Frontiers in Cardiovascular Medicine

AimArtificial intelligence applied to electrocardiography (AI-ECG) can derive a heart age or ECG-age, potentially reflecting waveform patterns that indicate cumulative myocardial stress. The heart age gap (HA-gap, {Delta}age) is defined as the difference between a persons ECG-age and chronological age. Former studies suggest a threshold of {Delta}age > 8 yrs as a biomarker for accelerated biological age, associated with higher risk for cardiovascular events. In this study, we investigate whether {Delta}age differentiates training-induced physiological from pathological left ventricular remodeling. MethodsAn AI-ECG was applied to 162 resting 12-lead ECGs of each professional footballers, population controls without cardiovascular disease, and patients with systolic heart failure (HF). Explainable AI identified contributing leads and waveforms, and results were compared with established ECG voltage criteria for left ventricular hypertrophy (Sokolow-Lyon, Cornell) and low QRS voltage (LQRSV). ResultsAccelerated HA ({Delta}age,+) was present in 38.9% of athletes, 35.8% of community controls, and 96.9% of HF patients. As a diagnostic criterion, accelerated HA achieved 96.9% sensitivity and 62.7% specificity for distinguishing diseased from healthy cohorts. In contrast, classical ECG voltage criteria showed lower sensitivity (6-17%) but higher specificity (85-100%). Correlation analyses confirmed significant associations of HA-gap with Cornell voltage ({rho} = 0.25, p < 0.001) and LQRSV (limb:{rho} = -0.43, p < 0.001; precordial:{rho} = -0.32, p < 0.001). ConclusionsThe AI-based HA-gap is a multi-factorial marker of ventricular remodeling beyond mass and can separate benign athletic hypertrophy from pathological remodeling with high sensitivity. Incorporating athlete and youth cohorts into model development could further improve specificity to enable future application in preventive and sports cardiology.

BackgroundPhosphodiesterases (PDEs) are the enzymes that hydrolyze cyclic nucleotides (cAMP and cGMP) playing a key role in the homeostasis of these two second messengers. PDE2A is a dual-specific PDE that breaks down both cAMP and cGMP and can be activated by cGMP. It appears peculiar that the Pde2A-deficient (Pde2A-/-) mouse model is embryonically lethal, likely due to a strongly reduced size of liver and to a severe anemia. In addition, the heart of Pde2A-/- embryos shows ventricular and atrial septum defects, hypertrabeculation, heart dilatation and non-compaction defects. We recently highlighted a direct relationship between Pde2A impairment, consequent increase of cAMP and the onset of mouse congenital heart defects (CHDs), however the molecular mechanisms underlining the heart defects remain unknown. MethodsTranscriptome analysis of Pde2A-/- embryonic heart was performed by RNA sequencing and the most altered genes were also analyzed by quantitative real time PCR. In vivo treatment with drugs acting on cAMP signaling (Metoprolol and H89) and oxidative stress (N-Acetyl-Cysteine, NAC) were carried out on pregnant Pde2A+/- female. Histological, biochemical, and molecular analyses were then performed on embryonic hearts. ResultsWe found a significant modulation of more than 500 genes affecting biological processes involved in the immune system, cardiomyocyte development and contractility, angiogenesis, control of gene transcription and oxidative stress in hearts from Pde2A-/- embryos. Metoprolol and H89 administration were able to prevent heart dilatation and hypertabeculation in Pde2A-/-embryos. Metoprolol was also able to partially impede heart septum defect and oxidative stress at tissue and molecular levels. Partial rescue of cardiac defects was observed by using the antioxidant NAC, indicating oxidative stress like one of the molecular mechanisms underpinning the CHDs. ConclusionsWe identified specific biological processes, molecules and cell signaling that can be targeted by selected drugs with consequent beneficial effects for cAMP-dependent CHDs. Novelty and SignificanceO_ST_ABSWhat is Known?C_ST_ABSO_LICongenital Heart Defects are the most frequent heart birth defects including septal defects, hypertrabeculation and non-compacted myocardium. C_LIO_LIPde2A hydrolyses the cAMP and cGMP second messengers. C_LIO_LIPde2A-deficient mice are embryonic lethal and show cAMP-dependent Congenital Heart Defects. C_LI What New Information Does This Article Contribute?O_LIWe identified several novel pathways altered in hearts of Pde2A-/- embryos. C_LIO_LIWe demonstrated that drugs lowering cAMP levels rescued specific CHDs in Pde2A-/- embryos. C_LIO_LIWe discovered that antioxidants are beneficial for CHDs in Pde2A-/- embryos. C_LI The significance of this work relay in molecular discoveries and pharmacological approaches to treat CHDs by using a mouse model that recapitulate the major congenital heart defects. Among the pathways involved in specific defects associated with CHDs, the transcriptome analysis revealed an impairment of genes of the immune system, cardiomyocyte development and contractility, angiogenesis, control of gene transcription and oxidative stress in Pde2A-/- hearts. The scientific community will have open access to the RNA-seq data that can be utilized to further understand the congenital cardiac pathology and clarify the molecular implication in selected defects such as septal and ventricular wall defects. Up to date CHDs, when possible and if identified in time, are mostly treated trough surgery. The identification of drugs blunting the cAMP signaling response or reducing oxidative stress pathways will be useful for setting therapeutic approaches to alleviate CHDs.

