Cardiac progenitors auto-regulate second heart field cell fate via Wnt secretion

Proper heart formation requires coordinated development of two anatomically distinct groups of cells - the first and second heart fields (FHF and SHF). Given that congenital heart defects are often restricted to derivatives of the FHF or SHF, it is crucial to understand the mechanisms controlling their development. Wnt signaling has previously been implicated in SHF proliferation; however, the source of Wnts remains unknown. Through comparative gene analysis, we found upregulation of Wnts and Wnt receptor/target genes in the FHF and SHF, respectively, raising the possibility that early cardiac progenitors may secrete Wnts to influence SHF cell fate. To probe this further, we deleted Wntless (Wls), a gene required for Wnt ligand secretion, in various populations of precardiac cells. Deletion of Wls in Mesp1+ cells resulted in formation of a single chamber heart with left ventricle identity, implying compromised SHF development. This phenotype was recapitulated by deleting Wls in cells expressing Islet1, a pan-cardiac marker. Similarly, Wls deletion in cells expressing Nkx2.5, a later-expressed pan-cardiac marker, resulted in hypoplastic right ventricle, a structure derived from the SHF. However, no developmental defects were observed when deleting Wls in SHF progenitors. To gain mechanistic insights, we isolated Mesp1-lineage cells from developing embryos and performed single-cell RNA-sequencing. Our comprehensive single cell transcriptome analysis revealed that Wls deletion dysregulates developmental trajectories of both anterior and posterior SHF cells, marked by impaired proliferation and premature differentiation. Together, these results demonstrate a critical role of local precardiac mesodermal Wnts in SHF fate decision, providing fundamental insights into understanding heart field development and chamber formation.Significance StatementThere is significant interest in understanding the mechanisms underlying heart formation to develop treatments and cures for patients suffering from congenital heart disease. In particular, we were interested in the intricacies of first (FHF) and second heart field (SHF) development, as many congenital heart defects present with heart field-specific etiologies. Here, we uncovered a novel relationship between specified cardiac progenitor cells and second heart field progenitors. Through genetic manipulation of Wnt secretion in developing mouse embryos, we identified a population of cardiac progenitor cells that acts as a local source of Wnts which are necessary for proper SHF development. Our single cell transcriptomic analysis of developing anterior mesoderm showed cardiac progenitor-secreted Wnts function through regulation of differentiation and proliferation among SHF progenitors. Thus, this study provides insight into the source and timing of Wnts required for SHF development, and points to the crucial role of co-developing cell populations in heart development.

Download Full-text

Cardiac embryogenesis

ESC CardioMed ◽

10.1093/med/9780198784906.003.0004_update_001 ◽

2018 ◽

pp. 33-36

Author(s):

Robert G. Kelly

Keyword(s):

Progenitor Cells ◽

Progenitor Cell ◽

Congenital Heart ◽

Heart Defects ◽

Embryonic Heart ◽

Heart Tube ◽

Second Heart Field ◽

Heart Field ◽

Cell Niche ◽

The Right

The embryonic heart forms in anterior lateral splanchnic mesoderm and is derived from Mesp1-expressing progenitor cells. During embryonic folding, the earliest differentiating progenitor cells form the linear heart tube in the ventral midline. The heart tube extends in length and loops to the right as new myocardium is progressively added at the venous and arterial poles from multipotent second heart field cardiovascular progenitor cells in contiguous pharyngeal mesoderm. While the linear heart tube gives rise to the left ventricle, the right ventricle, outflow tract, and a large part of atrial myocardium are derived from the second heart field. Progressive myocardial differentiation is controlled by intercellular signals within the progenitor cell niche. The embryonic heart is the template for septation and growth of the four-chambered definitive heart and defects in progenitor cell deployment result in a spectrum of common forms of congenital heart defects.

Download Full-text

Maternal hyperglycemia impedes second heart field-derived cardiomyocyte differentiation to elevate the risk of congenital heart defects

10.1101/2021.05.28.446177 ◽

2021 ◽

Author(s):

Sathiyanarayanan Manivannan ◽

Corrin Mansfield ◽

Xinmin Zhang ◽

Karthik M. Kodigepalli ◽

Uddalak Majumdar ◽

...

