Autophagy and Oncosis/Necroptosis Are Enhanced in Cardiomyocytes from Heart Failure Patients

Identification of Necroptosis and Immune Infiltration in Heart Failure Through Bioinformatics Analysis

Purpose

Heart failure (HF) remains a leading cause of mortality and morbidity in cardiovascular disease. Research has shown that necroptosis contributes to HF, and immune infiltration has been reported to be implicated in HF. However, the specific mechanisms by which necroptosis and immune infiltration promote HF remain poorly understood. This study aims to elucidate these mechanisms, thereby providing new insights for future therapeutic strategies.

Methods and Results

In the GSE21610 dataset, there were 1848 differentially expressed genes (DEGs), 14 of which related to necroptosis (NRDEGs) in HF. Gene Set Enrichment Analysis (GSEA) indicated that Th1 and Th2 cell differentiation, TGF-beta signaling, Renin secretion, and Wnt signaling pathways may be closely associated with HF. The NRDEGs may play a role in responding to mechanical stimuli, membrane rafts, cytokine receptor binding, or the necroptosis signaling pathway. The protein-protein interaction (PPI) network identified EGFR, TXN, FASLG, MAPK14, and CASP8 as hub NRDEGs. Furthermore, immune infiltration analysis of CIBERSORT algorithm suggested that M2 macrophages, memory B cells, monocytes, regulatory T cells (Tregs), follicular helper T cells, and gamma delta T cells may participate in the development of HF. The hub NRDEGs, including EGFR, FASLG, and TXN, exhibited significant correlations with various immune cell types. Finally, animal models confirmed that in the HF group, EGFR and FASLG were up-regulated, while TXN was down-regulated.

Conclusion

The present findings demonstrate that necroptosis and immune infiltration are associated with the development of HF. This study provides valuable insights and recommendations for the clinical management of HF.

Exploring the therapeutic mechanisms of heart failure with Chinese herbal medicine: a focus on miRNA-mediated regulation

Heart failure (HF) is a clinical condition caused by abnormalities in the heart's structure or function, primarily manifested as diminished ability of the heart to pump blood, which leads to compensatory activation of neurohormones and increased left ventricular filling pressure. HF is one of the fastest-growing cardiovascular diseases globally in terms of incidence and mortality, negatively impacting patients' quality of life and imposing significant medical and economic burdens. Despite advancements in the treatment of HF, hospitalization and mortality remain rates high. In China, Chinese herbal medicine (CHM) has historically played a prominent role in addressing HF, with significant proven efficacy. MicroRNA (miRNA) exerts a pivotal regulatory influence on the maintenance of regular cardiac activity and the progression of HF. MiRNAs, a category of single-stranded RNA molecules, are characterized by their inability to code for proteins. They regulate gene expression by binding to the 3'-untranslated region (3'-UTR) of target mRNAs, thereby influencing the onset and progression of various diseases. Abnormal expression of specific miRNAs is closely associated with HF pathological processes, such as cardiomyocyte apoptosis, myocardial fibrosis, and cardiac hypertrophy. This abnormal expression can influence the pathological progression of HF through the regulation of miRNA expression. This article reviews the regulatory role of miRNAs in HF pathology discusses how CHM compounds and their active ingredients can ameliorate HF pathology through the regulation of miRNA expression. In conclusion, miRNAs represent promising therapeutic targets for HF, and CHM provides a novel strategy for treatment through the regulation of miRNA expression. Future studies must delve deeper into the precise mechanisms by which CHM modulates miRNAs and fully explore its potential for clinical application in HF treatment.

A Need to Preserve Ejection Fraction during Heart Failure

Heart failure (HF) is a significant global healthcare burden with increasing prevalence and high morbidity and mortality rates. The diagnosis and management of HF are closely tied to ejection fraction (EF), a crucial parameter for evaluating disease severity and determining treatment plans. This paper emphasizes the urgent need to maintain EF during heart failure, highlighting the distinct phenotypes of HF with preserved ejection fraction (HFpEF) and HF with reduced ejection fraction (HFrEF). It discusses the complexities of HFrEF pathophysiology and its negative impact on patient outcomes, stressing the importance of ongoing research and the development of effective therapeutic interventions to slow down the progression from preserved to reduced ejection fraction. Additionally, it explores the potential role of renal denervation in preserving ejection fraction and its implications for HFrEF management. This comprehensive review aims to offer valuable insights into the critical role of EF preservation in enhancing outcomes for patients with heart failure.

Importance of Energy, Dietary Protein Sources, and Amino Acid Composition in the Regulation of Metabolism: An Indissoluble Dynamic Combination for Life

PURPOSE

This paper aims to present a unique perspective that emphasizes the intricate interplay between energy, dietary proteins, and amino acid composition, underscoring their mutual dependence for health-related considerations. Energy and protein synthesis are fundamental to biological processes, crucial for the sustenance of life and the growth of organisms.

METHODS AND RESULTS

We explore the intricate relationship between energy metabolism, protein synthesis, regulatory mechanisms, protein sources, amino acid availability, and autophagy in order to elucidate how these elements collectively maintain cellular homeostasis. We underscore the vital role this dynamic interplay has in preserving cell life.

CONCLUSIONS

A deeper understanding of the link between energy and protein synthesis is essential to comprehend fundamental cellular processes. This insight could have a wide-ranging impact in several medical fields, such as nutrition, metabolism, and disease management.

A review of the pathophysiological mechanisms of doxorubicin-induced cardiotoxicity and aging

The population of cancer survivors is rapidly increasing due to improving healthcare. However, cancer therapies often have long-term side effects. One example is cancer therapy-related cardiac dysfunction (CTRCD) caused by doxorubicin: up to 9% of the cancer patients treated with this drug develop heart failure at a later stage. In recent years, doxorubicin-induced cardiotoxicity has been associated with an accelerated aging phenotype and cellular senescence in the heart. In this review we explain the evidence of an accelerated aging phenotype in the doxorubicin-treated heart by comparing it to healthy aged hearts, and shed light on treatment strategies that are proposed in pre-clinical settings. We will discuss the accelerated aging phenotype and the impact it could have in the clinic and future research.