BACKGROUNDThe mammalian heart contains cardiac stem cells throughout life, but it has not been possible to harness or stimulate these cells to repair damaged myocardium in vivo. Assuming physiological relevance of these cells, which have evolved and have been maintained throughout evolution, we are investigating their function using mouse cardiac stem cell lines as an in vitro model system. METHODSHere we use genetically modified embryonic stem cells and cardiac stem cells from the mouse as model systems to study the influence of desmin and Secreted Protein Acidic and Rich in Cysteine (SPARC) on cardiomyogenesis in embryoid bodies and cardiac bodies. We analyze their expression in self-renewing and differentiating stem cells by fluorescence microscopy, RT-qPCR, quantitative Western blotting and fluorescence activated cell sorting, and assess their influence on the expression of myocardial transcription factors. RESULTSIn embryoid bodies, desmin induces expression and secretion of SPARC, which promotes cardiomyogenesis. Cardiac stem cells secrete substantial amounts of SPARC, which also promotes cardiomyogenesis in a concentration-dependent, autocrine manner and promotes expression of myocardial transcription factors and desmin. Desmin and SPARC interact genetically and form a positive feedback loop and secreted SPARC negatively influences sparc mRNA expression. Finally, SPARC rescues cardiomyogenic desmin-haploinsufficiency in cardiac stem cells in a glycosylation-dependent manner, increases the phosphorylation of Smad2 and induces the expression of gata4, nkx2.5 and mef2C. CONCLUSIONSDemonstration that desmin-induced autocrine secretion of SPARC in cardiac stem cells promotes cardiomyogenesis raises the possibility that a physiological function of cardiac stem cells in the adult and aging heart may be the gland-like secretion of factors such as SPARC that modulate age-related and adverse environmental influences and thereby contribute to cardiac homeostasis throughout life.

BackgroundPregestational diabetes (PGD) increases congenital heart defect (CHD) risk over five-fold. Maternal exercise enhances endothelial nitric oxide synthase (eNOS) activity, benefiting embryos, though its causal role remains unclear. This study investigated eNOSs role in maternal exercise-mediated protection of fetal heart development in a PGD mouse model. MethodsPGD was induced in eNOS+/- or wild-type (WT) female mice via streptozotocin before breeding with WT or eNOS+/- males. Pregnant females had access to a running wheel for voluntary exercise or remained sedentary. Fetuses were collected at embryonic day (E) 18.5 for genotyping and CHD assessment. E12.5 hearts were analyzed for proliferation, apoptosis, oxidative stress, and eNOS protein levels. ResultsMaternal exercise normalized litter size and mortality rates in offspring of diabetic eNOS+/- females but did not reduce CHD incidence in offspring of WT or eNOS+/- females with PGD. CHDs included septal defects, double outlet right ventricle, and valve defects. Exercise increased coronary artery density but not capillary density. Proliferation deficits at E12.5 were restored by exercise, yet oxidative stress remained elevated. Maternal exercise in eNOS+/- dams during PGD did not significantly change eNOS protein levels in both eNOS+/+ and eNOS+/- fetal hearts. Offspring genotype did not impact CHD incidence, cell proliferation, apoptosis or oxidative stress. ConclusionsMaternal exercise does not prevent CHDs in PGD offspring of eNOS+/- mice. Its ability to mitigate PGD-induced oxidative stress is eNOS-dependent and essential for improving heart morphology. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=178 SRC="FIGDIR/small/647329v1_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@4c9e4forg.highwire.dtl.DTLVardef@2d60fforg.highwire.dtl.DTLVardef@13b2d72org.highwire.dtl.DTLVardef@249a0c_HPS_FORMAT_FIGEXP M_FIG C_FIG

