Activation of Notch-mediated protective signaling in the myocardium

The genetics of spontaneous coronary artery dissection: a scoping review

BACKGROUND

Spontaneous coronary artery dissection (SCAD) is a multifactorial process that involves predisposing factors and precipitating stressors. Genetic abnormality has been implicated to play a mechanistic role in the development of SCAD. This systematic review aims to summarize the current evidence concerning the link between SCAD and genetic abnormalities.

METHODS

We reviewed original studies published until May 2023 that reported SCAD patients with a genetic mutation by searching PubMed, Embase Ovid, and Google Scholar. Registries, cohort studies, and case reports were included if a definitive SCAD diagnosis was reported, and the genetic analysis was performed. Exclusion criteria included editorials, reviews, letters or commentaries, animal studies, meeting papers, and studies from which we were unable to extract data. Data were extracted from published reports.

RESULTS

A total of 595 studies were screened and 55 studies were identified. Among 116 SCAD patients with genetic abnormalities, 20% had mutations in the COL gene, 13.70% TLN1 gene, and 8.42% TSR1 gene. Mutations affecting the genes encoding COL and TLN1 were most frequently reported (20 and 13.7%, respectively). Interestingly, 15 genes of this collection were also reported in patients with thoracic aortic diseases as well. The genetic commonality between fibromuscular dysplasia (FMD) and SCAD was also included.

CONCLUSION

In this review, the inherited conditions and reported genes of undetermined significance from case reports associated with SCAD are collected. A brief description of the encoded protein and the clinical features associated with pathologic genes is provided. Current data suggested that the diagnostic yield of genetic studies for patients with SCAD would be low and routine genetic screening of such patients with no clinical features indicative of associated disorders remains debatable. This review can be used as a guide for clinicians to recognize inherited syndromic and nonsyndromic disorders associated with SCAD.

Dibenzazepine, a γ-Secretase Enzyme Inhibitor, Protects Against Doxorubicin-Induced Cardiotoxicity by Suppressing NF-κB, iNOS, and Hes1/Hey1 Expression

Doxorubicin (DOX) is an effective chemotherapeutic drug; however, its cardiotoxicity and resistance compromise its therapeutic index. The Notch pathway was reported to contribute to DOX cancer resistance. The role of Notch pathway in DOX cardiotoxicity has not been identified yet. Notch receptors are characterized by their extracellular (NECD) and intracellular (NICD) domains (NICD). The γ-secretase enzyme helps in the release of NICD. Dibenzazepine (DBZ) is a γ-secretase inhibitor. The present study investigated the effect of Notch pathway inhibition on DOX cardiotoxicity. Twenty-four male Wistar rats were divided into four groups: control group, DOX group, acute cardiotoxicity was induced by a single dose of DOX (20 mg/kg) i.p., DOX (20 mg/kg) plus DBZ group, and DBZ group. The third and fourth groups received i.p. injection of DBZ daily for 14 days at 2 mg/kg dose. DOX cardiotoxicity increased the level of serum creatine kinase-MB and cardiac troponin I, and it was confirmed by the histopathological examination. Moreover, the antioxidants glutathione peroxidase and superoxide dismutase levels were markedly decreased, and the inflammatory markers, inducible nitric oxide synthase, nuclear factor-ķB, and tumor necrosis factor-α were markedly increased. Furthermore, DOX increased BAX protein and downregulated BCL-2. In addition, DOX upregulated Notch pathway-related parameters: Hes1 and Hey1 mRNA levels, and increased Hes1 protein levels. DBZ ameliorated DOX-induced cardiotoxicity, evidenced by reducing the cardiac injury biomarkers, improving cardiac histopathological changes, correcting antioxidant levels, and reducing inflammatory and apoptotic proteins. Our study indicates the protective effect of Notch inhibitor against DOX-induced cardiotoxicity.

Identification and Validation of Diagnostic Model Based on Angiogenesis- and Epithelial Mesenchymal Transition-Related Genes in Myocardial Infarction

Background

Myocardial infarction (MI) is a chronic cardiovascular disease. This study aims to discern potentially angiogenesis- and epithelial mesenchymal transition (EMT)-related genes as biomarkers for MI diagnosis through bioinformatics.

Methods

All datasets and angiogenesis- and EMT-related genes were collected from the public database. The differentially expressed genes (DEGs) of MI and MI-related genes were acquired. DEGs, MI-related genes, and angiogenesis- and EMT-related genes were intersected to obtain hub genes. Functional enrichment, immune microenvironment, and transcription factors (TFs)-hub genes regulatory network analysis were performed. The diagnostic markers and models were developed and validated. Drug prediction and molecular docking were performed. Finally, diagnostic markers expressions were validated using RT-qPCR.

Results

A total of 224 angiogenesis- and EMT-related genes, 2,897 DEGs, 1,217 MI-related genes, and 9 hub genes were acquired. The immune infiltration levels of plasma cells, T cells CD4 memory activated, monocytes, macrophages M0, mast cells resting, and neutrophils were higher in patients with MI. LRPAP1, COLGALT1, QSOX1, THBD, VCAN, PLOD1, and PLAUR as the diagnostic markers were identified and used to construct diagnostic models, which can distinguish MI from controls well. Then, 9 drugs were screened, and the binding energies ranged from -7.08 to -5.21 kcal/mol. RT-qPCR results showed that the expression of LRPAP1, PLAUR, and PLOD1 was significantly increased in the MI group.

Conclusion

The 7 diagnostic markers may play potential roles in MI and could contribute to improved future diagnostics.

Habitual Daily Intake of Fried Foods Raises Transgenerational Inheritance Risk of Heart Failure Through NOTCH1-Triggered Apoptosis

Consumption of fried foods is highly prevalent in the Western dietary pattern. Western diet has been unfavorably linked with high risk of developing cardiovascular diseases. Heart failure (HF) as a cardiovascular disease subtype is a growing global pandemic with high morbidity and mortality. However, the causal relationship between long-term fried food consumption and incident HF remains unclear. Our population-based study revealed that frequent fried food consumption is strongly associated with 15% higher risk of HF. The causal relationship may be ascribed to the dietary acrylamide exposure in fried foods. Further cross-sectional study evidenced that acrylamide exposure is associated with an increased risk of HF. Furthermore, we discover and demonstrate that chronic acrylamide exposure may induce HF in zebrafish and mice. Mechanistically, we reveal that acrylamide induces energy metabolism disturbance in heart due to the mitochondria dysfunction and metabolic remodeling. Moreover, acrylamide exposure induces myocardial apoptosis via inhibiting NOTCH1-phosphatidylinositol 3-kinase/AKT signaling. In addition, acrylamide exposure could affect heart development during early life stage, and the adverse effect of acrylamide exposure is a threat for next generation via epigenetic change evoked by DNA methyltransferase 1 (DNMT1). In this study, we reveal the adverse effects and underlying mechanism of fried foods and acrylamide as a typical food processing contaminant on HF from population-based observations to experimental validation. Collectively, these results both epidemiologically and mechanistically provide strong evidence to unravel the mechanism of acrylamide-triggered HF and highlight the significance of reducing fried food consumption for lower the risk of HF.

ErbB2-NOTCH1 axis controls autophagy in cardiac cells

Although the epidermal growth factor receptor 2 (ErbB2) and Notch1 signaling pathways have both significant roles in regulating cardiac biology, their interplay in the heart remains poorly investigated. Here, we present evidence of a crosstalk between ErbB2 and Notch1 in cardiac cells, with effects on autophagy and proliferation. Overexpression of ErbB2 in H9c2 cardiomyoblasts induced Notch1 activation in a post-transcriptional, p38-dependent manner, while ErbB2 inhibition with the specific inhibitor, lapatinib, reduced Notch1 activation. Moreover, incubation of H9c2 cells with lapatinib resulted in stalled autophagic flux and decreased proliferation, consistent with the established cardiotoxicity of this and other ErbB2-targeting drugs. Confirming the findings in H9c2 cells, exposure of primary neonatal mouse cardiomyocytes to exogenous neuregulin-1, which engages ErbB2, stimulated proliferation, and this effect was abrogated by concomitant inhibition of the enzyme responsible for Notch1 activation. Furthermore, the hearts of transgenic mice specifically overexpressing ErbB2 in cardiomyocytes had increased levels of active Notch1 and of Notch-related genes. These data expand the knowledge of ErbB2 and Notch1 functions in the heart and may allow better understanding the mechanisms of the cardiotoxicity of ErbB2-targeting cancer treatments.

Low expression of Notch1 may be associated with acute myocardial infarction

Background

The transmembrane protein Notch1 is associated with cell growth, development, differentiation, proliferation, apoptosis, adhesion, and the epithelial mesenchymal transition. Proteomics, as a research method, uses a series of sequencing techniques to study the composition, expression levels, and modifications of proteins. Here, the association between Notch1 and acute myocardial infarction (AMI) was investigated using proteomics, to assess the possibility of using Notch1 as a biomarker for the disease.

