JUVENILE MOUSE MODEL OF DELAYED ANTHRACYCLINE CARDIOTOXICITY
Birgitta Asa
San Diego State Universitycity: San Diego country: United States (us)
Grant 5R01HL092136-04 from National Heart, Lung, And Blood Institute
Keywords: ing; Adolescent; Adult; Age; angiogenesis; Animal Model; Anthracyclines; Area; base; Blood capillaries; Blood Vessels; Bone Marrow; Bone Marrow Stem Cell; Cancer Survivor; capillary; Cardiac; Cardiac Myocytes; Cardiomyopathies; Cardiotoxicity; Cell Proliferation; chemotherapeutic agent; chemotherapy; Child; Childhood; CSF3 gene; density; Development; Dose; Doxorubicin; effective therapy; Engraftment; Environment; Exercise; Exposure to; Failure (biologic function); Growth; Growth Factor; Hair; Hair follicle structure; Heart; Heart failure; Histologic; Home environment; Homing; Hypertrophy; Impairment; In Vitro; in vivo; Indium; Infarction; Injury; Insulin-Like Growth Factor I; Investigation; irradiation; Left; Light; Malignant Childhood Neoplasm; Marrow; Mitochondria; Molecular; mouse model; Mus; Muscle Cells; Myocardial; Myocardium; Pathologic; Patients; Physiological; Play; Pregnancy; prevent; repaired; response; response to injury; Risk; Role; senescence; stem cell population; stem cell therapy; Stem cells; Structure; Survival Rate; Therapeutic; Time; tumor; Tumor Angiogenesis; Ventricular; Work; Workload; young adult
Relevance: Anthracycline-induced cardiotoxic effects are a serious problem among patients who survive childhood cancer and there is an urgent need to avoid such effects. Currently, satisfactory therapy for doxorubicin- induced cardiomyopathy is lacking and increased understanding of the molecular mechanisms of anthracycline action is necessary for the development of effective treatments against anthracycline-induced cardiotoxicity. This proposal establishes for the first time an animal model of childhood doxorubicin exposure leading to heart failure in adulthood, and will evaluate the effects of doxorubicin on cardiac stem cells
Project start date: 2008-12-19
Project end date: 2013-11-30
Budget start date: 1-DEC-2011
Budget end date: 30-NOV-2012
5R01HL092136-04 (2012): $333011
Sponsored Links Excellgen http://Excellgen.com
Grants awarded to Birgitta Asa
MCL-1 AS AN ESSENTIAL REGULATOR OF CARDIAC MITOCHONDRIAL FUNCTION
Birgitta Asa
University Of California San Diegocity: La Jolla country: United States (us)
Grant 5R01HL101217-02 from National Heart, Lung, And Blood Institute
Abstract: Mitochondria play critical roles in both the life and death of cardiac myocytes. They are important generators of energy, providing ATP through oxidative phosphorylation. However, mitochondria also monitor complex information from the environment and intracellular milieu, including the presence or absence of growth factors, oxygen, reactive oxygen species, and DNA damage. Thus, it is not surprising that there is a strong link between mitochondrial dysfunction and cardiovascular disease. The Bcl-2 family proteins control mitochondrial outer membrane permeabilization and play a key role in regulating the mitochondrial apoptotic pathway. Mcl-1 is an anti-apoptotic Bcl-2 protein which is expressed at higher levels in the myocardium compared to other anti-apoptotic proteins such as Bcl-2 and Bcl-XL. Surprisingly, little is known about how Mcl-1 regulates cell survival in myocardial cells. We therefore generated a heart specific inducible knockout of Mcl-1 and discovered that loss of Mcl-1 in cardiac myocytes led to rapid mitochondrial dysfunction and cell death. Surprisingly, Mcl-1 deficient myocytes displayed signs of necrotic cell death instead of apoptotic cell death, suggesting that besides its anti-apoptotic role, Mcl-1 has an essential but yet unidentified role in maintaining mitochondrial function in cardiac myocytes. To better understand the physiological function(s) of Mcl-1 in the heart, we plan to identify new proteins that interact with Mcl-1 and elucidate the functional significance of this interaction in Aim 1. Mitochondria are highly dynamic organelles that are constantly undergoing fission and fusion, and these processes play important roles in the normal turnover of mitochondria. Defects in these processes can affect mitochondrial function and cell survival. We found that Mcl-1 can influence mitochondrial dynamics by inducing fission. Thus, in Aim 2, we will examine if Mcl-1 regulates mitochondrial dynamics by recruiting components of the mitochondrial fission machinery and whether this process is essential for normal bioenergetic function. Removal of dysfunctional mitochondria by autophagy is an essential process, and defects in this pathway in the heart lead to accumulation of dysfunctional mitochondria and development of heart failure. Ultrastructural analysis revealed a lack of mitochondrial autophagy in myocytes lacking Mcl-1, suggesting that Mcl-1 deficient myocytes are not delivering damaged mitochondria to autophagosomes. In Aim 3, we will investigate the role of Mcl-1 in regulating mitochondrial autophagy. Mitochondrial turnover decreases with age resulting in accumulation of dysfunctional mitochondria in the cell. Therefore, in Aim 4, we will investigate if enhanced levels of Mcl-1 will protect against cardiomyopathic challenge and as well as prolong survival of cardiac myocytes in aging using wild type and Mcl-1 transgenic mice. This project will provide important new insights into mitochondrial function in cardiac myocytes and how mitochondrial dysfunction contributes to development of cardiovascular disease. (End of )
