The decreased circular RNA hsa_circ_0072309 promotes cell apoptosis of ischemic stroke by sponging miR-100.

OBJECTIVE: To investigate the expression of circ_0072309 in patients with ischemic stroke (IS) and in LIFR humanized mice with middle cerebral artery occlusion (MCAO). Further, we explored the underlying mechanism of circ-0072309 in IS. MATERIALS AND METHODS: The content of circ-0072309 in serum of patients with IS (n = 70) was measured by qRT-PCR, and the ROC curve was analyzed. LIFR humanized mice were used to measure the content of circ-0072309 in ischemic hemisphere by qRT-PCR and the protein expression of cleaved-caspase-3, cleavedcaspase- 8 were detected by Western blot. After that, the expression of miR-100 in serum of patients with IS and in ischemic hemisphere of MCAO mice were detected, and then, we analyzed the correlation between the expression of circ-0072309 and miR-100. The binding sites between circ-0072309 and miR-100 were predicted by online database. We detected whether cric-0072309 bind to miR-100 by Dual-Luciferase report in bEnd2. In addition, bEnd2 was treated with oxygen-glucose deprivation (OGD) to simulate injury of cerebral vascular after cerebral ischemia. After treated with miR-100 mimic or miR-100-inhibitor, we detected the cell survival and rate of cell apoptosis, and the content of cleaved-caspase-3 and caspase-8 protein. The target mRNA of miR-100 was predicted by bioinformatics analysis and analyzed by Dual-Luciferase. After treating bEnd2 with circ-0072309 and miR-100 mimic, we analyzed the cell survival and apoptosis to identify the potential regulatory mechanism. RESULTS: The results of qRT-PCR showed that the expression of circ-0072309 was significantly decreased while the content of miR- 100 was significantly increased in the serum of IS patients and in the ischemic hemisphere of MCAO mice. There was a negative correlation between the expression of circ-0072309 and miR- 100. The results of Dual-Luciferase showed that circ-0072309 could directly bind to miR-100. After treating bEnd2 with OGD, miR-100-mimic caused a decrease rate of cell survival and an increased rate of apoptosis. Dual-Luciferase showed that miR-100 regulated cell survival and apoptosis by directly binding to mTOR. By comparing treated bEnd2 with circ-0072309, co-transfected bEnd2 with circ-0072309 and miR-100 reduced cell survival and increased apoptosis. CONCLUSIONS: According to these results, this study revealed that the circ_0072309-miR- 100-mTOR regulatory axis could alleviate IS, and it may be a potential target for the treatment of IS. [ABSTRACT FROM AUTHOR]