Novel EGFR inhibitors attenuate cardiac hypertrophy induced by angiotensin II

The role of deubiquitinases in cardiac disease

Deubiquitinases are a group of proteins that identify and digest monoubiquitin chains or polyubiquitin chains attached to substrate proteins, preventing the substrate protein from being degraded by the ubiquitin-proteasome system. Deubiquitinases regulate cellular autophagy, metabolism and oxidative stress by acting on different substrate proteins. Recent studies have revealed that deubiquitinases act as a critical regulator in various cardiac diseases, and control the onset and progression of cardiac disease through a board range of mechanism. This review summarizes the function of different deubiquitinases in cardiac disease, including cardiac hypertrophy, myocardial infarction and diabetes mellitus-related cardiac disease. Besides, this review briefly recapitulates the role of deubiquitinases modulators in cardiac disease, providing the potential therapeutic targets in the future.

DNMT3A clonal hematopoiesis-driver mutations induce cardiac fibrosis by paracrine activation of fibroblasts

Hematopoietic mutations in epigenetic regulators like DNA methyltransferase 3 alpha (DNMT3A), play a pivotal role in driving clonal hematopoiesis of indeterminate potential (CHIP), and are associated with unfavorable outcomes in patients suffering from heart failure (HF). However, the precise interactions between CHIP-mutated cells and other cardiac cell types remain unknown. Here, we identify fibroblasts as potential partners in interactions with CHIP-mutated monocytes. We used combined transcriptomic data derived from peripheral blood mononuclear cells of HF patients, both with and without CHIP, and cardiac tissue. We demonstrate that inactivation of DNMT3A in macrophages intensifies interactions with cardiac fibroblasts and increases cardiac fibrosis. DNMT3A inactivation amplifies the release of heparin-binding epidermal growth factor-like growth factor, thereby facilitating activation of cardiac fibroblasts. These findings identify a potential pathway of DNMT3A CHIP-driver mutations to the initiation and progression of HF and may also provide a compelling basis for the development of innovative anti-fibrotic strategies.

Sesamin suppresses angiotensin-II-enhanced oxidative stress and hypertrophic markers in H9c2 cells

Myocardial hypertrophy plays a crucial role in cardiovascular disease (CVD) development. Myocardial hypertrophy is an adaptive response by myocardial cells to stress after cardiac injury to maintain cardiac output and function. Angiotensin II (Ang-II) regulates CVD through the renin-angiotensin-aldosterone system, and its signaling in cardiac myocytes leads to excessive reactive oxygen species (ROS) production, oxidative stress, and inflammation. Sesamin (SA), a natural compound in sesame seeds, has anti-inflammatory and anti-apoptotic effects. This study investigated whether SA could attenuate hypertrophic damage and oxidative injuries in H9c2 cells under Ang-II stimulation. We found that SA decreased the cell surface area. Furthermore, Ang-II treatment reduced Ang-II-increased ANP, BNP, and β-MHC expression. Ang-II enhanced NADPH oxidase activity, ROS formation, and decreased Superoxide Dismutase (SOD) activity. SA treatment reduces Ang-II-caused oxidative injuries. We also found that SA mitigates Ang-II-induced apoptosis and pro-inflammatory responses. In conclusion, SA could attenuate Ang-II-induced cardiac hypertrophic injuries by inhibiting oxidative stress, apoptosis, and inflammation in H9c2 cells. Therefore, SA might be a potential supplement for CVD management.

Role of c-Src and reactive oxygen species in cardiovascular diseases

Oxidative stress, caused by the over production of oxidants or inactivity of antioxidants, can modulate the redox state of several target proteins such as tyrosine kinases, mitogen-activated protein kinases and tyrosine phosphatases. c-Src is one such non-receptor tyrosine kinase which activates NADPH oxidases (Noxs) in response to various growth factors and shear stress. Interaction between c-Src and Noxs is influenced by cell type and primary messengers such as angiotensin II, which binds to G-protein coupled receptor and activates the intracellular signaling cascade. c-Src stimulated activation of Noxs results in elevated release of intracellular and extracellular reactive oxygen species (ROS). These ROS species disturb vascular homeostasis and cause cardiac hypertrophy, coronary artery disease, atherosclerosis and hypertension. Interaction between c-Src and ROS in the pathobiology of cardiac fibrosis is hypothesized to be influenced by cell type and stimuli. c-Src and ROS have a bidirectional relationship, thus increased ROS levels due to c-Src mediated activation of Noxs can further activate c-Src by promoting the oxidation and sulfenylation of critical cysteine residues. This review highlights the role of c-Src and ROS in mediating downstream signaling pathways underlying cardiovascular diseases. Furthermore, due to the central role of c-Src in activation of various signaling proteins involved in differentiation, migration, proliferation, and cytoskeletal reorganization of vascular cells, it is presented as therapeutic target for treating cardiovascular diseases except cardiac fibrosis.

Material basis and integrative pharmacology of danshen decoction in the treatment of cardiovascular diseases

BACKGROUND

Cardiovascular diseases (CVDs) are among the primary and predominant threats to human health with increasing incidence. Danshen Decoction (DSD) as an adjuvant therapy can benefit CVDs patients by improving clinical efficacy.

PURPOSE

The purpose of this study was to identify the active components and potential pharmacological mechanisms of DSD by combining mass spectrometry with a network pharmacology strategy and to review the use of DSD in the treatment of CVDs.

METHOD

First, the composition of DSD was analyzed by ultrahigh-performance liquid chromatography/tandem mass spectrometry (UHPLC-MS/MS). Second, the network pharmacology method was used to elucidate the underlying material basis and possible pharmacological mechanism of DSD for the treatment of CVDs. Finally, clinical and experimental studies on DSD in the past ten years were retrieved from the PubMed and CNKI database, and the content of these studies was used to summarize the latest progress in DSD treatment of CVDs.

OUTCOME

A total of 35 compounds were found in DSD by manual identification from the analysis of MS, which may be the material basis for the therapeutic effect of DSD. After taking the intersection of 2086 targets related to CVDs, these 35 compounds are considered to play a role in the treatment of CVDs through 210 targets including signal transducer and activator of transcription 3 (STAT3), sarcoma (SRC) and phosphoinositide-3-kinase regulatory subunit (PIK3R), and a total of 168 signaling pathways were involved in the regulation of CVDs by DSD, including PI3K-AKT signaling pathway, Alzheimer disease, and Rap1 signaling pathway. A total of 29 clinical studies using DSD in the treatment of CVDs were included in the literature review, and these studies showed the positive significance of DSD as adjuvant therapy, while 14 experimental studies included in the literature review also demonstrated the effectiveness of DSD in the treatment of CVDs.

CONCLUSION

DSD plays a role in the treatment of CVDs through a variety of active ingredients. Large-scale clinical research and more in-depth experimental research will help to further reveal the mechanism of DSD in the treatment of CVDs.

Signaling network model of cardiomyocyte morphological changes in familial cardiomyopathy

Familial cardiomyopathy is a precursor of heart failure and sudden cardiac death. Over the past several decades, researchers have discovered numerous gene mutations primarily in sarcomeric and cytoskeletal proteins causing two different disease phenotypes: hypertrophic (HCM) and dilated (DCM) cardiomyopathies. However, molecular mechanisms linking genotype to phenotype remain unclear. Here, we employ a systems approach by integrating experimental findings from preclinical studies (e.g., murine data) into a cohesive signaling network to scrutinize genotype to phenotype mechanisms. We developed an HCM/DCM signaling network model utilizing a logic-based differential equations approach and evaluated model performance in predicting experimental data from four contexts (HCM, DCM, pressure overload, and volume overload). The model has an overall prediction accuracy of 83.8%, with higher accuracy in the HCM context (90%) than DCM (75%). Global sensitivity analysis identifies key signaling reactions, with calcium-mediated myofilament force development and calcium-calmodulin kinase signaling ranking the highest. A structural revision analysis indicates potential missing interactions that primarily control calcium regulatory proteins, increasing model prediction accuracy. Combination pharmacotherapy analysis suggests that downregulation of signaling components such as calcium, titin and its associated proteins, growth factor receptors, ERK1/2, and PI3K-AKT could inhibit myocyte growth in HCM. In experiments with patient-specific iPSC-derived cardiomyocytes (MLP-W4R;MYH7-R723C iPSC-CMs), combined inhibition of ERK1/2 and PI3K-AKT rescued the HCM phenotype, as predicted by the model. In DCM, PI3K-AKT-NFAT downregulation combined with upregulation of Ras/ERK1/2 or titin or Gq protein could ameliorate cardiomyocyte morphology. The model results suggest that HCM mutations that increase active force through elevated calcium sensitivity could increase ERK activity and decrease eccentricity through parallel growth factors, Gq-mediated, and titin pathways. Moreover, the model simulated the influence of existing medications on cardiac growth in HCM and DCM contexts. This HCM/DCM signaling model demonstrates utility in investigating genotype to phenotype mechanisms in familial cardiomyopathy.

