Abstract Thu071: Vinculin Deficiency Impairs Early Cardiac Development and Alters Mechanosensitive Pathways

Background: Vinculin (Vcl) is a cytoskeletal protein critical for mechanical force transmission in cell-matrix and cell-cell junctions, including those in cardiomyocytes (CMs). Vcl mutations are associated with cardiomyopathies, congenital heart defects (CHDs), and Sudden Unexplained Nocturnal Death Syndrome (SUNDS), yet its role in cardiac development remains poorly understood. Global Vcl knockout (KO) mice exhibit embryonic lethality by E10 with severe cardiac defects, while a prior CM-specific Vcl KO model created in our lab displayed postnatal cardiomyopathy and sudden death. We hypothesized that Vcl is essential for early cardiac maturation. Aim: Investigating Vcl’s impact on mechanical signaling of cardiogenesis. Methods: To investigate Vcl’s role in early cardiogenesis, we generated a novel mouse model (VclcKO) by crossing Vcl fl/fl mice with Xenopus myosin light chain 2-Cre (XMLC2vCre), which induces CM-specific Vcl deletion from the cardiac crescent stage (E7.5 -8). Embryos were evaluated with confocal microscopy, western blotting, mass spectrometry, and qRT-PCR techniques. Results: VclcKO mice exhibited embryonic lethality by E12.5, with delayed cardiac maturation, a thinned compact layer, and abnormal trabeculation, suggesting that Vcl is essential for early cardiac development. Proteomic data showed dysregulation of actin and cytoskeletal-associated proteins and altered kinase/phosphatase signaling, suggesting compensatory mechanisms in response to Vcl deficiency. qRT-PCR of cKO showed ~70% reduced (p<0.015) mechanosensitive pathway transcripts such as SRF-MRTF-A and Hippo-YAP/TAZ. Ongoing research will further dissect the molecular consequences of CM Vcl deficiency on heart development. Conclusion: This study comprehensively links CM Vcl loss to disrupted mechanotransduction and impaired cardiac maturation, advancing understanding of its role in heart development and postnatal cardiomyopathies.