Heart failure, as a result of myocardial infarction, is a major cause of mortality in human. The main cause of heart failure is that when adult cardiomyocytes die in the infarct site they do not regenerate. Instead the infract site is replaced by fibroblasts and collagen scar. It is generally believed that cardiomyocytes have terminally differentiated and can not divide to replace cardiomyocytes that have lost following injury. However, recently published data have provided new evidence that there is a small but continuously turnover of cardiomyocytes in the adult heart. These new findings provide a new theory that the heart does possess a limited ability to regenerate. / I also examined the regenerative ability of cardiomyocyte in adult heart. MRL mice were used because previously it has been reported that the cardiomyocyte could proliferate in response to injury. To understand how the cardiomyocytes in the MRL mouse heart, I used a cryo-injury approach. I discovered that the cardiomyoctyes in MRL mouse hearts were capable of dividing shortly after cryo-injury. These MRL hearts healed without scarring in contrast to C57BL/6 control mice. It was discovered that BMP-2, GATA4 and Nkx2.5 were involved in the healing process. The activation of these genes induced the cardiomyocyte to re-enter the cell cycle so that new cardiomyocytes could replace the cell that have been lost in the infarct site. I also discovered that stem cells may also play a minor role in the healing process. / In summary, my research findings revealed that cardiomyocytes regeneration in the heart is a very complex process that involves the participation of many cells and signalling pathway. There findings raise many intriguing and important questions and are worthy of being addressed in the future. / Stem cell therapy has been proposed as a potential treatment for various myocardial diseases. Chen et al. (2004) found small chemical called reversine that could dedifferentiate C2C12 cells to become stem-like cells. In this study, I demonstrated that reversine could inhibit the growth of C2C12 cell. The presence of reversine in cell culture could significantly inhibit muscle-specific genes MyoD, Myogenin and Myf5 expression. These 3 muscle specific transcriptional genes are essential for maintaining muscle differentiation. The down regulation of these gene showed that reversine could dedifferentiate C2C12 cells. We also discovered that reversine-treated C2C12 cells could differentiate into cardiomyocytes when they were cocultured with cardiomyocytes or when transplanted into the infarct site of a cryo-injured heart. / To investigate the regenerative potential of cardiomyoctyes in adult heart, we tried first to uncover the signals that direct post-natal cardiomyocytes to enter into growth arrest and differentiation. In the first part of my study, I established that the cardiomycytes divided extensively in 2 day-old post-natal hearts and that the majority of these cells entered into growth arrest and terminal differentiation at day 13. Comparative proteomic techniques were used in order to identify proteins that might be associated with cardiomyocytes proliferation during terminal differentiation the mouse heart. Several proteins were found to be differently expressed and amongst them was cyclin I protein. Cyclin I was found strongly expressed in 13 day old hearts. The protein is involved in signaling growth arrested in cells. / Liu, Ye. / "November 2006." / Adviser: Lee Ka Ho. / Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 5658. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 142-172). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

