Citation:

Hunter, S., K. Grode, A. Schwab, AND T. Knudsen. Recapitulating Human Endocardial Cushion Morphogenesis with OCMs and Microfluidics. Teratology Society Meeting, ClearWater, FL, June 23 - 28, 2018.

Impact/Purpose:

The potential for chemical exposure to produce developmental toxicity has not been evaluated for thousands of chemicals; therefore, experimental and computational models are needed to prioritize untested chemicals. Heart defects are among the most common structural malformations in humans and affect as many as 40,000 newborns in the US each year. Although there are many targets associated with heart defects, endocardial cushions are important structures in the genesis of heart malformations. Endocardial cushions form as paired outgrowths of the cardiac tube and their development includes the induction of mesenchyme cells from the endocardium. In our model, human endothelial (hE) cells (e.g. human endothelial umbilical vein cells (HUVECs)) are used as a substitute for embryonic endocardial cells, since endocardial cells are not commercially available. hE cells placed onto a fibronectin-coated collagen matrix form endothelial cellular sheets that display tight junctions and appropriate cellular morphology. Formation of mesenchymal cells from endothelial cells (endothelial mesenchymal transition (EndMT)) is critical for endocardial cushion morphogenesis and is under the regulation of transforming growth factor beta (TGFb) family signals. TGFb 1, in a medium without fibroblast growth factor and VEGF supplements, variably induced EndMT in some hE cell subtypes. Thus, hE cells in 2D culture did not reliably recapitulate EndMT induction needed to create an experimental model of endocardial cushions. Another factor, that is critical to normal heart development, is mechanical stress on hE cells produced by blood flow through the heart tube. Using ibidi TM microfluidic chambers, HUVECs exposed to media flow (20 ml/min flow rate) align to the direction of flow, a process that was affected by chemicals added to the medium. Thus, HUVECs respond to physiological stressors; and our hypothesis is that cells in a “flow-induced state” makes them sensitive to growth factor-induced EndMT. Our goal is to construct a 3-dimensional human multicellular model to recapitulate the early events of endocardial cushion formation and development. We propose that this model will be important in assessing the potential for toxicants to disrupt early cardiogenesis and ultimately identify potential developmental cardiotoxicants. This abstract does not present EPA policy.

Description:

The potential for chemical exposure to produce developmental toxicity has not been evaluated for thousands of chemicals; therefore, experimental and computational models are needed to prioritize untested chemicals. Heart defects are among the most common structural malformations in humans and affect as many as 40,000 newborns in the US each year. Although there are many targets associated with heart defects, endocardial cushions are important structures in the genesis of heart malformations. Endocardial cushions form as paired outgrowths of the cardiac tube and their development includes the induction of mesenchyme cells from the endocardium. In our model, human endothelial (hE) cells (e.g. human endothelial umbilical vein cells (HUVECs)) are used as a substitute for embryonic endocardial cells, since endocardial cells are not commercially available. hE cells placed onto a fibronectin-coated collagen matrix form endothelial cellular sheets that display tight junctions and appropriate cellular morphology. Formation of mesenchymal cells from endothelial cells (endothelial mesenchymal transition (EndMT)) is critical for endocardial cushion morphogenesis and is under the regulation of transforming growth factor beta (TGFb) family signals. TGFb 1, in a medium without fibroblast growth factor and VEGF supplements, variably induced EndMT in some hE cell subtypes. Thus, hE cells in 2D culture did not reliably recapitulate EndMT induction needed to create an experimental model of endocardial cushions. Another factor, that is critical to normal heart development, is mechanical stress on hE cells produced by blood flow through the heart tube. Using ibidi TM microfluidic chambers, HUVECs exposed to media flow (20 ml/min flow rate) align to the direction of flow, a process that was affected by chemicals added to the medium. Thus, HUVECs respond to physiological stressors; and our hypothesis is that cells in a “flow-induced state” makes them sensitive to growth factor-induced EndMT. Our goal is to construct a 3-dimensional human multicellular model to recapitulate the early events of endocardial cushion formation and development. We propose that this model will be important in assessing the potential for toxicants to disrupt early cardiogenesis and ultimately identify potential developmental cardiotoxicants. This abstract does not present EPA policy.

Record Details: