Endothelial Autophagy in Coronary Microvascular Dysfunction and Cardiovascular Disease

Characterization of microcirculatory endothelial functions in a D-Galactose-induced aging model

BACKGROUND

Microcirculation health is critical to human health, and aging is an important factor affecting microcirculation health. Although D-Galactose has been widely used in aging research models, there is a lack of relevant studies on D-Galactose simulating microcirculatory aging. Here, we explored microcirculatory endothelial function in D-Galactose-induced aging mice.

METHODS

Intraperitoneal injection of 150 mg/(kg·d) of D-Galactose was given to cause senescence in mice. Aging was evaluated by SA-β-gal (senescence-associated β-galactosidase) staining. The auricular skin and hepatic microcirculation of mice were observed and detected by enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC) and microcirculation apparatus. The aging of microcirculation was analyzed from oxidative stress, endothelial impairment, inflammation, microvascular morphology and hemodynamics.

RESULTS

In aging mice, percentage of SA-β-gal positive area, oxidative stress products reactive oxygen species (ROS) and nitric oxide (NO), endothelial impairment marker syndecan-1 (SDC-1), stromal cell derived factor-1 (SDF-1), intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in the senescence-associated secretory phenotype (SASP) were all up-regulated. The tortuosity of microvessels increased in aging mice, the linear density did not change significantly, but the total length of narrow microvessels (TLNMV) increased and wide microvessels (TLWMV) decreased, speculate that vasomotor dysfunction may be present. Hemodynamically, both perfusion and velocity of blood flow were reduced in senescent mice, presumably due to endothelial dysfunction.

CONCLUSION

Microcirculatory endothelial dysfunction is induced by D-Galactose, leading to microcirculatory aging. In vivo, this is manifested by elevated levels of oxidative stress, impaired endothelial glycocalyx (eGC), and a greater production of chemokines and adhesive molecules. These changes cause vasomotor dysfunction and remodeling, ultimately leading to hemodynamic impairment.

Potential preservative mechanisms of cardiac rehabilitation pathways on endothelial function in coronary heart disease

Cardiac rehabilitation, a comprehensive exercise-based lifestyle and medical management, is effective in decreasing morbidity and improving life quality in patients with coronary heart disease. Endothelial function, an irreplaceable indicator in coronary heart disease progression, is measured by various methods in traditional cardiac rehabilitation pathways, including medicinal treatment, aerobic training, and smoking cessation. Nevertheless, studies on the effect of some emerging cardiac rehabilitation programs on endothelial function are limited. This article briefly reviewed the endothelium-beneficial effects of different cardiac rehabilitation pathways, including exercise training, lifestyle modification and psychological intervention in patients with coronary heart disease, and related experimental models, and summarized both uncovered and potential cellular and molecular mechanisms of the beneficial roles of various cardiac rehabilitation pathways on endothelial function. In exercise training and some lifestyle interventions, the enhanced bioavailability of nitric oxide, increased circulating endothelial progenitor cells (EPCs), and decreased oxidative stress are major contributors to preventing endothelial dysfunction in coronary heart disease. Moreover, the preservation of endothelial-dependent hyperpolarizing factors and inflammatory suppression play roles. On the one hand, to develop more endothelium-protective rehabilitation methods in coronary heart disease, adequately designed and sized randomized multicenter clinical trials should be advanced using standardized cardiac rehabilitation programs and existing assessment methods. On the other hand, additional studies using suitable experimental models are warranted to elucidate the relationship between some new interventions and endothelial protection in both macro- and microvasculature.

The role of nonmyocardial cells in the development of diabetic cardiomyopathy and the protective effects of FGF21: a current understanding

Diabetic cardiomyopathy (DCM) represents a unique myocardial disease originating from diabetic metabolic disturbances that is characterized by myocardial fibrosis and diastolic dysfunction. While recent research regarding the pathogenesis and treatment of DCM has focused primarily on myocardial cells, nonmyocardial cells-including fibroblasts, vascular smooth muscle cells (VSMCs), endothelial cells (ECs), and immune cells-also contribute significantly to the pathogenesis of DCM. Among various therapeutic targets, fibroblast growth factor 21 (FGF21) has been identified as a promising agent because of its cardioprotective effects that extend to nonmyocardial cells. In this review, we aim to elucidate the role of nonmyocardial cells in DCM and underscore the potential of FGF21 as a therapeutic strategy for these cells.

