Roles of cyclooxygenase-2 and phosphorylated Akt (Thr308) in cardiac hypertrophy regression mediated by left-ventricular unloading

Effects of Long-Term Administration of Bovine Bone Gelatin Peptides on Myocardial Hypertrophy in Spontaneously Hypertensive Rats

The research purpose was to investigate the effects and the underlying molecular mechanisms of bovine bone gelatin peptides (BGP) on myocardial hypertrophy in spontaneously hypertensive rats (SHR). BGP relieved myocardial hypertrophy and fibrosis in SHR rats in a dose-dependent manner by reducing the left ventricular mass index, myocardial cell diameter, myocardial fibrosis area, and levels of myocardial hypertrophy markers (atrial natriuretic and brain natriuretic peptide). Label-free quantitative proteomics analysis showed that long-term administration of BGP changed the left ventricle proteomes of SHR. The 37 differentially expressed proteins in the high-dose BGP group participated in multiple signaling pathways associated with cardiac hypertrophy and fibrosis indicating that BGP could play a cardioprotective effect on SHR rats by targeting multiple signaling pathways. Further validation experiments showed that a high dose of BGP inhibited the expression of phosphoinositide 3-kinase (Pi3k), phosphorylated protein kinase B (p-Akt), and transforming growth factor-beta 1 (TGF-β1) in the myocardial tissue of SHR rats. Together, BGP could be an effective candidate for functional nutritional supplements to inhibit myocardial hypertrophy and fibrosis by negatively regulating the TGF-β1 and Pi3k/Akt signaling pathways.

The role of autophagy in cardiovascular disease: Cross-interference of signaling pathways and underlying therapeutic targets

Autophagy is a conserved lysosomal pathway for the degradation of cytoplasmic proteins and organelles, which realizes the metabolic needs of cells and the renewal of organelles. Autophagy-related genes (ATGs) are the main molecular mechanisms controlling autophagy, and their functions can coordinate the whole autophagic process. Autophagy can also play a role in cardiovascular disease through several key signaling pathways, including PI3K/Akt/mTOR, IGF/EGF, AMPK/mTOR, MAPKs, p53, Nrf2/p62, Wnt/β-catenin and NF-κB pathways. In this paper, we reviewed the signaling pathway of cross-interference between autophagy and cardiovascular diseases, and analyzed the development status of novel cardiovascular disease treatment by targeting the core molecular mechanism of autophagy as well as the critical signaling pathway. Induction or inhibition of autophagy through molecular mechanisms and signaling pathways can provide therapeutic benefits for patients. Meanwhile, we hope to provide a unique insight into cardiovascular treatment strategies by understanding the molecular mechanism and signaling pathway of crosstalk between autophagy and cardiovascular diseases.

Exploring the Therapeutic Mechanism of Tingli Dazao Xiefei Decoction on Heart Failure Based on Network Pharmacology and Experimental Study

Background

Tingli Dazao Xiefei decoction (TDXD) has been shown to have a therapeutic effect on heart failure (HF). Nevertheless, its molecular mechanism for treating HF is still unclear.

Materials and Methods

TDXD and HF targets were collected from the databases, and protein-protein interaction (PPI) analysis and enrichment analysis were performed on the overlapping targets. Then, AutoDock was employed for molecular docking. Finally, we used the left anterior descending coronary artery (LAD) ligation to induce HF model rats for in vivo experiments and verified the effect and mechanism of TDXD on HF.

Results

Network pharmacological analysis showed that the main active components of TDXD in treating HF were quercetin, kaempferol, beta-carotene, isorhamnetin, and beta-sitosterol, and the core targets were IL-6, VEGFA, TNF, AKT1, and MAPK1. Multiple gene functions and signaling pathways were obtained by enrichment analysis, among which inflammation-related, PI3K/Akt, and MAPK signaling pathways were closely related to HF. Furthermore, the molecular docking results showed that the core targets had good binding ability with the main active components. Animal experiments showed that TDXD could effectively improve left ventricular ejection fraction (EF) and left ventricular fractional shortening (FS), decrease left ventricular internal diastolic diameter (LVIDd) and left ventricular internal systolic diameter (LVIDs), reduce the area of myocardial fibrosis, and decrease serum BNP, LDH, CK-MB, IL-6, IL-1β, and TNF-α levels in HF rats. Meanwhile, TDXD could upregulate the expression of Bcl-2, downregulate the expression of Bax, and reduce cardiomyocyte apoptosis. At the same time, it was verified that TDXD could significantly decrease the expression of PI3K, P-Akt, and P-MAPK. Captopril showed similar effects.

