Purpose Of Review: The sinoatrial node (SAN), the natural pacemaker of the heart, is responsible for generating electrical impulses and initiating each heartbeat. Sinoatrial node dysfunction (SND) causes various arrhythmias such as sinus arrest, SAN block, and tachycardia/bradycardia syndrome. Unraveling the underlying mechanisms of SND is of paramount importance in the pursuit of developing effective therapeutic strategies for patients with SND. This review provides a concise summary of the most recent progress in the signaling regulation of SND.
Recent Findings: Recent studies indicate that SND can be caused by abnormal intercellular and intracellular signaling, various forms of heart failure (HF), and diabetes. These discoveries provide novel insights into the underlying mechanisms SND, advancing our understanding of its pathogenesis. SND can cause severe cardiac arrhythmias associated with syncope and an increased risk of sudden death. In addition to ion channels, the SAN is susceptible to the influence of various signalings including Hippo, AMP-activated protein kinase (AMPK), mechanical force, and natriuretic peptide receptors. New cellular and molecular mechanisms related to SND are also deciphered in systemic diseases such as HF and diabetes. Progress in these studies contributes to the development of potential therapeutics for SND.
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http://dx.doi.org/10.1007/s11886-023-01885-8 | DOI Listing |
Cells
December 2024
Laboratory of Cardiovascular Science, Intramural Research Program, National Institute on Aging, National Institute of Health, Baltimore, MD 21224, USA.
The spontaneous firing of the sinoatrial (SA) node, the physiological pacemaker of the heart, is generated within sinoatrial nodal cells (SANCs) and is regulated by a "coupled-clock" pacemaker system, which integrates a "membrane clock", the ensemble of ion channel currents, and an intracellular "Ca clock", sarcoplasmic reticulum-generated local submembrane Ca releases via ryanodine receptors. The interactions within a "coupled-clock" system are modulated by phosphorylation of surface membrane and sarcoplasmic reticulum proteins. Though the essential role of a high basal cAMP level and PKA-dependent phosphorylation for basal spontaneous SANC firing is well recognized, the role of basal CaMKII-dependent phosphorylation remains uncertain.
View Article and Find Full Text PDFCells
December 2024
Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan.
Induced pluripotent stem cell (iPSC)-derived biological pacemakers have emerged as an alternative to traditional electronic pacemakers for managing cardiac arrhythmias. While effective, electronic pacemakers face challenges such as device failure, lead complications, and surgical risks, particularly in children. iPSC-derived pacemakers offer a promising solution by mimicking the sinoatrial node's natural pacemaking function, providing a more physiological approach to rhythm control.
View Article and Find Full Text PDFCell Rep
December 2024
Precision Cardiology Laboratory, The Broad Institute, Cambridge, MA 02142, USA; Cardiovascular Research Center, Massachusetts General Hospital, Boston, MA 02114, USA; Cardiology Division, Massachusetts General Hospital, Boston, MA 02114, USA. Electronic address:
We sought to characterize cellular composition across the cardiovascular system of the healthy Wistar rat, an important model in preclinical cardiovascular research. We performed single-nucleus RNA sequencing (snRNA-seq) in 78 samples in 10 distinct regions, including the four chambers of the heart, ventricular septum, sinoatrial node, atrioventricular node, aorta, pulmonary artery, and pulmonary veins, which produced 505,835 nuclei. We identified 26 distinct cell types and additional subtypes, with different cellular composition across cardiac regions and tissue-specific transcription for each cell type.
View Article and Find Full Text PDFFront Med (Lausanne)
December 2024
Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom.
Background: The sinoatrial node (SN) generates the heart rate (HR). Its spontaneous activity is regulated by a complex interplay between the modulation by the autonomic nervous system (ANS) and intrinsic factors including ion channels in SN cells. However, the systemic and intrinsic regulatory mechanisms are still poorly understood.
View Article and Find Full Text PDFCardiovasc Drugs Ther
December 2024
Cardiovascular Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Background: Ivabradine has been identified as a funny current (If) inhibitor in the sinoatrial node (SAN) and is considered an advocated therapeutic agent in chronic heart failure and stable angina. This therapeutic agent has shown positive benefits in maintaining a reduction in heart rate while sustaining hemodynamic stability. Its clinical application is still evolving and the mechanism of action is becoming clearer daily.
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