RationaleCardiac organoids (COs) are advanced models for investigating heart development and disease, while require maturation to resemble the structural and functional characteristics of the human heart. ObjectiveThis study reveals the role of Decorin (DCN) contributes to the mature and vascularized COs and assesses the biological mechanism responsible for CO maturation. Methods and ResultsDCN-treated COs exhibit structural maturation involving aligned sarcomere, mitochondria, and t-tubule structures, and vessel formations, as well as functional maturation involving synchronized contraction-relaxation, Ca2+ transient, and increases ion channel expressions. DCN-treated COs also show metabolic maturation, including enhanced fatty acid oxidation and increased mitophagy. Transcriptional profiling results indicate that DCN-treated COs have increased levels of AMPK signaling and mitophagy. In DCN-treated COs, AMPK knockdown affects mitochondrial biogenesis, cardiac metabolism, ion channels, and mitophagy. ConclusionsThese findings indicate that DCN is crucial for development of mature, vascularized COs and that CO maturation is primarily regulated through AMPK signaling, which is triggered by DCN. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=175 SRC="FIGDIR/small/599970v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@1333cfaorg.highwire.dtl.DTLVardef@e842baorg.highwire.dtl.DTLVardef@74ce1corg.highwire.dtl.DTLVardef@87ad38_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGRAPHIC ABSTRACTC_FLOATNO A graphic abstract is available for this article. DCN enhances metabolic maturation in COs by AMPK-triggered regulation of the glycolysis, fatty acid oxidation, and mitophagy. C_FIG

AimLongitudinal global strain (LGS) is reduced in obese patients with normal ejection fraction of the left ventricle. TAPSE/PAPS ratio, recently described, may be a step forward a more efficient RV function evaluation. There are still few publications in the application of these methods in pediatric patients. MethodsThis case-control study compared 104 children aged 5-18 years between October 2017 and February 2019, 52 obese children with body mass index (BMI) > +2 SD, and 52 matched controls. They were screened for other cardiovascular risk factors like insulin resistance or hypercholesterolemia. A complete echocardiography including standard and functional parameters was performed. ResultsWe found that obese children presented poor systolic function (LGS -15,90 {+/-} 3,84 %) in comparison with non-obese children (-19,44 {+/-} 5,75 %, p=0,001). LGS correlated positively with body mass index (BMI). Standard echocardiography also revealed cardiomegaly and hypertrophy. TAPSE/PASP ratio correlated negatively with triglycerides levels ({beta} -0,402, p=0,014). Diastolic function was poor in those with HOMA-IR ({beta} -0,375, p=0,016) and hypertriglyceridemia ({beta} -0,375 p=0,024). ConclusionWe think that is necessary to perform a standarised cardiovascular evaluation in obese children for early identification of subclinical dysfunction especially in those with insulin resistance and dyslipidemia

BackgroundCoronary vessels in embryonic mouse heart arises from multiple progenitor population including sinus venosus (SV), endocardium, and proepicardium. ELA/APJ signaling is shown to regulate coronary growth from SV pathway within the subepicardium, whereas VEGF-A/VEGF-R2 pathways is implicated to regulate coronary growth from endocardium pathway. Our previous study show hypoxia as a potential signaling cue to stimulate overall coronary growth and expansion within the myocardium. However, the role of hypoxia and its downstream signaling pathways in the regulation of coronary vessel development is not known. In this study, we investigated the role of hypoxia in coronary vessel development and have identified SOX17- and VEGF-R2-mediated signaling as a potential downstream pathway of hypoxia in the regulation of coronary vessel development. ResultsWe show that hypoxia gain-of-function in the myocardium through upregulation of HIF-1 disrupts the normal pattern of coronary angiogenesis in developing mouse hearts and displays phenotype that is reminiscent of accelerated coronary growth. We show that VEGF-R2 expression is increased in coronary endothelial cells under hypoxia gain-of-function in vivo and in vitro. Furthermore, we show that SOX17 expression is upregulated in developing mouse heart under hypoxia gain-of-function conditions, whereas SOX17 expression is repressed under hypoxia loss-of-function conditions. Furthermore, our results show that SOX17 loss-of-function disrupts normal pattern of coronary growth. ConclusionCollectively, our data provide strong phenotypic evidence to show that hypoxia might regulate coronary growth in the developing mouse heart potentially through VEGF-R2- and SOX17-mediated downstream signaling pathways.

