β-adrenergic receptor subtype signaling in the heart: from bench to the bedside

Associations between Selected ADRB1 and CYP2D6 Gene Polymorphisms in Children with Ventricular and Supraventricular Arrhythmias

Background and Objectives: Tachycardia is a common cardiovascular disease. Drugs blocking β1-adrenergic receptors (ADRB1) are used in the therapy of arrhythmogenic heart diseases. Disease-related polymorphisms can be observed within the ADRB1 gene. The two most important are Ser49Gly and Arg389Gly, and they influence the treatment efficacy. The family of the cytochrome P450 system consists of the isoenzyme CYP2D6 (Debrisoquine 4-hydroxylase), which is involved in phase I metabolism of almost 25% of clinically important drugs, including antiarrhythmic drugs. A study was conducted to detect the ADRB1 and CYP2D6 gene polymorphisms. Materials and Methods: The material for the test was whole blood from 30 patients with ventricular and supraventricular tachycardia and 20 controls. The samples were obtained from the Department of Pediatric Cardiology. The first to be made was the extraction of DNA using a GeneMATRIX Quick Blood DNA Purification Kit from EURx. The selected ADRB1 and CYP2D6 gene polymorphisms were detected by high-resolution melting polymerase chain reaction (HRM-PCR) analysis. Results: Based on the analysis of melt profile data for each PCR product, the identification of polymorphisms was carried out. Heterozygotes and homozygotes were found in the examined alleles. Conclusions: The frequency of the Arg389Gly polymorphism differs statistically significantly between the control group and patients with supraventricular and ventricular arrhythmias, as well as between these two groups of patients. Moreover, the Arg389Gly polymorphism was statistically more prevalent in the group of girls with SVT arrhythmia compared to girls with VT. A few carriers of homozygous and heterozygous systems of the S49G polymorphism were detected among patients with arrhythmias, as well as control group. The percentage of individuals carrying the CYP2D6 4 allele as either homozygous or heterozygous was observed in the study and control groups. The high prevalence of the CYP2D6*4 allele carriers in both groups prompts the optimization of beta-1 blocker therapy.

Regulatory mucosa-associated invariant T cells controlled by β1 adrenergic receptor signaling contribute to hepatocellular carcinoma progression

BACKGROUND AND AIMS

The innate-like mucosa-associated invariant T (MAIT) cells are enriched in human liver and have been linked to human HCC. However, their contributions to the progression of HCC are controversial due to the heterogeneity of MAIT cells, and new MAIT cell subsets remain to be explored.

APPROACH AND RESULTS

Combining single cell RNA sequencing (scRNA-seq) and flow cytometry analysis, we performed phenotypic and functional studies and found that FOXP3 + CXCR3 + MAIT cells in HCC patients were regulatory MAIT cells (MAITregs) with high immunosuppressive potential. These MAITregs were induced under Treg-inducing condition and predominantly from FOXP3 - CXCR3 + MAIT cells, which displayed mild Treg-related features and represented a pre-MAITreg reservoir. In addition, the induction and function of MAITregs were promoted by β1 adrenergic receptor signaling in pre-MAITregs and MAITregs, respectively. In HCC patients, high proportion of the intratumoral MAITregs inhibited antitumor immune responses and was associated with poor clinical outcomes.

CONCLUSIONS

Together, we reveal an immunosuppressive subset of MAIT cells in HCC patients that contributes to HCC progression, and propose a control through neuroimmune crosstalk.

Role of G-Proteins and GPCRs in Cardiovascular Pathologies

Cell signaling is a fundamental process that enables cells to survive under various ecological and environmental contexts and imparts tolerance towards stressful conditions. The basic machinery for cell signaling includes a receptor molecule that senses and receives the signal. The primary form of the signal might be a hormone, light, an antigen, an odorant, a neurotransmitter, etc. Similarly, heterotrimeric G-proteins principally provide communication from the plasma membrane G-protein-coupled receptors (GPCRs) to the inner compartments of the cells to control various biochemical activities. G-protein-coupled signaling regulates different physiological functions in the targeted cell types. This review article discusses G-proteins' signaling and regulation functions and their physiological relevance. In addition, we also elaborate on the role of G-proteins in several cardiovascular diseases, such as myocardial ischemia, hypertension, atherosclerosis, restenosis, stroke, and peripheral artery disease.

