Cardiac remodeling is a common pathophysiological change associated with acute myocardial infarction (AMI). Recent evidence indicates that microRNAs are strong posttranscriptional regulators which play an important role in regulating the microenvironment of myocardial tissue after AMI. In this study, we sought to explore the potential role and underlying mechanism of miR-130 in AMI. H9c2 cells were cultured under hypoxic conditions to simulate myocardial infarction. The influence of aberrantly expressed miR-130 on H9c2 cells under hypoxia was also estimated with RT-PCR, western blot and enzyme-linked immunosorbent assay. Using bioinformatics methods, of miR-130 target genes were verified with luciferase reporter assay. Then, the effects of miR-130 on AMI were identified in an induced myocardial injury model in rats. The results show that miR-130 downregulation remarkably decreased hypoxia-induced inflammation and fibrosis related protein expression in H9c2 cells and reversed hypoxia-induced peroxisome proliferator-activated receptor γ (PPAR-γ) inhibition. A bifluorescein reporter assay further confirmed that PPAR-γ was a target gene of miR-130. This study verified that PPAR-γ has a cardioprotective effect by inhibiting NFκB-mediated inflammation and TGF-β1-mediated fibrosis. In vivo experiments confirmed that downregulation of miR-130 expression promotes PPAR-γ-mediated cardioprotective effects by suppressing inflammation and myocardial fibrosis. Taken together, these findings suggest that miR-130 knockdown alleviates infarction-induced myocardial injury by promoting PPAR-γ expression.
Background Cardiac arrest (CA) is a leading cause of death worldwide. Even after successful cardiopulmonary resuscitation (CPR), the majorities of survivals are companied with permanent myocardial and cerebral injury. Hydrogen sulfide (H2S) has been recognized as a novel gasotransmitter exerting multiple organ protection; however, the lacks of ideal H2S donors which can controlled release H2S to targeted organs such as heart and brain limits its application. Results This work utilized mesoporous iron oxide nanoparticle (MION) as the carriers of diallyl trisulfide (DATS), with polyethylene glycol (PEG) and lactoferrin (LF) modified to MIONs to acquire the prolonged circulation time and brain-targeting effects, and a novel targeted H2S releasing system was constructed (DATS@MION-PEG-LF), which exhibited excellent biocompatibility, controlled-releasing H2S pattern, heart and brain targeting features, and the ability to be non-invasive traced by magnetic resonance imaging. DATS@MION-PEG-LF presented potent protective effects against cerebral and cardiac ischemic injury after CA in both in vitro hypoxia/reoxygenation models and in vivo CA/CPR models, which mainly involves anti-apoptosis, anti-inflammatory and anti-oxidant mechanisms. Accordingly, the cardiac and cerebral functions were obviously improved after CA/CPR, with potentially improved survival. Conclusions The present work provides a unique platform for targeted controlled release of H2S based on MIONs, and offers a new method for combinational myocardial and cerebral protection from ischemic injury, bringing considerable benefits for CA patients.
Myocardial infarction (MI) leads to cardiac remodelling and heart failure. Cardiomyocyte apoptosis is considered a critical pathological phenomenon accompanying MI, but the pathogenesis mechanism remains to be explored. MicroRNAs (miRs), with the identity of negative regulator of gene expression, exist as an important contributor to apoptosis. During the experiment of this study, MI mice models were successfully established and sequencing data showed that the expression of miR-23a-5p was significantly enhanced during MI progression. Further steps were taken and it showed that apoptosis of cardiac cells weakened as miR-23a-5p was downregulated and on the contrary that apoptosis strengthened with the overexpression of miR-23a-5p. To explore its working mechanisms, bioinformatics analysis was conducted by referring to multi-databases to predict the targets of miR-23a-5p. Further analysis suggested that those downstream genes enriched in several pathways, especially in the PI3K/Akt singling pathway. Furthermore, it demonstrated that miR-23a-5p was negatively related to the phosphorylation of PI3K/Akt, which plays a critical role in triggering cell apoptosis during MI. Recilisib-activated PI3K/Akt singling pathway could restrain apoptosis from inducing miR-23a-5p overexpression, and Miltefosine-blocked PI3K/Akt singling pathway could restrict apoptosis from inhibiting miR-23a-5p reduction. In conclusion, these findings revealed the pivotal role of miR-23a-5p-PI3K/Akt axis in regulating apoptosis during MI, introducing this novel axis as a potential indicator to detect ischemic heart disease and it could be used for therapeutic intervention.
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