USP5: New Hope for Heart Disease

Researchers at the Max Planck Institute for Heart and Lung Research, alongside King's College London, have uncovered the critical role of the enzyme **ubiquitin-specific peptidase 5 (USP5)** in maintaining heart health. The study, published in *Science Advances*, demonstrates that low levels of USP5 in mice lead to **dilated cardiomyopathy**, a condition characterized by an enlarged heart and reduced pumping capacity. **USP5** is essential for recycling *ubiquitin*, a molecular marker that tags proteins for degradation, thus preventing the accumulation of protein 'junk' in heart cells. Through genetic manipulation, researchers deactivated **USP5** in the heart muscle cells of adult mice, resulting in a significant increase in heart size and reduction in function. Conversely, increasing USP5 levels cleared protein build-up and improved heart condition under stress, such as high blood pressure. This breakthrough highlights the potential of USP5 as a target for new heart disease therapies, specifically for conditions caused by misfolded protein accumulation. The study marks the first evidence of ubiquitin chain recycling's role in dilated cardiomyopathy. Moving forward, researchers plan to explore the mechanisms leading to USP5 loss and its potential in drug development. Success in modulating USP5 levels could pave the way for new treatments for a variety of heart diseases.