Methods

Fifty-five eligible patients with AMI and 74 with chronic coronary syndrome (CCS) were enrolled, representing the experimental and control groups, respectively. The mRNA levels were assessed using RT-qPCR and proteins were measured using ELISA, and the results were compared and analyzed.

Results

Notch1 mRNA levels were 0.52 times higher in the peripheral blood mononuclear cells of the AMI group relative to the CCS group (p < 0.05) while Notch1 protein levels were 0.63 times higher in peripheral blood plasma in AMI patients (p < 0.05). Notch1 levels were not associated with older age, hypertension, smoking, high abdominal-blood glucose, high total cholesterol, and high LDL in AMI. Logistic regression indicated associations between AMI and reduced Notch1 expression, hypertension, smoking, and high fasting glucose.

Conclusions

Notch1 expression was reduced in the peripheral blood of patients with AMI relative to those with CCS. The low expression of Notch1 was found to be an independent risk factor for AMI and may thus be an indicator of the disease.

Cardiac regeneration: Pre-existing cardiomyocyte as the hub of novel signaling pathway

In the mammalian heart, cardiomyocytes are forced to withdraw from the cell cycle shortly after birth, limiting the ability of the heart to regenerate and repair. The development of multimodal regulation of cardiac proliferation has verified that pre-existing cardiomyocyte proliferation is an essential driver of cardiac renewal. With the continuous development of genetic lineage tracking technology, it has been revealed that cell cycle activity produces polyploid cardiomyocytes during the embryonic, juvenile, and adult stages of cardiogenesis, but newly formed mononucleated diploid cardiomyocytes also elevated sporadically during myocardial infarction. It implied that adult cardiomyocytes have a weak regenerative capacity under the condition of ischemia injury, which offers hope for the clinical treatment of myocardial infarction. However, the regeneration frequency and source of cardiomyocytes are still low, and the mechanism of regulating cardiomyocyte proliferation remains further explained. It is noteworthy to explore what force triggers endogenous cardiomyocyte proliferation and heart regeneration. Here, we focused on summarizing the recent research progress of emerging endogenous key modulators and crosstalk with other signaling pathways and furnished valuable insights into the internal mechanism of heart regeneration. In addition, myocardial transcription factors, non-coding RNAs, cyclins, and cell cycle-dependent kinases are involved in the multimodal regulation of pre-existing cardiomyocyte proliferation. Ultimately, awakening the myocardial proliferation endogenous modulator and regeneration pathways may be the final battlefield for the regenerative therapy of cardiovascular diseases.

Epigenetic Contributions to Clinical Risk Prediction of Cardiovascular Disease

BACKGROUND

Cardiovascular disease (CVD) is among the leading causes of death worldwide. The discovery of new omics biomarkers could help to improve risk stratification algorithms and expand our understanding of molecular pathways contributing to the disease. Here, ASSIGN-a cardiovascular risk prediction tool recommended for use in Scotland-was examined in tandem with epigenetic and proteomic features in risk prediction models in ≥12 657 participants from the Generation Scotland cohort.

METHODS

Previously generated DNA methylation-derived epigenetic scores (EpiScores) for 109 protein levels were considered, in addition to both measured levels and an EpiScore for cTnI (cardiac troponin I). The associations between individual protein EpiScores and the CVD risk were examined using Cox regression (ncases≥1274; ncontrols≥11 383) and visualized in a tailored R application. Splitting the cohort into independent training (n=6880) and test (n=3659) subsets, a composite CVD EpiScore was then developed.

RESULTS

Sixty-five protein EpiScores were associated with incident CVD independently of ASSIGN and the measured concentration of cTnI (P<0.05), over a follow-up of up to 16 years of electronic health record linkage. The most significant EpiScores were for proteins involved in metabolic, immune response, and tissue development/regeneration pathways. A composite CVD EpiScore (based on 45 protein EpiScores) was a significant predictor of CVD risk independent of ASSIGN and the concentration of cTnI (hazard ratio, 1.32; P=3.7×10-3; 0.3% increase in C-statistic).

CONCLUSIONS

EpiScores for circulating protein levels are associated with CVD risk independent of traditional risk factors and may increase our understanding of the etiology of the disease.

Ischemia-reperfusion injury: molecular mechanisms and therapeutic targets

Ischemia-reperfusion (I/R) injury paradoxically occurs during reperfusion following ischemia, exacerbating the initial tissue damage. The limited understanding of the intricate mechanisms underlying I/R injury hinders the development of effective therapeutic interventions. The Wnt signaling pathway exhibits extensive crosstalk with various other pathways, forming a network system of signaling pathways involved in I/R injury. This review article elucidates the underlying mechanisms involved in Wnt signaling, as well as the complex interplay between Wnt and other pathways, including Notch, phosphatidylinositol 3-kinase/protein kinase B, transforming growth factor-β, nuclear factor kappa, bone morphogenetic protein, N-methyl-D-aspartic acid receptor-Ca2+-Activin A, Hippo-Yes-associated protein, toll-like receptor 4/toll-interleukine-1 receptor domain-containing adapter-inducing interferon-β, and hepatocyte growth factor/mesenchymal-epithelial transition factor. In particular, we delve into their respective contributions to key pathological processes, including apoptosis, the inflammatory response, oxidative stress, extracellular matrix remodeling, angiogenesis, cell hypertrophy, fibrosis, ferroptosis, neurogenesis, and blood-brain barrier damage during I/R injury. Our comprehensive analysis of the mechanisms involved in Wnt signaling during I/R reveals that activation of the canonical Wnt pathway promotes organ recovery, while activation of the non-canonical Wnt pathways exacerbates injury. Moreover, we explore novel therapeutic approaches based on these mechanistic findings, incorporating evidence from animal experiments, current standards, and clinical trials. The objective of this review is to provide deeper insights into the roles of Wnt and its crosstalk signaling pathways in I/R-mediated processes and organ dysfunction, to facilitate the development of innovative therapeutic agents for I/R injury.

Nrf2 for a key member of redox regulation: A novel insight against myocardial ischemia and reperfusion injuries

Nuclear factor erythroid-2 related factor 2 (Nrf2), a nuclear transcription factor, modulates genes responsible for antioxidant responses against toxic and oxidative stress to maintain redox homeostasis and participates in varieties of cellular processes such as metabolism and inflammation during myocardial ischemia and reperfusion injuries (MIRI). The accumulation of reactive oxygen species (ROS) from damaged mitochondria, xanthine oxidase, NADPH oxidases, and inflammation contributes to depraved myocardial ischemia and reperfusion injuries. Considering that Nrf2 played crucial roles in antagonizing oxidative stress, it is reasonable to delve into the up or down-regulated molecular mechanisms of Nrf2 in the progression of MIRI to provide the possibility of new therapeutic medicine targeting Nrf2 in cardiovascular diseases. This review systematically describes the generation of ROS, the regulatory metabolisms of Nrf2 as well as several natural or synthetic compounds activating Nrf2 during MIRI, which might provide novel insights for the anti-oxidative stress and original ideas targeting Nrf2 for the prevention and treatment in cardiovascular diseases.

Networks that Govern Cardiomyocyte Proliferation to Facilitate Repair of the Injured Mammalian Heart

Cardiovascular diseases are the number one cause of death worldwide and in the United States (US). Cardiovascular diseases frequently progress to end-stage heart failure, and curative therapies are extremely limited. Intense interest has focused on deciphering the cascades and networks that govern cardiomyocyte proliferation and regeneration of the injured heart. For example, studies have shown that lower organisms such as the adult newt and adult zebrafish have the capacity to completely regenerate their injured heart with restoration of function. Similarly, the neonatal mouse and pig are also able to completely regenerate injured myocardium due to cardiomyocyte proliferation from preexisting cardiomyocytes. Using these animal models and transcriptome analyses, efforts have focused on the definition of factors and signaling pathways that can reactivate and induce cardiomyocyte proliferation in the adult mammalian injured heart. These studies and discoveries have the potential to define novel therapies to promote cardiomyocyte proliferation and repair of the injured, mammalian heart.

Effect of humanine on the Notch signaling pathway in myocardial infarction

Background/aim

By applying humanin (HN) before myocardial infarction (MI), its protection in myocardial injury and the possible roles of its cellular mechanism in the Notch pathway were investigated.

