Epidermal growth factor protects the heart against low-flow ischemia-induced injury

Mechanism of Nardostachyos Radix et Rhizoma-Salidroside in the treatment of premature ventricular beats based on network pharmacology and molecular docking

To analyse the mechanism of Nardostachyos Radix et Rhizoma-Salidroside in the treatment of Premature Ventricular Brats by using network pharmacology and molecular docking and to provide the basis for developing the use of experimental and clinical traditional Chinese medicine. The chemical compositions of Nardostachyos Radix et Rhizoma and Salidroside were determined, and their related targets were predicted. The disease-related targets were obtained by searching the common disease databases Genecards, OMIM, Drugbank and DisGeNET, and the intersection between the predicted targets and the disease targets was determined. Then using the STRING database to set up the protein‒protein interactions (PPIs) network between Nardostachyos Radix et Rhizoma-Salidroside and the common targets of PVB. An "herb-ingredient-target" network was constructed and analyzed by Cytoscape3.7.2 software. Using the metascape database to analysis the predicted therapeutic targets based on the GO and KEGG. Finally, molecular docking technology was used toconfirm the capacity of the primary active ingredients of the 2 herbs to bind to central targets using the online CB-Dock2 database. 41 active components of Nardostachyos Radix et Rhizoma-Salidroside were detected, with 420 potential targets of action, with a total of 1688 PVB targets, and the top 10 core targets of herb-disease degree values were AKT1, TNF, GAPDH, SRC, PPARG, EGFR, PTGS2, ESR1, MMP9, and STAT3. KEGG analysis indicated that its mechanism may be related to the calcium signalling pathway, cancer signalling pathway, AGE-RAGE signalling pathway and other pathways. Molecular docking suggested that main of the active ingredients of the Nardostachyos Radix et Rhizoma-Salidroside pairs were well bound to the core targets. Based on novel network pharmacology and molecular docking validation research methods, we revealed for the first time the potential mechanism of Nardostachyos Radix et Rhizoma-Salidroside in PVB therapy.

Combined genetic and chemical screens indicate protective potential for EGFR inhibition to cardiomyocytes under hypoxia

The return of blood flow to ischemic heart after myocardial infarction causes ischemia-reperfusion injury. There is a clinical need for novel therapeutic targets to treat myocardial ischemia-reperfusion injury. Here we screened for targets for the treatment of ischemia-reperfusion injury using a combination of shRNA and drug library analyses in HL-1 mouse cardiomyocytes subjected to hypoxia and reoxygenation. The shRNA library included lentiviral constructs targeting 4625 genes and the drug library 689 chemical compounds approved by the Food and Drug Administration (FDA). Data were analyzed using protein-protein interaction and pathway analyses. EGFR inhibition was identified as a cardioprotective mechanism in both approaches. Inhibition of EGFR kinase activity with gefitinib improved cardiomyocyte viability in vitro. In addition, gefitinib preserved cardiac contractility in zebrafish embryos exposed to hypoxia-reoxygenation in vivo. These findings indicate that the EGFR inhibitor gefitinib is a potential candidate for further studies of repurposing the drug for the treatment of myocardial infarction.

Pharmacological Protection against Ischemia-Reperfusion Injury by Regulating the Nrf2-Keap1-ARE Signaling Pathway

Ischemia/reperfusion (I/R) injury is associated with substantial clinical implications, including a wide range of organs such as the brain, kidneys, lungs, heart, and many others. I/R injury (IRI) occurs due to the tissue injury following the reestablishment of blood supply to ischemic tissues, leading to enhanced aseptic inflammation and stimulation of oxidative stress via reactive oxygen and nitrogen species (ROS/RNS). Since ROS causes membrane lipids’ peroxidation, triggers loss of membrane integrity, denaturation of proteins, DNA damage, and cell death, oxidative stress plays a critical part in I/R pathogenesis. Therefore, ROS regulation could be a promising therapeutic strategy for IRI. In this context, Nrf2 (NF-E2-related factor 2) is a transcription factor that regulates the expression of several factors involved in the cellular defense against oxidative stress and inflammation, including heme oxygenase-1 (HO-1). Numerous studies have shown the potential role of the Nrf2/HO-1 pathway in IRI; thus, we will review the molecular aspects of Nrf2/Kelch-like ECH-associated protein 1 (Keap1)/antioxidant response element (ARE) signaling pathway in I/R, and we will also highlight the recent insights into targeting this pathway as a promising therapeutic strategy for preventing IRI.