Ginsenoside Rb2 improves heart failure by down-regulating miR-216a-5p to promote autophagy and inhibit apoptosis and oxidative stress

BACKGROUND

Ginsenoside Rb2 is beneficial in cardiovascular disease treatment, yet its role in heart failure (HF) is obscure. This study aimed to investigate the effect and mechanism of ginsenoside Rb2 on HF.

METHODS

The left anterior descending branch-ligated HF rat model and oxygen-glucose deprivation/reoxygenation (OGD/R) H9c2 cell model were constructed. Ginsenoside Rb2 were applied for intervention. Heart function indexes, miR-216a-5p expression, autophagy, oxidative stress, apoptosis, cell morphology, and proliferation were detected to explore the effect of ginsenoside Rb2 on HF. Overexpression of miR-216a-5p was employed to explore the specific mechanism of ginsenoside Rb2 on HF.

RESULTS

Ginsenoside Rb2 improved the heart function of HF rats, including the reduction of heart rate, LVEDP, and heart weight/body weight ratio, and the increase of LVSP, +dP/dtmax, -dP/dtmax, LVEF, and LVFS. It also down-regulated miR-216a-5p expression and enhanced OGD/R-induced cardiomyocyte viability. Ginsenoside Rb2 up-regulated Bcl2, LC3B II/I, and Beclin1, and down-regulated Bax, Caspase-3, and p62 in the myocardium of HF rats and OGD/R-induced H9c2 cells. Moreover, ginsenoside Rb2 increased the levels of SOD and CAT, but decreased the levels of MDA and ROS in the myocardium of HF rats and OGD/R-induced H9c2 cells. However, overexpression of miR-216a-5p promoted the apoptosis and oxidative stress of cardiomyocytes and inhibited autophagy, thus reversing the therapeutic effect of ginsenoside Rb2 on HF in vivo and in vitro.

CONCLUSION

Ginsenoside Rb2 demonstrated potential as a therapeutic intervention for HF by enhancing autophagy and reducing apoptosis and oxidative stress through miR-216a-5p downregulation. Further research could explore its application in clinical trials and investigate the complex mechanism networks underlying its effects.

Is Intrinsic Cardioprotection a Laboratory Phenomenon or a Clinically Relevant Tool to Salvage the Failing Heart?

Cardiovascular diseases, especially ischemic heart disease, as a leading cause of heart failure (HF) and mortality, will not reduce over the coming decades despite the progress in pharmacotherapy, interventional cardiology, and surgery. Although patients surviving acute myocardial infarction live longer, alteration of heart function will later lead to HF. Its rising incidence represents a danger, especially among the elderly, with data showing more unfavorable results among females than among males. Experiments revealed an infarct-sparing effect of ischemic "preconditioning" (IPC) as the most robust form of innate cardioprotection based on the heart's adaptation to moderate stress, increasing its resistance to severe insults. However, translation to clinical practice is limited by technical requirements and limited time. Novel forms of adaptive interventions, such as "remote" IPC, have already been applied in patients, albeit with different effectiveness. Cardiac ischemic tolerance can also be increased by other noninvasive approaches, such as adaptation to hypoxia- or exercise-induced preconditioning. Although their molecular mechanisms are not yet fully understood, some noninvasive modalities appear to be promising novel strategies for fighting HF through targeting its numerous mechanisms. In this review, we will discuss the molecular mechanisms of heart injury and repair, as well as interventions that have potential to be used in the treatment of patients.

miRNA-103-3p-Hlf regulates apoptosis and autophagy by targeting hepatic leukaemia factor in heart failure

AIMS

Cardiomyocyte apoptosis is an important factor leading to the occurrence and development of heart failure (HF), which is associated with high mortality of patients with cardiovascular diseases. This study aims to investigate the underlying mechanisms of HF in terms of expression and regulation patterns using bioinformatics and experimental validation.

METHODS AND RESULTS

Two HF datasets were collected: a dataset GSE112056 downloaded from the GEO database (including mRNA and miRNA sequencing data) and another is the laboratory-owned mRNA dataset. Differential mRNAs and miRNAs in the two datasets were screened using the raw Bayesian approach method. Gene Ontology was used to perform functional enrichment analysis of the differential mRNAs and co-expression network analysis of the differential mRNAs, combined with nuclear transcription factors in the differential miRNAs and mRNAs for target gene prediction. A HF cell model was constructed using mouse cardiomyocytes (HL-1), and the role and mechanism of miRNA-103-3p-Hlf (hepatic leukaemia factor) in the process of HF was verified by cell transfection, luciferase reporter gene, WB, and qPCR. We found that Hlf gene expression was decreased in the HF model group and strongly correlated with FYCO1 (FYVE and coiled-coil domain-containing protein 1) gene, a phenomenon enriched in apoptotic autophagy-related pathways. MiR-103-3p expression was up-regulated in the HF model group, and its targeting correlation with Hlf was confirmed by luciferase activity assay. In the HL-1 cell model, miR-103-3p significantly promoted apoptosis and inhibited autophagy in HL-1 cells (all P < 0.05), and overexpression of the Hlf gene reversed this phenomenon, inhibiting apoptosis and promoting autophagy in HL-1 cells (all P < 0.05).

CONCLUSIONS

MiR-103-3p affects myocardial cells apoptosis and autophagy by targeting Hlf, playing as a potential therapeutic biomarker for HF progression.

S100a9 inhibits Atg9a transcription and participates in suppression of autophagy in cardiomyocytes induced by β1-adrenoceptor autoantibodies

BACKGROUND

Cardiomyocyte death induced by autophagy inhibition is an important cause of cardiac dysfunction. In-depth exploration of its mechanism may help to improve cardiac dysfunction. In our previous study, we found that β1-adrenergic receptor autoantibodies (β1-AAs) induced a decrease in myocardial autophagy and caused cardiomyocyte death, thus resulting in cardiac dysfunction. Through tandem mass tag (TMT)-based quantitative proteomics, autophagy-related S100a9 protein was found to be significantly upregulated in the myocardial tissue of actively immunized mice. However, whether S100a9 affects the cardiac function in the presence of β1-AAs through autophagy and the specific mechanism are currently unclear.