Conclusions

Combining network pharmacological analysis and experimental validation, this study verified that TDXD could improve cardiac function and protect against cardiac injury by inhibiting the activation of PI3K/Akt and MAPK signaling pathways.

Global comparison of phosphoproteins in human and rodent hearts: implications for translational studies of myosin light chain and troponin phosphorylations

Cardiac remodeling and failure are regulated by a myriad of cardiac protein phosphorylations. In the present study, cardiac phosphoprotein patterns were examined in rodent and human hearts Left ventricular tissue samples were obtained from human systolic failing (n = 5) and control (n = 5) hearts and from two rat models of hypertensive heart failure, i.e., spontaneously hypertensive heart failure and Dahl salt-sensitive rats and corresponding controls. Phosphoproteins were separated by 2D-DIGE with Cydye staining, phosphoprotein patterns were analyzed using pixel intensity in rectified images. Specific phosphoproteins which were different in human versus rodent hearts were identified by MALDI-TOF/TOF Mass Spectrometry. Targeted pair-wise analyses showed differences (p < 0.05) in 26 % of the pixels, which included pixels containing phosphorylated troponin T, myosin light chain, peroxiredoxin, and haptoglobin. These results show differences in rodent versus human cardiac remodeling which will influence the translation rodent studies to humans in this area.

Apelin-13 promotes cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy

Apelin is highly expressed in rat left ventricular hypertrophy Sprague Dawley rat models, and it plays a crucial role in the cardiovascular system. The aim this study was to clarify whether apelin-13 promotes hypertrophy in H9c2 rat cardiomyocytes and to investigate its underlying mechanism. The cardiomyocyte hypertrophy was observed by measuring the diameter, volume, and protein content of H9c2 cells. The activation of autophagy was evaluated by observing the morphology of autophagosomes by transmission electron microscopy, observing the subcellular localization of LC3 by light microscopy, and detecting the membrane-associated form of LC3 by western blot analysis. The phosphatidylinositol 3-kinase (PI3K) signaling pathway was identified and the proteins expression was detected using western blot analysis. The results revealed that apelin-13 increased the diameter, volume, and protein content of H9c2 cells and promoted the phosphorylation of PI3K, Akt, ERK1/2, and p70S6K. Apelin-13 activated the PI3K-Akt-ERK1/2-p70S6K pathway. PI3K inhibitor LY294002, Akt inhibitor 1701-1, ERK1/2 inhibitor PD98059 attenuated the increase of the cell diameter, volume, protein content induced by apelin-13. Apelin-13 increased the autophagosomes and up-regulated the expressions of beclin 1 and LC3-II/I both transiently and stably. The autophagy inhibitor 3MA ameliorated the increase of cell diameter, volume, and protein content that were induced by apelin-13. These results suggested that apelin-13 promotes H9c2 rat cardiomyocyte hypertrophy via PI3K-Akt-ERK1/2-p70S6K and PI3K-induced autophagy.