Alteration in tyrosine phosphorylation of cardiac proteome and EGFR pathway contribute to hypertrophic cardiomyopathy

Alterations of serine/threonine phosphorylation of the cardiac proteome are a hallmark of heart failure. However, the contribution of tyrosine phosphorylation (pTyr) to the pathogenesis of cardiac hypertrophy remains unclear. We use global mapping to discover and quantify site-specific pTyr in two cardiac hypertrophic mouse models, i.e., cardiac overexpression of ErbB2 (TgErbB2) and α myosin heavy chain R403Q (R403Q-αMyHC Tg), compared to control hearts. From this, there are significant phosphoproteomic alterations in TgErbB2 mice in right ventricular cardiomyopathy, hypertrophic cardiomyopathy (HCM), and dilated cardiomyopathy (DCM) pathways. On the other hand, R403Q-αMyHC Tg mice indicated that the EGFR1 pathway is central for cardiac hypertrophy, along with angiopoietin, ErbB, growth hormone, and chemokine signaling pathways activation. Surprisingly, most myofilament proteins have downregulation of pTyr rather than upregulation. Kinase-substrate enrichment analysis (KSEA) shows a marked downregulation of MAPK pathway activity downstream of k-Ras in TgErbB2 mice and activation of EGFR, focal adhesion, PDGFR, and actin cytoskeleton pathways. In vivo ErbB2 inhibition by AG-825 decreases cardiomyocyte disarray. Serine/threonine and tyrosine phosphoproteome confirm the above-described pathways and the effectiveness of AG-825 Treatment. Thus, altered pTyr may play a regulatory role in cardiac hypertrophic models.

Loss of Amphiregulin drives inflammation and endothelial apoptosis in pulmonary hypertension

Pulmonary hypertension (PH) is a vascular disease characterized by elevated pulmonary arterial pressure, leading to right ventricular failure and death. Pathogenic features of PH include endothelial apoptosis and vascular inflammation, which drive vascular remodeling and increased pulmonary arterial pressure. Re-analysis of the whole transcriptome sequencing comparing human pulmonary arterial endothelial cells (PAECs) isolated from PH and control patients identified AREG, which encodes Amphiregulin, as a key endothelial survival factor. PAECs from PH patients and mice exhibited down-regulation of AREG and its receptor epidermal growth factor receptor (EGFR). Moreover, the deficiency of AREG and EGFR in ECs in vivo and in vitro heightened inflammatory leukocyte recruitment, cytokine production, and endothelial apoptosis, as well as diminished angiogenesis. Correspondingly, hypoxic mice lacking Egfr in ECs (cdh5 ^cre/+ Egfr ^fl/fl) displayed elevated RVSP and pulmonary remodeling. Computational analysis identified NCOA6, PHB2, and RRP1B as putative genes regulating AREG in endothelial cells. The master transcription factor of hypoxia HIF-1⍺ binds to the promoter regions of these genes and up-regulates their expression in hypoxia. Silencing of these genes in cultured PAECs decreased inflammation and apoptosis, and increased angiogenesis in hypoxic conditions. Our pathway analysis and gene silencing experiments revealed that BCL2-associated agonist of cell death (BAD) is a downstream mediator of AREG BAD silencing in ECs lacking AREG mitigated inflammation and apoptosis, and suppressed tube formation. In conclusion, loss of Amphiregulin and its receptor EGFR in PH is a crucial step in the pathogenesis of PH, promoting pulmonary endothelial cell death, influx of inflammatory myeloid cells, and vascular remodeling.

Src-homology domain 2 containing protein tyrosine phosphatase-1 (SHP-1) directly binds to proto-oncogene tyrosine-protein kinase Src (c-Src) and promotes the transcriptional activation of connexin 43 (Cx43)

The prevalence of atrial fibrillation (AF), which is one of the common arrhythmias in clinics, is increasing sharply and has affected millions of patients, which is expected to triple by 2050. The purpose of the study was to explore the regulatory relationship between Src-homology domain 2 containing protein tyrosine phosphatase-1 (SHP-1) and proto-oncogene tyrosine-protein kinase Src (c-Src) and the regulation of Connexins 43 (Cx43), and its effect on AF was also studied. Mouse atrial myocyte line (HL-1 cell line) was used as the research object. After overexpression of SHP-1, the expressions of p-c-Src, Cx43, and SHP-1 were detected by Western blot and cellular immunofluorescence, respectively. The location and interaction of SHP-1 and c-Src in the cells were detected by immunofluorescence co-localization and co-immunoprecipitation (Co-IP). The regulation of c-Src and Cx43 was detected by DNA pull down, chromatin co-immunoprecipitation (CHIP), and dual-luciferase reporter system. The results revealed that overexpression of SHP-1 could inhibit the phosphorylation and activation of c-Src and increase the expression of Cx43. Moreover, there was a direct binding between SHP-1 and c-Src, and c-Src could bind to the promoter region of Cx43 and inhibit the transcription of Cx43. In conclusion, SHP-1 could bind to c-Src and inhibit the activity of c-Src, thus enhancing the transcriptional activation of Cx43 and improving the function of gap junction.

The Roles of S100A4 and the EGF/EGFR Signaling Axis in Pulmonary Hypertension with Right Ventricular Hypertrophy

Pulmonary hypertension (PH) is characterized by increased pulmonary arterial pressure caused by the accumulation of mesenchymal-like cells in the pulmonary vasculature. PH can lead to right ventricular hypertrophy (RVH) and, ultimately, heart failure and death. In PH etiology, endothelial-to-mesenchymal transition (EndMT) has emerged as a critical process governing the conversion of endothelial cells into mesenchymal cells, and S100A4, EGF, and EGFR are implicated in EndMT. However, a potential role of S100A4, EGF, and EGFR in PH has to date not been elucidated. We therefore quantified S100A4, EGF, and EGFR in patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (iPAH). To determine specificity for unilateral heart disease, the EndMT biomarker signature was further compared between PH patients presenting with RVH and patients suffering from aortic valve stenosis (AVS) with left ventricular hypertrophy. Reduced S100A4 concentrations were found in CTEPH and iPAH patients with RVH. Systemic EGF was increased in CTEPH but not in iPAH, while AVS patients displayed slightly diminished EGF levels. EGFR was downregulated in all patient groups when compared to healthy controls. Longitudinal data analysis revealed no effect of surgical therapies on EndMT markers. Pulmonary thrombo-endarterectomized samples were devoid of S100A4, while S100A4 tissue expression positively correlated with higher grades of Heath–Edwards histopathological lesions of iPAH-derived lung tissue. Histologically, EGFR was not detectable in CTEPH lungs or in iPAH lesions. Together, our data suggest an intricate role for S100A4 and EGF/EGFR in PH with right heart pathology.

Diversity among differentially expressed genes in atrial appendages of atrial fibrillation: The role and mechanism of SPP1 in atrial fibrosis

BACKGROUND

Structural remodeling plays an important role in the occurrence and maintenance of atrial fibrillation (AF), but the mechanism is currently unclear. This study was designed to investigate the transcriptomic mechanism of structural remodeling of AF through bioinformatic analysis and in vivo and vitro experiments.

METHODS

Transcriptomic datasets were retrieved from the Gene Expression Omnibus (GEO) database, and bioinformatics analysis was performed to screen mRNAs associated with AF. Cell and animal models were constructed to verify the bioinformatic findings using RT-qPCR and western blot analysis. Then, SPP1 was screened as the target gene, and the mechanism by which it promotes fibrosis was further studied in human cardiac fibroblasts (HCFs) using western blot analysis.

RESULTS

After retrieval, the GSE14975, GSE31821, GSE79768, GSE115574 and GSE128188 datasets were used in this study. In total, 147 differentially expressed genes (DEGs) were identified in left atrial appendix tissue and 85 in right atrial appendix tissue. According to the enrichment analysis results, the calcium signaling pathway was found to play an important role in AF, in which EGFR, AGTR1, HTR2B, CD38 and BDKRB1 might be the key genes. Moreover, SPP1 was identified as a key driver through PPI analysis and experimentally proved to reduce the expression of p27 by regulating the PI3K/Akt signaling pathway, sequentially promoting HCF fibrosis.