BackgroundThe adult mammalian heart lacks the regenerative potential required to replenish depleted cardiomyocytes and restore cardiac function after injury. Ischemic cardiac injury contributes to heart failure, a leading cause of death worldwide. Neonatal mice possess the capacity to regenerate injured myocardium and macrophages contribute to this process. The mechanisms contributing to the regenerative crosstalk between macrophages and cardiomyocytes remain incompletely elucidated and offer potential to inform future therapeutic strategies. MethodsTo test the immune contribution during cardiac regeneration, we studied the response to myocardial ischemia in neonatal mice after silencing myeloid hypoxia inducible factor 1 (Hif1) and reconstituting HIF-dependent mitogens. In parallel, we examined epigenetic and transcriptional signatures of the cardiac macrophage response and focused on intercellular crosstalk with cardiomyocytes. ResultsIn myeloid Hif1 deficient mice, cardiac regenerative function was lost after coronary ligation. This manifested through loss of ventricular systolic function and elevated myocardial scarring. HIF1 was found to be activated in resident-type cardiac macrophages after ischemic insult. Hypoxia stimulated macrophages to secrete insulin-like growth factor 1 (IGF-1), and this required Hif1. Parallel multiomic analysis revealed epigenetic regenerative signatures. ConclusionsThe data reveal an age-restricted requirement for myeloid Hif1 in neonatal cardiac regeneration, likely through IGF-1 signaling.

Post-exercise [V]O2 kinetics and [V]O2 recovery delay (RD) are clinical prognostic markers in cardiac patients, but have not been studied after exercise training in patients with coronary heart disease (CHD). We aimed to compare the effects of 12-weeks moderate-intensity continuous exercise training (MICET), low volume high-intensity interval training (LV-HIIT), or combined MICET/HIIT on O2 deficit, post-exercise [V]O2 kinetics, O2 debt and [V]O2 recovery delay (RD) in patients with CHD. MethodsPatients with CHD were randomised in MICET, LV-HIIT or combined MICET/HIIT group for 12 weeks. Cardiopulmonary exercise test (CPET) parameters were assessed, and key exercise variables were calculated during and after exercise. CPET post-exercise kinetics time constant (r) (for [V]O2, [V]CO2,[V] E and HR), O2 deficit, O2 debt and [V]O2 recovery delay (RD) were calculated before and after training. ResultsA significant time effect (training) for r [V]O2 (min) (p<0.05) was shown for all groups. Shorter r [V]O2 values with small effect size (ES: 0.21 to 0.4) were noted for the combined MICET/HIIT and MICET groups. A significant time effect (p<0.01) was noted for O2 debt that was increased after training (ES: 0.1 to 0.47). No significant statistical effect was shown for [V]O2 RD and r [V]CO2, r[V] E, r HR and O2 deficit in all groups. ConclusionsIn patients with CHD, exercise training improved post-exercise [V]O2 kinetic and the O2 debt, with a higher impact of exercise dose (combined MICET/HIIT). Exercise training did not improved the [V]O2 RD or other{tau} CPET recovery variables in CHD patients.

(1) AimsProcollagen C-proteinase enhancer 1 (PCPE-1) is an extracellular matrix protein and a major regulator of fibrillar collagen biosynthesis. Previous work has shown that its abundance is often increased in the context of tissue repair and fibrosis. The present study was designed to evaluate its potential as a biomarker of myocardial interstitial fibrosis (MIF), a well-established pathogenic pathway leading to heart failure. (2) Methods and ResultsCardiac fibrosis was induced in rats using an optimized model of chronic pressure overload triggered by angiotensin II and N{omega}-nitro-L-arginine methyl ester (L-NAME). All treated animals suffered from heart hypertrophy and the increase in heart collagen volume fraction (CVF), evidenced by histology and 68Ga-Collagelin uptake, confirmed the development of cardiac fibrosis. Functional analysis by simultaneous PET-MRI further showed that our model closely reflected the pathological features seen in human MIF, including left ventricle thickening and diastolic dysfunction associated with decreased ejection fraction. PCPE-1 mRNA and protein levels were augmented by factors of 3.4 and 6.1 respectively in the heart tissue of treated rats. Moreover, protein abundance was well-correlated with CVF (r=0.92, p<0.0001) and PCPE-1 immuno-detection mainly localized the protein to fibrotic areas. Finally, PCPE-1 plasma levels measured by ELISA were increased in fibrotic rats compared to controls. (3) ConclusionTogether, our findings demonstrate that PCPE-1 levels in the heart and circulation tightly reflect the cardiac fibrosis status and heart function impairment in rats and suggest that it could be a very useful marker to monitor human heart diseases leading to fibrosis.

