Examination of cardiovascular function in mice with epicardial-specific deletions of Crk-CrkL adaptor proteins
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 the development of the cardiovascular system. They mediate signaling pathways involved in biological processes such as cell migration, proliferation, apoptosis, adhesion, survival, and differentiation. Both Crk and CrkL share functions in the endocardial lineage for atrioventricular valve development. Our lab has observed Crk and CrkL expression throughout the developing mouse heart including the epicardium and epicardium-derived cells (EPDCs), which give rise to the coronary vascular cells and cardiac fibroblasts. Investigators have demonstrated that deletion of Crk-CrkL genes causes various cardiovascular structural defects. We observed embryonic lethality due to septal defects in mice at mid-to-late gestation with global deletion of Crk and Crk. To determine the impact of Crk and CrkL on cardiovascular function, we devised a strategy to achieve tissue-specific conditional deletion of these proteins that enable these mice to survive to adulthood for analysis of physiological parameters.
OBJECTIVE: The goal of our study was to determine the impact of Crk and CrkL in the epicardium and its derivatives to control and maintain cardiovascular function in the adult mouse heart.
METHODS: We developed a tissue-specific strategy to conditionally delete one or both Crk and CrkL alleles from the epicardium and EPDCs of the mouse heart with Wilms’ tumor 1 (Wt1) Cre-driven recombinase. The mice obtained from this breeding strategy included Crklox/lox/CrkLlox/lox control mice, 2 allele knockouts (Crklox/+/CrkLlox/+; Wt1-Cre), 3 allele knockouts (Crklox/+/CrkLlox/lox ;Wt1-Cre or Crklox/lox/CrkLlox/+ ;Wt1-Cre), and 4 allele knockouts (Crklox/lox/CrkLlox/lox;Wt1-Cre). Cardiovascular structure and functional parameters were examined in anesthetized mice via a series of cardiac micro-ultrasounds performed at 4, 8, and 12 months of age. We used the Vevo1100 Ultrasound imager to capture parasternal long and short axis views of heart wall motion and coronary blood flow in these mice. These cardiovascular functional parameters were compared between control and Crk-CrkL epicardial-deletion mice. Various measurements were obtained from the images and loops captured at each timepoint including stroke volume, ejection fraction, cardiac output, end-systolic volume, and end-diastolic volume. Analysis was performed using Vevo Lab analysis software.
RESULTS: Echocardiogram analysis of 4-month-old mice revealed slight increases in contractility of Crk-CrkL epicardial-deletion mice compared to control hearts. In addition, we observed a mild increase in coronary velocity time integral in Crk/CrkLdel/+ mouse hearts compared to the control mice. This parameter indicates the distance blood travels within the coronary arteries.
CONCLUSION: Our data demonstrates the importance of Crk and CrkL expression in the epicardium and its derivatives. We speculate Crk-CrkL deletions may impact contractility and coronary blood flow of the heart as a result of the increased demands placed on the systemic circulation to maintain adequate blood flow. In future studies, we will explore the molecular and physiologic mechanisms that contribute to the increased systemic demands in Crk-CrkL epicardial-deletion mice.
Embargo Period
5-20-2025
Examination of cardiovascular function in mice with epicardial-specific deletions of Crk-CrkL adaptor proteins
Philadelphia, PA
INTRODUCTION: Crk and CrkL are intracellular cytoplasmic adaptor proteins that contribute to the development of the cardiovascular system. They mediate signaling pathways involved in biological processes such as cell migration, proliferation, apoptosis, adhesion, survival, and differentiation. Both Crk and CrkL share functions in the endocardial lineage for atrioventricular valve development. Our lab has observed Crk and CrkL expression throughout the developing mouse heart including the epicardium and epicardium-derived cells (EPDCs), which give rise to the coronary vascular cells and cardiac fibroblasts. Investigators have demonstrated that deletion of Crk-CrkL genes causes various cardiovascular structural defects. We observed embryonic lethality due to septal defects in mice at mid-to-late gestation with global deletion of Crk and Crk. To determine the impact of Crk and CrkL on cardiovascular function, we devised a strategy to achieve tissue-specific conditional deletion of these proteins that enable these mice to survive to adulthood for analysis of physiological parameters.
OBJECTIVE: The goal of our study was to determine the impact of Crk and CrkL in the epicardium and its derivatives to control and maintain cardiovascular function in the adult mouse heart.
METHODS: We developed a tissue-specific strategy to conditionally delete one or both Crk and CrkL alleles from the epicardium and EPDCs of the mouse heart with Wilms’ tumor 1 (Wt1) Cre-driven recombinase. The mice obtained from this breeding strategy included Crklox/lox/CrkLlox/lox control mice, 2 allele knockouts (Crklox/+/CrkLlox/+; Wt1-Cre), 3 allele knockouts (Crklox/+/CrkLlox/lox ;Wt1-Cre or Crklox/lox/CrkLlox/+ ;Wt1-Cre), and 4 allele knockouts (Crklox/lox/CrkLlox/lox;Wt1-Cre). Cardiovascular structure and functional parameters were examined in anesthetized mice via a series of cardiac micro-ultrasounds performed at 4, 8, and 12 months of age. We used the Vevo1100 Ultrasound imager to capture parasternal long and short axis views of heart wall motion and coronary blood flow in these mice. These cardiovascular functional parameters were compared between control and Crk-CrkL epicardial-deletion mice. Various measurements were obtained from the images and loops captured at each timepoint including stroke volume, ejection fraction, cardiac output, end-systolic volume, and end-diastolic volume. Analysis was performed using Vevo Lab analysis software.
RESULTS: Echocardiogram analysis of 4-month-old mice revealed slight increases in contractility of Crk-CrkL epicardial-deletion mice compared to control hearts. In addition, we observed a mild increase in coronary velocity time integral in Crk/CrkLdel/+ mouse hearts compared to the control mice. This parameter indicates the distance blood travels within the coronary arteries.
CONCLUSION: Our data demonstrates the importance of Crk and CrkL expression in the epicardium and its derivatives. We speculate Crk-CrkL deletions may impact contractility and coronary blood flow of the heart as a result of the increased demands placed on the systemic circulation to maintain adequate blood flow. In future studies, we will explore the molecular and physiologic mechanisms that contribute to the increased systemic demands in Crk-CrkL epicardial-deletion mice.