Palmitoylation and G-protein coupled receptors

More and more it is being appreciated that not all GPCRs are the same, sub-populations of GPCRs exist within a cell and function differently than others. The question is, how does one regulate a given sub-population? One way is through the addition of post-translational modifications to G-protein coupled receptors (GPCR). This process has long been known to occur and play a role in trafficking, pharmacology and ultimately function. This chapter will focus on one particular modification, that of S-palmitoylation, and its impact on GPCR function. We will discuss the history of this modification on these receptors and the connection with disease. We will highlight several examples from the literature of where palmitoylation impacts GPCR function.

Expression of the β1-adrenergic receptor (ADRB1) gene in the myocardium and β-adrenergic reactivity of the body in patients with a history of myocardium infraction

β1-adrenergic receptors (β1-AR) directly affect on intracardiac hemodynamic and the ability of the heart to tolerate physical activity by regulating its inotropic and chronotropic functions. Severe hypersympathicotonia, specific to coronary artery disease (CAD) and chronic heart failure (HF), leads to impaired functioning of β1-AR. The aim of this research was to assess the expression level of the β1-AR ADRB1 gene in the myocardium, to evaluate the β-adrenergic reactivity of the membrane (β-ARM) of erythrocytes, and to analyze the association of these parameters with myocardial contractile dysfunction in patients with a myocardial infarction (MI) in the past and without it. The study included 126 patients with chronic CAD. Among the patients, 55.6 % had a history of MI at least 6 months ago. The expression of the ADRB1 gene was assessed using real-time polymerase chain reaction. With this purpose, we isolated RNA from the right atrial appendage, which was excised when a heart-lung machine was connected during a planned coronary bypass surgery. β-ARM was evaluated in 57 patients. This method is based on the fact of inhibition of hemolysis of erythrocytes, placed in a hyposmotic medium, in the presence of a β-blocker. Within the whole sample of patients, the expression of the ADRB1 gene is comparable in different functional classes of HF. There was no linear correlation between the expression of the ADRB1 gene and left ventricle ejection fraction (LVEF). In patients with a history of MI, the expression of the ADRB1 gene was elevated when compared to a group of patients without MI (p = 0.017). Patients with a history of MI had higher values of β-ARM than those without MI (p = 0.017). The reverse correlation between β-ARM and LVEF (r = -0,570, p = 0,002) was revealed in the group of patients without MI but not in the group of patients with a history of MI (r = -0,137, p = 0,479). In the sample of patients with chronic CAD, in the myocardium of subjects with a history of MI, the relative expression of ADRB1 gene was higher compared to the group of patients without MI. In patients with different functional classes (FC) of HF and with different ejection fraction, both with MI and without it, ADRB1 gene expression was comparable. In the group of patients with a history of MI, an increase in β-ARM was observed, i.e. decrease in the number or sensitivity of β-AR. Among patients without MI, an inverse correlation was found between β-ARM and LVEF.

G-Protein-Coupled Receptors in Heart Disease

GPCRs (G-protein [guanine nucleotide-binding protein]-coupled receptors) play a central physiological role in the regulation of cardiac function in both health and disease and thus represent one of the largest class of surface receptors targeted by drugs. Several antagonists of GPCRs, such as βARs (β-adrenergic receptors) and Ang II (angiotensin II) receptors, are now considered standard of therapy for a wide range of cardiovascular disease, such as hypertension, coronary artery disease, and heart failure. Although the mechanism of action for GPCRs was thought to be largely worked out in the 80s and 90s, recent discoveries have brought to the fore new and previously unappreciated mechanisms for GPCR activation and subsequent downstream signaling. In this review, we focus on GPCRs most relevant to the cardiovascular system and discuss traditional components of GPCR signaling and highlight evolving concepts in the field, such as ligand bias, β-arrestin-mediated signaling, and conformational heterogeneity.

