and a lncRNA–miRNA–mRNA regulatory network were constructed. Functional and pathway analyses were then performed. Results: In total, 560 up-regulated and 690 down-regulated differentially expressed lncRNAs were found (P < 0.05, false discovery rate < 0.05, absolute fold change ≥ 2). qRT-PCR results confirmed that lncRNA-ENST00000568297, lncRNA-ENST00000568243, and lncRNA-NR_046084 exhibited significant differential expression between IS and controls (all P < 0.05). Areas under the curves (AUCs) for these lncRNAs were 0.733, 0.743, and 0.690, respectively, and the combined AUC was 0.843. A coding–noncoding co-expression (CNC) network was constructed based on Pearson’s correlation coefficient. A specific lncRNA–miRNA–mRNA regulatory network of ENST00000568297, ENST00000568243, and NR_046084 was also constructed. Functional annotation of the up- and down-regulated mRNAs was performed. Pathway analysis enriched IS-related pathways with mRNAs in the lncRNA–miRNA–mRNA regulatory network. Conclusion: LncRNA and mRNA expression profiles in human peripheral blood were altered after IS. ENST00000568297, ENST00000568243, and NR_046084 were identified as novel potential diagnostic biomarkers of IS. Analysis of the CNC network and lncRNA–miRNA–mRNA regulatory network suggested that lncRNAs may participate in IS pathophysiology by regulating pivotal miRNAs, mRNAs, or IS-related pathways.

“…LncRNAs can suppress precursor mRNA splicing and translation by acting as decoys for RNA-binding proteins or miRNAs, or as competing endogenous RNAs to sponge miRNAs resulting in increased expression of corresponding proteins [18]. Although a series of lncRNAs has been reported to linked to neurodegenerative disorders including Alzheimer’s disease (AD), Parkinson’s disease (PD), and Huntington’s disease (HD), the role of lncRNAs in stroke remains unclear [19, 20]. …”

Section: Introductionmentioning

confidence: 99%

Maternally Expressed Gene 3 (MEG3) Enhances PC12 Cell Hypoxia Injury by Targeting MiR-147

Han

Dong

Liu

et al. 2017

Background/Aims: Cerebral ischemia often leads to breakdown of blood–brain barrier (BBB) and vasogenic edema. It remains to be established whether MEG3 is responsible for the hypoxic damage in neural cells. This study aimed to investigate the role of MEG3 in the hypoxia-induced injuries of PC12 cells. Methods: The PC12 cells were seeded and cultured under hypoxia and normoxia culture conditions. The cell viability determined by trypan blue exclusion, apoptosis using propidium iodide (PI) and fluorescein isothiocynate (FITC)-conjugated Annexin V staining, cell-migration using a modified two-chamber migration assay with a pore size of 8 µM and invasion using 24-well Millicell Hanging Cell Culture inserts with 8 µM PET membranes. Results: Cell viability, relative migration and relative invasion decreased significantly in PC12 cells injured due to hypoxia as compared to control cells. An increase in apoptosis was also observed. The expression of MEG3 was up-regulated in hypoxia-injured PC12 cells. MEG3 overexpression enhanced hypoxia injuries, while MEG3 suppression attenuated the injuries. Meanwhile, MEG3 negatively regulated miR-147 expression. In addition, we found that the expression of Sox2 was increased in PC12 cells after hypoxia and miR-147 negatively regulated Sox2 expression through targets its 3’-UTR. Interesting, Sox2 activated NF-κB pathway and Wnt/β-catenin pathway in PC12 cells. Conclusion: Considering the observations in our study, we can conclude that MEG3 aggravated the hypoxial injury in PC12 cells by down-regulating miR-147 gene and miR-147 further negatively regulated Sox2 expression.