BackgroundIschemic heart disease (IHD) has the highest mortality rate in the globe. This returns to the poor diagnostic and therapeutic strategies including the early prevention methods. AimsTo assess the changes in the single channel electrocardiography (SCECG) at rest and on exercise test in patients with vs without IHD confirmed by stress computed tomography myocardial perfusion (CTP) imaging with vasodilatation stress-test. ObjectivesIHD frequently have preventable risk factors and causes that lead to the disease appearance. However, the lack of the proper diagnostic and prevention tools remains a global challenge in or era despite the current scientific advances. Material and methodsA single center observational study included 38 participants from Moscow. The participants aged [&ge;] 40 years and given a written consent to participate in the study. Both groups, G1=19 with vs G2=19 without post stress induced myocardial perfusion defect, passed consultation by cardiologist, anthropometric measurements, blood pressure and pulse rate, echocardiography, cardio-ankle vascular index, performing bicycle ergometry, recording 3-minutes SCECG (using CARDO-QVARK ) before and just after bicycle ergometry, and then performing CTP. The LASSO regression with nested cross-validation was used to find association between CARDO-QVARK parameters and the existence of the perfusion defect. Statistical processing carried out using the R programming language v4.2 and Python v.3.10 [^R]. ResultsThe CARDO-QVARK parameters analysis have a specificity 63.2 % [95 % confidence interval (CI); 0.391 ; 0.833], sensitivity 73.7 % [95 % CI ; 0.533 ; 0.929], area under the curve (AUC) 68.4 % [95 % CI ; 0.527 ; 0.817] in compare to bicycle ergometry (AUC; 55.3 %), based on our study results. ConclusionThe SCECG have significantly higher diagnostic accuracy in compare to bicycle ergometry. CARDO-QVARK has the potential to improve the diagnostic accuracy of the bicycle ergometry. OtherFurther investigations required to uncover the hidden capabilities of CARDO-QVARK in the diagnosis of ischemic heart disease.

This review explores whether assessing myocardial viability before coronary revascularization meaningfully impacts outcomes in patients with ischemic cardiomyopathy. By synthesizing evidence from studies employing imaging techniques such as CMR, PET, SPECT, and dobutamine stress echocardiography, we examined associations between viability status and improvements in cardiac function and survival. Our findings suggest that patients with viable myocardium tend to derive greater benefit from revascularization, particularly in terms of left ventricular recovery and reduced mortality. These results highlight the potential value of viability imaging in guiding treatment decisions and support its selective use in clinical practice.

BackgroundVascular smooth muscle cells (VSMCs) plasticity is a central mechanism in cardiovascular health and disease. We aimed at providing deep cellular phenotyping, epigenomic and proteomic depiction of SMCs derived from induced pluripotent stem cells (iPSCs) and evaluating their potential as cellular models in the context of complex genetic arterial diseases. MethodsWe differentiated 3 human iPSC lines using either RepSox (R-SMCs) or PDGF-BB and TGF-{beta} (TP-SMCs), during the second half of a 24-days-long protocol. In addition to cellular assays, we performed RNA-Seq and assay for transposase accessible chromatin (ATAC)-Seq at 6 time-points of differentiation. The extracellular matrix content (matrisome) generated by iPSCs derived SMCs was analyzed using mass spectrometry. ResultsBoth iPSCs differentiation protocols generated SMCs with positive expression of SMC markers. TP-SMCs exhibited greater capacity of proliferation, migration and lower calcium release in response to contractile stimuli compared to R-SMCs. RNA-Seq data showed that genes involved in the contractile function of arteries were highly expressed in R-SMCs compared to TP-SMCs or primary SMCs. Matrisome analyses supported an overexpression of proteins involved in wound repair in TP-SMCs and a higher secretion of basal membrane constituents by R-SMCs. Open chromatin regions of R-SMCs and TP-SMCs were significantly enriched for variants associated with coronary artery disease and blood pressure, while only TP-SMCs were enriched for variants associated with peripheral artery disease. ConclusionsOur study portrayed two iPSCs derived SMCs models presenting complementary cellular phenotypes of high relevance to SMC plasticity. In combination with genome-editing tools, our data supports high relevance of the use of these cellular models to the study of complex regulatory mechanisms at genetic risk loci involved in several arterial diseases. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=179 HEIGHT=200 SRC="FIGDIR/small/490058v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@1f1002corg.highwire.dtl.DTLVardef@1426fa7org.highwire.dtl.DTLVardef@b05b56org.highwire.dtl.DTLVardef@3c6e88_HPS_FORMAT_FIGEXP M_FIG C_FIG

