Fetal Blood Flow and Genetic Mutations in Conotruncal Congenital Heart Disease.

In congenital heart disease, the presence of structural defects affects blood flow in the heart and circulation. However, because the fetal circulation bypasses the lungs, fetuses with cyanotic heart defects can survive in utero but need prompt intervention to survive after birth. Tetralogy of Fallot and persistent truncus arteriosus are two of the most significant conotruncal heart defects.

Protein isolation from the developing embryonic mouse heart valve region.

Western blot analysis is a commonly employed technique for detecting and quantifying protein levels. However, for small tissue samples, this analysis method may not be sufficiently sensitive to detect a protein of interest. To overcome these difficulties, we examined protocols for obtaining protein from adult human cardiac valves and modified these protocols for the developing early embryonic mouse counterparts.

The role of BMPs in endothelial cell function and dysfunction.

The bone morphogenetic protein (BMP) family of proteins has a multitude of roles throughout the body. In embryonic development, BMPs promote endothelial specification and subsequent venous differentiation. The BMP pathway also plays important roles in the adult vascular endothelium, promoting angiogenesis and mediating shear and oxidative stress.

Isolation of embryonic ventricular endothelial cells.

Cell culture has greatly enhanced our ability to assess individual populations of cells under myriad culture conditions. While immortalized cell lines offer significant advantages for their ease of use, these cell lines are unavailable for all potential cell types. By isolating primary cells from a specific region of interest, particularly from a transgenic mouse, more nuanced studies can be performed.

A novel ex vivo culture method for the embryonic mouse heart.

Developmental studies in the mouse are hampered by the inaccessibility of the embryo during gestation. Thus, protocols to isolate and culture individual organs of interest are essential to provide a method of both visualizing changes in development and allowing novel treatment strategies. To promote the long-term culture of the embryonic heart at late stages of gestation, we developed a protocol in which the excised heart is cultured in a semi-solid, dilute Matrigel.

Development of a new positron emission tomography tracer for targeting tumor angiogenesis: synthesis, small animal imaging, and radiation dosimetry.

Angiogenesis plays a key role in cancer progression and correlates with disease aggressiveness and poor clinical outcomes. Affinity ligands discovered by screening phage display random peptide libraries can be engineered to molecularly target tumor blood vessels for noninvasive imaging and early detection of tumor aggressiveness. In this study, we tested the ability of a phage-display-selected peptide sequence recognizing specifically bone marrow- derived pro-angiogenic tumor-homing cells, the QFP-peptide, radiolabeled with 64Cu radioisotope to selectively image tumor vasculature in vivo by positron emission tomography (PET).

BMPER regulates cardiomyocyte size and vessel density in vivo.

Background: BMPER, an orthologue of Drosophila melanogaster Crossveinless-2, is a secreted factor that regulates bone morphogenetic protein activity in endothelial cell precursors and during early cardiomyocyte differentiation. Although previously described in the heart, the role of BMPER in cardiac development and function remain unknown.

Methods: BMPER-deficient hearts were phenotyped histologically and functionally using echocardiography and Doppler analysis.

LRP1-dependent endocytic mechanism governs the signaling output of the bmp system in endothelial cells and in angiogenesis.

Rationale: Among the extracellular modulators of Bmp (bone morphogenetic protein) signaling, Bmper (Bmp endothelial cell precursor-derived regulator) both enhances and inhibits Bmp signaling. Recently we found that Bmper modulates Bmp4 activity via a concentration-dependent, endocytic trap-and-sink mechanism.

Objective: To investigate the molecular mechanisms required for endocytosis of the Bmper/Bmp4 and signaling complex and determine the mechanism of Bmper's differential effects on Bmp4 signaling.

Bmper inhibits endothelial expression of inflammatory adhesion molecules and protects against atherosclerosis.

Objective: Bone morphogenetic proteins (Bmps) are important mediators of inflammation and atherosclerosis, though their mechanism of action is not fully understood. To better understand the contribution of the Bmp signaling pathway in vascular inflammation, we investigated the role of Bmper (Bmp endothelial cell precursor-derived regulator), an extracellular Bmp modulator, in an induced in vivo model of inflammation and atherosclerosis.

Methods And Results: We crossed apolipoprotein E-deficient (ApoE(-/-)) mice with mice missing 1 allele of Bmper (Bmper(+/-) mice used in the place of Bmper(-/-) mice that die at birth) and measured the development of atherosclerosis in mice fed a high-fat diet.

BMP signaling modulates hedgehog-induced secondary heart field proliferation.

Sonic hedgehog signaling in the secondary heart field has a clear role in cardiac arterial pole development. In the absence of hedgehog signaling, proliferation is reduced in secondary heart field progenitors, and embryos predominantly develop pulmonary atresia. While it is expected that proliferation in the secondary heart field would be increased with elevated hedgehog signaling, this idea has never been tested.

Development of the endothelium: an emphasis on heterogeneity.

The endothelium is composed of specialized epithelial cells that line the vasculature, the lymph vessels, and the heart. These endothelial cells are characterized by their stratification and are connected via intercellular junctions that confer specific permeability. Although all endothelium acts as a barrier, considerable heterogeneity exists among different organs and even within vessels.

Gyrate: CCM3 dances with a different angiogenic partner.

A healthy vasculature is an essential component of development and is regulated by different signaling pathways. One of the most critical pathways involved is the vascular endothelial growth factor (VEGF) pathway. Components of this pathway serve as the first marker of primitive endothelial cells and are instrumental in inducing the initial differentiation of endothelial cells and later refining them into either arteries or veins.

The role of secondary heart field in cardiac development.

Although de la Cruz and colleagues showed as early as 1977 that the outflow tract was added after the heart tube formed, the source of these secondarily added cells was not identified for nearly 25 years. In 2001, three pivotal publications described a secondary or anterior heart field that contributed to the developing outflow tract. This review details the history of the heart field, the discovery and continuing elucidation of the secondarily adding myocardial cells, and how the different populations identified in 2001 are related to the more recent lineage tracing studies that defined the first and second myocardial heart fields/lineages.

Sonic hedgehog maintains proliferation in secondary heart field progenitors and is required for normal arterial pole formation.

The Sonic hedgehog (Shh)-null mouse was initially described as a phenotypic mimic of Tetralogy of Fallot with pulmonary atresia (Washington Smoak, I., Byrd, N.A.