Brain Natriuretic Peptide Expression Research Articles

Investigating the Role of Brain Natriuretic Peptide (BNP) and N-Terminal-proBNP in Thrombosis and Acute Ischemic Stroke Etiology.

The need for biomarkers for acute ischemic stroke (AIS) to understand the mechanisms implicated in pathological clot formation is critical. The levels of the brain natriuretic peptides known as brain natriuretic peptide (BNP) and NT-proBNP have been shown to be increased in patients suffering from heart failure and other heart conditions. We measured their expression in AIS clots of cardioembolic (CE) and large artery atherosclerosis (LAA) etiology, evaluating their location inside the clots, aiming to uncover their possible role in thrombosis. We analyzed 80 thrombi from 80 AIS patients in the RESTORE registry of AIS clots, 40 of which were of CE and 40 of LAA etiology. The localization of BNP and NT-BNP, quantified using immunohistochemistry and immunofluorescence, in AIS-associated white blood cell subtypes was also investigated. We found a statistically significant positive correlation between BNP and NT-proBNP expression levels (Spearman's rho = 0.668 p < 0.0001 *). We did not observe any statistically significant difference between LAA and CE clots in BNP expression (0.66 [0.13-3.54]% vs. 0.53 [0.14-3.07]%, p = 0.923) or in NT-proBNP expression (0.29 [0.11-0.58]% vs. 0.18 [0.05-0.51]%, p = 0.119), although there was a trend of higher NT-proBNP expression in the LAA clots. It was noticeable that BNP was distributed throughout the thrombus and especially within platelet-rich regions. However, NT-proBNP colocalized with neutrophils, macrophages, and T-lymphocytes, suggesting its association with the thrombo-inflammatory process.

Comparison of Protective Effect of Tri-circulator and Coenzyme Q10 on Myocardial Injury and the Mechanism Study by Zebrafish Model.

Tri-Circulator (TC) is a product comprising coenzyme Q10 (CoQ10), Salvia miltiorrhiza, and Panax notoginseng. Individually, each of these constituents has demonstrated protective effects on myocardial injury. The purpose of this study is to evaluate the protective efficacy of TC on heart function and compare the differential effects between CoQ10 and TC. Two myocardial injury models of zebrafish, the hypoxia-reoxygenation model (H/R) and the isoproterenol (ISO, a β-receptor agonist) model, were used in this experiment. The zebrafish subjects were divided into 4 groups: control, H/R, TC, and CoQ10. Heart rate, stroke volume (SV), cardiac output (CO), ejection fraction (EF), fractional area change (FAC), and pericardial height were monitored to assess changes in heart function. The gene expression of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) was studied as markers of injury/stress. TC significantly suppresses elevated heart rate induced by H/R and prevents the decrease of heart rate induced by ISO. It alleviates the pericardial infusion induced by ISO, whereas CoQ10 does not possess a similar effect. Both TC and CoQ10 significantly inhibit the decline in SV, CO, EF, and FAC induced by H/R and ISO, and suppress the expression of ANP and BNP in cardiomyocytes induced by ISO. It is noteworthy that TC demonstrates a more pronounced effect on EF, FAC, ANP, and BNP gene expression compared to CoQ10. Both TC and CoQ10 have a protective effect on myocardial injury of zebrafish. However, TC exhibits a greater efficacy compared to CoQ10 alone in mitigating myocardial injury.

Effect and mechanism of Linggui Zhugan Decoction in regulating Sig1R on AngⅡ-induced cardiomyocyte hypertrophy

This study aims to explore the mechanism of Linggui Zhugan Decoction(LGZGD) in inhibiting Angiotensin Ⅱ(AngⅡ)-induced cardiomyocyte hypertrophy by regulating sigma-1 receptor(Sig1R). The model of H9c2 cardiomyocyte hypertrophy induced by AngⅡ in vitro was established by preparing LGZGD-containing serum and blank serum. H9c2 cells were divided into normal group, AngⅡ model group, 20% normal rat serum group(20% NSC), and 20% LGZGD-containing serum group. After the cells were incubated with AngⅡ(1 μmol·L~(-1)) or AngⅡ with serum for 72 h, the surface area of cardiomyocytes was detected by phalloidine staining, and the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase were detected by micromethod. The mitochondrial Ca~(2+) levels were detected by flow cytometry, and the expression levels of atrial natriuretic peptide(ANP), brain natriuretic peptide(BNP), Sig1R, and inositol 1,4,5-triphosphate receptor type 2(IP_3R_2) were detected by Western blot. The expression of Sig1R was down-regulated by transfecting specific siRNA for investigating the efficacy of LGZGD-containing serum on cardiomyocyte surface area, Na~+-K~+-ATPase activity, Ca~(2+)-Mg~(2+)-ATPase activity, mitochondrial Ca~(2+), as well as ANP, BNP, and IP_3R_2 protein expressions. The results showed that compared with the normal group, AngⅡ could significantly increase the surface area of cardiomyocytes and the expression of ANP and BNP(P&lt;0.01), and it could decrease the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase, the concentration of mitochondrial Ca~(2+), and the expression of Sig1R(P&lt;0.01). In addition, IP_3R_2 protein expression was significantly increased(P&lt;0.01). LGZGD-containing serum could significantly decrease the surface area of cardiomyocytes and the expression of ANP and BNP(P&lt;0.05, P&lt;0.01), and it could increase the activities of Na~+-K~+-ATPase and Ca~(2+)-Mg~(2+)-ATPase, the concentration of mitochondrial Ca~(2+ )(P&lt;0.01), and the expression of Sig1R(P&lt;0.05). In addition, IP_3R_2 protein expression was significantly decreased(P&lt;0.05). However, after Sig1R was down-regulated, the effects of LGZGD-containing serum were reversed(P&lt;0.01). These results indicated that the LGZGD-containing serum could inhibit cardiomyocyte hypertrophy induced by AngⅡ, and its pharmacological effect was related to regulating Sig1R, promoting mitochondrial Ca~(2+ )inflow, restoring ATP synthesis, and protecting mitochondrial function.