A static pressure sensitive receptor APJ promote H9c2 cardiomyocyte hypertrophy via PI3K-autophagy pathway

This study is designed to investigate whether APJ receptor acts as a sensor in static pressure-induced cardiomyocyte hypertrophy and to investigate the mechanism of PI3K-autophagy pathway. The left ventricular hypertrophy rat model was established by coarctation of abdominal aorta. H9c2 rat cardiomyocytes were cultured in the presence of static pressure which was given by a custom-made pressure incubator. The results revealed that the expression of apelin/APJ system, PI3K, Akt and their phosphorylation were significantly increased in the operation group. Static pressure up-regulated the APJ expression, PI3K phosphorylation, Akt phosphorylation, LC3-II/I and beclin-1 expression in cardiomyocytes. APJ shRNA pGPU6/Neo-rat-399, PI3K inhibitor LY294002, Akt inhibitor 1701-1 blocked the up-regulation of APJ, PI3K phosphorylation, Akt phosphorylation, LC3-II/I and beclin-1 expression, respectively. Moreover, static pressure increased the diameter, volume, protein content of cells, and these could be reversed when the cells were treated with pGPU6/Neo-rat-399, LY294002, and autophagy inhibitor 3-methyladenine, respectively. These results suggested that static pressure up-regulates APJ expression to promote cardiomyocyte hypertrophy by a PI3K-autophagy pathway.

Cholesterol induces cardiac hypertrophy by activating the AKT pathway

Cardiac hypertrophy leads to decompensated heart function, predisposition to heart failure, and sudden death due to physiological and pathological stimuli. Although high cholesterol is considered a principal risk factor for atherosclerosis and heart disease, it has not been shown whether cholesterol itself is sufficient to cause cardiac hypertrophy. In this study, we investigated whether cholesterol induces cardiac hypertrophy, and identified cellular mechanisms underlying hypertrophic responses using H9c2 cells as a model system. Here we show that cholesterol loading significantly increased the cellular surface area and upregulated hypertrophy marker gene, β-myosin-heavy chain (β-MHC). Cholesterol loading alone activated the extracellular signal-regulated kinase (ERK)/mitogen activated protein kinase (MAPK) and phosphatidylinositol-3-kinase (PI3K)/AKT pathways. Conversely, cholesterol induced hypertrophic characteristic features such as increase in cellular surface area, and the expression of β-MHC mRNA is markedly inhibited by LY294002, a PI3K kinase inhibitor. These results suggest that cholesterol may play a key role in the development of cardiac hypertrophy through the activation of the PI3K/AKT pathway activation.

[Congestive heart failure: reverse cardiac remodeling mediated by left ventricular assist devices]

Left ventricular assist devices (LVAD) are currently used to treat patients with terminal congestive heart failure as a bridge to transplantation or as destination therapy in individuals with contraindications for cardiac transplantation. The LVADs are pulsatile or non-pulsatile systems that transport blood from the left ventricle to the ascending aorta parallel to the circulation thus providing a profound volume and pressure reduction in the left ventricle. The use of LVADs is associated with a considerable decrease of cardiac hypertrophy and dilation with significantly improved cardiac performance in a small subset of patients. The underlying process is termed reverse cardiac remodelling and is characterized by a significant decrease in the size of cardiomyocytes and reversible regulation of numerous molecular systems in the myocardium.

Morphological and molecular changes of the myocardium after left ventricular mechanical support

Left ventricular assist devices (LVAD) are currently used to either “bridge” patients with terminal congestive heart failure (CHF) until cardiac transplantation is possible or optionally for patients with contraindications for transplantation (“destination therapy”). Mechanical support is associated with a marked decrease of cardiac dilation and hypertrophy as well as numerous cellular and molecular changes (“reverse cardiac remodeling”), which can be accompanied by improved cardiac function (“bridge to recovery”) in a relatively small subset of patients with heart transplantation no longer necessary even after removal of the device (“weaning”). In the recent past, novel pharmacological strategies have been developed and are combined with mechanical support, which has increased the percentage of patients with improved clinical status and cardiac performance. Gene expression profiles have demonstrated that individuals who recover after LVAD show different gene expression compared to individuals who do not respond to unloading. This methodology holds promise for the future to develop read out frames to identify individuals who can recover after support. Aside from describing the morphological changes associated with “reverse cardiac remodeling”, this review will focus on signal transduction, transcriptional regulation, apoptosis, cell stress proteins, matrix remodeling, inflammatory mediators and aspects of neurohormonal activation in the failing human heart before and after ventricular unloading.