Arriving to Rice Biosciences Department October 2017!
Zebrafish as a simple model to understand enteric nervous system formation, neural crest stem cells and cancer development
Globally, we are interested in the mechanisms that underly the migration, proliferation and differentiation of neural crest cells along the gut, as well as understanding the role of the tissue microenvironment in influencing fate choices and the development of cancer in vivo.
One area of lab research focus is on understanding how the largest division of the peripheral nervous system, the Enteric Nervous System (ENS), is constructed during embryonic development from a stem cell population called the Neural Crest. The ENS is composed of thousands of ganglia embedded within the walls of the gut. Each ganglia consists of diverse enteric neuron subtypes and glial cells, which together regulates gut peristalsis, water balance and hormone secretions. The number of neurons found within the ENS rivals the numbers of those found in the spinal cord, causing it to also be known as "the second brain." It is important to study development of the ENS so that we can understand not only how it forms and functions, but also to help us to understand how things go wrong in various gastrointestinal disease states (Hirschsprung disease, Achalasia), as well as neural crest stem cell defects, such as when neural crest become cancerous.
During zebrafish embryogenesis, neural crest cells, a migratory stem cell population, migrate into the primitive gut in two chains (as depicted below in schematic and timelapse video), eventually surround the gut tube and turn into neurons by the 5th day in development in order to form the ENS. Zebrafish are an excellent model system to investigate ENS development due to their rapid, transparent development, amenability to genetic manipulation and high-resolution live imaging. As shown in the cartoon and images below, zebrafish ENS development is rapid and enteric neurons are easily detected as early as a few days post fertilization (dpf).
Collectively, it is our aim to study neural crest stem cell development and nervous system formation, and to relate this to the ontogenesis of neural crest-derived cancer. For current projects, please click the current projects tab, above.
Neural crest cells, marked by membrane Red Fluorescent Protein (RFP) migrate in chains posteriorly along the gut tube (in the center of the embryo) during the second day in development. The front of the migratory chains are seen progressing at a rate of ~30 microns/hour. Anterior (toward head) to left, posterior to the right (toward tail). Movie originally published in "Meis3 is required for neural crest invasion of the gut during zebrafish enteric nervous system development", Molecular Biology of the Cell 2015
3D animation to show the gut tube of a 3 dpf larval fish. Freshly born enteric neurons are shown by expression of Phox2b (green) and HuC/D (red).
Short movie of gut peristalsis in a 6 dpf larval fish. A small bolus of digesting food is seen traveling through the midgut in the gut tube (top of image). Posterior to the left.