Revealing the synergistic mechanism of Shenfu Decoction for anti-heart failure through network pharmacology strategy

The present study was designed to investigate the targets and synergistic mechanism of Shenfu Decoction (SFD) in the treatment of heart failure. A heart failure animal models was established to evaluate the pharmacological effects of SFD for anti-heart failure, then constructed ingredient-target interaction network by developing ingredient and target databases, the Discovery sdudio software was used for molecular docking. In addition, we validated the predicted protein targets of active ingredients in SFD by using surface plasmon resonance (SPR) technology. Our results demonstrated that SFD could enhance ejection fraction, alleviate myocardial histopathological characteristics, and reduce the level of angiotensin converting enzyme (ACE), aldosterone (ALD), atrial natriuretic polypeptide (ANP) and Renin (REN) in heart failure rat model. In addition, the ingredient database including 349 constituents and target database including 236 proteins were established, and 75 proteins were screened and identified by molecular docking strategy. 22 core target proteins were identified through network pharmacology, and the component-core target network was constructed. Finally, the affinity between the compounds and targets were verified by the SPR analysis method. The present study suggested that SFD may act on ACE 2, REN, ACE, ICAM-1, EGF, HTR2B, PARP1, NPPB and other proteins through AC, BAC, ACN, Re, Rg1, Rb1 to exert synergistic effects against heart failure.

Epidermal growth factor protects against myocardial ischaemia reperfusion injury through activating Nrf2 signalling pathway

Alleviating the oxidant stress associated with myocardial ischaemia reperfusion has been demonstrated as a potential therapeutic approach to limit ischaemia reperfusion (I/R)-induced cardiac damage. It is reported that EGFR/erbB2 signalling is an important cardiac survival pathway in cardiac function and activation of EGFR has a cardiovascular effect in global ischaemia. Epidermal growth factor (EGF), a typical EGFR ligand, was considered to have a significant role in activating EGFR. However, no evidence has been published whether exogenous EGF has protective effects on myocardial ischaemia reperfusion. This study aims to investigate the effects of EGF in I/R-induced heart injury and to demonstrate its mechanisms. H9c2 cells challenged with H₂O₂ were used for in vitro biological activity and mechanistic studies. The malondialdehyde (MDA) and Superoxide Dismutase (SOD) levels in H9c2 cells were determined, and the cell viability was assessed by MTT assay. Myocardial I/R mouse administrated with or without EGF were used for in vivo studies. Pretreatment of H9c2 cells with EGF activated Nrf2 signalling pathway, attenuated H₂O₂-increased MDA and H₂O₂-reduced SOD level, followed by the inhibition of H₂O₂-induced cell death. In in vivo animal models of myocardial I/R, administration of EGF reduced infarct size and myocardial apoptosis. These data support that EGF decreases oxidative stress and attenuates myocardial ischaemia reperfusion injury via activating Nrf2.

Role of Epidermal Growth Factor Receptor (EGFR) and Its Ligands in Kidney Inflammation and Damage

Chronic kidney disease (CKD) is characterized by persistent inflammation and progressive fibrosis, ultimately leading to end-stage renal disease. Although many studies have investigated the factors involved in the progressive deterioration of renal function, current therapeutic strategies only delay disease progression, leaving an unmet need for effective therapeutic interventions that target the cause behind the inflammatory process and could slow down or reverse the development and progression of CKD. Epidermal growth factor receptor (EGFR) (ERBB1), a membrane tyrosine kinase receptor expressed in the kidney, is activated after renal damage, and preclinical studies have evidenced its potential as a therapeutic target in CKD therapy. To date, seven official EGFR ligands have been described, including epidermal growth factor (EGF) (canonical ligand), transforming growth factor-α, heparin-binding epidermal growth factor, amphiregulin, betacellulin, epiregulin, and epigen. Recently, the connective tissue growth factor (CTGF/CCN2) has been described as a novel EGFR ligand. The direct activation of EGFR by its ligands can exert different cellular responses, depending on the specific ligand, tissue, and pathological condition. Among all EGFR ligands, CTGF/CCN2 is of special relevance in CKD. This growth factor, by binding to EGFR and downstream signaling pathway activation, regulates renal inflammation, cell growth, and fibrosis. EGFR can also be “transactivated” by extracellular stimuli, including several key factors involved in renal disease, such as angiotensin II, transforming growth factor beta (TGFB), and other cytokines, including members of the tumor necrosis factor superfamily, showing another important mechanism involved in renal pathology. The aim of this review is to summarize the contribution of EGFR pathway activation in experimental kidney damage, with special attention to the regulation of the inflammatory response and the role of some EGFR ligands in this process. Better insights in EGFR signaling in renal disease could improve our current knowledge of renal pathology contributing to therapeutic strategies for CKD development and progression.