CONCLUSION

Bioinformatics analysis showed that the calcium signaling pathway might play an important role in AF, while SPP1 could promote myocardial fibrosis through the PI3K/Akt/p27 signaling axis.

An Insight on Multicentric Signaling of Angiotensin II in Cardiovascular system: A Recent Update

The multifaceted nature of the renin-angiotensin system (RAS) makes it versatile due to its involvement in pathogenesis of the cardiovascular disease. Angiotensin II (Ang II), a multifaceted member of RAS family is known to have various potential effects. The knowledge of this peptide has immensely ameliorated after meticulous research for decades. Several studies have evidenced angiotensin I receptor (AT1 R) to mediate the majority Ang II-regulated functions in the system. Functional crosstalk between AT1 R mediated signal transduction cascades and other signaling pathways has been recognized. The review will provide an up-to-date information and recent discoveries involved in Ang II receptor signal transduction and their functional significance in the cardiovascular system for potential translation in therapeutics. Moreover, the review also focuses on the role of stem cell-based therapies in the cardiovascular system.

The Role of Epidermal Growth Factor Receptor Family of Receptor Tyrosine Kinases in Mediating Diabetes-Induced Cardiovascular Complications

Diabetes mellitus is a major debilitating disease whose global incidence is progressively increasing with currently over 463 million adult sufferers and this figure will likely reach over 700 million by the year 2045. It is the complications of diabetes such as cardiovascular, renal, neuronal and ocular dysfunction that lead to increased patient morbidity and mortality. Of these, cardiovascular complications that can result in stroke and cardiomyopathies are 2- to 5-fold more likely in diabetes but the underlying mechanisms involved in their development are not fully understood. Emerging research suggests that members of the Epidermal Growth Factor Receptor (EGFR/ErbB/HER) family of tyrosine kinases can have a dual role in that they are beneficially required for normal development and physiological functioning of the cardiovascular system (CVS) as well as in salvage pathways following acute cardiac ischemia/reperfusion injury but their chronic dysregulation may also be intricately involved in mediating diabetes-induced cardiovascular pathologies. Here we review the evidence for EGFR/ErbB/HER receptors in mediating these dual roles in the CVS and also discuss their potential interplay with the Renin-Angiotensin-Aldosterone System heptapeptide, Angiotensin-(1-7), as well the arachidonic acid metabolite, 20-HETE (20-hydroxy-5, 8, 11, 14-eicosatetraenoic acid). A greater understanding of the multi-faceted roles of EGFR/ErbB/HER family of tyrosine kinases and their interplay with other key modulators of cardiovascular function could facilitate the development of novel therapeutic strategies for treating diabetes-induced cardiovascular complications.

GPCR-ErbB transactivation pathways and clinical implications

Cell surface receptors including the epidermal growth factor receptor (EGFR) family and G-protein coupled receptors (GPCRs) play quintessential roles in physiology, and in diseases, including cardiovascular diseases. While downstream signaling from these individual receptor families has been well studied, the cross-talk between EGF and GPCR receptor families is still incompletely understood. Including members of both receptor families, the number of receptor and ligand combinations for unique interactions is vast, offering a frontier of pharmacologic targets to explore for preventing and treating disease. This molecular cross-talk, called receptor transactivation, is reviewed here with a focus on the cardiovascular system featuring the well-studied GPCR receptors, but also discussing less-studied receptors from both families for a broad understanding of context of expansile interactions, repertoire of cellular signaling, and disease consequences. Attention is given to cell type, level of chronicity, and disease context given that transactivation and comorbidities, including diabetes, hypertension, coronavirus infection, impact cardiovascular disease and health outcomes.

Zinc finger and BTB domain-containing protein 20 aggravates angiotensin II-induced cardiac remodeling via the EGFR-AKT pathway

Zinc finger and BTB domain-containing protein 20 (ZBTB20) play an important role in glucose and lipid homeostasis. ZBTB20 was shown to be a crucial protein for the maintenance of cardiac contractile function. However, the role of ZBTB20 in cardiac response remodeling has not been elucidated. Thus, this study aimed to explore the role of ZBTB20 in cardiac remodeling following angiotensin II insult. Mice were subjected to angiotensin II infusion to induce a cardiac adverse remodeling model. An adeno-associated virus (AAV) 9 system was used to deliver ZBTB20 to the mouse heart. Here, we demonstrate that ZBTB20 expression is elevated in angiotensin II-induced cardiac remodeling and in response to cardiomyocyte insults. Furthermore, AAV9-mediated overexpression of ZBTB20 caused cardiac wall hypertrophy, chamber dilation, increased fibrosis, and reduced ejection fraction. Additionally, ZBTB20 siRNA protected cardiomyocytes from angiotensin II-induced hypertrophy. Mechanistically, ZBTB20 interferes with EGFR and Akt signaling and modulates the remodeling response. Overexpression of constitutively active Akt counteracts ZBTB20 knockdown-mediated protection of adverse cardiac remodeling. These findings illustrate the role of ZBTB20 in the transition of adverse cardiac remodeling toward heart failure and provide evidence for the molecular programs inducing adverse cardiac remodeling. KEY MESSAGES: ZBTB20 is a transcription factor from the POK family. ZBTB20 is upregulated in heart tissue treated with angiotensin II. ZBTB20 influences cardiomyocyte hypertrophy via the EGFR-Akt pathway. Akt continuous activation leads to similar results to ZBTB20 overexpression.

Systematic investigation for the mechanisms and the substance basis of Yang-Xin-Ding-Ji capsule based on the metabolite profile and network pharmacology

Because traditional Chinese medicine (TCM) is a complex mixture of multiple components, the application of methodologies for evaluating single-component Western medicine in TCM studies may have certain limitations. Appropriate strategies that recognize the integrality of TCM and connect to TCM theories remain to be developed. Yang-Xin-Ding-Ji (YXDJ) capsule is originally from a classical TCM formula used for the treatment of arrhythmia. In this study, we used UPLC-Q-TOF-MS detection method, coupled with the metabolic research and network pharmacology analysis, to study the scientific connotation of the YXDJ capsule. A total of 33 absorbed constituents and 23 metabolites were identified or tentatively characterized in dosed plasma and urine, and the possible metabolic pathways were mainly methylation, oxidation, sulfation, glucuronidation, and deglucosylation. We optimized the conventional process ways of network pharmacology by collecting targets based on absorbed constituents into the blood. The constituents-target disease and Kyoto Encyclopedia of Genes pathway analysis revealed that 24 absorbed constituents, 32 target genes, and 10 key pathways were probably related to the efficacy of the YXDJ capsule against arrhythmia. The results provided a scientific basis for understanding the bioactive compounds and the pharmacological mechanism of the YXDJ capsule.

A Bioinformatics Investigation into the Pharmacological Mechanisms of Sodium-Glucose Co-transporter 2 Inhibitors in Diabetes Mellitus and Heart Failure Based on Network Pharmacology

PURPOSE

Diabetes mellitus (DM) is a major risk factor for the development of heart failure (HF). Sodium-glucose co-transporter 2 (SGLT2) inhibitors have demonstrated consistent benefits in the reduction of hospitalization for HF in patients with DM. However, the pharmacological mechanism is not clear. To investigate the mechanisms of SGLT2 inhibitors in DM with HF, we performed target prediction and network analysis by a network pharmacology method.

METHODS

We selected targets of SGLT2 inhibitors and DM status with HF from databases and studies. The "Drug-Target" and "Drug-Target-Disease" networks were constructed using Cytoscape. Then the protein-protein interaction (PPI) was analyzed using the STRING database. Gene Ontology (GO) biological functions and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were performed to investigate using the Bioconductor tool for analysis.

RESULTS

There were 125 effective targets between SGLT2 inhibitors and DM status with HF. Through further screening, 33 core targets were obtained, including SRC, MAPK1, NARS, MAPK3 and EGFR. It was predicted that the Rap1 signaling pathway, MAPK signaling pathway, EGFR tyrosine kinase inhibitor resistance, AGE-RAGE signaling pathway in diabetic complications and other signaling pathways were involved in the treatment of DM with HF by SGLT2 inhibitors.

CONCLUSION

Our study elucidated the possible mechanisms of SGLT2 inhibitors from a systemic and holistic perspective based on pharmacological networks. The key targets and pathways will provide new insights for further research on the pharmacological mechanism of SGLT2 inhibitors in the treatment of DM with HF.

