Panax quinquefolium saponins attenuates microglia activation following acute cerebral ischemia-reperfusion injury via Nrf2/miR-103-3p/TANK pathway

Ischemic stroke is one of the leading causes of death and disability among adults worldwide. Intravenous thrombolysis is the only approved pharmacological treatment for acute ischemic stroke. However, reperfusion by thrombolysis will lead to the rapid activation of microglia cells which induces interferon-inflammatory response in the ischemic brain tissues. Panax quinquefolium saponins (PQS) has been proven to be effective in acute ischemic stroke, but there is no unified understanding about its specific mechanism. Here, we will report for the first time that PQS can significantly inhibit the activation of microglia cells in cerebral of MCAO rats via activation of Nrf2/miR-103-3p/TANK axis. Our results showed that PQS can directly bind to Nrf2 protein and inhibit its ubiquitination, which result in the indirectly enhancing the expression of TANK protein via transcriptional regulation on miR-103-3p, and finally to suppress the nuclear factor kappa-B dominated rapid activation of microglial cells induced by oxygen-glucose deprivation/reoxygenation  vitro and cerebral ischemia-reperfusion injury in vivo. In conclusion, our study not only revealed the new mechanism of PQS in protecting against the inflammatory activation of microglia cells caused by cerebral ischemia-reperfusion injury, but also suggested that Nrf2 is a potential target for development of new drugs of ischemic stroke. More importantly, our study also reminded that miR-103-3p might be used as a prognostic biomarker for patients with ischemic stroke.

Exosomal miR-133a-3p Derived from BMSCs Alleviates Cerebral Ischemia-Reperfusion Injury via Targeting DAPK2

Background

Cerebral ischemia-reperfusion (CI/R) injury is a subtype of complication after treatment of ischemic stroke. It has been reported that exosomes derived from BMSCs could play an important role in CI/R injury. However, whether BMSCs-derived exosomes could regulate CI/R injury via carrying miRNAs remains to be further explored.

Methods

RNA sequencing was performed to identify the differentially expressed miRNAs. To mimic CI/R in vitro, SH-SY5Y cells were exposed to oxygen glucose deprivation/reoxygenation (OGD/R). The viability of SH-SY5Y cells was tested by CCK8 assay, and TUNEL staining was performed to detect the cell apoptosis.

Results

MiR-133a-3p was identified to be reduced in exosomes derived from the plasma of patients with IS. Upregulation of miR-133a-3p significantly reversed OGD/R-induced SH-SY5Y cell growth inhibition. Consistently, BMSCs-derived exosomal miR-133a-3p could restore OGD/R-decreased SH-SY5Y cell proliferation via inhibiting apoptosis. Meanwhile, DAPK2 was a direct target of miR-133a-3p. In addition, OGD/R notably upregulated the level of DAPK2 and weakened the expressions of p-Akt and p-mTOR in SH-SY5Y cells, whereas exosomal miR-133a-3p derived from BMSCs notably reversed these phenomena. Exosomal miR-133a-3p derived from BMSCs could reverse OGD/R-induced cell apoptosis via inhibiting autophagy. Furthermore, exosomal miR-133a-3p derived from BMSCs markedly alleviated the symptom of CI/R injury in vivo.

Conclusion

Exosomal miR-133a-3p derived from BMSCs alleviates CI/R injury via targeting DAPK2/Akt signaling. Thus, our study might shed new light on discovering new strategies against CI/R injury.

Interfering TUG1 Attenuates Cerebrovascular Endothelial Apoptosis and Inflammatory injury After Cerebral Ischemia/Reperfusion via TUG1/miR-410/FOXO3 ceRNA Axis

Background Emerging studies illustrate that long non-coding RNA TUG1 (TUG1) participates in neuron death after ischemia. However, the role of TUG1 in cerebral ischemia/reperfusion (CI/R) injury through cerebrovascular pathology was undetermined yet. Methods Expression of TUG1, miRNA-410-3p (miR-410), and forkhead box O3 (FOXO3) was detected by RT-qPCR and western blot. Neural function, apoptosis, and inflammatory damage were assessed by triphenyltetrazolium chloride straining, modified neurological severity score, fluorescence-activated cell sorting method, and western blot. The relationship among TUG1, miR-410, and FOXO3 was identified by dual-luciferase reporter assay, RNA pull-down, and RNA immunoprecipitation. Results TUG1 was upregulated in middle cerebral artery occlusion/reperfusion (MCAO/R) mice and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced mouse brain microvascular endothelial cells (BMECs) in a certain of time-dependent manner. Blockage of TUG1 decreased infarct volume and increased neurological score in MCAO/R mice, accompanied with elevated Bcl-2 expression and declined expression of IL-1β, IL-6, TNF-α, Bax, and cleaved caspase 3. Abovementioned proteins were similarly expressed in OGD/R-induced BMECs with TUG1 knockdown, paralleled with diminished apoptosis rate. Either, miR-410 overexpression and FOXO3 interference could suppress OGD/R-induced inflammatory and apoptotic responses. Of note, TUG1 and FOXO3 are competing endogenous RNAs (ceRNAs) for miR-410 via target binding. Depleting miR-410 counteracted the role of TUG1 exhaustion, and reinforcing FOXO3 abated the effect of miR-410 overexpression. Conclusion Exhausting TUG1 could alleviate CI/R-induced inflammatory injury and apoptosis in brain tissues and BMECs via targeting miR-410/FOXO3 axis, suggesting an innovative perspective from cerebrovascular endothelial cells in the pathogenesis and treatment of CI/R.

MiR-27a-3p suppresses cerebral ischemia-reperfusion injury by targeting FOXO1

Cerebral ischemia-reperfusion (CI/R) injury is a serious complication when treating patients experiencing ischemic stroke. Although the microRNA miR-27a-3p reportedly participates in ischemia/reperfusion (I/R) injury, its actions in CI/R remain unclear. To mimic CI/R in vitro, HT22 cells were subjected to oxygen glucose deprivation/reoxygenation (OGD/R). The results indicate that OGD inhibited growth and induced apoptosis among HT22 cells. The apoptosis was accompanied by increases in activated caspases 3 and 9 and decreases in Bcl-2. Oxidative stress was also increased, as indicated by increases in ROS and malondialdehyde and decreases in glutathione and superoxide dismutase. In addition, OGD induced G1 arrest in HT22 cells with corresponding upregulation of FOXO1 and p27 Kip1, suggesting the cell cycle arrest was mediated by FOXO1/p27 Kip1 signaling. Notably, FOXO1 was found to be the direct target of miR-27a-3p in HT22 cells. MiR-27a-3p was downregulated in OGD/R-treated HT22 cells, and miR-27a-3p mimics partially or entirely reversed all of the in vitro effects of OGD. Moreover, miR-27a-3p agomir significantly alleviated the symptoms of CI/R in vivo in a rat model of CI/R. Thus, MiR-27a-3p appears to suppress CI/R injury by targeting FOXO1.