Restoration of endogenous transcription factor activity by nuclease-deficient Cas9VPR prevents cardiac failure upon stress

Cardiac remodeling is linked to maladaptive transcriptional networks, but identifying and targeting key factors with potential to reverse these processes is still a challenge. We employed network-based analysis of single cell heart transcriptomes to compute the transcription factor activities triggering heart failure. We found that the regulation of KLF15 activity is a major driver of cardiomyocyte failure. Through the use of CRISPR/nuclease-deficient (d)Cas9-based transcriptional regulation, we demonstrated that restoration of endogenous Klf15 expression and activity in cardiomyocytes was sufficient to mitigate pathological transcriptional reprogramming and preserve cardiac function in mice and human myocardial models. We also showed that KLF15 is a downstream targetable factor in the broad TGFβ-mediated stress response in human cardiomyocytes, controlling transcriptional embryonalization. Lastly, we engineered a therapeutically applicable mini-dCas9VPR variant suitable for adeno-associated viral delivery, eliciting endogenous KLF15 transcriptional activation in human cardiomyocytes. This case study presents a therapeutic strategy for restoring the stress-induced downregulation of essential genes to prevent heart failure with broader implications for other disease contexts.