Leung, Sze Lee Cecilia. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 144-153). / Abstracts in English and Chinese. / Abstract --- p.i / Abstract in Chinese (摘要） --- p.iii / Acknowledgements --- p.v / Table of Content --- p.vi / Abbreviations --- p.xv / Chapter CHAPTER 1 --- INTRODUCTION / Chapter 1.1 --- Stem cells --- p.1 / Chapter 1.1.1 --- Adult stem cells --- p.2 / Chapter 1.1.2 --- Embryonic stem cells --- p.2 / Chapter 1.1.3 --- Pros and cons of embryonic and adult stem cells --- p.5 / Chapter 1.1.4 --- Human embryonic stem cells (hESCs) --- p.6 / Chapter 1.1.5 --- Mouse embryonic stem cells (mESCs) --- p.7 / Chapter 1.1.6 --- Characteristics of ESC-derived cardiomyocytes --- p.7 / Chapter 1.2 --- Cardiovascular Diseases (CVD) --- p.9 / Chapter 1.2.1 --- Causes and statistics of CVD --- p.9 / Chapter 1.2.2 --- Current treatment for CVD --- p.10 / Chapter 1.2.3 --- Current hurdles of putting hESC-CMs into clinical use --- p.11 / Chapter 1.3 --- Myosin light chain2v --- p.13 / Chapter 1.4 --- Genetic-engineering of hESCs & their cardiac derivatives by lentiviral-mediate gene transfer --- p.14 / Chapter 1.5 --- Cytokines secretion during myocardial infarction --- p.15 / Chapter 1.6 --- Aims of the Project --- p.19 / Chapter 1.7 --- Significance of the Project --- p.19 / Chapter CHAPTER 2 --- MATERIALS AND METHODS / Chapter 2.1 --- Subcloning --- p.20 / Chapter 2.1.1 --- Amplification of MLC-2v --- p.20 / Chapter 2.1.2 --- Purification of DNA product --- p.21 / Chapter 2.1.3 --- Restriction enzyme digestion --- p.21 / Chapter 2.1.4 --- Ligation of MLC-2v promoter with DuetO 11 vector --- p.22 / Chapter 2.1.5 --- Transformation of ligation product into competent cells --- p.22 / Chapter 2.1.6 --- PCR confirmation of successful ligation --- p.23 / Chapter 2.1.7 --- Small-scale preparation of bacterial plasmid DNA --- p.23 / Chapter 2.1.8 --- Restriction enzyme digestions to reconfirm positive clones --- p.24 / Chapter 2.1.9 --- DNA sequencing of the cloned plasmid DNA --- p.25 / Chapter 2.1.10 --- Large-scale preparation of target recombinant expression vector --- p.25 / Chapter 2.2 --- Mouse Embryonic Fibroblast (MEF) Culture --- p.26 / Chapter 2.2.1 --- Derivation of MEF --- p.26 / Chapter 2.2.2 --- Mouse embryonic fibroblast cells culture --- p.27 / Chapter 2.2.3 --- Irradiation of mouse embryonic fibroblast --- p.28 / Chapter 2.3 --- HESC culture --- p.29 / Chapter 2.3.1 --- Thawing and Plating hESCs --- p.29 / Chapter 2.3.2 --- Splitting hESCs --- p.30 / Chapter 2.3.3 --- "Culture maintainence, selection and colony removal" --- p.31 / Chapter a) --- Distinguish differentiated and undifferentiated cells and colonies / Chapter b) --- "Remove differentiated cells by ""Picking to Remove""" / Chapter c) --- "Remove undifferentiated cells by ""Picking to Keep""" / Chapter 2.3.4 --- Freezing hESCs --- p.31 / Chapter 2.3.5 --- Differentiation of hESCs --- p.32 / Chapter 2.3.6 --- "HESC culture on feeder free system, mTeSR TM1" --- p.34 / Chapter a) --- Preparation of mTeSRTMl / Chapter b) --- Preparation of BD MatrigelTM hESC-qualified Matrix aliquots / Chapter c) --- Coating plates with BD MatrigelTM hESC-qualified Matrix / Chapter d) --- Human Embryonic stem cells culture in mTeSRTMl / Chapter 2.4 --- ES Cell Characterization (Chemicon Cat# SCR001) --- p.36 / Chapter 2.4.1 --- Alkaline Phosphatase Staining --- p.36 / Chapter 2.4.2 --- Immunofluorescence staining --- p.37 / Chapter 2.5 --- MESC culture --- p.38 / Chapter 2.5.1 --- Thawing and Plating mESCs --- p.38 / Chapter 2.5.2 --- Splitting mESCs --- p.38 / Chapter 2.5.3 --- Differentiation of mESCs --- p.39 / Chapter 2.5.4 --- To study the effects of cytokines on mESC differentiation --- p.40 / Chapter 2.6 --- Lentivirus (LV) Packaging --- p.41 / Chapter 2.6.1 --- Transfection of lentiviral vectors into HEK293FT cells --- p.41 / Chapter 2.6.2 --- LV titering --- p.42 / Chapter 2.7 --- MultipleTransduction --- p.43 / Chapter 2.8 --- Selection of transduced cells by hygromycin --- p.43 / Chapter 2.8.1 --- Determination of hygromycin selection dosage --- p.43 / Chapter 2.8.2 --- Selection of stable clones --- p.44 / Chapter 2.9 --- Isolation of green fluorescent cardiomyocytes derived from differentiated hESCs --- p.45 / Chapter 2.9.1 --- Collagenase digestion of embryoid bodies into single cells --- p.45 / Chapter 2.9.2 --- FACS --- p.46 / Chapter 2.10 --- Gene expression study / Chapter 2.10.1 --- Primer design --- p.46 / Chapter 2.10.2 --- RNA extraction --- p.46 / Chapter 2.10.3 --- DNase Treatment --- p.47 / Chapter 2.10.4 --- Synthesis of Double-stranded cDNA from Total RNA --- p.47 / Chapter 2.10.5 --- Quantitative real-time PCR --- p.48 / Chapter 2.10.6 --- Quantification of mRNA expression --- p.49 / Chapter 2.11 --- Protein Expression study --- p.49 / Chapter 2.11.1 --- Crude protein extraction --- p.49 / Chapter 2.11.2 --- Quantitation of protein samples --- p.50 / Chapter 2.11.3 --- SDS-PAGE --- p.50 / Chapter 2.11.4 --- Western Blot --- p.51 / Chapter 2.11.5 --- Western blot luminal detection --- p.52 / Chapter 2.11.6 --- Quantification of protein expression --- p.52 / Chapter CHAPTER 3 --- PURIFICATION OF CARDIOMYOCYTES DERIVED FROM DIFFERENTIATED HESCs / Chapter 3.1 --- Subcloning --- p.57 / Chapter 3.1.1 --- Linearization of DuetO11 and excision of UBC promoter --- p.58 / Chapter 3.1.2 --- PCR cloning of MLC-2V --- p.59 / Chapter 3.1.3 --- Ligation of MLC-2v promoter to linearized DuetO11 --- p.60 / Chapter 3.1.3.1 --- Colony PCR to screen for positive clones --- p.61 / Chapter 3.1.3.2 --- Restriction digestion to confirm the success of ligation --- p.61 / Chapter 3.2 --- Lentivirus (LV) packaging --- p.62 / Chapter 3.2.1 --- Transfection --- p.63 / Chapter 3.2.2 --- LV titering --- p.64 / Chapter 3.3 --- HESC culture --- p.66 / Chapter 3.4 --- Multi-transduction of hESCs with LVs --- p.67 / Chapter 3.5 --- Differentiation after transduction --- p.69 / Chapter 3.6 --- Antibiotic selection --- p.71 / Chapter 3.6.1 --- Characterization of hESCs on feeder free system --- p.72 / Chapter 3.6.1.1 --- Alkaline Phosphatase (AP) staining --- p.72 / Chapter 3.6.1.2 --- Immunostaining with pluripotency marker --- p.73 / Chapter 3.6.2 --- Determination of hygromycin dosage by MTT assay --- p.74 / Chapter 3.6.3 --- HESCs after selection in feeder free system --- p.75 / Chapter 3.7 --- Differentiation of hESCs after selection --- p.76 / Chapter 3.8 --- FACS --- p.77 / Chapter 3.9 --- QPCR of cells after FACS --- p.80 / Chapter 3.9.1 --- Gene expression of Nkx2.5 --- p.81 / Chapter 3.9.2 --- Gene expression of c-Tnl --- p.82 / Chapter 3.9.3 --- Gene expression of c-TnT --- p.83 / Chapter 3.9.3 --- Gene expression of MLC-2v --- p.84 / Chapter CHAPTER 4 --- THE STUDY OF CYTOKINES' EFFECT ON MESC DIFFERENTIATION / Chapter 4.1 --- mESC culture --- p.85 / Chapter 4.2 --- The effect of cytokines on the differentiation of mESCs --- p.86 / Chapter 4.2.1 --- Beating curves of mESCs treated with different concentrations of cytokines at differentiation day 2 to 6 before attachment --- p.88 / Chapter 4.2.2 --- qPCR to determine the cytokines' effect on the differentiation of mESCs --- p.94 / Chapter 4.2.2.1 --- The effect of IL-1α on the expression of cardiac specific genes --- p.95 / Chapter 4.2.2.2 --- The effect of IL-1β on the expression of cardiac specific genes --- p.98 / Chapter 4.2.2.3 --- The effect of IL-6 on the expression of cardiac specific genes --- p.101 / Chapter 4.2.2.4 --- The effect of IL-10 on the expression of cardiac specific genes --- p.104 / Chapter 4.2.2.5 --- The effect of IL-18 on the expression of cardiac specific genes --- p.107 / Chapter 4.2.2.6 --- The effect of TNF-α on the expression of cardiac specific genes --- p.110 / Chapter 4.2.3 --- Western blot analysis of the cytokines' effect on the differentiation of mESCs --- p.113 / Chapter 4.2.3.1 --- The effect of IL-lα on the abundance of cardiac specific proteins --- p.114 / Chapter 4.2.3.2 --- The effect of IL-1β on the abundance of cardiac specific proteins --- p.116 / Chapter 4.2.3.3 --- The effect of IL-6 on the abundance of cardiac specific proteins --- p.118 / Chapter 4.2.3.4 --- The effect of IL-10 on the abundance of cardiac specific proteins --- p.120 / Chapter 4.2.3.5 --- The effect of IL-18 on the abundance of cardiac specific proteins --- p.122 / Chapter 4.2.3.6 --- The effect of TNF-α on the abundance of cardiac specific proteins --- p.124 / Chapter CHAPTER 5 --- DISCUSSION / Chapter 5.1 --- Purification of cardiomyocytes derived from differentiated hESCs --- p.127 / Chapter 5.2 --- Study on the effect of cytokines on mESC differentiation --- p.135 / Chapter 5.3 --- Conclusion --- p.142 / REFERENCES --- p.144