PANoptosis and cardiovascular disease: The preventive role of exercise training

Regulated cell death, including pyroptosis, apoptosis, and necroptosis, is vital for the body's defense system. Recent research suggests that these three types of cell death are interconnected, giving rise to a new concept called PANoptosis. PANoptosis has been linked to various diseases, making it crucial to comprehend its mechanism for effective treatments. PANoptosis is controlled by upstream receptors and molecular signals, which form polymeric complexes known as PANoptosomes. Cell death combines necroptosis, apoptosis, and pyroptosis and cannot be fully explained by any of these processes alone. Understanding pyroptosis, apoptosis, and necroptosis is essential for understanding PANoptosis. Physical exercise has been shown to suppress pyroptotic, apoptotic, and necroptotic signaling pathways by reducing inflammatory factors, proapoptotic factors, and necroptotic factors such as caspases and TNF-alpha. This ultimately leads to a decrease in cardiac structural remodeling. The beneficial effects of exercise on cardiovascular health may be attributed to its ability to inhibit these cell death pathways.

The role and mechanism of action of miR‑92a in endothelial cell autophagy

Although microRNAs (miRNAs/miRs) serve a significant role in the autophagy of vascular endothelial cells (ECs), the effect of miR‑92a on the autophagy of ECs is currently unclear. Therefore, the present study aimed to investigate the impact of miR‑92a on autophagy in ECs and the underlying molecular processes that control this biological activity. Firstly, an autophagy model of EA.hy926 cells was generated via treatment with the autophagy inducer rapamycin (rapa‑EA.hy926 cells). The expression levels of miR‑92a were then detected by reverse transcription‑quantitative PCR, and the effect of miR‑92a expression on the autophagic activity of rapa‑EA.hy926 cells was studied by overexpressing or inhibiting miR‑92a. The level of autophagy was evaluated by western blot analysis, immunofluorescence staining and transmission electron microscopy. Dual‑luciferase reporter assays were used to confirm the interaction between miR‑92a and FOXO3. The results demonstrated that the expression levels of miR‑92a were decreased in the rapa‑EA.hy926 cell autophagy model. Furthermore, overexpression and inhibition of miR‑92a revealed that upregulation of miR‑92a in these cells inhibited autophagy, whereas miR‑92a knockdown promoted it. It was also confirmed that miR‑92a directly bound to the 3'‑untranslated region of the autophagy‑related gene FOXO3 and reduced its expression. In conclusion, the present study suggested that miR‑92a inhibits autophagy activity in EA.hy926 cells by targeting FOXO3.

MiR-106a targets ATG7 to inhibit autophagy and angiogenesis after myocardial infarction

BACKGROUND

Myocardial infarction (MI) is an acute condition in which the heart muscle dies due to the lack of blood supply. Previous research has suggested that autophagy and angiogenesis play vital roles in the prevention of heart failure after MI, and miR-106a is considered to be an important regulatory factor in MI. But the specific mechanism remains unknown. In this study, using cultured venous endothelial cells and a rat model of MI, we aimed to identify the potential target genes of miR-106a and discover the mechanisms of inhibiting autophagy and angiogenesis.

METHODS

We first explored the biological functions of miR-106a on autophagy and angiogenesis on endothelial cells. Then we identified ATG7, which was the downstream target gene of miR-106a. The expression of miR-106a and ATG7 was investigated in the rat model of MI.

RESULTS

We found that miR-106a inhibits the proliferation, cell cycle, autophagy and angiogenesis, but promoted the apoptosis of vein endothelial cells. Moreover, ATG7 was identified as the target of miR-106a, and ATG7 rescued the inhibition of autophagy and angiogenesis by miR-106a. The expression of miR-106a in the rat model of MI was decreased but the expression of ATG7 was increased in the infarction areas.

CONCLUSION

Our results indicate that miR-106a may inhibit autophagy and angiogenesis by targeting ATG7. This mechanism may be a potential therapeutic treatment for MI.

EASIX and cardiac adverse events after allogeneic hematopoietic cell transplantation

This study investigates the interaction between endothelial activation, indirectly measured using EASIX, and the probability of presenting cardiac adverse events (CAE) during the first year after allo-HCT. The 437 consecutive adults undergoing PB allo-HCT from 2012 and 2021 were included. EASIX was retrospectively calculated before and during the first 6 months after allo-HCT and transformed to log2-base to conduct the statistical analysis. The median age was 53, 46 (10.5%) patients had previous history of cardiac disease, MAC allo-HCTs were performed in 186 (42.6%) patients, and PTCY was administered in 242 (55.5%). The 1-year incidence of CAE was 12.6% (n = 55). The most prevalent cardiac events were heart failure and arrhythmias, 32.7% and 23.6% respectively, and the day +100 mortality rate of these patients was 40.5%. During the first 6 months after allo-HCT, EASIX trends were significantly higher in patients who developed CAE. Regression analyses confirmed that higher log2-EASIX values were predictors for higher risk for CAE during the first year after allo-HCT. This analysis identifies a significant association between higher endothelial activation, indirectly measured using EASIX, and higher risk for cardiac toxicity diagnosed during the first year after allo-HCT and extends the applicability of EASIX for identifying patients at risk for CAE.