METHODS

In this study, the active immunity method was used to establish a β1-AA-induced mouse cardiac dysfunction model, and RT-PCR and western blot were used to detect changes in gene and protein expression in cardiomyocytes. We used siRNA to knockdown S100a9 in cardiomyocytes. An autophagy PCR array was performed to screen differentially expressed autophagy-related genes in cells transfected with S100a9 siRNA and negative control siRNA. Cytoplasmic nuclear separation, co-immunoprecipitation (Co-IP), and immunofluorescence were used to detect the binding of S100a9 and hypoxia inducible factor-1α (HIF-1α). Finally, AAV9-S100a9-RNAi was injected into mice via the tail vein to knockdown S100a9 in cardiomyocytes. Cardiac function was detected via ultrasonography.

RESULTS

The results showed that β1-AAs induced S100a9 expression. The PCR array indicated that Atg9a changed significantly in S100a9siRNA cells and that β1-AAs increased the binding of S100a9 and HIF-1α in cytoplasm. Knockdown of S100a9 significantly improved autophagy levels and cardiac dysfunction.

CONCLUSION

Our research showed that β1-AAs increased S100a9 expression in cardiomyocytes and that S100a9 interacted with HIF-1α, which prevented HIF-1α from entering the nucleus normally, thus inhibiting the transcription of Atg9a. This resulted in autophagy inhibition and cardiac dysfunction.

Ubiquitin, p62, and Microtubule-Associated Protein 1 Light Chain 3 in Cardiomyopathy

Background: The accumulation of ubiquitinated proteins has been detected in diseased hearts and has been associated with the expression of p62 and microtubule-associated protein 1 light chain 3 (LC3), which are related to autophagy. We evaluated differences in ubiquitin accumulation and p62 and LC3 expression in cardiomyopathy using endomyocardial biopsies. Methods and Results: We studied 24 patients (aged 24-70 years; mean age 55 years) diagnosed with dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), or non-cardiomyopathy (NCM) who underwent endomyocardial biopsy. Biopsied samples were evaluated by microscopy for ubiquitin accumulation and expression of p62 and LC3. Ubiquitin accumulation and p62 and LC3 expression were observed in all patients. Ubiquitin accumulation was higher in DCM than in HCM or NCM; p62 expression was higher in DCM than in HCM. There were no significant differences in LC3 expression among the groups. Ubiquitin accumulation was significantly related to serum N-terminal pro B-type natriuretic peptide concentration and the expression of p62, but not LC3. Conclusions: Ubiquitin accumulation was more prominent in DCM than in HCM and NCM, which may be due to a relative shortage of clearance, including autophagy, compared with production.

SMOC2 plays a role in heart failure via regulating TGF-β1/Smad3 pathway-mediated autophagy

Heart failure (HF) is a major global cause of morbidity and mortality. This study aimed to elucidate the role of secreted protein acidic and rich in cysteine-related modular calcium-binding protein 2 (SMOC2) in HF development and its underlying mechanism. Using a rat HF model, SMOC2 expression was examined and then knocked down via transfection to assess its impact on cardiac function and damage. The study also evaluated the effects of SMOC2 knockdown on autophagy-related molecules and the transforming growth factor beta 1 (TGF-β1)/SMAD family member 3 (Smad3) signaling pathway. Intraperitoneal injection of the TGF-β agonist (SRI-011381) into the HF rat model was performed to explore the SMOC2-TGF-β1/Smad3 pathway relationship. SMOC2 expression was elevated in HF rats, while its downregulation improved cardiac function and damage. SMOC2 knockdown reversed alterations in the LC3-II/I ratio, Beclin-1, and p62 levels in HF rats. Through transmission electron microscope, we observed that SMOC2 knockdown restored autophagosome levels. Furthermore, SMOC2 downregulation inhibited the TGF-β1/Smad3 signaling pathway, which was counteracted by SRI-011381. In conclusion, SMOC2 knockdown inhibits HF development by modulating TGF-β1/Smad3 signaling-mediated autophagy, suggesting its potential as a therapeutic target for HF.

Essential Amino Acids-Rich Diet Increases Cardiomyocytes Protection in Doxorubicin-Treated Mice

BACKGROUND

Doxorubicin (Doxo) is a widely prescribed drug against many malignant cancers. Unfortunately, its utility is limited by its toxicity, in particular a progressive induction of congestive heart failure. Doxo acts primarily as a mitochondrial toxin, with consequent increased production of reactive oxygen species (ROS) and attendant oxidative stress, which drives cardiac dysfunction and cell death. A diet containing a special mixture of all essential amino acids (EAAs) has been shown to increase mitochondriogenesis, and reduce oxidative stress both in skeletal muscle and heart. So, we hypothesized that such a diet could play a favorable role in preventing Doxo-induced cardiomyocyte damage.

METHODS

Using transmission electron microscopy, we evaluated cells' morphology and mitochondria parameters in adult mice. In addition, by immunohistochemistry, we evaluated the expression of pro-survival marker Klotho, as well as markers of necroptosis (RIP1/3), inflammation (TNFα, IL1, NFkB), and defense against oxidative stress (SOD1, glutathione peroxidase, citrate synthase).

RESULTS

Diets with excess essential amino acids (EAAs) increased the expression of Klotho and enhanced anti-oxidative and anti-inflammatory responses, thereby promoting cell survival.

CONCLUSION

Our results further extend the current knowledge about the cardioprotective role of EAAs and provide a novel theoretical basis for their preemptive administration to cancer patients undergoing chemotherapy to alleviate the development and severity of Doxo-induced cardiomyopathy.

Heart Failure And Type 2 Diabetes Mellitus: Neurohumoral, Histological And Molecular Interconnections

Heart failure (HF) is a global healthcare burden and a leading cause of morbidity and mortality worldwide. Type 2 diabetes mellitus (T2DM) appears to be one of the major risk factors that significantly worsen HF prognosis and increase the risk of fatal cardiovascular outcomes. Despite a great knowledge of pathophysiological mechanisms involved in HF development and progression, hospitalization rates in patients with HF and concomitant T2DM remain elevated. In this review, we discuss the complex interplay between systemic neurohumoral regulation and local cardiac mechanisms participating in myocardial remodeling and HF development in T2DM with special attention to cardiomyocyte energy metabolism, mitochondrial function and calcium metabolism, cardiomyocyte hypertrophy and death, extracellular matrix remodeling.

