Hypertrophied Hearts Research Articles

Abstract MP252: Genetic Architecture Of Heart Mitochondrial Proteome Influencing Cardiac Hypertrophy

Our lab studies how natural genetic variations affect common diseases using a mouse population called hybrid mouse diversity panel (HMDP). In this study, we have explored the genetic regulation of mitochondrial pathways and their contribution to heart function using an integrative proteomics approach. We first performed a whole heart proteomic analysis in the HMDP (72 strains, n=2-3 mice) and surveyed mitochondrial localization using MitoCarta2.0. We retrieved 840 of these proteins (quantified in ≥50 strains) and performed high-resolution association mapping on their respective abundance levels to the HMDP genotypes. Our analyses identified three genetic loci, located on chromosome (chr) 7, chr13 and chr17, that control distinct classes of mitochondrial proteins as well as heart hypertrophy. Follow-up high resolution regional mapping identified NDUFS4, LRPPRC and COQ7 as the candidate genes for chr13, chr17 and chr7 loci, respectively. All three are associated with heart mass in two independent heart stress models, namely, isoproterenol (ISO)-induced heart failure and diet-induced obesity (DIO) models. Next, to identify the aspects of mitochondrial metabolism regulated by these loci, we constructed co-expression protein networks using weighted gene co-expression network analysis (WGCNA) and identified five modules. Eigengenes, representing the first principal component of two of these modules (Brown and Green), mapped to the same regions as the chr13 and chr17 loci, respectively. DAVID enrichment analyses revealed that the Brown module (72 proteins, 96% overlap with chr13) was highly enriched for complex-I proteins (35 proteins, P = 8.8E-74) and the Green module (44 proteins, 73% overlap with chr17) for mitochondrial ribosomal proteins (25 proteins, P = 1.3E-53). The proteins in the chr7 locus were found primarily in the Turquoise module (393 proteins, 81% overlap) but this module was not enriched for any single mitochondrial protein complex. In summary, we now report the identification of three genetic loci that control distinct classes of mitochondrial proteins as well as heart hypertrophy. Our results provide strong support for a role of the mitochondrial proteome in heart pathophysiology.

Abstract P407: Role Of Cyclic AMP During The Intracellular Infection Cycle Of Trypanosoma Cruzi

Trypanosoma cruzi is the causative agent of Chagas disease, a vector-borne disease. In the 1990s the distribution of the vector, a hematophagous triatomine, and consequently the parasite, was from the southeast tropical regions of Mexico to South America. Now, global warming is causing this distribution to expand to northern territories in Mexico, reaching southern parts of US, in which up to 300,000 people are affected. Furthermore, an increase in chronically-infected immigrants to the US makes Chagas disease a matter of Pan-American public health that it should be addressed by all the America countries. Chagas disease manifests clinically as cardiovascular disease, characterized by hypertrophy of heart, esophagus and colon. Congestive heart failure is the main cause of death (58%) in Chagas patients, whereas cardiac arrhythmias and unexpected deaths add another 36%. A major cause of heart pathology in Chagas disease damage is caused by the host immune system, as it attacks chronically infected tissue. Therefore, pathology of the disease is a direct consequence of the ability of the parasite to invade host cells, so it can establish chronic infection. To achieve this, T. cruzi must sense and adapt to the host environment, but the underlying mechanisms are poorly understood. In particular, parasite signaling pathways used to sense and transduce signals from the host environment are most completely unknown. Our lab studies cAMP signaling in trypanosome parasites and several lines of evidence suggest T. cruzi cAMP signaling is important for host cell invasion, differentiation and persistent infection, which in turn underlies heart tissue pathology of Chagas disease. A transcriptome analysis revealed that mRNA of proteins involved in cAMP metabolism, i.e. adenylate cyclases and phosphodiesterases, are either upregulated or downregulated during the intracellular infection cycle. In fact, the phosphodiesterases have flagellar homologs with known cAMP signaling functions in a related parasite. This suggests that cAMP might fluctuate during as T. cruzi invades, differentiates, and multiplies inside the host cells. We have implemented a cAMP FRET sensor to monitor cAMP levels in trypanosomes to understand the role of cAMP in T. cruzi pathogenesis.

