Protective effect of microRNA‑340‑5p against oxygen‑glucose deprivation/reperfusion in PC12 cells through targeting neuronal differentiation 4

SPP1/AnxA1/TIMP1 as Essential Genes Regulate the Inflammatory Response in the Acute Phase of Cerebral Ischemia-Reperfusion in Rats

Background

Ischemic injury in stroke is followed by extensive neurovascular inflammation and changes in ischemic penumbra gene expression patterns. However, the key molecules involved in the inflammatory response during the acute phase of ischemic stroke remain unclear.

Methods

Gene expression profiles of two rat ischemic stroke-related data sets, GSE61616 and GSE97537, were downloaded from the GEO database for Gene Set Enrichment Analysis (GSEA). Then, GEO2R was used to screen differentially expressed genes (DEGs). Furthermore, 170 differentially expressed intersection genes were screened and analyzed for Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Candidate genes and miRNAs were obtained by DAVID, Metascape, Cytoscape, STRING, and TargetScan. Finally, the rat middle cerebral artery occlusion-reperfusion (MCAO/R) model was constructed, and qRT-PCR was used to verify the predicted potential miRNA molecule and its target genes.

Results

GO and KEGG analyses showed that 170 genes were highly associated with inflammatory cell activation and cytokine production. After cluster analysis, seven hub genes highly correlated with post-stroke neuroinflammation were obtained: Cxcl1, Kng1, Il6, AnxA1, TIMP1, SPP1, and Ccl6. The results of TargetScan further suggested that miR-340-5p may negatively regulate SPP1, AnxA1, and TIMP1 simultaneously. In the ischemic penumbra of rats 24 h after MCAO/R, the level of miR-340-5p significantly decreased compared with the control group, while the concentration of SPP1, AnxA1, and TIMP1 increased. Time-course studies demonstrated that the mRNA expression levels of SPP1, AnxA1, and TIMP1 fluctuated dramatically throughout the acute phase of cerebral ischemia-reperfusion (I/R).

Conclusion

Our study suggests that differentially expressed genes SPP1, TIMP1, and ANXA1 may play a vital role in the inflammatory response during the acute phase of cerebral ischemia-reperfusion injury. These genes may be negatively regulated by miR-340-5p. Our results may provide new insights into the complex pathophysiological mechanisms of secondary inflammation after stroke.

Serum Exosomal mir-340-5p Promotes Angiogenesis in Brain Microvascular Endothelial Cells During Oxygen-Glucose Deprivation

Ischemic stroke (IS) is a cerebrovascular disease with high morbidity, recurrence, and mortality. The purpose of the present study was to investigate the role and mechanism of human serum exosomes on angiogenesis after IS. The middle cerebral artery occlusion (MCAO) in vivo model and oxygen-glucose deprivation (OGD) in vitro model were established. Human serum exosomes from healthy samples (NC-exo) and IS samples (IS-exo) were injected into MCAO mice. Neurobehavioral tests were performed to assess the extent of neurological deficits. The infarct volume was assessed by 2,3,5-triphenyl tetrazolium chloride (TTC) staining, and the levels of inflammatory cytokines were analyzed by enzyme-linked immunosorbent assay (ELISA). In addition, human serum exosomes were cocultured with brain microvascular endothelial cells (BMECs). Cell Counting Kit-8 (CCK-8), Transwell, and tubule formation assays were performed to investigate the proliferation, migration, invasion, length, and branching of BMECs. The miRNA expression profiles of NC-exo and IS-exo were analyzed by high-throughput sequencing and compared. Bioinformatics and luciferase reporter assays were performed to evaluate the relationship between miR-340-5p and CD147. Serum NC-exo and IS-exo had protective effects on IS injury and promoted BMEC angiogenesis. Interestingly, the protective effect of IS-exo was weaker than that of NC-exo. In addition, miR-340-5p was downregulated in IS-exo, and miR-340-5p accelerated angiogenesis of BMECs after OGD. Mechanistically, CD147 was confirmed as a direct target of miR-340-5p. Finally, miR-340-5p promoted angiogenesis by directly targeting CD147. Serum exosome-derived miR-340-5p promote angiogenesis in OGD-induced BMECs by targeting CD147.

LncRNA H19 Regulates Lipopolysaccharide (LPS)-Induced Apoptosis and Inflammation of BV2 Microglia Cells Through Targeting miR-325-3p/NEUROD4 Axis

Spinal cord injury (SCI) is a devastating traumatic event worldwide. Work from the past decade has highlighted the key involvement of long non-coding RNAs (lncRNAs) in SCI. Nevertheless, the molecular action of lncRNA H19 in SCI is still not fully understood. The levels of H19, microRNA (miR)-325-3p, and neuronal differentiation 4 (NEUROD4) were determined by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Flow cytometry was performed to assess cell apoptosis. The levels of tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β), and IL-6 were detected using the enzyme-linked immunosorbent assay (ELISA). Targeted relationships among H19, miR-325-3p, and NEUROD4 were confirmed by dual-luciferase reporter, RNA immunoprecipitation (RIP), or RNA pull-down assays. Our data showed that H19 level was overexpressed in lipopolysaccharide (LPS)-treated BV2 cells. H19 silencing alleviated LPS-evoked cell apoptosis and inflammation. Mechanistically, H19 in BV2 cells directly targeted miR-325-3p, and NEUROD4 was a direct target of miR-325-3p. Moreover, miR-325-3p was a functional target of H19 in regulating cell apoptosis and inflammation induced by LPS. Enforced expression of miR-325-3p relieved LPS-evoked cell apoptosis and inflammation through reducing NEUROD4. Furthermore, H19 in BV2 cells regulated NEUROD4 expression through targeting miR-325-3p. Our results identified that the silencing of H19 attenuated LPS-evoked microglia cell apoptosis and inflammation after SCI at least partially through targeting the miR-325-3p/NEUROD4 axis, highlighting a novel approach for SCI management.