Bonet, FernandoAñez, Sabrina BritoInácio, José ManuelFutschik, Matthias E.Belo, José AntonioBelo, José A.2022-11-042022-11-042022-10-201422-0067PURE: 47564377PURE UUID: 3888234a-b403-4eb9-a270-71dc83df9df9Scopus: 85140819391PubMed: 36293499WOS: 000873097500001http://hdl.handle.net/10362/145250Funding: This work was supported by Fundação para a Ciência e a Tecnologia (FCT) grants (PTDC/MEC-CAR/29590/2017) to JA Belo and by the Scientific Employment Stimulus to JMI (Norma Transitória 8189/2018, FCT), and iNOVA4Health—UIDB/Multi/04462/2013, a program Int. J. Mol. Sci. 2022, 23, 12642 14 of 17 financially supported by Fundação para a Ciência e Tecnologia/Ministério da Educação e Ciência, through national funds and co-funded by FEDER under the PT2020 Partnership Agreement.The epicardium is a single cell layer of mesothelial cells that plays a critical role during heart development contributing to different cardiac cell types of the developing heart through epithelial-to-mesenchymal transition (EMT). Moreover, the epicardium is a source of secreted growth factors that promote myocardial growth. CCBE1 is a secreted extracellular matrix protein expressed by epicardial cells that is required for the formation of the primitive coronary plexus. However, the role of CCBE1 during epicardial development was still unknown. Here, using a Ccbe1 knockout (KO) mouse model, we observed that loss of CCBE1 leads to congenital heart defects including thinner and hyper-trabeculated ventricular myocardium. In addition, Ccbe1 mutant hearts displayed reduced proliferation of cardiomyocyte and epicardial cells. Epicardial outgrowth culture assay to assess epicardial-derived cells (EPDC) migration showed reduced invasion of the collagen gel by EPDCs in Ccbe1 KO epicardial explants. Ccbe1 KO hearts also displayed fewer nonmyocyte/nonendothelial cells intramyocardially with a reduced proliferation rate. Additionally, RNA-seq data and experimental validation by qRT-PCR showed a marked deregulation of EMT-related genes in developing Ccbe1 mutant hearts. Together, these findings indicate that the myocardium defects in Ccbe1 KO mice arise from disruption of epicardial development and function.3948559engCCBE1EMTepicardial derived cellsepicardiumheart developmentmyocardial growthCatalysisMolecular BiologySpectroscopyComputer Science ApplicationsPhysical and Theoretical ChemistryOrganic ChemistryInorganic Chemistryjournal article10.3390/ijms232012642https://www.scopus.com/pages/publications/85140819391