Silencing of circCDC14A prevents cerebral ischemia-reperfusion injury via miR-23a-3p/CXCL12 axis

Ischemic stroke is one of the main causes of death and disability. Circular RNAs (circRNAs) have received extensive attention in the pathogenesis of ischemic stroke. Here, we evaluated the role of circCDC14A in cerebral ischemia-reperfusion (CI/R) injury in vivo and in vitro. The expression of circCDC14A was significantly upregulated in the middle cerebral artery occlusion (MCAO) model and oxygen and glucose deprivation/reoxygenation (OGD/R)-treated HT22 cells. Knockdown of circCDC14A suppressed the cell viability reduction caused by OGD/R, as well as cell damage and apoptosis. Mechanistically, circCDC14A acted as a sponge for miR-23a-3p and promoted the expression of chemokine stromal-derived factor-1 (CXCL12) by negatively regulating miR-23a-3p. Rescue experiments further confirmed that miR-23a-3p inhibitor or circCDC14A-overexpression vectors blocked the beneficial effects of circCDC14A knockdown in OGD/R-induced HT22 cells. Moreover, knockdown of circCDC14A suppressed MCAO-induced cerebral infarction and neurological damage, as well as the brain tissue damage and neuronal apoptosis in vivo. Consistently, miR-23a-3p antagomir treatment abolished the cerebral protective effects of circCDC14A knockdown on MCAO mice. In conclusion, circCDC14A promoted CI/R injury by regulating the miR-23a-3p/CXCL12 axis, which suggested that circCDC14A may become a potential therapeutic target for CI/R injury.

Long non-coding RNA TUG1 aggravates cerebral ischemia and reperfusion injury by sponging miR-493-3p/miR-410-3p

Background

Cerebral ischemia and reperfusion injury (CIRI) affects bodily function by causing irreversible damage to brain cells. The diverse pathophysiological course factors hinder the research work to go deeper. Long noncoding RNA taurine-upregulated gene 1 (TUG1) has been reported to be related to CIRI. This study explored the undefined regulatory pathway of TUG1 in CIRI.

Methods

Quantitative real-time polymerase chain reaction was applied to test the expression of TUG1, microRNA (miR)-493-3p and miR-410-3p. The viability and apoptosis of oxygen and glucose deprivation/reoxygen (OGD/R) model cells were evaluated by cell counting kit-8 and flow cytometry assay, respectively. The determination of inflammatory factors of interleukin-6, interleukin-1β and tumor necrosis factor-α was presented by enzyme-linked immunosorbent assay. The oxidative stress was performed by measuring the generation of malondialdehyde, reactive oxygen species and the activity of superoxide dismutase. Cytotoxicity was presented by measuring the generation of lactate dehydrogenase. Western blot assay was devoted to assessing the level of apoptosis-related factors (cleaved-caspase-3 and cleaved-caspase-9) and the protein level of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38 MAPK) pathway-related factors in neuro-2a cells treated by OGD/R. Besides, online database starBase was applied to predict the potential binding sites of TUG1 to miR-493-3p and miR-410-3p, which was further confirmed by the dual-luciferase reporter system.

Results

The expression of TUG1 was upregulated, while miR-493-3p or miR-410-3p was downregulated in the serum of CIRI and OGD/R model cells. Meanwhile, knockdown of TUG1 eliminated the suppression in proliferation, the promotion in apoptosis, inflammation and oxidative stress, as well as the cytotoxicity in OGD/R model cells. Interestingly, the inhibition of miR-493-3p or miR-410-3p allayed the above effects. In addition, TUG1 harbored miR-493-3p or miR-410-3p and negatively regulated their expression. Finally, the TUG1 activated JNK and p38 MAPK pathways by sponging miR-493-3p/miR-410-3p.

Conclusion

TUG1 motivated the development of CIRI by sponging miR-493-3p/miR-410-3p to activate JNK and p38 pathways. The novel role of TUG1 in CIRI may contribute to the advancement of CIRI treatment.