Materials and methods

The study was carried out at Fırat University Experimental Research Center (12/24/2018-12/23/2019). Spraque-Dawley rats were divided into 10 groups: I (control) (n = 6), II (HN 6 h) (n = 6), III (HN 24 h) (n = 6), IV (HN day 7) (n = 6), V (MI 6 h) (n = 7), VI (MI 24 h) (n = 7), VII (MI day 7) (n = 7), VIII (MI+HN 6 h) (n = 7), IX (MI+HN 24 h) (n = 7), and X (MI+HN day 7) (n = 7). To create MI, 200 mg/kg of isoproterenol (ISO) was administered to the rats subcutaneously. Moreover, 252 μg/kg of HN was given intraperitoneally (ip) to the rats on its own and before MI. Molecular parameters Notch1, Notch2, Hes1, Hes2, Jagged1, Jagged2, DLL1, and DLL4 were examined using polymerase chain reaction in the heart tissue, Notch1, Hes1, and DLL4 were examined using western blot, while heart tissue was taken for histochemical examinations.

Results

The mRNA expression levels of the Notch signaling members (Notch1, Notch2, Hes1, Hes2, Jagged1, Jagged2, DLL1, and DLL4) tended to decrease after MI. The Notch signaling members increased more significantly, especially toward day 7 after HN application before MI. In the western blot anylyses, the Notch1, Hes1, and DLL4 protein levels increased significantly toward day 7 in the groups given HN before MI. Moreover, the serum AST, LDH, CK-MB, and troponin I levels tended to decrease with the application of HN before MI and there was a significant decrease in edema, hemorrhage, and mononuclear cells in the heart tissue at 24 h post-MI and fibrosis on day 7 post-MI.

Conclusion

HN administration before MI has a cardioprotective effect on rats via the Notch signaling pathway.

The role of PI3K/AKT signaling pathway in myocardial ischemia-reperfusion injury

Myocardial ischemia has a high incidence and mortality rate, and reperfusion is currently the standard intervention. However, reperfusion may lead to further myocardial damage, known as myocardial ischemia/reperfusion injury (MIRI). There are currently no effective clinical treatments for MIRI. The PI3K/Akt signaling pathway is involved in cardiovascular health and disease and plays an important role in reducing myocardial infarct size and restoring cardiac function after MIRI. Activation of the PI3K/Akt pathway provides myocardial protection through synergistic upregulation of antioxidant, anti-inflammatory, and autophagy activities and inhibition of mitochondrial dysfunction and cardiomyocyte apoptosis. Many studies have shown that PI3K/Akt has a significant protective effect against MIRI. Here, we reviewed the molecular regulation of PI3K/Akt in MIRI and summarized the molecular mechanism by which PI3K/Akt affects MIRI, the effects of ischemic preconditioning and ischemic postconditioning, and the role of related drugs or activators targeting PI3K/Akt in MIRI, providing novel insights for the formulation of myocardial protection strategies. This review provides evidence of the role of PI3K/Akt activation in MIRI and supports its use as a therapeutic target.

New Insights into the Reparative Angiogenesis after Myocardial Infarction

Myocardial infarction (MI) causes massive loss of cardiac myocytes and injury to the coronary microcirculation, overwhelming the limited capacity of cardiac regeneration. Cardiac repair after MI is finely organized by complex series of procedures involving a robust angiogenic response that begins in the peri-infarcted border area of the infarcted heart, concluding with fibroblast proliferation and scar formation. Efficient neovascularization after MI limits hypertrophied myocytes and scar extent by the reduction in collagen deposition and sustains the improvement in cardiac function. Compelling evidence from animal models and classical in vitro angiogenic approaches demonstrate that a plethora of well-orchestrated signaling pathways involving Notch, Wnt, PI3K, and the modulation of intracellular Ca2+ concentration through ion channels, regulate angiogenesis from existing endothelial cells (ECs) and endothelial progenitor cells (EPCs) in the infarcted heart. Moreover, cardiac repair after MI involves cell-to-cell communication by paracrine/autocrine signals, mainly through the delivery of extracellular vesicles hosting pro-angiogenic proteins and non-coding RNAs, as microRNAs (miRNAs). This review highlights some general insights into signaling pathways activated under MI, focusing on the role of Ca2+ influx, Notch activated pathway, and miRNAs in EC activation and angiogenesis after MI.

Proteomic analysis of transcription factors involved in the alteration of ischemic mouse heart as modulated by MSC exosomes

Mesenchymal stem cell (MSC) exosomes have been found to attenuate cardiac systolic and diastolic dysfunction in animal models of ischemia. Exosomes carry a plethora of active and inactive proteins as their cargo, which are readily available to the recipient cell for use in intracellular signaling pathways-depending on the stresses, such as ischemia or hypoxia. Among the exosomal proteins are the often-overlooked cargo of transcriptional regulators. These transcriptional regulators influence the transcriptome and subsequently the proteome of recipient cell. Here, we report the transcriptional factors and regulators differentially modulated and their potential role in modulating cardiac function in MSC exosome treated ischemic mice hearts. Our analysis shows ischemic stress modulating transcriptional regulators and factors such as HSF1 and HIF1A in the infarct and peri-infarct areas of ischemic hearts which is mitigated by MSC exosomes. Similarly, STAT3 and SMAD3 are also modulated by MSC exosomes. Interestingly, NOTCH1 and β-catenin were detected in the ischemic hearts. The differential expression of these regulators and factors drives changes in various biological process governed in the ischemic cardiac cells. We believe these studies will advance our understanding of cardiac dysfunction occurring in the ischemic hearts and lay the groundwork for further studies on the modulation of cardiac function during ischemia by MSC exosomes.

A perspective on Notch signalling in progression and arrhythmogenesis in familial hypertrophic and dilated cardiomyopathies

In this perspective, we discussed emerging data indicating a role for Notch signalling in inherited disorders of the heart failure with focus on hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) linked to variants of genes encoding mutant proteins of the sarcomere. We recently reported an upregulation of elements in the Notch signalling cascade in cardiomyocytes derived from human inducible pluripotent stem cells expressing a TNNT2 variant encoding cardiac troponin T (cTnT-I79N+/-), which induces hypertrophy, remodelling, abnormalities in excitation-contraction coupling and electrical instabilities (Shafaattalab S et al. 2021 Front. Cell Dev. Biol. 9, 787581. (doi:10.3389/fcell.2021.787581)). Our search of the literature revealed the novelty of this finding and stimulated us to discuss potential connections between the Notch signalling pathway and familial cardiomyopathies. Our considerations focused on the potential role of these interactions in arrhythmias, microvascular ischaemia, and fibrosis. This finding underscored a need to consider the role of Notch signalling in familial cardiomyopathies which are trigged by sarcomere mutations engaging mechano-signalling pathways for which there is evidence of a role for Notch signalling with crosstalk with Hippo signalling. Our discussion included a role for both cardiac myocytes and non-cardiac myocytes in progression of HCM and DCM. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.

NONHSAT098487.2 protects cardiomyocytes from oxidative stress injury by regulating the Notch pathway

Acute myocardial infarction has increasingly become a global health problem and is a primary cause of cardiovascular disease-related death. Although long noncoding RNAs have been reported to play an important role in various cardiovascular diseases, their protective effects on cardiomyocytes against reactive oxygen species-induced oxidative injury have nonetheless been poorly studied. The present study aims to explore the effect of a novel long noncoding RNA, NONHSAT098487.2, on cardiomyocyte injury induced by H2O2. The expression of NONHSAT098487.2 and pathway-related genes was evaluated by quantitative real-time polymerase chain reaction. Cell viability, release of lactate dehydrogenase, and apoptosis levels were detected by cell counting kit-8, lactate dehydrogenase release assay, and flow cytometry analysis, respectively. The protein levels were estimated by western blotting. The results showed that NONHSAT098487.2 was expressed at a high level in peripheral blood mononuclear cells from acute myocardial infarction patients, which showed a positive correlation with the HS-TnT and CK-MB levels of patients. Furthermore, it is also upregulated in human AC16 cardiomyocytes treated with H2O2 or exposed to hypoxia/reoxygenation conditions. Knockdown of NONHSAT098487.2 restrained the Notch signalling pathway and aggravated H2O2-induced cardiomyocyte oxidative stress injury. In contrast, overexpression of NONHSAT098487.2 activated the Notch signalling pathway and suppressed H2O2-induced oxidative stress injury. However, the Notch inhibitor DAPT weakened the protective effects of NONHSAT098487.2. Therefore, the novel lncRNA NONHSAT098487.2 may play a role in protecting cardiomyocytes from oxidative stress injury by regulating the Notch pathway.

