Impact of epicardial-specific Crk-CrkL genetic deletions on cardiac structure and function in mice

Location

Philadelphia, PA

Start Date

30-4-2025 1:00 PM

End Date

30-4-2025 4:00 PM

Description

INTRODUCTION: Crk and CrkL are intracellular cytoplasmic adaptor proteins that contribute to congenital heart disease. They mediate multiple signaling pathways involved in biological processes including cell migration, proliferation, apoptosis, adhesion, survival, and differentiation. Both Crk and CrkL have shared functions in the cardiac neural crest cells for cardiac outflow tract septation as well as shared functions in the endocardial lineage for atrioventricular valve development. Recently, we observed Crk and CrkL expression in the epicardium and epicardium-derived cells (EPDCs) that form the coronary vessels and cardiac fibroblasts in the embryonic mouse heart. The roles of the Crk-CrkL adaptor proteins in the epicardium, its derivatives, and the coronary vasculature have not been established in the adult mammalian heart.

OBJECTIVE: This study aimed to explore the role of Crk and CrkL in the epicardium and its derivatives and their impact on cardiovascular structure and function. More specifically, this study determined whether a correlation existed between the number of Crk-CrkL allelic deletions and the degree of cardiovascular structural and functional alterations in the adult mouse heart.

METHODS: We examined cardiovascular structure and functional parameters in Crklox/lox/CrkLlox/lox control mice and compared them to mice with epicardial-specific deletion of one or both Crk-CrkL alleles with the Wilms’ tumor 1 (Wt1) Cre-drive recombinase that include:

  • 2-allele conditional knockout (2aCKO) manifesting as Crklox/+/CrkLlox/+ ;Wt1-Cre

  • 3 allele conditional knockout (3aCKO) of Crk/CrkL manifesting as Crklox/lox/CrkLlox/+ ; Wt1-Cre or Crklox/+/CrkLlox/lox ;Wt1-Cre

  • 4 allele conditional knockout (4aCKO) of Crk/CrkL manifesting as Crklox/lox/CrkLlox/lox

We acquired a series of physiologic data from 4-, 8-, and 12-month-old mice via high-frequency echocardiographic measurements of parameters of cardiac contractility and cardiac structure that included ejection fraction, cardiac output, left ventricular (LV) mass, anterior wall thickness during systole and diastole, and posterior wall thickness during systole and diastole. We used the VEVO Lab integrated computer software to trace left ventricular borders which yielded measurements for all parameters. These measurements were compiled and compared between both control and Crk-CrkL epicardial-deletion mice in all age groups.

RESULTS: Our lab observed a consistent trend of increased LV mass and marginally increased wall thicknesses in both 2aCKO and 3aCKO mice when compared to control mice. These findings suggest a potential link between the expression of Crk-CrkL and LV hypertrophy.

CONCLUSION: Collectively, these data demonstrate that Crk and CrkL play a vital role in development of the epicardium and its derivatives. Conditional loss of Crk-CrkL from these epicardial tissues appears to impact cardiac structural morphology and function. Furthermore, there is speculation that this may alter how the heart maintains the performance of the systemic circulation. We will conduct future studies to determine the underlying mechanism and whether these structural alterations confer a phenotypic benefit or detriment to the mammalian heart.

Embargo Period

5-20-2025

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COinS
 
Apr 30th, 1:00 PM Apr 30th, 4:00 PM

Impact of epicardial-specific Crk-CrkL genetic deletions on cardiac structure and function in mice

Philadelphia, PA

INTRODUCTION: Crk and CrkL are intracellular cytoplasmic adaptor proteins that contribute to congenital heart disease. They mediate multiple signaling pathways involved in biological processes including cell migration, proliferation, apoptosis, adhesion, survival, and differentiation. Both Crk and CrkL have shared functions in the cardiac neural crest cells for cardiac outflow tract septation as well as shared functions in the endocardial lineage for atrioventricular valve development. Recently, we observed Crk and CrkL expression in the epicardium and epicardium-derived cells (EPDCs) that form the coronary vessels and cardiac fibroblasts in the embryonic mouse heart. The roles of the Crk-CrkL adaptor proteins in the epicardium, its derivatives, and the coronary vasculature have not been established in the adult mammalian heart.

OBJECTIVE: This study aimed to explore the role of Crk and CrkL in the epicardium and its derivatives and their impact on cardiovascular structure and function. More specifically, this study determined whether a correlation existed between the number of Crk-CrkL allelic deletions and the degree of cardiovascular structural and functional alterations in the adult mouse heart.

METHODS: We examined cardiovascular structure and functional parameters in Crklox/lox/CrkLlox/lox control mice and compared them to mice with epicardial-specific deletion of one or both Crk-CrkL alleles with the Wilms’ tumor 1 (Wt1) Cre-drive recombinase that include:

  • 2-allele conditional knockout (2aCKO) manifesting as Crklox/+/CrkLlox/+ ;Wt1-Cre

  • 3 allele conditional knockout (3aCKO) of Crk/CrkL manifesting as Crklox/lox/CrkLlox/+ ; Wt1-Cre or Crklox/+/CrkLlox/lox ;Wt1-Cre

  • 4 allele conditional knockout (4aCKO) of Crk/CrkL manifesting as Crklox/lox/CrkLlox/lox

We acquired a series of physiologic data from 4-, 8-, and 12-month-old mice via high-frequency echocardiographic measurements of parameters of cardiac contractility and cardiac structure that included ejection fraction, cardiac output, left ventricular (LV) mass, anterior wall thickness during systole and diastole, and posterior wall thickness during systole and diastole. We used the VEVO Lab integrated computer software to trace left ventricular borders which yielded measurements for all parameters. These measurements were compiled and compared between both control and Crk-CrkL epicardial-deletion mice in all age groups.

RESULTS: Our lab observed a consistent trend of increased LV mass and marginally increased wall thicknesses in both 2aCKO and 3aCKO mice when compared to control mice. These findings suggest a potential link between the expression of Crk-CrkL and LV hypertrophy.

CONCLUSION: Collectively, these data demonstrate that Crk and CrkL play a vital role in development of the epicardium and its derivatives. Conditional loss of Crk-CrkL from these epicardial tissues appears to impact cardiac structural morphology and function. Furthermore, there is speculation that this may alter how the heart maintains the performance of the systemic circulation. We will conduct future studies to determine the underlying mechanism and whether these structural alterations confer a phenotypic benefit or detriment to the mammalian heart.