Keywords: ing; Affect; Age; Aging; Apoptotic; Autophagocytosis; Autophagosome; Binding (Molecular Function); Bioenergetics; Cardiac; Cardiac Myocytes; Cardiovascular Diseases; Cell Death; Cell Survival; Cells; Cessation of life; Complex; Contracts; Defect; Development; Dissociation; DNA Damage; Environment; Excision; Extracellular Space; Growth Factor; Heart; Heart failure; insight; Knock-out; Lead; Life; Link; MCL1 protein; meetings; Mitochondria; mitochondrial autophagy; mitochondrial dysfunction; Monitor; Muscle Cells; Myocardial; Myocardium; Necrosis; Organelles; Outer Mitochondrial Membrane; overexpression; Oxidative Phosphorylation; Oxygen; parkin gene/protein; Pathogenesis; Pathway interactions; Permeability; Physiological; Play; Process; Protein Family; Proteins; Proteomics; Quality Control; Reactive Oxygen Species; Recruitment Activity; response; Role; Rupture; Stress; Swelling; Testing; Transgenic Mice
Relevance: Mitochondria are important in providing energy for the contracting myocyte, but mitochondrial dysfunction occurs early in the pathogenesis of heart failure. We found that the anti-apoptotic protein Mcl-1 is essential for normal mitochondrial function in cardiac myocytes and in this proposal, we will investigate the hypothesis that Mcl-1 is essential for mitochondria quality control by regulating mitochondrial dynamics and autophagy. This project will provide important new insights into mitochondrial function in cardiac myocytes and how mitochondrial dysfunction contributes to development of cardiovascular disease
Project start date: 2010-05-01
Project end date: 2014-03-31
Budget start date: 1-APR-2011
Budget end date: 31-MAR-2012
PFA/PA: RFA-HL-10-002
5R01HL101217-02 (2011): $572047
3R01HL101217-01S1 (2011): $14502
ROLE OF BNIP3 IN MYOCARDIAL ISCHEMIA/REPERFUSION
Birgitta Asa
University Of California San Diegocity: La Jolla country: United States (us)
Grant 5R01HL087023-06 from National Heart, Lung, And Blood Institute
Abstract: Cell death by apoptosis is recognized as a major component of ischemia/reperfusion (I/R) injury. Activation of cell death pathways during I/R leads to loss of terminally differentiated cardiac myocytes, thus contributing to the development of heart failure. The Bcl-2 family proteins play an important role in regulating the mitochondrial pathway of apoptosis in the myocardium. BnipS is a pro-apoptotic member of the Bcl-2 family and is localized primarily to the mitochondria in myocardial cells. Overexpression of BnipS leads to mitochondrial dysfunction and cell death in various cell types, including neonatal cardiac myocytes. Elevated levels of BnipS protein have been reported in vivo in animal models of acute ischemia and heart failure. We have found that BnipS is expressed at substantially in the adult myocardium and our preliminary data indicate that BnipS plays a significant role in l/R-mediated cell death by activation of the mitochondrial pathway. Moreover, we have found that overexpression of BnipS causes extensive fragmentation of the mitochondrial network along with upregulation of autophagy, and that BnipS is subjected to proteolysis in cells subjected to hypoxia or simulated I/R. (8). In this proposal, we will explore the hypothesis that BnipS functions as a redox sensor that is activated by increased oxidative stress during I/R, leading to mitochondrial dysfunction and subsequent cell death. This hypothesis will be explored with the following specific aims 1. Investigate the role of BnipS as a mitochondrial sensor of oxidative stress 2. Define the molecular mechanism(s) by which BnipS mediates mitochondrial fragmentation 3. Elucidate the role of autophagy in BnipS-mediated cell death 4. Characterize the role of BnipS proteolysis in response to I/R Our long-term goal is to understand the pathways that contribute to I/R injury and the results from this proposal will provide new insights into the pathways of apoptosis and their regulation in the heart. Further understanding of how BnipS functions in the heart has the potential to identify new therapeutic targets to treat or prevent heart disease
Keywords: Acute; Adult; Amino Acid Sequence; Animal Model; Apoptosis; Apoptotic; Autophagocytosis; Autophagosome; Cardiac Myocytes; caspase; Caspase Inhibitor; Cell Death; Cell Fractionation; cell type; Cells; cellular imaging; Chronic; Coupled; Cysteine; cytochrome c; Data; Development; disulfide bond; Family; Goals; Heart; Heart Diseases; Heart failure; Heterodimerization; Homodimerization; Hydrogen Peroxide; Hypoxia; in vivo; insight; Ischemia; Lead; Life; Mediating; member; Mitochondria; mitochondrial dysfunction; mitochondrial permeability transition pore; Molecular; Muscle Cells; Myocardial; Myocardial Ischemia; Myocardium; N-terminal; Neonatal; new therapeutic target; Outer Mitochondrial Membrane; overexpression; oxidation; Oxidation-Reduction; Oxidative Stress; Pathway interactions; Peptide Hydrolases; Peptide Sequence Determination; Play; prevent; Production; programs; Protein Family; Proteins; Proteolysis; Reactive Oxygen Species; Regulation; Reperfusion Injury; Reperfusion Therapy; Reporting; Research Personnel; response; Role; Scanning; sensor; Simulate; Site; Staging; Stress; Structure; Transmission Electron Microscopy; Up-Regulation (Physiology)
Project start date: 2007-07-19
Project end date: 2012-06-30
Budget start date: 1-JUL-2011
Budget end date: 30-JUN-2012
5R01HL087023-06 (2011): $347625