AimBrain Natriuretic Peptide (BNP) supplementation after infarction increases heart function and decreases heart remodeling. BNP receptors, NPR-A and NPR-B, are expressed on adult cardiomyocytes (CMs). We thus investigated whether a part of the BNP cardioprotective effect in infarcted and unmanipulated hearts is due to modulation of the CM fate. Methods and ResultsBNP was injected in infarcted adult mice and in unmanipulated neonatal and adult mice. CMs were isolated, counted and characterized. Increased number of CMs was detected in the hypoxic area of infarcted hearts, and in unmanipulated neonatal and adult hearts after BNP treatment. Accordingly, Troponin T plasma concentration was significantly reduced 1 and 3 days after infarction in BNP-treated mice, demonstrating less CM death. Furthermore, higher number of small, dedifferentiated and mononucleated CMs were identified in adult BNP-treated hearts when compared to saline-treated hearts. BNP-treated CMs express higher levels of mRNAs coding for hif1 alpha and for the different cyclins than CMs isolated from saline-treated hearts. Higher percentages of CMs undergoing DNA synthesis, expressing Ki67, phospho histone3 and Aurora B were detected in all BNP-treated hearts, which suggests that BNP stimulates CMs to re-enter to the cell cycle. Results in vitro confirmed that BNP stimulates the proliferation of the neonatal CMs and the dedifferentiation of the adult CMs. BNP effect on adult CMs in vivo is mediated by NPR-A binding and activation of the ERK MAP kinase pathway. Interestingly, increased number of CMs was also detected in adult infarcted hearts treated with LCZ696, which inhibits all natriuretic peptide degradations. ConclusionsAltogether, our results identified BNP and all therapies aimed to increase BNPs bioavailability (such as LCZ696 treatment) as new targets to increase heart regeneration. By protecting CMs from cell death, and by stimulating their proliferation, BNP treatment leads to increased number of CMs in neonatal, adult unmanipulated and infarcted hearts.

BackgroundIschemic postconditioning (PostC) serves as a vital defense for cardiomyocytes against the deleterious effects of ischemia/reperfusion (I/R) injury, the beneficial effects could be further enhanced through pharmacological strategies. Our prior research demonstrated upregulated expression of the GTP-binding protein RAP2C in H9C2 cells post hypoxia-reoxygenation (H/R). The cardioprotective effects of RAP2C and underlying mechanisms are unclear. We therefore explored the role of RAP2C in PostC-induced cardioprotection against I/R injury. MethodsOpen-chest rat I/R and primary cultured cardiomyocytes H/R models were used. RAP2C and MAP4K4 expression was detected by immunohistochemistry and Western blotting. The BioGRID and STRING databases were tapped to predict the RAP2C-MAP4K4 binding, which was confirmed by co-immunoprecipitation and immunofluorescence. ResultsResults indicated that I/R and H/R upregulated the protein levels of RAP2C, MAP4K4, phospho-JNK, phospho-P38, and phospho-ERK, concomitant with increased apoptosis. PostC mitigated these effects. The pro-apoptotic impacts and the activation of the MAPK pathway induced by H/R were attenuated by RAP2C knockdown and intensified by RAP2C overexpression. H/R increased the interaction between RAP2C and MAP4K4, and PostC attenuated this effect. MAP4K4 knockdown reduced the pro-apoptotic and MAPK-activating effects induced by both RAP2C overexpression and hypoxia/reoxygenation (H/R). ConclusionsThese results demonstrate that PostC reduces cardiomyocyte apoptosis via modulating RAP2C/MAP4K4 pathways, suggesting their potential as therapeutic targets for the treatment of ischemic heart disease.

BackgroundCardiac fibrosis is a component of all chronic heart diseases. JAZF1 regulates metabolism through various mechanisms; however, its role in cardiac fibrosis remains unclear. We aimed to investigate the role of JAZF1 in cardiac fibrosis. MethodsA rat cardiac fibrosis model was established by administering isoproterenol subcutaneously for 14 days (5 mg/kg/day); an equal volume of saline was administered to the control group. Cardiac fibroblasts (CFs) were treated with TGF-{beta}1 for 48 h to mimic cardiac fibrosis in vitro. ResultsJAZF1 expression at the protein and mRNA levels was enhanced in CFs and cardiac fibrosis tissues. JAZF1 downregulation suppressed CFs proliferation and migration. Western blotting showed that the PI3K/Akt signaling pathway was significantly decreased after JAZF1 knockdown. Further experiments revealed that SOX11 is an important transcription factor whose overexpression and downregulation enhanced and suppressed JAZF1 levels, respectively. Luciferase analysis showed that SOX11 interacted with the JAZF1 promoter. Moreover, SOX11 promoted cardiac fibrosis by regulating JAZF1 expression. ConclusionsJAZF1 was enhanced in cardiac fibrosis tissue and TGF-{beta}-treated CFs. JAZF1 knockdown decreased CFs migration and proliferation, possibly remediated by SOX11 with activation of PI3k/Akt signaling pathways.