Abstract MP217: Nuclease-deficient Cas9 Transcription Factors Restore Krueppel-like Factor 15 Expression In Stressed Mouse And Human Cardiomyocytes

Transcriptional changes in cardiomyocytes drive heart failure progression, however, precise control over endogenous gene expression remains challenging. The expression of Krueppel-like factor 15 ( KLF15 ), an evolutionary conserved nuclear and cardiomyocyte specific inhibitor of WNT/CTNNB1 signalling in the heart, is lost upon cardiac remodelling, and accompanied by aberrantly active WNT/CTNNB1 resulting in heart failure progression. We investigated KLF15 expression dynamics employing CRISPR/Cas9-based tools in mouse cardiomyocytes in vivo and in human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM) under the hypothesis that re-establishment of KLF15 levels in myocardial stress conditions prevents heart failure progression. Using a mouse model expressing enzymatically inactive Cas9 (dCas9) fused to transcriptional activators (VPR) under Myh6 -promoter control, we activated Klf15 in a murine pressure overload model by transverse aortic constriction. Delivery of Klf15 gRNAs targeted to the Klf15 promoter region via AAV9 induced Klf15 expression sufficiently to re-normalize Klf15 expression to transcript levels comparable to sham surgery hearts. This was accompanied by reduced decrease of fractional shortening as well as reduced cardiomyocyte hypertrophy in stressed Klf15 re-activated hearts compared to non-trageted (NT) gRNA hearts (n=3-8 per group, echo data from 4 and 8 weeks post-surgery). We achieved titratable KLF15 activation in dCas9VPR transgenic hiPSC-CM by selection of single and multiple gRNAs (n=3-4 replicates) and used these cells to generate human engineered myocardium by combining hiPSC-CM and fibroblasts which we subjected to isometric contractions in order to induce mechanical stress, which resulted in KLF15 expressional decrease in line with our in vivo data. This transcriptional loss was rescued in CRISPR/dCas9VPR hiPSC-CM targeted to the KLF15 locus compared to controls (n=6-9/2/4 tissues per group/casting sessions/differentiations). Additionally, TGFB1 induced cardiomyocyte stress resulted in decreased KLF15 expression levels in 2D hiPSC-CM cultures which were rescued by dCas9VPR- KLF15 targeting (n=3 experiments). In conclusion, we report controllable gene activity by CRISPR/dCas9VPR to restore the loss of KLF15 in stressed mouse and human cardiomyocytes. We furthermore evaluate the potential to gain full control over gene dose titratability with these models to validate and define novel therapeutic targets for the prevention of heart failure progression.

TANK Promotes Pressure Overload Induced Cardiac Hypertrophy via Activating AKT Signaling Pathway.

Background: TANK (TRAF family member associated NF-κB activator) acts as a member of scaffold proteins participated in the development of multiple diseases. However, its function in process of cardiac hypertrophy is still unknown.Methods and Results: In this study, we observed an increased expression of TANK in murine hypertrophic hearts after aortic banding, suggesting that TANK may be involved in the pathogenesis of cardiac hypertrophy. We generated cardiac-specific TANK knockout mice, and subsequently subjected to aortic banding for 4–8 weeks. TANK knockout mice showed attenuated cardiac hypertrophy and dysfunction compared to the control group. In contrast, cardiac-specific TANK transgenic mice showed opposite signs. Consistently, in vitro experiments revealed that TANK knockdown decreased the cell size and expression of hypertrophic markers. Mechanistically, AKT signaling was inhibited in TANK knockout mice, but activated in TANK transgenic mice after aortic banding. Blocking AKT signaling with a pharmacological AKT inhibitor alleviated the cardiac hypertrophy and dysfunction in TANK transgenic mice.Conclusions: Collectively, we identified TANK accelerates the progression of pathological cardiac hypertrophy and is a potential therapeutic target.

Congestive heart failures caused by myxomatous mitral valve degeneration in a Siberian tiger

A 19-year-old male Siberian tiger was presented with inappetence and paralysis of hind limbs. In a computed tomography (CT) scan, intervertebral disk disease at L3–L4 was detected. Cardiac arrest occurred during the surgery. At autopsy, myxomatous mitral valve degeneration (MMVD) and eccentric hypertrophy of the left heart were noted. The diagnosis was congestive heart failure caused by MMVD. Microscopically, myocardial and pulmonary fibrosis were observed in addition to the disintegration of the fibrosa layer and accumulation of glycosaminoglycans and proteoglycans in the spongiosa layer of the mitral valve. This is the first case of congestive heart failure with MMVD in a Siberian tiger.