Resveratrol alleviates hyperglycemia-induced cardiomyocyte hypertrophy by maintaining mitochondrial homeostasis via enhancing SIRT1 expression

To investigate whether resveratrol alleviates hyperglycemia-induced cardiomyocyte hypertrophy by enhancing the expression of silent information regulation 2 homolog 1 (SIRT1) to maintain mitochondrial homeostasis. Rat cardiomyocytes H9c2 cells with or without lentivirus-mediated mRNA interference of SIRT1 were cultured in high glucose (HG) and treated with resveratrol for 72 h. The changes in superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, reactive oxygen species (ROS) level, and relative surface of the cells were examined, and the mRNA expressions of atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) and protein expressions of SIRT1, mitochondrial fusion related proteins optic atrophy protein 1 (OPA1) and mitofusin 2, mitochondrial division related proteins dynamin-related protein 1 (DRP1) and fission protein 1 (FIS1), and mitophagy-related proteins BNIP3L and LC3 were detected using RT-qPCR and Western blotting. HG exposure significantly decreased SOD activity, increased MDA content, ROS production, relative cell surface, and the mRNA expressions of ANF and BNP in the cardiomyocytes; the protein expressions of SIRT1, OPA1, mitofusin 2 and BNIP3L and LC3-Ⅱ/LC3-Ⅰ ratio were all decreased and the protein expressions of DRP1 and FIS1 increased in HG-exposed cells (P<0.01). All these changes in HG-exposed cardiomyocytes were significantly alleviated by treatment with resveratrol (P<0.05). The protective effects of resveratrol against HG exposure in the cardiomyocytes were obviously attenuated by transfection of the cells with si-SIRT1 (P<0.05). Resveratrol inhibits hyperglycemia-induced cardiomyocyte hypertrophy by reducing oxidative stress, the mechanisms of which involve enhancement of SIRT1 protein expression, regulation of mitochondrial fusion and division balance, and promoting BNIP3L-mediated mitophagy to maintain mitochondrial homeostasis in the cells.

Triptolide attenuates cardiac remodeling by inhibiting pyroptosis and EndMT via modulating USP14/Keap1/Nrf2 pathway

BackgroundCardiac remodeling is a common pathological feature in many cardiac diseases, characterized by cardiac hypertrophy and fibrosis. Triptolide (TP) is a natural compound derived from Tripterygium wilfordii Hook F. However, the related mechanism of it in cardiac remodeling has not been fully understood. Methods and resultsTransverse aortic constriction (TAC)-induced cardiac hypertrophic mouse model and angiotensin II (Ang II)-induced cardiomyocytes hypertrophic model were performed. Firstly, the results indicate that TP can improve cardiac function, decreased cardiomyocyte surface area and fibrosis area, as well as lowered the protein expressions of brain natriuretic peptide (BNP), β-major histocompatibility complex (β-MHC), type I and III collagen (Col I and III). Secondly, TP suppressed cardiac pyroptosis, and decreased the levels of Interleukin-1β (IL-1β), Interleukin-18 (IL-18) by Enzyme-linked immunosorbent assay (ELISA), and pyroptosis-associated proteins. Furthermore, TP enhanced the expressions of Nuclear factor erythroid 2-related factor 2 (Nrf2) and Heme oxygenase 1 (HO-1). Interestingly, when Nrf2 was silenced by siRNA, TP lost its properties of reducing pyroptosis and cardiac hypertrophy. In addition, in the Transforming Growth Factor β1 (TGF-β1)-induced primary human coronary artery endothelial cells (HCAEC) model, TP was found to inhibit the process of endothelial-to-mesenchymal transition (EndMT), characterized by the loss of endothelial-specific markers and the gain of mesenchymal markers. This was accompanied by a suppression of Slug, Snail, and Twist expression. Meanwhile, the inhibitory effect of TP on EndMT was weakened when Nrf2 was silenced by siRNA. Lastly, potential targets of TP were identified through network pharmacology analysis, and found that Ubiquitin-Specific Protease 14 (USP14) was one of them. Simultaneously, the data indicated that decrease the upregulation of USP14 and Kelch-like ECH-Associated Protein 1 (Keap1) caused by cardiac remodeling. However, Keap1 was decreased and Nrf2 was increased when USP14 was silenced. Furthermore, CoIP analysis showed that USP14 directly interacts with Keap1. ConclusionTP can observably reduce pyroptosis and EndMT by targeting the USP14/Keap1/Nrf2 pathway, thereby significantly attenuating cardiac remodeling.