BACKGROUNDAssociations between cancer and cardiovascular disease (CVD) have been reported previously in observational studies. However, the causal relationship between the specific subspecies of the two diseases remains unclear. This study used a two-sample bidirectional MR study to investigate the causal relationship between different types of CVDs and the major types of malignancies and vice-versa. METHODS AND RESULTSWe extracted summary statistics for coronary atherosclerosis, hypertension, hypertrophic cardiomyopathy, heart failure, atrial fibrillation, stroke, and 14 common malignancies from published relevant genome-wide association studies as instrumental variables. We conducted two-sample bidirectional Mendelian randomization (MR) studies to assess the causal relationship between CVD and cancer in which the inverse variance weighting (IVW) method was the main method. Multiple comparison calibration, sensitivity analysis, and heterogeneity analysis were performed to improve the reliability and robustness of the results. The evidence from IVW analyses showed that genetically predicted coronary atherosclerosis was suggestively associated with a decreased risk of endometrial cancer (OR=0.053, 95% CI: 0.004-0.648, P=0.022); hypertension was suggestively associated with an increased risk of oral cavity/pharyngeal cancer (OR=14.872, 95% CI: 1.324-167.053, P=0.029); hypertrophic cardiomyopathy was suggestively associated with a decreased risk of brain cancer (OR=0.479, 95% CI: 0.257-0.890, P=0.020); any stroke was suggestively associated with a decreased risk of breast cancer (OR=0.798, 95% CI: 0.669-0.952, P=0.012) and prostate cancer (OR=0.844, 95% CI: 0.737-0.966, P=0.014) since their significance weakened after multiple testing. In the reverse MR analysis, bladder cancer was associated with an increased risk of coronary atherosclerosis (OR=1.426, 95% CI: 1.051-1.934, P= 0.023) and hypertension (OR=1.689, 95% CI: 1.115-2.557, P=0.013); pancreatic cancer was associated with an increased risk of any stroke (OR= 1.047, 95% CI: 1.005-1.090, P= 0.027), losing significance after multivariate testing. Prostate cancer was significantly associated with an increased risk of heart failure (OR= 1.030, 95% CI: 1.009-1.053, P= 0.006); cervical cancer was significantly associated with an increased risk of any stroke (OR= 8.751686e+03, 95% CI: 35.043-2.185650e+06, P= 0.001). CONCLUSIONSCausal relationships for specific types of CVD and cancer were found in this MR Study, although some were suggestive. This study provides ideas for the follow-up management of these two common chronic diseases. CLINICAL PERSPECTIVEO_ST_ABSWhat Is New?C_ST_ABSO_LISome observational studies have shown that cardiovascular diseases (CVDs) and cancer have complex causal relationships dominated by positive associations. However, the role of genetic factors in their comorbidities remains unclear. C_LIO_LIIn this study, by utilizing data from genome-wide association studies, we identified a significant genetic correlation between multiple groups of specific classes of CVDs and specific types of malignancy, along with the shared risk snp. Some of the results are contrary to previous reports and warrant further research. These findings could provide insights into the shared genetic architecture between CVD and cancer. C_LI What Are the Clinical Implications?This study adds to the understanding of the underlying causal relationships of different phenotypes of CVD and cancer, with implications for the prediction and prevention of these common comorbidities.