Molecular Mechanisms of Mitochondrial Quality Control in Ischemic Cardiomyopathy

Ischemic cardiomyopathy (ICM) is a special type of coronary heart disease or an advanced stage of the disease, which is related to the pathological mechanism of primary dilated cardiomyopathy. Ischemic cardiomyopathy mainly occurs in the long-term myocardial ischemia, resulting in diffuse myocardial fibrosis. This in turn affects the cardiac ejection function, resulting in a significant impact on myocardial systolic and diastolic function, resulting in a decrease in the cardiac ejection fraction. The pathogenesis of ICM is closely related to coronary heart disease. Mainly due to coronary atherosclerosis caused by coronary stenosis or vascular occlusion, causing vascular inflammatory lesions and thrombosis. As the disease progresses, it leads to long-term myocardial ischemia and eventually ICM. The pathological mechanism is mainly related to the mechanisms of inflammation, myocardial hypertrophy, fibrosis and vascular remodeling. Mitochondria are organelles with a double-membrane structure, so the composition of the mitochondrial outer compartment is basically similar to that of the cytoplasm. When ischemia-reperfusion induces a large influx of calcium into the cell, the concentration of calcium ions in the mitochondrial outer compartment also increases. The subsequent opening of the membrane permeability transition pore in the inner mitochondrial membrane and the resulting calcium overload induces the homeostasis of cardiomyocytes and activates the mitochondrial pathway of apoptosis. Mitochondrial Quality Control (MQC), as an important mechanism for regulating mitochondrial function in cardiomyocytes, affects the morphological structure/function and lifespan of mitochondria. In this review, we discuss the role of MQC (including mitophagy, mitochondrial dynamics, and mitochondrial biosynthesis) in the pathogenesis of ICM and provide important evidence for targeting MQC for ICM.

Tax1 banding protein 1 exacerbates heart failure in mice by activating ITCH-P73-BNIP3-mediated cardiomyocyte apoptosis

Tax1 banding protein 1 (Tax1bp1) was originally identified as an NF-κB regulatory protein that participated in inflammatory, antiviral and innate immune processes. Tax1bp1 also functions as an autophagy receptor that plays a role in autophagy. Our previous study shows that Tax1bp1 protects against cardiomyopathy in STZ-induced diabetic mice. In this study we investigated the role of Tax1bp1 in heart failure. Pressure overload-induced heart failure model was established in mice by aortic banding (AB) surgery, and angiotensin II (Ang II)-induced heart failure model was established by infusion of Ang II through osmotic minipump for 4 weeks. We showed that the expression levels of Tax1bp1 in the heart were markedly increased 2 and 4 weeks after AB surgery. Knockdown of Tax1bp1 in mouse hearts significantly ameliorated both AB- and Ang II infusion-induced heart failure parameters. On the contrary, AB-induced heart failure was aggravated in cardiac-specific Tax1bp1 transgenic mice. Similar results were observed in neonatal rat cardiomyocytes (NRCMs) under Ang II insult. We demonstrated that the pro-heart failure effect of Tax1bp1 resulted from its interaction with the E3 ligase ITCH to promote the transcription factor P73 ubiquitination and degradation, causing enhanced BCL2 interacting protein 3 (BNIP3)-mediated cardiomyocyte apoptosis. Knockdown ITCH or BNIP3 in NRCMs significantly reduced Ang II-induced apoptosis in vitro. Similarly, BNIP3 knockdown attenuated heart failure in cardiac-specific Tax1bp1 transgenic mice. In the left ventricles of heart failure patients, Tax1bp1 expression level was significantly increased; Tax1bp1 gene expression was negatively correlated with left ventricular ejection fraction in heart failure patients. Collectively, the Tax1bp1 increase in heart failure enhances ITCH-P73-BNIP3-mediated cardiomyocyte apoptosis and induced cardiac injury. Tax1bp1 may serve as a potent therapeutic target for the treatment of heart failure.• Cardiac Tax1bp1 transgene mice were more vulnerable to cardiac dysfunction under stress.• Cardiac Tax1bp1 transgene mice were more vulnerable to cardiac dysfunction under stress.• Knockout of Tax1bp1 in mouse hearts ameliorated heart failure induced by pressure overload.• Tax1bp1 interacts with the E3 ligase Itch to promote P73 ubiquitination and degradation, causing enhanced BNIP3-mediated apoptosis.• Tax1bp1 may become a target of new therapeutic methods for treating heart failure.

Analysis of necroptosis and its association with pyroptosis in organ damage in experimental pulmonary arterial hypertension

In this study, a role of cell loss due to necroptosis and its linkage with pyroptosis in organ damage under the conditions of pulmonary arterial hypertension (PAH) was examined. Monocrotaline (MCT) was used to induce PAH in Wistar rats, and depending on the severity of the disease progression, they were further divided into two subgroups: MCT group-sacrificed 4 weeks after MCT administration and ptMCT group-prematurely sacrificed due to rapid deterioration in vital functions (on Day 24,11 ± 0,7). The elevation of respiratory rate and right ventricular (RV) hypertrophy were more evident in ptMCT group, while the heart rate and cardiac haemodynamic stress markers were comparably higher in both diseased groups. Detailed immunoblotting analysis revealed that the upregulation of pThr²³¹ /Ser²³² -RIP3 proceeded into necroptosis execution in the RVs, unlike in the lungs of both PAH stages. The elevated pulmonary pThr²³¹ /Ser²³² -RIP3 levels in both PAH subgroups were associated rather with GSDMD-mediated pyroptosis. On the contrary, other inflammasome forms, such as AIM2 and NLRC4, were higher in the RV, unlike in the lungs, of diseased groups. The PAH-induced increase in the plasma RIP3 levels was more pronounced in ptMCT group, and positively correlated with RV hypertrophy, but not with haemodynamic stress. Taken together, we indicated for the first time that pThr²³¹ /Ser²³² -RIP3 upregulation resulting in two different necrosis-like cell death modes might underlie the pathomechanisms of PAH and that the plasma RIP3 might serve as an additional diagnostic and prognostic marker of cardiac injury under these conditions.