Abstract P140: Mutant Mice Carrying Global Loss Of Npr1 Exhibit Cardiac Fibrosis, Hypertrophy, And Congestive Heart Failure: Implication Of TGF-Beta/SMAD Signaling Pathway

The cardiac hormones, atrial and brain natriuretic peptides (ANP and BNP) bind to natriuretic peptide receptor-A (NPRA), which synthesizes the second messenger cGMP. The objective of this study was to determine the underlying mechanisms that regulate the development of cardiac hypertrophy, fibrosis, and congestive heart failure (CHF) in Npr1 (encoding NPRA) gene-knockout mice. The Npr1 null mutant ( Npr1 -/- , 0-copy), heterozygous ( Npr1 +/- , 1-copy), and wild-type ( Npr1 +/+ , 2-copy) mice were orally administered with transforming growth factor-β1 receptor I (TGF-β1R1) antagonist, GW788388 (2 mg/kg/day) by oral gavage for 28 days. The left ventricular end-diastolic dimension (LVEDD), left ventricular end-systolic dimension (LVEDS), posterior wall thickness (PWT), and percent fractional shortening (FS) were analyzed by echocardiography. The heart was isolated and used for the analysis of fibrotic markers using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and Western blot methods. The heart weight-to-body weight (HW/BW) ratio, LVEDD, LVEDS and PWT were significantly (p<0.005) increased in Npr1 -/- and Npr1 +/- mice than wild-type Npr1 +/+ mice. The FS was greatly reduced in Npr1 -/- and Npr1 +/- mice compared with Npr1 +/+ mice. The Npr1 -/- null mutant (0-copy) mice showed 52% increase in HW/BW ratio and 6-fold induction of cardiac fibrosis as compared with 2-copy control mice. The cardiac expression of fibrotic markers including collagen-1a (COL-1a; 3.5-fold), connective tissue growth factor (CTGF; 5-fold), α-smooth muscle actin (α-SMA; 4-fold), TGF-β1RI (4-fold), TGF-β1RII (3.5-fold), and SMAD-2/3 proteins (3-to-5 fold) were significantly increased in Npr1 -/- and Npr1 +/- mutant mice compared with age-matched Npr1 +/+ animals. The treatment with TGF-β1R1 antagonist, significantly (p<0.001) prevented the cardiac hypertrophy, fibrosis, CHF, and down-regulated the expression of fibrotic markers and SMAD proteins in mutant mice. The LVEDD, LVEDS, and FS were significantly (p<0.001) improved in the drug treated Npr1 -/- mice. The present results indicate that the cardiac hypertrophy, fibrosis, and CHF in Npr1 mutant mice is regulated through the TGF-β1-mediated SMAD-dependent signaling pathway.

Cardiac macrophage subsets differentially regulate lymphatic network remodeling during pressure overload

The lymphatic network of mammalian heart is an important regulator of interstitial fluid compartment and immune cell trafficking. We observed a remodeling of the cardiac lymphatic vessels and a reduced lymphatic efficiency during heart hypertrophy and failure induced by transverse aortic constriction. The lymphatic endothelial cell number of the failing hearts was positively correlated with cardiac function and with a subset of cardiac macrophages. This macrophage population distinguished by LYVE-1 (Lymphatic vessel endothelial hyaluronic acid receptor-1) and by resident macrophage gene expression signature, appeared not replenished by CCR2 mediated monocyte infiltration during pressure overload. Isolation of macrophage subpopulations showed that the LYVE-1 positive subset sustained in vitro and in vivo lymphangiogenesis through the expression of pro-lymphangiogenic factors. In contrast, the LYVE-1 negative macrophage subset strongly expressed MMP12 and decreased the endothelial LYVE-1 receptors in lymphatic endothelial cells, a feature of cardiac lymphatic remodeling in failing hearts. The treatment of mice with a CCR2 antagonist during pressure overload modified the proportion of macrophage subsets within the pathological heart and preserved lymphatic network from remodeling. This study reports unknown and differential functions of macrophage subpopulations in the regulation of cardiac lymphatic during pathological hypertrophy and may constitute a key mechanism underlying the progression of heart failure.