RationaleCardiac neural crest cells (CNCCs) contribute greatly to cardiovascular development. A thorough understanding of the cell lineages, transcriptomic states and regulatory networks of CNCC derivatives during normal development is essential for deciphering the pathogenesis of CNCC-associated congenital anomalies. However, the transcriptomic landscape of CNCC derivatives during development has not yet been examined at a single-cell resolution.\n\nObjectiveWe sought to systematically characterize the cell lineages, define the developmental chronology and elucidate the transcriptomic dynamics of CNCC derivatives during embryonic and neonatal development.\n\nMethods and ResultsWe performed single-cell transcriptomic sequencing of 34,131 CNCC-derived cells in mouse hearts from eight developmental stages between E10.5 and P7. Through single-cell analyses and single-molecule fluorescence in situ hybridization, we confirmed the presence of CNCC-derived mural cells. Furthermore, we found the transition from CNCC-derived pericytes to microvascular smooth muscle cells, and identified the genes that were significantly regulated during this transition through pseudo-temporal analysis. CNCC-derived neurons first appeared at E10.5, which was earlier than previously recognized. In addition, the CNCC derivatives switched from a proliferative to a quiescent state with the progression of development. Gradual loss of the neural crest molecular signature with development was also observed in the CNCC derivatives. Our data suggested that many CNCC-derivatives had already committed or differentiated to a specific lineage when migrating to the heart. Finally, we characterized some previously unknown subpopulations of CNCC derivatives during development. For example, we found that Penk+ cells, which were mainly localized in outflow tract cushions, were all derived from CNCCs.\n\nConclusionsOur study provides novel insights into the cell lineages, molecular signatures, developmental chronology and state change dynamics of CNCC derivatives during embryonic and neonatal development. Our dataset constitutes a valuable resource that will facilitate future efforts in exploring the role of CNCC derivatives in development and disease.

BackgroundNeutrophils are the most rapid and abundant immune cells to infiltrate the myocardium following myocardial ischemia/reperfusion injury (MI/R). Neutrophil heterogeneity has not been well characterized in MI/R, and studies have shown conflicting results regarding the impact of neutrophil depletion on cardiac injury. We thus aim to study the impact of neutrophils with enriched type I interferon signature and the role of STING (stimulator of interferon genes) signaling in neutrophils on cardiac reperfusion injury. MethodsWe utilized single-cell RNA sequencing to study neutrophil heterogeneity in response to MI/R. We generated a neutrophil-specific STING knockout mouse to assess the role of neutrophil STING in a model of MI/R. We examined cardiac function following injury via echocardiography and assessed the immune cell trajectory following injury utilizing flow cytometry. ResultsWe identified a population of neutrophils with enriched type I interferon signaling and response to type I interferon following MI/R. We found that genetic deletion of neutrophil-specific STING led to worsened cardiac function following MI/R. Further investigation of the immune response by flow cytometry revealed decreased neutrophil infiltration into the myocardium and a shift in macrophage polarization. ConclusionsOur findings suggest that neutrophil-specific STING is cardioprotective in MI/R, partly due to its effects on downstream immune cells. These results demonstrate that early alterations or therapeutic interventions can influence key events in the resolution of inflammation following MI/R.

BackgroundWhile cardiomyocytes undergo terminal differentiation postnatally and rarely re-enter the cell cycle, the endogenous mechanisms that propagate differentiation and prevent de-differentiation remain unclear. The monomeric heme protein myoglobin, which stores oxygen and regulates reactive oxygen/nitrogen species balance in the heart, increases in expression by over 50% during cardiomyocyte differentiation. Though myoglobin deletion without significant compensation is embryonic lethal in mice, a role for the protein in regulating cardiomyocyte differentiation has not been tested. We hypothesized that myoglobin expression is required for cardiomyocyte differentiation and the loss of myoglobin enables de-differentiation. MethodsMyoglobin was genetically silenced in HL-1, H9C2 cells, and neonatal rat ventricular cardiomyocytes (NRVM) to examine myoglobin-dependent effects on differentiation, proliferation, and Hippo pathway signaling. A zebrafish model of Mb depletion was made using CRISPR-Cas9 to test the effect of myoglobin depletion on cardiac regeneration after apical resection injury in vivo. ResultsMyoglobin deletion in cultured cell lines and NRVM decreased the gene expression of cardiomyocyte differentiation markers (troponin, myosin light chain, and myosin heavy chain), upregulated markers of dedifferentiation (runx1 and dab2) and stimulated cell proliferation. Mechanistically, we show that the heme prosthetic group of myoglobin catalyzes the oxidation of the Hippo pathway kinase LATS1, which activates the enzyme to phosphorylate the downstream Yes-associated protein (YAP) transcription factor, which prevents its transcriptional activity. Thus, the loss of myoglobin results in the de-phosphorylation and nuclear translocation of YAP, which propagates proliferation and fetal gene expression. In vivo, myoglobin-deficient zebrafish hearts recapitulated the increase in YAP signaling and showed accelerated regeneration at 20 days post apical injury. ConclusionWe a novel role for myoglobin as an endogenous driver of cardiomyocyte differentiation, and a regulator of the Hippo pathway. These findings suggest myoglobin as a potential target for strategies to enhance cardiac development and improve cardiac repair and regeneration.