Calcium is crucial in governing contractile activities of myofilaments in cardiomyocytes, any defeats in calcium homeostasis of the cells would adversely affect heart pumping action. The characterization of calcium handling properties in human induced pluripotent stem cell-derived cardiomyocytes (iPS-CMCs) is of significant interest and pertinent to the stem cell and cardiac regenerative field because of their potential patient-specific therapeutic use.

Defined as, “The science about the development of an embryo from the fertilization of the ovum to the fetus stage,” embryology has been a mainstay at universities throughout the world for many years. Throughout the last century, embryology became overshadowed by experimental-based genetics and cell biology, transforming the field into developmental biology, which replaced embryology in Biology departments in many universities. Major contributions in this young century in the fields of molecular biology, biochemistry and genomics were integrated with both embryology and developmental biology to provide an understanding of the molecular portrait of a “development cell.” That new integrated approach is known as stem-cell biology; it is an understanding of the embryology and development together at the molecular level using engineering, imaging and cell culture principles, and it is at the heart of this seminal book. Stem Cells and Regenerative Medicine: From Molecular Embryology to Tissue Engineering is completely devoted to the basic developmental, cellular and molecular biological aspects of stem cells as well as their clinical applications in tissue engineering and regenerative medicine. It focuses on the basic biology of embryonic and cancer cells plus their key involvement in self-renewal, muscle repair, epigenetic processes, and therapeutic applications. In addition, it covers other key relevant topics such as nuclear reprogramming induced pluripotency and stem cell culture techniques using novel biomaterials. A thorough introduction to stem-cell biology, this reference is aimed at graduate students, post-docs, and professors as well as executives and scientists in biotech and pharmaceutical companies.

This dissertation, "Calcium Signaling in Human Pluripotent Stem Cell-derived Ventricular Cardiomyocytes" by Sen, Li, 李森, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Human pluripotent stem cells (hPSCs) serve as a potential unlimited ex vivo source of cardiomyocytes (CMs) for disease modeling, cardiotoxicity screening, drug discovery and cell‐based therapies. However, as shown in previous studies conducted by our lab (Poon, Kong et al. 2011), human embryonic stem cells (hESCs)‐derived CMs display immature〖Ca〗 DEGREES(2+)-handing properties with smaller transient amplitudes, slower rise and decay kinetics than those of adult CMs. Although the cytosolic 〖Ca〗 DEGREES(2+) signaling of hESC‐CMs has only recently been understood, there is no investigation on the nuclear 〖Ca〗 DEGREES(2+) signal in hESC‐CMs, despite its importance. In this dissertation, delayed kinetics of nuclear 〖Ca〗 DEGREES(2+), as compared to that of cytosol during 〖Ca〗 DEGREES(2+)waves or 〖Ca〗 DEGREES(2+) transients, was found in hESC‐derived ventricular (V) CMs, indicating that nuclear 〖Ca〗 DEGREES(2+) was initiated by 〖Ca〗 DEGREES(2+) diffusion from cytosol. Besides global 〖Ca〗 DEGREES(2+) signals, local nuclear 〖Ca〗 DEGREES(2+) signals were observed and identified as Ca2+ release from ryanodine receptors (RyRs), and nucleoplasmic reticulum (NR) served as their structural basis. In addition, targeted expression of 〖Ca〗 DEGREES(2+) buffering protein parvalbumin (PV) in cytosol or nucleus altered 〖Ca〗 DEGREES(2+) transient and stimuli‐induced apoptosis of hESC‐VCMs. For cytosolic 〖Ca〗 DEGREES(2+) signaling in hESC‐VCMs, the mechanistic basis of excitation‐contraction coupling of hESC‐VCMs was studied by using 〖Ca〗 DEGREES(2+) sparks, which are the unitary 〖Ca〗 DEGREES(2+) ‐events. The results indicated that RyRs could be sensitized by 〖Ca〗 DEGREES(2+) in permeabilized hESC‐VCMs. Increasing external 〖Ca〗 DEGREES(2+) dramatically escalated the basal 〖Ca〗 DEGREES(2+) and spark frequency. Furthermore, RyR‐mediated Ca2+ release sensitized nearby RyRs, leading to compound 〖Ca〗 DEGREES(2+) sparks, whereas inhibition of mitochondrial 〖Ca〗 DEGREES(2+) + uptake promoted Ca2+ waves. The aforementioned immature 〖Ca〗 DEGREES(2+)-handing properties of hESC‐CMs can be attributed to their differential expression of crucial Ca2+-handling proteins. During diastole, SERCA and NCX sequester and extrude 〖Ca〗 DEGREES(2+) ions, respectively, to return cytosolic 〖Ca〗 DEGREES(2+) to the resting level. As previously published in our lab, NCX, robustly expressed in hESC‐CMs but much less so in the adult counterparts, is a functional determinant of immature 〖Ca〗 DEGREES(2+) homeostasis. Unlike NCX, SERCA is expressed less in hESC‐CMs than in adult‐CMs. The present study first demonstrated the effects of lentivirus‐based genetic manipulation of SERCA2a and NCX1 in hESC‐VCMs, and the results indicated that SERCA2a overexpression shortened the decay phase of low‐frequency (0.5 Hz) electrical stimulation‐elicited Ca2+ transient. Increasing pacing frequency from 0.5 Hz to 2 Hz led to a decrease of relative transient amplitude, showing that hESC‐VCMs harbored a negative‐frequency response. At a high‐stimulation frequency of 2 Hz, it was revealed that SERCA overexpression, but not NCX1 suppression, increased the amplitude of 〖Ca〗 DEGREES(2+) transient by accelerating 〖Ca〗 DEGREES(2+) sequestration to sarcoplasmic reticulum (SR), indicating partial rescue of the negative‐frequency response. T