Interactions of circRNAs with methylation: An important aspect of circRNA biogenesis and function (Review)

Circular RNA (circRNA) molecules are noncoding RNAs with unique circular covalently closed structures that contribute to gene expression regulation, protein translation and act as microRNA sponges. circRNAs also have important roles in human disease, particularly tumorigenesis and antitumor processes. Methylation is an epigenetic modification that regulates the expression and roles of DNA and coding RNA and their interactions, as well as of noncoding RNA molecules. Previous studies have focused on the effects of methylation modification on circRNA expression, transport, stability, translation and degradation of circRNAs, as well as how circRNA methylation occurs and the influence of circRNAs on methylation modification processes. circRNA and methylation can also regulate disease pathogenesis via these interactions. In the present study, we define the relationship between circRNAs and methylation, as well as the functions and mechanisms of their interactions during disease progression.

The role of autophagy in cardiovascular pathology

Macroautophagy/autophagy is a conserved catabolic recycling pathway in which cytoplasmic components are sequestered, degraded, and recycled to survive various stress conditions. Autophagy dysregulation has been observed and linked with the development and progression of several pathologies, including cardiovascular diseases, the leading cause of death in the developed world. In this review, we aim to provide a broad understanding of the different molecular factors that govern autophagy regulation and how these mechanisms are involved in the development of specific cardiovascular pathologies, including ischemic and reperfusion injury, myocardial infarction, cardiac hypertrophy, cardiac remodelling, and heart failure.

Main active components of Si-Miao-Yong-An decoction (SMYAD) attenuate autophagy and apoptosis via the PDE5A-AKT and TLR4-NOX4 pathways in isoproterenol (ISO)-induced heart failure models

Heart failure (HF), the main cause of death in patients with many cardiovascular diseases, has been reported to be closely related to the complicated pathogenesis of autophagy, apoptosis, and inflammation. Notably, Si-Miao-Yong-An decoction (SMYAD) is a traditional Chinese medicine (TCM) used to treat cardiovascular disease; however, the main active components and their relevant mechanisms remain to be discovered. Based on our previous ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) results, we identified angoriside C (AC) and 3,5-dicaffeoylquinic acid (3,5-DiCQA) as the main active components of SMYAD. In vivo results showed that AC and 3,5-DiCQA effectively improved cardiac function, reduced the fibrotic area, and alleviated isoproterenol (ISO)-induced myocarditis in rats. Moreover, AC and 3,5-DiCQA inhibited ISO-induced autophagic cell death by inhibiting the PDE5A/AKT/mTOR/ULK1 pathway and inhibited ISO-induced apoptosis by inhibiting the TLR4/NOX4/BAX pathway. In addition, the autophagy inhibitor 3-MA was shown to reduce ISO-induced apoptosis, indicating that ISO-induced autophagic cell death leads to excess apoptosis. Taken together, the main active components AC and 3,5-DiCQA of SMYAD inhibit the excessive autophagic cell death and apoptosis induced by ISO by inhibiting the PDE5A-AKT and TLR4-NOX4 pathways, thereby reducing myocardial inflammation and improving heart function to alleviate and treat a rat ISO-induced heart failure model and cell heart failure models. More importantly, the main active components of SMYAD will provide new insights into a promising strategy that will promote the discovery of more main active components of SMYAD for therapeutic purposes in the future.

Impact of Oxysterols on Cell Death, Proliferation, and Differentiation Induction: Current Status

Oxysterols are oxidized derivatives of cholesterol produced by enzymatic activity or non-enzymatic pathways (auto-oxidation). The oxidation processes lead to the synthesis of about 60 different oxysterols. Several oxysterols have physiological, pathophysiological, and pharmacological activities. The effects of oxysterols on cell death processes, especially apoptosis, autophagy, necrosis, and oxiapoptophagy, as well as their action on cell proliferation, are reviewed here. These effects, also observed in several cancer cell lines, could potentially be useful in cancer treatment. The effects of oxysterols on cell differentiation are also described. Among them, the properties of stimulating the osteogenic differentiation of mesenchymal stem cells while inhibiting adipogenic differentiation may be useful in regenerative medicine.

Enhanced oxidative stress mediates pathological autophagy and necroptosis in cardiac myocytes in pressure overload induced heart failure in rats

In cardiac myocytes in vitro, hydrogen peroxide induces autophagic cell death and necroptosis. Oxidative stress, myocyte autophagy and necroptosis coexist in heart failure (HF). In this study, we tested the hypothesis that excessive oxidative stress mediates pathological autophagy and necroptosis in myocytes in pressure overload-induced HF. HF was produced by chronic pressure overload induced by abdominal aortic constriction (AAC) in rats. Rats with AAC or sham operation were randomised to orally receive an antioxidant N-acetylcysteine (NAC) or placebo for 4 weeks. Echocardiography was performed for the assessments of left ventricular (LV) structure and function. AAC rats exhibited decreased LV fractional shortening (FS) at 4 weeks after surgery. NAC treatment attenuated decreased LV FS in AAC rats. In AAC rats, myocardial level of 8-hydroxydeoxyguanosine assessed by immunohistochemical staining, indicative of oxidative stress, was increased, LC3 II protein, a marker of autophagy, Beclin1 protein and Atg4b, Atg5, Atg7 and Atg12 mRNA expression were markedly increased, RIP1, RIP3 and MLKL expression, indicative of necroptosis, was increased, and all of the alterations in AAC rats were prevented by the NAC treatment. NAC treatment also attenuated myocyte cross-sectional area and myocardial fibrosis in AAC rats. In conclusion, NAC treatment prevented the increases in oxidative stress, myocyte autophagy and necroptosis and the decrease in LV systolic function in pressure overload-induced HF. These findings suggest that enhanced oxidative stress mediates pathological autophagy and necroptosis in myocytes, leading to LV systolic dysfunction, and antioxidants may be of value to prevent HF through the inhibition of excessive autophagy and necroptosis.

RhoA Signaling in Immune Cell Response and Cardiac Disease

Chronic inflammation, the activation of immune cells and their cross-talk with cardiomyocytes in the pathogenesis and progression of heart diseases has long been overlooked. However, with the latest research developments, it is increasingly accepted that a vicious cycle exists where cardiomyocytes release cardiocrine signaling molecules that spiral down to immune cell activation and chronic state of low-level inflammation. For example, cardiocrine molecules released from injured or stressed cardiomyocytes can stimulate macrophages, dendritic cells, neutrophils and even T-cells, which then subsequently increase cardiac inflammation by co-stimulation and positive feedback loops. One of the key proteins involved in stress-mediated cardiomyocyte signal transduction is a small GTPase RhoA. Importantly, the regulation of RhoA activation is critical for effective immune cell response and is being considered as one of the potential therapeutic targets in many immune-cell-mediated inflammatory diseases. In this review we provide an update on the role of RhoA at the juncture of immune cell activation, inflammation and cardiac disease.

