Metformin Protects against Oxidative Stress Injury Induced by Ischemia/Reperfusion via Regulation of the lncRNA-H19/miR-148a-3p/Rock2 Axis

Abstract

Previous studies have shown that metformin not only is a hypoglycemic agent but also has neuroprotective effects. However, the mechanism of action of metformin in ischemic stroke is unclear. Oxidative stress is an important factor in the pathogenesis of cerebral ischemia-reperfusion injury. It has been reported that metformin is associated with stroke risk in the clinical population. This study is aimed at investigating the effect and mechanism of metformin in an experimental model of oxidative stress induced by ischemia/reperfusion (I/R) in vivo and oxygen glucose deprivation/reperfusion (OGD/R) in vitro. Metformin (100, 200, and 300 mg/kg) was administered intraperitoneally immediately after induction of cerebral ischemia. The indicators of oxidative stress selected were antioxidant enzyme activities of catalase, malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), and glutathione peroxidation enzyme (GSHPx). First, we demonstrated that metformin can significantly alleviate acute and chronic cerebral I/R injury and it has a strong regulatory effect on stroke-induced oxidative stress. It can reduce the elevated activities of MDA and NO and increase the levels of GSHPx and SOD in the cerebrum of mice and N2a cells exposed to I/R. Furthermore, real-time PCR and western blot were used to detect the expression of long noncoding RNA H19 (lncRNA-H19), microRNA-148a-3p (miR-148a-3p), and Rho-associated protein kinase 2 (Rock2). The direct interaction of lncRNA-H19, miR-148a-3p, and Rock2 was tested using a dual luciferase reporter assay. lncRNA-H19 altered OGD/R-induced oxidative stress by modulating miR-148a-3p to increase Rock2 expression. The expression of lncRNA-H19 and Rock2 could be downregulated with metformin in vivo and in vitro. In conclusion, our study confirmed that metformin exerts neuroprotective effects by regulating ischemic stroke-induced oxidative stress injury via the lncRNA-H19/miR-148a-3p/Rock2 axis. These results provide new evidence that metformin may represent a potential treatment for stroke-related brain injury.

Comparison of Effects of Metformin, Phenformin, and Inhibitors of Mitochondrial Complex I on Mitochondrial Permeability Transition and Ischemic Brain Injury

“…Hypoxia-induced necrosis in slice cultures from adult brains was found to be prevented by pre-treatment with both phenformin and metformin. These findings are in agreement with previously reported studies by other investigators: Zeng and colleges performed study in vivo with 2–3 month old mice and showed that metformin administered intraperitoneally immediately after induction of cerebral ischemia increased neuronal survival [ 46 ]. In another study with 2–3 month old rats administration of metformin by 1, 3, or 7 days before stroke resulted in the reduction of cerebral infarction volume [ 47 ].…”

“…These data correlate with findings by other researchers showing that 5–7 days old rats brain slice cultures were more sensitive to decreased glucose than slices from 2–3 months and older rats [ 43 ]. The exact mechanism of how DOG reduces hypoxia-induced cell death in adult rat brains is not clear, but inhibition of glycolysis by DOG may involve activation of some pro-survival signaling pathways, like hypoxia-inducible factor-1α [ 44 ], signal transducer and activator of transcription 3 and transcription factor 4 [ 45 , 46 ].…”

MicroRNA expression profiling after recurrent febrile seizures in rat and emerging role of miR-148a-3p/SYNJ1 axis

“…Studies have shown that the function of differentially expressed miR-148a-3p is closely related to neuroimmunity and apoptosis. Recent studies have shown that in ischemic stroke-related diseases, miR-148a-3p can interact with lncRNA-h19 and ROCK2 genes to form a pathway that regulates the oxidative stress caused by ischemic stroke 18 . Additionally, miR-148a-3p can target the KLF6 gene to regulate the proliferation and apoptosis of skeletal muscle cells 14 , 15 .…”

“…New evidence has shown that miR-148-a may regulate the MAPK pathway during oxygen and glucose deprivation-induced microglial inflammation, which is of vital importance in ischemic injury induced by hypoxia. Recent studies have suggested that miR-148a-3p may play an important role in nervous and immune systems 18 – 21 . Compared with the diverse mechanisms for miR-148a-3p functions in cancer or other diseases, how miR-148a-3p regulates specific neuroimmune diseases is poorly understood.…”

Long Noncoding RNA/Circular RNA-miRNA-mRNA Axes in Ischemia-Reperfusion Injury

“…The H19/miR-19a/Id2 axis regulates hypoxia-induced neuronal apoptosis, and inhibition of this axis may serve as a novel therapeutic strategy for ischemic brain injury [ 98 ]. Previous reports have established a role and mechanism of metformin in shock-related brain injury [ 99 ]. Zeng et al [ 99 ] found that H19 modified oxidative stress under OGD/R by binding to miR-148a-3p to upregulate Rock2 (Rho-associated protein kinase 2) expression, which was reversed by metformin.…”