PROJECT SUMMARY/ABSTRACT Laminopathies, or LMNA mutations, are hereditary diseases that alter the integrity of the cellular biomechanics and they are associated with a wide range of diseases including neuromuscular, cardiac, metabolic disorders and premature aging syndromes. Laminopathies are caused by mutations in the LMNA gene, which encodes for the nuclear envelope proteins, lamin A and C. Most LMNA mutations affect skeletal and cardiac muscle by mechanisms that remain incompletely understood. However, since the lamins stabilize mechanically the nucleus, LMNA mutations alter the integrity of the cellular biomechanics. It is believed that mutated A-type lamins disrupt the integrity of the cell nuclear membrane, resulting in nuclear breakage and cell death in tissues exposed to mechanical stress. In addition, LMNA mutations alter the interaction between the nucleus and the cytoskeleton, “perturbing cellular force transmission” and preventing nuclear movement of proteins that are needed for healthy cell function. During the past three years we have investigated the biomechanics of LMNA mutations in cardiac cells using atomic force microscopy (AFM). LMNA mutations perturb cardiomyocyte gene expression and biomechanical properties and are the #2 cause of DCMs, leading to heart failure (HF), arrhythmias, transplantation, and premature death. DCMs are heart muscle diseases that account for 60% of cardiomyopathy cases, are frequently genetic, and are the #1 and #3 causes of heart transplantation and heart failure. Tragically, DCM strikes young people causing disproportionately high morbidity (medically, socially, economically, etc.). There exists a clear need for better DCM treatments for the nearly 1M affected US adults (~1:250). ~50% of cases of DCM are genetic due to >50 DCM genes, including LMNA. LMNA mutations cause 8% of DCM with a malignant arrhythmia-prone phenotype, prompting defibrillator implantation (ACC/AHA/HFSA 2017 Guidelines). Since DCM is a disease characterized by biomechanical impairment of the heart, it is pivotal to understand the cellular biomechanics and biophysics of this pathology which may bring novel insights that would benefit patient treatments. In this work we propose to assess how mechanical stresses affect cardiac spheroids carrying the LMNA mutation. We hypothesis that mechanobiological pathways have the key to find novel therapeutics for LMNA mutations.