Insight into Crosstalk between Ferroptosis and Necroptosis: Novel Therapeutics in Ischemic Stroke

Ferroptosis is a nonapoptotic form of cell death characterized by iron-dependent accumulation of lipid hydroperoxides to lethal levels. Necroptosis, an alternative form of programmed necrosis, is regulated by receptor-interacting protein (RIP) 1 activation and by RIP3 and mixed-lineage kinase domain-like (MLKL) phosphorylation. Ferroptosis and necroptosis both play important roles in the pathological progress in ischemic stroke, which is a complex brain disease regulated by several cell death pathways. In the past few years, increasing evidence has suggested that the crosstalk occurs between necroptosis and ferroptosis in ischemic stroke. However, the potential links between ferroptosis and necroptosis in ischemic stroke have not been elucidated yet. Hence, in this review, we overview and analyze the mechanism underlying the crosstalk between necroptosis and ferroptosis in ischemic stroke. And we find that iron overload, one mechanism of ferroptosis, leads to mitochondrial permeability transition pore (MPTP) opening, which aggravates RIP1 phosphorylation and contributes to necroptosis. In addition, heat shock protein 90 (HSP90) induces necroptosis and ferroptosis by promoting RIP1 phosphorylation and suppressing glutathione peroxidase 4 (GPX4) activation. In this work, we try to deliver a new perspective in the exploration of novel therapeutic targets for the treatment of ischemic stroke.

Effects of Hsp90 inhibitor on the RIP1-RIP3-MLKL pathway during the development of heart failure in mice

Necroptosis is a programmed form of necrotic cell death. Necroptosis is regulated by the necroptosis-regulating proteins including receptor-interacting protein (RIP) 1, RIP3, and mixed lineage kinase domain-like (MLKL), the activities of which are modulated by the molecular chaperone heat-shock protein (Hsp) 90. Presently, to clarify the relationship between Hsp90 and necroptotic pathway proteins, RIP1, RIP3, and MLKL in the development of heart failure, we examined the effects of Hsp90 inhibitor treatment on the RIP1-RIP3-MLKL pathway in mice following transverse aortic constriction (TAC). In this study, TAC mice showed typical signs of heart failure at the 8th week after the operation. In the failing heart, the levels of these regulatory proteins and those of their phosphorylated forms were increased, suggesting that necroptosis contributed to the development of heart failure in the TAC mice. The increases in RIP1, RIP3, and MLKL after TAC were reversed by the administration of an Hsp90 inhibitor. Furthermore, the rise in the phosphorylation levels of these 3 proteins were attenuated by the Hsp90 inhibitor. Concomitantly, cardiac functions were preserved. We also found that exposure of cultured adult mouse cardiomyocytes to the Hsp90 inhibitor attenuated necrotic cell death induced by tumor necrosis factor-α via suppression of RIP1, RIP3, and MLKL activation in in vitro experiments. Taken together, our findings suggest that inhibition of Hsp90 should have therapeutic effects by reducing the activation of RIP1-RIP3-MLKL pathway in the hypertrophied heart and thus could be a new therapeutic strategy for chronic heart failure.

Targeting necroptosis as therapeutic potential in chronic myocardial infarction

Cardiovascular diseases (CVDs) are considered the predominant cause of morbidity and mortality globally. Of these, myocardial infarction (MI) is the most common cause of CVD mortality. MI is a life-threatening condition which occurs when coronary perfusion is interrupted leading to cardiomyocyte death. Subsequent to MI, consequences include adverse cardiac remodeling and cardiac dysfunction mainly contribute to the development of heart failure (HF). It has been shown that loss of functional cardiomyocytes in MI-induced HF are associated with several cell death pathways, in particular necroptosis. Although the entire mechanism underlying necroptosis in MI progression is still not widely recognized, some recent studies have reported beneficial effects of necroptosis inhibitors on cell viability and cardiac function in chronic MI models. Therefore, extensive investigation into the necroptosis signaling pathway is indicated for further study. This article comprehensively reviews the context of the underlying mechanisms of necroptosis in chronic MI-induced HF in in vitro, in vivo and clinical studies. These findings could inform ways of developing novel therapeutic strategies to improve the clinical outcomes in MI patients from this point forward.

How Can Malnutrition Affect Autophagy in Chronic Heart Failure? Focus and Perspectives

Chronic heart failure (CHF) is a disease with important clinical and socio-economic ramifications. Malnutrition and severe alteration of the protein components of the body (protein disarrangements), common conditions in CHF patients, are independent correlates of heart dysfunction, disease progression, and mortality. Autophagy, a prominent occurrence in the heart of patients with advanced CHF, is a self-digestive process that prolongs myocardial cell lifespan by the removal of cytosolic components, such as aging organelles and proteins, and recycles the constituent elements for new protein synthesis. However, in specific conditions, excessive activation of autophagy can lead to the destruction of molecules and organelles essential to cell survival, ultimately leading to organ failure and patient death. In this review, we aim to describe the experimental and clinical evidence supporting a pathophysiological role of nutrition and autophagy in the progression of CHF. The understanding of the mechanisms underlying the interplay between nutrition and autophagy may have important clinical implications by providing molecular targets for innovative therapeutic strategies in CHF patients.

The Potential of Hydrogen Sulfide Donors in Treating Cardiovascular Diseases

Hydrogen sulfide (H2S) has long been considered as a toxic gas, but as research progressed, the idea has been updated and it has now been shown to have potent protective effects at reasonable concentrations. H2S is an endogenous gas signaling molecule in mammals and is produced by specific enzymes in different cell types. An increasing number of studies indicate that H2S plays an important role in cardiovascular homeostasis, and in most cases, H2S has been reported to be downregulated in cardiovascular diseases (CVDs). Similarly, in preclinical studies, H2S has been shown to prevent CVDs and improve heart function after heart failure. Recently, many H2S donors have been synthesized and tested in cellular and animal models. Moreover, numerous molecular mechanisms have been proposed to demonstrate the effects of these donors. In this review, we will provide an update on the role of H2S in cardiovascular activities and its involvement in pathological states, with a special focus on the roles of exogenous H2S in cardiac protection.

