Disclosing CCBE1 role in Cardiac Differentiation of Human Pluripotent Stem Cells

• Autor(a) principal: Vicente, Pedro Miguel Gomes Gião
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/53681
• topic: Cardiovascular Disease; human induced Pluripotent Stem Cells (hiPSCs); CCBE1; CRISPRi; Cardiomyocytes; Loss-of-function Studies; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Química

Cardiovascular diseases (CVD) are the leading cause of death worldwide. Within CVDs, myocardial infarction (MI) is associated with a massive and irreversible loss of cardiomyocytes (CM). An in-depth comprehension of key cellular mechanisms and molecules involved in cardiogenesis is fundamental to improve cardiac therapies by exposing novel therapeutic targets. CCBE1, a collagen and calcium-EGF biding domain 1 protein, was identified to be expressed in mouse heart precursors. Mutations in CCBE1 have been associated with Hennekam syndrome, which is characterized by abnormal lymphatic system and congenital heart defects. However, the CCBE1 functional role in cardiac specification is still unknown. Therefore, the main aim of this thesis was to unveil CCBE1 role in CM and Endothelial cells (EC) specification. For this purpose, a modified hiPSC line displaying the CRISPR interference technology (CRISPRi) was used to selectively knockdown (KD) CCBE1 gene expression along CM and EC differentiation. We showed that CCBE1 downregulation did not affect hiPSCs growth, morphology and stemness. Nonetheless, a significant reduction on gene expression of cardiac troponin T2 gene (TNNT2) and lower gene expression ratios of cardiac troponin I isoforms (TNNI3:TNNI1) and myosin heavy chains (MYH7:MYH6) were detected in CMs derived from CRISPRi-CCBE1 KD cell line at day 15. Ultrastructural changes were also observed in this condition, CMs presented lower sarcomere length and alignment, indicating a more immature state. In contrast, EC differentiation was not affected by CCBE1 KD, with no impact on EC morphology or gene expression levels. Therefore, CCBE1 seems to have a key role on CM specification and maturation. Moreover, we successfully selected hiPSC clonal populations with higher level of CCBE1 KD for future studies. This work may contribute with new insights towards the development of CCBE1-mediated therapeutic strategies for cardiac regenerative medicine.