2016 — 2018 |
Piacentino, Michael Louis |
F32Activity Code Description: To provide postdoctoral research training to individuals to broaden their scientific background and extend their potential for research in specified health-related areas. |
Determining the Position and Role of Mafb and Krox20 in the Cardiac Neural Crest Cell Gene Regulatory Program @ California Institute of Technology
? DESCRIPTION (provided by applicant): The cardiac neural crest is a unique population of cells that undergo extensive migration through the embryo and contribute to many aspects of cardiac development, including the formation of the interventricular septum, the partitioning of the cardiac outflow tract, and the development of the heart valves. Defects in cardiac neural crest are at the root of many congenital heart defects found in live births, and these issues often require surgical repair. Despite this clear importance in human development, our understanding of cardiac neural crest biology remains incomplete. Here we propose to determine the role of two transcription factors, MafB and Krox20, in the development of the cardiac neural crest. Interestingly, these two factors are expressed in the migrating cardiac neural crest, and not in other migrating neural crest populations, suggesting that they play specific roles in cardiac neural crest development. As transcription factors, MafB and Krox20 function to regulate expression of additional genes, and thereby they can have broad impacts on the behavior of the cardiac neural crest cells. By eliminating MafB and Krox20 function in the chick cardiac neural crest we will identify any resulting defects. We hypothesize that loss of MafB or Krox20 will result in cardiac defects that closely resemble many congenital heart defects, and thereby demonstrate the importance of these gene products for normal cardiac neural crest development. To achieve these goals, we will examine not only cardiac morphology, but also the migratory path taken by the cardiac neural crest cells, as well as the expression of target downstream genes through candidate-based and systems-level experiments. We will also identify important transcriptional inputs into MafB and Krox20 expression. Following these experiments, we will assemble a gene regulatory network model that describes the cascade of gene expression upstream and downstream of MafB and Krox20 in the cardiac neural crest, and provides the necessary framework to determine what makes the cardiac neural crest unique from other neural crest linages. This knowledge will inform future studies in which other neural crest cells will be reprogrammed to compensate for loss of cardiac neural crest, and thereby rescue cardiac neural crest-related congenital heart defects.
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2019 — 2021 |
Piacentino, Michael Louis |
K99Activity Code Description: To support the initial phase of a Career/Research Transition award program that provides 1-2 years of mentored support for highly motivated, advanced postdoctoral research scientists. |
Characterizing the Neural Crest Response to Bmp Signaling Through Gastrulation and Neurulation @ California Institute of Technology
PROJECT SUMMARY The cranial neural crest (NC) contributes to the formation of many craniofacial structures including the bones and cartilage of the face, tooth dentin and peripheral ganglia. Cell signaling regulates different aspects of cranial NC specification, epithelial-to-mesenchymal transition (EMT) and differentiation and disruptions in this developmental program results in many cranial NC-derived craniofacial birth defects including craniosynestosis, Treacher Collins and CHARGE syndromes, and cleft palate. BMP signaling plays a crucial role during the specification and differentiation of cranial NC, and more recently, BMP signaling was shown to control cranial NC EMT. A mechanistic understanding of the role of BMP signaling during cranial NC development is essential to develop novel preventative and therapeutic measures against craniofacial defects. This proposal will determine the molecular mechanism of BMP gradient formation in the chick gastrula, and how this gradient regulates the formation of cranial cell types including neural, cranial NC, placode and epidermal fates. These experiments will use in vivo and in silico approaches to test the hypothesis that extracellular BMP ligands are produced primarily by the cranial NC and are actively shuttled over long distances to signal most strongly in the nonneural ectoderm. Next, quantitative expression analysis and live imaging will be used to establish the timeline of BMP signaling during gastrulation and neurulation, and analysis of the resulting datasets will determine population- and single-cell-level responses to BMP signals. Differences in signal timing and strength will then be correlated with direct input into different target genes. Finally, the role of BMP target genes Id1/2/3/4 and Fibin during cranial NC EMT will be investigated using in vivo functional analyses. Together, the results of these aims will provide a comprehensive understanding of the regulation and roles of BMP signaling events during early cranial NC development. In addition to identifying targets for translational avenues to prevent craniofacial birth defects, the mentored phase of this proposal will provide Dr. Michael Piacentino with necessary training as he prepares to begin his independent career. Dr. Marianne Bronner's lab at California Institute of Technology, and his assembled advisory council, provide the necessary tools, expertise, and training environment to efficiently execute the proposed aims and establish Dr. Piacentino's independence. This training will be instrumental as Dr. Piacentino begins his independent research program and will provide the experience needed to make lasting impacts on the field of BMP signaling during craniofacial development.
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