Cardiomyocyte peroxisome proliferator-activated receptor α is essential for energy metabolism and extracellular matrix homeostasis during pressure overload-induced cardiac remodeling.

Peroxisome proliferator-activated receptor α (PPARα), a ligand-activated nuclear receptor critical for systemic lipid homeostasis, has been shown closely related to cardiac remodeling. However, the roles of cardiomyocyte PPARα in pressure overload-induced cardiac remodeling remains unclear because of lacking a cardiomyocyte-specific Ppara-deficient (PparaΔCM) mouse model. This study aimed to determine the specific role of cardiomyocyte PPARα in transverse aortic constriction (TAC)-induced cardiac remodeling using an inducible PparaΔCM mouse model. PparaΔCM and Pparafl/fl mice were randomly subjected to sham or TAC for 2 weeks. Cardiomyocyte PPARα deficiency accelerated TAC-induced cardiac hypertrophy and fibrosis. Transcriptome analysis showed that genes related to fatty acid metabolism were dramatically downregulated, but genes critical for glycolysis were markedly upregulated in PparaΔCM hearts. Moreover, the hypertrophy-related genes, including genes involved in extracellular matrix (ECM) remodeling, cell adhesion, and cell migration, were upregulated in hypertrophic PparaΔCM hearts. Western blot analyses demonstrated an increased HIF1α protein level in hypertrophic PparaΔCM hearts. PET/CT analyses showed an enhanced glucose uptake in hypertrophic PparaΔCM hearts. Bioenergetic analyses further revealed that both basal and maximal oxygen consumption rates and ATP production were significantly increased in hypertrophic Pparafl/fl hearts; however, these increases were markedly blunted in PparaΔCM hearts. In contrast, hypertrophic PparaΔCM hearts exhibited enhanced extracellular acidification rate (ECAR) capacity, as reflected by increased basal ECAR and glycolysis but decreased glycolytic reserve. These results suggest that cardiomyocyte PPARα is crucial for the homeostasis of both energy metabolism and ECM during TAC-induced cardiac remodeling, thus providing new insights into potential therapeutics of cardiac remodeling-related diseases.

Deep learning analysis of resting electrocardiograms for the detection of myocardial dysfunction, hypertrophy, and ischaemia: a systematic review.

The aim of this review was to assess the evidence for deep learning (DL) analysis of resting electrocardiograms (ECGs) to predict structural cardiac pathologies such as left ventricular (LV) systolic dysfunction, myocardial hypertrophy, and ischaemic heart disease. A systematic literature search was conducted to identify published original articles on end-to-end DL analysis of resting ECG signals for the detection of structural cardiac pathologies. Studies were excluded if the ECG was acquired by ambulatory, stress, intracardiac, or implantable devices, and if the pathology of interest was arrhythmic in nature. After duplicate reviewers screened search results, 12 articles met the inclusion criteria and were included. Three articles used DL to detect LV systolic dysfunction, achieving an area under the curve (AUC) of 0.89–0.93 and an accuracy of 98%. One study used DL to detect LV hypertrophy, achieving an AUC of 0.87 and an accuracy of 87%. Six articles used DL to detect acute myocardial infarction, achieving an AUC of 0.88–1.00 and an accuracy of 83–99.9%. Two articles used DL to detect stable ischaemic heart disease, achieving an accuracy of 95–99.9%. Deep learning models, particularly those that used convolutional neural networks, outperformed rules-based models and other machine learning models. Deep learning is a promising technique to analyse resting ECG signals for the detection of structural cardiac pathologies, which has clinical applicability for more effective screening of asymptomatic populations and expedited diagnostic work-up of symptomatic patients at risk for cardiovascular disease.

Key Roles of RGD-Recognizing Integrins During Cardiac Development, on Cardiac Cells, and After Myocardial Infarction

Cardiac cells interact with the extracellular matrix (ECM) proteins through integrin mechanoreceptors that control many cellular events such as cell survival, apoptosis, differentiation, migration, and proliferation. Integrins play a crucial role in cardiac development as well as in cardiac fibrosis and hypertrophy. Integrins recognize oligopeptides present on ECM proteins and are involved in three main types of interaction, namely with collagen, laminin, and the oligopeptide RGD (Arg-Gly-Asp) present on vitronectin and fibronectin proteins. To date, the specific role of integrins recognizing the RGD has not been addressed. In this review, we examine their role during cardiac development, their role on cardiac cells, and their upregulation during pathological processes such as heart fibrosis and hypertrophy. We also examine their role in regenerative and angiogenic processes after myocardial infarction (MI) in the peri-infarct area. Specific targeting of these integrins may be a way of controlling some of these pathological events and thereby improving medical outcomes.

