Biology subjects

D'Amato, G.

Publications and source records attributed to D'Amato, G..

4 recordsLinked to original sources

bioRxiv2021

Endocardium-to-coronary artery differentiation during heart development and regeneration involves sequential roles of Bmp2 and Cxcl12/Cxcr4.

Regenerating coronary blood vessels has the potential to ameliorate ischemic heart disease, yet there is currently no method of stimulating clinically effective cardiac angiogenesisis. Endocardial cells-- a particularly plastic cell type during development--line the heart lumen and are natural coronary vessel progenitors. Their intrinsic angiogenic potential is lost in adults, but studying the endocardial- to-coronary developmental pathway could identify methods of re-instating this process in diseased hearts. Here, we use a combination of mouse genetics and scRNAseq of lineage-traced endothelial cells to identify novel regulators of endocardial angiogenesis and precisely assess the role of Cxcl12/Cxcr4 signaling. Time-specific lineage tracing demonstrated that endocardial cells differentiated earlier than previously thought, largely at mid-gestation. A new mouse line reporting the activity of Cxcr4 revealed that, despite widespread Cxcl12 and Cxcr4 expression, only a small subset of these coronary endothelial cells activated the receptor, which were mostly in arteries. In accordance with these two findings, Cxcr4 deletion in the endocardial lineage only affected artery formation and only when deleted before mid-gestation. Integrating scRNAseq data of coronary endothelial cells from the endocardial lineage at both mid- and late-gestation identified a transitioning population that was specific to the earlier timepoint that specifically expressed Bmp2. Recombinant Bmp2 stimulated endocardial angiogenesis in an in vitro explant assay and in neonatal mouse hearts upon myocardial infarction. Our data shed light on how understanding the molecular mechanisms underlying endocardial-to-coronary transitions can identify new potential therapeutic targets that could promote revascularization of the injured heart.

developmental biology↗

bioRxiv2021

Coronary blood vessels from distinct origins converge to equivalent states during mouse and human development

Most cell fate trajectories during development follow a diverging, tree-like branching pattern, but the opposite can occur when distinct progenitors contribute to the same cell type. During this convergent differentiation, it is unknown if cells "remember" their origins transcriptionally or whether this influences cell behavior. Most coronary blood vessels of the heart develop from two different progenitor sources--the endocardium (Endo) and sinus venosus (SV)--but whether transcriptional or functional differences related to origin are retained is unknown. We addressed this by combining lineage tracing with single-cell RNA sequencing (scRNAseq) in embryonic and adult mouse hearts. Shortly after coronary development begins, capillary ECs transcriptionally segregated into two states that retained progenitor-specific gene expression. Later in development, when the coronary vasculature is well-established but still remodeling, capillary Ecs again segregated into two populations, but transcriptional differences were primarily related to tissue localization rather than lineage. Specifically, ECs in the heart septum expressed genes indicative of increased local hypoxia and decreased blood flow. Adult capillary ECs were more homogeneous with respect to both lineage and location. In agreement, SV- and Endo-derived ECs in adult hearts displayed similar responses to injury. Finally, scRNAseq of developing human coronary vessels indicated that the human heart followed similar principles. Thus, over the course of development, transcriptional heterogeneity in coronary ECs is first influenced by lineage, then by location, until heterogeneity declines in the homeostatic adult heart. These results highlight the plasticity of ECs during development, and the validity of the mouse as a model for human coronary development.

developmental biology↗

bioRxiv2020

Dach1 extends artery networks and protects against cardiac injury

Coronary artery disease (CAD) is the leading cause of death worldwide, but there are currently no available methods to stimulate growth or regeneration of artery networks in diseased hearts. Studying how arteries are built during embryonic development could illuminate strategies for re-building these vessels in the setting of ischemic heart disease. We previously found, using loss-of-function experiments, that the transcription factor Dach1 is required for coronary artery development in mouse embryos. Here, we report that Dach1 overexpression in endothelial cells (ECs) extended coronary arteries and improved survival and heart function in adult mice following myocardial infarction (MI). Dach1 overexpression increased the length and number of arterial end branches, in both heart and retinal vasculature, by causing additional capillary ECs to differentiate into arterial ECs and contribute to growing arteries. Single-cell RNA sequencing (scRNAseq) of ECs undergoing Dach1-induced arterial specification indicated that it potentiated normal artery differentiation, rather than functioning as a master regulator of artery cell fate. ScRNAseq also showed that normal arterial differentiation is accompanied by repression of lipid metabolism genes, which were also repressed by Dach1 prior to arterialization. Together, these results demonstrate that increasing the expression level of Dach1 is a novel pathway for driving specification of artery ECs and extending arterial vessels, which could be explored as a means of increasing artery coverage to mitigate the effects of CAD.

developmental biology↗

bioRxiv2018

Myocardial Notch-Rbpj deletion does not affect heart development or function

During vertebrate cardiac development NOTCH signaling activity in the endocardium is essential for the crosstalk between endocardium and myocardium that initiates ventricular trabeculation and valve primordium formation. This crosstalk leads later to the maturation and compaction of the ventricular chambers and the morphogenesis of the cardiac valves, and its alteration may lead to disease. Although endocardial NOTCH signaling has been shown to be crucial for heart development, its physiological role in the myocardium has not been clearly established. Here we have used a genetic strategy to evaluate the role of NOTCH in myocardial development. We have inactivated the unique and ubiquitous NOTCH effector RBPJ in the early cardiomyocytes progenitors, and examined its consequences in cardiac development and function. Our results demonstrate that mice with cTnT-Cre-mediated myocardial-specific deletion of Rbpj develop to term, with homozygous mutant animals showing normal expression of cardiac development markers, and normal adult heart function. Similar observations have been obtained after Notch1 deletion with cTnT-Cre. We have also deleted Rbpj in both myocardial and endocardial progenitor cells, using the Nkx2.5-Cre driver, resulting in ventricular septal defect (VSD), double outlet right ventricle (DORV), and bicuspid aortic valve (BAV), due to NOTCH signaling abrogation in the endocardium of cardiac valves territories. Our data demonstrate that NOTCH-RBPJ inactivation in the myocardium does not affect heart development or adult cardiac function.

developmental biology↗