Protective Effects of the Soluble Receptor for Advanced Glycation End-Products on Pyroptosis during Myocardial Ischemia-Reperfusion

Soluble RAGE attenuates myocardial I/R injury by suppressing interleukin-6

BACKGROUND

Inflammatory responses play a central role in myocardial ischemia/reperfusion (I/R) injury. Previous studies have demonstrated that the receptor for advanced glycation end-products (RAGE) is involved in the pro-inflammatory process of myocardial I/R injury by binding to diverse ligands. Thus, the inhibitory effects of soluble receptor for advanced glycation end-products (sRAGE), a decoy receptor for RAGE, on myocardial I/R injury may be associated with a reduced inflammatory state.

METHODS

In this study, plasma levels of several inflammatory mediators were measured in patients with acute myocardial infarction (AMI) and I/R-treated cardiomyocyte-specific sRAGE knock-in (sRAGE-CKI) mice. Cardiac function, infarct size, and macrophage phenotypes were examined and documented in mouse hearts.

RESULTS

We enrolled 38 patients diagnosed with myocardial infarction (AMI) [mean age, 58.81 ± 10.40 years] and 26 control with negative coronary arteriographic findings [mean age, 61.84 ± 8.57 years]. The results showed that sRAGE levels were significantly elevated in the AMI patient group compared with the control group (1905.00 [1462.50, 2332.5] vs 1570.00 [1335.00, 1800.00] pg/mL, p < 0.05), which were negatively correlated with interleukin (IL)-1, IL-6, and IL-8 levels. Cardiac-specific overexpression of sRAGE dramatically improved cardiac function and reduced infarct size during myocardial I/R. Furthermore, sRAGE overexpression decreased the plasma IL-6 levels and pro-inflammatory iNOS+ M1-macrophages, and increased CD206+ M2-macrophages in the mouse hearts.

CONCLUSIONS

Our findings suggested that sRAGE protects the heart from myocardial I/R injury by inhibiting the infiltration of pro-inflammatory M1-macrophages, and subsequently decreasing IL-6 secretion.

Pyroptosis in myocardial ischemia/reperfusion and its therapeutic implications

Ischemic heart disease, a prevalent cardiovascular disease with global significance, is associated with substantial morbidity. Timely and successful reperfusion is crucial for reducing infarct size and enhancing clinical outcomes. However, reperfusion may induce additional myocardium injury, manifesting as myocardial ischemia/reperfusion (MI/R) injury. Pyroptosis is a regulated cell death pathway, the signaling pathway of which is activated during MI/R injury. In this process, the inflammasomes are triggered, initiating the cleavage of gasdermin proteins and pro-interleukins, which results in the formation of membrane pores and the maturation and secretion of inflammatory cytokines. Numerous preclinical evidence underscores the pivotal role of pyroptosis in MI/R injury. Inhibiting pyroptosis is cardioprotective against MI/R injury. Although certain agents exhibiting promise in preclinical studies for attenuating MI/R injury through inhibiting pyroptosis have been identified, the suitability of these compounds for clinical trials remains untested. This review comprehensively summarizes the recent developments in this field, with a specific emphasis on the impact of pyroptosis on MI/R injury. Deciphering these findings not only sheds light on new disease mechanisms but also paves the way for innovative treatments. And then the exploration of the latest advances in compounds that inhibit pyroptosis in MI/R is discussed, which aims to provide insights into potential therapeutic strategies and identify avenues for future research in the pursuit of effective clinical interventions.

Identification of immune-related genes in acute myocardial infarction based on integrated bioinformatical methods and experimental verification

Background

Acute myocardial infarction (AMI) is one of the leading causes of death worldwide. The etiology of AMI is complex and has not been fully defined. In recent years, the role of immune response in the development, progression and prognosis of AMI has received increasing attention. The aim of this study was to identify key genes associated with the immune response in AMI and to analyze their immune infiltration.

Methods

The study included a total of two GEO databases, containing 83 patients with AMI and 54 healthy individuals. We used the linear model of microarray data (limma) package to find the differentially expressed genes associated with AMI, performing weighted gene co-expression analysis (WGCNA) to further identify the genes associated with inflammatory response to AMI. We found the final hub genes through the protein-protein interaction (PPI) network and least absolute shrinkage and selection operator (LASSO) regression model. To verify the above conclusions, we constructed mice AMI model, extracting myocardial tissue to perform qRT-PCR. Furthermore, the CIBERSORT tool for immune cells infiltration analysis was also carried out.

Results

A total of 5,425 significant up-regulated and 2,126 down-regulated genes were found in GSE66360 and GSE24519. A total of 116 immune-related genes in close association with AMI were screened by WGCNA analysis. These genes were mostly clustered in the immune response on the basis of GO and KEGG enrichment. With construction of PPI network and LASSO regression analysis, this research found three hub genes (SOCS2, FFAR2, MYO10) among these differentially expressed genes. The immune cell infiltration results revealed that significant differences could be found on T cells CD4 memory activated, Tregs (regulatory T cells), macrophages M2, neutrophils, T cells CD8, T cells CD4 naive, eosinophils between controls and AMI patients.