Alkylamino Phenol Derivative Induces Apoptosis by Inhibiting EGFR Signaling Pathway in Breast Cancer Cells

BACKGROUND AND OBJECTIVE

The present study was carried out to evaluate the anticancer property of an alkylamino phenol derivative -2-((3,4-Dihydroquinolin-1(2H)-yl)(p-tolyl)methyl)phenol) (THTMP) against human breast cancer cells. The cytotoxicity of the THTMP was assessed to know its specificity towards breast cancer cells without affecting the normal cells.

METHODS

The THTMP was synthesized and the cytotoxicity was assessed by MTT assay, Caspases enzyme activity, DNA fragmentation and FITC/Annexin V, AO/EtBr staining, RT-PCR and QSAR. In addition, ADME analysis was executed to understand the mode of action of THTMP.

RESULTS

THTMP showed potential cytotoxic activity against the growth of MCF7 and SK-BR3 cells with the IC50 values of 87.92μM and 172.51μM, respectively. Interestingly, THTMP found to activate caspase 3 and caspase 9 enzymes in cancer cells, which are the key enzymes implicated in apoptosis. THTMP induced apoptosis in which 33% of the cells entered the late apoptotic stage after 24h of treatment. The results also revealed that the apoptotic response could be influenced by the association of THTMP with the Epidermal Growth Factor Receptor (EGFR) mediated inhibition of the Phosphatidylinositol 3-Kinase (PI3K)/S6K1 signaling pathway. In addition, docking was performed to study the binding mode of the THTMP, which shows better interaction with EGFR. The structural elucidation of THTMP by Quantitative Structure-Activity Relationship model (QSAR) and ADMET screening suggested, THTMP as an effective anticancer compound.

CONCLUSION

This work strengthens the potential of a promising drug-like compound, THTMP, for the discovery of anticancer drug against breast cancer.

The Impact of microRNAs in Renin-Angiotensin-System-Induced Cardiac Remodelling

Current knowledge on the renin-angiotensin system (RAS) indicates its central role in the pathogenesis of cardiovascular remodelling via both hemodynamic alterations and direct growth and the proliferation effects of angiotensin II or aldosterone resulting in the hypertrophy of cardiomyocytes, the proliferation of fibroblasts, and inflammatory immune cell activation. The noncoding regulatory microRNAs has recently emerged as a completely novel approach to the study of the RAS. A growing number of microRNAs serve as mediators and/or regulators of RAS-induced cardiac remodelling by directly targeting RAS enzymes, receptors, signalling molecules, or inhibitors of signalling pathways. Specifically, microRNAs that directly modulate pro-hypertrophic, pro-fibrotic and pro-inflammatory signalling initiated by angiotensin II receptor type 1 (AT1R) stimulation are of particular relevance in mediating the cardiovascular effects of the RAS. The aim of this review is to summarize the current knowledge in the field that is still in the early stage of preclinical investigation with occasionally conflicting reports. Understanding the big picture of microRNAs not only aids in the improved understanding of cardiac response to injury but also leads to better therapeutic strategies utilizing microRNAs as biomarkers, therapeutic agents and pharmacological targets.

Reversion inducing cysteine rich protein with Kazal motifs and cardiovascular diseases: The RECKlessness of adverse remodeling

The Reversion Inducing Cysteine Rich Protein With Kazal Motifs (RECK) is a glycosylphosphatidylinositol (GPI) anchored membrane-bound regulator of matrix metalloproteinases (MMPs). It is expressed throughout the body and plays a role in extracellular matrix (ECM) homeostasis and inflammation. In initial studies, RECK expression was found to be downregulated in various invasive cancers and associated with poor prognostic outcome. Restoring RECK, however, has been shown to reverse the metastatic phenotype. Downregulation of RECK expression is also reported in non-malignant diseases, such as periodontal disease, renal fibrosis, and myocardial fibrosis. As such, RECK induction has therapeutic potential in several chronic diseases. Mechanistically, RECK negatively regulates various matrixins involved in cell migration, proliferation, and adverse remodeling by targeting the expression and/or activation of multiple MMPs, A Disintegrin And Metalloproteinase Domain-Containing Proteins (ADAMs), and A Disintegrin And Metalloproteinase With Thrombospondin Motifs (ADAMTS). Outside of its role in remodeling, RECK has also been reported to exert anti-inflammatory effects. In cardiac diseases, for example, it has been shown to counteract several downstream effectors of Angiotensin II (Ang-II) that play a role in adverse cardiac and vascular remodeling, such as Interleukin-6 (IL-6)/IL-6 receptor (IL-6R)/glycoprotein 130 (IL-6 signal transducer) signaling and Epidermal Growth Factor Receptor (EGFR) transactivation. This review article focuses on the current understanding of the multifunctional effects of RECK and how its downregulation may contribute to adverse cardiovascular remodeling.

The Role of iRhom2 in Metabolic and Cardiovascular-Related Disorders

Chronic obesity is associated with metabolic imbalance leading to diabetes, dyslipidemia, and cardiovascular diseases (CVDs), in which inflammation is caused by exposure to inflammatory stimuli, such as accumulating sphingolipid ceramides or intracellular stress. This inflammatory response is likely to be prolonged by the effects of dietary and blood cholesterol, thereby leading to chronic low-grade inflammation and endothelial dysfunction. Elevated levels of pro-inflammatory cytokines such as tumor necrosis factor (TNF) are predictive of CVDs and have been widely studied for potential therapeutic strategies. The release of TNF is controlled by a disintegrin and metalloprotease (ADAM) 17 and both are positively associated with CVDs. ADAM17 also cleaves most of the ligands of the epidermal growth factor receptor (EGFR) which have been associated with hypertension, atherogenesis, vascular dysfunction, and cardiac remodeling. The inactive rhomboid protein 2 (iRhom2) regulates the ADAM17-dependent shedding of TNF in immune cells. In addition, iRhom2 also regulates the ADAM17-mediated cleavage of EGFR ligands such as amphiregulin and heparin-binding EGF-like growth factor. Targeting iRhom2 has recently become a possible alternative therapeutic strategy in chronic inflammatory diseases such as lupus nephritis and rheumatoid arthritis. However, what role this intriguing interacting partner of ADAM17 plays in the vasculature and how it functions in the pathologies of obesity and associated CVDs, are exciting questions that are only beginning to be elucidated. In this review, we discuss the role of iRhom2 in cardiovascular-related pathologies such as atherogenesis and obesity by providing an evaluation of known iRhom2-dependent cellular and inflammatory pathways.

Inhibition of the ROS-EGFR Pathway Mediates the Protective Action of Nox1/4 Inhibitor GKT137831 against Hypertensive Cardiac Hypertrophy via Suppressing Cardiac Inflammation and Activation of Akt and ERK1/2

Oxidative stress, inflammation, and hypertension constitute a self-perpetuating vicious circle to exacerbate hypertension and subsequent hypertensive cardiac hypertrophy. NADPH oxidase (Nox) 1/4 inhibitor GKT137831 alleviates hypertensive cardiac hypertrophy in models of secondary hypertension; however, it remains unclear about its effect on hypertensive cardiac hypertrophy in models of essential hypertension. This study is aimed at determining the beneficial role of GKT137831 in hypertensive cardiac hypertrophy in spontaneously hypertensive rats (SHRs) and its mechanisms of action. Treating with GKT137831 prevented cardiac hypertrophy in SHRs. Likewise, decreasing production of reactive oxygen species (ROS) with GKT137831 reduced epidermal growth factor receptor (EGFR) activity in the left ventricle of SHRs. Additionally, EGFR inhibition also reduced ROS production in the left ventricle and blunted hypertensive cardiac hypertrophy in SHRs. Moreover, inhibition of the ROS-EGFR pathway with Nox1/4 inhibitor GKT137831 or selective EGFR inhibitor AG1478 reduced protein and mRNA levels of proinflammatory cytokines tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and interleukin 1β (IL-1β), as well as the activities of Akt and extracellular signal-regulated kinase (ERK) 1/2 in the left ventricle of SHRs. In summary, GKT137831 prevents hypertensive cardiac hypertrophy in SHRs, Nox-deprived ROS regulated EGFR activation through positive feedback in the hypertrophic myocardium, and inhibition of the ROS-EGFR pathway mediates the protective role of GKT137831 in hypertensive cardiac hypertrophy via repressing cardiac inflammation and activation of Akt and ERK1/2. This research will provide additional details for GKT137831 to prevent hypertensive cardiac hypertrophy.

