A Role for PGC-1 Coactivators in the Control of Mitochondrial Dynamics during Postnatal Cardiac Growth
Rationale: Increasing evidence has shown that proper control of mitochondrial dynamics (fusion and fission) is required for high capacity ATP production in heart. The transcriptional coactivators, peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1) α and β have been shown to regulate mitochondrial biogenesis in heart at the time of birth. The function of the PGC-1 coactivators in heart after birth is incompletely understood.
Objective: To assess the role of the PGC-1 coactivators during postnatal cardiac development and in the adult heart in mice.
Methods and Results: Conditional gene targeting was used in mice to explore the role of the PGC-1 coactivators during postnatal cardiac development and in adult heart. Marked mitochondrial structural derangements were observed in hearts of PGC-1α/β-deficient mice during postnatal growth, including fragmentation and elongation, associated with the development of a lethal cardiomyopathy. The expression of genes involved in mitochondrial fusion [mitofusin 1 (Mfn1), optic atrophy 1 (Opa1)] and fission [dynamin-related protein 1 (Drp1), fission protein 1 (Fis1)] was altered in hearts of PGC-1α/β-deficient mice. PGC-lα was shown to directly regulate Mfn1 gene transcription by coactivating the estrogen-related receptor α (ERRα upon a conserved DNA element. Surprisingly, PGC-1α/β deficiency in the adult heart did not result in evidence of abnormal mitochondrial dynamics or heart failure. However, transcriptional profiling demonstrated that the PGC-1 coactivators are required for high level expression of nuclear- and mitochondrial-encoded genes involved in mitochondrial dynamics and energy transduction in adult heart.
Conclusions: These results reveal distinct developmental stage-specific programs involved in cardiac mitochondrial dynamics.
- Received September 6, 2013.
- Revision received December 17, 2013.
- Accepted December 23, 2013.