miR-24 Alleviates MI/RI by Blocking the S100A8/TLR4/MyD88/NF-kB Pathway

MicroRNA-24 therapeutic potentials in infarction, stroke, and diabetic complications

The prevalence of cardiovascular events, stroke, and diabetes worldwide underscores the urgent need for effective and minimally invasive treatments. With nearly 20 million annual casualties attributed to cardiovascular diseases and an estimated 463 million people living with diabetes in 2022. Identifying promising therapeutic candidates is paramount. MicroRNAs, short nucleic acids involved in regulating gene expression, emerge as potential game-changers. Among these, microRNA-24 (miR-24), a hypoxia-sensitive player in endothelial vessels, has protective roles against diverse vascular complications. Following heart infarction and stroke, elevating miR-24 expression proves beneficial by mitigating oxidative stress, inflammation, and apoptosis while enhancing cell survival. It reduces cardiac fibrosis in heart disease, regulates aberrant angiogenesis in cerebral hemorrhagic strokes, and enhances the functionality of cardiomyocytes and brain neurons. In diabetic conditions, augmenting miR-24 expression mitigates complications. Further, being miR-24 also expressed by the skeletal muscle (i.e., myo-miR) in response to exercise, this miRNA may participate in the complex molecular network that systemically spreads the beneficial effects of physical exercise. This review provides a comprehensive vision of the molecular mechanisms underpinning the miR-24 protective effects, offering new insights into its therapeutic potential and proposing a novel avenue for medical intervention.

MiR-24 regulates obstructive pulmonary disease in rats via S100A8

PURPOSE

Chronic obstructive pulmonary disease (COPD) is a persistent inflammatory disorder characterized by minor airway inflammation and emphysema involving various cell types and cytokines. MicroRNAs (miRNAs) have emerged as critical regulators in the pathogenesis of lung diseases. This study investigates the impact of microRNA-24 (miR-24) on airway inflammatory responses in a rat model of COPD.

MATERIALS AND METHODS

The model was established by combining cigarette smoke exposure and lipopolysaccharide stimulation, and rat lung tissues were transfected with adeno-associated viruses overexpressing miR-24. Pathological changes in the lung were assessed using hematoxylin and eosin staining. Levels of pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-6, and interleukin-8, were measured using enzyme-linked immunosorbent assay. Expression of miR-24 and S100A8 was detected through quantitative reverse transcription PCR, while protein levels of S100A8, Toll-like receptor 4 (TLR4), and myeloid differentiation primary response 88 (MyD88) were assessed using western blotting. Bioinformatics analysis and dual-luciferase reporter assay were performed to determine the relationship between S100A8 and miR-24.

RESULTS

The results demonstrated the downregulation of miR-24 in rats with COPD, and its overexpression resulted in a significant decrease in S1008 mRNA levels. Additionally, the protein level of S100A8 was significantly increased in the lung tissues of COPD rats. The upregulation of miR-24, however, not only inhibited the protein expression of S100A8, TLR4, and MyD88 in lung tissues but also reduced the release of pro-inflammatory cytokines in the plasma and bronchoalveolar lavage fluid, thereby attenuating inflammatory responses and pathological injuries in the lung.

CONCLUSIONS

Our data suggest that miR-24 attenuates airway inflammatory responses in COPD by inhibiting the TLR4/MyD88 pathway via targeting S100A8.

The Role of Alarmins in the Pathogenesis of Atherosclerosis and Myocardial Infarction

Atherosclerosis is a condition that is associated with lipid accumulation in the arterial intima. Consequently, the enlarging lesion, which is also known as an atherosclerotic plaque, may close the blood vessel lumen, thus leading to organ ischaemia. Furthermore, the plaque may rupture and initiate the formation of a thrombus, which can cause acute ischaemia. Atherosclerosis is a background pathological condition that can eventually lead to major cardiovascular diseases such as acute coronary syndrome or ischaemic stroke. The disorder is associated with an altered profile of alarmins, stress response molecules that are secreted due to cell injury or death and that induce inflammatory responses. High-mobility group box 1 (HMGB1), S100 proteins, interleukin-33, and heat shock proteins (HSPs) also affect the behaviour of endothelial cells and vascular smooth muscle cells (VSMCs). Thus, alarmins control the inflammatory responses of endothelial cells and proliferation of VSMCs, two important processes implicated in the pathogenesis of atherosclerosis. In this review, we will discuss the role of alarmins in the pathophysiology of atherosclerosis and myocardial infarction.

The Role of ncRNAs in Cardiac Infarction and Regeneration

Myocardial infarction is the most prevalent cardiovascular disease worldwide, and it is defined as cardiomyocyte cell death due to a lack of oxygen supply. Such a temporary absence of oxygen supply, or ischemia, leads to extensive cardiomyocyte cell death in the affected myocardium. Notably, reactive oxygen species are generated during the reperfusion process, driving a novel wave of cell death. Consequently, the inflammatory process starts, followed by fibrotic scar formation. Limiting inflammation and resolving the fibrotic scar are essential biological processes with respect to providing a favorable environment for cardiac regeneration that is only achieved in a limited number of species. Distinct inductive signals and transcriptional regulatory factors are key components that modulate cardiac injury and regeneration. Over the last decade, the impact of non-coding RNAs has begun to be addressed in many cellular and pathological processes including myocardial infarction and regeneration. Herein, we provide a state-of-the-art review of the current functional role of diverse non-coding RNAs, particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in different biological processes involved in cardiac injury as well as in distinct experimental models of cardiac regeneration.

Evaluation of Students' Online Learning Behavior and Perception of Psychological State Based on Data Mining

This paper first analyzes the characteristics of students' OLB and stimulates students' online learning motivation based on the locus of control (LoC) stimulation model. Through data mining technology, this paper puts forward the analysis model of OLB, the sequence mining model of OLB, and the interactive model of OLB. Finally, a psychological state perception model based on OLB analysis is constructed; MAE and MSE are used as indexes to compare the fitting effects of GBRT, AdaBoostRegression, LinearSVR, and LinearRegression algorithms on the model. The results show that the relationship between students' psychological state and OLB is very close. While the model constructed has certain predictive ability for students' psychological state perception of OLB, which has certain practical significance for the regulation of students' learning behavior.