Transcriptome-Wide Analysis to Identify the Inflammatory Role of lncRNA Neat1 in Experimental Ischemic Stroke

Abstract

Background Ischemic stroke is one of the leading causes of mortality and disability worldwide. Following stroke, there is secondary neuroinflammation that promotes further injury. Identifying the long non-coding RNA (lncRNA) involved in neuroinflammation after cerebral ischemic stroke will promote the discovery of potential therapeutic targets. Methods We identified differentially expressed genes from genome-wide RNA-seq profiles of mice with focal ischemia using Gene Ontology Term Enrichment, Kyoto Encyclopedia of Genes and Genomes, and Gene Set Enrichment analyses. Immune cell infiltration deconvolution, protein-protein interaction network construction, and co-expression network analyses were also used to screen lncRNAs. In further experiments, lncRNA Neat1 knockdown animal models were developed by intraventricular injection of the antisense oligonucleotide before performing middle cerebral artery occlusion (MCAO). An enzyme-linked immunosorbent assay was performed to measure the level of cytokines. Hematoxylin-eosin staining and immunohistochemical staining were used to observe the changes in morphology. Results Enrichment analysis revealed that differential mRNAs induced neuroinflammation after MCAO. Immune deconvolution showed that the proportion of microglia gradually increased while monocytes decreased within 24 h. We identified six hub lncRNAs ( Neat1 , Gm10827 , Trp53cor1 , Mir670hg , C730002L08Rik , and Mir181a-hg ) that were highly correlated with activated-microglia mRNAs (cor > 0.8). We found that Neat1 had the highest correlation coefficient with pro-inflammatory factor mRNA levels. In vivo experiments demonstrated that Neat1 had abnormally high expression after MCAO. Knockdown of Neat1 could significantly alleviate brain damage by reducing the number of activated microglia and reducing their release of proinflammatory cytokines. Conclusion We identified inflammation-associated lncRNA Neat1 as crucial, which means it is a potential target for ischemic stroke treatment.

Novel Insights into the Emerging Role of Neat1 and Its Effects Downstream in the Regulation of Inflammation

“…Of these 15 studies, 5 on stroke, 6 on PD, 2 on spinal cord injury (SCI), and 1 on traumatic brain injury with the last one on epilepsy study, suggesting that it is sufficient to illustrate that Neat1 can modulate inflammation in the CNS disorders. Up on stroke condition, an upregulation of Neat1 was uncovered in ischemic stroke patients’ blood, 61 animals with an MCAO, 60 and in vitro cells with hypoxia. 50 Similarly, the upregulation of Neat1 has a detrimental effect and accelerates disease progression in PD via regulating inflammation.…”

“… 123 , 131 , 132 Ni et al 62 exposed Neat1 knockdown BV-2 cells to oxygen–glucose deprivation/reoxygenation (OGD/R) and then detected the various levels of markers of M1 (CD16, CD32, and CD86) and M2 (BDNF, PDGF, and Arg-1) microglia, demonstrating that Neat1 knockdown suppresses M1microglial polarization but does not promote M2 microglial polarization. Jin et al 60 revealed that microglia had shorter ramifies and larger cell bodies after MCAO; however, the antisense oligonucleotides (ASO)-Neat1 group (Neat1 knockdown) was associated with significantly fewer activated microglia. Also, pyknotic nuclei and vacuolated cytoplasm were markedly reduced in the cortex and striatum of ASO-Neat1 mice.…”

“…The process was iterated until no more publications would be obtained. A total of 15 publications were identified in this section, [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] which were performed between 2017 and 2021. The most widely used species and related inflammatory models are mice and middle cerebral artery occlusion (MCAO), respectively.…”

LncRNA, an Emerging Approach for Neurological Diseases Treatment by Regulating Microglia Polarization

“…In a mouse model of ischemia, downregulation of H19 may reduce ischemic injury by inhibiting HDAC1 expression and thereby polarizing microglia to M2 type ( Wang et al, 2017 ). LncRNANEAT1 is also significantly expressed in ischemic stroke patients, and according to genome-wide RNA-seq studies, it may promote microglia activation ( Jin et al, 2021 ). Knockdown of lncRNA nuclear-enriched abundant transcript 1 (NEAT1) reduces the activity of the proinflammatory AKT/STAT3 pathway and inhibits microglia activation, reducing ischemia-reperfusion-induced injury ( Ni et al, 2020 ).…”

Network Pharmacology and Bioinformatics Methods Reveal the Mechanism of Berberine in the Treatment of Ischaemic Stroke

“…Recent studies have shown that lncRNAs, as endogenous small molecules, are extensively involved in the pathogenesis of ischaemic stroke [ 6 – 8 ]. A clinical study has found that the Rs217727 polymorphism of the lncRNA H19 gene is closely related to susceptibility to ischaemic stroke and can be used as a potential marker of ischaemic stroke [ 9 ].…”