New Insights in Cardiac β-Adrenergic Signaling During Heart Failure and Aging

Heart failure (HF) has become increasingly common within the elderly population, decreasing their survival and overall quality of life. In fact, despite the improvements in treatment, many elderly people suffer from cardiac dysfunction (HF, valvular diseases, arrhythmias or hypertension-induced cardiac hypertrophy) that are much more common in an older fragile heart. Since β-adrenergic receptor (β-AR) signaling is abnormal in failing as well as aged hearts, this pathway is an effective diagnostic and therapeutic target. Both HF and aging are characterized by activation/hyperactivity of various neurohormonal pathways, the most important of which is the sympathetic nervous system (SNS). SNS hyperactivity is initially a compensatory mechanism to stimulate contractility and maintain cardiac output. Unfortunately, this chronic stimulation becomes detrimental and causes decreased cardiac function as well as reduced inotropic reserve due to a decrease in cardiac β-ARs responsiveness. Therapies which (e.g., β-blockers and physical activity) restore β-ARs responsiveness can ameliorate cardiac performance and outcomes during HF, particularly in older patients. In this review, we will discuss physiological β-adrenergic signaling and its alterations in both HF and aging as well as the potential clinical application of targeting β-adrenergic signaling in these disease processes.

New Insights in Cardiac β-Adrenergic Signaling During Heart Failure and Aging

Heart failure (HF) has become increasingly common within the elderly population, decreasing their survival and overall quality of life. In fact, despite the improvements in treatment, many elderly people suffer from cardiac dysfunction (HF, valvular diseases, arrhythmias or hypertension-induced cardiac hypertrophy) that are much more common in an older fragile heart. Since β-adrenergic receptor (β-AR) signaling is abnormal in failing as well as aged hearts, this pathway is an effective diagnostic and therapeutic target. Both HF and aging are characterized by activation/hyperactivity of various neurohormonal pathways, the most important of which is the sympathetic nervous system (SNS). SNS hyperactivity is initially a compensatory mechanism to stimulate contractility and maintain cardiac output. Unfortunately, this chronic stimulation becomes detrimental and causes decreased cardiac function as well as reduced inotropic reserve due to a decrease in cardiac β-ARs responsiveness. Therapies which (e.g., β-blockers and physical activity) restore β-ARs responsiveness can ameliorate cardiac performance and outcomes during HF, particularly in older patients. In this review, we will discuss physiological β-adrenergic signaling and its alterations in both HF and aging as well as the potential clinical application of targeting β-adrenergic signaling in these disease processes.

Danhong injection attenuates isoproterenol-induced cardiac hypertrophy by regulating p38 and NF-κb pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Danhong injection (DHI), derived from Rhizoma Salviae Miltiorrhizae (Salvia miltiorrhiza Bge., Labiatae, Danshen in Chinese) and Flos Carthami (Carthamus tinctorius L., Compositae, Salvia militiorrhiza Bunge), is an extensively-used Chinese material standardized clinical product for treatment of cardiovascular diseases.

AIM OF THE STUDY

Cardiac hypertrophy (CH) is an adaptive response of cardiomyocytes. Long-lasting cardiac hypertrophy results in the loss of compensation by cardiomyocytes which could ultimately develop into heart failure. In the present study, we aimed to investigate the effect and exact mechanisms of DHI on isoproterenol (ISO)-induced CH.

MATERIALS AND METHODS

H9c2 cells and male Wistar rats were stimulated by ISO in the present study to establish CH models in vitro and in vivo. CCk-8 assay, Western blot, real time-polymerase chain reaction (RT-PCR), electrophoretic mobility shift assay (EMSA) and Echocardiography were used in the present study.

RESULTS

DHI significantly attenuated ISO-induced CH of H9c2 cells (p<0.01). DHI decreased ISO-induced atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) elevation both at the mRNA and protein levels (p<0.05 and p<0.01, respectively). Western blot showed that DHI down-regulated the phosphorylation of p38. Furthermore, we found that DHI inhibited the nuclear translocation and activation of NF-κb. Echocardiography from ISO-induced CH rats showed that DHI significantly decreased left ventricle (LV) mass, the thickness of the LV end-systolic posterior wall (LVPWs), and the LV end-diastolic posterior wall (LVPWd) elevated by ISO (p<0.01 and p<0.05, respectively).

CONCLUSION

These data demonstrate that DHI might exert anti-cardiac hypertrophic effects by regulating p38 and NF-κb pathway.