E2A ablation enhances proportion of nodal-like cardiomyocytes in cardiac-specific differentiation of human embryonic stem cells

Differentiation of Sinoatrial-like Cardiomyocytes as a Biological Pacemaker Model

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are widely used for disease modeling and pharmacological screening. However, their application has mainly focused on inherited cardiopathies affecting ventricular cardiomyocytes, leading to extensive knowledge on generating ventricular-like hiPSC-CMs. Electronic pacemakers, despite their utility, have significant disadvantages, including lack of hormonal responsiveness, infection risk, limited battery life, and inability to adapt to changes in heart size. Therefore, developing an in vitro multiscale model of the human sinoatrial node (SAN) pacemaker using hiPSC-CM and SAN-like cardiomyocyte differentiation protocols is essential. This would enhance the understanding of SAN-related pathologies and support targeted therapies. Generating SAN-like cardiomyocytes offers the potential for biological pacemakers and specialized conduction tissues, promising significant benefits for patients with conduction system defects. This review focuses on arrythmias related to pacemaker dysfunction, examining protocols' advantages and drawbacks for generating SAN-like cardiomyocytes from hESCs/hiPSCs, and discussing therapeutic approaches involving their engraftment in animal models.

Cadherin-5 facilitated the differentiation of human induced pluripotent stem cells into sinoatrial node-like pacemaker cells by regulating β-catenin

Our study was conducted to investigate whether cadherin-5 (CDH5), a vascular endothelial cell adhesion glycoprotein, could facilitate the differentiation of human induced pluripotent stem cells (hiPSCs) into sinoatrial node-like pacemaker cells (SANLPCs), following previous findings of silk-fibroin hydrogel-induced direct conversion of quiescent cardiomyocytes into pacemaker cells in rats through the activation of CDH5. In this study, the differentiating hiPSCs were treated with CDH5 (40 ng/mL) between Day 5 and 7 during cardiomyocytes differentiation. The findings in the present study demonstrated that CDH5 stimulated the expression of pacemaker-specific markers while suppressing markers associated with working cardiomyocytes, resulting in an increased proportion of SANLPCs among hiPSCs-derived cardiomyocytes (hiPSC-CMs) population. Moreover, CDH5 induced typical electrophysiological characteristics resembling cardiac pacemaker cells in hiPSC-CMs. Further mechanistic investigations revealed that the enriched differentiation of hiPSCs into SANLPCs induced by CDH5 was partially reversed by iCRT14, an inhibitor of β-catenin. Therefore, based on the aforementioned findings, it could be inferred that the regulation of β-catenin by CDH5 played a crucial role in promoting the enriched differentiation of hiPSCs into SANLPCs, which presents a novel avenue for the construction of biological pacemakers in forthcoming research.

Protocatechuic Aldehyde Alleviates d -Galactose-Induced Cardiomyocyte Senescence by Regulating the TCF3/ATG5 Axis

ABSTRACT

Cardiomyocyte senescence is an independent risk factor for cardiovascular diseases. Protocatechuic aldehyde (PCA) is a natural chemical in the Chinese medicinal herb Salvia miltiorrhiza . PCA could protect against oxidative stress and inflammation in the cardiovascular system. In present study, we treated H9C2 cells with d -galactose to establish an in vitro model of cardiomyocyte senescence and investigated the role and underlying mechanisms of PCA in myocardial cell senescence. It was found that d -galactose induced transcription factor 3 (TCF3) expression and decreased autophagy-related genes 5 (ATG5) expression. Meanwhile, inflammation and senescence were exacerbated by d -galactose. TCF3 transcriptionally inhibited ATG5 expression. TCF3 knockdown abolished the effects of d -galactose on H9C2 by activating ATG5-mediated autophagy. PCA hindered TCF3 and inflammation to alleviate the d -galactose-induced senescence of H9C2 cells in a dose-dependent manner. Whereas, the anti-inflammation and anti-senescence effects of PCA were reversed by TCF3 knockdown. Furthermore, absence of ATG5 partially eliminated the impacts of PCA on H9C2 cells treated with d -galactose. Conclusively, PCA alleviated d -galactose-induced senescence by downregulating TCF3, promoting ATG5-mediated autophagy, and inhibiting inflammation in H9C2 cells. These results elucidated the potential mechanism by which PCA alleviated cardiomyocyte senescence and enabled its application in treating cardiomyocyte senescence.