Under normal, healthy conditions, the contraction of cardiac myocytes, leading to the pump function of this organ, is driven by calcium-dependent mechanisms. Entry of calcium into the myocyte during the cardiac action potential causes activation of the ryanodine receptors and release of calcium from the sarcoplasmic reticulum. This process termed calcium-induced calcium release is essential for excitation-contraction coupling and enables each action potential to be transduced into a mechanical event. Indeed, in healthy myocytes, the calcium concentration in the cytosol of is elevated approximately 10-fold from a resting level of ∼100 nM to ∼1 μM. This process is finely orchestrated by a number of key proteins, which can be specifically regulated by various pathways depending on the oxygen demand. Furthermore, the specific structure of the myocyte allows certain calcium-dependent processes to be compartmentalised, increasing the efficiency and safety of this regulation. Heart failure is a common, costly, and life-threatening condition. In 2015, for example, it affected around 40 million people globally. In patients with heart failure, the risk of sudden cardiac death and arrhythmias increases substantially. Cellular remodelling and alterations in calcium handling, which appear to contribute to the arrhythmogenic burden in heart failure, have been extensively reported. However, a number of unanswered questions remain, and each new study - while continuing to shed light on this subject - raises additional novel questions. This current compendium of articles covers a number of aspects and comprehensively reviews current knowledge and perspectives regarding the link between calcium handling, arrhythmias and heart failure providing at the same time insights that may lead to novel therapeutic options for the future.

This volume provides methodologies for ES and iPS cell technology on the study of cardiovascular diseases. Chapters guide readers through protocols on cardiomyocyte generation from pluripotent stem cells, physiological measurements, bioinformatic analysis, gene editing technology, and cell transplantation studies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and cutting-edge, Pluripotent Stem-Cell Derived Cardiomyocytes aims to help researchers set up experiments using pluripotent stem cell-derived cardiac cells.

Cardiac Tissue Engineering: Methods and Protocols presents a collection of protocols on cardiac tissue engineering from pioneering and leading researchers around the globe. These include methods and protocols for cell preparation, biomaterial preparation, cell seeding, and cultivation in various systems. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and key tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Cardiac Tissue Engineering: Methods and Protocols highlights the major techniques, both experimental and computational, for the study of cardiovascular tissue engineering.