A Novel Rhynchophylline Analog, Y396, Inhibits Endothelial Dysfunction Induced by Oxidative Stress in Diabetes Through Epidermal Growth Factor Receptor

Aims: Endothelial dysfunction appears in early diabetes mellitus partially because of epidermal growth factor receptor (EGFR) abnormal activation and downstream oxidative stress. The aim of this study was to determine whether Y396, a synthesized analog of rhynchophylline, could protect against endothelial dysfunction in diabetes and the underlying molecular mechanism. Results: Y396 could directly target the EGFR and inhibit its phosphorylation induced by high glucose and EGF, downstream translocation to the nucleus of E2F1, and its transcriptional activity and expression of Nox4. Diabetes-induced endothelium malfunction was ameliorated by Y396 treatment through EGFR inhibition. Downstream oxidative stress was decreased by Y396 in the aortas of type 1 diabetes mellitus mice and primary rat aorta endothelial cells (RAECs). Y396 could also ameliorate tunicamycin-induced oxidative stress in the aorta and RAECs. In addition, we again determined the protective effects of Y396 on high-fat diet/streptozotocin-induced type 2 diabetes mellitus. Innovation: This is the first study to demonstrate that Y396, a novel rhynchophylline analog, suppressed high-glucose-induced endothelial malfunction both in vivo and in vitro by inhibiting abnormal phosphorylation of EGFR. Our work uncovered EGFR as a novel therapeutic target and Y396 as a potential therapy against diabetes-induced complication. Conclusion: Y396 could directly bind with EGFR, and inhibit its phosphorylation and downstream E2F1 transcriptional activity. It could also preserve tunicamycin-evoked endothelial dysfunction and oxidative stress. It could protect against diabetes-induced endothelium malfunction in vivo through EGFR inhibition and downstream oxidative stress. Antioxid. Redox Signal. 32, 743-765.

Inhibition of histone demethylase JMJD1C attenuates cardiac hypertrophy and fibrosis induced by angiotensin II

Pathological cardiac hypertrophy is a major risk factor for cardiovascular morbidity and mortality. Histone demethylases (KDMs) are emerging regulators of transcriptional reprograming in cancer, however, their potential role in abnormal heart growth and fibrosis remains largely unknown. The aim of this current study was to examine the role of JMJD1C, an H3K9me2 specific demethylase, in angiotensin II (Ang II) induced cardiac hypertrophy and fibrosis. In this study, we observed that Ang II could increase the expression of JMJD1C detected by Western blot and RT-qPCR in vitro and in vivo. Immunofluorescence staining showed that the treatment of Ang II could increase cardiomyocyte size. RT-qPCR results have shown that Ang II could increase the expression of cell hypertrophic and fibrotic markers in H9c2 cells. Whereas, inhibition of JMJD1C by shRNA and JIB-04, a small molecule histone demethylase inhibitor, significantly reduced Ang II-induced cell hypertrophy, and hypertrophic and fibrotic marker overexpression. Furthermore, cardiomyocyte JMJD1C knockdown decreased Tissue Inhibitor of Metalloproteinases 1 (TIMP1) transcription with pro-fibrotic activity. In conclusion, JMJD1C plays an important role in Ang II-induced cardiac hypertrophy and fibrosis by activating TIMP1 transcription, targeting of JMJD1C may be an effective strategy for the treatment of Ang II-associated cardiac diseases.

Identification of potential microRNAs and their targets in promoting gefitinib resistance by integrative network analysis

Background

Non-small cell lung cancer (NSCLC) accounts for about 80-85% of lung cancers. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as gefitinib are considered the best choice for first-line treatment for the patients with NSCLC harboring EGFR-activating alterations. Nonetheless, 10-30% of patients may not obtain an objective response and may also experience rapid progression. The aim of our research, based on the integrative bioinformatics review, was to identify the possible miRNAs involved in gefitinib resistance.

Method

A gefitinib-resistant network composed of 15 miRNAs and 34 targets were constructed by using the bioinformatics analyses of three microarray datasets. Of these miRNAs, effects of miR-342-3p on gefitinib resistance were investigated on a gefitinib-resistant cell model (A549/GR and PC/GR cells).

Results

We reported that over-expression of miR-342-3p could significantly increase the resistance to gefitinib of A549/GR and PC9/GR cells and vice versa. Then, we recognized CPA4 as a target of hsa-miR-342-3p by a luciferase reporter assay. The increase in hsa-miR-342-3p levels led to a significant reduction in CPA4 protein expression. However, the opposite results were observed upon miR-342-3p knockdown. Finally, we found that enforced CPA4 expression partially reversed miR-342-3p effects in A549/GR cells.

Conclusions

Collectively, these findings suggest that the upregulation of miR-342-3p contributes to gefitinib resistance by targeting CPA4, which may serve as a potential treatment option to overcome gefitinib resistance in patients with NSCLC.

Roselle attenuates cardiac hypertrophy after myocardial infarction in vivo and in vitro

Roselle (Hibiscus sabdariffa Linn) has been traditionally used as folk medicine for hypertension and maintaining cardiovascular health, with therapeutic potential in protecting against numerous cardiovascular diseases. However, it remains unclear whether roselle can be used for management of cardiac hypertrophy seen after myocardial infarction (MI). This study therefore investigated the effects of aqueous roselle extract on cardiac hypertrophy arising from myocardial infarction both in vivo and in vitro. For in vivo study, male Sprague-Dawley rats were divided into control or MI groups (receiving 85 mg/kg isoproterenol s.c. for 2 days) and were given roselle extract (100 mg/kg, p.o daily) for 28 days. Cardiac structure and functional changes were evaluated at study end-point using histology, Langendorff analysis and gene expression analysis. In vitro effects of roselle were also assessed on ANG II-induced cardiomyocytes hypertrophy using H9c2 cells, simulating cardiac hypertrophy evident after MI. Roselle significantly ameliorated MI-induced cardiac systolic and diastolic dysfunction, as seen across improvement in left ventricular developed pressure (LVDP) and its derivative (LVdP/dtmax) and isovolumic relaxation (Tau). Oxidative stress evident across elevated pro-oxidant markers (NOX2 subunit of NADPH oxidase and 8-isoprostane) as well as reduced antioxidant markers (superoxide dismutase and glutathione) were also significantly attenuated by roselle. Furthermore, roselle treatment markedly reduced markers of cardiac remodeling (cardiac hypertrophy and fibrosis) compared to the untreated MI rats. On in vitro analysis, roselle significantly attenuated ANG II-induced cardiomyoycte hypertrophy in dose-dependent manner. This study demonstrated that roselle attenuates cardiac hypertrophy and dysfunction seen after MI both in vivo and in vitro, and these effects are likely mediated by phenolic compounds found in roselle extract.

Osteoglycin attenuates cardiac fibrosis by suppressing cardiac myofibroblast proliferation and migration through antagonizing lysophosphatidic acid 3/matrix metalloproteinase 2/epidermal growth factor receptor signalling

Aims

Cardiac myofibroblasts (CMFs) play a crucial role in the progression of pathological fibrotic cardiac remodelling. The expression of osteoglycin (OGN) is increased in diseased hearts; however, the role of OGN in pathological cardiac remodelling is not understood. Here, we sought to determine the effect of OGN on cardiac interstitial fibrosis and investigate the molecular mechanisms of OGN in CMF activation and matrix production.

Methods and results

We found that OGN expression was significantly upregulated in mouse hearts in response to chronic 14-day angiotensin II (Ang II) infusion. Mice lacking OGN (OGN-/-) exhibited enhanced cardiac interstitial fibrosis and significantly more severe cardiac dysfunction following Ang II infusion compared to wild-type mice. OGN deficiency did not alter blood pressure, nor had effect on transforming growth factor-beta signalling activation, but presented with increased proliferative activity in hearts. In vitro studies with isolated CMFs revealed that OGN deficiency significantly increased proliferation and migration and enhanced the transactivation of epidermal growth factor receptor (EGFR) signalling by Ang II. On the other hand, OGN overexpression in CMFs decreased their proliferation and migration via reducing EGFR activation. Overexpression of OGN also suppressed the shedding of membrane anchored EGFR ligand. Moreover, OGN was found to interact with a lysophosphatidic acid (LPA) receptor isoform 3 and thus to attenuate EGFR transactivation through blocking cell surface translocation of membrane type 1 matrix metalloproteinase (MT1-MMP) and subsequent pro-MMP-2 activation in a Ras homolog gene family, member A (RhoA)/Rho-associated, coiled-coil containing protein kinase (ROCK)-dependent manner.

Conclusion

These findings suggest that OGN negatively regulates cardiac fibrotic remodelling by attenuating CMF proliferation and migration through LPA3-mediated and Rho/ROCK-dependent inhibition of MT1-MMP translocation, MMP2 activation and EGFR transactivation.