The role of IFI16 in regulating PANoptosis and implication in heart diseases

Interferon Gamma Inducible Protein 16 (IFI16) belongs to the HIN-200 protein family and is pivotal in immunological responses. Serving as a DNA sensor, IFI16 identifies viral and aberrant DNA, triggering immune and inflammatory responses. It is implicated in diverse cellular death mechanisms, such as pyroptosis, apoptosis, and necroptosis. Notably, these processes are integral to the emergent concept of PANoptosis, which encompasses cellular demise and inflammatory pathways. Current research implies a significant regulatory role for IFI16 in PANoptosis, particularly regarding cardiac pathologies. This review delves into the complex interplay between IFI16 and PANoptosis in heart diseases, including atherosclerosis, myocardial infarction, heart failure, and diabetic cardiomyopathy. It synthesizes evidence of IFI16's impact on PANoptosis, with the intention of providing novel insights for therapeutic strategies targeting heart diseases.

Melatonin alleviates myocardial dysfunction through inhibition of endothelial-to-mesenchymal transition via the NF-κB pathway

Endothelial-to-mesenchymal transition (EndMT) is a complex biological process of cellular transdifferentiation by which endothelial cells (ECs) lose their characteristics and acquire mesenchymal properties, leading to cardiovascular remodeling and complications in the adult cardiovascular diseases environment. Melatonin is involved in numerous physiological and pathological processes, including aging, and has anti-inflammatory and antioxidant activities. This molecule is an effective therapeutic candidate for preventing oxidative stress, regulating endothelial function, and maintaining the EndMT balance to provide cardiovascular protection. Although recent studies have documented improved cardiac function by melatonin, the mechanism of action of melatonin on EndMT remains unclear. The present study investigated the effects of melatonin on induced EndMT by transforming growth factor-β2/interleukin-1β in both in vivo and in vitro models. The results revealed that melatonin reduced the migratory ability and reactive oxygen species levels of the cells and ameliorated mitochondrial dysfunction in vitro. Our findings indicate that melatonin prevents endothelial dysfunction and inhibits EndMT by activating related pathways, including nuclear factor kappa B and Smad. We also demonstrated that this molecule plays a crucial role in restoring cardiac function by regulating the EndMT process in the ischemic myocardial condition, both in vessel organoids and myocardial infarction (MI) animal models. In conclusion, melatonin is a promising agent that attenuates EC dysfunction and ameliorates cardiac damage compromising the EndMT process after MI.

New Dawn for Atherosclerosis: Vascular Endothelial Cell Senescence and Death

Endothelial cells (ECs) form the inner linings of blood vessels, and are directly exposed to endogenous hazard signals and metabolites in the circulatory system. The senescence and death of ECs are not only adverse outcomes, but also causal contributors to endothelial dysfunction, an early risk marker of atherosclerosis. The pathophysiological process of EC senescence involves both structural and functional changes and has been linked to various factors, including oxidative stress, dysregulated cell cycle, hyperuricemia, vascular inflammation, and aberrant metabolite sensing and signaling. Multiple forms of EC death have been documented in atherosclerosis, including autophagic cell death, apoptosis, pyroptosis, NETosis, necroptosis, and ferroptosis. Despite this, the molecular mechanisms underlying EC senescence or death in atherogenesis are not fully understood. To provide a comprehensive update on the subject, this review examines the historic and latest findings on the molecular mechanisms and functional alterations associated with EC senescence and death in different stages of atherosclerosis.

LINC00346 regulates NLRP1-mediated pyroptosis and autophagy via binding to microRNA-637 in vascular endothelium injury

Endothelial injury and dysfunction contributes to atherosclerosis. LINC00346 plays a key role in vascular endothelial cell injury, however, the specific mechanism remains unclear. This study intends to further explore the relationship between LINC00346 and vascular endothelial injury. Circulating LINC00346 was significantly elevated in patients with coronary artery disease and had high diagnostic value for coronary artery disease. In cell experiments, we found that LINC00346 expression was significantly increased in the oxidized low-density lipoprotein (ox-LDL) intervention group, and LINC00346 knockdown delayed ox-LDL induced human umbilical vein endothelial cell (HUVEC) endothelial-to-mesenchymal transition. In addition, knockdown of LINC00346 mitigated ox-LDL-induced NOD-like receptor protein 1 (NLRP1)-mediated inflammasome formation and pyroptosis, but had no significant effect on NLRP3. By observing the number of autophagosome and detecting intracellular autophagic flux, we found that LINC00346 knockdown inhibited the ox-LDL-induced increase in intracellular autophagy level. Dual-luciferase reporter assay, RNA immunoprecipitation assay, and RNA-pull down assay were performed to confirm the inter-molecular interaction. LINC00346 acted as microRNA-637 sponge to up-regulate the expression of NLRP1. Up-regulation of microRNA-637 alleviated NLRP1-mediated pyroptosis in HUVEC and reduced intracellular autophagosome and autolysosome formation. Finally, we explored whether pyropotosis and autophagy interact with each other. We found that inhibition of intracellular autophagy could alleviate NLRP1-mediated pyroptosis. In conclusion, LINC00346 inhibited the activation of NLRP1-mediated pyroptosis and autophagy via binding to microRNA-637, therefore mitigating vascular endothelial injury.