Therapeutic effect of adipose-derived stem cells injected into pericardial cavity in rat heart failure.

There are few studies on the treatment of heart failure by injecting stem cells into the pericardial cavity. Can the cells injected into the pericardial cavity migrate through the epicardium to the myocardial tissue? Whether there is therapeutic effect and the mechanism of therapeutic effect are still unclear. This study investigated the therapeutic efficacy and evidence of cell migration of adipose-derived stem cells (ADSCs) injected into the pericardial cavity in rat heart failure. The aim of this study is to demonstrate the effectiveness and mechanism of treating heart failure by injecting stem cells into the pericardial cavity, laying an experimental foundation for a new approach to stem cell therapy for heart disease in clinical practice. The inguinal adipose tissue of male SD rats aged 4-6weeks was taken, ADSCs were isolated and cultured, and their stem cell surface markers were identified. Forty rats aged 6-8weeks were divided into sham operation group, heart failure group, and treatment group; there were 15 rats in the heart failure group and 15 rats in the treatment group. The heart failure model was established by intraperitoneal injection of adriamycin hydrochloride. The heart function of the three groups was detected by small animal ultrasound. The model was successful if the left ventricular ejection fraction<50%. The identified ADSCs were injected into the pericardial cavity of rats in the treatment group. The retention of transplanted cells in pericardial cavity was detected by small animal in vivo imaging instrument, and the migration of transplanted cells into myocardial tissue was observed by tissue section and immunofluorescence. Western blotting and immunohistochemical staining were used to detect brain natriuretic peptide (BNP), α-smooth muscle actin (α-SMA), and C-reactive protein (CRP). ADSCs express CD29, CD44, and CD73. On the fourth day after injection of ADSCs into pericardial cavity, they migrated to myocardial tissue through epicardium and gradually diffused to deep myocardium. The cell density in the pericardial cavity remains at a high level for 10days after injection and gradually decreases after 10days. Compared with the heart failure group, the expression of BNP and α-SMA decreased (P<0.05 and P<0.001, respectively), and the expression of CRP in the treatment group was higher than that in the heart failure group (P<0.0001). A small amount of BNP, α-SMA, and CRP was expressed in the myocardium of the sham operation group. After injection of ADSCs, interleukin-6 in myocardial tissue was significantly lower than that in heart failure myocardium (P<0.01). After treatment, vascular endothelial growth factor A was significantly higher than that of heart failure (P<0.01). Pericardial cavity injected ADSCs can penetrate the epicardium, migrate into the myocardium, and have a therapeutic effect on heart failure. Their mechanism of action is to exert therapeutic effects through anti-inflammatory, anti-fibrosis, and increased angiogenesis.

Spatial transcriptomic analysis identifies a border zone with localized expression of brain natriuretic peptide in the inferobasal region of the left ventricle in patients with mitral valve prolapse

Abstract Background/Introduction Mitral valve prolapse (MVP) is a common cause of mitral regurgitation (MR), adverse left ventricular (LV) remodeling and arrhythmias. MVP induces mechanical stretch to the inferobasal (IB) myocardium and papillary muscles. The underlying regional and molecular pathology of MVP-induced LV remodeling remains incompletely understood. Purpose The aim was to characterize the molecular effects of mechanical stretch by comparing the regional gene expression of the IB region of LV with the interventricular septum in patients with MVP. Methods Myocardial biopsies were obtained from the IB LV (i.e. between papillary muscles) and the interventricular septum during mitral valve repair surgery for MVP-induced primary MR. The degree of cardiac fibrosis was detected and quantified by histology. We used spatial transcriptomics (ST) that - in contrast to traditional analyses of tissue homogenates - allows regional expressional analysis. Results Automated clustering of ST results correlated with histological staining of fibrosis in the IB and septal regions (R=0.97, P&amp;lt;0.0001), demonstrating good automated identification of fibrotic regions. The extent of fibrosis was similar between the inferobasal region and the septal control in the respective patients with MVP as determined by histological analysis and ST. The localized fibrotic areas of the inferobasal region showed decreased expression of cardiac myocytegenes such as RYR2, TNNI3, TNNC1 or TPM1, and increased expression of fibrous and EndMT markers such as COL3A1, BGN, SM22 or FN1. In the IB region, we identified a transition zone between healthy myocardium and fibrous tissue. This transition zone showed increased expression of the NPPB gene encoding brain natriuretic peptide (BNP), whereas NPPB was not increased in the septal region of the same patients. The upregulation of NPPB (6.4-fold, P=0.004) in the inferobasal region compared to the septal control was confirmed by qPCR in biopsies from patients with MVP. The identified transition zones were characterized by increased expression of genes such as IGFBP2 and LTBP2, which have been described to be associated with adverse LV remodeling in heart failure. Interestingly, the serum NT-proBNP levels (mean 276.8 ± 121.6 pg/ml) of the patients correlated with NPPB levels from the inferobasal region (R=0.76, P=0.01, N=9), whereas no correlation was found with NPPB levels from the septal control regions (R=0.17, P=0.65) of the same patients. Conclusions ST analysis in MVP identifies a transition zone of the inferobasal region of LV which is exposed to high mechanical stretch. This transition zone - but not the inferobasal fibrotic area nor the LV septum - is characterized by a specific increase in NBBP expression that correlates with increased NT-ProBNP serum concentrations. These special sequencing results indicate that mechanical stretch induces highly localized myocardial pathologies with systemic consequences.