Management of Anaemia of Chronic Disease: Beyond Iron-Only Supplementation

Chronic diseases are characterised by altered autophagy and protein metabolism disarrangement, resulting in sarcopenia, hypoalbuminemia and hypo-haemoglobinaemia. Hypo-haemoglobinaemia is linked to a worse prognosis independent of the target organ affected by the disease. Currently, the cornerstone of the therapy of anaemia is iron supplementation, with or without erythropoietin for the stimulation of haematopoiesis. However, treatment strategies should incorporate the promotion of the synthesis of heme, the principal constituent of haemoglobin (Hb) and of many other fundamental enzymes for human metabolism. Heme synthesis is controlled by a complex biochemical pathway. The limiting step of heme synthesis is D-amino-levulinic acid (D-ALA), whose availability and synthesis require glycine and succinil-coenzyme A (CoA) as precursor substrates. Consequently, the treatment of anaemia should not be based only on the sufficiency of iron but, also, on the availability of all precursor molecules fundamental for heme synthesis. Therefore, an adequate clinical therapeutic strategy should integrate a standard iron infusion and a supply of essential amino acids and vitamins involved in heme synthesis. We reported preliminary data in a select population of aged anaemic patients affected by congestive heart failure (CHF) and catabolic disarrangement, who, in addition to the standard iron therapy, were treated by reinforced therapeutic schedules also providing essential animo acids (AAs) and vitamins involved in the maintenance of heme. Notably, such individualised therapy resulted in a significantly faster increase in the blood concentration of haemoglobin after 30 days of treatment when compared to the nonsupplemented standard iron therapy.

Programmed Cell Death in the Left and Right Ventricle of the Late Phase of Post-Infarction Heart Failure

While necroptosis has been shown to contribute to the pathogenesis of post-infarction heart failure (HF), the role of autophagy remains unclear. Likewise, linkage between these two cell death modalities has not been sufficiently investigated. HF was induced by 60-min left coronary occlusion in adult Wistar rats and heart function was assessed 6 weeks later followed by immunoblotting analysis of necroptotic and autophagic proteins in both the left (LV) and right ventricle (RV). HF had no effect on RIP1 and RIP3 expression. PhosphoSer229-RIP3, acting as a pro-necroptotic signal, was increased in LV while deceased in RV of failing hearts. Total MLKL was elevated in RV only. Decrease in pSer555-ULK1, increase in pSer473-Akt and no significant elevation in beclin-1 and LC3-II/I ratio indicated rather a lowered rate of autophagy in LV. No beclin-1 upregulation and decreased LC3 processing also suggested the inhibition of both autophagosome formation and maturation in RV of failing hearts. In contrast, p89 PARP1 fragment, a marker of executed apoptosis, was increased in RV only. This is the first study showing a different signaling in ventricles of the late phase of post-infarction HF, highlighting necroptosis itself rather than its linkage with autophagy in LV, and apoptosis in RV.

Endoplasmic Reticulum Stress Regulates Cardiomyocyte Apoptosis in Myocardial Fibrosis Development via PERK-Mediated Autophagy

Endoplasmic reticulum stress (ERS) is involved in a variety of diseases. Recently, it was found that ERS induces not only apoptosis but also autophagy. Previous studies showed that inhibition of autophagy alleviates cell injury. The purpose of our study was to investigate the involvement of the R-like ER kinase (PERK) in ERS-induced autophagy in H9c2 cardiomyoblasts. To address this aim, therefore, H9c2 cells were treated with PERK agonist and inhibitor after establishment of rapamycin-induced ERS models in H9c2 cardiomyoblasts. Transmission electron microscopy and immunofluorescence staining were used to detect degrees of ERS-induced autophagy, apoptosis and myocardial fibrosis. Western blotting was employed to detect the levels of total and phosphorylated PERK, light chain 3 (LC3), P62, Caspase3, Bcl2 and Bax. Immunofluorescence staining was used to assess α-SMA density. TGF-β induced H9c2 cardiomyoblasts time-dependently upregulated col I, col III, FN, and LC3 expressions, PERK phosphorylation and α-SMA density, and downregulated P62 level compared with control cells. Treatment with PERK agonist and inhibitor respectively increased and decreased LC3 expression, conversely in P62 level, which is consistent with effect of ERS agonists and inhibitors. And a PERK inhibitor upregulated the expressions of Caspase3 and Bax, and downregulated Bcl2 level, which developed H9c2 cardiomyoblasts. Moreover, siRNA-mediated knockdown of PERK reduced ERS mediated autophagy activity and increased cells apoptosis. On the other hand, elevated autophagy activity could downregulated PERK level. Our finding showed that PERK activity mediates upregulation of ERS-induced autophagy and regulation of cardiomyocyte apoptosis in H9c2 cardiomyoblasts.

Plasma concentration of receptor-interacting protein kinase-3 as a potential biomarker for diagnosis and prognosis in heart failure

BACKGROUND

Receptor-interacting serine-threonine kinase 3 (RIP3) is a key mediator of programmed necrosis (necroptosis), and is implicated in cardiac remodeling and heart failure (HF) triggered by ischemia-reperfusion or oxidative stress in animal study. However, its value in the diagnosis and prognosis of human HF remains unclear.

METHODS

Plasma RIP3 concentrations in 91 HF patients and 95 healthy volunteers were detected by enzyme-linked immunosorbent assay (ELISA). A receiver operating characteristic (ROC) curve was generated to evaluate the diagnostic value of RIP3. Follow-up was conducted, and the composite endpoint was defined as all-cause mortality/readmission due to decompensated HF/worse New York Heart Association (NYHA) functional class. The relationship between RIP3 and patient outcome was examined.

RESULTS

Plasma concentrations of RIP3 were significantly increased in patients with HF compared to controls (P < 0.001). ROC analysis supported plasma RIP3 as a good diagnostic marker for HF, with an optimal cutoff value of 357 pg/ml (AUC = 0.934, sensitivity = 0.846, specificity = 0.905). Kaplan-Meier survival analysis also supported increased plasma RIP3 as a predictor for a poor prognosis in HF (cutoff value = 622.2 pg/ml, P < 0.05). Additionally, binary logistic regression analysis revealed RIP3 to be an independent risk factor for all-cause mortality (OR = 11.844, P = 0.02), worse NYHA (OR = 9.013, P = 0.009) and a composite endpoint (OR = 5.065, P = 0.013).

