Inhibition of MiRNA-125b Decreases Cerebral Ischemia/Reperfusion Injury by Targeting CK2α/NADPH Oxidase Signaling

Abstract

Background/Aims: Cerebral ischemia-reperfusion (I/R) injury involves multiple independently fatal terminal pathways. CK2α/NADPH oxidase is an important signaling pathway associated with ischemia-reperfusion injury, and miR-125b can regulate oxidative stress-related injury. In this study, we investigated whether the effect of miR-125b in rat brain I/R injury occurs through its modulation of the CK2α/NADPH oxidase pathway. Methods: Rats were subjected to 2 h of cerebral ischemia followed by 24 h of reperfusion to establish an I/R injury model. Neurological deficit was evaluated using a five-point score. Infarct volume was evaluated with 2, 3, 5-triphenyltetrazolium chloride (TTC) staining, and RT-PCR was used to detect expressions of miR125b and CK2α. We then examined the association between miR-125b expression and the CK2α/NADPH oxidative signaling pathway in a PC-12 cell oxygen-glucose deprivation and reoxygenation (OGD/R) injury model. Transfection with miR-125b mimics, an miR-125b inhibitor, and luciferase reporter gene plasmid was accomplished using commercial kits. In these cells, Western blots were used to detect the levels of expression of CK2α, cleaved caspase-3, NOX2, and NOX4. RT-PCR was used to detect the expressions of CK2α, miR125b, NOX2, and NOX4. We evaluated Lactate Dehydrogenase (LDH) level, NADPH oxidase activity, and caspase-3 activity using commercial kits. Mitochondrial reactive oxygen species (ROS) were measured by fluorescence microscopy. For both PC-12 cells and rat brains, histological analyses were conducted to observe morphological changes, and apoptosis was measured using a commercial kit. Results: I/R rats exhibited an increase in neurological deficit score, infarct volume, and cellular apoptosis, along with miR-125b elevation and CK2α downregulation. OGD/R treatment increased PC-12 cells’ injuries, cellular apoptosis, and ROS levels. These changes were associated with miR-125b elevation, CK2α downregulation and activations of NOX2 and NOX4, mimicking our in vivo findings. All of these effects were reversed by the inhibition of miR-125b, confirming a strong correlation between miR-125b activity and the CK2α/NADPH oxidase signaling pathway. Conclusions: Based on these observations, we conclude that inhibition of miR-125b protects the rat brain from I/R injury by regulating the CK2α/NADPH oxidative signaling pathway.

Theaflavin attenuates cerebral ischemia/reperfusion injury by abolishing miRNA‑128‑3p‑mediated Nrf2 inhibition and reducing oxidative stress

“…The miRNAs are crucial regulators in spontaneous neurogenesis and sustainability of neuronal phenotype by post-transcriptional regulation. Furthermore, miRNAs, including miRNA-23a-3p, miRNA-424, and miRNA-125b reportedly reduce CI/RI by targeting the oxidative stress pathway (37–39). Based on these functions of miRNA, Nrf2 mRNA/miRNA interaction was predicted using the miRNA target prediction tool, TargetScan, and Nrf2 mRNA/miRNA-128-3p interaction information was also predicted.…”

Icariside II, a PDE5 Inhibitor, Suppresses Oxygen-Glucose Deprivation/Reperfusion-Induced Primary Hippocampal Neuronal Death Through Activating the PKG/CREB/BDNF/TrkB Signaling Pathway

“…Since ischemic stroke is mostly caused by extracranial embolism or intracranial thrombosis, up to now, thrombolytic therapy is the most robust therapy for ischemic stroke (Saenger and Christenson, 2010). However, cerebral ischemic/reperfusion (I/R) injury caused by restoring blood flow after thrombolytic therapy aggravates neuronal apoptosis and exacerbates neuronal death (Liang et al, 2018). Most importantly, cerebral I/R injury further exacerbates cognitive impairment that is related with neurons apoptosis in hippocampus (Xu et al, 2019), which are more susceptible to cerebral I/R injury than the ones in other brain regions.…”

miR-378a-5p regulates CAMKK2/AMPK pathway to contribute to cerebral ischemia/reperfusion injury-induced neuronal apoptosis

“…Sustained OGD (lasting more than 1 hour) followed by re-oxygenation (OGDR) has been proved to induce mitochondria dysfunction, ROS production, and cell necrosis [18]. In this study, the expression of miR-378a-5p was significantly increased after OGDR in primary rat (CK2α)/NADPH oxidase signaling pathway [19]. miR-182-5p, which was downregulated after OGD in microglial cells, could prevent CIR injury by direct binding to Toll-like receptor 4, demonstrating a neuroprotective effect [20].…”