Abstract
AimsThe adapter protein p130Cas, encoded by the Bcar1 gene, is a key regulator of cell movement, adhesion, and cell cycle control in diverse cell types. Bcar1 constitutive knockout mice are embryonic lethal by embryonic days (E) 11.5–12.5, but the role of Bcar1 in embryonic development remains unclear. Here, we investigated the role of Bcar1 specifically in cardiovascular development and defined the cellular and molecular mechanisms disrupted following targeted Bcar1 deletions.Methods and resultsWe crossed Bcar1 floxed mice with Cre transgenic lines allowing for cell-specific knockout either in smooth muscle and early cardiac tissues (SM22-Cre), mature smooth muscle cells (smMHC-Cre), endothelial cells (Tie2-Cre), second heart field cells (Mef2c-Cre), or neural crest cells (NCC) (Pax3-Cre) and characterized these conditional knock outs using a combination of histological and molecular biology techniques. Conditional knockout of Bcar1 in SM22-expressing smooth muscle cells and cardiac tissues (Bcar1SM22KO) was embryonically lethal from E14.5–15.5 due to severe cardiovascular defects, including abnormal ventricular development and failure of outflow tract (OFT) septation leading to a single outflow vessel reminiscent of persistent truncus arteriosus. SM22-restricted loss of Bcar1 was associated with failure of OFT cushion cells to undergo differentiation to septal mesenchymal cells positive for SMC-specific α-actin, and disrupted expression of proteins and transcription factors involved in epithelial-to-mesenchymal transformation (EMT). Furthermore, knockout of Bcar1 specifically in NCC (Bcar1PAX3KO) recapitulated part of the OFT septation and aortic sac defects seen in the Bcar1SM22KO mutants, indicating a cell-specific requirement for Bcar1 in NCC essential for OFT septation. In contrast, conditional knockouts of Bcar1 in differentiated smooth muscle, endothelial cells, and second heart field cells survived to term and were phenotypically normal at birth and postnatally.ConclusionOur work reveals a cell-specific requirement for Bcar1 in NCC, early myogenic and cardiac cells, essential for OFT septation, myocardialization and EMT/cell cycle regulation and differentiation to myogenic lineages.
Highlights
The adapter protein p130Cas, encoded by the Bcar[1] gene, plays a critical role in chemotactic signalling in diverse cell types, through regulation of the actin cytoskeleton and its function in multimolecular complexes of focal adhesions 1, 2
We crossed Bcar[1] floxed mice with Cre transgenic lines allowing for cell-specific knockout either in smooth muscle and early cardiac tissues (SM22-Cre), mature smooth muscle cells, endothelial cells (Tie2-Cre), second heart field cells (Mef2c-Cre), or neural crest cells (NCC) (Pax3-Cre) and characterised these conditional knock outs using a combination of histological and molecular biology techniques
Conditional knockout of Bcar[1] in SM22-expressing smooth muscle cells and cardiac tissues (Bcar1SM22KO) was embryonically lethal from E14.5-15.5 due to severe cardiovascular defects, including abnormal ventricular development and failure of outflow tract (OFT) septation leading to a single outflow vessel reminiscent of persistent truncus arteriosus
Summary
The adapter protein p130Cas, encoded by the Bcar[1] gene, plays a critical role in chemotactic signalling in diverse cell types, through regulation of the actin cytoskeleton and its function in multimolecular complexes of focal adhesions 1, 2. Bcar1-null embryos died in utero between embryonic days (E) 11.5 to 12.5, exhibiting severe defects in development of the heart and prominent dilation of major blood vessels 8. These findings showed that Bcar1/p130Cas is essential for normal embryonic development, but did not indicate whether defects observed in Bcar1-null embryos arose from a specific role of Bcar1/p130Cas in cardiovascular development or were an indirect effect of complete organismal loss of Bcar[1], and provided no indication of the molecular or cellular mechanisms involved. Mutant mice with a global deletion of the Bcar1/p130Cas exon 2-encoded SH3 domain died in utero at E12.5-13.5, with severe liver degeneration, but display no defects in development of the heart or other major organs 9. Studies of conditional knock outs for Bcar[1] do not account for the embryonic lethality displayed by Bcar1-null mice
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