Fine-mapping of retinal vascular complexity loci identifies Notch regulation as a shared mechanism with myocardial infarction outcomes

There is increasing evidence that the complexity of the retinal vasculature measured as fractal dimension, Df, might offer earlier insights into the progression of coronary artery disease (CAD) before traditional biomarkers can be detected. This association could be partly explained by a common genetic basis; however, the genetic component of Df is poorly understood. We present a genome-wide association study (GWAS) of 38,000 individuals with white British ancestry from the UK Biobank aimed to comprehensively study the genetic component of Df and analyse its relationship with CAD. We replicated 5 Df loci and found 4 additional loci with suggestive significance (P < 1e-05) to contribute to Df variation, which previously were reported in retinal tortuosity and complexity, hypertension, and CAD studies. Significant negative genetic correlation estimates support the inverse relationship between Df and CAD, and between Df and myocardial infarction (MI), one of CAD's fatal outcomes. Fine-mapping of Df loci revealed Notch signalling regulatory variants supporting a shared mechanism with MI outcomes. We developed a predictive model for MI incident cases, recorded over a 10-year period following clinical and ophthalmic evaluation, combining clinical information, Df, and a CAD polygenic risk score. Internal cross-validation demonstrated a considerable improvement in the area under the curve (AUC) of our predictive model (AUC = 0.770 ± 0.001) when comparing with an established risk model, SCORE, (AUC = 0.741 ± 0.002) and extensions thereof leveraging the PRS (AUC = 0.728 ± 0.001). This evidences that Df provides risk information beyond demographic, lifestyle, and genetic risk factors. Our findings shed new light on the genetic basis of Df, unveiling a common control with MI, and highlighting the benefits of its application in individualised MI risk prediction.

Transcriptomic Profiling Unravels Novel Deregulated Gene Signatures Associated with Acute Myocardial Infarction: A Bioinformatics Approach

Acute myocardial infarction (AMI) is a severe disease with elevated morbidity and mortality rate worldwide. This is attributed to great losses of cardiomyocytes, which can trigger the alteration of gene expression patterns. Although several attempts have been made to assess the AMI biomarkers, to date their role in rescuing myocardial injury remains unclear. Therefore, the current study investigated three independent microarray-based gene expression datasets from AMI patients (n = 85) and their age-sex-matched healthy controls (n = 70), to identify novel gene signatures that might be involved in cardioprotection. The differentially expressed genes (DEGs) were analyzed using 'GEO2R', and weighted gene correlation network analysis (WGCNA) was performed to identify biomarkers/modules. We found 91 DEGs, of which the number of upregulated and downregulated genes were 22 and 5, respectively. Specifically, we found that the deregulated genes such as ADOR-A3, BMP6, VPS8, and GPx3, may be associated with AMI. WGCNA revealed four highly preserved modules among all datasets. The 'Enrichr' unveiled the presence of miR-660 and STAT1, which is known to affect AMI severity. Conclusively, these genes and miRNA might play a crucial role the rescue of cardiomyocytes from severe damage, which could be helpful in developing appropriate therapeutic strategies for the management of AMI.

mRNA therapy for myocardial infarction: A review of targets and delivery vehicles

Cardiovascular diseases are the leading cause of death in the world. This is partly due to the low regenerative capacity of adult hearts. mRNA therapy is a promising approach under development for cardiac diseases. In mRNA therapy, expression of the target protein is modulated by delivering synthetic mRNA. mRNA therapy benefits cardiac regeneration by increasing cardiomyocyte proliferation, reducing fibrosis, and promoting angiogenesis. Because mRNA is translated in the cytoplasm, the delivery efficiency of mRNA into the cytoplasm and nucleus significantly affects its therapeutic efficacy. To improve delivery efficiency, non-viral vehicles such as lipid nanoparticles have been developed. Non-viral vehicles can protect mRNA from enzymatic degradation and facilitate the cellular internalization of mRNA. In addition to non-viral vehicles, viral vectors have been designed to deliver mRNA templates into cardiac cells. This article reviews lipid nanoparticles, polymer nanoparticles, and viral vectors that have been utilized to deliver mRNA into the heart. Because of the growing interest in lipid nanoparticles, recent advances in lipid nanoparticles designed for cardiac mRNA delivery are discussed. Besides, potential targets of mRNA therapy for myocardial infarction are discussed. Gene therapies that have been investigated in patients with cardiac diseases are analyzed. Reviewing mRNA therapy from a clinically relevant perspective can reveal needs for future investigations.

Photoresponsive Hydrogel-Coated Upconversion Cyanobacteria Nanocapsules for Myocardial Infarction Prevention and Treatment

Myocardial infarction (MI) is a common disease that seriously threatens human health. It is noteworthy that oxygen is one of the key factors in the regulation of MI pathology procession: the controllable hypoxic microenvironment can enhance the tolerance of cardiac myocytes (CMs) and oxygen therapy regulates the immune microenvironment to repair the myocardial injury. Thus, the development of an oxygen-controllable treatment is critically important to unify MI prevention and timely treatment. Here, a hydrogel encapsulated upconversion cyanobacterium nanocapsule for both MI prevention and treatment is successfully synthesized. The engineered cyanobacteria can consume oxygen via respiration to generate a hypoxic microenvironment, resulting in the upregulation of heat shock protein70 (HSP70), which can enhance the tolerance of CMs for MI. When necessary, under 980 nm near-infrared (NIR) irradiation, the system releases photosynthetic oxygen through upconversion luminescence (UCL) to inhibit macrophage M1 polarization, and downregulates pro-inflammatory cytokines IL-6 and tumor necrosis factor-α (TNF-α), thereby repairing myocardial injury. To sum up, a photoresponsive upconversion cyanobacterium nanocapsule is developed, which can achieve MI prevention and treatment for only one injection via NIR-defined respiration and photosynthesis.

LncRNA-ZFAS1 Promotes Myocardial Ischemia-Reperfusion Injury Through DNA Methylation-Mediated Notch1 Down-Regulation in Mice

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The increase of ZFAS1 expression in MIRI is an important cause of cardiomyocyte apoptosis and ROS production.

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ZFAS1 can directly interact with the promoter region of Notch1, recruit DNMT3b to promote DNA methylation in the promoter region of Notch1, and trigger cardiomyocyte apoptosis and ROS production after MIRI.

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Nicotinamide mononucleotide has the potential to attenuate the apoptosis of cardiomyocytes after MIRI by competitively binding to DNMT3b and inhibiting the DNA methylation of Notch1.

The most devastating and catastrophic deterioration of myocardial ischemia-reperfusion injury (MIRI) is cardiomyocyte death. Here we aimed to evaluate the role of lncRNA-ZFAS1 in MIRI and delineate its mechanism of action. The level of lncRNA-ZFAS1 was elevated in MIRI hearts, and artificial knockdown of lncRNA-ZFAS1 in mice improved cardiac function. Notch1 is a potential target of lncRNA-ZFAS1, and lncRNA-ZFAS1 could bind to the promoter region of Notch1 and recruit DNMT3b to induce Notch1 methylation. Nicotinamide mononucleotide could promote the expression of Notch1 by competitively inhibiting the expression of DNMT3b and improving the apoptosis of cardiomyocytes and cardiac function.

Mechanisms of Regenerative Potential Activation in Cardiac Mesenchymal Cells

Recovery of the contractile function of the heart and the regeneration of the myocardium after ischemic injury are contemporary issues in regenerative medicine and cell biology. This study aimed to analyze early transcriptional events in cardiac tissue after infarction and to explore the cell population that can be isolated from myocardial tissue. We induced myocardial infarction in Wistar rats by permanent ligation of the left coronary artery and showed a change in the expression pattern of Notch-associated genes and Bmp2/Runx2 in post-MI tissues using RNA sequencing and RT-PCR. We obtained primary cardiac mesenchymal cell (CMC) cultures from postinfarction myocardium by enzymatic dissociation of tissues, which retained part of the activation stimulus and had a pronounced proliferative potential, assessed using a “xCELLigence” real-time system. Hypoxia in vitro also causes healthy CMCs to overexpress Notch-associated genes and Bmp2/Runx2. Exogenous activation of the Notch signaling pathway by lentiviral transduction of healthy CMCs resulted in a dose-dependent activation of the Runx2 transcription factor but did not affect the activity of the Bmp2 factor. Thus, the results of this study showed that acute hypoxic stress could cause short-term activation of the embryonic signaling pathways Notch and Bmp in CMCs, and this interaction is closely related to the processes of early myocardial remodeling after a heart attack. The ability to correctly modulate and control the corresponding signals in the heart can help increase the regenerative capacity of the myocardium before the formation of fibrotic conditions.