ELAC2/RNaseZ-linked cardiac hypertrophy in Drosophila melanogaster.

ABSTRACTA severe form of infantile cardiomyopathy (CM) has been linked to mutations in ELAC2, a highly conserved human gene. It encodes Zinc phosphodiesterase ELAC protein 2 (ELAC2), which plays an essential role in the production of mature tRNAs. To establish a causal connection between ELAC2 variants and CM, here we used the Drosophila melanogaster model organism, which carries the ELAC2 homolog RNaseZ. Even though RNaseZ and ELAC2 have diverged in some of their biological functions, our study demonstrates the use of the fly model to study the mechanism of ELAC2-related pathology. We established transgenic lines harboring RNaseZ with CM-linked mutations in the background of endogenous RNaseZ knockout. Importantly, we found that the phenotype of these flies is consistent with the pathological features in human patients. Specifically, expression of CM-linked variants in flies caused heart hypertrophy and led to reduction in cardiac contractility associated with a rare form of CM. This study provides first experimental evidence for the pathogenicity of CM-causing mutations in the ELAC2 protein, and the foundation to improve our understanding and diagnosis of this rare infantile disease. This article has an associated First Person interview with the first author of the paper.

De-ubiquitination of p300 by USP12 Critically Enhances METTL3 Expression and Ang II-induced cardiac hypertrophy

Stresses, such as neurohumoral activation, induced pathological cardiac hypertrophy is the main risk factor for heart failure. The ubiquitin-proteasome system (UPS) plays a key role in maintaining protein homeostasis and cardiac function. However, research on the role and mechanism of deubiquitinating enzymes (DUBs) in cardiac hypertrophy is limited. Here, we observe that the deubiquitinating enzyme ubiquitin-specific protease 12(USP12) is upregulated in Ang II-induced hypertrophic hearts and primary neonatal rat cardiomyocytes (NRCMs). Inhibition of USP12 ameliorate Ang II-induced myocardial hypertrophy, while overexpression of USP12 have the opposite effect. USP12 deficiency also significantly attenuate the phenotype of Ang II-induced cardiac hypertrophy in vivo. Moreover, we demonstrate that USP12 aggravate Ang II-induced cardiac hypertrophy by enhancing METTL3, a methyltransferase which catalyze N6-methyladenosine (m6A) modification on messenger RNA and acts as a harmful factor in pathological cardiac hypertrophy. Upregulation of METTL3 reverse the reduction of myocardial hypertrophy induced by USP12 silencing in NRCMs. In contrast, knockdown of METTL3 attenuate the aggravation of myocardial hypertrophy in USP12-overexpressing NRCMs. Furthermore, we discover that USP12 promote the expression of METTL3 via upregulating p300. Mechanistically, USP12 binds and stabilizes p300, thereby activating the transcription of its downstream gene METTL3. Finally, our data show that USP12 is partially dependent on the stabilization of p300 to activate METTL3 expression and promote myocardial hypertrophy. Taken together, our results demonstrate that USP12 acts as a pro-hypertrophic deubiquitinating enzyme via enhancing p300/METTL3 axis, indicating that targeting USP12 could be a potential treatment strategy for pathological cardiac hypertrophy.

Changes in miR 21 and 23b expression in postnatal hypertrophic heart derived from gestational diabetes precede dilated cardiomyopathy

Gestational diabetes mellitus (GDM) increases the risk of fetal congenital ventricular hypertrophic cardiomyopathy (HCM). We explored the effects and mechanisms of the postnatal progression of fetal hypertrophic failure in rat pups with STZ-induced Gestational Diabetes (GD). The hearts of rat pups (newborn [NB], 8, 15, 25 and 35 days postnatal) were obtained. Histological characteristics and expression of collagen were evaluated. In-gel-gelatin zymography for MMP-9 activation was performed. Adrenergic receptors (α2AR and β3AR), myosins (Myc6 and Myc7), Bcl-2 and Bax mRNA expression were quantified by qRT-PCR. Fetal hypertrophy of the left ventricular lateral wall (LVLW) in rat pups with DG persists until day 8, although this process appears to be reversed during the postnatal stage. The temporal continuity of the study demonstrated a thinning of the ventricular wall, similar to dilated cardiomyopathy (DCM). This ventricular remodeling process is associated with the expression of β3 adrenergic receptors and miR-21, -23b. The Bax/Bcl2 ratio was significantly reduced only at early ages. In addition, the increase in interstitial space in all ages, as well as the predominance of early ages expression of Col2 and increased expression of Col3, MMP-9 and Cx43 in late ages, is the result of an active extracellular remodeling in the hearts of rat pups with GD.