Human-Induced Pluripotent Stem Cell-Based Differentiation of Cardiomyocyte Subtypes for Drug Discovery and Cell Therapy

Drug attrition rates have increased over the past few years, accompanied with growing costs for the pharmaceutical industry and consumers. Lack of in vitro models connecting the results of toxicity screening assays with clinical outcomes accounts for this high attrition rate. The emergence of cardiomyocytes derived from human pluripotent stem cells provides an amenable source of cells for disease modeling, drug discovery, and cardiotoxicity screening. Functionally similar to to embryonic stem cells, but with fewer ethical concerns, induced pluripotent stem cells (iPSCs) can recapitulate patient-specific genetic backgrounds, which would be a huge revolution for personalized medicine. The generated iPSC-derived cardiomyocytes (iPSC-CMs) represent different subtypes including ventricular-, atrial-, and nodal-like cardiomyocytes. Purifying these subtypes for chamber-specific drug screening presents opportunities and challenges. In this chapter, we discuss the strategies for the purification of iPSC-CMs, the use of iPSC-CMs for drug discovery and cardiotoxicity test, and the current limitations of iPSC-CMs that should be overcome for wider and more precise cardiovascular applications.

Cardiac stem cells: Current knowledge and future prospects

Regenerative medicine is the field concerned with the repair and restoration of the integrity of damaged human tissues as well as whole organs. Since the inception of the field several decades ago, regenerative medicine therapies, namely stem cells, have received significant attention in preclinical studies and clinical trials. Apart from their known potential for differentiation into the various body cells, stem cells enhance the organ's intrinsic regenerative capacity by altering its environment, whether by exogenous injection or introducing their products that modulate endogenous stem cell function and fate for the sake of regeneration. Recently, research in cardiology has highlighted the evidence for the existence of cardiac stem and progenitor cells (CSCs/CPCs). The global burden of cardiovascular diseases’ morbidity and mortality has demanded an in-depth understanding of the biology of CSCs/CPCs aiming at improving the outcome for an innovative therapeutic strategy. This review will discuss the nature of each of the CSCs/CPCs, their environment, their interplay with other cells, and their metabolism. In addition, important issues are tackled concerning the potency of CSCs/CPCs in relation to their secretome for mediating the ability to influence other cells. Moreover, the review will throw the light on the clinical trials and the preclinical studies using CSCs/CPCs and combined therapy for cardiac regeneration. Finally, the novel role of nanotechnology in cardiac regeneration will be explored.

Cardiac stem cells: Current knowledge and future prospects

Regenerative medicine is the field concerned with the repair and restoration of the integrity of damaged human tissues as well as whole organs. Since the inception of the field several decades ago, regenerative medicine therapies, namely stem cells, have received significant attention in preclinical studies and clinical trials. Apart from their known potential for differentiation into the various body cells, stem cells enhance the organ's intrinsic regenerative capacity by altering its environment, whether by exogenous injection or introducing their products that modulate endogenous stem cell function and fate for the sake of regeneration. Recently, research in cardiology has highlighted the evidence for the existence of cardiac stem and progenitor cells (CSCs/CPCs). The global burden of cardiovascular diseases' morbidity and mortality has demanded an in-depth understanding of the biology of CSCs/CPCs aiming at improving the outcome for an innovative therapeutic strategy. This review will discuss the nature of each of the CSCs/CPCs, their environment, their interplay with other cells, and their metabolism. In addition, important issues are tackled concerning the potency of CSCs/CPCs in relation to their secretome for mediating the ability to influence other cells. Moreover, the review will throw the light on the clinical trials and the preclinical studies using CSCs/CPCs and combined therapy for cardiac regeneration. Finally, the novel role of nanotechnology in cardiac regeneration will be explored.