Signaling pathways and targeted therapy for myocardial infarction

Although the treatment of myocardial infarction (MI) has improved considerably, it is still a worldwide disease with high morbidity and high mortality. Whilst there is still a long way to go for discovering ideal treatments, therapeutic strategies committed to cardioprotection and cardiac repair following cardiac ischemia are emerging. Evidence of pathological characteristics in MI illustrates cell signaling pathways that participate in the survival, proliferation, apoptosis, autophagy of cardiomyocytes, endothelial cells, fibroblasts, monocytes, and stem cells. These signaling pathways include the key players in inflammation response, e.g., NLRP3/caspase-1 and TLR4/MyD88/NF-κB; the crucial mediators in oxidative stress and apoptosis, for instance, Notch, Hippo/YAP, RhoA/ROCK, Nrf2/HO-1, and Sonic hedgehog; the controller of myocardial fibrosis such as TGF-β/SMADs and Wnt/β-catenin; and the main regulator of angiogenesis, PI3K/Akt, MAPK, JAK/STAT, Sonic hedgehog, etc. Since signaling pathways play an important role in administering the process of MI, aiming at targeting these aberrant signaling pathways and improving the pathological manifestations in MI is indispensable and promising. Hence, drug therapy, gene therapy, protein therapy, cell therapy, and exosome therapy have been emerging and are known as novel therapies. In this review, we summarize the therapeutic strategies for MI by regulating these associated pathways, which contribute to inhibiting cardiomyocytes death, attenuating inflammation, enhancing angiogenesis, etc. so as to repair and re-functionalize damaged hearts.

Cardiac developmental toxicity and transcriptome analyses of zebrafish (Danio rerio) embryos exposed to Mancozeb

Mancozeb (MZ), an antibacterial pesticide, has been linked to reproductive toxicity, neurotoxicity, and endocrine disruption. However, whether MZ has cardiactoxicity is unclear. In this study, the cardiotoxic effects of exposure to environment-related MZ concentrations ranging from 1.88 μM to 7.52 μM were evaluated at the larval stage of zebrafish. Transcriptome sequencing predicted the mechanism of MZ-induced cardiac developmental toxicity in zebrafish by enrichment analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO). Consistent with morphological changes, the osm, pfkfb3, foxh1, stc1, and nrarpb genes may effect normal development of zebrafish heart by activating NOTCH signaling pathways, resulting in pericardial edema, myocardial fibrosis, and congestion in the heart area. Moreover, differential gene expression analysis indicated that cyp-related genes (cyp1c2 and cyp3c3) were significantly upregulated after MZ treatment, which may be related to apoptosis of myocardial cells. These results were verified by real-time quantitative RT-qPCR and acridine orange staining. Our findings suggest that MZ-mediated cardiotoxic development of zebrafish larvae may be related to the activation of Notch and apoptosis-related signaling pathways.

Targeting cardiomyocyte proliferation as a key approach of promoting heart repair after injury

Cardiovascular diseases such as myocardial infarction (MI) is a major contributor to human mortality and morbidity. The mammalian adult heart almost loses its plasticity to appreciably regenerate new cardiomyocytes after injuries, such as MI and heart failure. The neonatal heart exhibits robust proliferative capacity when exposed to varying forms of myocardial damage. The ability of the neonatal heart to repair the injury and prevent pathological left ventricular remodeling leads to preserved or improved cardiac function. Therefore, promoting cardiomyocyte proliferation after injuries to reinitiate the process of cardiomyocyte regeneration, and suppress heart failure and other serious cardiovascular problems have become the primary goal of many researchers. Here, we review recent studies in this field and summarize the factors that act upon the proliferation of cardiomyocytes and cardiac repair after injury and discuss the new possibilities for potential clinical treatment strategies for cardiovascular diseases.

Adding a "Notch" to Cardiovascular Disease Therapeutics: A MicroRNA-Based Approach

Dysregulation of the Notch pathway is implicated in the pathophysiology of cardiovascular diseases (CVDs), but, as of today, therapies based on the re-establishing the physiological levels of Notch in the heart and vessels are not available. A possible reason is the context-dependent role of Notch in the cardiovascular system, which would require a finely tuned, cell-specific approach. MicroRNAs (miRNAs) are short functional endogenous, non-coding RNA sequences able to regulate gene expression at post-transcriptional levels influencing most, if not all, biological processes. Dysregulation of miRNAs expression is implicated in the molecular mechanisms underlying many CVDs. Notch is regulated and regulates a large number of miRNAs expressed in the cardiovascular system and, thus, targeting these miRNAs could represent an avenue to be explored to target Notch for CVDs. In this Review, we provide an overview of both established and potential, based on evidence in other pathologies, crosstalks between miRNAs and Notch in cellular processes underlying atherosclerosis, myocardial ischemia, heart failure, calcification of aortic valve, and arrhythmias. We also discuss the potential advantages, as well as the challenges, of using miRNAs for a Notch-based approach for the diagnosis and treatment of the most common CVDs.

Nrf2 for cardiac protection: pharmacological options against oxidative stress

Myocardial ischemia or reperfusion increases the generation of reactive oxygen species (ROS) from damaged mitochondria, NADPH oxidases, xanthine oxidase, and inflammation. ROS can be removed by eight endogenous antioxidant and redox systems, many components of which are expressed under the influence of the activated Nrf2 transcription factor. Transcriptomic profiling, sequencing of Nrf2-bound DNA, and Nrf2 gene knockout studies have revealed the power of Nrf2 beyond the antioxidant and detoxification response, from tissue recovery, repair, and remodeling, mitochondrial turnover, and metabolic reprogramming to the suppression of proinflammatory cytokines. Multifaceted regulatory mechanisms for Nrf2 protein levels or activity have been mapped to its functional domains, Nrf2-ECH homology (Neh)1-7. Oxidative stress activates Nrf2 via nuclear translocation, de novo protein translation, and increased protein stability due to removal of the Kelch-like ECH-associated protein 1 (Keap1) checkpoint, or the inactivation of β-transducin repeat-containing protein (β-TrCP), or Hmg-CoA reductase degradation protein 1 (Hrd1). The promise of small-molecule Nrf2 inducers from natural products or derivatives is discussed here. Experimental evidence is presented to support Nrf2 as a lead target for drug development to further improve the treatment outcome for myocardial infarction (MI).

Induced Cardiomyocyte Proliferation: A Promising Approach to Cure Heart Failure

Unlike some lower vertebrates which can completely regenerate their heart, the human heart is a terminally differentiated organ. Cardiomyocytes lost during cardiac injury and heart failure cannot be replaced due to their limited proliferative capacity. Therefore, cardiac injury generally leads to progressive failure. Here, we summarize the latest progress in research on methods to induce cardiomyocyte cell cycle entry and heart repair through the alteration of cardiomyocyte plasticity, which is emerging as an effective strategy to compensate for the loss of functional cardiomyocytes and improve the impaired heart functions.

Interferon Regulatory Factor-2 Binding Protein 2 Ameliorates Sepsis-Induced Cardiomyopathy via AMPK-Mediated Anti-Inflammation and Anti-Apoptosis

Cardiomyopathy commonly occurs after sepsis and is closely associated with high mortality in clinic. Interferon regulatory factor-2 binding protein 2 (IRF2BP2) has been identified as a negative regulator of inflammation, but its role in septic cardiomyopathy is unknown. The current study aims to illuminate the regulatory function of IRF2BP2 on sepsis-induced cardiomyopathy and to explore the underlying mechanisms. Protein expression of IRF2BP2 in response to sepsis-induced cardiomyopathy was examined in the heart of mice challenged by LPS intraperitoneal injection. AAV9-delivered IRF2BP2 overexpression in the heart was applied to evaluate the regulatory role of IRF2BP2 in sepsis-induced myocardial depression, inflammatory response, and cell death. The molecular mechanisms underlying IRF2BP2-regulated cardiomyopathy were explored using western blot screening assay. Primary cardiomyocytes have been isolated to further confirm the role and mechanism of IRF2BP2 during septic cardiomyopathy. IRF2BP2 expression was dramatically increased in the heart of mice after LPS administration. AAV9-mediated IRF2BP2 overexpression significantly improved sepsis-induced cardiac dysfunction, inhibited inflammatory cell infiltration and cytokine production, and blocked cell death after LPS treatment. Mechanistically, IRF2BP2 activated AMPK signaling in cardiomyocytes, while inhibiting AMPK activation largely reversed IRF2BP2-benefited inflammatory suppression and cell survival. These findings clearly demonstrated that IRF2BP2 is a potent suppressor of sepsis-induced myocardial depression and related heart impairment. Targeting IRF2BP2 represents a promising therapeutic strategy for septic cardiomyopathy.

Notch signaling is involved in the antiapoptotic effects of liraglutide on rat H9c2 cardiomyocytes exposed to hypoxia followed by reoxygenation

OBJECTIVE

Liraglutide (Lir) protects cardiomyocytes against high glucose-induced myocardial damage. This study investigated whether Notch signaling participated in the antiapoptotic effects of Lir on rat H9c2 cardiomyocytes subjected to hypoxia followed by reoxygenation (H/R).