Inhibition of ADAM10-mediated CX3CL1 shedding promotes survival and cardiac function early after myocardial infarction

Abstract Background and Purpose The metalloprotease ADAM10 has been implicated in immune regulatory processes, is upregulated in response to specific heart pathologies e.g. ischemic heart failure, and elevated serum levels of the ADAM10 substrates CX3CL1 and CXCL16 have been reported following infarction. The causal role of ADAM10 in cardiovascular diseases, however, is not known yet. By using human tissue biopsies, a cardiomyocyte-specific ADAM10 knockout mouse model (ADAM10 KO), and pharmacological ADAM10 inhibition we here comprehensively characterize the role of ADAM10 in the heart and in cardiac disease. Methods and Results We show that ADAM10 protein levels are upregulated in patients with ischemic cardiomyopathy (2.5-fold) and ADAM10 mRNA expression correlates with expression of atrial (NPPA) and brain natriuretic peptide (NPPB) mRNA. Upon infarction, ADAM10 expression is specifically induced in cardiomyocytes, and cardiomyocyte-specific ADAM10 KO as well as pharmacological inhibition (GI254023X) for only three days significantly improves overall survival, reduces scar size, and preserves cardiac function. Mechanistically, flow cytometry and bulk RNA sequencing identify a ADAM10/CX3CL1 axis to control neutrophil bone marrow egress and heart tissue infiltration after infarction. Diminished neutrophil migration results in long-term reduction of IL-1β-driven inflammation. Using cell culture experiments with ADAM10/CX3CL1 knockdown cardiomyocytes, we show that ADAM10-mediated ectodomain shedding of CX3CL1 specifically regulates neutrophil but not macrophage chemotaxis revealing a novel conceptual insight into how acute infarction triggers chemotactic signaling via ectodomain shedding. Conclusion Pharmacological and genetic targeting of the membrane sheddase ADAM10 is highly efficient for improving post-infarction cardiac function and survival via abolished post-translational CX3CL1 processing, neutrophil infiltration and IL-1β-dependent inflammation. Thus, our data reveal a novel therapeutic concept, which may close a clinically relevant therapeutic gap early after myocardial infarction.

Pogostone alleviates angiotensin II-induced cardiomyocyte hypertrophy in H9c2 cells through MAPK and Nrf2 pathway

Purpose: To investigate the effect of pogostone on cardiac hypertrophy.Methods: An in vitro model of myocardial hypertrophy was first established by stimulating H9c2 (rat cardiomyocytes) with angiotensin II (Ang II), and the cells treated with or without pogostone. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were measured by western blot. Immunofluorescence staining was performed for α-actinin while cell surface area was quantified. Dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescent probe and malondialdehyde (MDA) assay kit were used to determine reactive oxygen species (ROS) and MDA levels respectively. Apoptosis was evaluated by flow cytometry while Nrf2, p38, ERK, and JNK protein expression levels were determined by western-blot assay.Results: Compared with the control group, ANP and BNP protein expression levels, cell surface area, ROS, MDA, and apoptosis were all elevated in H9c2 cells after stimulation with Ang II (p &lt; 0.001). Varying doses of pogostone decreased protein expressions of ANP and BNP, reduced cell surface area, decreased ROS and MDA levels, and inhibited apoptosis. Pogostone also up-regulated and inhibited the phosphorylation levels of p38 and ERK, and JNK levels in H9c2 cells.Conclusion: Pogostone reduces protein expression of ANP and BNP and up-regulated Nrf2 protein expression in H9c2 cells stimulated with angiotensin II.

Eleutheroside E from pre-treatment of Acanthopanax senticosus (Rupr.etMaxim.) Harms ameliorates high-altitude-induced heart injury by regulating NLRP3 inflammasome-mediated pyroptosis via NLRP3/caspase-1 pathway.

