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MiR-424 Inhibits neuronal apoptosis in rats with cerebral infarction through regulating TGF-β1/Smad3 signaling
1Department of Neurology, Affiliated Hospital of Jiangnan University/The Third People's Hospital of Wuxi, Wuxi, China.
Abstract:
It has been reported that micro ribonucleic acid (miR)-424 is an important molecule in cerebral ischemia. However, the precise mechanism of action and biological effects of miR-424 remain to be further explored. miR-424 mimic and miR-424 inhibitor were injected via the caudal vein in rats, and the effect of miR-424 expression on brain tissue damage induced by middle cerebral artery occlusion (MCAO) was detected. The miR-424 mimic-induced changes in genomic levels were detected via the gene chip assay, and the signaling pathways regulated by miR-424 and its potential targets were explored combined with target prediction. Then the effect of miR-424 mimic on apoptosis of PC12 cells induced by oxygen-glucose deprivation (OGD) was determined using Annexin V/PI assay. Finally, drosophila mothers against decapentaplegic protein 7 (Smad7) was overexpressed to further verify the mechanism of action of miR-424 mimic. Compared with that in the sham group, the expression of miR-424 in brain tissues significantly declined in the model group. The results of 2,3,5-triphenyltetrazolium chloride (TTC) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay revealed that the miR-424 mimic obviously reduced the cerebral infarction area and apoptosis level of brain tissues, while the miR-424 inhibitor obviously increased the cerebral infarction area and apoptosis level of brain tissues. It was found, using bioinformatics and KEGG enrichment analysis, that differentially expressed genes induced by miR-424 were significantly enriched in the transforming growth factor-β (TGF-β) signaling pathway. According to the results of reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting, the miR-424 mimic could evidently lower the expression of Smad7, thus activating the TGF-β1/Smad3 signaling pathway. Overexpression of Smad7 could weaken the protective effect of miR-424 mimic on ischemic-hypoxic cells. Increasing the expression of miR-424 can inhibit Smad7 to activate the TGF-β1/Smad3 signaling pathway, thereby exerting a protective effect against the brain tissue damage induced by MCAO.
Insights
Micro ribonucleic acid (miR)-424 protects brain tissue from damage after middle cerebral artery occlusion by inhibiting Smad7 and activating the TGF-β1/Smad3 pathway. This finding offers a potential therapeutic target for cerebral ischemia.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- Micro ribonucleic acid (miR)-424 is implicated in cerebral ischemia, but its precise mechanism and effects require further elucidation.
- Cerebral ischemia, a condition caused by interrupted blood supply to the brain, leads to significant tissue damage and apoptosis.
- Understanding the molecular pathways involved in cerebral ischemia is crucial for developing effective therapeutic strategies.
Purpose of the Study:
- To investigate the role and mechanism of miR-424 in brain tissue damage induced by middle cerebral artery occlusion (MCAO).
- To explore the signaling pathways regulated by miR-424 and identify its potential targets.
- To determine the therapeutic potential of modulating miR-424 expression in cerebral ischemia.
Main Methods:
- In vivo studies involving miR-424 mimic and inhibitor administration in MCAO rat models.
- Gene chip assay for analyzing genomic changes induced by miR-424 mimic.
- Bioinformatics and KEGG enrichment analysis to identify regulated signaling pathways.
- In vitro studies using PC12 cells subjected to oxygen-glucose deprivation (OGD) to assess apoptosis.
- Overexpression of drosophila mothers against decapentaplegic protein 7 (Smad7) to validate the mechanism.
Main Results:
- miR-424 expression was significantly decreased in MCAO-induced brain tissues.
- miR-424 mimic reduced cerebral infarction area and apoptosis, while miR-424 inhibitor increased them.
- Bioinformatics analysis revealed enrichment of differentially expressed genes in the transforming growth factor-β (TGF-β) signaling pathway.
- miR-424 mimic decreased Smad7 expression, activating the TGF-β1/Smad3 signaling pathway.
- Overexpression of Smad7 attenuated the protective effect of miR-424 mimic on ischemic-hypoxic cells.
Conclusions:
- miR-424 exerts a protective effect against MCAO-induced brain tissue damage.
- The protective mechanism involves the inhibition of Smad7 and subsequent activation of the TGF-β1/Smad3 signaling pathway.
- Modulating miR-424 expression represents a potential therapeutic strategy for cerebral ischemia.