METHODS

We used H9c2 rat cardiomyocytes as a model of H/R and measured viability, apoptosis, and expression of the apoptotic genes Bax and Bcl-2 and Notch signaling genes Notch1 and Jagged1. Notch1 was depleted by siRNA to test the effect of Notch1 deficiency on the antiapoptotic effects of Lir on H/R-treated H9c2 cardiomyocytes.

RESULTS

After H/R treatment, viability was significantly decreased, and the apoptosis rate was greater in the H/R group than in the control (CT). Lir at 50, 100, and 200 nM significantly increased viability and decreased apoptosis in H/R-treated H9c2 cells. Treatment with 50 nM Lir for 2 hours before H/R significantly increased the expression levels of Notch1, Jagged1, and Bcl-2 compared with the CT levels. Bax was downregulated, which indicated that Lir activated Notch signaling and inhibited apoptosis. Notch1 depletion partially abolished the antiapoptotic effect of Lir on H/R-treated H9c2 cells by altering apoptotic gene expression.

CONCLUSION

Lir activated Notch signaling, which was responsible for the antiapoptotic effect of Lir on H9c2 cardiomyocytes.

The interaction of Notch and Wnt signaling pathways in vertebrate regeneration

Regeneration is an evolutionarily conserved process in animal kingdoms, however, the regenerative capacities differ from species and organ/tissues. Mammals possess very limited regenerative potential to replace damaged organs, whereas non-mammalian species usually have impressive abilities to regenerate organs. The regeneration process requires proper spatiotemporal regulation from key signaling pathways. The canonical Notch and Wnt signaling pathways, two fundamental signals guiding animal development, have been demonstrated to play significant roles in the regeneration of vertebrates. In recent years, increasing evidence has implicated the cross-talking between Notch and Wnt signals during organ regeneration. In this review, we summarize the roles of Notch signaling and Wnt signaling during several representative organ regenerative events, emphasizing the functions and molecular bases of their interplay in these processes, shedding light on utilizing these two signaling pathways to enhance regeneration in mammals and design legitimate therapeutic strategies.

Regulation of cardiomyocyte fate plasticity: a key strategy for cardiac regeneration

With the high morbidity and mortality rates, cardiovascular diseases have become one of the most concerning diseases worldwide. The heart of adult mammals can hardly regenerate naturally after injury because adult cardiomyocytes have already exited the cell cycle, which subseqently triggers cardiac remodeling and heart failure. Although a series of pharmacological treatments and surgical methods have been utilized to improve heart functions, they cannot replenish the massive loss of beating cardiomyocytes after injury. Here, we summarize the latest research progress in cardiac regeneration and heart repair through altering cardiomyocyte fate plasticity, which is emerging as an effective strategy to compensate for the loss of functional cardiomyocytes and improve the impaired heart functions. First, residual cardiomyocytes in damaged hearts re-enter the cell cycle to acquire the proliferative capacity by the modifications of cell cycle-related genes or regulation of growth-related signals. Additionally, non-cardiomyocytes such as cardiac fibroblasts, were shown to be reprogrammed into cardiomyocytes and thus favor the repair of damaged hearts. Moreover, pluripotent stem cells have been shown to transform into cardiomyocytes to promote heart healing after myocardial infarction (MI). Furthermore, in vitro and in vivo studies demonstrated that environmental oxygen, energy metabolism, extracellular factors, nerves, non-coding RNAs, etc. play the key regulatory functions in cardiac regeneration. These findings provide the theoretical basis of targeting cellular fate plasticity to induce cardiomyocyte proliferation or formation, and also provide the clues for stimulating heart repair after injury.

Oestrogen Receptor β Activation Protects Against Myocardial Infarction via Notch1 Signalling

Purpose

Oestrogen receptor β is believed to exert a cardioprotective effect against ischaemic injury. Nonetheless, the mechanism underlying its protective action remains to be fully elucidated. Recently, increased attention has been focused on Notch1 signalling for ameliorating cardiac ischaemic injury. Here, we hypothesised that oestrogen receptor β activation attenuates myocardial infarction (MI)-induced cardiac damage by modulating the Notch1 signalling pathway.

Methods

Male C57BL/6 mice were used to establish an MI model through the ligation of the anterior descending branch of the left coronary artery. Two chemical drugs, 2,3-Bis(4-hydroxyphenyl)-propionitrile (DPN) and N-[N-(3,5-difluorophenacetyl)-l-alanyl]-s-phenylglycine t-butyl ester (DAPT), a specific inhibitor of Notch1 signalling) were administered via intraperitoneal injection to change oestrogen receptor β and Notch1 activities. Immunohistochemistry, western blot analysis, enzyme-linked immunosorbent assay (Elisa) assessment and echocardiography were used in this study to analyse cardiac oxidative stress, apoptosis, infraction volume, fibrosis and cardiac function.

Results

DPN-mediated oestrogen receptor β activation effectively protected cardiomyocytes from MI-induced oxidative damage and apoptosis. Furthermore, oestrogen receptor β activation reduced the infarct size and lowered the levels of myocardial enzymes in the serum, thereby leading to greater overall cardiac function improvement. Ischaemic injury–induced myocardial fibrosis was attenuated by oestrogen receptor β activation. Nevertheless, all of these cardioprotective effects of oestrogen receptor β activation were almost abrogated by DAPT administration, i.e. DAPT attenuated the anti-oxidative and anti-apoptotic effects and the decrease in infarct and fibrotic areas and reversed cardiac functional recovery. The levels of phospho-phosphatidylinositol-3-kinase (PI3K) and phospho-protein kinase B (Akt) were increased after DPN administration, and this change was reversed after DAPT was administered.

Conclusions

All of these new findings indicate that oestrogen receptor β activation is effective in ameliorating MI-induced cardiac dysfunction by enhancing Notch1 signalling and that PI3K/Akt signalling is the downstream mediator.

Electronic supplementary material

The online version of this article (10.1007/s10557-020-06949-3) contains supplementary material, which is available to authorized users.

MicroRNA-375 overexpression disrupts cardiac development of Zebrafish (Danio rerio) by targeting notch2

MicroRNAs are small noncoding RNAs that are important for proper cardiac development. In our previous study of fetuses with ventricular septal defects, we discovered that microRNA-375 (miR-375) is obviously upregulated compared with that in healthy controls. Our study also confirmed that miR-375 is crucial for cardiomyocyte differentiation. This research mainly focused on the biological significance and mechanism of miR-375 using a zebrafish model. We injected zebrafish embryos with 1-2 nl of a miR-375 mimic at various concentrations (0/2/4/8 μM) or with negative control. The deformation and mortality rates were separately assessed. The different expression levels of miR-375 and related genes were examined by qRT-PCR, and luciferase assays and in situ hybridization were used to clarify the mechanism of miR-375 during embryonic development. Overexpression of miR-375 disrupted the cardiac development of zebrafish embryos. Disruption of miR-375 led to a decreased heart rate, pericardial edema, and abnormal cardiac looping. Various genes involved in cardiac development were downregulated due to the overexpression of miR-375. Moreover, the NOTCH signaling pathway was affected, and the luciferase reporter gene assays confirmed notch2, which was predicted by bioinformatics analysis, as the target gene of miR-375. Our findings demonstrated that the overexpression of miR-375 is detrimental to embryonic development, including cardiac development, and can partially simulate a multisystemic disorder. MiR-375 has an important role during cardiac morphogenesis of zebrafish embryos by targeting notch2, indicating its potential as a diagnostic marker.

Delta-1 Functionalized Hydrogel Promotes hESC-Cardiomyocyte Graft Proliferation and Maintains Heart Function Post-Injury

Current cell transplantation techniques are hindered by small graft size, requiring high cell doses to achieve therapeutic cardiac remuscularization. Enhancing the proliferation of transplanted human embryonic stem cell-derived cardiomyocytes (hESC-CMs) could address this, allowing an otherwise subtherapeutic cell dose to prevent disease progression after myocardial infarction. In this study, we designed a hydrogel that activates Notch signaling through 3D presentation of the Notch ligand Delta-1 to use as an injectate for transplanting hESC-CMs into the infarcted rat myocardium. After 4 weeks, hESC-CM proliferation increased 2-fold and resulted in a 3-fold increase in graft size with the Delta-1 hydrogel compared to controls. To stringently test the effect of Notch-mediated graft expansion on long-term heart function, a normally subtherapeutic dose of hESC-CMs was implanted into the infarcted myocardium and cardiac function was evaluated by echocardiography. Transplantation of the Delta-1 hydrogel + hESC-CMs augmented heart function and was significantly higher at 3 months compared to controls. Graft size and hESC-CM proliferation were also increased at 3 months post-implantation. Collectively, these results demonstrate the therapeutic approach of a Delta-1 functionalized hydrogel to reduce the cell dose required to achieve functional benefit after myocardial infarction by enhancing hESC-CM graft size and proliferation.