Angiotensin II Causes Biphasic STAT3 Activation Through TLR4 to Initiate Cardiac Remodeling

Evidence indicates that Ang II (angiotensin II) activates STAT3 (signal transducer and activator of transcription 3) in cardiomyocytes. However, the mechanisms underlying STAT3 activation and downstream responses are not fully known. In this study, we show that Ang II caused biphasic STAT3 activation in cardiomyocytes. A rapid and early activation was mediated by direct association between TLR4 (toll-like receptor-4) and STAT3. This early activation increased IL-6 (interleukin-6) production, which in turn, induced the second STAT3 activation through the IL-6/gp130 (glycoprotein 130)/JAK2 (Janus-family tyrosine kinases 2) pathway, resulting in unregulated expression of genes for cardiac remodeling. Moreover, STAT3 inhibition or TLR4 knockout in mice protected against Ang II-induced hypertrophy, fibrosis, and cardiac functional deficits. Thus, Ang II-induced STAT3 activation in cardiomyocytes was biphasic, providing a sequential induction of IL-6 and myocardial remodeling genes, respectively. This work supports a novel mechanism on STAT3 activation in Ang II-induced cardiac dysfunction and remodeling.

ERK: A Key Player in the Pathophysiology of Cardiac Hypertrophy

Cardiac hypertrophy is an adaptive and compensatory mechanism preserving cardiac output during detrimental stimuli. Nevertheless, long-term stimuli incite chronic hypertrophy and may lead to heart failure. In this review, we analyze the recent literature regarding the role of ERK (extracellular signal-regulated kinase) activity in cardiac hypertrophy. ERK signaling produces beneficial effects during the early phase of chronic pressure overload in response to G protein-coupled receptors (GPCRs) and integrin stimulation. These functions comprise (i) adaptive concentric hypertrophy and (ii) cell death prevention. On the other hand, ERK participates in maladaptive hypertrophy during hypertension and chemotherapy-mediated cardiac side effects. Specific ERK-associated scaffold proteins are implicated in either cardioprotective or detrimental hypertrophic functions. Interestingly, ERK phosphorylated at threonine 188 and activated ERK5 (the big MAPK 1) are associated with pathological forms of hypertrophy. Finally, we examine the connection between ERK activation and hypertrophy in (i) transgenic mice overexpressing constitutively activated RTKs (receptor tyrosine kinases), (ii) animal models with mutated sarcomeric proteins characteristic of inherited hypertrophic cardiomyopathies (HCMs), and (iii) mice reproducing syndromic genetic RASopathies. Overall, the scientific literature suggests that during cardiac hypertrophy, ERK could be a “good” player to be stimulated or a “bad” actor to be mitigated, depending on the pathophysiological context.

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.

Long Noncoding RNA LINC00460 Promotes the Gefitinib Resistance of Nonsmall Cell Lung Cancer Through Epidermal Growth Factor Receptor by Sponging miR-769-5p

The vital roles of long noncoding RNAs (lncRNAs) in the nonsmall cell lung cancer (NSCLC) tumorigenesis are increasingly important. This work aims to investigate the role of lncRNA LINC00460 in the gefitinib resistance of NSCLC cells and discover its relevant mechanism. Our finding reveals that the expression of lncRNA LINC00460 is upregulated in the gefitinib-resistant NSCLC tissue and cells, and closely correlated with advanced tumor stage and clinical poor prognosis outcome. Gain and loss functional assays are performed in gefitinib-resistant NSCLC cells (A549/GR), stating that LINC00460 facilitates the 50% inhibitive concentration of gefitinib for NSCLC cells, multidrug-resistant-related proteins (P-gp, MRP1, and BCRP), as well as the invasion. In vivo, LINC00460 silencing represses the tumor growth. Bioinformatics prediction tools and luciferase analysis confirm that the upregulated LINC00460 sponged miR-769-5p in NSCLC cells; moreover, epidermal growth factor receptor (EGFR) is identified as a direct target gene of miR-769-5p. Verification experiments confirm that the restoration of EGFR could weaken the sensibility of NSCLC cells toward the gefitinib. In conclusion, our result demonstrates that LINC00460 plays a pivotal role in gefitinib resistance of NSCLC cells by targeting EGFR through sponging miR-769-5p. This finding might serve as a therapeutic target for NSCLC.

Angiotensin II Signal Transduction: An Update on Mechanisms of Physiology and Pathophysiology

The renin-angiotensin-aldosterone system plays crucial roles in cardiovascular physiology and pathophysiology. However, many of the signaling mechanisms have been unclear. The angiotensin II (ANG II) type 1 receptor (AT₁R) is believed to mediate most functions of ANG II in the system. AT₁R utilizes various signal transduction cascades causing hypertension, cardiovascular remodeling, and end organ damage. Moreover, functional cross-talk between AT₁R signaling pathways and other signaling pathways have been recognized. Accumulating evidence reveals the complexity of ANG II signal transduction in pathophysiology of the vasculature, heart, kidney, and brain, as well as several pathophysiological features, including inflammation, metabolic dysfunction, and aging. In this review, we provide a comprehensive update of the ANG II receptor signaling events and their functional significances for potential translation into therapeutic strategies. AT₁R remains central to the system in mediating physiological and pathophysiological functions of ANG II, and participation of specific signaling pathways becomes much clearer. There are still certain limitations and many controversies, and several noteworthy new concepts require further support. However, it is expected that rigorous translational research of the ANG II signaling pathways including those in large animals and humans will contribute to establishing effective new therapies against various diseases.

Novel role for cardiac myocyte-derived β-2 microglobulin in mediating cardiac fibrosis

Hypertension is a significant risk factor for the development of cardiovascular ailments, including ischemic heart disease and diastolic dysfunction. In a recent issue of Clinical Science, Li et al. [Clin. Sci. (2018) 132, 1855-1874] report that β-2 microglobulin (β2M) is a novel secreted soluble factor released by cardiac myocytes during pressure overload that promotes profibrotic gene expression in cardiac fibroblasts both in vitro and in vivo Their study further identifies elevated β2M levels as a possible biomarker for hypertensive patients with cardiac complications. The authors propose a mechanism that mechanically stretched cardiomyocytes release soluble β2M which, through paracrine communication with cardiac fibroblasts, transactivates epidermal growth factor receptor (EGFR) to initiate acute signal transduction and up-regulate profibrotic genes, thereby promoting fibrosis. Here, we will discuss the background, significance of the study, alternative mechanisms, and future directions.

EGFR inhibition attenuates diabetic nephropathy through decreasing ROS and endoplasmic reticulum stress

Diabetic nephropathy (DN) is a progressive kidney disease due to glomerular capillary damage in diabetic patients. Endoplasmic reticulum (ER) stress caused by reactive oxygen species (ROS) is associated with DN progression. Epidermal growth factor receptor (EGFR) mediates oxidative stress and damage of cardiomyocytes in diabetic mice. Here we demonstrated that AG1478, a specific inhibitor of EGFR, blocked EGFR and AKT phosphorylation in diabetic mice. Oxidative stress and ER stress markers were eliminated after AG1478 administration. AG1478 decreased pro-fibrotic genes TGF-β and collagen IV. Furthermore, we found that high glucose (HG) induced oxidative stress and ER stress, and subsequently increased ATF4 and CHOP. These changes were eliminated by either AG1478 or ROS scavenger N-acetyl-L-cysteine (NAC) administration. These results were confirmed by knock-down approaches in renal mesangial SV40 cells. However, AG1478, not NAC, reversed HG induced EGFR and AKT phosphorylation. These results suggest that EGFR/AKT/ROS/ER stress signaling plays an essential role in DN development and inhibiting EGFR may serve as a potential therapeutic strategy in diabetic kidney diseases.

