ABSTRACT
Circular RNAs (circRNAs),a kind of novel non-coding RNAs, have been shown to play animportant role in cellular redox reactions. In the previous study, we found that hsa_circ_0087354 wasclosely related to the cellular redox state by real-time PCR. After overexpression of hsa_circ_0087354, the relative expression of ROS1 were decreased significantly (P < 0. 01), while the levels of SOD1 wereincreased significantly (P < 0. 05) . The activities of SOD and Gpx as well as GSH concentration weresignificantly increased (P < 0. 01), and cell proliferation was promoted in cells (P < 0. 05) . Bioinformatics analysis predicted that there were binding sites between hsa-miR-199-3p and hsa_circ_0087354 as well as solute carrier family 7 member 11 (SLC7A11), which might have a targetedregulatory relationship. Dual luciferase reporter assay confirmed the targeted regulatory relationshipbetween hsa-miR-199-3p with hsa_circ_0087354, and SLC7A11. Overexpressed hsa_circ_0087354 plasmid and ctrl plasmid were constructed, hsa-miR-199a-3p, hsa-miR-199b-3p and hsa-miR-NC mimicswere synthesized. Real-time PCR analysis showed that the relative expression of hsa-miR-199-3p was observably decreased (P < 0.01), while the relative expression of SLC7A11 in cells was dramaticallyincreased after transfection of has_circ_0087354 plasmid (P < 0.05) . After transfection with hsa-miR-199-3p, the relative expressions of SLC7A11 were markedly decreased (P < 0.001) . The activities ofSOD and Gpx, GSH concentration (P<0.01), and cell proliferation rate (P < 0.05) were significantlyreduced. In conclusion, hsa_circ_0087354 could enhance the expression of SLC7A11, promote theproliferation of cells and reduce the oxidative stress by adsorption of hsa-miR-199-3p.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the protein levels of phospho-ERK and phospho-APE/Ref-1 in hippocampal neurons after global cerebral ischemia reperfusion in rats, and observe the relationship between transmembrane signal transduction and repair of DNA damage. The role of ERK signal transduction pathway following global cerebral ischemia reperfusion in rats is further discussed.</p><p><b>METHODS</b>Ninety healthy male SD rats were divided into 3 groups randomly: Sham group (S group), Ischemia reperfusion group (IR group) and Pd98059 pretreatment/ischemia reperfusion group (PD group). Global cerebral ischemia reperfusion model was established by four-vessel occlusion (4-VO) method, and reperfusion was performed 5 minutes following ischemia. Protein levels of phospho-ERK and phospho-APE/Ref-1 were detected using immunohistochemical method at 2 h, 6 h, 12 h, 24 h, 48 h and 72 h after reperfusion, and neuron apoptosis was observed by HE and TUNEL staining.</p><p><b>RESULTS</b>In CA1 region of IR group, TUNEL positive cells began to appear at 6 h after IR, and reached the apex during 24 h to 48 h. However, TUNEL positive was most strongly exhibited in PD group. In IR group, phospho-ERK was obviously detected in CA3 region at 2 h after IR, and its level was gradually decreased from 6 h until totally absent at 48 h. Besides, phospho-ERK expression in PD group was weaker than that in IR group. For phospho-APE/Ref-1, its expression began to appear in CA1 region in IR group at 2 h after IR, with no obvious changes during 2 h to 12 h. Phospho-APE/Ref-1 expression began to decrease at 24 h and this decrease continued thereafter. Expression level of phospho-APE/Ref-1 in PD group was lower than that in IR group. Results showed the concurrence of decreased phospho-ERK expression level and increased neuron apoptosis after cerebral ischemia reperfusion, the former of which was consistent with the decrease of phospho-APE/Ref-1 expression. Also, the greater the inhibition of ERK phosphorylation was, the greater decrease of APE/Ref-1 expression occurred.</p><p><b>CONCLUSION</b>Activation of ERK signal transduction pathway increased the expression of phospho-APE/Ref-1, and thus faciliated the repair of DNA damage. So, activation of ERK signal transduction pathway may protect neurons from apoptosis after cerebral ischemia reperfusion.</p>