Thesis (Ph.D.)--Virginia Commonwealth University, 2009. / Prepared for: Dept. of Physiology. Title from resource description page. Includes bibliographical references.

Cyclic guanosine 3', 5'-monophosphate (cGMP) has recently emerged as an endogenous regulator for controlling or reversing cardiac hypertrophy. Increased protein accumulation is a key feature of cardiac hypertrophy; thus, our study investigates the effects of a cGMP analog on protein accumulation in primary culture of adult rat cardiomyocytes and dissects out the mechanisms involved. We confirmed that a cGMP analog, 8-bromo-cGMP, inhibits phenylephrine (PE)-increased accumulation of newly synthesized proteins in cultured adult rat ventricular cardiomyocytes. Firstly, we have obtained data showing that 8-bromo-cGMP does not inhibit phosphorylation of S6K1 by PE during short time treatment (10 min to 2 h), but blocks phosphorylation of S6K1 by PE at 6 h; moreover this blocking effect is completely abolished by phosphatase inhibitor Tautomycin. Then, we have demonstrated that PE and cGMP induce sustained and transient increased phosphorylation of ERK, respectively. Moreover, cGMP inhibits PE-induced phosphorylation of ERK during long term treatment (3 and 6h). We have also shown that 8-bromo-cGMP inhibits ROS generation induced by PE. Other effects of PE that could be related to hypertrophy (i.e. increased concentration of upstream binding factor mRNA and decreased concentration of the mRNAs of Atrogin and muscle specific RING finger) were not abolished by 8-bromo-cGMP. We conclude that cGMP analog blocks protein accumulation by inhibiting the sustained phosphorylation of S6K1 via the activation of phosphatases.

Heart failure represents an important cause of death in Western Countries. The pathophysiology of heart failure is mainly associated with abnormalities in intracellular calcium control. We previously showed that Egr-1 negatively regulates expression of sodium-calcium exchanger (NCX) in vivo and in vitro. Here we tested the hypothesis that Egr-1 regulates expression of calcium storage proteins in the sarco-endoplasmic reticulum (SER), calsequestrin (CSQ) and/or ER, calreticulin (CRT) directly or indirectly via Egr-1:NFAT (nuclear factor of activated T-cells) formation. Secondarily, we hypothesized that this will reduce calcium mobilization. We found that undifferentiated 1293F cells, overexpressing Egr-1, have reduced CSQ compared to control H9c2 cells. We demonstrated that Egr-1 negatively regulates CSQ but not CRT expression. The Egr-1 mediated decrease in CSQ is linked to decreased calcium availability. Repression is by a novel NAB-independent (NGFI-A binding protein) activity localized to a.a. region 1-307. We conclude that Egr-1-mediated reductions in calcium storage protein expression alter calcium availability for cardiac contraction/relaxation.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 5 uppsatser.

Dissertation (Ph.D.)--University of South Florida, 2005. / Includes vita. Includes bibliographical references. Also available online as a PDF document.

Dissertation (Ph.D.)--University of South Florida, 2008. / Title from PDF of title page. Document formatted into pages; contains 140 pages. Includes vita. Includes bibliographical references.

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