Keyword(s):

Congenital Heart ◽

Heart Defects ◽

Lineage Tracing ◽

Ventricular Wall ◽

Cardiomyocyte Differentiation ◽

Glucose Levels ◽

Second Heart Field ◽

Maternal Hyperglycemia ◽

Wall Thinning ◽

Heart Field

Congenital heart disease (CHD) is the most frequently occurring structural malformations of the heart affecting ~1% of live births. Besides genetic predisposition, embryonic exposure to teratogens during pregnancy increases the risk of CHD. However, the dose and cell-type-specific responses to an adverse maternal environment remain poorly defined. Here, we report a dose-response relationship between maternal glucose levels and phenotypic severity of CHD in offspring, using a chemically-induced pregestational diabetes mellitus (PGDM) mouse model. Embryos from dams with low-level maternal hyperglycemia (matHG) displayed trabeculation defects, ventricular wall thinning, and ventricular septal defects (VSD). On the other hand, embryos from dams with high-level matHG display outflow tract malformations, ventricular wall thinning and an increased rate of VSD. Our findings show that increasing levels of matHG exacerbates CHD occurrence and severity in offspring compared to control embryos. We applied single-cell RNA- sequencing to define matHG-related transcriptional differences in E9.5 and E11.5 hearts as comparing to controls. Disease-dependent gene-expression changes were observed in Isl1+ second heart field (SHF) and Tnnt2+ cardiomyocyte subpopulations. Lineage tracing studies in Isl1-Cre; RosamTmG embryonic hearts showed Isl1+-SHF-derived cardiomyocyte differentiation was impaired with matHG. This study highlights the influence of matHG-dosage on cardiac morphogenesis and identifies perturbations in the Isl1-dependent gene-regulatory network that affect SHF-derived cardiomyocyte differentiation contributing to matPGDM-induced CHD.

Download Full-text

Cardiac embryogenesis

ESC CardioMed ◽

10.1093/med/9780198784906.003.0004 ◽

2018 ◽

pp. 33-36

Author(s):

Robert G. Kelly

Keyword(s):

Progenitor Cells ◽

Progenitor Cell ◽

Congenital Heart ◽

Heart Defects ◽

Embryonic Heart ◽

Heart Tube ◽

Second Heart Field ◽

Heart Field ◽

Cell Niche ◽

The Right

Download Full-text

Functional Role of Second Heart Field-derived Smooth Muscle Cells in Thoracic Aortopathies in Mice

10.1101/2020.02.02.930917 ◽

2020 ◽

Author(s):

Hisashi Sawada ◽

Hideyuki Higashi ◽

Chen Zhang ◽

Yanming Li ◽

Yuriko Katsumata ◽

...

Keyword(s):

Smooth Muscle ◽

Angiotensin Ii ◽

Smooth Muscle Cells ◽

Neural Crest ◽

Single Cell ◽

Proteomic Analysis ◽

Ascending Aorta ◽

Second Heart Field ◽

Heart Field

AbstractBackgroundThe ascending aorta is a common location for thoracic aortopathies. Pathology predominates in the aortic media with disease severity being most apparent in outer laminar layers. In the ascending aorta, smooth muscle cells (SMCs) are derived from two embryonic origins: cardiac neural crest and second heart field (SHF). SMCs of these origins have distinct distributions, and the localization of SHF coincides with the regional specificity in some forms of thoracic aortopathies. However, the role of SHF-derived SMCs in maintaining the structural and functional integrity of the ascending aorta remains unclear.MethodsMass spectrometry assisted proteomic and single cell transcriptomic analyses were performed in mouse aortas to discriminate molecular features of SHF-derived SMCs in maintaining the aortic homeostasis. Genetic deletion of low-density lipoprotein receptor-related protein 1 (Lrp1) or transforming growth factor-β receptor 2 (Tgfbr2) in SHF-derived SMCs was conducted to examine impact of SHF-derived SMCs on the development of thoracic aortopathies.ResultsProteomic analysis did not detect differences in protein profiles between ascending (disease prone) and descending (disease resistant) thoracic aortas in saline-infused mice. However, angiotensin II infusion altered these profiles in a region-specific manner. Angiotensin II evoked differential expression of multiple LRP1 ligands. Histological analysis demonstrated that angiotensin II-induced medial disruptions were detected mainly in outer laminar layers derived from the SHF. Single cell RNA sequencing using normal mouse aortas revealed lower abundance of elastin mRNA in SHF-derived SMCs compared to SMCs from the cardiac neural crest. In addition, Lrp1 and Tgfbr2 mRNA were abundant in SHF-derived SMCs. To examine biological effects of SHF-derived cells, Lrp1 or Tgfbr2 was deleted in SHF-derived cells in mice. SHF-specific Lrp1 deletion augmented angiotensin II-induced aortic aneurysm and rupture in the ascending region. Proteomic analysis discerned regulation of protein abundances related to TGF-β signaling pathways by Lrp1 deletion in SHF-derived cells. Deletion of Tgfbr2, a key regulator of TGF-β signaling, in SHF-derived cells led to embryonic lethality at E12.5 with dilatation of the outflow tract and retroperitoneal hemorrhage in mice.ConclusionThese results demonstrate that SMCs derived from the SHF play a critical role in the integrity of the ascending aortic wall.

