Calcineurin and calcium/calmodulin-dependent protein kinase activate distinct metabolic gene regulatory programs in cardiac muscle.
To learn more about the targets of Cn (Cn) and calcium/calmodulin-dependent protein kinase in cardiac muscle, we investigated their actions in cultured cardiac myocytes and the hearts of mice in vivo. Adenoviral-mediated expression of constitutively active forms of either pathway induced expression of peroxisome proliferator-activated receptor gamma coactivator 1alpha, a transcriptional coactivator involved in the control of multiple cellular energy metabolic pathways in cardiac myocytes. Transcriptional profiling studies demonstrated that Cn and calcium/calmodulin-dependent protein kinase activate distinct but overlapping metabolic gene regulatory programs. Expression of the nuclear receptor, peroxisome proliferator-activated receptor alpha, was markedly increased by Cn, but not calcium/calmodulin-dependent protein kinase, providing one mechanism whereby cellular fatty acid utilization genes are selectively activated by Cn. Transfection experiments demonstrated that Cn directly activates the mouse peroxisome proliferator-activated receptor alpha gene promoter. Co-transfection "add-back" experiments demonstrated that the transcription factors, myocyte enhancer factors 2C or 2D, were sufficient to confer Cn-mediated activation of the peroxisome proliferator-activated receptor alpha gene. Cn was also shown to directly activate a known peroxisome proliferator-activated receptor alpha target, muscle-type carnitine palmitoyltransferase I, providing a second mechanism by which Cn activates genes of cellular fatty acid utilization. Lastly, the gene expression of peroxisome proliferator-activated receptor gamma coactivator 1alpha and peroxisome proliferator-activated receptor alpha was reduced in the hearts of mice with cardiac-specific ablation of the Cn regulatory subunit. These data support a role for calcium-triggered signaling pathways in the regulation of cardiac energetics and identify pathway-specific control of metabolic targets.
Schaeffer
Paul J
PJ
Center for Cardiovascular Research and Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Wende
Adam R
AR
Magee
Carolyn J
CJ
Neilson
Joel R
JR
Leone
Teresa C
TC
Chen
Feng
F
Kelly
Daniel P
DP
D000818:Animals; D019703:Calcineurin / Q000235:genetics* / Q000378:metabolism*; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008817:Mice, Mutant Strains; D032386:Myoblasts, Cardiac / Q000166:cytology / Q000502:physiology*; D020411:Oligonucleotide Array Sequence Analysis; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology
D006360:Heat-Shock Proteins; C486497:PPARGC1A protein, human; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D018160:Receptors, Cytoplasmic and Nuclear; D014157:Transcription Factors; D017868:Cyclic AMP-Dependent Protein Kinases; D019703:Calcineurin