CRISPR/Cas-based activation of PPARGC1A boosts endogenous mitochondria and enhances cardiac function and recovery after myocardial infarction

Insufficient energy supply, defined by reduced mitochondrial capacity and altered substrate metabolism, has emerged as a key pathological factor in the development of heart failure (HF) after myocardial infarction (MI). Although current therapeutic strategies of revascularization and afterload reduction have been transformative, no strategy directly augments myocardial energy production. In mammalian cells, mitochondrial biogenesis is orchestrated by the activity of multiple genes encoded by both the nuclear and mitochondrial genomes. While the activation of PPARGC1A, a key driver of mitochondrial biogenesis, can increase cellular mitochondria, supraphysiological levels of PPARGC1A result in adverse tissue remodeling and heart function. CRISPR activation (CRISPRa) technologies present a unique opportunity to address these shortcomings, as they enable tunable control over endogenous target gene expression in cells and in vivo. Here, we demonstrate that transcriptional activation of PPARGC1A using CRISPRa increases cellular mitochondria in diverse human cell types. This effect is mediated through the activation of transcriptional programs driving mitochondrial biogenesis, mitochondrial function, and cellular bioenergetics. These activated transcriptional programs synergize to increase ATP production and reserve capacity in human cardiomyocytes. CRISPRa targeting of PPARGC1A in vivo increases cardiac mitochondria to recover heart ejection fraction in an acute-MI model. Furthermore, CRISPRa acts on adult human heart samples to increase PPARGC1A protein levels and cellular mitochondria, elevating general mitochondrial function in both normal and HF-diagnosed hearts. Altogether, these results provide the first proof-of-concept demonstration that endogenous gene activation via CRISPRa can improve heart function after myocardial infarction.