Low-flow ischaemia and reperfusion in rat hearts: energetic of stunning and cardioprotection of genistein

Objectives

Low-flow ischemia (LFI) is consequent to coronary disease and produces cardiac stunning during reperfusion (R). Energetic performance and mechanisms of Ca2+ handling during LFI/R are not known. Moreover, cardioprotection of the phytoestrogen genistein (Gen) remains to be demonstrated in LFI/R. The aim was to study the mechanisms of the stunning consequent to LFI/R and the effects of Gen on both sexes.

Methods

Rat ventricles were perfused inside a calorimeter to measure maximal pressure development (P) and total heat rate (Ht) before and during exposition to LFI/R. The mechanisms of stunning were evaluated with selective drugs.

Key findings

Female hearts (FH) developed higher postischemic contractile recovery (PICR) and muscle economy (P/Ht) than males (MH). Cardioprotection was sensitive to blockade of mKATP channels, UCam and NOS. Perfusion of 20 μmol/l Gen reduced PICR and P/Ht during LFI/R in FH, and dysfunction was increased by mNCX blockade with mPTP opening. However, intraperitoneal 5 mg/kg Gen (Gen-ip) was cardioprotective in both sexes, and the beneficial effect of Gen-ip was blocked by 100 μmol/l 5-HD.

Conclusions

FH are more protected than MH against the LFI/R dysfunction, which involves mitochondrial Ca2+ loss; Gen-ip was more cardioprotective in MH than in FH, mainly by activation of the mKATP channels.

Mitochondrial Transplantation in Myocardial Ischemia and Reperfusion Injury

Ischemic heart disease remains the leading cause of death worldwide. Mitochondria are the power plant of the cardiomyocyte, generating more than 95% of the cardiac ATP. Complex cellular responses to myocardial ischemia converge on mitochondrial malfunction which persists and increases after reperfusion, determining the extent of cellular viability and post-ischemic functional recovery. In a quest to ameliorate various points in pathways from mitochondrial damage to myocardial necrosis, exhaustive pharmacologic and genetic tools have targeted various mediators of ischemia and reperfusion injury and procedural techniques without applicable success. The new concept of replacing damaged mitochondria with healthy mitochondria at the onset of reperfusion by auto-transplantation is emerging not only as potential therapy of myocardial rescue, but as gateway to a deeper understanding of mitochondrial metabolism and function. In this chapter, we explore the mechanisms of mitochondrial dysfunction during ischemia and reperfusion, current developments in the methodology of mitochondrial transplantation, mechanisms of cardioprotection and their clinical implications.

Coupling of myocardial stress resistance and signalling to voluntary activity and inactivity

AIMS

We examined coupling of myocardial ischaemic tolerance to physical activity and inactivity, and whether this involves modulation of survival (AKT, AMPK, ERK1/2, HSP27, EGFR) and injury (GSK3β) proteins implicated in ischaemic preconditioning and calorie restriction.

METHODS

Proteomic modifications were assessed in ventricular myocardium, and tolerance to 25-min ischaemia in ex vivo perfused hearts from C57Bl/6 mice subjected to 14-day voluntary activity in running-naïve animals (Active); 7 days of subsequent inactivity (Inactive); brief (day 3) restoration of running (Re-Active); or time-matched inactivity.

RESULTS

Active mice increased running speed and distance by 75-150% over 14 days (to ~40 m min(-1) and 10 km day(-1) ), with Active hearts resistant to post-ischaemic dysfunction (40-50% improvements in ventricular pressure development, diastolic pressure and dP/dt). Cardioprotection was accompanied by ~twofold elevations in AKT, AMPK, HSP27 and GSK3β phosphorylation and EGFR expression. Ischaemic tolerance was reversed in Inactive hearts, paralleling reduced EGFR expression and GSK3β and ERK1/2 phosphorylation (AKT, AMPK, HSP27 phosphorylation unaltered). Running characteristics, ischaemic tolerance, EGFR expression and GSK3β phosphorylation returned to Active levels within 1-3 days of restored activity (without changes in AKT, AMPK or HSP27 phosphorylation). Transcriptional responses included activity-dependent Anp induction vs. Hmox1 and Sirt3 suppression, and inactivity-dependent Adora2b induction.

CONCLUSIONS

Data confirm the sensitive coupling of ischaemic tolerance to activity: voluntary running induces cardioprotection that dissipates within 1 week of inactivity yet recovers rapidly upon subsequent activity. While exercise in naïve animals induces a molecular profile characteristic of preconditioning/calorie restriction, only GSK3β and EGFR modulation consistently parallel activity- and inactivity-dependent ischaemic tolerance.