Download Full-text

Outflow Tract Formation—Embryonic Origins of Conotruncal Congenital Heart Disease

Journal of Cardiovascular Development and Disease ◽

10.3390/jcdd8040042 ◽

2021 ◽

Vol 8 (4) ◽

pp. 42

Author(s):

Sonia Stefanovic ◽

Heather C. Etchevers ◽

Stéphane Zaffran

Keyword(s):

Congenital Heart ◽

Cardiac Development ◽

Heart Defects ◽

Dynamic Structure ◽

Cell Types ◽

Outflow Tract ◽

Heart Tube ◽

Heart Field ◽

Multiple Cell ◽

The Many

Anomalies in the cardiac outflow tract (OFT) are among the most frequent congenital heart defects (CHDs). During embryogenesis, the cardiac OFT is a dynamic structure at the arterial pole of the heart. Heart tube elongation occurs by addition of cells from pharyngeal, splanchnic mesoderm to both ends. These progenitor cells, termed the second heart field (SHF), were first identified twenty years ago as essential to the growth of the forming heart tube and major contributors to the OFT. Perturbation of SHF development results in common forms of CHDs, including anomalies of the great arteries. OFT development also depends on paracrine interactions between multiple cell types, including myocardial, endocardial and neural crest lineages. In this publication, dedicated to Professor Andriana Gittenberger-De Groot and her contributions to the field of cardiac development and CHDs, we review some of her pioneering studies of OFT development with particular interest in the diverse origins of the many cell types that contribute to the OFT. We also discuss the clinical implications of selected key findings for our understanding of the etiology of CHDs and particularly OFT malformations.

Download Full-text

Abstract 257: Clonal Analysis Of Multipotent Cardiovascular Progenitors That Generate Cardiomyocytes During Development

Circulation Research ◽

10.1161/res.115.suppl_1.257 ◽

2014 ◽

Vol 115 (suppl_1) ◽

Author(s):

Konstantina Ioanna Sereti ◽

Paniz Kamran Rashani ◽

Peng Zhao ◽

Reza Ardehali

Keyword(s):

Single Cell ◽

Heart Development ◽

Cardiac Development ◽

Clonal Analysis ◽

Cardiac Cells ◽

Single Cell Level ◽

Reporter System ◽

Cell Level ◽

Cardiac Progenitors

It has been proposed that cardiac development in lower vertebrates is driven by the proliferation of cardiomyocytes. Similarly, cycling myocytes have been suggested to direct cardiac regeneration in neonatal mice after injury. Although, the role of cardiomyocyte proliferation in cardiac tissue generation during development has been well documented, the extent of this contribution as well as the role of other cell types, such as progenitor cells, still remains controversial. Here we used a novel stochastic four-color Cre-dependent reporter system (Rainbow) that allows labeling at a single cell level and retrospective analysis of the progeny. Cardiac progenitors expressing Mesp1 or Nkx2.5 were shown to be a source of cardiomyocytes during embryonic development while the onset of αMHC expression marked the developmental stage where the capacity of cardiac cells to proliferate diminishes significantly. Through direct clonal analysis we provide strong evidence supporting that cardiac progenitors, as opposed to mature cardiomyocytes, are the main source of cardiomyocytes during cardiac development. Moreover, we have identified quadri-, tri-, bi, and uni-potent progenitors that at a single cell level can generate cardiomyocytes, fibroblasts, endothelial and smooth muscle cells. Although existing cardiomyocytes undergo limited proliferation, our data indicates that it is mainly the progenitors that contribute to heart development. Furthermore, we show that the limited proliferation capacity of cardiomyocytes observed during normal development was enhanced following neonatal cardiac injury allowing almost complete regeneration of the scared tissue. However, this ability was largely absent in adult injured hearts. Detailed characterization of dividing cardiomyocytes and proliferating progenitors would greatly benefit the development of novel therapeutic options for cardiovascular diseases.