Skeletal Muscle Microvascular Dysfunction Manifests Early in Diabetic Cardiomyopathy.

Aim: To perform a deep cardiac phenotyping of type II diabetes in a rat model, with the goal of gaining new insight into the temporality of microvascular dysfunction, cardiac dysfunction, and exercise intolerance at different stages of diabetes.Methods and Results: Diabetes was reproduced using a non-obese, diet-based, low-dose streptozotocin model in male rats (29 diabetic, 11 control). Time-course monitoring over 10 months was performed using echocardiography, treadmill exercise, photoacoustic perfusion imaging in myocardial and leg skeletal muscle, flow-mediated dilation, blood panel, and histology. Diabetic rats maintained a normal weight throughout. At early times (4 months), a non-significant reduction (30%) emerged in skeletal muscle perfusion and in exercise tolerance. At the same time, diabetic rats had a normal, slightly lower ejection fraction (63 vs. 71% control, p < 0.01), grade 1 diastolic dysfunction (E/A = 1.1 vs. 1.5, isovolumetric relaxation time = 34 vs. 27 ms; p < 0.01), mild systolic dysfunction (ejection time = 69 vs. 57 ms, isovolumetric contraction time = 21 vs. 17 ms; p < 0.01), and slightly enlarged left ventricle (8.3 vs. 7.6 mm diastole; p < 0.01). Diastolic dysfunction entered grade 3 at Month 8 (E/A = 1.7 vs. 1.3, p < 0.05). Exercise tolerance remained low in diabetic rats, with running distance declining by 60%; in contrast, control rats ran 60% farther by Month 5 (p < 0.05) and always remained above baseline. Leg muscle perfusion remained low in diabetic rats, becoming significantly lower than control by Month 10 (33% SO2 vs. 57% SO2, p < 0.01). Myocardial perfusion remained normal throughout. Femoral arterial reactivity was normal, but baseline velocity was 25% lower than control (p < 0.05). High blood pressure appeared late in diabetes (8 months). Histology confirmed absence of interstitial fibrosis, cardiomyocyte hypertrophy, or microvascular rarefaction in the diabetic heart. Rarefaction was also absent in leg skeletal muscle.Conclusion: Reduced skeletal muscle perfusion from microvascular dysfunction emerged early in diabetic rats, but myocardial perfusion remained normal throughout the study. At the same time, diabetic rats exhibited exercise intolerance and early cardiac dysfunction, in which changes related to heart failure with preserved ejection fraction (HFpEF) were seen. Importantly, skeletal muscle microvascular constrictionadvanced significantly before the late appearance of hypertension. HFpEF phenotypes such as cardiac hypertrophy, fibrosis, and rarefaction, which are typically associated with hypertension, were absent over the 10 month time-course of diabetes-related heart failure.

Stable Gastric Pentadecapeptide BPC 157 Therapy for Monocrotaline-Induced Pulmonary Hypertension in Rats Leads to Prevention and Reversal.