Extracellular Vesicles From Notch Activated Cardiac Mesenchymal Stem Cells Promote Myocyte Proliferation and Neovasculogenesis

Cardiac mesenchymal stem cells (C-MSCs) are a novel mesenchymal stem cell (MSC) subpopulation derived from cardiac tissue, which are reported to be responsible for cardiac regeneration. Notch signaling is believed to aid in cardiac repair following myocardial injury. In this study, we have investigated the role of extracellular vesicles (EVs) from Notch1 engineered C-MSCs on angiogenesis and cardiomyocyte (CM) proliferation in ischemic myocardium. C-MSCs were isolated from Notch1^flox mice (C-MSC^{Notch1 FF}). Notch1 gene deletion was accomplished by adenoviral vector-mediated Cre recombination, and Notch1 overexpression was achieved by overexpression of Notch1 intracellular domain (N1ICD). EVs were isolated by using the size exclusion column method. Proteomic composition of EV was carried out by mass spectrometry. A mouse myocardial infarction (MI) model was generated by permanent left anterior descending (LAD) coronary artery ligation. Intramyocardial transplantation of Notch1 knockout C-MSCs (C-MSCs^{Notch1 KO}) did not have any effect on cardiac function and scar size. On the other hand, transplantation of N1ICD-overexpressing C-MSCs (C-MSCs^N1ICD) showed significant improvement in cardiac function and attenuation of fibrosis as compared to the control (PBS) group and non-modified C-MSC groups. C-MSCs^N1ICD differentiated into smooth muscle cells and formed new vessels. Proteomics profiling identified several proteins, such as lysyl oxidase homolog-2 and biglycan, as highly enriched proteins in EV-C-MSCs^N1ICD. Go term analysis indicated that EV-C-MSCs^N1ICD were enriched with bioactive factors, potent pro-repair proteins responsible for cell migration and proliferation. EV-C-MSCs^Notch1FF and EV-C-MSCs^N1ICD were strongly proangiogenic under both in vitro and in vivo conditions. EV-C-MSCs^N1ICD caused dense tube formation in vitro and increased neovasculogenesis in the peri-infarct area in vivo. Furthermore, EV-C-MSCs^N1ICD attenuated endothelial cell (EC) and CM apoptosis under oxidative stress and ischemic injury. Similarly, EV-C-MSC^{Notch1 FF} and EV-C-MSC^N1ICD treatment improved cardiac function and decreased fibrosis in mice post-MI. EV-C-MSCs^N1ICD were very effective in improving cardiac function and decreasing fibrosis. Notch1 signaling is a strong stimulus for cardiac regeneration by C-MSCs. EVs secreted by Notch1-overexpressing C-MSCs were highly effective in preventing cell death, promoting angiogenesis and CM proliferation, and restoring cardiac function post-MI. Overall, these results suggest that Notch1 overexpression may further enhance the effectiveness of EVs secreted by C-MSCs in cell-free therapy.

Interventions in WNT Signaling to Induce Cardiomyocyte Proliferation: Crosstalk with Other Pathways

Myocardial infarction is a frequent cardiovascular event and a major cause for cardiomyocyte loss. In adult mammals, cardiomyocytes are traditionally considered to be terminally differentiated cells, unable to proliferate. Therefore, the wound-healing response in the infarct area typically yields scar tissue rather than newly formed cardiomyocytes. In the last decade, several lines of evidence have challenged the lack of proliferative capacity of the differentiated cardiomyocyte: studies in zebrafish and neonatal mammals have convincingly demonstrated the regenerative capacity of cardiomyocytes. Moreover, multiple signaling pathways have been identified in these models that-when activated in adult mammalian cardiomyocytes-can reactivate the cell cycle in these cells. However, cardiomyocytes frequently exit the cell cycle before symmetric division into daughter cells, leading to polyploidy and multinucleation. Now that there is more insight into the reactivation of the cell cycle machinery, other prerequisites for successful symmetric division of cardiomyocytes, such as the control of sarcomere disassembly to allow cytokinesis, require more investigation. This review aims to discuss the signaling pathways involved in cardiomyocyte proliferation, with a specific focus on wingless/int-1 protein signaling. Comparing the conflicting results from in vitro and in vivo studies on this pathway illustrates that the interaction with other cells and structures around the infarct is likely to be essential to determine the outcome of these interventions. The extensive crosstalk with other pathways implicated in cardiomyocyte proliferation calls for the identification of nodal points in the cell signaling before cardiomyocyte proliferation can be moved forward toward clinical application as a cure of cardiac disease. SIGNIFICANCE STATEMENT: Evidence is mounting that proliferation of pre-existing cardiomyocytes can be stimulated to repair injury of the heart. In this review article, an overview is provided of the different signaling pathways implicated in cardiomyocyte proliferation with emphasis on wingless/int-1 protein signaling, crosstalk between the pathways, and controversial results obtained in vitro and in vivo.

Preactivation of Notch1 in remote ischemic preconditioning reduces cerebral ischemia-reperfusion injury through crosstalk with the NF-κB pathway

Background

Remote ischemic preconditioning (RIPC) initiates endogenous protective pathways in the brain from a distance and represents a new, promising paradigm in neuroprotection against cerebral ischemia-reperfusion (I/R) injury. However, the underlying mechanism of RIPC-mediated cerebral ischemia tolerance is complicated and not well understood. We reported previously that preactivation of Notch1 mediated the neuroprotective effects of cerebral ischemic preconditioning in rats subjected to cerebral I/R injury. The present study seeks to further explore the role of crosstalk between the Notch1 and NF-κB signaling pathways in the process of RIPC-induced neuroprotection.

Methods

Middle cerebral artery occlusion and reperfusion (MCAO/R) in adult male rats and oxygen-glucose deprivation and reoxygenation (OGD/R) in primary hippocampal neurons were used as models of I/R injury in vivo and in vitro, respectively. RIPC was induced by a 3-day procedure with 4 cycles of 5 min of left hind limb ischemia followed by 5 min of reperfusion each day before MCAO/R. Intracerebroventricular DAPT injection and sh-Notch1 lentivirus interference were used to inhibit the Notch1 signaling pathway in vivo and in vitro, respectively. After 24 h of reperfusion, neurological deficit scores, infarct volume, neuronal apoptosis, and cell viability were assessed. The protein expression levels of NICD, Hes1, Phospho-IKKα/β (p-IKK α/β), Phospho-NF-κB p65 (p-NF-κB p65), Bcl-2, and Bax were assessed by Western blotting.

Results

RIPC significantly improved neurological scores and reduced infarct volume and neuronal apoptosis in rats subjected to I/R injury. OGD preconditioning significantly reduced neuronal apoptosis and improved cell viability after I/R injury on days 3 and 7 after OGD/R. However, the neuroprotective effect was reversed by DAPT in vivo and attenuated by Notch1-RNAi in vitro. RIPC significantly upregulated the expression of proteins related to the Notch1 and NF-κB pathways. NF-κB signaling pathway activity was suppressed by a Notch1 signaling pathway inhibitor and Notch1-RNAi.

Conclusions

The neuroprotective effect of RIPC against cerebral I/R injury was associated with preactivation of the Notch1 and NF-κB pathways in neurons. The NF-κB pathway is a downstream target of the Notch1 pathway in RIPC and helps protect focal cerebral I/R injury.

Notch and interacting signalling pathways in cardiac development, disease, and regeneration

Cardiogenesis is a complex developmental process involving multiple overlapping stages of cell fate specification, proliferation, differentiation, and morphogenesis. Precise spatiotemporal coordination between the different cardiogenic processes is ensured by intercellular signalling crosstalk and tissue-tissue interactions. Notch is an intercellular signalling pathway crucial for cell fate decisions during multicellular organismal development and is aptly positioned to coordinate the complex signalling crosstalk required for progressive cell lineage restriction during cardiogenesis. In this Review, we describe the role of Notch signalling and the crosstalk with other signalling pathways during the differentiation and patterning of the different cardiac tissues and in cardiac valve and ventricular chamber development. We examine how perturbation of Notch signalling activity is linked to congenital heart diseases affecting the neonate and adult, and discuss studies that shed light on the role of Notch signalling in heart regeneration and repair after injury.