In Silico Analysis of Differential Gene Expression in Three Common Rat Models of Diastolic Dysfunction

Standard therapies for heart failure with preserved ejection fraction (HFpEF) have been unsuccessful, demonstrating that the contribution of the underlying diastolic dysfunction pathophysiology differs from that of systolic dysfunction in heart failure and currently is far from being understood. Complicating the investigation of HFpEF is the contribution of several comorbidities. Here, we selected three established rat models of diastolic dysfunction defined by three major risk factors associated with HFpEF and researched their commonalities and differences. The top differentially expressed genes in the left ventricle of Dahl salt sensitive (Dahl/SS), spontaneous hypertensive heart failure (SHHF), and diabetes 1 induced HFpEF models were derived from published data in Gene Expression Omnibus and used for a comprehensive interpretation of the underlying pathophysiological context of each model. The diversity of the underlying transcriptomic of the heart of each model is clearly observed by the different panel of top regulated genes: the diabetic model has 20 genes in common with the Dahl/SS and 15 with the SHHF models. Advanced analytics performed in Ingenuity Pathway Analysis (IPA^®) revealed that Dahl/SS heart tissue transcripts triggered by upstream regulators lead to dilated cardiomyopathy, hypertrophy of heart, arrhythmia, and failure of heart. In the heart of SHHF, a total of 26 genes were closely linked to cardiovascular disease including cardiotoxicity, pericarditis, ST-elevated myocardial infarction, and dilated cardiomyopathy. IPA Upstream Regulator analyses revealed that protection of cardiomyocytes is hampered by inhibition of the ERBB2 plasma membrane-bound receptor tyrosine kinases. Cardioprotective markers such as natriuretic peptide A (NPPA), heat shock 27 kDa protein 1 (HSPB1), and angiogenin (ANG) were upregulated in the diabetes 1 induced model; however, the model showed a different underlying mechanism with a majority of the regulated genes involved in metabolic disorders. In conclusion, our findings suggest that multiple mechanisms may contribute to diastolic dysfunction and HFpEF, and thus drug therapies may need to be guided more by phenotypic characteristics of the cardiac remodeling events than by the underlying molecular processes.

ErbB2 promotes endothelial phenotype of human left ventricular epicardial highly proliferative cells (eHiPC)

The adult human heart contains a subpopulation of highly proliferative cells. The role of ErbB receptors in these cells has not been studied. From human left ventricular (LV) epicardial biopsies, we isolated highly proliferative cells (eHiPC) to characterize the cell surface expression and function of ErbB receptors in the regulation of cell proliferation and phenotype. We found that human LV eHiPC express all four ErbB receptor subtypes. However, the expression of ErbB receptors varied widely among eHiPC isolated from different subjects. eHiPC with higher cell surface expression of ErbB2 reproduced the phenotype of endothelial cells and were characterized by endothelial cell-like functional properties. We also found that EGF/ErbB1 induces VEGFR2 expression, while ligands for both ErbB1 and ErbB3/4 induce expression of Tie2. The number of CD31posCD45neg endothelial cells is higher in LV biopsies from subjects with high ErbB2 (ErbB2high) eHiPC compared to low ErbB2 (ErbB2low) eHiPC. These findings have important implications for potential strategies to increase the efficacy of cell-based revascularization of the injured heart, through promotion of an endothelial phenotype in cardiac highly proliferative cells.

EGFR activation triggers cellular hypertrophy and lysosomal disease in NAGLU-depleted cardiomyoblasts, mimicking the hallmarks of mucopolysaccharidosis IIIB

Mucopolysaccharidosis (MPS) IIIB is an inherited lysosomal storage disease caused by the deficiency of the enzyme α-N-acetylglucosaminidase (NAGLU) required for heparan sulfate (HS) degradation. The defective lysosomal clearance of undigested HS results in dysfunction of multiple tissues and organs. We recently demonstrated that the murine model of MPS IIIB develops cardiac disease, valvular abnormalities, and ultimately heart failure. To address the molecular mechanisms governing cardiac dysfunctions in MPS IIIB, we generated a model of the disease by silencing NAGLU gene expression in H9C2 rat cardiomyoblasts. NAGLU-depleted H9C2 exhibited accumulation of abnormal lysosomes and a hypertrophic phenotype. Furthermore, we found the specific activation of the epidermal growth factor receptor (EGFR), and increased phosphorylation levels of extracellular signal-regulated kinases (ERKs) in NAGLU-depleted H9C2. The inhibition of either EGFR or ERKs, using the selective inhibitors AG1478 and PD98059, resulted in the reduction of both lysosomal aberration and hypertrophy in NAGLU-depleted H9C2. We also found increased phosphorylation of c-Src and a reduction of the hypertrophic response in NAGLU-depleted H9C2 transfected with a dominant-negative c-Src. However, c-Src phosphorylation remained unaffected by AG1478 treatment, posing c-Src upstream EGFR activation. Finally, heparin-binding EGF-like growth factor (HB-EGF) protein was found overexpressed in our MPS IIIB cellular model, and its silencing reduced the hypertrophic response. These results indicate that both c-Src and HB-EGF contribute to the hypertrophic phenotype of NAGLU-depleted cardiomyoblasts by synergistically activating EGFR and subsequent signaling, thus suggesting that EGFR pathway inhibition could represent an effective therapeutic approach for MPS IIIB cardiac disease.

EGFR mediates hyperlipidemia-induced renal injury via regulating inflammation and oxidative stress: the detrimental role and mechanism of EGFR activation

Previous studies have implicated inflammation, oxidative stress, and fibrosis as key factors in the development of obesity-induced kidney diseases. Epidermal growth factor receptor (EGFR) plays an important role in cancer development. Recently, the EGFR pathway has been increasingly implicated in chronic cardiovascular diseases via regulating inflammation and oxidative stress. However, it is unclear if EGFR is involved in obesity-related kidney injury. Using ApoE-/- and C57BL/6 mice models and two specific EGFR inhibitors, we investigated the potential effects of EGFR inhibition in the treatment of obesity-related nephropathy and found that EGFR inhibition alleviates renal inflammation, oxidative stress and fibrosis. In NRK-52E cells, we also elucidated the mechanism behind hyperlipidemia-induced EGFR activation. We observed that c-Src and EGFR forms a complex, and following PA stimulation, it is the successive phosphorylation, not formation, of the c-Src/EGFR complex that results in the subsequent cascade activation. Second, we found that TLR4 regulates the activation EGFR pathway mainly through the phosphorylation of the c-Src/EGFR complex. These results demonstrate the detrimental role of EGFR in the pathogenesis of obesity-related nephropathy, provide a new understanding of the mechanism behind hyperlipidemia/FFA-induced EGFR activation, and support the use of EGFR inhibitors in the treatment of obesity-induced kidney diseases.

Alterations in NO/ROS ratio and expression of Trx1 and Prdx2 in isoproterenol-induced cardiac hypertrophy

The development of cardiac hypertrophy is a complicated process, which undergoes a transition from compensatory hypertrophy to heart failure, and the identification of new biomarkers and targets for this disease is greatly needed. Here we investigated the development of isoproterenol (ISO)-induced cardiac hypertrophy in an in vitro experimental model. After the induction of hypertrophy with ISO treatment in H9c2 cells, cell surface area, cell viability, cellular reactive oxygen species (ROS), and nitric oxide (NO) levels were tested. Our data showed that the cell viability, mitochondrial membrane potential, and NO/ROS balance varied during the development of cardiac hypertrophy in H9c2 cells. It was also found that the expression of thioredoxin1 (Trx1) and peroxiredoxin2 (Prdx2) was decreased during the cardiac hypertrophy of H9c2 cells. These results suggest a critical role for Trx1 and Prdx2 in the cardiac hypertrophy of H9c2 cells and in the transition from compensated hypertrophy to de-compensated hypertrophy in H9c2 cells, and our findings may have important implications for the management of this disease.

Resveratrol prevents angiotensin II-induced hypertrophy of vascular smooth muscle cells through the transactivation of growth factor receptors

We previously showed that augmented levels of endogenous angiotensin II (AngII) contribute to vascular smooth muscle cell (VSMC) hypertrophy through the transactivation of growth factor receptors in spontaneously hypertensive rats. Resveratrol (RV), a polyphenolic component of red wine, has also been shown to attenuate AngII-evoked VSMC hypertrophy; however, the molecular mechanism mediating this response is obscure. The present study was therefore undertaken to examine whether RV could prevent AngII-induced VSMC hypertrophy through the transactivation of growth factor receptor and associated signaling pathways. AngII treatment of VSMC enhanced the protein synthesis that was attenuated towards control levels by RV pretreatment as well as by the inhibitors of NADPH oxidase, c-Src, and growth factor receptors. Furthermore, RV pretreatment also inhibited enhanced levels of superoxide anion, NADPH oxidase activity, increased expression of NADPH oxidase subunits, and phosphorylation of c-Src, EGF-R, PDGE-R, ERK1/2, and AKT1/2. In conclusion, these results indicate that RV attenuates AngII-induced VSMC hypertrophy through the inhibition of enhanced oxidative stress and activation of c-Src, growth factor receptors, and MAPK/AKT signaling. We suggest that RV could be used as a therapeutic agent in the treatment of vascular complications associated with hypertension and hypertrophy.

