MicroRNA-181c Exacerbates Brain Injury in Acute Ischemic Stroke

Abstract

MicroRNA-181 (miR-181) is highly expressed in the brain, and downregulated in miRNA expression profiles of acute ischemic stroke patients. However, the roles of miR-181c in stroke are not known. The clinical relevance of miR-181c in acute stroke patients was evaluated by real-time PCR and correlation analyses. Proliferation and apoptosis of BV2 microglial cells and Neuro-2a cells cultured separately or together under oxidative stress or inflammation were assessed with the Cell Counting Kit-8 and by flow cytometry, respectively. Cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in C57/BL6 mice, and cerebral infarct volume, microglia activation, and expression of pro-apoptotic factors were evaluated by 2,3,5-triphenyl-2H-tetrazolium chloride staining, immunocytochemistry, and western blotting, respectively. Plasma levels of miR-181c were decreased in stroke patients relative to healthy individuals, and were positively correlated with neutrophil number and blood platelet count and negatively correlated with lymphocyte number. Lipopolysaccharide (LPS)/hydrogen peroxide (H2O2) treatment inhibited BV2 microglia proliferation without inducing apoptosis, while miR-181c reduced proliferation but increased the apoptosis of these cells with or without LPS/H2O2 treatment. LPS/H2O2 induced apoptosis in Neuro-2a cells co-cultured with BV2 cells, an effect that was potentiated by miR-181c. In the MCAO model, miR-181c agomir modestly increased infarct volume, markedly decreased microglia activation and B cell lymphoma-2 expression, and increased the levels of pro-apoptotic proteins in the ischemic brain. Our data indicate that miR-181c contributes to brain injury in acute ischemic stroke by promoting apoptosis of microglia and neurons via modulation of pro- and anti-apoptotic proteins.

Melatonin protects against ischemic stroke by modulating microglia/macrophage polarization toward anti‐inflammatory phenotype through STAT3 pathway

“…BV2 (microglia cell line) and N2a (neuron cell line) were purchased from Cell Center, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences (CAMS), and Peking Union Medical College (PUMC). Both of them were cultured in the Dulbecco's Modified Eagle's Medium supplemented (Gibco) with 10% fetal bovine serum (Gibco) and 1% penicillin‐streptomycin (Gibco) at 37°C in CO 2 /air (5% /95%) mixture . We used OGD neuron‐conditioned medium (CM) to stimulate resting microglia.…”

Bone marrow–derived mesenchymal stem cells–derived exosomes prevent oligodendrocyte apoptosis through exosomal miR‐134 by targeting caspase‐8

“…They are a class of short (about 22 nucleotides), single‐strand noncoding RNAs that have key roles in the regulation of gene expression. MiRNAs can either promote or inhibit oligodendrocytes (OLs) apoptosis, and also regulate acute cerebral ischemic‐mediated stroke . However, whether miRNAs from bone marrow–derived mesenchymal stem cells (BMSCs)‐derived exosomes have some important roles in cerebral hypoxia or ischemic‐induced OLs remains yet to be elucidated.…”

MicroRNA‐365 modulates astrocyte conversion into neuron in adult rat brain after stroke by targeting Pax6

“…Astrocytes were identified with glial fibrillary acidic protein (GFAP) immunolabeling and were used for experiments when the number of GFAP‐positive cells exceeded 95% of the total. Cultured astrocytes were transfected with 50 nM agomir or antagomir or negative‐control (GenePharma; Ma et al, ) using lipofectamine 2000 (Invitrogen, Rockville, MD, USA) according to the manufacturer's protocol. The cells were harvested at 48 hr after transfection for further detection of miRs, mRNAs and proteins.…”

“…The injection rate was 0.19 μl/min, and the glass pipette was left in the place for an additional 15 min before being withdrawn at a rate of 1 mm/min. The miR agomir, antagomir and negative controls were diluted to a final concentration of 100 μM for intracerebroventricular infusion (Ge et al, ; Ma et al, ; Tao et al, ). MiR oligomers (5 μl) were then combined with lipofectamine 2000 (5 μl) in an RNase‐free PCR tube and incubated for at least 20 min at room temperature.…”