Download Full-text

Role of Ultrasonography in Early Gestation in the Diagnosis of Congenital Heart Defects

Journal of Ultrasound in Medicine ◽

10.7863/jum.2010.29.5.817 ◽

2010 ◽

Vol 29 (5) ◽

pp. 817-821 ◽

Cited By ~ 7

Author(s):

Reem S. Abu-Rustum ◽

Linda Daou ◽

Sameer E. Abu-Rustum

Keyword(s):

Congenital Heart Defects ◽

Congenital Heart ◽

Heart Defects ◽

Early Gestation

Download Full-text

The Role of Telemedicine in Paediatric Cardiology

Telehealth Networks for Hospital Services ◽

10.4018/978-1-4666-2979-0.ch004 ◽

2013 ◽

pp. 44-88

Author(s):

Brian A. McCrossan ◽

Frank A. Casey

Keyword(s):

Economic Evaluation ◽

Medical Imaging ◽

Congenital Heart Defects ◽

Congenital Heart ◽

Heart Defects ◽

Pilot Project ◽

Clinical Service ◽

Current Evidence ◽

Paediatric Cardiology

Paediatric cardiology is a subspecialty ideally suited to telemedicine. A small number of experts cover large geographical areas and the diagnosis of congenital heart defects is largely dependent on the interpretation of medical imaging. Telemedicine has been applied to a number of areas within paediatric cardiology. However, its widespread uptake has been slow and fragmentary. In this chapter the authors examine the current evidence pertaining to telemedicine applied to paediatric cardiology, including their own experience, the importance of research and, in particular, economic evaluation in furthering telemedicine endeavours. Perhaps most importantly, they discuss the issues relating transitioning a pilot project into a sustainable clinical service.

Download Full-text

Tbx1 regulates extracellular matrix-cell interactions in the second heart field

Human Molecular Genetics ◽

10.1093/hmg/ddz058 ◽

2019 ◽

Vol 28 (14) ◽

pp. 2295-2308 ◽

Cited By ~ 10

Author(s):

Daniela Alfano ◽

Alessandra Altomonte ◽

Claudio Cortes ◽

Marchesa Bilio ◽

Robert G Kelly ◽

...

Keyword(s):

Extracellular Matrix ◽

Cultured Cells ◽

Time Window ◽

Outflow Tract ◽

Mouse Embryos ◽

Cell Interactions ◽

Deletion Syndrome ◽

Cardiac Progenitors ◽

Second Heart Field ◽

Heart Field

Abstract Tbx1, the major candidate gene for DiGeorge or 22q11.2 deletion syndrome, is required for efficient incorporation of cardiac progenitors of the second heart field (SHF) into the heart. However, the mechanisms by which TBX1 regulates this process are still unclear. Here, we have used two independent models, mouse embryos and cultured cells, to define the role of TBX1 in establishing morphological and dynamic characteristics of SHF in the mouse. We found that loss of TBX1 impairs extracellular matrix (ECM)-integrin-focal adhesion (FA) signaling in both models. Mosaic analysis in embryos suggested that this function is non-cell autonomous, and, in cultured cells, loss of TBX1 impairs cell migration and FAs. Additionally, we found that ECM-mediated integrin signaling is disrupted upon loss of TBX1. Finally, we show that interfering with the ECM-integrin-FA axis between E8.5 and E9.5 in mouse embryos, corresponding to the time window within which TBX1 is required in the SHF, causes outflow tract dysmorphogenesis. Our results demonstrate that TBX1 is required to maintain the integrity of ECM-cell interactions in the SHF and that this interaction is critical for cardiac outflow tract development. More broadly, our data identifies a novel TBX1 downstream pathway as an important player in SHF tissue architecture and cardiac morphogenesis.

Download Full-text