Background. Monocrotaline selectively injures the lung’s vascular endothelium and induces pulmonary arterial hypertension. The stable gastric pentadecapeptide BPC 157 acts as a prototype cytoprotective agent that maintains endothelium, and its application may be a novel therapy. Besides, BPC 157 prevents and reverses thrombosis formation, maintains platelet function, alleviates peripheral vascular occlusion disturbances, and has anti-arrhythmic and anti-inflammatory effects. Monocrotaline-induced pulmonary arterial hypertension in rats (wall thickness, total vessel area, heart frequency, QRS axis deviation, QT interval prolongation, increase in right ventricle systolic pressure and bodyweight loss) can be counteracted with early or delayed BPC 157 therapy. Methods and Results. After monocrotaline (80 mg/kg subcutaneously), BPC 157 (10 μg/kg or 10 ng/kg, days 1–14 or days 1–30 (early regimens), or days 14–30 (delayed regimen)) was given once daily intraperitoneally (last application 24 h before sacrifice) or continuously in drinking water until sacrifice (day 14 or 30). Without therapy, the outcome was the full monocrotaline syndrome, marked by right-side heart hypertrophy and massive thickening of the precapillary artery’s smooth muscle layer, clinical deterioration, and sometimes death due to pulmonary hypertension and right-heart failure during the 4th week after monocrotaline injection. With all BPC 157 regimens, monocrotaline-induced pulmonary arterial hypertension (including all disturbed parameters) was counteracted, and consistent beneficial effects were documented during the whole course of the disease. Pulmonary hypertension was not even developed (early regimens) as quickly as the advanced pulmonary hypertension was rapidly attenuated and then completely eliminated (delayed regimen). Conclusions. Thus, pentadecapeptide BPC 157 prevents and counteracts monocrotaline-induced pulmonary arterial hypertension and cor pulmonale in rats.

Anderson-fabry disease: role of traditional and new cardiac MRI techniques.

Anderson-Fabry (FD) disease is a rare X-linked disorder caused by different mutations in the Galactosidase α (GLA) gene, which leads to α-galactosidase A enzyme deficiency and the storage of glycosphingolipids in different kinds of organs, included the heart. This results in myocardial inflammation and left ventricular hypertrophy (LVH) and fibrosis. Echocardiography and cardiac magnetic resonance (C-MRI), in particular with new techniques, such as mapping analysis, late gadolinium enhancement (LGE) assessment and strain imaging, are important tools that allow a correct diagnosis, discriminating FD from other hypertrophic heart conditions. C-MRI is able to detect tissue alterations in the early stages of the disease, when an appropriate treatment could be more effective, and it has a fundamental role in monitoring therapy.

Targeting mitochondrial reactive oxygen species-mediated oxidative stress attenuates nicotine-induced cardiac remodeling and dysfunction

Long-term nicotine intake is associated with an increased risk of myocardial damage and dysfunction. However, it remains unclear whether targeting mitochondrial reactive oxygen species (ROS) prevents nicotine-induced cardiac remodeling and dysfunction. This study investigated the effects of mitoTEMPO (a mitochondria-targeted antioxidant), and resveratrol (a sirtuin activator) , on nicotine-induced cardiac remodeling and dysfunction. Sprague–Dawley rats were administered 0.6 mg/kg nicotine daily with 0.7 mg/kg mitoTEMPO, 8 mg/kg resveratrol, or vehicle alone for 28 days. At the end of the study, rat hearts were collected to analyze the cardiac structure, mitochondrial ROS level, oxidative stress, and inflammation markers. A subset of rat hearts was perfused ex vivo to determine the cardiac function and myocardial susceptibility to ischemia–reperfusion injury. Nicotine administration significantly augmented mitochondrial ROS level, cardiomyocyte hypertrophy, fibrosis, and inflammation in rat hearts. Nicotine administration also induced left ventricular dysfunction, which was worsened by ischemia–reperfusion in isolated rat hearts. MitoTEMPO and resveratrol both significantly attenuated the adverse cardiac remodeling induced by nicotine, as well as the aggravation of postischemic ventricular dysfunction. Findings from this study show that targeting mitochondrial ROS with mitoTEMPO or resveratrol partially attenuates nicotine-induced cardiac remodeling and dysfunction.

Resveratrol Confers Protection Against Ischemia/Reperfusion Injury by Increase of Angiotensin (1-7) Expression in a Rat Model of Myocardial Hypertrophy.