Mitochondrial transplantation for therapeutic use

Mitochondria play a key role in the homeostasis of the vast majority of the body's cells. In the myocardium where mitochondria constitute 30 % of the total myocardial cell volume, temporary attenuation or obstruction of blood flow and as a result oxygen delivery to myocardial cells (ischemia) severely alters mitochondrial structure and function. These alterations in mitochondrial structure and function occur during ischemia and continue after blood flow and oxygen delivery to the myocardium is restored, and significantly decrease myocardial contractile function and myocardial cell survival. We hypothesized that the augmentation or replacement of mitochondria damaged by ischemia would provide a mechanism to enhance cellular function and cellular rescue following the restoration of blood flow. To test this hypothesis we have used a model of myocardial ischemia and reperfusion. Our studies demonstrate that the transplantation of autologous mitochondria, isolated from the patient's own body, and then directly injected into the myocardial during early reperfusion augment the function of native mitochondria damaged during ischemia and enhances myocardial post-ischemic functional recovery and cellular viability. The transplanted mitochondria act both extracellularly and intracellularly. Extracellularly, the transplanted mitochondria enhance high energy synthesis and cellular adenosine triphosphate stores and alter the myocardial proteome. Once internalized the transplanted mitochondria rescue cellular function and replace damaged mitochondrial DNA. There is no immune or auto-immune reaction and there is no pro-arrhythmia as a result of the transplanted mitochondria. Our studies and those of others demonstrate that mitochondrial transplantation can be effective in a number of cell types and diseases. These include cardiac and skeletal muscle, pulmonary and hepatic tissue and cells and in neuronal tissue. In this review we discuss the mechanisms leading to mitochondrial dysfunction and the effects on cellular function. We provide a methodology for the isolation of mitochondria to allow for clinical relevance and we discuss the methods we and others have used for the uptake and internalization of mitochondria. We foresee that mitochondrial transplantation will be a valued treatment in the armamentarium of all clinicians and surgeons for the treatment of varied ischemic disorders, mitochondrial diseases and related disorders.

EGF is required for cardiac differentiation of P19CL6 cells through interaction with GATA-4 in a time- and dose-dependent manner

The regulation of cardiac differentiation is critical for maintaining normal cardiac development and function. The precise mechanisms whereby cardiac differentiation is regulated remain uncertain. Here, we have identified a GATA-4 target, EGF, which is essential for cardiogenesis and regulates cardiac differentiation in a dose- and time-dependent manner. Moreover, EGF demonstrates functional interaction with GATA-4 in inducing the cardiac differentiation of P19CL6 cells in a time- and dose-dependent manner. Biochemically, GATA-4 forms a complex with STAT3 to bind to the EGF promoter in response to EGF stimulation and cooperatively activate the EGF promoter. Functionally, the cooperation during EGF activation results in the subsequent activation of cyclin D1 expression, which partly accounts for the lack of additional induction of cardiac differentiation by the GATA-4/STAT3 complex. Thus, we propose a model in which the regulatory cascade of cardiac differentiation involves GATA-4, EGF, and cyclin D1.

Gene Expression Analyses during Spontaneous Reversal of Cardiomyopathy in Mice with Repressed Nuclear CUG-BP, Elav-Like Family (CELF) Activity in Heart Muscle

CUG-BP, Elav-like family (CELF) proteins regulate cell type- and developmental stage-specific alternative splicing in the heart. Repression of CELF-mediated splicing activity via expression of a nuclear dominant negative CELF protein in heart muscle was previously shown to induce dysregulation of alternative splicing, cardiac dysfunction, cardiac hypertrophy, and dilated cardiomyopathy in MHC-CELFΔ transgenic mice. A “mild” line of MHC-CELFΔ mice that expresses a lower level of the dominant negative protein exhibits cardiac dysfunction and myopathy at a young age, but spontaneously recovers normal cardiac function and heart size with age despite the persistence of splicing defects. To the best of our knowledge, this was the first example of a genetically induced cardiomyopathy that spontaneously recovers without intervention. In this study, we explored the basis for this recovery. We examined whether a transcriptional program regulated by serum response factor (SRF) that is dysregulated in juvenile MHC-CELFΔ mice is restored in the mild line with age, and evaluated global changes in gene expression by microarray analyses. We found that differences in gene expression between the mild line and wild type hearts are greatly reduced in older animals, including a partial recovery of SRF target gene expression. We did not find evidence of a new compensatory pathway being activated in the mild line with age, and propose that recovery may occur due to developmental stage-specific compatibility of CELF-dependent splice variants with the cellular environment of the cardiomyocyte.