Eleutheroside E, a major natural bioactive compound in Acanthopanax senticosus (Rupr.etMaxim.) Harms, possesses anti-oxidative, anti-fatigue, anti-inflammatory, anti-bacterial and immunoregulatory effects. High-altitude hypobaric hypoxia affects blood flow and oxygen utilisation, resulting in severe heart injury that cannot be reversed, thereby eventually causing or exacerbating high-altitude heart disease and heart failure. The purpose of this study was to determine the cardioprotective effects of eleutheroside E against high-altitude-induced heart injury (HAHI), and to study the mechanisms by which this happens. A hypobaric hypoxia chamber was used in the study to simulate hypobaric hypoxia at the high altitude of 6000m. 42 male rats were randomly assigned to 6 equal groups and pre-treated with saline, eleutheroside E 100mg/kg, eleutheroside E 50mg/kg, or nigericin 4mg/kg. Eleutheroside E exhibited significant dose-dependent effects on a rat model of HAHI by suppressing inflammation and pyroptosis. Eleutheroside E downregulated the expressions of brain natriuretic peptide (BNP), creatine kinase isoenzymes (CK-MB) and lactic dehydrogenase (LDH). Moreover, The ECG also showed eleutheroside E improved the changes in QT interval, corrected QT interval, QRS interval and heart rate. Eleutheroside E remarkably suppressed the expressions of NLRP3/caspase-1-related proteins and pro-inflammatory factors in heart tissue of the model rats. Nigericin, known as an agonist of NLRP3 inflammasome-mediated pyroptosis, reversed the effects of eleutheroside E. Eleutheroside E prevented HAHI and inhibited inflammation and pyroptosis via the NLRP3/caspase-1 signalling pathway. Taken together, eleutheroside E is a prospective, effective, safe and inexpensive agent that can be used to treat HAHI.

Tropisetron restores normal expression of BAD, SIRT1, SIRT3, and SIRT7 in the rat pressure overload-induced cardiac hypertrophy model.

Tropisetron exerts a protective effect against cardiac complications, particularly cardiac hypertrophy. Oxidative stress and apoptosis are the main contributors to the pathogenesis of cardiac hypertrophy. Sirtuins, a family of histone deacetylases, are connected to cellular oxidative stress signaling and antioxidant defense. Sirtuins are also linked to apoptosis which is an important mechanism in the progression of cardiac hypertrophy to heart failure. Literature also suggests that tropisetron impedes apoptosis, partly mediated through an antioxidant mechanism. Therefore, we examined if tropisetron fights cardiac hypertrophy by adjusting sirtuin family proteins (Sirts) and components of mitochondrial death pathway, Bcl-associated X (BAX), Bcl-2-associated death promoter (BAD). Male Sprague-Dawley rats got divided into four groups, including control (Ctl), tropisetron (Trop), cardiac hypertrophy (Hyp), and hypertrophic rats under tropisetron treatment (Hyp + Trop). Pathological cardiac hypertrophy was induced by surgical abdominal aortic constriction (AAC). The increased expression of brain natriuretic peptide (BNP) in the Hyp group confirms the cardiac hypertrophy establishment. The mRNA levels of SIRT1, SIRT3, SIRT7, and BAD also upregulated in the hypertrophic group (p < 0.001). Postoperational administration of tropisetron for 3 weeks lowered the increased expression of BNP (p < 0.05) and BAD (p < 0.001), though the reduction of BAX expression was statistically insignificant (p > 0.05). Tropisetron treatment also restored the normal level of SIRT1/3/7 genes expression in the Hyp + Trop group (p < 0.05). Present findings suggest that tropisetron can suppress cardiomyocyte hypertrophy progression to heart failure by counteracting BNP, SIRT1, SIRT3, Sirt7, and BAD overexpression-mediated apoptosis in a rat model of cardiac hypertrophy.

Long-term administration of Western diet induced metabolic syndrome in mice and causes cardiac microvascular dysfunction, cardiomyocyte mitochondrial damage, and cardiac remodeling involving caveolae and caveolin-1 expression

BackgroundLong-term consumption of an excessive fat and sucrose diet (Western diet, WD) has been considered a risk factor for metabolic syndrome (MS) and cardiovascular disease. Caveolae and caveolin-1 (CAV-1) proteins are involved in lipid transport and metabolism. However, studies investigating CAV-1 expression, cardiac remodeling, and dysfunction caused by MS, are limited. This study aimed to investigate the correlation between the expression of CAV-1 and abnormal lipid accumulation in the endothelium and myocardium in WD-induced MS, and the occurrence of myocardial microvascular endothelial cell dysfunction, myocardial mitochondrial remodeling, and damage effects on cardiac remodeling and cardiac function.MethodsWe employed a long-term (7 months) WD feeding mouse model to measure the effect of MS on caveolae/vesiculo-vacuolar organelle (VVO) formation, lipid deposition, and endothelial cell dysfunction in cardiac microvascular using a transmission electron microscopy (TEM) assay. CAV-1 and endothelial nitric oxide synthase (eNOS) expression and interaction were evaluated using real-time polymerase chain reaction, Western blot, and immunostaining. Cardiac mitochondrial shape transition and damage, mitochondria-associated endoplasmic reticulum membrane (MAM) disruption, cardiac function change, caspase-mediated apoptosis pathway activation, and cardiac remodeling were examined using TEM, echocardiography, immunohistochemistry, and Western blot assay.ResultsOur study demonstrated that long-term WD feeding caused obesity and MS in mice. In mice, MS increased caveolae and VVO formation in the microvascular system and enhanced CAV-1 and lipid droplet binding affinity. In addition, MS caused a significant decrease in eNOS expression, vascular endothelial cadherin, and β-catenin interactions in cardiac microvascular endothelial cells, accompanied by impaired vascular integrity. MS-induced endothelial dysfunction caused massive lipid accumulation in the cardiomyocytes, leading to MAM disruption, mitochondrial shape transition, and damage. MS promoted brain natriuretic peptide expression and activated the caspase-dependent apoptosis pathway, leading to cardiac dysfunction in mice.ConclusionMS resulted in cardiac dysfunction, remodeling by regulating caveolae and CAV-1 expression, and endothelial dysfunction. Lipid accumulation and lipotoxicity caused MAM disruption and mitochondrial remodeling in cardiomyocytes, leading to cardiomyocyte apoptosis and cardiac dysfunction and remodeling.