Scavenger Receptors in Myocardial Infarction and Ischemia/Reperfusion Injury: The Potential for Disease Evaluation and Therapy

Scavenger receptors (SRs) are a structurally heterogeneous superfamily of evolutionarily conserved receptors that are divided into classes A to J. SRs can recognize multiple ligands, such as modified lipoproteins, damage-associated molecular patterns, and pathogen-associated molecular patterns, and regulate lipid metabolism, immunity, and homeostasis. According to the literature, SRs may play a critical role in myocardial infarction and ischemia/reperfusion injury, and the soluble types of SRs may be a series of promising biomarkers for the diagnosis and prognosis of patients with acute coronary syndrome or acute myocardial infarction. In this review, we briefly summarize the structure and function of SRs and discuss the association between each SR and ischemic cardiac injury in patients and animal models in detail. A better understanding of the effect of SRs on ischemic cardiac injury will inspire novel ideas for therapeutic drug discovery and disease evaluation in patients with myocardial infarction.

A Study on the Protective Effect of sRAGE-MSCs in a Rodent Reperfusion Model of Myocardial Infarction

Acute myocardial infarction (AMI) is one of the major leading causes of death in humans globally. Recently, increased levels of recruited macrophages and AGE-albumin were observed in the hearts of humans and animals with acute myocardial infarction. Thus, the purposes of this study were to investigate whether the elevated levels of AGE-albumin from activated macrophage cells are implicated in ischemia-induced cardiomyocyte death and to develop therapeutic strategies for AMI based on its underlying molecular mechanisms with respect to AGEs. The present study demonstrated that activated macrophages and AGE-albumin were observed in heart tissues obtained from humans and rats with AMI incidences. In the cellular model of AMI, it was found that increased expression of AGE-albumin was shown to be co-localized with macrophages, and the presence of AGE-albumin led to increased expression of RAGE through the mitogen-activated protein kinase pathway. After revealing cardiomyocyte apoptosis induced by toxicity of the AGE-RAGE system, sRAGE-secreting MSCs were generated using the CRISPR/Cas9 platform to investigate the therapeutic effects of sRAGE-MSCs in an AMI rat model. Gene-edited sRAGE-MSCs showed greater therapeutic effects against AMI pathogenesis in rat models compared to mock MSCs, and promising results of the functional improvement of stem cells could result in significant improvements in the clinical management of cardiovascular diseases.

Pyroptosis: A Newly Discovered Therapeutic Target for Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury, uncommon among patients suffering from myocardial infarction, stroke, or acute kidney injury, can result in cell death and organ dysfunction. Previous studies have shown that different types of cell death, including apoptosis, necrosis, and autophagy, can occur during I/R injury. Pyroptosis, which is characterized by cell membrane pore formation, pro-inflammatory cytokine release, and cell burst, and which differentiates itself from apoptosis and necroptosis, has been found to be closely related to I/R injury. Therefore, targeting the signaling pathways and key regulators of pyroptosis may be favorable for the treatment of I/R injury, which is far from adequate at present. This review summarizes the current status of pyroptosis and its connection to I/R in different organs, as well as potential treatment strategies targeting it to combat I/R injury.

Cardiac Remodeling in Heart Failure: Role of Pyroptosis and Its Therapeutic Implications

Pyroptosis is a kind of programmed cell death closely related to inflammation. The pathways that mediate pyroptosis can be divided into the Caspase-1-dependent canonical pathway and the Caspase4/5/11-dependent non-canonical pathway. The most significant difference from other cell death is that pyroptosis rapidly causes rupture of the plasma membrane, cell expansion, dissolution and rupture of the cell membrane, the release of cell contents and a large number of inflammatory factors, and send pro-inflammatory signals to adjacent cells, recruit inflammatory cells and induce inflammatory responses. Cardiac remodeling is the basic mechanism of heart failure (HF) and the core of pathophysiological research on the underlying mechanism. A large number of studies have shown that pyroptosis can cause cardiac fibrosis, cardiac hypertrophy, cardiomyocytes death, myocardial dysfunction, excessive inflammation, and cardiac remodeling. Therefore, targeting pyroptosis has a good prospect in improving cardiac remodeling in HF. In this review, the basic molecular mechanism of pyroptosis is summarized, the relationship between pyroptosis and cardiac remodeling in HF is analyzed in-depth, and the potential therapy of targeting pyroptosis to improve adverse cardiac remodeling in HF is discussed, providing some ideas for improving the study of adverse cardiac remodeling in HF.