BIOENERGETIC REGULATION OF CARDIAC PROGENITOR CELLS

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. A restructuring of glycolysis and mitochondrial energetics is thought to be required for stem cell differentiation, supporting the view that phenotype specification requires the coordination of genetic circuits and developmental bioenergetics. This implies that metabolic diseases such as diabetes may be particularly destructive to cardiac progenitor cells (CPCs), thereby limiting their ability to differentiate and tolerate stress in the milieu of the diseased myocardium. We plan to examine the role of mitogens in mediating the changes in glycolysis and mitochondrial energetics required for CPC differentiation. The general hypothesis is that the developmental cues that relate mitogen signaling with energetics are disrupted in diabetes, thereby preventing differentiation of CPCs into cardiomyocytes. The specific aims are to: 1. Examine the effects of mitogens on CPC energetics. Because mitogens such as insulin and IGF-1 play important roles in CPC homing and differentiation, we will examine how the absence and presence of these mitogens affect glycolytic flux and mitochondrial bioenergetics. The effect of insulin resistance on energetics will be examined, and cardiomyocyte differentiation will be monitored by confocal microscopy and flow cytometry. 2. Determine how glycolysis regulates CPC growth and differentiation. Using pharmacological and molecular interventions (e.g., koningic acid and PFK-2 knockdown or overexpression), we will examine the role of glycolysis in CPC growth and differentiation under substrate conditions that mimic the normal and diabetic phenotype. Energetics will be examined by extracellular flux analysis and differentiation into the cardiac lineage will be measured by expression of GFP-Nkx2.5. 3. Assess whether reimplantation of energetically competent CPCs increases their therapeutic efficacy. CPCs with high glycolytic and/or mitochondrial capacities will be reimplanted in the infarcted heart. Myocardial function will be evaluated by echocardiography and engraftment will be analyzed by confocal microscopy in heart tissue sections.