MicroRNA-322-5p protects against myocardial infarction through targeting BTG2

LncRNA ZFAS1/miR-186-5p axis is involved in oxidative stress inhibition of myocardial ischemia-reperfusion injury by targeting BTG2

OBJECTIVE

To probe the involvement of long noncoding RNA zinc finger antisense 1 (ZFAS1)/microRNA (miR)-186-5p axis in inhibiting oxidative stress in myocardial ischemia-reperfusion injury (MIRI) by targeting B-cell translocation gene 2 (BTG2).

METHODS

The MIRI mice model was established by ligating the left anterior descending branch of the left coronary artery in C57BL/6 mice. The in vitro MIRI model was constructed by hypoxia and reoxygenation of HL-1 cardiomyocytes. Cardiomyocyte apoptosis and the extent of myocardial injury in mice were detected. The apoptosis rates, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in HL-1 cells were assessed. The relationship among ZFAS1, miR-186-5p, and BTG2 was verified.

RESULTS

High ZFAS1 and BTG2 levels and low miR-186-5p levels were demonstrated in I/R-injured myocardial tissues and in H/R-treated cardiomyocytes. Interference with ZFAS1 or elevation of miR-186-5p inhibited apoptosis and oxidative stress in H/R model cardiomyocytes and I/R-injured myocardial tissues. Overexpressing BTG2 impaired the ameliorative effects of miR-186-5p on MIRI. ZFAS1 negatively regulated miR-186-5p expression by acting as a molecular sponge. miR-186-5p targeted to regulate BTG2 negatively.

CONCLUSION

Interfering with ZFAS1 can upregulate miR-186-5p and thus inhibit BTG2 expression, thereby ameliorating MIRI.

Innovative Therapeutic Strategies for Myocardial Infarction Across Various Stages: Non-Coding RNA and Stem Cells

Myocardial infarction (MI) is a highly challenging and fatal disease, with diverse challenges arising at different stages of its progression. As such, non-coding RNAs (ncRNAs), which can broadly regulate cell fate, and stem cells with multi-differentiation potential are emerging as novel therapeutic approaches for treating MI across its various stages. NcRNAs, including microRNAs (miRNAs) and long non-coding RNAs (LncRNAs), can directly participate in regulating intracellular signaling pathways, influence cardiac angiogenesis, and promote the repair of infarcted myocardium. Currently, stem cells commonly used in medicine, such as mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPSCs), can differentiate into various human cell types without ethical concerns. When combined with ncRNAs, these stem cells can more effectively induce directed differentiation, promote angiogenesis in the infarcted heart, and replenish normal cardiac cells. Additionally, stem cell-derived exosomes, which contain various ncRNAs, can improve myocardial damage in the infarcted region through paracrine mechanisms. However, our understanding of the specific roles and mechanisms of ncRNAs, stem cells, and exosomes secreted by stem cells during different stages of MI remains limited. Therefore, this review systematically categorizes the different stages of MI, aiming to summarize the direct regulatory effects of ncRNAs on an infarcted myocardium at different points of disease progression. Moreover, it explores the specific roles and mechanisms of stem cell therapy and exosome therapy in this complex pathological evolution process. The objective of this review was to provide novel insights into therapeutic strategies for different stages of MI and open new research directions for the application of stem cells and ncRNAs in the field of MI repair.

MicroRNA-322-5p targeting Smurf2 regulates the TGF-β/Smad pathway to protect cardiac function and inhibit myocardial infarction

Acute coronary artery blockage leads to acute myocardial infarction (AMI). Cardiomyocytes are terminally differentiated cells that rarely divide. Treatments preventing cardiomyocyte loss during AMI have a high therapeutic benefit. Accumulating evidence shows that microRNAs (miRNAs) may play an essential role in cardiovascular diseases. This study aims to explore the biological function and underlying regulatory molecular mechanism of miR-322-5p on myocardial infarction (MI). This study's miR-322-5p is downregulated in MI-injured hearts according to integrative bioinformatics and experimental analyses. In the MI rat model, miR-322-5p overexpression partially eliminated MI-induced changes in myocardial enzymes and oxidative stress markers, improved MI-caused impairment on cardiac functions, inhibited myocardial apoptosis, attenuated MI-caused alterations in TGF-β, p-Smad2, p-Smad4, and Smad7 protein levels. In oxygen-glucose deprivation (OGD)-injured H9c2 cells, miR-322-5p overexpression partially rescued OGD-inhibited cell viability and attenuated OGD-caused alterations in the TGF-β/Smad signaling. miR-322-5p directly targeted Smurf2 and inhibited Smurf2 expression. In OGD-injured H9c2 cells, Smurf2 knockdown exerted similar effects to miR-322-5p overexpression upon cell viability and TGF-β/Smad signaling; moreover, Smurf2 knockdown partially attenuated miR-322-5p inhibition effects on OGD-injured H9c2 cells. In conclusion, miR-322-5p is downregulated in MI rat heart and OGD-stimulated rat cardiomyocytes; the miR-322-5p/Smurf2 axis improves OGD-inhibited cardiomyocyte cell viability and MI-induced cardiac injuries and dysfunction through the TGF-β/Smad signaling.