Epidermal growth factor, from gene organization to bedside

In 1962, epidermal growth factor (EGF) was discovered by Dr. Stanley Cohen while studying nerve growth factor (NGF). It was soon recognized that EGF is the prototypical member of a family of peptide growth factors that activate the EGF receptors, and that the EGF/EGF receptor signaling pathway plays important roles in proliferation, differentiation and migration of a variety of cell types, especially in epithelial cells. After the basic characterization of EGF function in the first decade or so after its discovery, the studies related to EGF and its signaling pathway have extended to a broad range of investigations concerning its biological and pathophysiological roles in development and in human diseases. In this review, we briefly describe the gene organization and tissue distribution of EGF, with emphasis on its biological and pathological roles in human diseases.

Transplantation of autologously derived mitochondria protects the heart from ischemia-reperfusion injury

Mitochondrial damage and dysfunction occur during ischemia and modulate cardiac function and cell survival significantly during reperfusion. We hypothesized that transplantation of autologously derived mitochondria immediately prior to reperfusion would ameliorate these effects. New Zealand White rabbits were used for regional ischemia (RI), which was achieved by temporarily snaring the left anterior descending artery for 30 min. Following 29 min of RI, autologously derived mitochondria (RI-mitochondria; 9.7 ± 1.7 × 10(6)/ml) or vehicle alone (RI-vehicle) were injected directly into the RI zone, and the hearts were allowed to recover for 4 wk. Mitochondrial transplantation decreased (P < 0.05) creatine kinase MB, cardiac troponin-I, and apoptosis significantly in the RI zone. Infarct size following 4 wk of recovery was decreased significantly in RI-mitochondria (7.9 ± 2.9%) compared with RI-vehicle (34.2 ± 3.3%, P < 0.05). Serial echocardiograms showed that RI-mitochondria hearts returned to normal contraction within 10 min after reperfusion was started; however, RI-vehicle hearts showed persistent hypokinesia in the RI zone at 4 wk of recovery. Electrocardiogram and optical mapping studies showed that no arrhythmia was associated with autologously derived mitochondrial transplantation. In vivo and in vitro studies show that the transplanted mitochondria are evident in the interstitial spaces and are internalized by cardiomyocytes 2-8 h after transplantation. The transplanted mitochondria enhanced oxygen consumption, high-energy phosphate synthesis, and the induction of cytokine mediators and proteomic pathways that are important in preserving myocardial energetics, cell viability, and enhanced post-infarct cardiac function. Transplantation of autologously derived mitochondria provides a novel technique to protect the heart from ischemia-reperfusion injury.

Activation of epidermal growth factor receptor mediates reperfusion arrhythmias in anaesthetized rats

AIMS

Epidermal growth factor receptor (EGFR) plays a critical role in the development and function of the heart. Previous studies have demonstrated that EGFR is involved in regulating electrical excitability of the heart. The present study was designed to investigate whether EGFR activation would mediate cardiac arrhythmias induced by reperfusion in anaesthetized rats.

METHODS AND RESULTS

Reperfusion arrhythmias were induced by 10 min ligation of the left anterior descending coronary artery, followed by a 30 min reperfusion in anaesthetized rats. The incidence and severity of cardiac arrhythmias were significantly reduced by pre-treatment with the EGFR kinase inhibitor AG556. The phosphorylation level of myocardial EGFR was increased during ischaemia and at early reperfusion. Intramyocardial transfection of EGFR siRNA reduced EGFR mRNA and protein, and decreased the incidence of ventricular fibrillation induced by reperfusion. Interestingly, tyrosine phosphorylation levels of cardiac Na(+) channels (I(Na)) and L-type Ca(2+) channels (I(Ca,L)) were significantly increased at time points corresponding to the alteration of EGFR phosphorylation levels during reperfusion. AG556 pre-treatment countered the increased tyrosine phosphorylation level of Na(+) and L-type Ca(2+) channels induced by reperfusion. Patch-clamp studies proved that AG556 could inhibit I(Na) and I(Ca,L) in rat ventricular myocytes. No significant alteration was observed in tyrosine phosphorylation levels of cardiac Kv4.2 and Kir2.1 channels during reperfusion.

CONCLUSION

These results demonstrate for the first time that EGFR plays an important role in the genesis of arrhythmias induced by reperfusion, which is likely mediated at least in part by enhancing tyrosine phosphorylation of cardiac Na(+) and L-type Ca(2+) channels.