Blocking Store-Operated Ca2+ Entry to Protect HL-1 Cardiomyocytes from Epirubicin-Induced Cardiotoxicity.

Epirubicin (EPI) is one of the most widely used anthracycline chemotherapy drugs, yet its cardiotoxicity severely limits its clinical application. Altered intracellular Ca2+ homeostasis has been shown to contribute to EPI-induced cell death and hypertrophy in the heart. While store-operated Ca2+ entry (SOCE) has recently been linked with cardiac hypertrophy and heart failure, its role in EPI-induced cardiotoxicity remains unknown. Using a publicly available RNA-seq dataset of human iPSC-derived cardiomyocytes, gene analysis showed that cells treated with 2 µM EPI for 48 h had significantly reduced expression of SOCE machinery genes, e.g., Orai1, Orai3, TRPC3, TRPC4, Stim1, and Stim2. Using HL-1, a cardiomyocyte cell line derived from adult mouse atria, and Fura-2, a ratiometric Ca2+ fluorescent dye, this study confirmed that SOCE was indeed significantly reduced in HL-1 cells treated with EPI for 6 h or longer. However, HL-1 cells presented increased SOCE as well as increased reactive oxygen species (ROS) production at 30 min after EPI treatment. EPI-induced apoptosis was evidenced by disruption of F-actin and increased cleavage of caspase-3 protein. The HL-1 cells that survived to 24 h after EPI treatment demonstrated enlarged cell sizes, up-regulated expression of brain natriuretic peptide (a hypertrophy marker), and increased NFAT4 nuclear translocation. Treatment by BTP2, a known SOCE blocker, decreased the initial EPI-enhanced SOCE, rescued HL-1 cells from EPI-induced apoptosis, and reduced NFAT4 nuclear translocation and hypertrophy. This study suggests that EPI may affect SOCE in two phases: the initial enhancement phase and the following cell compensatory reduction phase. Administration of a SOCE blocker at the initial enhancement phase may protect cardiomyocytes from EPI-induced toxicity and hypertrophy.

VDR Regulates BNP Promoting Neurite Growth and Survival of Cochlear Spiral Ganglion Neurons through cGMP-PKG Signaling Pathway

Spiral ganglion neurons (SGNs) are important for hearing, and their peripheral and central processes connect sensory cells of the Corti organ to the central nervous system. The resulting network forms a point-to-point auditory conduction. As a cardiac hormone, brain natriuretic peptide (BNP) binds to natriuretic peptide receptor type A leading to diuresis, vasodilatation, inhibition of renin and aldosterone production, and cardiac and vascular myocyte growth. This study primarily aimed to explore the expression and function of BNP in the rat's inner ear and elucidate its regulatory mechanism. We determined the expression and function of BNP and found that the vitamin D receptor (VDR) could upregulate the expression of BNP and enhance its function. In SGNs of the rat inner ear, BNP promotes neuron survival and prolongs neurite length through the cGMP-PKG signaling pathway, which could be regulated by VDR and provide a novel approach for neuronal regeneration therapy. To the best of our knowledge, this is the first study to report this potential transcriptional regulatory relationship and will act as a reference for research on neuronal regeneration therapy for SGNs injury.

S1P lyase inhibition improves post-ischemic cardiac remodeling independently of infarct size via S1P receptor 1