Left ventricular hypertrophy (LVH) makes the heart vulnerable to ischemia/reperfusion (IR) injury. Angiotensin (Ang) (1-7) is recognized as a cardioprotective peptide. We investigated the effect of polyphenol resveratrol on myocardial IR injury after hypertrophy and examined cardiac content of Ang (1-7) and transcription of its receptor (MasR). Rats were divided into sham-operated, LVH, IR, LVH + IR, and resveratrol + LVH + IR groups. Myocardial hypertrophy and IR models were created by abdominal aortic banding and left coronary artery occlusion, respectively. To evaluate the electrocardiogram parameters and incidence of arrhythmias, electrocardiogram was recorded by subcutaneous leads (lead II). Blood pressure was measured through the left carotid artery. Infarct size was determined by the triphenyl tetrazolium chloride staining. The Ang (1-7) level was evaluated by immunohistochemistry. The Mas receptor mRNA level was assessed by the real-time real time reverse transcription polymerase chain reaction technique. QT-interval duration, infarct size, and incidence of ischemia-induced arrhythmia were significantly higher in the LVH + IR group. However, in the resveratrol-treated group, these parameters were decreased significantly. The cardiac level of Ang (1-7) was decreased in untreated hypertrophied hearts (LVH and LVH + IR groups). Pretreatment with resveratrol normalized the cardiac level of Ang (1-7). The mRNA level of Mas receptor was increased in all of hypertrophied hearts in the presence or absence of resveratrol. Resveratrol can decrease IR injury in rats with LVH. The anti-ischemic effect of resveratrol may be related to the enhancement of Ang (1-7)/MasR axis.

A trans locus causes a ribosomopathy in hypertrophic hearts that affects mRNA translation in a protein length-dependent fashion

BackgroundLittle is known about the impact of trans-acting genetic variation on the rates with which proteins are synthesized by ribosomes. Here, we investigate the influence of such distant genetic loci on the efficiency of mRNA translation and define their contribution to the development of complex disease phenotypes within a panel of rat recombinant inbred lines.ResultsWe identify several tissue-specific master regulatory hotspots that each control the translation rates of multiple proteins. One of these loci is restricted to hypertrophic hearts, where it drives a translatome-wide and protein length-dependent change in translational efficiency, altering the stoichiometric translation rates of sarcomere proteins. Mechanistic dissection of this locus across multiple congenic lines points to a translation machinery defect, characterized by marked differences in polysome profiles and misregulation of the small nucleolar RNA SNORA48. Strikingly, from yeast to humans, we observe reproducible protein length-dependent shifts in translational efficiency as a conserved hallmark of translation machinery mutants, including those that cause ribosomopathies. Depending on the factor mutated, a pre-existing negative correlation between protein length and translation rates could either be enhanced or reduced, which we propose to result from mRNA-specific imbalances in canonical translation initiation and reinitiation rates.ConclusionsWe show that distant genetic control of mRNA translation is abundant in mammalian tissues, exemplified by a single genomic locus that triggers a translation-driven molecular mechanism. Our work illustrates the complexity through which genetic variation can drive phenotypic variability between individuals and thereby contribute to complex disease.

Neuraminidase 1 is a driver of experimental cardiac hypertrophy.

Despite considerable therapeutic advances, there is still a dearth of evidence on the molecular determinants of cardiac hypertrophy that culminate in heart failure. Neuraminidases are a family of enzymes that catalyze the cleavage of terminal sialic acids from glycoproteins or glycolipids. This study sought to characterize the role of neuraminidases in pathological cardiac hypertrophy and identify pharmacological inhibitors targeting mammalian neuraminidases. Neuraminidase 1 (NEU1) was highly expressed in hypertrophic hearts of mice and rats, and this elevation was confirmed in patients with hypertrophic cardiomyopathy (n = 7) compared with healthy controls (n = 7). The increased NEU1 was mainly localized in cardiomyocytes by co-localization with cardiac troponin T. Cardiomyocyte-specific NEU1 deficiency alleviated hypertrophic phenotypes in response to transverse aortic constriction or isoproterenol hydrochloride infusion, while NEU1 overexpression exacerbated the development of cardiac hypertrophy. Mechanistically, co-immunoprecipitation coupled with mass spectrometry, chromatin immunoprecipitation, and luciferase assays demonstrated that NEU1 translocated into the nucleus and interacted with GATA4, leading to Foetal gene (Nppa and Nppb) expression. Virtual screening and experimental validation identified a novel compound C-09 from millions of compounds that showed favourable binding affinity to human NEU1 (KD = 0.38 μM) and effectively prevented the development of cardiac remodelling in cellular and animal models. Interestingly, anti-influenza drugs zanamivir and oseltamivir effectively inhibited mammalian NEU1 and showed new indications of cardio-protection. This work identifies NEU1 as a critical driver of cardiac hypertrophy and inhibition of NEU1 opens up an entirely new field of treatment for cardiovascular diseases.