CONCLUSIONS

Plasma concentration of RIP3 is significantly elevated in HF and associated with the prognosis. Plasma RIP3 possibly constitutes a valuable diagnostic and prognostic biomarker for HF.

Overexpression of miR-146a inhibits the apoptosis of hippocampal neurons of rats with cerebral hemorrhage by regulating autophagy

In this study, to investigate the effect of overexpression of miR-146a on autophagy of hippocampal neurons in rats with intracerebral hemorrhage (ICH), 72 Sprague-Dawley rats were randomly divided into the sham, ICH, miR-146a agomir, and miR-146a agomir control groups. The ICH model was constructed by injection of collagenase VII. The apoptosis of hippocampal neurons was measured by TUNEL assay. The levels of LC3 and Beclin 1 were analyzed by immunohistochemistry. Mitochondrial autophagy was examined by transmission electron microscopy. The levels of LC3A, LC3B, Beclin 1, Bax, Bcl-2, and cleaved caspase 3 were examined by Western blot. Western blot was also used to evaluate the expression of nuclear factor κB signaling pathway-related factors. To examine the effect of autophagy inhibitor (3-methyladenine (3-MA)) on miR-146a-regulated apoptotic protein expression, 30 rats were further divided into the sham, ICH, miR-146a agomir, 3-MA, and miR-146a + 3-MA groups. The levels of Bax, Bcl-2, and cleaved caspase 3 were examined by Western blot. Compared with the sham group, the nerve function scores, brain water content, the percentage of apoptotic cells, and the expression levels of LC3, Beclin 1, Bax, cleaved caspase 3, and p-P65 in the hippocampus of rats in the ICH group were all significantly increased (p < 0.05), whereas the expression levels of miR-146a, Bcl-2, and p-IκBα were markedly decreased (p < 0.05). Mitochondrial autophagy was also evident. Furthermore, compared with the ICH group, the results of the abovementioned tests in the miR-146a agomir group were reversed. The overexpression of miR-146a inhibited the autophagy of hippocampal neurons in rats with ICH.

Cellular and Molecular Differences between HFpEF and HFrEF: A Step Ahead in an Improved Pathological Understanding

Heart failure (HF) is the most rapidly growing cardiovascular health burden worldwide. HF can be classified into three groups based on the percentage of the ejection fraction (EF): heart failure with reduced EF (HFrEF), heart failure with mid-range-also called mildly reduced EF- (HFmrEF), and heart failure with preserved ejection fraction (HFpEF). HFmrEF can progress into either HFrEF or HFpEF, but its phenotype is dominated by coronary artery disease, as in HFrEF. HFrEF and HFpEF present with differences in both the development and progression of the disease secondary to changes at the cellular and molecular level. While recent medical advances have resulted in efficient and specific treatments for HFrEF, these treatments lack efficacy for HFpEF management. These differential response rates, coupled to increasing rates of HF, highlight the significant need to understand the unique pathogenesis of HFrEF and HFpEF. In this review, we summarize the differences in pathological development of HFrEF and HFpEF, focussing on disease-specific aspects of inflammation and endothelial function, cardiomyocyte hypertrophy and death, alterations in the giant spring titin, and fibrosis. We highlight the areas of difference between the two diseases with the aim of guiding research efforts for novel therapeutics in HFrEF and HFpEF.

Dexrazoxane ameliorates doxorubicin-induced cardiotoxicity by inhibiting both apoptosis and necroptosis in cardiomyocytes

Doxorubicin, as a first line chemotherapeutic agent, its usage is limited owing to cardiotoxicity. Necroptosis is a new form of programmed cell death, and recent investigations indicated that necroptosis is vitally involved in serious cardiac pathological conditions. Dexrazoxane is the only cardiac protective drug approved by FDA for anthracycline. We aimed to explore whether and how dexrazoxane regulates doxorubicin-induced cardiomyocyte necroptosis. First, doxorubicin could cause heart failure and reduce cardiomyocyte viability by promoting cell apoptosis and necroptosis in vivo and in vitro. Second, necroptosis plays an important role in doxorubicin induced cardiomyocyte injury, which could be inhibited by Nec-1. Third, dexrazoxane increased cell viability and protect heart function by decreasing both cardiomyocyte apoptosis and necroptosis after doxorubicin treatment. Forth, dexrazoxane attenuated doxorubicin-induced inflammation and necroptosis by the inhibition of p38MAPK/NF-κB pathways. These results indicated that dexrazoxane ameliorates cardiotoxicity and protects heart function by attenuating both apoptosis and necroptosis in doxorubicin induced cardiomyocyte injury.

7-Ketocholesterol Promotes Oxiapoptophagy in Bone Marrow Mesenchymal Stem Cell from Patients with Acute Myeloid Leukemia

7-Ketocholesterol (7-KC) is a cholesterol oxidation product with several biological functions. 7-KC has the capacity to cause cell death depending on the concentration and specific cell type. Mesenchymal stem cells (MSCs) are multipotent cells with the ability to differentiate into various types of cells, such as osteoblasts and adipocytes, among others. MSCs contribute to the development of a suitable niche for hematopoietic stem cells, and are involved in the development of diseases, such as leukemia, to a yet unknown extent. Here, we describe the effect of 7-KC on the death of bone marrow MSCs from patients with acute myeloid leukemia (LMSCs). LMSCs were less susceptible to the death-promoting effect of 7-KC than other cell types. 7-KC exposure triggered the extrinsic pathway of apoptosis with an increase in activated caspase-8 and caspase-3 activity. Mechanisms other than caspase-dependent pathways were involved. 7-KC increased ROS generation by LMSCs, which was related to decreased cell viability. 7-KC also led to disruption of the cytoskeleton of LMSCs, increased the number of cells in S phase, and decreased the number of cells in the G1/S transition. Autophagosome accumulation was also observed. 7-KC downregulated the SHh protein in LMSCs but did not change the expression of SMO. In conclusion, oxiapoptophagy (OXIdative stress + APOPTOsis + autophagy) seems to be activated by 7-KC in LMSCs. More studies are needed to better understand the role of 7-KC in the death of LMSCs and the possible effects on the SHh pathway.