Blocking fibrotic signaling in fibroblasts from patients with carpal tunnel syndrome

Fibrosis of the subsynovial connective tissue (SSCT) in carpal tunnel syndrome (CTS) patients is increasingly recognized as an important aspect of CTS pathophysiology. In this study, we evaluated the effect of blocking profibrotic pathways in fibroblasts from the SSCT in CTS patients. Fibroblasts were stimulated with transforming growth factor β1 (TGF-β1), and then treated either with a specific fibrosis pathway inhibitor targeting TGF-β receptor type 1 (TβRI), platelet-derived growth factor receptor (PDGFR), epidermal growth factor receptor (EGFR), or vascular endothelial growth factor receptor (VEGFR). Fibrosis array and quantitative real-time polymerase chain reaction of fibrotic genes were evaluated. Array gene expression analysis revealed significant down-regulation of multiple fibrotic genes after treatment with TβRI, PDGFR, and VEGFR inhibitors. No array fibrotic genes were significantly down-regulated with EGFR inhibition. Further gene expression analysis of known CTS fibrosis markers collagen type I A2 (Col1), collagen type III A1 (Col3), connective tissue growth factor (CTGF), and SERPINE1 showed significantly down-regulation after TβRI inhibition. In contrast, VEGFR inhibition significantly down-regulated CTGF and SERPINE1, whereas, PDGFR and EGFR inhibition significantly down-regulated Col3. Taken together the inhibition of TβRI appears to be the primary mediator of fibrotic gene expression in fibroblasts from CTS patients. TGF-β/Smad activity was further evaluated, and as expected inhibition of Smad activity was significantly down-regulated after inhibition of TβRI, but not with PDGFR, VEGFR, or EGFR inhibition. These results indicate that local therapies specifically targeting TGF-β signaling alone or in combination offer the potential of a novel local antifibrosis therapy for patients with CTS.

Developmental programming: Interaction between prenatal BPA and postnatal overfeeding on cardiac tissue gene expression in female sheep

Epidemiologic studies and studies in rodents point to potential risks from developmental exposure to BPA on cardiometabolic diseases. Furthermore, it is becoming increasingly evident that the manifestation and severity of adverse outcomes is the result of interaction between developmental insults and the prevailing environment. Consistent with this premise, recent studies in sheep found prenatal BPA treatment prevented the adverse effects of postnatal obesity in inducing hypertension. The gene networks underlying these complex interactions are not known. mRNA-seq of myocardium was performed on four groups of four female sheep to assess the effects of prenatal BPA exposure, postnatal overfeeding and their interaction on gene transcription, pathway perturbations and functional effects. The effects of prenatal exposure to BPA, postnatal overfeeding, and prenatal BPA with postnatal overfeeding all resulted in transcriptional changes (85-141 significant differentially expressed genes). Although the effects of prenatal BPA and postnatal overfeeding did not involve dysregulation of many of the same genes, they affected a remarkably similar set of biological pathways. Furthermore, an additive or synergistic effect was not found in the combined treatment group, but rather prenatal BPA treatment led to a partial reversal of the effects of overfeeding alone. Many genes previously known to be affected by BPA and involved in obesity, hypertension, or heart disease were altered following these treatments, and AP-1, EGR1, and EGFR were key hubs affected by BPA and/or overfeeding. Environ. Mol. Mutagen. 58:4-18, 2017. © 2016 Wiley Periodicals, Inc.

Developmental programming: Interaction between prenatal BPA and postnatal overfeeding on cardiac tissue gene expression in female sheep

Epidemiologic studies and studies in rodents point to potential risks from developmental exposure to BPA on cardiometabolic diseases. Furthermore, it is becoming increasingly evident that the manifestation and severity of adverse outcomes is the result of interaction between developmental insults and the prevailing environment. Consistent with this premise, recent studies in sheep found prenatal BPA treatment prevented the adverse effects of postnatal obesity in inducing hypertension. The gene networks underlying these complex interactions are not known. mRNA-seq of myocardium was performed on four groups of four female sheep to assess the effects of prenatal BPA exposure, postnatal overfeeding and their interaction on gene transcription, pathway perturbations and functional effects. The effects of prenatal exposure to BPA, postnatal overfeeding, and prenatal BPA with postnatal overfeeding all resulted in transcriptional changes (85-141 significant differentially expressed genes). Although the effects of prenatal BPA and postnatal overfeeding did not involve dysregulation of many of the same genes, they affected a remarkably similar set of biological pathways. Furthermore, an additive or synergistic effect was not found in the combined treatment group, but rather prenatal BPA treatment led to a partial reversal of the effects of overfeeding alone. Many genes previously known to be affected by BPA and involved in obesity, hypertension, or heart disease were altered following these treatments, and AP-1, EGR1, and EGFR were key hubs affected by BPA and/or overfeeding. Environ. Mol. Mutagen. 58:4-18, 2017. © 2016 Wiley Periodicals, Inc.

Epidermal Growth Factor Receptor Silencing Blunts the Slow Force Response to Myocardial Stretch

Background

Myocardial stretch increases force biphasically: the Frank‐Starling mechanism followed by the slow force response (SFR). Based on pharmacological strategies, we proposed that epidermal growth factor (EGF) receptor (EGFR or ErbB1) activation is crucial for SFR development. Pharmacological inhibitors could block ErbB4, a member of the ErbB family present in the adult heart. We aimed to specifically test the role of EGFR activation after stretch, with an interference RNA incorporated into a lentiviral vector (small hairpin RNA [shRNA]‐EGFR).

Methods and Results

Silencing capability of p‐shEGFR was assessed in EGFR‐GFP transiently transfected HEK293T cells. Four weeks after lentivirus injection into the left ventricular wall of Wistar rats, shRNA‐EGFR–injected hearts showed ≈60% reduction of EGFR protein expression compared with shRNA‐SCR–injected hearts. ErbB2 and ErbB4 expression did not change. The SFR to stretch evaluated in isolated papillary muscles was ≈130% of initial rapid phase in the shRNA‐SCR group, while it was blunted in shRNA‐EGFR–expressing muscles. Angiotensin II (Ang II)‐dependent Na+/H+ exchanger 1 activation was indirectly evaluated by intracellular pH measurements in bicarbonate‐free medium, demonstrating an increase in shRNA‐SCR–injected myocardium, an effect not observed in the silenced group. Ang II‐ or EGF‐triggered reactive oxygen species production was significantly reduced in shRNA‐EGFR–injected hearts compared with that in the shRNA‐SCR group. Chronic lentivirus treatment affected neither the myocardial basal redox state (thiobarbituric acid reactive substances) nor NADPH oxidase activity or expression. Finally, Ang II or EGF triggered a redox‐sensitive pathway, leading to p90RSK activation in shRNA‐SCR‐injected myocardium, an effect that was absent in the shRNA‐EGFR group.

Conclusions

Our results provide evidence that specific EGFR activation after myocardial stretch is a key factor in promoting the redox‐sensitive kinase activation pathway, leading to SFR development.

EGFR Inhibition Blocks Palmitic Acid-induced inflammation in cardiomyocytes and Prevents Hyperlipidemia-induced Cardiac Injury in Mice

Obesity is often associated with increased risk of cardiovascular diseases. Previous studies suggest that epidermal growth factor receptor (EGFR) antagonism may be effective for the treatment of angiotensin II-induced cardiac hypertrophy and diabetic cardiomyopathy. This study was performed to demonstrate if EGFR plays a role in the pathogenesis of hyperlipidemia/obesity-related cardiac injuries. The in vivo studies using both wild type (WT) and apolipoprotein E (ApoE) knockout mice fed with high fat diet (HFD) showed the beneficial effects of small-molecule EGFR inhibitors, AG1478 and 542, against obesity-induced myocardial injury. Administration of AG1478 and 542 significantly reduced myocardial inflammation, fibrosis, apoptosis, and dysfunction in both two obese mouse models. In vitro, EGFR signaling was blocked by either siRNA silencing or small-molecule EGFR inhibitors in palmitic acid (PA)-stimulated cardiomyocytes. EGFR inhibition attenuated PA-induced inflammatory response and apoptosis in H9C2 cells. Furthermore, we found that PA-induced EGFR activation was mediated by the upstream TLR4 and c-Src. This study has confirmed the detrimental effect of EGFR activation in the pathogenesis of obesity-induced cardiac inflammatory injuries in experimental mice, and has demonstrated the TLR4/c-Src-mediated mechanisms for PA-induced EGFR activation. Our data suggest that EGFR may be a therapeutic target for obesity-related cardiovascular diseases.