Abstract Background Revascularization of the infarct vessel is the golden standard in acute myocardial infarction (AMI). Even in Western countries, more than ten percent of AMI patients are so-called “latecomers” and it is controversial if revascularization of the infarct vessel is beneficial in these patients. Current guidelines even discourage revascularization of the infarcted artery if symptom onset was &amp;gt;48 hours and the patient is asymptomatic. These patients are at high risk for cardiovascular events and heart failure with reduced ejection fraction (HFrEF). HFrEF has an enormous socio-economic impact, high morbidity, and mortality. Purpose Therapeutic options targeting post-ischemic cardiac remodeling are sparse. The bioactive sphingolipid sphingosine-1-phosphate (S1P) reduces ischemia/reperfusion injury when administered in advance. However, its impact on post-ischemic remodeling independently of its infarct size (IS)-reducing effect is yet unknown. Methods Acute myocardial infarction (AMI) in mice was induced by permanent ligation of the left anterior descending artery (LAD). C57Bl/6J were treated with the S1P lyase inhibitor 4-deoxypyridoxine (DOP) starting seven days prior to AMI to increase endogenous S1P concentrations. Cardiac function and myocardial healing were assessed by cardiovascular magnetic resonance imaging (cMRI), histomorphology and gene expression analysis. DOP effects were investigated in cardiomyocyte-specific S1P receptor 1 deficient (S1PR1 Cardio Cre+ and Cre− control) mice, and S1P concentrations measured by LC-MS/MS. Results S1P concentrations in plasma before induction of AMI were increased fourfold by DOP (Control 0.97±0.09μM [n=6] vs. DOP 3,80±0,09μM [n=6]). Scar size determined by MRI, as well as ejection fraction (EF), did not differ 24 h post AMI. In contrast, after 21 days, there was a clear difference between the two groups (scar size vehicle: 19.3±6.2% vs. DOP 13.4±5.7%; EF: Vehicle: 26.4±8.7% vs. DOP 38.2±11.8%). In addition, in the remote area 21 days post AMI in the DOP-treated animals, a reduced gene expression of brain natriuretic peptide, atrial natriuretic peptide and collagen 1a2. Finally, cardiomyocyte diameter in the remote myocardium was 21% smaller in DOP-treated (Vehicle: 21.95±1.59μm vs. DOP 17.35±0.77μm). The benefit of DOP-treatment was abolished in cardiomyocyte-specific S1PR1-deficient mice. Conclusion S1P improves cardiac function and myocardial healing post AMI independently of initial infarct size via S1PR1. Hence, in addition to its beneficial effects on I/R injury, S1PR1 may be a promising target in post-infarction myocardial remodeling as adjunctive therapy to revascularization and in patients who are not eligible for standard interventional procedures. Funding Acknowledgement Type of funding sources: None.

Effects of high-absorption curcumin for the prevention of hypertensive heart disease: a double-blind, placebo-controlled, randomized clinical study.

AimsHypertension is a strong risk factor for heart failure with preserved ejection fraction. Curcumin has p300-specific histone acetyltransferase inhibitory activity, suppresses cardiomyocyte hypertrophy and fibrosis, and significantly reduces myocardial brain natriuretic peptide (BNP) expression without altering blood pressure in a rat model of hypertensive heart disease. This double-blind, placebo-controlled, randomized study, for the first time, aimed to examine the efficacy of a high-absorption curcumin for the prevention of hypertensive heart disease in humans.Methods and resultsPatients exhibiting initial signs of hypertensive heart disease with left ventricular ejection fraction ≥60% and stable blood pressure <140/90 mmHg orally took a double-blinded capsule (either a 90 mg curcumin capsule or placebo) twice daily for 24 weeks. The primary endpoint was per cent changes in left ventricular diastolic function (E/E′) from baseline to 6 months after administration. The secondary endpoint was the per cent change in plasma BNP levels. The E/E′ ratio per cent change from baseline to 6 months after administration was similar between the placebo (n = 69) and the curcumin (n = 73) groups. The per cent change in plasma BNP levels was significantly lower in the curcumin group than in the placebo group. In patients <65 years, BNP per cent changes were significantly lower in the curcumin group than in the placebo group, but similar between groups in ≥65 years (<65 vs. ≥65 years: P for interaction = 0.011).ConclusionsA high-absorption curcumin agent did not affect the E/E′ ratio, rather it significantly inhibited the increase in plasma BNP levels in patients with initial signs of hypertensive heart disease.

Hydrogen Attenuates Thyroid Hormone-Induced Cardiac Hypertrophy in Rats by regulating angiotensin II type 1 receptor and NADPH oxidase 2 mediated oxidative stress

Cardiac hypertrophy occurs as a result of high levels of thyroid hormone, which may contribute to heart failure and is closely related to oxidative stress. Hydrogen is a good antioxidant. In this study, we found that intragastric levothyroxine administration for two weeks caused obvious cardiac hypertrophy without reduced systolic function. Additionally, hydrogen inhalation ameliorated the levothyroxine-induced metabolic increase and cardiac hypertrophy in rats. Serum brain natriuretic peptide expression was also attenuated by hydrogen treatment. However, hydrogen had no significant effect on levothyroxine -induced serum troponin I and serum thyroid hormone changes.Hydrogen treatment also reduced the levothyroxine-induced increase in cardiac malondialdehyde, 8-hydroxy-2-deoxyguanosine and serum hydrogen peroxide levels and upregulated superoxide dismutase and glutathione peroxidase activity. Additionally, western blotting results showed that hydrogen inhalation inhibited the expression of cardiac nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), angiotensin II type 1 receptor, sarcoplasmic reticulum Ca2+-ATPase (SERCA2), phospho-phospholamban and α-myosin heavy chain proteins. In conclusion, the present study revealed a protective effect of hydrogen on levothyroxine -induced cardiac hypertrophy by regulating angiotensin II type 1 receptors and NOX2-mediated oxidative stress in rats.

Serum-Induced Expression of Brain Natriuretic Peptide Contributes to Its Increase in Patients with HFpEF.

