Wnt1/β-Catenin Injury Response Activates the Epicardium and Cardiac Fibroblasts to Promote Cardiac Repair

The document presents a study on the importance of Wnt1/βcatenin signaling in cardiac repair after acute ischemic injury. The study found that Wnt1 is upregulated in the epicardium and by cardiac fibroblasts in the injured heart, leading to epicardial activation, expansion, and epithelial-mesenchymal transition (EMT) to generate cardiac fibroblasts. These fibroblasts proliferate and express pro-fibrotic genes in response to Wnt1. Disruption of this signaling pathway resulted in impaired cardiac function and healing, with decreased epicardial expansion, EMT, and increased ventricular dilatation after injury. The study used mouse models with varying numbers of animals per group, including some experiments with 8 and others with 3 animals per group. It concluded that Wnt1/βcatenin signaling is critical for cardiac repair, suggesting that targeting this pathway could influence fibrosis and regeneration following cardiac injury.