A Supramolecular Platform for the Introduction of Fc-Fusion Bioactive Proteins on Biomaterial Surfaces

Bioorthogonal chemistry is an excellent method for functionalization of biomaterials with bioactive molecules, as it allows for decoupling of material processing and bioactivation. Here, we report on a modular system created by means of tetrazine/trans-cyclooctene (Tz/TCO) click chemistry undergoing an inverse electron demand Diels-Alder cycloaddition. A reactive supramolecular surface based on ureido-pyrimidinones (UPy) is generated via a UPy-Tz additive, in order to introduce a versatile TCO-protein G conjugate for immobilization of Fc-fusion proteins. As a model bioactive protein, we introduced Fc-Jagged1, a Notch ligand, to induce Notch signaling activity on the material. Interestingly, HEK293 FLN1 cells expressing the Notch1 receptor were repelled by films modified with TCO-protein G but adhered and spread on functionalized electrospun meshes. This indicates that the material processing method influences the biocompatibility of the postmodification. Notch signaling activity was upregulated 5.6-fold with respect to inactive controls on electrospun materials modified with TCO-protein G/Fc-Jagged1. Furthermore, downstream effects of Notch signaling were detected on the gene level in vascular smooth muscle cells expressing the Notch3 receptor. Taken together, our results demonstrate the successful use of a modular supramolecular system for the postprocessing modification of solid materials with functional proteins.

A novel bispecific c-MET/CTLA-4 antibody targetting lung cancer stem cell-like cells with therapeutic potential in human non-small-cell lung cancer

A novel paradigm in tumor biology suggests that non-small-cell lung cancer (NSCLC) growth is driven by lung cancer stem cell (LCSC) like cells, but t here are still not any effective strategies to remove LCSCs. The bispecific antibody (BsAb) is a novel antibody, which can target two different antigens and mediate specific killing effects by selectively redirecting effector cells to the target cells. Here, we designed and synthesized a new BsAb, BsAb-5, that can target cellular mesenchymal-to-epithelial transition factor (c-MET) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) in CD166⁺ LCSCs with high affinity and specificity, for the first time. We showed that BsAb-5 could inhibit hepatocyte growth factor (HGF) mediated tumor development, including proliferation, migration, and apoptosis, serving as an inhibitory c-MET antibody. Moreover, we demonstrated that mechanisms responsible for BsAb-5 in CD166⁺ LCSCs included inducing c-MET degradation and inhibition of HGF-stimulated c-MET-Notch pathway by using AdHGF infection, nuclei location, and Western blot assays. In vivo, xenograft analysis revealed that mice on BsAb-5 group showed significantly reduced tumor volume. At the meantime, the observed antitumor effects of BsAb-5 were dependent on considerably suppressing T-regulatory cells (T_regs) and up-regulating effector T cells. On the basis of these results, we have identified a potential BsAb drug, which can effectively target c-MET and CTLA-4 in CD166⁺ LCSCs for the treatment of human NSCLC.

Reversible Notch1 acetylation tunes proliferative signalling in cardiomyocytes

Aims

The Notch signalling pathway regulates the balance between proliferation and differentiation in several tissues, including the heart. Our previous work has demonstrated that the proliferative potential of neonatal cardiomyocytes relies on Notch1 activity. A deep investigation on the biochemical regulation of the Notch signalling in cardiomyocytes is the focus of the current research.

Methods and results

We show that the Notch1 intracellular domain is acetylated in proliferating neonatal rat cardiomyocytes and that acetylation tightly controls the amplitude and duration of Notch signalling. We found that acetylation extends the half-life of the protein, and enhanced its transcriptional activity, therefore counteracting apoptosis and sustaining cardiomyocyte proliferation. Sirt1 acted as a negative modulator of Notch1 signalling; its overexpression in cardiomyocytes reverted Notch acetylation and dampened its stability. A constitutively acetylated fusion protein between Notch1 and the acetyltransferase domain of p300 promoted cardiomyocyte proliferation, which was remarkably sustained over time. Viral vector-mediated expression of this protein enhanced heart regeneration after apical resection in neonatal mice.

Conclusion

These results identify the reversible acetylation of Notch1 as a novel mechanism to modulate its signalling in the heart and tune the proliferative potential of cardiomyocytes.

Paracrine Mechanisms Involved in Mesenchymal Stem Cell Differentiation into Cardiomyocytes

Cardiovascular Disease (CVD) is one of the world-wide healthcare problem that involves the heart or blood vessels. CVD includes myocardial infarction and coronary artery diseases (CAD). Dysfunctional myocardial cells are leading causes of low cardiac output or ventricular dysfunction after cardiac arrest and may contribute to the progression of CVD which could not generate new cardiomyocytes in human adult heart. The mesenchymal stem cells (MSCs) which are present in adult marrow can self-renew and have the capacity of differentiation into multiple types of cells including cardiomyocytes. Recent biochemical analyses greatly revealed that several regulators of MSCs, such as HGF, PDGF, Wnt, and Notch-1 signaling pathways have been shown to be involved in the proliferation and differentiation into cardiomyocytes. Preclinical studies are paving the way for further applications of MSCs in the repair of myocardial infarction. In this study, we discuss and summarize the paracrine mechanisms involved in MSCs differentiation into cardiomyocytes.

Triggering of a Dll4-Notch1 loop impairs wound healing in diabetes

Diabetic foot ulcerations (DFUs) represent a major medical, social, and economic problem. Therapeutic options are restricted due to a poor understanding of the pathogenic mechanisms. The Notch pathway plays a pivotal role in cell differentiation, proliferation, and angiogenesis, processes that are profoundly disturbed in diabetic wounds. Notch signaling is activated upon interactions between membrane-bound Notch receptors (Notch 1-4) and ligands (Jagged 1-2 and Delta-like 1, 3, 4), resulting in cell-context-dependent outputs. Here, we report that Notch1 signaling is activated by hyperglycemia in diabetic skin and specifically impairs wound healing in diabetes. Local inhibition of Notch1 signaling in experimental wounds markedly improves healing exclusively in diabetic, but not in nondiabetic, animals. Mechanistically, high glucose levels activate a specific positive Delta-like 4 (Dll4)-Notch1 feedback loop. Using loss-of-function genetic approaches, we demonstrate that Notch1 inactivation in keratinocytes is sufficient to cancel the repressive effects of the Dll4-Notch1 loop on wound healing in diabetes, thus making Notch1 signaling an attractive locally therapeutic target for the treatment of DFUs.

Notch signal pathway - therapeutic target for regulation of reparative processes in the heart

Notch signaling pathway is a universal regulator of cell fate in embryogenesis and in maintaining the cell homeostasis of adult tissue. Through local cell-cell interactions, he controls neighboring cells behavior and determines their capacity for self-renewal, growth, survival, differentiation, and apoptosis. Recent studies have shown that the control of regenerative processes in the heart is also carried out with the participation of Notch system. At the heart of Notch regulates migration bone marrow progenitors and stimulates the proliferation of cardiomyocytes, cardiac progenitor cell activity, limits cardiomyocyte hypertrophy and fibrosis progression and stimulates angiogenesis. Notch signaling pathway may be regarded as a very promising target for the development of drugs for the stimulation of regeneration in the myocardium.

Candidate early predictive plasma protein markers of doxorubicin-induced chronic cardiotoxicity in B6C3F1 mice

Cardiotoxicity is a serious adverse effect of doxorubicin (DOX) treatment in cancer patients. Currently, there is a lack of sensitive biomarkers to predict the risk of DOX-induced cardiotoxicity. Using SOMAmer-based proteomic technology, 1129 proteins were profiled to identify potential early biomarkers of cardiotoxicity in plasma from male B6C3F₁ mice given a weekly intravenous dose of 3 mg/kg DOX or saline (SAL) for 2, 3, 4, 6, or 8 weeks (6, 9, 12, 18, or 24 mg/kg cumulative DOX doses, respectively). Also, a group of mice received the cardio-protectant, dexrazoxane (DXZ; 60 mg/kg; intraperitoneal) 30 min before a weekly DOX or SAL dose. Proteomic analysis in plasma collected a week after the last dose showed a significant ≥1.2-fold change in level of 18 proteins in DOX-treated mice compared to SAL-treated counterparts during 8-week exposure. Of these, neurogenic locus notch homolog protein 1 (NOTCH1), von Willebrand factor (vWF), mitochondrial glutamate carrier 2, Wnt inhibitory factor 1, legumain, and mannan-binding lectin serine protease 1 were increased in plasma at 6 mg/kg cumulative DOX dose, prior to the release of myocardial injury marker, cardiac troponin I at 12 mg/kg and higher cumulative doses. These six proteins also remained significantly elevated following myocardial injury or pathology at 24 mg/kg. Pretreatment of mice with DXZ significantly attenuated DOX-induced elevated levels of only NOTCH1 and vWF with mitigation of cardiotoxicity. This suggests NOTCH1 and vWF as candidate early biomarkers of DOX cardiotoxicity, which may help in addressing a clinically important question of identifying cancer patients at risk for cardiotoxicity.