Circulating miRNA-451a and miRNA-328-3p as Potential Markers of Coronary Artery Aneurysmal Disease

MicroRNAs (miRNAs) are currently investigated as crucial regulatory factors which may serve as a potential therapeutic target. Reports on the role of miRNA in patients with coronary artery aneurysmal disease (CAAD) are limited. The present analysis aims to confirm the differences in the expression of previously preselected miRNAs in larger study groups and evaluate their usefulness as potential markers of CAAD. The study cohort included 35 consecutive patients with CAAD (Group 1), and two groups of 35 patients matched Group 1 regarding sex and age from the overall cohort of 250 patients (Group 2 and Group 3). Group 2 included patients with angiographically documented coronary artery disease (CAD), while Group 3 enrolled patients with normal coronary arteries (NCA) assessed during coronary angiography. We applied the RT-qPCR method using the custom plates for the RT-qPCR array. We confirmed that the level of five preselected circulating miRNAs was different in patients with CAAD compared to Group 2 and Group 3. We found that miR-451a and miR-328 significantly improved the CAAD prediction. In conclusion, miR-451a is a significant marker of CAAD compared to patients with CAD. In turn, miR-328-3p is a significant marker of CAAD compared to patients with NCA.

Stomatin-like protein 2 deficiency exacerbates adverse cardiac remodeling

Myocardial fibrosis, oxidative stress, and autophagy both play key roles in the progression of adverse cardiac remodeling. Stomatin-like protein 2 (SLP-2) is closely related to mitochondrial function, but little is known about its role and mechanism in cardiac remodeling. We developed doxorubicin (Dox), angiotensin (Ang) II, and myocardial ischemia-reperfusion (I/R) injury induced cardiac remodeling model and Dox treated H9C2 cell injury model using SLP-2 knockout (SLP-2^-/-) mice and H9C2 cells with low SLP-2 expression. We first examined cardiac functional and structural changes as well as levels of oxidative stress, apoptosis and autophagy. We found that SLP-2 deficiency leads to decreased cardiac function and promotes myocardial fibrosis. After Dox and Ang II treatment, SLP-2 deficiency further aggravated myocardial fibrosis, increased myocardial oxidative stress and apoptosis, and activated autophagy by inhibiting PI3K-Akt-mTOR signaling pathway, ultimately exacerbating adverse cardiac remodeling. Similarly, SLP-2 deficiency further exacerbates adverse cardiac remodeling after myocardial I/R injury. Moreover, we extracted cardiomyocyte mitochondria for proteomic analysis, suggesting that SLP-2 deficiency may be involved in myocardial I/R injury induced adverse cardiac remodeling by influencing ubiquitination of intramitochondrial proteins. In addition, the oxidative stress, apoptosis and autophagy levels of H9C2 cells with low SLP-2 expression were further enhanced, and the PI3K-Akt-mTOR signaling pathway was further inhibited under Dox stimulation. Our results suggest that SLP-2 deficiency promotes myocardial fibrosis, disrupts normal mitochondrial function, overactivates autophagy via PI3K-Akt-mTOR signaling pathway, affects the level of ubiquitination, leads to irreversible myocardial damage, and ultimately exacerbates adverse cardiac remodeling.

Potential roles of endothelial cells-related non-coding RNAs in cardiovascular diseases

Endothelial dysfunction is identified by a conversion of the endothelium toward decreased vasodilation and prothrombic features and is known as a primary pathogenic incident in cardiovascular diseases. An insight based on particular and promising biomarkers of endothelial dysfunction may possess vital clinical significances. Currently, non-coding RNAs due to their participation in critical cardiovascular processes like initiation and progression have gained much attention as possible diagnostic as well as prognostic biomarkers in cardiovascular diseases. Emerging line of proof has demonstrated that abnormal expression of non-coding RNAs is nearly correlated with the pathogenesis of cardiovascular diseases. In the present review, we focus on the expression and functional effects of various kinds of non-coding RNAs in cardiovascular diseases and negotiate their possible clinical implications as diagnostic or prognostic biomarkers and curative targets.