Brain natriuretic peptide (BNP) levels are increased in both patients with heart failure with preserved (HFpEF) and reduced ejection fraction (HFrEF), but the reasons for this remain unclear. Our purpose was to examine whether serum-induced BNP (iBNP) expression partly contributes to increased BNP in patients with HFpEF. BNP reporter cardiomyocytes from pBNP-luc-KI mice were stimulated with serum from patients with HFpEF or HFrEF (n = 114 and n = 82, respectively). Luciferase activity was examined as iBNP and the iBNP-to-BNP ratio was evaluated. Patient characteristics and clinical parameters were compared, and multivariate regression analysis was performed to determine independent predictors of the iBNP-to-BNP ratio. Female sex and frequencies of atrial fibrillation, hypertension and the use of a calcium channel blocker (CCB) were higher in HFpEF. The iBNP-to-BNP ratio was significantly higher in HFpEF (26.9) than in HFrEF (16.1, p < 0.001). Multivariate regression analysis identified the existence of HFpEF as an independent predictor of the iBNP-to-BNP ratio after adjusting for all other measurements (β = 0.154, p = 0.032). Age, hemoglobin, CCB usage and deceleration time were also independent predictors (β = 0.167, p = 0.025; β = 0.203, p = 0.006; β = 0.138, p = 0.049; and β = 0.143, p = 0.049, respectively). These results indicate that the elevated BNP in patients with HFpEF is partly due to iBNP from the heart.

Nicotinamide riboside kinase-2 inhibits JNK pathway and limits dilated cardiomyopathy in mice with chronic pressure overload

Nicotinamide riboside kinase-2 (NRK-2) has recently emerged as a critical regulator of cardiac remodeling however, underlying molecular mechanisms is largely unknown. To explore the same, NRK2 knockout (KO) and littermate control mice were subjected to trans-aortic constriction (TAC) or sham surgeries and cardiac function was assessed by serial M-mode echocardiography. A mild cardiac contractile dysfunction was observed in the KOs at the early adaptive phase of remodeling followed by a significant deterioration during the maladaptive cardiac remodeling phase. Consistently, NRK2 KO hearts displayed increased cardiac hypertrophy and heart failure (HF) reflected by morphometric parameters as well as increased fetal genes, atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) expressions. Histological assessment revealed an extensive left ventricular (LV) chamber dilatation accompanied by elevated cardiomyopathy (CM) and fibrosis in the KO hearts post-TAC. In a gain-of-function model, NRK-2 overexpressing in AC16 cardiomyocytes displayed significantly attenuated fetal genes ANP and BNP expression. Consistently, NRK-2 overexpression attenuated angiotensin II (Ang II)-induced cardiomyocyte death. Mechanistically, we identified NRK-2 as a regulator of c-jun N-terminal kinase (JNK) MAP kinase and mitochondrial function where NRK-2 overexpression in human cardiomyocytes markedly suppressed the Ang II-induced JNK activation and mitochondrial depolarization. Thus, our results demonstrate that NRK-2 plays protective roles in pressure overload (PO)-induced dilatative cardiac remodeling and, genetic ablation exacerbates dilated cardiomyopathy (DCM), interstitial collagen deposition, and cardiac dysfunction post-TAC due, in part, to increased JNK activation and mitochondrial dysfunction.

Dapagliflozin Ameliorates STZ-Induced Cardiac Hypertrophy in Type 2 Diabetic Rats by Inhibiting the Calpain-1 Expression and Nuclear Transfer of NF-κB.

Objective To investigate the effect of dapagliflozin (DAPA) on cardiac hypertrophy induced by type 2 diabetes mellitus (T2DM) and its mechanism. Methods SD rats with T2DM were divided into a T2DM group (n = 6) and DAPA group (n = 6). They were, respectively, fed with the same amount of normal saline and 1 mg/kg DAPA. The control group (n = 6) was also fed with normal saline. The hearts were tested by the application of echocardiography and hemodynamics. Subsequently, fasting blood glucose (FBG), serum total cholesterol (TC), and triglyceride (TG) as well as interleukin- (IL-) 10, IL-6, and tumor necrosis factor (TNF)-α in serum were tested. H&E and Masson staining was performed to observe the degree of cardiac tissue lesions, and expression of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), calpain-1, p-IκBα, and p65 in myocardial tissue was tested by qRT-PCR and Western blot. Results Compared with the control group, rats in the T2DM group exhibited significant diabetic symptoms: FBG was significantly elevated, and the levels of TC, TG, IL-6, and TNF-α were significantly increased, while the levels of IL-10 and the calpain activity were evidently decreased. However, DAPA treatment could improve the above changes. At the same time, the damage and fibrosis of the heart tissue in the DAPA group were markedly improved. Additionally, the mRNA expression of ANP and BNP in myocardial tissue of the DAPA group was markedly increased. And DAPA could inhibit the expression of p-IκBα/IκBα in the cytoplasm and p65 in the nucleus as well as the expression of calpain-1 in myocardial tissue. Conclusion DAPA treatment ameliorates the cardiac hypertrophy caused by T2DM by decreasing body blood glucose, while reducing the expression of calpain-1 in cardiomyocytes and inhibiting the nuclear translocation of NF-κB.